Fault patterns generated during extensional deformation of crystalline basement, NW Scotland
- 1 January 1987
- journal article
- Published by Geological Society of London in Geological Society, London, Special Publications
- Vol. 28 (1) , 495-499
- https://doi.org/10.1144/gsl.sp.1987.028.01.31
Abstract
Summary: The fracture array in the Lewisian basement of NW Scotland is dominated by two orthogonal sets. Parallel to and perhaps in part reactivating these fractures are two sets of faults, each with apparent normal offset. The NE-trending faults are longer and regionally more significant. The NW-trending faults commonly terminate against NE-trending faults and divide the hanging wall rocks of NE-trending faults into independent blocks. The propagation of principal NE-trending faults into the basement was accommodated discontinuously by relative differential displacement of these crustal blocks. The limited data suggest that incremental slip episodes were down-dip and coaxial on the NE-trending faults, but not on the NW-trending faults. The presence of non-coaxial low-angle slip lineations on NW-trending faults suggests either that master NE-trending faults rotated during progressive deformation, or that the dip of these faults decreases with depth. The dominance of NE-trending faults, and the kinematics of fault movements suggest that movement on the faults accommodated NW-SE extension.Keywords
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