Ocean Drilling Program (ODP) Sites 1257–1261 recovered thick sections of Upper Cretaceous–Eocene oceanic sediments on Demerara Rise off the east coast of Surinam and French Guiana, South America. Paleomagnetic and rock magnetic measurements of ~800 minicores established a high-resolution composite magnetostratigraphy spanning most of the Maastrichtian–Eocene. Magnetic behavior during demagnetization varied among lithologies, but thermal demagnetization steps >200°C were generally successful in removing present-day normal polarity overprints and a downward overprint induced during the ODP coring process. Characteristic remanent magnetizations and associated polarity interpretations were generally assigned to directions observed at 200°–400°C, and the associated polarity interpretations were partially based on whether the characteristic direction was aligned or apparently opposite to the low-temperature "north-directed" overprint. Biostratigraphy and polarity patterns constrained assignment of polarity chrons. The composite sections have a complete polarity record of Chrons C18n (middle Eocene)–C34n (Late Cretaceous).
1Suganuma, Y., and Ogg, J.G., 2006. Campanian through Eocene magnetostratigraphy of Sites 1257–1261, ODP Leg 207, Demerara Rise (western equatorial Atlantic). In Mosher, D.C., Erbacher, J., and Malone, M.J. (Eds.), Proc. ODP, Sci. Results, 207 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/207_SR/102/102.htm>. [Cited YYYY-MM-DD]
2Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo,Bunkyo-ku, Tokyo 113-0033, Japan. suganuma@eps.s.u-tokyo.ac.jp
3Department of Earth and Atmospheric Sciences, Civil Engineering Building, Purdue University, 550 Stadium Mall Drive, West Lafayette IN 47907-2051, USA.
Initial receipt: 26 May 2004
Acceptance: 23 May 2005
Web
publication: 14 March 2006
Ms 207SR-102