The BGS Lexicon of Named Rock Units — Result Details

Grantown Formation

Computer Code: GTWN Preferred Map Code: GF
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Weakly gneissose semipelite and subsidiary psammite beds, calc-silicate and metacarbonate rocks.
Definition of Lower Boundary: In part tectonic against underlying gneissose psammites and semipelites of Dava Succession - not seen.
Definition of Upper Boundary: Transitional, with increasing sandy content, up into psammites of the Nethybridge Formation, but contact relations not well exposed.
Thickness: max. 500m
Geographical Limits: Mid Spey Valley around Grantown-on-Spey, Central Highlands of Scotland, sheet 74E.
Parent Unit: Grampian Group (GRAM)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Area  Laggan Hill to Wester Laggan Farm, NE of Dulnain Bridge. 
Reference Section  Dulnain Bridge - roches moutonees adjacent to A95 on it's north side. 
Highton, A J, 1999. Solid geology of the Aviemore district, Memoir for 1:50000 geological sheet 74E [Scotland]. London: The Stationery Office. 97pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: