發(fā)布時間：2018-04-25 09:31

  本文選題：鋯石LA-ICP-MS + U-Pb年齡��； 參考：《地質(zhì)科技情報》2017年06期

【摘要】：五團巖體位于南嶺地區(qū)西段,主要巖性為黑云母二長花崗巖。利用LA-ICP-MS微區(qū)原位測試技術(shù),對五團巖體黑云母二長花崗巖進行了鋯石U-Pb定年及CL顯微結(jié)構(gòu)分析。結(jié)果表明:2件鋯石樣品的~(206)Pb/~(238)U加權(quán)平均年齡分別為(211±0.95)Ma(MSWD=0.08)和(227±3.2)Ma(MSWD=1.9),結(jié)合前人獲得的年齡數(shù)據(jù),認為巖體形成于晚三疊世中期且具有多次侵位;巖石具高硅、富鋁、高鉀特征,w(SiO_2)70.54%~72.55%,平均71.67%;w(Al_2O_3)13.62%~14.55%,平均14.03%;w(K_2O)4.18%~5.28%,平均4.85%;全堿(Na_2O+K_2O)7.09%~7.89%,平均7.51%;K_2O/Na_2O比值1.44~4.51,平均2.02;總體屬鐵質(zhì)、高鉀鈣堿性-鉀玄巖系列過鋁質(zhì)花崗巖類;Ba、Nb、Sr、P、Ti表現(xiàn)為明顯虧損,Rb、Th、U、K、La、Ce、Nd、Zr、Hf、Sm、Y、Yb、Lu等則相對富集,w(∑REE)62.07×10~(-6)~149.58×10~(-6),平均126.68×10~(-6),δEu值0.26~0.50,地球化學特征表明花崗巖為S型花崗巖,源巖主要為中、上地殼變質(zhì)雜砂巖;花崗巖微量元素構(gòu)造環(huán)境判別圖解主要顯示為后碰撞構(gòu)造環(huán)境�；趲r石成因、構(gòu)造環(huán)境判別以及區(qū)域構(gòu)造演化過程,推斷五團巖體形成于印支晚期后碰撞環(huán)境,是加厚地殼在碰撞應(yīng)力減弱、深部壓力降低等條件下部分熔融的產(chǎn)物。
[Abstract]:The Wutuan rock body is located in the west section of Nanling area, and the main lithology is biotite monzogranite. Zircon U-Pb dating and CL microstructure analysis of biotite monzogranites in Wuduan rock mass were carried out by using LA-ICP-MS microregional in-situ measurement technique. The results show that the weighted mean ages of 2 zircon samples are 211 鹵0.95MaMMSWDN0.08) and 227 鹵3.2MaMSWDU respectively. Combined with the obtained age data, it is considered that the rock mass was formed in the middle late Triassic and has multiple intrusions, and the rocks are high in silicon, rich in aluminum, and rich in aluminum. 72.55, 72.55 and 72.55, with an average of 71.67 wAl2O2o, 13.6222, 14.5555, with an average of 14.03wK2O2O4.185.285.85. the whole alkali Na2OK2O7.097.89and the average 7.51K / Na2O / Na2O / Na2O ratio 1.444.51a, an average of 2.02; the whole body belongs to iron, and the total Na2OK2O7.097.89and the average 7.51K2O/ Na2O / Na2O / Na2O ratio of 1.444.51, on average 2.02; the total is iron, In the peraluminous granitoids of the high-potassium calc-alkaline-potash series, the baccaluminous granitoids Ba-Nb-Nb-Sr-Pa-Ti show obvious depletion of RbTH (RbThU), and the source rocks are mainly medium and upper crustal metamorphic sandstone (鈭，

本文編號：1800762