滇东南含锰建造沉积相及聚锰条件分析

在对滇东南区域地质及锰矿研究成果综合分析的基础上, 以中三叠世拉丁期含锰建造的沉积相研究为基础, 把滇东南的法郎组中的锰矿总结为碎屑岩建造中的斗南式锰矿和碳酸盐岩建造中的白显式锰矿两类, 从解析典型锰矿床的沉积格局入手, 研究了中三叠世拉丁期典型矿床的岩相古地理特征。斗南锰矿形成于礁(滩)后泻湖的滨浅海碎屑岩建造相区、台地碳酸盐建造相区和斜坡碎屑岩建造相区中, 在斜坡碎屑岩建造相内多具有异地堆积的重力流沉积。白显锰矿形成于局限台地水体较为滞流的泻湖相-潮坪相中。在不同沉积格架下, 海水物理化学条件、水动力环境、生物作用和同生断裂活动是影响聚锰作用的重要因素。

An Analysis of Sedimentary Facies of Manganiferous Formation and Manganese Accumulation Conditions in Southeastern Yunnan

On the basis of an integrated analysis of the research achievements for regional geology and manganese deposits in southeastern Yunnan and in the light of the sedimentary facies study of manganiferous formation in Middle Triassic Latin period, the authors divided the manganese deposits in Falang Formation of southeastern Yunnan into two types, i.e., the Dounan type manganese deposits in detrital rock formation and the Baixian type manganese deposits in carbonate rock formation. Starting with the analysis of the sedimentary framework of typical manganese deposits, the authors studied the lithofacies and paleogrography of typical manganese deposits of Middle Triassic Latin period. The Dounan manganese deposit was formed in littoral-neritic detrital rock formation facies area of backreef lagoon, platform carbonate formation facies area and slope detrital rock formation facies area, with the last facies area containing lots of gravity flow sediments of heterochthonous accumulation. The Baixian manganese deposit was formed in the lagoon facies-tidal flat facies where confined platform water body was relatively stagnant. Under the conditions of different sedimentary frameworks, physical-chemical conditions of sea water, hydrodynamic environments, biological actions and contemporaneous faulting constituted important factors responsible for manganese accumulation.