論文

査読有り
2012年4月

Evidence for life in the isotopic analysis of surface sulphates in the Haughton impact structure, and potential application on Mars

INTERNATIONAL JOURNAL OF ASTROBIOLOGY
  • John Parnell
  • ,
  • Adrian J. Boyce
  • ,
  • Gordon R. Osinski
  • ,
  • Matthew R. M. Izawa
  • ,
  • Neil Banerjee
  • ,
  • Roberta Flemming
  • ,
  • Pascal Lee

11
2
開始ページ
93
終了ページ
101
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1017/S1473550411000395
出版者・発行元
CAMBRIDGE UNIV PRESS

The analysis of sulphur isotopic compositions in three sets of surface sulphate samples from the soil zone in the Haughton impact structure shows that they are distinct. They include surface gypsum crusts remobilized from the pre-impact gypsum bedrock (mean delta S-34 + 31 parts per thousand), efflorescent copiapite and fibroferrite associated with hydrothermal marcasite (mean delta S-34 - 37 parts per thousand), and gypsum-iron oxide crusts representing weathering of pyritic crater-fill sediments (mean delta S-34 + 7 parts per thousand). Their different compositions reflect different histories of sulphur cycling. Two of the three sulphates have isotopically light (low delta S-34) compositions compared with the gypsum bedrock (mean delta S-34 + 31 parts per thousand), reflecting derivation by weathering of sulphides (three sets of pyrite/marcasite samples with mean delta S-34 of -41, -20 and -8 parts per thousand), which had in turn been precipitated by microbial sulphate reduction. Thus, even in the absence of the parent sulphides due to surface oxidation, evidence of life would be preserved. This indicates that on Mars, where surface oxidation may rule out sampling of sulphides during robotic exploration, but where sulphates are widespread, sulphur isotope analysis is a valuable tool that could be sensitive to any near-surface microbial activity. Other causes of sulphur isotopic fractionation on the surface of Mars are feasible, but any anomalous fractionation would indicate the desirability of further analysis.

リンク情報
DOI
https://doi.org/10.1017/S1473550411000395
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000300947100003&DestApp=WOS_CPL
ID情報
  • DOI : 10.1017/S1473550411000395
  • ISSN : 1473-5504
  • Web of Science ID : WOS:000300947100003

エクスポート
BibTeX RIS