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《東昆侖東段香日德地區(qū)察汗陶勒蓋正長(zhǎng)花崗巖LA-ICP-MS鋯石U-Pb年齡及其地質(zhì)意義.pdf》由會(huì)員上傳分享,免費(fèi)在線閱讀,更多相關(guān)內(nèi)容在行業(yè)資料-天天文庫(kù)。
1、第35卷第5期地質(zhì)通報(bào)Vo1.35.No.52016年5月GEoLoGICALBULLETINoFCHINAMav.2016東昆侖東段香日德地區(qū)察汗陶勒蓋正長(zhǎng)花崗巖LA—ICP-MS鋯石U-Pb年齡及其地質(zhì)意義鄧文兵,裴先治。,劉成軍,李佐臣L,李瑞保。,陳有斷,陳國(guó)超,楊森,陳功,桑繼鎮(zhèn),王旭斌DENGWenbing,PEIXianzhi’。,LIUChengjun’,LIZuochen,LIRuibao,CHENYouxin,CHENGuochao,YANGSen,CHENGong,SANGJizhen,WANGXubin1.長(zhǎng)安大學(xué)地球科學(xué)與資源學(xué)院,陜西西安710054
2、;2.西部礦產(chǎn)資源與地質(zhì)工程教育部重點(diǎn)實(shí)驗(yàn)室,陜西西安7100541.SchoolofEarthScienceandResource,Chang'anUniversity,Xi"an710054,Shaanxi,China;2.KeyLaboratoryofWesternMineralResourcesandGeologicalEngineeringofn如ofEducation,Xi"an710054,Shaanxi,China摘要:東昆侖造山帶東段察汗陶勒蓋地區(qū)出露一套肉紅色正長(zhǎng)花崗巖,用LA—ICP—MS技術(shù)測(cè)得的鋯石u—Pb年齡為239.9±0.7Ma,表明該巖體形成于
3、中三疊世。地球化學(xué)特征表明,察汗陶勒蓋正長(zhǎng)花崗巖屬于過鋁質(zhì)高鉀鈣堿性系列,巖石具有高SiOz、A10,、K20和低TiOz、MnO、CaO的特征,A/CNK為1.05-1.13(平均值為1.10),K2O/NaO值介于0.95-1.16之間,里特曼指數(shù)盯為1.56~2.24,CIPW標(biāo)準(zhǔn)礦物計(jì)算的剛玉質(zhì)量分?jǐn)?shù)大于1%,礦物組合中出現(xiàn)白云母等富鋁礦物,顯示s型花崗巖特征。稀土元素總量為61.47x10一-145.23x10一,球粒隕石標(biāo)準(zhǔn)化配分曲線顯示,輕稀土元素富集((La/Yb)=15.83~27.11),且有明顯的負(fù)Eu異常(8Eu=0.26~0.49)。原始地幔標(biāo)準(zhǔn)化蛛網(wǎng)
4、圖顯示,巖石富集Rb、La、Th,虧損Ba、Ta、sr、P、Ti等元素。微量和稀土元素特征顯示出明顯的殼源特征,其源巖可能為以上地殼雜砂質(zhì)巖為主的沉積巖。結(jié)合區(qū)域資料認(rèn)為,察汗陶勒蓋正長(zhǎng)花崗巖體具有過渡型花崗巖的特征,形成于俯沖向同碰撞轉(zhuǎn)化階段,是東昆侖南緣青山一阿尼瑪卿洋殼俯沖晚期的產(chǎn)物。關(guān)鍵詞:東昆侖東段;正長(zhǎng)花崗巖;中三疊世;LA—ICP—MS鋯石u—Pb測(cè)年;俯沖造山中圖分類號(hào):P534.51;P597~.3文獻(xiàn)標(biāo)志碼:A文章編號(hào):1671—2552(2016)05—0687—13DengWB,PeiXZ,LiuCJ,LiZC,LiRB,ChenYX,ChenGC,Ya
5、ngS,ChenG,SangJZ,WangXB.LA-ICP-MSzir-conU—PbdatingoftheChahantaolegaisyenogranitesinXiangrideareaofEastKunlunanditsgeologicalsignificance.Geo·logicalBulletinofChina,2016,35(5):687-699Abstract:AsuiteofsyenogranitesisexposedintheChahantaolegaiareaalongtheeasternsectionofEastKunlunOrogenicBelt.
6、LA—ICP—MSzirconU—Pbweightedaverageagesis239.9±O.7Ma.suggestingtheformationofsyenogranitesinMiddleTriassic.Accordingtothegeochemicalcharacteristics,itissuggestedthatChahantaolegaisyenogranitesbelongtoperaluminoushigh—potassiccalc—alkalineseries.TheyarecharacterizedbyhighSiO2,Al2O3,K2OandlowTi
7、O2andNa20values.A/CNK=1.05-1.13faverageA/CNK=1.10),K2O/Na2Oratiosareabout0.95~1.16,andP.ittmannindex叮=1.56~2.24;thecontentofcorundumexceeds1%.a(chǎn)sshownbyCIPWstandardmineralcalculation.Theexistenceofrock~formingmineralssuchasmuscovitesuggeststhatthesy