| 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
|
| Stratotypes: |
| 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 |
| Reference(s): |
| 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: |
|
S095
|
