The BGS Lexicon of Named Rock Units — Result Details

Colla Firth 'Group' [Obsolete Code: Use COLA]

Computer Code: DACF Preferred Map Code: notEntered
Status Code: Index Level
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Composed of micaceous psammite with subordinate semi-pelite, calc-silicate rock and crystalline limestone. Migmatitic gneiss also occurs.
Definition of Lower Boundary: Drawn at base of psammite of Colla Firth Group where it rests conformably on the Weisdale Limestone.
Definition of Upper Boundary: Drawn at conformable upward passage from psammite of the Colla Firth Group to the Girlsta Limestone.
Thickness: About 3500 m thick.
Geographical Limits: Shetlands, Scotland.
Parent Unit: Not Entered (?)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Colla Firth, Shetlands, Scotland. 
Reference(s):
Mykura W, 1976 British Regional Geology: Orkney and Shetland (HMSO, Edinburgh).] 
Harris, A L and others, 1973. A correlation of the Pre-Cambrian rocks in the British Isles. Geological Society of London Special Report No 6. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable