Editing Quaternary deposits - Jersey: description of 1:25 000 Channel Islands Sheet 2

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| | Flandrian
 
| | Flandrian
 
|-
 
|-
| |
 
 
| | Peat and alluvium
 
| | Peat and alluvium
 
| | 10 m
 
| | 10 m
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| | ?Devensian
 
| | ?Devensian
 
|-
 
|-
| |
 
 
| | Head
 
| | Head
 
| | 30 m
 
| | 30 m
 
| | Devensian
 
| | Devensian
 
|-
 
|-
| |
 
 
| | St Peter's Sand (older blown sand)
 
| | St Peter's Sand (older blown sand)
 
| | 5 m
 
| | 5 m
 
| | ?Ipswichian
 
| | ?Ipswichian
 
|-
 
|-
| |
 
 
| | 8 m raised beach
 
| | 8 m raised beach
 
| | 3 m
 
| | 3 m
 
| | ?Ipswichian/Eemian
 
| | ?Ipswichian/Eemian
 
|-
 
|-
| |
 
 
| | Head
 
| | Head
 
| | 2 m +
 
| | 2 m +
 
| | ?pre-Ipswichian
 
| | ?pre-Ipswichian
 
|-
 
|-
| |
 
 
| | 18 in raised beach
 
| | 18 in raised beach
 
| | 2 m
 
| | 2 m
 
| | ?pre-Ipswichian
 
| | ?pre-Ipswichian
 
|-
 
|-
| |
 
 
| | 30 m raised beach
 
| | 30 m raised beach
 
| | 2 m
 
| | 2 m
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The 30 m beach is known from only two localities: South Hill, St Helier [6510 4770], and St Clement [6869 4738]. Together these show a height range between about 25 m and 37 m above mean sea level (Keen, 1978b). Only at South Hill can the sediments of this beach be examined, and there they consist of a medium gravel of the local Fort Regent granophyre and, quartz pebbles.
 
The 30 m beach is known from only two localities: South Hill, St Helier [6510 4770], and St Clement [6869 4738]. Together these show a height range between about 25 m and 37 m above mean sea level (Keen, 1978b). Only at South Hill can the sediments of this beach be examined, and there they consist of a medium gravel of the local Fort Regent granophyre and, quartz pebbles.
  
The 18 m beach is present in caves on the north-west coast of Jersey and on fragmentary benches below cliffs which rise to the main plateau of the island, as at Jubilee Hill (Mont du Jubile), St Ouen's Bay [5750 5145] (Renouf, 1969), St Helier (Renouf and Bishop, 1971), and at St Clement. In the caves it either occupies a bench cut into the solid rock or forms a false roof, as it does around Grand Becquet [5750 5628], where the beach is a cemented cobble gravel of local rock types. The best exposure is at the former terminus of the Jersey Eastern Railway at Snow Hill, St Helier [6543 4838] [[:File:P992209.jpg|(Plate 20)]], where medium gravel, composed almost entirely of local granite but with a few flint clasts (probably derived from offshore outcrops of Chalk), fills a pulley on the east side of the cutting. Both fine and coarse gravels are present at Jubilee Hill, and flints accompany the local rock types that make up the greater part of the deposit.
+
The 18 m beach is present in caves on the north-west coast of Jersey and on fragmentary benches below cliffs which rise to the main plateau of the island, as at Jubilee Hill (Mont du Jubile), St Ouen's Bay [5750 5145] (Renouf, 1969), St Helier (Renouf and Bishop, 1971), and at St Clement. In the caves it either occupies a bench cut into the solid rock or forms a false roof, as it does around Grand Becquet [5750 5628], where the beach is a cemented cobble gravel of local rock types. The best exposure is at the former terminus of the Jersey Eastern Railway at Snow Hill, St Helier [6543 4838][[:File:P992209.jpg|(Plate 20)]], where medium gravel, composed almost entirely of local granite but with a few flint clasts (probably derived from offshore outcrops of Chalk), fills a pulley on the east side of the cutting. Both fine and coarse gravels are present at Jubilee Hill, and flints accompany the local rock types that make up the greater part of the deposit.
  
 
Recent work on the raised beaches of the south coast of England and South Wales, using the amino-acid racemisation technique (Davies, 1983; Davies and Keen, 1985), suggests that at Portland, Torquay, Swallowcliffe (Avon), and in Gower, beaches reaching similar heights to the 18 m beach of Jersey have ages of around 200 000 ± 20 000 years.
 
Recent work on the raised beaches of the south coast of England and South Wales, using the amino-acid racemisation technique (Davies, 1983; Davies and Keen, 1985), suggests that at Portland, Torquay, Swallowcliffe (Avon), and in Gower, beaches reaching similar heights to the 18 m beach of Jersey have ages of around 200 000 ± 20 000 years.

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