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Mineralization of Bacteria in Terrestrial Basaltic Rocks: Comparison With Possible Biogenic Features in Martian Meteorite Allan Hills 84001The identification of biogenic features altered by diagenesis or mineralization is important in determining whether specific features in terrestrial rocks and in meteorites may have a biogenic origin. Unfortunately, few studies have addressed the formation of biogenic features in igneous rocks, which may be important to these phenomena, including the controversy over possible biogenic features in basaltic martian meteorite ALH84001. To explore the presence of biogenic features in igneous rocks, we examined microcosms growing in basaltic small-scale experimental growth chambers or microcosms. Microbial communities were harvested from aquifers of the Columbia River Basalt (CRB) group and grown in a microcosm containing unweathered basalt chips and groundwater (technique described in. These microcosms simulated natural growth conditions in the deep subsurface of the CRB, which should be a good terrestrial analog for any putative martian subsurface ecosystem that may have once included ALH84001. Here we present new size measurements and photomicrographs comparing the putative martian fossils to biogenic material in the CRB microcosms. The range of size and shapes of the biogenic features on the CRB microcosm chips overlaps with and is similar to those on ALH84001 chips. Although this present work does not provide evidence for the biogenicity of ALH84001 features, we believe that, based on criteria of size, shape, and general morphology, a biogenic interpretation for the ALH84001 features remains plausible.
Document ID
Acquisition Source
Johnson Space Center
Document Type
Thomas-Keprta, K. L.
(Lockheed Martin Corp. Houston, TX United States)
McKay, D. S.
(NASA Johnson Space Center Houston, TX United States)
Wentworth, S. J.
(Lockheed Martin Corp. Houston, TX United States)
Stevens, T. O.
(Battelle Pacific Northwest Labs. Richland, WA United States)
Taunton, A. E.
(Arkansas Univ. Fayetteville, AR United States)
Allen, C. C.
(Lockheed Martin Corp. Houston, TX United States)
Gibson, E. K., Jr.
(NASA Johnson Space Center Houston, TX United States)
Romanek, C. S.
(Savannah River Ecology Lab. Aiken, SC United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1998
Publication Information
Publication: Workshop on the Issue Martian Meteorites: Where do we Stand and Where are we Going?
Subject Category
Life Sciences (General)
Distribution Limits
Work of the US Gov. Public Use Permitted.

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