McLoughlin Nicola, Brasier Martin D, Wacey David, Green Owen R, Perry Randall S
Earth Sciences, Oxford University, Oxford, United Kingdom.
Astrobiology. 2007 Feb;7(1):10-26. doi: 10.1089/ast.2006.0122.
Micron-sized cavities created by the actions of rock-etching microorganisms known as euendoliths are explored as a biosignature for life on early Earth and perhaps Mars. Rock-dwelling organisms can tolerate extreme environmental stresses and are excellent candidates for the colonization of early Earth and planetary surfaces. Here, we give a brief overview of the fossil record of euendoliths in both sedimentary and volcanic rocks. We then review the current understanding of the controls upon the distribution of euendolithic microborings and use these to propose three lines of approach for testing their biogenicity: first, a geological setting that demonstrates a syngenetic origin for the euendolithic microborings; second, microboring morphologies and distributions that are suggestive of biogenic behavior and distinct from ambient inclusion trails; and third, elemental and isotopic evidence suggestive of biological processing. We use these criteria and the fossil record of terrestrial euendoliths to outline potential environments and techniques to search for endolithic microborings on Mars.
由被称为内石生生物的岩石蚀刻微生物作用形成的微米级空洞，被作为早期地球乃至火星上生命的生物特征进行探索。栖息于岩石中的生物能够耐受极端环境压力，是早期地球和行星表面殖民化的绝佳候选者。在此，我们简要概述沉积岩和火山岩中内石生生物的化石记录。然后，我们回顾当前对控制内石生微钻孔分布的理解，并利用这些理解提出三条检验其生物成因的方法：第一，一种能证明内石生微钻孔同生起源的地质环境；第二，暗示生物行为且与周围包裹体痕迹不同的微钻孔形态和分布；第三，暗示生物作用的元素和同位素证据。我们利用这些标准和陆地内石生生物的化石记录，概述在火星上寻找石内微钻孔的潜在环境和技术。
