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DIFFERENT VARIETIES OF MIOCENE LEUCOGRANITE IN THE ARUN VALLEY—EVEREST—MAKALU AREA:FIELD RELATIONS, PETROLOGY AND ISOTOPE GEOCHEMISTRY
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作者 D.Visona 1, I.M.Villa 2, P.Pertusati 3, B.Lombardo 4 2 Universitt Bern, Isotopengeologie, Erlachstrasse 9a, CH\|3012 Bern,Switzer and 3 Dip. Scienze della Te 《地学前缘》 EI CAS CSCD 2000年第S1期100-101,共2页
Large plutons and dyke networks of Miocene leucogranite, magnificently exposed in Makalu, Nuptse and Cho Oyu, occur in the Cho—Oyu—Everest—Makalu Range at the top of the Higher Himalayan Crystalline (HHC) nappe and... Large plutons and dyke networks of Miocene leucogranite, magnificently exposed in Makalu, Nuptse and Cho Oyu, occur in the Cho—Oyu—Everest—Makalu Range at the top of the Higher Himalayan Crystalline (HHC) nappe and along the South Tibetan Detachment (STD). In the Kharta\|Dzakar Chu area, in the western limb of the Arun transverse anticline, discordant leucogranite dykes were found in the Precambrian—Cambrian (?) sediments of the Tibetan Series just above the STD (North Col Formation), throughout the HHC nappe, in the thrust sheets of the MCT zone (Main Central Thrust II sensu Arita, 1983) and in the underlying granite gneisses of the Lesser Himalayan Crystallines (LHC) which crop out in the Ama Drime —Nyonno Ri Range. While Miocene leucogranites in the HHC and in the Tibetan Series are known from end to end of the Himalaya, Miocene leucogranites in the MCT zone and in the Lesser Himalaya have not been frequently described. 展开更多
关键词 MIOCENE leucogranite MINERALOGY Nd ISOTOPE
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淡色花岗岩的岩石学和地球化学特征及其成因 被引量:27
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作者 郭素淑 李曙光 《地学前缘》 EI CAS CSCD 北大核心 2007年第6期290-298,共9页
淡色花岗岩(leucogranite)是一类高铝高硅碱的酸性侵入岩,主要地球化学特征是:SiO2≥72%,Al2O3≥14%,Na2O+K2O^8.5%,富Rb,亏损Th、Ba、Sr,稀土总量较一般花岗岩低(∑REE=(40~120)×10-6),且表现为中等分异的轻稀土弱富集型,一般具... 淡色花岗岩(leucogranite)是一类高铝高硅碱的酸性侵入岩,主要地球化学特征是:SiO2≥72%,Al2O3≥14%,Na2O+K2O^8.5%,富Rb,亏损Th、Ba、Sr,稀土总量较一般花岗岩低(∑REE=(40~120)×10-6),且表现为中等分异的轻稀土弱富集型,一般具有Eu负异常;Sr-Nd-Pb-O同位素指示其岩浆明显的陆壳来源。淡色花岗岩主要发育于陆壳(俯冲)碰撞加厚带,由逆冲折返的俯冲板片变沉积岩部分经过脱水熔融产生。淡色花岗岩可划分为三种不同的岩石类型:(1)二云母型淡色花岗岩,由变泥质岩(或变硬砂岩)在中地壳水平经黑云母(和/或白云母)脱水熔融产生;(2)电气石型淡色花岗岩,由变泥质岩在较低温度下经白云母脱水熔融产生;(3)石榴子石型淡色花岗岩,由长英质下地壳经黑云母脱水熔融产生。源区残留独居石、磷灰石等富REE矿物是淡色花岗岩亏损REE、Th等元素的原因。源岩为变泥质岩及源区残留钾长石是淡色花岗岩亏损Sr、Ba的主要原因。 展开更多
关键词 淡色花岗岩(leucogranite) 高喜马拉雅 大陆碰撞 脱水熔融
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