Provenance of Miocene submarine fans in the Shikoku Basin; results from NanTroSEIZE and implications for stratigraphic correlation of subduction inputs

Author(s): Pickering, K. T.; Underwood, M.; Moore, G. F.
Author Affiliation(s): Primary:
University College London (UCL), Department of Earth Sciences, London, United Kingdom
University of Missouri, Department of Earth Sciences, United States
University of Hawaii, Geology & Geophysics, United States
Volume Title: AGU 2013 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2013; American Geophysical Union 2013 fall meeting, San Francisco, CA, Dec. 9-13, 2013. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English. 2 refs.
Summary: Seismo-stratigraphy, coring and LWD during IODP Expeditions 319, 322, and 333 (Sites C0011 / C0012) show three Miocene submarine fans in the NE Shikoku Basin, with broadly coeval deposits at ODP Site 1177 and DSDP Site 297, NW Shikoku Basin. Pickering et al. (2013) have shown that the sediment dispersal patterns for these fans have major implications for paleogeographies at that time. The oldest, Middle Miocene Kyushu Fan is the finest grained, has a sheet-like geometry, and was fed by quartz-rich sediment gravity-flows derived mostly from an ancestral landmass in the East China Sea. This likely sediment provenance is further supported by U-Pb zircon and fission track analysis of both zircons and apatites from sediments taken from the forearc and trench of the Nankai Trough, together with rivers from southwest Japan, that point to the influence of the Yangtze River in supplying into the Shikoku Basin prior to rifting of the Okinawa Trough at 10 to 6 Ma (Clift et al. 2013). During prolonged hemipelagic mud deposition at C0011-C0012 (12.2 to 9.1 Ma), sand supply continued at Sites 1177 and 297. Sand delivery to much of the Shikoku Basin, however, probably halted during a phase of sinistral strike-slip and oblique plate motion, after which the Daiichi Zenisu Fan (9.1 to 8.0 Ma) was fed by submarine channels. The youngest fan (Daini Zenisu; 8.0 to 7.6 Ma) has sheet-like geometry with thick-bedded, coarse-grained pumiceous sandstones. The pumice fragments were fed from a mixed provenance that included the collision zone of the Izu-Bonin and Honshu arcs. The shift from channelized to sheet-like flows was probably favored by renewal of relatively rapid northward subduction, which accentuated the trench as a bathymetric depression. Understanding the stratigraphic position and 3-D geometry of the sandbodies has important implications for stratigraphic correlation throughout the northern Shikoku Basin, together with subduction-related processes, including the potential for focused fluid flow and fluid overpressures above and below the plate-boundary fault. References Pickering, K. T., Underwood, M. B., Saito, S., Naruse, H., Kutterolf, S., Scudder, R., Park, J.-O., Moore, G. F. & Slagle, A. 2013. Geochemistry, Geophysics, Geosystems, 14, doi:10.1002/ggge.20107 Clift, P. D., Carter, A., Nicholson, U. & Masago, H. 2013. Tectonics, doi: 10.1002/tect.20033
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Cenozoic; IODP Site C0011; IODP Site C0012; Integrated Ocean Drilling Program; Miocene; NanTroSEIZE; Neogene; North Pacific; Northwest Pacific; Pacific Ocean; Plate tectonics; Shikoku Basin; Subduction; Tertiary; West Pacific
Coordinates: N324944 N324945 E1365256 E1365254
Record ID: 2015037323
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