Sel Ayre
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Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Quaternary of Scotland | Favourable | — | 2005-03-31 |
Geology & landscape
Geological Period: Quaternary · Rock Type: Glacial Till
Landscape processes: Glacial, Periglacial
Description
Sel Ayre Sel Ayre, on the west side of the Walls peninsular on Shetland Mainland, is an important site for Quaternary studies. The interest comprises organic deposits interbedded with sand and gravel and overlain by gravel and glacial till. Pollen analysis and dating evidence suggest that the organic deposits formed during an interstadial phase around 100,000 years ago (Marine Isotope Substage 5c). The deposits at Sel Ayre record major environmental changes during and following the interstadial, and it is one of only a very few sites in Scotland representing this time interval. The vegetation changed from grass-and fern-dominated communities on fertile, brown-earth soils to ericoid dwarf-shrub heaths on acid podzsols and peats, then to grass-dominated vegetation typical of skeletal mineral soils. The overlying sand and gravel is characteristic of a periglacial (cold-climate) environment and indicates marked climate deterioration followed by the onset of the Devensian glaciation (approximately 70,000 years ago). Sel Ayre therefore provides key information for interpreting the Late Quaternary history of northern Britain.