Variation in upper plate crustal and lithospheric mantle structure in the Greater and Lesser Antilles from ambient noise tomography

Schlaphorst, D., Harmon, N., Kendall, J. M., Rychert, C. A., Collier, J., Rietbrock, A. and Goes, S. and the VoiLA team (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). ISSN 1525-2027

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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.

Item Type: Article
Additional Information: Acknowledgements: The authors would like to thank Tim Greenfield and Joshua Russel for their constructive comments and suggestions. This research was funded by the VoiLA NERC consortium grant (NE/K010824/1). The authors thank all who sailed on cruises RRS James Cook JC133 and JC149. The authors thank our partners at the University of West Indies Seismic Research Centre (SRC), in particular Lloyd Lynch, Kemron Alexander, Richard Robertson and Joan Latchman as well as Laura Petrescu and Ben Chichester for support with island station installation, the German Instrument Pool for Amphibian Seismology (DEPAS), hosted by the Alfred Wegener Institute Bremerhaven for providing the ocean‐bottom and temporary island seismometers, and UCSD (Scripps) for providing additional ocean‐bottom seismometers. D. Schlaphorst would like to acknowledge the financial support FCT through project SIGHT (Ref. PTDC/CTA‐GEF/30264/2017) and UIDB/50019/2020—IDL.
Uncontrolled Keywords: ambient noise tomography,crustal thickness variation,lesser antilles arc,lithospheric mantle structure,obs network,sediment thickness variation,geophysics,geochemistry and petrology ,/dk/atira/pure/subjectarea/asjc/1900/1908
Faculty \ School: Faculty of Science > School of Environmental Sciences
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Depositing User: LivePure Connector
Date Deposited: 25 Apr 2022 09:31
Last Modified: 11 Oct 2023 01:14
DOI: 10.1029/2021GC009800


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