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, I. , Gibbs, J. A., Hastie, A. R. and Kerr, A. C. (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. (doi:10.1016/j.lithos.2010.08.026)

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Publisher's URL: http://dx.doi.org/10.1016/j.lithos.2010.08.026

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 plume-related 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:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Neill, Dr Iain
Authors: Neill, I., Gibbs, J. A., Hastie, A. R., and Kerr, A. C.
Subjects:Q Science > QE Geology
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Lithos
Publisher:Elsevier BV
ISSN:0024-4937
ISSN (Online):1872-6143

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