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Pathhead Formation (PDB), Carboniferous, Midland Valley of Scotland

The Pathhead Formation is part of the Strathclyde Group in the Fife area.

Name

From Pathhead, east Fife. The unit was originally described by Forsyth and Chisholm (1977)[1] and given formation status by Browne (1986)[2].

Lithology

The Pathhead Formation consists predominantly of mudstone and siltstone with beds of limestone and dolostone. Pale coloured, fine- to medium-grained sandstone is subordinate to the argillaceous rocks. Thin beds of coal and ironstone also occur.

Genetic interpretation

The overall pattern of sedimentation within the formation is of upward-coarsening deltaic cycles, with thinner upward-fining fluvial units erosively capping them, and relatively common marine incursions.

Stratotype

The type section is on the coast at Pathhead (NO 5419 0226 to NO 5381 0212) between St Monans and Pittenweem.

Lower and upper boundaries

The conformable base of the formation lies in a transitional sequence, the boundary being drawn at the base of the West Braes Marine Band (WBMB) above the Sandy Craig Formation (Figure 6, Column 4C), stratigraphically a little higher (Browne, 1986, fig. 2)[2] than that originally described by Forsyth and Chisholm (1977)[1].

The top of the formation is at the base of the Hurlet Limestone, present at the base of the Lower Limestone Formation (Clackmannan Group).

Thickness

The maximum thickness of the formation is about 220 m (Browne, 1986, fig. 2)[2].

Distribution and regional correlation

Fife.

Age and biostratigraphical characterisation

Visean (Brigantian). Marine bands are more common than in the underlying formations and their faunas are usually diverse and abundant. Curvirimula dominates the nonmarine faunas.

References

  1. 1.0 1.1 Forsyth, I H, and Chisholm, J I. 1977. The geology of east Fife. Memoir of the Geological Survey of Great Britain, Sheets 41 part 49 (Scotland)
  2. 2.0 2.1 2.2 Browne, M A E. 1986. The classification of the Lower Carboniferous in Fife and Lothian. Scottish Journal of Geology, Vol. 22, 422-425