Boninitic volcanism in the Oman ophiolite: Implications for thermal condition during transition from spreading ridge to arc

Abstract

Research Article| October 01, 2002 Boninitic volcanism in the Oman ophiolite: Implications for thermal condition during transition from spreading ridge to arc Tsuyoshi Ishikawa; Tsuyoshi Ishikawa 1Institute of Geosciences, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan Search for other works by this author on: GSW Google Scholar Kazuya Nagaishi; Kazuya Nagaishi 1Institute of Geosciences, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan Search for other works by this author on: GSW Google Scholar Susumu Umino Susumu Umino 1Institute of Geosciences, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan Search for other works by this author on: GSW Google Scholar Geology (2002) 30 (10): 899–902. https://doi.org/10.1130/0091-7613(2002)030<0899:BVITOO>2.0.CO;2 Article history received: 23 Jan 2002 rev-recd: 15 Jun 2002 accepted: 20 Jun 2002 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Tsuyoshi Ishikawa, Kazuya Nagaishi, Susumu Umino; Boninitic volcanism in the Oman ophiolite: Implications for thermal condition during transition from spreading ridge to arc. Geology 2002;; 30 (10): 899–902. doi: https://doi.org/10.1130/0091-7613(2002)030<0899:BVITOO>2.0.CO;2 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 discovery of boninite, a typical high-MgO andesite, in the Oman ophiolite is reported. The boninites in the Oman ophiolite occur as lavas and dikes of the Alley volcanic sequence that overlie or crosscut the spreading-ridge–derived lavas (Geotimes volcanic sequence) and sheeted dikes. The phenocryst mineral assemblage and the major and trace element compositions observed for these boninites resemble those of the Izu-Mariana forearc boninites, indicating that the Alley boninites represent primitive melt generated by partial melting of hydrous peridotite. The occurrence of boninite provides strong thermal and chemical constraints on the formation of the Oman ophiolite that require hot, hydrous shallow mantle (>1250 °C at <30 km depth) to have underlain the proto–Oman ophiolite at the time of boninite generation. The initiation of subduction of the young, hot oceanic lithosphere (and obduction of the future Oman ophiolite) near the spreading ridge and the resultant melting of the highly depleted, shallow-mantle wedge metasomatized by slab-derived fluid represent the most favorable mechanism for the genesis of the Alley boninites. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.