發(fā)布時(shí)間：2018-07-24 07:46

【摘要】：滇西昌寧地區(qū)的“西盟巖群”東與石炭紀(jì)牛井山蛇綠混雜巖(CNop)斷層相接,西被燕山期花崗巖侵入接觸。前人對(duì)西盟巖群的變質(zhì)作用、變形作用以及它們之間的關(guān)系研究較少,本文在野外地質(zhì)調(diào)查的基礎(chǔ)上,結(jié)合室內(nèi)薄片鑒定,準(zhǔn)確研究西盟巖群的變質(zhì)巖巖石類(lèi)型及礦物共生組合類(lèi)型;通過(guò)野外產(chǎn)狀和巖石地球化學(xué)(全巖、稀土及微量元素)的分析測(cè)試工作,對(duì)西盟巖群進(jìn)行原巖恢復(fù)并確定其原巖性質(zhì);通過(guò)礦物對(duì)的電子探針?lè)治?確定變質(zhì)作用溫壓條件;運(yùn)用鋯石U-Pb年代學(xué)測(cè)試分析,準(zhǔn)確限定變質(zhì)變形作用期次。研究區(qū)西盟巖群共劃分為三個(gè)巖性段:a段以(石榴)長(zhǎng)英質(zhì)糜棱巖、變粒巖、云母(石英)片巖、黑云斜長(zhǎng)片麻巖為主,夾少量大理巖、角閃黑云片巖等;b段以淺色變質(zhì)巖為主,主要包括長(zhǎng)英質(zhì)糜棱巖、黑云斜長(zhǎng)片麻巖、淺粒巖、石榴二云斜長(zhǎng)片巖等;c段以黑云斜長(zhǎng)片麻巖與長(zhǎng)英質(zhì)片麻巖互層為主,夾少量黑云片巖和花崗質(zhì)片麻巖。野外地質(zhì)特征結(jié)合地球化學(xué)特征表明:黑云片巖類(lèi)和石英片巖類(lèi)的原巖總體應(yīng)為副變質(zhì)巖,它們可能是由粉砂質(zhì)粘土巖或泥巖變質(zhì)而成;角閃黑云片巖的原巖可能是中基性火山巖;片麻巖類(lèi)的原巖多數(shù)為長(zhǎng)石砂巖,少數(shù)為中酸性巖漿巖;長(zhǎng)英質(zhì)糜棱巖類(lèi)可能為中酸性的巖漿巖變質(zhì)后再經(jīng)韌性剪切變形改造而成。西盟巖群中兩件鋯石U-Pb年代學(xué)樣品表明,原西盟巖群應(yīng)予解體為燕山期花崗巖和中深變質(zhì)巖系。變質(zhì)巖系僅包括片巖類(lèi)、片麻巖類(lèi)、變粒巖類(lèi)、大理巖類(lèi)、和部分長(zhǎng)英質(zhì)糜棱巖類(lèi)。西盟巖群共有三期變質(zhì)作用:主期變質(zhì)作用(M1)為角閃巖相的區(qū)域中溫中壓變質(zhì)作用,其溫壓條件為:540±10°C,0.4±0.03GPa,變質(zhì)時(shí)間為晉寧期;第二期變質(zhì)作用(M2)為同變形變質(zhì)作用,是綠片巖相的區(qū)域動(dòng)力變質(zhì)作用,其變質(zhì)時(shí)間為20Ma—14Ma間的喜山期;第三期變質(zhì)作用(M3)為綠片巖相的退變質(zhì)作用,其時(shí)間為14Ma以后。西盟巖群共有三期變形作用:第一期變形作用(D1)為主期變質(zhì)作用(M1)的同變質(zhì)的變形作用,形成了區(qū)域性的片理和片麻理;第二期變形作用(D2)是主期變質(zhì)作用(M1)后片理、片麻理發(fā)生扭折彎曲的變形作用;第三期變形作用(D3)為近南北向的左旋走滑剪切變形作用。
[Abstract]:The "Ximeng rock group" in Changning area of western Yunnan is connected with the (CNop) fault of Carboniferous Niujingshan ophiolite melange in the east and is intruded by Yanshanian granite in the west. There are few studies on metamorphism, deformation and their relationship between the Ximeng rock group. Based on the field geological survey, this paper combined with laboratory sheet identification, The types of metamorphic rocks and mineral symbiotic assemblages of Ximeng rock group are studied accurately, and the field occurrence and rock geochemistry (whole rock, rare earth elements and trace elements) are analyzed and tested. The original rocks of Ximeng rock group are restored and the original rock properties are determined; the temperature and pressure conditions of metamorphism are determined by electron probe analysis of mineral pairs; and the period of metamorphic deformation is accurately defined by zircon U-Pb chronological analysis. The Ximeng rock group in the study area is divided into three lithologic members: (pomegranate) felsic mylonite, granulite, mica (quartz) schist, black cloud plagioclase gneiss, and a small amount of marble. The amphibolite schist is mainly composed of light-colored metamorphic rocks, including felsic mylonite, black-cloud plagioclase gneiss, shallow-grained rock, pomegranate eryun plagioclase schist and so on. A small amount of black cloud schist and granitic gneiss. The field geological features combined with geochemical characteristics indicate that the source rocks of the black cloud schist and quartz schist should be metamorphic rocks, which may be metamorphic from silty clay rocks or mudstones. The primary rocks of hornblende schist may be intermediate basic volcanic rocks, most of gneiss are feldspar sandstone, a few are intermediate-acid magmatic rocks, and felsic mylonite may be formed by ductile shear deformation after metamorphism of intermediate-acid magmatic rocks. Two zircon U-Pb geochronological samples from the Ximuiyan Group indicate that the Proto-XIMU rock group should be disintegrated into Yanshanian granite and medium-deep metamorphic rock series. Metamorphic rocks include only schist, gneiss, granulite, marble and some felsic mylonites. There are three metamorphic stages in Ximeng rock group: the main metamorphism (M1) is a regional metamorphism of amphibolite facies, and the temperature and pressure conditions are as follows: (1) the metamorphism time is Jinning period, and the second stage metamorphism (M2) is syndesic metamorphism, and the temperature and pressure conditions are: (1) 540 鹵10 擄C _ (10) 擄C _ (10) 擄C _ (0) 鹵0.03 GPa. It is the regional dynamic metamorphism of the greenschist facies, whose metamorphic time is the Himalayan period between 20Ma-14Ma and the retrograde metamorphism of the greenschist facies in the third metamorphism (M3) after 14Ma. The Ximeng rock group has three stages of deformation: the first stage deformation (D1), the main metamorphism (M1), the formation of regional lithology and schism, and the second stage deformation (D2) is the main stage metamorphism (M1), and the second stage deformation (D2) is the main stage metamorphism (M1), and the second stage deformation (D2) is the main stage metamorphism (M1). The third stage deformation (D 3) is a near S N direction left lateral strike-slip shear deformation.
【學(xué)位授予單位】：成都理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：P588.3

【參考文獻(xiàn)】

相關(guān)期刊論文 前6條

1 胡斌,戴塔根,胡瑞忠,郭群;滇西地區(qū)殼體大地構(gòu)造單元的劃分及其演化與運(yùn)動(dòng)特征[J];大地構(gòu)造與成礦學(xué);2005年04期

2 張海祥,張伯友;贛北星子群變質(zhì)巖的原巖恢復(fù)及其形成構(gòu)造環(huán)境判別[J];中國(guó)地質(zhì);2003年03期

3 從柏林,吳根耀,張旗,張儒媛,翟明國(guó),趙大升,張?chǎng)┤A;中國(guó)滇西古特提斯構(gòu)造帶巖石大地構(gòu)造演化[J];中國(guó)科學(xué)(B輯 化學(xué) 生命科學(xué) 地學(xué));1993年11期

4 吳元保,鄭永飛;鋯石成因礦物學(xué)研究及其對(duì)U-Pb年齡解釋的制約[J];科學(xué)通報(bào);2004年16期

5 段建中,譚筱虹;滇西三江地區(qū)新生代主要走滑斷裂性質(zhì)及特征[J];云南地質(zhì);2000年01期

6 唐淵;尹福光;王立全;王冬兵;廖世勇;孫志明;孫潔;;滇西崇山剪切帶南段左行走滑作用的構(gòu)造特征及時(shí)代約束[J];巖石學(xué)報(bào);2013年04期

，

本文編號(hào)：2140700