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A comparative study of endolithic microborings in basaltic lavas from a transitional subglacial - marine environment

Cousins, Claire R.; Smellie, John L.; Jones, Adrian P.; Crawford, Ian A.. 2009 A comparative study of endolithic microborings in basaltic lavas from a transitional subglacial - marine environment. International Journal of Astrobiology, 8. 37-49. 10.1017/S1473550408004369

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Abstract/Summary

Subglacially erupted Neogene basaltic hyaloclastites in lava-fed deltas in Antarctica were found to contain putative endolithic microborings preserved in fresh glass along hydrous alteration boundaries. The location and existence over the past 6 Ma of these lava deltas has exposed them to successive interglacials and subsequent percolation of the hyaloclastite with marine water. A statistical study of the hyaloclastites has found that endolithic microborings are distinctly more abundant within samples that show evidence for marine alteration, compared with those that have remained in a strictly freshwater (glacial) environment. Additionally, correlation between elevation and the abundance of microborings shows endolithic activity to be more prolific within lower elevation samples, where the hyaloclastites were influenced by marine fluids. Our study strongly suggests that endolithic microborings form more readily in marine-influenced, rather than freshwater environments. Indeed, marine fluids may be a necessary precondition for the microbial activity responsible. Thus, we suggest that the chemistry and origin of alteration fluids are controlling factors on the formation of endolithic microborings in basaltic glass. The study also contributes to the understanding of how endolithic microborings could be used as a biosignature on Mars, where basaltic lavas and aqueous alteration are known to have existed in the past.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1017/S1473550408004369
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > Greenhouse to Icehouse. Evolution of the Antarctic Cryosphere and Palaeoenvironment
ISSN: 1473-5504
Additional Keywords: Antarctica, bioalteration, endolithic, freshwater, glaciovolcanism, hyaloclastite, Mars
Date made live: 01 Jun 2012 11:17
URI: http://nora.nerc.ac.uk/id/eprint/18254

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