Laggan Cottage Mudstone Formation

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Laggan Cottage Mudstone Formation (LNT), Carboniferous, Midland Valley of Scotland[edit]

Laggan Cottage Mudstone Formation is part of the Strathclyde Group.

Name[edit]

Taken from Laggan Cottage, north-east Arran (Paterson and Hall, 1986, p.14)[1].

Lithology[edit]

The Laggan Cottage Mudstone Formation consists of grey carbonaceous mudstone with subordinate sandstones. Plant remains occur but no coal seams are developed.

Genetic interpretation[edit]

The depositional environment was fluviodeltaic, mainly floodplain or lacustrine.

Stratotype[edit]

The type area is in the neighbourhood of Laggan Cottage, north-east Arran (NR 986 501) where the entire thickness of the formation is present.

Lower and upper boundaries[edit]

The base of the formation is taken at the faulted or unconformable top of the white sandstone forming the Millstone Point Sandstone Member of the Clyde Sandstone Formation at (NR 9887 5013) (Figure 6, Column 1).

The formation is overlain by lava and tuff of the Clyde Plateau Volcanic Formation at (NR 9855 5035).

Thickness[edit]

About 7 m (Paterson and Hall, 1986, p.14)[1]. However, BGS (1987)[2] gave a generalised thickness of 10–20 m.

Distribution and regional correlation[edit]

North-east Arran.

Age[edit]

Visean.

References[edit]

  1. 1.0 1.1 Paterson, I B, and Hall, I H S. 1986. Lithostratigraphy of the late Devonian and early Carboniferous rocks in the Midland Valley of Scotland. Report of the British Geological Survey, Vol. 8, No. 3
  2. British Geological Survey. 1987. Arran. Scotland Special Sheet, 1:50.000 Series. Bedrock. (Southampton: Ordnance Survey for the British Geological Survey.)