Yesnaby Sandstone Group
Appearance
Yesnaby Sandstone Group | |
---|---|
Stratigraphic range: Givetian (Devonian) | |
Type | Group |
Unit of | Old Red Sandstone Supergroup |
Sub-units | Qui Ayre Sandstone, Harra Ebb Sandstone |
Underlies | Caithness Flagstone Group |
Overlies | unconformable on 'basement' |
Lithology | |
Primary | Sandstone |
Other | Siltstone, conglomerate |
Location | |
Region | Orkney |
Country | Scotland |
Extent | West coast of Mainland, Orkney |
Type section | |
Named for | Yesnaby |
The Yesnaby Sandstone Group is a Devonian lithostratigraphic group (a sequence of rock strata) in west Mainland Orkney, Scotland. The name is derived from the locality of Yesnaby where the strata are exposed in coastal cliffs.[1]
Outcrops
[edit]These strata are only exposed on either side of the Garthna Geo Fault in the Yesnaby area of west Mainland, Orkney.
Lithology and stratigraphy
[edit]The Group comprises the Qui Ayre Sandstone and the Harra Ebb Sandstone. The basal beds are talus and alluvial fan facies deposited in a fluvial or lake marginal environment probably during the Emsian Stage of the Devonian Period.[2]
References
[edit]- ^ British Geological Survey. "Yesnaby Sandstone Group". BGS Lexicon of Named Rock Units. Retrieved 20 March 2022.
- ^ British Geological Survey 1:100,000 scale geological map (Scotland) Orkney Islands (special sheet)