本文關鍵詞：新疆西準噶爾地區(qū)古生代巖漿活動的年代學和地球化學研究　出處：《中國地質(zhì)大學》2016年博士論文　論文類型：學位論文

  更多相關文章： 西準噶爾 古生代 巖漿巖 年代學 地球化學 LA-ICP-MS 鋯石U-Pb測年 Hf同位素

【摘要】：西準噶爾地區(qū)經(jīng)歷了多期次、多階段長期而復雜的構造地質(zhì)演化,同時伴隨著大量的花崗質(zhì)巖漿活動。各期巖漿巖的成因、物源涉及西準噶爾造山帶的形成,特別是各期次花崗巖漿活動的地球動力學過程與演化。本文選擇西準噶爾地區(qū)古生代的巖漿巖(火山巖和侵入巖),重點對有代表性的巖體進行了巖石學、地球化學、鋯石形態(tài)學、鋯石LA-ICP-MS U-Pb年代學和鋯石Hf同位素地球化學等分析等,厘定了各期構造事件的時限,劃分了巖漿巖的活動期次,確定了巖漿巖成因,反演了西準噶爾造山帶構造演化過程。運用鋯石LA-ICP-MS U-Pb定年方法,對研究區(qū)內(nèi)7個花崗巖體進行了精細的年代學研究,其中,蘇根薩拉花崗巖體的年齡為415.6±1.1Ma,為晚志留世。玉什喀臘輝長巖體的年齡為364±1Ma,為晚泥盆世。黑子勒塔吾丁浩熱石英二長閃長巖體的年齡為364.7±3.0Ma,為晚泥盆世。木斯島山二長花崗巖體的年齡為335.9±0.9Ma,為早石炭世。加爾路阿甫花崗斑巖體的年齡為305±2Ma,為晚石炭世。闊依塔斯閃長巖體的年齡為297±2Ma,為晚石炭世。恰其海鉀長花崗巖體的年齡為280.1±3.2Ma,為早二疊世。確認了各期次花崗巖的侵入時代,為認識西準噶爾構造巖漿演化提供了高精度的年代學依據(jù)。結合前人研究成果,將研究區(qū)內(nèi)巖漿巖的期次劃分為4個階段：早志留世-早泥盆世(436-405Ma)、早石炭世(350-320Ma)、晚石炭世-早二疊世(318-270Ma)和中晚二疊世(270-263Ma)。巖漿巖在時空分布上具有明顯的規(guī)律性,其形成時代具有南北老,中間新的變化規(guī)律。侵入巖的巖石地球化學研究表明,研究區(qū)各階段巖體主要為A型和I型花崗巖。謝米斯臺山西段花崗巖巖石類型為A2型花崗巖和堿性弱過鋁質(zhì)分異I型花崗巖。早石炭世花崗巖以I型為主,主要分布于薩吾爾地區(qū),呈帶狀分布,可能形成于陸殼俯沖的構造背景下,晚石炭世-早二疊世花崗巖以A型為主,呈面狀分布,具有堿性和準鋁質(zhì)特征,可能為俯沖有關的流體交代的產(chǎn)物,部分巖漿源區(qū)具有明顯的弧巖漿活動特點,可能形成于碰撞后伸展環(huán)境中。晚泥盆世玉什喀臘輝長巖體為俯沖流體交代虧損的巖石圈地幔形成,巖漿在上升過程中沒有遭受地殼物質(zhì)的混染。早二疊世基性侵入巖的源區(qū)中既有俯沖消減的印跡,又有地幔組分的參與,可能是被俯沖板片或消減沉積物所釋放的流體交代后的地幔橄欖巖部分熔融的產(chǎn)物。新獲得了西準噶爾地區(qū)7個侵入巖鋯石Hf同位素組成,結果表明,區(qū)內(nèi)各時期侵入巖體具有相似的鋯石Hf同位素,它們均具正的εHf(t)值,且正值較高,指示各期花崗巖主要為新生陸殼部分熔融的產(chǎn)物,反映在西準噶爾地區(qū)從中元古到早古生代的奧陶紀持續(xù)有新生陸殼形成。這與整個中亞造山帶從新元古代以來持續(xù)形成新的陸殼和發(fā)生多起弧-陸碰撞拼貼、大陸增生是吻合的。在上述研究的基礎之上,結合區(qū)域地質(zhì)背景和西準噶爾造山帶構造演化特征,討論了古亞洲洋閉合的時限和后碰撞作用的時限。研究表明,該區(qū)為多次碰撞、多次消減,洋盆是形成一個、消減一個,再形成一個、再消減一個,相繼出現(xiàn),相繼消減。古亞洲洋的范圍很廣,可能每個區(qū)域閉合的時間不盡相同。本文推斷在西準噶爾北部地區(qū)(額爾齊斯縫合帶附近),晚泥盆世洋陸俯沖事件已基本結束,古亞洲洋閉合的時間不早于364Ma。對于后碰撞作用的時限,結合區(qū)域地質(zhì)資料,本文推測西準噶爾地區(qū)后碰撞深成巖漿活動是從早石炭世開始,于早二疊末期結束,即后碰撞深成巖漿活動發(fā)生在340-270Ma之間。通過對巖漿巖巖石成因、Hf同位素示蹤與構造演化關系的研究,認為古生代特別是晚古生代是中亞造山帶大陸地殼增生的重要時期。增生方式包括了與俯沖作用有關的側向增生,還包括與幔源巖漿底侵有關的垂向增生,大陸地殼增生是一個多階段多旋回的過程,貫穿于中亞造山帶形成演化的整個過程。
[Abstract]:The western Junggar region has experienced a long and complicated tectonic and geological evolution with multiple stages and multiple stages, and accompanied by a large number of granitic magmatism. The genesis and source of the magmatic rocks in each period involve the formation of the western Junggar orogenic belt, especially the geodynamic process and evolution of the granitic magma activities of each period. This choice of Paleozoic in Western Junggar magmatite (volcano rock and intrusive rock), focusing on the petrology, geochemistry, zircon morphology, zircon LA-ICP-MS U-Pb geochronology and Hf isotope geochemistry analysis of representative rock bodies, determine the different tectonic events of the time, the division of magmatite activity second, to determine the origin of magmatite, West Junggar orogenic belt tectonic evolution inversion. Based on zircon LA-ICP-MS U-Pb dating method, 7 granitoids in the study area were studied in fine chronology. The age of the Sugang Sara granite is 415.6 + 1.1Ma, which is late Silurian. Jade Shenka wax gabbro age was 364 + 1Ma, late devonian. Wu Ding Hao Rotha sunspot two long hot quartz diorite age was 364.7 + 3.0Ma, late devonian. Jiamusi two long island mountain granite age was 335.9 + 0.9Ma, early carboniferous. Garr Road, Afu granitic porphyry, age 305 + 2Ma, the late carboniferous. The age of the Kuo TASI diorite body is 297 + 2Ma, which is late Carboniferous. The age of the pluton granite pluton in the Qitai sea is 280.1 + 3.2Ma, which is early Permian. The intrusive age of each period granite has been confirmed, which provides a high precise chronological basis for understanding the evolution of tectonic magma in Western Junggar. Combined with previous studies, the stages of magmatic rocks in the study area are divided into 4 stages: the Early Silurian Early Devonian (436-405Ma), the Early Carboniferous (350-320Ma), the Late Carboniferous Early Permian (318-270Ma) and the middle Late Permian (270-263Ma). The magmatic rocks have obvious regularity in the spatial and temporal distribution, and the age of its formation has a new law of change in the north and the South and in the middle. The rock geochemical study of intrusive rocks shows that the rock mass in each stage of the study area is mainly A and I type granite. The granite rock types in the western section of Semis Taishan are type A2 granite and alkaline weak peraluminous I type granite. Early Carboniferous granite is dominated by I, mainly distributed in the Sawuer region, zonal distribution, tectonic background may be formed in the continental subduction, the Late Carboniferous and Early Permian granites are mainly of A type, a planar distribution, are basic and metaluminous characteristics, may have related products of subduction fluid metasomatism the arc magmatism has the obvious characteristics of some magmatic source, probably formed in a post collisional extensional environment. The middle Late Devonian formation of jade Shenka wax gabbro in the subduction metasomatism depleted lithospheric mantle, magma has not been contaminated by crustal materials during ascending. Both subduction imprint source area as early as two fold mafic intrusive rocks, and mantle components involved, may be a product of mantle peridotite partial melting fluid metasomatism released by the subducting slab or subducted sediments after the. To get the new West Junggar area 7 intrusive rocks zircon Hf isotopic composition, the results show that the zircon Hf isotopic has similar intrusions in each period in the region, they are epsilon Hf positive (T) value, and when higher, indicating the granite is mainly a product of partial melting of continental crust new, reflected in the West Junggar area from Middle Proterozoic to early Paleozoic Ordovician continuous new continental crust formation. This is in accordance with the whole Central Asian orogenic belt, which has been formed from the Neoproterozoic Era to the new continental crust and many arc - land collision collages and continental hyperplasia. On the basis of the above research, combined with the regional geological background and the structural evolution characteristics of the West Junggar orogenic belt, the time limit for the closure of the Asian Asian Ocean and the time limit for post collisional action are discussed. Study shows that this area is many collisions and multiple cuts, is the formation of a basin, a cut, and then form a cut, one appeared one after another, have been cut. The ancient Asian Ocean has a wide range, and it may be different for each area to close. This paper concluded that in the northern region of Western Junggar (near Eerqisi suture), Late Devonian oceanic subduction event has been completed, the closure of the paleo Asian Ocean time not earlier than 364Ma. For the time limit of post collisional interaction, combined with regional geological data, we conclude that the post collisional deep plutonic activity in the western Junggar area started from the Early Carboniferous and ended at the early two stage. That is, post collisional deep magmatic activity occurs between 340-270Ma. Based on the study of petrogenesis, Hf isotope tracing and tectonic evolution of magmatic rocks, it is considered that Palaeozoic, especially late Paleozoic, is an important period of continental crustal accretion in the Central Asian orogenic belt. The way of proliferation includes lateral proliferation related to subduction, and vertical hyperplasia related to mantle derived magma underplating. Continental crust proliferation is a multi stage and multi cycle process, which runs through the whole process of the formation and evolution of the Central Asian orogenic belt.
【學位授予單位】：中國地質(zhì)大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：P597.3;P588.11

【參考文獻】

相關期刊論文 前10條

1 靳松;榮桂林;張兆yN;李天剛;彭朝暉;吳立昂;;新疆西準噶爾瑪依勒山地區(qū)闊依塔斯雜巖體地球化學特征及鋯石U-Pb年齡[J];中國地質(zhì);2016年01期

2 張達玉;周濤發(fā);袁峰;鄧宇峰;許超;張若飛;李鵬;王金林;;西準噶爾薩吾爾地區(qū)早古生代火山巖的發(fā)現(xiàn)及其意義[J];巖石學報;2015年02期

3 李平;王洪亮;徐學義;陳雋璐;過磊;奚仁剛;;西準噶爾早泥盆世馬拉蘇組火山巖巖石成因研究[J];巖石學報;2014年12期

4 徐學義;李榮社;陳雋璐;馬中平;李智佩;王洪亮;白建科;唐卓;;新疆北部古生代構造演化的幾點認識[J];巖石學報;2014年06期

5 高睿;肖龍;王國燦;賀新星;楊剛;鄢圣武;;西準噶爾晚古生代巖漿活動和構造背景[J];巖石學報;2013年10期

6 郭召杰;;新疆北部大地構造研究中幾個問題的評述——兼論地質(zhì)圖在區(qū)域構造研究中的重要意義[J];地質(zhì)通報;2012年07期

7 尹繼元;袁超;王毓婧;龍曉平;關義立;;新疆西準噶爾晚古生代大地構造演化的巖漿活動記錄[J];大地構造與成礦學;2011年02期

8 童英;王濤;洪大衛(wèi);韓寶福;張建軍;史興俊;王超;;北疆及鄰區(qū)石炭-二疊紀花崗巖時空分布特征及其構造意義[J];巖石礦物學雜志;2010年06期

9 何世平;李榮社;王超;于浦生;辜平陽;時超;;祁連山西段甘肅肅北地區(qū)北大河巖群片麻狀斜長角閃巖的形成時代[J];地質(zhì)通報;2010年09期

10 李永軍;佟麗莉;張兵;劉靜;張?zhí)炖^;王軍年;;論西準噶爾石炭系希貝庫拉斯組與包古圖組的新老關系[J];新疆地質(zhì);2010年02期

，

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