發(fā)布時間：2018-07-28 19:57

【摘要】：黔西南地跨揚子陸塊和華南褶皺系的右江造山帶兩個大地構(gòu)造單元,從更廣義的角度來說,研究區(qū)毗鄰環(huán)太平洋構(gòu)造域與特提斯構(gòu)造域的結(jié)合部位。黔西南眾多金礦床屬于典型的微細(xì)浸染型金礦床,以地質(zhì)構(gòu)造為首要控礦因素,所以從地質(zhì)構(gòu)造的角度對金礦的成礦模式進(jìn)行討論就顯得恰得其分。本次論文選擇了研究區(qū)幾個典型金礦床(水銀洞金礦、爛泥溝金礦、丫他金礦和戈塘金礦)為切入點,在了解區(qū)域地質(zhì)特征、地質(zhì)構(gòu)造演化、礦區(qū)地質(zhì)特征和礦體地質(zhì)特征的基礎(chǔ)上,結(jié)合礦相學(xué)分析、流體包裹體分析以及同位素分析等技術(shù)手段,同時,歸納比較前人研究成果,從而對區(qū)域地質(zhì)構(gòu)造演化與區(qū)域金礦成礦作用進(jìn)行討論研究。從大地構(gòu)造劃分的角度,除戈塘和水銀洞等少數(shù)金礦床產(chǎn)于揚子陸塊西南緣(毗鄰右江造山帶),幾乎所有黔西南微細(xì)浸染型金礦都產(chǎn)于右江造山帶,反映黔西南微細(xì)浸染型金礦床的形成與右江盆地之間存在某種必然的聯(lián)系。此外,黔西南各微細(xì)浸染型金礦床有著極相似的礦化蝕變特征與成礦理化條件,反映了這些金礦床成礦過程中成礦流體與物質(zhì)的同源性,以及成礦過程中相同的動力學(xué)背景。黔西南金礦床賦礦層位主要有上二疊統(tǒng)龍?zhí)督M(P_3l)、上二疊統(tǒng)龍?zhí)督M(P_3l)和中二疊統(tǒng)茅口組(P_2m)之間的構(gòu)造蝕變體(Sbt)(形成于區(qū)域性構(gòu)造活動)、中三疊統(tǒng)邊陽組(T_2by)和中三疊統(tǒng)許滿組(T_2xm)中。其中賦礦于二疊統(tǒng)龍?zhí)督M和構(gòu)造蝕變體的有水銀洞金礦床、戈塘金礦床;賦礦于中三疊統(tǒng)許滿組和邊陽組的有爛泥溝金礦和丫他金礦(以許滿組為主)。水銀洞、丫他以及戈塘金礦床的流體包裹體分析測試得出,成礦流體溫度范圍為100~293.3℃,鹽度范圍為0.18~13.62wt%,密度范圍為0.75~1.06g/cm~3,成礦壓力范圍為178.51~731.73×10~5Pa,表明黔西南金礦床是典型的中低溫?zé)嵋航鸬V床。此外,綜合對比前人研究,成礦流體還具富CO_2和CH_4、偏還原、弱酸性和低氧逸度等特點。微細(xì)浸染型金礦具典型的構(gòu)造控礦特征,從構(gòu)造演化的角度出發(fā),黔西南微細(xì)浸染型金礦與右江盆地的裂解、碰撞造山及后碰撞側(cè)向擠壓存在必然的、十分密切的聯(lián)系,含礦流體的產(chǎn)生和匯聚皆與右江盆地的形成和碰撞過程密切相關(guān),而含礦熱液中礦質(zhì)在后碰撞造山側(cè)向擠壓階段發(fā)生沉淀作用而富集成礦。綜合黔西南地區(qū)地質(zhì)構(gòu)造演化與金礦成礦的特點,黔西南微細(xì)浸染型金礦的成礦經(jīng)歷了三個階段:中泥盆世—早三疊世,右江盆地裂解-弧后盆地階段,形成含礦建造;中三疊世—中侏羅世,右江盆地前陸盆地階段,初步形成含礦流體;晚侏羅世—早白堊世,右江盆地碰撞造山側(cè)向擠壓階段:成礦物質(zhì)的富集成礦。
[Abstract]:There are two geotectonic units, the Yangtze block and the Youjiang orogenic belt of the South China fold system in southwest Guizhou. In a more general sense, the study area is adjacent to the conjunctions of the circum-Pacific tectonic domain and the Tethys tectonic domain. Many gold deposits in southwestern Guizhou are typical micro-disseminated gold deposits, and the geological structure is the primary ore-controlling factor, so it is obvious that the metallogenic model of gold deposits can be discussed from the perspective of geological structure. In this paper, several typical gold deposits (Shuiyindong gold deposit, Luanjigou gold deposit, Yata gold deposit and Gotang gold deposit) are selected as the entry point to understand the regional geological characteristics and tectonic evolution. On the basis of geological characteristics of mining area and orebody, combined with the technical means of mineralogical analysis, fluid inclusion analysis and isotope analysis, and at the same time, the previous research results are summarized and compared. The evolution of regional geological structure and mineralization of regional gold deposits are discussed. From the perspective of tectonic division, a few gold deposits, such as Gegotang and Shuiyindong, occur in the southwestern margin of the Yangtze block (adjacent to the Youjiang orogenic belt), and almost all micro-disseminated gold deposits in southwest Guizhou are located in the Youjiang orogenic belt. It shows that there is an inevitable relationship between the formation of microdisseminated gold deposits in southwest Guizhou and the Youjiang basin. In addition, the microdisseminated gold deposits in southwest Guizhou have very similar mineralization alteration characteristics and metallogenic physicochemical conditions, which reflect the homology of ore-forming fluid and material and the same dynamic background in the metallogenic process of these gold deposits. The ore-bearing strata of the gold deposit in southwest Guizhou mainly include the Upper Permian Longtan formation (PSP 31), the Upper Permian Longtan formation (P 31 1) and the Middle Permian Maokou formation (P Permian), the tectonic alteration (Sbt) (formed in the regional tectonic activity), the Middle Triassic Bian Yang formation (T_2by) and the Middle Triassic Xuman formation (T_2xm). Among them, there are Shuiyindong gold deposit and Gotang gold deposit in Longtan formation and tectonic alteration of Permian and Luannigou gold deposit and Yata gold deposit in the middle Triassic Xuman formation and Bian Yang formation (mainly Xuman formation). The fluid inclusions of the Mercury Cave, Yatta and Gotang gold deposits show that the ore-forming fluid temperature ranges from 100 to 293.3 鈩，

本文編號：2151415