Changes in the east-west contrast of the upper Equatorial Pacific Ocean over the last 10 Ma

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http://meetingorganizer.copernicus.org/EGU2016/EGU2016-15549.pdf
Author(s): Rousselle, Gabrielle; Beltran, Catherine; Sicre, Marie-Alexandrine; de Rafélis, Marc; Schouten, Stefan
Author Affiliation(s): Primary:
Université Pierre et Marie Curie, ISTeP, Paris, France
Other:
Géosciences Environnements Toulouse, France
Royal Netherlands Institute for Sea Research, Netherlands
Volume Title: European Geosciences Union general assembly 2016
Source: Geophysical Research Abstracts, Vol.18; European Geosciences Union general assembly 2016, Vienna, Austria, April 17-22, 2016. Publisher: Copernicus GmbH on behalf of the European Geosciences Union (EGU), Katlenburg-Lindau, Germany. ISSN: 1029-7006
Note: In English
Summary: This study presents new data of the past 10 Ma climate in the Equatorial Pacific. Combining UK'37 and TEX86-derived temperatures as well as carbon and oxygen isotope of calcifying planktonic species living in surface and subsurface waters at the IODP site U1338 (Eastern Equatorial Pacific) and 806 (Western Equatorial Pacific) we investigate the temporal evolution of the zonal gradient across the equatorial Pacific. This multi-proxy approach is used to reconstruct changes in the asymmetric pattern between the Eastern and Western Equatorial Pacific surface and thermocline depth waters. Based on the cross-analysis of our data and those available in the literature we propose a schematic view of long-term La Niña- and El Niño-like alternations from the upper Miocene in the equatorial Pacific Ocean. We suggest a general shoaling of the thermocline along the equator from about 11 Ma ago demonstrate that this shoaling is linked to the equatorial upwelling and the establishment of the Eastern Pacific Cold tongue particularly discernible during three time intervals referring to La Niña-like periods (11.5-9 Ma, 6.8-6 Ma and 4.8-1.4 Ma). Our study also reveals intervals of weakened oceanic circulation during El Niño-like periods (9-6.8 Ma and 6-4.8 Ma). The role of global ice sheet, the Indonesian seaway restriction and the Central American seaway closure as driving factors of the observed changes are discussed. [Copyright Author(s) 2016. CC Attribution 3.0 License: https://creativecommons.org/licenses/by/3.0/legalcode]
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; C-13/C-12; Carbon; Cenozoic; Chemostratigraphy; Cores; Depositional environment; East Pacific; El Nino; Equatorial Pacific; Expedition 321; Expeditions 320/321; IODP Site U1338; Integrated Ocean Drilling Program; Isotope ratios; Isotopes; La Nina; Leg 130; Lithofacies; Lithostratigraphy; Neogene; North Pacific; Northeast Pacific; Northwest Pacific; O-18/O-16; ODP Site 806; Ocean Drilling Program; Ontong Java Plateau; Oxygen; Pacific Equatorial Age Transect; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Reconstruction; Stable isotopes; TEX86; Tertiary; West Pacific
Coordinates: N023028 N023028 W1175811 W1175811
N001906 N001907 E1592142 E1592140
Record ID: 2019065053
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from European Geosciences Union, Munich, Germany