金顶超大型铅锌矿床角砾岩及含角砾砂岩分类、特征及成因  

Classification,Characteristics and Genesis of Breccias and Breccia-Bearing Sandstone in the Giant Jinding Zn-Pb Deposit of Southwestern China

作　　者：庄天明[1,2] 宋玉财[2] 侯增谦[2] 薛传东[3] 韩朝辉[4] 张翀 程杨[6] 王哲 翟忠保 

机构地区：[1]烟台黄金职业学院,山东招远265401 [2]中国地质科学院地质研究所,北京100037 [3]昆明理工大学,云南昆明650093 [4]中国地质大学(北京),北京100083 [5]核工业化工冶金研究院,北京101149 [6]中国冶金地质总局矿产资源研究院,北京100031 [7]中国地质矿业总公司,北京100029 [8]中国水利水电第六工程局有限公司,辽宁丹东100029

出　　处：《地质与勘探》2016年第6期1001-1015,共15页Geology and Exploration

基　　金：国家重点基础研究规划项目(编号:2009CB421008);国家自然科学基金(编号:41273050;41373049;41320104004);IGCP/SIDA 600项目;国土资源大调查项目(编号:1220114010301;1212011220908;1212011121065)联合资助

摘　　要：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。There are many types of breccia with special compositions and textures （ some can be named breccia - bearing sandstone） in the giant Jind- ing Zn - Pb deposit. According to new field observations, this study classifies them into eight types in terms of the composition of the clast, matrix, and cement as well as the texture. These hreccias are ： （ 1 ） beddedlimestone clasts - bearing sandstone （bLSB） , （2） limestone clasts cemented by calcite （ LCB）, （3） limestone clasts cemented by gypsum/anhydrite （ LGB）, （4） limestone clasts with ferruginous and mudy matrix （ LFMB）, （5） chaotic limestone clasts with sand matrix （ or limestone clasts - hearing sandstone） （LSB） , （6） polymictic clasts with gypsum, and sandy and mudy matrix （PPB） , （7） polymictic clasts with sand matrix （PSB） , and （8） ores - bearing elusts with polymictic matrix. Temporally, the breccia as ores - bearing clasts with polymictic matrix was formed after the mineralization whereas the other breccias were formed before the mineralization or nearly in the same time. Spatially, all the breecias occur between the underlying, normal, and autochthonuus sequences, and the overlying and alluebthonous sequences. This study interprets that the breccia as ores - bearing clasts with polymlctic matrix is of post - ore collapsed origin. The other breccias are of salt diapir or- igin, or the salt diapir - realated origin that sand - bearing evaporite pierced the hanging wall rocks and transported the clasts to reach the surface, like open - toed sheet in the modern salt structural envirmxment. The present calcite cements between the sand matrix and limestone clasts in the breccias may be produced by the reaction between organic - rich fluid and pre - existing evaporite as cements. The mineralization of breccias is related to the salt diapir, which have the ＂slngle center ＂zoning and ＂multi center＂ superimposing features. Mineralization occurs in the cements between the sand grai

关 键 词：角砾岩 含角砾砂岩 成因 (含砂)膏盐底辟 兰坪盆地 金顶矿床 

分 类 号：P581[天文地球—岩石学] P588.2[天文地球—地质学]