Skelda Ness
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Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Mineralogy of Scotland | Favourable | — | 2009-10-14 |
Geology & landscape
Rock Type: Granite
Landscape processes: Volcanic / Igneous
Description
Skelda Ness Skelda Ness SSSI lies at the southern tip of Skelda Ness, the southernmost part of the Walls peninsular of western Shetland. The area has abundant, excellent outcrops of coarse-grained, pink granite of the Sandsting Complex. This granite complex contains numerous crush belts, varying in thickness from 30 cm to 45 m, with a central mylonitic zone up to 5m thick of cherty appearance. This ‘cherty’ rock is composed largely of sodic scapolite enclosing thin streaks and lenticles of quartz-mylonite and sheared-out granite. Scapolite blebs and veinlets are also present. A crush belt cutting Skelda Ness contains such a vein of mylonitized scapolite, 1.8m thick. The scapolite is the sodic variety known as dipyre. Although scapolite is being increasingly recognised as a common mineral (previously often misidentified) this is still the best locality, as its usual ‘habitat’ of highly metamorphosed calcareous rocks is uncommon in Britain.