Faculty Publications

Document Type

Article

Abstract

At Ocean Drilling Program (ODP) Site 1090 (lat 42854.89S, long 8854.09E) locatedin a water depth of 3702 m on the Agulhas Ridge in the sub-Antarctic South Atlantic, ~300 m of middle Eocene to middle Miocenesediments were recovered with the advancedpiston corer (APC) and the extendedcore barrel (XCB). U-channel samplesfrom the 70–230 meters composite depth(mcd) interval provide a magnetic polaritystratigraphy that is extended to 380 mcd byshipboard whole-core and discrete sampledata. The magnetostratigraphy can be interpretedby the fit of the polarity-zone patternto the geomagnetic polarity time scale(GPTS) augmented by isotope data andbioevents with documented correlation tothe GPTS. Three normal-polarity subchrons(C5Dr.1n, C7Ar.1n, and C13r.1n),not included in the standard GPTS, are recordedat Site 1090. The base of the sampledsection is correlated to C19n (middleEocene), although the interpretation is unclearbeyond C17r. The top of the sampledsection is correlated to C5Cn (late earlyMiocene), although, in the uppermost 10 m of the sampled section, a foraminifer (Globorotaliasphericomiozea) usually associatedwith the Messinian and early Pliocene hasbeen identified. 87Sr/86Sr, d13C, and d18Ovalues measured on foraminifera, includingthe d18O and d13C shifts close to the Eocene/Oligocene boundary, support the correlationto the GPTS. For the interval spanningthe Oligocene/Miocene boundary, benthicd13C, d18O, and 87Sr/86Sr records from Site1090 can be correlated to isotope recordsfrom ODP Site 929 (Ceara Rise), providing support for the recently-published Oligocene/Miocene boundary age (22.92 Ma) of Shackleton et al.

Rights

Channell, J. E. T., Galeotti, S., Martin, E. E., Billups, K., Scher, H. D., & Stoner, J. S. (2003). Eocene to Miocene magnetostratigraphy, biostratigraphy, and chemostratigraphy at ODP Site 1090 (sub-Antarctic South Atlantic). Geological Society of America Bulletin 115 (5), 607-623.

© Geological Society of America Bulletin 2003, Geological Society of America

Copyright not claimed on content prepared wholly by U.S. government employees within scope of their employment. Individual scientists are hereby granted permission, without fees or further requests to GSA, to use a single figure, a single table, and/or a brief paragraph of text in subsequent works and to make unlimited copies of items in GSA's journals for noncommercial use in classrooms to further education and science. This file may not be posted to any Web site, but authors may post the abstracts only of their articles on their own or their organization's Web site providing the posting includes a reference to the article's full citation. GSA provides this and other forums for the presentation of diverse opinions and positions by scientists worldwide, regardless of their race, citizenship, gender, religion, or political viewpoint. Opinions presented in this publication do not reflect official opinions of the Society.

Share

COinS