Resolving apparent conflicts between oceanographic and Antarctic climate records and evidence for a decrease in pCO(2) during the Oligocene through early Miocene (34-16 Ma)

Publication Type  Journal Article
Year of Publication  2008
Authors  Pekar, S. F.; Christie-Blick, N.
Journal Title  Palaeogeography Palaeoclimatology Palaeoecology
Volume  260
Issue  1-2
Pages  41-49
Journal Date  Apr 7
ISBN Number  0031-0182
Accession Number  ISI:000255434800004
Key Words  oligocene; miocene; ice volume; sea level; antarctica; oxygen isotopes; global sea-level; victoria land basin; ice-sheet; ross sea; continental-margin; glaciation; sequences; chronology; boundary; calcite

An apparent mismatch between published oxygen isotopic data and other paleoclimate proxies for the span from 26-16 Ma is resolved by calibration against global sea-level estimates obtained from backstripping continental margin stratigraphy. Ice-volume estimates from calibrated oxygen isotope data compare favorably with stratigraphic and palynological data from Antarctica, and with estimates of atmospheric pCO(2) throughout the Oligocene to early Miocene (34-16 Ma). Isotopic evidence for an East Antarctic Ice Sheet (EAIS) as much as 30% larger than its present-day volume at glacial maxima during that span is consistent with seismic reflection and stratigraphic evidence for an ice sheet covering much of the Antarctic continental shelf at the same glacial maxima. Palynological data suggest long-term cooling during the Oligocene, with cold near-tundra environments developing along the coast at glacial minima no later than the late Oligocene. A possible mechanism for this long-term cooling is a decrease in atmospheric pCO(2) from the middle Eocene to Oligocene, reaching near pre-industrial levels by the latest Oligocene, and remaining at those depressed levels throughout the Miocene. Published by Elsevier B.V.


294VQTimes Cited:1Cited References Count:58

URL  <Go to ISI>://000255434800004
DOI  DOI 10.1016/j.palaeo.2007.08.019