The BGS Lexicon of Named Rock Units — Result Details

Asta Spilitic Formation [Obsolete Code: Use ASSP]

Computer Code: DBAS Preferred Map Code: notEntered
Status Code: Index Level
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Metasedimentary phyllite along with hornblendic phyllites and coarse-grained hornblendic rocks.
Definition of Lower Boundary: Drawn at base of metaspilite of the Asta Spilitic Formation where it rests conformably on the Laxfirth Limestone.
Definition of Upper Boundary: Drawn at conformable upward passage from meta-spilite of the Asta Spilitic Formation to semi-pelite of the Clift Hills Phyllitic (Formation).
Thickness: 250m approx.
Geographical Limits: Shetlands, Scotland.
Parent Unit: Clift Hills 'Division' (DCF)
Previous Name(s): Asta Spilitic Group (-655)
Asta Spilite Group (-193)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Isles of Gletness, Shetland, 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. 
Flinn, D, and others, 1972. A revision of the stratigraphic succession of the East Mainland of Shetland. Scottish Journal of Geology, Vol.8, p. 335-343. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable