As reported by Shipboard Scientific Party (2001b) in the Site 1179 chapter of the Initial Reports volume, Leg 191 Site 1179 is located on abyssal seafloor northwest of Shatsky Rise, ~1650 km east of Japan. This part of the Pacific plate was formed during the Early Cretaceous, as shown by northeast-trending M-series magnetic lineations that become younger toward the northwest (Larson and Chase, 1972; Sager et al., 1988; Nakanishi et al., 1989). The site is situated on magnetic Anomaly M8 (Nakanishi et al., 1999), corresponding to an age of ~129 Ma and the Hauterivian stage of the Early Cretaceous (Gradstein et al., 1994, 1995).
The sediments recovered at Site 1179 are split into four lithostratigraphic units based on composition and color (Shipboard Scientific Party, 2001b). Unit I (0–221.52 meters below seafloor [mbsf]) is a dominantly olive-gray clay- and radiolarian-bearing diatom ooze. Unit II (221.52–246.0 mbsf) is a yellowish brown to light brown clay-rich and diatom-bearing radiolarian ooze. Unit III (246.0–283.53 mbsf) is composed of brown pelagic clay. Unit IV (283.53–377.15 mbsf) is composed of chert and some porcellanite; any softer sediments present were washed out of the core barrel by the fluid circulating during the coring process.
1Horner-Johnson, B.C., and Sager, W.W., 2004. Data report: Magnetic properties of ODP Leg 191 Site 1179 Sediments. In Sager, W.W., Kanazawa, T., and Escutia, C. (Eds.), Proc. ODP, Sci. Results, 191 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/191_SR/008/008.htm>. [Cited YYYY-MM-DD]
2Department of Earth Science, Rice University, 6100 South Main Street, Houston TX 77005-1892, USA. ben@esci.rice.edu
3Department of Oceanography, Texas A&M University, College Station TX 77843-3146, USA.
Initial receipt: 28 July 2003
Acceptance: 1 June 2004
Web publication:
27 August 2004
Ms 191SR-008