Deglacial delta O-18 and hydrologic variability in the tropical Pacific and Indian Oceans

• Published in: Earth and Planetary Science Letters
• Main Authors: Gibbons, Fern T., Oppo, Delia W., Mohtadi, Mahyar, Rosenthal, Yair, Cheng, Jun, Liu, Zhengyu, Linsley, Braddock K.
• Other Authors: Gibbons, FT (reprint author), Nature Conservancy, 4245 North Fairfax Dr,Suite 100, Arlington, VA 22203 USA., Woods Hole Oceanog Inst, MIT WHOI Joint Program Oceanog, Woods Hole, MA 02543 USA., Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA., Univ Bremen, MARUM Zentrum Marine Umweltwissensch, D-28359 Bremen, Germany., Rutgers State Univ, Inst Marine & Coastal Sci, New Brunswick, NJ 08901 USA., Rutgers State Univ, Dept Geol, New Brunswick, NJ 08901 USA., Nanjing Univ Informat Sci & Technol, Sch Marine Sci, Nanjing 210044, Jiangsu, Peoples R China., Univ Wisconsin, Ctr Climate Res, Madison, WI 53706 USA., Univ Wisconsin, Dept Atmospher & Ocean Sci, Madison, WI 53706 USA., Peking Univ, Sch Phys, Lab Ocean Atmos Studies, Beijing 100871, Peoples R China., Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10694 USA., Nature Conservancy, 4245 North Fairfax Dr,Suite 100, Arlington, VA 22203 USA.
• Format: Journal/Newspaper
• Language: English
• Published: earth and planetary science letters 2014
• Subjects: Indo-Pacific; Eastern Equatorial Pacific; delta O-18 of seawater; deglaciation; heat transport; LAST GLACIAL MAXIMUM; OXYGEN ISOTOPIC COMPOSITION; HEINRICH EVENT 1; AUSTRALIAN-INDONESIAN MONSOON; SEA-SURFACE TEMPERATURE; NORTH-ATLANTIC; WARM POOL; CLIMATE-CHANGE; ASIAN MONSOON; EQUATORIAL PACIFIC; Indian; Pacific; North Atlantic
• Online Access: https://hdl.handle.net/20.500.11897/216281; https://doi.org/10.1016/j.epsl.2013.11.032

Evidence from geologic archives suggests that there were large changes in the tropical hydrologic cycle associated with the two prominent northern hemisphere deglacial cooling events, Heinrich Stadial 1 (HS1; similar to 19 to 15 kyr BP; kyr BP = 1000 yr before present) and the Younger Dryas (similar to 12.9 to 11.7 kyr BP). These hydrologic shifts have been alternatively attributed to high and low latitude origin. Here, we present a new record of hydrologic variability based on planktic foraminifera-derived delta O-18 of seawater (delta O-18(sw)) estimates from a sediment core from the tropical Eastern Indian Ocean, and using 12 additional delta O-18(sw) records, construct a single record of the dominant mode of tropical Eastern Equatorial Pacific and Indo-Pacific Warm Pool (IPWP) hydrologic variability. We show that deglacial hydrologic shifts parallel variations in the reconstructed interhemispheric temperature gradient, suggesting a strong response to variations in the Atlantic Meridional Overturning Circulation and the attendant heat redistribution. A transient model simulation of the last deglaciation suggests that hydrologic changes, including a southward shift in the Intertropical Convergence Zone (ITCZ) which likely occurred during these northern hemisphere cold events, coupled with oceanic advection and mixing, resulted in increased salinity in the Indonesian region of the IPWP and the eastern tropical Pacific, which is recorded by the delta O-18(sw) proxy. Based on our observations and modeling results we suggest the interhemispheric temperature gradient directly controls the tropical hydrologic cycle on these time scales, which in turn mediates poleward atmospheric heat transport. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved. Geochemistry & Geophysics SCI(E) EI 6 ARTICLE [e-mail] 240-251 387