Timing and pacing of Pliocene climate and paleoenvironmental change in southwestern Australia (IODP Exp. 356, Site U1459).

Author(s): De Vleeschouwer, David; Bogus, Kara; Auer, Gerald; Christensen, Beth Anne; Baranwal, Soma; Fulthorpe, Craig; Gallagher, Stephen J.; Groeneveld, Jeroen; Henderiks, Jorijntje; Mamo, Briony L.; Petrick, Benjamin
Author Affiliation(s): Primary:
University of Bremen, Palaeoceanography, Bremen, Germany
Other:
International Ocean Discovery Program, United States
University of Graz, Austria
Adelphi University, United States
Arctic University of Norway, Norway
University of Texas at Austin, United States
University of Melbourne, Australia
Uppsala University, Sweden
University of Hong Kong, China
Newcastle University, United Kingdom
Volume Title: AGU 2016 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2016; American Geophysical Union 2016 fall meeting, San Francisco, CA, Dec. 12-16, 2016. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The Pliocene Epoch was a globally-warm, high-CO2 period, which nevertheless experienced four globally-recognized glacial events (De Schepper et al., 2014). Brief (<100 kyr) but intense glacials interrupted the relatively warm Pliocene climate at 4.9, 4.0, 3.6 and 3.3 Ma. Different hypotheses exist to explain why these glaciation events were so intense, and why the global climate system returned to warm conditions relatively quickly. Some of these hypotheses ascribe a key-role to the Indonesian Throughflow, as a regulator of equator-to-pole heat transfer. IODP Site U1459 (28°40'S, 113°34'E; Perth Basin) lies directly seaward of the Houtman-Abrolhos main reef complex. The development of a reef complex at 28°S is possible because of the "modern" Leeuwin Current, which is mainly fed by the Indonesian Throughflow. The Leeuwin Current transports warm, low-salinity, nutrient-deficient water southward along the west coast of Australia. However, the Pliocene oceanography of southwest Australia and the possible influence of a Leeuwin-like current are not well known. Here, we present orbital scale elemental data, obtained by X-ray fluorescence (XRF) core scanning to provide insight into the long-term evolution of the Leeuwin Current. The XRF-derived calcium-iron ratio time-series exhibits two distinct minima, marking two intervals where the unlithified packstones and grainstones have relatively low carbonate content. These intervals are dated at ∼4.0 and ∼3.3 Ma and thus correspond with two globally-recognized Pliocene glaciation events. During these glacials, the equator-to-pole heat transfer was likely reduced due to a restriction of the Indonesian Throughflow, which could imply that Site U1459 was under the relatively stronger influence of a colder, northwards-flowing West Australian Current at ∼4.0 and ∼3.3 Ma. De Schepper, S., et al. (2014). "A global synthesis of the marine and terrestrial evidence for glaciation during the Pliocene Epoch." Earth-Science Reviews 135: 83-102.
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Cenozoic; Cores; Expedition 356; IODP Site U1459; Indian Ocean; Marine sediments; Neogene; Paleoclimatology; Paleoenvironment; Pliocene; Sediments; Tertiary
Record ID: 2017051569
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data supplied by, and/or abstract, Copyright, American Geophysical Union, Washington, DC, United States

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