Physical properties along the developing décollement in the Nankai Trough; inferences from 3-D seismic reflection data inversion and Leg 190 and 196 drilling data

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doi: 10.2973/odp.proc.sr.190196.354.2005
Author(s): Bangs, Nathan L. B.; Gulick, Sean P. S.
Ocean Drilling Program, Leg 190, Shipboard Scientific Party, College Station, TX
Author Affiliation(s): Primary:
University of Texas at Austin, Institute for Geophysics, Austin, TX, 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, 18p. 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. 23 refs.CD-ROM format, ISSN 1096-2514; WWW format, ISSN 1096-7451; illus., incl. sects.
Summary: In the Nankai Trough, the decollement megathrust initiates within the incoming sedimentary sequence along an interface within the lower Shikoku Basin facies. Scientists on Ocean Drilling Program Legs 190 and 196 penetrated the stratigraphic horizon that develops into the decollement at a reference site 12 km seaward of the deformation front, Site 1173, and in the decollement zone, at Site 1174. The core and logging-while-drilling data collected at these sites examine the lateral variation in physical properties prior to and just after initiation of decollement thrusting. We used a prestack time migrated three-dimensional (3-D) seismic reflection data volume that overlaps with the Leg 190 and 196 drill sites, along with Site 1173 and Site 1174 physical property data, to invert a seismic reflection transect (Line 215) for seismic impedance across the trench from Site 1173 to the deformation front. We used porosity estimated from seismic inversion to infer compaction and dewatering activity within the upper and lower Shikoku Basin facies as the trench wedge overburden rapidly accumulates. A compacted layer (with porosity = ∼40%) develops at the upper/lower Shikoku Basin facies boundary and the stratigraphic equivalent of the decollement zone in the trench landward of Site 1173. The compacted layer may develop because of localized dewatering, diagenetic, or cementation effects within the compacted layer or the over- and underlying layers. We speculate that the compacted layer serves as an aquitard to delay consolidation beneath the horizon that becomes the decollement zone and contributes to the decollement development.
Year of Publication: 2005
Research Program: ODP Ocean Drilling Program
Key Words: 16 Structural Geology; 20 Geophysics, Applied; Decollement; Faults; Geophysical methods; Leg 190; Leg 196; Lithofacies; Lithostratigraphy; Nankai Trough; North Pacific; Northwest Pacific; ODP Site 1173; ODP Site 1174; Ocean Drilling Program; Ocean floors; Pacific Ocean; Physical properties; Reflection methods; Seismic methods; Subduction zones; Tectonics; Three-dimensional models; West Pacific
Coordinates: N322000 N322100 E1345800 E1345700
N321500 N321500 E1350200 E1350200
Record ID: 2005060948
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