【摘要】：宋家溝金礦床位于山東省煙臺市牟平區(qū),地處華北與揚子兩大板塊的碰撞構(gòu)造帶,沂沭斷裂帶以東,膠萊盆地東北緣與膠北隆起的構(gòu)造結(jié)合部位,是牟平—乳山成礦帶內(nèi)受密集裂隙帶控制的大型金礦床。中生代晚期,膠東地區(qū)動力學(xué)環(huán)境由NW-SE向的擠壓轉(zhuǎn)變?yōu)镹W-SE向的伸展體制,膠東東部地區(qū)進入重要的成礦期。區(qū)域出露地層主要為前寒武紀地層、中生代地層及新生代第四紀地層。區(qū)內(nèi)巖漿巖較發(fā)育,主要為中生代鵲山弱片麻狀細中粒含石榴二長花崗巖及閃長玢巖、閃長巖和煌斑巖等脈巖。對礦區(qū)內(nèi)煌斑巖進行鋯石U-Pb定年分析,確定成巖年齡為164.2+4.9Ma。區(qū)內(nèi)構(gòu)造發(fā)育,宋家溝金礦床礦體受張性陡傾斷裂和密集裂隙帶聯(lián)合控制,張性斷裂及密集裂隙帶為區(qū)內(nèi)主要的容礦和控礦構(gòu)造。目前礦區(qū)內(nèi)共圈定了35個工業(yè)礦體。礦體形態(tài)主要呈不規(guī)則脈狀,整體走向為北東向,傾向南東,傾角為傾角多為75°-87°,局部較緩為35°-50°,礦體規(guī)模較小。礦石內(nèi)金屬礦物主要有銀金礦、自然金和黃鐵礦,其次為少量黃銅礦、閃鋅礦、方鉛礦和磁鐵礦等；礦石結(jié)構(gòu)以自形-半自形粒狀結(jié)構(gòu)、碎裂結(jié)構(gòu)和填隙結(jié)構(gòu)為主；礦石構(gòu)造以致密塊狀、團塊狀、脈狀、浸染狀和角礫狀構(gòu)造為主。圍巖蝕變類型主要有黃鐵絹英巖化、硅化、鉀化和碳酸鹽化等,其中黃鐵絹英巖化和硅化與金礦化關(guān)系密切。宋家溝金礦的熱液成礦期可劃分為四個成礦階段：石英—黃鐵礦階段(Ⅰ)、石英—絹云母—黃鐵礦階段(Ⅱ)、金—石英—多金屬硫化物階段(Ⅲ)和碳酸巖階段(Ⅳ),其中第Ⅱ與第Ⅲ階段為主成礦階段。流體包裹體研究表明,宋家溝金礦床成礦流體為CO2-H2O-NaCl體系；成礦流體具有低鹽度(5.0～12.0wt%NaCleqv)、低密度(0.64～0.96g/cm3)的特點。成礦溫度集中在200～2400C之間,成礦壓力區(qū)間為40～62MPa,成礦深度為5.01～6.34km。氫、氧同位素測試結(jié)果表明,成礦流體來自幔源初生水,并有后期大氣降水的加入；硫同位素研究表明,硫主要來自地幔,并與荊山群有一定的繼承性；鉛同位素研究結(jié)果表現(xiàn)出深源特征。綜上所述,確定宋家溝金礦床成因類型為幔源流體參與成礦的中溫?zé)嵋好}型金礦床。宋家溝金礦床礦體受早白堊紀萊陽群內(nèi)發(fā)育的張性陡傾斷裂和密集裂隙帶聯(lián)合控制；工業(yè)礦體有明顯的分段富集現(xiàn)象,主要富集在斷裂走向偏NE的位置,而在走向偏NEE的位置礦化明顯減弱；傾向上礦體主要富集在傾角由緩變陡的位置；控礦斷裂構(gòu)造在成礦期顯示左旋正斷的性質(zhì)。礦體側(cè)伏規(guī)律不明顯,局部有向北東側(cè)伏的趨勢,側(cè)伏角為30°～50°。認為膠萊盆地東北緣剝蝕程度從西向東逐漸減小,宋家溝金礦區(qū)為剝蝕程度最小的礦區(qū)；在綜合分析礦化富集規(guī)律和該區(qū)剝蝕保存條件的基礎(chǔ)上,認為宋家溝金礦區(qū)深部及外圍具有一定的找礦潛力。
[Abstract]:The Songjiagou gold deposit is located in Muping District, Yantai City, Shandong Province. It is located in the collision tectonic belt of North China and Yangtze plates, east of Yishu fault zone, and the structural combination site between northeast margin of Jiaolai Basin and Jiaobei uplift. It is a large gold deposit controlled by dense fracture zone in Muping-Rushan metallogenic belt. In the late Mesozoic, the dynamic environment in Jiaodong area changed from NW-SE to compression to NW-SE extensional system, and the eastern Jiaodong area entered an important metallogenic period. The regional outcrop strata are mainly Precambrian, Mesozoic and Cenozoic Quaternary strata. The magmatic rocks in the area are relatively developed, mainly composed of granitic granites, diorite porphyrite, diorite and lamprophyre, etc. Zircon U-Pb dating analysis of lamprophyres in the mining area shows that the diagenetic age is 164.2. 9 Ma. The orebody of the Songjiagou gold deposit is controlled by tensional steep-dip faults and dense fissures, and the tensional faults and dense fissures are the main ore-holding and ore-controlling structures in the area. At present, 35 industrial orebodies have been delineated in the mining area. The shape of the orebody is mainly irregular vein, the whole strike is north-east, the inclination angle is 75 擄-87 擄, the local degree is 35 擄-50 擄, and the scale of orebody is small. The ore is mainly composed of silver gold, natural gold and pyrite, followed by a small amount of chalcopyrite, sphalerite, galena and magnetite, etc. The ore structures are compact, massive, veined, disseminated and breccia. The main alteration types of surrounding rock are yellow sericite, silicification, kalitization and carbonization, among which the yellowtigitization and silicification are closely related to gold mineralization. The hydrothermal metallogenic stage of Songjiagou gold deposit can be divided into four metallogenic stages: quartz pyrite stage (鈪，

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