Yesnaby Sandstone Group
| Yesnaby Sandstone Group | |
|---|---|
| Stratigraphic range: Givetian (Devonian) | |
 Dune cross-bedded aeolian Yesnaby Sandstone exposed in the cliffs at Yesnaby and on Yesnaby Castle sea stack | |
| 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)