The BGS Lexicon of Named Rock Units — Result Details

Abbotsgrange Silt Member

Computer Code: AGSI Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Marine, well-bedded, very micaceous, black, grey and browish grey, loose silts, with many laminae and thin beds of fine-grained sand and dark grey silty clay. The unit has clasts up to 8cm of coal, basalt, mudstone and quartzite near its sandy base suggestive of local erosion of underlying strata. The deposit is considered to be prodeltaic in origin.
Definition of Lower Boundary: The relationship of the Abbotsgrange Silt Member (Forth Clay Formation) to the underlying Errol Clay Formation is probably unconformable. Never known to be in contact with the slightly older Kinneil Kerse Silt Member.
Definition of Upper Boundary: Overlain unconformably by younger deposits such as the Letham Silt or Claret Clay members (Carse Clay Formation) or by the Bothkennar Gravel Member (Forth Clay Formation).
Thickness: Veneer to 37m
Geographical Limits: On the southern side of the Forth estuary, from east of Kincardine Bridge to Bo'ness.
Parent Unit: Forth Clay Formation (FOCL)
Previous Name(s): Abbotsgrange Beds (-2560)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Grangemouth No.8 Borehole, BGS Ref NS98SE/119 from 30.95m to 68.00m in depth, Forth estuary. Browne, M A E, Graham, D K and Gregory, D M. 1984. Quaternary deposits in the Grangemouth area, Scotland. Report of the Institute of Geological Sciences, No.16/3. 
Reference(s):
Browne, M A E, Graham, D K and Gregory, D M 1984. Quaternary estuarine deposits in the Grangemouth area, Scotland. Report of the Institute of Geological Sciences, No.16/3. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S031