The BGS Lexicon of Named Rock Units — Result Details

Crathie Point Calc-Silicate Member

Computer Code: CRPT Preferred Map Code: CrPt
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Thin-bedded flaggy calc-silicate, calcareous semipelite and impure metacarbonate rock, with beds of metalimestone; bands of distinctive schistose garnet-muscovite-biotite semipelite in upper part. Calcareous psammite beds sparse but more abundant near top.
Definition of Lower Boundary: Base of lowest limestone bed in sequence of flaggy semipelites and psammites of Cairnfield Calcareous Flag Formation.
Definition of Upper Boundary: Transitional decrease in frequency of limestone beds and increase in proportion of calc-psammites relative to calc-semipelites.
Thickness: c.200 to 250m on coast section, but locally tightly folded; not measurable inland.
Geographical Limits: From coast at Crathie Point [NJ 5475 6725 - 5495 6715], as far inland as Broom [NJ 543 662], south of which it cannot be distinguished from the rest of the Cairnfield Calcareous Flag Formation.
Parent Unit: Cairnfield Calcareous Flag Formation (CCFL)
Previous Name(s): Crathie Point Calcareous Flag Member (-2118)
Middle Portion Of Crathie Point Calcareous Group (-3333)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  On coast at Crathie Point. 
Reference(s):
Stephenson, D, et al. 1993. Stratigraphy and correlation of the Dalradian rocks of the East Grampian Project area. British Geological Survey Technical Report WA/93/91. 
Stephenson, D and Gould, D , 1995. British Regional Geology: the Grampian Highlands (4th edition). (London: HMSO for the British Geological Survey), 67-68. 
Read, H H, 1923. Geology of the country around Banff, Huntly and Turriff, Lower Banffshire and north-west Aberdeenshire. Memoir of the Geological Survey, Scotland Sheets 86 and 96 (Scotland). 
Harris, A L, Haselock, P J, Kennedy, M J and Mendum, J R, 1994. The Dalradian Supergroup in Scotland, Shetland and Ireland. 33-53 in Gibbons, W E and Harris, A L (editors). A revised correlation of Precambrian rocks in the British Isles. Special Report of the Geological Society, London, No.22. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S096