Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

Geological Magazine

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by OSINSKI, G. R. Articles by OLIVER, G. J. H. Search for Related Content GeoRef GeoRef Citation

Extensional tectonics of the Outer Hebrides Fault Zone, South Uist, northwest Scotland

G. R. OSINSKI^*, G. I. ALSOP and G. J. H. OLIVER

Crustal Geodynamics Group, School of Geography & Geosciences, University of St Andrews, Fife, Scotland KY16 9AL, UK

Author for correspondence: gia{at}st-and.ac.uk (Ian Alsop)

The Outer Hebrides Fault Zone is a major ESE-dipping reactivated structure within Lewisian basement gneisses of the Laurentian craton, northwest Scotland. Detailed mapping in South Uist reveals important new evidence that contributes to a better understanding of the kinematic evolution of the fault zone. Large quantities of pseudotachylite which characterize the fault zone on South Uist may in part be lithologically controlled, and therefore of little value in determining areas of greatest deformation and displacement. Only limited evidence is preserved for ductile and brittle thrust-sense movements along this portion of the fault zone. The tectonics of the fault zone on South Uist are dominated by structures associated with several episodes of pervasive top-down-to-the-SE to -ENE brittle extensional deformation, which are progressively overprinted by protophyllonitic and phyllonitic fabrics associated with top-down-to-the-E to -ENE extension. A series of late-stage high-angle normal faults record top-down-to-the-ESE to -ENE extension and cut the phyllonites. Fluid inclusion studies from syntectonic quartz veins constrain the conditions of phyllonite formation at 370 ± 20 °C. Field evidence suggests that this section of the Outer Hebrides Fault Zone may have been largely unaffected by sinistral strike-slip reactivation as reported along-strike to the north, suggesting both a varied and compartmentalized tectonic and evolutionary history along the length of the Outer Hebrides Fault Zone.

This article has been cited by other articles:

				S. C. Sherlock, R. A. Strachan, and K. A. Jones High spatial resolution 40Ar/39Ar dating of pseudotachylites: geochronological evidence for multiple phases of faulting within basement gneisses of the Outer Hebrides (UK) Journal of the Geological Society, December 1, 2009; 166(6): 1049 - 1059. [Abstract] [Full Text] [PDF]

				A. G. SZULC, G. I. ALSOP, and G. J. H. OLIVER Kinematic and thermal constraints on the reactivation of the Outer Hebrides Fault Zone, NW Scotland Geological Magazine, September 1, 2008; 145(5): 623 - 636. [Abstract] [Full Text] [PDF]

				J. Imber, J. IMBER, R. A. STRACHAN, R. E. HOLDSWORTH, and C. A. BUTLER The initiation and early tectonic significance of the Outer Hebrides Fault Zone, Scotland Geological Magazine, November 1, 2002; 139(6): 609 - 619. [Abstract] [Full Text] [PDF]