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Deep crustal structure and tectonic origin of the Tobago-Barbados Ridge

Shenelle Gomez, Dale Bird and Paul Mann
Deep crustal structure and tectonic origin of the Tobago-Barbados Ridge
Interpretation (Tulsa) (May 2018) 6 (2): T471-T484

Abstract

The north-south-trending Tobago-Barbados ridge (TBR) extends 250 km from its southern end at the island of Tobago to its northern end at the island of Barbados. On Tobago, exposed metasedimentary and metaigneous rocks have been identified as fragments of a Mesozoic primitive island arc, whereas on Barbados, exposed sedimentary rocks record Paleogene development of the Barbados accretionary prism (BAP). We integrate gravity data with seismic refraction data, well constraints, and seismic reflection data to improve our understanding of the TBR's crustal structure, uplift mechanism, along-strike compositional variations in the crust, and tectonic origin. Three 2D gravity models suggest that the TBR is underlain by a "pop-up" crustal block uplifted in the trench between the overriding Caribbean plate and the westwardly subducting South American plate. At approximately 11.75 degrees N, the character of the TBR changes over a distance of 60 km from a symmetrical and more elevated, crystalline, thrust fault-bounded structure to a west-verging thrust belt that is less elevated. The symmetrical pop-up and asymmetrical, west-verging thrust belt accommodate east-west, subduction-related shortening that deforms the westernmost edge of the BAP. We think that the crystalline basement of the southern and central TBR is the buried, northeastern continuation of Mesozoic intraoceanic-arc crust and metamorphic belt of Tobago that accreted along the eastern margin of the Great Arc of the Caribbean during its subduction polarity reversal in the early Cretaceous.


ISSN: 2324-8858
EISSN: 2324-8866
Serial Title: Interpretation (Tulsa)
Serial Volume: 6
Serial Issue: 2
Title: Deep crustal structure and tectonic origin of the Tobago-Barbados Ridge
Affiliation: University of Houston, Department of Earth and Atmospheric Sciences, Houston, TX, United States
Pages: T471-T484
Published: 201805
Text Language: English
Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States
References: 66
Accession Number: 2019-006814
Categories: Solid-earth geophysicsApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: block diag., sects., strat. cols., geol. sketch maps
N10°00'00" - N15°00'00", W64°00'00" - W58°00'00"
Secondary Affiliation: Bird Geophysical, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute.
Update Code: 201906
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