论文部分内容阅读
中国东海舟山群岛的潮间带存在一处距今5600年左右的古木堆积层.对采自该潮间带的新鲜基岩样品、海岸风化壳剖面、海岸带渗滤水系统、埋藏古木渗滤水、潮间带沉积物、潮间带海水、岛上淡水和埋藏古木以及埋藏古木形成的泥炭质等潮间带环境介质进行元素地球化学分析,对海岸带渗滤水系统中的细菌成因铁氧化物和潮间带沉积物进行了详细的透射电子显微镜-选区电子衍射分析,并对埋藏古木形成的泥炭质和潮间带海滩泥的无机硫组成及其硫同位素组成进行了测定.结果显示,该潮间带环境介质出现了不同程度的Fe,Mn,S(SO42?)富集,是埋藏古木腐烂发酵对潮间带的Fe-S生物地球化学循环产生影响的结果.透射电子显微镜-选区电子衍射分析结果不仅证实铁细菌和硫酸盐还原菌在该潮间带环境中的大量存在、参与了Fe-S循环过程,而且诱导了胞外成矿作用.潮间带海滩泥中高的铬还原性硫(FeS2)含量和低的特征δ34S值(?2.9‰)不仅可能指示了潮间带沉积物中大量硫酸盐还原菌的存在,而且可能显示其中的铁硫矿物是在高的硫酸盐还原速率条件下形成的.本研究对于深刻认识潮间带、河口和近海岸带等高有机质累积速率和高硫酸盐还原速率条件下Fe-S生物地球化学循环和生物成矿特征具有重要的意义.
In the intertidal zone of the East China Sea, Zhoushan Archipelago, there exists an ancient layer of ancient wood dating from about 5600 years ago.For the samples of fresh bedrock collected from the intertidal zone, the coast weathering crust profile, coastal zone percolation system, Elemental geochemical analysis of water, intertidal sediments, intertidal seawater, freshwater on the island and buried ancient wood, and peat texture of buried ancient wood, Oxide and intertidal sediment were analyzed in detail by transmission electron microscopy-selected area electron diffraction and the inorganic sulfur composition and sulfur isotopic composition of the peat and intertidal beach mud formed by the buried ancient wood were measured. The results showed that , And the enrichment of Fe, Mn, S (SO42?) With different degrees of environmental media in the intertidal zone is the result of the influence of buried ancient wood decay fermentation on the Fe-S biogeochemical cycle in the intertidal zone.Transmission electron microscopy- The results of the selected area electron diffraction analysis not only confirmed the existence of a large number of iron bacteria and sulfate-reducing bacteria in the intertidal zone, but also participated in the Fe-S cycle and induced extracellular mineralization. The high chromium reductive sulfur (FeS2) content and low characteristic δ34S values (2.9 2.9 ‰) in beach mud may not only indicate the presence of a large number of sulfate-reducing bacteria in intertidal sediments, but may also indicate that the iron-sulfur minerals are Formed under high sulfate reduction rate.This study is of great significance for understanding the relationship between Fe-S biogeochemical cycles and biogenic mineralization under the condition of high accumulation rates and high sulfate reduction rates of intertidal zone, estuary and offshore zone, Features have important implications.