摘要
库车盆地铜成矿作用发生在新近纪,主要有砂岩型、泥岩型、灰岩型铜矿化。矿化主要分布于盆地南部的秋里塔格构造带和北部的克拉苏构造带,基本位于背斜核部偏两翼部位,沿近东西向的断裂带呈带状分布,发育在盐丘附近。主要的地表铜矿物为氯铜矿,是干旱气候条件下含盐盆地的产物。盆地古近系石盐、石膏样品电镜分析、石膏铜含量化学分析及新近系碎屑岩中铜含量变化分析结果表明:盐岩、膏岩,褐红色碎屑岩(粉砂岩、泥质粉砂岩、泥岩)为铜的矿源层,灰绿色粉砂岩、泥岩、灰白色(含砾)中粗砂岩为铜的含矿层。铜离子的运移载体主要为源自大气降水溶解石盐、石膏所形成的卤水,卤水淋滤褐红色碎屑岩中的铜并下渗到地下,在以构造挤压为主及盐构造卸负作用产生流体上涌的驱动力下沿断裂向地表运移,随着卤水温度压力降低,干旱气候条件下,在地表碎屑岩节理面、部分层理面上发育石盐、石膏及氯铜矿,形成地表砂岩型、泥岩型、灰岩型铜矿化。当含铜卤水经过被方解石交代的硬石膏带(氧化-还原化学障)时,遇到因TSR反应形成富含还原硫的卤水,铜会发生富集,可能形成地下铜矿体。
The copper mineralization of the Kuqa foreland basin took place mainly in the Neogene period,and main mineralization includes sandstone type,mudstone type,and limestone type.The mineralization occurring in two tectonic zones（Qiulitage in the south and Kelasu in the north of the Kuqa basin）can be found mainly in two wings of the anticline.The mineralization is distributed along the near east-westtrending fracture zone and is developed around salt dome.The main copper mineral is atacamite on the surface,which is the product of salt basin in droughty climate conditions.This study analyzed halite and gypsum of Paleogene System using electronic microscope,copper content of gypsum,and change of copper in clastic rock using geochemical method.The result shows that that salt,gypsum,maroon clastic rock （including fine sand stone,siltstone,and mud stone）are source bed of copper,and celadon siltstone,mud stone,and hoar medium-and coarse-grained sandstone are Cu-bearing beds.Brine dissolved from formation of halite and gypsum by meteoric water is the major carrier of copper icons.Copper eluviated by brine from maroon clastic rock penetrates underground,and then migrates upward to ground driven by upwelling of fluid discharged from structure extrusion and salt tectonics.As temperature and pressure of brine decreases,halite,gypsum,and atacamite form along the joints of clastic rock and part beddings under the dried condition,forming sandstone-type,mudstone-type,and limestone-type mineralization on the surface.When the Cu-bearing brine passes by anhydrite belt replaced partly by calcite,reduced sulfur brine forms due to TSR reaction.Therefore,copper is enriched,likely forming underground copper orebodies.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2010年第12期1791-1804,共14页
Acta Geologica Sinica
基金
中国地质科学院矿产资源研究所所长基金项目(编号K0807)
国家"十一五"(编号2006BAB07B06)资助成果
关键词
前陆盆地
铜矿化
卤水
来源及富集
foreland basin
copper mineralization
brine
origin and enrichment
作者简介
曹养同，男，1975年生。博士，矿物、岩石、矿床学专业。通讯地址：100037，中国地质科学院矿产资源研究所；Email：cyt1941@yahoo．com．cn。
