From October to December in 1996, Sites 1039 through 1043 were drilled on the lower continental slope and the bottom of the Middle American Trench. Planktonic foraminifers were obtained from 377 samples of the total 487 examined. The Pliocene- to Pleistocene-age sediments of Sites 1039 and 1043 are continuous from Zones N19 through N23. At Sites 1039 and 1040, middle Miocene sediments are also continuous, encompassing Zones N8 through N12. The sequences of the upper part of Sites 1040, 1041, 1042, and 1043 are décollements, tentatively assignable to Zone N19 for Sites 1040, 1041, and 1042 and to Zone N22 for Site 1043. The oldest sediments of these sites are assigned to Zone N7 (latest early Miocene), ~17 Ma in age.
1Ibaraki, M., 2000. Planktonic foraminifers off Costa Rica in the East Pacific Ocean—biostratigraphic and chronostratigraphic analyses. In Silver, E.A., Kimura, G., and Shipley, T.H. (Eds.), Proc. ODP, Sci. Results, 170 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/170_SR/chap_01/chap_01.htm>. [Cited YYYY-MM-DD]
2Geoscience Institute, Faculty of Science, Shizuoka University, Shizuoka, 422-8529, Japan. Correspondence author: sbmibar@ipc.shizuoka.ac.jp
Initial receipt: 15 April 1999
Acceptance: 27 September 1999
Web publication: 30 June 2000
Ms 170SR-001