Notice: This is an archived and unmaintained page. For current information, please browse

2008 Annual Science Report

Indiana University, Bloomington Reporting  |  JUL 2007 – JUN 2008

High Lake Gossan Deposit: An Arctic Analogue for Ancient Martian Surficial Processes?

Project Summary

The massive sulfide deposit at High Lake is covered by a ~1 meter thick layer of Fe oxides and sulfate minerals. The minerals have formed within the last 8,000 years in the active zone of the permafrost and as such the site provides a good analog to those terranes on Mars that contain similar mineral assemblages, e.g. Terra Meridiana, and may have formed under similar, acidic conditions. The minerals present in the High Lake gossan were characterized by XRD, SEM and Mössbauer.

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

High Lake Gossan deposit: An Arctic analogue for ancient Martian surficial processes?

Gossan samples collected during two expeditions to High Lake in Nunavut, Canada, were analyzed to determine their mineral components in order to define parameters for the geochemical environment in which they formed. The gossans represent a natural acid drainage site in an arctic environment that serves as an analogue to the conditions under which sulfate and Fe-oxide formed on Mars. Rock and soil samples were taken from three different outcrops and analyzed using XRD, SEM/EDS, and, in collaboration with R.V. Morris of Johnson Space Center, Mössbauer. Two main mineral assemblages were observed. The first assemblage, which was found primarily in samples from the first outcrop, contained chlorite, phosphate, Fe-oxide, talc and quartz. The second assemblage, which was found at the second and third outcrops, was primarily quartz, mica and jarosite. One sample (G41), which contained Fe-oxide, jarosite and the only observed appearance of gypsum, appears to be transitional between an Fe-oxide dominant assemblage to a jarosite dominant assemblage. Thermodynamic equilibrium with water from seasonal snow melt predicts that the gossan pore water should range from highly acidic and sulfate-rich (pH 0.5-3; SO4 > 3000mg/l) for the second mineral assemblage to mildly acidic, less sulfate-rich (pH 3-6; SO4 < 1000mg/l) for the first assemblage. The High Lake gossan differs from acid mine drainage sites located in temperate regions by its lack of diverse sulfate species and smaller crystal sizes. The smaller crystal size may reflect the slower reaction rates at colder temperatures and the seasonal water saturation. These initial results indicate that the High Lake gossan deposit does record mechanisms for which minerals like hematite, goethite, gypsum and jarosite, which are found on Mars, can form in an environment that involves seasonal water occurrence in a cold climate. A manuscript describing these results has been submitted to Planetary and Space Science.

{{ 1 }}

{{ 2 }}

    Tullis Onstott Tullis Onstott
    Project Investigator
    Dan McGown
    Doctoral Student

    Logan West
    Undergraduate Student

    Objective 2.1
    Mars exploration

    Objective 5.1
    Environment-dependent, molecular evolution in microorganisms

    Objective 5.2
    Co-evolution of microbial communities

    Objective 5.3
    Biochemical adaptation to extreme environments

    Objective 6.1
    Environmental changes and the cycling of elements by the biota, communities, and ecosystems

    Objective 7.1
    Biosignatures to be sought in Solar System materials