An Antarctic stratigraphic record of stepwise ice growth through the Eocene-Oligocene transition

Authors

Sandra Passchier, Montclair State UniversityFollow
Daniel J. Ciarletta, Montclair State UniversityFollow
Triantafilo E. Miriagos, Montclair State University
Peter K. Bijl, Utrecht UniversityFollow
Steven M. Bohaty, University of SouthamptonFollow

Document Type

Article

Publication Date

3-1-2017

Abstract

Earth’s current icehouse phase began ∼34 m.y. ago with the onset of major Antarctic glaciation at the Eocene-Oligocene transition. Changes in ocean circulation and a decline in atmospheric greenhouse gas levels were associated with stepwise cooling and ice growth at southern high latitudes. The Antarctic cryosphere plays a critical role in the ocean-atmosphere system, but its early evolution is still poorly known. With a near-field record from Prydz Bay, Antarctica, we demonstrate that Antarctic ice growth was stepwise and had an earlier onset than previously suggested. Prydz Bay lies downstream of a major East Antarctic Ice Sheet drainage system, and its sedimentary records uniquely constrain the timing of ice-sheet advance onto the continental shelf. We investigated a detrital record extracted from three Ocean Drilling Program drill holes within a new depositional and chronological framework spanning the late Eocene to early Oligocene (ca. 36–33 Ma). The chemical index of alteration (CIA) and the S index, calculated from the major-element geochemistry of bulk samples, yielded estimates of chemical weathering intensities and mean annual temperature on the East Antarctic continent. We document evidence for late Eocene mountain glaciation along with transient warm events at 35.8–34.8 Ma. From 34.4 Ma, associated with the Eocene-Oligocene transition precursor δ¹⁸O excursion, glaciers advanced into Prydz Bay, coincident with a decline in chemical weathering and temperature. We conclude that Antarctic continental ice growth commenced with the Eocene-Oligocene transition “precursor” glaciation, during a time of Subantarctic surface ocean cooling and a decline in atmospheric pCO₂. These results call for dynamic high-latitude feedbacks that are currently poorly represented in Earth system models and emphasize the need for additional near-field glacio-sedimentological, high-latitude sea-surface temperature and pCO₂ records across the Eocene-Oligocene transition.

Comments

The following article appeared in GSA Bulletin (ISSN: 0016-7606, ESSN: 1943-2674), and may be found at 10.1130/B31482.1. This article may be downloaded for personal use only. Any other use requires prior permission of the author and Geological Society of America

MSU Digital Commons Citation

Passchier, Sandra; Ciarletta, Daniel J.; Miriagos, Triantafilo E.; Bijl, Peter K.; and Bohaty, Steven M., "An Antarctic stratigraphic record of stepwise ice growth through the Eocene-Oligocene transition" (2017). Department of Earth and Environmental Studies Faculty Scholarship and Creative Works. 27.
https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/27

Published Citation

Sandra Passchier, Daniel J. Ciarletta, Triantafilo E. Miriagos, Peter K. Bijl, Steven M. Bohaty; An Antarctic stratigraphic record of stepwise ice growth through the Eocene-Oligocene transition. GSA Bulletin ; 129 (3-4): 318–330. doi: https://doi.org/10.1130/B31482.1