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Sedimentary input to the source of Lesser Antilles lavas: A Li perspective

Sedimentary input to the source of Lesser Antilles lavas: A Li perspective. Ming Tang 1 , Roberta Rudnick 1 , Catherine Chauvel 2 Department of Geology, University of Maryland Universite ´ Grenoble Alpes. Ming Tang. Fang-Zhen Teng. Mt. Pelée , Martinque.

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Sedimentary input to the source of Lesser Antilles lavas: A Li perspective

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  1. Sedimentary input to the source of Lesser Antilles lavas: A Li perspective Ming Tang1, Roberta Rudnick1, Catherine Chauvel2 Department of Geology, University of Maryland Universite´ Grenoble Alpes Ming Tang Fang-Zhen Teng Mt. Pelée, Martinque

  2. Can Li be used to trace recycling? What do arc lavas tell us? altered MORB +3 to +14 serpentinite- decollement island arc diapir sediments fluid km +20 -5 to +15 +20 0 forearc 30 +4 mantle 60 eclogite ~+4 d7Li -11 to +4 0 to +4* 90 120 *Marschall et al. (2007) After Zack et al., 2003, EPSL

  3. Most arcs = MORB (maybe a bit heavier) Global Arc Lavas

  4. Mantle Retention of Lithium? OUT: fluids with slab B, but little Li IN: fluids with slab Li & B From Tomascak et al. (EPSL,2002)

  5. The case for subducted sediments in the Lesser Antilles lavas Sediments +10 +5 0 -5 -10 -15 -20 Labanieh et al., 2012, J. Petrol.

  6. Global Subducting Sediments Site 543 Bouman et al., 2004 Averages from Plank, 2014, TOG

  7. Our Project: • Analyze d7Li in • subducting sediments • Martinque lavas • Do we see the sedimentary signature reappearing in the lavas? Mt. Pelée, Martinque

  8. SubductingSediments Mt. Pelée, Martinque Tang et al., 2014, following Plank, 2014

  9. Lesser Antilles subducting sediments are global end member Lesser Antilles subducting sediments areclearly much lighter than mantle Mt. Pelée, Martinque Tang et al., 2014, GCA

  10. Martinique lavas Li clearly influenced by sedimentary input Submarine eruption – interaction with seawater Tang et al., 2014, GCA

  11. No evidence for crustal assimilation: sediments added to mantle source Tang et al., 2014, GCA

  12. Mixing scenarios Mt. Pelée, Martinque

  13. Conclusions • Li can make it through the mantle wedge! • Clear subductedterrigneous sediment signature in Martinque lavas • Probably added through melts of sediments

  14. Congratulations Fang-Zhen!

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