本文關(guān)鍵詞：青海同德加吾礦區(qū)巖漿作用及鎢礦成礦機理研究　出處：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文　論文類型：學(xué)位論文

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【摘要】：青海同德加吾礦區(qū)處于青海南山微造山帶,屬于西秦嶺造山帶與東昆侖造山帶的接觸部位。本文通過巖相學(xué)、全巖地球化學(xué)、礦物學(xué)、流體地球化學(xué)的研究,結(jié)合前人資料,進一步闡述加吾礦區(qū)巖漿巖的成因與金屬礦物成因,探討了區(qū)域動力學(xué)、熱力學(xué)特征及白鎢礦成礦機理,對于指導(dǎo)該區(qū)地質(zhì)找礦具有重要的意義。通過本次研究,取得了以下主要成果與認識:加吾礦區(qū)花崗巖類均為I型花崗巖。花崗閃長巖具有富鈉、貧鉀、過鋁質(zhì)、高鉀鈣堿性花崗巖特征;富集大離子親石元素(LILE):銣、鋇、鈾、釷,輕度虧損高場強元素(HFSE):鈮、鉭、鈦;輕重稀土分餾明顯,銪、鈰異常不明顯,鍶輕微負異常�；◢彴邘r具有富鈉、貧鉀、過鋁質(zhì)、鈣堿性花崗巖特征;富集大離子親石元素(LILE):銣、鋇,虧損高場強元素(HFSE):鈮、鉭、鈦;輕重稀土的分異較大,釔值含量較低,同時具有弱銪負異常,鍶含量低。結(jié)合區(qū)域動力學(xué)研究及成巖時代分析,花崗斑巖源自老地殼,花崗閃長巖源自巖石圈地幔。加吾礦區(qū)不同產(chǎn)出狀態(tài)含礦石英脈流體包裹體類型主要為富液包裹體,成礦流體溫度總體在200~290°C,鹽度總體小于10wt%Na Cl,顯示出淺成低溫?zé)嵋禾卣�。成礦流體的氫氧同位素特征指示其很可能來源于巖漿流體,同時不排除混入少量變質(zhì)流體的可能性。電子探針分析顯示白鎢礦主要成分與理論值相比,鎢含量偏低,而鈣含量略偏高,鉬含量低于0.1%。通過與不同類型白鎢礦成分組成進行對比,加吾白鎢礦顯示出石英脈型白鎢礦的特點;同時,WO3-Ca O關(guān)系和白鎢礦陽離子W-Mo-Ca三角圖解分析,加吾白鎢礦均顯示為石英脈型白鎢礦。綜上所述,加吾鎢礦床成礦流體表現(xiàn)出淺成低溫?zé)嵋禾卣?其成因上與該區(qū)花崗巖類關(guān)系密切,礦床類型為石英脈型白鎢礦。
[Abstract]:Tongde Jiawu ore area in Qinghai is located in the Nanshan microorogenic belt, which belongs to the contact site between the West Qinling orogenic belt and the East Kunlun orogenic belt. This paper studies the petrography, whole rock geochemistry, mineralogy and fluid geochemistry. Based on the previous data, the genesis of magmatic rocks and metal minerals in Jiawu mining area is further expounded, and the regional dynamics, thermodynamic characteristics and metallogenic mechanism of scheelite are discussed. It is of great significance to guide geological prospecting in this area. Through this study, the following main achievements and understandings have been obtained: the granitoids in Jiawu mining area are all I-type granites, and granodiorite is rich in sodium and poor in potassium. Peraluminous, high-potassium calc-alkaline granites; Enrichment of large ion lithophile elements Lilei: rubidium, barium, uranium, thorium, slightly depleted high field strength elements HFSE: niobium, tantalum, titanium; The fractionation of heavy and heavy rare earths is obvious, the anomaly of europium and cerium is not obvious, and the anomaly of strontium is slightly negative. The granitic porphyry is characterized by rich in sodium, poor in potassium, peraluminous and calc-alkaline granite. Enrichment of large ion lithophile elements Lilei: rubidium, barium, depleted high field strength elements HFSE: niobium, tantalum, titanium; The heavy and heavy rare earth elements have large differentiation, low yttrium content, weak europium negative anomaly and low strontium content. Combined with regional dynamics and diagenetic age analysis, granitic porphyry originated from the old crust. The granodiorite originates from the lithospheric mantle. The fluid inclusions of different ore-bearing veins in Jiawu ore area are mainly liquid-rich inclusions, and the temperature of ore-forming fluid is generally at 290 擄C. The salinity is less than 10 wtNa Cl, showing the characteristics of epithermal hydrothermal solution. The hydrogen and oxygen isotopic characteristics of the ore-forming fluid indicate that it probably originated from the magmatic fluid. At the same time, the possibility of mixing a small amount of metamorphic fluid is not excluded. Electron probe analysis shows that the main composition of scheelite is lower than the theoretical value, and the content of calcium is slightly higher. The molybdenum content is less than 0.1%. Compared with the composition of different types of scheelite, Jiawu scheelite shows the characteristics of quartz vein type scheelite. At the same time, the WO _ 3-CaO relationship and W-Mo-Ca triangular diagram analysis of scheelite show that the scheelite is quartz vein type scheelite. The ore-forming fluid of Jiawu tungsten deposit shows the characteristics of epithermal hydrothermal formation, and its genesis is closely related to the granitic type in this area, and the type of deposit is quartz vein type scheelite deposit.
【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】：2017
【分類號】：P618.67

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本文編號：1419736