Subduction Initiation and Ophiolite Crust: New Insights from IODP Drilling
zu, bonin, boninite, basalt, drilling, International Ocean Discovery Program, Expedition 352, Site U1439, Site U1440, Site U1441, Site U1442, ophiolite, subduction initiation, Philippine plate
Digital Object Identifier (DOI)
International 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.
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Citation / Publisher Attribution
International Geology Review, v. 59, issue 11, p. 1439-1450
Scholar Commons Citation
Reagan, Mark K.; Pearce, Julian A.; Petronotis, Katerina; Almeev, Renat R.; Avery, Aaron J.; Carvallo, Claire; and Ryan, Jeffrey G., "Subduction Initiation and Ophiolite Crust: New Insights from IODP Drilling" (2017). School of Geosciences Faculty and Staff Publications. 1139.