Sites 1251 (44°34.213´N, 125°4.440´W; 1211 m water depth) and 1252 (44°35.167´N, 125°5.569´W; 1039 m water depth) were drilled on the eastern flank of the southern summit of Hydrate Ridge off Oregon in the northeast Pacific Ocean, where well-stratified sediments were deposited at a rapid rate. Unconformities and debris flow layers of middle Pleistocene age were found at both sites. Their ages are of great importance in constructing the geohistory of Hydrate Ridge. Detailed diatom biostratigraphy of the middle to late Pleistocene of Sites 1251 and 1252 was carried out for this purpose.
1Watanabe, M., 2006. Data report: Diatom biostratigraphy of Sites 1251 and 1252. In Tréhu, A.M., Bohrmann, G., Torres, M.E., and Colwell, F.S. (Eds.), Proc. ODP, Sci. Results, 204: College Station, TX (Ocean Drilling Program), 1–10. doi:10.2973/odp.proc.sr.204.123.2006
2Geological Survey of Japan, AIST, 1-1-1 Higashi, Tsukuba 305-8567, Japan. mht.watanabe@aist.go.jp
Initial receipt: 4 May 2005
Acceptance: 1 December 2005
Web publication: 26 April 2006
Ms 204SR-123