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

Research output: Contribution to JournalArticleAcademicpeer-review

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
DOIs
Publication statusPublished - 1 Sep 2019

Fingerprint

shear zone
perturbation
submarine ridge
modeling
transform fault
strike-slip fault
salt
anomaly
tectonics
sand
experiment
comparison
effect

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

Cite this

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title = "Analogue modelling of brittle shear zone propagation across upper crustal morpho-rheological heterogeneities",
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.",
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author = "Gomes, {A. S.} and Rosas, {F. M.} and Duarte, {J. C.} and Schellart, {W. P.} and J. Almeida and R. Tom{\'a}s and V. Strak",
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Analogue modelling of brittle shear zone propagation across upper crustal morpho-rheological heterogeneities. / Gomes, A. S.; Rosas, F. M.; Duarte, J. C.; Schellart, W. P.; Almeida, J.; Tomás, R.; Strak, V.

In: Journal of Structural Geology, Vol. 126, 01.09.2019, p. 175-197.

Research output: Contribution to JournalArticleAcademicpeer-review

TY - JOUR

T1 - Analogue modelling of brittle shear zone propagation across upper crustal morpho-rheological heterogeneities

AU - Gomes, A. S.

AU - Rosas, F. M.

AU - Duarte, J. C.

AU - Schellart, W. P.

AU - Almeida, J.

AU - Tomás, R.

AU - Strak, V.

PY - 2019/9/1

Y1 - 2019/9/1

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AB - 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.

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