The BGS Lexicon of Named Rock Units — Result Details

Markie Gneisses

Computer Code: MARK Preferred Map Code: notEntered
Status Code: Index Level
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Gneissose micaceous psammite with lenses and sheets of locally agmatitic psammite. Subsidiary psammite and gneissose semipelite.
Definition of Lower Boundary: Not seen.
Definition of Upper Boundary: Overlain by semipelite correlated with the Coire nan Laogh Semipelite Formation which in turn is overlain by the Loch Laggan Psammite Formation. Boundary with the semipelite is inferred to be an unconformity.
Thickness: Unknown.
Geographical Limits: Central part of 63E extending 10km. north-east in a number of fault blocks close to the Markie Fault from Loch Crumachdan [NN 545 928] to Meallan Dubh [NH 000 815].
Parent Unit: Not Applicable (-)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Reference Section  Burn section in the Allt Coire nan Eumlainn Fiadhaich extending east for 350m from a point 350m east of the Markie Burn. 
Robertson, S and Merritt, J W [in prep.]. Geology of the Dalwhinnie district. Sheet description of 1:50000 sheet 63E [Scotland]. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: