Composition and sources of clay from the trench slope and shallow accretionary prism of Nankai Trough

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doi: 10.2973/odp.proc.sr.190196.206.2003
Author(s): Underwood, Michael B.; Steurer, Joan F.
Ocean Drilling Program, Leg 190, Shipboard Scientific Party, College Station, TX
Author Affiliation(s): Primary:
University of Missouri Columbia, Department of Geological Sciences, Columbia, MO, United States
Other:
University of Tokyo, Japan
Volume Title: Proceedings of the Ocean Drilling Program; scientific results; deformation and fluid flow processes in the Nankai Trough accretionary prism; coring, logging while drilling and advanced CORKs covering Legs 190 to 196 of the cruises of the drilling vessel JOIDES Resolution; Sydney, Australia, to Yokohama, Japan, Sites 1173-1178, 23 May-16 July 2000; and Keelung, Taiwan, to Kochi, Japan, Sites 808-1173, 2 May-1 July 2001
Volume Author(s): Moore, Gregory F.; Taira, Asahiko; Klaus, Adam; Becker, Keir; Becker, Luann; Boeckel, Babette; Cragg, Barry A.; Dean, P. Allison; Fergusson, Christopher L.; Henry, Pierre; Hirano, Satoshi; Hisamitsu, Toshio; Hunze, Sabine; Kastner, Miriam; Maltman, Alex J.; Morgan, Julia K.; Murakami, Yuki; Saffer, Demian M.; Sánchez-Gómez, Mario; Screaton, Elizabeth J.; Smith, David C.; Spivack, Arthur J.; Steurer, Joan F.; Tobin, Harold J.; Ujiie, Kohtaro; Underwood, Michael B.; Wilson, Moyra E. J.; Mikada, Hitoshi; Moore, J. Casey; Austin, Gary L.; Bangs, Nathan L. B.; Bourlange, Sylvain; Broilliard, Julien; Brückmann, Warner; Corn, Ernest Ray; Davis, Earl E.; Flemings, Peter B.; Goldberg, David S.; Gulick, Sean P. S.; Hansen, Martin Bak; Hayward, Nathan; Hills, Denise J.; Ienaga, Masanori; Ishiguro, Hiroyasu; Kinoshita, Masataka; Macdonald, Robert D.; McNeill, Lisa; Obana, Shinichi; Hong, Ong Swee; Peacock, Sheila; Pettigrew, Thomas L.; Saito, Saneatsu; Sawa, Takao; Thaiprasert, Nophawit; Tsurumi, Hikaru
Source: Proceedings of the Ocean Drilling Program; scientific results; deformation and fluid flow processes in the Nankai Trough accretionary prism; coring, logging while drilling and advanced CORKs covering Legs 190 to 196 of the cruises of the drilling vessel JOIDES Resolution; Sydney, Australia, to Yokohama, Japan, Sites 1173-1178, 23 May-16 July 2000; and Keelung, Taiwan, to Kochi, Japan, Sites 808-1173, 2 May-1 July 2001, Gregory F. Moore, Asahiko Taira, Adam Klaus, Keir Becker, Luann Becker, Babette Boeckel, Barry A. Cragg, P. Allison Dean, Christopher L. Fergusson, Pierre Henry, Satoshi Hirano, Toshio Hisamitsu, Sabine Hunze, Miriam Kastner, Alex J. Maltman, Julia K. Morgan, Yuki Murakami, Demian M. Saffer, Mario Sánchez-Gómez, Elizabeth J. Screaton, David C. Smith, Arthur J. Spivack, Joan F. Steurer, Harold J. Tobin, Kohtaro Ujiie, Michael B. Underwood, Moyra E. J. Wilson, Hitoshi Mikada, J. Casey Moore, Gary L. Austin, Nathan L. B. Bangs, Sylvain Bourlange, Julien Broilliard, Warner Brückmann, Ernest Ray Corn, Earl E. Davis, Peter B. Flemings, David S. Goldberg, Sean P. S. Gulick, Martin Bak Hansen, Nathan Hayward, Denise J. Hills, Masanori Ienaga, Hiroyasu Ishiguro, Masataka Kinoshita, Robert D. Macdonald, Lisa McNeill, Shinichi Obana, Ong Swee Hong, Sheila Peacock, Thomas L. Pettigrew, Saneatsu Saito, Takao Sawa, Nophawit Thaiprasert and Hikaru Tsurumi; Ocean Drilling Program, Leg 190, Shipboard Scientific Party, College Station, TX; Ocean Drilling Program, Leg 196, Shipboard Scientific Party, College Station, TX. Proceedings of the Ocean Drilling Program, Scientific Results (CD ROM), Vol.190/196, 28p. Publisher: Texas A&M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 1096-2514
Note: In English. Available only on CD-ROM in PDF format and on the Web in PDF or HTML. 90 refs.CD-ROM format, ISSN 1096-2514; WWW format, ISSN 1096-7451; illus., incl. strat. cols., 1 table, geol. sketch maps
Summary: Three sites were cored on the landward slope of the Nankai margin of southwest Japan during Leg 190 of the Ocean Drilling Program. Sites 1175 and 1176 are located in a trench-slope basin that was constructed during the early Pleistocene (∼1 Ma) by frontal offscraping of coarse-grained trench-wedge deposits. Rapid uplift elevated the substrate above the calcite compensation depth and rerouted a transverse canyon-channel system that had delivered most of the trench sediment during the late Pliocene (1.06-1.95 Ma). The basin's depth is now ∼3000 to 3020 m below sea level. Clay-sized detritus (<2 µm) did not change significantly in composition during the transition from trench-floor to slope-basin environment. Relative mineral abundances for the two slope-basin sites average 36-37 wt% illite, 25 wt% smectite, 22-24 wt% chlorite, and 15-16 wt% quartz. Site 1178 is located higher up the landward slope at a water depth of 1741 m, ∼70 km from the present-day deformation front. There is a pronounced discontinuity ∼200 m below seafloor between muddy slope-apron deposits (Quaternary-late Miocene) and sandier trench-wedge deposits (late Miocene; 6.8-9.63 Ma). Clay minerals change downsection from an illite-chlorite assemblage (similar to Sites 1175 and 1176) to one that contains substantial amounts of smectite (average = 45 wt% of the clay-sized fraction; maximum = 76 wt%). Mixing in the water column homogenizes fine-grained suspended sediment eroded from the Izu-Bonin volcanic arc, the Izu-Honshu collision zone, and the Outer Zone of Kyushu and Shikoku, but the spatial balance among those contributors has shifted through time. Closure of the Central America Seaway at ∼3 Ma was particularly important because it triggered intensification of the Kuroshio Current. With stronger and deeper flow of surface water toward the northeast, the flux of smectite from the Izu-Bonin volcanic arc was dampened and more detrital illite and chlorite were transported into the Shikoku-Nankai system from the Outer Zone of Japan.
Year of Publication: 2005
Research Program: ODP Ocean Drilling Program
Key Words: 06 Petrology, Sedimentary; Accretionary wedges; Algae; Biostratigraphy; Cenozoic; Clastic rocks; Clastic sediments; Clay; Clay mineralogy; Clay minerals; Leg 190; Lithofacies; Lithostratigraphy; Marine sediments; Microfossils; Miocene; Mudstone; Nankai Trough; Nannofossils; Neogene; North Pacific; Northwest Pacific; ODP Site 1175; ODP Site 1176; Ocean Drilling Program; Ocean floors; Pacific Ocean; Plantae; Quaternary; Sedimentary rocks; Sediments; Sheet silicates; Silicates; Tertiary; Trenches; West Pacific; X-ray diffraction data
Coordinates: N313000 N324500 E1351500 E1340000
Record ID: 2005060940
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.

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