New biostratigraphic, magnetostratigraphic and isotopic insights into the Middle Eocene Climatic Optimum in low latitudes

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New biostratigraphic, magnetostratigraphic and isotopic insights into the Middle Eocene Climatic Optimum in low latitudes. / Edgar, K. M.; Wilson, P. A.; Sexton, P. F.; Gibbs, S. J.; Roberts, A. P.; Norris, R. D.

In: Palaeogeography Palaeoclimatology Palaeoecology, Vol. 297, No. 3-4, 20.11.2010, p. 670-682.

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Edgar, K. M. ; Wilson, P. A. ; Sexton, P. F. ; Gibbs, S. J. ; Roberts, A. P. ; Norris, R. D. / New biostratigraphic, magnetostratigraphic and isotopic insights into the Middle Eocene Climatic Optimum in low latitudes. In: Palaeogeography Palaeoclimatology Palaeoecology. 2010 ; Vol. 297, No. 3-4. pp. 670-682.

Bibtex

@article{3d48deb595764fe6962b5fafae0c4f9a,
title = "New biostratigraphic, magnetostratigraphic and isotopic insights into the Middle Eocene Climatic Optimum in low latitudes",
abstract = "The Middle Eocene Climatic Optimum (MECO) was a warming event that interrupted the long-term Eocene cooling trend. While this event is well documented at high southern and mid-latitudes, it is poorly known from low latitudes and its timing and duration are not well constrained because of problems of hiati, microfossil preservation and weak magnetic polarity in key sedimentary sections. Here, we report the results of a study designed to improve the bio-, magneto- and chemostratigraphy of the MECO interval using high-resolution records from two low-latitude sections in the Atlantic Ocean, Ocean Drilling Program (ODP) Sites 1051 and 1260. We present the first detailed benthic foraminiferal stable isotope records of the MECO from the low latitudes as well as the biostratigraphic counts of Orbulinoides beckmanni and new magnetostrati-graphic results. Our data demonstrate a similar to 750 kyr-long duration for the MECO characterized by increasing delta(13)C and decreasing 6180, with minimum 6180 values lasting similar to 40 kyr at 40.1 Ma coincident with a short-lived negative delta(13)C excursion. Thereafter, 6180 and delta(13)C values recover rapidly. The shift to minimum 6180 values at 40.1 Ma is coincident with a marked increase in the abundance of the planktonic foraminifera O. beckmanni, consistent with its inferred warm-water preference. O. beckmanni is an important Eocene biostratigraphic marker, defining planktonic foraminiferal Zone E12 with its lowest and highest occurrences (LO and HOs). Our new records reveal that the LO of O. beckmanni is distinctly diachronous, appearing similar to 500 kyr earlier in the equatorial Atlantic than in the subtropics (40.5 versus 41.0 Ma). We also show that, at both sites, the HO of O. beckmanni at 39.5 Ma is younger than the published calibrations, increasing the duration of Zone E12 by at least 400 kyr. In accordance with the tropical origins of O. beckmanni, this range expansion to higher latitudes may have occurred in response to sea surface warming during the MECO and subsequently disappeared with cooling of surface waters. (C) 2010 Elsevier B.V. All rights reserved.",
keywords = "Middle Eocene Climatic Optimum, Site 1051, Site 1260, Planktonic foraminifera, Biostratigraphy, Magnetostratigraphy, PALEOCENE THERMAL MAXIMUM, FORAMINIFERAL BIOSTRATIGRAPHY, PLANKTONIC-FORAMINIFERA, MAGNETIC STRATIGRAPHY, EVENTS, CALIBRATION, SEDIMENTS, PACIFIC, GUBBIO, CORES",
author = "Edgar, {K. M.} and Wilson, {P. A.} and Sexton, {P. F.} and Gibbs, {S. J.} and Roberts, {A. P.} and Norris, {R. D.}",
year = "2010",
month = nov,
day = "20",
doi = "10.1016/j.palaeo.2010.09.016",
language = "English",
volume = "297",
pages = "670--682",
journal = "Palaeogeography Palaeoclimatology Palaeoecology",
issn = "0031-0182",
publisher = "Elsevier",
number = "3-4",

}

RIS

TY - JOUR

T1 - New biostratigraphic, magnetostratigraphic and isotopic insights into the Middle Eocene Climatic Optimum in low latitudes

AU - Edgar, K. M.

AU - Wilson, P. A.

AU - Sexton, P. F.

AU - Gibbs, S. J.

AU - Roberts, A. P.

AU - Norris, R. D.

PY - 2010/11/20

Y1 - 2010/11/20

N2 - The Middle Eocene Climatic Optimum (MECO) was a warming event that interrupted the long-term Eocene cooling trend. While this event is well documented at high southern and mid-latitudes, it is poorly known from low latitudes and its timing and duration are not well constrained because of problems of hiati, microfossil preservation and weak magnetic polarity in key sedimentary sections. Here, we report the results of a study designed to improve the bio-, magneto- and chemostratigraphy of the MECO interval using high-resolution records from two low-latitude sections in the Atlantic Ocean, Ocean Drilling Program (ODP) Sites 1051 and 1260. We present the first detailed benthic foraminiferal stable isotope records of the MECO from the low latitudes as well as the biostratigraphic counts of Orbulinoides beckmanni and new magnetostrati-graphic results. Our data demonstrate a similar to 750 kyr-long duration for the MECO characterized by increasing delta(13)C and decreasing 6180, with minimum 6180 values lasting similar to 40 kyr at 40.1 Ma coincident with a short-lived negative delta(13)C excursion. Thereafter, 6180 and delta(13)C values recover rapidly. The shift to minimum 6180 values at 40.1 Ma is coincident with a marked increase in the abundance of the planktonic foraminifera O. beckmanni, consistent with its inferred warm-water preference. O. beckmanni is an important Eocene biostratigraphic marker, defining planktonic foraminiferal Zone E12 with its lowest and highest occurrences (LO and HOs). Our new records reveal that the LO of O. beckmanni is distinctly diachronous, appearing similar to 500 kyr earlier in the equatorial Atlantic than in the subtropics (40.5 versus 41.0 Ma). We also show that, at both sites, the HO of O. beckmanni at 39.5 Ma is younger than the published calibrations, increasing the duration of Zone E12 by at least 400 kyr. In accordance with the tropical origins of O. beckmanni, this range expansion to higher latitudes may have occurred in response to sea surface warming during the MECO and subsequently disappeared with cooling of surface waters. (C) 2010 Elsevier B.V. All rights reserved.

AB - The Middle Eocene Climatic Optimum (MECO) was a warming event that interrupted the long-term Eocene cooling trend. While this event is well documented at high southern and mid-latitudes, it is poorly known from low latitudes and its timing and duration are not well constrained because of problems of hiati, microfossil preservation and weak magnetic polarity in key sedimentary sections. Here, we report the results of a study designed to improve the bio-, magneto- and chemostratigraphy of the MECO interval using high-resolution records from two low-latitude sections in the Atlantic Ocean, Ocean Drilling Program (ODP) Sites 1051 and 1260. We present the first detailed benthic foraminiferal stable isotope records of the MECO from the low latitudes as well as the biostratigraphic counts of Orbulinoides beckmanni and new magnetostrati-graphic results. Our data demonstrate a similar to 750 kyr-long duration for the MECO characterized by increasing delta(13)C and decreasing 6180, with minimum 6180 values lasting similar to 40 kyr at 40.1 Ma coincident with a short-lived negative delta(13)C excursion. Thereafter, 6180 and delta(13)C values recover rapidly. The shift to minimum 6180 values at 40.1 Ma is coincident with a marked increase in the abundance of the planktonic foraminifera O. beckmanni, consistent with its inferred warm-water preference. O. beckmanni is an important Eocene biostratigraphic marker, defining planktonic foraminiferal Zone E12 with its lowest and highest occurrences (LO and HOs). Our new records reveal that the LO of O. beckmanni is distinctly diachronous, appearing similar to 500 kyr earlier in the equatorial Atlantic than in the subtropics (40.5 versus 41.0 Ma). We also show that, at both sites, the HO of O. beckmanni at 39.5 Ma is younger than the published calibrations, increasing the duration of Zone E12 by at least 400 kyr. In accordance with the tropical origins of O. beckmanni, this range expansion to higher latitudes may have occurred in response to sea surface warming during the MECO and subsequently disappeared with cooling of surface waters. (C) 2010 Elsevier B.V. All rights reserved.

KW - Middle Eocene Climatic Optimum

KW - Site 1051

KW - Site 1260

KW - Planktonic foraminifera

KW - Biostratigraphy

KW - Magnetostratigraphy

KW - PALEOCENE THERMAL MAXIMUM

KW - FORAMINIFERAL BIOSTRATIGRAPHY

KW - PLANKTONIC-FORAMINIFERA

KW - MAGNETIC STRATIGRAPHY

KW - EVENTS

KW - CALIBRATION

KW - SEDIMENTS

KW - PACIFIC

KW - GUBBIO

KW - CORES

U2 - 10.1016/j.palaeo.2010.09.016

DO - 10.1016/j.palaeo.2010.09.016

M3 - Article

VL - 297

SP - 670

EP - 682

JO - Palaeogeography Palaeoclimatology Palaeoecology

JF - Palaeogeography Palaeoclimatology Palaeoecology

SN - 0031-0182

IS - 3-4

ER -