The BGS Lexicon of Named Rock Units — Result Details

Wester Keolka Shear Zone

Computer Code: WKSZ Preferred Map Code: symbol
Status Code: Full
Age range: Ordovician Period (O) — Silurian Period (S)
Lithological Description: Blastomylonite, derived from Wilgi Geos Group and Sand Voe Group rocks.
Definition of Lower Boundary: The shear zone is probably a thrust that has juxtaposed Sand Voe Group rocks , that may be equivalent of the Moine Supergroup, against the Wilgi Geos Group of the Lewisian Gneiss Complex.
Definition of Upper Boundary: Not applicable.
Thickness: The blastomylonite is of mappable thickness.
Geographical Limits: The unit extends about 5 km from Garmus Taing on the north coast of Northmaven to Pettadale Water, and is then offset by faulting about 2 km to the east, then continues another 2 km until it abuts the Ronas Hill and Eastern granites.
Parent Unit: Not Applicable (-)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Area  Garmus Taing to Pettadale Water, North Maven. Mykura, 1976. 
British Geological Survey. 2004. Northmaven, Scotland Sheet No. 129, 1:50,000 scale. 
Mykura W, 1976 British Regional Geology: Orkney and Shetland (HMSO, Edinburgh).] 
1:50K maps on which the lithostratigraphical unit is found, and map code used: