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HURST SPIT
SECTION 1. - INTRODUCTION
This is large shingle spit extending southeast from the end of Christchurch Bay, formerly the deposition area of shingle from the cliffs of Christchurch Bay. Highcliffe has long ago, lost part of Highcliffe Castle, but erosion has slowed in recent years. Sand has come from Hengisbury Head and Poole Bay. Since the 1930s the coast of this bay has been very much built up, particularly at Barton-on-Sea and at Milford-on-Sea by suburban housing. At Milford-on-Sea, some buildings from about the 1930s were built too close to the cliff line (although some are not). The coast has now eroded back to some of what seemed safe in the 1930s.
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[To what extent is this road becoming progressively more deeply flooded as a result of slowly rising sea level; I do not know the exact date when this road was tarmacked but perhaps we see the local effects of at least 50 years of slow rise.]
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The spit is an excellent place for studying geomorphology and is also very good just for an interesting and breezy walk along the shingle. Apart from features of geomorphological and geological interest there are extensive marshes with interesting wading birds, salt-marsh and shingle beach plant live, shipping to watch, a view of the Isle of Wight, and, of course, there is the history. This includes the initiation of the castle by King Henry VIII and the later imprisonment here of King Charles I. Consult the interesting book of James (1986) for information on the history. Incidently King Charles used to take his exercise walking along the spit. He was removed from the castle in December 1648 by Corronell Harrison with no less than 1200 or 1400 horse (brought through the New Forest from Lyndhurst). The King was on his way to execution. The castle is well-worth visiting and is quite atmospheric, especially in stormy conditions.
SECTION 2 - INTRODUCTION - EXTRACTS - LOCAL AUTHORITY
2.1. New Forest District Council
"Hurst Spit is a place of erosion risk and a place where construction of major sea defences has taken place and where, from time to time, further works can take place.
This website is not concerned with the details of the civil engineering aspects, or matters concerned with or relating to the costing of these or matters of liability. This website is only for educational and geological/geomorphological purposes and has no interest or concern regading details of Local Authority matters; it is not at all a complete survey and takes no sides in any possible disputes or disagreements and is only objectively observational.
[EXTRACTS - "COASTAL DEFENCES AND NEW FOREST DISTRICT COUNCIL - see the full report]
"Coast protection works, that is works to prevent erosion and encroachment by the sea,
are carried out under the Coast Protection Act 1949, which applies to the coastline of Great Britain. Powers to carry out works are mainly invested in 88 maritime district
councils in England, 22 in Wales and 11 regional and island councils in Scotland." ..continues."
"EXISTING DEFENCES
Of a total length of coastline of 50km about 24.1km has some form of protection and of
this, 4.7km is maintained by the District Council. Historically, the protection of the coastline in the NFDC area has relied upon a regular supply of material being transported along the shore by natural forces (littoral drift). The precise mechanisms are difficult to define, especially in relation to the circulation of material within Christchurch Bay, but the installation of coastal defence works to the west in Christchurch and Bournemouth has had a significant effect in reducing the amount of material available. The most serious effect was probably the severe depletion of Hurst Spit and the consequent increase in the incidence of breaching. Beach nourishment now forms part of most schemes in the New Forest. NFDC is directly responsible for existing coastal defence measures at: Barton on Sea, Milford on Sea, Hurst Spit, Calshot."
See: Coastal Defences and New Forest District Council
SECTION 3. - SAFETY
3.1 Safety and Hazards
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The obvious risk at Hurst Castle Spit is from the sea. There can at times be major storm waves with backwash. There are dangerously strong currents just offshore. Take care with regard to sea-defences and walls, particularly groynes, metal objects and rock armour. Flint pebbles must not be hammered because of dangerous splinters, which could cause eye-damage. There is danger of being trapped in soft mud within the harbour at the back of the spit. There might be hazards associated with attempting to round the outer seaward wall of the castle in certain tide or wave conditions. The interior of the castle is not the real subject of this geological and geomorphological description and has its own procedures and regulations and these should be abided by. Note that the bank of Hurst Spit is very exposed to wind and weather conditions and suitable protective clothing should be worn when necessary. It is generally colder and more windblown than other parts of the Hampshire coast.
Individual geological and other visitors and field leaders should make their own risk assessment at the time of an intended visit and no liability is accepted. In certain weather conditions, particularly severe storms, there may be no safe access to the far part of Hurst Spit. This webpage is descriptive and for information and does not represent advice to go to any specific places mentioned.
It could be hazardous to try to get round the outer, seaward side of Hurst Castle. In the past this was not difficult but now erosion has caused seawater to come into contact with the outer wall at the eastern part. It might be passable at very low tide but even then it might not be safe to do this. There is a very strong current here, particularly at ebb tide, and it is quite obvious that the sea is dangerous here.
Section 3.2
MILFORD AND HURST SPIT - TSUNAMI RISK - LOW BUT NOT IMPOSSIBLE
It is not impossible for, on very rare occasions, large waves, which may be tsunamis or earthquake waves, to hit the Hurst Spit, and presumably therefore Milford-on-Sea. There are occasionally, relatively mild earthquakes in the Chichester-Isle of Wight area, normally less than 5 intensity and are not normally associated with any large waves. Probably, although the matter has not been studied, a rare Atlantic Ocean tsunami wave could come up the English Channel and hit Hurst Spit. Of course, there is no record of very old ones. The main record is from 1882, almost 140 years back. At that date there would have been very little building development near the beach at Milford-on-Sea.
Cole, A. 1926. [RE TSUNAMI OF 1882] Postmaster of Milford on Sea. Some Further Recollections of Milford, no. 23. Milford-on-Sea Record Society: Occasional Magazine, Volume 3, no 4, 1926.
Quote: "In September, 1882, a tidal wave [probably a tsunami from an earthquake] broke on the beach at Sturt [Sturt Pond, Milford-on-Sea, which is the lake adjacent to the landward end of Hurst Spit] filling up a considerable portion of Sturt Pond and the outlet, the salt water came up the Dane Stream, killing the fish, roach, carp, etc., and destroyed many of the apple trees in the gardens abutting on the stream. A new cutting was made near the original, but this soon filled up and the present one [in 1926] was made."
[important event - this was the last tsunami that is known to have hit the Hurst Spit. There may have been many in the distant past.]
SECTION 4. - INTRODUCTION - GEOMORPHOLOGY
4.1 Old Maps
[maps to be added here]
General Geomorphology of the Hurst Spit and adjacent areas.
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Hurst Spit is a hook-shaped shingle spit which extends southeast for 1.4 miles or 2.25 km. from the Hampshire shore into the Solent towards the Isle of Wight. It the present example of the natural, coastal deposition area for the material, particularly Pleistocene shingle transported from the cliffs of Christchurch Bay, a coastline which eroded rapidly in natural conditions. Christchurch Bay is composed of non-resistant Eocene clays and sands (approximately 42 million years old) with Pleistocene gravel lying unconformably above.
The gravel is important as the main supply of shingle to Hurst Spit. The Pleistocene, periglacial deposit occurs in non-overlapping terraces in deposits of about three metres thick. The flint gravel is composed predominantly of brown-stained, worn, subangulr, conchoidally fractured flint pebbles. There is a smaller proportion of very rounded pebbles (still showing the curves of conchoidal fractures) that have ultimately come from the underlying Eocene strata, but have often been incorporated in the Pleistocene gravel.
Originally almost all the cliffs of Christchurch Bay were supplying shingle to Hurst Spit. This bay, Christchurch Bay is the youngest bay in the area. This process of transport of pebbles by longshore drift has been taking place for some time because there is the Shingles Bank, an approximately 7.5 kilometre extension of gravel on the sea floor southeast of Hurst Spit and Milford-on-Sea
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SECTION 5 - SHINGLE CHARACTERISTICS - summarised
5.1. Shingle Pebbles
The pebbles are almost all of flint, ultimately having come from eroded Cretaceous Chalk of the area. They consist of dominantly subangular flint pebbles with a smaller proportion of rounded flint pebbles, with worn off conchoidal fractures.
SECTION 6 - SHINGLE SOURCE MATERIAL
6.1. Pleistocene Gravel - Introduction
The Pleistocene flint gravels occur in the top part of the cliff at Barton-on-Sea, Hordle Cliff and at Milford-on-Sea. The terraces are at various height with the older ones being higher. The main old, high terrace is at Barton with the heights decreasing to near the White House, Milford-on-Sea. [to be continued]
6.2. Offshore Shingle
The main area of offshore shingle that is relevant to Hurst Spit, is to the south of it, as shown on sea floor maps. It is a triangle, including the Shingles Bank. There is more gravel in the fairly deep West Solent, but this is probably less relevant to Hurst Spit. See Velegrakis (2000), with fig. 5 based on Bray et al.(1995)
6.3. Artificial Gravel
The artificial gravel supplied by trucks to Hurst Spit from time to time, is the usual Pleistocene gravel of local gravel pits. The flint pebble content is generally similar to that of the spit, but it has, of course, not been naturally sorted in the same way. Any sorting was by sporadic flood action during melting of the snows during the late Pleistocene. It can contain more sand and clay content than does the natural spit shingle. This makes more stable and less loose underfoot. It is easier to walk on than is the natural, well-sorted and loose shingle.
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General Introduction
An unusually high tide is seen here in very quiet conditions, but flooding the road behind Hurst Spit. I never seen it this high when there is no storm overtoppng the spit. Conditions are completely peaceful and the are no waves of any consequence. The water level is shown on the blocks of Portland Stone. Is the exceptional level the result of rising sea-level caused by global warming?
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HURST SPIT AND MILFORD-ON-SEA - SITUATION - FEBRUARY 15th 2014, DAMAGE AFTER SEVERE STORM (ST. VALENTINE'S DAY STORM).
[Serious storm damage to Hurst Spit happened at the same time of year, 14th-15th February in 2014 and 2020.]
[EROSIONAL PROBLEMS - SEAWARD SIDE OF THE CASTLE]
There is now very little, shingle beach on the seaward side of Hurst Spit. In 2018, it was not possible to pass except at very low tide. There is risk of being trapped if the tide is rising. The loss of material and the incipient erosion of the castle walls was confirmed by a low tide visit on the 22nd February 2020
In January 2018 the far end of Hurst Spit showed marine erosion down to the red bricks at the base of the heavy castle wall. This has not been seen before by the writer. It is not yet causing a major threat to the very sturdy wall. However, there is no natural supply of shingle now to this locality. Dumping of artificial gravel has taken place both on the main bank and to a lesser extend in the distal end area near here, but not on a very large scale. Even if shingle is added here it may be more likely to be washed away because of the very strong tidal currents and the deep seawater at this channel in and out of the West Solent.
[next- the far end of Castle in June 2019]
12BR [REWORKED BARTON FOSSILS]
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THE OLD PIER, DEPOSITION AND EROSION
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Events - 2013 - Night of 27th - 28th October 2013 - St. Jude's Storm
A severe storm came in from the Atlantic during the night of the 27th to 28th October, 2013. The winds were quite high for a relatively short time in the night, attaining more than 90mph at the Needles, Isle of Wight. It was damaging in the countryside to some extent, bringing down many trees. However, it was not a true hurricane causing severe destruction. It was associated with heavy rain but passed over the area fairly quickly, with the intense phase only lasting a few hours. It did not severely damage Hurst Spit as happened in the winter of 1989.
Hurst spit is more or less in usual condition at the present time, but it has suffered some damage and some change in character. The major stabilisation works of 1996-7 produced an artificial spit which imitates to some extent the original. However, there is the presence of a stretch of larvikite rock armour at the western end. This is a strong point that the sea cannot overcome and it effectively fixes the western end as though it was a rocky headland. This has not been threatended since it was constructed. It remains as a stationary area in a beach which has always been mobile and travelled landwards in this region. The far end, at Hurst Castle has for centuries been relatively stable, although in the past it was the natural tip or dumping area for the sediments from Barton-on-Sea. These are now prevented from travelling here because of the rather questionable, but historic, Barton sea defences.
So there are effectively two fixed areas at each end and a high, but artificial, shingle beach in between. One original plan to use larvikite rock armour for the full length never took place because of the high cost. Instead there is a constructed bank of gravel packed with a sand matrix. This is not natural for surviving the wave energy high on the beach. All sand was originally at or below low tide level. Any wave erosion of the top artificial bank tends to form low cliffs and to remove the sand from fallen debris. Thus, perhaps about 20 to 30% of the artificial bank is composed of sand which removable by the sea. Once the artificial bank has been fully attacked by waves, then it become lower anyway, but in part because the sand will be removed. Thus the bank will progressively become eroded and lower, but of course it might be replaced by a new artificial bank if it decided to spend the money on this.
If natural processes occur to the artificial bank with its two points at each end, then it can be regarded as a bay beach between two headlands.
Thus theoretically the Hurst Spit beach should take the form of concave curve as is normal for a shingle beach between the two rocky promontories. This is the shape of the Chesil Beach (although the Burton Cliff end in the west is a small promontory at the moment). The present seawardly convex shape of the Hurst Spit shingle beach is the result of a historic origin when it once connected through to Barton-on-Sea and aligned to some extent with the main coast of eastern Christchurch Bay. The far end part nearer the castle has an alignment relating to ancient profile of the Christchurch Bay beach. The artificial replacement beach was built on almost the original lines, with a particularly well-defined bend in the middle. This recent storm, the St Jude's Storm seems to a small extent to have started to smooth out the bend. It is reasonable to expect, but without any certainty, that the beach will move back in the central part which is unprotected by rock armour. Of course, I am not suggesting that it be placed there because it would spoil the long beach.
I do think that the beach will become concave sooner or later by moving backwards in the central part over the channel and towards the marshes. Look at the photographs and notice the increased amount of washover and the narrower beach at the inflection point.
To deal with a separate matter, there is the unexpected development after the St. Jude's Storm of a second parallel beach ridge on the seaward side. This is seen between the larvikite area and the inflection point. The reason for this is not understood, but it may have some relationship to the larvikite barrier. In general terms the (expensive) artificial ridge is being gradually destroyed and replaced by a new natural one.
The great difference in composition of the artificial ridge and the relatively natural beach should be emphasised. The artificial ridge is effectively a gravel with a matrix of sand and a small amount of mud. It is compacted and has a matrix. It is strong enough to use a roadway for vehicles travelling to and from Hurst Castle, and it is much easier to walk on than was the original loose beach.
The natural beach, in contrast, is sorted and mobile and consists only of pebbles. It is loose and not fixed by sand or mud. Thus the natural beach has no small cliffs within it, only slopes. The artificial bank, in contrast, is cliffed on the seaward side. It is being destroyed largely by undercutting. When washover occurred on the natural shingle beach the effect was to form tongue-like lobes of gravel sloping towards the marshes. This type of washover is a characteristic of the Chesil Beach. The artificial gravel ridge behaves differently. Because it is like sedimentary strata, it is eroded as is Quarternary strata. Small channels or gulleys are developed and water flows down these and deposits a fan of gravel at the base. This is only seen, so far, on a limited scale as a result of the St. Jude's Storm. See the photographs.
No firm conclusions are given here. Hurst Spit just remains under observation and we will see just what happens with future storms.
[Further note: At the end of Hurst Castle there has been further erosion. As noted elsewhere there has been some loss at the former jetty, which is returning to the sea. The Eastern Earth Batteries (old gun emplacements in brickwork and earth) have been significantly eroded. Bricks from these have been thrown back onto the beach adjacent to the end of the Victorian castle. Some erosion of the castle may take place in this area in a while.]
GENERAL INTRODUCTORY PHOTOGRAPHS
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INTRODUCTION:
Initial Comments
1.3 INTRODUCTION - Car Parking and Access
To commence a walk on Hurst Spit, you can drive to Milford-on-Sea; from the Green (centre) go south down Sea Road to the beach car park at SZ 293913. It is about 2 miles or 3 kilometres walk from here. This used to be difficult on loose shingle but because of sea-defence work this is now compacted and you walk to the castle comfortably in about an hour. You can walk back or return by ferry to Keyhaven (SZ 307914) and walk down the road from there (an easier journey). You could, of course, go to the castle by motor ferry from Keyhaven, should you wish (providing that the ferry is running at the time).
An alternative starting point is at Cut Bridge. This is at the end of the cut carrying water from Sturt Pond and the Danes Stream. It is at the junction of New Lane (turn into this in Milford-on-Sea village) and Seagrass Lane. You can often park in New Lane, and this is safely above high tide level. You may be able to leave a car at Saltgrass Lane that borders the marsh from Keyhaven to the shingle bank. However, this can flood at high tide or in stormy conditions.
You then start your walk at 299908 (Cut Bridge). From here it is about one and a half miles or just over 2 km to the castle. The disadvantage is that you will miss Sturt Pond and most of the big blocks of igneous rock-armour; however, you can back-track to these.
The New Lane, Cut Bridge locality is not a suitable route for a coach or bus. If you are travelling by coach then you need to make arrangements to be dropped at Milford-on-Sea.
There are toilets at Milford-on-Sea and at Keyhaven. At the castle end of the spit toilets are only present within the castle and you have to pay to enter this monument. Refreshments can be obtained within the castle, at least in summer. There is a pub at Keyhaven, the Gun Inn, and at the Green in Milford.
Hurst Spit is a barrier beach, the southeastern aggradation feature to which the subangular flint beach shingle of Christchurch Bay has been moved progressively eastward by the longshore drift (compare to the Chesil Beach). This transport from west to east is the result of the prevailing southwesterly winds. The spit represents the destination for subangular flint gravel travelling by long-shore drift from the supply cliffs of Highcliffe, Barton-on-Sea and Hordle Cliff. The light brown, flint gravel is present in most of the cliffs as a 2 or 3 m thick (exceptionally more) unconformable cap of Pleistocene periglacial clastics, overlying Eocene sands and clays. Not only is gravel on the spit, but also pieces of shelly siderite from Barton-on-Sea and fossils from the Barton Clay, particularly the gastropod Clavilithes. This has long been noticed and was referred to by Fox (1862) . You will not find it easily now because of the renourishment or replenishment of shingle.
Gravel has always been lost from the end of the spit and the whole spit has moved landwards by a "rollover" process. It has survived more or less unbroken for thousands of years, but not in the same place . Washover and temporary breaching has occurred recently because the delayed effects of the sea-defence works in Christchurch Bay finally stopped any significant natural transport of shingle to the beach. There was a crisis in 1989 when the shingle beach was flattened and at risk of total destruction.
To deal with this human intervention has taken place and the spit has been largely rebuilt with dredged gravel from the Shingles Bank. It is peroidically replenished with similar flint gravel. The long stretch is now banked up to 7m in height. This artificial banks suffered some damage some minor washover in the St. Jude's storm of 27th-28th October 2013, but has not yet been attacked by a real hurricane. It does not have its orginal natural appearance of Hurst Spit and is more like a railway embankment. It is composed compacted gravel and sand and has a flat top so when necessary vehicles can drive down it. Nevertheless it still exists and to the casual observer may look fairly natural. The far end has been less affected by erosion and has not been rebuilt and renourished. Much of the recurved end of the spit is still in natural condition and its accretionary development can still be studied.
It is interesting in that both construction of the castle and of the sea defences have resulted in the introduction of hard igneous rocks to the area. There is granite from Cornwall in the Castle Walls and bluish-grey, coarsely crystalline larvikite from Norway at the sea defences of the western end. There are a number of other interesting rock types present in the Castle walls, including Purbeck Stone and Bembridge Limestone from the Isle of Wight.
Of course coastal erosion problems are a characteristic feature of Christchurch Bay. Is a relatively new bay, famous for coastal retreat, especially at Barton and Highcliffe. Nearer to Hurst Spit, At Milford-on-Sea, the natural overall retreat of the coast must have caused some concern at Milford-on-Sea in the 1950s. Unfortunately, at about that time some defences were constructed there (as indicated by old photographs). The sea-defences have been strengthened since (see the Hordle Cliff webpage ) and now it is very difficult for shingle to pass eastward of Milford beach.
The rock armour barrier at the landward end of Hurst Castle Spit is a more recent development which although apparently giving some protection to land behind the beach is yet another barrier to the transport of any remaining shingle transport eastward.
A consequence of the development of the coast of Christchurch Bay over the years and the human efforts to stop cliff erosion and loss of beach at places to the west was a dwindling of the quantity of shingle on Hurst Castle Spit. In February 1979, as shown in the photograph, the sea almost breached the beach directly east of the sea-defences and the beach ridge was stepped back out of line. There was fear that if nothing was done the shingle ridge might permanently breach, letting large waves into the West Solent and isolating the Castle area of the spit as an island. Bulldozers were quickly brought in and the shingle beach was repaired.
What happened in 1979 was a precursor of the much more serious damage of 1989, discussed in some detail below. It was the storms of that later period that caused extensive flattening of the beach, and threat of its loss.
The coastal protection work on Hurst Spit followed and a good account of them has been given by Wright (1998). This useful article provides information on dates and quantities of gravel involved and costs.
INTRODUCTION:
General Setting in the Local Sea Area
Hurst Castle Spit, at entrance to the West Solent, is easily found on a map of Hampshire. It is south of the New Forest, marks the eastern end of Christchurch Bay and is almost north of the western extremity of the Isle of Wight. An old map, below, shows the spit in its natural condition in 1935, before it was effectively destroyed by the action of sea defences at Barton-on-Sea and at Milford-on-Sea cutting off the natural supply of flint shingle from the cliffs of Christchurch Bay.
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INTRODUCTION:
Maps - Historical
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INTRODUCTION:
Maps - Geological
Compare the aerial photograph from about 2005 to the old map (1930s?) above of Hurst Spit and Hurst Castle area. Notice that not only is the shingle beach much reduced but that the saltmarshes and mudflats have been cut back severely. About half of Hawkers Lake and adjacent marshes have been lost in the region north of North Point.
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The aerial photographs above are partly from old sources, but mostly courtesy of and copyright of the The Channel Coastal Observatory , National Oceanography Centre, Southampton. Many more aerial photographs are available from the CCO. For Hurst Spit and Keyhaven Marshes there are many ortho-rectified aerial photographs from the 10th September 2001 and from the 18th August 2005. Much other data is available, including Lidar etc. The photographs shown here are only examples to give a taste of the type of data than can be accessed, and to bring out some major points about the area. The beaches of Hurst Spit are being eroded, but they have sea defences. Careful study of the aerial photographs of the beach is recommended.
Also shown are aerial photographs of the Keyhaven saltmarshes and mudflats. The saltmarshes are in decline and they are returning to mudflats (as they once were). However, they will not be exactly the same as prior to the growth of Spartina (about 1895 onwards). Rising sea-level and the resulting coastal squeeze is likely to severely decrease the intertidal area at the back of Hurst Spit and near Keyhaven. It is well-known, of course, that Spartina saltmarsh decline and erosion is a major aspect of Pennington and Lymington saltmarshes further to the northeast, and also the Beaulieu River Estuary. It is general, in fact, for the Solent area. The mudflats will become the main feature behind the bank of Hurst Spit at very low tide. However, with higher sea levels, they will be much smaller, more easily flooded and less extensive as sources of food for birds.
The aerial photographs should be examined again in relation to specific sections on particular topics in lower parts of this webpage.
[Exercise for students:
Examine the above aerial photographs of Hurst Spit and Hurst Castle. One major objective is to protect the castle, both Henry VIII's and the Victorian extensions. Consider the factors of rising sea-level and storm action from the southwest. Dominant longshore drift on the main bank is from west (or northwest) to east (or southeast). Note, however, that near the castle there is also major current activity that can move pebbles. In addition, longshore drift may be in different directions within the West Solent part of the spit (i.e. east and north of the castle). Which parts of the beaches, shown in the aerial photographs, are at greatest threat with regard to the long-term survival of Hurst Castle? Can you recommend new measures to reduce the problems?]
The Beach Shingle
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Hurst Spit was originally a barrier beach of loose flint pebbles, which had been eroded from the cliffs of Highcliffe, Barton-on-Sea, Hordle Cliff and Milford. This natural supply was cut off by various sea-defences along this stetch of coast. Eventually Hurst Spit became so weakened that it was danger of being permanently breached.
To deal with this problem sea defences at Hurst Spit have gradually been increased, with a major development having taken place from 1996 to 1997 after a serious storm. The larvikite rock armour discussed below, was put in place at the western end and near the castle. 300,000 cubic metres of shingle from the Shingles Bank was added to the beach and much of this can now been seen as a different layer of material at the beach crest. This dredged shingle is very sandy and poorly sorted. Some of the flints within it have encrustations of serpulid worms, which makes this material distinguishable from the typical beach pebbles. The latter, at least high on the bank, are loose, cleaner and mostly free of sand.
The top artificial layer can compact and become fairly firm because of the sand content, and probably the poor sorting. It makes a relatively easy surface for walking, compared to the natural shingle, and will also take 4 by 4 vehicles. This clearly must have some advantages, especially to the staff of the castle, but it has to some extent changed the more remote, island-like character of the end of the spit and Hurst Castle. It is just half-an-hour's easy walk now (you can also travel there by boat).
In spite of the sea defence work some erosion is taking place and, as shown in the photograph, the artificial gravel has been cut into by a small cliff on the seaward. Presumably only rare storms produce waves which reach this high part of the beach.
BEACH MATERIALS:
Hurst Castle Bitumen
The manor of Hordle passed to Thomas Legh of Cheshire in 1832 ( James ,1986). He owned coal mining interests in Lancashire. He claimed that the beach "abounds with a mineral from which Asphalt is manufactured". James (1986) quoted the noted wildfowler Colonel Peter Hawker (whose house was adjacent to the Gunn Inn, Keyhaven) who was interested in this apparent occurrence of hydrocarbons. He noted in his diary in August, 1839:
By 1840 there was a factory constructed for the processing of the "Bastenne Bitumen" and it is figured by James (1986).
Hurst Castle Spit is now in rather unnatural condition with much gravel that has been tipped there to form a sea-defence. There are places, though, that are still in fairly natural condition. Thus, if you examine the natural part of beach of the southeastern end Hurst Castle Spit at about the high-water mark level, you will notice lumps of bitumen, pliant and sticky. You find them with other floating substances such as pine cones and light beach components such as the gastropod Crepidula fornicata. Of course such material at the present time could have come from oil tankers or other pollution. However, it could not have been of such origin in the 1830s, it is at the right place, it matches the description and adequately the explains the efforts of Legh to set up a small bitumen industry. There is also a perfectly reasonable explanation for its presence there by natural processes.
Major shingle beaches, in addition to aggrading pebbles by longshore drift, may accumulate floating substances. The photograph above shows pummice which is trapped on a long shingle beach in Cyprus. In a similar manner the Hurst Castle Spit which faces the prevailing southwesterly winds and waves may trap floating bitumen.
The spit is situated north-east of the English Channel Basin or Inversion, the source of oil for the great Wytch Farm oilfield of Dorset. On the Dorset coast and offshore there are hydrocarbon seeps. The small oil seep into the sea at Osmington Mills is one of the most well-known. Natural bitumen is present in small quantities in the Lulworth Cove area and at Durlston Bay and the finding of the Dorset hydrocarbon indications started the search for oil by D'Arcy Exploration Company in the 1930s.
More specifically Hurst Castle Spit is downwind of the well-known gas seep at Durlston Head, Swanage ( Hinchcliffe, 1978). If this methane seep also seeps oil then there is a nearby potential source of bitumen than can be transported by floating and blowing by the prevailing southwesterly winds. Durlston Head can be seen on a clear day from Hurst Castle Spit. However, this may be too simplistic an idea. There will, of course, be several unrecognised hydrocarbon seeps in the English Channel (oil) Basin or Inversion, and the Hurst Castle Spit bitumen may be derived from one or more of these.
The matter requires further investigation by organic geochemistry, but it is necessary to be careful that a modern samples taken may not be the original material but may be the consequences of pollution rather than a natural seep. If subsequent study, however, proves that the Hurst bitumen comes from an active local oil-seep then Mr Thomas Legh may have been the first person to use the hydrocarbons of the English Channel (Wytch Farm) Basin. The Romans and others have used the Kimmeridge oil-shale long ago in the past, but for ornaments or for fuel and actual oil was not otherwise used until recently.
[17 - temporary section - 17, to be moved]
4. BEACH MATERIALS:
4BF - Reworked Barton Fossils
The Reverent Fox in 1862 drew attention to the reworked Barton fossils which are present on Hurst Spit:
"at the western mouth of the Solent, there is almost an immeasurable accumulation of rolled flints, with which are mingled a sufficient sprinkling of fragmental fossill shells of various genera and species to show us from whence, the whole mass was originally transported This accumulation forms a sort of natural breakwater, two miles in length, one hundred yards in breadth, and many feet in thickness, extending between the mainland at Milford and a point beyond midchannel, where Hurst Castle was erected three centuries ago. Where the castle stands, this bank of flints becomes expanded so as to cover a circular space of fully twenty acres. Now all this enormous accumulation of flints, together with another one probably much larger on the island side of the main channel, and lying under the sea, in front of Alum Bay and the Needles, are formed of drift and broken fossils from the Barton beds ; the fossils themselves plainly pointing to the formation whence the whole mass was derived."
Until the spit was rebuilt as an artificial bank in 1989 Barton fossils could be found quite easily amongst the gravel. Occasional specimens might, perhaps, still be found because there is still natural gravel at the southeastern end of the spit. However, they are far from obvious now. Some selected specimens from my collection are illustrated above. See also the thesis of Nicholls (1985).
The spit material was originally mainly of subangular flint pebbles, with minor chert and other components. The flint pebbles have come from the Pleistocene gravels of Christchurch and it is not surprising that there is also a contribution from of clasts from the Eocene strata beneath them. Most of this consists of sands and clays that are easily distintegrated by the sea. There are few components that are at all resistant to abrasion on a shingle beach. They include some siderite, present as nodules in the Eocene deposits. Large, robust fossils could in the past have been washed out of the Barton Clay and then transported southeastward to Hurst Spit. The Barton Clay, unlike the Headon Hill Formation, includes a content of thick-shelled gastropods, mainly the common Clavilithes macrospira Cossman. There a few other large gastropods such as Hippochrenes amplus (rather rare) and Sycostoma pyrus (very abundant but not as robust as Clavilithes) and Athleta luctator (with other smaller species of Athleta).
The fossil material collected on Hurst Spit came mostly from just southeast of the Castle, but some was present on the main bank between Milford and the Castle. The total comprises 124 specimens. They can be grouped as follows:
Clavilithes - 58 specimens,
Mechanical abrasion of the reworked gastropods collected at Hurst Spit appears to be more significant than solution. Therefore the original size and thickness of the shell of the genera recovered is probably the most important factor in survival of these carbonate clasts.
The reworked fossil gastropods were preferentially found with accumulations of modern gastropods (Buccinum, the Whelk) and other modern shells. These were concentrated along the beach crest, particularly at Hurst Point and along the active recurve (at the end). Being of low bulk density, and with various cavities, the aragonitic shells have been thrown up above most of the flint pebbles. Because of this there may not necessarily be large quantities of fossil shells beneath the beach surface.
At these two sites, Hurst Point and the recurve, the fossils were more common than on the beach at Barton-on-Sea or Highcliffe (with extensive sea defences they are rare there now). Hurst Point marks a major change in process from net erosion to the west to net deposition. The littoral drift of the shingle decreases by a factor of 10 and there is substantial offshore sediment movement (Nicholls, 1985).
The reworked gastropods have undoubtedly been derived from the cliff erosion or nearshore erosion of Barton Clay in Christchurch Bay. Prior to 1968 there was coastal erosion of about 200,000 cubic metres per annum of Barton Clay. Now, however, sea defences has reduced the area of cliff that can be eroded. Any transportable fossil material on the beaches now will have great difficulty passing groynes of rock armour and other barriers. Littoral drift of beach debris from Barton and Highcliffe to Hurst Spit has ceased, and this, of course, is why the spit can no longer reform after storm damage.
Considering Clavilithes alone, most of the specimens are imperfect when they are still in situ in the Barton Clay. Although not completely crushed or flattened, they may show some minor crushing and the anterior canal is sometimes broken. There is quite a large range of sizes in the cliffs. At Hurst Spit the size range is more restricted to larger forms because smaller specimens probably do not survive the abrasion of the journey.
It is not known whether the reworked fossil gastropods have been significantly transported onward offshore from Hurst Spit. Some might have been moved towards the Shingles Bank by the strong ebb current, which is capable of moving the finer flint shingle.
Sycostoma - 38 specimens,
Athleta - 27 specimens,
Hippochrenes amplus - 1 specimen.
SEA DEFENCES - ROCK ARMOUR
Larvikite Sea Defences (Larvik Rock Armour or Armourstone from Norway)
At the top is a photograph of a monolith of larvikite with a notice briefly explaining the origin of the larvikite rock armour sea defences at the Milford end of Hurst Spit. The second image shows the arrival of the larvikite. The monolith can be seen above the bridge at the southeastern end of the stretch of rock armour. The notice is rather damaged but it states as follows:
"Hurst Spit is a shifting shingle barrier beach protecting the western approach to the Solent. It also shelters large areas of saltmarsh and mud flats which are of value in themselves and provide much needed habitats for rare species.
The project has successfully balanced the varying and sometimes conflicting demands of conservation with the operational need to provide stability so that the Spit will continue to protect these important areas.
The contract was carried out between August 1997 and January 1997. It involved the transport by barge and placing of 124,000 tonnes of rock largely from Norway, and the placing of 300,000 cubic metres of shingle dredged from the Shingle Banks. Further placing of shingle is planned at intervals to replenish natural losses.
Client - New Forest District Council.
Consultant - Engineering Division New Forest District Council.
Contractors - Westminster Dredging Company Ltd.
with
Dean and Dyball Construction Ltd.,
ARC Marine Ltd.,
Stema Shipping (UK) Ltd."
SEA DEFENCE WORK - continued
4.1.1. Introduction to the Hurst Rock Armour
At the Milford end of Hurst Castle Spit, rock armour has been used quite extensively to protect the vulnerable area where the spit has almost broken through in the past. There has been some use of Portland Stone from the Isle of Portland, including cherty limestone and some Roach. There has been significant use of Carboniferous Limestone from the Mendip Hills, probably from Foster Yeoman Quarry near Shepton Mallet that has supplied stone to Barton-on-Sea for the same purpose. That at Barton has come from the Clifton Down Limestone. The larvikite is a relatively recent addition.
SEA DEFENCE WORK - continued
4.1.2 Introduction to Larvikite
Particular conspicuous is the coarsely crystalline, bluish grey, igneous rock - Larvikite. The rock was termed larvikite (or laurvigite) by Brogger in 1890 after the town Larvik, not far from Oslo. This is the most important Norwegian quarried stone and there are about 20 quarries in the area. It is at the coast of the Skagerrak and is easily shipped across the North Sea to the UK or elsewhere. See the webpage of Stema Shipping Armourstone, who export larvikite.
Larvikite is very coarsely crystalline, like granite, but bluish-grey and darker than granite. It is quite hard and has no significant porosity. It shows the special feature of a beautiful blue schillerization (sparkling crystals). When polished it is often used for banks, pubs, shopfronts and for kitchen worktops. The main components, the feldspar shows cleavages, or minute fractures in the large crystals. There are also some dark, almost black mineral components.
Larvikite has been used for rock armour at Lyme Regis, in Norfolk (Waxham to Happisburg) and elsewhere.
Larvikite is a plutonic igneous rock; it originated as molten magma which has been intruded at depth during Carboniferous to Permian times (about 300 million years ago and round about the same time as the Dartmoor Granite) into the Oslo Graben. This downfaulted trough is an aulacogen (or failed arm) due to the Permo-Triassic extensional tectonics that preceded the development of the Atlantic Ocean. In other words the region has been pulled apart by plate-tectonic forces but the process did not continue so as to create an ocean.
For detailed information on larvikite particularly see the website by A.O. Larsen - The Langesundsfjord site; the minerals from the Norwegian syenite pegmatites.
4.1.3 Larvikite - Introduction to Mineral Composition
In simple terms it is a rock of Intermediate composition - that is partway in chemical composition between granite (a light-coloured rock - an acid rock, high in quartz and light-coloured) and gabbro (a basic rock, dark-coloured rock - without quartz but with dark iron and magnesium minerals). The conspicuous blue-grey crystals with the obvious cleavage are of plagioclase feldspar, a aluminium silicate with sodium and/or calcium. These form the largest proportion of the rock. There are other crystals which in the field or the hand-specimen appear grey to almost black. The large size of the crystals is the result of slow cooling of the magma deep underground, as in the case of granite.
. 4.1.4 Larvikite - Further information
Classifying larvikite within the Intermediate plutonic rocks is not so simple. There are two reasons for this. Firstly the rocks vary in composition, and examination of the blocks at Hurst Spit will soon reveal how varied they are. Secondly the classification is dependent on the proportions of the different feldspars (a simple summary explanation of the of the feldspar family is given for reference below)
The key factor is the composition of the minerals of the feldspar family. These are rather complex in larvikite (because they show evidence of unmixing, that is separation of component, during cooling). This produces special crystals that cause the rock to be referred to as a perthite. This is an intergrowth of two minerals and has exsolution lamellae that result from the unmixing. The reflective gistening (schillerization) is a the peculiar reflection from the crystals (due to the presence of very thin exsolution lamellae). The blue colour is an interference effect.
. 4.1.5. Larvikite - Description
Larsen gave the following description of larvikite, which is given here, slightly modified and simplified:
Larvikite is a medium to coarse-grained rock, sometimes with mafic and accessory minerals in interstices between large feldspar laths (crystals of 1 cm or more in size). The larvikites commonly display an orientational fabric caused by the parallel or subparallel alignment of the often characteristically rhomb-shaped, feldpar crystals. The feldspar is unmixed to a variety of perthite with a pronounced schillerizing (glisterning) effect. It is this which makes the rock an important ornamental and building stone. Larvikite also contains small quantities of other minerals, such as quartz or nepheline, plus or minus olivine ..
4.1.5 Larvikite - Thin-Section Petrography
We will now examine a thin-section. This is in PPL, plane polarised light, after Hatch, Wells and Wells (1949) is provided above, but note that the colours shown are added and are schematic rather than accurate. Note that because larvikite varies greatly this is not necessarily typical.
The mafic minerals are very distinctive in thin section and occur in clots. Hatch, Wells and Wells (1949) commented that are more what would be expected in a basic rock like gabbro, rather than in this intermediate rock, for they include olivine, and purplish augite, strongly schillerized and irregularly rimmed with the bluish-to-green amphibole barkevikite. Lepidomelane, an iron-rich biotite moulds itself on irregular masses of opaque iron ore, magnetite. Apatite is a constant accessory in unusually large crystals, often euhedral, and this is obvious in the thin-section.
.
4.1.8 Larkivite - A Very Coarse-Grained, Igneous Rock
COAST EROSION AND RECESSION - ROCK ARMOUR
4.1.9 Carboniferous Limestone Rock Armour.
There is a limited amount of Carboniferous Limestone rock armour, towards the southeastern end of the larvikite rock armour. There are some unusual rock types present in this Carboniferous material. One, shown above, contains flaser bedding and abundant reworked crinoid ossicles and also, surprisingly, some calcite replacements of gypsum or anhydrite nodules. Such nodules occur here and there in Carboniferous Limestone, but it is unusual to see them in a high-energy, flaser-bedded facies.
There is a low-energy, marshy coast from Keyhaven Marshes, through Pennington Marshes, past Lymington, the Pylewell Point, Sowley and the beginning of the Thorns Beach area. This is anomalous for the open Solent. Such low marshy coasts occur on the sheltered, western side of Southampton Water, and in the very restricted estuaries of Portsmouth Harbour, Langstone Harbour and Chichester Harbour. The southern part of the West Solent has cliffs of Tertiary strata in places but marshes are not developed except in creeks. The eastern Solent and Spithead coasts are subjected to significant wave action and have pebble beaches and spits and some low eroded cliffs (particularly in Bracklesham Bay and at Brownwich and Chilling near Lee-on-the-Solent). Thus the Lymington area is anomalous. It owes its special quiet, low-energy character to protection given by Hurst Spit. Sea-level is slowly rising and there is gradual loss of marshes by die-back of Spartina and by erosion. Thus the Lymington coastal area will slowly become a place of shingle beaches and low cliffs, with significant wave energy. If Hurst Spit is breached and partially destroyed, then the increase in erosion and cliff-devlopment in the Lymington area will be rapid as sea-waves gain access to the previously protected area. In turn, this will provide shingle that will travel eastward by longshore drift, eventually blocking or partially blocking the Beaulieu Estuary (which will close up like Titchfield Haven, a former estuary). Shingle spit development at Lymington can only happen if Hurst Spit is destroyed and its shingle transported north-east to Lymington. This could happen, but it is obvious that the Beaulieu Estuary is under greater threat, and in any case, it has already had substantial shingle transport towards the Needs Ore Point area.
Sturt Pond is the flooded lowermost part of the valley of the Danes Stream, at Milford-on-Sea. The shingle spit has blocked its original exit to the south; an artificial channel has thus been cut through to the southeast so as to link it with Mounts Lake, a channel in the Keyhaven Marshes behind the spit. In the landward end of Mounts Lake (near the Sturt Pond outflow) at low tide you will probably see the Asian and African member of the Heron family, the Little Egret (Egretta garzetta) which is now very common in the "globally-warmed" water of the Solent and other south of England estuaries. With it are Turnstones, Plovers, and Redshanks etc. The Keyhaven Marshes are popular amongst bird-watchers.
The artificial channel cuts through a low-level Pleistocene gravel terrace with brickearth on top. It is mainly the brickearth which is exposed in the banks of the channel. The gravel, which is believed to lie beneath has a top surface quite close to sea level. This is the Pennington Gravel of Allen and Gibbard (1994). It has been investigated from borehole samples from the Pennington Marshes Allen et al. (1996). The boreholes show a Pennington Upper and Lower Gravel. The upper gravel, presumably the one under the cultivated fields northwest of Keyhaven Marshes is probably Devensian.
5. LOCATIONS continued -
5.2 Beach at Western End of Hurst Castle
Another area of erosion is at the western end of Hurst Castle, that is at the western end of the West Wing. Here there are groynes and larvikite and limestone rock armour. There are erosional problems here in spite of this.
In the winter of 1999-2000 there was some exposure of peat beneath the beach gravel at the western end of the West Wing, adjacent to the rock armour and brickwork relics. Erosion and retreat of the spit in a landward direction had exposed peat with wood remains. For more information on peat at Hurst Castle Spit see Nicholls and Clarke (1986) .
LOCATIONS continued -
Hurst Point
(southeastern end of spit, beyond Hurst Castle)
Hurst Point is the southeastern end of Hurst Spit, that is in the area of the lighthouse, just beyond the castle. It is not the northern tip of the final recurved spit; that is North Point or Point of the Deep. It is easily accessible, either by walking down the artificial shingle bank and proceeding beyond the castle, or by taking the ferry from Keyhaven. Usually the ferry lands in an inlet from the harbour directly north of the castle, but if the tide is very low it sometimes lands at Hurst Point, as shown in a photograph above.
Hurst Point - Accretion in 1960-1980s?
Hurst Point, the eastern part, is an interesting area of accretion of shingle, and thus greatly contrasts with the erosional areas of the main Hurst Beach. This promontory has extended out so that the former military jetty, intended for shipping in ammunition, is now entirely on dry land. This accretion must have occurred before the present phase of limited shingle transport on the outer (southwest) side of the castle, where now there are groynes, rock armour and very little shingle transport.
On the 20th April 2007, I spoke to the captain of the small ferry from Keyhaven to Hurst Castle about the jetty. He told me that more than 40 years ago in 1963 he had managed to bring a medium-sized boat into this jetty before the major phase of shingle accretion. It was only just possible then and it was done with something of a bump on the shingle. He decided at the time this was the last chance to use this jetty. After that the beach built out beyond it.
Hurst Point - Erosion at the Southeast Corner
In spite of the accretion, aggradation or progradation at Hurst Point near the lighthouse since the Second World War, there is now a phase of erosion taking place at the southeastern corner, near the East Wing of Hurst Castle. The erosion and partial destruction of the mud batteries of the 1850s to the southeast of the East Wing of the Castle is very conspicuous (See James (1986) for more information on the mud batteries)
LOCATIONS continued -
The Easternmost and Final Recurve of the Spit
LOCATIONS continued -
North Point (Point of the Deep)
North Point or Point of the Deep is at the end of the final recurve of Hurst Spit. Medium-sized shingle is moved northward by the smaller waves of the Solent and effectively tipped off the end of the spit here. After a stable phase from 1742 rapid accretion commenced at the Point of the Deep or North Point in 1908 and continued to the present ( (Nicholls and Webber, 1987a) A black lookout hut that was once on the end of the spit is now well back from the termination.
This is a relatively undisturbed area and good for bird life. Terns are summer visitors to the area and live in this North Point area. They can be seen plummeting into the water for fish from the southern end of Hurst Castle or the adjacent beach next to the lighthouse. Sandwich and Common Terns nest on the saltmarshes, while the Little Tern nests close to the high tide line on the outer undisturbed shingle banks.
LOCATIONS continued -
Keyhaven Marshes (the Saltmarshes)
Cut Bridge is the small wooden footbridge across the Cut which carries water from Sturt Pond to the Keyhaven Marshes. It is at the eastern end of the main larvikite sea defences. At low tide this is a place for seabirds. The activity seems to be a relatively recent introduction in this area.
A large proportion of original mudflats behind the spit were colonised many years ago by Spartina anglica to form saltmarshes. This plant arrived in 1895 (Wright, 1998) and has since flourished; it has trapped mud and raised the level of the marshes. At the time of writing (2006) it does not seem to much affected by die-back as it is at the mouth of the Beaulieu Estuary. Wright mentioned that the raised marsh has been trapped beneath the spit as it rolls over landwards. Relics of this can be seen in favourable low tide conditions at the seaward side of the shingle spit. Apparently the raised marsh beneath has had some effect on raising the crest level of the spit, until there was loss of volume in the 1960s.
On the low washover gravel at the back of the Spit the Sea Purslane Halimione portaculoides grows with some other halophytes.
The small modern gastropod Hydrobia ulvae (the Laver Spire Snail) grazes on algae at the mud surface when the tide is in. When the tide goes out it burrows into the mud. It can reach densities of 20,000 to 80,000 gastropods per square metre of mud (Hampshire County Council, 1984). It is an important part of the diet of Shelduck and fish. Large numbers of the shells of this gastropod are washed up on the harbour side of Hurst Beach, especially in the lagoons between recurves near Hurst Castle. Hydrobia is common in ancient lagoonal sediments like those of the Purbeck Formation, and is also used in the study of Pleistocene interglacial estuarine deposits (West, R.G. and Sparks, 1960).
LOCATIONS continued -
The Shingles Bank
The photographs above seem to show the Shingles Bank, a well-known bank of subangular flint shingle, that lies between Hurst Spit and the Needles. It is near low tide level and may be exposed from time to time. However, according to the Milford-on-Sea News this island is the Dolphin Bank (a bank which commences 3 km west of the Needles) and not the Shingles Bank. However, its orientation when seen from central Barton-on-Sea and from Milford-on-Sea seems to indicate that it is part of the Shingles Bank. From the eastern cliff top car park at Milford it almost aligns with Headon Hill on the Isle of Wight. From Barton on Sea it appears northeast of the Needles, not to the west of the Needles, as can be seen in a photograph above. This is not compatible with the position of the Dolphin Bank. The article mentioned that it was, in November 2010, 400 metres in length, with a further 800 metres identifiable by waves breaking on the bank where it is just below sea-level.
The Shingles are a shallow bank of subangular flint gravel. They have provided ballast of shingle for small vessels in the past. This large shoal area appears to have moved eastward and increased in size according to Nicholls and Webber (1987b). They commented that is somewhat contrary to the recollections of the older inhabitants of Milford-on-Sea who remember larger drying areas on the Shingles Bank at low water of spring tides than occur at present. However, a decline in the drying area is not necessarily inconsistent with the chart study of these authors as the chart also considers changes beneath low water. On balance they considered that the Shingles Bank was showing increased stability in years prior to that publication, rather than increased erosion. They, thus, thought that increased erosion of the Shingles Bank was not a cause of the recent increased erosion on Hurst Spit.
White (1915) put forward a theory of transport of material from Hurst Spit. He also mentioned a small island on the Shingles Bank: "At ebb tide a strong current sets out of the Solent through the Needles Channel south and south-west of Hurst Castle. It is inferred that much of the coarse waste from the cliffs of Christchurch Bay, carried eastward by shore-drift, is caught by this current at the head of Hurst Castle spit, and thrown out of the Needles Channel westward to form the extensive shoals and small whale-backed island of The Shingles (fig. 15), north of Totland Bay."
As mentioned elsewhere in this webpage there was a scheme of strengthening Hurst Spit between August 1996 and January 1997 by doubling its volume. This involved building up its landward side and raising the crest height by an average of 13 metres. The Shingles Bank was estimated to offer the most satisfactory shingle size grading at an economical price according to Wright (1998). This author wrote:
"There are advantages and disadvantages associated with each, but the Shingles Bank source was estimated to offer the most satisfactory shingle size grading at an economical price. The Shingles Bank lies in very shallow water close to the New Forest and Isle ofWight shorelines and would not normally be licensed for commercial aggregate extraction. However, consultations with the licensing authority, the Crown Estate, led to an agreement that a dredging licence application from New Forest District Council would be considered if the material was used solely for rebuilding
Hurst Spit, and no detrimental effect on the Isle of Wight shoreline, or on the long term stability of the Bank itself, could be demonstrated. Following extensive computer modelling of wave data and wave refraction patterns in Christchurch Bay, and the completion of an in-depth environmental impact assessment, it was shown that these conditions could be met and an application for a dredging licence was made. After much delay this was approved."
This could mean that gravel and other sediment from the Shingles Bank, that is normally inaccessible, is visible on Hurst Spit. Of course it is a long time since the material was added and there is a risk that recently transported debris from elsewhere on the beach might be mixed with Shingles Bank material.
Because the dredged shingle was pumped onto the bank, it is unlikely that large pebbles would be present. Probably most of the material is difficult to distinguish from the original natural shingle of Hurst Spit.
[There is some peculiar material at the highest part of Hurst Spit. It can be seen, well-exposed, in a small cliff at the top of the beach. This might be from the Shingles Bank, but some of it perhaps it is too coarse. I hope to find out about the source of this later. Some pebbles were found at the foot of the little cliff with serpulid worms or calcareous encrustations that have originated below sea-level. However, it is not confirmed that this material on the top surface of the Hurst Spit is actually from the Shingles Bank. It is possible that it is something of different origin placed there to form a suitable surface to support vehicles.
This top material is less well-sorted than the natural beach material and includes larger clasts. In general the top gravel, is fairly typical of the local Pleistocene terrace gravel and beach gravel which has been reworked from it. It consists largely of brown subangular flint pebbles. There are many that have been whitened in a podzol soil profile. These are normally found at the top of the Pleistocene gravels in the cliffs of Christchurch Bay. A little iron-cemented sandstone is not unusual. This is formed in iron-pans, usually near the base of the gravels, and similar material can be seen in the cliffs of Barton-on-Sea. There is surprisingly little carbonate material and the gravels seem to have been leached to some extent. No shells from the Eocene of the Barton cliffs were noticed in a brief search.
One slab of sarsen stone was found. This has good root moulds running through it; it may not necessarily have come from the topmost gravel. It could be naturally-transported beach material of other origin. The quantity of sand in the top gravel is surprising. It is much more sandy than the natural shingle of the bank of Hurst Spit. The sand is white, coarse and with much vein quartz. It does not seem to be very glauconitic as might have been expected (with glauconitic clay and sand sources in the Barton Group).
In general the top gravel could have originated from longshore drift transport in Christchurch Bay. It seems coarser and more poorly sorted, however, than the natural shingle of Hurst Spit. It contains some large, rounded flint pebbles which may have ultimately originated in the top Boscombe Sands pebble beds.
Hurst Castle is well-worth visiting. It is because of the existence of the castle this particular shingle spit has a recorded history going back to about 1540, and there various old maps and etchings. The castle is significant in terms of coastal processes development in that it has provided a fixed and recorded point. The castle has remained in place while the shingle spit which has been subject to erosion in some parts and aggradation or progradation in others.
There is much detailed information on the history of the castle which you will find in the publications of James (1986) (a very detailed account, full of valuable information) and Coad (1990 and later reprints).
Obviously, the history of human activity on the spit is useful in understanding natural changes. There is an early record for Hurst Castle Spit is that of six salinae or salt pans in the manor of Hordle. These were almost certainly on the protected side of the shingle spit, and indeed later maps show salt pans behind the spit ( James, 1986). Later records are in relation to the castle. The King's warrant for the erection of fortifications at Hurst was dated 1541. From then onwards there is historical information from time to time.
One aspect of the history of the castle is of particular geomorphological interest. If you examine some of the various old maps and etchings, as shown in James' book ( James (1986) it is clear that the old stone castle was situated at what was then the end of the spit. The similar castle at Calshot Spit remains in such a distal position today. At Hurst, however, the beach has extended quite dramatically. The shingle has built on eastward beyond the original castle now. When the fortress was extended much later, in Victorian times, the East Wing was constructed on this new post-1540s extension.
The castle is now discussed briefly. It can be considered simply in terms of two main components. The old Tudor Castle is a grey building of limestone in the centre. Most of this interesting old building can be visited, but note that it has been strengthened by internal brick vaulting in Victorian times so as to be able to carry heavier guns. Photographs of the old part are shown below.
The other and large component is the Victorian addition. This consists of an East Wing and a West Wing with internal brick walls and external armour of limestone on the landward side and granite on the outer side. The West Wing is open to tourists at certain times, but the East Wing is not. More photographs of these Victorian wings are provided further down the webpage.
Walking down the long spit of shingle with a compacted gravel top, you approach the Castle by first encountering the outer walls of the Victorian West Wing. You can see the strong granite walls on the seaward side with less resistant limestone blocks, much of it Purbeck and Portland stone, on the harbour side. A signpost directs you to the castle entrance at the back, harbour side. You will see the old stone, Tudor building, which was the original castle, within the extended Victorian fort.
HURST CASTLE continued -
Hurst Castle - Adjacent Lighthouse
6.2 LOCATIONS - HURST CASTLE continued -
King Charles I
The old castle is notable for having been a place of imprisonment, albeit briefly, of a King of England. We will divert for a few minutes to consider this non-geological topic!
In 1648 King Charles I was arrested at Carisbrooke Castle on the Isle of Wight where he had been staying.
On the orders of Oliver Cromwell he was taken away by Lieutenant Colonel Cobbett in a coach and, accompanied by some servants, transported across the Solent to Hurst Castle. He was imprisoned for three weeks in this isolated castle. He seems to have lived on the first floor and was not excessively restricted. He was allowed to walk on the spit at times and view the shipping. James (1986) gives a very full an interesting account of this in his Chapter 2 - The Civil War and a King's Prison, and this well-worth reading. Here is the account of his arrival at Hurst Castle.
"The Coach, by the Lieutenant-Colonel's Directions, went Westwards towards Worsley-Tower, a little beyond Yarmouth-Haven. Thereabout his Majesty rested until the Vessel was ready to take him aboard with those few [of] his Attendants. The King, after an Hour's stay, went aboard a sorrowful Spectacle and a great Example of Fortune's Inconstancy. The Wind and Tide favouring they crossed the narrow sea in [three-quarters of an hour] and landed at Hurst-Castle . . . The Captain of this wretched place was not unsuitable, for at the King's going ashore he stood ready to receive him with small Observance. His look was stern, his Hair and large Beard were black and bushy, he held a [long-handled spear] in his Hand and, Switz-like, had a great Basket-hilt Sword by his side. Hardly could one see a Man of a more grim Aspect and no less robust and rude was his behaviour. Some of his Majesty's Servants were not a little fearful of him. . . especially when he vapour'd, being elated with his Command and puff'd up by having so Royal a Prisoner, so he probably conceived he was nothing inferior to the Governour of the Castle of Milan. . .
His Majesty was very slenderly accommodated at this place. The room he ate in was neither large nor lightsome, at Noon-day in that Winter Season, requiring Candles. At Night he had his Wax Lamp set, as formerly, in a Silver Bason which illuminated his Bed-Chamber."
After only about a fortnight at Hurst Castle the King was alarmed when Major Harrison arrived with his horsemen at night at the drawbridge (you can see it in the picture above). This arrival was in preparation for his removal, which proved to be a route to his execution.
On the 19th December 1648 a convoy of Horse and Dragoons transported the King from Hurst Castle to Windsor Castle. Little more than a month later, on the 27 January 1649 King Charles I was beheaded on a scaffold outside the Banqueting House in Whitehall, London.
(James, 1986, p. 32)
HURST CASTLE continued -
Entering the Castle
Now from the path on the north side of the buildings we can enter Hurst Castle. Inside, you can visit the old Tudor building, in addition to the later Victorian extensions with large guns, the historic exhibits and a view of the spit from the roof. There is a small charge which might vary from that shown here on the 2005 notice board. At the small office you can purchase guide books and postcards. There is a cafe and toilets (restrooms) inside the castle walls. The castle is usually open in the summer. Should it be closed there is still much of interest to see on the outside of it, and your walk will not be wasted effort.
Here is the main notice. It shows the Tudor castle at the very end of the spit before the Victorian constructions. The original entrance on the far right (western side) is now within the Victorian outer wall and we shall get to that shortly.
We go over the little drawbridge (a later, Victorian one, not the original), with the steel lines of the narrow-gauge ammunition railway or tramway. We pay the warden at a door on the right, and then if we chose to visit the old castle first we turn left just inside the main entrance. .
Here is the old doorway that leads in. This was the original entrance to the Tudor Castle and here there was the drawbridge over the original moat that has since been filled in. This was the drawbridge referred to by King Charles. His quarters were on the First Floor, accessible now by the steps shown in the middle picture.
Within the courtyard of the old castle, beteen the northwest bastion and the central tower, examine the limestone of which the building is constructed. The brickwork is, in general, an addition of Victorian times to strenthen the castle for use of heavy guns.
You will notice the use in the walls of Purbeck Stone and Bembridge Limestone from the uppermost Eocene of the Isle of Wight. The Bembridge Limestone is distinctive because it has conspicuous, mouldic secondary porosity. That is to say that the aragonitic shells of gastropods, such as Galba longiscata and Viviparus have been dissolved away, leaving easily recognised, corkscrew moulds. Purbeck limestone varies in detail, but generally it is very shelly with small sub-parallel shells. These are compacted, small bivalve shells ( Neomiodon etc.) and give a broadly laminated appearance. Purbeck limestone is harder and does not show the same type of mouldic secondary porosity (although, of course, some beds do contain Viviparus). Charophyte oogonia are visible with a hand-lens in some blocks of the relatively soft Bembridge Limestone as small spherical objects with spiral markings. Although these also occur in low-salinity Purbeck limestones they are rarely seen in Purbeck building stone. Thus most, but not all, samples of Bembridge Limestone (Binstead Stone) are quite easily recognised. As shown above there seems to be some heathstone or Burley Rock used on a very small scale, but it is high in the wall and has not been checked in detail.
In the time of King Henry VIII Bembridge Limestone may have been transported by sea direct from the Isle of Wight (it occurs just across the water), or from the destruction of Beaulieu Abbey, which was probably also largely built of this rock.
We can go down to the damp and musty basement. There is some lighting now, but it is still quite dark. About 50 years ago when I was a boy I used to go down here before there was any electric lighting. It was fun to pick up a paraffin huricane lamp to find a way down into the gloom of this basement of the keep, which we wrongly imagined was the "dungeon". It is still an interesting and curious place; you can wander round this sort of dark circular tunnel, wet and near sea-level and with no windows. Round a corner you will find barrels representing the ammunition that was once stored here (there is a "dungeons and dragons" feel to the place!).
HURST CASTLE continued -
The Victorian Wings
Mud batteries, gun emplacements protected by banks of mud, were constructed east and west of the old castle in 1853. Work started in 1861 on the foundations for two large permanent wings, either side of the castle (James, 1986). Building of the superstructure commenced in 1863 by G. Tyrell of Great Yarmouth and took seven years. In due course many R.M.L. (rifled muzzle loader) guns of 9 inch, 10 inch and 12.5 inch calibre were installed. Examples of these huge cannons are preserved.
HURST CASTLE continued
Cornish Granite of the Outer Castle Walls - Introduction and History
There has much use of Cornish granite in the extended Hurst Castle. This is same stone that has been used for the Fastnet Lighthouse off the southwest of Ireland and has also been used in Tower Bridge, London (see list of orders below). The granite has been placed so as to protect the casemates with their guns from enemy shells. This grey Cornish granite is from the quarries of John Freeman and Sons above Penrhyn near Falmouth (James, 1986). The massive blocks were shipped here and unloaded on the shore.
This particular granite is from the eastern side of the Carnmenellis boss of the granite batholith of southwest England. This great batholith trends west-southwest and comes to the surface as the bosses of Dartmoor, in the east, Bodmin Moor, St. Austell (Henbarrow), Carnmenellis, Land's End and the Scilly Isles. It is Permo-Carboniferous in age and a little less 300 million years old. It is a discordant batholithic intrusion into folded Devonian and Carboniferous strata, and formerly had volcanoes above. They have been eroded away but the debris of them still exists as the Exeter Volcanics.
Here is more information, from Hill and MacAlister (1906), regarding the granite quarried by Freeman and Co. near Penrhyn and used at Hurst Castle:
"The stone industry [of the Falmouth and Truro region].- This area furnishes a large proportion of the granite that forms the well-known Cornish granite industry, the rock being mainly raided from the Carnmenellis mass.
The headquarters of this industry is situated at Penryn, where the stone is dressed, and from which port it is shipped. The granite raised, however, in the more southern districts of Mabe and Constantine is shipped at Porthnavis. The stone is mainly wrought in a belt of country lying to the west of Penryn...
The granite is grey in colour, and its principal mineral constituents are felspar, quartz, and two micas, viz., muscovite and biotite, while tourmaline is commonly present as an accessory mineral. In texture there are two varieties, known commercially as "fine grit" and "coarse grit." The former, which usually occupies the outer belt for an average width of about a mile, although the superior stone, is not so extensively worked as the "coarse grit," on account of its being more expensive to dress. It is not only finer in texture, but is darker in colour, containing more biotite, and has a higher specific gravity (about 1 per cent). A good example of this stone is seen at the quarries at Carnsew, about one mile west of Penryn. The "coarse grit" is a more attractive stone, and is studded with porphyritic felspars that reach an inch or more in size, some of the most beautiful varieties of which occur in the parish of Mabe."
It is of interest to note some other places at which this Cornish granite was used. This list of dressed stones supplied by Messrs. J. Freeman and Co. is only for dock and harbour works, bridges and lighthouses
(Hill and MacAlister (1906))
DOCK AND HARBOUR WORKS.
BRIDGES
LIGHTHOUSE.
In addition a large part of the city of Truro was built from the stone. By 1906 the granite industry was undergoing a period of depression because of its inability to compete with Norway. The decline of the industry was being severely felt in the district of Penrhyn, where some of the skilled workers emigrated to America.
Gibraltar, 1899 to 1904 (large order - 1,250,000 cubic ft.)
Keyham, 1897 to 1905 (large order - 1,891,400 cubic feet)
Cardiff, 1899 to 1904
Portsmouth, 1894 to 1896
Folkestone, 1897 to 1904
Dover Harbour Board, 1892 to 1901.
Barry, 1892 to 1898
Kew, 1899 to 1902
Rutherglen, 1893 to 1895
Tower Bridge, 1887 to 1889
Fastnet, 1898 to 1902
6.6 HURST CASTLE continued
Cornish Granite of the Outer Castle Walls - Mineral Composition
In composition the Cornish granites are composed of feldpar, quartz and the two micas - biotite and muscovite. Obviously petographic study under the microscope is necessary for observing the details. In the field, as at Hurst Castle, only the major aspects can be seen by eye and with a hand-lens. The rock is to some extent porphyritic with moderate-sized laths of a white, translucent feldpar. This is probably orthoclase (a potassium feldspar) and, indeed, some simple twinning can just be seen in the photograph above. The abundant cleavage of the feldspar is obvious, but the details of this are not easily observed. There is, in some cases, some preferential orientation to the feldspar laths.
Next most conspicuous is the dark mica - biotite. With these black crystals there is white mica - muscovite, but this is very difficult to see without a microscope. The quartz is, as usual in granites, anhedral (xenotopic) and is visible as clear, glassy-looking grains. Cornish granites also contain plagioclase and micro-perthite (an intergrown feldspar) but you will not recognise these components in the field. Tourmaline, the boron silicate, can be a common component and there willl be other minerals that occur in the granites but would be very difficult to see on an exposed rock face. The Carnmenellis granite differs from some of the other southwest England granites in having feldspar phenocrysts of about 2.5 cm in length and smaller than those in the others.
Here is an aplite vein in the Carnmenellis Granite. This is a light coloured vein of quartz and feldspar. It generally lacks the mafic minerals. Such veins are products of late-stage fluids that were residual after most of the granite had crystallised. They are common in granites and can be white or pink and not necessarily thin like this. They can be metres thick.
The photograph above shows the typical, rather finer-grained type of Carnmenellis Granite with a interesting rosette of orthoclase feldspar and tourmaline (the black mineral, in this case, notable for containing boron - it is a complex borosilicate of aluminium, together with alkali metals or iron and magnesium). The boron content of the southwest England batholith is and interesting problem. One possible explanation is assimilation of boron-containing evaporites in the magma.
Footnote: Density of Granite.
Of course, the relative lightness of granite is well-known and is a major aspect of plate-tectonic theory (students - please explain this!). The low SG is because of the relatively deficiency of high-density mafic minerals (e.g. pyroxene). Quartz, feldpars, and mica have fairly low SGs - near 2.6 to 2.8. The overall SG of granite is close to that of a zero-porosity limestone (2.7).
If the SG is constant, then the factor which controls the bulk weight of a block of a fixed size, that is the bulk density, is the porosity. Many limestones, such as the Portland Stone, are quite porous and the pore spaces effectively reduce the overall weight and bulk density. The porosity of the Portland Stone is about 13 percent. It is almost entirely calcite, the SG of which is 2.7. Thus you can see that the bulk density of Portland Stone is about 2.3, whereas granite with no significant porosity (because it is of igneous origin) has a bulk density of about 2.7.
This is only one variable which we discuss now as a matter of passing interest; it is not the important factor here where the rock must be resistant to the impact of shells!
It is interesting to consider the bulk density and specific gravity of granite. A block of granite may seem heavy but, do not be misled, it is not, because the constituents have a high density. Ignoring porosity, granite is a relatively light rock. In fact the specific gravity of granite, 2.6 to 2.8, is almost the same as aluminium (2.6) and if its other properties were appropriate it would good for the construction of aeroplanes!
Earlier information about the Hurst Castle Prospect was given in 2006 by the UK Onshore Operators Group, (2006. OOG News and Press Releases. Re Hurst Castle Prospect).
"Offshore Licence P1153
P1153, located in the Wessex-Channel Basin also contains the Hurst Castle prospect which straddles the Hampshire coastline. The main reservoir objective is the Sherwood Sandstone with secondary potential in the Bridport Sandstone.
The offshore well 98/7-2 driilled by BP in 1987 is of particular significance regarding the prospectivity of this licence. 98/7-2 is situated approximately six kilometres from the southwest corner of Licence P1153 and encountered oil in the upper section of the Triassic Sherwood Sandstone. This well tested 1095 bopd of 43 degree API oil from the Sherwood Sandstone interval, the same reservoir as in the Wytch Farm field. This oil is lighter gravity than that at the Wytch Farm field which is 36 degree API.
The significance of this well is that it indicates that oil has migrated and is preserved east of the main hydrocarbon trap at Wytch Farm. This is believed to be the result of the basin configuration at the time of oil migration. Early formed structures of pre-Upper Cretaceous age such as that at Hurst Castle are potential traps for migrating oil."
A map and more recent information follows:
Part of the New Forest region near Lymington has been under investigation for petroleum resources by Wessex Exploration Ltd. Details can be found by going to their website at: Wessex Exploration Limited. (not necessarily available now).
Here is a small extract from the start of the webpage to draw attention to their work. Particularly see the good maps. Note the information on the Hurst Castle Prospect.
"Wessex Exploration Limited, bidding on its own in the 9th Landward Bid Round was awarded Petroleum Exploration and Development License (PEDL) 089 on 4 September, 2000. PEDL 089 is located in southern Hampshire near the towns of Lymington and New Milton, on the mainland opposite the western end of the Isle of Wight. The work obligation for the initial term of the PEDL was met when Northern Petroleum drilled the Bouldnor Copse 1 well, and fifty percent of the PEDL was relinquished in September, 2006. The PEDL is now in its second exploration period.
Wessex on 11 September, 2002 made an "Out of Round" application for a Petroleum Production License over the area immediately offshore from and adjacent to PEDL 089. Wessex was awarded License P1153 over this offshore area, effective 3 October, 2003. The primary term of this license expired in October, 2007, but was renewed by DBERR into a second exploration period.
A preliminary structural map of the Hurst Castle Prospect at the Sherwood Sandstone level is shown. Estimated P10 oil-in-place is of the order of 190 million barrels for the Sherwood reservoir alone, with possible recoverable reserve of 36 million barrels. A separate structural map shows four-way dip closure offshore, with possible P50 recoverable reserves in the 16 million barrel range." ... [continues].
See further details of the Hurst Castle Prospect.
They report that the Hurst Castle Prospect has potential recoverable reserves of the order of 36 million barrels from the Sherwood reservoir, in a Wytch Farm type fault-block feature. The primary reservoir is the Triassic Sherwood Sandstone. The Bridport Sands is a secondary objective as is the Frome Limestone (Great Oolite). In the same region an exploratory well was drilled at Boulder Copse across the West Solent on the Isle of Wight. The results were negative but Wessex Petroleum did not consider that this impacts on the prospectivity of the Hurst Castle objective.
Note that it is of interest regarding the New Forest National Park that the reservoir objectives are the same as those of Shell at Denny Inclosure (Lyndhurst - A).
[NEW SECTION - 3rd February 2018]
COASTAL HISTORIC PROCESSES.
ACKNOWLEDGEMENTS
I much appreciate the helpful discussion in the field with Robert Nicholls who has studied Hurst Castle Spit in great detail. I thank Barry Marsh for the photographs of the storm. I am grateful to the various students and members of my family who have worked with me on field trips or projects in this area. I thank the Open University Geological Society, Wessex Branch for field discussion and appearing in photographs. Very useful information has been kindly provided by New Forest history specialist Mr. J.J. Greenwood and I much appreciate his help. I am particularly obliged to the staff of the The Channel Coastal Observatory , National Oceanography Centre, Southampton, for kind permission to use their excellent aerial photographs. I thank the Custodian of Hurst Castle and the Ferry captain for helpful information regarding the history of the area. The helpful cooperation of the School of Ocean and Earth Science, Southampton University, is very much appreciated.
(See also Solent Geological Bibliography)
.
Allen, L.G. 1991. The Evolution of the Solent River System during the Pleistocene. Ph.D. Thesis, University of Cambridge.
Allen, L.G. and Gibbard, P.L. 1993. Pleistocene evolution of the Solent River of southern England. Quaternary Science Reviews, Elsevier, 12, 503-528. Authors are both from the Subdepartment of Quaternary Research, Botany School, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK. Abstract: The Solent River no longer exists since most of its course was drowned by eustatic sea level rise during the Flandrian Stage (Holocene). Previously, it flowed eastwards across southeast Dorset and south Hampshire as an extension of the River Frome. As such, it formed the axial major stream of the Hampshire Basin. A sequence of fluvial aggradations, ranging in height from 125 m O.D. to below sea level, provide evidence of the former courses of this substantial river and its tributaries. Detailed study of the deposits, supported by analysis of clast lithological assemblages provide the basis for the recognition of a series of lithostratigraphical units throughout the area. The facies and sedimentary structures indicate that the bulk of the deposits accumulated in a braided river environment under periglacial climates. Late Pleistocene fossiliferous sediments of Ipswichian and Flandrian age provide a biostratigraphical framework.The results demonstrate that the Solent River was a substantial system, comparable in size to the present Thames, and was a tributary ofthe 'Channel River' during periods of low sea level (cold stages). Evolution of the river reflects its response to climatic change, local geological structure and long term tectonic activity. Although datable deposits limit determination of the age of the Solent River sequence, it is undoubtedly of considerable antiquity and potentially extends back to the Early Pleistocene. Discussion of the sequence includes placing the events within their regional context. [End of abstract. - Notes: This is an important paper on the Pleistocene deposits of the southern Hampshire Basin. Many gravel terraces are recognised and named, but are not correlated in detail with the numbered terraces of the British Geological Survey (Southampton and Bournemouth sheets). The paper includes discussion of the following gravel terraces in the Bournemouth-Southampton area from lowest to highest: Pennington Gravel (Pennington near Lymington, and with Ipswichian Interglacial deposits); Lepe Lower Gravel (Lepe Beach, under the Interglacial deposit, pre-Ipswichian); North End Copse / Holdenhurst Gravel; Pennington Gravel / Burton Rough Gravel/ Southbourne Gravel; ; Lepe Upper Gravel (Lepe Beach, Devensian); Milford-on-Sea Gravel / Bransgore Gravel /Knighton Lodge Gravel; Stanswood Bay Gravel / West Southbourne Gravel / Taddiford Farm Gravel / High Cliff Gravel / Ensbury Park Gravel; Tom's Down Gravel (near Fawley); Old Milton Gravel; Mount Pleasant Gravel; Setley Plain Gravel (New Forest); Beaulieu Heath Gravel (New Forest); Tiptoe Gravel; Sway Gravel; Holmsley Ridge Gravel (western New Forest); Whitefield Hill Gravel. The Wareham-Dorchester Pleistocene gravels are also discussed. The paper includes interesting data on gravel composition, mostly flint and chert and including the presence of Portland Rhaxella chert and oolitic chert and Upper Greensand chert.]
Allen, L.G., Gibbard, P.L., Pettit, M.E., Preece, R.C. and Robinson, J.E. 1996. Late Pleistocene interglacial deposits at Pennington Marshes, Lymington, Hampshire, southern England. Proceedings of the Geologists' Association, London, vol. 107, pp. 39-50. By Lorraine G. Allen, Phillip L. Gibbard, Mary E. Pettit, Richard C. Preece and J. Eric Robinson (First three authors from the Subdepartment of Quaternary Research, Botany School, University of Cambridge; Preece from University Museum of Zoology, University of Cambridge and Robinson from Department of Geology, University College, London.). Abstract: Fossiliferous organic sediments interstratified within fluvial gravels at Pennington Marshes, Lymington, have been recovered in boreholes and investigated. The organic deposit, here defined as the Pennington Organic Bed, occurs between -3.9 to -5.3 m OD and has been traced 200 m across the immediate area. Pollen analyses indicate a temperate flora of interglacial character. Molluscan and ostracod assemblages contain no brackish elements and are typical of a shallow, freshwater stream or abandoned channel. A change from an aquatic to a terrestrial molluscan fauna indicates progressive drying out of the water body. The Pennington Organic Bed cannot be confidently attributed to any particular stage, but since it occurs within a lower terrace than that at Stone Point, 15 km to the NE, it is probably younger and an early Ipswichian age (Ip Ha?) is suggested. The Pennington Lower Gravel, below the organic deposit, is therefore probably Wolstonian and the Pennington Upper Gravel, above them, Devensian in age. The estuarine interglacial deposits at Stone Point, previously believed to have been Ipswichian, are likely to belong to an earlier stage. It is possible, although less likely, that they accumulated during a later part of the Ipswichian as the transgression aggraded to the level of the higher terrace surface. Similarly, if the gravels at Stone Point resulted from a tributary river, rather than the Solent River itself, this could also explain the altimetric differences and allow the organic deposits to be attributed to different parts of the same stage. However, there is no evidence to support either of these alternative possibilities.
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Barber, K.E. 1987, Wessex and the Isle of Wight - Field Guide. Quaternary Research Association, Cambridge. Prepared to accompany the Annual Field Meeting held at Southampton and Cowes, 21-25 April, 1987. 180 pp. paperback. Edited and compiled by Professor Keith Barber, Department of Geography, Southampton University. With 20 contributions mostly relevant to the Solent area, the New Forest and the Isle of Wight.
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Bird, E. 2000. Coastal Geomorphology: an Introduction. John Wiley and Sons Ltd., Chichester, 322 pp. [Hurst Castle Spit - pp. 163-164 with diagram.]
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Bray, M.J, Carter, D.J. and Hooke, J.M. 1995. Littoral cell definition and budgets for central southern England. Journal of Coastal Research, vol. 11, pp. 381-400.
(By Dr. Malcolm J. Bray, David J. Carter, and Janet M. Hooke, all three from the Department of Geography, University of Portsmouth, Portsmouth, PO1 3HE)(See also Hooke, Bray and Carter, 1996).
Bray, M.J., Hooke, J.M. and Carter, D.J. 2000. Sea level rise in the Solent region. Pp. 101-102 in: Collins, M. and Ansell, K. 2000. Solent Science - A Review. Elsevier, Amsterdam, 385pp. By M.I. Bray, I.M. Hooke and D.l Carter of the Department of Geography. University of Portsmouth, Buckingham Building, Lion Terrace, Portsmouth, PO1 3HE, U.K. [Extract:] Introduction: Sea-level has been a major factor in the evolution of the Solent Rapid post-glacial sealevel recovery, between 15,000 and 5,000 years BP, inundated the system and continuing rising sea-levels control contemporary biogeomorphologicaI environments; similarly, they pose a potential threat to human occupation and uses. Concerns relating to the future effects of climate change and sea-level rise have led to several studies specific to the Solent region (Ball et al., 1991; Bray et al., 1992, 1994, 1997). [This is a short paper; see the other Bray publications for more detail. Marsh sedimentation results of local relative sea-level (Cundy and Croudace, 1996) indicate 4 to 5 mm per annum at present. A model indicates increase in rate to 6.5 mm per annum by 2050 but there, of course, uncertainties.]
Bray, M.J., Hooke, J.M., Carter, D.J. and Clifton, J. 2000. Littoral transport pathways, cells, and budgets within the Solent. Pp. 103-106 in: Collins, M. and Ansell, K. 2000. Solent Science - A Review. Elsevier, Amsterdam, 385pp.
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Coad, J.G. 1985. Hurst Castle: The Evolution of a Tudor Fortress 1790-1945, Post Medieval Archaeology, vol. 19, pp. 63-104. [not seen by the present writer]
Coad, J.G. 1990. Hurst Castle, Hampshire. English Heritage. A 32 page, paperback, monochrome guide-book, first published in 1985, Second Edition 1991, 1995, 1997, 2000, 2001, 2003, 2004 and probably later, can usually be purchased at the Castle.
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Cole, A. 1926. [RE: A TSUNAMI AT HURST SPIT - IN 1882] Postmaster of Milford on Sea. Some Further Recollections of Milford, no. 23. Milford-on-Sea Record Society: Occasional Magazine, Volume 3, no 4, 1926.
"In September, 1882, a tidal wave [probably a tsunami from an earthquake] broke on the beach at Sturt filling up a considerable portion of Sturt Pond and the outlet, the salt water came up the Dane Stream, killing the fish, roach, carp, etc., and destroyed many of the apple trees in the gardens abutting on the stream. A new cutting was made near the original, but this soon filled up and the present one [in 1926] was made."
[important event - the last tsunami that is known to have hit Hurst Spit. There may have been many in the distant past.]
Craster, O.E., 1949. Hurst Castle, London, HMSO, [not seen by the present writer]
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Davison, M., Currie, I. and Ogley, B. 1993. The Hampshire and Isle of Wight Weather Book. Froglets Publications and Frosted Earth, Froglets Publications Ltd., Brasted Chart, Westerham, Kent, TN16 1LY. Paperback, 168pp. By Mark Davison, Ian Currie and Bob Ogley. With numerous monochrome photographs, many of them old and of historic interest.
"Everybody is fascinated by the ever-changing moods of the weather and the patterns of the sky. Our climate is a perpetual talking point, particularly in the days of great floods and freezes, tempests and tornadoes, droughts, hailstones and heatwaves. In recent years, Hampshire and the Isle of Wight have experienced all these variations. The sheer intensity of rain has turned quiet rivers into raging torrents, a clash of air masses has led to a spectacular snowstorm, global warming has been blamed for the longest drought in history, tidal waves, 20 feet high, have pounded the coast, a jet aeroplane has aquaplaned onto a motorway and opposing air streams have twice brought hurricane-force winds to change the face of the landscape. There has been more - much more - and in this unique pictorial record of the weather in Hampshire and the Isle of Wight, we have the evidence."
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Defoe, D. [Daniel Defoe book] 1705 [Probable date. Refers to 1703 storm which was obviously then recent and contains many letters dated 1704. Date not seen on the title page.] A Collection of the Most Remarkable Casualties Disasters which happen'd in the Late Dreadful Tempest both by Sea and Land on Friday the Twenty-fixth of November, Seventeen Hundred and Three. To which is added Several Suprising Deliverances. The Natural Causes and Original of Winds. Of the Opinion of the Ancients that this Island was More Subject to Storms than Other Parts of the World. With Several Other Curious Observations upon the Storm. The Whole Divided into Chapters under Proper Headings. 2nd Ed. George Sawbridge, London, 272 pp. [this is a very well-known book]
[In this storm the Eddystone light was destroyed and all its occupants drowned, and within the first six hours of the storm the Royal Navy had lost twelve ships and over 1700 men. In all some 8,000 people were killed, thousands more injured, and Britain looked and felt as if it had been transformed overnight into a war-torn country with a battlefield in every village and town. The author Daniel Defoe was in London at the time, and he used his own experiences of "this terrible Providence" as material for what became his first full-length book, The Storm, which he published the following year. Richard Hamblyn suggests that it was a hurricane boosted in its passage from North America to Britain.]
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Dyer, K.R. 1970a. Sediment distribution in Christchurch Bay, S. England. Journal of Marine Biological Association, U.K., 50, 673-682. By Dr. Keith Dyer.
Dyer, K.R. 1971. The distribution and movement of sediment in the Solent, southern England. Marine Geology, 11, 175-187. [Wrongly dated as 1970 in Dyer, 1972]. Abstract: Echo sounding, oblique Asdic surveying and sampling has shown the Solent to be extensively floored by gravel dunes. The dune asymmetry and the sediment distribution indicates transport eastwards from the principal source at Hurst Spit though with recirculating edies within the Solent. Current measurements show that the water flow meanders and that the recirculating eddies of sediments are associated with the positions of the meanders. The observed sediment distribution when compared with that predicted from the water flow shows that the gravel is often oversaturated with sand where currents are equal and opposite. Where the currents are asymmetrical the gravel is undersaturated with sand. Modified scree slopes appear where abrupt changes in the direction of sediment movement occur. [End of Abstract].
Dyer, K.R. 1972. Recent Sedimentation in the Solent Area. (Extrait du) Memoir Bureau Rech. Geol. Min., No. 79, 271-280. Abstract: Sparker surveys have shown that the river system, of which the Solent is a remnant, was incised to a base level of at least -50 m. Recent infilling of these channels in the east has been complex and is still continuing. In the west, evidence of the river channels has been mainly obliterated by erosion. Oblique asdic surveys have shown that the sea bed over much of the area is covered with dunes. Analysis of sea bed samples has shown that the dunes in the West Solent are composed of sandy-gravel with low shell content. Elsewhere sand and muds are important and shell content is generally higher. The predicted sediment transport paths show that coastal erosion in Christchurch Bay, on Selsey Bill and on the Isle of Wight is the main source of sediment. The relationship between the tidal currents and the sedimentary characteristics are discussed. [end of abstract]
Extract from the start:
Introduction: The Solent and Southampton Water form the drowned remnants of a previously extensive river system, the " Solent River", that drained the Hampshire Basin. The southern side of this basin was a land area which extended from Dorset through the Isle of Wight. During the Pliocene period the sea level stood at about + 200 m O. D. (Wooldridge and Linton, 1955), and most of the present land surface was under water. Subsequently the land rose relative to the sea, but with pauses that cut gravel covered levels. Some of these levels have horizontal segments thought to have been beaches formed of material eroded from older terraces (Everard, 1954a). Everard (1954 b) has also described submerged gravel and peat within Southampton Water. The maximum incision recorded within Southampton Water is to -24.4 m O. D. (Curry, Hodson and West, 1968). The breaching of the Isle of Wight - Purbeck ridge probably occured fairly late in the ensuing Flandrian transgression, but must have been followed by rapid erosion of the soft, plateau gravel covered, Tertiary rocks. Rapid erosion is still occuring in Christchurch Bay, on Selsey Bill and on certain sections of the Isle of Wight cost. The Solent now separates the Isle of Wight from the mainland of Hampshire. Within the Solent, the maximum water depths are 60 m in Hurst Narrows at the western end, and about 32 m in the Spithead. Elsewhere the channel depths are about 15 m, but shoals and banks occur, especially in the East Solent... [continues, with useful maps including those of carbonate content of sediment, mean grain size, distribution of dunes, and seismic profile surveys]
Dyer, K.R. 1980. Sedimentation and sediment transport. Pp. 20-24 in :
Burton, J.D. 1980. The Solent Estuarine System: an Assessment of Present Knowledge. N.E.R.C. Publications Series C, No. 22 November 1980, ed. J.D. Burton, 100 p. NERC. [Extract:]
Introduction: The Solent, Southampton Water and their tributary inlets form the drowned remnants of a previously extensive river system (see Section 2) which was incised to at least - 45m below present sea level. During the ensuing Flandrian transgression, the Isle of Wight Purbeck ridge was breached, and this has been followed by fairly rapid erosion during the last few thousand years, of the soft, plateau-gravel covered Tertiary rocks which has released large quantities of clays, sands and gravel. Continuing erosion indicates that an equilibrium configuration has yet to be attained.
The tidal conditions within the area are complicated (see Section 5) with a tidal range that can reach 5m at Southampton. Within the Solowing a smooth curve, the currents change direction before high or low water. There is generally only a short period of slack water during the tidal cycle and the currents are almost symmetrical. The small differences that do occur, however, appear to be significant in the sedimentation patterns. In contrast, slack water within Southampton Water and the other inlets coincides with high or low tide, and complicated effects due to a double peak on the flood tide and a double high water at spring tides are present. These factors produce a fast, short duration, ebb flow and a slower, longer flood flow, with a long period of slack water at high tide.
The coastlines of the area are exposed to wave action which is generally from a SW or SE quarter due to the
sheltering effect of the Isle of Wight. Maximum surface currents exceed 2m sec-l in the West Solent and l.5 m sec-l in the mouths of inlets such as Portsmouth Harbour.
Thickness of Sediment: Over most of the Solent area, seismic profiling has shown the sediment to be less than 2m thick. However, bare rock is not very extensive, and occurs only on the steep slopes of the channel in the West Solent, particularly in the vicinity of the Tertiary limestone ledges. The presence of other outcrops is shown by rolled clay fragments in some samples. Thicker sediments occur where the old river valleys have been filled in (Dyer, 1975), especially beneath the Brambles Bank, between the Nab Tower and St Helens Roads and beneath Calshot Spit, where a depth of 25m can be found.
Sedimentary Topography: Coastal features indicative of longshore sediment movement are common in the Solent area. Most of the estuaries and inlets have well developed spits (called 'duvers' on the Isle of Wight) which have been derived mostly from material from local cliff erosion (Fig 1), and some of the smaller inlets have been effectively sealed off. Tidal deltas occur at the entrances to Langstone and Chichester Harbours, while elsewhere it seems that the currents across the mouths of the inlets are too strong for deltas to be formed. However, bars are present across smaller inlets with low tidal prism volumes.
There are three main banks within the Solent. The Solent Bank in the West Solent previously had a barchan shape, but is now of much lower relief (Hydraulics Research Station, 1977)...[continues].
Dyer, K.R. and King, H.L. 1975. The residual water flow through the Solent, South England. Geophysical Journal of the Royal Astronomical Society, 42, 97-106.
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Everard, C.E. 1954a. The Solent river; a geomorphological study. Transaction of the Institute of British Geographers, 20, 41-58.
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Fouquet, M-P., Green, C.H. and Tunstall, S.M. 1992. Hurst Spit: an assessment of the benefits of coast protection: final report. Report commissioned by New Forest District Council, Middlesex University, Flood Hazard Research Centre. ISBN: 1859240682
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Fox, W.D. 1862. When and how was the Isle of Wight separated from the mainland?
Geologist, 5, 452.
[Initial theory of the Solent River. By the Reverend Fox. Although short - a classic! Full article follows: ]
---------------------------
SIR
- On two different occasions inquiries have been made in the pages of the 'Geologist,' as to the period at which the Isle of Wight was torn from the mainland and entrusted to the rude guardianship of the ocean. The subject is an interesting one, especially in its geological aspects; and as I have given some attention to it, I will attempt to reply to the inquiries of your Lymington correspondent.
I am not aware that there is the least particle of historical evidence that gives countenance to the famous passage in Diodorus Siculus that has been interpreted by various writers as proving that, when he lived, the channel of the Solent was fordable at low water. As the particular island of which Diodorus is speaking, was one from which the miners of Cornwall were in the habit of exporting their minerals, and there is a small isle (St. Michael's) on their own coast, to which such minerals could easily have been conveyed, and which, in its connection with the mainland, answers pretty closely to the historian's remarks; and further, as I know of no argument worth listening to why the miners of Cornwall should have transported their tin to the Isle of Wight for exportation, - on all these several grounds, I think one may safely conclude that neither Diodorus, nor any other writer of note, has left any evidencv whatsoever about the fordableness of the Solent, within historical times.
The severance of this island from the mainland, it appears to me, was effected under very unusual circumstances, and at a very distant period. The present channel of the Solent, being pretty nearly equally deep and equally broad throughout its entire length of twelve or fourteen miles, proves at once that it was not formed in the usual way of island-severing channels, that is, by gradual encroachments of the sea on the two opposite sides of a narrow neck of land. If so formed, the middle part of tbe channel would naturally have been both narrower and shallower than the two mouths that first admitted the tide towards it; but this is not the case. Nor are there any important indestructible obstructing rocks on either side of the channel that could account for this peculiar formation. It is to be accounted for, therefore, not by the excavations of a gradually approaching sea, but, as I shall hereafter have to attempt to show, by its being originally the trunk or outlet of a very considerable river.
Again, at the western mouth of the Solent, there is almost an immeasurable accumulation of rolled flints, with which are mingled a sufficient sprinkling of fragmental fossil shells of various genera and species to show us from whence, the whole mass was originally transported This accumulation forms a sort of natural breakwater, two miles in length, one hundred yards in breadth, and many feet in thickness, extending between the mainland at Milford and a point beyond midchannel, where Hurst Castle was erected three centuries ago. Where the castle stands, this bank of flints becomes expanded so as to cover a circular space of fully twenty acres. Now all this enormous accumulation of flints, together with another one probably much larger on the island side of the main channel, and lying under the sea, in front of Alum Bay and the Needles, are formed of drift and broken fossils from the Barton beds ; the fossils themselves plainly pointing to the formation whence the whole mass was derived. It would add too much to the length of my paper, to account for this vast lodgment of drift around the mouth of the Solent; neither is this needful as respects the objects of my remarks: only I would have my readers to understand that it depends upon the flow of tide through the channel of the Solent. And when it is remembered that the annual supply of drift along the Barton cliffs is comparatively small, it will then be seen that it must have required a period reaching far back in time to gather together the vast accumulations referred to above, and consequently they may be regarded in themselves as visible and lasting memorials of the very great antiquity of the separation of the Isle of Wight from the mainland.
Nay, I will venture to hazard an opinion, even though I stand without geological authorities to support me, that will place the date of the formation of the Solent Sea still further back in the dimness of the past; an opinion to which both the peculiarities of the channel itself above referred to, and the geological formation of the surrounding country,-bear very strong testimony. Whoever as a geologist examines the vertical strata of the chalk at the Needles, nay, and throughout the whole length of the Isle of Wight, and the strata of the same rock in exactly the same unusual, position on the bold white cliff on the Dorsetshire coast some twenty miles westward of the Needles, will not doubt but that the two promontories were once united, forming a rocky. neck of land from Dorset to the Needles. This chain of chalk might, or might not, be so cleft in twain as to, allow the rivers of Dorset and Wilts. to find a passage through them to the main ocean. My opinion, however, is that they had no such outlet, but that, at that far distant period, the entire drainage of more than two counties; embracing the rivers that join the sea at Poole and Christchurch, flowed through what is now called Christchurch Bay, down the Solent, and joined the sea at Spithead.
According to this theory, the Solent was at that time an estuary somewhat like the Southampton Water, having but one opening to the British Channel; but of so much more importance than the latter as it was fed by a vastIy greater flow of fresh water; and it further supposes that the bed of the Solent was scooped out originally by a river, which from the extent of its drainage one may guess to have been little inferior to, the Thames or the Humber. And this opinion acquires countenance from the circumstance that it accounts, in a most satisfactory way, for the equality of depth and breadth in the Solent Sea. Of course, according to this view, this sea would lose its original condition as an estuary at the time when the British Channel had so far made a breach through the chain of rocks connecting the Isle of Wight with Dorsetshire as to give an opening into itself for the Dorsetshire rivers, somewhere opposite to the town of Christchurch. From that time forth the Solent would become what it is at present; losing its character as an estuary, and assuming that of a long narrow sea. And at the same period, of course, the Isle of Wight would part with its peninsular character, and be severed from the mainland, but at a point far apart from that at which the severance is usually supposed to have taken place. The distant period at which such changes took place it would be hopeless to guess at, amid the dimness of the data on which calculations could be founded. It could not be less, however, than many thousands of years, seeing that since that time, the British Channel has not only made a broad breach of twenty miles through a chain of slowly yielding rocks, but has also pushed its way gradually across the broad extent of the Poole and Christchurch Bays.
In conclusion, I would observe, that if your correspondent at Lymington simply put his question about the separation of the Isle of Wight as an archaeological inquiry, I fear he will consider my answer to it as somewhat dreamy. But I am confident, if he and others who may honour me with a careful perusal of my observations, are tolerably acquainted with the geology of the neighbourhood, and have had their minds disciplined for realizing the operations of nature on a large scale and through lengthened periods of time, they will perceive in this paper opinions indicative of more than novelty, having, as I believe, very important geological facts to uphold them.
Yours, etc.,
W. Fox.
Brixton, Isle of Wight, Nov 8, 1862.
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Hooke, J.M., Bray, M., Carter, D. 1996. Sediment transport analysis as a component of coastal management - a UK example. Environmental Geology, vol. 27. Issue, 4, pp. 347-357. (staff from Department of Geography, University of Portsmouth.)
Detrimental effects of engineering works on the coast and a wish to conserve parts of the coastline have increased realization among coastal managers of the need to examine shoreline problems and proposals for protection in a wider spatial context than the site itself and over a longer time scale than the past few years. This paper outlines the approach taken in one region of the United Kingdom, the central south coast of England, to provide that wider perspective. Authorities responsible for coastal protection and sea defenses formed a coastal group, which, among other activities, commissioned research aimed at providing a greater understanding on which to base shoreline management decisions. A major project undertaken was a sediment transport study in which all existing information relating to coastal sediment processes in the region was collated and analyzed. All inputs, flows, and outputs of sediment were documented. Links between processes were examined for each part of the region. Finally, nine littoral cells of sediment circulation were identified and were suggested as forming a framework for shoreline management. The methods of compilation and analysis are outlined here and are exemplified for one area in the region. The approach is recommended as a cost-effective basis for strategic management of the coast in developed regions. [See also the related paper: Bray, Carter and Hooke, 1995.)
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James
, J. 1986. Hurst Castle: an Illustrated History. 134 pp. with many figures, including maps and photographs. Preface by Lord Montague of Beaulieu. The Dovecote Press Ltd, Stanbridge, Wimborne, Dorset, BH21 4JD. ISBN 0 946159 39 4. Original price 15 pounds, 95p. By Jude James, former President of the Hampshire Field Club, and born at Barton-on-Sea. [This is an interesting book and the various maps reveal the extent of coast erosion and aggradation. It is particularly recommended to anyone studying changes in the morphology of the spit, and especially in relation to the fixed point of Hurst Castle.]
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Larsen, A.O. The Langesundsfjord site; the minerals from the Norwegian syenite pegmatites. The syenite pegmatites in the Larvik plutonic complex in the Oslo Region, Norway, are famous for their diversity of minerals. To date, 175 different mineral species have been found in these classic localities, and 23 species have their type locality in the district. More than 200 years have passed since the first mineral discoveries were made here, and still there are much to be found. This homepage is dedicated to the study of these minerals. [continues].
Legg, R. 1999. Bridport and Lyme Regis: The Story of Dorset's Western Coast. Dorset Publishing Company. 192 pp. ISBN 0-948699-66-3. [With 37 monochome illustrations at the front and 61 at the back, many of them of old photographs, paintings and sketches. Local events, mostly regarding the coast are recorded in chronological order from the year 774 to 1998. Although references to sources are not given (and can be searched for elsewhere), this book contains much interesting information and informative old photographs. It is a paperback and at low cost - 7 pounds, 95 pence reduced to 4 pounds, 99 pence in April 2004. It should be found in the shops of Bridport and Lyme Regis. It is not a geological publication but has points of geological interest. The relevance of this book to Hurst Castle Spit is only in connection with storm events.]
Title Page:
"Strategy: The long term stabilisation of Hurst Spit is an important part of New Forest District Council's coastal strategy. It is a major
step in the development of the New Forest Coastal Management Plan and is the culmination of an extensive programme of research and monitoring. The strategy has been designed to provide an effective form of coast
protection to the low lying land adjoining the Western Solent, whilst maintaining the sensitive environmental balance of the area. This newspaper describes the
background of the project, the construction of the engineering works and the future management strategy for Hurst Spit."
Extract from page 2.
"Location:
Hurst Spit is sometimes aptly referred to as ''The Guardian of the Western Solent". The Spit is a prominent coastal feature which lies at the eastern end of Christchurch Bay. It was once a natural shingle barrier, sheltering the western Solent from severe wave action in south westerly storms.
It still performs that same role now, but can no longer be termed a natural feature in the purest sense. Before the scheme, the Spit was considerably smaller than it had been in the past and survived only as the result of artificial beach renourishment and reforming of the crest of the beach after severe storms.
Rooted to the mainland at Milford-on-Sea, Hurst Spit extends for some 2.5 kilometres to Hurst Castle and Hurst Point - the closest point on the mainland to the Isle of Wight. Beyond Hurst Point the Spit recurves back and extends in a north westerly direction into
the western Solent as far as the mouth of the Keyhaven river.
The Problem:
The Spit was once fed with a large natural supply of shingle from the beaches to the west, and from the local beach material which was eroded from the low cliffs that were once exposed at Milford-on-Sea.
That natural supply of material has now been reduced, due largely to the construction of coastal protection works further to the west. This has resulted in a rapidly changing coastline and a considerable threat to the safety of the low lying land in the western Solent.
The problem at Hurst Spit is, like many other coastal sites. around the country, partially the result of man's own efforts to protect the shoreline from erosion, as well as the result of natural processes. Historically much coast protection work in the U.K. has been carried out in response to local erosion problems. In many instances the response has been to provide a solution at that site with little regard for the effects that the work might have further along the coast. Complex legislation, unnatural administrative boundaries and difficulties in funding of the work has often meant that inadequate consideration has been given to the influence of the works at other sites. Recent changes in government funding, and improved understanding of coastal processes and design methods have resulted in much improved management of the coastline and design of more appropriate coastal protection schemes. Many
structures that were built twenty or thirty years ago would not now be considered as sensible solutions to the same problem.
The evolution of Hurst Spit is undoubtedly linked with the development of towns and villages along the coast of Christchurch Bay, and with the coast protection works that have been built to protect these developments from the sea. The problems at Hurst Spit are to some considerable extent the results of earlier coast protection schemes. The seawall at Milford-on-Sea provides protection to property from the sea, preventing erosion of the weak gravel cliffs, which were once exposed on the shoreline.
It has however stopped the natural supply of shingle from the eroding cliffs, which previously supplied Hurst Spit. Similarly the construction of groyne systems which are needed to maintain a beach in
front of the seawalls have resulted in slowing the rate of longshore transport of beach material on to Hurst Spit. Previous attempts to stabilise the western end of Hurst Spit have resulted in the construction of a rock armoured revetment. This has been extended on a number of occasions and is now 550 metres long. Whilst the problem appears to have been solved locally, it has been transferred further to the
east as a result. Even the construction of a terminal groyne at the junction of the shingle beach and the rock revetment has not been successful in preventing further erosion. As a result the natural alignment of the beach has been interrupted and it cannot reach a natural equilibrium position without becoming detached from the mainland and Hurst Castle. This will remain the case as long as the beach is connected with both Hurst Castle and the mainland. The only way that Hurst Spit could survive as a natural feature now would be by demolition of the seawalls, rock revetment and groynes at Milford, exposing the old cliffs once again. This would of
course mean that much residential property would be lost and frequent flooding of Milford would occur, due' to blockage of the Danes Stream, which provides drainage to the area. Clearly this is not an option that could seriously be considered.
As the supply of beach material to Hurst Spit has been reduced, the volume of the Spit has declined. The longshore transport of beach material along Hurst Spit is faster than the supply of beach material from the west. An estimated 30,000 tonnes of sand and shingle are lost from the Spit each year as a result. As the volume of the Spit has declined, it has become more vulnerable to breaching during storms. Prior to 1954 there are no records of breaches, although overtopping of the crest undoubtedly occurred. Since then however, the frequency of storm damage to the Spit has increased. In 1962 severe flooding of Keyhaven, occurred following breaching. Similar damage occurred in 1965, when the army was called upon to help rebuild the Spit. This was the introduction of the rock armour from Milford-on-Sea which has subsequently been extended and rebuilt on a number of occasions. A number of breaches occurred between 1973 and 1983, and the Spit was breached at least 9 times in 1983-84. The most severe damage along the full length of the Spit occurred in 1989, when the Spit was flattened along 800 metres of its length. The crest of the beach was lowered by as much as 2 metres during the storms. The shingle Spit rolled back towards Keyhaven across the salt marsh area by as much as 80 metres during one storm. Large areas of salt marsh which normally lay on the sheltered north eastern side of the Spit became exposed on the seaward side of the Spit following the storms. About 30,000 cubic metres of shingle was displaced into the Mount Lake river channel (the channel to the lee of the Spit), rendering the boat moorings inoperable and destroying large areas of salt marsh. Fortunately prompt action by New Forest District Council prevented more severe and permanent damage from occurring.
Maintenance:
Coast protection work at Hurst Spit is carried out by New Forest District Council. Prior to 1974, virtually no maintenance was carried out on the shingle bank, although coast protection work had taken place at Milford-on-Sea at the western end of the Spit during the 1960s. Maintenance of the Spit is usually carried out by reforming the beach crest with mechanical plant following storms, and by importing gravel rejects from gravel pits, or from an offshore dredging area. Hurst Castle has needed sea defence structures to protect it virtually since it was built in the 16th century and the works around the castle have been replaced regularly.
Maintenance costs have risen quite dramatically on Hurst Spit since the 1970s. By 1982 maintenance costs had risen from a few thousand pounds per year to 10,000 pounds and to 40,000 pounds in 1983. Such large sums of expenditure on maintenance were a considerable annual burden on New Forest District Council and concerns were expressed about the cost effectiveness of the maintenance work. Following. a report by consultants, all the organisations with interests in the Spit met to discuss whether the Spit should continue to be maintained. The answer was a resounding "yes". It was agreed also that a research programme and long term planned stabilisation programme should be developed over the next few years to replace unplanned emergency work. This research programme commenced in 1987, but in 1989 the costs of repairs following the severe winter storms was in excess of 440,000 pounds. This resulted in acceleration of the research work to provide a long term stabilisation programme."
[end of page 2, continues with Geology, etc].
New Forest District Council. 2004. New Forest District Coastal Management Plan, February 2004. [downloadable pdf file].
C5 Zone 5: Hurst Spit - Keyhaven and Lymington
Marshes.
"Features and interest
Description:
C5.1 This zone extends from Hurst Spit to the Lymington River. It includes the Spit itself, Keyhaven and its estuary and the extensive area of marshes to the east as
far as the Lymington River. As a landscape, this area is of considerable value, offering panoramic views of the coastal hinterland, and of the Solent and the Isle
of Wight. Keyhaven and the marshes are within the New Forest National Park.
C5.2 Close to the shoreline at Manor Farm, Pennington there is an extensive area of gravel workings. The excavations are gradually being filled with domestic and
inert waste, and restored for agricultural use.
C5.3 The zone is generally low lying and protected from flooding by Hurst Spit and the Lymington-Keyhaven sea wall. Following extensive damage and flooding during the winter storms of 1989/1990 the sea wall was rebuilt and raised in height. This varied coastal zone is dominated by Hurst Spit and the well-known coastal landmarks of Hurst Castle and lighthouse that guard the western
approaches to the Solent. The land is low-lying and particularly susceptible to flooding. The Spit and sea wall are the first line of defence against the sea,
but historically both have been breached or over-topped. The complex system of saltmarshes and mudflats lying in the lee of the Spit are renowned for their
outstanding scenic beauty, ecological significance and historical importance. The area has for many years been used for a variety of recreational activities,
and is a popular visitor destination on the New Forest coast..." [continues]
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Nicholls
, R.J. 1985. The stability of shingle beaches in the eastern half of Christchurch Bay. Unpublished Ph.D. Thesis, Department of Civil Engineering, University of Southampton. By Robert J. Nicholls, now Professor Robert Nicholls.
Nicholls, R.J. 1987. Evolution of the upper reaches of the Solent River and the formation of Poole and Christchurch Bay. pp. 99-114 in: Barber, K.E . 1987, Wessex and the Isle of Wight - Field Guide. Quaternary Research Association, Cambridge. Prepared to accompany the Annual Field Meeting held at Southampton and Cowes, 21-25 April, 1987. 180 pp. paperback. Edited and compiled by Professor Keith Barber, Department of Geography, Southampton University.
Nicholls, R.J. and Clarke, M.J. 1986. Flandrian peat deposits at Hurst Castle Spit, Proceedings of the Hants Field Club and Archaeological Society. 42: 15-21.
Nicholls, R.J. and Webber, N.B. 1987a. The past, present and future evolution of Hurst Castle Spit. Progress in Oceanography, 18, 119-137. Abstract: Previous models of the evolution of Hurst Castle Spit over-emphasised longshore growth at the expense of other processes, particularly rise in sea-level. Initially, a Pleistocene valley system was submerged creating a tidal strait, the West Solent, between Christchurch Bay and the East Solent. this almost certainly caused a major hydrodynamic change, transforming much of Christchurch Bay and the West Solent from a low to a high energy environment. Hurst Castle Spit and the Shingles Bank then began to form due to a combination of easterly littoral drift, offshore gravel movement due to the high tidal energy, a rising sea-level, the transformation of Hurst Beach due to overwashing and the formation of recurves due to waves in the West Solent. The growth of the Shingles Bank due to offshore sediment movement from Hurst Castle Spit was of particular importance because of the influence of wave energy along Hurst Beach. Significant local supplies of shingle in the vicinity of Hurst Castle Spit, reworked from Quaternary deposits were also of importance. Thus, it is not a classic multi-recurved spit and the transgressive segment, Hurst Beach, has much in common with barrier coastlines... The same processes are are continuing to shape Hurst Castle Spit at present, with additional effects of human interference in the coastal sediment system. The construction of sea defences at Milford-on-Sea in the period 1936 to 1968 has modified the sediment budget and Hurst Castle Spit is experiencing a phase of rapid evolution: maximum recession rates have increased from 1.5 metres per annum (1867-1968) to 3.5 metres per annum (1968-1982). It is difficult to quantify the exact role of sea-level rise in the present evolution of Hurst Castle Spit... The future evolution of Hurst Castle Spit will depend largely on man. If there is no further interference, which is highly unlikely, the beach will continue to decline, resulting in a further increase in the rate of recession. Ultimately, a true tidal breach will probably form, marking a new phase in the evolution of Hurst Castle Spit and its environs. However, shingle renourishment on another coastal engineering solution will probably be undertaken. The future rate of sea-level rise will have important long-term influences on all these options.
Nicholls, R.J. and Webber, N.B. 1987b. Coastal erosion in the eastern half of Christchurch Bay. In: Culshaw, M.G., Bell, F.G., Cripps, J.C. and O'Hara, M. (eds), 1987. Planning and Engineering Geology. Geological Society, London, Engineering Geology Special Publication, No. 4, pp. 549-554.
Abstract: Christchurch Bay has a long history of shoreline recession and this has given rise to some major coastal engineering problems. An area of particular concern is Hurst Beach at its eastern end, where the maximum rate of recession has increased from 1.5 m per annum (1867 to 1968) to 3.5 metres per annum (1968 to 1982). Hurst Castle itself is now subject to wave attack on part of its frontage. The littoral sediment movement was assumed to be essentially continuous around Christchurch Bay, but, in fact, a littoral drift sub-cell boundary (i.e. a partial barrier to littoral drift) is present in the vicinity of Hordle Cliff. Therefore, the increased recession of Hurst Beach is a local problem. Milford-on-Sea is situated on a thick sequence of Pleistocene Gravels, whose erosion contributed substantially to the maintenance of Hurst Castle Spit as a major physiographic feature. However, a series of coast protection works were constructed to protect Milford-on-Sea between 1936 and 1968, removing this important source of sediment.
In the long term, without any further human interference, recession rates of up to 6 metres per annum will probably occur along Hurst Beach. A breach of Hurst Beach is a major concern, as it would create an island at Hurst Castle and expose the vulnerable, low-lying, northern coast of the West Solent, including the village of Keyhaven, to increased wave attack and tidal scour. Ecologically important saltmarshes would also be destroyed.
Shingle renourishment is the only environmentally acceptable engineering solution. Limited renourishment has already commenced. Any cost benefit decisions must consider the wider implications of a breach in Hurst Beach, including environmental and ecological considerations.
This case study demonstrates the importance of a detailed understanding of both the littoral and offshore sediment movement for the planning of coast protection.
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Parker
, D.J. 1990. Coastal zone protection in east Dorset and Hampshire, United Kingdom. Research report to the OECD, Middlesex Polytechnic, Flood Hazard Research Centre. ISBN: 1859240429.
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Poole and Christchurch Bays, Shoreline Management Plan of the year 2010. Old records.
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Redman, J.B. 1852. On the alluvial formations and local changes, of the south coast of England. Proceedings of the Institute of Civil Engineers, 11, pp. 191-193. [Both Hurst and Calshot Spits seem to have undergone little change in their general outline for many centuries.]
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SCOPAC (Standing Conference on Problems Associated with the Coastline). Undated. Webpage: SCOPAC - Hurst Spit to Calshot Spit
The West Solent comprises the tidal channel between Brambles Bank to the east and Hurst Narrows in the west. It has an average width of 4.5km, and is narrowest (1,480m) at its western entrance. It is strongly asymmetrical in cross-section, with a much wider and shallower inter-tidal shoreface (up to 2,000m in width) along the mainland between Hurst Spit and the mouth of the Beaulieu River than on the Isle of Wight side. The main channel is on average 10-15m deep, but reaches 20m in depth at its eastern end and 60m at Hurst Narrows. Included within this unit is the low-lying northern Solent shoreline extending from the fixed, but partial transport boundary of Hurst Spit Photo 1) in the west to Calshot Spit Photo 2) in the east. Both boundaries are by-passed by the transport of fine fine sediment... [continues].
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Sibley and Cox, 2014. Flooding along English Channel coast due to long-period swell waves.
By Andrew Sibley and Dave Cox, Met Office, Hazard Centre, Flood Forecasting Centre, Exeter.
Introduction: Long-period swell waves have occasionally caused flooding in towns along the English
Channel coast, for instance Seaton and Portland in Lyme Bay, Hurst Beach in Christchurch Bay, and South Hayling Beach on Hayling Island. The beaches affected tend to be composed of shingle with a fairly steep slope, and these characteristics seem to be significant. The sudden onset of swell waves can also be hazardous for athers,
swimmers and walkers on other beaches around the southwest coast. These waves sometimes develop in association with trapped fetches: that is where the speed of the low pressure centre, with associated very strong winds on the southern flank, move roughly in line with the main wave group induced on the ocean surface. Bowyer and MacAfee (2005) have reported on work by the Canadian Hurricane Centre that seeks to model trapped fetch
waves in association with tropical and extratropical storms on the eastern seaboard of America. They note that the development of such events is highly sensitive to the speed, movement and strength of the storm system, and the gradient wind speed, in relation to the speed of the group wave speed. The largest swell waves develop on
the right flank of the direction of movement of the low pressure. If moving from west to east then the largest waves form on the southern flank. There is an optimum velocity of movement of the storm system in relation
to the group wave speed and the period of the fetch. So, over a 48h period, with a surface wind speed of 60kn, the storm system would need to match a speed of 26-27kn for optimal wave growth; over 72h it is about 28kn (Bowyer and MacAfee, 2005). In a fully developed sea-state the speed of individual waves over deep water approximates the wind speed. However, the group wavespeed is roughly half the single wavespeed, with individual waves moving through the wave group. So in trapped fetch events the speed of the low pressure centre
needs to be about half the mean wind speed at the sea surface. Over long distances it is necessary for the low centre to move relative to the curvature of the Earth. This has the effect of building the waves continually over a long period, perhaps in excess of 48h. Long-period swell waves may also develop and be maintained where there is a strong, fairly straight wind flow lasting for perhaps 24-48h. The developed individual wave
period is typically between 12 and 20s, and often greater than that of locally generated wind waves.
The UK sometimes receives long-period swell waves from extratropical storms developing in the western Atlantic, southeast of Newfoundland, but the energy dissipates somewhat over distance: that is unless it is
maintained by the forcing low-level winds keeping pace with the swell waves. This may happen with rapid cyclogenesis in the northwest Atlantic followed by progression of the low pressure centre so that the low-level
wind speed and movement of the low centre is harmonised with the wave group speed. Once in the English Channel, it would seem that such waves are refracted towards the English coast by the Hurd Deep that lies west to east in the middle of the Channel, but are also refracted further as they come into the shallow water near the coast
(Lapworth, 2011). In shallow water the wave speed c = vgd (where g is gravity, d is water depth), so waves moving into shallower water near the coast will be slowed, and the wave will appear to "bend" towards the
coast. The wave period T remains constant as the speed slows, so the wavelength L must shorten (L = cT). Because wave energy is conserved (ignoring the effect of friction) the wave will also grow proportionally in
height. The associated coastal flooding from such travelling waves often correlates with tidal surges and the close proximity of fairly deep low pressure centres, but not necessarily with locally generated high seas. [continues - please go to the full publication for more]
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Steers, J.A. 1946. The Coastline of England and Wales. pp.xix + 644. University Press, Cambridge.
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Strecheisen, A.L. 1974. Classification and Nomenclature of Plutonic Rocks. Recommendations of the IUGS Subcommission on the Systematics of Igneous Rocks. Geologische Rundschau. Internationale Zeitschrift fur Geologie. Stuttgart. Vol.63, p.773-785.
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Tyhurst, M.F. and Hinton, M.T. 199? The evolution of Poole and Christchurch Bays: Another Look at the Flandrian Transgression. By M.F.Tyhurst and M.T.Hinton.
Engineering Services Team, Christchurch Borough Council.
Civic Offices, Bridge Street, Christchurch, BH23 1AZ, 16 pp. Abstract: The development of (Poole and Christchurch Bays) cannot be assessed by reference to sea level rise alone; tidal range may have been the single nwst important factor. Similarly, coastal erosion processes must also be taken into account in understanding the mechanisms of development.
[The first part of the text now follows: Introduction: There have been many contributions over the years to the vexed question of how Poole and Christchurch Bays were born of the ancient Solent River complex. All agree that the Flandrian Transgression was the primary mechanism, with the latest evidence suggesting that the whole process started pre-Flandrian times. The authors, members of an operational coastal engineering team became interested during the preparation of the Poole and Christchurch Bays Shoreline Management Plan, the principal author serving on the Steering Group. They have now approached the subject from a coastal processes point of view and with a particular local focus on Christchurch, their "home" base.
Earlier Work: Probably the most popularly reproduced early image of the proto-Solent was by Reid, 1902 (1), who was studying the geology around Ringwood, Hants. He envisaged the Solent River starting life as the modem Frome, flowing through what is now Poole and Christchurch Bays on its way to north of the Isle ofWight. Everard, 1954 (2) looked more closely at the Hampshire Basin and showed the chalk ridge now more usually called the Isle of Wight monocline as a major directing influence on the route of the proto-Solent. West, 1980 (3) recognised the possibility of a breach in the chalk bastion, allowing the southerly capture of the Frome and ultimately to the disintegration of the proto-Solent. Nicholls, 1987 (4) studied many of the early contributions and developed a more detailed model for this southerly capture. More recently, Velegrakis, 1999 (5) demonstrated that the capture was-pre-Flandrian. Figures 2 - 5 illustrate the first four of the above-mentioned.
Crenulate Bays: Any experienced coastal engineer would be familiar with the crenulate (or spiral) shape of Poole and Christchurch Bays, as shown in Figure 6. Bays of this type form when soft cliffs attempt to reach a stable shape when constrained between hard headlands. Figure 6 would also indicate to the engineer that Christchurch Bay is much less developed than its sister and therefore younger. Poole Bay is well advanced and even has "offspring" mini-crenulates at its western end. The shape of the Bays, further, indicate the principal direction of attack, in this case from the southwest. Theory suggests that without intervention, Poole Bay would reach an equilibrium state when its development behind Ballard Down gave sufficient shelter for erosion to cease. A similar scenario can be applied to Christchurch Bay, the danger of which is discussed later. [continues]
No abstract is provided so the start of introduction is given here as an example of the text:
"It was more than 400 years ago when the first historians and geographers began to enquire into the nature and origins of the Solent as an open east-west seaway and the date at which it had precipitated the severance of the land of Wight The first recorded questions are those of William Camden, whose first edition of Britannia (published in 1586) included the mischievous speculation that the Isle of Wight, with its Roman name of Vectis, might perhaps be equated with a prehistoric island, otherwise known as Ictis.
A British island called Ictis had been cited in the 1st century BC, by the classical writer Diodorus Siculus; however, we should note that in describing Britain or "Prettanike," this classical historian commonly used the expressions "we are told" or "they say". The style of Diodorus indicates that he was relating the accounts of others and, unlike the earlier Greek explorer Pytheas, who had visited the Cornish coast in the 3rd century BC, it seems that he could offer no personal experience. His gatherings tell of an island close to the shore of southern Britain where the natives could cross at low tide whilst drawing wagons loaded with tin ore or ingots. These consignments were loaded into visiting ships bound for the Atlantic seaboard of Gaul (Rivet & Smith, 1979). Diodorus added that it was people dwelling near the promontory of Belerion (Land's End) who prepared this tin and transported it to the tied island of Ictis".. [continues]
Velegrakis, A.F. and Collins, M.B. 1992. Marine Aggregate Evaluation of Shingles Bank, Christchurch Bay. Southampton University Technical Report, SUDO/TEC/92/14C, 13pp.
Velegrakis, A. 2000. Geology, geomorphology and sediments of the Solent System. Pp. 21-43 in: Collins, M. and Ansell, K. 2000. Solent Science - A Review. Elsevier, Amsterdam, 385pp. By Dr. Adonis Velegrakis. [This contain useful maps showing the sea floor sediments southwest of Hurst Spit. (Figs 4 and 5)]
The Solent (Figure 1) forms the largest estuarine system of the southern coast of the UK. The constituent components of the system include the West and East Solent and their approaches, Southampton Water, Portsmouth, Langstone and Chichester Harbours and other smaller tributary river estuaries (e.g. Beaulieu, Lymington and Yar) found along the southern Hampshire and Isle of Wight coastlines. Parts of the coastline are characterised by coastal accumulation forms, such as barrier spits and islands (e.g. Hurst and Calshot Spits in the West Solent and Hayling Island in the East Solent), inter-tidal flats and salUnarshes (e.g. Lymington Flats). Erosional coastal environments (Le. coastal cliffs) are also present, particularly along the coastline of the Isle of Wight The offshore areas also show complex morphology (Figure 1), associated with several offshore banks and deeply-incised channels (e.g. Hurst Narrows).
The Solent has attracted a great deal of human economic development, including extensive urban and industrial development, agriculture, shipping, fisheries, recreation, marine aggregate extraction and offshore oil exploration (Shell, 1987). At the same time, the area is associated with important conservation areas such as the National Nature Reserves (NNR), Sites of Scientific Interest (SSSI), Local Nature Reserves (LNR), as well as important archaeological sites. This diverse human activity both influences and is influenced by the physical characteristics and dynamics of the natural environment Therefore, frequent monitoring is necessary, in order to assess the human impact on the environment and its evolution and, equaIly important, to understand and predict the influence of such evolution on the regional economic development The understanding of the dynamic interrelationships between nature and economic development forms the 'backbone' of 'sustainable development' policies, which emerge as the main UK and European Union environmental strategy.
The objective of this contribution is to review the present state of knowledge and identify gaps in information on some of the physical characteristics of the Solent Estuarine system and, particularly, its geology, geomorphology and sedimentology. In this sense, this contribution forms an update of the meticulous reviews of West (1980) and Dyer (1980)... [continues]
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Waters, R. 2018. New beach huts withstand a storm force battering. Lymington Advertiser and Times. Friday, 12th January 2018. By Roz Waters. Hundreds of tons of shingle thrown onto rebuilt prom [promenade]. [with a black and white picture, looking southeast, along the concrete huts]
A 2.3 million pound coastal improvement scheme incorporating 119 new beach huts at Milford [Milford-on-Sea, Hampshire] has withstood a major test after hundreds of tonnes of shingle were hurled onto a promenade during recent storms. The beach huts, which were opened in May 2017, were inspected by New Forest District Council's coastal engineering team last week, following storm force winds and waves in late December and early January. A combination of spring tides and several days of unsettled weather were blamed for dislodging a number of paving slabs from the sea front promenade close to the Needles Eye Cafe on Hurst Road. The coastal team estimated that between 400 and 500 tonnes of shingle was swept on the lower promenade in front of the new beach huts, and waves overtopping the coastal defences also deposited shingle in the sea front car parks. A specialist recording buoy close the coast at Milford showed wave heights were averaging 3m, in conditions which were expected to occur around four times a year. However, a spokesperson for the NFDC [New Forest District Council] explained that the height of the storm occurred over a period of spring tides, combining with a storm surge of around 0.6m, leading to larger than normal waves. She continued: "In addition the duration of this stormy period continued for three or four days, so a longer period of time for waves to overtop the defences", she said. "This also followed a very unsettled period of weather since around Christmasd Day. In any given years it is likely that we could experience the damage we have had, so nothing exceptional". Shingle from the beach has now been swept by NFDC's Streetscene team with a large HGV sweeper, and the collected material has been put back onto the beach." ....[continues for two paragraphs].
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West, I.M. 1980. Geology of the Solent Estuarine System.
In: The Solent Estuarine System: an Assessment of Present Knowledge, N.E.R.C. Publication Series C., No. 22 , November 1980. pp 6-18. Ed. J.D. Burton. [A concise review of knowledge of the geology of the estuaries up to 1980 with reference list, including discussion of the Eocene strata, the Pleistocene gravels and interglacial deposits, and the Flandrian Transgression of the submerged and partly buried valley system.]
West, R.G. and Sparks, B.W. 1960. Coastal interglacial deposits of the English Channel. Philosophical Transactions of the Royal Society of London, Series B., Biological Sciences, No. 701, Vol. 243, pp. 95-133, 27th October, 1960, with an Appendix on the Mammalia by A.T. Sutcliffe. Published by the Royal Society, Burlington House, Piccadilly, London W1. Communicated by H. Godwin, F.R.S. Addresses of authors: R.G. West - Subdepartment of Quaternary Research, University of Cambridge; B.W. Sparks, Department of Geography, University of Cambridge. Abstract: Fossiliferous Late-Pleistocene deposits on the foreshore of the English Channel at Selsey (Sussex), Stone (Hampshire), and near Arromanches (Calvados), have been investigated. At each site analyses of pollen, macroscopic plant remains and Mollusca have been made and from these vegetational, faunal, environmental and climatic conditions have been reconstructed. ... At Selsey, it is shown that the deposits, which lie in a channel cut in Eocene rocks, are of Ipswichian (Eemian or Last) Interglacial age. Pollen analysis of the sediments of the channel filling show that they formed during zones b, c, d, e and f of this interglacial, which show the succcession from open parkland vegetation to birch-, to pine, to oak-dominated forests. Analysis of the macroscopic plant remains and of the molluscs suggests a rapid climatic amelioration at the beginning of the interglacial, so that by the beginning of zone f there are indications of summer warmth exceeding that of the present day in the area. In the upper part of the channel filling, estuarine deposits overlie freshwater deposits. It is shown that the marine transgression causing the change was taking place in zone f and was probably responsible later for the raised beach deposits which overlie the channel deposits and form the cliff at Selsey Bill. ... At Stone pollen analysis shows that brackish water deposits, below present high tide level were formed in zone f of the Ipswichian Interglacial. At that time Quercus, Pinus, and Acer were the chief trees forming the forest in that region. The macroscopic plant remains and the Mollusca indicate that the deposit was formed under saltmarsh conditions. As at Selsey, the raised beach gravel found overlying the interglacial deposit is related to the same marine transgression that produced the brackish water conditions... Near Arromanches, at St Come de Fresne and Asnelles-Belle-Plage, two deposits showing a change from marine to freshwater sediments were investigated. The analysis of pollen and the Mollusca showed the prevalence of pine forest and its replacement by open steppe-like conditions as the marine regression occurred. After the regression, limon covered the freshwater deposits. The fossiliferous deposits are tentatively correlated with zone i of the Eemian Interglacial... The relative land and sea-level changes indicated by the deposits are considered. It is concluded that in the English Channel, during the Ipswichian (Eemian) Interglacial, sea-level rose above its present height in zone f and fell below it during zone i. The Selsey-Brighton raised beach and the Normannien II raised beach are correlated with the same marine transgression. It is pointed out that if the Selsey-Brighton raised beach is to be correlated with the Monastirian II level of 7-8m, then this level should be correlated with the Ipswichian (Eemian) Interglacial. [end of abstract.]
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White, H.J.O. 1915. The Geology of the Country near Lymington and Portsmouth. Memoirs of the Geological Survey of England and Wales, pp.v + 78. By H.J. Osborne White, F.G.S. Explanation of Sheets 330 and 331 (Mainland).
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Wright, D.
1998. Hurst Spit: the local authority perspective. Pp. 256-266 in: Bray, M. and Hooke, J. 1998b. Geomorphology and management sites in Poole and Christchurch Bay. (with contributions by other authors) Pp.233-266 in: Hooke, J. 1998. Coastal Defence and Earth Science Conservation. The Geological Society of London, Burlington House, London. 270 pp. ISBN 1-897799-96-9. [This provides a very good account of erosion,sea-defence works and related investigations and is recommended. Quantities of material used and costs are given.]
Wright, P. 1982. Aspects of the coastal dynamics of Poole and Christchurch Bays. Unpublished Ph.D Thesis. Department of Civil Engineering, University of Southampton, 201pp.
ACKNOWLEDGEMENTS
The generous help of Robert Nicholls is very much appreciated. He collected reworked fossil shells with me, many years ago, and helpfully discussed the origin and features of the beach which he was investigating for his Ph.D. thesis. More recently, I am particularly grateful to the New Forest historian - Jeremy Greenwood, for kindly providing me with information on the history of flooding in the area, and drawing attention to errors or weaknesses regarding historic matters. This has been very helpful. Various field parties have entered into discussion of Hurst Spit on field trips, and their comments are much appreciated.
Copyright
© 2020 Ian West, Tonya Loades and Joanna Bentley. All rights reserved. This is a private, academic website intended to be useful for research, reference and educational purposes, including lecturing. Images and text may not be copied for publication or for use on other webpages without permission or for any commercial activity. A reasonable number of images and some text may be used where appropriate for non-commercial, non-charged, non-online and non-published academic purposes, including field trip handouts, student projects, dissertations, lecture etc, providing the source is acknowledged. All images so used must contain the original caption, including the copyright statement. Some images are not those of the author and in that case the copyright is that of the original photographer and these are not for any use without specific permission from the source photographer. This particularly applies to aerial photographs, but also to some sets of field photographs.
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Geological fieldwork involves some level of risk, which can be reduced by knowledge, experience and appropriate safety precautions. Persons undertaking field work should assess the risk, as far as possible, in accordance with weather, conditions on the day and the type of persons involved. In providing descriptive field guides on the Internet no person is advised here to undertake geological field work in any way that might involve them in unreasonable risk from cliffs, ledges, rocks, sea or other causes. Not all places need be visited and the descriptions and photographs here can be used as an alternative to visiting. Individuals and leaders should take appropriate safety precautions, and in bad conditions be prepared to cancell part or all of the field trip if necessary. Permission should be sought for entry into private land and no damage should take place. Attention should be paid to weather warnings, local warnings and danger signs. No liability for death, injury, damage to, or loss of property in connection with a field trip is accepted by providing these websites of geological information. Discussion of geological and geomorphological features, coast erosion, coastal retreat, storm surges etc are given here for academic and educational purposes only. They are not intended for assessment of risk to property or to life. No liability is accepted if this website is used beyond its academic purposes in attempting to determine measures of risk to life or property.
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Webpage - written and produced by:
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Ian West, M.Sc. Ph.D. F.G.S.