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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
2007
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| Online Access: | https://doi.org/10.1594/PANGAEA.668386 |
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| _version_ | 1867170453405040640 |
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| author | Haraguchi, Satoru Ishii, Teruaki |
| author_facet | Haraguchi, Satoru Ishii, Teruaki |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Early arc volcanism during Eocene to Oligocene in the Izu forearc region was investigated during ODP Legs 125 and 126 in 1989, and effusive and intrusive volcanics were recovered from Leg 125 Site 786. These rocks were all classified into boninites and associated rocks by Leg 125 Shipboard Scientific Party, and they concluded that boninitic volcanism had occurred before 40 Ma, and arc tholeiitic volcanism began after 40 Ma. In this study, lava flows and breccias that classified into boninite series are divided into two groups, tholeiite and boninite, based on petrographical and petrological properties. Both series are also distinguished by bulk rock composition. It is considered that the sources of both rock types have similar depleted compositions because of their similar, very low bulk HFSE concentrations. We suggest that boninitic and tholeiitic volcanism occurred closely in time and space, and reflected different temperature and water condition. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_668386 |
| institution | PANGAEA |
| language | en |
| publishDate | 2007 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Major element composition of phenocrysts from the volcanic basement of ODP Hole 125-786B, Izu forearc region, Philippine Sea Haraguchi, Satoru Ishii, Teruaki 125-786B; DRILL; Drilling/drill rig; Joides Resolution; Leg125; North Pacific Ocean; Ocean Drilling Program; ODP Early arc volcanism during Eocene to Oligocene in the Izu forearc region was investigated during ODP Legs 125 and 126 in 1989, and effusive and intrusive volcanics were recovered from Leg 125 Site 786. These rocks were all classified into boninites and associated rocks by Leg 125 Shipboard Scientific Party, and they concluded that boninitic volcanism had occurred before 40 Ma, and arc tholeiitic volcanism began after 40 Ma. In this study, lava flows and breccias that classified into boninite series are divided into two groups, tholeiite and boninite, based on petrographical and petrological properties. Both series are also distinguished by bulk rock composition. It is considered that the sources of both rock types have similar depleted compositions because of their similar, very low bulk HFSE concentrations. We suggest that boninitic and tholeiitic volcanism occurred closely in time and space, and reflected different temperature and water condition. |
| title | Major element composition of phenocrysts from the volcanic basement of ODP Hole 125-786B, Izu forearc region, Philippine Sea |
| topic | 125-786B; DRILL; Drilling/drill rig; Joides Resolution; Leg125; North Pacific Ocean; Ocean Drilling Program; ODP |
| url | https://doi.org/10.1594/PANGAEA.668386 |