【摘要】：NE-SW向政和-大埔斷裂帶是華夏板塊內(nèi)部一條重要的斷裂帶,該帶內(nèi)出露大量基性-超基性巖,前人對于該帶內(nèi)基性-超基性巖的認識一直以來存在爭議。本論文主要針對該斷裂帶政和-建甌段基性-超基性巖開展鋯石U-Pb年代學及地球化學分析,意在厘清基性-超基性巖成因及構(gòu)造屬性,并以此探討華夏板塊新元古代—早古生代構(gòu)造演化。通過以上研究,本文取得以下主要認識:鋯石U-Pb定年顯示,政和-大埔斷裂帶內(nèi)基性巖大多形成于新元古代,其中水吉鎮(zhèn)雙峰式火山巖角閃斜長片巖原巖形成年齡分別為812±7 Ma,政和斜長角閃片巖原巖形成時代725±22 Ma。地球化學特征表明迪口鎮(zhèn)角閃片巖原巖巖漿來源于富集型地幔,政和斜長角閃巖巖漿來源于相對虧損的地幔,構(gòu)造判別圖解上前者為板內(nèi)玄武巖,后者具有N-MORB特征。電子探針數(shù)據(jù)表明洋后角閃石巖主要為淺閃石,Re-Os同位素和Sr-Nd同位素特征顯示洋后角閃石巖原巖為巖漿成因,巖漿來源于富集型地幔,而馬面山蛇紋巖和北歷蛇紋石化橄欖巖為大陸巖石圈殘余地幔橄欖巖。綜和上述特征政和—大埔斷裂帶內(nèi)基性巖形成于新元古代拉張構(gòu)造環(huán)境,而超鎂鐵質(zhì)巖石有的為巖漿成因,有的為殘余的地幔橄欖巖,但其是否為蛇綠巖套還需做進一步研究。沿政和-大埔斷裂帶內(nèi)也出露一些中生代的基性巖。鋯石U-Pb定年顯示東游鎮(zhèn)斜長角閃片巖原巖形成年齡為221±1 Ma。Sr-Nd同位素表明東游鎮(zhèn)斜長角閃片巖巖漿來源于富集型地幔,構(gòu)造判別圖解上巖石屬于板內(nèi)拉斑玄武巖。
[Abstract]:The NE-SW Xiangzheng-Tai Po fault zone is an important fault zone in the Huaxia plate, in which a large number of basic-ultrabasic rocks are exposed. In this paper, zircon U-Pb geochronology and geochemistry analysis are carried out for the basic-ultrabasic rocks of Zhenghe and Jianou member of the fault zone, in order to clarify the genesis and tectonic attributes of basic-ultrabasic rocks. The tectonic evolution of Neoproterozoic-early Paleozoic in the Huaxia plate is discussed. Based on the above study, the main conclusions are as follows: the zircon U-Pb dating shows that most of the basic rocks in the Zhenghe-Tai Po fault zone were formed in the Neoproterozoic. The age of formation of the amphibolite schist in Shuiji town is 812 鹵7 Ma, and 725 鹵22 Ma., respectively. The geochemical characteristics indicate that the magma of Dikouzhen hornblende schist originates from the enriched mantle, the Zhenghe and plagioclase amphibolite magma from the relatively depleted mantle. The former belongs to intraplate basalt and the latter is characterized by N-MORB. The electron microprobe data show that the post-oceanic hornblende is mainly composed of shallow-amphibole Re-Os isotopic and Sr-Nd isotopic features, indicating that the post-oceanic hornblende originates from magma, and the magma originates from the enriched mantle. The Mamanshan ophiolite and the northern serpentine peridotite are residual mantle peridotite in the continental lithosphere. The basic rocks in the Zhenghe-Tai Po fault zone were formed in the Neoproterozoic extensional tectonic environment, while the ultramafic rocks were either magmatic or residual mantle peridotite, but whether they are ophiolite suites should be further studied. Some Mesozoic basic rocks were also exposed along the Zhenghe-Tai Po fault zone. The zircon U-Pb dating shows that the age of formation of the amphibole schist is 221 鹵1 Ma.Sr-Nd isotope, indicating that the magma of Dongyou Zhen clinopodiorite schist originated from the enriched mantle, and the tectonic discrimination diagram shows that the rocks belong to intraplate tholeiite basalt.
【學位授予單位】：合肥工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：P588.12;P542

【參考文獻】

相關(guān)期刊論文 前10條

1 楊紅;劉平華;孟恩;王舫;肖玲玲;劉超輝;;揚子地塊西南緣大紅山群變質(zhì)基性巖的地球化學研究及構(gòu)造意義[J];巖石學報;2014年10期

2 汪建國;余盛強;趙旭東;吳鳴;顧明光;胡艷華;;武夷地塊中古元古代鎂鐵質(zhì)-超鎂鐵質(zhì)巖石的發(fā)現(xiàn)——剖面介紹及巖石學、巖相學、年代學特征[J];巖石礦物學雜志;2014年04期

3 黃瑞芳;孫衛(wèi)東;丁興;王玉榮;;基性和超基性巖蛇紋石化的機理及成礦潛力[J];巖石學報;2013年12期

4 張國偉;郭安林;王岳軍;李三忠;董云鵬;劉少峰;何登發(fā);程順有;魯如魁;姚安平;;中國華南大陸構(gòu)造與問題[J];中國科學:地球科學;2013年10期

5 舒良樹;;華南構(gòu)造演化的基本特征[J];地質(zhì)通報;2012年07期

6 徐先兵;張岳橋;舒良樹;賈東;王瑞瑞;許懷智;;武夷山地區(qū)前寒武紀地層沉積時代研究[J];地層學雜志;2010年03期

7 ;Reappraisement and refinement of zircon U-Pb isotope and trace element analyses by LA-ICP-MS[J];Chinese Science Bulletin;2010年15期

8 劉銳;周漢文;張利;鐘增球;曾雯;向華;靳松;呂新前;李春忠;;華夏地塊古元古代陸殼再造:鋯石微量元素與U-Pb和Lu-Hf同位素證據(jù)[J];科學通報;2009年07期

9 靳松;張利;鐘增球;周漢文;向華;曾雯;劉銳;呂新前;李春忠;;浙閩地區(qū)華夏地塊新元古代變沉積巖地球化學特征及其地質(zhì)意義[J];地球科學(中國地質(zhì)大學學報);2008年06期

10 舒良樹;于津海;賈東;王博;沈渭洲;張岳橋;;華南東段早古生代造山帶研究[J];地質(zhì)通報;2008年10期

，

本文編號：2223130