The east sector of the southern Qinling belt is, lithologically, composed mainly of metapelites, ***qüartzites, marbles and small amount of metabasites and gneisses, whose protoliths are the Silurian, Devonian an...The east sector of the southern Qinling belt is, lithologically, composed mainly of metapelites, ***qüartzites, marbles and small amount of metabasites and gneisses, whose protoliths are the Silurian, Devonian and less commonly the Sinian and Upper Palaeozoic. They have been subjected at least to two epochs of metamorphism. The early epoch belongs to progressive metamorphism which is centered on high amphibolite-granulite fades in the Fuping area and changed outwards into low amphibolite facies (staurolite-kyanite zone), epidote amphibolite facies (garnet zone) and greenschist facies (chlorite and biotite zones), the metamorphic age of which is about 220–260 Ma. This early-epoch metamorphism belongs to different pressure types: the rocks from greenschist to low amphibolite facies belong to the typical medium-pressure type which shows geothermal gradients of about 17–20 ***C/km and was probably produced by a crustal thickening process related to continental collision, and the high amphibolite-granulite facies belongs to the low-pressure type which shows geothermal gradients of about 25–38 ***C/km and was probably affected by some magmatic heats. Based on the basic characteristics of the P-T paths of the different facies calculated from the garnet zonations, it can be deduced that the metamorphism of medium-pressure facies series took place during an imbricated thickening process, rather than during the uplifting process after thickening. The late-epoch metamorphism belongs to dynamic metamorphism of greenschist facies which is overprinted on the early-epoch metamorphic rocks and is Yanshanian or Himalayan in age, probably related to intracontinental orogeny.展开更多
The Tianshan range could have been built by both late Early Paleozoicaccretion and Late Paleozoic collision events. The late Early Paleozoic Aqqikkudug-Weiya suture ismarked by Ordovician ophiolitic melange and a Silu...The Tianshan range could have been built by both late Early Paleozoicaccretion and Late Paleozoic collision events. The late Early Paleozoic Aqqikkudug-Weiya suture ismarked by Ordovician ophiolitic melange and a Silurian flysch sequence, high-pressure metamorphicrelics, and mylonitized rocks. The Central Tianshan belt could principally be an Ordovician volcanicarc; whereas the South Tianshan belt, a back-arc basin. Macro- and microstructures, along withunconformities, provide some kinematic and chronological constraints on 2-phase ductile deformation.The earlier ductile deformation occurring at ca. 400 Ma was marked by north-verging ductileshearing, yielding granulite-bearing ophiolitic melange blocks and garnet-pyroxene-facies ductiledeformation, and the later deformation, a dextral strike-slip tectonic process, occurred during theLate Carboniferous-Early Permian. Early Carboniferous molasses were deposited unconformably onpre-Carboniferous metamorphic and ductilely sheared rocks, implying the end of the early orogeny.The large-scale ductile strike-slip along the Aqqikkudug-Weiya zone was possibly caused by thesecond tectonic event, the Hercynian collision between the northern Tarim block and the southernSiberian block. Late Paleozoic granitic magmatism and superimposed structures overprinted this EarlyPaleozoic deformation belt. Results of geometric and kinematic studies suggest that the primaryframework of the Southern-Central Tianshan belt, at least the eastern part of the Tianshan belt, wasbuilt by these two phases of accretion events.展开更多
This paper discusses the relationship between the volume loss, fluid flow and component variations in the ductile shear zone of the southern Tan-Lu fault belt. The results show that there is a large amount of fluids f...This paper discusses the relationship between the volume loss, fluid flow and component variations in the ductile shear zone of the southern Tan-Lu fault belt. The results show that there is a large amount of fluids flowing through the shear zone during mylonitization, accompanied with the loss of volume of rocks and variations of elements and oxygen isotopes. The calculated temperature for mylonitization in different mylonites ranges from 446 to 484℃, corresponding to that of 475 to 500℃ for the wall rocks. The condition of differential stress during mylonization has been obtained between 99 and 210 MPa, whereas the differential stress in the wall rock gneiss is 70-78 MPa. The mylonites are enriched by factors of 1.32-1.87 in elements such as TiO2, P2O5, MnO, Y, Zr and V and depleted in SiO2, Na2O, K2O, Al203, Sr, Rb and light REEs compared to their protolith gneiss. The immobile element enrichments are attributed to enrichments in residual phases such as ilmentite, zircon, apatite and epidote in mylonites and are interpreted as due to volume losses from 15% to 60% in the ductile shear zone. The largest amount of SiO2 loss is 35.76 g/100 g in the ductile shear zone, which shows the fluid infiltration. Modeling calculated results of the fluid/rock ratio for the ductile shear zone range from 196 to 1192 by assuming different degrees of fluid saturation. Oxygen isotope changes of quartz and feldspar and the calculated fluid are corresponding to the variations of differential flow stress in the ductile shear zone. With increasing differential flow stress, the mylonites show a slight decrease of δ^18O in quartz, K-feldspar and fluid.展开更多
Continental reconstructions in Central Asia are represented by orogenesis along some large orogenic belts in the Altaid collage (Fig. 1 ) or Central Asian Orogenic Belt (CAOB), which separate the East European and...Continental reconstructions in Central Asia are represented by orogenesis along some large orogenic belts in the Altaid collage (Fig. 1 ) or Central Asian Orogenic Belt (CAOB), which separate the East European and Siberian cratons to the north from the Tarim and North China cratons to the south ($eng0r et al,, 1993; Jahn et al., 2004; Windley et al., 2007; Qu et al., 2008; Xiao et al., 2010; Xiao and Santosh, 2014). The Altaid Collage was characterized by complex long tectonic and structural evolution from at least ca. 1.0 Ga to late Paleozoic-early Mesozoic with considerable continental growth (Khain et al., 2002; Jahn et al., 2004; Xiao et al., 2009, 2014; KrOner et al., 2014), followed by Cenozoic intracontinental evolution related to far-field effect of the collision of the In- dian Plate to the Eurasian Accompanying with these complex world-class ore deposits developed 2001; Goldfarb et al., 2003, 2014). Plate (Cunningham, 2005). geodynamic evolutions, many (Qin, 2000; Yakubchuk et al,2001; Goldfarb et al., 2003, 2014).展开更多
The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the Northern Tianshan Mountain, along the southern margin of the Central Asian Orogenic Belt in northern Xinjiang autonomous region of Chi...The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the Northern Tianshan Mountain, along the southern margin of the Central Asian Orogenic Belt in northern Xinjiang autonomous region of China. The Sidingheishan intrusion is mainly composed of wehrlite, olivine websterite, olivine gabbro, gabbro and hornblende gabbro. At least two pulses of magma were involved in the formation of the intrusion. The first pulse of magma produced an olivine-free unit and the second pulse produced an olivine-bearing unit. The magmas intruded the Devonian granites and granodiorites.An age of 351.4±5.8 Ma(Early Carboniferous) for the Sidingheishan intrusion has been determined by U-Pb SHRIMP analysis of zircon grains separated from the olivine gabbro unit. A U-Pb age of 359.2±6.4 Ma from the gabbro unit has been obtained by LA-ICP-MS. Olivine of the Sidingheishan intrusion reaches 82.52 mole% Fo and 1414 ppm Ni. On the basis of olivine-liquid equilibria, it has been calculated that the MgO and FeO included in the parental magma of a wehrlite sample were approximately10.43 wt% and 13.14 wt%, respectively. The Sidingheishan intrusive rocks are characterized by moderate enrichments in Th and Sm, slight enrichments in light REE, and depletions in Nb, Ta, Zr and Hf. The εNd(t) values in the rock units vary from +6.70 to +9.64, and initial87Sr/86Sr ratios range between 0.7035 and0.7042. Initial206Pb/204Pb,207Pb/204Pb and208Pb/204Pb values fall in the ranges of 17.23-17.91,15.45-15.54 and 37.54-38.09 respectively. These characteristics are collectively similar to the Heishan intrusion and the Early Carboniferous subduction related volcanic rocks in the Santanghu Basin, North Tianshan and Beishan area. The low(La/Gd)PMvalues between 0.26 and 1.77 indicate that the magma of the Sidingheishan intrusion was most likely derived from a depleted spinel-peridotite mantle.(Th/Nb)PMratios from 0.59 to 20.25 indicate contamination of the parental magma in the upper crust.Crystallization modeling methods suggest that the parental magma of the Sidingheishan intrusion was generated by flush melting of the asthenosphere and subsequently there was about 10 vol%contamination from a granitic melt. This was followed by about 5 vol% assimilation of upper crustal rocks. Thus, the high-Mg basaltic parental magma of Sidingheishan intrusion is interpreted to have formed from partial melting of the asthenosphere during the break-off of a subducted slab.展开更多
The Yuxi (豫西) fold-thrust fracture belt is part of the gigantic fold-thrust fracture belt that extends NW in the southern North China plate. The contents of major elements of tectonites were analyzed by ICP-AES. T...The Yuxi (豫西) fold-thrust fracture belt is part of the gigantic fold-thrust fracture belt that extends NW in the southern North China plate. The contents of major elements of tectonites were analyzed by ICP-AES. The analysis of chemical compositions and new stress minerals indicates: extending from the surrounding country rocks to the center of the fracture belt, the Fe2O3 content gradually increases while the FeO content gradually decreases; regular increase, decrease or peak changes are shown for chemical compositions like SiO2, Al2O3, Fe2O3, MgO, CaO, FeO, loss on ignition, TIO:, K2O, Na2 O, etc.. New stress minerals are developed for the south branch and few for the north branch. The characteristics of chemical compositions and new stress minerals of the thrust fracture demonstrate that the fracture belt has undergone a process from a closed reducing environmental system to a relatively open. oxidizing environmental system, andcompressive fractures have resulted from compression in the late stages of evolution, and the dynamothermal metamorphism and thrusting intensities are different between the south and north branches of the belt, which is strong for the south branch but relatively weak for the north branch.展开更多
The Paleo-Tethys Ocean is usually interpreted as a Paleozoic ocean basin located between the Gondwana and Laurasia supercontinents. The Paleo-Tethyan orogenic record is well preserved in the Sanjiang area of SW China....The Paleo-Tethys Ocean is usually interpreted as a Paleozoic ocean basin located between the Gondwana and Laurasia supercontinents. The Paleo-Tethyan orogenic record is well preserved in the Sanjiang area of SW China. However, ophiolites are commonly dismembered in orogenic belt, and complete ophiolite sequences are rare in the Sanjiang area. The southern Lancangjiang belt is the most complicated tectonic complex of the Sanjiang Paleo-Tethyan orogen, SW China, and is key to understanding the evolution of the orogen. In this study, we focused on mafic–ultramafic rocks in the Yakou and Banpo areas of the southern Lancangjiang belt, of which newly discovered Yakou rocks show a complete ophiolite sequence. These rocks are composed of serpentinized peridotite, isotropic and cumulate gabbros, massive and pillow basalts, and plagiogranite. Whole-rock geochemical data indicate that these rocks were formed in an oceanic ridge setting, and they show depletions in Nb, Ta and Ti, and enrichment in Pb, suggesting a supra-subduction zone affinity of a back-arc setting. Furthermore, positive εNd(t)(+4.5 to +6.7) and zircon εHf(t) values(+12.4 to +14.3), as well as mantle-like δ18O values(~5.5‰), suggest that these rocks were derived from a long-term depleted mantle source. All of these features suggest that the Yakou mafic-ultramafic complex represents an ophiolite suite, making it the first complete ophiolite sequence to be discovered in the southern Lancangjiang orogenic belt. The Banpo complex gabbroic rocks have similar whole-rock geochemical and Sr-Nd isotopic, and zircon O-Hf isotopic compositions to those of the Yakou complex, suggesting an N-MORB affinity. Thus, maficultramafic rocks from the Banpo and Jinghong areas are most likely dismembered ophiolite suites. Considering these various characteristics, we consider that the Yakou, Banpo, and Jinghong mafic-ultramafic complexes represent an ophiolite belt but not a magmatic arc belt. SHRIMP zircon U-Pb dating yield weighted mean ages of 305±3 Ma, 310±2 Ma, and 313±6 Ma. Therefore, we suggest that the Banpo-Jinghong mafic-ultramafic complex represents a Late Carboniferous(313–305 Ma) ophiolite belt in the Sanjiang Paleo-Tethyan orogen of SW China. Finally, we propose that an arc-trench system could have developed in the Sanjiang Paleo-Tethyan orogenic belt of SW China during the Late Carboniferous.展开更多
The deep lateral growth process of the plateau is a hot topic in earth science.As the growth boundary zone of the northeastern Tibetan Plateau,southern Ningxia geomorphic zone is controlled by four major arcuate fault...The deep lateral growth process of the plateau is a hot topic in earth science.As the growth boundary zone of the northeastern Tibetan Plateau,southern Ningxia geomorphic zone is controlled by four major arcuate fault zones(Fig.1),namely Haiyuan fault(HYF),XiangshanTianjingshan fault(XTSF),Yantongshan fault(YTSF).展开更多
The objective of this article is to develop a groundwater flow model for a tannery belt using Visual MOD-FLOW Premium 4.4 for analyzing groundwater velocity and its response to various pumping strategies in two stages...The objective of this article is to develop a groundwater flow model for a tannery belt using Visual MOD-FLOW Premium 4.4 for analyzing groundwater velocity and its response to various pumping strategies in two stages, viz., steady and transient conditions. The steady state model was calibrated for April 2001, whereas the transient model was employed to forecast groundwater flow under various pumping strategies. The results showed that the total groundwater abstraction was about 80.43% of the groundwater recharge, but 10.25% was used up by evapotranspiration. The groundwater velocity, which is important for contaminant migration, varied from 0.21 to 0.52 m/d in the tannery cluster. The model was more sensitive to recharge from rainfall, hydraulic conductivity and specific yield. Finally, the model showed that the aquifer could sustain a pumping rate of 24892 m3/day without further decline in water level.展开更多
The Pontide belt in northern Turkey includes three major tectonic terranes,the Strandja Massif(Sj M),and the Istanbul(ISZ)and Sakarya Zones(SZ)(Fig.1).We present new age and geochemical data from ophiolites and ...The Pontide belt in northern Turkey includes three major tectonic terranes,the Strandja Massif(Sj M),and the Istanbul(ISZ)and Sakarya Zones(SZ)(Fig.1).We present new age and geochemical data from ophiolites and ophiolitic mélanges within the Sakarya Zone and show that these mafic–ultramafic rocks are the remnants of Tethyan oceanic lithosphere formed in different tectonic settings.The main ophiolite occurrences investigated in this study along the Karakaya Suture(KS)are associated with the latest Triassic Cimmeride orogeny,and in the Küre–Yusufeli ophiolite belt are part of the Alpide orogeny.The Karakaya Suture Zone ophiolites in northern west Turkey are comprised mainly of the Denizgoren(?anakkale)ophiolite,Bo?azk?y(Bursa),Geyve(Sakarya),Almac?k(Düzce)and?ele(Bolu)metaophiolites.The Denizg?ren ophiolite largely contains upper mantle peridotites,which are equivalents of the Permo–Triassic Lesvos peridotites and mélange units farther SW in the northern Aegean Sea.The Bo?azk?y ophiolite includes serpentinite and metagabbro,and the Almac?k and Geyve ophiolites display an almost complete Penrose–type sequence consisting of serpentinizeduppermantleperidotites,cumulate ultramafic–mafic rocks,isotropic gabbros,dolerite and plagiogranite dikes,and extrusive rocks.U–Pb zircon dating of plagiogranite dikes from?ele has revealed an igneous age of 260 Ma,and 255,235,227 Ma from Almac?k(Bozkurt et al.,2012a,b).Consistent with the previouslypublished Permo–Triassic age,we obtained a 268.4±6.3 Ma U–Pb zircon age from a plagiogranite dike within the Almacik ophiolite to the west.This KS ophiolite belt containing the?ele,Almac?k,Geyve ophiolites within the SZ extends westward into the Armutlu Peninsula and then into the Biga Peninsula(i.e.Denizg?ren ophiolite)and most likely connects with the remnants of the Triassic Meliata–Meliac ocean basin(Stampfli and Borel,2002)in the Balkan Peninsula.The KS ophiolites also continue eastward within the Pontide Belt into the Elekda?ophiolite(eastern Kastamonu)and then to the Refahiye ophiolite in NE Anatolia.Triassic granites in the SZ represent a magmatic arc that formed as a result of the northward subduction of the Izmir–Ankara–Erzincan oceanic lithosphere existing during the late Paleozoic through Cretaceous(Sarifakioglu et al.,2014)beneath the Pontides.We obtained a U–Pb zircon age of 231±2 Ma from a metagranitic intrusion into the Variscan basement of the SZ in the Kastamonu region of the central Pontides.This metagranite is enriched in LILE(Rb:63 ppm;Ba:65 ppm;Sr:200 ppm)and depleted in HFSE(Y:12.58 ppm;Yb:1.26 ppm;Ti O2:0.2 wt.%;Nb:7.6 ppm;Hf:3.9 ppm),characterizing it as subduction–related calc-alkaline pluton.Lead(3.9 ppm),U(1.6 ppm)and Ce(59 ppm)contents are interpreted as evidence for contamination by continental crust.The Küre basin to the north opened during the late Triassic to Liassic,following a backarc rifting episode in the central Pontides.Metabasic dike intrusions in the Devrekani metamorphic massif represent the first magmatic stage of this backarc rifting event.Whole-rock 40Ar-39Ar dating ofthe metabasic dikes has yielded cooling ages of 160.5±1.2 Ma. We infer that this age was reset due to thermal heating during the emplacement of the Middle Jurassic granitoids as the Küre oceanic basin was closing. The Küre ophiolite contains upper mantle peridotites and oceanic crustal rocks composed mainly of pillow–massive–breccia basalts, dacitic and rhyolitic lavas–tuffs, diabase dyke swarms, massive gabbros and a limited extent mafic cumulates. We obtained 182.6±1.9 Ma as a whole-rock 40Ar-39 Ar age from a pillow basalt and a U–Pb zircon age of 171±1 Ma from the granitic intrusion cross-cutting the peridotites. The easternmost representatives of the Küre ophiolite occur in the Yusufeli(Artvin) area in the eastern part of the Pontide belt. Here, oceanic crustal rocks are tectonically related to metamorphic rocks of the Variscan basement of the SZ. The ophiolitic crustal rocks contain isotropic gabbro and mafic and felsic dikes. Serpentinized upper mantle peridotites are scarce. Pillow lava basalts are overlain by a thick metasandstone–metashale association with locally foliated meta–lava and some manganiferous chert and mudstone interlayers. We obtained a U–Pb zircon age of 172.5±1.4 Ma from the granitic intrusion cross-cutting the Yusufeli ophiolite and of 181.9±0.9 Ma from a felsic dike(plagiogranite) in the Yusufeli ophiolite. The Middle Jurassic granites are related to the closure of the Küre-Yusufeli marginal ocean basin. The Küre and Yusufeli ophiolites have been previously interpreted as the remnants of the Paleotethys or the Intra-Pontide Ocean. However, we posit that these ophiolites represent amarginal, short-lived(;0 Ma) ocean basin, which opened during the late Triassic through Liassic, and then closed in Dogger. This oceanic lithosphere is similar to the Evros ophiolite in the northeastern Greece in terms of its ages and geochemical characteristics.展开更多
The southern segment of the North-South Seismic Belt in China is a critical region for earthquake preparedness and risk reduction efforts.However,limited by the low density of seismic stations and the use of single-pa...The southern segment of the North-South Seismic Belt in China is a critical region for earthquake preparedness and risk reduction efforts.However,limited by the low density of seismic stations and the use of single-parameter physical structural models,the deep tectonic features and seismogenic environment in this area remain controversial.Thus,a comprehensive analysis based on high-resolution crustal structures and multiple physical parameters is required.In this study,we applied the ambient noise tomography method to obtain the three-dimensional(3D)crustal S-wave velocity structure using continuous waveform data from 112 permanent stations and 350 densely distributed temporary stations in the southern segment of the North-South Seismic Belt.Then,we obtained the high-resolution 3D density structure through wavenumber-domain 3D gravity imaging constrained by the velocity structure.The low-velocity and low-density anomalies in the upper crust of the study area were mainly distributed in the Sichuan Basin and around Dali and Simao,while the high-velocity and high-density anomalies were primarily distributed in the Panxi region,corresponding to the surface geological features.Two prominent low-velocity and low-density anomalies were observed in the middle and lower crust:one to the west of the Songpan-Garzêblock and Sichuan-Yunnan diamond-shaped block,and the other near the Anninghe-Xiaojiang fault.Combined with the spatial distribution of seismic events in the study area,we found that previous earthquakes predominantly occurred in the transition zones between high and low anomaly regions and in the low-velocity and low-density zones in the upper crust.In contrast,moderate-to-strong earthquakes mainly occurred within the transition zones between high and low anomaly regions and close to the high-velocity and high-density regions,often with low-velocity and low-density layers below their hypocenters.Fluids play a critical role in the seismogenic process by reducing fault strength and destabilizing the stress state,which may be a triggering factor for earthquakes in the study area.Additionally,the upwelling of molten materials from the mantle may lead to energy accumulation and stress conce-ntration,providing an important seismogenic background for moderate-to-strong earthquakes in this area.展开更多
Objective The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the North Tianshan Mountains. This work used zircon U-Pb age data, bulk rock major and trace elements, Sr-Nd-Pb isotope data to ...Objective The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the North Tianshan Mountains. This work used zircon U-Pb age data, bulk rock major and trace elements, Sr-Nd-Pb isotope data to assess mantle source characteristics and crustal assimilation of the parental magma of the Sidingheishan intrusion. We have also discussed the tectonic evolution of the southern margin of the Central Asian Orogenic belt in the Late Paleozoic.展开更多
This paper re-describes the characteristics of pre-Ordovician (Pt3) metamorphic volcanic rocks in the Huimin-Manlai region of Yunnan Province from the aspects of petrographic characteristics, rock assemblage, petroche...This paper re-describes the characteristics of pre-Ordovician (Pt3) metamorphic volcanic rocks in the Huimin-Manlai region of Yunnan Province from the aspects of petrographic characteristics, rock assemblage, petrochemistry, REE, trace elements, lead isotopes and geotectonic setting. The metamorphic volcanic rocks maintain blasto-intergranular and blasto-andesitic textures; the volcanic rocks are characterized by a basalt-andesite-dacite assemblage; the volcanic rocks are basic-intermediate-intermediate-acid in chemical composition, belonging to semi-alkaline rocks, with calc-alkaline series and tholeiite series coexisting, and they are characterized by low TiO2 contents; their REE distribution patterns are of the LREE-enrichment right-inclined type; the volcanic rocks are enriched in large cation elements and commonly enriched in Th and partly depleted in Ti, Cr and P, belonging to the Gondwana type as viewed from their Pb isotopic composition; petrochemically the data points fall mostly within the field of island-arc volcanic rocks. All these characteristics provided new evidence for the existence of original Tethysan island-arc volcanic rocks in the region studied.展开更多
Within southern Mali, the Syama belt constitutes a linear major structure-oriented N-S, which host several gold deposits (e.g., Syama and Tabakoroni) and prospect areas (e.g. Tellem). The Syama Belt is formed by magma...Within southern Mali, the Syama belt constitutes a linear major structure-oriented N-S, which host several gold deposits (e.g., Syama and Tabakoroni) and prospect areas (e.g. Tellem). The Syama Belt is formed by magmatic rocks (basalts, lamprophyres, andesites, dacites and microgranites);sedimentary rocks (shales) and volcano-sedimentary rocks (pyroclastics). The magmatic rocks are divided into two main volcanic series: tholeiitic affinity rocks (basalts and lamprophyres) and calc-alkaline affinity (andesites) that are the most evolved. The field relationships between rocks of these two series suggest that the calc-alkaline series are younger the tholeiitic series. These tholeiitic series present the Mid-Ocean Ridge Basalt (MORB) affinity whereas the calc-alkaline series would be linked to an island arc-type. This coexistence is not an isolated case within the West African Craton (WAC). Otherwise, the Syama belt has all the characteristics of other belts, within which a number of gold deposits are developed, in the WAC.展开更多
The Belt and Road Initiative requires the urgent revival of the Southern Silk Road. This means a good understanding of its rich historical connotations and its comprehensive and mutual-beneficial functions. Starting f...The Belt and Road Initiative requires the urgent revival of the Southern Silk Road. This means a good understanding of its rich historical connotations and its comprehensive and mutual-beneficial functions. Starting from a very early period, the Southern Silk Road has played an important role in the history of Yunnan and has been characterized by using cowry as money. This paper proposes the development of a new economic corridor along the Southern Silk Road from Xi'an in the north, via Chengdu and Kunming, to South Asia and Southeast Asia thus linking the Silk Road Economic Belt to the 21 st Century Maritime Silk Road. This will bring about a new phase of all-around opening-up linking domestic and overseas markets via land and sea.展开更多
文摘The east sector of the southern Qinling belt is, lithologically, composed mainly of metapelites, ***qüartzites, marbles and small amount of metabasites and gneisses, whose protoliths are the Silurian, Devonian and less commonly the Sinian and Upper Palaeozoic. They have been subjected at least to two epochs of metamorphism. The early epoch belongs to progressive metamorphism which is centered on high amphibolite-granulite fades in the Fuping area and changed outwards into low amphibolite facies (staurolite-kyanite zone), epidote amphibolite facies (garnet zone) and greenschist facies (chlorite and biotite zones), the metamorphic age of which is about 220–260 Ma. This early-epoch metamorphism belongs to different pressure types: the rocks from greenschist to low amphibolite facies belong to the typical medium-pressure type which shows geothermal gradients of about 17–20 ***C/km and was probably produced by a crustal thickening process related to continental collision, and the high amphibolite-granulite facies belongs to the low-pressure type which shows geothermal gradients of about 25–38 ***C/km and was probably affected by some magmatic heats. Based on the basic characteristics of the P-T paths of the different facies calculated from the garnet zonations, it can be deduced that the metamorphism of medium-pressure facies series took place during an imbricated thickening process, rather than during the uplifting process after thickening. The late-epoch metamorphism belongs to dynamic metamorphism of greenschist facies which is overprinted on the early-epoch metamorphic rocks and is Yanshanian or Himalayan in age, probably related to intracontinental orogeny.
基金the supports from the National 973 Project on Westemn China (No.2001CB409804)the National Natural Science Foundation of China (grants 49772151 , 49832040)
文摘The Tianshan range could have been built by both late Early Paleozoicaccretion and Late Paleozoic collision events. The late Early Paleozoic Aqqikkudug-Weiya suture ismarked by Ordovician ophiolitic melange and a Silurian flysch sequence, high-pressure metamorphicrelics, and mylonitized rocks. The Central Tianshan belt could principally be an Ordovician volcanicarc; whereas the South Tianshan belt, a back-arc basin. Macro- and microstructures, along withunconformities, provide some kinematic and chronological constraints on 2-phase ductile deformation.The earlier ductile deformation occurring at ca. 400 Ma was marked by north-verging ductileshearing, yielding granulite-bearing ophiolitic melange blocks and garnet-pyroxene-facies ductiledeformation, and the later deformation, a dextral strike-slip tectonic process, occurred during theLate Carboniferous-Early Permian. Early Carboniferous molasses were deposited unconformably onpre-Carboniferous metamorphic and ductilely sheared rocks, implying the end of the early orogeny.The large-scale ductile strike-slip along the Aqqikkudug-Weiya zone was possibly caused by thesecond tectonic event, the Hercynian collision between the northern Tarim block and the southernSiberian block. Late Paleozoic granitic magmatism and superimposed structures overprinted this EarlyPaleozoic deformation belt. Results of geometric and kinematic studies suggest that the primaryframework of the Southern-Central Tianshan belt, at least the eastern part of the Tianshan belt, wasbuilt by these two phases of accretion events.
基金National Natural Science Foundation of China (Grant 40473021) the National 973- Project of the Ministry of Science and Technology of China (2003CB214600) the Foundation of the State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, and the jointed project of Max-Planck-Institute of Society and Chinese Academy of Sciences in Max-Planck-Institute of Nuclear Physics,Heidelberg, Germany.
文摘This paper discusses the relationship between the volume loss, fluid flow and component variations in the ductile shear zone of the southern Tan-Lu fault belt. The results show that there is a large amount of fluids flowing through the shear zone during mylonitization, accompanied with the loss of volume of rocks and variations of elements and oxygen isotopes. The calculated temperature for mylonitization in different mylonites ranges from 446 to 484℃, corresponding to that of 475 to 500℃ for the wall rocks. The condition of differential stress during mylonization has been obtained between 99 and 210 MPa, whereas the differential stress in the wall rock gneiss is 70-78 MPa. The mylonites are enriched by factors of 1.32-1.87 in elements such as TiO2, P2O5, MnO, Y, Zr and V and depleted in SiO2, Na2O, K2O, Al203, Sr, Rb and light REEs compared to their protolith gneiss. The immobile element enrichments are attributed to enrichments in residual phases such as ilmentite, zircon, apatite and epidote in mylonites and are interpreted as due to volume losses from 15% to 60% in the ductile shear zone. The largest amount of SiO2 loss is 35.76 g/100 g in the ductile shear zone, which shows the fluid infiltration. Modeling calculated results of the fluid/rock ratio for the ductile shear zone range from 196 to 1192 by assuming different degrees of fluid saturation. Oxygen isotope changes of quartz and feldspar and the calculated fluid are corresponding to the variations of differential flow stress in the ductile shear zone. With increasing differential flow stress, the mylonites show a slight decrease of δ^18O in quartz, K-feldspar and fluid.
基金financially supported by the Natural National Science Foundation of China(Grant Nos.41230207,41202150, 41472192,41390441 and 41190075)
文摘Continental reconstructions in Central Asia are represented by orogenesis along some large orogenic belts in the Altaid collage (Fig. 1 ) or Central Asian Orogenic Belt (CAOB), which separate the East European and Siberian cratons to the north from the Tarim and North China cratons to the south ($eng0r et al,, 1993; Jahn et al., 2004; Windley et al., 2007; Qu et al., 2008; Xiao et al., 2010; Xiao and Santosh, 2014). The Altaid Collage was characterized by complex long tectonic and structural evolution from at least ca. 1.0 Ga to late Paleozoic-early Mesozoic with considerable continental growth (Khain et al., 2002; Jahn et al., 2004; Xiao et al., 2009, 2014; KrOner et al., 2014), followed by Cenozoic intracontinental evolution related to far-field effect of the collision of the In- dian Plate to the Eurasian Accompanying with these complex world-class ore deposits developed 2001; Goldfarb et al., 2003, 2014). Plate (Cunningham, 2005). geodynamic evolutions, many (Qin, 2000; Yakubchuk et al,2001; Goldfarb et al., 2003, 2014).
基金financially supported by the National Science Foundation of China (41402070, 41602082, 4170021021)China Geological Survey (DD20160346)
文摘The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the Northern Tianshan Mountain, along the southern margin of the Central Asian Orogenic Belt in northern Xinjiang autonomous region of China. The Sidingheishan intrusion is mainly composed of wehrlite, olivine websterite, olivine gabbro, gabbro and hornblende gabbro. At least two pulses of magma were involved in the formation of the intrusion. The first pulse of magma produced an olivine-free unit and the second pulse produced an olivine-bearing unit. The magmas intruded the Devonian granites and granodiorites.An age of 351.4±5.8 Ma(Early Carboniferous) for the Sidingheishan intrusion has been determined by U-Pb SHRIMP analysis of zircon grains separated from the olivine gabbro unit. A U-Pb age of 359.2±6.4 Ma from the gabbro unit has been obtained by LA-ICP-MS. Olivine of the Sidingheishan intrusion reaches 82.52 mole% Fo and 1414 ppm Ni. On the basis of olivine-liquid equilibria, it has been calculated that the MgO and FeO included in the parental magma of a wehrlite sample were approximately10.43 wt% and 13.14 wt%, respectively. The Sidingheishan intrusive rocks are characterized by moderate enrichments in Th and Sm, slight enrichments in light REE, and depletions in Nb, Ta, Zr and Hf. The εNd(t) values in the rock units vary from +6.70 to +9.64, and initial87Sr/86Sr ratios range between 0.7035 and0.7042. Initial206Pb/204Pb,207Pb/204Pb and208Pb/204Pb values fall in the ranges of 17.23-17.91,15.45-15.54 and 37.54-38.09 respectively. These characteristics are collectively similar to the Heishan intrusion and the Early Carboniferous subduction related volcanic rocks in the Santanghu Basin, North Tianshan and Beishan area. The low(La/Gd)PMvalues between 0.26 and 1.77 indicate that the magma of the Sidingheishan intrusion was most likely derived from a depleted spinel-peridotite mantle.(Th/Nb)PMratios from 0.59 to 20.25 indicate contamination of the parental magma in the upper crust.Crystallization modeling methods suggest that the parental magma of the Sidingheishan intrusion was generated by flush melting of the asthenosphere and subsequently there was about 10 vol%contamination from a granitic melt. This was followed by about 5 vol% assimilation of upper crustal rocks. Thus, the high-Mg basaltic parental magma of Sidingheishan intrusion is interpreted to have formed from partial melting of the asthenosphere during the break-off of a subducted slab.
基金This paper is supported by the Key Basic Research Project funded by theChinese Academy of Sciences (No . KZCX2-SW-117) .
文摘The Yuxi (豫西) fold-thrust fracture belt is part of the gigantic fold-thrust fracture belt that extends NW in the southern North China plate. The contents of major elements of tectonites were analyzed by ICP-AES. The analysis of chemical compositions and new stress minerals indicates: extending from the surrounding country rocks to the center of the fracture belt, the Fe2O3 content gradually increases while the FeO content gradually decreases; regular increase, decrease or peak changes are shown for chemical compositions like SiO2, Al2O3, Fe2O3, MgO, CaO, FeO, loss on ignition, TIO:, K2O, Na2 O, etc.. New stress minerals are developed for the south branch and few for the north branch. The characteristics of chemical compositions and new stress minerals of the thrust fracture demonstrate that the fracture belt has undergone a process from a closed reducing environmental system to a relatively open. oxidizing environmental system, andcompressive fractures have resulted from compression in the late stages of evolution, and the dynamothermal metamorphism and thrusting intensities are different between the south and north branches of the belt, which is strong for the south branch but relatively weak for the north branch.
基金supported by the National Natural Science Foundation of China(Grant Nos.91755103 and 41872240)the Ministry of Science and Technology of China(2016YFC0600304)+1 种基金the Chinese Geological Survey Project(Grant Nos.DD20190370 and DD20190060)the Institute of Geology of the Chinese Academy of Geological Sciences Research Fund(Grant Nos.J1705 and YYWF201704)
文摘The Paleo-Tethys Ocean is usually interpreted as a Paleozoic ocean basin located between the Gondwana and Laurasia supercontinents. The Paleo-Tethyan orogenic record is well preserved in the Sanjiang area of SW China. However, ophiolites are commonly dismembered in orogenic belt, and complete ophiolite sequences are rare in the Sanjiang area. The southern Lancangjiang belt is the most complicated tectonic complex of the Sanjiang Paleo-Tethyan orogen, SW China, and is key to understanding the evolution of the orogen. In this study, we focused on mafic–ultramafic rocks in the Yakou and Banpo areas of the southern Lancangjiang belt, of which newly discovered Yakou rocks show a complete ophiolite sequence. These rocks are composed of serpentinized peridotite, isotropic and cumulate gabbros, massive and pillow basalts, and plagiogranite. Whole-rock geochemical data indicate that these rocks were formed in an oceanic ridge setting, and they show depletions in Nb, Ta and Ti, and enrichment in Pb, suggesting a supra-subduction zone affinity of a back-arc setting. Furthermore, positive εNd(t)(+4.5 to +6.7) and zircon εHf(t) values(+12.4 to +14.3), as well as mantle-like δ18O values(~5.5‰), suggest that these rocks were derived from a long-term depleted mantle source. All of these features suggest that the Yakou mafic-ultramafic complex represents an ophiolite suite, making it the first complete ophiolite sequence to be discovered in the southern Lancangjiang orogenic belt. The Banpo complex gabbroic rocks have similar whole-rock geochemical and Sr-Nd isotopic, and zircon O-Hf isotopic compositions to those of the Yakou complex, suggesting an N-MORB affinity. Thus, maficultramafic rocks from the Banpo and Jinghong areas are most likely dismembered ophiolite suites. Considering these various characteristics, we consider that the Yakou, Banpo, and Jinghong mafic-ultramafic complexes represent an ophiolite belt but not a magmatic arc belt. SHRIMP zircon U-Pb dating yield weighted mean ages of 305±3 Ma, 310±2 Ma, and 313±6 Ma. Therefore, we suggest that the Banpo-Jinghong mafic-ultramafic complex represents a Late Carboniferous(313–305 Ma) ophiolite belt in the Sanjiang Paleo-Tethyan orogen of SW China. Finally, we propose that an arc-trench system could have developed in the Sanjiang Paleo-Tethyan orogenic belt of SW China during the Late Carboniferous.
基金supported by the Geological Survey Project of China Geological Survey(Grant No.DD20190018)
文摘The deep lateral growth process of the plateau is a hot topic in earth science.As the growth boundary zone of the northeastern Tibetan Plateau,southern Ningxia geomorphic zone is controlled by four major arcuate fault zones(Fig.1),namely Haiyuan fault(HYF),XiangshanTianjingshan fault(XTSF),Yantongshan fault(YTSF).
文摘The objective of this article is to develop a groundwater flow model for a tannery belt using Visual MOD-FLOW Premium 4.4 for analyzing groundwater velocity and its response to various pumping strategies in two stages, viz., steady and transient conditions. The steady state model was calibrated for April 2001, whereas the transient model was employed to forecast groundwater flow under various pumping strategies. The results showed that the total groundwater abstraction was about 80.43% of the groundwater recharge, but 10.25% was used up by evapotranspiration. The groundwater velocity, which is important for contaminant migration, varied from 0.21 to 0.52 m/d in the tannery cluster. The model was more sensitive to recharge from rainfall, hydraulic conductivity and specific yield. Finally, the model showed that the aquifer could sustain a pumping rate of 24892 m3/day without further decline in water level.
基金supported by a grant from the General Directorate of Mineral Research and Exploration of Turkey (MTA, Ankara project no: 2009.30.14.09.4+1 种基金 2010.30.14.08.32011.30.14.08.3)
文摘The Pontide belt in northern Turkey includes three major tectonic terranes,the Strandja Massif(Sj M),and the Istanbul(ISZ)and Sakarya Zones(SZ)(Fig.1).We present new age and geochemical data from ophiolites and ophiolitic mélanges within the Sakarya Zone and show that these mafic–ultramafic rocks are the remnants of Tethyan oceanic lithosphere formed in different tectonic settings.The main ophiolite occurrences investigated in this study along the Karakaya Suture(KS)are associated with the latest Triassic Cimmeride orogeny,and in the Küre–Yusufeli ophiolite belt are part of the Alpide orogeny.The Karakaya Suture Zone ophiolites in northern west Turkey are comprised mainly of the Denizgoren(?anakkale)ophiolite,Bo?azk?y(Bursa),Geyve(Sakarya),Almac?k(Düzce)and?ele(Bolu)metaophiolites.The Denizg?ren ophiolite largely contains upper mantle peridotites,which are equivalents of the Permo–Triassic Lesvos peridotites and mélange units farther SW in the northern Aegean Sea.The Bo?azk?y ophiolite includes serpentinite and metagabbro,and the Almac?k and Geyve ophiolites display an almost complete Penrose–type sequence consisting of serpentinizeduppermantleperidotites,cumulate ultramafic–mafic rocks,isotropic gabbros,dolerite and plagiogranite dikes,and extrusive rocks.U–Pb zircon dating of plagiogranite dikes from?ele has revealed an igneous age of 260 Ma,and 255,235,227 Ma from Almac?k(Bozkurt et al.,2012a,b).Consistent with the previouslypublished Permo–Triassic age,we obtained a 268.4±6.3 Ma U–Pb zircon age from a plagiogranite dike within the Almacik ophiolite to the west.This KS ophiolite belt containing the?ele,Almac?k,Geyve ophiolites within the SZ extends westward into the Armutlu Peninsula and then into the Biga Peninsula(i.e.Denizg?ren ophiolite)and most likely connects with the remnants of the Triassic Meliata–Meliac ocean basin(Stampfli and Borel,2002)in the Balkan Peninsula.The KS ophiolites also continue eastward within the Pontide Belt into the Elekda?ophiolite(eastern Kastamonu)and then to the Refahiye ophiolite in NE Anatolia.Triassic granites in the SZ represent a magmatic arc that formed as a result of the northward subduction of the Izmir–Ankara–Erzincan oceanic lithosphere existing during the late Paleozoic through Cretaceous(Sarifakioglu et al.,2014)beneath the Pontides.We obtained a U–Pb zircon age of 231±2 Ma from a metagranitic intrusion into the Variscan basement of the SZ in the Kastamonu region of the central Pontides.This metagranite is enriched in LILE(Rb:63 ppm;Ba:65 ppm;Sr:200 ppm)and depleted in HFSE(Y:12.58 ppm;Yb:1.26 ppm;Ti O2:0.2 wt.%;Nb:7.6 ppm;Hf:3.9 ppm),characterizing it as subduction–related calc-alkaline pluton.Lead(3.9 ppm),U(1.6 ppm)and Ce(59 ppm)contents are interpreted as evidence for contamination by continental crust.The Küre basin to the north opened during the late Triassic to Liassic,following a backarc rifting episode in the central Pontides.Metabasic dike intrusions in the Devrekani metamorphic massif represent the first magmatic stage of this backarc rifting event.Whole-rock 40Ar-39Ar dating ofthe metabasic dikes has yielded cooling ages of 160.5±1.2 Ma. We infer that this age was reset due to thermal heating during the emplacement of the Middle Jurassic granitoids as the Küre oceanic basin was closing. The Küre ophiolite contains upper mantle peridotites and oceanic crustal rocks composed mainly of pillow–massive–breccia basalts, dacitic and rhyolitic lavas–tuffs, diabase dyke swarms, massive gabbros and a limited extent mafic cumulates. We obtained 182.6±1.9 Ma as a whole-rock 40Ar-39 Ar age from a pillow basalt and a U–Pb zircon age of 171±1 Ma from the granitic intrusion cross-cutting the peridotites. The easternmost representatives of the Küre ophiolite occur in the Yusufeli(Artvin) area in the eastern part of the Pontide belt. Here, oceanic crustal rocks are tectonically related to metamorphic rocks of the Variscan basement of the SZ. The ophiolitic crustal rocks contain isotropic gabbro and mafic and felsic dikes. Serpentinized upper mantle peridotites are scarce. Pillow lava basalts are overlain by a thick metasandstone–metashale association with locally foliated meta–lava and some manganiferous chert and mudstone interlayers. We obtained a U–Pb zircon age of 172.5±1.4 Ma from the granitic intrusion cross-cutting the Yusufeli ophiolite and of 181.9±0.9 Ma from a felsic dike(plagiogranite) in the Yusufeli ophiolite. The Middle Jurassic granites are related to the closure of the Küre-Yusufeli marginal ocean basin. The Küre and Yusufeli ophiolites have been previously interpreted as the remnants of the Paleotethys or the Intra-Pontide Ocean. However, we posit that these ophiolites represent amarginal, short-lived(;0 Ma) ocean basin, which opened during the late Triassic through Liassic, and then closed in Dogger. This oceanic lithosphere is similar to the Evros ophiolite in the northeastern Greece in terms of its ages and geochemical characteristics.
基金This research was jointly funded by the National Key R&D Program of China(No.2021YFA0715101)the National Natural Science Foundation of China(Nos.41974101 and 41774098)the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences.We thank the two anonymous reviewers and the associate editor for their precious comments and suggestions。
文摘The southern segment of the North-South Seismic Belt in China is a critical region for earthquake preparedness and risk reduction efforts.However,limited by the low density of seismic stations and the use of single-parameter physical structural models,the deep tectonic features and seismogenic environment in this area remain controversial.Thus,a comprehensive analysis based on high-resolution crustal structures and multiple physical parameters is required.In this study,we applied the ambient noise tomography method to obtain the three-dimensional(3D)crustal S-wave velocity structure using continuous waveform data from 112 permanent stations and 350 densely distributed temporary stations in the southern segment of the North-South Seismic Belt.Then,we obtained the high-resolution 3D density structure through wavenumber-domain 3D gravity imaging constrained by the velocity structure.The low-velocity and low-density anomalies in the upper crust of the study area were mainly distributed in the Sichuan Basin and around Dali and Simao,while the high-velocity and high-density anomalies were primarily distributed in the Panxi region,corresponding to the surface geological features.Two prominent low-velocity and low-density anomalies were observed in the middle and lower crust:one to the west of the Songpan-Garzêblock and Sichuan-Yunnan diamond-shaped block,and the other near the Anninghe-Xiaojiang fault.Combined with the spatial distribution of seismic events in the study area,we found that previous earthquakes predominantly occurred in the transition zones between high and low anomaly regions and in the low-velocity and low-density zones in the upper crust.In contrast,moderate-to-strong earthquakes mainly occurred within the transition zones between high and low anomaly regions and close to the high-velocity and high-density regions,often with low-velocity and low-density layers below their hypocenters.Fluids play a critical role in the seismogenic process by reducing fault strength and destabilizing the stress state,which may be a triggering factor for earthquakes in the study area.Additionally,the upwelling of molten materials from the mantle may lead to energy accumulation and stress conce-ntration,providing an important seismogenic background for moderate-to-strong earthquakes in this area.
基金financially supported by the National Science Foundation of China(grants No.41402070, 41372101 and 41602082)China Geological Survey (grant No.DD20160346)
文摘Objective The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the North Tianshan Mountains. This work used zircon U-Pb age data, bulk rock major and trace elements, Sr-Nd-Pb isotope data to assess mantle source characteristics and crustal assimilation of the parental magma of the Sidingheishan intrusion. We have also discussed the tectonic evolution of the southern margin of the Central Asian Orogenic belt in the Late Paleozoic.
基金This research was granted by the National Natural Science Foundation of China (Grant No. 40372105).
文摘This paper re-describes the characteristics of pre-Ordovician (Pt3) metamorphic volcanic rocks in the Huimin-Manlai region of Yunnan Province from the aspects of petrographic characteristics, rock assemblage, petrochemistry, REE, trace elements, lead isotopes and geotectonic setting. The metamorphic volcanic rocks maintain blasto-intergranular and blasto-andesitic textures; the volcanic rocks are characterized by a basalt-andesite-dacite assemblage; the volcanic rocks are basic-intermediate-intermediate-acid in chemical composition, belonging to semi-alkaline rocks, with calc-alkaline series and tholeiite series coexisting, and they are characterized by low TiO2 contents; their REE distribution patterns are of the LREE-enrichment right-inclined type; the volcanic rocks are enriched in large cation elements and commonly enriched in Th and partly depleted in Ti, Cr and P, belonging to the Gondwana type as viewed from their Pb isotopic composition; petrochemically the data points fall mostly within the field of island-arc volcanic rocks. All these characteristics provided new evidence for the existence of original Tethysan island-arc volcanic rocks in the region studied.
文摘Within southern Mali, the Syama belt constitutes a linear major structure-oriented N-S, which host several gold deposits (e.g., Syama and Tabakoroni) and prospect areas (e.g. Tellem). The Syama Belt is formed by magmatic rocks (basalts, lamprophyres, andesites, dacites and microgranites);sedimentary rocks (shales) and volcano-sedimentary rocks (pyroclastics). The magmatic rocks are divided into two main volcanic series: tholeiitic affinity rocks (basalts and lamprophyres) and calc-alkaline affinity (andesites) that are the most evolved. The field relationships between rocks of these two series suggest that the calc-alkaline series are younger the tholeiitic series. These tholeiitic series present the Mid-Ocean Ridge Basalt (MORB) affinity whereas the calc-alkaline series would be linked to an island arc-type. This coexistence is not an isolated case within the West African Craton (WAC). Otherwise, the Syama belt has all the characteristics of other belts, within which a number of gold deposits are developed, in the WAC.
文摘The Belt and Road Initiative requires the urgent revival of the Southern Silk Road. This means a good understanding of its rich historical connotations and its comprehensive and mutual-beneficial functions. Starting from a very early period, the Southern Silk Road has played an important role in the history of Yunnan and has been characterized by using cowry as money. This paper proposes the development of a new economic corridor along the Southern Silk Road from Xi'an in the north, via Chengdu and Kunming, to South Asia and Southeast Asia thus linking the Silk Road Economic Belt to the 21 st Century Maritime Silk Road. This will bring about a new phase of all-around opening-up linking domestic and overseas markets via land and sea.
基金国家自然科学基金(42102260、41730213、41890831、42072267、41972229)长安大学中央高校基本科研业务专项资金-高新技术研究支持计划培养项目(300102272204)+1 种基金裘搓基金会Croucher Chinese Visitorships(2022-2023)陕西高校青年创新团队The Youth Innovation Team of Shaanxi Universities联合资助。