兰坪盆地金顶铅锌矿床砂岩型矿石的沉积特征与粒度特征  

Depositional Features and Grain Size Characteristics of Sandstone-Type Ore of Jinding Pb-Zn Deposit in Lanping Basin

作　　者：刘腾[1] 何珍明 刘远超[1] 曹姝璐 

机构地区：[1]东华理工大学地球科学学院,江西南昌

出　　处：《自然科学》2015年第4期203-213,共11页Open Journal of Nature Science

基　　金：国家自然科学基金项目(41362008、U0933605);东华理工大学研究生创新项目(YC2014-S338)联合资助。

摘　　要：金顶超大型铅锌矿床主要由角砾岩型和砂岩型两类矿体组成,但容矿岩石的成因及归属等问题尚不明确。利用粒度资料进行沉积物的粒度结构分析,可以有效地判定沉积物搬运方式、判别水动力条件、区分沉积环境类型,研究沉积物的成因机制。本文通过绘制粒度概率累计曲线图、C-M图等图件,详细研究了砂岩型矿石的粒度特征,确定了其沉积水动力类型,结合砂岩型矿体的构造背景、矿石显微构造等特征,探讨了砂岩型矿石的成因,研究表明砂岩型矿石属于细砂-粉砂岩,平均粒径为1.526Φ,正偏态或很正偏态,物质来源为河砂;从萨胡环境判别公式以及C-M图解中,可以看出研究区砂岩以重力流沉积为主;认为它是碎屑物质以重力流方式搬运并在快速水流作用下与底部物质混合、再悬浮、沉积而形成。Jinding super-large Pb-Zn deposit is mainly composed of breccias-type and sandstone-type ore body, but the genesis and ownership of ore-hosted rocks are still unclear. The utilization of grain- size data to analyze the structure characteristics of the sediment grains can effectively determine the transport mode of sediments, judge the hydrodynamic conditions, distinguish the sedimentary environments, and analyze the genetic mechanism of sediments. Based on the probability cumulative grain-size curves and C - M graph, the authors studied in detail the grain-size characteristics of sandstone-type ore, and defined its sedimentary hydrodynamic type, then combined with the tectonic background of the sandstone-type ore body and ore microscopic structure characteristics, the genesis of sandstone-type ore was discussed. The result shows that the sandstone-type ore belongs to the fine sandstone-siltstone, the average particle size of 1.526Φ, positive skewness or very positive skewness, and material source for river sand. From Sahu environment discriminant and C - M graph, it can be seen that the sandstone in the study area is given priority to gravity flow deposits. The result shows that the sandstone is formed by fragmentary material handling in gravity flow and mixed with the bottom material, resuspension and sedimentary under the action of rapidly water.

关 键 词：粒度分析 沉积环境 重力流沉积 金顶铅锌矿床 

分 类 号：P61[天文地球—矿床学]