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.

A warm, stratified, and restricted Labrador Sea across the Middle Eocene and its climatic optimum

A warm, stratified, and restricted Labrador Sea across the Middle Eocene and its climatic optimum
A warm, stratified, and restricted Labrador Sea across the Middle Eocene and its climatic optimum

Several studies indicate that North Atlantic Deep Water (NADW) formation might have initiated during the globally warm Eocene (56–34 Ma). However, constraints on Eocene surface ocean conditions in source regions presently conducive to deep water formation are sparse. Here we test whether ocean conditions of the middle Eocene Labrador Sea might have allowed for deep water formation by applying (organic) geochemical and palynological techniques, on sediments from Ocean Drilling Program (ODP) Site 647. We reconstruct a long‐term sea surface temperature (SST) drop from ~30°C to ~27°C between 41.5 to 38.5 Ma, based on TEX86. Superimposed on this trend, we record ~2°C warming in SST associated with the Middle Eocene Climatic Optimum (MECO; ~40 Ma), which is the northernmost MECO record as yet, and another, likely regional, warming phase at ~41.1 Ma, associated with low‐latitude planktic foraminifera and dinoflagellate cyst incursions. Dinoflagellate cyst assemblages together with planktonic foraminiferal stable oxygen isotope ratios overall indicate low surface water salinities and strong stratification. Benthic foraminifer stable carbon and oxygen isotope ratios differ from global deep ocean values by 1–2‰ and 2–4‰, respectively, indicating geographic basin isolation. Our multiproxy reconstructions depict a consistent picture of relatively warm and fresh but also highly variable surface ocean conditions in the middle Eocene Labrador Sea. These conditions were unlikely conducive to deep water formation. This implies either NADW did not yet form during the middle Eocene or it formed in a different source region and subsequently bypassed the southern Labrador Sea.
2572-4517
Cramwinckel, Margot J.
e467976c-be0c-47a5-a7eb-ecfe93048373
Coxall, Helen K.
aeeac8f5-cc62-4861-8805-4a2027b33b6c
Śliwińska, Kasia K.
74ef9b8d-9063-423a-973b-4d580751d489
Polling, Marcel
2840ca14-01e1-4737-ad7d-1d258d5c9672
Harper, Dustin T.
545e1065-ecb8-4176-a11d-cfa06bea7b8b
Bijl, Peter K.
fe283896-4066-490e-81b5-3212d00ef810
Brinkhuis, Henk
2897d110-84de-4cd1-8b90-97a0bc404354
Eldrett, James S.
b690fad3-9a08-4abb-bfe5-39b1c8c43ae9
Houben, Alexander J. P.
1e632e5c-84f8-4713-a8b4-b5bddeadf283
Peterse, Francien
471cf1d7-57d4-4954-ae8d-14fa03f0278b
Schouten, Stefan
0d0291ca-b8dc-48a2-b61c-798c650ec1fd
Reichart, Gert‐jan
f56639e3-dd16-4dfc-941e-d55302ef9ee5
Zachos, James C.
c262d59f-aadc-4e09-b844-098db9a0e3c5
Sluijs, Appy
af623507-b795-4458-8ca5-cce783869a3d
Cramwinckel, Margot J.
e467976c-be0c-47a5-a7eb-ecfe93048373
Coxall, Helen K.
aeeac8f5-cc62-4861-8805-4a2027b33b6c
Śliwińska, Kasia K.
74ef9b8d-9063-423a-973b-4d580751d489
Polling, Marcel
2840ca14-01e1-4737-ad7d-1d258d5c9672
Harper, Dustin T.
545e1065-ecb8-4176-a11d-cfa06bea7b8b
Bijl, Peter K.
fe283896-4066-490e-81b5-3212d00ef810
Brinkhuis, Henk
2897d110-84de-4cd1-8b90-97a0bc404354
Eldrett, James S.
b690fad3-9a08-4abb-bfe5-39b1c8c43ae9
Houben, Alexander J. P.
1e632e5c-84f8-4713-a8b4-b5bddeadf283
Peterse, Francien
471cf1d7-57d4-4954-ae8d-14fa03f0278b
Schouten, Stefan
0d0291ca-b8dc-48a2-b61c-798c650ec1fd
Reichart, Gert‐jan
f56639e3-dd16-4dfc-941e-d55302ef9ee5
Zachos, James C.
c262d59f-aadc-4e09-b844-098db9a0e3c5
Sluijs, Appy
af623507-b795-4458-8ca5-cce783869a3d

Cramwinckel, Margot J., Coxall, Helen K., Śliwińska, Kasia K., Polling, Marcel, Harper, Dustin T., Bijl, Peter K., Brinkhuis, Henk, Eldrett, James S., Houben, Alexander J. P., Peterse, Francien, Schouten, Stefan, Reichart, Gert‐jan, Zachos, James C. and Sluijs, Appy (2020) A warm, stratified, and restricted Labrador Sea across the Middle Eocene and its climatic optimum. Paleoceanography and Paleoclimatology, 35 (10), [e2020PA003932]. (doi:10.1029/2020PA003932).

Record type: Article

Abstract


Several studies indicate that North Atlantic Deep Water (NADW) formation might have initiated during the globally warm Eocene (56–34 Ma). However, constraints on Eocene surface ocean conditions in source regions presently conducive to deep water formation are sparse. Here we test whether ocean conditions of the middle Eocene Labrador Sea might have allowed for deep water formation by applying (organic) geochemical and palynological techniques, on sediments from Ocean Drilling Program (ODP) Site 647. We reconstruct a long‐term sea surface temperature (SST) drop from ~30°C to ~27°C between 41.5 to 38.5 Ma, based on TEX86. Superimposed on this trend, we record ~2°C warming in SST associated with the Middle Eocene Climatic Optimum (MECO; ~40 Ma), which is the northernmost MECO record as yet, and another, likely regional, warming phase at ~41.1 Ma, associated with low‐latitude planktic foraminifera and dinoflagellate cyst incursions. Dinoflagellate cyst assemblages together with planktonic foraminiferal stable oxygen isotope ratios overall indicate low surface water salinities and strong stratification. Benthic foraminifer stable carbon and oxygen isotope ratios differ from global deep ocean values by 1–2‰ and 2–4‰, respectively, indicating geographic basin isolation. Our multiproxy reconstructions depict a consistent picture of relatively warm and fresh but also highly variable surface ocean conditions in the middle Eocene Labrador Sea. These conditions were unlikely conducive to deep water formation. This implies either NADW did not yet form during the middle Eocene or it formed in a different source region and subsequently bypassed the southern Labrador Sea.

Text
2020PA003932 - Version of Record
Available under License Creative Commons Attribution.
Download (11MB)

More information

Accepted/In Press date: 29 July 2020
Published date: 9 October 2020

Identifiers

Local EPrints ID: 445138
URI: http://eprints.soton.ac.uk/id/eprint/445138
ISSN: 2572-4517
PURE UUID: 05124b1b-021b-4af6-b2bc-62c4d16f0a6f
ORCID for Margot J. Cramwinckel: ORCID iD orcid.org/0000-0002-6063-836X

Catalogue record

Date deposited: 23 Nov 2020 17:30
Last modified: 26 Nov 2021 03:22

Export record

Altmetrics

Contributors

Author: Helen K. Coxall
Author: Kasia K. Śliwińska
Author: Marcel Polling
Author: Dustin T. Harper
Author: Peter K. Bijl
Author: Henk Brinkhuis
Author: James S. Eldrett
Author: Alexander J. P. Houben
Author: Francien Peterse
Author: Stefan Schouten
Author: Gert‐jan Reichart
Author: James C. Zachos
Author: Appy Sluijs

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.

×