© ICDP, the International Continental Scientific Drilling Program, 1996-2021

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The Coulman High Project?Drilling beneath the Ross Ice Shelf to understand Antarctic Ice Sheet sensitivity to climatic, tectonic, and environmental forcing in a high CO2 world

Antarctica, Ross Embayment, Coulman High

new full-proposal: ICDP-2014/02
for the funding-period starting 2014-01-15
by Richard Levy, Timothy Naish, David Harwood, Fabio Florindo, Andrea Catalina Gebhardt, Yusuke Suganuma, Robert McKay, Jae Il Lee, Steven M. Bohaty, Robert M. DeConto, Denise Kay Kulhanek, Timothy S. Paulsen, Frank R. Rack, Amelia Endicott Shevenell, Julia Smith Wellner, Douglas S. Wilson, Luigi Jovane
Abstract
The Coulman High Project (CHP) proposes to recover two, high-quality, continuous drill-cores by drilling into Paleogene to lowest Miocene strata beneath the Ross Ice Shelf on the Coulman High (77.46° S, 171.4° E) in the Ross Embayment, Antarctica. The overarching objective is to establish a history of Cenozoic climate, tectonic and glacial changes in an ice-proximal setting to determine the sensitivity of Antarctica’s ice sheets to a range of climatic and tectonic forcings. The sedimentary archives to be recovered in these two ~800-m drill holes will offer a window into the range of environments, ecosystems and tectonic events in the Ross Sea region as it stepped from the warm, high-CO2 Greenhouse world of the Eocene into the lower-CO2 and highly variable Icehouse climate of the Oligocene and early Miocene. Antarctica was the keystone in this global climate transition and hosted the growth of ice sheets that started major cryosphere influence on global systems. The sensitivity of the climate system to elevated levels of greenhouse gases, the strength of polar amplification, and the behavior of the AIS in a world warmer than today remain fundamental questions to be addressed by CHP’s integrated data-climate modeling studies. These seek to reduce the large uncertainties in predictions of future ice-sheet dynamics and sea level, in part by testing models with ancient scenarios under conditions warmer than today. To improve predictions of long-term future climate and sea level, it is imperative to obtain geological records of past polar climates and ice sheets from time intervals when atmospheric CO2 was two to four times higher than present levels. Modern observations and instrumental records provide details regarding current and short-term change, but high-fidelity climate records that span previous periods characterized by higher-than-present CO2 are only available from the Earth’s geological records. CHP drill sites are a high latitude end-member of a transect of sites through the SW Pacific to investigate mechanisms that drove amplification of polar temperature during the Paleogene. ANDRILL seeks to partner with ICDP in the pursuit of new knowledge to understand important and relevant questions about Earth's system interactions and climate dynamics. CHP provides an opportunity for synergistic collaboration between ICDP and ANDRILL, which will extend the influence of ICDP to the Antarctic continent. Opportunities for technical collaboration, pooling of knowledge, expertise and capability around drilling technology, data and core management, and education and outreach will be to the benefit of both programs.
Scientific Objectives
  • Coulman High Project’s overarching objective is to establish a history of Cenozoic climate, tectonic and glacial change in an ice-proximal setting in order to determine the response and sensitivity of Antarctica’s ice sheets to a range of climatic, environmental, and tectonic forcings. Results will provide insight into past cryosphere variability under elevated atmospheric CO2 levels, and help identify thresholds and equilibrium responses to a range of climate states. Coulman High Project sites are selected to:
  • 1) Examine important steps in Cenozoic climate evolution starting from conditions of Eocene greenhouse warmth, then investigate the causes of subsequent ice volume variations across Eocene - Oligocene and Oligocene - Miocene transitions, evaluating the role of atmospheric CO2 relative to other forcing factors;
  • 2) Address questions on ice sheet response to past climate change and tectonic evolution through the period from inception of large terrestrial ice sheets in West Antarctica to the onset of marine-based ice sheets across the Ross Sea continental shelf;
  • 3) Constrain the timing of rifting and subsidence of the West Antarctic Rift System, and its influence on West Antarctic ice sheet history, as this region transitioned from a predominantly terrestrial to submarine environment; and 4) Provide a high latitude [78°S] ice-proximal end-member of a transect through the SW Pacific (including IODP 318 [~65°S], ODP 1172 [~65°S], DSDP 277-279 [~60°S], New Zealand [~50 to 45°S], and pending IODP projects) to investigate mechanisms that drove amplification of polar temperature and forced ice sheet retreat under elevated atmospheric CO2 conditions during the Paleogene.
Keywords
Antarctica, Coulman high, Cryosphere, ICDP-2014/02, Paleoclimate, Paleogene, SEYMOUR, Tectonics
Location
Antarctica, Ross Embayment, Coulman High: -77.46, 171.4

© ICDP, the International Continental Scientific Drilling Program, 1996-2021

www.icdp-online.org