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.
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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.
Site information
David Webster
March 14, 2020
Metabasite sill to NE of Lagavulin
David Webster
March 14, 2020
Metabasite feeder dyke to sills, sw of Lagavulin.
David Webster
Oct. 18, 2018
Folded sandstone dyke, SW of Lagavulin.
David Webster
(PDF) Excursion 14 from the online version of the Guide to the Geology of Islay.