本文關(guān)鍵詞： 查干德爾斯 鉬礦 花崗巖 巖石地球化學(xué) 鋯石U-Pb測年　出處：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：查干德爾斯鉬礦床地處內(nèi)蒙古烏拉特后旗北東方向,是近年來在中蒙邊境地區(qū)發(fā)現(xiàn)的一個具有大型規(guī)模的隱伏礦床。該鉬礦大地構(gòu)造位置位于華北古陸西北緣,蘇吉音花復(fù)式背斜南翼,寶音圖隆起中段,其成礦與區(qū)內(nèi)由斜長花崗巖-二長花崗巖-鉀長花崗巖-細晶花崗巖組成的復(fù)合巖體密切相關(guān),一般認為該礦床具斑巖型礦床的特點。本文主要對該復(fù)合巖體的地球化學(xué)及年代學(xué)特征進行研究。鋯石U-Pb同位素測年顯示,該復(fù)合巖體年齡225.9±4.4Ma~256.6±3.4Ma,屬于印支期復(fù)合巖體。從斜長花崗巖、二長花崗巖、鉀長花崗巖到細晶花崗巖的年齡逐漸變小,斜長花崗巖為252.1±3.4 Ma~256.6±3.4Ma;二長花崗巖247.5±4.4 Ma;鉀長花崗巖236.8±4.5 Ma~244.3±4.2Ma;細晶花崗巖為225.9±4.4Ma。因此,可以看出,不同巖性分別代表了巖漿的不同演化階段。輝鉬礦錸鋨等時限年齡為239.2±5.8Ma。該成礦年齡與復(fù)合巖體年齡225.9±4.4Ma~256.6±3.4Ma接近,因此屬于印支期花崗巖侵入成礦,成礦年齡介于鉀長花崗巖成巖階段(236.8±4.5 Ma~244.3±4.2 Ma)。但對比鄰區(qū)查干花鉬礦,查干德爾斯礦區(qū)成巖成礦時間差上可能也具有相似特點,并且考慮到在細晶花崗巖(225.9±4.4Ma)中可見礦化石英細脈,其成礦也可能持續(xù)到細晶花崗巖巖脈形成之后。因此,總體來看,查干德爾斯礦區(qū)不同階段侵入的不同巖性的花崗巖可能均與成礦有關(guān)。巖石地球化學(xué)特征顯示,復(fù)合花崗體四種巖性均具有高硅、過鋁、富堿,高鉀鈣堿性的主量元素特點;微量元素及稀土元素特征也表明該復(fù)合花崗巖體屬于陸殼熔融成因花崗巖。在另一方面,復(fù)合花崗巖體巖體成分逐漸變化,巖漿演化過程中成分有所分異,但各類巖漿巖差異并不明顯,分異較為微弱,這是由于每個巖漿侵入階段間隔時間較短,巖漿來不及充分集中分異,而這種作用也許有利于化學(xué)性質(zhì)活躍的成礦元素快速集中于晚期巖漿巖中�；◢弾r成巖背景研究顯示,復(fù)合巖體可能是由元古代寶音圖群變質(zhì)巖,在晚二疊世后,于后碰撞環(huán)境中部分熔融而成。
[Abstract]:The Chagandels molybdenum deposit is located in the north-eastern direction of Houqi, Wurat, Inner Mongolia, and is a large scale concealed deposit discovered in the border area between China and Mongolia in recent years. The tectonic location of the deposit is located in the northwestern margin of the North China Paleocontinent. The southern wing of Sujiyinhua complex anticline and the middle segment of Bao Yin's uplift are closely related to the complex rock body composed of plagioclase granite, bifeldspar granite, potassium feldspar granite and fine-grained granite. It is generally considered that the deposit has the characteristics of porphyry type deposit. The geochemistry and geochronology of the complex are studied in this paper. The zircon U-Pb isotopic dating shows that, The age of the complex is 225.9 鹵4.4 Ma-256.6 鹵3.4 Ma, which belongs to the Indosinian complex. The age from plagioclase granite, monzomorphic granite, potassium feldspar granite to fine-grained granite has gradually decreased. It was 252.1 鹵3.4 Ma, 256.6 鹵3.4 Ma, 247.5 鹵4.4 Ma, 236.8 鹵4.5 Ma~244.3 鹵4.2 Ma, 225.9 鹵4.4 Ma. for plagioclase granite, 247.5 鹵4.4 Ma, 225.9 鹵4.4 Ma for fine-grained granite, respectively. Different lithology represents different stages of magma evolution. The isochron age of molybdenum ore rhenium and osmium is 239.2 鹵5.8 Ma.The ore-forming age is close to that of complex rock mass (225.9 鹵4.4 Ma-256.6 鹵3.4 Ma), so it belongs to Indosinian granitic intrusive mineralization. The ore-forming age is between 236.8 鹵4.5 Ma~244.3 鹵4.2Ma.However, for Chagan molybdenum deposit in the adjacent area, the time difference of diagenesis and mineralization in Chagandels ore area may also have similar characteristics, and considering that mineralized quartz veins can be seen in fine-grained granite (225.9 鹵4.4 Maa), The mineralization may also continue after the formation of the fine-grained granite veins. Therefore, in general, the different lithologic granites intruded at different stages of the Chagandels ore area may be related to mineralization. The four kinds of lithology of the composite granitic body all have the main element characteristics of high silicon, peraluminum-rich alkali, high potassium calc-alkaline, trace elements and rare earth elements, which also indicate that the composite granitic body belongs to the continental crust melting origin granite, on the other hand, The composition of composite granite body changes gradually, and the composition of magmatic evolution is different, but the difference of magmatic rock is not obvious, but the differentiation is weak, which is due to the short time interval between each magmatic intrusive stage. There is no time for magma to concentrate and differentiate fully, and this process may be conducive to the rapid concentration of chemically active ore-forming elements in late magmatic rocks. Studies on the diagenetic background of granitic rocks indicate that the composite rocks may be metamorphic rocks from the Proterozoic Bao Yin group. After the late Permian, it was partially melted in the post-collision environment.
【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】：2015
【分類號】：P618.65
，

本文編號：1497113