Origin of the volcanic complexes of La Désirade, Lesser Antilles: implications for tectonic reconstruction of the Late Jurassic to Cretaceous Pacific-proto Caribbean margin

Neill, Iain, Gibbs, Jennifer A., Hastie, Alan R. and Kerr, Andrew Craig ORCID: https://orcid.org/0000-0001-5569-4730 2010. Origin of the volcanic complexes of La Désirade, Lesser Antilles: implications for tectonic reconstruction of the Late Jurassic to Cretaceous Pacific-proto Caribbean margin. Lithos 120 (3-4) , pp. 407-420. 10.1016/j.lithos.2010.08.026

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Abstract

La Désirade Island is located on the hanging wall of the present-day Lesser Antilles subduction zone and consists of a suite of Mesozoic igneous rocks capped by Neogene limestone. The basement suite contains Kimmeridgian to Tithonian (~153–145 Ma) mafic lava flows and pillow basalts overlain by felsic flows and breccias and intruded by a Mid-Berriasian (~144 Ma) trondhjemite pluton and intermediate to felsic dykes. The mafic rocks form a ~300 m thick sequence which trace element geochemistry reveals to contain, in stratigraphic order: (1) tholeiites with a very weak subduction signature; (2) calc-alkaline and tholeiitic arc rocks containing pelagic and terrigenous sediment slab-related components and (3) arc tholeiites with a minor subduction signature. The mantle wedge source was depleted and did not contain a significant plumerelated component. The overlying felsic rocks show similar trace element patterns and incompatible trace element ratios to the mafic units. Factors such as pelagic sedimentary deposition and re-working, low eruption rates and the presence of MORB-like and felsic rocks are best explained by an origin at a back-arc spreading ridge. This back-arc was most likely in the proto-Caribbean (Colombian Marginal) seaway and was related to east-dipping Andean/Cordilleran subduction. Other sites in the Greater Antilles and Central America older than the ~135 Ma westward acceleration of North America appear to corroborate a latest Jurassic–Early Cretaceous east-dipping arc system. The preservation of La Désirade in the fore-arc of the present Antilles arc is consistent with Mid-to-Late Cretaceous inception of west-dipping subduction along the former back-arc axis which had previously given rise to La Désirade.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Subjects:	Q Science > QE Geology
Uncontrolled Keywords:	La Désirade ; Caribbean ; Geochemistry ; Tectonics ; Subduction.
Publisher:	Elsevier
ISSN:	0024-4937
Last Modified:	18 Oct 2022 12:21
URI:	https://orca.cardiff.ac.uk/id/eprint/9559

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