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Provenance of the Old Red Sandstone: Pb isotope evidence from Arran, western Scotland

Published online by Cambridge University Press:  03 November 2011

A. P. Dickin
Affiliation:
Isotope Geology Unit, Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow G75 OQU, Scotland.

Abstract

Old Red Sandstone sediments from Arran in western Scotland yield an array of Pb isotope compositions whose slope corresponds to an age of 1830 ± 400 Ma. These compositions are not consistent with a significant contribution of material from the Southern Highlands, Midland Valley, or Southern Uplands, but are similar to the Torridonian sandstones of NW Scotland. Bearing in mind the probable Laxfordian provenance of the Torridonian assemblage, this points to a source for the Old Red Sandstone in a crustal block of early Proterozoic age corresponding to the age of the Laxfordian episode. Since such a source is not presently in a position to yield the Old Red Sandstone, strike-slip movement along the Highland Boundary fault is a strong possibility.

Type
Midland Valley
Copyright
Copyright © Royal Society of Edinburgh 1984

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