本文關鍵詞： 矽卡巖型鐵礦 地質特征 礦床成因 西石門　出處：《長安大學》2015年碩士論文　論文類型：學位論文

【摘要】：西石門鐵礦位于太行山南段,是我國最大的矽卡巖型鐵礦礦集區(qū)之一,大大小小的礦床現(xiàn)已發(fā)現(xiàn)100多處。由于各種因素的影響,礦體的形態(tài)比較復雜,礦體的形成時代主要是燕山期,礦體主要賦存在中酸性侵入巖與碳酸鹽巖的接觸帶上,本區(qū)的礦石類型比較單一,主要是磁鐵礦。本文通過詳細的野外地質調查及室內實驗研究,包括巖漿巖石學、巖石地球化學特征、巖石微量稀土元素特征、巖體形成年代及成因的研究,建立了西石門鐵礦的成礦模式。1.本文通過鋯石LA-ICP-MS原位微區(qū)U-Pb定年技術,對武安巖體中角閃正長巖進行了定年,獲得135.6±1.5Ma的結晶年齡,說明武安雜巖體的形成時間為燕山期,雜巖體的巖石學和地球化學特征表明:(1)雜巖體的巖石類型主要為角閃閃長巖、閃長巖一二長閃長巖和角閃正長巖以及閃長玢巖,閃長巖中發(fā)育有環(huán)帶結構斜長石;(2)武安雜巖體的地球化學特征顯示在巖漿演化過程中主要存在橄欖石、單斜輝石、含鈦氧化物和磷灰石等礦物的結晶分異,而斜長石結晶分異作用不明顯。然而,這樣的結晶分異作用很難解釋武安雜巖體具有高Mg#、Cr和似EMI的同位素組成特征。所以,武安雜巖體巖漿在演化的過程中勢必有地幔物質的加入,其可能是在巖漿的上升過程中也可以巖漿源區(qū)。2.蝕變分帶在空間上的分布是有規(guī)律的,其特點有:(1)蝕變帶主要發(fā)育于巖體與碳酸巖圍巖的接觸帶附近,蝕變規(guī)模很大,特別是垂直方向上自頂板圍巖向巖體深部延伸達數百米;(2)各帶產物之間一般具有明顯的界線;(3)不同帶間礦物成分的變化具有突變性。3.西石門鐵礦床鐵礦石S同位素組成研究顯示,鐵礦石中硫化物硫值變化范圍小,說明硫組成較穩(wěn)定。地�；驇r漿的δ34S一般變化于0~2‰,硬石膏δ34S=24.0‰~29.1‰,而典型蒸發(fā)沉硫δ34S=20‰~24‰。由此可見,邯鄲-邢臺地區(qū)矽卡巖型鐵礦床中黃鐵礦δ34S值介于地幔硫與沉積硫之間,這說明成礦流體可能來源于巖漿,并在上升的過程中捕獲了膏巖地層,使成礦流體δ34S值變大。本區(qū)鉛同位素模式年齡明顯的差異性可能表明,成礦作用的多期次性和成礦巖漿的多類型性。4.通過總結前人研究資料和野外調研,分析了西石門地區(qū)矽卡巖型鐵礦的控礦因素和成礦規(guī)律,指出了找礦標志。
[Abstract]:Xishimen Iron Mine is located in the southern section of Taihang Mountain. It is one of the largest skarn type iron ore deposits in China. More than 100 ore deposits, large and small, have been found. Due to the influence of various factors, the shape of ore bodies is quite complex. The orebody was mainly formed in Yanshanian period, and the orebody mainly occurred in the contact zone between intermediate-acid intrusive rocks and carbonate rocks, and the ore types in this area were relatively simple. Through detailed field geological investigation and laboratory experiments, including magmatic petrology, petrogeochemical characteristics, rock trace rare earth element characteristics, age and origin of rock formation, The metallogenic model of Xishimen iron deposit has been established. The U-Pb dating technique of zircon LA-ICP-MS in situ microzone has been used to dating the hornblende syenite of the Wuan rock body, and the crystallization age of the amphibolite has been obtained at 135.6 鹵1.5 Ma, indicating that the formation time of the Wuan complex is Yanshanian period. The petrological and geochemical characteristics of the complex show that the main rock types of the complex are hornblende, diorite, diorite, hornblende and diorite porphyrite. Geochemical characteristics of Wuan complex show that olivine, clinopyroxene, titanium oxide, apatite and other minerals are mainly differentiated during magmatic evolution. The crystallization differentiation of plagioclase is not obvious. However, it is difficult to explain that the Wuan complex has the characteristics of high #mg Cr and EMI like isotopic composition. During the evolution of the Wuan complex magma, the mantle material is bound to be added, which may be the magmatic source region .2. the distribution of the alteration zone in space is regular. The alteration zone is mainly developed near the contact zone between rock mass and carbonatite surrounding rock, and the alteration scale is very large. In particular, vertical direction from the roof surrounding rock to the depth of the rock up to hundreds of meters) the products of the belt generally have a clear boundary between the different zones of mineral composition changes have a mutation .3. Xishimen iron ore iron ore S in the same position. Studies on the composition of elements show that. The sulfur values of sulfides in iron ores vary in a small range, indicating that the sulfur composition is relatively stable. The 未 34s of mantle or magma generally change from 0 to 2 鈥，

本文編號：1513816