本文選題：巴顏喀拉 + 構(gòu)造變形��； 參考：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：分布于青藏高原腹地北東部的可可西里—巴顏喀拉三疊紀(jì)沉積盆地,其分布范圍北以木孜塔格—東昆南—阿尼瑪卿斷裂帶為界,南至西金烏蘭—玉樹—金沙江斷裂帶,東以龍門山推覆構(gòu)造為限,呈現(xiàn)出巨型倒三角形區(qū)域。巴顏喀拉盆地除西部和東部部分地區(qū)出露二疊系,其他部分地區(qū)出露侏羅—第四系外,大部分地區(qū)均被巨厚的三疊系所覆蓋,其中蘊(yùn)藏著許多地質(zhì)信息,從而成為了國內(nèi)一塊神秘的區(qū)域,并引起了中外學(xué)者的極大關(guān)注,被稱為“中國的百慕大”。本文以共和-玉樹剖面為基礎(chǔ),對巴顏喀拉山群進(jìn)行了構(gòu)造變形特征研究,將研究區(qū)從南至北劃分為三個構(gòu)造變形分帶,分別為緊閉褶皺沖斷帶、寬緩褶皺沖斷帶和斜歪傾伏褶皺沖斷帶。結(jié)合野外現(xiàn)象和室內(nèi)研究分析,識別了3期主要的構(gòu)造變形:①俯沖擠壓變形,以緊閉褶皺和逆沖、走滑斷裂為特征,可同區(qū)域上中晚三疊世揚(yáng)子板塊與包括柴達(dá)木板塊在內(nèi)的華北板塊俯沖匯聚事件相配套,并奠定了巴顏喀拉山群主體NWW-SEE向的褶皺-沖斷的構(gòu)造格架;②左行走滑剪切變形,以疊加在早期片理面之傾豎褶皺、劈理化作用為特征,可能為巴顏喀拉地塊與揚(yáng)子板塊的NE向斜向俯沖所致;③脆性斷裂構(gòu)造,以發(fā)育脆性正斷層為特征,可同青藏高原的快速隆升相配套,變形特征上顯示一系列的寬緩褶皺被脆性斷裂所切斷。在此基礎(chǔ)之上,進(jìn)一步分別對各分帶的沉積、碎屑成分及古水流、碎屑鋯石年齡信息等特征進(jìn)行了詳細(xì)的對比,結(jié)果顯示本區(qū)的三個變形分帶在層位上、成分變化以及鋯石年齡頻譜上均顯示一定的規(guī)律性或者相似性,僅表現(xiàn)在構(gòu)造外貌上有所不同,因此,我們認(rèn)為其主要是在同一構(gòu)造作用下形成的不同構(gòu)造組合樣式。而區(qū)域上中晚三疊世揚(yáng)子板塊與包括柴達(dá)木板塊在內(nèi)的華北板塊俯沖匯聚可能是奠定巴顏喀拉山群主體NWW-SEE向的褶皺—沖斷構(gòu)造格架的主要構(gòu)造作用,而之后的左行走滑變形以及晚期的斷裂構(gòu)造活動僅僅是對本區(qū)構(gòu)造格架的微調(diào)作用。在綜合研究前人古水流資料成果的基礎(chǔ)上,作者結(jié)合砂巖碎屑成分統(tǒng)計分析發(fā)現(xiàn),巴顏喀拉盆地從邊緣至盆地中心具蛇綠混雜巖—濁積巖—深海盆地的變化規(guī)律。盆地中北部的陸源碎屑物主要來自盆地北部兩條造山帶:昆侖造山帶和秦嶺造山帶,前者是主要的物質(zhì)來源,也有來自柴達(dá)木板塊的部分物源。巴顏喀拉盆地存在發(fā)散式古水流,總體方向為北東至南西向,基本上與殘留洋盆古水流樣式一致。巴顏喀拉盆地在巴顏喀拉山群1段沉積時,為海陸相間的地理格局,到2、3段時,海盆達(dá)到最大,沉積中心有向北推移的趨勢,4段時,海盆逐漸縮小,呈現(xiàn)出由東向西逐漸消退的趨勢,并發(fā)育了兩個沉積中心。
[Abstract]:The Khoxili-Bayankala Triassic sedimentary basin in the eastern part of the hinterland of the Qinghai-Xizang Plateau is bounded by the Muzitage-East Kunnan-Animachin fault zone in the north, and the Xijin Wu Lan-Yushu-Jinsha River fault zone in the south. To the east, Longmen Mountain nappe structure as the limit, showing a giant inverted triangle area. Except for the Permian in the western and eastern parts of the Bayan Kara basin, and the other parts of the basin, most of them are covered by the extremely thick Triassic system, which contains a lot of geological information. Thus became a mysterious region in China, and attracted great attention of Chinese and foreign scholars, known as "Bermuda of China." Based on the Gong-Yushu section, the structural deformation characteristics of Bayan Kara Mountain Group are studied in this paper. The study area is divided from south to north into three tectonic deformation zones, namely, closed fold thrust zone. Wide gentle fold thrust zone and oblique tilting fold thrust zone. Combined with field phenomena and laboratory analysis, the main tectonic deformation: 1 subduction and compression deformation in three periods are identified, which are characterized by tight fold, thrust and strike-slip faults. It can be matched with the events of subduction and convergence of North China plate, including Qaidam plate, in the Middle and late Triassic of the region, and establishes the fold-thrust tectonic framework of the Bayan Kara Mountain Group in the direction of NWW-SEE direction and the shear deformation of the left strike-slip. Characterized by the dipping vertical fold and cleavage action on the early facies, it may be a brittle fault structure caused by the NE syncline subduction of the Bayan Kara block and the Yangtze plate, which is characterized by the development of the brittle normal fault. It can be matched with the rapid uplift of the Qinghai-Xizang Plateau. The deformation characteristics show that a series of wide and slow folds are cut off by brittle faults. On this basis, the depositional, clastic composition, paleocurrent and age information of zircon in each zone are compared in detail. The results show that the three deformation zones in this area are on the horizon. The composition changes and the zircon age spectrum show certain regularity or similarity, but only show different tectonic appearance. Therefore, we think that they are mainly formed under the same tectonic action of different tectonic combination style. The subduction convergence of the Yangtze plate and the North China plate, including the Qaidam plate, may be the main tectonic framework of the NWW-SEE trending fold thrust tectonic framework in the main body of the Bayan Kara Mountain Group, and the subduction and convergence of the Yangtze plate and the North China plate, including the Qaidam plate, may form the main tectonic framework of the NWW-SEE direction of the Bayan Kara Mountain Group. The subsequent left strike-slip deformation and late fault tectonic activity are only fine-tuned to the tectonic framework in this area. On the basis of synthetically studying the data of paleocurrent, combined with the statistical analysis of sandstone clastic composition, the author found that there are ophiolite, turbidite and deep-sea basins from the margin to the center of the basin in Bayan Kara Basin. The continental clastic material in the central and northern part of the basin mainly comes from two orogenic belts in the northern part of the basin: the Kunlun orogenic belt and the Qinling orogenic belt. The former is the main material source and the other is from the Qaidam plate. There are divergent paleocurrent in Bayankala basin, the general direction is from north east to south west, which is basically consistent with the paleocurrent pattern of residual ocean basin. The Bayankala basin was formed in the first member of the Bayan Kara Group during the deposition of the first member of the Bayan Kara Group. By the time of formation 2 and 3, the basin reached its maximum, and the sedimentary center gradually shrank when the sedimentary center tended to move northward to the fourth member. It shows a trend of fading from east to west, and develops two sedimentary centers.
【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】：P548

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 張克信,黃繼春,殷鴻福,王國燦,王永標(biāo),馮慶來,田軍;Application of radiolarians and other fossils in non-Smith strata——Exemplified by the A'nyemaqen melange belt in East Kunlun Mts.[J];Science in China(Series D:Earth Sciences);2000年04期

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本文編號：1919852