The BGS Lexicon of Named Rock Units — Result Details

Glen Tanar Quartzite Member

Computer Code: GTQ Preferred Map Code: SYMB
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Psammite, quartzitic to slightly feldspathic, with thin (<5cm) micaceous partings, and containing beds up to 1-2 metres thick of calc-silicate rock and impure limestone.
Definition of Lower Boundary: Change from dominant calc-silicate rock to dominant psammite at top of Deeside Limestone Formation (not seen south of Mount Battock Granite).
Definition of Upper Boundary: Gradational change, by thickening of micaceous partings, to become interbedded psammite and semipelite (where Glen Turret Psammite and Semipelite Member is present). Elsewhere incoming of beds of semipelite with high magnetic susceptibility (Glen Effock Schist Formation).
Thickness: (i) North of Mount Battock Granite: probably no more than 500m (top cut out by granite). (ii) South of Mount Battock Granite: probably c. 1250m exposed, with little tectonic thickening (base not seen).
Geographical Limits: (i) Deeside: north of Mount Battock Granite and south of Deeside Limestone Formation from NO 413 943 to NO 565 955; (ii) Invermark - Tarfside: south of Mount Battock Granite and north of the Glen Effock Schist Formation from NO 415 845 to NO 545 825.
Parent Unit: Tarfside Psammite Formation (TPS)
Previous Name(s): Glen Tanner Quartzite [Obsolete Name And Code: Use GTQ] (DBGT)
Alternative Name(s): none recorded or not applicable
Type Area  (South of the Mount Battock Granite). Good exposures of flat-lying psammite, calcareous psammite and minor calc-silicate rock in Branny Burn section (but only limited stratigraphic thickness exposed). 
Type Area  (North of Mount Battock Granite). Good exposures of massive, quartzitic psammite with 1-30cm layers of slightly calcareous psammite on the banks of the Water of Tanar from 100m above to 50m below the Brig O' Ess. 
Smith, C G, Goodman, S and Robertson S. 2003. Geology of the Ballater district. Memoir of the British Geological Survey, Sheet 65E (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S065 S066