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Science China Earth Sciences 2007年第1期50卷 1-16页

作者： liN GuangChun li XianHua li wuxian Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Graduate University of the Chinese Academy of Sciences Beijing 100039China

Neoproterozoic magmatic rocks are widespread in the western margin of the Yangtze block, and their origin and genesis have significant implications for understanding the evolution of the Rodinia super- continent. However, there are currently two opposing interpretations for their petrogenesis and tectonic setting: mantle plume-related and island arc origin. To further verify these two competing models, SHRIMP U-Pb zircon age determinations and geochemical and Nd-Hf isotopic analyses are conducted on the mafic dykes in the Kangdian Rift, western Sichuan. U-Pb dating suggests that these mafic dykes were emplaced at 780―760 Ma, spatially and temporally coeval with the Kangding granitoid complex. The parental magmas of these dykes were derived from a depleted asthenosphere mantle source likely triggered by an anomalously-hot mantle plume. Despite some arc-geochemical features caused by variable degrees of contamination of young island arc crust during magma ascending and emplace- ment, they show general geochemical and Nd-Hf isotopic features similar to those of the intraplate basalts. Our results support the reconstruction model of Rodinia in which the South China block was located between Australia and Laurentia.

关键词： Neoproterozoic mafic dykes Kangdian Rift South China Rodinia

On the genetic classification and tectonic implications of the Early Yanshanian granitoids in the Nanling Range, South China

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Chinese Science Bulletin 2007年第14期52卷 1873-1885页

作者： li XianHua li wuxian li Zheng-Xiang Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China State Key Laboratory of lithospheric Evolution Institute of Geology and Geophysics Chinese Acadamy of Sciences Beijing 100029 China Institute of Geoscience Research Department of Applied Geology Curtin University of Technology GPO Box U 1987 Perth WA 6845 Australia

Early Yanshanian (Jurassic) granitoids are widespread in the Nanling Range of South China, and are associated with numerous non-ferrous and rare metal mineral deposits. These granitoids consist mainly of slightly peraluminous biotite monzogranites and K-feldspar granites that are closely associated in time and space with subordinate amphibole-bearing granites and muscoviteand garnet-bearing granites. In most previous studies, the biotite-bearing granites were classified as crustal transformation-type (corresponding to the S-type) granites which were interpreted to be derived from the regional Paleoproterozoic meta-sedimentary rocks. In this paper, we re-analyze the geochemical characteristics of a number of representative Early Yanshanian Nanling granitoids. There exists a clear negative correlation between SiO2 and P2O5 for the studied granitoids. The Early Yanshanian Nanling granitoid suites (including amphibole-bearing granodiorites→biotite monzogranites→K-feldspar granites→two-mica (muscovite) granites) are metaluminous to slightly peraluminous I-type or fractionated I-type granites. They were derived predominantly from Proterozoic igneous protoliths. The juvenile crust and/or newly mantle-derived materials might also have been involved in some of these granites. In addition, the Iand fractionated I-type granites are closely associated in time and space with minor amount of A-type felsic and mafic volcanic and intrusive rocks as well as alkaline rocks. All these rocks constitute a typical assemblage of anorogenic, intraplate magmatism, suggesting a dominant lithospheric extensional regime for the Nanling Range and neighboring region during the Early Yanshanian period.

关键词：遗传分类燕山期地质学人造花岗岩面中国

Typomorphism of the {211}-type zircon

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Chinese Science Bulletin 2002年第2期47卷 154-158页

作者： WANG Xiang li wuxian Department of Earth Sciences and State Key Laboratory for Mineral Deposit Research Nanjing UniversityNanjing 210093China

A natural{211}-type zircon has been first dis-covered in the Pingtan gabbro in the Fujian Province,which is a new type of morphology reported in magmatic *** of morphology and trace-element chemistry shows two distinct growth stages,Stage 1 and Stage ***{211}-type zircon is the earliest crystallized phase of Stage 1 *** low Hf contents and extreme depletion in U,Th and Y indicate that Stage 1 zircon was approximately in equilibration with melt during the crystallization,so that they are regarded as crystallized phase in deeper magmatic *** Zr-saturated gabbroic magma is demonstrated to be derived from mantle magmas by *** magma differentiation and zircon crystallization at the lower crust level indicate the existence of underplating of mantle magma beneath this area,which results in strong magmatic activities in the late Mesozoic.

关键词： zircon {211} faces trace elements equilibrium crystallization.

The thermal history of the miarolitic granite at Xincun, Fujian Province, China

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Chinese Science Bulletin 2000年第21期45卷 1991-1995页

作者： SHEN Weizhou liNG Hongfei li Huimin li wuxian WANG Dezi State Key Laboratory for Mineral Deposits Research Department of Earth SciencesNanjing UniversityNanjing 210093China Tianjin Institute of Geology and Deposits the Ministry of Land and ResourcesTianjin 300170China Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640China

The thermal history of the late Mesozoic miarolitic granite has been studied based on zircon U-Pb dating, whole rock Rb-Sr dating and K-Ar dating of muscovite, biotite and K-feldspar from the same rock sample. From the beginning of zircon crystallization to the closure of K-Ar system of biotite, the granite body had a slow cooling rate (11.0℃/Ma) and an ascending rate (0.07 mm/a). From the end of this stage to the closure of K-Ar system of K-feldspar, the granite body increased its cooling rate (45℃/Ma) and ascending rate (0.36 mm/a). The thermal history of the Xincun granite with a slow cooling rate at the early stage and a fast cooling rate at the late stage may have been related to the fact that the Fujian coastal area had very high geothermal gradient in the late Mesozoic and evident decrease in geothermal gradient in the early Cenozoic.

关键词： closure temperature thermal history paleothermal gradient Xincun miarolitic granite.

Petrogenesis of early Yanshanian highly evolved granites in the Longyuanba area,southern Jiangxi Province:Evidence from zircon U-Pb dating,Hf-O isotope and whole-rock geochemistry

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Science China Earth Sciences 2013年第5期56卷 922-939页

作者： TAO JiHua li wuxian li XianHua CEN Tao State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of Sciences Graduate University of Chinese Academy of Sciences State Key Laboratory of lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences

Early Yanshanian(Jurassic) granitoids are widespread in the Nanling Range,South *** large granitic batholiths commonly crop out in the center of the Nanling Range(corresponding geographically to the central and northern parts of Guangdong Province),many small stocks occur in the southern part of Jiangxi *** of the small stocks are associated closely with economically significant rare-metal deposits(W,Sn,Nb,Ta).Here we report the results for biotite granites and two-mica granites from three Yanshanian stocks of the Longyuanba ***-ICPMS U-Pb dating of zircon yields an age of 156.1±2.1 Ma for Xiaomubei biotite granite,and U-Pb zircon dating using SIMS yields an age of 156.7±1.2 Ma for Longyuanba-Chengjiang biotite granite and 156.4±1.3 Ma for Jiangtoudong two-mica *** granites are silica-rich(SiO 2 =70%-79%),potassic(K 2 O/Na 2 O>1.9),and peraluminous(ASI=1.05-1.33).Associated samples are invariably enriched in Rb,Th,Pb and LREE,yet depleted in Ba,Nb,Sr,P and Ti,and their REE pattern shows a large fractionation between LREE and HREE((La/Yb) N =10.7-13.5) and a pronounced Eu negative anomaly(δEu=0.28-0.41).Two-mica granite samples are also silica-rich(SiO 2 =75%-79%),potassic(K 2 O/Na 2 O>1.2),and peraluminous(ASI=1.09-1.17).However,in contrast to the biotite granites,they are more enriched in Rb,Th,Pb and extremely depleted in Ba,Nb,Sr,P and Ti,and exhibit nearly flat((La/Yb) N =0.75-1.08) chondrite-normalized REE patterns characterized by strong Eu depletion(δEu=0.02-0.04) and clear tetrad effect(TE 1.3 =1.10-1.14).Biotite granites and two-mica granties have comparable Nd isotopic signatures,and their εNd(t) are concentrated in the 13.0 to 9.6 and 11.5 to 7.7 *** zircon Hf-O isotopes of both also show similarity(biotite granites:εHf(t)= 10.8-7.9,δ 18 O=7.98‰-8.89‰ and εHf(t)= 13.8 to 9.1,δ 18 O=8.31‰-10.08‰;two-mica granites:εHf(t)= 11.3 to 8.0,δ 18 O=7.91‰-9.77‰).The results show that both biotite and two-mica gra

关键词： highly evolved tetrad effect granite early Yanshanian southern Jiangxi Province

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Mineralogical feature and geological significance of muscovites from the Longyuanba Indosinian and Yanshannian two-mica granites in the eastern Nanling Range

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Science China Earth Sciences 2014年第10期57卷 1150-1157页

作者： TAO JiHua li wuxian CAI YuanFeng CEN Tao State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory for Mineral Deposits Research School of Earth Sciences and Engineering Nanjing University

Emplacement P-T condition estimations using granites are important for understanding metamorphic and erosional processes of orogenic *** are widespread in South China and a majority of them are ***,over 91%of the Indosinian granites exposed in the region are peraluminous in *** is extremely hard to determine the pressure of intrusion of these peraluminous granites due to the absence of amphibole,a good mineral barometer commonly identified in metaluminous *** is a common mineral in peraluminous granites,certain kind of it could be used as a mineral barometer to constrain the emplacement pressure of peraluminous *** this paper,results of petrographic and geochemical studies of muscovites from the Indosinian and early Yanshanian two-mica granites at the Longyuanba in the eastern Nanling Range are *** on petrographic studies,the primary muscovite can be discriminated from the secondary *** from the Indosinian two-mica granites are enriched in Ti,Al,Mg,and Na,and depleted in Fe and ***,these muscovites were considered as primary,whereas those from the Yanshanian two-mica granites fall into the area of secondary muscovite on discrimination *** estimations show that pressures calculated for primary muscovites are accurate,but those calculated for secondary muscovites are *** average pressure of emplacement of the Longyuanba Indosinian two-mica granites is 5.9 kbar,corresponding to^19 km in depth,suggesting that the Indosinian granitic magmas were probably generated by partial melting of a thickened crust root in a compressional tectonic setting.

关键词： emplacement depth muscovite peraluminous granites Longyuanba complex Nanling Range

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The Nd-Sr isotope study of Mesozoic granitoids in Jiangxi Province

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Chinese Science Bulletin 1999年第15期44卷 1427-1431页

作者： Weizhou Shen Hongfei ling wuxian li Dezi Wang Xuan Huang Jun Pan Nanjing Univ Dept Earth Sci Nanjing 210093 Peoples R China Chinese Acad Sci Inst Geol Beijing 100029 Peoples R China

Nd-Sr isotopic compositions of 12 Mesozoic granitoids from Jiangxi Province have been reported. They show loe-εND（-13.8—- 8.3）, high-lsr（0.71069—0.73981） and old tDM （2087—1635 Ma）. Comparison between the Sm-Nd isotopic compositions of the granitoids and those of the basement metamorphic rocks suggests that these granitoids were mainly derived from the metasedimentary rocks. There is an east-west trend Mesozoic granitoid zone with lowtDM from S. Jiangxi to S. Fujian. The origin of these granites was preliminarily discussed.

关键词： Nd-Sr isotopic compositions material source low-tDM zone Mesozoic granitoids Jiangxi Province.

Three Stages of Zircon Growth in Magmatic Rocks from the Pingtan Complex,Eastern China

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Acta Geologica Sinica(English Edition) 2007年第1期81卷 68-80页

作者： WANG Xiang W. L. GRIFFIN S. Y. O＇REILLY li wuxian State Key Laboratory for Mineral Deposit Research Department of Earth Sciences Nanjing University Nanjing Jiangsu 210093 China GEMOC ARC National Key Center Department of Earth and Planetary Sciences Macquarie University NSW 2109 Australia CSIRO Exploration and Mining North Ryde NSW 2113 Australia

Morphological and chemical studies on zircon grains from gabbro and granite of the Pingtan magmatic complex, Fujian Province, eastern China, show that there are three stages of zircon growth. The early stage of zircon growth is characterized by colorlessness, high transparence and birefringence, low and dispersive Ipr and Ipy, weak and homogeneous BSE brightness, lower Hf content and depletion of U, Th and Y; the middle stage is characterized by abruptly increasing lpy, progressively strong and sectoral-zoning BSE brightness, higher Hf content and enrichment of U, Th and Y with Th/U 〉 1; the late stage of growth is characterized by brownish color, poor transparence, low birefringence, highest Ipr and Ipy, middle and oscillatorily-zoning BSE brightness, highest contents of Hf, U and Y with Th/U 〈 1. The stages are considered to be formed in a deep magma chamber, ascent passage and emplacement site, respectively. Due to the more or less long residual time of the magma chamber, the difference in age between the early and late stages of zircon might be great enough to be distinguished, which can be attributed to tectonic constraint for the magnlatism.

关键词： zircon three stages of crystal growth typology trace element magmatic rock

Electromagnetic Abnormity Recorded by Borehole TOA Installment during the Mojiang M_S5. 9 Earthquake on September 8,2018

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Earthquake Research in China 2019年第4期33卷 648-660页

作者： li Mei li wuxian ZHAO Huaxing ZHANG li ZHANG Ping ZHANG Xuhui YU Chen China Earthquake Networks Center Beijing 100045China Earthquake Agency of Dali Bai Prefecture.No.10 Fuwen Road Dali 671000YunnanChina Yunnan Earthquake Agency No.146 Beichen RoadPanlong DistrictKunming 650011China

As an achievement of the cooperation with Japan,TOA electromagnetic observation station was established with an 800 m borehole antenna and put into service in 1992 in Dali,Yunnan province,*** wuxian et al.(2003)summarized main anomalous variation characters by analyzing 23 strong earthquakes with magnitudes more than 5.0 recorded in the first ten *** work mainly presents the electromagnetic changes prior to the last Mojiang MS5.9 earthquake on September 8,*** of all,the initial weak signals appeared in two ULF channels out of three observing channels(CH10.01-0.10 Hz,CH20.1-1.0 Hz and CH31-9 kHz)on May 30,2018 at Dali TOA electromagnetic *** information recorded was characterized by wave-like changes with magnitudes of ACH1≤0.26 mV in CH1 and pulse-like impulses of ACH2≤0.6 mV in CH2,***,abnormal information gradually enhanced either in magnitudes or in occurrence ***-like signals were full of lattices of recording paper for CH2 during June24-25 and slopped over the recording paper during June 28-29,with the magnitudes being greater than or equal to 10 *** the same time,the clear wave-like signals also appeared in CH1 with a maximum magnitude of^0.6 mV on June 28 and reached its *** then on,the information started to decrease from the end of July and only weak signals occasionally occurred till the end of August 2018,when obvious anomaly was recorded again in two ULF channels with maximum magnitudes of ACH1~0.2 mV and ACH2~0.3 mV ***,these signals did not appear continuously but group by group and accumulated intensively only in ULF band instead of VLF band during the total period.10 days later,the Mojiang MS5.9 earthquake occurred on September 8,2018,300 km away from Dali TOA station,and a coseismic response was also recorded at this ***,these ULF electromagnetic abnormities could be probably attributed to the Mojiang event.

关键词： Mojiang M_S5.9 earthquake Borehole electromagnetic abnormity Coseismic response

Qinghu zircon:A working reference for microbeam analysis of U-Pb age and Hf and O isotopes

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Chinese Science Bulletin 2013年第20期58卷 4647-4654页

作者： li XianHua TANG GuoQiang GONG Bing YANG YueHeng HOU KeJun HU ZhaoChu li Qiuli liU Yu li wuxian State Key Laboratory of lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space Sciences University of Science and Technology of China Institute of Mineral Resources Chinese Academy of Geological Sciences State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences

Zircon is the most useful mineral for studies in U-Pb geochronology and Hf and O isotope *** effect is a major problem of the microbeam techniques such as SIMS and LA-(MC)-***,external standardization using well-characterized natural zircon standards is fundamental for accurate microbeam *** the isotopic geochronology and geochemistry laboratories equipped with microbeam analytical facilities have been increasingly established in China during the past decade,applications of the isotopic microanalysis are still limited due to shortage of available *** report here the Qinghu zircon as a potential new working reference for microbeam analysis of zircon U-Pb age and O-Hf *** zircon was separated from the Qinghu quartz monzonite from the western Nanling Range,Southeast *** is fairly homogeneous in U-Pb age and Hf and O isotopes in terms of large amounts of mircobeam measurements by LA-MC-ICPMS and SIMS at the scales of 20–60 *** measurements yield consistent206Pb/238U age within analytical uncertainties with that obtained by *** determinations of O isotopes by IRMS and Hf isotopes by solution MC-ICPMS are in good agreement with the statistical mean of microbeam *** recommend U-Pb age of=159.5±0.2 Ma(2SE),18O=5.4‰±0.2‰(2SD)and176Hf/177Hf=0.283002±0.000004(2SD)as the best reference values for the Qinghu zircon.

关键词：锆石U-Pb年龄 Hf同位素微束分析天然锆石 O同位素 MC-ICPMS U-Pb年代学中国东南部

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