Séminaire ISTeP - Osamu Ishizuka

(AIST, Tsukuba, Japon; Professeur invité à l'ISTeP)

IODP Expedition 351 Izu-Bonin-Mariana Arc Origins: preliminary results

Understanding how subduction zones are initiated and continental crust forms in intraoceanic arcs requires knowledge of the inception and evolution of a representative intraoceanic arc, such as the Izu-Bonin-Mariana arc system. This can be obtained by identification and exploration of regions adjacent to an arc, where unequivocally pre-arc crust (basement) overlain by undisturbed arc-derived materials exists. IODP (International Ocean Discovery Program) Exp.351 targeted, in particular, evidence for the earliest evolution of the Izu-Bonin-Mariana arc system following inception.
Exp.351 successfully recovered pre-Izu-Bonin-Mariana arc basement, a volcanic and geologic record spanning pre-Arc, arc initiation to remnant arc stages permitting hypothesis testing for subduction initiation and subsequent Arc evolution. I will introduce scientific background and targets of this expedition, and present on-board and some of the first shore-based results from this expedition.
References: Ishizuka et al. (2014) Elements, 10, 115-120; Arculus et al. (2015) Nature Geoscience, 8, 728-733.

13/11/2015 à 12h30, Salle Fourcade (Tour 55-56, 4ème étage)