東昆侖東段南坡鬧倉堅溝組地質(zhì)特征、物源屬性與構(gòu)造演化
發(fā)布時間：2018-11-04 18:47
【摘要】：沉積盆地和造山帶為大陸地殼上最為重要的構(gòu)造單元,二者之間的耦合關(guān)系是大陸動力學(xué)研究的熱點。盆地沉積碎屑物則是盆地沉積和構(gòu)造演化的直接證據(jù),更反映了物源區(qū)和沉積盆地的有機(jī)聯(lián)系,因此通過研究盆地沉積碎屑物,進(jìn)而恢復(fù)沉積盆地的沉積環(huán)境以及源區(qū)構(gòu)造背景。本文以分布于東昆侖東段南坡的中三疊統(tǒng)鬧倉堅溝組沉積地層為研究對象,以沉積巖石學(xué)、碎屑組分統(tǒng)計分析、巖石地球化學(xué)及碎屑鋯石同位素年代學(xué)等方法相結(jié)合,綜合研究鬧倉堅溝組沉積特征,分析物源及其構(gòu)造屬性,在此基礎(chǔ)上結(jié)合前人研究成果,建立恢復(fù)東昆侖地區(qū)晚古生代—早中生代古特提斯洋的構(gòu)造演化過程。主要獲得以下進(jìn)展和成果:1、根據(jù)地層巖石組合與沉積環(huán)境的差異,將鬧倉堅溝組由下到上劃分為上下兩個亞組,8個段。其中下亞組(一段—四段)主要為一套碎屑巖夾碳酸鹽巖組合,表現(xiàn)為淺海陸源碎屑陸棚沉積環(huán)境;上亞組(五段—八段)主要為一套碳酸鹽巖夾碎屑巖組合,表現(xiàn)為淺海碳酸鹽巖臺地沉積環(huán)境。說明此時弧前盆地有趨于填滿的勢頭,沉積層序上表現(xiàn)為水深變淺。結(jié)合前人古生物資料、碎屑鋯石年齡信息,晚三疊世科科鄂阿龍巖體的侵入及不整合接觸面(上覆中三疊統(tǒng)希里可特組與鬧倉堅溝組呈微角度不整合接觸,上覆上三疊統(tǒng)八寶山組與鬧倉堅溝組呈角度不整合接觸)四個方面,確定鬧倉堅溝組地層時代為中三疊世(T2)。2、鬧倉堅溝組砂巖巖相學(xué)特征顯示為近源沉積;Dickinson三角圖解顯示鬧倉堅溝組沉積地層的物質(zhì)來源比較復(fù)雜,主要為碰撞造山帶和再旋回造山帶,少數(shù)來自于巖漿弧;砂巖地球化學(xué)顯示鬧倉堅溝組沉積地層的物源區(qū)構(gòu)造背景為大陸島弧。綜合認(rèn)為鬧倉堅溝組物源區(qū)構(gòu)造背景為大陸島弧。3、通過對鬧倉堅溝組碎屑鋯石U-Pb年齡研究表明,樣品11072/15碎屑鋯石年齡值主要有(226~324Ma、372~576Ma、749~936Ma、1010~1092Ma)4個年齡組。鬧倉堅溝組下亞組第二段LA-ICP-MS鋯石U-Pb年齡信息證明鬧倉堅溝組沉積地層的物源主要為東昆侖地區(qū)原特提斯洋和古特提斯洋演化所形成的巖漿弧以及與其相配套的沉積地層。結(jié)合區(qū)域資料和上述分析結(jié)果認(rèn)為鬧倉堅溝組物源區(qū)主要為晚海西—早印支期安第斯型陸緣弧,加里東期巖漿弧次之。4、綜合前人研究成果及區(qū)域構(gòu)造巖漿演化事件,將東昆侖南緣晚古生代—早中生代構(gòu)造演化過程劃分為4個階段:(1)晚泥盆世—中二疊世古特提斯洋殼形成及擴(kuò)張階段;(2)晚二疊世-中三疊世古特提斯洋殼俯沖消減與陸緣弧發(fā)育階段;(3)中三疊世末古特提斯洋閉合與碰撞造山階段;(4)晚三疊世碰撞造山后伸展與侏羅紀(jì)疊加改造階段。
[Abstract]:Sedimentary basins and orogenic belts are the most important tectonic units in continental crust. The sedimentary clastic material of the basin is the direct evidence of the sedimentary and tectonic evolution of the basin, which reflects the organic relation between the source region and the sedimentary basin. Therefore, by studying the sedimentary clastic material of the basin, Then the sedimentary environment and source tectonic setting of the sedimentary basin are restored. In this paper, the sedimentary strata of the middle Triassic Naocangjianggou formation on the south slope of the eastern part of East Kunlun are studied. The methods of sedimentary petrology, statistical analysis of clastic components, geochemistry of rocks and isotopic chronology of detrital zircon are combined. Based on the comprehensive study of the sedimentary characteristics of the Nocangjianggou formation and the analysis of the provenance and its tectonic attributes, the tectonic evolution of the late Paleozoic to early Mesozoic PaleoTethys in the East Kunlun region was established on the basis of previous research results. The main achievements are as follows: 1. According to the difference of stratigraphic rock assemblage and sedimentary environment, the Noucangjiangjianggou formation is divided into two subgroups from the bottom to the top and eight sections. The lower sub-formation (member 1-4) is mainly composed of a set of clastic rock intercalated carbonate rock assemblages, which is characterized by the sedimentary environment of shallow-sea continental clastic shelf. The upper sub-formation (Wuduan-8th formation) is mainly composed of carbonate rock clastic rock assemblage, which is characterized by shallow sea carbonate platform sedimentary environment. The results show that the front arc basin tends to be filled, and the sedimentary sequence is shallow. Based on previous paleontological data and age information of clastic zircon, the intrusive and unconformities of the late Triassic Keke Oallon intrusions and unconformities (the upper and middle Triassic Silicot formation and the Nocangjian Gou formation are in micro-angle unconformable contact with each other). The upper Triassic Babaoshan formation and the Naocang Jiangou formation are in contact with each other at an angle unconformity). The stratigraphic epoch of the Nocangjianggou formation is determined to be the middle Triassic (T2). 2. The lithofacies characteristics of the sandstone of the Nocangjianggou formation are shown to be near source deposits. The Dickinson triangulation shows that the material source of the sedimentary strata of the Nao Cangjian Gou formation is complex, mainly composed of collisional orogenic belt and recirculation orogenic belt, and a few come from magmatic arc. The sandstone geochemistry shows that the source of the sedimentary strata of the Nao Cang Jian Gou formation is continental island arc. It is considered that the tectonic setting of the provenance of the Naocang Jianguo formation is continental island arc. The U-Pb age of the clastic zircon of the Nocangjianggou formation is studied. The results show that the age of 11072 / 15 detrital zircon is mainly in four age groups: (226U 324Ma-372MN 7496Ma) 936Ma (101092Ma). The LA-ICP-MS zircon U-Pb age information of the second member of the lower subformation of the Noucangjinggou formation proves that the sedimentary strata of the Naocang Jiangou formation are mainly derived from magmatic arcs formed by the evolution of the original Tethys and paleoTethys oceans in the East Kunlun region and the relationship between the The associated sedimentary strata. Based on the regional data and the above analysis results, it is concluded that the provenance of the Nocangjianggou formation is mainly a late Hercynian-early Indosinian Andean marginal arc, followed by the Caledonian magmatic arc. 4. The results of previous studies and the regional tectonic magmatic evolution events are synthesised. The late Paleozoic to early Mesozoic tectonic evolution processes in the southern margin of East Kunlun were divided into four stages: (1) the late Devonian to the Middle Permian Paleo-Tethys oceanic crust formation and extension; (2) the late Permian-Middle Triassic PaleoTethys ocean crust subduction and continental margin arc development stage, (3) the late Middle Triassic PaleoTethys ocean closure and collision orogenic stage; (4) the late Triassic post-collision orogenic extension and Jurassic superimposition.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P548
本文編號：2310818
[Abstract]:Sedimentary basins and orogenic belts are the most important tectonic units in continental crust. The sedimentary clastic material of the basin is the direct evidence of the sedimentary and tectonic evolution of the basin, which reflects the organic relation between the source region and the sedimentary basin. Therefore, by studying the sedimentary clastic material of the basin, Then the sedimentary environment and source tectonic setting of the sedimentary basin are restored. In this paper, the sedimentary strata of the middle Triassic Naocangjianggou formation on the south slope of the eastern part of East Kunlun are studied. The methods of sedimentary petrology, statistical analysis of clastic components, geochemistry of rocks and isotopic chronology of detrital zircon are combined. Based on the comprehensive study of the sedimentary characteristics of the Nocangjianggou formation and the analysis of the provenance and its tectonic attributes, the tectonic evolution of the late Paleozoic to early Mesozoic PaleoTethys in the East Kunlun region was established on the basis of previous research results. The main achievements are as follows: 1. According to the difference of stratigraphic rock assemblage and sedimentary environment, the Noucangjiangjianggou formation is divided into two subgroups from the bottom to the top and eight sections. The lower sub-formation (member 1-4) is mainly composed of a set of clastic rock intercalated carbonate rock assemblages, which is characterized by the sedimentary environment of shallow-sea continental clastic shelf. The upper sub-formation (Wuduan-8th formation) is mainly composed of carbonate rock clastic rock assemblage, which is characterized by shallow sea carbonate platform sedimentary environment. The results show that the front arc basin tends to be filled, and the sedimentary sequence is shallow. Based on previous paleontological data and age information of clastic zircon, the intrusive and unconformities of the late Triassic Keke Oallon intrusions and unconformities (the upper and middle Triassic Silicot formation and the Nocangjian Gou formation are in micro-angle unconformable contact with each other). The upper Triassic Babaoshan formation and the Naocang Jiangou formation are in contact with each other at an angle unconformity). The stratigraphic epoch of the Nocangjianggou formation is determined to be the middle Triassic (T2). 2. The lithofacies characteristics of the sandstone of the Nocangjianggou formation are shown to be near source deposits. The Dickinson triangulation shows that the material source of the sedimentary strata of the Nao Cangjian Gou formation is complex, mainly composed of collisional orogenic belt and recirculation orogenic belt, and a few come from magmatic arc. The sandstone geochemistry shows that the source of the sedimentary strata of the Nao Cang Jian Gou formation is continental island arc. It is considered that the tectonic setting of the provenance of the Naocang Jianguo formation is continental island arc. The U-Pb age of the clastic zircon of the Nocangjianggou formation is studied. The results show that the age of 11072 / 15 detrital zircon is mainly in four age groups: (226U 324Ma-372MN 7496Ma) 936Ma (101092Ma). The LA-ICP-MS zircon U-Pb age information of the second member of the lower subformation of the Noucangjinggou formation proves that the sedimentary strata of the Naocang Jiangou formation are mainly derived from magmatic arcs formed by the evolution of the original Tethys and paleoTethys oceans in the East Kunlun region and the relationship between the The associated sedimentary strata. Based on the regional data and the above analysis results, it is concluded that the provenance of the Nocangjianggou formation is mainly a late Hercynian-early Indosinian Andean marginal arc, followed by the Caledonian magmatic arc. 4. The results of previous studies and the regional tectonic magmatic evolution events are synthesised. The late Paleozoic to early Mesozoic tectonic evolution processes in the southern margin of East Kunlun were divided into four stages: (1) the late Devonian to the Middle Permian Paleo-Tethys oceanic crust formation and extension; (2) the late Permian-Middle Triassic PaleoTethys ocean crust subduction and continental margin arc development stage, (3) the late Middle Triassic PaleoTethys ocean closure and collision orogenic stage; (4) the late Triassic post-collision orogenic extension and Jurassic superimposition.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P548
【相似文獻(xiàn)】
相關(guān)期刊論文 前2條
1 王惠基,祁良志;青海三疊紀(jì)腹足類化石[J];古生物學(xué)報;1986年01期
2 ;[J];;年期
相關(guān)碩士學(xué)位論文 前1條
1 陳偉男;東昆侖東段南坡鬧倉堅溝組地質(zhì)特征、物源屬性與構(gòu)造演化[D];長安大學(xué);2015年
，本文編號：2310818
本文鏈接：http://sikaile.net/kejilunwen/diqiudizhi/2310818.html
最近更新
教材專著
