CGRG Bibliography of Canadian Geomorphology
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Author : Andersen, DT.; Pollard, W.H.; Vali, H.; Blank, C.; Omelon, C.R.; and McKay, C.P.
Date : 1999.
Title : Perennial springs in the Canadian High Arctic: Analogs of ancient Martian hydrothermal systems
Publication : Annual Meeting of the Geological Society of America, Denver, Colorado. October 27-30, 1999
Issue :
Page(s) :
Abstract
Biomineralization under low temperature hydrothermal conditions may have occurred on early Mars. Biominerals (biomarkers) in ancient hydrothermal sites may record past biological activity. Perennial springs located on western Axel Heiberg Island in the Canadian High Arctic may provide a unique analog to the early Martian hydrothermal environment. The springs occur in a region with a mean annual air temperature of -17°C and with thick, continuous permafrost reaching depths of 600 meters. Spring flow rates and discharge temperatures are constant throughout the year and biofilms and mineral precipitates occur in association with the emergent brine (~3x seawater). Low levels of dissolved tritium (< 0.2 T.U.) and elevated helium levels (~500x atmospheric) within the emergent groundwater provide evidence of a deep, subsurface water source. SEM and petrographic analysis of the travertine (calcite) deposits show them to consist of light (sparite) laminae (150-200 microns thick) interrupted by thin, dark (micrite) layers. Higher concentrations of Fe, S, and C in the dark layers suggest a fluid-rock interaction that is associated with microbial activity leading to the biogenic formation of Fe-bearing minerals. SEM observations of fresh samples show the presence of microbial populations attached to the mineral surfaces. Microorganisms collected on filters placed in the spring water are identified by molecular phylogenetics; these include sulfur/sulfide oxidizers, sulfate reducers and iron reducers. Insight gained from this study may help guide site selection for future missions to Mars.
Bibliography of Canadian Geomorphology