The Yesnaby Sandstone Group is a Devonian

lithostratigraphic Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology. In general, strata are primarily igneou ...

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic ide ...

(a sequence of rock strata) in west Mainland Orkney,

Scotland Scotland (, ) is a Countries of the United Kingdom, country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a Anglo-Scottish border, border with England to the southeast ...

. The name is derived from the locality of Yesnaby where the strata are exposed in coastal cliffs.

Outcrops

These strata are only exposed on either side of the Garthna Geo Fault in the Yesnaby area of west

Mainland, Orkney The Mainland, also known as Hrossey and Pomona, is the main island of Orkney, Scotland. Both of Orkney's burghs, Kirkwall and Stromness, lie on the island, which is also the heart of Orkney's ferry and air connections. Seventy-five per cent of O ...

Lithology and stratigraphy

The Group comprises the Qui Ayre Sandstone and the Harra Ebb Sandstone. The basal beds are talus and

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but a ...

facies deposited in a fluvial or lake marginal environment probably during the

Emsian The Emsian is one of three faunal stages in the Early Devonian Epoch. It lasted from 407.6 ± 2.6 million years ago to 393.3 ± 1.2 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It is named after the ...

Stage of the Devonian Period.British Geological Survey 1:100,000 scale geological map (Scotland) ''Orkney Islands'' (special sheet)

References

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External links

Yesnaby Geology Map
Geological groups of the United Kingdom Geologic formations of Scotland Devonian System of Europe Givetian Stage Stacks of Scotland Sandstone formations Siltstone formations Conglomerate formations Fluvial deposits Lacustrine deposits