本文關(guān)鍵詞： 德爾尼銅礦 海底噴流沉積 礦床成因 找礦方向　出處：《中國地質(zhì)大學(xué)(北京)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：德爾尼銅礦位于青海省布青山—積石山銅多金屬成礦帶上,屬阿尼瑪卿晚古生代造山帶東段,由于該成礦帶經(jīng)歷了前寒武紀(jì)不同地塊構(gòu)造基底的復(fù)雜演化以及強烈構(gòu)造運動,形成了廣泛分布礦區(qū)的蛇綠混雜巖帶,再加上后期造山運動的疊加與各種沉積建造等的組合,最終形成了多金屬礦化帶。自該礦床發(fā)現(xiàn)以來,關(guān)于其成因的爭論一直存在爭議,各種原因有各自的證據(jù),如深部熔離礦床、花崗巖熱液礦床以及海底熱液礦床等。因此,對于該礦床的成因研究具有較重要的意義,這也有助于為以后的找礦工作有一定的指導(dǎo)意義。所以,本文通過電子顯微鏡鏡下觀察和電子探針及礦物年齡等實驗研究,探討了礦床的成因,為礦床以后的開采工作提供了一定的指向。通過野外觀察及礦相學(xué)研究,大致將德爾尼銅礦床中主要礦石礦物成礦期次進行了總結(jié),認為最主要礦石礦物黃鐵礦分為三期,黃銅礦、閃鋅礦分為兩期,磁黃鐵礦、磁鐵礦共有一期。根據(jù)電子探針數(shù)據(jù),得出礦體中黃鐵礦、黃銅礦、閃鋅礦等主要礦物產(chǎn)生于中低溫?zé)嵋涵h(huán)境下。巖石地球化學(xué)特征分析得出,斜長角閃巖為一套基性-超基性巖為主的組合,其主要巖石類型有安山巖、玄武巖、苦橄巖等,具低鉀偏鋁質(zhì)鈣堿性特征。稀土元素方面呈輕稀土富集,重稀土虧損的特征,具有微弱的銪正異常;巖石中大離子親石元素Rb、Ba、Sr等元素明顯富集,高場強元素Nb、Ta、U相對虧損,而Pb、Zr等元素與原始地幔相當(dāng)或略有富集。研究區(qū)鋯石U-Pb年代學(xué)研究表明,其成礦時間為310.0±4.7Ma,屬于晚石炭世。經(jīng)過研究,初步認為德爾尼銅多金屬礦床是以海底噴流—沉積成礦為主體,以后期疊加成礦為特色的復(fù)合成礦作用的礦床,歸納為成礦熱液沿裂隙噴出和沉積,礦體頂部存在一套含碳鐵硅質(zhì)板巖,超基性巖在后期構(gòu)造作用影響下對主礦體擠壓變形,在接觸部位影響了鈷礦及磁黃鐵礦等疊加成礦的過程,礦床在隨后的疊加成礦過程中經(jīng)歷了多種形式的構(gòu)造破壞和位置的變動,并且在此基礎(chǔ)上提出了德爾尼礦床的找礦標(biāo)志,即:褶皺構(gòu)造轉(zhuǎn)折端、構(gòu)造角礫巖帶、超基性巖體片理化帶、超基性巖體與圍巖接觸帶、逆沖推覆構(gòu)造下盤、超基性巖構(gòu)造透鏡體。
[Abstract]:Delney copper deposit is located in the Buqingshan-Jishi mountain copper polymetallic metallogenic belt in Qinghai Province, which belongs to the eastern section of the late Paleozoic orogenic belt. Due to the complex evolution of the tectonic basement of different Precambrian blocks and the strong tectonic movement, the metallogenic belt formed a widely distributed ophiolite melange belt. Combined with the combination of late orogeny and various sedimentary formations, the polymetallic mineralization zone was formed. Since the discovery of the deposit, there has been controversy about its genesis. All kinds of reasons have their own evidences, such as deep melt deposit, granite hydrothermal deposit and submarine hydrothermal deposit, etc. Therefore, it is of great significance to study the genesis of the deposit. Therefore, through the observation of electron microscope and the experimental study of electron probe and mineral age, the origin of ore deposit is discussed in this paper. Through field observation and mineralogical study, the metallogenic stages of main ore minerals in Delney copper deposit are summarized. It is considered that the main ore mineral pyrite is divided into three stages, chalcopyrite and sphalerite are divided into two periods, and pyrrhotite and magnetite have one phase altogether. According to the data of electron probe, the pyrite and chalcopyrite in the orebody are obtained. The main minerals such as sphalerite are produced in the medium and low temperature hydrothermal environment. The petrogeochemical characteristics show that the amphibolite is a combination of basic-ultrabasic rocks, and its main rock types are andesite and basalt. Picrite is characterized by low potassium metamorphic calc-alkaline. Rare earth elements are enriched in light rare earth elements and depleted in heavy rare earth elements with weak europium positive anomalies. The large ion lithophile elements, such as RB, Bao, Sr and so on, are obviously enriched in the rocks, and the high field strength element Nbtadao U is relatively depleted, while Pb is found. The zircon U-Pb chronology in the study area shows that the metallogenic time of zircon is 310.0 鹵4.7 Ma, which belongs to the late Carboniferous. It is preliminarily considered that the Delnier copper polymetallic deposit is a kind of composite metallogenic deposit characterized by submarine exhalation and depositional metallogeny and characterized by late superposition metallogeny. It can be concluded that the ore-forming hydrothermal fluid ejects and deposits along the fissure. There is a set of carbonaceous iron-siliceous slate at the top of the orebody. The ultrabasic rock compresses and deforms the main orebody under the influence of late tectonics, and affects the superposition process of cobalt ore and pyrrhotite in the contact position. The ore deposit experienced various forms of structural failure and change of location during the subsequent superposition and metallogenic process. On the basis of this, the ore-prospecting markers of Delney deposit were put forward, that is, fold tectonic turning end and tectonic breccia belt. The physical and chemical zones of ultrabasic rock body, the contact zone between ultrabasic rock body and surrounding rock, the overthrust tectonic footwall, and the ultrabasic rock structural lens.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：P618.2

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