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Caribbean plate boundaries control on the tectonic duality in the back-arc of the Lesser Antilles subduction zone during the Eocene
- Source :
- Tectonics, Tectonics, 2021, 40 (11), pp.e2021TC006885. ⟨10.1029/2021TC006885⟩, Tectonics, American Geophysical Union (AGU), 2021, 40 (11), pp.e2021TC006885. ⟨10.1029/2021TC006885⟩, Tectonics (0278-7407) (American Geophysical Union (AGU)), 2021-11, Vol. 40, N. 11, P. e2021TC006885 (22p.)
- Publication Year :
- 2022
- Publisher :
- California Digital Library (CDL), 2022.
-
Abstract
- The Eocene tectonic evolution of the easternmost Caribbean Plate (CP) boundary, i.e. the Lesser Antilles subduction zone (LASZ), is debated. Recents works shed light on a peculiar period of tectonic duality in the arc/back-arc regions. A compressive-to-transpressive regime occurred in the north, while rifting and seafloor spreading occurred in Grenada basin to the south. The mechanism for this strong spatial variation and its evolution through time has yet to be established. Here, using 3-D subduction mechanical models, we evaluate whether the change in the trench-curvature radius at the northeast corner of the CP could have modulated the duality. We assume asymmetrical CP boundaries at the north (from east to west: oblique subduction to strike-slip) and at the south (subduction-transform edge propagator-like behavior). Regardless of the imposed trench curvature, the southern half of our modeled CP always undergoes a NWto-W-oriented extension due to the tendency of the southernmost part of the South-America slab to rollback. In contrast, the tectonic regime in the northeast corner of the CP depends on the trench-curvature radius. A low radius promotes transtension-to-transpression, with a NE-oriented compressive component of the principal stress. A high trench-curvature largely reduces the compressive component and promotes an extensive regime similar to that in the south. We thus propose that an initially low-curvature radius of the NE-LASZ triggered the tectonic N-S duality in the Eocene and led to an ephemeral period of transpression/compression at the north, although an additional mechanism might have been required to locally enhance compression
- Subjects :
- Back-arc tectonic regime
010504 meteorology & atmospheric sciences
lesser antilles subduction zone
Subduction dynamics
010502 geochemistry & geophysics
Geodynamics
01 natural sciences
Transpression
back-arc tectonic regime
Paleontology
Geochemistry and Petrology
Compression (geology)
0105 earth and related environmental sciences
trench curvature
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics
Rift
Subduction
Seafloor spreading
Plate tectonics
Tectonics
Geophysics
numerical modeling
13. Climate action
Caribbean plate
Lesser Antilles Subduction Zone
subduction
Geology
Subjects
Details
- ISSN :
- 02787407 and 19449194
- Database :
- OpenAIRE
- Journal :
- Tectonics, Tectonics, 2021, 40 (11), pp.e2021TC006885. ⟨10.1029/2021TC006885⟩, Tectonics, American Geophysical Union (AGU), 2021, 40 (11), pp.e2021TC006885. ⟨10.1029/2021TC006885⟩, Tectonics (0278-7407) (American Geophysical Union (AGU)), 2021-11, Vol. 40, N. 11, P. e2021TC006885 (22p.)
- Accession number :
- edsair.doi.dedup.....31bfe5c2a2b15755a5c25316240a2c14