The BGS Lexicon of Named Rock Units — Result Details

Hempriggs Sand Member

Computer Code: HRGS Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Typically medium- to fine-grained sand pale yellow to pale orange in colour, in cross-stratified units. Sands display soft-sediment deformation and glaciotectonic deformation structures. Some discontinuous silt partings are commonly present in the fine-grained sand units. Thin discontinous beds (typically 5 to 10 cm thick) of sandy pale brown diamicton are present in the upper parts of the unit at some localities.
Definition of Lower Boundary: Not seen; mapping indicates erosional contact on Till (Finglack Till Formation), Glaciofluvial outwash of the Main Late Devensian Glaciation, laid down prior to the Elgin Oscillation and Old Red Sandstone bedrock.
Definition of Upper Boundary: The base of the Milton Hill Silt Member.
Thickness: Composite sections indicate a typical thickness of 5-10m.
Geographical Limits: The deposit underlies a discontinuous curvilinear ridge that extends northwestwards from 2.6km east of the centre of Forres, a distance of 8.5km to Easter Coltfield [NJ 1202 6440] and isolated undulating ridges rising to between 45m and 55m AOD east of Forres. All known exposures lie within the SW corner of the Elgin Sheet.
Parent Unit: Grange Hill Sand Formation (GRHS)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Reference Section  Sand Pit on Kinloss Golf Course, 1.06km NNW of Spot Height on top of Grange Hill. Cross-bedded pale yellow medium- to fine-grained micaceous sand with sparse partings of pale brown silt; some contorted laminations and soft sediment deformation ('flame structures'). Low-angle tabular foresets; cosets fine upwards suggesting waining turbidity flows. Some ripple drift lamination and a thin bed (c.10-12 cm thick) of sandy till in upper part of sand unit. Up to 4.2m of section exposed. 
Type Section  Former section in disused sand pit, 215m SE of Upper Hempriggs farm; from Elgin Memoir and original notes on field map. Brown Till, 0.3-0.7m thick, overlying sand and silt, 9.1m thick; with gravel lenses and faults lined with indurated sandy clay; 'balls' of rock flour occur within the sand. Cross- bedding within the sand dips towards the north east. Sand dominated sequence with faulting and ball and pillow structures 
Geology of the Elgin District Geological Survey Scotland Memoir Sheet 95 (Peacock et al; 1968). 
1:50K maps on which the lithostratigraphical unit is found, and map code used: