【摘要】：研究區(qū)位于青藏高原東北緣北祁連造山帶和中祁連微陸塊之間,其石炭紀(jì)—三疊紀(jì)地層之間以整合接觸關(guān)系為主,主要是淺海、海陸交互相至陸相穩(wěn)定型沉積建造。通過系統(tǒng)開展該套地層砂巖碎屑鋯石U-Pb年代學(xué)、砂巖成分Dickinson圖解分析,對(duì)于約束這一時(shí)期沉積物源的構(gòu)造背景、恢復(fù)縫合帶上疊盆地的性質(zhì)、盆地沉積充填模式和古地理面貌,進(jìn)而討論與塔里木、柴達(dá)木的盆地構(gòu)造演化關(guān)系方面均具有重要意義。本次研究采集到北祁連造山帶南緣上二疊統(tǒng)紅泉組、中祁連地塊北緣上二疊統(tǒng)忠什公組和上三疊統(tǒng)尕勒得寺組共3件砂巖樣品,分別對(duì)它們進(jìn)行碎屑鋯石LA-ICP-MS U-Pb測(cè)年,結(jié)果表明具有相似的年齡組成,主要包括2600-2200 Ma、1900-1300Ma、900-800Ma、500-400Ma、290-250Ma等5個(gè)年齡峰。其中2600-2200 Ma、1900-1300Ma兩年齡峰鋯石95顆,推測(cè)來源于自中祁連地塊或華北板塊結(jié)晶基底;900-800Ma年齡峰鋯石11顆,很可能來源于研究區(qū)托來南山片麻狀二長花崗巖巖體及周邊巖體。500-400Ma年齡峰鋯石37顆,來源于北祁連造山帶和中祁連活動(dòng)陸緣在造山期形成的巖漿巖和變質(zhì)巖;290-250Ma年齡峰鋯石46顆,來源于研究區(qū)已隆升且再活化的古祁連山造山帶或東昆侖島弧。石炭紀(jì)—三疊紀(jì)地層中砂巖Dickison三角圖解研究表明,上石炭統(tǒng)羊虎溝組、下-中二疊統(tǒng)江河組砂巖樣品具有較高的石英含量落入循環(huán)造山帶;下-中二疊統(tǒng)大黃溝組、上二疊統(tǒng)紅泉組樣品及忠什公組樣品落入切割弧區(qū)與循環(huán)造山帶的邊界;下-中三疊統(tǒng)下環(huán)倉組與江河組大部分樣品落入循環(huán)造山帶;上三疊統(tǒng)阿塔寺組、尕勒得寺組樣品落入切割弧,這兩套地層中相對(duì)較高的長石含量,可能是物源區(qū)的深成侵入巖已經(jīng)露出地表,并為研究區(qū)的砂巖提供物質(zhì)來源而造成的。最后,將區(qū)域石炭紀(jì)-三疊紀(jì)沉積古地理演化規(guī)律歸納為晚石炭世自南向北超覆、二疊紀(jì)-三疊紀(jì)向南退縮、二疊紀(jì)末向南水位逐漸加深、三疊紀(jì)接受淺�！獮I�！侵蕖訚上噙B續(xù)沉積的過程。
[Abstract]:The study area is located between the northern Qilian orogenic belt and the middle Qilian microcontinent block on the northeast margin of Qinghai-Xizang Plateau. The integrated contact relationship between the Carboniferous and Triassic strata is dominated by the shallow sea, the sea-land intersection and the continental stable sedimentary formation. The study area is located between the northern Qilian orogenic belt and the middle Qilian microcontinent block on the northeast margin of Qinghai-Tibet Plateau. Through the systematic development of U-Pb chronology of sandstone clastic zircon and Dickinson graphic analysis of sandstone composition, the tectonic background of sedimentary source in this period is constrained and the properties of superimposed basins in suture zone are restored. The sedimentary filling model and paleogeographic features of the basin are of great significance in discussing the relationship with the tectonic evolution of the basin in Tarim and Chaidamu. In this study, three sandstone samples were collected from the Upper Permian Hongquan formation on the southern margin of the North Qilian orogenic belt, the Upper Permian Zhongshigong formation and the Upper Triassic Caledesi formation on the northern margin of the Middle Qilian Block. The clastic zircon LA-ICP-MS U-Pb dating was carried out respectively. the results show that they have similar age composition, including 2600 鈮，

本文編號(hào)：2494011