Challenges for Coring Deep Permafrost on Earth and Mars

This is the published version. Final publication is available from Mary Ann Liebert, Inc., publishers http://www.dx.doi.org/10.1089/ast.2007.0159.A scientific drilling expedition to the High Lake region of Nunavut, Canada, was recently completed with the goals of collecting samples and delineating gradients in salinity, gas composition, pH, pe, and microbial abundance in a 400 m thick permafrost zone and accessing the underlying pristine subpermafrost brine. With a triple-barrel wireline tool and the use of stringent quality assurance and quality control (QA/QC) protocols, 200 m of frozen, Archean, mafic volcanic rock was collected from the lower boundary that separates the permafrost layer and subpermafrost saline water. Hot water was used to remove cuttings and prevent the drill rods from freezing in place. No cryopegs were detected during penetration through the permafrost. Coring stopped at the 535 m depth, and the drill water was bailed from the hole while saline water replaced it. Within 24 hours, the borehole iced closed at 125 m depth due to vapor condensation from atmospheric moisture and, initially, warm water leaking through the casing, which blocked further access. Preliminary data suggest that the recovered cores contain viable anaerobic microorganisms that are not contaminants even though isotopic analyses of the saline borehole water suggests that it is a residue of the drilling brine used to remove the ice from the upper, older portion of the borehole. Any proposed coring mission to Mars that seeks to access subpermafrost brine will not only require borehole stability but also a means by which to generate substantial heating along the borehole string to prevent closure of the borehole from condensation of water vapor generated by drilling. Astrobiology 8, 623–638

Periglacial phenomena affecting nuclear waste disposal

Slow future changes in astronomic phenomena seem to make it likely that Finland nll suffer several cold periods during the next 100,000 years. The paper analyses the characteristics of the periglacial factors that are most likely to influence the long-term safety of high-level radioactive waste disposed of in bedrock. These factors and their influences have been divided into two categories, natural and human. It is concluded that the basically natural phenomena are theoretically better understood than the complicated phenomena caused by man. It is therefore important in future research into periglacial phenomena, as well as of the disposal problem, to emphasize not only the proper applications of the results of natural sciences, but especially the effects and control of mankind's own present and future activities

A geologically-based approach to map arsenic risk in crystalline aquifers : analysis of the Tampere region, Finland

The study illustrates the critical role of accurate geological structural mapping to delineate crystalline aquifer zones more prone to high health risk due to elevated dissolved As in drinking wells. The analysis revisits the results from more than 1200 groundwater samples collected over ten years from domestic wells across the Tampere region (Finland). It is demonstrated that the highest dissolved As concentrations in the region (up to 2230 \u3bcg/L) are exclusively found near major faults and deformation zones (FDZs) detected via geophysical and geological surveys, and that a clear correlation exists between dissolved concentrations and the distance from the FDZs (r). Almost all values exceeding the drinking water limit (10 \u3bcg/L) occur at r < 8 km, while concentrations above 100 \u3bcg/L occur at r < 4 km. Solid-phase As concentrations in bedrock show less dependency on FDZ than aqueous concentrations. This behavior is explained considering different mechanisms, which include enhanced sulfide oxidation and fracture connectivity, promoting preferential transport of dissolved As to FDZs and mixing of waters from different redox zones, mobilizing preferentially As(III) or As(V). Fe hydro-oxides may also precipitate/dissolve preferentially because of FDZs, while residence time may influence the contact time between water and As-bearing minerals. It is concluded that the accurate mapping of FDZs, and in general of structural geology, provides an important preliminary information to identify where localized, site-specific characterization of hydrogeology and geochemistry is more urgent to reduce As-related health risk from groundwater intake

Does underlying bedrock affect the geochemistry of drained peatlands?

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Management of risks posed by anthropogenic and natural arsenic at Pirkanmaa region, Finland

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