Gillfoot Sandstone Member

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Gillfoot Sandstone Member (GISD), Carboniferous, Northern England Province[edit]

Gillfoot Sandstone Member is part of the Border Group

Name[edit]

Originally named the Gillfoot Beds by Craig (1956)[1], and the Gillfoot Sandstone Formation by Lintern and Floyd (2000)[2].

Lithology[edit]

See Craig (1956)[1]; Deegan (1970)[3]. The member comprises interbedded medium- to coarse-grained sandstone and subsidiary conglomerate with limestone and siltstone.

Stratotype[edit]

The type section is Gillfoot Bay, Southerness, Kirkcudbrightshire (NX 9780 5430 to 9870 5610) where between 120 and 150 m of strata, comprised dominantly of sandstones and conglomerates with subordinate shales and fossiliferous marine beds, are exposed on the shore (Craig, 1956[1]; Lintern and Floyd, 2000[2]).

Lower and upper boundaries[edit]

The base has a gradational contact with strata of the Southerness Limestone Member (Figure 10, Column 2).

The upper boundary is taken as the top of the uppermost conglomerate associated with reddened strata, and is gradational with the interbedded mainly sandstone, sandy limestone and mudstone of the Powillimount Sandstone Member.

Thickness[edit]

Between 120 and 150 m.

Distribution and regional correlation[edit]

Gillfoot Bay, Southerness, Kirkudbrightshire, south-western Scotland (Southern Uplands).

Age and biostratigraphical characterisation[edit]

Arundian. Near the top of the member a shelly ‘rib’ yielded a fauna (possibly derived) including the coral Siphonodendron cf. scoticum and the brachiopod Punctospirifer scabricosta. S. scoticum occurs in Arundian to Asbian strata in Britain and the faunal evidence suggests that the Gillfoot Sandstone Member is Arundian in age (Lintern and Floyd, 2000 and references therein[2]).

References[edit]

  1. 1.0 1.1 1.2 Craig, G Y.1956.The Lower Carboniferous outlier of Kirkbean, Kirkcudbrightshire.Transactions of the Geological Society of Glasgow. Vol. 22, 113–122.
  2. 2.0 2.1 2.2 Lintern, B C, and Floyd, J D.2000.Geology of the Kirkcudbright–Dalbeattie district.Memoir of the British Geological Survey, Sheets 5W and 5E, part 6W (Scotland)
  3. Deegan, C E.1970.The petrology and sedimentology of the Lower Carboniferous rocks between White Port and Kirkbean, Kirkcudbrightshire. Unpublished PhD thesis, University of Wales, Aberystwyth