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南盘江盆地中的大贵州滩为一个自晚二叠世末期开始发育,至晚三叠世初期停止生长的孤立型碳酸盐岩台地。早期的研究工作主要集中于台地内部、北部斜坡和盆地边缘,并认为大贵州滩下三叠统地层格架的几何形态近于对称。本次研究以下三叠统岩石地层对比为基础,借助早三叠世期间δ13C波动频繁且幅度较大的特点进行化学地层对比后发现:台地南缘二-三叠系地层为不整合接触,南缘下三叠统的地层缺失严重;与之前的认识不同,台地南、北两缘下三叠统的地层格架的几何形态表现出明显的不对称特点。
The Great Guizhou Beach in the Nanpanjiang Basin is a solitary carbonate platform that developed from the late Pleistocene to the end of the last Triassic. Earlier research focused on the interior of the platform, the northern slope and the basin margin, and concluded that the geometry of the Strata Triassic stratigraphic framework in the lower margin of the DaGuizhou is nearly symmetrical. Based on the comparison of the following Triassic lithostratigraphic stratigraphy, based on the chemical stratigraphic correlation of δ13C fluctuating frequently during the Early Triassic, the two-Triassic strata in the southern margin of the platform are unconformity contacts. The Triassic strata in the margin have a serious lack of stratigraphy. Different from previous understanding, the geometry of the Triassic stratigraphic framework in the south and north margin of the platform shows obvious asymmetry.