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中文摘要: 滇西北泸水锑矿为笔者近年在该地区进行找矿勘探过程中新发现的矿点,其赋矿围岩为一套初糜棱岩,断裂控矿,辉锑矿与黄铜矿、黄铁矿、石英共生。为确定其成因类型,笔者对主成矿期石英和硫化矿进行了H-O-S同位素研究。结合野外矿体产出形态,可以将研究区划分出2期成矿作用,①早期以浸染状为特征,顺糜棱岩片理就位,②主成矿期为细脉状,产于与糜棱岩片理垂直的石英脉中。石英包裹体水δD值介于-95.4‰～-88.8‰之间,δ18OH2O值主要在-10.25‰～-9.75‰之间,在δD VS.δ18OH2O图解中,含矿热水溶液H-O同位素的投影点主要落于大气降水线附近。黄铁矿δ34S值≈4.1‰～4.9‰,辉锑矿样品的δ34S值≈1.2‰～1.3‰,总硫值为2.23‰,具有深部岩浆硫特征。前人对赋矿糜棱岩测年,得到其成岩年龄和变质年龄分别为42 Ma和38 Ma,研究区辉锑矿-石英脉构造控矿明显,说明其成矿年龄应该小于38 Ma。喜山期青藏高原及其周边锑矿床多与斑岩体有关,研究区附近有斑岩体的存在,结合其H-O-S同位素特征,可以判断泸水锑矿可能经历了两次成矿事件,早期与斑岩体有关,后期收到了大气降水的改造。
Abstract:Lushui antimony deposit in Northwest Yunnan is a newly discovered ore spot. Its host rock is a set of primary mylonite, it is a fault-controlled deposit. In order to determine the genetic types of the Lushui antimony deposit, H-O-S isotopes of quartz and sulphide ore were studied. Combined with the field orebody formation, the study area can be divided into two stages of metallogenesis, ① In the early age, the ore body hasSimpregnated structure, and born in the mylonite foliation, ② in the main ore-forming period, the ore body is vein-like, associated with quartz vein which is perpendicular to Mylonite schist direction. The δ D value of quartz is between -95.4 ‰ and 88.8 ‰, and δ18OH2O value is mainly between -10.25 ‰ and 9.75 ‰. In the diagram of δD VS. δ18OH2O, the projection point of H-O isotope mainly falls near the precipitation line. The δ34S value of pyrite is about 4.1‰ ~ 4.9‰, the δ34S value of stibnite sample is about 1.2 ‰~1.3 ‰ and the total sulfur value is 2.23 ‰, which is characterized by deep magmatic sulfur. The age of diagenesis and metamorphism are 42 Ma and 38 Ma, respectively. The tectonic control of stibnite and quartz vein in the study area is obvious, indicating that the metallogenic age should be less than 38 Ma. The antimony deposits in and around the Xishan Qinghai-Tibet Plateau are mostly related to the porphyry. The existence of the porphyry in the vicinity of the study area, combined with its H-O-S isotopic characteristics, the author judges that the Lushui antimony ore may have undergone two metallogenic events, which are related to the porphyry in the early stage. The retrofit of atmospheric precipitation was received in the later period.
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