Microstructural variation in sediments from the toe of the Nankai accretionary prism; results of scanning electron microscope analysis

Online Access: Get full text
doi: 10.2973/odp.proc.sr.190196.212.2004
Author(s): Sunderland, E. Blanche; Morgan, Julia K.
Ocean Drilling Program, Leg 190, Shipboard Scientific Party, College Station, TX
Author Affiliation(s): Primary:
Rice University, Department of Geology and Geophysics, Houston, 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, 27p. 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. 38 refs.CD-ROM format, ISSN 1096-2514; WWW format, ISSN 1096-7451; illus.
Summary: Scanning electron microscope analyses of sediment samples collected from the frontal portion of the Nankai accretionary prism and Shikoku Basin during Ocean Drilling Program Leg 190 show systematic changes in clay microstructure and microfabric that correlate with depth, lithology, sediment deformation, and changing physical properties. Heterogeneous, open sediment textures found in the shallower lithologies, such as the upper Shikoku Basin facies, are characterized by random distributions of coarse particle aggregates and fine-grained clay minerals distributed throughout the matrix. The degree of clay mineral preferred orientation (CPO) generally increases with depth and adjacent to deformation structures but is retarded in an anomalous zone of high porosities at the reference Site 1173. Clay microstructures in and below the anomalous zone are very similar and provide little evidence that clays serve as the cementing agent. Deeper sediments, including most of the lower Shikoku Basin facies, exhibit more homogeneous distributions of dispersed and uniformly sized clay particles and commonly exhibit a high degree of CPO. The transition in texture appears to occur at the protodecollement horizon at the reference Site 1173 and slightly shallower in the section within the protothrust zone. The coincidence of this transition with noticeable downhole decreases in smectite abundance and compressional wave velocity (Vp) at Site 1173 highlight an important diagenetic boundary that may help to localize slip along the accretionary decollement as it propagates seaward.
Year of Publication: 2005
Research Program: ODP Ocean Drilling Program
Key Words: 06 Petrology, Sedimentary; Accretionary wedges; Clay mineralogy; Clay minerals; Deformation; Fabric; Leg 190; Marine sediments; Microstructure; Nankai Trough; North Pacific; Northwest Pacific; Ocean Drilling Program; Pacific Ocean; SEM data; Sediments; Sheet silicates; Shikoku Basin; Silicates; Textures; Variations; West Pacific
Coordinates: N313000 N324500 E1351500 E1340000
Record ID: 2005060943
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.