Lithospheric-scale extension during Grampian orogenesis in Scotland

Viete, Daniel R., Richards, Simon W., Lister, Gordon S., Oliver, Grahame J.H., and Banks, Graham J. (2010) Lithospheric-scale extension during Grampian orogenesis in Scotland. Geological Society Special Publication, 335. pp. 121-160.

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Abstract

This contribution presents a new model for the Grampian-age tectonothermal development of the Buchan Block and Barrovian-type regions to its west, in the Grampian Terrane, Scotland. The model has drawn on evidence gathered from field mapping, microstructural analysis, metamorphic petrology and mafic magma geochemistry to propose that emplacement of the Grampian gabbros and regional metamorphic heating associated with production of Barrovian- and Buchan-type units occurred during syn-orogenic (Grampian-age), lithospheric-scale extension. Extension followed lithospheric thickening associated with the initiation of Grampian orogenesis and was followed by renewed lithospheric thickening and termination of the extensional heating. Mantle melting to produce the Grampian gabbros of the Grampian Terrane was achieved by extensional thinning of the lithosphere and decompression melting of the asthenosphere at depths of less than 70 km. Advection of heat from the mantle with emplacement of the Grampian gabbros augmented elevated heat budgets associated with attenuation of isotherms during extension. Deposition of the uppermost Dalradian (the Whitehills and Boyndie Bay Groups and the Macduff Slates) occurred during Grampian-age lithospheric extension. A gently-dipping, mid-crustal detachment focused metamorphic heat sources and accommodated significant lithospheric-scale strain, allowing independent thermal evolution of units in its hanging wall (the Buchan Block) and footwall (Barrovian-type units).

Item ID: 15762
Item Type: Article (Refereed Research - C1)
ISSN: 2041-4927
Date Deposited: 18 Mar 2011 01:01
FoR Codes: 04 EARTH SCIENCES > 0403 Geology > 040312 Structural Geology @ 50%
04 EARTH SCIENCES > 0403 Geology > 040313 Tectonics @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 100%
Citation Count from Scopus Scopus 9
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