本文選題：鋯石U-Pb + LA-ICP-MS��； 參考：《新疆大學(xué)》2016年碩士論文

【摘要】：研究區(qū)位于額爾齊斯大斷裂北側(cè),西北為國(guó)界。研究區(qū)內(nèi)巖漿活動(dòng)較強(qiáng),巖石類型復(fù)雜,前人對(duì)其作過(guò)較多的地質(zhì)工作,但對(duì)阿爾泰造山帶西段侵入巖研究較少。本文通過(guò)同位素年代學(xué)、巖石學(xué)、地球化學(xué)及野外地質(zhì)觀察等手段,對(duì)新疆阿爾泰造山帶西段沖乎爾地區(qū)侵入巖的巖漿序列進(jìn)行了研究,對(duì)研究區(qū)侵入巖巖漿序列、巖石成因及構(gòu)造環(huán)境研究提供重要依據(jù)。取得了以下認(rèn)識(shí):本文對(duì)研究區(qū)內(nèi)1:5萬(wàn)區(qū)調(diào)成果的基礎(chǔ)上,選擇了4個(gè)巖體,并根據(jù)路線信息、剖面信息及鋯石U-Pb年代學(xué)數(shù)據(jù),最后確定了其侵入序列、巖石成因類型及構(gòu)造環(huán)境。通過(guò)U-Pb測(cè)年數(shù)據(jù)分析,研究區(qū)內(nèi)侵入巖巖漿序列劃分為奧陶紀(jì)侵入序列和晚志留-早泥盆紀(jì)侵入序列等兩個(gè)序列;其LA-ICP-MS年齡為:喀拉斯片麻狀黑云母二長(zhǎng)花崗巖473.3±2.9Ma,比列烏提溪黑云母花崗巖469.8±2.9Ma,阿尤特山東南破片麻狀黑云母二長(zhǎng)花崗巖455.3±3.1Ma。鐵列里克片麻狀英云閃長(zhǎng)巖420.6±3.0Ma及414.8±2.6Ma。奧陶紀(jì)序列侵入巖體具有一致的地球化學(xué)特征,高硅、高堿、高鉀,過(guò)鋁飽和型,屬于鈣堿性系列;具有輕稀土富集,重稀土分餾明顯,其成因應(yīng)該是部分陸殼熔融物質(zhì)。晚志留-早泥盆紀(jì)序列侵入巖體具有輕稀土富集,重稀土虧損,輕重稀土分餾明顯等特征,其成因是部分陸殼熔融。經(jīng)巖石化學(xué)特征、微量、稀土元素地球化學(xué)特征研究以及巖體成因類型圖解判別,得知奧陶紀(jì)侵入序列巖體均為S型花崗巖,晚志留-早泥盆紀(jì)侵入序列巖體為I-S型花崗巖;研究區(qū)震旦紀(jì)構(gòu)造運(yùn)動(dòng)(拉張)使蒙古-阿爾泰洋褶皺、回返,最后關(guān)閉奧陶紀(jì)古亞洲洋向西伯利亞板塊俯沖形成喀納斯一帶東錫勒克組中酸性火山巖;泥盆紀(jì)是板塊俯沖-碰撞造山的主要時(shí)期,最后使阿爾泰陸緣活動(dòng)帶固結(jié)成新陸殼,進(jìn)入陸內(nèi)發(fā)展階段。
[Abstract]:The study area is located on the north side of Erzis fault, northwest for the national boundaries.The magmatic activity in the study area is stronger and the rock types are complex. More geological work has been done on it, but less on the intrusive rocks in the western part of the Altai orogenic belt.By means of isotopic geochronology, petrology, geochemistry and field geological observation, the magmatic sequence of intrusive rocks in Chonghur area, western section of Altai orogenic belt, Xinjiang, has been studied in this paper.The study of petrogenesis and tectonic environment provides important basis.The following conclusions have been obtained: based on the results of the 1: 50 000 regional survey in the study area, four rock masses were selected, and the intrusive sequence was determined according to the route information, profile information and zircon U-Pb chronology data.Petrogenetic types and tectonic setting.The magma sequences of intrusive rocks in the study area are divided into Ordovician intrusion sequence and late Silurian early Devonian intrusion sequence by U-Pb dating analysis.Its LA-ICP-MS age is 473.3 鹵2.9Mafor granitic granites, 469.8 鹵2.9Mafor biotite granites and 455.3 鹵3.1Ma.The granitic diorite is 420.6 鹵3.0Ma and 414.8 鹵2.6 Ma.The Ordovician series intrusive rock body has the same geochemical characteristics, high silicon, high alkali, high potassium, supersaluminous saturation type, belong to calc-alkaline series, it has light rare earth enrichment, heavy rare earth fractionation is obvious, its origin should be part of continental crust melt material.The late Silurian and early Devonian intrusive rocks are characterized by the enrichment of LREE, the depletion of heavy REE and the obvious fractionation of LREE, which is caused by partial continental crust melting.Based on the petrochemical characteristics, trace and rare earth element geochemical characteristics and diagrammatic discrimination of the genetic types of the intrusive rocks, it is concluded that the Ordovician intrusive sequence is S-type granite, and the late Silurian early Devonian intrusive sequence is I-S type granite.The Sinian tectonic movement (extension) made the Mongolian-Altai ocean fold return and finally closed the Ordovician Paleo-Asian Ocean subducting toward the Siberian plate to form intermediate-acid volcanic rocks of the East Sirake formation in Kanas area.Devonian was the main period of plate subduction-collision orogeny and finally consolidated the active belt of Altai continental margin into a new continental crust and entered the stage of intracontinental development.
【學(xué)位授予單位】：新疆大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：P542;P588.12

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 徐義剛,梅厚鈞,許繼峰,黃小龍,王岳軍,鐘孫霖;峨眉山大火成巖省中兩類巖漿分異趨勢(shì)及其成因[J];科學(xué)通報(bào);2003年04期

2 王玉往;王京彬;王莉娟;方同輝;;新疆尾亞礦區(qū)3期巖漿混合作用的初步研究[J];中國(guó)地質(zhì);2007年02期

3 齊有強(qiáng);胡瑞忠;劉q，

本文編號(hào)：1739552