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 language | English |
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Pages (from-to) | 175-197 |
Number of pages | 23 |
Journal | Journal of Structural Geology |
Volume | 126 |
Early online date | 7 Jun 2019 |
DOIs | |
Publication status | Published - 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
Funders | Funder number |
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Fundação para a Ciência e a Tecnologia | UID/GEO/50019/2019-IDL |
Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção | PTDC/GEO-FIQ/2590/2014 |
Fundació Catalana de Trasplantament | IF/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