2014 Fiscal Year Final Research Report
Significance of of-axis magmatism for the accretion of oceanic crustal
| Project/Area Number |
23540530
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Geology
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| Research Institution | Niigata University |
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Principal Investigator |
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| Research Collaborator |
KANEKO Rhu 新潟大学, 自然科学研究科
KUSANO Yuki 金沢大学, 理工研究域, 博士研究員
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| Project Period (FY) |
2011-04-28 – 2015-03-31
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| Keywords | 海洋地殻 / 海嶺 / オフィオライト / オマーン / オフアクシス火成活動 |
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| Outline of Final Research Achievements |
Detailed volcanic stratigraphy in the Oman ophiolite exhibits lava accretion processes around fast-spreading ridges. The V1 sequence is divided into the lower V1 (LV1) and upper V1 (UV1) by 0.4-m thick umber layer. The lowest part of the LV1 consists of lobate sheet and pillow lava flows extruded on the flat ridge crest. Elongate pillows occurred at 230 mab (meters above the base of the extrusives) is originated from flowing down lavas and characterizes ridge frank. Accretion process at the off-axis area is recorded in the UV1 consisting of pahoehoe flows, lobate sheet flows and pillow lavas. Depleted lavas covering the 0.4-m thick umber suggest that these lavas derived from more depleted mantle source or underwent higher degree of partial melting. Because the depleted lavas are covered repeatedly by evolved lavas with similar compositions to lava in the LV1, the off-axis lava sequence should be pileup of lava flows erupted at off-axis and transported from ridge axis, repeatedly.
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| Free Research Field |
地質学，岩石学
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