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早奥陶世桐梓红花园剖面位于扬子区的内陆架沉积带,碳酸盐岩相的桐梓组浅滩序列中频繁出现强水动力环境下三叶虫、棘皮类、腕足类、砾屑和鲕粒单独或混合构建的沉积单元,有些滩相单元是在高能带风暴浪中快速堆积的,间或出现有云坪带沉积的白云岩。盐度异常和强水动力条件皆不利于后生动物造礁,仅见薄层钙质微生物席。通过与红花园之南的贵阳乌当以及之北的桐梓水坝塘剖面桐梓组的岩相学比较,厘定它们分别由蒸发云坪为主—高能滩为主—潮下带为主的相变序列构成,藉此划定桐梓组沉积期由南到北古地理背景差异性,认为朝北方向海水有逐渐变深的趋势,水深控制了白云岩化强度和海水能量指标。
The Early Ordovician Tongzihong Garden section is located in the inland shelf sedimentary zone of the Yangtze area. Frequent occurrence of trilobites, echinoderms, brachiopods, gravel and oolites in the Tongzi Formation shoal of carbonate facies frequently occurs Sediment units built separately or in combination, some of which are rapidly accumulating in high-energy storm surges with interbedded or dolomitic dolomites deposited. Abnormal salinity and strong hydrodynamic conditions are not conducive to the metazoan reefs, only see the thin layer of calcium microbial seats. By comparison with the petrography of the Tongzi Formation in Wudang, Guiyang in the south of Red Garden and the Tongzi Dam in the north of the Red Garden, the phase transition sequences dominated by evaporative clouds, high energy beach and subtidal zone are determined , The authors delineate the difference of the paleogeographic background from south to north in the sedimentary period of Tongzi Formation. It is considered that the seawater in the northward direction has a gradual deepening trend, and the water depth controls the dolomitization intensity and seawater energy index.