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Journal of Earth Science 2020年第5期31卷 867-874页

作者： Jiangbo Wang Tong Li Yan Zhang Weihong Li State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi'an 710069China Research Institute No.203 CNNC、Xianyang 712000China

Paleozoic granites can provide important insights of crustal differentiation and collision process of the North Qinling terrane. The Dafanggou leucogranites that intruded in the Qinling Complex is a Paleozoic granite with zircon U-Pb age of 404±6.4 Ma(MSWD=0.13, n=9). The leucogranites display moderate SiO2(68.4 wt.% to 71.7 wt.%) content and high Na2O/K2O(1.07 to 2.74) and Sr/Y(42 to 65) ratios, and low A/CNK(1.04 to 1.08) and Rb/Sr(0.09 to 0.16) ratios. Combined with negative ε(Nd)(t)(-10.4) and ε(Hf)(t)(-9.35 to-0.25) values and ancient TDM2 ages(1.2 to 1.7 Ga), suggesting the leucogranite are derived from ancient amphibolitic crust in the Qinling Group. In addition, the absence of coeval mafic igneous rocks or mafic enclaves occurred in the Dafanggou pluton and the low T(Zrn)(~700 ℃) of leucogranites preclude that the leucogranites derived from high temperature dehydration melting of amphibolite. Thus, we propose that the occurrence of the Dafanggou leucogranite indicates that water-flux melting of middle-lower crust in postcollision setting may be a potential model for the genesis of granites in collisional orogenic belt.

关键词： leucogranite North Qinling Late Paleozoic crustal differentiation zircon Lu-Hf isotope

Geochronological and geochemical constraints on the Cuonadong leucogranite, eastern Himalaya

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Acta Geochimica 2018年第3期37卷 347-359页

作者： Jiajia Xie Huaning Qiu Xiujuan Bai Wanfeng Zhang Qiang Wang Xiaoping Xia State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640 China Key Laboratory of Tectonics and Petroleum Resources(China University of Geosciences Wuhan) Ministry of Education Wuhan 430074 China University of Chinese Academy of Sciences Beijing 100049China

First comprehensive investigations of the Cuonadong leucogranite exposed in North Himalayan gneiss dome of southern Tibet are presented in this *** SIMS U–Pb ages of oscillatory zircon rims scatter in a wide range from 34.1 to 16.0 Ma, and the Cuonadong leucogranite probably emplaced at 16.0 Ma. High-precision ^(40)Ar/^(39)Ar dating on a muscovite sample yields an essentially flat age spectrum with consistent plateau and isochron ages, indicating that the Cuonadong leucogranite cooled below 450 °C at 14 Ma. Based on the youngest zircon U–Pb age and muscovite^(40)Ar/^(39)Ar age, the Cuonadong leucogranite experienced rapid cooling with a rate of 119 °C/Myr from 16 to 14 Ma. The geochronological data of this undeformed leucogranite also suggest that the ductile extension of the South Tibetan Detachment System in the eastern Himalaya ceased by ca. 14 Ma. Furthermore,the initial Sr–Nd isotopic compositions and Nd model ages demonstrate that the leucogranite was derived from metapelitic source within the Greater Himalayan Crystalline Complex. The distinct Ba depletion with high Rb/Sr ratios and negative Eu anomalies make it clear that the leucogranite melts were generated by breakdown of muscovite under fluid-absent conditions.

关键词： leucogranite SIMS zircon U-Pb dating 40Ar/39Ar dating Geochemistry North Himalaya

DIFFERENT VARIETIES OF MIOCENE leucogranite IN THE ARUN VALLEY—EVEREST—MAKALU AREA:FIELD RELATIONS, PETROLOGY AND ISOTOPE GEOCHEMISTRY

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地学前缘 2000年第S1期7卷 100-101页

作者： D.Visona 1, I.M.Villa 2, P.Pertusati 3, B.Lombardo 4[WT5,5”BX](1 Dip. Mineralogiae Petrologia, corso Garibaldi 37, I\|35137 Padova,Italy 2 Universitt Bern, Isotopengeologie, Erlachstrasse 9a, CH\|3012 Bern,Switzer and 3 Dip. Scienze della Te

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.

关键词： Miocene leucogranite mineralogy Nd isotope

A Jurassic peraluminous leucogranite from Yiwul(u|¨)shan,western Liaoning,North China craton:age,origin and tectonic significance

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A Jurassic peraluminous leucogranite from Yiwul(u|¨)shan,we...

Cesium-rubidium mineralization in Himalayan leucogranites

中国科学院地质与地球物理研究所2008学术年会

作者： SIMON A.WILDE Department of Applied Geology Curtin University of TechnologyPerth WAAustralia

The Gangjia granite stock is a garnet-bearing muscovite leucogranitic body emplaced in Yiwulushan in Western Liaoning Province at the eastern segment of the Yanshan orogenic belt, North China *** SHRIMP U-Pb zircon age is 153±5 *** Gangjia granites are peraluminous with A/CNK of more than 1.14,and exhibit a tetrad effect in their REE distribution patterns,as well as non-charge-and-radius-controlled trace element *** is in contrast to the LREE-enriched patterns of the host Liishan *** geochemical characteristics, together with low Th/U ratios in zircon,suggest that the parental magmas for the Gangjia granites have experienced extensive magmatic differentiation,including interaction between residual melt and a coexisting high-temperature aqueous *** similarε(t),model ages,compatible age patterns and common volcanic arc signature in source materials between the Gangjia granites and the host L(u|¨)shan monzogranites indicate their comagmatic *** unusual peraluminous leucogranites,coupled with the voluminous adakitic granites hosting them,represent typical postorogenic magmatism developed under an intra-continental extensional tectonic *** the very end of the prolonged Jurassic magmatic evolution in Western Liaoning,extensive fractionation of most probably ferromagnesian phases and plagioclase from a calc-alkaline magma parental to the host L(u|¨)shan pluton,with overprint of the magmatic hydrothermal fluid,produced highly evolved peraluminous parental magmas for the Gangjia granites.

关键词： leucogranite geochemistry petrogenesis North China craton

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Science China Earth Sciences 2023年第12期66卷 2827-2852页

作者： Fangyang HU Xiaochi LIU Shaoxiong HE Jiamin WANG Fuyuan WU Key Laboratory of Mineral Resources Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 00029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper presents a study of a newly discovered pollucite-lepidolite-albite granite(PLAG)in the Himalayan leucogranite belt,which marks the first occurrence of pollucite,a major cesium silicate mineral,in the Himalayan orogenic belt(China).The rock appears at the northern part of the Gyirong pluton,coexisting with the tourmaline-bearing two-mica granite(TMG).Primary rare-metal minerals include lepidolite(Li),spodumene(Li),pollucite(Cs),cassiterite(Sn),and microlite(Ta).Micas,mainly lithian muscovite to lepidolite,contain 4.07 wt.%Li_2O and 0.76 wt.%Rb_2O on *** average Li_2O content of the spodumene is 7.95 wt.%.Pollucite not only has an average Cs_2O content of 34 wt.%,but also has an elevated Rb_2O content of about 0.16 wt.%.Notably,this granite attains industrial grades for rare metals,specifically with Li_2O,Rb_2O,and Cs_2O contents of 0.49–1.19 wt.%,0.12–0.24 wt.%,and 0.69–2.33 wt.%,*** results of magmatic accessory cassiterite and monazite indicated that the PLAG was formed at 19–18 Ma,slightly later than the TMG(22–20 Ma)of the Gyirong ***,these two types of granites may form within the same magmatic system considering their pulsating intrusive contact,formation ages,and whole-rock and mineral chemical ***,the abundant presence of pollucite suggests that the PLAG experienced high degrees of magmatic *** comparison to the Pusila spodumene pegmatite in the Himalaya and the Yashan topaz-lepidolite granite in Jiangxi,South China,the Gyirong PLAG exhibits different whole-rock and mineral compositions,resulting from differences in source materials and fractionation ***,the difference in fluorine(F)content may determine the degree of rare-metal element *** discovery of Gyirong PLAG highlights multiple stages and types of rare-metal mineralization in the Himalayan leucogranite belt,which is controlled by the South Tibetan Detachment *** Cs-bearing geyserite deposit exp

关键词： Himalaya Pollucite Lepidolite leucogranite Rare-metal elements

Barium isotope evidence for the role of magmatic fluids in the origin of Himalayan leucogranites

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Science Bulletin 2021年第22期66卷 2329-2336,M0004页

作者： Fang Huang Ruixia Bai Gengxin Deng Xiaochi Liu Xianhua Li CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

As an important post-collisional magmatic product in the orogenic belt, the Himalayan leucogranites are the critical host rocks for a number of rare-metal mineralization(such as Li, Be, Cs, Rb, Nb, Ta, and Sn).However, there is still a lack of good understanding on the formation and evolution of the ***, the role of the magmatic fluids in transporting and enriching the rare elements is not *** we measure Ba isotope compositions for leucogranites from the Kampa Dome of the Himalayan belt to understand the fluid activity and behavior of fluid-mobile elements during leucogranite formation. Our results show that the δ138/134 Ba of leucogranites range from -1.32‰ to +0.12‰, much lower than the literature values for S-type granites and various sedimentary materials, suggesting that the Ba isotope compositions of the leucogranites does not reflect the sedimentary source signatures. Instead, their low δ138/134 Ba is accompanied by non-charge-and-radius-controlled(CHARAC) twin-element(such as Nb/Ta) behaviors, clearly showing the involvement of magmatic fluids during magma *** studies suggest that the low δ138/134 Ba of the magmatic fluids most likely results from exsolution from a large deep magma reservoir. Such fluids not only modified Ba isotope compositions of the leucogranites, but also transported many fluid-mobile metal elements which may help form the rare metal ore deposits. Therefore, Ba isotope data provide new insights into formation and evolution of magmatic fluids and exploration of the rare-metal mineralization.

关键词： Himalaya leucogranite Barium isotopes Fluid interaction Rare-metal mineralization

Miocene Crustal Anatexis of Paleozoic Orthogneiss in the Zhada Area,Western Himalaya

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Acta Geologica Sinica(English Edition) 2022年第3期96卷 954-971页

作者： CHEN Han HU Guyue ZENG Lingsen YU Xuhui LI Yike College of Earth Science Chengdu University of TechnologyChengdu 610059China MNR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China

Granitic gneiss(orthogneiss)and Himalayan leucogranite are widely distributed in the Himalayan orogen,but whether or not the granitic gneiss made a contribution to the Himalayan leucogranite remains *** this study,we present the petrological,geochronological and geochemical results for orthogneisses and leucogranites from the Zhada area,Western *** orthogneiss is composed mainly of quartz,plagioclase,K-feldspar,biotite and muscovite,with accessory zircon and *** zircon cathodoluminescence(CL)images show that most grains contain a core with oscillatory zoning,which indicates an igneous *** high-resolution ion microprobe(SHRIMP)U-Pb dating of the zircon cores in the orthogneiss shows a weighted ^(206)Pb/^(238)U age of 515±4 Ma(early Paleozoic),with sponge-like zircon rims of 17.9±0.5 Ma(Miocene).Zhada leucogranite shows^(206)Pb/^(238)U ages ranging from 19.0±0.4 Ma to 12.4±0.2 Ma,the weighted average age being 16.2±0.4 *** leucogranites have a low Ca content(leucogranite derived from muscovite dehydration partial melting of metasediments and representative of most Himalayan *** highly variable Na_(2)O+K_(2)O(4.33 wt%-9.13 wt%),Al_(2)O_(3)(8.44 wt%-13.51 wt%),ΣREE(40.2-191.0 ppm),Rb(67.0-402 ppm)and Nb(8.23-26.4 ppm)contents,^(87)Sr/^(86)Sr(t)ratios(0.7445-0.8605)andεNd(t)values(−3.6 to−8.2)indicate that the leucogranite is derived from a heterogenetic *** nonradiogenic Nd isotope values of the studied Zhada leucogranite and orthogneiss range from−8.2 to−3.6 and from−8.7 to−4.1,***,the general mixing equation was used to perform the Sr and Nd isotope mixing *** results indicate that the heterogenetic source was the Tethyan Himalayan Sequence(THS)/Higher Himalayan Crystalline

关键词： leucogranite orthogneiss petrogenesis crustal anatexis Zhada area Himalayan orogen

Dehydration Melting and Proterozoic Granite Petrogenesis in a Collisional Orogen——A Case from the Svecofennian of Southern Finland

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Journal of Earth Science 2021年第6期32卷 1289-1299页

作者： Tom Andersen O.Tapani Rämö Department of Geosciences University of OsloN-0316OsloNorway Department of Geosciences and Geography Geology and Geophysics Research ProgramUniversity of Helsinki00014HelsinkiFinland

Dehydration melting of metasupracrustal rocks at mid-to deep-crustal levels can generate water undersaturated granitic *** this study,we evaluate the potential of~1.89–1.88 Ga metasupracrustal rocks of the Precambrian of southern Finland as source rocks for the 1.86–1.79 Ga late-orogenic leucogranites in the region,using the Rhyolite-MELTS *** close in composition to leucogranite is produced over a range of realistic pressures(5 to 8 kbar)and temperatures(800 to 850℃),at 20%–30%of partial melting,allowing separation of melt from unmelted *** solid residue is a dry,enderbitic to charnoenderbitic ganulite depleted in incompatible components,and will only yield further melt above 1000–1050℃,when rapidly increasing fractions of increasingly calcic(granodioritic to tonalitic)melts are *** solid residue after melt extraction is incapable of producing syenogranitic magmas similar to the Mid-Proterozoic,A-type rapakivi granites on further *** granitic fraction of the syenogranitic rapakivi complexes must thus have been formed by a different chain of processes,involving mantle-derived mafic melts and melts from crustal rock types not conditioned by the preceding late-orogenic Svecofennian anatexis.

关键词： leucogranite rapakivi granite anatexis restite depleted granulite Finland

Timing of Displacement along the Yardoi Detachment Fault,Southern Tibet:Insights from Zircon U-Pb and Mica 40Ar-39Ar Geochronology

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Journal of Earth Science 2019年第3期30卷 535-548页

作者： Hanwen Dong Yuanku Meng Zhiqin Xu Hui Cao Zhiyu Yi Zeliang Ma Key Laboratoiy of Deep-Earth Dynamics of Ministry of Natural Resources Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China College of Earth Science and Engineering Shandong University of Science and Technology Qingdao 266590 China School of Earth Sciences and Engineering Nanjing University Nanjing 210023 China

The Yardoi dome is located in the eastern end of the northwest-southeast extending North Himalayan domes (NHD). The dome exposes a granite pluton in the core and three lithologictectonic units separated by the upper detachment fault and the lower detachment fault. The Yardoi detachment fault (YDF), corresponding to the lower detachment fault, is a 800 m strongly deformed top-NW shear zone. LA-1CP-MS zircon U-Pb dating yielded a crystallization ages of 19.57±0.23 to 15.5±0.11 Ma for the leucogranite dyke swarm, which indicates that the ductile motion along the YDF began at ca. 20 Ma. The 40Ar/39Ar muscovite ages of 14.05±0.2 to 13.2±0.2 Ma and the 40Ar/39Ar biotite age of 13.15±0.2 Ma, suggest that the exhumation led to cooling through the 370℃ Ar closure temperature in muscovite at ~14 Ma to the 335℃ Ar closure temperature in biotite at ~13 Ma. Our new geochronological data from the Yardoi dome and other domes in the Tethyan Himalayan Sequences suggest that the ductile deformation in the region began at or before^36 Ma in a deep tectonic level, resulting in southward ductile flow at the mid-crustai tectonic level that continued from 20 to 13 Ma. Comparing the Yardoi dome to other domes in the NHD, the cooling ages show a clear diachronism and they are progressively younger from the West Himalayan to the East Himalayan.

关键词： leucogranite geochronology Yardoi dome southern Tibet Himalayan Orogen

Experimental study on dehydration melting of natural biotite-plagioclase gneiss from High Himalayas and implications for Himalayan crust anatexis

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Chinese Science Bulletin 2001年第10期46卷 867-872页

作者： YANG Xiaosong JIN Zhenmin Ernst Huenges Frank R.Schilling Bernd Wunder Faculty of Earth Sciences China University of GeosciencesWuhan 430074China GeoForschungsZentrum PotsdamD-14473Germany

Here we present the results of dehydration melting, melt morphology and fluid migration based on the dehydration melting experiments on natural bio-tite-plagioclase gneiss performed at the pressure of 1.0-1.4 GPa, and at the temperature of 770-1028℃. Experimental results demonstrate that: (i) most of melt tends to be distributed along mineral boundaries forming 'melt film' even the amount of melt is less than 5 vol%; melt connectivity is controlled not only by melt topology but also by melt fraction; (ii) dehydration melting involves a series of subprocesses including subsoiidus dehydration reaction, fluid migration, vapor-present melting and vapor-absent melting; (iii) experiments produce peraluminous granitic melt whose composition is similar to that of High Himalayan leucogranites (HHLG) and the residual phase assemblage is Pl+Qz+ Gat+Bio+Opx±Cpx+IIm/Rut±Kfs and can be comparable with granulites observed in Himalayas. The experiments provide the evidence that biotite-plagioclase gneiss is one of

关键词： gneiss dehydration melting melt topology fluid migration leucogranite granulite Himalayas.