Reappraisal of fluid and sediment contributions to Lesser Antilles magmas

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doi: 10.1016/j.chemgeo.2009.03.030
Author(s): DuFrane, S. Andrew; Turner, Simon; Dosseto, Anthony; van Soest, Matthijs
Author Affiliation(s): Primary:
Washington State University, School of Earth and Environmental Sciences, Pullman, WA, United States
Other:
Macquarie University, Australia
Arizona State University, United States
Volume Title: Chemical Geology
Source: Chemical Geology, 265(3-4), p.272-278. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0009-2541 CODEN: CHGEAD
Note: In English. Includes appendices. 39 refs.; illus., incl. 2 tables, sketch map
Summary: We present new U-series disequilibrium and radiogenic isotope data for 7 mafic lavas from the Lesser Antilles arc. These are combined with published data in an internally consistent model that quantitatively estimates the amount of sediment and fluid added to the source of the Lesser Antilles arc system. Some lavas form an array consistent with bulk sediment addition (0.2-2%) whereas others appear to require addition of 0.4-2% sediment melt, particularly in the south of the arc. Evidence for both bulk sediment and sediment melt addition can be found within both the northern and central sections of the arc suggesting a thermal structure whereby the upper portions of the subducted sediment pile lie close to their solidus beneath much of the arc. Addition of up to 5% fluid derived from altered oceanic crust to these sediment enriched mantle wedge source regions can simulate the majority of the lavas on a plot of 207Pb/204Pb versus Ce/Pb. By taking into account the range in calculated wedge compositions and allowing for some mobility of Th in the fluid, the same model can also account for much of the observed range of U-Th-Ra disequilibria, especially if the eclogitic residue contains trace amounts of rutile. The implication of this more complex model is that the time scales for fluid addition and differentiation could be significantly shorter than those estimated in some previous studies. Abstract Copyright (2009) Elsevier, B.V.
Year of Publication: 2009
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 05 Petrology, Igneous and Metamorphic; Absolute age; Actinides; Alkaline earth metals; Antilles; Caribbean region; Chemical composition; Cretaceous; Dates; Fluid phase; Geochemistry; Igneous rocks; Island arcs; Isotope ratios; Isotopes; Lava; Lead; Lesser Antilles; Mafic composition; Magmas; Major elements; Marine sediments; Melts; Mesozoic; Metals; Models; Nd-144/Nd-143; Neodymium; North Pacific; Northwest Pacific; ODP Site 801; Ocean Drilling Program; Pacific Ocean; Pb-207/Pb-204; Pigafetta Basin; Radioactive isotopes; Radium; Rare earths; Sediments; Stable isotopes; Th/U; Thorium; Trace elements; Uranium; Uranium disequilibrium; Volcanic rocks; West Indies; West Pacific
Coordinates: N183831 N183835 E1562136 E1562134
N120000 N180000 W0610000 W0630000
Record ID: 2010032148
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands