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Published bySybil Gardner Modified over 9 years ago
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Sedimentary input to the source of Lesser Antilles lavas: A Li perspective Ming Tang 1, Roberta Rudnick 1, Catherine Chauvel 2 1.Department of Geology, University of Maryland 2.Universite´ Grenoble Alpes Mt. Pelée, Martinque Fang-Zhen Teng Ming Tang
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mantle altered MORB serpentinite- diapir ~+4 -11 to +4 0 to +4* +20 +4 +3 to +14 +20 forearc decollement island arc fluid 0 30 60 90 120 km Can Li be used to trace recycling? After Zack et al., 2003, EPSL eclogite 7 Li *Marschall et al. (2007) sediments -5 to +15 What do arc lavas tell us?
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Most arcs = MORB (maybe a bit heavier) Global Arc Lavas
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IN: fluids with slab Li & B OUT: fluids with slab B, but little Li Mantle Retention of Lithium? From Tomascak et al. (EPSL,2002)
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Labanieh et al., 2012, J. Petrol. The case for subducted sediments in the Lesser Antilles lavas Sediments +10 +5 0 -5 -10 -15 -20
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Global Subducting Sediments Site 543 Bouman et al., 2004 Averages from Plank, 2014, TOG
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Our Project: Analyze 7 Li in subducting sediments Martinque lavas Do we see the sedimentary signature reappearing in the lavas? Mt. Pelée, Martinque
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Tang et al., 2014, following Plank, 2014 Subducting Sediments
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Mt. Pelée, Martinque Lesser Antilles subducting sediments are global end member Tang et al., 2014, GCA Lesser Antilles subducting sediments are clearly much lighter than mantle
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Tang et al., 2014, GCA Submarine eruption – interaction with seawater Martinique lavas Li clearly influenced by sedimentary input
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Tang et al., 2014, GCA No evidence for crustal assimilation: sediments added to mantle source
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Mt. Pelée, Martinque Mixing scenarios
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Conclusions Li can make it through the mantle wedge! Clear subducted terrigneous sediment signature in Martinque lavas Probably added through melts of sediments
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Congratulations Fang-Zhen!
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