山东莱西山后金矿床地质特征及矿化富集规律
发布时间：2019-06-15 13:42
【摘要】：胶东半岛位于华北地块与扬子地块的叠合部位，半岛内金矿众多，储量巨大，构成了我国最重要的金矿产地，已探明的资源量和黄金产量均居全国之首。山后金矿位于胶东半岛金矿密集区的西北部招平断裂构造带上、南距莱西市34km、北据招远市30km。中生代早-中期，古太平洋板块向欧亚板块由SE向NW斜向快速俯冲，胶东地区进入重要的碰撞造山阶段。 山后金矿区内出露地层为太古代胶东群和元古代荆山群地层，其中，胶东群位于矿区北东部，岩性主要为黑云角闪斜长变粒岩、黑云斜长片麻岩；荆山群地层主要岩性为大理岩。矿区内岩浆岩分布广泛，主要为中粗粒黑云母二长花岗岩和片麻状黑云母花岗岩，前人认为这两种岩性为元古代的岩浆岩，本文对其进行锆石U-Pb定年分析，结果显示，成岩年龄分别为148.8±1.5Ma和144.1±1.2Ma，均为晚侏罗世。矿区内发育闪长玢岩及煌斑岩等中生代脉岩。矿区内断裂构造十分发育，形成较早的是近EW向的黑虎山断裂，规模最大的是NE向的招平断裂带。其中，招平断裂带是本区的主要控矿构造，矿体多产于其主断面下盘。 目前矿区内共圈定了16个工业矿体， I-2为矿区内主要矿体，，形态多呈脉状、透镜状、板柱状，矿体产状稳定，走向30°～33°；倾向SE,倾角26°～46°。矿体走向长75m～349m；矿体厚0.53m～17.00m。山后金矿的矿石量1641012t，金属量为7584kg，金平均品位4.62×10-6。矿石类型主要为黄铁绢英岩型和黄铁绢英岩化花岗质碎裂岩型，矿石的结构主要为填隙结构、固溶体分离结构、压碎结构和交代结构等；矿石的构造主要为脉状构造、网脉状构造及细脉浸染状构造。矿区内围岩蚀变的主要类型为钾化、绢云母化、硅化、黄铁绢英岩化、绿泥石化和碳酸盐化等，其中黄铁绢英岩化和硅化与金矿化的关系最为密切，也是本区重要的找矿标志。山后金矿经历了热液期和表生氧化期两个成矿时期，热液成矿期分为4个成矿阶段：Ⅰ黄铁矿-石英（钾化）阶段、Ⅱ石英-黄铁矿（绢英岩化）阶段、Ⅲ金-石英-多金属硫化物阶段、Ⅳ石英-碳酸盐阶段，主成矿阶段为Ⅱ、Ⅲ阶段。 流体包裹体研究及激光拉曼光谱分析结果显示，成矿流体为富含CO2的低盐度（8～10wt%NaCl.eqv）、低密度（0.85～0.89g/cm3）的NaCl-H2O-CO2体系，矿温度为230~290℃，成矿压力为80~101MPa，成矿深度7.09-8.61km。氢、氧同位素研究显示，成矿流体以幔源流体为主，并有少量的岩浆水和大气降水的加入；硫同位素研究表明，成矿物质来自于上地幔。综上确定山后金矿床的成因类型为幔源流体参与成矿的中温热液脉型金矿床。 山后金矿的工业矿体严格受NE向的招平断裂带控制，由于断层泥对含矿热液的屏蔽作用，导致矿体均产于主断裂面下盘；矿体富集的部位多在断裂走向上偏东、倾角由陡变缓的位置；工业矿体在水平和垂向上均具有明显的分段富集。经分析认为，成矿期招平断裂带表现为右旋逆断活动特点，工业矿体具有明显的向NE侧伏的规律，侧伏角约75°，结合分析研究控矿构造的空间变化规律、分段富集规律、侧伏规律和工业矿体的空间定位机制等矿化富集规律的基础上，初步认为山后金矿区在深部存在另一个矿化富集段，也是下一步找矿的重点。
[Abstract]:The Jiaodong Peninsula is located in the overlapping part of the North China block and the Yangtze block, and the gold deposits in the peninsula are large and the reserves are huge, which constitute the most important gold mining area in our country, and the proven resource and gold production are the highest in the whole country. The post-mountain gold deposit is located in the north-west of the concentrated area of the Jiaodong Peninsula gold deposit, with a belt of 34km from the city of Laxi and 30 km from the north. In the early-mid-term of the Mesozoic, the paleo-Pacific plate was subducted to the Eurasian plate from the SE to the NW, and the Jiaodong area entered the important collision orogeny stage. The outcrop formation in the post-mountain gold deposit is the formation of the ancient Jiaodong Group and the Proterozoic Jingshan Group, among which, the Jiaodong Group is located in the eastern part of the mining area, and the lithology is mainly of the black-cloud hornblende-granulite and the black-cloud inclined-long gneiss, and the main lithology of the Jingshan Group is Dali. The rock and magmatic rock in the mining area is widely distributed, mainly of medium-coarse-coarse-coarse-grained biotite-2-long granite and sheet-shaped biotite-like granite. The two kinds of lithologies are considered to be the rock-magmatic rocks of the Proterozoic. The results show that the diagenetic age is 148.8-1.5Ma and 144.1-1.2m, respectively. A. Both are the Late Jurassic. The Mesozoic veins, such as the granodiorite and the granophyre in the mining area. The fault structure in the mining area is very developed, and the formation of the early is the fault of the Black Tiger Mountain in the near EW direction, and the largest scale is the flat fracture of the NE direction. The Zhaoping fault zone is the main ore-controlling structure in this area, and the ore body is more of its main section. In the present mining area,16 industrial ore bodies are delineated, and I-2 is the main ore body in the mining area. The form is mostly vein-like, lenticular, plate-shaped, the occurrence of the ore body is stable, the trend is 30-33 掳, the inclination is SE, and the inclination angle is 26 掳 ~ The ore body has a length of 75m-349m, and the thickness of the ore body is 0.53 m ~ 17. 00 m. The amount of ore in the post-mountain gold mine is 1641012t, the metal quantity is 7584 kg, and the average grade of gold is 4.62%. 0-6. The ore type is mainly of the yellow-iron-sericite type and the yellow-iron-sericite-type rock type, and the structure of the ore is mainly the interstitial structure, the solid solution separation structure, the crushing structure and the metasomatic structure, etc. The structure of the ore is mainly the vein-like structure, the net-vein-like structure and the fine-vein impregnation. The main types of the alteration of the surrounding rock in the mining area are potassium, sericite, silicidation, sericite, chlorite and carbonate, among which the relationship between the formation of the sericite and the silicification and the gold mineralization is the most closely related, and it is also an important finding in this area. The ore-forming period is divided into four ore-forming stages: the stage of the pyrite-quartz (potassium) stage, the II-quartz-pyrite (sericite) stage, the 鈪
本文编号：2500256
[Abstract]:The Jiaodong Peninsula is located in the overlapping part of the North China block and the Yangtze block, and the gold deposits in the peninsula are large and the reserves are huge, which constitute the most important gold mining area in our country, and the proven resource and gold production are the highest in the whole country. The post-mountain gold deposit is located in the north-west of the concentrated area of the Jiaodong Peninsula gold deposit, with a belt of 34km from the city of Laxi and 30 km from the north. In the early-mid-term of the Mesozoic, the paleo-Pacific plate was subducted to the Eurasian plate from the SE to the NW, and the Jiaodong area entered the important collision orogeny stage. The outcrop formation in the post-mountain gold deposit is the formation of the ancient Jiaodong Group and the Proterozoic Jingshan Group, among which, the Jiaodong Group is located in the eastern part of the mining area, and the lithology is mainly of the black-cloud hornblende-granulite and the black-cloud inclined-long gneiss, and the main lithology of the Jingshan Group is Dali. The rock and magmatic rock in the mining area is widely distributed, mainly of medium-coarse-coarse-coarse-grained biotite-2-long granite and sheet-shaped biotite-like granite. The two kinds of lithologies are considered to be the rock-magmatic rocks of the Proterozoic. The results show that the diagenetic age is 148.8-1.5Ma and 144.1-1.2m, respectively. A. Both are the Late Jurassic. The Mesozoic veins, such as the granodiorite and the granophyre in the mining area. The fault structure in the mining area is very developed, and the formation of the early is the fault of the Black Tiger Mountain in the near EW direction, and the largest scale is the flat fracture of the NE direction. The Zhaoping fault zone is the main ore-controlling structure in this area, and the ore body is more of its main section. In the present mining area,16 industrial ore bodies are delineated, and I-2 is the main ore body in the mining area. The form is mostly vein-like, lenticular, plate-shaped, the occurrence of the ore body is stable, the trend is 30-33 掳, the inclination is SE, and the inclination angle is 26 掳 ~ The ore body has a length of 75m-349m, and the thickness of the ore body is 0.53 m ~ 17. 00 m. The amount of ore in the post-mountain gold mine is 1641012t, the metal quantity is 7584 kg, and the average grade of gold is 4.62%. 0-6. The ore type is mainly of the yellow-iron-sericite type and the yellow-iron-sericite-type rock type, and the structure of the ore is mainly the interstitial structure, the solid solution separation structure, the crushing structure and the metasomatic structure, etc. The structure of the ore is mainly the vein-like structure, the net-vein-like structure and the fine-vein impregnation. The main types of the alteration of the surrounding rock in the mining area are potassium, sericite, silicidation, sericite, chlorite and carbonate, among which the relationship between the formation of the sericite and the silicification and the gold mineralization is the most closely related, and it is also an important finding in this area. The ore-forming period is divided into four ore-forming stages: the stage of the pyrite-quartz (potassium) stage, the II-quartz-pyrite (sericite) stage, the 鈪
本文编号：2500256
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