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2008 Annual Science Report

Indiana University, Bloomington Reporting  |  JUL 2007 – JUN 2008

Challenges for Coring Deep Permafrost on Earth and Mars: Drilling Project at High Lake, Nunavut, Canada

Project Summary

Accessing liquid water environments and searching for life in the subsurface of Mars during future space missions will require drilling through hundreds of meters of permafrost and frozen rock. Many coring expeditions with the goal of acquiring uncontaminated cores for microbial studies have been performed on Earth, but none in deep permafrost, hard rock terranes. The goal of this project was to determine the requirements for obtaining permafrost core samples that are useful for microbial analyses and to acquire experience in coring through permafrost into the underlying liquid water, fractured rock system at High Lake, Nunavut, Canada.

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

Challenges for Coring Deep Permafrost on Earth and Mars: Drilling Project at High Lake, Nunavut, Canada

A scientific drilling expedition to the High Lake region of Nunavut, Canada, was completed in August of 2006 with the goal of collecting samples and delineating gradients in salinity, gas composition, pH, pe and microbial abundance in a 400 m thick permafrost zone, and to access the underlying pristine sub-permafrost brine. With a triple-barrel wire line tool and the use of stringent QA/QC protocols, 200 m of frozen, Archean, mafic volcanic rock was collected from the lower boundary that separates the permafrost layer and sub-permafrost 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. A paper describing these results has just been published in Astrobiology.
Complete pore water analyses of the permafrost rock has been combined with 35S microautoradiography to obtain a vertical profile of microbial sulfate reduction rates which reveals increasing rates with depth. These results were presented at the 2007 ASM in Toronto and at AbSciCon 2008.

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    Tullis Onstott Tullis Onstott
    Project Investigator
    Barry Freifeld
    Adam Johnson
    Susan Pfiffner Susan Pfiffner
    Lisa Pratt Lisa Pratt
    Corien Bakermans

    Objective 2.1
    Mars exploration

    Objective 5.1
    Environment-dependent, molecular evolution in microorganisms

    Objective 7.1
    Biosignatures to be sought in Solar System materials