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Magnetic-, isotopic-, and biostratigraphies in ODP Hole 177-1090

Authors
Publisher
PANGAEA
Publication Date
Identifiers
DOI: 10.1594/pangaea.717737
Keywords
  • 177-1090
  • 87Sr/86Sr
  • Age
  • Difference
  • Age
  • Maximum/Old
  • Age
  • Minimum/Young
  • Age Diff
  • Age Max
  • Age Min
  • Age Model
  • Age Model
  • Gpts (Geomagnetic Polarity Timescale)
  • Cande And Kent (1995)
  • Age Model
  • Optional
  • Age Model (Shackleton Et Al
  • 2000)
  • Age Model Opt
  • Ageprof Dat Des
  • Ageprofile Datum Description
  • Cande And Kent (1992)
  • Chronozone
  • Comment
  • Composite Core
  • Depth
  • Composite Bottom
  • Depth
  • Composite Top
  • Depth C Bot
  • Depth C Top
  • Fo = First Occurrence
  • Lo = Last Occurrence
  • Lco = Last Common Occurrence
  • Joides Resolution
  • Leg177
  • Mass Spectrometer Micromass Sector 54
  • Ocean Drilling Program
  • Odp
  • Polarity Chron
  • Rescaled To The Age (22
  • 92 Ma) For The Oligocene/Miocene Boundary
  • South Atlantic Ocean
  • Strontium 87/Strontium 86
Disciplines
  • Archaeology
  • Earth Science

Abstract

At Ocean Drilling Program (ODP) Site 1090 (lat 42°54.8'S, long 8°54.0'E) located in a water depth of 3702 m on the Agulhas Ridge in the sub-Antarctic South Atlantic, ~300 m of middle Eocene to middle Miocene sediments were recovered with the advanced piston corer (APC) and the extended core barrel (XCB). U-channel samples from the 70-230 meters composite depth (mcd) interval provide a magnetic polarity stratigraphy that is extended to 380 mcd by shipboard whole-core and discrete sample data. The magnetostratigraphy can be interpreted by the fit of the polarity-zone pattern to the geomagnetic polarity time scale (GPTS) augmented by isotope data and bioevents with documented correlation to the GPTS. Three normal-polarity subchrons (C5Dr.1n, C7Ar.1n, and C13r.1n), not included in the standard GPTS, are recorded at Site 1090. The base of the sampled section is correlated to C19n (middle Eocene), although the interpretation is unclear beyond C17r. The top of the sampled section is correlated to C5Cn (late early Miocene), although, in the uppermost 10 m of the sampled section, a foraminifer (Globorotalia sphericomiozea) usually associated with the Messinian and early Pliocene has been identified. 87Sr/86Sr, d13C, and d18O values measured on foraminifera, including the d18O and d13C shifts close to the Eocene/Oligocene boundary, support the correlation to the GPTS. For the interval spanning the Oligocene/Miocene boundary, benthic d13C, d18O, and 87Sr/86Sr records from Site 1090 can be correlated to isotope records from ODP Site 929 (Ceara Rise), providing support for the recently-published Oligocene/Miocene boundary age (22.92 Ma) of Shackleton et al.

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