造礁珊瑚是高分辨率古气候重建研究的重要载体，然而在埋藏过程中，珊瑚很容易发生成岩蚀变，所保存的气候环境信息被破坏。了解珊瑚蚀变过程中关键地球化学体系的变化机制，并对其进行定量化限定对准确解读蚀变珊瑚中的气候环境演变信息具有重要意义。本项目拟人工模拟自然环境下的珊瑚蚀变过程，同步分析珊瑚和反应水体中关键的同位素组成（δ13C-δ18O-Δ47、δ11B-δ44/40Ca-δ88Sr），定量评估其变化；同时对典型海域经受过蚀变的天然珊瑚样品进行同步分析，验证人工蚀变的结果。在此基础上，对取自南沙美济珊瑚礁钻孔“南科一井”岩芯进行相关的元素和同位素组成分析，解读美济礁形成和演化过程中所经历的气候环境演变或成岩蚀变信息。此项研究可以更好地限定成岩蚀变对珊瑚元素和同位素地球化学组成的影响，为了解南海岛礁形成演化对气候环境变化的响应，更好评估岛礁地质和生态环境在全球变化背景下的发展趋势提供重要科学依据

As one of most important archives for high-resolution paleoclimate studies, hermatypic corals are easily subjected to diagenetic alteration after deposition and buried, which affects the environmental signals recorded in their skeletons. To more precisely decipher the climatic and environmental information based on corals that have experienced post-diagenesis, it is crucial to understand the variation mechanism of the key geochemical compositions in coral skeletons during the diagenesis. Here we propose to experimentally simulate the coral diagenesis under different controlled conditions and quantitatively constrain the variations of some isotopic compositions (δ13C-δ18O-Δ47、δ11B-δ44/40Ca-δ88Sr) in coral carbonates and diagenetic fluids. These results will be verified by natural corals that have experienced natural diagenesis from typical areas. On these bases, we will be able to interpret the climatic and environmental information or diagenetic signals recorded by a drill core (namely “Nanke-1 Well) from Meiji Island of the Nasha Islands based on analyses of the elements and isotopic compositions. This study will help to better constrain the effect of diagenesis on the coral geochemical compositions that is of significance for understanding the response of formation and evolution of islands and reefs in the South China Sea to climate and environmental changes and for evaluating the trends of the development of reef geology and ecological environment in the context of global changes.