Ore-forming material of Dachang tin deposit in Guangxi, China:Lead isotope evidence

For revealing the ore sources of the Dachang tin?polymetallic ore deposit, the lead isotopes were analyzed systematically by using the single minerals of sulphides, including pyrite, pyrrhotite, sphalerite, and galena. Then, the mineral sources and their characteristics were discussed based on the classical lead isotope discriminating model. The results show that the lead isotope ratios of206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb range from 17.478 to 18.638, 15.440 to 15.858, and 37.556 to 39.501, respectively. According to Zartman lead model, the ore lead contains the upper crust composition; however, the granite does not provide all ore leads, and other material sources exist. Obviously, the ore deposit belongs to the result of the combined effect of crust?mantle. The source rocks are characterized by a certain degree of similarity with the island arc material. Moreover, its distant origin in the upper and lower crusts may be related to the subduction island arc material or oceanic crust. The mantle-derived material may have a certain status in the source region. Meanwhile, based on the lead isotope three-dimensional topology projection vectors, the ore leads are concentrated in zoneA, which indicates the characteristics of Yangtze lead isotope province and a possible genetic relationship with Yangtze block.

Geochemistry of intrusive rock in Dachang tin-polymetallic ore field, Guangxi, China: Implications for petrogenesis and geodynamics

The major element, trace element and rare earth element（REE） of the intrusion rock from the Dachang ore field in Guangxi, China, were analyzed. The results show that the phenocryst（about 15%） and matrix（about 85%） mainly consist of quartz, K-feldspar and plagioclase. The rock is composed of low content of Si and high content of Al2O3, low contents of Ca, Fe2O3, Na, TiO2, etc. The intrusion rock has the medium alkali content, attributing to K-rich type rock; and contains medium to low REE contents, of which light rare earth elements（LREEs） and heavy rare earth elements（HREEs） are highly fractionated, showing a weak negative Ce anomaly and a negative Eu anomaly. These rocks are enriched in LREE, and the large ion lithophytes elements（LILE） are rich in Rb, Sr, and U; the high-field-strength elements（Nb, Th, etc） are relatively depleted. The REE chondrite-normalized patterns are consistent with the overall, roughly indicating their similar characteristics, sources and evolution. The intrusion rock mainly formed during the collisional and within-plate periods.

Dating of the Dachang Superlarge Tin-polymetallic Deposit in Guangxi and Its Implication for the Genesis of the No. 100 Orebody

The Dachang superlarge Sn-polymetal deposit in Guangxi, China, is one of the largest tin deposit all over the world. However, this deposit has long been in debate as to its origin. One of the opinions is that the Dachang deposit was formed by replacement of hydrothermal solution originating from Yanshanian granites, and the other is that this deposit was formed by submarine exhalation in the Devonian. This paper presents some new isotopic geochronology data obtained with the 40Ar-39Ar method for quartz and sanidine from massive ore in the No. 91 and No. 100 orebodies. Analytic results show that the No. 91 orebody was formed at 94.52±0.33 Ma (the plateau age obtained with the 40Ar-39Ar method for quartz) or 91.4±2.9 Ma (the plateau age obtained with the 40Ar-39Ar method for feldspar), while the No. 100 orebody was formed at 94.56±0.45 Ma (the plateau age obtained with the 40Ar-39Ar method for quartz), suggesting that both the No. 91 and the No. 100 orebodies were formed at the Late Yanshanian instead of the Devonian. The No. 100 orebody might be formed by filling of ore materials into caves in Devonian reef limestone. Because the ore-bearing solution released its pressure and lowered its temperature suddenly in a cave environment, ore minerals were formed concentratedly while water and other materials such as CO2 evaporated quickly, resulting less alteration of host rocks.

Geological features and S isotope composition of tin deposit in Dachang ore district in Guangxi

The geological investigation of the Dachang ore field was carried out in detail, and the geological characteristics of the deposits, consisting of the Tongkeng and Dafulou deposits, were observed and researched systematically. It suggests that the mineralization types of Changpo ore are composed of cracking vein, thin vein, bedded vein and thin vein-net vein disseminated types. The cracking vein ore is usually lens-shaped in the vertical direction. The thin vein ore is always characterized by a stable trend and tendency. The bedded ore always occurs along the strata in the way of filling and metasomatism in the fracture system. In terms of Bali-longtoushan ore, it is characterized by complicated mineral components and a variety of minerals. More generally, ore textures consist of the anhedral-subhedral shapes and thin particle, and secondary with the interstitial texture, solid solution separation texture, dissolution texture, corona texture, and crushing texture, yet ore structures include the massive, veinlet, disseminated, banded, miarolitic, biological residual and brecciated structure. In addition, the sulfur isotopes of the metal sulfide were analyzed. The results show that the δ34S values of Tongkeng ore range from-0.30% to 1.38% with more dispersed characteristics, yet in terms of Dafulou ore, the δ34S values are from-0.15% to 0.22% which are characterized by more focused. This indicates that the sulfur isotope composition has large difference between the different deposits. The sulfur isotope values of the Dafulou ore are concentrated relatively, yet are dispersed for the Tongkeng ore. Likewise, there are also divergences of sulfur isotopes for the different minerals. The sulfur isotope values of pyrrhotine are dispersed, yet are homogeneous for pyrite. In short, the divergence of the sulfur isotope is reflected in both the different deposits and minerals, all of these may account for the difference of sulfur sources.

Fluid inclusion and mineralization of Dafulou tin deposit in Dachang metal district, Guangxi, south China

Based on the study of the petrology, mineralogy, structural geology and fluid inclusion of the Dafulou ore deposit in the Dachang ore field, the ore deposit geology and ore-forming fluids were analyzed. It shows that there are five main hydrothermal alteration types in the Dafulou ore district, namely the silicification, carbonate, sericite, pyrite and pyrrhotite. The mineralization types are composed of the stratiform type, interlayer type and stockwork type. The ore textures present as metasomatic texture, euhedral-subhedral granular texture and solid solution texture. The ore structure consists of massive structure, dissemination structure, fine veined structure, stockwork structure and brecciated structure. Four ore types are recognized, namely the disseminated ore, dense massive ore, veinlet ore and brecciated ore. Six types of fluid inclusions are determined, i.e. the single-phase gaseous fluid inclusions, single-phase salt solution fluid inclusions, two-phase vapour-rich fluid inclusions, two-phase liquid-rich fluid inclusions, three-phase CO2-rich fluid inclusions and solid（s）-bearing fluid inclusions, all of which form in three dominant temperature scopes, 120-150, 230-270, 350-460 °C. But, the majority of them form in the high temperature environment （350-460 °C）. The tectonism plays an important role in the mineralization, which usually controls the scale, occurrence and shape of the Sn orebody. There are four types of hydrothermal fluid systems, H2O-NaCl-CaCl2, H2O-CaCl2, H2O-NaCl-MgCl2 and H2O-MgCl2. Similar to the other ore deposits in the Dachang ore field, there also exists the multiple source of ore-forming fluids. Overall, the Dafulou ore deposit should be the result of the crust-mantle interaction.

Statistical Analysis of the Hole Primary Halo in Dachang Sn-Zn Polymetallic Mining Area of Guangxi

The complexity and diversity of Ore forming is the commonness, of which the difficulty is the evolutional characteristics of geochemical elements. The metallogetie process can be speculated and get useful and microcosmic message for next exploration. In this paper, the research of cluster analysis and factor analysis of the hole primary halo in Dachang Sn-Zn polymetallic mining area in Guangxi reveal that metallogenic process is very complex and superposed by mineralization . It is considered that the enrichment of Zn, Sn superposed anaphase. By sulphide polymetallic, Au is very independency and that Sb, Pb, Ag and Cu are proximal indicator elements for exploring Zn, Sn in the mine.

Re–Os dating of molybdenite and in-situ Pb isotopes of sulfides from the Lamo Zn–Cu deposit in the Dachang tin-polymetallic ore field, Guangxi, China

The Dachang tin-polymetallic district, Guangxi,China, is one of the largest tin ore fields in the world. Both cassiterite-sulfide and Zn–Cu skarn mineralization are hosted in the Mid-Upper Devonian carbonate-rich sediments adjacent to the underlying Cretaceous Longxianggai granite(91–97 Ma). The Lamo Zn–Cu deposit is a typical skarn deposit in the district and occurs at the contact zone between the Upper Devonian limestone and the granite.The ore minerals mainly consist of sphalerite, arsenopyrite,pyrrhotite, galena, chalcopyrite, and minor molybdenite.However, the age of mineralization and source of the metals are not well constrained. In this study, we use the molybdenite Re–Os dating method and in-situ Pb isotopes of sulfides from the Lamo deposit for the first time in order to directly determine the age of mineralization and the tracing source of metals. Six molybdenite samples yielded a more accurate Re–Os isochron age of 90.0 ± 1.1 Ma(MSWD = 0.72), which is much younger than the reported garnet Sm–Nd isochron age of 95 ± 11 Ma and quartz fluid inclusions Rb–Sr isochron age of 99 ± 6 Ma. This age is also interpreted as the age of Zn–Cu skarn mineralization in the Dachang district. Further, in this study we found that in-situ Pb isotopes of sulfides from the Lamo deposit and feldspars in the district's biotite granite and granitic porphyry dikes have a narrow range and an overlap of Pb isotopic compositions(^(206) Pb/^(204) Pb =18.417–18.594,^(207) Pb/^(204) Pb = 15.641–15.746, and^(208) Pb/^(204) Pb = 38.791–39.073), suggesting that the metals were mainly sourced from Cretaceous granitic magma.

Finite element modeling of pore-fluid flow in the Dachang ore district,Guangxi,China:Implications for hydrothermal mineralization

Convective heat transfer associated with the circulation of porefluid in porous rocks and fractures within the upper crust of the Earth is substantial when the temperature gradient is sufficiently high. In order to understand the process of Snpolymetallic mineralization in the Dachang ore district of Guangxi, a finite element method has been used in this study to simulate both pore-fluid flow and heat transfer in this district. On the basis of related geological, tectonic and geophysical constraints, a computational model was established. It enables a computational simulation and sensitivity analysis to be carried out for investigating ore-forming pore-fluid flow and other key factors that may affect hydrothermal ore genesis in the district. The related simulation results have indicated that： （1） permeable fault zones in the Dacbang ore district can serve as preferential pathways for pore-fluid flow on a regional-scale; and （2） the pore-fluid flow can affect the salinity distribution. This latter factor is part of the reason why Sn-polymetallic mineralization has taken place in this district.

A Geochemical Study of Rare Earth and Trace Elements in Cassiterite from Dachang Sn-Polymetallic Ore Field,Guangxi Province

Rare earth and trace elements are determined for cassiterite from a vein-type orebody , a lens and a sheeted-type orebody in the Dachang Sn-polymetallic ore field ,Guangxi Province .Cassiterite from the vein-type orebody has rare earth and trace dement characteristics similar to that of Dachang biotite granite of Late Yanshan age, showing an inheritable and a genetic relationship. Cassiterites from the kns and sheeted-vein orebody have rare earth and trace element characteristics greatly different from those of the vein-type cassiterite and the granite,showing distinctly higher contents of the ore-forming elements As, Sb,Zn,Ag etc.and a positive Eu anomaly and a negative Ce anomaly.The difference of rare earth and trace element characteristics for cassiterite from two kinds of orebodies reflects the compositional difference of ore-forming solutions. Authors suggest that the kns and sheeted-vein orebody was of nonmagmatic , mixed with underground hot brine origin , and that this kind of hot brine reacted with Devonian and Predevonian older strata and extraced some ore-forming metals from the strata and finaly empbced along the bedding and interbyer fracture zone etc. on its ascending way driven by the Indonisian orogenic movement . The vein-type orebody was formed chiefly by post-magmatic hydrothermal sobtions derived from magma differentiation of the Dachang biotite granite .

Geological characteristics and metallogenic significance of the Devonian intermediate-basic volcanic rocks in the Dachang deposit, Guangxi Zhuang Autonomous Region

Recently discovered intermediate-basic volcanic rocks in the Devonian strata at Dachang, Guangxi Zhuang Autonomous Region are dominated by basalts and andesites. Most of them belong to the calc-alkali and alkali series. Petrology and geochemistry data indicate that the volcanic rocks may be formed in a continental rift environment. The volcanic rocks are in conformable contact with the overlying and underlying wall rocks, with such typical sedimentary structures as laminated and striped ones, and the host rocks of the volcanic rocks contain lots of marine fossils such as tentaculite. Many pieces of evidence indicate that the eruption environment of the volcanic rocks is a sea-facies one. The volcanic rocks are of the LREE-enrichment type, with high ratios of light rare-earth elements to heavy rare-earth elements. In addition, they display moderately negative δEu anomalies and moderately negative δCe anomalies with a higher degree of LREE and HREE fractionation. Through the Q-cluster analysis of the REE samples, it is indicated that the ores have a closer relation with the layered volcanic rocks, and also possess a certain inheritance-consistency relationship with the layered volcanic rocks. The source of ore-forming materials may be related with volcanism. It is proposed that the ore deposit in the study area should be genetically explained as the result of marine volcano-sedimentary exhalation of hot water and late superposition-reworking.

Assessment and Future Scenario Estimation of Climate Carrying Capacity in the Beibu Gulf Urban Agglomeration of Guangxi,China

To enhance urban resilience to climate change in the future,this study quantitatively assesses the climate carrying capacity of the Beibu Gulf Urban Agglomeration(BGUA)in the Guangxi Zhuang Autonomous Region from 2000 to 2020 and in a future projected study from 2021 to 2060.The data used includes real-time data from the National Meteorological Observatory,prediction data from the National Climate Center’s global climate model BCC-CSM2-MR under different Shared Socioeconomic Pathways(SSP2-4.5 and SSP5-8.5),and socio-economic development data.The assessment is conducted using four criteria dimensions:climate natural capacity(CNC),extreme climate event pressure(ECP),urban climate pressure(UCP),and urban coordinated development capacity(UCC).The results indicate that from 2000 to 2020,there was a significant interannual fluctuation in the CNC and ECP in the BGUA.The UCP and the UCC showed an increasing trend,while the overall climate-carrying capacity of the BGUA showed a fluctuating decrease.It is estimated that the climate carrying capacity will exhibit a non-significant decreasing trend from 2021 to 2060,with the capacity in the period from 2021 to 2040 generally higher than that in the period from 2041 to 2060 and the SSP2-4.5 scenario higher than the SSP5-8.5 scenario overall.Currently and in the future,the climate-carrying capacity of the BGUA is primarily influenced by normal climate conditions and extreme events such as strong winds and temperature extremes.With the passage of time,climate instability will increase.Under the planned implementation of China’s carbon peak and carbon neutrality pathway,the rate of increase in the capacity for coordinated urban development is expected to surpass the rate of increase in urban climate pressure.Industrial production and energy consumption are the main drivers of future urban climate pressure growth.

Exploration and Research on the Development of Higher Vocational English Education in Guangxi

With the acceleration of economic development and globalization and the rapid development of China’s foreign economy,the position of English education in higher vocational education has become increasingly prominent.Particularly in the multi-ethnic and multi-cultural areas of Guangxi Zhuang Autonomous Region,higher vocational education undertakes the responsibility of talent export for the construction of the China-ASEAN foreign trade exchange platform.However,the current phenomena and problems existing in higher vocational English education in Guangxi need to be deeply discussed and solved.Therefore,this paper discusses the development ideas of English education mode in Guangxi higher vocational education and studies the feasibility suggestions,in order to provide a reference for the future development of higher vocational English education in Guangxi.

Innovation Transformation and Industry-Education Integration:A Study on the Integration Path of Guangxi Zhuang’s Intangible Cultural Heritage and Master of Arts Education in China

This study focuses on the master of arts education in higher education institutions in Guangxi Zhuang Autonomous Region of China,explores the path of integrating Guangxi Zhuang’s intangible cultural heritage with the teaching of master of arts,and puts forward the teaching mode of“thinking guidance-autonomous judgement-program construction.”A theoretical model of innovative transformation of intangible cultural heritage is also summarized.Through the development of this study,it is expected to further enrich the practical teaching mechanism of master of arts education in Chinese universities and form a master of arts teaching model with strong local cultural characteristics.At the same time,the teaching reform based on the integration of Guangxi Zhuang’s intangible cultural heritage and master of arts education also has strong practical significance for promoting the inheritance and innovation of Chinese intangible cultural heritage,promoting the development of cultural and creative industries,and serving the economic and social development of Guangxi.

The Comparison of Contents of Malondialdehyde and Proline in the Area of Karst Area in Northweastern Guangxi Province

[Objective] To select excellent pioneer species of better ecological and economical comprehensive benefits from the common rock hill plants in Karst area in northwestern Guangxi Province.[Method] Determine the contents of malondialdehyde and proline in leaves of 65 strains of plants by thiobarbituric acid method and sultosalicylic acid method,analyze the relevance of the contents of malondialdehyde and proline by mathematics statistics and analyze the 65 kinds of rock hill plants by clustering [Result] The contents of malondialdehyde and proline are 0.005 2-0.038 1 μmol/g.There are comparably significant differences in the contents of malondialdehyde in different plants;The determination of proline contents in plant＇s leaves are 4.347-374.956 μg/ml.There are also significant differences in proline of different leaves of rock hill plants.The contents of malondialdehyde and proline can be used as a reference point in selecting pioneer plants in Karst area.But when we select the pioneer plants,not only the biological characters of the species themselves should be taken into consideration,but also the differences of Karst area environment,ecological and biological benefits and the reasonable distribution of species.[Conclusion] Pistacia chinensis,Zenia insignis,Acacia confusa,Itoa orientalis and Sophora japonica can be used as the first choices of excellent pioneer plants in Karst area in northwestern area which comparably consists with the real situation of afforestation of rock hills and recovery of plants in Guangxi.

A New Labeonine Fish Species, Parasinilabeo longiventralis, from Eastern Guangxi, China (Teleostei: Cyprinidae)

Parasinilabeo longiventralis, a new species is here described from He jiang basin, a tributary of the Zhujiang River （Pearl River） drainage in Fuchuan County, Guangxi Province, southern China. It can be distinguished from all other congeners by having the following combination of characteristics： maxillary barbels length is 78.3-90.4% of rostral barbels length; pelvic-fin length is 83.7-89.4% of the distance between the ventral-fin origin and to the anal-fin origin; a longitudinal wide black stripe running along the posterior lateral line and irregular brown pigments on the sides of the body.

A new blind loach species,Triplophysa huanjiangensis(Teleostei:Balitoridae),from Guangxi,China

A new blind loach of the genus Triplophysa was collected in 2007 from a cave in Leyi village,located near Chuanshan Town,Huangjiang County in the Guangxi Zhuang Autonomous Region of southern China.The new species,Triplophysa huangjiangensis sp.nov,can be distinguished from its congeners by eyes and scales absent;caudalfin forked;adipose keel present;lips with furrows;distal margin of dorsal-fin truncate,dorsal fin origin much closer to caudal-fin base than snout tip;8-9 branched dorsal-fin rays;6-7 branched pelvic-fin rays;6 branched anal-fin rays;10-11 branched pectoral-fin rays;13-14 branched caudal-fin rays;pectoral-fin length 52.3%-70.7% the distance between pectoral-fin origin to pelvic-fin origin;dorsal-fin origin posterior to vertical line of pelvic-fin origin;outer rostral barbel longer than other two pairs of barbels,with 47.0%-73.8% of lateral head length;anterior nostril with elongate barbel-like tip;and posterior chamber of gas-bladder developed,reaching pelvic-fin origin.

Screening of Drought Stress Indicators and Analysis of Drought Resistance in Cultivated Rice Germplasm Resources in Guangxi

This study aimed to screen drought stress indicators and analyze the drought resistance in 105 cultivated rice germplasm resources in Guangxi Zhuang Autonomous Region under drought stress in the whole growth period based on D value of seven morphological traits including panicle neck thickness,effective panicle number per plant,1 000-grain weight,filled grain number per panicle,total grain number,seed setting rate and yield per plant.According to the results,under drought stress,yield per plant exhibited significant positive correlation with panicle neck thickness and exhibited extremely significant positive correlation with other five morphological traits.Based on the identification and evaluation of comprehensive drought-resistance index D value,seven highly drought-resistant cultivated rice varieties were screened,accounting for 6.67％.Upland rice germplasm resources in Guangxi Zhuang Autonomous Region possess strong drought-resistance capacity,which could be used to screen highly drought-resistant rice germplasm materials.This study provided material basis and theoretical reference for breeding drought resistant rice cultivars in Guangxi Zhuang Autonomous Region.

Analysis on causes of tropical cyclones and their disasters affecting on Guangxi coast based on historical data

The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casualties in the coastal region every year. By counting and analyzing the tropical cyclones affecting Guangxi coast from 1950 to 2012, we find that the annual number of tropical cyclones changes significantly, and the maximum value can be up to 9, whereas the minimum value is 0 in some year. The regularity of seasonal distribution of tropical cyclones is obvious, and the peak period is in July, August and September every year, followed by June and October. Most of tropical cyclones come from the east of Philippines. After entering the South China Sea and passing through Hainan province and Leizhou Peninsula, they landed on Guangxi coast once again and caused the mean of peak surge reaching 111.2 cm, which is 2.6 times of non-landing typhoon. The formation of storm surge disaster is directly related to the severe typhoon weather systems, diurnal spring tide and discharge of river flood. Severe typhoons generate huge waves and rainfall, which lead to the rise of water level at the estuary, and would result in significant increasing water when stacking up with the storm surge, and cause huge tidal disaster.

Provincial Comparative Advantages of Watermelon Production in Guangxi Zhuang Autonomous Region

[Objective]This study aimed to clarify the spatial patterns of comparative advantage of watermelon production in Guangxi Zhuang Autonomous Region, to pro-vide theoretical basis for the development of watermelon industry in China. [Method] Based on the agricultural statistics data of Guangxi and al over China, yield com-parative advantage （YCA） index, efficiency comparative advantage （ECA） index, scale comparative advantage （SCA） index, concentration ratio comparative advantage （CRCA） index, comprehensive comparative advantage （CCA） index, ratio of yield per unit area （RYPA） index and sowing area ratio （SAR） index were established and calculated to determine the watermelon production comparative advantages in 31 provinces （cities） in China. Spacial patterns of the comparative advantages were produced by using GIS software. [Result] Nine provinces Shandong, Henan, Anhui, Hebei, Hubei, Jiangsu, Hunan, Zhejiang and Guangxi were the dominant regions in watermelon production al over the country. The Central and Eastern China showed the integrated comparative advantage in watermelon production, while the Southern, Northeastern, Northern and Northwestern China can be considered as the potential places for watermelon production in future. Southwest China gave more priority to watermelon production, so the comparative advantages kept increasing here. [Con-clusion] Based on this study, watermelon production should be a prior consideration among the agricultural products in Guangxi. Related measures should be developed to optimize the regional distribution of watermelon in Guangxi and China to promote healthy competition in watermelon production.

Distribution of Oxytocin Hypothamic-Picuitary-Ovary Axis in Guangxi Local Buffalo

To study the association of oxytocin (OT)'s distribution in hypothalamatic,pituitary and ovary,and understand how the OT secrete releasing in hypothalamus,pituitary and ovaries,the paraffin section immunohistochemistry SuperPicTureTM two step method was used to detect the distribution of OT in hypothalamatic-pituitary-ovary axis of five femal Guangxi local buffalo. The test results could provide morphology according to study the OT's synthesis and mechanism of action,and could play reference and directions part in breeding Guangxi local buffalo. The test results display:oxytocin immuno reactive (OT-IR) neuronsw eremainly distributed arcuate nucleus,supraoptic nucleus and paraventricular nucleus,and OT-IR neurons was also found in ventromedial nucleus,ventrolateralis nucleus,suprachiasmaticus nucleus,dorsomedial nucleus,mamillary body,anterior hypothalamic nucleus and so on. The OT immunoactive production was found in pituitary and few OT-IR nerve fibers extended to post pituitary from hypophyseal stalk and medium eminence. In ovaries,OT immunoactive productions were only distributed in germinal epithelium cells,granulosa cells and lutein cells. The OT was first discovered in singulorum link of hypothalamatic-pituitary-ovary axis of Guangxi local buffalo. The OT immunoactive neurons were first discovered in every main nucleus of Guangxi local buffalo hypothalamus,especially distributed in arcuate nucleus,supraoptic nucleus and paraventricular nucleus.