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兰坪盆地金顶超大型铅锌矿床广泛发育特征特殊的角砾岩和含角砾砂岩,前人对其成因有不同的认识。本文在矿区岩相构造填图的基础上,根据岩石角砾、杂基、胶结物成分和结构特点,划分出以下8类岩石:(1)层状含灰岩角砾砂岩,(2)方解石胶结灰岩砾角砾岩,(3)石膏/硬石膏胶结灰岩砾角砾岩,(4)铁泥质胶结灰岩砾角砾岩,(5)混杂状砂质胶结灰岩砾角砾岩(或称含灰岩角砾砂岩),(6)膏砂泥胶结复成分砾角砾岩,(7)砂质胶结复成分砾角砾岩,(8)含矿石砾角砾岩。其中,含矿石角砾岩形成于矿后,而其它角砾岩形成于矿前且可能近同期形成。角砾岩均处于下部“原地”和上部“外来”地层系统之间。研究认为含矿石砾角砾岩为矿后垮塌成因,其它角砾岩为(含砂)膏盐底辟成因,或含砂膏盐底辟破碎围岩、携带角砾流动的产物。目前角砾岩砂质杂基间的方解石胶结物和灰岩角砾间的方解石胶结物,可能为后期含有机质流体与先存的、作为胶结物的膏盐反应形成。这一过程同时产生H2S,对后期成矿具有重要意义。角砾岩的矿化与膏盐底辟体有关,具“单中心”分带、“多中心”叠加的特点。矿化主要为闪锌矿、方铅矿、黄铁矿等热液矿物交代角砾岩间或砂质杂基间的方解石胶结物,角砾本身弱/无矿化。比较而言,层状含灰岩角砾砂岩为含矿最普遍,次为方解石胶结灰岩砾角砾岩、铁泥质胶结灰岩砾角砾岩、含矿石砾角砾岩,混杂状砂质胶结灰岩砾角砾岩局部含矿。
The Jinding Ultra-large Lead-Zinc deposit in Lanping Basin has widely developed breccias and breccia-bearing sandstones, and their predecessors have different understandings of their causes. Based on the lithofacies tectonic mapping in the mining area, the following eight types of rocks are classified according to the rock breccia, miscellaneous base, cement composition and structural features: (1) layered limestone breccia sandstone, (2) calcite cementation Limestone conglomerate breccia, (3) gypsum / anhydrite cemented limestone breccia breccia, (4) ironiferous cemented limestone breccia breccia, (5) mixed sandy cemented limestone breccia breccia (Or limestone-bearing breccia sandstone), (6) gypsum cemented breccia breccia, (7) sandy cemented composite gravel breccia, and (8) ore-bearing gravel breccia. Among them, the ore-bearing breccias formed after the ore, while other breccias formed in the mine and may form nearly the same period. Both breccias are between the lower “in situ” and the upper “extraneous” stratigraphic systems. It is considered that the ore-bearing breccia breccia is the cause of post-mine collapse, and the other breccias are the salt diapirite origin of the (sand-bearing) gypsum, At present, the calcite cement between calcareous sandstone and the calcite cement between limestone breccia may be formed by the reaction of later organic-containing fluid with the pre-existing gypsum as cement. This process produces H2S at the same time, which is of great significance to the later mineralization. The mineralization of breccia is related to gypsum salt diapirism, with the characteristics of “single center” and “multi-center” superposition. Mineralization is mainly the sphalerite, galena, pyrite and other hydrothermal minerals account for between the breccia or sandy heterogeneous calcite cement, breccia itself weak / no mineralization. In comparison, layered limestone-bearing breccia sandstones are the most common minerals, followed by calcite-bound limestone breccia breccia, ironiferous cemented limestone breccia breccia, ore-bearing breccia breccia, miscellaneous sandy Cemented limestone breccia breccia local ore-bearing.