The University of Southampton
University of Southampton Institutional Repository

Integrated chronostratigraphic calibration of the Oligocene-Miocene boundary at 24.0 ± 0.1 Ma from the CRP-2A drill core, Ross Sea, Antarctica

Integrated chronostratigraphic calibration of the Oligocene-Miocene boundary at 24.0 ± 0.1 Ma from the CRP-2A drill core, Ross Sea, Antarctica
Integrated chronostratigraphic calibration of the Oligocene-Miocene boundary at 24.0 ± 0.1 Ma from the CRP-2A drill core, Ross Sea, Antarctica
An expanded Oligocene-Miocene boundary interval recovered in the Cape Roberts Project CRP-2A core from beneath the Ross Sea, Antarctica, has yielded a high-resolution integrated chrono stratigraphy that has, in turn, enabled a new, more direct, calibration of magnetic polarity and biostratigraphic events. The Oligocene-Miocene boundary interval in the CRP-2A core comprises three 60-m-thick, rapidly deposited (>0.5 m/k.y.) sedimentary sequences (sequences 9, 10, and 11). In sequences 10 and 11, single-crystal, laser-fusion 40Ar/39Ar analyses of anorthoclase phenocrysts from two tephra horizons independently calibrate the CRP-2A magnetic-polarity stratigraphy and age model. Sequences 10 and 11 encompass subchron C6Cn.3n, which is dated as 24.3 ± 0.1 to 24.16 ± 0.1 Ma. Sequence 9 is interpreted to encompass subchron C6Cn.2n and the Oligocene-Miocene boundary, which is dated as 24.0 ± 0.1 Ma. These ages are 0.2 m.y. older than those of the geomagnetic polarity time scale calibrated from seafloor-spreading ridges and 0.9–1.3 m.y. older than the newly proposed astronomically calibrated ages. We contend that the discrepancy with the astronomically calibrated ages arises from a mismatch of three 406 k.y. eccentricity cycles or a 1.2 m.y. modulation of obliquity amplitude in the astronomical calibration of the Oligocene–Miocene time scale.
chronostratigraphy, isotope dating, Antarctica, biostratigraphy, Cape Roberts Project
0091-7613
1043-1046
Wilson, G.S.
2d9030eb-9036-46a9-b1c5-a4254a0cf861
Roberts, A.P.
bfc571f6-9c7a-4cc5-8df9-2c41ef5ac2a1
Harwood, D.M.
34ecd7a8-276b-4c93-b974-ba35bb91fcf8
Fielding, C.R.
00ff3f53-655d-4717-8bcf-2a09cd8ef341
Watkins, D.K.
1a4d6b14-5712-4969-b295-d995cdd5f31a
Naish, T.R.
6bfa47d3-23c9-47f3-9504-7d444ceb8798
Florindo, F.
8782f358-6dd8-4531-aaf1-4e1e859d52db
Sagnotti, L.
c9bacb8c-1e84-4719-9f62-0989ec640f3b
Scherer, R.P.
579d44b4-6618-4000-a230-0d5b3c439635
Villa, G.
85aa5759-a512-4e15-808e-ac20b94d3e14
Lavelle, M.
326fce07-e718-410e-972b-207645d69f8f
McIntosh, W.C.
c5c06698-67c1-4eae-86f0-d10cacaa0e95
Bohaty, S.M.
7d4cdf98-d06a-4d84-b2c6-d2cbb8592f91
Verosub, K.L.
71b9c710-71e8-4579-b6c8-5f19c5b1f8f3
Wilson, G.S.
2d9030eb-9036-46a9-b1c5-a4254a0cf861
Roberts, A.P.
bfc571f6-9c7a-4cc5-8df9-2c41ef5ac2a1
Harwood, D.M.
34ecd7a8-276b-4c93-b974-ba35bb91fcf8
Fielding, C.R.
00ff3f53-655d-4717-8bcf-2a09cd8ef341
Watkins, D.K.
1a4d6b14-5712-4969-b295-d995cdd5f31a
Naish, T.R.
6bfa47d3-23c9-47f3-9504-7d444ceb8798
Florindo, F.
8782f358-6dd8-4531-aaf1-4e1e859d52db
Sagnotti, L.
c9bacb8c-1e84-4719-9f62-0989ec640f3b
Scherer, R.P.
579d44b4-6618-4000-a230-0d5b3c439635
Villa, G.
85aa5759-a512-4e15-808e-ac20b94d3e14
Lavelle, M.
326fce07-e718-410e-972b-207645d69f8f
McIntosh, W.C.
c5c06698-67c1-4eae-86f0-d10cacaa0e95
Bohaty, S.M.
7d4cdf98-d06a-4d84-b2c6-d2cbb8592f91
Verosub, K.L.
71b9c710-71e8-4579-b6c8-5f19c5b1f8f3

Wilson, G.S., Roberts, A.P., Harwood, D.M., Fielding, C.R., Watkins, D.K., Naish, T.R., Florindo, F., Sagnotti, L., Scherer, R.P., Villa, G., Lavelle, M., McIntosh, W.C., Bohaty, S.M. and Verosub, K.L. (2002) Integrated chronostratigraphic calibration of the Oligocene-Miocene boundary at 24.0 ± 0.1 Ma from the CRP-2A drill core, Ross Sea, Antarctica. Geology, 30 (11), 1043-1046. (doi:10.1130/0091-7613(2002)030<1043:ICCOTO>2.0.CO;2).

Record type: Article

Abstract

An expanded Oligocene-Miocene boundary interval recovered in the Cape Roberts Project CRP-2A core from beneath the Ross Sea, Antarctica, has yielded a high-resolution integrated chrono stratigraphy that has, in turn, enabled a new, more direct, calibration of magnetic polarity and biostratigraphic events. The Oligocene-Miocene boundary interval in the CRP-2A core comprises three 60-m-thick, rapidly deposited (>0.5 m/k.y.) sedimentary sequences (sequences 9, 10, and 11). In sequences 10 and 11, single-crystal, laser-fusion 40Ar/39Ar analyses of anorthoclase phenocrysts from two tephra horizons independently calibrate the CRP-2A magnetic-polarity stratigraphy and age model. Sequences 10 and 11 encompass subchron C6Cn.3n, which is dated as 24.3 ± 0.1 to 24.16 ± 0.1 Ma. Sequence 9 is interpreted to encompass subchron C6Cn.2n and the Oligocene-Miocene boundary, which is dated as 24.0 ± 0.1 Ma. These ages are 0.2 m.y. older than those of the geomagnetic polarity time scale calibrated from seafloor-spreading ridges and 0.9–1.3 m.y. older than the newly proposed astronomically calibrated ages. We contend that the discrepancy with the astronomically calibrated ages arises from a mismatch of three 406 k.y. eccentricity cycles or a 1.2 m.y. modulation of obliquity amplitude in the astronomical calibration of the Oligocene–Miocene time scale.

Text
54._Wilson_et_al._Geology_PUB_VERSION.pdf - Other
Restricted to Repository staff only

More information

Published date: 2002
Keywords: chronostratigraphy, isotope dating, Antarctica, biostratigraphy, Cape Roberts Project

Identifiers

Local EPrints ID: 45395
URI: http://eprints.soton.ac.uk/id/eprint/45395
ISSN: 0091-7613
PURE UUID: 23069212-97db-4924-ba28-076dc07946af

Catalogue record

Date deposited: 27 Mar 2007
Last modified: 15 Mar 2024 09:10

Export record

Altmetrics

Contributors

Author: G.S. Wilson
Author: A.P. Roberts
Author: D.M. Harwood
Author: C.R. Fielding
Author: D.K. Watkins
Author: T.R. Naish
Author: F. Florindo
Author: L. Sagnotti
Author: R.P. Scherer
Author: G. Villa
Author: M. Lavelle
Author: W.C. McIntosh
Author: S.M. Bohaty
Author: K.L. Verosub

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×