The study area is located in the Upper Yangtze region of the Yangtze block. Abundant sedimentary mineral resources are preserved in the early Middle Permian Liangshan Formation and among them bauxite deposits are of favorable prospects for exploration and exploitation. In order to reveal the relationship between the deposition and distribution of the bauxite deposits and the lithofacies paleogeography of early Middle Permian period, the authors studied the sedimentary, distribution and ore-bearing features of the Liangshan Formation, compiled a lithofacies paleogeographic map and established a metallogenic model for bauxite deposition in behind-barrier lagoon. The paleogeographic framework shows that the study area dipped southwards, the land was located in the north and the sea lay in the south, with the development of a barrier lagoon system. The lagoon deposirional system was located in the north, the barrier depositional system was situated along Ludian-Weining-Guiyang-Duyun zone, and the common sea depositional system was developed in the south. Altogether 7 sedimentary subfacies nave been recognized, which include uplift, coastal lake, shallow lake, semi-deep and deep lake, barrier, inner shelf sea and outer shelf sea. Almost all bauxite deposits are located in the semi-deep and deep lake region of the lagoon in the north, obviously controlled by lithofacies paleogeography.%研究区位于扬子陆块上扬子区,中二叠世早期地层梁山组产有丰富的沉积矿产,其中铝土矿具有良好的勘探开发前景.为了揭示区内中二叠世早期铝土矿的形成、分布与岩相古地理的关系,对区内梁山组的沉积特征、展布规律和含矿性进行了研究,编制了中二叠世早期梁山组岩相古地理图,提出了区内铝土矿障壁后泻湖成矿的模式.结果表明,区内古地理格局具有北高南低、南海北陆的特点,鲁甸—威宁—贵阳—都匀一线为障壁沉积体系,北部为障壁后泻湖沉积体系,南部为正常浅海沉积体系,大致可划分为隆起、滨湖、浅湖、半深湖—深湖、障壁砂坝、内陆棚和外陆棚7个沉积亚相,铝土矿矿床全部分布于北部泻湖半深湖—深湖相区内,岩相古地理控矿作用明显.
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