發(fā)布時間：2019-06-15 13:42

【摘要】：膠東半島位于華北地塊與揚子地塊的疊合部位，半島內(nèi)金礦眾多，儲量巨大，構(gòu)成了我國最重要的金礦產(chǎn)地，已探明的資源量和黃金產(chǎn)量均居全國之首。山后金礦位于膠東半島金礦密集區(qū)的西北部招平斷裂構(gòu)造帶上、南距萊西市34km、北據(jù)招遠市30km。中生代早-中期，古太平洋板塊向歐亞板塊由SE向NW斜向快速俯沖，膠東地區(qū)進入重要的碰撞造山階段。 山后金礦區(qū)內(nèi)出露地層為太古代膠東群和元古代荊山群地層，其中，膠東群位于礦區(qū)北東部，巖性主要為黑云角閃斜長變粒巖、黑云斜長片麻巖；荊山群地層主要巖性為大理巖。礦區(qū)內(nèi)巖漿巖分布廣泛，主要為中粗粒黑云母二長花崗巖和片麻狀黑云母花崗巖，前人認為這兩種巖性為元古代的巖漿巖，本文對其進行鋯石U-Pb定年分析，結(jié)果顯示，成巖年齡分別為148.8±1.5Ma和144.1±1.2Ma，均為晚侏羅世。礦區(qū)內(nèi)發(fā)育閃長玢巖及煌斑巖等中生代脈巖。礦區(qū)內(nèi)斷裂構(gòu)造十分發(fā)育，形成較早的是近EW向的黑虎山斷裂，規(guī)模最大的是NE向的招平斷裂帶。其中，招平斷裂帶是本區(qū)的主要控礦構(gòu)造，礦體多產(chǎn)于其主斷面下盤。 目前礦區(qū)內(nèi)共圈定了16個工業(yè)礦體， I-2為礦區(qū)內(nèi)主要礦體，，形態(tài)多呈脈狀、透鏡狀、板柱狀，礦體產(chǎn)狀穩(wěn)定，走向30°～33°；傾向SE,傾角26°～46°。礦體走向長75m～349m；礦體厚0.53m～17.00m。山后金礦的礦石量1641012t，金屬量為7584kg，金平均品位4.62×10-6。礦石類型主要為黃鐵絹英巖型和黃鐵絹英巖化花崗質(zhì)碎裂巖型，礦石的結(jié)構(gòu)主要為填隙結(jié)構(gòu)、固溶體分離結(jié)構(gòu)、壓碎結(jié)構(gòu)和交代結(jié)構(gòu)等；礦石的構(gòu)造主要為脈狀構(gòu)造、網(wǎng)脈狀構(gòu)造及細脈浸染狀構(gòu)造。礦區(qū)內(nèi)圍巖蝕變的主要類型為鉀化、絹云母化、硅化、黃鐵絹英巖化、綠泥石化和碳酸鹽化等，其中黃鐵絹英巖化和硅化與金礦化的關(guān)系最為密切，也是本區(qū)重要的找礦標志。山后金礦經(jīng)歷了熱液期和表生氧化期兩個成礦時期，熱液成礦期分為4個成礦階段：Ⅰ黃鐵礦-石英（鉀化）階段、Ⅱ石英-黃鐵礦（絹英巖化）階段、Ⅲ金-石英-多金屬硫化物階段、Ⅳ石英-碳酸鹽階段，主成礦階段為Ⅱ、Ⅲ階段。 流體包裹體研究及激光拉曼光譜分析結(jié)果顯示，成礦流體為富含CO2的低鹽度（8～10wt%NaCl.eqv）、低密度（0.85～0.89g/cm3）的NaCl-H2O-CO2體系，礦溫度為230~290℃，成礦壓力為80~101MPa，成礦深度7.09-8.61km。氫、氧同位素研究顯示，成礦流體以幔源流體為主，并有少量的巖漿水和大氣降水的加入；硫同位素研究表明，成礦物質(zhì)來自于上地幔。綜上確定山后金礦床的成因類型為幔源流體參與成礦的中溫熱液脈型金礦床。 山后金礦的工業(yè)礦體嚴格受NE向的招平斷裂帶控制，由于斷層泥對含礦熱液的屏蔽作用，導致礦體均產(chǎn)于主斷裂面下盤；礦體富集的部位多在斷裂走向上偏東、傾角由陡變緩的位置；工業(yè)礦體在水平和垂向上均具有明顯的分段富集。經(jīng)分析認為，成礦期招平斷裂帶表現(xiàn)為右旋逆斷活動特點，工業(yè)礦體具有明顯的向NE側(cè)伏的規(guī)律，側(cè)伏角約75°，結(jié)合分析研究控礦構(gòu)造的空間變化規(guī)律、分段富集規(guī)律、側(cè)伏規(guī)律和工業(yè)礦體的空間定位機制等礦化富集規(guī)律的基礎上，初步認為山后金礦區(qū)在深部存在另一個礦化富集段，也是下一步找礦的重點。
[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 擄, the inclination is SE, and the inclination angle is 26 擄 ~ 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

本文編號：2500256