Project IBM; towards a comprehensive understanding of arc evolution and continental crust formation

Author(s): Tatsumi, Y.; Stern, R. J.
Author Affiliation(s): Primary:
Japan Agency of Marine-Earth Science and Technology, IFREE, Yokosuka, Japan
University of Texas at Dallas, United States
Volume Title: AGU 2006 fall meeting
Source: Eos, Transactions, American Geophysical Union, 87( Fall Meeting Suppl.); American Geophysical Union 2006 fall meeting, San Francisco, CA, Dec. 11-15, 2006. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0096-3941 CODEN: EOSTAJ
Note: In English
Summary: A complex drilling project proposal (ProjectIBM), including non-riser/riser IODP expeditions and petrological/geochemical/geophysical studies, is designed to achieve one major goal of the IODP Initial Science Plan, i.e., a comprehensive understanding of intra-oceanic arc evolution and continental crust formation. We focus on the Izu-Bonin-Mariana (IBM) arc-trench system, which is undoubtedly one of the best- surveyed intra-oceanic arcs and, more importantly, is characterized by the presence of 6.0-6.3 km/s Vp middle crust possibly having intermediate compositions similar to the average continental crust. We propose four linked thematic operations of IBM complex drilling to sample volcaniclastic sediments and upper and middle crustal rocks: Expedition 1 -Characterization of pre-arc crust and mantle, decoding the nature of pre-existing crust/mantle and understanding the tectonic setting of IBM arc formation by drilling at the Amami Sankaku Basin, the eastern margin of the West Philippine Basin; Expedition 2 Characterization of initial IBM magmatism, extending our understanding of the nature and tectonic setting of initial IBM arc magmatism and crust formation by deepening ODP Site 786B; Expedition 3 -Documentation of temporal variation of rear-arc magmatism, investigating volcaniclastic sediments for a temporal record of rear-arc magmatism, which may be distinct from that along the volcanic front, by drilling at the site located between two rear-arc volcanic chains; and Expedition 4 -Ultra-deep drilling to the middle crust, documenting the characteristics of the entire IBM upper and middle crust and understanding the formation process of distinctive middle crust and its role in continental crust formation and solid Earth evolution by riser-drilling at ODP Site 792. These drilling experiments, together with non-drilling elements including extensive geophysical and petrological efforts, should provide a landmark not only in IODP research, but also in the study on Earth evolution.
Year of Publication: 2006
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 18 Geophysics, Solid-Earth; Amami Sankaku Basin; Continental crust; Crust; Expeditions; Geochemistry; Geophysics; Integrated Ocean Drilling Program; Island arcs; Izu-Bonin Arc; Leg 126; Magmatism; Mantle; Mariana Trench; Middle crust; North Pacific; Northwest Pacific; ODP Site 792; Ocean Drilling Program; Pacific Ocean; Petrology; Philippine Sea; Sediments; Tectonics; Volcaniclastics; West Pacific; West Philippine Basin
Coordinates: N322355 N322359 E1402249 E1402246
Record ID: 2009091224
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