Assessing the biogenicity and syngenicity of candidate bioalteration textures in pillow lavas of the～2.52 Ga Wutai greenstone terrane of China  

作　　者：McLOUGHLIN N FLIEGEL DJ FURNES H STAUDIGEL H SIMONETTI A ZHAO GuoChun ROBINSON P T 

机构地区：[1]Department of Earth Science and Center for Geobiology, AUegaten 41, Bergen N-5007, Norway [2]Scripps Institution of Oceanography, University of California, La Jolla, CA 92093-0225, USA [3]Department of Civil Engieering and Geological Sciences, University of Notre Dame, Indiana, IN46556, USA [4]Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China [5]Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 4J1, Canada

出　　处：《Chinese Science Bulletin》2010年第2期188-199,共12页

基　　金：supported by a Norwegian Research Council Project, National Natural Science Foundation of China (Grant No. 40730315);Hong Kong RGC GRF (Grant Nos. HKU7063/06P,7066/07P and 7057/08P)

摘　　要：住在 sub-seafloor 熔岩的微生物能够蚀刻暴烈的玻璃并且创造微米大小的隧道和坑。这些 bioalteration 踪迹的矿化作用保证这些质地熬过主人玻璃的变丑和转变到变形矿物质。如此的 bioalteration 质地的石块记录从在原处海洋的外壳在暴烈的玻璃以外远延长从 ophiolites 和前寒武纪的绿岩带包括元暴烈的玻璃。薄节从 N 的 Wutai 组从 2.52 Ga tholeiitic 枕头熔岩这里报导了的 petrographic 的调查。中国成立细丝状微质地。激光拉曼光谱学证实这些质地被 titanite 使矿物化。而且， Wutai 微质地在到从太古代的 greenschist 外形枕头熔岩的 bioalteration 质地的尺寸，形态学和分发是可比较的。在原处，诱导地由激光脱离多收集者 titanite 标明日期的 U-Pb 联合了团 spectrometry (LA-MC-ICP-MS ) 给 1.81 敢 ? 汢獥敳 ? 楷桴的年龄的血浆吗？Microorganisms that inhabit sub-seafloor lavas are capable of etching volcanic glass and creating micron-sized tunnels and pits. Mineralization of these bioalteration traces ensures that these textures survive deformation and transformation of the host glass to metamorphic minerals. The fossil record of such bioalteration textures extends far beyond volcanic glass from in-situ oceanic crust to include meta-volcanic glass from ophiolites and Precambrian greenstone belts. Investigation of petrographic thin section reported here from -2.52 Ga tholeiitic pillow lavas from the Wutai Group of N. China found filamentous micro-textures. Laser Raman spectroscopy confirmed that these textures are mineralized by titanite. Moreover, the Wutai micro-textures are comparable in size, morphology and distribution to bioalteration textures from Archean greenschist facies pillow lavas, ln-situ U-Pb dating of the titanite by laser ablation multi-collector inductively coupled plasma mass spectrometry （LA-MC-ICP-MS） gives an age of 1.81 ± 0.12 Ga （2σ, n=22, ^206pb/^238U weighted average）. This provides a minimum age for the mineralization of these candidate bioalteration textures and corresponds to a regional metamorphic event. This also represents a minimum age estimate for the timing of bioalteration and is compatible with the existence of a Late Archean-Proterozoic sub-seafloor biosphere.

关 键 词：枕状熔岩 候选人 绿岩带 纹理 中国 电感耦合等离子体质谱 五台山 地体 

分 类 号：Q913[天文地球—古生物学与地层学]