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Project Progress

Onstott and McGown collected ground water from boreholes intersection fractures at depths of 890 and 1100 meters below the surface at the Lupin gold mine, Nunavat Territories March 2005 using 0.2 μm borosilicate filters and 0.2 μm hollow-fiber filters and running the borehole water through these filters for 2-3 days. This technique resulted in significantly higher recovery of biomass than was the case using membrane filters during sampling the previous year. A replicate set of borehole samples was collected in October 2005 by Pratt and Ruskinemmi using 0.2 μm borosilicate and hollow-fiber filters. Geochemical characterization of the two sets of water samples show only minimal changes in cation and anion compositions and in sulfur isotopic compositions of dissolved sulfate during the six months between replicate sampling. Out of six boreholes sampled, three yielded sufficient DNA for 16S rDNA phylogenetic characterization. The microbial community structure is dominated by sulfate reducing and sulfur oxidizing bacteria with a close resemblance to unnamed Arctic marine bacteria. This finding suggests introduction of microbes during recharge of fractures zones by marine water at previous times of higher sea level or crustal subsidence.

Onstott and Pratt received supplemental funding from the NAI to support drilling and acquisition of rock cores from deep permafrost situated in Archean metavolcanic rock strata in the Canadian Artic. In order to make the coring affordable, the scientific drilling campaign will piggyback on commercial exploration drilling of a copper-zinc sulfide deposit located at High Lake, Nunavut Territory. Aseptic techniques will be utilized in the acquisition of cores destined for microbial analyses. The core intervals will straddle the permafrost/subpermafrost brine boundary at 400 meters depths in order to examine changes in microbial communities, microbial activity, gas compositions and isotopic signatures across that interface. Drilling is targeted on a fracture zone based on surface geological mapping. If substantial amounts of fracture fluids are acquired then the borehole will be completed and sealed in a manner allowing us to return to this site in the future for multi-year monitoring of subpermafrost saline water. The team assembled to participate in the drilling expedition and analyses of core samples includes scientists from IPTAI, Michigan State University, University of Waterloo in Canada, the Finnish Geological Survey, Tufts University, Univ. of Colorado and the Jet Propulsion Laboratory. University of Waterloo and the Finnish Geological Survey are contributing funds toward the drilling and borehole completion.

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