【作者】 刘莉；

【导师】 杨言辰；

【作者基本信息】 吉林大学 ， 地质工程， 2010， 硕士

【摘要】 砍椽沟钼铜矿床位于佳木斯隆起带南缘、八面通隆起的穆棱凹陷和伊林凹陷复合部位,地处佳木斯—牡丹江多金属成矿带的南东段。矿区出露地层主要为中元古界黑龙江群下亚群绿片岩系、中生界花岗质角砾岩及第三系船底山玄武岩。矿区发育岩浆岩主要有花岗岩类和第三纪玄武岩。与成矿有关的是花岗质岩石,主要是花岗闪长岩、花岗闪长斑岩、角砾状花岗斑岩。多处见到晚期石英脉,亦有矿化痕迹。花岗岩带在矿区沿光复屯背斜轴部侵入。北西向的砍椽沟断裂及其次级断裂构造为岩浆活动和矿化作用的中心。本文在原有矿点检查及矿产普查的基础上,深入研究该矿床的矿床成矿背景、矿床地质特征、地球化学特征基础上,分析成矿地质条件,特别是成矿作用与黑龙江群绿色片岩系及中生代花岗质岩浆岩之间的时空关系以及物质成因联系,查明Cu-Mo矿体在时间上、空间上的分布规律及矿体空间组合特征,确定找矿方向,进行找矿远景评价分析,研究成果对指导矿床深部及外围预测具有重要的理论及实际意义。更多还原

【Abstract】 Kanchuangou Mo-Cu deposit which besides to the Dunhua-Mishan deep fault, belongs to the south-east part of Jiamusi-Mudanjiang polymetallic metallogenic belt. The main exposure strata in this area are greenschist series subsets of mesoproterozoic Heilongjiang group, Mesozoic granitic breccia, and tertiary Chuandishan basalt. Among them the granitic rocks are related to metallogenic, and most are granitic diorite, granitic diorite porphyry, breccia granitic-porphyry. Late quartz veins have be seen most place, and also have mineralization traces. The granite belt intruded along the anticline axis in Guangfutun. The North West Kanchuangou fractures and the secondary fracture tectonics are the centre of magmatism and mineralization. Metallogenic granitic diorite and granitic-porphyry present medium-fine grained and unequal grained granitoid texture, massive structure. The main mineral compositions are quartz, alkali feldspar, plagioclass, biotite and some opaque mineral. To analysis the major element content property in metallogenic granitic diorite and granitic-porphyry, it shows that the metallogenic rocks has high Sr, Na, K and low Y, Mg, and have the characteristics of calcium-alkaline magmatic evolution, which belong to the C type adak rock. The test results of trace element show that the granitic rock in this area are lack of Nb, Nd, and such HFS elements, rich of Rb, Ba and such of lithophile elements. It also shows that the granitic rock in this area have the adak rock characteristics. Ree composition has lightly negative Eu anomalies, which shows that plagipclase has some degree fractional crystallization, or had affected by the plagipclase fractional crystallization, and magma is the crust source, and the magma source area exist a certain of garnet residue. The rock alteration show potassic alteration, silicfication, clay alteration, sericitization, chloritization, carbonation and so on.The lindgrenite alteration generally appeared molybdenite, chalcopyrite, and granite cracks filled with a few pyrrhotite, pyrite, metal sulfides, or such minerals distributed sparsely impregnation in the granitite diorite porphyry. According to the mineralization characteristics three kinds of mineralization could be divided, such as veinlet disseminated mineralization, disseminated mineralization, and mineralization associated with quartz vein. The orebody mainly produced in granite belts which are controlled by the fault structures. In the granite belt there developed tectogenetic breccia granite-porphyry, and unequal scale quartz vein. The limit between orebody and surrounding rock isn’t clear, and the limit mainly be delineated by the sample analysis results, which mainly manifested as granodiorite and granite-porphyry locally total mineralization. Minerals as molybdenite and chalcopyrite mainly are hosted in silicification, potassic alteration, carbonation, or such alteration area. And the silicification intensity is related to the mineralize intensity. The orebodys are veiny, strike 35°~50°, and rake angles are in medium scale. The metallic minerals in ore mainly are molybdenite, chalcopyrite and pyrrhottie, with a few sphalerite and galena. The ore structures mainly are sparse disseminated structure and fine vein structure. Based on the laboratory study and the field study, the mineralization stages could be divided into quartz vein (sparse sulfide) filling stage, porphyry type molybdenum mineralization stage, and copper polymetallic mineralization stage. The main mineralization happened in Yanshan late stage(111.8±1.4 Ma). Formation of lindgrenite mainly happened in the last two stages.Research of fluid inclusion show that Kanchuangou lindgrenite ore-forming fluid in a kind of NaCl-H2O system fluid. Before mineralization, the fluid has high temperature and high salinity, which represented the early magma hydrothermal evolution character. At the mineralization phase, the fluid has middle-low temperature and middle-low salinity. The Kuanyuan ditch lindgrenite mineralization period fluid homogeneous temperature zone mainly concentrated in 119.8~276.1℃. The peak 170~200℃exist the trend of temperature reducing and salinity increasing. That show the ore-forming fluid mainly originated from magma period later hydrothermal.The cathodoluminescence photo show that zircon in this area normally are half euhedral to euhedral, particle sizes are 200-250μm, long columnar, oscillatory zones are obviously, breadth large, declared zircons are magmatic origin, formed temperature was high, microelement diffused fast. The dating results show that metallogenic granitic formed age was 111.8±1.4Ma, belong to Mesozoic Yanshan late magma activity product. It indicates the molybdenum deposit formed in Yanshan late period.Based on the geochemistry characteristics of ore contained magmatic, combined with the characteristics of deposit geology, the formation of aspects of ore body is controlled by the granodiorite, granite-porphyry, and the north north-east fault structure, belong to porphyry type hydrothermal vein type cause.Based on the mineralization enrichment regularity, the Kanchuangou lindgrenite belong to porphyry type hydrothermal vein type deposit. The orebody obviously controlled by structure. Metallogenic condition is good, and has large prospecting potential. Especially the underground blind orebody should increase the exploration degree. Geochemical anomaly and deposit geology characteristics show that the mining area has more possibility of concealed orebody. Based on existing exploration results, 4,5,6,7 orebody in inclined shaft engineering system showed north east distribution, trend is about 45°, 1~3 orebody showed north north-east distribution, trend is about 20°. Orebody morphology and scale is controlled by the structure. Rock fragmented and silicification developed area mineralization is stronger. Based on regional structure characteristics and mining area structure development, the working emphasis should be 4,5,6,7 orebody. Through further engineering control, certain scale of commercial reserves could obtain hopefully.更多还原