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甘肃冰沟门异常区在晚二叠世晚期肃南组(P_2~s)时发育了两种类型古河流。以大磁窑河为代表的网状支流河,蚀源区铀源丰度低,河床坡降大,流程短,水流急,不利于铀矿化的形成。古梨园河发育的中-晚期为低-高弯蛇曲河,边滩发育,规模适中(河宽<300m),铀源丰富,河水中富含植物碎屑等有机质,铀在沉积一成岩阶段于河流转弯处和主、支流交汇处形成聚集,为后生阶段的工业富集提供了良好的前提。
In the area of the Binggoumen anomaly in Gansu, two types of ancient rivers were developed during the late Permian Sunan Formation (P 2 ~ s). Mesozoic tributary rivers, represented by the Daciyue River, have low abundance of uranium source in the source area, large riverbed decline, short flow and acute water flow, which is not conducive to the formation of uranium mineralization. The ancient Liyuan River is characterized by low-high curved snake-shaped river in the middle-late stage with a wide margin beach (river width <300m), abundant uranium source and rich phytoliths in river water. During the sedimentary-diagenetic stage At the bend of the river and at the junction of the main and tributaries, it forms a good premise for industrial enrichment in the later stage.