Multiproxy reduced-dimension reconstruction of Pliocene Equatorial Pacific sea surface temperatures and precipitation over India and southeastern United States

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Author(s): Rajagopalan, Balaji; Wycech, Jody; Thomas, Marchitto; Molnar, Peter H.
Author Affiliation(s): Primary:
University of Colorado at Boulder, Department of Civil, Environmental and Architectural Engineering and Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States
Volume Title: AGU 2018 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2018; American Geophysical Union 2018 fall meeting, Washington, DC, Dec. 10-14, 2018. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The Pliocene (5.3-2.6 Ma) is the most recent time interval in Earth history when global climate was significantly warmer than the present, and as such is considered a potential analog to climate conditions predicted for the latter part of this century. A controversial aspect of the Pliocene climate system is a posited permanent El Nino-like state, which is largely inferred from sea-surface temperatures (SST) reconstructed from several sites in the equatorial Pacific. However, few studies investigate temperature and precipitation signatures of Pliocene El Nino Southern Oscillation (ENSO) in distal regions that are atmospherically teleconnected to ENSO during the modern period. For example, India experiences a weaker summer monsoon while the southeastern United States experiences cooler and wetter conditions during modern El Nino events. Quantitative estimates of these climate variables during Pliocene will provide comprehensive insights into the spatial and temporal variability of ENSO and precipitation during Pliocene. Motivated by this, we first present new foraminiferal (Trilobatus sacculifer) Mg/Ca-derived Pliocene SST records from Ocean Drilling Program sites in the Gulf of Mexico (Site 625), northwestern Atlantic (Site 997), and Bay of Bengal (Site U1447). We then utilize a multiproxy reduced-dimension methodology that combines these three new records with a compilation of previously published SST records from globally-distributed sites to reconstruct spatial and temporal snapshots of equatorial Pacific SSTs, consequently the ENSO state, and precipitation over India and the southeastern United States from 6 to 2 Ma. Relationships between dominant modes of spatial and temporal patterns of equatorial SST and regional precipitation at these locations with the modes of SST at the multiproxy locations during the modern period are developed using multivariate statistical techniques. These relationships are then used to reconstruct the climate fields during Pliocene. The use of this statistical approach provides a novel and robust test for Pliocene permanent El Nino.
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Andaman Sea; Atlantic Ocean; Blake-Bahama Outer Ridge; Cenozoic; Eastern U.S.; Equatorial Pacific; Expedition 353; Gulf of Mexico; IODP Site U1447; Indian Ocean; International Ocean Discovery Program; Leg 100; Leg 164; Neogene; North Atlantic; ODP Site 625; ODP Site 997; Ocean Drilling Program; Pacific Ocean; Paleo-oceanography; Paleocirculation; Pliocene; Sea-surface temperature; Southeastern U.S.; Tertiary; United States
Coordinates: N284954 N284954 W0870936 W0870936
N315035 N315035 W0752807 W0752807
N104724 N104724 E0930001 E0930000
Record ID: 2019044397
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