Analogue modelling of brittle shear zone propagation across upper crustal morpho-rheological heterogeneities

A. S. Gomes, F. M. Rosas*, J. C. Duarte, W. P. Schellart, J. Almeida, R. Tomás, V. Strak

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

16 Downloads (Pure)

Abstract

Crustal shearing of pre-tectonic weak bodies (e.g. salt pillows, igneous pockets) associated with basement strike-slip fault systems is common in nature. Yet the structural pattern arising from the interference between a brittle shear zone and such weak rheological heterogeneities is still not fully explained. In the present work, different sand-box analogue modelling experiments were carried out to better understand, not only the shear zone perturbation effect caused by a strictly rheologic (viscous-weak) anomaly, but also the one arising from a combined morphological perturbation (i.e. traverse topographic crest). Obtained results show that the development of different shear zone deformation patterns is in each case essentially determined by the interplay between: (i) ductile wrenching strain accommodation in the (viscous) weak body; and (ii) coincidence vs. mismatch between main brittle-viscous rheological boundaries and (crest-related) topographic steps. Comparison of the experimentally obtained results with complying natural examples is further discussed, and essentially focused on the NE Atlantic tectono-magmatic interference between the Gloria transform fault and the Tore-Madeira submarine ridge.

Original languageEnglish
Pages (from-to)175-197
Number of pages23
JournalJournal of Structural Geology
Volume126
Early online date7 Jun 2019
DOIs
Publication statusPublished - Sept 2019

Funding

This work was sponsored by the Fundação para a Ciência e a Tecnologia through project UID/GEO/50019/2019-IDL and project SPIDER - PTDC/GEO-FIQ/2590/2014 . JCD acknowledges an FCT Researcher contract and an exploratory project (grant ref. IF/00702/2015 ). Jaime Almeida acknowledges a Ph.D. grant by Lisbon Earth-Systems Doctoral School ref: PD/BD/135067/2017 . A. Simões and M. Roque are acknowledged for helping with lab work. We thank Tim Dooley and Clint Conrad for their thorough constructive revision of the original manuscript. Appendix B

FundersFunder number
Fundação para a Ciência e a TecnologiaUID/GEO/50019/2019-IDL
Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e NeuroproteçãoPTDC/GEO-FIQ/2590/2014
Fundació Catalana de TrasplantamentIF/00702/2015, PD/BD/135067/2017

    Keywords

    • Analogue modelling
    • Basement strike-slip fault
    • Brittle shear zone
    • Gloria transform fault
    • Pre-tectonic crustal viscous anomaly
    • Shear-zone structural pattern
    • Tore-Madeira rise tectono-magmatic interference

    Fingerprint

    Dive into the research topics of 'Analogue modelling of brittle shear zone propagation across upper crustal morpho-rheological heterogeneities'. Together they form a unique fingerprint.

    Cite this