|
The Sherwood Sandstone Group is a Triassic lithostratigraphic group (a sequence of rock strata) which is widespread in Britain, especially in the English Midlands. The name is derived from Sherwood Forest in Nottinghamshire which is underlain by rocks of this age.〔http://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=SSG (BGS on-line lexicon of rock units)〕 It has economic importance as the reservoir of the Morecambe Bay gas field, the second largest gas field in the UK. ==Geographical extent== These rocks are found in northwest England as far north as Carlisle (and extending just into Scotland around Annan and Gretna) and in the Vale of Eden and then extending down the Cumbrian coast into Lancashire and Cheshire. They are mostly obscured by superficial deposits but the highest coastal cliffs in northwest England at St Bees Head are formed in the St Bees Sandstone, the lowermost formation within the group.〔British Geological Survey 1;50,000 scale geological map sheet (England and Wales series) no 28 ''Whitehaven''〕 In the northeast they extend from Hartlepool south through the Vale of Mowbray and the Vale of York, then south through Nottinghamshire into the English Midlands, though are very largely concealed by superficial sediments. They occur widely through the Midlands (though usually concealed) and notably in an outlier at Leek, Staffordshire. They extend south to the Severn Estuary and beyond there through Somerset to Budleigh Salterton on the coast of East Devon. There are further occurrences in Northern Ireland north and east of Limavady, east of Cookstown, between Dungannon and Armagh and along the Lagan Valley beneath Belfast and Newtownards and on the Antrim coast.〔British Geological Survey 1:625,000 scale ''Bedrock geology UK South & UK North'' sheets〕 The Group comprises different sequences in each of the various basins in which it is developed as described below. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sherwood Sandstone Group」の詳細全文を読む スポンサード リンク
|