The BGS Lexicon of Named Rock Units — Result Details

Den Siltstone Member

Computer Code: DSF Preferred Map Code: notEntered
Status Code: Full
Age range: Emsian Age (DE) — Emsian Age (DE)
Lithological Description: Mainly green and greenish grey calcareous flaggy siltstones with subordinate silty sandstones and sporadic thin limestones. Some maroon and grey units. Beds of red breccio-conglomerate developed at the base.
Definition of Lower Boundary: Contact not exposed, but mapped as an angular unconformity on gneissose feldspathic psammite of the Rosemarkie Metamorphic Complex (Moine). Lowest beds in the sedimentary sequence are not exposed, but the oldest exposed beds are downfaulted against Rosemarkie Metamorphic Complex (Moine) rocks.
Definition of Upper Boundary: Generally mapped as being unconformably overlain by beds of bouldery conglomerate containing well-rounded clasts of igneous and metamorphic rock including granite, gneissose psammite and porphyritic andesite. The conglomerate is assigned to the Kilmuir Conglomerate Formation (Fletcher et al, 1996). Only one exposure of the contact is known [NH7263 5359] where an apparently concordant boundary occurs between fine-grained sandstone and the overlying conglomerate.
Thickness: To c.150m
Geographical Limits: Not defined.
Parent Unit: Braemore Mudstone Formation (BRMU)
Previous Name(s): Den Siltstone Formation (-4498)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Sheet 84W. (NH75NW). 
Partial Type Section  Exposures in Ross-shire County Highways Depot at Roremarkie Quarry, c.1.5km northwest of the centre of Rosemarkie village. Fletcher et al., 1996. 
Reference(s):
Fletcher, T P et al. 1996. Geology of the Fortrose and eastern Inverness district. Memoir of the British Geological Survey, Sheet 84W (Scotland). 
Horne, J, 1923. The geology of the Lower Findhorn and Lower Strath Nairn. Mmemoir of the Geological Survey of Scotland Sheet 84 and prt of 94. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S084