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Growth of synthetic stromatolites and wrinkle structures in the absence of microbes - implications for the early fossil record.
Geobiology ( IF 2.7 ) Pub Date : 2008-04-03 , DOI: 10.1111/j.1472-4669.2007.00141.x
N McLoughlin 1 , L A Wilson , M D Brasier
Affiliation  

Stromatolites and wrinkle structures are often taken to be an important indicator for early life. While both may be shaped by microbial mat growth, this can be open to doubt, so that the contribution of abiotic processes in their construction always needs to be established (Grotzinger & Knoll, 1999). We here report laboratory spray deposition experiments that can generate stromatolites and wrinkle structures in the absence of microbes. These minicolumnar and sometimes branched stromatolites are produced artificially by the aggregation of a synthetic colloid in a turbulent flow regime. They self-organize at the relatively low particle concentrations found in the outer parts of a spray beam. This contrasts with adjacent stratiform deposits that are produced by high rates of colloid deposition and relatively low sediment viscosities found in the centre of a spray beam. These stratiform laminae become subsequently wrinkled during hardening of the colloid. These results support numerical models that together suggest that physicochemical processes are capable of generating laminated sedimentary structures without the direct participation of biology. Geological environments where comparable abiogenic stromatolites and wrinkle structures may be found include: splash-zone silica sinters, desert varnish crusts and early Archean cherts formed from silica gel precursors.

中文翻译:

在没有微生物的情况下,合成叠层石的生长和皱纹结构-对早期化石记录的影响。

基质石和皱纹结构通常被认为是早期生命的重要指标。尽管两者都可能受微生物垫生长的影响,但这值得怀疑,因此,始终需要确定非生物过程在其构建中的作用(Grotzinger&Knoll,1999)。我们在这里报告了实验室喷雾沉积实验,可以在没有微生物的情况下产生叠层石和皱纹结构。这些微型柱状或有时分支的叠层石是在湍流状态下通过合成胶体的聚集而人工产生的。它们在喷雾束外部的相对较低的颗粒浓度下会自组织。这与相邻的层状沉积物形成对比,后者是由高胶体沉积速率和在喷雾束中心发现的相对较低的沉积物粘度产生的。这些层状薄层随后在胶体硬化期间起皱。这些结果支持数值模型,这些数值模型一起表明物理化学过程能够在没有生物学直接参与的情况下产生层状沉积结构。可以发现类似的生物成因叠层石和皱纹结构的地质环境包括:飞溅带二氧化硅烧结矿,沙漠清漆地壳和由硅胶前体形成的早期太古代Arch石。这些结果支持数值模型,这些数值模型一起表明物理化学过程能够在没有生物学直接参与的情况下产生层状沉积结构。可以发现类似的生物成因叠层石和皱纹结构的地质环境包括:飞溅带二氧化硅烧结矿,沙漠清漆地壳和由硅胶前体形成的早期太古代Arch石。这些结果支持数值模型,这些数值模型一起表明物理化学过程能够在没有生物学直接参与的情况下产生层状沉积结构。可以发现类似的生物成因叠层石和皱纹结构的地质环境包括:飞溅带二氧化硅烧结矿,沙漠清漆地壳和由硅胶前体形成的早期太古代Arch石。
更新日期:2019-11-01
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