Biogeochemical and Environmental Influences on the Composition of Late Archean Kerogens and Extracts

晚太古代(约2.7Ga)普遍存在13个贫碳干酪根，表明微生物甲烷循环是全球碳循环的主导过程。此外，目前可用的分子和同位素观察表明，存在好氧生物，可能是由各种沉积系统中的有氧微环境支持的。我们建议对西澳大利亚皮尔巴拉克拉通的Tumbiana组和Jeerinah组的岩心和露头样品以及相当单位的晚太古代有机质记录的沉积环境和生物地球化学特征之间的关系进行评估。我们的方法将沉积学和地层学观察与分子和干酪根同位素和化学性质的分析结合在一起。我们将提供将沉积环境条件与古代生命的分子和同位素特征联系起来的观察，并将尝试测试环境控制对早期地球上微生物生态系统和碳氧循环的重要性。

The late Archean (ca. 2.7 Ga) is characterized by widespread occurrence of 13 C-depleted kerogens which suggests microbial methane recycling was a dominant process in the global carbon cycle. In addition, available molecular and isotopic observations for this time suggest that aerobic organisms were present, possibly supported by oxygenated microenvironments within a variety of depositional systems. We propose to evaluate relationships among depositional environments and biogeocheniical signatures recorded in late Archean organic matter for core and outcrop samples of the Tumbiana and Jeerinah Formation and equivalent units in the Pilbara Craton in Western Australia. Our approach integrates sedimentological and stratigraphic observations with analyses of molecular and kerogen isotopic and chemical properties. We will provide observations linking depositional environmental conditions with molecular and isotopic signatures of ancient life and will attempt to test the importance of environmental control on microbial ecosystems and carbon and oxygen cycling on the early Earth.