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Marine tephrostratigraphy in the Sunda Strait (Indonesia)

Julie C. Schindlbeck-Belo1, Katharina Pank1, Morelia Urlaub1, Thor H. Hansteen1, Jan Fietzke1, Andreas Lückge2, Frank Melcher3, Steffen Kutterolf1

  • Affiliations: 1GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany 2Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany  3Department Applied Geosciences and Geophysics, Montanuniversität Leoben, Leoben, Austria

  • Presentation type: Poster

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

  • Poster Board Number: 139

  • Programme No: 3.13.8

  • Theme 3 > Session 13

Abstract

Krakatau volcano in the Sunda strait is famously infamous for its 1883 eruption, which represents one of the largest explosive and climate-changing eruptions in historic times (Sigurdsson et al., 1991). However, very little is known about the pre-1883 explosive eruptive history of Krakatau.  Drill core data suggests an eruption in the Sunda Strait at ca. 60 ka BP, but it remains uncertain if this eruption originated from Krakatau volcano (Ninkovich, 1979). We therefore reinvestigated 9 marine gravity cores from two RV SONNE cruises. Expedition SO139 recovered two cores ~120 km SE of Sumatra in the Sunda fore-arc basin (cores SO139-74 KL and SO139-50KL), and the recent  SO299/2 expedition recovered sediment cores in the vicinity of the Krakatau caldera (SO299/2-GC2 to GC9). The sediments in the distal coring sites (SO139) go back to ~300 and 560 ka, and contain multiple tephra layers orginating from explosive eruptions of the Sunda arc area. The sediments recovered in the proximal cores (SO299/2) are probably limited to historical times. We applied geochemical finger-printing on volcanic glass shards using major and trace element compositions to unravel the provenance of the various marine tephra layers. The glass shard compositions from tephra layers in SO139 cores range from basaltic-trachy-andesite to rhyolite, indicating different volcanic sources with varying eruption frequencies over time, whereas the tephra layers in SO299/2 cores contain glass shard compositions from andesite to rhyolite, mainly featuring compositions known from the 1883 Krakatau eruption, as well as historical Anak Krakatau eruptions.