辽宁青城子姚家沟钼矿流体特征及成矿深度估算

发布时间：2018-06-04 20:24

  本文选题：辽宁青城子 + 姚家沟钼矿　； 参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：姚家沟钼矿是辽宁青城子矿田中近年来新发现的矿床,位于华北克拉通北缘,辽东裂谷带,钼矿床的发现为青城子矿田的地质勘探提供了新的方向。矿床蚀变分带特征明显,主要有石英核、钾化花岗岩带、绿帘石化花岗岩带以及矽卡岩化带,钼矿化主要在钾化带及矽卡岩化带中。姚家沟岩体具有多期侵入的特征,其中UST石英脉和石英眼是姚家沟岩体出溶热液的证据。观测到6期流体活动,石英眼(早期)→钼矿化石英脉(成矿期)→无钼矿化石英脉(后期)→方解石脉(晚期)→硬石膏脉,UST石英脉可能与钼成矿关系不大。存在5种类型流体包裹体:除纯CO2包裹体外,早期均一温度211.4~515.4℃,盐度0.8~19.2wt%Na Cleqv;成矿期均一温度179.5~424.5℃,盐度2.4~21.5wt%Na Cleqv;后期均一温度范围167.8~353.3℃,盐度3.4~15.8wt%Na Cleqv;晚期均一温度132.5~234.1℃,盐度为0.9~11.2wt%Na Cleqv;UST脉均一温度158.6~381.7℃,盐度1.6~21.5wt%Na Cleqv。激光拉曼测试结果表明流体包裹体中主要含有H2O,还发现有CO2、CO32-、HCO3-、CH4,固相成分有黄铜矿、针铁矿、石英等,早期流体为中高温中低盐度富挥发份(CO2)体系,具弱碱性,在成矿期,流体温度、压力、盐度降低,CO2逸失,体系还原性增强,金属元素大量沉淀下来;到后、晚期,流体温度、盐度、CO2含量进一步降低,氧化性逐渐增强,在方解石脉中已没有CO2包裹体,最后表现出强氧化性,产生硬石膏。流体不混溶、围岩蚀变和流体混合作用是金属元素沉淀的主要机理。用等容线相交法估算捕获压力,早期为220~145MPa;成矿期180~124 MPa;后期115~60MPa;UST脉148~78MPa。成矿期成矿深度估算为7~4.6km。氢氧同位素研究表明,成矿期流体为岩浆水与大气降水或变质水混和形成,对比燕辽成矿带其他钼矿床,其成矿流体来源上具有相似性。
[Abstract]:Yaojiagou molybdenum deposit is a newly discovered deposit in Qingchengzi ore field of Liaoning Province in recent years. It is located in the northern margin of North China Craton and in the Liaodong rift zone. The discovery of molybdenum deposit provides a new direction for geological exploration of Qingchengzi Orefield. The characteristics of alteration zones are obvious, including quartz core, potash granite zone, green curtain granite belt and skarn zone, and molybdenum mineralization mainly in kalitization zone and skarn zone. The Yaojiagou rock body is characterized by multiple intrusions, among which the UST quartz vein and quartz eye are the evidence of the exsolution hydrothermal solution of the Yaojiagou rock body. It is observed that fluid activity in stage 6, quartz eye (early) molybdenum fossil vein (ore-forming period) and molybdenum fossilized quartz vein (late stage) calcite vein (late) anhydrite vein and UST quartz vein may not be related to molybdenum mineralization. There are five types of fluid inclusions: except for pure CO2, the early homogenization temperature is 211.4% 515.4 鈩，

本文编号：1978713