Skip to main content

New structural and Re-Os geochronological evidence constraining the age of faulting and associated mineralization in the Devonian Orcadian Basin, Scotland

Dichiarante, A. M.; Holdsworth, R. E.; Dempsey, E. D.; Selby, D.; McCaffrey, K. J.W.; Michie, U. Mc L.; Morgan, G.; Bonniface, J.

Authors

A. M. Dichiarante

R. E. Holdsworth

Profile Image

Dr Eddie Dempsey E.Dempsey@hull.ac.uk
Lecturer in Structural Geology, Programme Director (Geology and GPG)

D. Selby

K. J.W. McCaffrey

U. Mc L. Michie

G. Morgan

J. Bonniface



Abstract

The Devonian Orcadian Basin in northern Scotland belongs to a regionally linked system of post-Caledonian continental basins extending northwards to western Norway and eastern Greenland. Extensional fault systems that cut the Orcadian Basin sequences are commonly assumed to be Devonian, with some limited inversion and reactivation proposed during the Carboniferous and later times. We present a detailed structural study of the regionally recognized fault systems exposed in the Dounreay area of Caithness, which host significant amounts of authigenic mineralization (carbonate, base metal sulphides, bitumen). Structural and microstructural analyses combined with Re–Os geochronology have been used to date syndeformational fault infills (pyrite) suggesting that faulting, brecciation and fluid flow events are likely to have occurred during the Permian (267.5 ± 3.4 [3.5] Ma). Stress inversion of fault slickenline data associated with mineralization suggest NW–SE regional rifting, an episode also recognized farther west in Sutherland. Thus a dominant set of Permian age brittle faults is now recognized along the entire north coast of Scotland, forming part of the regional-scale North Coast Transfer Zone located on the southern margin of the offshore West Orkney Basin.

Journal Article Type Article
Publication Date 2016-05
Journal Journal of the Geological Society
Print ISSN 0016-7649
Electronic ISSN 2041-479X
Publisher Geological Society
Peer Reviewed Peer Reviewed
Volume 173
Issue 3
Pages 457-473
APA6 Citation Dichiarante, A. M., Holdsworth, R. E., Dempsey, E. D., Selby, D., McCaffrey, K. J., Michie, U. M. L., …Bonniface, J. (2016). New structural and Re-Os geochronological evidence constraining the age of faulting and associated mineralization in the Devonian Orcadian Basin, Scotland. Journal of the Geological Society, 173(3), 457-473. doi:10.1144/jgs2015-118
DOI https://doi.org/10.1144/jgs2015-118
Publisher URL http://jgs.lyellcollection.org/content/173/3/457
;