本文選題：成礦流體　切入點(diǎn)：巖石地球化學(xué)　出處：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：寶山銅鉬多金屬礦床位于小興安嶺—張廣才嶺鐵-銅-鉬-金多金屬成礦帶北端,是近年發(fā)現(xiàn)的研究程度較低的矽卡巖型礦床。本文在野外地質(zhì)調(diào)查的基礎(chǔ)上,結(jié)合室內(nèi)研究(薄片、光薄片、地球化學(xué)及流體包裹體),確定礦床地質(zhì)特征、地球化學(xué)特征,厘定了礦床成因。寶山銅鉬多金屬礦床產(chǎn)于花崗閃長巖與下寒武統(tǒng)鉛山組大理巖的內(nèi)外接觸帶,顯示出典型的矽卡巖型礦床特征。礦區(qū)發(fā)育2期侵入巖,早期片麻狀花崗巖屬弱過鋁質(zhì)、高硅、高鉀鈣堿性系列的俯沖型I型花崗巖;后期花崗閃長巖、正長花崗巖屬準(zhǔn)鋁質(zhì)-弱過鋁質(zhì)、高硅、鉀玄巖-高鉀鈣堿性系列的同碰撞I型花崗巖,與成礦有密切的關(guān)系。片麻狀花崗巖為俯沖環(huán)境,為松嫩-張廣才嶺地塊和佳木斯地塊之間陸間洋向西俯沖于松嫩-張廣才嶺地塊之下形成的;花崗閃長巖及正長花崗巖為同碰撞環(huán)境,為早三疊世“佳蒙地塊”與華北板塊北緣東段碰撞的產(chǎn)物。矽卡巖型礦石為主要的礦石類型。礦石構(gòu)造有浸染狀構(gòu)造、星散狀構(gòu)造、細(xì)脈浸染狀構(gòu)造;礦石結(jié)構(gòu)主要有粒狀結(jié)構(gòu)、鱗片狀結(jié)構(gòu)、共結(jié)邊結(jié)構(gòu)和固溶體分離結(jié)構(gòu)(乳滴狀結(jié)構(gòu)、葉片狀結(jié)構(gòu))等。根據(jù)野外及室內(nèi)鏡下礦物共生組合關(guān)系,將礦床成礦過程劃分為3期4個(gè)階段即矽卡巖期(干矽卡巖階段Ⅰ、濕矽卡巖階段Ⅱ)、石英硫化物期(石英-硫化物階段Ⅲ、碳酸鹽階段Ⅳ)及表生期。寶山銅鉬多金屬礦床的成礦流體屬于中-高溫、中-高鹽度和中等密度體系,礦床形成于中深成環(huán)境。隨著成礦作用的進(jìn)行,成礦流體表現(xiàn)出一定的演化規(guī)律,成礦流體包裹體的均一溫度、成礦壓力、成礦深度呈降低趨勢,成礦流體的鹽度具有從高鹽度向低鹽度的演化趨勢,成礦流體的密度逐漸增高。流體包裹體巖相學(xué)觀察結(jié)合測溫,在石英中可以發(fā)現(xiàn)包裹體沸騰的證據(jù),證明礦床金屬硫化物的沉淀為流體不混溶(沸騰)作用導(dǎo)致的。寶山銅鉬多金屬礦床顯示出典型的矽卡巖型礦床的特征,表現(xiàn)在控礦因素、礦石類型、礦體特征、圍巖蝕變特征、礦物組構(gòu)、礦物共生組合關(guān)系等特征。
[Abstract]:Baoshan copper-molybdenum polymetallic deposit is located at the northern end of the Xiaoxing'anling Zhangguangcailing iron copper-molybdenum gold polymetallic metallogenic belt. It is a skarn type deposit which has been discovered in recent years.On the basis of field geological survey, combined with laboratory studies (thin sheet, light sheet, geochemistry and fluid inclusions), the geological and geochemical characteristics of the deposit are determined, and the genesis of the deposit is determined.Baoshan copper-molybdenum polymetallic deposit occurs in the inner and outer contact zone between granodiorite and lower Cambrian lead-shan marble, which shows the typical skarn type deposit.The intrusive rocks of the second stage are developed in the ore area. The early granitic granites are subducted type I granites of weak peraluminous, high silicon and high potassium calc-alkaline series, while the late granodiorite and syenite are quasi-alumina-weak peraluminous, high-silicon granitic granodiorite.The syncollisional I type granites of high K calc alkaline series are closely related to mineralization.The granodiorite is a subduction environment, formed by a westward subduction of the continental ocean between the Songnen-Zhangguangcailing and Jiamusi massif, and the granodiorite and syenite are in the same collision environment.It is the product of the collision between the early Triassic Jiameng Block and the eastern segment of the North China plate.Skarn type ore is the main ore type.The ore structure includes disseminated structure, scattered structure and vein-like structure, and the ore structure mainly consists of granular structure, scale-like structure, cojunction structure and solid solution separation structure (emulsion dripping structure, blade structure) and so on.According to the mineral symbiotic assemblages in the field and under indoor mirror, the metallogenic process of the deposit can be divided into three stages: skarn stage (dry skarn stage 鈪，

本文編號(hào)：1727455