Surface ocean response to the mid-Pleistocene revolution and effects on the carbon cycle; a biomarker perspective

Author(s): McClymont, Erin Louise; Rosell-Melé, Antoni; Lloyd, Jerry M.
Author Affiliation(s): Primary:
University of Durham, Department of Geography, Durham, United Kingdom
Other:
Autonomous University of Barcelona, Spain
Volume Title: XVI INQUA congress; Shaping the Earth; a Quaternary perspective
Source: International Union for Quaternary Research [Congress of the International Union for Quaternary Research, Vol.16, p.189; XVI INQUA congress; Shaping the Earth; a Quaternary perspective, Reno, NV, July 23-30, 2003. Publisher:], International
Note: In English
Summary: During the Mid-Pleistocene, c.900 - 600 ka BP, the global climate system underwent a number of significant changes, most clearly represented by the emergence and subsequent dominance of glacial-interglacial oscillations at the 100-kyr frequency. Ice sheet dynamics, ocean circulation changes, and the carbon cycle have all been cited as potential key components in both the regulation and development of the 100-kyr cycles, but there are a limited number of reconstructions of surface ocean circulation patterns and carbon cycle components during this period. Here, we present results from marine sediment cores located in the Atlantic and equatorial Pacific Oceans, from the time interval 1500 - 500 ka BP. Biomarker reconstructions of sea-surface temperatures and carbon inputs to the ocean floor have been generated at a resolution of c.5-kyr. We compare records from the mid-high latitudes of the northern (ODP Site 983, 60°N) and southern Atlantic (ODP Site 1087, 31°S), to tropical records from the east (ODP Site 849, 110°W) and west equatorial Pacific (ODP Site 806, 159°E). The results indicate that significant synchronous changes in surface ocean circulation took place at all sites during the Middle Pleistocene, accompanied by enhanced carbon inputs to the ocean floor, prior to many previously published records of Mid-Pleistocene climate changes. Between c.1180 - 900 ka BP, surface ocean cooling is evident at all sites, accompanied by equatorward movements of the polar fronts and a possible upwelling increase within the Benguela system. This cooling phase is accompanied by enhanced inputs of marine carbon to the ocean floor, suggesting that the strength of the biological pump increased during this time. The surface ocean cooling culminates in a pronounced episode of SST fall at all sites, centred at c.900 ka BP, after which the polar fronts retreat poleward. A second phase of enhanced carbon input begins at this time, its termination marked by the onset of the dominant 100-kyr cycles in the ice volume records. These results highlight the potential significance of both surface ocean circulation and the carbon cycle in the development of the MPR.
Year of Publication: 2003
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 24 Surficial Geology, Quaternary Geology; Atlantic Ocean; Biomarkers; Carbon; Carbon cycle; Cenozoic; Geochemical cycle; Leg 130; Leg 138; Leg 162; Leg 175; Marine environment; Middle Pleistocene; ODP Site 1087; ODP Site 806; ODP Site 849; ODP Site 983; Ocean Drilling Program; Ocean circulation; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Pleistocene; Quaternary; Reconstruction; Sea-surface temperature; Upwelling
Coordinates: S312754 S312754 E0151839 E0151839
N602412 N602412 W0233826 W0233826
N001058 N001100 W1103110 W1103111
N001906 N001907 E1592142 E1592140
Record ID: 2004010804
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Desert Research Institute, Reno, NV, United States