本文選題：火山巖 + 構(gòu)造環(huán)境��； 參考：《中國科學(xué)院研究生院(廣州地球化學(xué)研究所)》2016年博士論文

【摘要】：西昆侖造山帶自南向北依次分為喀喇昆侖地體、甜水海地體、南昆侖地體和北昆侖地體。北昆侖地體與塔里木塊體的結(jié)合帶大面積出露一系列晚古生代火山巖,展布于昆蓋山北坡蓋孜-庫地-上期汗一線,從西昆侖山的西部一直綿延至西昆侖山的東部,長達(dá)數(shù)千公里。此晚古生代火山巖帶發(fā)育一系列中小型VMS礦床,阿克塔什銅-金礦床、薩洛依銅礦床為其中最具有代表性的礦床。本文以阿克塔什銅-金礦床和薩洛依銅礦床為研究對(duì)象,在系統(tǒng)的總結(jié)礦床地質(zhì)特征的基礎(chǔ)上,結(jié)合對(duì)賦礦火山巖的研究,深入探討成礦構(gòu)造環(huán)境、成巖成礦時(shí)代、成礦物質(zhì)來源,分析礦床成因類型,建立成礦模式。主要取得了以下認(rèn)識(shí)和成果:1通過對(duì)阿克塔什火山巖、薩洛依玄武巖和蓋孜安山巖的鋯石U-Pb年齡的系統(tǒng)分析得到,西昆侖地區(qū)昆蓋山北坡-蓋孜一帶原劃分為石炭紀(jì)的火山巖,形成時(shí)代應(yīng)該為早二疊世和晚二疊世。阿克塔什火山巖的年齡為284.6Ma,薩洛依玄武巖的年齡為263.0Ma,蓋孜安山巖的年齡為263.8Ma。2阿克塔什火山巖發(fā)育在島弧擴(kuò)張的初期,為一套島弧拉斑性質(zhì)的雙峰式火山巖和鈣堿性玄武巖。蓋孜安山巖和薩洛依玄武巖為相對(duì)晚期的具有N-MORB性質(zhì)島弧玄武巖和島弧安山巖,二者的成巖年齡近乎相同,由此推測(cè)蓋孜安山巖可能與薩洛依玄武巖為同套火山巖。阿克塔什火山巖到薩洛依玄武巖-蓋孜安山巖的巖石地球化學(xué)特征的變化,反映此套火山巖產(chǎn)出的大地構(gòu)造環(huán)境處于島弧向弧間(后)盆地的過渡階段。3通過對(duì)阿克塔什銅-金礦床賦礦圍巖的巖石地球化學(xué)特征的研究,認(rèn)為阿克塔什礦床的賦礦圍巖可以與西太平洋日本沖繩島弧產(chǎn)出的塊狀硫化物礦床的賦礦圍巖相對(duì)比,薩洛依銅礦床的賦礦圍巖為枕狀構(gòu)造的拉斑玄武巖,與塞浦路斯型礦床的圍巖類似。4對(duì)阿克塔什銅-金礦床和薩洛依銅礦床分別進(jìn)行了詳細(xì)的礦床地球化學(xué)(礦石地球化學(xué)、圍巖地球化學(xué)、S同位素)研究,各項(xiàng)證據(jù)均表明阿克塔什銅-金礦床的成礦物質(zhì)主要來源于火山巖,薩洛依銅礦床的成礦物質(zhì)來源于火山巖和海洋沉積物。5通過對(duì)阿克塔什、薩洛依銅礦床中的硫化物主微量元素的分析,礦體從下盤到上盤具有明顯的分帶規(guī)律。據(jù)此將阿克塔什礦床與薩洛依銅礦床的成礦過程分別分為三個(gè)“階段”。阿克塔什銅-金礦床的成礦過程依次為火山噴氣“階段”、火山熱液沉積“階段”、含礦熱鹵水+火山熱液沉積“階段”;薩洛依銅礦床的成礦過程依次為富礦熱鹵水沉積“階段”、熱鹵水沉積+火山熱液沉積“階段”、含礦熱鹵水沉積“階段”。6阿克塔什礦床的硫主要來自于巖漿噴氣作用,薩洛依礦床為多硫源成因,硫可能為海水硫、火山噴氣硫和沉積硫的混合。7同沉積的塊狀硫化物礦床的形成時(shí)代與火山巖的形成時(shí)代一致。所以,阿克塔什銅-金礦床的成礦時(shí)代為早二疊世,薩洛依銅礦床的成礦時(shí)代為晚二疊世。8阿克塔什銅-金礦床中黃鐵礦的Re-Os同位素年齡與圍巖年齡存在一定的差異,本次認(rèn)為黃鐵礦的Re-Os體系可能已不滿足同源性條件,但保留對(duì)黃鐵礦Re-Os年齡的探討。有可能阿克塔什礦床的東礦區(qū)地層為庫地-奧依塔克蛇綠巖套的殘片,對(duì)東礦區(qū)的地層接觸關(guān)系還需要進(jìn)一步研究。9將阿克塔什礦床和薩洛依礦床同典型的塊狀硫化物礦床類型進(jìn)行對(duì)比,二者均為典型的與火山作用相關(guān)的VMS礦床,礦床成因類型分別為別子型塊狀硫化物礦床和塞浦路斯型塊狀硫化物礦床。10西昆侖地區(qū)晚古生代發(fā)育在擴(kuò)張島弧環(huán)境的雙峰式火山巖、基性火山巖與上覆沉積巖相接觸的具有強(qiáng)烈蝕變的地層,是西昆侖地尋找VMS礦床的的重點(diǎn)層位,在地表常常形成鐵帽和黃鉀鐵礬帶。
[Abstract]:From south to north, the West Kunlun orogenic belt is divided into Karakoram earth, sweet water Haiti body, southern Kunlun earth body and Northern Kunlun earth body. A series of Late Paleozoic volcanic rocks are exposed in a large area of the northern Kunlun terrain and Tarim block, which is spread to the Khan Khan - Khan frontline of the north slope of the kungshan mountain and extends from West Kunlun Mountains to the West. The eastern part of Kunlun Mountains is a few thousand kilometers long. This late Paleozoic volcanic rock belt developed a series of small and medium sized VMS deposits, the cuprash copper gold deposit and the San Luo Yi copper deposit as the most representative deposit. This paper is based on the study of the cuprash copper gold deposit and the salt copper deposit as the basis of the systematic summary of the geological characteristics of the deposit. On the basis of the study of ore bearing volcanic rocks, the metallogenic tectonic environment, the age of diagenesis and mineralization, the source of metallogenic material, the analysis of the genetic types of the ore deposits and the establishment of the metallogenic model have been made. 1 through systematic analysis of the zircon U-Pb age of the actash volcanic rocks, Salo Bea Lvome and gigzananite, the systematic analysis of the age of zircon has been obtained. The northern slope of the Kun GI mountain, Kunlun, was originally divided into Carboniferous volcanic rocks. The age of the formation age should be the early two fold and Late Permian. The age of the actash volcanic rocks is 284.6Ma, the age of the zorai basalt is 263.0Ma, and the age of the igzanite is 263.8Ma.2 actash volcanic rocks at the beginning of the island arc expansion. The Shuangfeng type volcanic rocks and calc alkaline basalts with the nature of island arc pulls. The gezananite and soli basalt are relatively late N-MORB island arc basalts and island arc andesite. The age of the two diagenesis is nearly the same. Thus, it is presumed that the gzananite may be the same volcanic rock with the saluyi basalt. The rock geochemical characteristics of the Saloy basalt - gzananite reflect that the tectonic environment produced by the volcanic rocks is in the transitional stage between the island arc to the inter arc (post arc) basin and the rock geochemical characteristics of the alktash ore bearing surrounding rock through the study of the rock geochemistry of the alktash ore bearing rocks in the ore bearing rock. It is believed that the ore bearing surrounding rock of the actash deposit can be used in.3. The ore hosting rocks of the massive sulfide deposits produced in the Okinawa island arc of the Western Pacific Ocean are compared. The ore bearing surrounding rock of the saoli copper deposit is a occipital basalt, which is similar to the surrounding rock of the Cyprus type deposit by.4 to the detailed geochemical (ore earth) of the alktower copper gold deposit and the saoli copper deposit. The study of chemistry, surrounding rock geochemistry, S isotopes), all evidences show that the metallogenic material of Aktas copper gold deposit is mainly derived from volcanic rocks. The metallogenic material of the deposit is derived from the volcanic and marine sediments.5 through the analysis of the main trace elements of sulfide in the Aktas and the sulphoxide copper deposits, from the footwall to the footwall. The upper plate has obvious zoning laws. According to this, the mineralization process of the Aktas deposit and the zexo copper deposit is divided into three stages respectively. The mineralization process of the Aktas copper gold deposit is the "stage" of the volcano jet, the "stage" of the volcanic hydrothermal deposition, the "stage" of the ore bearing hot brine + volcanic hydrothermal deposition, and the zore deposit copper deposit. The metallogenic process is the "stage" of rich ore hot brine deposit, hot brine deposit + volcanic hydrothermal sedimentation "stage". The sulfur of the.6 Anke deposit in the "stage" of the ore bearing hot brine deposit is mainly derived from the magmatic jet, the sulphur deposit is a polysulfide source, the sulfur may be the sea water sulfur, the volcanic jet sulfur and the sedimentary sulfur are mixed with the same precipitation. The formation age of the accumulated massive sulfide deposits coincides with the age of the formation of volcanic rocks. Therefore, the age of the actag copper gold deposit is early Permian, and the age of the Re-Os isotope age of the pyrite in the Late Permian.8 acash copper gold deposit is different from that of the surrounding rock age. The Re-Os system of pyrite may not meet the homology condition, but it is reserved for the Re-Os age of pyrite. It is possible that the east mining area of the OAC deposit is the remnants of the Codi oate ophiolite suite. The contact relationship between the eastern mining area and the strata of the eastern mining area needs to be further studied by the.9 and the typical Sophie deposit. The types of massive sulfide deposits are compared. All of the two are typical VMS deposits associated with volcanic activity. The genetic types of the deposits are the Shuangfeng type volcanic rocks of the late Paleozoic in the extended island arc environment, the basic volcanic rocks and the overlying subsidence in the.10 West Kunlun region of the sub type massive sulfide deposits and the Cyprus type massive sulfide deposits, respectively. The strongly altered strata formed by the contact of the lithofacies are the key layers of the VMS deposit in the West Kunlun, and the iron cap and jarosite belt are often formed on the surface.
【學(xué)位授予單位】：中國科學(xué)院研究生院(廣州地球化學(xué)研究所)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：P588.14;P612
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本文編號(hào)：2025779