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  本文關鍵詞： I-A型復合花崗巖 年代學 地球化學 巖石成因 福州復式巖體　出處：《中國地質(zhì)大學(北京)》2015年碩士論文　論文類型：學位論文

【摘要】：華南沿海地區(qū)發(fā)育有大量的中生代花崗巖,雖然這是我國花崗巖研究程度較高的地區(qū)之一,但是對于該時期復式巖體的研究并不是很多,其巖石成因和構(gòu)造背景一直存在較大爭議。本文報道了福州復式巖體花崗巖的巖石學、鋯石U-Pb年代學、鋯石微量元素、Hf同位素和全巖主、微量地球化學的研究結(jié)果,試圖為深入探討該時期的巖石成因提供新資料。福州復式巖體的花崗巖主要分為鈣堿性和堿性兩大類,分別采自于福州巖體、丹陽巖體和魁岐巖體,巖石類型主要為:黑云母鉀長花崗巖,二長花崗巖和堿性花崗巖。LA-ICP-MS鋯石U-Pb定年結(jié)果表明:福州巖體和丹陽巖體形成的年齡約為:106 Ma和111 Ma、101Ma,是早白堊世多期次巖漿活動作用的產(chǎn)物;魁岐巖體形成的年齡為:93Ma、95Ma,是晚白堊世巖漿活動的產(chǎn)物。鋯石微量的差異可以推斷早白堊世鈣堿性花崗巖為I型花崗巖,晚白堊世堿性花崗巖為A型花崗巖,構(gòu)成了I-A型巖石系列。研究區(qū)內(nèi)的巖石樣品均具有Eu負異常、LREE富集和HREE虧損的特征,均顯示Rb、Th、U、K、Pb等大離子親石元素相對富集,Ba、Sr以及高場強元素Nb、Ta、P、Ti相對虧損。本文I型花崗巖的輕重稀土分餾程度較之A型花崗巖明顯,LREE/HREE比值較大,A型花崗巖的負銪異常比I型花崗巖明顯,同時也佐證了前面I-A型巖石系列的推測。鋯石Hf同位素的結(jié)果表明,I型花崗巖的εHf(t)值由負到正,地殼模式年齡表明花崗質(zhì)巖漿源巖來自于新元古代古老地殼的部分熔融,并有少量的地幔組分卷入。A型花崗巖樣品εHf(t)值為正,地殼模式年齡指示花崗質(zhì)巖漿源巖來自于新元古代古老地殼的部分熔融,并有大量幔源組分的混入。福州復式巖體中I-A型花崗巖具有相同的源區(qū),其形成的差異主要是構(gòu)造環(huán)境的變遷、幔源巖漿的加入以及巖漿分異演化多種因素綜合作用的結(jié)果。
[Abstract]:There are a large number of Mesozoic granites developed in the coastal areas of South China. Although this is one of the areas with a high degree of granite research in China, there are not many studies on the composite rock mass in this period. The petrology, zircon U-Pb geochronology, zircon trace element HF isotope and the whole rock host of the complex granites in Fuzhou are reported in this paper. The results of trace geochemistry try to provide new data for the further study of the petrogenesis of this period. The granites of Fuzhou complex rock body are mainly divided into two types: calc-alkaline and alkaline, which were collected from Fuzhou rock body respectively. Danyang and Qui-qi rock bodies, the main rock types are: biotite potassium feldspar granite. The zircon U-Pb dating results of the monzogranites and alkaline granites show that the ages of formation of Fuzhou and Danyang pluton are about 10 ~ 106 Ma and 111 Ma. 101 Ma was the product of multistage magmatism in early Cretaceous; The age of formation of Kui-qi rock body is: 93 Ma-95 Ma, which is the product of late Cretaceous magmatic activity. The difference of trace zircon can be inferred that the early Cretaceous calc-alkaline granite is I-type granite. The late Cretaceous alkaline granites are A-type granites, forming I-A type rock series. The samples in the study area are characterized by negative EU anomaly LREE enrichment and HREE depletion, indicating RB. The large ion lithophile elements such as Th _ (+) U _ (U) K _ (+) Pb are relatively enriched in Ba-Ba _ (Sr) and the high field strength element (NB ~ (+) Ta _ (P)). The REE / hree ratio of the I-type granite is larger than that of the A-type granite, and the negative europium anomaly of the A-type granite is more obvious than that of the I-type granite. The results of zircon HF isotopes indicate that the 蔚 Hft values of the I-A type granites vary from negative to positive. The crustal model age indicates that the granitic magmatic source rocks originated from the partial melting of the Neoproterozoic ancient crust, and a small amount of mantle components are involved in the sample of .A-type granite. The crustal model age indicates that the granitic magmatic source rocks are derived from the partial melting of the Neoproterozoic ancient crust and are mixed with a large number of mantle-derived components. The I-A type granites in the Fuzhou complex have the same source area. The difference of formation is mainly caused by the changes of tectonic environment, the addition of mantle magma and the comprehensive action of many factors of magmatic differentiation and evolution.
【學位授予單位】：中國地質(zhì)大學(北京)
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P588.121

【參考文獻】

相關期刊論文 前10條

1 柏道遠;黃建中;李金冬;王先輝;馬鐵球;張曉陽;陳必河;;華南中生代構(gòu)造演化過程的多地質(zhì)要素約束——湘東南及湘粵贛邊區(qū)中生代地質(zhì)研究的啟示[J];大地構(gòu)造與成礦學;2007年01期

2 邱檢生,王德滋,蟹澤聰史,BrentI A McInnes;福建沿海鋁質(zhì)A型花崗巖的地球化學及巖石成因[J];地球化學;2000年04期

3 周金城,陳榮;閩東南晚中生代殼幔作用地球化學[J];地球化學;2001年06期

4 周怵若,楊靜,任進;蘇州地區(qū)I-A型花崗巖特征與成因的對比研究[J];地球科學;1997年03期

5 任紀舜;陳廷愚;劉志剛;;中國東部構(gòu)造單元劃分的幾個問題[J];地質(zhì)論評;1984年04期

6 陳榮,周金城;福建同安角閃輝長巖的礦物化學、~(40)Ar-~(39)Ar年齡及地質(zhì)意義[J];地質(zhì)論評;2001年06期

7 林清茶;程雄衛(wèi);張玉泉;汪方躍;;活動大陸邊緣花崗巖類演化——以福州復式巖體為例[J];地質(zhì)學報;2011年07期

8 黃會清;李獻華;李武顯;劉穎;;南嶺大東山花崗巖的形成時代與成因——SHRIMP鋯石U-Pb年齡、元素和Sr-Nd-Hf同位素地球化學[J];高校地質(zhì)學報;2008年03期

9 洪大衛(wèi),王式m8,韓寶福,靳滿元;堿性花崗巖的構(gòu)造環(huán)境分類及其鑒別標志[J];中國科學(B輯 化學 生命科學 地學);1995年04期

10 孫濤,周新民,陳培榮,李惠民,周紅英,王志成,沈渭洲;南嶺東段中生代強過鋁花崗巖成因及其大地構(gòu)造意義[J];中國科學(D輯:地球科學);2003年12期

，

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