Geochemical evolution of St. Kitts and Montserrat, Lesser Antilles

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doi: 10.1144/gsjgs.141.3.0401
Authors:Baker, P. E.
Author Affiliations:Primary:
Univ. Nottingham, Dep. Geol., Nottingham, United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.141(Part 3), p.401-410. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1984
Note:In English. 19 refs.Subduction-related magmatism; illus. incl. 2 tables, geol. sketch maps
Summary:The volcanic rocks of St. Kitts have uniform 87Sr/86Sr ratios (approx 0.7037) and high 143Nd/144Nd ratios (approx 0.5310) in a suite ranging from basalt to rhyolite. Trace-element abundances (major and trace elements are given for 20 rocks) and flat normalized REE patterns resemble those of island-arc tholeiitic suites. In comparison the lavas of Montserrat are richer in alkalis and in LREE. Geochemical differences may be related to partial displacement of the axis of the volcanic arc approx 9 m.y. ago, leading to the development of St. Kitts' suite in an essentially new and immature island-arc environment, whereas the Montserrat lavas may reflect earlier subduction-related mantle enrichment and/or the influence of a sedimentary component. Basalt from Redonda (between the other two islands) has a high Sr content and is LREE-enriched; Redonda is on the main axis of the volcanic arc and its lavas are contemporaneous with the younger eruptions of St. Kitts and Montserrat. [R.A.H.]
Subjects:Alkalic composition; Alkaline earth metals; Basalts; Geochemistry; Igneous rocks; Island arcs; Isotopes; Lava; Metals; Nd-144/Nd-143; Neodymium; Petrology; Rare earths; Rhyolites; Sr-87/Sr-86; Stable isotopes; Strontium; Tholeiite; Trace elements; Volcanic rocks; Antilles; Caribbean region; Lesser Antilles; Montserrat Island; Saint Kitts; West Indies; Ratios; Redonda; Saint Kitts Suite
Coordinates:N164500 N172000 W0621000 W0624500
Abstract Numbers:84M/4132
Record ID:1985081094
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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