The movement history and fault rock evolution of a reactivated crustal-scale strike-slip fault: the Walls Boundary Fault Zone,
Shetland
L.M. Watts
R.E. Holdsworth
J.A. Sleight
R.A. Strachan
S.A.F. Smith
10.6084/m9.figshare.3454448.v1
https://geolsoc.figshare.com/articles/journal_contribution/The_movement_history_and_fault_rock_evolution_of_a_reactivated_crustal-scale_strike-slip_fault_the_Walls_Boundary_Fault_Zone___Shetland/3454448
<p>The Walls Boundary Fault Zone is a crustal-scale strike-slip fault that cuts Precambrian–Caledonian basement terranes in Shetland
and has been interpreted as the northern continuation of the Great Glen Fault Zone in Scotland. This paper presents the first
detailed account of the kinematic history and fault rock assemblages associated with the onshore evolution of the Walls Boundary
Fault Zone. These observations suggest that it initiated as a major late Caledonian (Silurian–Devonian) sinistral strike-slip
fault associated with the successive development of mylonites and cataclasites. These fault rocks are preserved only locally,
and elsewhere are obscured by the effects of later brittle overprinting and dismemberment of the fault zone during dextral
strike-slip reactivation, probably during late Carboniferous inversion of the Orcadian Basin. This led to the development
of extensive cataclasite and fault gouge assemblages, which are widely preserved along the Walls Boundary Fault. Narrow zones
of post-Triassic dip-slip, and finally sinistral strike-slip, reactivation are localized within earlier-formed gouge-filled
fault cores. There are some similarities to the kinematic history of the Great Glen Fault Zone, most notably the recognition
of late Caledonian sinistral shear and post-Devonian dextral reactivation, but the post-Triassic reactivation histories appear
to differ significantly.
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2016-06-21 12:07:30
kinematic history
Walls Boundary Fault Zone
Great Glen Fault Zone
Caledonian sinistral shear
fault rock evolution
reactivation
Walls Boundary Fault
fault rock assemblages
Geology