Glen Snyder

The McMurdo Dry Valleys Lakes of Antarctica provide an unusual opportunity to study aqueous systems in extremely cold and dry conditions. The composition of these lakes ranges from near freshwater, to extremely saline, with unusual enrichments in iodine. Similar enrichments have been observed in fracture fluids of the Fennoscandian and Canadian shields, and were interpreted by other researchers to contain cryogenically-enriched seawater which has been isolated for over 100 million years. If this is the case, essentially all of the ¹²⁹I present in the fluids was produced through spontaneous fission of naturally occurring uranium and thorium in the formations. Preliminary work, in collaboration with the Byrd Polar Research Center at Ohio State University, challenges this notion, and suggests that the McMurdo Dry Valleys Lakes represent open systems with similar ¹²⁹I and ³⁶Cl signatures. Our ongoing research will help determine whether or not the Dry Valleys Lakes provide a natural analogue to the development of fracture fluids in the northern hemisphere. The results of this study will be relevant to the planning of nuclear waste disposal sites in Europe and Canada, since waste repositories are slated for construction in both the Canadian and Fennoscandian shield.