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Surnaig Farm, Islay

Geological Conservation Review site | GCR #2678 | Structural and Metamorphic Geology | Dalradian

Scotland's geosites are chosen because of their local, national or international importance. Take only photos, leave only footprints: avoid causing any damage to this site. You can walk almost anywhere in Scotland without the need to ask permission or keep to paths, but you have a responsibility to care for your own safety, to respect people's privacy and peace of mind and to cause no damage.

The right of access does not extend to quarries, building sites or any land where public access is prohibited, or to the collection of geological samples.

Summary

Dalradian metabasite sills and feeder dykes. Syn-sedimentary sedimentary dykes

This site contain sedimentary dykes, a very unusual feature. In this site the dykes form two sets, approximately trending NW-SE and NE-SW, within phyllites and calcareous sandstones of the Port Ellen Phyllites. There are both folded and planar sandstone dykes which are remarkably well-preserved and exposed. These rare sedimentary structures are intrinsically important as prime examples of their type and also for the information they provide about palaeoenvironmental conditions during the deposition of the Easdale Subgroup of the Argyll Dalradian.
In additional two feeder dykes to the metabasite sills are exposed. The igneous intrusions are essentially synchronous with the sedimentation.

More information on GeoGuide

Site information

David Webster

March 14, 2020

NR 4079 4560

Metabasite sill to NE of Lagavulin

David Webster

March 14, 2020

NR 3977 4523

Metabasite feeder dyke to sills, sw of Lagavulin.

David Webster

Oct. 18, 2018

NR 3979 4524

Folded sandstone dyke, SW of Lagavulin.

David Webster

(PDF) Excursion 14 from the online version of the Guide to the Geology of Islay.