Silurian–devonian magmatism, mineralization, regional exhumation and brittle strike-slip deformation along the loch shin line, nw scotland
Holdsworth, R. E.
Darling, J. R.
Strachan, R. A.
Finlay, A. J.
Porter, S. J.
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Holdsworth, R. E. Dempsey, E.; Selby, D.; Darling, J. R.; Feely, M.; Costanzo, A.; Strachan, R. A.; Waters, P.; Finlay, A. J.; Porter, S. J. (2015). Silurian–devonian magmatism, mineralization, regional exhumation and brittle strike-slip deformation along the loch shin line, nw scotland. Journal of the Geological Society 172 (6), 748-762
The Loch Shin Line is a geological-geophysical lineament associated with a zone of mantle-derived appinites, granites and strike-slip faulting that runs NW-SE across the Moine Nappe, northern Scotland. U-Pb zircon and Re-Os molybdenite dating of the Loch Shin and Grudie plutons, which lie immediately SW of the NW-SE Loch Shin-Strath Fleet fault system, yield c. 427-430 Ma ages that overlap within error. They also coincide with previously obtained U-Pb zircon ages for the Rogart pluton, which lies along-strike to the SE. Field and microstructural observations confirm the similarity and contemporaneous nature of the plutons and associated sulphide mineralization. Fluid inclusion analyses place further constraints on the P-T-X conditions during regional late Caledonian exhumation of the Moine Nappe. Synchronous to slightly younger brittle dextral strike-slip faulting along the WNW-ESE Loch Shin-Strath Fleet Fault System was probably antithetic to sinistral movements along the nearby Great Glen Fault Zone. Our findings support the hypothesis that the Loch Shin Line acted as a deep crustal channelway controlling the ascent and emplacement of Silurian magmas into the overlying Moine Nappe. We propose that this deep structure corresponds to the southeastern continuation of the Precambrian-age Laxford Front shear zone in the buried Lewisian autochthon.