【作者】 张静；

【导师】 王成善；

【作者基本信息】 中国地质大学（北京） ， 古生物学与地层学， 2008， 硕士

【摘要】 在地质历史中,白垩纪被认为是温室气候的典型范例,发生了众多重大地质事件,其中黑色页岩和大洋红层为认识地球历史时期碳循环发生的重大变化提供了窗口。松辽盆地是我国大型白垩纪陆相含油气盆地,发育有完整的白垩纪陆相沉积纪录。白垩纪大陆科学钻探位于松辽盆地中央坳陷区,对整个白垩纪进行连续取芯。本文运用分子微生物学技术,对白垩纪大陆科学钻探工程中,在黑红转变界限附近采集的地质微生物样品进行分析,对其微生物群落组成、新陈代谢机制以及对周围环境的影响进行讨论,从分子生物学和地质学相结合的角度,讨论白垩纪松辽盆地黑红转变的过程,以及环境响应。主要实验方法包括:X射线荧光衍射;PLFA磷脂酸分析;16S rRNA基因分析技术和基因序列分析。根据研究目的,选取了两个岩芯样品B2-03和B2-05。B2-03取于1117m灰黑色泥岩,B2-05位于1215m暗红色泥岩,两样品中的生物量相当约为2×10~7cells/g。通过PCR(聚合酶链式反应)扩增得到细菌的16S rRNA,但缺失了古菌的16S rRNA。基因序列多样性分析发现,细菌的序列大多数属于低G+C%的G+菌和变形菌,嗜盐碱菌。在灰黑色样品B2-03中扩增得到的DNA序列较接近于水生金属硫酸盐还原菌,表示一种缺氧的还原环境;而红色样品B2-05中扩增得到的DNA序列更接近于水生金属氧化菌,指示一种富氧的氧化环境。通过X射线荧光衍射分析,在灰黑色样品B2-03中检测到了黄铁矿,指示还原环境,而红色样品B2-05在中测得了方沸石,指示氧化环境。通过岩相分析,说明灰黑色样品B2-03指示一种半深湖-深湖的还原环境,而红色样品B2-05指示一种深湖氧化环境。本文首次将分子微生物学技术运用到白垩纪陆相沉积的研究中,总结了一套行之有效的地质微生物学实验方法,并且取得的研究结果和白垩纪海相记录中的研究结果很相似,通过测量不同岩相岩芯样品中的生物量,对岩芯中保存的DNA进行16S rRNA基因多样性分析,发现不同岩相的岩芯样品中所含16S rRNA基因序列也不同,而且很好的对应了他们所在的地层的沉积环境,是很好的分子化石。更多还原

【Abstract】 In the geological history, Cretaceous is regarded as the exemplar of Greenhouse climate, punctuated by dramatic events such as the mid-Cretaceous ocean anoxic events (OAEs) and the Cretaceous Oceanic Red Beds are thought to provide a clue for researching the carbon recycle during the geological history. Songliao Basin is the largest oil and gas producing basin in China., with the most integrated and continuous Cretaceous terrestrial strata and geological records in the world. Cretaceous Continental Scientific Drilling situates in the northern central of Songliao Basin and aimed to obtain the complete cores of Cretaceous.This thesis uses molecular microbiological method to analyze the black and red mudstones sampling from the Cretaceous continental scientific drilling, and discusses the causes and the influences to the environment from the biological and geological aspects.The main experimental means contain X-ray Diffraction analysis, phospholipid fatty acid analysis, 16S rRNA gene analysis and gene sequences diversity analysis. According to the object, two samples, B2-03 (dark black, 1117 m depth) and B2-05 (red, 1215 m depth) were selected for microbial analyses. The PLFA-determined biomass is similar between the two samples, i.e.,～2 x 10~7 cells/g. Polymerase chain reaction (PCR) was able to successfully amplify bacterial 16S rRNA gene, but failed to amplify any archaeal 16S rRNA gene. Bacterial clone sequences mostly belong to low G + C Gram positives and Proteobacteria. Based on relatedness of clone sequences to close relatives and to other clone sequences from known environmental conditions, the bacterial community composition in both samples appeared to be dominated with halophilic, and alkaliphilic microorganisms. In the black sample (supposedly more reducing), clone sequences were mostly related to aquatic metal and sulfate (sulfur) reducing bacteria, whereas in the red sample (supposedly more oxidizing), clone sequences were related to aquatic sulfite and sulfur oxidizing bacteria. By XRD analyzing, there is pyrite in the black sample, which is formed in more reducing environment, whereas analcime exists in the red sample which is formed in more oxidizing environment.This is the first time using molecular microbiological methods to the systematic study of cretaceous terrestrial sedimental records. This research founds a feasible geomicrobiological methods and obtains a similar result with cretaceous marine sedimental records. And these data are encouraging and appear to suggest that microbial record (fossil DNA and biomarker) may be used to reflect paleo-environmental conditions.更多还原