海南岛三亚海滩岩中微生物引发的胶结作用研究

The beachrocks developed on the biological coasts of Sanya, Hainan Island will be studied by means of geomicrobiologic, carbonate sedimentologic and geochemical methods. Based on the field observation, thin-sectioning, Scanning Electron Microscope(SEM), Energy Dispersive X-ray Spectroscope(EDS) and geochemical analysis, the project will 1)study the sedimentary sequence and sedimentary characteristics of beachrocks; 2)recognize the microbial activities and microbial carbonates preserved in beachrocks; 3)describe the growth pattern and occurrence characteristics of microbial carbonates; 4)analyze the relationships between microbial activities and cementation in beachrocks; 5)evaluate the roles and significance of microbial activities and microbial-induced mineral precipitation in cementation and diagenesis of beachrocks; and 6)explore the formation conditions and environment information contained in microbial cementation. The project, from a new perspective, will expand the research scope on cementation of beachrocks, and enrich the deficiencies of studies on beachrocks in our country. The research results are of important scientific significance in the understanding of cementation mechanism induced by microbial activities and their roles in diagenesis of the beachrocks in coral reefal coast. Meanwhile, it also has academic and economic significances in understanding of the environmental effects of marine and terrestrial joint actions and the mechanisms of geological and biological joint actions in tropical coral-reefal coast, the marine deposition process and environment monitoring, climate evolution and marine environment changes, as well as the ecologic protection in biological coasts and sustainable utilization of marine resources.

运用地质微生物学、碳酸盐沉积学和地球化学方法对海南岛三亚生物海岸发育的海滩岩进行研究。采用野外观测、岩石薄片、扫描电镜和能谱及地球化学分析等手段，研究海滩岩的沉积序列和沉积特征，确认海滩岩中微生物活动和微生物碳酸盐沉积(包括微生物沉积和微生物钻孔)及微生物碳酸盐沉积的产出特征和发育方式，分析微生物活动与胶结物和胶结作用的关系，评价微生物活动及微生物引发的矿物沉淀在海滩岩胶结和成岩过程中的作用和重要性，探寻海滩岩中微生物相关的胶结物的形成条件和包含的环境信息。项目从一个新的切入点研究海滩岩的胶结作用，拓展海滩岩的研究内容，充实我国海滩岩研究不足。研究成果对探讨微生物在珊瑚礁海岸海滩岩的胶结作用机理及在碳酸盐岩成岩过程中的作用，对认识热带珊瑚礁生物海岸海陆相互作用的环境效应及地质和生物共作用机理，对海岸沉积过程和环境变化观测，对生物海岸生态保护和海洋生物资源可持续利用都具有理论和经济意义。

通过对海南岛三亚小东海、水尾岭珊瑚礁坪和海滩岩的调查和研究，参照对比海南岛东北部文昌青葛港、海南岛西部东方墩头镇、广西涠洲岛及湛江徐闻潮间带的现代/近代海滩岩和珊瑚礁坪，分析和确定微生物活动引发的胶结作用和微生物碳酸盐沉积物在珊瑚礁坪和海滩岩的形成过程中发挥重要作用。课题探讨微生物引发的碳酸盐沉积对环境和气候条件的响应，同时微生物成为影响现代海岸碳酸盐沉淀的标记；探讨礁坪微生物碳酸盐发育对珊瑚礁发育的响应机制。在海南岛三亚小东海的海滩岩中发现有微生物活动有关的碳酸盐胶结作用和微生物碳酸盐沉积物，从地质微生物学和碳酸盐沉积学两方面对微生物碳酸盐沉积的形成环境和发育模式进行了研究，探讨了海滩岩中不同胶结物的成因。研究证实1）我国南海的珊瑚礁坪和海滩岩沉积中有由微生物活动引发的碳酸盐沉积发育, 微生物作用过程在现代珊瑚礁系统形成中的重要性；2）支持海滩岩的胶结物部分是源于微生物成因的，进而肯定了微生物在碳酸盐沉积中所起的重要作用；3）为热带海域海岸带环境和海洋生态系统的保护提供科学依据。