本文選題：南泥湖 + 上房溝　； 參考：《中國地質(zhì)大學(北京)》2015年碩士論文

【摘要】：東秦嶺鉬多金屬成礦帶位于秦嶺造山帶東端,是世界最重要的鉬礦帶之一,南泥湖鉬鎢礦床和上房溝鉬鐵礦床是東秦嶺鉬礦帶兩個典型的超大型礦床,都屬于斑巖-矽卡巖型礦床。兩個礦床的成巖成礦年齡基本一致(燕山中期),且地理位置相近,然而兩個礦床的伴生礦種卻顯著不同,一個為鉬鎢礦床,一個為鉬鐵礦床。為此本文試圖通過對比兩個礦床的礦床地質(zhì)特征、圍巖性質(zhì)、巖石地球化學特征以及礦床地球化學特征,總結(jié)分析其成巖成礦的共性特征和差異特征,分析差異來源,為日后東秦嶺勘探提供參考。對比研究取得以下幾點認識成果:兩個礦床主要成礦期都為燕山中期。燕山期巖漿活動為該區(qū)多鉬鎢多金屬成礦提供了熱液和礦物質(zhì)來源,礦床在成因上與構(gòu)造、巖體、圍巖及其蝕變密切相關(guān)。南泥湖巖體和上房溝巖體均具有高硅、富堿的特征,均具有明顯的Eu負異常,分異演化強烈。稀土和稀有元素顯示兩個巖體具有后造山花崗巖、同碰撞和后碰撞花崗巖過渡特征。稀有元素、鍶、釹同位素指示巖體來源為殼�；煸�。黑云母成分特征顯示巖體形成時氧逸度和溫度較高,形成的深度為中淺成。兩個礦床的硫、碳氧、氫氧和鉛同位素及錸含量特征表明兩個礦床的鉬鎢成礦物質(zhì)都是巖體由深部帶來,成礦流體與斑巖關(guān)系密切,后期可能有地層物質(zhì)和大氣降水的加入。流體包裹體都富集CO2,都經(jīng)歷從高溫到低溫的演化。兩個礦床的差異性主要體現(xiàn)在:1)南泥湖主要伴生礦種為W,而上房溝主要伴生Fe;2)南泥湖礦床的成礦母巖是黑云母二長花崗巖,上房溝則為堿長花崗斑巖;3)南泥湖圍巖相對富鎂,主要發(fā)育鈣矽卡巖化、鉀交代等蝕變,上房溝圍巖相對富鈣,主要發(fā)育鎂矽卡巖化、鉀交代和硅交代等蝕變作用。決定兩個礦床伴生礦種差異的是圍巖性質(zhì)。上房溝的鐵礦為接觸交代型(矽卡巖型),通過鈉交代作用和成巖成礦溫度氧逸度的橫向?qū)Ρ?判斷巖漿源并非上房溝單一的鐵質(zhì)來源,根據(jù)蝕變過程中主要組分變化曲線圖,推測鐵質(zhì)來源可能為變輝長巖。
[Abstract]:The east Qinling molybdenum polymetallic metallogenic belt is located at the eastern end of the Qinling orogenic belt and is one of the most important molybdenum ore belts in the world. The South Nihu molybdenum tungsten deposit and Shangfanggou molybdenum iron deposit are two typical superlarge deposits in the east Qinling molybdenum ore belt. All belong to porphyry-skarn type deposit. The diagenetic and metallogenic ages of the two deposits are basically the same (the middle Yanshanian period) and the geographical location is similar. However, the associated ore types of the two deposits are obviously different, one is molybdenum tungsten deposit and the other is molybdenum iron deposit. For this reason, this paper attempts to summarize and analyze the common and differential characteristics of diagenesis and metallogenesis by comparing the geological characteristics, surrounding rock properties, rock geochemistry characteristics and deposit geochemical characteristics of the two deposits, and analyzes the source of the differences. It provides a reference for the exploration of the East Qinling Mountains in the future. The results are as follows: the main metallogenic period of the two deposits is the middle Yanshanian period. Yanshanian magmatic activity provided hydrothermal and mineral source for polymolybdenum and tungsten polymetallic mineralization in this area. The ore deposit is closely related to structure, rock mass, surrounding rock and its alteration in origin. Both the Nannihu and Shangfanggou rock bodies are characterized by high silicon and alkali, obvious negative EU anomalies and strong differentiation and evolution. The REE and REE show that the two intrusions have the characteristics of post-orogenic granite, syncollision and post-collisional granite transition. Rare elements, strontium and neodymium isotopes indicate that the source of the rock mass is crust and mantle mixing. The composition characteristics of biotite show that the oxygen fugacity and temperature are high and the depth of formation is medium and shallow. The characteristics of sulfur, carbon, oxygen, hydrogen, oxygen and lead isotopes and rhenium contents in the two deposits indicate that the molybdenum and tungsten ore-forming minerals in the two deposits are all brought by the deep rock mass, and the ore-forming fluid is closely related to porphyry, and there may be stratigraphic material and atmospheric precipitation in the late stage. Fluid inclusions are rich in CO _ 2 and have evolved from high temperature to low temperature. The difference between the two deposits is mainly reflected in: (1) the main associated minerals in Nanni Lake are W, while in Shangfanggou are associated with Feji2) the ore-forming mother rock of Nannihu deposit is biotite monzogranite, and Shangfanggou is alkali-feldspar porphyry 3) the surrounding rock of Nanjihu Lake is relatively rich in magnesium. There are mainly calcium-skarn alteration, potassium metasomatism and other alteration. The surrounding rock of Shangfanggou is relatively rich in calcium, and mainly developed magnesia-skarn, potassium metasomatism and silicon metasomatism. It is the nature of surrounding rock that determines the difference of the associated minerals between the two deposits. The iron ore in Shangfanggou is of contact metasomatic type (skarn type). Through the lateral comparison of sodium metasomatism and the oxygen fugacity of the ore-forming temperature, it is determined that the magmatic source is not a single iron source in Shangfanggou. It is speculated that the source of iron may be metamorphic gabbro.
【學位授予單位】：中國地質(zhì)大學(北京)
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P618.2

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