IODP 1011-Pre – Northeast Greenland Glaciated Margin

Abstract

The Greenland Ice Sheet is identified as a tipping point element within the Earth’s climate system, which under the current trend of CO2 emissions is at risk of becoming unstable, possibly leading to a complete meltdown. Its contribution to global sea-level rise during last centuries has been a prelude to the increasing ice sheet runoff exacerbated by polar amplification. Thus, understanding the long-term stability of the Greenland Ice Sheet is critical for anticipating future climate and sea-level scenarios. While coupling between the ice sheet, ocean and sea ice is readily observable today in Northeast Greenland, geological records of past conditions and ice sheet dynamics for illuminating long-term trends are lacking. Deep ocean records from the Nordic Seas have previously provided insights into the Cenozoic ice-ocean-tectonic evolution of the northern North Atlantic. There are, however, outstanding questions related to the past evolution and dynamics of the Greenland Ice Sheet, where the Northeast Greenland continental margin forms a missing piece of the puzzle. NorthGreen aims to cover this knowledge gap by drilling the prograded shelf margin of Northeast Greenland which is associated with major trough-mouth fans and contourite accumulations. The scientific objectives are: (1) Illuminate the timing and environmental conditions at the onset of glacial expansion; (2) understand the dynamics of the Greenland Ice Sheet during abrupt changes in atmospheric and oceanographic conditions; and (3) investigate the effects of regional tectonic and oceanographic changes on the polar cryospheric evolution. To accomplish these objectives, NorthGreen proposes to drill twelve sites (6 primary complemented by 6 alternate) along transects crossing the Northeast Greenland continental shelf and slope. The sites are located within the Norske Trough and on the glaciated bank areas immediately south of the trough. Norske Trough represents one of the main outlets of the Northeast Greenland ice stream, which currently drains 20% of the Greenland Ice Sheet. Thus, the targeted sedimentary sequences contain high-resolution information that is directly linked to the early evolution and variability of the Greenland Ice Sheet as well as the control factors of its dynamics (e.g., climate, oceanography and tectonics) and their interaction through time. The region is densely covered by seismic data and several shallow core sites exist, facilitating the identification of drilling targets and development of the experimental design.