楚雄盆地砂岩型铜矿床地质地球化学及找矿预测研究

【作者】 吴鹏；

【导师】 韩润生；

【作者基本信息】 昆明理工大学 ， 矿产普查与勘探， 2009， 博士

【摘要】 博士论文《楚雄盆地砂岩型铜矿床地质地球化学及找矿预测研究一以六苴、郝家河矿床为例》,依托全国危机矿山接替资源项目“云南省大姚县六苴铜矿小河-石门坎矿段接替资源勘查”(项目编号：200453001)与“云南省牟定县郝家河铜矿接替资源勘查”(项目编号：200653098)选题。以六苴、郝家河床为研究对象,在矿床地质特征研究基础上,总结了矿区构造演化及控矿规律。对比了不同矿床、不同层位、含矿层不同位置元素地球化学特征,利用流体包裹体及同位素地球化学资料研究成矿流体的性质。结合电子探针分析结果,讨论含矿层浅、紫色砂岩的形成、金属矿物及元素分带机理,借鉴砂岩型铀矿床研究成果,提出“紫化聚铜”成矿模式。采用钻孔地球化学方法建立地球化学异常模式,结合地表地球化学勘查及地质综合分析,对研究区铜矿床深部及外围进行找矿预测,取得良好找矿效果。1、阐述了“牟定斜坡”与楚雄盆地弧形砂岩铜矿带的空间关系。认为“牟定斜坡”沉积环境有利于铜质预富集。其构造作用控制砂岩型铜矿床的形成。2、详细厘定了矿区出露地层的划分标志及依据。含矿层(K2ml1、K2mx2)以浅色砂岩为主,顶、底均以灰紫色含砾中-粗粒砂岩为其特征标志。3、总结了构造演化及控矿规律。早期近东西向挤压形成的近南北向压扭性构造促进了铜的活化、迁移。晚期的构造活动改造,使铜矿体加富。后期近东西向压扭性断裂破坏矿体,将其向全浅带一侧错动。4、矿床地球化学分析认为,含矿层砂岩经历了两种流(气)体活动过程：①还原性气(液)作用下砂岩褪色(砂岩由紫变浅)；②从紫色砂岩一侧进入的含氧层间流体。矿床形成于中低温环境,成矿流体具低盐度,以大气降水为主。成矿流体运移方向为从紫色砂岩一侧进入,向浅色砂岩一侧运移。提出“紫化聚铜”成矿模式。5、采用钻孔地球化学方法建立地球化学异常模式,结合地表地球化学勘查及地质综合分析,圈定郝家河A、B、C三区,郝家河-老虎硐铜矿带,六苴石门坎NW侧,簸箕背斜、大雪山背斜倾没端等找矿预测区,部分已得到工程验证。更多还原

【Abstract】 This doctoral dissertation, Studying on the Geology and Geochemistry, and the Prospecting Prognosis for the Sandstone Copper Deposit, in the Chuxiong Basin—Taking Liuju and Haojiahe Copper Deposit As the Case, is based on the Project of Superseding Resources Exploration for the State Crisis Mine—"Superseding Resources Exploration to the Xiaohe-Shimenkan Ore-body in Liuju Copper Deposit, Daoyao,Yunnan Province(NO.200453001)" and "Superseding Resources Exploration to the Haojiahe Copper Deposit, Mouding,Yunnan Province(NO.200653098)". Study on the geology and geochemistry, and the prospecting prognosis has guiding significance for metallogenic mechanism of sandstone copper deposit and exploration of copper resources in the Chuxiong Basin.Take the Liuju and Haojiahe copper deposits as study objects; based on the geological features of deposit, it summarized the tectonic evolution and ore-controlling regularity in study area. Element geochemistry characteristics in different deposits and different color rocks were contrasted. The data of fluid inclusion and isotope geochemistry was used for the study of ore-forming fluid. On the basis of the electron probe analysis and sandstone-type uranium deposit research results, this paper discussed the formation of mauve sandstone and grayish sandstone, and the mechanism of mineral and element zonation. It builted the metallogenic model of the deposit, that is "copper aggregation during sandstone mauve alteration".By adopting geochemical sections method from drill holes, it established the geochemical anomaly model. Combination with surface geochemical exploration and the synthetical geology analysis, it gained a good effect on prospecting prognosis in the deep and periphery.1. It expounded the spatial relationship between the "Mouding Slope" and Arcuate Sandstone Copper Belt in Chuxiong Basin. The sedimentary environment of "Mouding Slope" was favorable to copper preconcentrtion. The tectonism controlled the formation of sandstone copper deposit.2. It defined the exposure strata in detailed, and put forward the dividing indexes. Grayish sandstone was the main version in ore-bearing strata (K2m11、K2mx2), which is mauve pebbled and medium to coarse grained sandstones at the top and the bottom.3. It summarized the tectonic evolution and ore-controlling regularity. The Nearly North-South compresso-shearing structures lead to copper activation and transport, and ore bodies reenrichment by late tectonic reworking. The Nearly East-West compresso-shearing faults formed in the last stage pushed ore-bodies to the grayish bed.4. Analyzed of ore deposit geochemistry show that ore-bearing strata had experienced two processes fluid flow:①.Fading sandstone formed by reductive fluid (from mauve to grayish);②. Interlayer oxidative fluid came from the mauve direction. The sandstone copper deposit was formed in mid-low-temperature environmental, and ore-forming fluid derived from meteoric water, with low salinity. Ore-bearing hydrothermal solution came from the mauve direction and toward to the grayish direction. It builted the metallogenic model of the deposit, that is "copper aggregation during sandstone mauve alteration"5. By adopting geochemical sections method from drill holes, it established the geochemical anomaly model. Combination with surface geochemical exploration and the synthetical geology analysis, it enclosed prospecting areas, such as Haojiahe A, B, C block; Haojiahe-Laohudong belt; northwest side of Shimenkan; pitching end of Boji and Daxueshan anticline, which had taken good effect by field examination.更多还原