Petrology and Geochemistry of West Philippine Basin Basalts and Early Palau–Kyushu Arc Volcanic Clasts from ODP Leg 195, Site 1201D: Implications for the Early History of the Izu–Bonin–Mariana Arc

Authors

Ivan P. Savov, University of South FloridaFollow
Rosemary Hickey-Vargas, Florida International University
Massimo D'Antonio, University of Naples Federico II
Jeffrey G. Ryan, University of South FloridaFollow
Piera Spadea, University of Udine

Document Type

Article

Publication Date

2-2006

Keywords

back-arc basalts, Izu–Bonin–Marianas, Philippine Sea, subduction initiation, Ocean Drilling Program Leg 195

Digital Object Identifier (DOI)

https://doi.org/10.1093/petrology/egi075

Abstract

Site 1201D of Ocean Drilling Program Leg 195 recovered basaltic and volcaniclastic units from the West Philippine Basin that document the earliest history of the Izu–Bonin–Mariana convergent margin. The stratigraphic section recovered at Site 1201D includes 90 m of pillow basalts, representing the West Philippine Basin basement, overlain by 459 m of volcaniclastic turbidites that formed from detritus shed from the Eocene–Oligocene proto-Izu–Bonin–Mariana island arc. Basement basalts are normal mid-ocean ridge basalt (N-MORB), based on their abundances of immobile trace elements, although fluid-mobile elements are enriched, similar to back-arc basin basalts (BABB). Sr, Nd, Pb and Hf isotopic compositions of the basement basalts are similar to those of basalts from other West Philippine Basin locations, and show an overall Indian Ocean MORB signature, marked by high ²⁰⁸Pb/²⁰⁴Pb for a given ²⁰⁶Pb/²⁰⁴Pb and high ¹⁷⁶Hf/¹⁷⁷Hf for a given ¹⁴³Nd/¹⁴⁴Nd. Trace element and isotopic differences between the basement and overlying arc-derived volcaniclastics are best explained by the addition of subducted sediment or sediment melt, together with hydrous fluids from subducted oceanic crust, into the mantle source of the arc lavas. In contrast to tectonic models suggesting that a mantle hotspot was a source of heat for the early Izu–Bonin–Mariana arc magmatism, the geochemical data do not support an enriched, ocean island basalt (OIB)-like source for either the basement basalts or the arc volcanic section.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Journal of Petrology, v. 47, issue 2, p. 277-299

Scholar Commons Citation

Savov, Ivan P.; Hickey-Vargas, Rosemary; D'Antonio, Massimo; Ryan, Jeffrey G.; and Spadea, Piera, "Petrology and Geochemistry of West Philippine Basin Basalts and Early Palau–Kyushu Arc Volcanic Clasts from ODP Leg 195, Site 1201D: Implications for the Early History of the Izu–Bonin–Mariana Arc" (2006). Geology Faculty Publications. 148.
https://digitalcommons.usf.edu/gly_facpub/148

Full Text URL

https://doi.org/10.1093/petrology/egi075