本文關(guān)鍵詞：福建東南沿海泉州地區(qū)晚中生代巖漿巖年代學(xué)與地球化學(xué)　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2015年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 福建東南沿海 晚中生代 巖漿巖 年代學(xué) 地球化學(xué)

【摘要】：福建省位于我國(guó)大陸東南部,是歐亞與太平洋板塊的交匯部位。其構(gòu)造位置上處在華夏地塊東南緣,加里東期以來(lái)發(fā)育有大量巖漿巖,特別是面積廣闊的中生代各類型花崗巖。區(qū)域內(nèi)構(gòu)造環(huán)境獨(dú)特,具有復(fù)雜的地球動(dòng)力學(xué)演化史。對(duì)這一地區(qū)巖漿巖巖石成因、構(gòu)造-巖漿演化歷史的研究,對(duì)最終揭示沿海地區(qū)乃至華南陸塊構(gòu)造-巖漿演化歷史有著重要的參考意義。泉州地區(qū)位于福建省東南沿海,出露巖漿巖以花崗巖為主,巖體呈巖基、巖株?duì)钋治挥谙氯B系、侏羅紀(jì)、上第三系和第四系地層中,并在緊鄰海岸線的區(qū)域發(fā)育有中基性脈巖,脈巖沿解理與脆弱部位侵位于花崗巖巖基中。經(jīng)鋯石LA-ICP-MS年代學(xué)測(cè)試,泉州地區(qū)巖漿作用可分為晚侏羅-早白堊世(162~141Ma)、早白堊-晚白堊世(132~96Ma)、晚白堊世(96~90Ma)三個(gè)階段。晚侏羅-早白堊世巖漿巖分布于距離海岸線最遠(yuǎn)的地區(qū),巖性以高鉀鈣堿性的偏鋁質(zhì)花崗巖為主;早白堊-晚白堊世巖漿巖發(fā)育于距離海岸線較近的地區(qū),巖性以高鉀鈣堿性、偏鋁質(zhì)花崗巖為主;晚白堊世巖漿巖則主要為中-高鉀鈣堿性的鎂鐵質(zhì)脈巖以及少量的高鉀、偏鋁質(zhì)黑云母花崗巖。在成因及巖石類型上,泉州地區(qū)花崗巖樣品均為I-型花崗巖,部分表現(xiàn)出高分異特征,并普遍富集大離子親石元素、虧損高場(chǎng)強(qiáng)元素的,表現(xiàn)出一定的島弧性質(zhì)。鋯石Hf以及全巖Sr、Nd同位素指示其成巖過(guò)程中存在不同程度的幔源物質(zhì)注入,并整體向沿海方向幔源物質(zhì)貢獻(xiàn)量增加,結(jié)合其多峰的同位素地殼模式年齡特征表明這一地區(qū)曾存在廣泛的幔殼間相互作用。脈巖樣品顯示出與島弧有關(guān)的微量元素性質(zhì)的同時(shí),還兼有大陸邊緣裂谷的特點(diǎn),源區(qū)具有EMI、EMII與虧損地幔的多源混合特征。年代學(xué)測(cè)試結(jié)果則顯示出其產(chǎn)出時(shí)間與區(qū)域上100~110Ma、85~95Ma的大范圍伸展事件相吻合。結(jié)合區(qū)域上已有研究成果,福建泉州地區(qū)晚侏羅-晚白堊時(shí)期可能先后經(jīng)歷了,晚侏羅-早白堊世特提斯構(gòu)造域與古太平洋俯沖構(gòu)造域聯(lián)合作用及體制轉(zhuǎn)換;早白堊-晚白堊世由俯沖引起的大范圍伸展與幔源巖漿底侵以及俯沖后期發(fā)生的板片后撤與板片斷離事件;晚白堊世俯沖-拉張構(gòu)造體制過(guò)渡階段。本文的研究也為進(jìn)一步描繪福建沿海地區(qū)晚中生代構(gòu)造巖漿演化歷史提供了新的佐證。
[Abstract]:Fujian Province is located in the southeastern part of the mainland of China and is the intersection of Eurasian and Pacific plates. Its tectonic position is located in the southeastern margin of the Cathaysian block and a large number of magmatic rocks have developed since Caledonian. Especially the broad Mesozoic granites of various types. The tectonic environment in the region is unique and has a complex geodynamic evolution history. The study on the genesis of magmatic rocks and the history of tectonic-magmatic evolution in this area. It has important reference significance to reveal the history of tectonic-magmatic evolution in coastal area and even South China. Quanzhou area is located in the southeast coast of Fujian Province. The exposed magmatic rocks are mainly granite and the rock mass is rock base. The intrusions are located in the Lower Triassic, Jurassic, Eogene and Quaternary strata, and there are meso-basic dikes in the area adjacent to the shoreline. The dike rocks are transgressive along the cleavage and fragile position in the granitic bedrock. The magmatism in Quanzhou area can be divided into late Jurassic-early Cretaceous Y162U 141Maby zircon LA-ICP-MS chronology test. The late Jurassic-early Cretaceous magmatic rocks are distributed in the areas farthest from the coastline. The lithology is dominated by high potassium calc-alkaline metaaluminous granite; The early Cretaceous and late Cretaceous magmatic rocks developed near the shoreline. The lithology was characterized by high potassium calc-alkaline and metaaluminous granites. The late Cretaceous magmatic rocks are mainly medium-high calc-alkaline mafic dikes and a small amount of high-potassium and metamorphic biotite granites. In terms of genesis and rock types, the samples of granites in Quanzhou area are all I-type granites. Some of them are characterized by high differentiation, large ion lithophile elements, and depleted high field strength elements, which show some island arc properties, zircon HF and whole rock Sr. ND isotopes indicate that there are different degrees of mantle source material injection in the diagenetic process, and the contribution of mantle source material to the coastal direction is increasing as a whole. The age characteristics of its multi-peak isotopic crustal model indicate that there has been extensive interaction between mantle and crust in this area. The dike samples show microelement properties related to island arc at the same time. It also has the characteristics of continental marginal rift, and the source region has the characteristics of multi-source mixing of EMI-EMII and depleted mantle. The geochronological test results show that the occurrence time of EMI-EMII is 100 ~ 110Ma in the region. The extensive extensional events of 850.95 Ma coincided with each other. Combined with the research results in the region, the late Jurassic-late Cretaceous period in Quanzhou area, Fujian Province, may have been experienced successively. Late Jurassic-early Cretaceous Tethys tectonic domain and paleo-Pacific subduction tectonic domain; Early Cretaceous to late Cretaceous by subduction caused by the large-scale extension and mantle magma submersion, as well as the late subduction of plate retreat and fragment separation events; The late Cretaceous subduction and extensional tectonic system transition stage. The study in this paper also provides new evidence for describing the history of late Mesozoic tectonic magma evolution in Fujian coastal area.
【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：P588.1;P597.3

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