IODP expedition 351 lithostratigraphy: volcaniclastic record of Izu-Bonin-Mariana (IBM) arc initiation

Author(s): Barth, A. P.; Brandl, Philipp A.; Li, H.; Hickey-Vargas, R.; Jiang, F.; Kanayama, K.; Kusano, Y.; Marsaglia, Kathie M.; McCarthy, Anders; Meffre, S.; Savov, I. P.; Tepley, F. J., III; Yogodzinski, G. M.
Author Affiliation(s): Primary:
Indiana University, Indianapolis, IN, United States
Other:
Australian National University, Australia
Chinese Academy of Sciences, Guangzhou Institute of Geochemistry, China
Florida International University, United States
Chinese Academy of Sciences, Institute of Oceanology, China
Kanazawa University, Japan
California State University Northridge, United States
University of Lausanne, Switzerland
University of Tasmania, Australia
University of Leeds, United Kingdom
Oregon State University, United States
University of South Carolina, United States
Volume Title: AGU 2014 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2014; American Geophysical Union 2014 fall meeting, San Francisco, CA, Dec. 15-19, 2014. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The destruction of lithospheric plates by subduction is a fundamentally important process leading to arc magmatism and the creation of continental crust, yet subduction initiation and early magmatic arc evolution remain poorly understood. For many arc systems, onset of arc volcanism and early evolution are obscured by metamorphism or the record is deeply buried; however, initial products of arc systems may be preserved in forearc and backarc sedimentary records. IODP Expedition 351 recovered this history from the dispersed ash and pyroclast record in the proximal rear-arc of the northern IBM system west of the Kyushu-Palau Ridge. Drilling at Site U1438 in the Amami Sankaku Basin recovered a thick volcaniclastic record of subduction initiation and the early evolution of the Izu-Bonin Arc. A 160-m thick section of Neogene sediment overlies 1.3 kilometers of Paleogene volcaniclastic rocks with andesitic average composition; this volcaniclastic section was deposited on mafic volcanic basement rocks. The thin upper sediment layer is primarily terrigenous, biogenic and volcaniclastic mud and ooze with interspersed ash layers. The underlying Eocene to Oligocene volcaniclastic rocks are 33% tuffaceous mudstone, 61% tuffaceous sandstone, and 6% conglomerate with volcanic and rare sedimentary clasts commonly up to pebble and rarely to cobble size. The clastic section is characterized by repetitive conglomerate and sandstone-dominated intervals with intervening mudstone-dominated intervals, reflecting waxing and waning of coarse arc-derived sediment inputs through time. Volcanic lithic clasts in sandstones and conglomerates range from basalt to rhyolite in composition and include well-preserved pumice, reflecting a lithologically diverse and compositionally variable arc volcanic source.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Expedition 351; Integrated Ocean Drilling Program; Izu-Bonin Arc; Mariana Islands; Micronesia; North Pacific; Northwest Pacific; Oceania; Pacific Ocean; Volcaniclastics; West Pacific
Record ID: 2015065261
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by, and/or abstract, Copyright, American Geophysical Union, Washington, DC, United States

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