萨瓦亚尔顿金(锑)矿床地质地球化学特征与成矿机理探讨

GEOCHEMISTRY AND METALLOGENIC MECHANISM OF THE SAWAYAERDUN GOLD ANTIMONY DEPOSIT

新疆萨瓦亚尔顿金（锑）矿床是９０年代初在我国南天山西段发现的大型金矿，其成矿地质背景、矿床地质特征与乌兹别克斯坦穆龙套金矿床具有类似的特点。通过对该矿床地质地球化学特征进行研究分析，指出成矿与含碳浊积岩有关，矿体受一组早期为韧性、中晚期为脆性的剪切带控制。成矿与深部的热源的驱动有关，成矿流体成分具有深部来源与浅部来源混合特点，主成矿期为海西晚期—印支期。

Discovered at the beginning of 1990s, the Sawayaerdun gold antimony deposit located in Alai Mountain in the west of South Tianshan Mountains of Xinjiang is a large gold deposit. Hosted in the carbonaceous turbidite enriched with Au, Sb, Ag, the deposit is similar to the Mulongtau gold deposit of Uzbekstan in regional geological setting and mineral deposit characteristics. It is controlled by a series of shear zones with early ductile and later brittle characteristics. Researches on mineral fluid inclusions show that ore forming fluid components are complex, belonging to H 2O-CO 2-Na +-K +-Cl - type or H 2O-CO 2-Na +-Ca 2+ -Mg 2+ -HCO - 3-Cl --SO 2- 4 type. The Au, Sb, Ag content of ore forming fluids was over 12 times higher than that of early quartz carbonate veins. δ 34 S CDT of ore is close to 0‰, which represents the character of homogenized crust derived sulfur. The lead isotope ratios of most ore sulfides show that they are of crustal origin and came mainly from the depth of the crust. Some samples are similar to enclosing rocks with their lead isotope ratios exhibiting features of mature island arc. The homogenization temperatures of the ore forming fluids vary from 100℃ to 300℃, mostly being 155～220 ℃ and 260～290 ℃. δ 13 C CO 2 of ore forming fluids varies from -8 7‰ to -2 4‰, averaging -5 5‰, and δ 18 O CO 2 of ore forming fluids varies from 14 5‰ to 24 2‰, implying that carbon was also derived from the depth of the crust. δ 18 O H 2O in the quartz associated with ore varies from -1 1‰ to +5 7‰, and δ D varies from -84‰ to -59‰. In the δ 18 O H 2O versus δ D diagram, most samples are distributed on the right side of the meteoric water line, suggesting that the ore forming waters are mixtures of water from the depth (probably magma) and meteoric water. According to these geochemical characteristics, the authors consider that a magmatic chamber probably exists in the depth of the ore district, the metallogeny is related to the motion of the heat source in the depth and the ore forming fluid composition is characterized by the mixture between material from the depth and that from the shallow part of the crust. In addition, the Rb Sr isochron dating indicates that the main ore forming process took place between Late Variscan and Indosinian.