Ujiie, Kohtaro; Hisamitsu, Toshio; Maltman, Alex J.; Morgan, Julia K.; Sanchez-Gomez, Mario; Tobin, Harold J. (2005): Deformation structures and magnetic fabrics at Site 1178; implication for deformation history recorded in accreted sediments at an evolved portion of the Nankai accretionary prism. Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: 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., Sanchez-Gomez, 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, Brueckmann, 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, 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, 190/196, georefid:2005-060945

Abstract:
During Leg 190, accreted sediments at an evolved portion of the Nankai accretionary prism were penetrated. Deformation structures and anisotropy of magnetic susceptibility (AMS) data from Site 1178 indicate that structural and magnetic fabrics formed at the frontal part of the prism have been preserved, even approximately 65 km landward of the deformation front. As the sediments approached the deformation front, the bedding/fissility-parallel magnetic fabric took on a northeast-southwest-trending subhorizontal maximum AMS axis because of northwest-directed bedding-parallel compression. Subsequent faulting, represented by brecciated zones, took place at the frontal part of the accretionary prism, which is presumably equivalent to the imbricate thrusts in the prism. During this process, a steeply dipping bedding-oblique foliation developed in a fault zone, >100 m in thickness. The foliation was formed as a flattening plane associated with shearing deformation and alternates with brecciated zones, giving a geometric relationship similar to S-C or P-Y fabric. The magnetic fabric oriented parallel to the bedding-oblique foliation records pervasive strain related to faulting. Bedding and bedding-parallel magnetic fabric together with fissility were rotated about a horizontal axis during frontal accretion, resulting in a seaward-verging magnetic fabric with northeast-southwest-trending subhorizontal maximum AMS axes. Overprinting of the deformation and/or modification of preexisting fabrics during subsequent rapid seaward growth of the Nankai accretionary prism has not been recorded in the accreted sediments at Site 1178, suggesting that later penetrative deformation was not significant at shallow burial depths in the prism.
Coverage:
West: 134.2800 East: 134.2900 North: 32.4400 South: 32.4300
Relations:
Expedition: 190
Site: 190-1178
Supplemental Information:
Available only on CD-ROM in PDF format and on the Web in PDF or HTML
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.190196.202.2003 (c.f. for more detailed metadata)
Data download: application/pdf
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