海南岛鹿回头水尾岭海滩岩中的微生物岩

THE DEVELOPING PATTERN FOR CRYPTIC INTERTIDAL MICROBIALITES IN BEACHROCK OF SHUIWEI RIDGE OF LUHUITOU PENINSULA

在海南岛的海滩岩中首次发现了微生物岩,这是一种发育在珊瑚(碎屑和砾块)骨骼孔穴中,少量在珊瑚碎块表面的微生物碳酸盐沉积,这些微生物碳酸盐沉积呈叠层或包壳状生长,可黏结细小的生物碎屑,具有独特的发育模式。微生物碳酸盐沉积在南海的发现支持海滩岩的胶结物部分是源于微生物成因的假设,进而肯定了微生物在碳酸盐沉积中所起的重要作用。结合海滩岩组分中微钻孔的发育特征和微生物岩发育模式的描述,在一定程度上填补了我国南方海滩岩中发育微生物碳酸盐沉积物的研究空白。

Microbialites with microcolumnar growth morphology occuring on the surfaces of crypts of coral reef were first found in beachrock on Shuiwei ridge, Luhuitou Peninsula. This kind of microbialites is a special one and different from microbialites found in beachrock on Heron Island by Webb et a1（1999）. The growth pattern of microbialites was discussed and divided into 5 growth phases. The discovery of the microbialites in the beachrock suggests a clear microbial origin for certain carbonate cements. Three types of the endolithic microbial borings were preserved in the coral reefs and seashells of the beachrock. Seashells collected from Shuiwei ridge beachrock containing microborings appear to have preserved most of their original fibrous and prismatic shell texture. Microborings in beachrock can be interpreted as microbial tracks and indicate that microbial play an important role during the forming of the beachrock.