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山东平邑盆地在白垩纪末期源于周缘蒙山和尼山2个隆起区的物源碎屑供给量减少,长期维持清澈湖水环境而有利于湖相灰岩沉积。柏林剖面卞桥组1段下亚段为百余米厚的湖相灰岩序列,其中的大部分核形石是通过湖底钙质微生物粘结作用形成的。本研究发现这里还存在暴露于湖面之上的泉华沉积,部分泉华周边低洼处出现丰富的包壳粒,以大小不同的核形石最常见,主要是通过超饱和碳酸钙泉水化学结晶过程形成的,有的泉华周缘也未能发现核形石,如此看来泉华型核形石分布具有局限性。
In the end of the Cretaceous, the Pingyi basin in Shandong Province is surrounded by the supply of debris from the two uplifted areas of Mengshan and Nishan uplifts, and the long-term maintenance of the clear lake environment is favorable to the deposition of lacustrine limestone. The lower segment of the first member of the Bianqiao Formation in the Berlin section is a lacustrine limestone sequence of over a hundred meters in thickness. Most of the nucleoids are formed by the lacustrine calcareous microbial binding. In this study, we found that there is also the Quanhua sediments exposed on the lake surface, some of which are abundant in the low-lying areas around the Quanhua, and the most common types of nuclei are the chemical crystallization process of the supersaturated calcium carbonate springs Formed, and some Quanzhou periphery also failed to find the core-shaped stone, so it appears Quanhua-type distribution of nuclear stone has its limitations.