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Variation in upper plate crustal and lithospheric mantle structure in the greater and lesser antilles from ambient noise tomography

Variation in upper plate crustal and lithospheric mantle structure in the greater and lesser antilles from ambient noise tomography
Variation in upper plate crustal and lithospheric mantle structure in the greater and lesser antilles from ambient noise tomography
The crust and upper mantle structure of the Greater and Lesser Antilles Arc provides insights into key subduction zone processes in a unique region of slow convergence of old slow-spreading oceanic lithosphere. We use ambient noise tomography gathered from island broadband seismic stations and the temporary ocean bottom seismometer network installed as part of the Volatile Recycling in the Lesser Antilles experiment to map crustal and upper mantle shear-wave velocity of the eastern Greater Antilles and the Lesser Antilles Arc. Taking the depth to the 2.0 km/s contour as a proxy, we find sediment thickness up to 15 km in the south in the Grenada and Tobago basins and thinner sediments near the arc and to the north. We observe thicker crust, based on the depth to the 4.0 km/s velocity contour, beneath the arc platforms with the greatest crustal thickness of around 30 km, likely related to crustal addition from arc volcanism through time. There are distinct low velocity zones (4.2–4.4 km/s) in the mantle wedge (30–50 km depth), beneath the Mona Passage, Guadeloupe-Martinique, and the Grenadines. The Mona passage mantle anomaly may be related to ongoing extension there, while the Guadeloupe-Martinique and Grenadine anomalies are likely related to fluid flux, upwelling, and/or partial melt related to nearby slab features. The location of the Guadeloupe-Martinique anomaly is slightly to the south of the obliquely subducted fracture zones. This feature could be explained by either three-dimensional mantle flow, a gap in the slab, variable slab hydration, and/or melt dynamics including ponding and interactions with the upper plate.
Ambient noise tomography, Lesser Antilles Arc, OBS network, Sediment thickness variation, Crustal thickness variation, Lithospheric mantle structure
1525-2027
Schlaphorst, D.
ce763c91-8236-4eac-b256-b35a8613d62b
Harmon, N.
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Kendall, J.M.
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Rychert, C.A.
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Collier, J.
fc47f422-9693-431e-90cc-da75c4e6bedb
Rietbrock, A.
e4656f22-06be-40fe-8f98-7f88c351c434
Goes, S.
7a2932d0-4492-47b2-9cbb-9d4a8b377360
Schlaphorst, D.
ce763c91-8236-4eac-b256-b35a8613d62b
Harmon, N.
10d11a16-b8b0-4132-9354-652e72d8e830
Kendall, J.M.
30b320d4-4100-4bbc-9026-67caeccce30d
Rychert, C.A.
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Collier, J.
fc47f422-9693-431e-90cc-da75c4e6bedb
Rietbrock, A.
e4656f22-06be-40fe-8f98-7f88c351c434
Goes, S.
7a2932d0-4492-47b2-9cbb-9d4a8b377360

Schlaphorst, D., Harmon, N., Kendall, J.M., Rychert, C.A., Collier, J., Rietbrock, A. and Goes, S. (2021) Variation in upper plate crustal and lithospheric mantle structure in the greater and lesser antilles from ambient noise tomography. Geochemistry, Geophysics, Geosystems, 22 (7), [e2021GC009800]. (doi:10.1029/2021GC009800).

Record type: Article

Abstract

The crust and upper mantle structure of the Greater and Lesser Antilles Arc provides insights into key subduction zone processes in a unique region of slow convergence of old slow-spreading oceanic lithosphere. We use ambient noise tomography gathered from island broadband seismic stations and the temporary ocean bottom seismometer network installed as part of the Volatile Recycling in the Lesser Antilles experiment to map crustal and upper mantle shear-wave velocity of the eastern Greater Antilles and the Lesser Antilles Arc. Taking the depth to the 2.0 km/s contour as a proxy, we find sediment thickness up to 15 km in the south in the Grenada and Tobago basins and thinner sediments near the arc and to the north. We observe thicker crust, based on the depth to the 4.0 km/s velocity contour, beneath the arc platforms with the greatest crustal thickness of around 30 km, likely related to crustal addition from arc volcanism through time. There are distinct low velocity zones (4.2–4.4 km/s) in the mantle wedge (30–50 km depth), beneath the Mona Passage, Guadeloupe-Martinique, and the Grenadines. The Mona passage mantle anomaly may be related to ongoing extension there, while the Guadeloupe-Martinique and Grenadine anomalies are likely related to fluid flux, upwelling, and/or partial melt related to nearby slab features. The location of the Guadeloupe-Martinique anomaly is slightly to the south of the obliquely subducted fracture zones. This feature could be explained by either three-dimensional mantle flow, a gap in the slab, variable slab hydration, and/or melt dynamics including ponding and interactions with the upper plate.

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Accepted/In Press date: 21 June 2021
Published date: 25 June 2021
Additional Information: https://doi.org/10.1029/2021GC009800
Keywords: Ambient noise tomography, Lesser Antilles Arc, OBS network, Sediment thickness variation, Crustal thickness variation, Lithospheric mantle structure

Identifiers

Local EPrints ID: 450327
URI: http://eprints.soton.ac.uk/id/eprint/450327
ISSN: 1525-2027
PURE UUID: 13b30877-34c8-4a39-aa97-ad7cc0f37dc0
ORCID for N. Harmon: ORCID iD orcid.org/0000-0002-0731-768X

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Date deposited: 23 Jul 2021 16:30
Last modified: 27 Aug 2021 01:40

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Contributors

Author: D. Schlaphorst
Author: N. Harmon ORCID iD
Author: J.M. Kendall
Author: C.A. Rychert
Author: J. Collier
Author: A. Rietbrock
Author: S. Goes

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