本文選題：剛玉　切入點(diǎn)：寄主巖石　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：剛玉產(chǎn)于富Al貧Si的地球化學(xué)背景下,代表了高溫礦物的形成環(huán)境,在地質(zhì)學(xué)領(lǐng)域很有研究?jī)r(jià)值。達(dá)到寶石級(jí)的剛玉可作為紅藍(lán)寶石產(chǎn)出,和祖母綠、鉆石和貓眼一起并稱五大名貴寶石,作為一種很名貴的寶石其經(jīng)濟(jì)價(jià)值也是不言而喻的。由于全球產(chǎn)寶石級(jí)剛玉的礦床并不多,河北阜平剛玉的資料也相對(duì)匱乏,前人研究程度不是很深,對(duì)于阜平剛玉成因的認(rèn)識(shí)目前也比較混亂,這一系列的問(wèn)題都亟待解決,因此,對(duì)阜平剛玉的產(chǎn)出特征和成因機(jī)制開(kāi)展研究工作是很有必要的,這也可以為今后的剛玉寶石找礦工作提供一定方向。野外觀察阜平地區(qū)剛玉寄主巖石的巖性主要為花崗質(zhì)混合巖和夕線石混合巖。剛玉寄主巖石主要由暗色的基體和淺色的脈體組成,暗色基體部分的巖石為粒狀變晶結(jié)構(gòu)、片麻狀構(gòu)造(放射狀構(gòu)造),在淺色脈體部分,剛玉和長(zhǎng)石呈中粗�；◢徑Y(jié)構(gòu)、塊狀構(gòu)造。剛玉寄主巖石一個(gè)顯著特點(diǎn)是,長(zhǎng)石含量非常高,幾乎環(huán)繞了整個(gè)剛玉晶體,呈眼球狀構(gòu)造。根據(jù)巖相學(xué)特征以及巖石地球化學(xué)特征得知,阜平地區(qū)剛玉礦床屬于深熔型混合巖化作用成因,即“混合巖型”。剛玉礦床的形成主要經(jīng)歷了區(qū)域變質(zhì)作用、混合巖化作用以及退化變質(zhì)作用三個(gè)階段,而剛玉的形成主要在前兩個(gè)階段。區(qū)域變質(zhì)作用階段形成的剛玉(世代I)粒度太小,達(dá)不到寶石級(jí)剛玉粒度。混合巖化作用階段形成含剛玉晶體(世代II)的淺色脈體,此階段形成的剛玉的晶體較粗大,達(dá)到寶石級(jí)粒度的標(biāo)準(zhǔn)。對(duì)該區(qū)剛玉形成機(jī)理進(jìn)行了探討,認(rèn)為其是在片麻巖發(fā)生混合巖化過(guò)程中,形成富鋁質(zhì)的熔漿結(jié)晶而成。但在不同的區(qū)域,所形成有成份差異的富鋁熔漿是導(dǎo)致礦物組合產(chǎn)生差異的主要原因。桃花村、王家莊村剛玉礦床形成的溫度范圍為600℃~730℃,壓力范圍為0.3~1.0GPa。邁嶺地區(qū)剛玉礦床形成溫度范圍為484℃~700℃,壓力范圍為0.1~0.8GPa。均為高角閃巖相-麻粒巖相。通過(guò)寶石學(xué)特征研究以及質(zhì)量評(píng)價(jià)來(lái)看,阜平地區(qū)的剛玉具備作為寶石開(kāi)發(fā)利用的潛力,然而投入市場(chǎng)價(jià)格如何需要進(jìn)一步的研究與探討。
[Abstract]:Corundum, which is rich in Al and poor in Si, represents the forming environment of high temperature minerals and is of great value in the field of geology. Corundum of gemstone grade can be used as ruby sapphire and emerald. Diamonds and cat eyes are known as the five most valuable gemstones together. As a very valuable gem, its economic value is also self-evident. Because there are not many deposits of gemstone grade corundum in the world, the data on corundum in Fuping, Hebei Province, is also relatively scarce. The previous studies are not very deep, and the understanding of the origin of Fuping corundum is also confused at present. All these problems need to be solved urgently. Therefore, it is necessary to carry out research work on the production characteristics and genetic mechanism of Fuping corundum. In the field, the lithology of corundum host rocks in Fuping area is mainly composed of granitic migmatite and skirlite migmatite. Corundum host rocks are mainly composed of dark base. Body and light-colored veins, The rocks in the dark matrix are grained and grained, and the lamellar structure (radial structure), in the light vein part, corundum and feldspar are of medium coarse granitic structure and block structure. A prominent feature of corundum host rocks is that, The content of feldspar is very high, it almost encircles the whole corundum crystal and takes on eyeball structure. According to the petrographic and petrogeochemical characteristics, the corundum deposit in Fuping area belongs to the origin of deep-melt mixed lithology. The formation of corundum deposits mainly experienced three stages: regional metamorphism, migmatization and degenerative metamorphism. The formation of corundum is mainly in the first two stages. The grain size of corundum (generation I) formed in the regional metamorphism stage is too small to reach the grain size of gemstone grade corundum. The formation mechanism of corundum in this area is discussed. It is considered that the formation mechanism of corundum is in the process of gneiss migmatization. But in different regions, the main reason for the difference of mineral assemblage is that the aluminum-rich melts formed in different regions. The temperature range of formation of corundum deposits in Taohua Village and Wangjiazhuang Village is 600 鈩，

本文編號(hào)：1607988