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岔路口超大型斑岩型钼矿床位于大兴安岭北段,以网脉状和角砾岩型矿化为主.该矿床经历了4个成矿阶段:Ⅰ.石英-钾长石;Ⅱ.石英-辉钼矿;Ⅲ.石英-多金属硫化物;Ⅳ.石英-萤石-方解石.包裹体的岩相学及激光拉曼研究揭示,石英斑晶内的熔体-流体包裹体中熔体成分有更长石和钠长石,为岩浆出溶作用形成;子矿物多相包裹体(S型)中含有钾盐、石盐、赤铁矿和石膏等子矿物,显示出成矿流体为高氧逸度.第Ⅰ成矿阶段包裹体有气液两相(L+V型)、富CO2三相(C型)和含石盐、钾盐、赤铁矿及硬石膏等子矿物的多相(S型)等类型,第Ⅱ成矿阶段除了有L+V型、C型以及含钾盐、石盐、黄铜矿和辉钼矿等子矿物多相(S型)外,还可以见到S型包裹体与气相包裹体(V型)共存;第Ⅲ成矿阶段以L+V型和含方解石的S型包裹体为主;第Ⅳ成矿阶段除见到L+V型包裹体外,还可以见到液相包裹体(L型).显微测温结果显示从早到晚,流体包裹体均一温度从530℃变为120℃、盐度从66.7%NaCl equiv变为1.2%NaCl equiv,呈现逐渐降低的趋势.群体包裹体成分显示各阶段均含有气相CO2,液相成分中Na+,K+,Ca2+,SO42-,Cl-含量很高,而F-含量极少.成矿流体总体属于富含CO2的高盐度、高氧逸度的NaCl-H2O-CO2体系,在流体演化过程中温度、氧逸度、盐度和CO2含量逐渐降低.温度、盐度、CO2含量逐渐降低及绢云母化影响了矿石沉淀.
The ultra-large porphyry-type molybdenum deposit at the fork is located in the northern section of the Greater Hinggan Mountains and is characterized by reticulate and brecciated mineralization. The deposit undergoes four stages of mineralization: Ⅰ. Quartz-K-feldspar; Ⅱ. Quartz- Molybdenite, quartz, polymetallic sulphides, quartz, fluorite, and calcite.The petrographic and laser Raman studies of inclusions reveal that the melt composition in the melt-fluid inclusions in the quartz porphyritic There are longer feldspar and albite for the formation of magmatic dissolution. The multi-phase inclusions (S-type) of sub-minerals contain the sub-minerals of potassium salt, rock salt, hematite and gypsum and show that the ore-forming fluid is hyperoxia Fugacity. In the first stage of ore-forming, the inclusions are heterogeneous in gas-liquid two-phase (L + V) and CO2-rich three phases (C type) and with sub-minerals such as rock salt, potassium salt, hematite and anhydrite (S type) and other types, the second stage of mineralization in addition to L + V type, C type and potassium salt, rock salt, chalcopyrite and molybdenite and other mineral multi-phase (S type) To S-type inclusions coexist with gas-phase inclusions (V-type). In the stage Ⅲ ore-forming stage, L + V type and S-type inclusions containing calcite are dominant. In the Ⅳ ore-forming stage, besides L + V type inclusions , You can also see the liquid inclusions (L type). Microscopic The results of temperature measurement show that from early to late, the homogenization temperature of fluid inclusions changes from 530 ℃ to 120 ℃, and the salinity changes from 66.7% NaCl equiv to 1.2% NaCl equiv, showing a decreasing trend gradually. Containing CO2, the content of Na +, K +, Ca2 +, SO42- and Cl- in the liquid phase is very high, while the amount of F- is very little.The ore-forming fluid belongs to the high salinity and high oxygen fugacity rich in CO2, H2O-CO2 system, the temperature, oxygen fugacity, salinity and CO2 content decreased gradually during fluid evolution, and the temperature, salinity and CO2 content gradually decreased and the sericitization affected the ore deposit.