Rascarrel Member

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Rascarrel Member (RASC), Carboniferous, Northern England Province[edit]

Rascarrel Member is part of the Border Group

Name[edit]

Previously known as the Rascarrel Sandstones and Conglomerates by Craig and Nairn (1956)[1], and the Rascarrel Group by Deegan (1973)[2], the status has been changed from a formation to a member and the “Sandstone” epithet removed.

Lithology[edit]

Conglomeratic sandstone interbedded with thin beds of ‘marl’ and siltstone, and subsidiary coal and mudstone.

Stratotype[edit]

Partial type sections include coastal sections between Castle Muir Point (NX 7980 4710) and Rascarrel Burnfoot (NX 8030 4800) where there are more than 360 m of sandstone, ‘marl’, and siltstone with thin mudstones and coals; and between Castlehill Point (NX 8545 5240) and Gutcher’s Isle (NX 8635 5265) where the sequence includes a basal breccia, conglomerate, sandstone and shale, perhaps 21 m thick (see Craig and Nairn, 1956[1]; Deegan, 1973[2]; Lintern and Floyd, 2000[3]).

Lower and upper boundaries[edit]

The base has faulted and unconformable contacts with the calcareous greywackes and silty mudstones (hornfelsed where they occur within the aureole of the Criffel Granodiorite) of the Ross Formation (Hawick Group). In the Rerrick Outlier the member is faulted against the conglomerates, conglomeratic sandstones, sandstones, red siltstones, ‘marls’ and pedogenic dolostones (‘cornstones’) of the Orroland Member (Ballagan Formation).

The top of the member is not seen, and Lintern and Floyd (2000, p. 86)[3] indicate that no rocks of Namurian or Westphalian age are present on the Kirkudbright–Dalbeatie coast.

Thickness[edit]

More than 360 m.

Distribution and regional correlation[edit]

Rascarrel Bay (Rerrick Outlier); Castlehill Point to Gutcher’s Isle and Portling to Portowarren shores (Colvend Outlier), Kirkcudbrightshire, south-western Scotland (Southern Uplands).

Age[edit]

Arundian to Holkerian.

References[edit]

  1. 1.0 1.1 Craig, G Y, and Nairn, A E M.1956.The Lower Carboniferous outliers of the Colvend and Rerrick shores, Kirkcudbrightshire.Geological Magazine, Vol. 93, 249–256
  2. 2.0 2.1 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
  3. 3.0 3.1 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)