High-resolution benthic foraminiferal δ18O and δ13C records of ODP Site 807 in the western Equatorial Pacific since 3.5 Ma and its response to the late Pliocene onset of the Northern Hemisphere glaciation

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Author(s): Feng Hua; Tian Jun
Author Affiliation(s): Primary:
Tongji University, Shanghai, China
Volume Title: European Geosciences Union general assembly 2019
Source: Geophysical Research Abstracts, Vol.21; European Geosciences Union general assembly 2019, Vienna, Austria, April 7-12, 2019. Publisher: Copernicus GmbH on behalf of the European Geosciences Union (EGU), Katlenburg-Lindau, Germany. ISSN: 1029-7006
Note: In English
Summary: We presented benthic foraminiferal δ18O and δ13C records of Ocean Drilling Program (ODP) Site 807 (3°36'N, 156°37'E, 2804m) in the western equatorial Pacific in 3.5-0 Ma by 1345 paired isotopic measurements, with a time resolution of 2.6 Kyr. The most significant event in benthic δ18O is a gradual increase of nearly 1.2ppm in 3.3-2.5 Ma (Tiedemann et al., 1994; Shackleton et al., 1995; Tian et al., 2002; Tian et al., 2006), which indicates the late Pliocene onset of the Northern Hemisphere Glaciation (NHG). Based on the benthic δ18O record of ODP Site 807 and other records from the Atlantic, the Eastern Pacific, the Indian Ocean and Southern Oceans, we tentatively discussed the response of benthic foraminiferal δ18O to the late Pliocene onset of the NHG. We carried out linear regression analyses on the benthic foraminiferal δ18O to investigate the amplitude of the variability of δ18O within the period between Marine Isotope Stages M2 and G6 (∼3.3-2.7 Ma). The deep water sites in the North Atlantic (DSDP (Deep Sea Drilling Program) Site 607(41°00'N, 32°58'W, 3427m), and ODP Site 659(18°05'N, 21°02'W, 3070m)) and the Southern Ocean (ODP Site 704(46° 53'S, 7°25'E, 2532m)) display the most significant increase in δ18O, while those in the western equatorial Pacific (ODP Site 807) and the Indian Ocean (ODP Site 758(5°23'N, 90°21'E, 2925m)) exhibit moderate increase in δ18O. ODP Site 982(57°31'N, 15°53'W, 1145m) in the North Atlantic intermediate water also exhibits relatively small increase in benthic foraminiferal δ18O. Both the sea surface temperature and bottom water temperature of ODP Site 982 show an increasing trend from 3.3 Ma to 2.7 Ma. The basin-to-basin difference in the responses of the benthic foraminiferal δ18O to the late Pliocene onset of the NHG probably reflect the status of the global Thermohaline Circulation (THC). We speculate that the production of the North Atlantic Deep Water (NADW) might became sluggish during this period, indicating a weakened Thermohaline Circulation. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]
Year of Publication: 2019
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; C-13/C-12; Cape Verde Rise; Carbon; Cenozoic; Chemostratigraphy; Cores; DSDP Site 607; Deep Sea Drilling Project; Equatorial Pacific; Foraminifera; Glaciation; IPOD; Indian Ocean; Isotope ratios; Isotopes; Leg 108; Leg 114; Leg 121; Leg 130; Leg 162; Leg 94; Marine sediments; Microfossils; Mid-Atlantic Ridge; Neogene; Ninetyeast Ridge; North Atlantic; North Pacific; Northeast Atlantic; Northwest Pacific; O-18/O-16; ODP Site 659; ODP Site 704; ODP Site 758; ODP Site 807; ODP Site 982; Ocean Drilling Program; Ocean circulation; Ontong Java Plateau; Oxygen; Pacific Ocean; Paleo-oceanography; Pliocene; Regression analysis; Rockall Bank; Sedimentary rocks; Sediments; South Atlantic; Stable isotopes; Statistical analysis; Tertiary; Thermohaline circulation; Upper Pliocene; West Pacific
Coordinates: N033622 N033626 E1563730 E1563728
N410004 N410005 W0325726 W0325727
N180437 N183438 W0210134 W0210135
S465246 S465245 E0072515 E0072515
N052302 N052303 E0902141 E0902140
N573100 N573100 W0155200 W0155200
Record ID: 2019050545
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from European Geosciences Union, Munich, Germany