Skip to main content

Research Repository

Advanced Search

Overprinting orogenic events, ductile extrusion and strain partitioning during Caledonian transpression, NW Mainland Shetland

Armitage, Timothy B.; Holdsworth, Robert E.; Strachan, Robin A.; Dempsey, Edward D.; Walker, Richard J.; Alvarez-Ruiz, Diana T.; Lloyd, Geoffrey E.

Authors

Timothy B. Armitage

Robert E. Holdsworth

Robin A. Strachan

Profile image of Eddie Dempsey

Dr Eddie Dempsey E.Dempsey@hull.ac.uk
Senior Lecturer in Structural Geology and Geohazards

Richard J. Walker

Diana T. Alvarez-Ruiz

Geoffrey E. Lloyd



Abstract

A 3.6 km thick stack of mid-crustal deformed Precambrian rocks is associated with the North Roe Nappe (NRN) and Walls Boundary Fault in the northernmost Scottish Caledonides on NW Mainland Shetland. The greenschist- to amphibolite-facies rocks display unusually complex and heterogeneous combinations of coaxial and non-coaxial transpressional deformation. Previously published isotopic dating, together with new detailed field mapping and microstructural characterisation show that the NRN preserves a record of Neoarchaean, Neoproterozoic (Knoydartian) and Ordovician-Silurian (Caledonian) overprinting deformation and metamorphism. Neoarchaean events in the Uyea Gneiss Complex located in its footwall are reworked by younger events in the overlying nappe pile. The main ductile fabrics were formed during Caledonian top-to-the W/NW thrusting and top-to-the N sinistral shearing, with subordinate regions of top- to-the E extensional and NNE-SSW dextral shearing. In lower parts of the NRN, these different kinematic domains are texturally indistinguishable and overprinting relationships are absent. At higher levels, top-to-the-W/NW thrust-related fabrics are consistently overprinted by top-to-the-N/NE sinistral shearing. The highly partitioned transpressional deformation shows similarities with equivalent rocks of the Moine Nappe in NW Scotland.

Citation

Armitage, T. B., Holdsworth, R. E., Strachan, R. A., Dempsey, E. D., Walker, R. J., Alvarez-Ruiz, D. T., & Lloyd, G. E. (2024). Overprinting orogenic events, ductile extrusion and strain partitioning during Caledonian transpression, NW Mainland Shetland. Journal of Structural Geology, 180, Article 105088. https://doi.org/10.1016/j.jsg.2024.105088

Journal Article Type Article
Acceptance Date Feb 15, 2024
Online Publication Date Feb 21, 2024
Publication Date Mar 1, 2024
Deposit Date Feb 26, 2024
Publicly Available Date Mar 5, 2024
Journal Journal of Structural Geology
Print ISSN 0191-8141
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 180
Article Number 105088
DOI https://doi.org/10.1016/j.jsg.2024.105088
Keywords Transpression; Strain partitioning; Overprinting events; Quartz petrofabric analysis; EBSD
Public URL https://hull-repository.worktribe.com/output/4560989

Files




You might also like



Downloadable Citations