The University of Southampton
University of Southampton Institutional Repository
Warning ePrints Soton is experiencing an issue with some file downloads not being available. We are working hard to fix this. Please bear with us.

The Eocene and Oligocene Pacific equatorial region from ODP Leg 199 drilling (abstract of paper presented at AGU Fall Meeting, San Francisco, 6-10 Dec 2002)

The Eocene and Oligocene Pacific equatorial region from ODP Leg 199 drilling (abstract of paper presented at AGU Fall Meeting, San Francisco, 6-10 Dec 2002)
The Eocene and Oligocene Pacific equatorial region from ODP Leg 199 drilling (abstract of paper presented at AGU Fall Meeting, San Francisco, 6-10 Dec 2002)
ODP Leg 199 drilled a latitudinal transect of sites across the position of the early Eocene equator, designed to study the evolution of the equatorial Pacific current and wind system as the Earth went from maximum Cenozoic warmth to initial Antarctic glaciations. The cruise recovered a biogenic sedimentary record of equatorial processes from the early Miocene to the late Paleocene, roughly from 18 to 56 Ma. Above the biogenic sediments are 10 m or more of nonfossiliferous clay, representing most of the Neogene interval.
We found that equatorial deposition patterns were stable for the Eocene but very different from those of the Neogene. The Eocene is marked by a very shallow carbonate compensation depth (CCD) and radiolarian ooze sediments. In contrast, Pleistocene equatorial sediments are carbonate and diatom rich. The Eocene equatorial sedimentation regime was also much wider than modern, expanding in the middle Eocene to about 10 degrees north of the paleoequator. We interpret the Eocene sedimentary environment to indicate significantly more diffuse upwelling than is found in the modern ocean and a deeper-than-modern eastern Pacific thermocline. Eocene deep waters appear to have been well-oxygenated despite being much warmer than modern deep waters .
There is an abrupt sedimentological transition coincident with the first major glaciation of Antarctica in the early Oligocene from Eocene equatorial conditions to proto-modern conditions. Over a time period of about 120 kyr the CCD dropped by more than 1.3 km and sedimentation focused into a narrow equatorial band similar to equatorial sedimentation in the Holocene equatorial Pacific. We interpret the change to mark the first Cenozoic appearance of the modern Pacific equatorial upwelling system.
We also recovered examples of the Paleocene-Eocene boundary at 3 different drillsites from about 1 degree south of the 55 Ma paleoequator to 11 degrees north of it. The P-E boundary event, one of the largest carbon-isotope excursions of the Cenozoic, is represented by a carbonate-poor multi-colored sediment interval. Consistent banding between two sites more than 200 km apart suggest significant changes in deep ocean chemistry during this time interval.
0096-3941
p.F946
Lyle, M.
32ca0536-0600-4193-bc16-70fbe8c99dd6
Wilson, P.A.
f940a9f0-fa5a-4a64-9061-f0794bfbf7c6
Janecek, T.R.
cb111528-5025-48fe-a999-35ee27d2643c
Backman, J.
b2d77581-60c6-44fd-b61e-9dfbd85f2a8f
Busch, W.H.
d9359d43-f3f6-4b3c-bf42-7a5aa03bb988
Coxall, H.K.
5de02922-b619-4e86-b7ba-373b8569716a
Faul, K.
51d38cd0-209f-4bf3-82da-21afefd791f2
Gaillot, P.
e02ae278-5e9b-49d2-8a69-0e1178242ee6
Hovan, S.A.
4db809d5-5998-452e-8fbc-5d97b3f864fc
Knoop, P.
39747243-531b-45ec-b24e-b35a475e8152
Kruse, S.
0239ee82-29f9-4407-bf1e-88b6922ff726
Lanci, L.
0905f57d-d835-49c9-9356-efc950a171db
Lear, C.H.
112c634b-d610-4413-ad3d-5991b454593e
Moore, T.C. Jnr.
d6521e67-522a-4d94-a354-7dd17d0d79b3
Nigrini, C.A.
d441b7ac-92d1-4740-8d52-757efe6b1a7b
Nishi, H.
c60453b0-21bc-41e4-b576-7a2b6ecfb7ce
Nomura, R.
484a31d7-1be2-4286-8bb6-76da13b119f6
Norris, R.D.
81ac4a17-2a84-4c7c-9c02-c9f14bb2695e
Pälike, H.
b9bf7798-ad8c-479b-8487-dd9a30a61fa5
Parés, J.M.
2d4ed8d8-fc18-4e93-b566-a359623c99ea
Quintin, L.
0c0f2f23-2248-4aaa-a55b-ce0c9f7bb720
Raffi, I.
5cd0b487-3cdc-48e6-894c-2bbf5c59ae02
Rea, B.R.
8d964c93-27ee-4aeb-8e39-b9fc8f06985a
Rea, D.K.
6e297131-e1f7-4dd4-96ce-2895853ddbe0
Steiger, T.H.
3b42f7f3-256c-4cea-a25a-a2306135b0e6
Tripati, A.K.
39b60a55-55e5-41fd-8c4d-d235ff4a0087
Vanden Berg, M.D.
6977449f-5441-41e6-acf4-8edf8b003fa1
Wade, B.S.
4caf9386-0e3f-479b-a491-6c8dff99dad1
Lyle, M.
32ca0536-0600-4193-bc16-70fbe8c99dd6
Wilson, P.A.
f940a9f0-fa5a-4a64-9061-f0794bfbf7c6
Janecek, T.R.
cb111528-5025-48fe-a999-35ee27d2643c
Backman, J.
b2d77581-60c6-44fd-b61e-9dfbd85f2a8f
Busch, W.H.
d9359d43-f3f6-4b3c-bf42-7a5aa03bb988
Coxall, H.K.
5de02922-b619-4e86-b7ba-373b8569716a
Faul, K.
51d38cd0-209f-4bf3-82da-21afefd791f2
Gaillot, P.
e02ae278-5e9b-49d2-8a69-0e1178242ee6
Hovan, S.A.
4db809d5-5998-452e-8fbc-5d97b3f864fc
Knoop, P.
39747243-531b-45ec-b24e-b35a475e8152
Kruse, S.
0239ee82-29f9-4407-bf1e-88b6922ff726
Lanci, L.
0905f57d-d835-49c9-9356-efc950a171db
Lear, C.H.
112c634b-d610-4413-ad3d-5991b454593e
Moore, T.C. Jnr.
d6521e67-522a-4d94-a354-7dd17d0d79b3
Nigrini, C.A.
d441b7ac-92d1-4740-8d52-757efe6b1a7b
Nishi, H.
c60453b0-21bc-41e4-b576-7a2b6ecfb7ce
Nomura, R.
484a31d7-1be2-4286-8bb6-76da13b119f6
Norris, R.D.
81ac4a17-2a84-4c7c-9c02-c9f14bb2695e
Pälike, H.
b9bf7798-ad8c-479b-8487-dd9a30a61fa5
Parés, J.M.
2d4ed8d8-fc18-4e93-b566-a359623c99ea
Quintin, L.
0c0f2f23-2248-4aaa-a55b-ce0c9f7bb720
Raffi, I.
5cd0b487-3cdc-48e6-894c-2bbf5c59ae02
Rea, B.R.
8d964c93-27ee-4aeb-8e39-b9fc8f06985a
Rea, D.K.
6e297131-e1f7-4dd4-96ce-2895853ddbe0
Steiger, T.H.
3b42f7f3-256c-4cea-a25a-a2306135b0e6
Tripati, A.K.
39b60a55-55e5-41fd-8c4d-d235ff4a0087
Vanden Berg, M.D.
6977449f-5441-41e6-acf4-8edf8b003fa1
Wade, B.S.
4caf9386-0e3f-479b-a491-6c8dff99dad1

Lyle, M., Wilson, P.A., Janecek, T.R., Backman, J., Busch, W.H., Coxall, H.K., Faul, K., Gaillot, P., Hovan, S.A., Knoop, P., Kruse, S., Lanci, L., Lear, C.H., Moore, T.C. Jnr., Nigrini, C.A., Nishi, H., Nomura, R., Norris, R.D., Pälike, H., Parés, J.M., Quintin, L., Raffi, I., Rea, B.R., Rea, D.K., Steiger, T.H., Tripati, A.K., Vanden Berg, M.D. and Wade, B.S. (2002) The Eocene and Oligocene Pacific equatorial region from ODP Leg 199 drilling (abstract of paper presented at AGU Fall Meeting, San Francisco, 6-10 Dec 2002). EOS: Transactions American Geophysical Union, 83 (47, Supplement), p.F946.

Record type: Article

Abstract

ODP Leg 199 drilled a latitudinal transect of sites across the position of the early Eocene equator, designed to study the evolution of the equatorial Pacific current and wind system as the Earth went from maximum Cenozoic warmth to initial Antarctic glaciations. The cruise recovered a biogenic sedimentary record of equatorial processes from the early Miocene to the late Paleocene, roughly from 18 to 56 Ma. Above the biogenic sediments are 10 m or more of nonfossiliferous clay, representing most of the Neogene interval.
We found that equatorial deposition patterns were stable for the Eocene but very different from those of the Neogene. The Eocene is marked by a very shallow carbonate compensation depth (CCD) and radiolarian ooze sediments. In contrast, Pleistocene equatorial sediments are carbonate and diatom rich. The Eocene equatorial sedimentation regime was also much wider than modern, expanding in the middle Eocene to about 10 degrees north of the paleoequator. We interpret the Eocene sedimentary environment to indicate significantly more diffuse upwelling than is found in the modern ocean and a deeper-than-modern eastern Pacific thermocline. Eocene deep waters appear to have been well-oxygenated despite being much warmer than modern deep waters .
There is an abrupt sedimentological transition coincident with the first major glaciation of Antarctica in the early Oligocene from Eocene equatorial conditions to proto-modern conditions. Over a time period of about 120 kyr the CCD dropped by more than 1.3 km and sedimentation focused into a narrow equatorial band similar to equatorial sedimentation in the Holocene equatorial Pacific. We interpret the change to mark the first Cenozoic appearance of the modern Pacific equatorial upwelling system.
We also recovered examples of the Paleocene-Eocene boundary at 3 different drillsites from about 1 degree south of the 55 Ma paleoequator to 11 degrees north of it. The P-E boundary event, one of the largest carbon-isotope excursions of the Cenozoic, is represented by a carbonate-poor multi-colored sediment interval. Consistent banding between two sites more than 200 km apart suggest significant changes in deep ocean chemistry during this time interval.

Text
agu2002_lw.pdf - Other
Download (86kB)
Text
agu2002_lw.html - Other
Download (4kB)

More information

Published date: 2002

Identifiers

Local EPrints ID: 41879
URI: http://eprints.soton.ac.uk/id/eprint/41879
ISSN: 0096-3941
PURE UUID: 112b87a7-04c8-4f18-9c98-7f2891ae23b5

Catalogue record

Date deposited: 17 Oct 2006
Last modified: 19 Nov 2021 20:03

Export record

Contributors

Author: M. Lyle
Author: P.A. Wilson
Author: T.R. Janecek
Author: J. Backman
Author: W.H. Busch
Author: H.K. Coxall
Author: K. Faul
Author: P. Gaillot
Author: S.A. Hovan
Author: P. Knoop
Author: S. Kruse
Author: L. Lanci
Author: C.H. Lear
Author: T.C. Jnr. Moore
Author: C.A. Nigrini
Author: H. Nishi
Author: R. Nomura
Author: R.D. Norris
Author: H. Pälike
Author: J.M. Parés
Author: L. Quintin
Author: I. Raffi
Author: B.R. Rea
Author: D.K. Rea
Author: T.H. Steiger
Author: A.K. Tripati
Author: M.D. Vanden Berg
Author: B.S. Wade

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.

×