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U-Pb zircon ages for the Luzhenguan Complex in northern part of the eastern Dabie orogen

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Science China Earth Sciences 2005年第9期48卷 1357-1367页

作者： Wolfgang Siebe institut für geowissenschaften Universit?t Tübingen Tübingen 72074 Germany

The study presents U-Pb zircon ages for granitic gneiss and amphibolite from the Luzhenguan Complex (LZC) in northern part of the eastern Dabie Orogen and their geological significance. Two granitic gneisses and one amphibolite give protolith zircon U-Pb ages of 740 Ma and 725 Ma, respectively. The ages show that the LZC is composed mainly of Neoproterzoic acid and basic igneous rocks, suggesting that there is no Paleozoic active continental marginal rock association in the southern margin of the North China Block in northern part of the eastern Dabie Mountain. Based on the ages and combining the geological and geophysical analyses, the middle-low grade metamorphic rocks in the North Huiyang Belt (NHB) can be divided into three parts, which are the LZC composed mainly of the Neoproterzoic acid and basic igneous rocks, the Neoproterzoic Xianrechong formation and Xiangyunzhai formation and the Devonian Zhu- foan formation and Pangjialing formation of the foziling Group, and the suture zone between the Yongtze Block and the North China Block is inferred to be thrust under the NHB.

关键词： Dabie orogen, Luzhenguan Complex, U-Pb zircon age, Neoproterzoic.

Nanorocks, volatiles and plate tectonics

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Geoscience frontiers 2021年第5期12卷 202-214页

作者： Gautier Nicoli Silvio ferrero institut für geowissenschaften Universität Potsdam14476 Potsdam-GolmGermany Museum für Naturkunde(MfN) Leibniz-Institut für Evolutions-und Biodiversitätsforschung10115 BerlinGermany

The global geological volatile cycle(H,C,N)plays an important role in the long term self-regulation of the Earth ***,the complex interaction between its deep,solid Earth components(*** and mantle),Earth’s fluid envelopes(*** and hydrosphere)and plate tectonic processes is a subject of ongoing *** this study we want to draw attention to how the presence of primary melt(MI)and fluid(fI)inclusions in high-grade metamorphic minerals could help constrain the crustal component of the volatile *** that end,we review the distribution of MI and fI throughout Earth’s history,from ca.3.0 Ga ago up to the present *** argue that the lower crust might constitute an important,longterm,volatile storage unit,capable to influence the composition of the surface envelopes through the mean of weathering,crustal thickening,partial melting and crustal assimilation during volcanic *** with thermodynamic modelling,our compilation indicates that periods of well-established plate tectonic regimes atre prone to the reworking of supracrustal lithologies and the storage of volatiles in the lower *** hypothesis has implication beyond the scope of metamorphic petrology as it potentially links geodynamic mechanisms to habitable surface *** and fI in metamorphic crustal rocks then represent an invaluable archive to assess and quantify the co-joint evolution of plate tectonics and Earth’s external processes.

关键词： Nanorocks Plate tectonics Volatiles Lower crust

Age and Origin of Paleogene Granitoids from Western Yunnan Province,China:Geochemistry,SHrIMP Zircon Ages,and Hf-in-Zircon Isotopic Compositions

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Acta Geologica Sinica(English Edition) 2015年第5期89卷 1601-1615页

作者： SHI Yuruo WU Zhonghai Alfred KroNEr fAN Taoyuan YANG Zhenyu Beijing SHrIMP Center Institute of GeologyChinese Academy of Geological Sciences institute of Geomechanics Chinese Academy of Geological Sciences institut für geowissenschaften Universitat Mainz

We report geochemical data, SHrIMP zircon ages and Hf-in-zircon isotopic compositions for Cenozoic granitoids from major fault systems in the Tethyan belt in western Yunnan Province, southwestern *** magmatic pulses occurred in the Paleogene, namely at ca.57 Ma, ca.50 Ma, 45–40 Ma, and 38–34 *** magmatism of this episode（57–50 Ma） produced S-type granites whose zircons yielded εHf（t） values of-5.0 *** contrast, late magmatism of this episode reflects heterogeneous *** from a granite porphyry along the Ailaoshan-red river fault system have slightly positive εHf（t） values suggesting derivation from relatively young crust and/or a juvenile ***, zircons from a granite along the Gaoligong fault system have strongly negative εHf（t） values and suggest derivation from a Paleoproterozoic crustal *** composition of the granitoids varies with age（from ca.57 Ma to ca.34 Ma） from peraluminous to metaluminous and also suggests a change from syn-collisional to late-orogenic tectonic setting.A new tectonic model, impacting lithospheric wedge（ILW） is shown for the origin of Paleogene granitoids in this paper.

关键词： Paleogene magmatism SHrIMP zircon ages Hf-in-zircon isotopic compositions western Yunnan

ESr Dating of the Evolution of the Shuanghu Basin in the Northern Tibetan Plateau

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Acta Geologica Sinica(English Edition) 1999年第3期73卷 289-293页

作者： WU Zhenhan JIANG Wan Peter Blisniuk BI Siwen ZHANG Shukun Olaf Kuchel MAO Yi institute of Geomechcmics CAGS Minzu Xueyuan Nanlu Beijing 100081 institut für geowissenschaften Universitat Potsdam Postfach 601553 D-14415 Potsdam Germany

The Shuanghu basin is a NE-trending rift basin bounded by NE-striking normal faults and NW-striking shear-extensional faults of the northern Tibetan Plateau. four samples from calcite veins in marginal faults and one sample from mudstone (S-3) were collected for dating the evolution of the Shuanghu basin by using the ESr spectrograph of EXM-type. Ages were calculated according to the close-equilibrium model on the basis of the measured ESr signal spectra of samples, providing good chronological information. It is known from the ESr dating that the extensional faulting and rifting of the Shuanghu area began at 4.92 Ma B.P., followed by regional folding in 3.56–1.36 Ma, NW-striking faulting in 0.60 Ma and normal faulting in 0.024 Ma in the Shuanghu basin.

关键词： ESr dating tectonic events Shuanghu basin Tibetan Plateau.

Zircon and titanite geochronology of the f(u|¨)rstenstein granite massif,Bavarian forest,NW Bohemian Massif:Pulses of the late Variscan magmatic activity

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Zircon and titanite geochronology of the F(u|¨)rstenstein g...

Palynological investigation of a Holocene profile section from the Palaeo-Gaxun-Nur-Basin

中国科学院地质与地球物理研究所2004学术年会

作者： WOLfGANG SIEBEL institut fr geowissenschaften

The f(u|¨)rstenstein granite massif is the largest late Variscan granitoid body exposed in the Moldanubian basement of the Bavarian *** granite massif comprises different rock types,ranging from diorite to granite in *** study provides precise zircon and titanite ages,obtained by the U-Pb isotopic dilution and Pb-Pb evaporation methods,and Nd-Sr isotopic data on this *** dating constrains an intrusive sequence as following:Dioritic rocks crystallised about 334 to 332 Ma ago, earlier than the high-temperature peak stage of the Variscan metamorphism of the Moldanubian basement(325 to 320 Ma) in the Bavarian *** medium- to coarse-grained Tittling granite was emplaced about 10 Ma later,between 324 and 321 Ma,while the medium-grained Eberhardsreuth granite crystallised between 316 and 312 Ma,contemporaneously with the coarse-grained porphyritic Saldenburg *** from the dioritic rocks give U-Pb ages of about 321±4 Ma,indicating thermal resetting or crystallisation due to the intrusion of the Tittling *** diorites have initialε values of -1.3 to -2.9 and relatively low initial Sr/Sr ratios of 0.7056 to 0.7067,which suggest mantle contribution to melts or melting of young mafic lower *** granites have similar initialε values of -3.6 to -4.1 but show some variation in their Sr isotopic composition(initial Sr/Sr ratios of 0.7063 to 0.7074),probably indicating the involvement of crustal material in their genesis.

关键词： Bavarian forest fiirstenstein Variscan granite zircon age

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Chinese Science Bulletin 2003年第14期48卷 1418-1422页

作者： D.Demske S.Mischke institut f geologische Wissenschaften (Palntologie) FB Geowissenschaften Freie UniversitBerlin Malteser Str. 74-100 D 12249 Berlin Germany Institut f geologische Wissenschaften (Palntologie) FB Geowissenschaften Freie UniversitBerlin Malteser Str. 74-100 D 12249 Berlin Germany

Palynological investigations on lacustrine sediment samples revealed a general dominance of open Artemisia-Chenopodiaceae vegetation in the Palaeo-Gaxun- Nur-Basin (Inner Mongolia) between 5250 and 3500 cal. aBP. riverside woods (Hippopha? Populus) developed between 35003250 cal. aBP and reflect moister growing conditions. During the following moist-dry transition pronounced cooling occurred around 3000 cal. aBP, in upper elevations favouring the spread of montane woods (Picea, Betula). Aridity strongly increased from 2900 to 2700 cal. aBP. The recorded vegetational and environmental changes after 3500 cal. aBP can be correlated with glacier advances in the mountains and with a humid phase in the Tengger Shamo followed by desertification.

关键词：孢粉学全新世纵剖面湖泊沉积物中国内蒙古

Armoured mud balls as a result of ephemeral fluvial flood in a humid climate:Modern example from Guizhou Province,South China

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Journal of Palaeogeography 2014年第4期3卷 410-418页

作者： Gerhard H.Bachmann Martin-Luther-Universit?t Institut für GeowissenschaftenVon-Seckendorff-Platz 3D-06120 Halle (Saale)Halle (Saale)Germany

Armoured mud balls were observed after rainfall and a short flood in the otherwise dry Xiaohe （small river） valley of Guanling County, Guizhou Province, South China, approximately 30 km southwest of Guanling City. Armoured mud balls are most common in semiarid climates, but rather unusual in a humid climate as in Guizhou. A number of well-rounded mud balls, 2-20 cm in diameter, were found lying on the gravel of the Xiaohe gully floor. The mud balls consist of sticky, light brown and slightly mottled clay without carbonate content. The surfaces of the mud balls were studded with rims of sandor gravel-size limestone clasts, col- lected during bedload transport, as is typical for armoured mud balls. The mud balls originated from alluvial mudstone deposits of the valley floor and cliff that are most likely derived from the weathering and karstification of bedrock limestones. Such mudstones seem to be especially well suited for forming armoured mud balls. As flood events are rather common in the area, the formation of armoured mud balls should be very frequent in the Xiaohe valley and similar valleys nearby, giving the possibility for further and more detailed studies. To the best of our knowledge this is the first description of armoured mud balls in China.

关键词： armoured mud balls fluvial alluvial mudstones humid climate Guizhou South China

Carboniferous Alaskan-type complex along the Sino–Mongolian boundary,southern margin of the Central Asian Orogenic Belt

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Acta Geochimica 2017年第2期36卷 276-290页

作者： Yuruo Shi Linlin Li Alfred Kroner Jing Ding Wei Zhang Zengbao Huang Ping Jian Beijing SHrIMP Center Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China institut für geowissenschaften Universitat Mainz 55099 Mainz Germany Geological Survey of Gansu Province Lanzhou 735000 China

We present zircon ages and geochemical data for the Hongshishan Carboniferous Alaskan-type mafic–ultramafic complex exposed in the Beishan area along the Sino–Mongolian boundary, southern margin of the Central Asian Orogenic Belt. This complex mainly consists of dunite,harzburgite, lherzolite, wehrlite, and gabbro, which intrudes Early Carboniferous volcanic rocks and reveals a zoned structure. Zircons of a gabbro sample yielded a 206Pb/238 U age of 357 ± 4 Ma, reflecting the time of Early Carboniferous magmatism. Zircon ages were also obtained for an andesite(322 ± 3 Ma) and a basaltic andesite(304 ± 2 Ma).High initial Nd isotope whole-rock values suggest that the Hongshishan gabbro [e_(Nd(t))= +9.6-+10.2] and basalt[eNd(t)= +10.0-+10.8] were derived from a depleted mantle source. Slightly lower eNd(t)values for the ultramafic rocks [eNd(t)= +8.5-+8.7] suggest some interaction of the parental magma with the continental crust. In contrast, the Late Carboniferous Quershan samples in this area represent subduction-related arc volcanic rocks with Adakite-like compositions. The early Carboniferous Hongshishan Alaskan-type complex was interpreted to represent the remnants of a magma chamber that crystallized at the base of a mature island arc, whereas the Quershan island arc volcanic rockssuggest the resurrection of the subduction process after arccontinent collision and uplift of the roots of the arc.

关键词： Alaskan-type complex Carboniferous Zircon age Sino-Mongolian boundary CAOB

Synthesis of Ta C and Ta_2C from tantalum and graphite in the laser-heated diamond anvil cell

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Chinese Science Bulletin 2014年第36期59卷 5283-5289页

作者： Lkhamsuren Bayarjargal Bjrn Winkler Alexandra friedrich Erick A.Juarez-Arellano institut fr geowissenschaften Universitt FrankfurtAltenh ferallee 1 60438 Frankfurt am Main Germany Universidad del Papaloapan Circuito Central 200 Parque Industrial 68301 Tuxtepec Mexico

The pressure dependence of the onset of the formation of Ta C and Ta2 C from the elements has been investigated by in situ X-ray diffraction and *** C has been synthesized by the reaction of Ta and graphite at pressures between 8.6 and 14.3 GPa and at temperatures up to 2,300 K using a laser-heated diamond anvil cell. The products were characterized by X-ray diffraction. Ta and graphite begin to react around 1,100 K at ambient pressure conditions, and the reaction temperature increases with increasing pressure. A linear extrapolation of these data is consistent with recent observations of the formation of Ta C at 90 GPa and 3,600 K. We show that diffusion of carbon into tantalum significantly changes the lattice parameter of up to 2 % in the pressure range of up to19 GPa. In some experiments, Ta2 C was formed concomitantly. The experimentally determined bulk modulus of Ta2 C is B0;exp:= 286(5) GPa. Other tantalum carbide phases were not observed.

关键词：细胞合成激光加热碳化钽金刚石石墨原位X射线衍射压力依赖性反应温度