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Extending La Reunion Island volcanic record to the Mid-Pleistocene: Insights from deep-sea sediments and tephrostratigraphic analysis

Elodie Lebas 1, Steffen Kutterolf2, Anne Le Friant1, Julie Christin Schindlbeck-Belo2, Jean-Guillaume Feignon3, Kai Fockenberg2, Stephan Jorry4, Patrick Bachèlery5, Nathalie Babonneau4

  • Affiliations: 1Université Paris Cité, Institut de Physique du Globe de Paris, 1 rue Jussieu, 75005 Paris, France; 2GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, D-24148 Kiel, Germany; 3Archaeology, Environmental Changes, & Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium; 4Geo-Ocean, UMR 6538, Univ. Brest, CNRS, Ifremer, Brest, France; 5Université Clermont-Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, 6 avenue Blaise Pascal, 63178 Aubière, France 

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 152

  • Programme No: 3.13.20

  • Theme 3 > Session 13

Abstract

La Reunion Island (western Indian Ocean) is an intraplate volcanic system composed of two shield volcanoes: the extinct Piton des Neiges and the still-active Piton de la Fournaise. During the expedition ERODER4 (2011; doi:10.17600/11200040), approximately 130 meters of marine sediments were recovered to investigate five large volcaniclastic turbidite systems. A 16.74 m-long core (MD11-3347) stood out, as it aimed to reconstruct the past volcanic activity of La Reunion and was hence retrieved on a higher plateau (2890 mbsl) on Piton des Neiges northern flank.  Oxygen isotope measurements of planktonic foraminifera (Globigerinoides Ruber) indicate an age of 433 ka at the core base, representing the oldest sedimentary archive available offshore La Reunion. A comprehensive sedimentological and volcanological study was performed. Magnetic susceptibility data suggests that 39 horizons could have been derived from explosive eruptions. We further investigated these horizons by acquiring extensive major and trace element analyses on glass shards and pumiceous fragments. Altogether, our study aims at identifying distal deposits from previously known and unknown large (paleo-)volcanic events; assigning these deposits to on-land volcanic centers using geochemical fingerprinting; investigating temporal and geochemical changes of these events; to finally establish a compositional and temporal tephrostratigraphic framework for the region around La Reunion. Here, we report on the first results of this tephrochronostratigraphic study, primarily based on major element chemistry, which identify mugearitic to trachytic volcanic events in the oldest part of the MD11-3347 core.