【摘要】：二道河子鉛鋅礦位于額爾古納地塊與興安地塊的結(jié)合部位,得耳布干斷裂北西側(cè),大興安嶺得耳布干成礦帶中部上護(hù)林-西吉諾成礦亞帶內(nèi)。該帶成礦地質(zhì)條件優(yōu)越,礦產(chǎn)資源豐富,現(xiàn)己發(fā)現(xiàn)多處大中型鉛鋅礦床。礦區(qū)出露的地層主要為中侏羅統(tǒng)塔木蘭溝組火山巖地層和第四系殘坡積物、沖洪積物�；鹕綆r地層產(chǎn)狀平緩,主要由有安山巖、流紋巖、晶屑凝灰?guī)r、凝灰?guī)r、沉凝灰以及火山角礫巖組成,此外還發(fā)育有熔結(jié)的巖屑晶屑凝灰?guī)r、砂巖和礫巖等。區(qū)域NE向得耳布干深斷裂從礦區(qū)東南部通過,其次級構(gòu)斷裂構(gòu)成礦區(qū)的主要構(gòu)造格局,其中北西向斷裂發(fā)育密集,在礦區(qū)內(nèi)形成三條斷裂破碎帶,控制了鉛鋅礦體的產(chǎn)出,北東向斷裂對礦體有一定的破壞作用,斷裂均具有多期活動(dòng)的特征。礦床主要由三個(gè)礦帶構(gòu)成,礦體主要呈脈狀、網(wǎng)脈狀、透鏡狀產(chǎn)出于塔木蘭溝組晶屑凝灰?guī)r、安山巖的北西向斷裂破碎帶中。礦體形態(tài)嚴(yán)格受控于斷裂構(gòu)造,產(chǎn)狀穩(wěn)定,局部具有膨大收縮的特征,斷裂交匯處礦體厚大。二道河子鉛鋅礦床的主要金屬礦物有方鉛礦、閃鋅礦、黃鐵礦、黃銅礦等,而脈石礦物主要有石英、方解石、絹云母、綠泥石等。交代溶蝕結(jié)構(gòu)、半自形粒狀結(jié)構(gòu)、固溶體分離結(jié)構(gòu)等是二道河子鉛鋅礦主要的礦石結(jié)構(gòu),礦石構(gòu)造主要有脈狀-網(wǎng)脈狀構(gòu)造、浸染狀構(gòu)造、塊狀構(gòu)造等。圍巖蝕變主要有硅化、絹云母化、碳酸鹽化、綠泥石化等,其中硅化與鉛鋅礦化較為密切。成礦過程可劃分為熱液期與表生期,其中熱液期又可劃分為石英一黃鐵礦階段、石英一多金屬硫化物階段與石英-碳酸鹽階段。地球化學(xué)研究表明,礦區(qū)安山巖可分為堿性系列和高鉀鈣堿性系列,流紋巖和火山碎屑巖屬于高鉀鈣堿性系列,而脈巖多屬鉀玄巖系列。礦區(qū)火山巖輕、重稀土分異明顯,強(qiáng)烈富集大離子親石元素,虧損高場強(qiáng)元素,結(jié)合前人同位素資料研究表明中酸性火山巖主要來源于地幔,并有地殼物質(zhì)的混染,而酸性火山巖是來源于地殼部分熔融,礦區(qū)火山巖可能形成于大陸板內(nèi)構(gòu)造環(huán)境。二道河子鉛鋅礦床流體包裹體主要有富氣相和富液相兩種類型,石英包裹體均一溫度在77℃~384℃,大至集中在250℃~270℃和310℃~330℃,閃鋅礦的均一溫度為254℃,因此240℃~280℃基本代表主成礦階段溫度范圍。成礦流體總體上為一套中溫、低鹽度、低密度流體,流體壓力在17.85 Mpa~31.15 Mpa,成礦深度為0.66 km~1.15 km。成礦流體具有多期次的特征。流體包裹體成分測試表明成礦流體為CO2-H2O-NaCl體系,并且富含深源氣體,結(jié)合區(qū)域S、Pb、H、O同位素特征,推測成礦物質(zhì)主要來源于深部,成礦流體為巖漿水和大氣降水組成的混合流體。綜合研究認(rèn)為二道河子鉛鋅礦床成因類型為斷裂控制的與火山—次火山熱液有關(guān)的淺成中低溫?zé)嵋盒豌U鋅礦床,形成于燕山晚期大陸板內(nèi)伸展構(gòu)造環(huán)境。
[Abstract]:Erdaohezi lead-zinc deposit is located in the joint part of Erguna block and Xingan block, the north west side of Deerbugan fault, and the upper protection forest- Xijinuo metallogenic subzone in the middle of Daxing'anling Deerbugan metallogenic belt. There are many large and medium-scale lead-zinc deposits found in this belt because of its superior geological conditions and rich mineral resources. The exposed strata of the mining area are the volcanic strata of the middle Jurassic Tamulangou formation and the Quaternary residual slope deposits and alluvial deposits. The volcanic strata are flat, mainly composed of andesite, rhyolite, crystalline tuff, sedimentary tuff and volcanic breccia, in addition, there are clastic tuff, sandstone and conglomerate, etc. The regional NE trending Deerbugan deep fault passes through the southeast of the mining area, and the next gradation fault constitutes the main tectonic pattern of the mining area, in which the NW trending faults are densely developed, and three fracture zones are formed in the mining area, which control the production of the lead-zinc orebody. NNE faults have a certain destructive effect on orebodies, and the faults have the characteristics of multi-stage activity. The ore deposit is mainly composed of three ore belts, the orebody is mainly vein-like and reticulate, and lenticular occurs in the grain tuff of the Tamulangou formation and the NW-trending fracture zone of the andesite. The shape of the orebody is strictly controlled by the fault structure, the occurrence is stable, the part has the characteristic of expanding and shrinking, and the orebody at the fault junction is thick. The main metal minerals of Erdaohezi Pb-Zn deposit are galena sphalerite pyrite chalcopyrite and so on while gangue minerals mainly include quartz calcite sericite chlorite and so on. Metasomatic dissolution structure, semi-automorphic granular structure and solid solution separation structure are the main ore structures of Erdaohezi lead-zinc deposit. The ore structures mainly include vein-reticulate structure, disseminated structure, block structure and so on. The main alteration of surrounding rock is silicification sericite carbonization green mud fossilization and so on among which silicification and lead-zinc mineralization are very close. The metallogenic process can be divided into hydrothermal period and epigenetic stage, in which hydrothermal period can be divided into quartz-pyrite stage, quartz-polymetallic sulfide stage and quartz-carbonate stage. Geochemical studies show that the andesite can be divided into alkaline series and high-potassium calc-alkaline series, rhyolite and pyroclastic rocks belong to high-potassium calc-alkaline series, and dike rocks belong to kaliacite series. The volcanic rocks in the mining area are characterized by light, heavy rare earth elements, strong enrichment of large ion lithophile elements and depletion of high field strength elements. Combined with previous isotopic data, it is shown that the intermediate-acid volcanic rocks are mainly derived from the mantle and are mixed with crustal materials. The acidic volcanic rocks are derived from partial melting of the crust, and the volcanic rocks in the mining area may be formed in the continental intraplate tectonic environment. The fluid inclusions of Erdaohezi lead-zinc deposit are mainly gas-rich and liquid-rich. The homogenization temperature of quartz inclusions is from 77 鈩，

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