本文選題：班公湖-怒江縫合帶西段 + 蛇綠巖　； 參考：《成都理工大學》2017年碩士論文

【摘要】：在野外地質(zhì)調(diào)查基礎(chǔ)上,對班公湖-怒江縫合帶西段納屋錯地區(qū)的蛇綠巖進行了詳細的野外出露特征、巖石學特征、地球化學特征、稀土元素特征及微量元素特征等進行分析測試,查明了主要巖石類型、巖石組合;分析并探討了該區(qū)的蛇綠巖成因及構(gòu)造環(huán)境,討論了班公湖-怒江縫合帶西段的形成環(huán)境。研究區(qū)內(nèi)納屋錯蛇綠巖主要零星分布于納屋錯東、生革拉北的局部地段和賽布仲久以西地段,局限于班公錯-怒江結(jié)合帶內(nèi),出露面積近10Km2,呈構(gòu)造巖(殘)塊形式產(chǎn)出于木嘎崗日巖群砂礫巖或砂板巖中,為納屋錯構(gòu)造混雜巖帶的組成成員之一。對縫合帶內(nèi)蛇綠巖巖石學及巖相學研究表明,巖石主要為蛇紋巖(全蝕變輝石橄欖巖)、綠泥石化單輝輝石巖、纖閃角閃石巖、絹云綠泥石化角閃石巖、綠簾角閃斜長巖、強蝕變玄武巖、巖墻群、硅質(zhì)巖組成�？p合帶內(nèi)超基性巖以高Cr、Ni、Co、稀土總量,低Mg值為特征,主量元素及稀土元素特征表明其與蝕變玄武巖具有同源巖漿的特點。蝕變玄武巖的主量元素顯示其具有拉斑玄武巖向堿性玄武巖過渡的特征;微量元素結(jié)果分析表明它與典型大洋中脊玄武巖明顯不同,分配形式近似平坦型,相對富集大離子親石元素Rb、Ra、Sr和高強度元素Th、Ta、Hf,但Nb虧損;在稀土元素配分模式中為輕稀土富集的向右緩傾型式,無明顯的Eu異常,但負Ce異常,與洋島堿性玄武巖的特征相似。根據(jù)蛇綠巖的地球化學特征并應用構(gòu)造環(huán)境判別圖解,確定該地區(qū)蛇綠巖形成于洋脊擴張環(huán)境,但不是典型的大洋型蛇綠巖,類似于邊緣海型蛇綠巖。
[Abstract]:On the basis of field geological survey, the characteristics of outcrop, petrology and geochemistry of ophiolite in Nawuco area of the western section of Bangong Lake-Nujiang suture zone are studied in detail. The characteristics of rare earth elements and trace elements are analyzed and tested, the main rock types and rock assemblages are identified, the genesis and tectonic environment of ophiolite in this area are analyzed and discussed, and the formation environment of the western section of Bangong Lake-Nujiang suture belt is discussed. In the study area, the Nawuco ophiolite is mainly scattered in the east of Nahuo, the part of Shengguela north and the west of Saibuzhongjiu, which is confined to the Bangongcao-Nujiang junction zone. The outcrop area is nearly 10km ~ 2, which is formed in the form of tectonic rock (remnant) in the grit or slate of Mugagangri rock group, and is one of the members of the Nawuso tectonic melange belt. The petrology and petrographic study of ophiolite in the suture zone indicate that the main rocks are ophiolite (total altered pyroxene peridotite, monopodiorite, diorite, sericite, hornblende, hornblende). Strong altered basalt, rock dike group, siliceous rock composition. The ultrabasic rocks in the suture zone are characterized by high Cr-NiCo, total rare earth elements and low mg values. The characteristics of principal elements and rare earth elements indicate that the ultrabasic rocks have the characteristics of homologous magma with altered basalt. The main elements of altered basalt show that it is characterized by the transition from tholeiite to alkaline basalt, and the trace element analysis shows that it is obviously different from typical basalt in mid-oceanic ridge, and its distribution is approximately flat. It is relatively rich in the large ion lithophile element RbPe Rau Sr and the high strength element Th TaTaHf, but NB is depleted. In the REE distribution model, there is no obvious EU anomaly, but negative ce anomaly, which is similar to the characteristics of the oceanic basalts. Based on the geochemical characteristics of ophiolite and the application of tectonic environment discriminant diagram, it is determined that ophiolite was formed in the spreading environment of the oceanic ridge, but not typical oceanic ophiolite, similar to the marginal sea ophiolite.
【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：P588.1

【參考文獻】

相關(guān)期刊論文 前7條

1 吳小雙;陶專;萬永文;胡雋;孟佳克;;班公錯—怒江縫合帶西段納屋錯蛇綠巖特征[J];金屬礦山;2014年06期

2 康志強;許繼峰;王保弟;陳建林;;拉薩地塊北部去申拉組火山巖:班公湖-怒江特提斯洋南向俯沖的產(chǎn)物?[J];巖石學報;2010年10期

3 邱瑞照,鄧晉福,周肅,李廷棟,肖慶輝,郭鐵鷹,蔡志勇,李國良,黃圭成,孟祥金;青藏高原西部蛇綠巖類型:巖石學與地球化學證據(jù)[J];地學前緣;2005年02期

4 葉培盛,吳珍漢,胡道功,江萬,楊欣德;西藏納木錯西岸蛇綠巖的地球化學特征及其形成環(huán)境[J];現(xiàn)代地質(zhì);2004年02期

5 楊日紅,李才,遲效國,王天武;西藏永珠—納木湖蛇綠巖地球化學特征及其構(gòu)造環(huán)境初探[J];現(xiàn)代地質(zhì);2003年01期

6 潘桂棠,李興振,王立全,丁俊,陳智粱;青藏高原及鄰區(qū)大地構(gòu)造單元初步劃分[J];地質(zhì)通報;2002年11期

7 潘裕生;班公湖-怒江帶中段構(gòu)造性質(zhì)探討[J];地質(zhì)科學;1984年02期

相關(guān)碩士學位論文 前1條

1 張旦;西藏納屋錯地區(qū)中酸性侵入巖的年代學、巖石化學特征研究[D];成都理工大學;2013年

，

本文編號：1970684