Origin of the Yueguang gold deposit in Xinhua, Hunan Province, South China: insights from fl uid inclusion and hydrogen–oxygen stable isotope analysis

The Yueguang gold deposit is located in Fengjia,Xinhua County,Hunan Province,South China.It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt,west of the Baimashan granitic batholith.In order to discern the characteristics of the ore-formingfluids,the underlying mineralization processes,and establish a foundation for the origin of the Yueguang gold depositfluid inclusion micro-thermometry,as well as quartz hydrogen and oxygen isotope analysis,have been carried out on samples obtained from various stages of mineralization.The hydrothermal miner-alization stages within the Yueguang gold deposit can be categorized into three stages:(i)the barren,pre-ore quartz-pyrite stage(Stage Ⅰ),the quartz-pyrite-gold stage(Stage Ⅱ),and the post-ore quartz-carbonate stage(Stage Ⅲ),with the second stage being the main mineralization stage.Thefluid inclusions identified in samples from the main min-eralization stage can predominantly be described with the NaCl–H_(2)O and CO_(2)–NaCl–H_(2)O systems.These inclusions display homogenization temperatures ranging from 158.8 to 334.9℃,and thefluid salinity ranges from 0.3%to 4.0%(wt.%NaCl equiv.).Laser Raman spectroscopy analysis of individual inclusions further reveals the presence of gas-phases such as CO_(2),CH_(4),and N_(2).Isotopic analysis indicatesδ^(18)Ofluid values ranging from 3.95 to 6.7‰ and δDH_(2)O values ranging from-71.9 to-55.7‰.These results indi-cate that the ore-formingfluid of the Yueguang gold deposit belongs to metamorphic hydrothermalfluids of middle-low temperature and low salinity.In the process of ore formation,gold is transported in the form of Au(HS)2-complexes,with gold deposition being driven byfluid immiscibility.Therefore,the Yueguang gold deposit is categorized as an orogenic gold deposit dominated by metamorphic hydrother-malfluid.It may become a new target for gold exploration in the Baimashan region,central Hunan Province.

Characteristics of Shale Reservoir and Sweet Spot Identification of the Lower Cambrian Niutitang Formation in Northwestern Hunan Province, China

The accumulation and productivity of shale gas are mainly controlled by the characteristics of shale reservoirs;study of these characteristics forms the basis for the shale gas exploitation of the Lower Cambrian Niutitang Formation(Fm),Southern China.In this study,core observation and lithology study were conducted along with X-ray diffraction(XRD)and electronic scanning microscopy(SEM)examinations and liquid nitrogen(N2)adsorption/desorption and CH4 isothermal adsorption experiments for several exploration wells in northwestern Hunan Province,China.The results show that one or two intervals with high-quality source rocks(TOC>2 wt%)were deposited in the deep-shelf facies.The source rocks,which were mainly composed of carbonaceous shales and siliceous shales,had high quartz contents(>40 wt%)and low clay mineral(<30 wt%,mainly illites)and carbonate mineral(<20 wt%)contents.The SEM observations and liquid nitrogen(N2)adsorption/desorption experiments showed that the shale is tight,and nanoscale pores and microscale fractures are well developed.BJH volume(VBJH)of shale ranged from 2.144×10^-3 to 20.07×10^-3 cm^3/g,with an average of 11.752×10^-3 cm3/g.Pores mainly consisted of opened and interconnected mesopores(2–50 nm in diameter)or macropores(>50 nm in diameter).The shale reservoir has strong adsorption capacity for CH4.The Langmuir volume(VL)varied from 1.63 to 7.39 cm^3/g,with an average of 3.95 cm^3/g.The characteristics of shale reservoir are controlled by several factors:(1)A deep muddy continental shelf is the most favorable environment for the development of shale reservoirs,which is controlled by the development of basic materials.(2)The storage capacity of the shale reservoir is positively related to the TOC contents and plastic minerals and negatively related to cement minerals.(3)High maturity or overmaturity leads to the growth of organic pores and microfractures,thereby improving the reservoir storage capacity.It can be deduced that the high percentage of residual gas in Niutitang Fm results from the strong reservoir storage capacity of adsorbed gas.Two layers of sweet spots with strong storage capacity of free gas,and they are characterized by the relatively high TOC contents ranging from 4 wt%to 8 wt%.

Ore-Forming Material Sources of the Shizishan Pb-Zn Deposit in Western Hunan Province,China

Objective The Shizishan Pb-Zn deposit is located in the southeastern margin of the Yangtze Block,and its Pb-Zn orebodies are mainly hosted in the Lower Cambrian Qingxudong Formation limestone.Previous researches have investigated the geological characteristics,geochemistry and fluid inclusions of this deposit.

Study on the Change Character of Double Rice Cold Damage in Hunan and Hubei Province during the Past 50 Years

Based on the meteorological data of representative meteorological stations in Hunan and Hubei from 1961 to 2008 years,the change character of double rice cold damage under the background of climate change were analyzed adopting 30 years glide accumulation method.The analysis showed that the 30 years sliding cumulative days of mild low-temperature during spring sowing in Hunan and Hubei were decreased in the recent 50 years,as well as the 30 years sliding cumulative days of moderate low-temperature in central south Hubei,northern and western Hunan.However,there was an increase in southern Hunan,so was the 30 years sliding cumulative days of severe low-temperature.The 30 years sliding cumulative days of mild low-temperature in May reduced in Hunan and Hubei.Instead,that of moderate low-temperature in May in central south Hubei was on the rise,and it was opposite in northern and southern Hunan,but there was no obvious change in western Hunan.The 30 years sliding cumulative days of severe low-temperature showed a decreasing tendency in May in central south Hubei,northern and western Hunan,and southern Hunan showed a contrary tendency.The 30 years sliding cumulative days of mild cold dew wind in Hunan and Hubei were decreased,that of moderate cold dew wind in central south Hubei,northern and western Hunan had the same tendency,but there was a contrary tendency in southern Hunan.The 30 years sliding cumulative days of severe cold dew wind was decreased in central south Hubei and increased in western Hunan,without cold dew wind in northern and southern Hunan.

Ecological Suitability Evaluation on Agricultural Land in Western Jilin Province Based on Fuzzy Mathematics

[Objective] This study was to evaluate the ecological suitability of agricultural land in western Jilin Province, with the aim to provide basis for the effective application of agricultural resources and the structural adjustment of land use. [Method] The evaluation index system was constructed based on fuzzy mathematic method according to the principles of systematic, dominant, effectiveness and feasibility; based on law of tolerance, reasonable evaluation criteria were determined according to the ecological amplitude of crops; based on GIS processing, the initial data completed the mathematical operation by using the VBA program in Excel. [Result] The area of agricultural land grade I was 5 512 km2, grade II of 25 985 km2, grade Ill of 7 907 km2, and area of land not suitable for agriculture was 6 312 km2. According to the evaluation results, the key areas for land use adjustment were Zhenlai County, Da＇an County, Tongyu County and western Changling County. The directions of land use adjustment included improving irrigation and drainage conditions, governing land salinization and conversion of cropland to forest and grassland. [Conclusion] This study provided basis for the effective application of agricultural resources and ecological environment construction in western Jilin Province.

Research on the Agglomeration and Fluctuation Situation of Rice Production in Hunan Province

[Objective] This paper aimed at studying the agglomeration and fluctuation situation of rice production in Hunan Province during the past 10 years.[Method] Data were collected from Hunan Rural Statistical Yearbook（2001-2010）.Taking the concentration index of sown area and production（CDI） and the volatility index（VI） as the main indicators,the agglomeration and fluctuation situation of paddy rice,early-season rice,middle-season rice and single-season late rice,late-season rice,good quality early-season rice,good quality middle-season rice and good quality single-season late rice,good quality late-season rice production in each major rice-producing area of Hunan Province during the past 10 years had been studied.[Result] The orders of concentration index of sown areas and production of paddy rice,early-season rice,middle-season rice and single-season late rice,late-season rice,good quality early-season rice,good quality middle-season rice and good quality single-season late rice,good quality late-season rice in Hunan Province varied,but the orders of volatility index were consistent.The stable areas,relatively stable areas and fluctuant areas in sown areas and production of different major rice-producing areas were defined.[Conclusion] The research had provided basis for optimizing the layout of rice production in Hunan Province,promoting agglomeration and development of rice production and translating the comparative advantages into the competitive advantages.

The Late Tremadocian(Ordovician)Graptolite Kiaerograptus from Central Hunan,China:Taxonomy and Biostratigraphy

Well-preserved graptolites of the genus Kiaerograptus are first reported from the upper Tremadocian Yinchupu Formation in the Nanba section,Yiyang,Hunan Province,South China,including four species,i.e.,Kiaerograptus lauzonensis(Erdtmann,1966),Kiaerograptus stoermeri(Erdtmann,1965),Kiaerograptus cf.supremus?Lindholm,1991,and Kiaerograptus sp.,which are robust in form.Based on these new specimens,the Kiaerograptus biozone is established for the first time in South China,increasing the late Tremadoc graptolite biozones in South China from four to five,in ascending order as follows:the Adelograptus tenellus biozone,the Aorograptus victoriae biozone,the Kiaerograptus biozone,the Sagenograptus murrayi biozone,and the Hunnegraptus copiosus biozone.A review of the occurrence records for robust Kiaerograptus species worldwide reveals that the distribution is restricted to the Aorograptus victoriae biozone and Kiaerograptus biozone in the late Tremadocian.This limited stratigraphical distribution makes Kiaerograptus a valuable taxon for precise biostratigraphical correlation at both the regional and global scales.

Dongbeititan dongi,the First Sauropod Dinosaur from the Lower Cretaceous Jehol Group of Western Liaoning Province,China

We herein describe a partial postcranial skeleton of a sauropod dinosaur recovered from the Lower Cretaceous Jehol Group in the Beipiao area of western Liaoning Province, northeastern China. A suite of features it possesses, including the camellate internal structure of its presacral elements, the existence of pneumatocoels on the proximal ends of the dorsal ribs, and especially the medially deflected proximal portion of the femur, definitively establish the titanosauriform affinities of the specimen. It differs from other titanosauriforms in having a craniocaudally elongate coracoid with a squared cranioventral extreme and a long, smooth, and slightly convex acetabular edge of the pubis. It represents a new taxon, Dongbeititan dongi gen. et sp. nov. Comparative studies suggest that Dongbeititan is a basal titanosauriform, more derived than Euhelopus, Fusuisaurus, and Huanghetitan, but less derived than Gobititan and Jiutaisaurus. Dongbeititan represents the first sauropod dinosaur reported from the Lower Cretaceous Jehol Group of western Liaoning Province.

New Bivalved Arthropods from the Cambrian(Series 3, Drumian Stage) of Western Hunan, South China

We report two new three-dimensionally phosphatized microfossils, Cambrolongispina reticulata gen. et sp. nov. and Cambrolongispina glabra gen. et sp. nov., from the middle Cambrian （Series 3, Drumian Stage） at Wangcun, Yongshun County, western Hunan, South China. They are bivalved arthropods, with thin, pliable, originally chitinous or chitin-calcareous shields （c. 350-517 I1 m long）. The shields are equipped with a pair of antero-dorsal spines. The spines are internally hollow, varying in length from 1/2 of to as long as the shield length in C. reticulata, and uniformly longer than the shield length in C. glabra. The spines of C. reticulata are ornamented with a longitudinal row of conical or blade-shaped denticles along the posterior edge. Cambrolongispina lacks marginal rims, valve lobation and sulci which are diagnostic of the Bradoriida sensu stricto. It also lacks a donblure/duplicature characteristic of phosphatocopids and some bradoriids. It could be related to the Monasteriidae （which may belong to Bradoriida sensu lato）, both characterized by a pair of antero-dorsal spines. Cambrolongispina may have been meiofaunai detritus feeders that lived on or within sediments. The antero-dorsal spines may have been sensory organs to detect nearby predators. The posterior denticles on these spines might have facilitated the sensory function of the spines.

Forest height mapping using inventory and multi-source satellite data over Hunan Province in southern China

Background:Accurate mapping of forest canopy heights at a fine spatial resolution over large geographical areas is challenging.It is essential for the estimation of forest aboveground biomass and the evaluation of forest ecosystems.Yet current regional to national scale forest height maps were mainly produced at coarse-scale.Such maps lack spatial details for decision-making at local scales.Recent advances in remote sensing provide great opportunities to fill this gap.Method:In this study,we evaluated the utility of multi-source satellite data for mapping forest heights over Hunan Province in China.A total of 523 plot data collected from 2017 to 2018 were utilized for calibration and validation of forest height models.Specifically,the relationships between three types of in-situ measured tree heights(maximum-,averaged-,and basal area-weighted-tree heights)and plot-level remote sensing metrics(multispectral,radar,and topo variables from Landsat,Sentinel-1/PALSAR-2,and SRTM)were analyzed.Three types of models(multilinear regression,random forest,and support vector regression)were evaluated.Feature variables were selected by two types of variable selection approaches(stepwise regression and random forest).Model parameters and model performances for different models were tuned and evaluated via a 10-fold cross-validation approach.Then,tuned models were applied to generate wall-to-wall forest height maps for Hunan Province.Results:The best estimation of plot-level tree heights(R2 ranged from 0.47 to 0.52,RMSE ranged from 3.8 to 5.3 m,and rRMSE ranged from 28%to 31%)was achieved using the random forest model.A comparison with existing forest height maps showed similar estimates of mean height,however,the ranges varied under different definitions of forest and types of tree height.Conclusions:Primary results indicate that there are small biases in estimated heights at the province scale.This study provides a framework toward establishing regional to national scale maps of vertical forest structure.

Mineral provinces and matter provenance of the surficial sediments in the western Philippine Sea:implication for modern sedimentation in West Pacific marginal basin

The characteristics and distribution patterns of detrital minerals （0. 063 -0. 125 mm） in marine sediments provide a significant indicator for the identification of the origin of sediment. The detrital mineral composition of 219 surface sediment samples was ana- lysed to identify the distribution of sediments within the western Philippine Sea. The area can be divided into three mineral provinces ： （Ⅰ） province east of the Philippine Trench, the detrital minerals in this province are mainly composed of calcareous or siliceous organisms, with the addition of volcanogenic minerals from an adjacent island arc; （Ⅱ） middle mineral province, clastic minerals including feldspar, quartz and colorless volcanic glass, sourced from seamounts with intermediate-acid volcanic rock, or erupting intermediate-acid volcano; （Ⅲ） province west of the Palau--Kyushu Ridge, the matter provenance within this province is complex; the small quantity of feldspar and quartz may be sourced from seamounts or erupting volcano with intermediate - acid composition, with a component of volcanic scoria sourced from a volcano erupting on the Palau--Kyushu Ridge. it is suggested that, （ 1 ） Biogenic debris of the study area is closely related to water depth, with the amount of biogenic debris controlled by carbonate lysocline. （2） Volcaniclastic matter derived from the adjacent island arc can be entrained by oceanic currents and transported towards the abyssal basin over a short distance. The weathering products of volcanic rocks of the submarine plateau （e. g. , Benham Plateau） and adjacent ridges provide an important source of detrital sedimentation, and the influence scope of them is constrained by the intensity of submarine weathering. （3） Terrigenous sediments from the continent of Asia and the adjacent Philippine island arc have little influence on the sedimentation of this study area, and the felsic mineral component is probably sourced from volcanic seamounts of intermediate-acid composition.

Types of uranium deposits in central Zhuguang Mountains in Hunan Province,South China and their metallogenic regularity and prospecting directions

The central Zhuguang Mountains in Hunan Province is located at the junction of the three provinces,namely Hunan,Jiangxi,and Guangdong,where the famous Lujing uranium ore field lies.The uranium deposits occurring in this area are all granite-related and they can be divided into three types,namely endogranitic ones,perigranitic ones,and contact zone types.The endogranitic uranium deposits are mainly controlled by the structural alteration zones developing within granites,with fragmentation,hematitization,and alkali metasomatism as their main mineralization characteristics.The perigranitic uranium deposits are mainly produced in the carbonaceous,siliceous,and argillaceous composite layers of epimetamorphic rocks and are controlled by fractured zones formed due to interlayer compression.The contact zone type uranium deposits mainly occur in the contact parts between the granites and favorable horizons.They have developed in favorable sections where multiple sets of structures are combined and intersected.The main metallogenic regularities of uranium in the central Zhuguang Mountains are as follows.The basic conditions for the uranium mineralization in this area include the framework consisting of regional deep large faults and their associated multi-set multi-direction favorable metallogenic structures,multi-cycle and multi-stage uranium-rich rock masses,and uranium-rich folded basement.Meanwhile,the uranium deposits in this area are closely related to granites in terms of genesis and space and they are formed in different structural parts subject to the same metallization.Furthermore,based on the summary of the characteristics and regularities of uranium mineralization in this area,the controlling factors of different types of uranium deposits in the area were explored and six metallogenic target areas were predicted.All these will provide references for the exploration of uranium deposits in this area.

SPATIAL DISTRIBUTION AND VARIATION TENDENCY OF DROUGHTS AND FLOODS IN HUNAN PROVINCE DURING THE PAST 36 YEARS

Using the 1970-2005 annual precipitation and evaporation data at 80 gauge stations across Hunan province,this work analyzes the spatial distribution and variation tendency of the local droughts and floods using linear regression,wavelet analysis,abrupt change,clusters,Empirical Orthogonal Function (EOF) and rotated EOF (REOF).Results show that there are four dry areas and three wet areas in Hunan.The whole province exhibits a moistening trend except some small areas in western,eastern and southern Hunan.The most prominent feature of annual precipitation is that the whole province basically displays a consistent variation tendency,as far as the dominant EOF mode is concerned.In addition,the spatial features of the other EOF modes include dry-wet differences,e.g.wet (or dry) in the north versus dry (or wet) in the south,wet (or dry) in the center and dry (or wet) in the surrounding areas.The distribution of the ratios of evaporation to precipitation exhibits both common features as well as spatial differences,which can be classified into four types:South Hunan,North Hunan,Northeast Hunan,and Central Hunan.There is an abrupt change from dry to wet patterns in the early 1990s.Generally,the drought-flood distribution presents variations of three periods.In the late 2000s,Hunan province will be in a period of drought,followed by a period of flood.

Genetic Classification of Pyroclastic Ejecta Based on Physical Volcanology of Possible Large Cauldron in Bombay Volcanic Complex, Western Deccan Trap Province, India

Many Propositions are made about the mechanism of emplacement of volcanoclastic material in the Bombay volcanic complex. The present paper deals exclusively with the physical features of the deposits laid by a complex tectono-magmatic process by making detailed inventory of the different kind of volcanic ejecta exposed in the Bomay Volcanic Complex (BVC), and an attempt has been made to classify the deposits genetically. A subsidenace which was hinted at earlier, may be a possible cauldron in BVC has been proposed, which might be responsible for producing such a varied and complex lithology.

Alkaline Prophyries in the Chenghai-Binchuan Tectono-Magmatic Belt,Western Yunnan Province,SW China

1 Introduction Sanjiang tectonic-magma belt is one of the most potential resources’metallogenic belts in China.Cenozoic alkali-rich porphyry-type gold polymetallic mineralization system is a significant characteristic of thisbelt.Chenghai-Binchuan tectonic belt,located in the western margin of the Yangtze block,is an important part

A New Species of the Genus Tylototriton (Urodela: Salamandridae) from Northeastern Hunan Province, China

We describe a new species from the family Salamandridae from northeastern Hunan Province of China based on morphological and molecular genetic evidences.The new species,Tylototriton liuyangensis,is a member of the T.asperrimus group,and shares a number of similarities with T.wenxianensis and T.broadoridgus.The dorsal surface of the new Tylototriton species is completely black,with nodule-like warts distributed evenly along the lateral margin of dorsal body,and there is no transverse striae between the warts.There are several diagnostic characters of the new species that differ from those of T.wenxianensis and T.broadoridgus as follows：（1）the interorbital space（IOS）is comparatively wide;（2）there is a bony ridge present on the dorsal head surface,running along the upper eyelids;（3）the space between axilla and groin（AGS）is comparatively large,with the mean male AGS approximately equal to 50%of the snout-vent length（SVL）and the mean female AGS being 53%of SVL;and（4）there is a small genital armature on the anterior angle of labial folds present inside the anal fissure of adult males during the breeding season.The result from the molecular phylogenetic analysis of the genus Tylototriton（including the type specimen of the new species）based on the complete DNA sequence of the mitochondrial ND2 gene（1035 bp）indicated that the new species was similar to T.wenxianensis,T.dabienicus,and T.broadoridgus,but formed an independent clade.This result was consistent with the morphological analysis above,supporting that the Liuyang Population represented a distinct species.

The Characteristics of Ore-Controlling Structure in Baoshan Cu-Pb-Zn Polymetallic Deposit,Hunan Province

The Baoshan Cu-Pb-Zn polymetallic deposit is lied in the central Nanling mineralization zone,and belongs to the junction area of the Chenzhou-Linwu fault zone and the Leiyang-Linwu fault zone.It is a significant part of Nanling polymetallic deposit belt.The outcropping stratas consist of upper Devonian Shetianqiao,Xikuangshan Formation,Lower Carboniferous Menggong’ao,Shidengzi,Ceshui,and Zimenqiao Formation.Igneous rocks in the Baoshan ore area mainly comprise granodiorite porphyry.Furthermore,the radio isotopic age ranges from 123 Ma to 183 Ma,belonging to the early to middle Yanshanian.

Late Jurassic-Early Cretaceous Erg Deposits in the Mengyin Basin, Western Shandong Province, China: Inferences about the Wind Regime and Paleogeography

The Late Jurassic-Early Cretaceous Santai Formation, sporadically distributed in western Shandong Province, comprises terrestrial alluvial-eolian successions, which records regional wind patterns and paleogeography in eastern North China. This paper conducts an analysis of eolian stratification, bounding surfaces, facies architecture and paleowind direction of the Santai Formation in the east of the Mengyin Basin, western Shandong Province. Three basic types of eolian stratification are recognized in the Santai Formation, including grainflow strata, wind ripple strata and adhesion strata, and have been grouped into eolian dune and interdune facies associations. The occurrences of reactivation surfaces and superimposition surfaces within eolian dune deposits indicate active compound dunes or draas. The association of adhesion strata with grainflow or windripple strata is the development of a wet eolian system. Cross-strata dip direction indicates different paleowind directions from the lower to the upper part of the Santai paleoerg. The lower part of the paleoerg was characterized by paleowinds blowing from northwest to northeast, whereas the upper part was under the influence of paleowinds consistently towards east to northeast. The identified changes in wind directions possibly suggest wind regime shifts from monsoon circulation to westlies of planetary wind system, which may be related with the collapse of the East China Plateau during the Late Jurassic to Early Cretaceous.

Survey and Countermeasures on Current Status of Farmer Training and Education Informatization in Western Liaoning Province

This study summarized the main achievements of farmers’training and rural informatization construction in the past few years,and explored the needs of rural informatization in western Liaoning Province.The current status of agricultural development in western Liaoning and farmers’needs for education and training and rural education informatization were surveyed.The construction of an education and technical support service platform for scientific and technological farmers in western Liaoning was proposed,aiming to use information technology to train modern professional farmers.Through independent and self-learning education and training methods,it is expected to promote great improvement in the scientific and technological quality and moral level of farmers in western Liaoning and cultivate professional farmers who are educated and understand both agricultural techniques and business management.