Brighton to Newhaven Cliffs

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Brighton to Newhaven Cliffs
Site of Special Scientific Interest
Peacehaven Cliffs - geograph.org.uk - 1204705.jpg
Location East Sussex
Grid reference TQ 390 014 [1]
InterestBiological
Geological
Area165.4 hectares (409 acres) [1]
Notification 1986 [1]
Location map Magic Map

Brighton to Newhaven Cliffs is a 165.4-hectare (409-acre) biological and geological Site of Special Scientific Interest and Geological Conservation Review site, [2] which stretches along the coast between Brighton and Newhaven in East Sussex. [1] [3] An area of 16.4 hectares (41 acres) is the Castle Hill, Newhaven Local Nature Reserve [4]

Contents

Geology

Brighton to Newhaven Cliffs provides the best and most extensive exposure of an important chronological fossil site in England. The gentle folding and the ease of access to the cliff exposures make this an important collecting site for faunas of the upper Santonian and lower Campanian. It is an increasingly important reference section for the Upper Cretaceous. Black Rock is a key for the study of Quaternary Stratigraphy and has attracted scientific interest for over 150 years. The modern sea cliff at Black Rock obliquely intersects a fossil cliff and abrasion platform cut in the Upper Chalk.

The platform is overlain by raised beach deposits of sand and shingle which contain shell fragments which amongst other methods have given the beach and cliff a general date from the second half of the last (Ipswichian) interglacial. The angle between the beach and the old cliff is filled by great quantities of coarse chalk rubble apparently derived from the weathering and erosion of the cliff in Devensian times. Chalk muds and fine chalk gravel and grit, are banked against the rubble on the west and may represent fan deposits. The muds contain appreciable quantities of loess and are overlain by further, coarser solifluction deposits. The chalk rubble and solifluction deposits are particularly notable for their fossil remains of many Devensian mammals, including Elephas primigenius, Tichorhinus antiquitatus and Equus caballus.

The landforms, stratigraphy and mammal remains at Black Rock provide an extremely valuable record of former sea levels and changing environmental conditions during the last few glaciations which have affected this area, Southern England, unlike much of the rest of the UK has not been affected by full scale glaciation. An area of the cliff at Saltdean provides probably the finest example of conjugate normal faults in the Chalk of southern England. This exposure of Upper Chalk lies on the southern flank of the Weald anticline, an upward flexure of the crust and the major geological structure of south-eastern England. The faults run in a north-northeasterly direction, at right angles to the trend of the anticline. These structures were probably formed by stretching of the crust parallel to the axis of the anticline during an episode of crustal compression in the mid Tertiary. The formation of the Wealden Anticline is related to the formation of the Alpine Chain to the South.

Along much of the cliffed coast between Brighton and Newhaven (and beyond to Eastbourne), frost involution structures can be seen in the upper meter of the chalk cliff. These involutions appear as repeated 'U' (festoon) shaped structures and date from the Devensisn (last glacial period). Frost heaving broke up the sub-surface sedimentary layers of chalk turning small slabs into a more and more upright orientation towards the surface, to be covered by present day soil. The centre of the 'U' structure is a fill of finer chalk and sands giving a more orange / yellow appearance. These structures have a polygonal surface manifestation which can be revealed by stripping away turf and soil. Slope angle appears to have had an effect on their formation. Where the gradient exceeds 20 degrees solifluction appears to have been a more dominant process preventing their formation. This may link to the patterned ground features of stone nets becoming elongated by gradient resulting in stone stripes as seen in modern periglacial environment and in relic locations such as Dartmoor.

Undercliff Walk

The Undercliff Walk is a 4.5 km (2.8 mi) path at the foot of the cliffs from Black Rock, Brighton to Saltdean. [5] Opened in 1933, [6] this seafront route is popular with walkers and cyclists. However, Brighton & Hove City Council has often had to close it after rockfalls such as during the winters of 2000/01, 2012/13, 2020/21 [7] and 2022/23. [8] Netting and other devices have been placed on parts of the cliffs known to be unstable to prevent rocks from falling on to the path. [9] [10] [11]

Related Research Articles

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<span class="mw-page-title-main">North Downs</span> Range of hills in south east England, UK

The North Downs are a ridge of chalk hills in south east England that stretch from Farnham in Surrey to the White Cliffs of Dover in Kent. Much of the North Downs comprises two Areas of Outstanding Natural Beauty (AONBs): the Surrey Hills and the Kent Downs. The North Downs Way National Trail runs along the North Downs from Farnham to Dover.

<span class="mw-page-title-main">Chalk Group</span> Stratigraphic Unit in England

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Roedean is a village in the city of Brighton and Hove, England, east of the seaside resort of Brighton.

<span class="mw-page-title-main">Saltdean</span> Village in Brighton, East Sussex, England

Saltdean is a coastal village in the city of Brighton and Hove, with part outside the city boundary in Lewes district. Saltdean is approximately 5 miles (8 km) east of central Brighton, 5 miles (8 km) west of Newhaven, and 6 miles (9.7 km) south of Lewes. It is bordered by farmland and the South Downs National Park.

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<span class="mw-page-title-main">Ashdown Formation</span>

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<span class="mw-page-title-main">Wadhurst Clay Formation</span>

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<span class="mw-page-title-main">Castle Hill, Newhaven</span> Park in East Sussex, England

Castle Hill, Newhaven is a 16.4-hectare (41-acre) Local Nature Reserve in Newhaven in East Sussex. It is owned and managed by Lewes District Council. It is part of Brighton to Newhaven Cliffs Site of Special Scientific Interest and Geological Conservation Review site.

The geology of the Gower Peninsula in South Wales is central to the area's character and to its appeal to visitors. The peninsula is formed almost entirely from a faulted and folded sequence of Carboniferous rocks though both the earlier Old Red Sandstone and later New Red Sandstone are also present. Gower lay on the southern margin of the last ice sheet and has been a focus of interest for researchers and students in that respect too. Cave development and the use of some for early human occupation is a further significant aspect of the peninsula's scientific and cultural interest.

The geology of the South Downs National Park in South East England comprises a gently folded succession of sedimentary rocks from the Cretaceous and early Palaeogene periods overlain in places by a range of superficial deposits from the last 2.6 million years. Whereas the South Downs are formed from the Late Cretaceous age chalk, the South Downs National Park extends into the Weald to the north of the range and thereby includes older rock strata dating from the Early Cretaceous including sandstones and mudstones. The youngest solid rocks are found on the southern fringes of the National Park in the eastern extension of the Hampshire Basin and include sand, silt and clay deposited during the Palaeocene and Eocene epochs.

References

  1. 1 2 3 4 "Designated Sites View: Brighton to Newhaven Cliffs". Sites of Special Scientific Interest. Natural England. Retrieved 11 January 2019.
  2. "Newhaven to Brighton (Cenomanian, Turonian, Senonian, Maastrichtian)". Geological Conservation Review. Joint Nature Conservation Committee. Retrieved 26 February 2019.
  3. "Map of Brighton to Newhaven Cliffs". Sites of Special Scientific Interest. Natural England. Retrieved 11 January 2019.
  4. "Designated Sites View: Castle Hill, Newhaven". Local Nature Reserves. Natural England. Retrieved 10 January 2019.
  5. "The Cliffs between Black Rock and Saltdean". Brighton & Hove City Council. Retrieved 13 June 2013.
  6. "CoastView - Roedean Cliffs". University of Sussex. Retrieved 21 February 2024.
  7. Lock, Rose (10 February 2021). "Undercliff walk closed after pedestrians hit by falling cliff debris". The Argus . Retrieved 19 January 2023.
  8. Carey, Jasmine (17 January 2023). "Saltdean Undercliff Walk closed after 'constant and significant' chalk fall". SussexLive. Retrieved 19 January 2023.
  9. "Undercliff Walk behind Brighton Marina to reopen". BBC News. 9 June 2013. Retrieved 13 June 2013.
  10. "Doing the Undercliff Walk". thisisbrighton.co.uk. Retrieved 13 June 2013.
  11. "Newsroom".

50°47′46″N0°01′44″W / 50.796°N 0.029°W / 50.796; -0.029