Antarctica

Developing a New Noble Gas Paleoclimate Proxy

For over four decades noble gases (Ne, Ar, Kr,Xe) in groundwater systems have been used as indicators of past climate in ice-free regions through estimation of noble gas temperatures (NGTs). High latitude regions such as Antarctica are extremely sensitive to and are significant drivers of climate change due to the enormous water masses they store. Understanding past climate shifts in the Antarctica margins is even more critical as these areas maybe particularly sensitive to global climate forcing. East Antarctica and the McMurdo Dry Valleys area are of particular interest as this region is likely influenced by the North Atlantic Deep Water circulation. However, reliable millennial-scale continental records of climate in this area have been provided mostly by the Taylor Dome ice core. Additional independent paleoclimate proxies and further chronology controls are needed in this region to clarify the evolution of regional and global climate change. Traditional NGTs, however, cannot be derived in ice-covered regions where water is not in contact with the atmosphere.

One of the goals of this project is to take advantage of some of the noble gas properties in ice covered lakes at the ice/water interface to develop a new paleoclimate proxy with the potential to be routinely used in both polar and Alpine Glacial regions. It will take advantage of the differential partition between noble gases at the ice/water interface where the smaller atoms of He and, to some extent Ne, are more favorably incorporated in ice as opposed to Ar, Kr, and Xe which concentrate in the residual liquid water. Because the Taylor Valley lakes, McMurdo Dry Valleys, depend almost entirely upon stream meltwater supplied by nearby glaciers in addition to advances and retreats of the Ross Ice Shelf, their evolution is intimately connected to the dynamics of these ice masses which, in turn, are dictated by climate change. The perennial ice covers of these lakes form at the water/ice interface and sublimate at the top rendering these lakes ideal to test and develop this new proxy, which is based on estimation of ice rate formations based mostly on Kr and Xe concentration profiles. These are expected to record the long-term lake history and thus, climate evolution. This project involves collection of noble gas samples in ice covered lakes, in particular, Lakes Bonney, Fryxell and Hoare in the McMurdo Dry Valleys.



McMurdo Dry Valleys, McMurdo station and airport, Lakes Bonney and Hoare, Taylor Glacier. Hilary Dugan
and Kyle Cronin getting ready to sample brines for noble gas analyzis from Lake Hoare, January 2013.

This work is being carried out in collaboration with our colleagues Drs. Fabien Kenig at the University of Illinois at Chicago and Peter Doran at Louisiana State University. It is being funded by by the NSF Antarctica Sciences Section (ANT #1245580), Polar Programs (POLAR).

Publications

Warrier R.B.,  Castro M.C., Hall C.M., Doran P.T., Kenig F., (2014) Placing new constrains on the evolution of Lake Bonney, Antarctica through a noble gas study, Applied Geochemistry, DOI:10.1016/j.apgeochem.2015.02.013.

Warrier, R. B., Castro M. C., Hall., C. M., Kenig, F., Doran, P. T. (2013), Reconstructing the Paleo-Limnologic Evolution of Lake Bonney, Antarctica using Dissolved Noble Gases, Abstract H13I-1495 presented at 2013 Fall Meeting, AGU, San Francisco, Calif., 9-13 Dec.

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M. Clara Castro,
May 11, 2017, 6:09 PM
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M. Clara Castro,
May 27, 2015, 2:27 PM