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 |
|---|---|
| Pages (from-to) | 175-197 |
| Number of pages | 23 |
| Journal | Journal of Structural Geology |
| Volume | 126 |
| DOIs | |
| Publication status | Published - 1 Sep 2019 |
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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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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 Journal › Article › Academic › peer-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
N2 - 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.
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.
KW - Analogue modelling
KW - Basement strike-slip fault
KW - Brittle shear zone
KW - Gloria transform fault
KW - Pre-tectonic crustal viscous anomaly
KW - Shear-zone structural pattern
KW - Tore-Madeira rise tectono-magmatic interference
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UR - http://www.scopus.com/inward/citedby.url?scp=85067203207&partnerID=8YFLogxK
U2 - 10.1016/j.jsg.2019.06.004
DO - 10.1016/j.jsg.2019.06.004
M3 - Article
VL - 126
SP - 175
EP - 197
JO - Journal of Structural Geology
JF - Journal of Structural Geology
SN - 0191-8141
ER -