The mid-Brunhes transition in ODP Sites 1089 and 1090 (subantarctic South Atlantic)

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doi: 10.1029/137GM09
Author(s): Hodell, David A.; Kanfoush, Sharon L.; Venz, Kathryn A.; Charles, Christopher D.; Sierro, Francisco J.
Author Affiliation(s): Primary:
University of Florida, Department of Geological Sciences, Gainesville, FL, United States
U. S. Geological Survey, United States
Lamont-Doherty Earth Observatory, United States
Scripps Institution of Oceanography, United States
Universidad de Salamanca, Spain
Volume Title: Earth's climate and orbital eccentricity; the marine isotope stage 11 question
Volume Author(s): Droxler, André W., editor; Poore, Richard Z.; Burckle, Lloyd H.
Source: Geophysical Monograph, Vol.137, p.113-129; American Geophysical Union, 1999 fall meeting; workshop on Marine isotope stage 11; an extreme interglacial?, San Fransisco, CA, Dec. 13-17, 1999, edited by André W. Droxler, Richard Z. Poore and Lloyd H. Burckle. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0065-8448. ISBN: 978-1-118-66849-8 CODEN: GPMGAD
Note: In English. 56 refs.; illus., incl. sketch map
Summary: We studied cores from ODP sites 1089 and 1090 in the subantarctic South Atlantic to reconstruct paleoceanographic changes during the mid-Brunhes in the context of climate evolution of the Pleistocene. The "mid-Brunhes event" is marked by an abrupt shift toward lower δ18O values during interglacial stages beginning with MIS 11, consistent with Jansen et al. [1986] who first proposed a mid-Brunhes transition to more humid, interglacial conditions in the southern hemisphere. In addition, we identified the "mid-Brunhes dissolution cycle" as part of a long-period oscillation that is expressed in dissolution indices and planktic δ13C, which reach maximum values during interglacial stages 13 and 11. Taking advantage of the high sedimentation rates at site 1089 (15 cm/kyr), we enumerate the sequence of events that occurred during Termination V and MIS 11 and speculate about their cause(s). A comparison between site 1089 and the Vostok ice core suggests that peak conditions of stage 11 are accurately captured in the ice core record, and that temperatures in the high-latitude southern hemisphere and global pCO2 levels during stage 11 were similar to the Holocene. Furthermore, a remarkable correlation between Vostok pCO2 and % foraminiferal fragmentation at site 1089 suggests a strong coupling of the marine carbonate system and atmospheric pCO2 during the mid-Brunhes. Although stage 11 and the Holocene share some similarities (e.g., orbital configuration, pCO2 etc.), caution is advised in using stage 11 as an analog for the Holocene because the maximum in dissolution and δ13C during the mid-Brunhes indicate that the marine carbonate-carbon cycle was fundamentally different than today.
Year of Publication: 2003
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Agulhas Ridge; Atlantic Ocean; Brunhes Chron; Cape Basin; Carbon; Carbon cycle; Carbonates; Cenozoic; Climate change; Geochemical cycle; Glacial environment; Interglacial environment; Isotope ratios; Isotopes; Leg 177; Marine sediments; O-18/O-16; ODP Site 1089; ODP Site 1090; Ocean Drilling Program; Oxygen; Paleo-oceanography; Paleoclimatology; Quaternary; Reconstruction; Sediments; South Atlantic; Stable isotopes; Subantarctic regions; Upper Quaternary
Coordinates: S405611 S405611 E0095338 E0095338
S425449 S425449 E0085359 E0085359
Record ID: 2004001346
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