Wall Hill Member

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Wall Hill Member (WLH), Carboniferous, Midland Valley of Scotland[edit]

Wall Hill Member is part of the Ballagan Formation

Name[edit]

Previously named the Wall Hill Sandstone Group by Deegan (1973)[1], and the Wall Hill Sandstone Formation by Lintern and Floyd (2000)[2]. The status is here changed to a member and the ‘Sandstone’ epithet dropped.

Lithology[edit]

The member comprises fining-upwards cycles of pale grey to white conglomerates and sandstones with thin purple siltstones, ‘marls’ and shales.

Stratotype[edit]

The type section is the coastal outcrop between White Port Bay (NX 7234 4336) and Port Mary (NX 7550 4540) where the sequence comprises (base upwards) of about 210 m of conglomeratic sandstones, siltstones, ‘marls’ and shales with isolated dolostone nodules; 120 m of sandstones (sometimes conglomeratic), siltstone and shale; and more than 40 m of coarse conglomerates, interbedded with conglomeratic sandstones and a few thin red ‘marls’ (Deegan, 1973[1]; see also Lintern and Floyd, 2000, p. 83–85[2]).

Lower and upper boundaries[edit]

The base is unconformable on turbidites of the Silurian Raeberry Castle Formation, Riccarton Group.

The top of the member is faulted against the coarse conglomeratic red bed facies of the Orroland Member (Figure 10, Column 1).

Thickness[edit]

About 370 m

Distribution and regional correlation[edit]

Coastal outcrop between White Port (NX 7234 4336) and Port Mary (NX 7550 4540), south-west Scotland (Solway Firth).

Age[edit]

Tournaisian.

References[edit]

  1. 1.0 1.1 Deegan, C E.1973.Tectonic control of sedimentation at the margin of a Carboniferous depositional basin in Kirkcud-brightshire.Scottish Journal of Geology, Vol. 9, 1–28.
  2. 2.0 2.1 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)