North West Highlands Geopark (2016) North West Highlands Geopark Geodiversity Audit and Action Plan 2013–2016
Additional notes: These web pages are sourced from the PDF North West Highlands Geopark Geodiversity Audit and Action Plan 2013–2016
NWHG Ref. 012 — Tarbet to Rubha Ruadh
Location, grid reference and photograph
The site lies on the west coast on the south side of the entrance to Loch Laxford, mostly north of Tarbet, Grid Ref. NC174506 —
GCR site reference, block, volume and notified feature of SSSI?
GCR Ref. 2438, Lewisian Block, Vol. 34. Confirmed GCR site, not SSSI notified feature.
Description and geological significance
The area provides a classic section across the Laxford Front within the Lewisian Gneiss Complex, illustrating the transition from largely unmodified Archaean (Scourian) basement gneisses to the south from Proterozoic reworked gneisses (Inverian and Laxfordian) to the north. It is internationally important as one of the first locations at which an episode of mafic dyke emplacement (ie. the Scourie Dyke Swarm) was used to separate tectonic events, creating a type of “pseudo-stratigraphy”.
Accessibility
Access requires a walk over very rough and frequently boggy and difficult terrain, either from Tarbet at the southern end, or westwards over steep and rocky slopes from the unclassified Tarbet–Fanagmore road. There is no access for all abilities.
Conservation
Low conservation requirement due to scale and location of the site area.
Visibility and “clarity”
The key features are not visible from the roadside and specialist assistance is required to identify them. Many of the features are still under scientific discussion.
Interpretation and interpretation potential
The site area is an important one for geology students and researchers and should be included in a future Geopark guide. It is important as an educational resource for university geology parties. An interpretative panel for the general public is not appropriate.
Key references
DAVIES, F.B. 1974. A layered basic complex in the Lewisian, south of Loch Laxford, Sutherland. Journal of the Geological Society of London, 130, 279–284.
PARK, R.G. 2009. Tarbet to Rubha Ruadh. In Mendum, J. R., Barber, A. J., Butler, R. W.
H., Flinn, D., Goodenough, K. M., Krabbendam, M., Park, R. G. & Stewart, A. D. (eds) Lewisian, Torridonian and Moine rocks of Scotland. Geological Conservation Review Series, 34, Joint Nature Conservation Committee, Peterborough, 141–144.
GOODENOUGH, K.M., PARK, R.G., KRABBENDAM, M., MYERS, J.S., WHEELER, J., LOUGHLIN, S.C., CROWLEY, Q.G., L, F.C.R., BEACH, A., KINNY, P.D. & GRAHAM, R.H. 2010. The Laxford Front: an end-Archaean terrane boundary? In Law, R., Butler, R. W. H., Holdsworth, R. E., Krabbendam, M. & Strachan, R. A. (eds) Continental Tectonics and Mountain Building: The Legacy of Peach and Horne. Geological Society, London, Special Publication, 335, 101–118.