Regional Brand and High-quality Development of Fruits in Ethnic Areas of the Yangtze River Economic Belt under the Greater Food Approach

Establishing the Greater Food Approach and promoting the Yangtze River Economic Belt s national major regional development strategy can better support and serve the agricultural power and Chinese-style modernization.This paper introduces the characteristics of fruit industry in 16 autonomous prefectures and 47 autonomous counties under the jurisdiction of the Yangtze River Economic Belt.It studies the intellectual property resources of brand marks from the aspects of geographical indications,collective trademarks,certification trademarks,well-known trademarks in China and national design patents,and analyzes the main problems of brand and high-quality development of fruit industry in these ethnic autonomous areas.Finally,it puts forward some strategies,such as improving the protection of intellectual property rights of geographical indications,using intellectual property rights of brand signs,building modern seed industry upgrading project,drawing lessons from the experience of thousand villages demonstration project,ensuring that large-scale poverty does not occur,and building a diversified food supply system.

Promoting High-quality Development of Grain and Oil in Ethnic Areas of the Yangtze River Economic Belt from the Perspective of Agricultural Power

Accelerating the construction of agricultural power,further promoting the high-quality development of the Yangtze River Economic Belt,and better supporting and serving Chinese-style modernization are the key issues at present.This paper first introduces the Yangtze River Economic Belt and its ethnic areas,and studies the characteristics of the grain and oil industry in the ethnic autonomous areas of the economic belt,as well as the current situation of various types of intellectual property resources,such as industrial cultural heritage,scientific and tech-nological innovation,and brand marking intellectual property.Besides,it analyzes the main problems in the high-quality development of grain and oil in the Yangtze River Economic Belt ethnic areas.Finally,it comes up with recommendations,including protecting the intellectual prop-erty rights of cultural heritage in the field of grain and oil,leading the inheritance and development of excellent traditional Chinese culture,use scientific and technological innovation intellectual property rights to promote the innovation-driven development strategy of the grain and oil in-dustry,and providing counterpart assistance to ethnic autonomous areas in the Yangtze River Economic Belt to further promote the high-quality development of the Yangtze River Economic Belt.

Geological Fluid Mapping in the Tongling Area:Implications for the Paleozoic Submarine Hydrothermal System in the Middle-Lower Yangtze Metallogenic Belt,East China

The Tongling area is one of the 7 ore-cluster areas in the Middle-Lower Yangtze metallogenic belt, East China, and has tectonically undergone a long-term geologic history from the late Paleozoic continental rifting, through the Middle Triassic continent-continent collision to the Jurassic-Cretaceous intracontinental tectono-magmatic activation. The Carboniferous sedimentary-exhalative processes in the area produced widespread massive sulfides with ages of 303-321 Ma, which partly formed massive pyrite-Cu deposits, but mostly provided significant sulfur and metals to the skarn Cu mineralization associated with the Yanshanian felsic intrusions.To understand the Carboniferous submarine hydrothermal system, an area of about 1046 km^2 was chosen to carry out the geological fluid mapping. Associated with massive sulfide formation, footwall sequences 948 m to 1146 m thick, composed of the Lower Silurian-Upper Devonian sandstone, siltstone and thin-layered shale, were widely altered. This hydrothermal alteration is interpreted to reflect largescale hydrothermal fluid flow associated with the late Paleozoic crustal rifting and subsidence. Three hydrothermal alteration types, i.e., deep-level semiconformable siliclfication （S1）, fracture-controlled quartz-sericite-pyrite alteration （S2-3）, and upper-level sub-discordant quartz-sericite-chlorite alteration （D3）, were developed to form distinct zones in the mapped area. About 50-m thick semiconformable silicification zones are located at -1-km depth below massive sulfides and developed between an impermeable shale caprock （S1） and the underlying Ordovician unaltered limestone. Comparisons with modern geothermal systems suggest that the alteration zones record a sub-seafioor aquifer with the most productive hydrothermal fluid flow. Fracture-controlled quartz-sericite-pyrite alteration formed transgressive zones, which downward crosscut the semiconformable alteration zones, and upwards grade into sub-discordant alteration zones that enveloped no economic stringer- stockwork zones beneath massive sulfides. This transgressive zone likely marks an upfiow path of high- flux fluids from the hydrothermal aquifer. Lateral zonation of the sub-discordant alteration zones and their relationship to overlying massive sulfide lenses suggest lateral flows and diffusive discharging of the hydrothermal fluids in a permeable sandstone sequence. Three large-sized, 14 middle-small massive sulfide deposits, and 40 massive sulfide sites have been mapped in detail. They show regional strata- bound characters and two major styles, i.e., the layered sheet plus strata-bound stringer-style and the mound-style. Associated exhalite and chemical sedimentary rock suites include （1） anhydrite-barite, （2） jasper-chert, （3） Mg-rich mudstone-pyrite shale, （4） barite lens, （5） siderite-Fe-bearing dolomite, and （6） Mn-rich shale-mudstone, which usually comprise three sulfide-exhalite cyclic units in the area.The spatial distribution of these alteration zones （minerals） and associated massive sulfdes and exhalites, and regional variation in δ^34S of hydrothermal pyrite and in δ^18O-δ^34C of hanging wall carbonates, suggest three WNW-extending domains of fluid flow, controlled by the basement faults and syn-depositional faults. Each fluid domain appears to have at least two upflow zones, with estimated even spacing of about 5-8 km in the mapped area. The repeated appearance of sulfide-sulfate or sulfide-carbonate rhythmic units in the area suggests episodically venting of fluids through the upfiow conduits by breaking the overlying seals of the hydrothermal aquifer.

In Situ Analyses of Trace Elements, U–Pb and Lu–Hf Isotopes in Zircons from the Tongshankou Granodiorite Porphyry in Southeast Hubei Province, Middle-Lower Yangtze River Metallogenic Belt, China

The Tongshankou Cu-Mo deposit, located in southeast Hubei province, is a typical skarn–porphyry type ore deposit closely related to the Tongshankou granodiorite porphyry, characterized by a high Sr/Y ratio.Detailed in situ analyses of the trace elements and U–Pb and Lu–Hf isotopes in zircons from the Tongshankou granodiorite porphyry were performed.Scarcely any inherited zircons were observed, and the analyzed zircons yielded highly concordant results with a weighted mean 206Pb/238 U age of 143.5 ± 0.45 Ma（n=20, mean square weighted deviation was 0.75）, which was interpreted to represent the crystallization age of the Tongshankou granodiorite porphyry.The chondrite-normalized rare-earth element pattern was characterized by a slope that steeply rises from the light-group rare-earth elements（LREE） to the heavy-group rare-earth elements（HREE） with a positive Ce-anomaly and inconspicuous Eu-anomaly, which was coincident with the pattern of the zircons from the Chuquicamata West porphyry, Chile.The analyzed zircons also had relatively low 176Hf/177 Hf ratios of 0.282526–0.282604.Assuming t=143 Ma, the corresponding calculated initial Hf isotope compositions（εHf（t）） ranged from-5.6 to-2.9.The results of the in situ analysis of trace elements and U–Pb and Lu–Hf isotopes in zircons from the Tongshankou granodiorite porphyry suggest that a deep-seated process involving a thickened-crust/enriched-mantle interaction may play an important role in the generation of high Sr/Y-ratio magma and potentially in the generation of porphyry Cu-Mo systems.

Late Mesozoic Ore-forming Events in the Ningwu Ore District, Middle-Lower Yangtze River Polymetallic Ore Belt, East China: Evidence from Zircon U-Pb Geochronology and Hf Isotopic Compositions of the Granodioritic Stocks

Late Mesozoic volcanic-subvolcanic rocks and related iron deposits, known as porphyry iron deposits in China, are widespread in the Ningwu ore district （Cretaceous basin） of the middle-lower Yangtze River polymetallic ore belt, East China. Two types of Late Mesozoic magmatic rocks are exposed： one is dioritic rocks closely related to iron mineralization as the hosted rock, and the other one is granodioritic （-granitic） rocks that cut the ore bodies. To understand the age of the iron mineralization and the ore-forming event, detailed zircon U-Pb dating and Hf isotope measurement were performed on granodioritic stocks in the Washan, Gaocun-Nanshan, Dongshan and Heshangqiao iron deposits in the basin. Four emplacement and crystallization （typically for zircons） ages of granodioritic rocks were measured as 126.1±0.5 Ma, 126.8±0.5 Ma, 127.3±0.5 Ma and 126.3±0.4 Ma, respectively in these four deposits, with the LA-MC-ICP-MS zircon U-Pb method. Based on the above results combined with previous dating, it is inferred that the iron deposits in the Ningwu Cretaceous basin occurred in a very short period of 131-127 Ma. In situ zircon Hf compositions of εHf（t） of the granodiorite are mainly from -3 to -8 and their corresponding 176Hf/177Hf ratio are from 0.28245 to 0.28265, indicating similar characteristics of dioritic rocks in the basin. We infer that granodioritic rocks occurring in the Ningwu ore district have an original relationship with dioritic rocks. These new results provide significant evidence for further study of this ore district so as to understand the ore-forming event in the study area.

Cathodoluminescence and Trace Element Composition of Scheelite from the Middle-Lower Yangtze River Metallogenic Belt(MLYB): Implications for Mineralization and Exploration

The Middle-Lower Yangtze River Metallogenic Belt(MLYB)is known to contain abundant copper and iron porphyry-skarn deposits,with an increasing number of tungsten deposits and scheelite in Fe-Cu deposits being discovered in the MLYB during recent decades.The ore genesis of the newly-discovered tungsten mineralization in the MLYB is poorly understood.We investigate four sets of scheelite samples from tungsten,iron and copper deposits,using CL imaging and LA-ICP-MS techniques to reveal internal zonation patterns and trace element compositions.The REE distribution patterns of four studied deposits show varying degrees of LREE enrichment with negative Eu anomalies.The oxygen fugacity of ore-forming fluid increased in Donggushan,while the oxygen fugacity of ore-forming fluid decreased in Ruanjiawan,Guilinzheng and Gaojiabang.The scheelites from the Donggushan,Ruanjiawan,Guilinzheng and Gaojiabang deposits show enrichment in LREEs and HFSE,with Nb/La ratios ranging from 1.217 to 52.455,indicating that the four tungsten deposits are enriched in the volatile fluorine.A plot of(La/Lu)N versus Mo/δEu can be used to distinguish quartz vein type,porphyry and skarn tungsten deposits.This study demonstrates that scheelite grains can be used to infer tungsten mineralization and are effective in identifying magmatic types of tungsten deposits in prospective mining sites.

Molybdenite Re-Os,titanite and garnet U-Pb dating of the Magushan skarn Cu-Mo deposit,Xuancheng district,Middle-Lower Yangtze River Metallogenic Belt

The Magushan skarn Cu-Mo deposit is a representative example of the skarn mineralization occurring within the Xuancheng ore district of the Middle-Lower Yangtze River Metallogenic Belt of eastern China.The precise age of an ore deposit is important for understanding the timing of mineralization relative to other geological events in a region and to fully place the formation of a mineral deposit within the geological context of other processes that occur within the study area.Here,we present new molybdenite Re-Os and titanite and andradite garnet U-Pb ages for the Magushan deposit and use these data to outline possible approaches for identifying genetic relationships in geologically complex areas.The spatial and paragenetic relationships between the intrusions,alteration,and mineralization within the study area indicates that the formation of the Magushan deposit is genetically associated with the porphyritic granodiorite.However,this is not always the case,as some areas contain complexly zoned plutons with multiple phases of intrusion or mineralization may be distal from or may not have any clear spatial relationship to a pluton.This means that it may not be possible to determine whether the mineralization formed as a result of single or multiple magmatic/hydrothermal events.As such,the approaches presented in this study provide an approach that allows the identification of any geochronological relationships between mineralization and intrusive events in areas more complex than the study area.Previously published zircon U-Pb data for the mineralization-related porphyritic granodiorite in this area yielded an age of 134.2±1.2 Ma(MSWD=1.4)whereas the Re-Os dating of molybdenite from the study area yielded an isochron age of 137.7±2.5 Ma(MSWD=0.43).The timing of the mineralizing event in the study area was further examined by the dating of magmatic accessory titanite and skarn-related andradite garnet,yielding U-Pb ages of 136.3±2.5 Ma(MSWD=3.2)and 135.9±2.7 Ma(MSWD=2.5),respectively.The dating of magmatic and hydrothermal activity within the Magushan area yields ages around 136 Ma,strongly suggesting that the mineralization in this area formed as a result of the emplacement of the intrusion.The dates presented in this study also provide the first indication of the timing of mineralization within the Xuancheng district.providing evidence of a close genetic relationship between the formation of the mineralization within the Xuancheng district and the Early Cretaceous magmatism that occurred in this area.This in turn suggests that other Early Cretaceous intrusive rocks within this region are likely to be associated with mineralization and should be considered highly prospective for future mineral exploration.This study also indicates that the dating of garnet and titanite can also provide reliable geochronological data and evidence of the timing of mineralization and magmatism,respectively,in areas lacking other dateable minerals(e.g.,molybdenite)or where the relationship between mineralization and magmatism is unclear,for example in areas with multiple stages of magmatism,with complexly zoned plutons,and with distal skarn mineralization.

Research and Application of Micromotional Exploration in the Middle-Lower Yangtze Metallogenic Belt of China

Micromotion is the daily tiny vibration of the earth’s surface. Micromotional exploration can use the surface wave information of micro motion to study the shallow structure of underground media. In this study, we collected microtremor data at 68 stations in the Middle-Lower Yangtze Metallogenic Belt (MLYMB) and determined the resonant frequency and obtained the distribution of sedimentary thickness in this area by using H/V spectral ratio. According to the results of H/V, the sedimentary layer in the basin is thick, and the predominant frequency of the basin is 0.05 - 0.1 Hz. There are no obvious lateral changes in the impedance interface between bedrock and sedimentary layer in this area. The basement of Tongling, Anqing and Luzhou mining areas and their adjacent areas is Kongling-Dongling type basement, which is composed of a set of metamorphic core complex. The predominant frequency is 0.05 - 0.1 Hz. The sedimentary thickness gradually thinned from 3800 m in the west to 2100 m in the East. Moreover, this article used SPAC (spatial autocorrelation) method to obtain the S-wave velocity structure of the mining area near Luzong. The SPAC method reveals that the depth of the interface between the loose sediments and the volcanic rocks is about 600 m in the study area near the Luzhou mining area in the Middle-Lower Yangtze Metallogenic Belt, and the average depth of the interface between the volcanic rock section and the intrusive complex section is about 1000 m. The thickness of the intrusive rock is more than 2500 m. Tourmaline is developed in the interior of the intrusive rock, which may have better exploration value.

Intensification of the East Asian Monsoon in Southern China at about300-400 kaBP Inferred from Eolian Deposits in the Middle-lower Reaches of the Yangtze River

In the East Asian monsoon region, eolian deposits widely distributed in the middle-lower reaches of the Yantgze River are among the best materials available for studies on Quaternary climate change in the subtropical zone of Southern China. Typical eolian deposits in this region include upper Xiashu Loess （XL） and underlying Vermiculated Red Soil （VRS） layers. In this paper, chronological and paleoclimatic studies are conducted on an eolian deposit sequence near Jiujiang （J J） city in northern Jiangxi province. A magnetostratigraphic study, combined with optically stimulated luminescence （OSL） dating, is conducted on the JJ section and provides further evidence that eolian deposits in the middle-lower reaches of the Yangtze River have been formed since the late Early Pleistocene, and that the boundary age between the XL and VRS layers is about 300-400 kaBP. In grain-size records of the JJ section, the median grain-size and content of the 〉30μn size fraction increase sharply after 300-400 kaBP, representing an East Asian winter monsoon intensification event. Further pollen analysis reveals differing pollen assemblages before and after 300-400 kaBP： there is an evident increase in plants adapted to grow in a warm humid environment after 300-400 kaBP, implying an increase in precipitation caused by intensification of the East Asian summer monsoon. Global ice volume and uplift of the Tibet Plateau （TP） are regarded as crucial factors influencing variations of the East Asian monsoon on a long-term scale. The deep-sea JlSO record, which reflects variations in global ice volume, shows no obvious change after 300-400 kaBP. Moreover, the influence of global ice volume changes on the East Asian summer and winter monsoons is inverse; the global ice volume increase （decrease） implies a strengthened （weakened） winter monsoon and weakened （strengthened） summer monsoon. We therefore interpret the coupled intensifications of the East Asian summer and winter monsoons at about 300-400 kaBP to the uplift of the TP in the Middle Pleistocene. This climate event is also documented in eolian deposits from the southern margin of the Chinese Loess Plateau （CLP） and from the desert-loess transitional belt. However, it is not recorded in the loess-paleosol sequences from the central part of the CLP, thereby indicating differing climate responses to TP uplift in different regions, which requires further study.

Large-scale Migration of Fluids toward Foreland Basins during Collisional Orogeny: Evidence from Triassic Anhydrock Sequences and Regional Alteration in the Middle-Lower Yangtze Area

The middle-lower Yangtze area underwent a series of complex tectonic evolution, such as Hercynian extensional rifting, Indosinian foreland basining, and Yanshanian transpression-transtension, resulting in a large distinctive Cu-Fe-Au metallogenic belt. In the tectonic evolution, large-scale migration and convergence of fluids toward foreland basins induced during the collisional orogeny of the Yangtze and North China continental blocks were of vital importance for the formation of the metallogenic belt. Through geological surveys of the middle-lower Yangtze area, three lines of evidence of large-scale fluid migration are proposed: (1) The extensive dolomitic and silicic alteration penetrating Cambrian-Triassic strata generally occurs in a region sandwiched between the metallogenic belt along the Yangtze River and the Dabie orogenic belt, and in the alteration domain alternately strong and weak alteration zones extend in a NW direction and are controlled by the fault system of the Dabie orogenic belt; it might record the locus of the activities of long-distance migrating fluids. (2) The textures and structures of very thick Middle-Lower Triassic anhydrock sequences in restricted basins along the river reveal the important contribution of the convergence of regional hot brine in restricted basins and the chemical deposition or their formation. (3) Early-Middle Triassic syndepositional iron carbonate sequences and Fe-Cu-Pb-Zn massive sulfide deposits alternate with anhydrock sequences or are separated from the latter, but all of them occur in the same stratigraphic horizon and are intimately associated with each other, being the product of syndeposition of high-salinity hot brine. According to the geological surveys, combined with previous data, the authors propose a conceptual model of fluid migration-convergence and mineralization during the Dabie collisional orogeny.

Geologic,Fluid Inclusion and Stable Isotope Constraints on Mechanisms of Ore Deposition at the Datuanshan Copper Deposit,Middle-Lower Yangtze Valley,Eastern China

The Datuanshan deposit is one of the largest and most representative stratabound copper deposits in the Tongling area,the largest ore district in the Middle-Lower Yangtze River metallogenic belt.The location of the orebodies is controlled by the interlayer-slipping faults between the Triassic and Permian strata,and all the orebodies are distributed in stratiform shape around the Mesozoic quartz monzodiorite dikes.Based on field evidence and petrographic observations,four mineralization stages in the Datuanshan deposit have been identified：the skarn,early quartz-sulfide,late quartzsulfide and carbonate stages.Chalcopytite is the main copper mineral and mainly formed at the late quartz-sulfide stage.Fluid inclusions at different stages were studied for petrography,microthermometry,laser Raman spectrometry and stable isotopes.Four types of fluid inclusions,including three-phase fluid inclusions（type 1）,liquid-rich fluid inclusions（type 2）,vapour-rich fluid inclusions（type 3） and pure vapour fluid inclusions（type 4）,were observed.The minerals from the skarn,early and late quartz-sulfide stages contain all fluid inclusion types,but only type 2 fluid inclusions were observed at the carbonate stage.Petrographic observations suggest that most of the inclusions studied in this paper are likely primary.The coexistence of different types of fluid inclusions with contrasting homogenization characteristics（to the liquid and vapour phase,respectively） and similar homogenization temperatures（the modes are 440-480℃,380-400℃ and 280-320℃ for the skarn,early and late quartz-sulfide stages,respectively） in the first three stages,strongly suggests that three episodes of fluid boiling occurred during these stages,which is supported by the hydrogen isotope data.Laser Raman spectra identified CH_4 at the skarn and early quartz-sulfide stages.Combined with other geological features,the early ore-forming fluids were inferred to be under a relatively reduced environment.The CO_2 component has been identified at the late quartz-sulfide and carbonate stages,indicating that the late ore-forming fluids were under a relatively oxidized environment,probably as a result of inflow of and mixing with meteoric water.In addition,microthermometric results of fluid inclusions and H-O isotope data mdicate that the ore forming fluids were dominated by magmatic water in the early stages（skarn and early quartz-sulfide stages） and mixed with meteoric water in the late stages（late quartz-sulfide and carbonate stages）.The evidence listed above suggests that the chalcopyrite deposition in the Datuanshan deposit probably resulted from the combination of multiepisode fluid boiling and mixing of magmatic and meteoric water.

Discovery of Lorandite TlAsS_2 at the Distal Au-Tl Deposit in a Skarn system,Fengshan Area,Middle-Lower Yangtze River,Eastern China

Thallium has been used geochemical exploration of gold deposits. However, as an indicator element in searching for hydrothermal the T1 minerals and mineralization are rare in nature. Lorandite T1AsS2, a relatively uncommon mineral, has been dominantly discovered in some Carlin gold deposits, and minor Sb- Hg, U and Pb-Zn-Ag deposits.

Flood and Waterlogging Disaster Damage Evaluation in Middle-Lower Yangtze River by 3S technology

The evaluation method, model and process for the flood and waterlogging disaster condition by GIS,RS and GPS technology and the method for setting up disaster condition database, dyke database and historical disaster damage database are presented. An index of flood damage degree(FDD) used to evaluate the relative degree of disaster loss and divide flood and waterlogging area is suggested. The value of flood damage degree can be calculated as follows :taking the various disaster losses of sample area in a base year as standard value and computing the ratios of various disaster loss values in different areas and years to the standard flood disaster loss values, then summing up the weighted ratios. The computed results are the value of flood damage degree in the every year. The macroscopic flood disaster distribution can be evaluated by the values of flood loss degree.

Tectonodynamic Adjustment of Crustal Materials in the Middle-Lower Reaches of the Yangtze River

Under the tectonodynamic process, crustal materials tend to experience two modes of adjustment: (1) structural (physical) adjustment, manifested by folding, faulting, uplifting, downwarping, etc.: (2) compositional adjustment, represented by element migration, concentration and dispersion, crystalline and dynamic differentiation of crystals, metamorphism, etc. (Yang Kaiqing. 1986; Yang Kaiqing et al., 1986). The dynamic adjustment of crustal materials in the middle-lower reaches of the Yangtze mainly occurred in the Mesozoic under the conditions of intense collision between the North China (Dabie) massif and the Yangtze massif. The structural adjustment refers to various types of deformation within the two massifs and the intensive shortening of the stratigraphic coyer of the Yangtze massif, whereas the compositional adjustment implies the structural remelting of the basement and the ore. and rock- forming processes in the two massifs.

Geological and Geochemical Constraints on the Newly Discovered Yangchongli Gold Deposit in Tongling Region, Lower Yangtze Metallogenic Belt

The newly discovered Yangchongli gold deposit is a unique independent gold deposit in the Tongling ore-cluster region controlled by the tectonic alteration firstly discovered in the Lower Yangtze Metallogenic Belt （LYMB）. The host magmatic rocks mainly consist of monzodiorite and K-feldspar granite. The LA-ICP-MS U-Pb zircons dating yielded weighted mean 206pb/23SU ages of 140.7 ± 1.8 Ma and 126.4 ±1.2 Ma for the monzodiorite and K-feldspar granite, respectively. Monzodiorites are enriched in Sr, Ba, Rb, and depleted in Y, Yb with high Sr/Y and La/Yb ratios, similar to the geochemical features of adakite, considered as products of differentiation of mafic magmas originating from lithospheric mantle melt/fluids caused by metasomatism during paleo-Pacific Plate subduction in the Mesozic. In contrast, the compositions of K-feldspar granites are A-type granites, indicating an extensional tectonic background. Gold ores hosted in the fracture zone occurred as quartz vein within cataclastic rock. Sulfur and lead isotopes from pyrites show crust-mantle mixing characteristics. Metal components from strata also took part in the gold mineralization, and resulted from two episodes of magmatism that were probably related to tectonic transition from a compressive to an extensional setting between 140-126 Ma, which led to the Mesozoic large-scale polymetallic mineralization events in eastern China.

Multistage Deformation in the Northeastern Segment of the Jiangshao Fault (Suture) Belt: Constraints for the Relationship between the Yangtze Plate and the Cathaysia Old Land

Multistage deformation events have occurred in the northeastern Jiangshao Fault （Suture） Belt. The earliest two are ductile deformation events. The first is the ca. 820 Ma top-to-the-northwest ductile thrusting, which directly resulted from the collision between the Cathaysia Old Land and the Chencai Arc （？） during the Late Neoproterozoic, and the Jiangnan Orogenic Belt that formed as the ocean closed between the Yangtze Plate and the jointed Cathaysia Old Land and the Chencai Arc due to continuous compression. The second is the ductile left-lateral strike-slipping that occurred in the latest Early Paleozoic. Since the Jinning period, all deformation events represent the reactivation or inversion of intraplate structures due to the collisions between the North China and Yangtze plates during the Triassic and between the Philippine Sea and Eurasian plates during the Cenozoic. In the Triassic, brittle right-lateral strike-slipping and subsequent top-to-the south thrusting occurred along the whole northeastern Jiangshao Fault Zone because of the collision between the North China and Yangtze plates. In the Late Mesozoic, regional extension took place across southeastern China. In the Cenozoic, the collision between the Philippine Sea and Eurasian plates resulted in brittle thrusts along the whole Jiangnan Old land in the Miocene. The Jiangshao Fault Belt is a weak zone in the crust with long history, and its reactivation is one of important characteristics of the deformation in South China; however, late-stage deformation events did not occur beyond the Jiangnan Old Land and most of them are parallel to the strike of the Old Land, which is similar to the Cenozoic deformation in Central Asia. In addition, the Jiangnan old Land is not a collisional boundary between the Yangtze Plate and Cathaysia Old Land in the Triassic.

Mineralization,Geochemistry and Zircon U-Pb Ages of the Paodaoling Porphyry Gold Deposit in the Guichi Region,Lower Yangtze Metallogenic Belt,Eastern China

The newly discovered Paodaoling porphyry Au deposit from the Guichi region, Lower Yangtze River Metallogenic Belt （LYRB）, contains 〉35 tons of Au at an average grade of -1.7 g/t. It is a porphyry ＇Au-only＇ deposit, as revealed by current exploration in the depths, mostly above -400 m, which is quite uncommon among coeval porphyry mineralization along the LYRB. Additionally, there are also Cu-Au bearing porphyries and barren alkaline granitoids in the Paodaoling district. Zircon LA-ICP-MS U-Pb dating of the Cu-Au-bearing porphyries yield an age of 141-140 Ma, falling within the main magmatic stage of the LYRB, whereas the barren granites give an age of 125-120 Ma, coeval with the regional A- type granites. The Cu-Au-bearing porphyries are LILE-, LREE-enriched and HFSE-depleted, typical of arc magmatic affinities. The barren granites are HFSE-enriched, with lower LREE/HREE ratios and pronounced negative Eu anomalies. The Cu-Au-bearing porphyries in the Paodaoling district have high oxygen fugacities and high water content. Pyrite sulfur isotopes of the Paodaoling gold deposit indicate a magmatic-sedimentary mixed source for the ore-forming fluids. Based on the alteration and poly-metal zonation of the deepest exploration drill hole from the Paodaoling Au deposit, we propose that Cu ore bodies could lie at depth beneath the current Au ore bodies. The magmatism and associated Cu-Au mineralization of the Paodaoling district are likely to have formed in a subduction setting, during slab rollback of the paleo-Pacific plate.

Basement Characteristics and Crustal Evolution of the Copper-Gold Metallogenic Belt in the Middle and Lower Reaches of the Yangtze River:Some Isotope Constraints

Studies of the Pb, Sr and Nd isotopic composition of Mesozoic intrusive rocks indicate that the basement of the copper-gold metallogenic belt of the middle and lower reaches of the Yangtze River has “two-layer structure” and partly has “multi-layered structure”, and is inhomogeneous and shows the distinct feature of E-W provincialism. The calculated model lead ages (t1) are mostly greater than 2600 Ma, and the model neodymium ages (TDM) vary from 953 to 2276 Ma and concentrate in two time intervals: 1800–2000 Ma and 1200–1600 Ma. It is concluded that the basement of the MBYR is composed of the Late Archaeozoic to Middle Proterozoic metamorphic series and that the crust was initiated in the Archaean and continued to grow in the Early and Middle Proterozoic, and the proportion of new crust formed by mantle differentiation during the Late Proterozoic is low.

Three-dimensional P-wave Velocity Structure Modelling of the Middle and Lower Reaches of the Yangtze River Metallogenic Belt: Crustal Architecture and Metallogenic Implications

In this study,we compiled and analyzed 69310 P-wave travel-time data from 6639 earthquake events.These events(M≥2.0)occurred from 1980 s to June 2019 and were recorded at 319 seismic stations(Chinese Earthquake Networks Center)in the study area.We adopted the double-difference seismic tomographic method(tomo DD)to invert the 3-D P-wave velocity structure and constrain the crust-upper mantle architecture of the Middle and Lower Reaches of the Yangtze River Metallogenic Belt(MLYB).A 1-D initial model extracted from wide-angle seismic profiles was used in the seismic tomography,which greatly reduced the inversion residual.Our results indicate that reliable velocity structure of th e uppermost mantle can be obtained when Pn is involved in the tomography.Our results show that:(1)the pattern of the uppermost mantle velocity structure corresponds well with the geological partitioning:a nearly E-W-trending low-velocity zone is present beneath the Dabie Orogen,in contrast to the mainly NE-trending low-velocity anomalies beneath the Jiangnan Orogen.They suggest the presence of thickened lower crust beneath the orogens in the study area.In contrast,the Yangtze and Cathaysia blocks are characterized by relatively high-velocity anomalies;(2)both the ultra-high-pressure(UHP)metamorphic rocks in the Dabie Orogen and the low-pressure metamorphic rocks in the Zhangbaling dome are characterized by high-velocity anomalies.The upper crust in the Dabie Orogen is characterized by a low-velocity belt,sandwiched between two high velocity zones in a horizontal direction,with discontinuous low-velocity layers in the middle crust.The keel of the Dabie Orogen is mainly preserved beneath its northern section.We infer that the lower crustal delamination may have mainly occurred in the southern Dabie Orogen,which caused the mantle upwelling responsible for the formation of the granitic magmas emplaced in the middle crust as the low-velocity layers observed there.Continuous deep-level compression likely squeezed the granitic magma upward to intrude the upper crustal UHP metamorphic rocks,forming the'sandwich'velocity structure there;(3)high-velocity updoming is widespread in the crust-mantle transition zone beneath the MLYB.From the Anqing-Guichi ore field northeastward to the Luzong,Tongling,Ningwu and Ningzhen orefields,high-velocity anomalies in the crust-mantle transition zone increase rapidly in size and are widely distributed.The updoming also exists in the crust-mantle transition zone beneath the Jiurui and Edongnan orefields,but the high-velocity anomalies are mainly stellate distributed.The updoming high-velocity zone beneath the MLYB generally extends from the crust-mantle transition zone to the middle crust,different from the velocity structure in the upper crust.The upper crust beneath the Early Cretaceous extension-related Luzong and Ningwu volcanic basins is characterized by high velocity zones,in contrast to the low velocity anomalies beneath the Late Jurassic to Early Cretaceous compression-related Tongling ore field.The MLYB may have undergone a compressive-to-extensional transition during the Yanshanian(Jurassic-Cretaceous)period,during which extensive magmatism occurred.The near mantle-crustal boundary updoming was likely caused by asthenospheric underplating at the base of the lower crust.The magmas may have ascended through major crustal faults,undergoing AFC(assimilation and fractional crystallization)processes,became emplaced in the fault-bounded basins or Paleozoic sequences,eventually forming the many Cu-Fe polymetallic deposits there.

Spatio-temporal evolution and factor explanatory power analysis of urban resilience in the Yangtze River Economic Belt

Urban resilience assesses a city’s ability to withstand unknown risks.Scholars are not comprehensive in assessing urban resilience,and they lack consideration of population resilience.This study investigated 110 prefecturelevel cities in the Yangtze River Economic Belt(YREB)as study areas.We calculated the YREB’s level of urban resilience based on the aspects of“economy-society-population-ecology-infrastructure”,which ensured that the comprehensive evaluation of urban resilience is complete and sufficient.The spatio-temporal evolution of urban resilience was analyzed using exploratory spatial data.Geodetectors were used to investigate the impact of several indicators,focusing on economic,social,population,ecological,and infrastructure factors,on urban resilience.The results showed that the urban resilience of the YREB has maintained a slow upward trend from 2005 to 2018,and the average urban resilience of the YREB has risen from 0.2442 to 0.2560.The resilience gap between cities in the study region increased initially and then decreased.The dominant factor in the spatial differentiation of urban resilience was the economic factors,followed by the population factors.Urban resilience has been clarified and an evaluation index system is constructed,which can provide an effective reference for the evaluation of urban resilience among countries around the world.Based on this,factors that optimize urban resilience are configured,and the regional and national sustainable development can be promoted.