摘要
太平沟斑岩型钼矿床位于大兴安岭北段,处于东西向古生代古亚洲构造成矿域和北北东向中新生代滨西太平洋构造成矿域的转换、叠合部位。该矿床形成于131.5～127.5Ma,是大陆内部构造-岩浆活化的产物,成矿系统发育于早白垩世初期华北及中国东部构造体制由挤压向伸展转变的背景下。太平沟钼矿的流体成矿过程包括早、中、晚3个阶段,分别以石英-黄铜矿-黄铁矿、石英-黄铁矿-辉钼矿和石英-碳酸盐组合为特征。石英中发育水溶液型、含/富CO_2型和含子矿物型流体包裹体,子矿物包括石盐、黄铜矿等,但晚阶段仅发育水溶液型包裹体。成矿早、中、晚各阶段流体包裹体的均一温度分别集中在320～390℃、240～320℃和140～200℃,盐度变化为从>66.8 wt%NaCl eqv.、2.4 wt%～33.8 wt%NaCl eqv.到<10 wt%NaCl eqv.。流体系统由早阶段的高温、高盐度、富CO_2的岩浆热液,经流体沸腾、CO_2逸失、温度降低等过程导致大量金属硫化物沉淀,演化为晚阶段低温、低盐度、贫CO_2的大气降水热液。
The Taipinggou Mo deposit occurs in the northern Great Hinggan Range, China, where is all area the NNE-trending Mesozoic-Cenozoic Circum-Pacific belt superimposed on and/or transitioned front the EW-trending Paleozoic Central Asian orogenic belt. The Taipinggou porphyry Mo deposit was formed during 131.5 similar to 127.5Ma when the tectonic setting changed front Compression to extension in North China and eastern China. The hydrothermal ore-forming process of the Taipinggou deposit includes three stages, i. e. early middle and late stages, characterized by mineral assemblages of quartz-chalcopyrite-pyrite, quartz-pyrite-molybdenite and quartz-carbonate, respectively. In hydrothermal quartz three types of fluid inclusions can be observed. They are NaCl-H(2)O solution, CO(2)-bearing or CO(2)-rich and daughter mineral-beating fluid inclusions. Daughter minerals include halite, chalcopyrite and some other uncertain species. The latter two types fluid inclusions cannot be observed in the late-stage quartz. Homogenization temperatures of fluid inclusions vary from 320 similar to 390 degrees C early, through 240 similar to 320 degrees C middle, to 140 similar to 200 degrees C late, with salinities up to 66.8 wt% NaCl eqv. early, to 2.4 wt% similar to 33.8 wt% NaCl eqv. middle, and to < 10 wt% NaCl eqv late, respectively. In one word, the early-stage fluids were magmatic in origin and characterized by high temperature, high salinity and CO(2) rich, and boiled in early-middle stage, resulting CO(2) release, temperature decrease and rapid precipitation of ore-forming materials. Finally the fluids evolved into late-stage meteoric water with low temperature, low salinity and low content of CO(2).
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第10期2621-2630,共10页
Acta Petrologica Sinica
基金
国家重点基础研究发展规划项目(2006CB403506课题)
内蒙古太平沟铜钼矿勘查项目(H90004)
高等学校学科创新引 智计划(B07011)资助
