Boulder, Colo., USA This posting: Orange-like rocks in Utah with iron-oxide rinds and fossilized bacteria inside that are believed to have eaten the interior rock material, plus noted similarities to "bacterial meal" ingredients and rock types on Mars; fine-tuning the prediction of volcanic hazards and warning systems for both high population zones and at Tristan da Cunha, home to the most remote population on Earth; news from SAFOD; and discovery in Germany of the world's oldest known mosses.
Biosignatures link microorganisms to iron mineralization in a paleoaquifer
Karrie A. Weber et al., School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA. Posted online 15 June 2012; doi: 10.1130/G33062.1.
Iron oxide rocks in an ancient aquifer give scientists clues about where to look for past life on Mars and other planets, including Earth. Scientists at the University of Nebraska-Lincoln and University of Western Australia have been studying rocks in Utah that resemble an orange with an iron cemented rind and an interior that consists of glued sand. These rocks formed millions of years ago in an ancient aquifer. Using microscopic methods, Karrie Weber and colleagues found tiny fossilized bacteria inside of these rocks, along with evidence corroborating that the bacteria were once alive inside the rock. Weber and colleagues think that these bacteria "ate" the iron in the rock to form the iron oxide mineral-rich rind. All of the ingredients for a bacterial meal exist on Mars and other areas on Earth. This has led the Weber and colleagues to theorize that similar iron-rich rocks could have been formed by bacteria and could still be forming today. The scientists are continuing to study how bacteria form rocks below Earth's surface so to better understand the conditions that support life and the signatures that life leaves behind. This research is supported by the University of Nebraska Research Office and Nebra
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Geological Society of America