Osmium behavior in a subduction system elucidated from chromian spinel in Bonin Island beach sands

Abstract

Research Article| November 01, 2011 Osmium behavior in a subduction system elucidated from chromian spinel in Bonin Island beach sands Katsuhiko Suzuki; Katsuhiko Suzuki * 1Institute for Research on Earth Evolution (IFREE), Japan Agency for Marine Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka 237-0061, Japan2Precambrian Ecosystem Laboratory, Japan Agency for Marine Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka 237-0061, Japan *E-mail: katz@jamstec.go.jp. Search for other works by this author on: GSW Google Scholar Ryoko Senda; Ryoko Senda 1Institute for Research on Earth Evolution (IFREE), Japan Agency for Marine Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka 237-0061, Japan Search for other works by this author on: GSW Google Scholar Kenji Shimizu Kenji Shimizu 1Institute for Research on Earth Evolution (IFREE), Japan Agency for Marine Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka 237-0061, Japan2Precambrian Ecosystem Laboratory, Japan Agency for Marine Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka 237-0061, Japan Search for other works by this author on: GSW Google Scholar Geology (2011) 39 (11): 999–1002. https://doi.org/10.1130/G32044.1 Article history received: 05 Jan 2011 rev-recd: 17 May 2011 accepted: 24 May 2011 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Katsuhiko Suzuki, Ryoko Senda, Kenji Shimizu; Osmium behavior in a subduction system elucidated from chromian spinel in Bonin Island beach sands. Geology 2011;; 39 (11): 999–1002. doi: https://doi.org/10.1130/G32044.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The Os isotopic system is a potential tracer of a recycled crustal component in mantle or volcanic rocks because of the significant contrast between Os isotope ratios of crust and mantle. However, the potential for crustal contamination overprinting this possible signal has hampered the utility of Os isotopic ratios. We explored the use of Os isotopes in chromian spinel (Cr-spinel) as a discriminator of primitive magma Os compositions in the Izu-Bonin arc, using beach sands as composite samples of the boninite and tholeiite magmas in three different islands. Cr-spinel is an early-stage crystal that preserves its isotopic composition even during later crustal contamination of the bulk rock. We found highly unradiogenic Os isotopic compositions in Cr-spinels from boninites, suggesting that they represent primitive magmas with slight or no Os contribution from the subducting slab during the generation of boninites in the infant arc stage (48–46 Ma). Conversely, the radiogenic Os isotopic ratios in Cr-spinels from tholeiites most likely reflect the contribution from a slab-derived component, because more oxidative conditions in the subarc mantle probably allowed Os to mobilize from the subducting slab during the transitional arc stage (45–41 Ma). Although shallow-level assimilation of crustal components with radiogenic Os may overprint the original Os signature of tholeiite magma during its ascent, Cr-spinel allows us to compensate such possibilities. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.