- Subduction initiation and ophiolite crust: new insights from IODP drilling doi link

Auteur(s): Reagan Mark k., Pearce Julian a., Petronotis Katerina, Almeev Renat r., Avery Aaron j., Carvallo Claire, Chapman Timothy, Christeson Gail l., Ferre Eric c., Godard M., Heaton Daniel e., Kirchenbaur Maria, Kurz Walter, Kutterolf Steffen, Li Hongyan, Li Yibing, Michibayashi Katsuyoshi, Morgan Sally, Nelson Wendy r., Prytulak Julie, Python Marie, Robertson Alastair h. f., Ryan Jeffrey g., Sager William w., Sakuyama Tetsuya, Shervais John w., Shimizu Kenji, Whattam Scott a.

(Article) Publié: International Geology Review, vol. 59 p.1439-1450 (2017)

DOI: 10.1080/00206814.2016.1276482

nternational Ocean Discovery Program (IODP) Expedition 352 recovered a high-fidelity record of volcanism related to subduction initiation in the Bonin fore-arc. Two sites (U1440 and U1441) located in deep water nearer to the trench recovered basalts and related rocks; two sites (U1439 and U1442) located in shallower water further from the trench recovered boninites and related rocks. Drilling in both areas ended in dolerites inferred to be sheeted intrusive rocks. The basalts apparently erupted immediately after subduction initiation and have compositions similar to those of the most depleted basalts generated by rapid sea-floor spreading at mid-ocean ridges, with little or no slab input. Subsequent melting to generate boninites involved more depleted mantle and hotter and deeper subducted components as subduction progressed and volcanism migrated away from the trench. This volcanic sequence is akin to that recorded by many ophiolites, supporting a direct link between subduction initiation, fore-arc spreading, and ophiolite genesis.