鲕粒是碳酸盐岩中最普遍的包覆颗粒之一,其成因一直是地质学家们关注的重要科学问题之一,对解释沉积环境具有重要的意义.北京西郊下苇甸剖面寒武系发育多期叠层石生物丘(层),对其进行研究发现,在崮山组上部和凤山组下部叠层石生物丘(层)中发育有大量的底栖鲕粒.分析其产出特征及微观组构形态,认为底栖鲕粒的形成与微生物作用有密切的关系,更多地支持了鲕粒微生物成因的观点,同时也增加了碳酸盐颗粒的多样性.在前人研究的基础上,追索该发现的科学含义,为深入了解微生物碳酸盐岩的形成与微生物席沉积学提供有益的线索.%Ooids are one of the common particles in coating grains in carbonate rock. The origin of ooids has been one of the most important scientific problems to which the geologists have paid close attention. It is very important to know and explain the sedimen-tary environment. There are multi-period stromatolitic biostromes or stromatolitic bioherms in the Cambrian strata at the Xiaweidian section in the western suburb of Beijing. The authors found that benthic ooids are largely developed in the top part of the Gushan Formation and the lower part of the Fengshan Formation. An analysis of their formation characteristics and microscopic fabric patterns shows that the origin of benthic ooids was closely related to microbial action, thus supporting the hypothesis of microbes to some ex-tent. What is more, the discovery increases the diversity of the carbonate particles. On the basis of previous researches, the authors have traced the scientific meaning of this problem so as to provide some useful clues for thorough understanding of the form of micro-bial carbonate and microbial-mat.
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