Greenland

Tracing Glacial Meltwater Sources

Although noble gas studies have been carried out extensively in ice-free regions, studies of noble gases in glacial environments remain particularly scarce. High latitude regions such as Greenland are extremely sensitive to and are significant drivers of climate change due to the enormous water masses they store. Understanding climate shifts in the Greenland margins is critical as these areas may be particularly sensitive to global climate forcing. The Greenland Ice Sheet (GrIS) has been extensively studied to estimate its ice melting and acceleration rates, as well as its contributions to sea level rise. However, many questions remain to be answered pertaining to the dynamics and seasonality of the ice sheet, sources and composition of the meltwater, as well as temperature changes in Greenland and their driving mechanisms.

This noble gas pilot study of GrIS meltwater is meant to explore the information noble gases can provide in glacial environments with respect to glacial meltwater sources, relative source contributions, water residence times, and locations where this glacial meltwater originates within the ice sheet. Ultimately, we seek to improve our understanding of the dynamics of these massive ice sheets, critical for the major role they play in climate change. This is possible due to the conservative nature of noble gases and temperature dependency of their concentrations in equilibrated air saturated water (ASW), allowing for calculation of NGTs and, under certain assumptions, estimation of the altitude at which glacial meltwater originated. In addition, crustally produced isotopes such as 4He accumulate in water over time, allowing for a first order estimation of water residence times.

Publications

Niu Y., Castro M.C, Aciego S.M.,  Hall C.M..,  Emily I. S., Arendt C. and Sarah B. Das (2015), Noble Gas Signatures in Greenland – Tracing Glacial Meltwater Sources, in press, Geophys. Res. Lett., 42, doi:10.1002/2015GL065778.

Niu Y., Castro M.C., Hall C.M.., Aciego S.M., Emily I. S. and Arendt C., Noble Gas Signatures in Greenland – Tracing Glacial Meltwater Sources, AGU, Fall Meeting; 2014 Dec 15-19.

Photos above are from Dr. Aciego's research group field trip to Greenland in July and
August 2013.

This project is being carried out in collaboration with Dr. Sarah Aciego's Group at UM and with Dr. Sarah Das at Woods Hole Oceanographic Institution. It is being funded by the University of Michigan, the Packard Foundation (awarded to Dr. Aciego), and the Department of Earth Sciences Turner fellowship at the University of Michigan awarded to E. I. Stevenson.

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M. Clara Castro,
Jan 8, 2017, 6:20 AM