Biological activities at the Archean submarine hydrothermal environments

太古代海底生物热液起源理论已成为一种流行的理论，但早期生物群的演化是在海底热液环境中进行的。在太古代地层中发现了丰富的海底热液沉积物，并存在着早期生物群的遗迹及其生态系统的化学化石的可能性。本项研究的主要目的是通过地质和地球化学方法来识别早期生物群及其生态系统的残留。在这项研究中，对两个地区进行了详细的地质调查：澳大利亚2.7 Ga的Abitibi绿岩带和3.2 Ga的Pilbara区块。与太古代海底热液活动和现代热液活动有关的其他样品也是本次研究的化学分析对象。本研究的主要发现有：富二氧化碳流体的特定热液蚀变作用和大洋地壳磷的活化作用;甲烷生物群的年龄比活性及其与岩浆活动的关系;热液反应使有机质中金属富集。在现代热水沉积物中发现了新的生态能量交换系统，并提出了与太古代生态系统的联系。这些成果已在国际和国内的一些期刊上发表，并在国际会议上作为特邀报告进行了报道。本文还提出了与现代岩浆活动有关的生物演化新理论。

Hydrothermal origin of life on the Archean seafloor is becoming a popular theory, besides the idea that the evolution of early biota took place at the submarine hydrothermal environments Abundant submarine hydrothermal sediments have been found in the Archean strata and there exists possibility that remnants of early biota and chemical fossils of their ecosystem were still preserved in these sediments. The main purpose of this study is to identify the remnants of early biota and their ecosystem based on the geological and geochemical ways. In this study, detailed geological surveys were conducted in two areas : the 2.7 Ga Abitibi Greenstone Belt and 3.2 Ga Pilbara Blocks in Australia. Other samples related to Archean submarine hydrothermal activities and modern hydrothermal activities were also subjects for the chemical analyses in this study. The followings are the notable findings from this study : specific hydrothermal alterations by carbon dioxide-rich fluids and mobilization of phosphorous from oceanic crust, age specific activity of methane-related biota and their association with magmatic activity and metal enrichments in organic matter by hydrothermal reaction. New ecological energy exchange system was also found in the modern hydrothermal sediments and its links to Archean ecosystem was also proposed. These achievements were already published in the several international and domestic journals, and also reported at international conferences as invited talks. New theory of biological evolution associated with the contemporary magmatic activity is also proposed from this study.