The discovery of altered rock-type gold orebodies in southeastern Guizhou (southwestern Jiangnan orogen) highlights the region's significance as a major gold province. However, the timing and the ore-forming processes remain poorly constrained, hindering a comprehensive understanding of gold metallogenic patterns. The Kengtou gold deposit (>15 tons Au) comprises both quartz vein-type and altered rock-type orebodies. Two types of hydrothermal monazite (Mnz1, Mnz2) were identified in this study. Mnz1, associated with pre-ore ankerite (Ank1) and rutile, occurs within unmineralized metamorphic rocks. In contrast, Mnz2 is spatially associated with auriferous sulfides within gold orebodies. Trace-element analyses show that Mnz1 has significantly higher total rare earth element (Sigma REE) concentrations (430,658-583,738 ppm, mean = 565,224 ppm) than Mnz2 (67,779-172,804 ppm, mean = 137,558 ppm), although both exhibit similar hydrothermal-type chondrite-normalized REE distribution patterns. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb dating yielded lower-intercept ages of 443 +/- 16 Ma (Mnz1) and 410 +/- 13 Ma (Mnz2). These ages constrain two distinct hydrothermal episodes: The earlier episode (ca. 443 Ma) represents a pre-ore stage related to Caledonian regional greenschist-facies metamorphism that triggered widespread sericitization, while the later episode (ca. 410 Ma) marks the main gold mineralization stage during late Caledonian extension, where fluid-rock interaction led to the precipitation of gold-bearing pyrite. Overall, we propose that the recognition of two episodes of Caledonian hydrothermal activity has implications for district-scale gold exploration in the southwestern margin of the Jiangnan orogen.

Rational allocation of water resources in agricultural water management is key to ensuring sustainable socioeconomic development. However, regulation for adapting the water rights trading process to water price fluctuations is extremely challenging. As a solution to this problem, an uncertainty modeling approach is proposed in this paper by incorporating two-layer planning, multiobjective nonlinear planning, triangular fuzzy numbers, plausibility constraints, accuracy functions, and linear affiliation functions into a single framework to efficiently use and allocate water resources, aiming to minimize water shortages and maximize water production efficiency and the total system benefits. The approach aims to elucidate the dynamic characteristics of water rights trading, water pricing, and the impacts of economic benefits. Lu County, Sichuan, China, is used as a typical case study. The results show that there are trade-offs and games between water scarcity and water productivity, and their coordination improves the total system benefits by 6.82%. Uncertainty significantly affects the outcome of water rights trading with different objectives; more water promotes water rights trading, with a 6.85% increase in water quantity. In addition, the coupling coordination increases by 4.12% but is accompanied by a higher risk of water scarcity.

Many gold and antimony deposits in the Yunnan-Guizhou-Guangxi region in SW China are characterized with co-occurrence and symbiotic differentiation of Ao and Sb.However,the metallogenic relationship between Au and Sb and the difference between ore-forming processes of Au and Sb need to be further investigated.Fluorite,a common gangue mineral widely occurred in hydrothermal deposits,has been extensively studied to reveal the formation process of ore deposit.The Qinglong antimony deposit and the Nibao gold deposit in the Youjiang basin,with their matching mineralization ages and wallrock alteration characteristics,are selected as ideal objects for investigating the symbiotic differentiation of gold and antimony mineralization.Therefore,in this paper,we have carried out the in situ LA-ICP-MS trace element study of fluorites from the Qinglong antimony deposit and the Nibao gold deposit,in order to reveal the difference between their respective gold and antimony mineralization processes.Mineralogical and cathodoluminescence(CL)studies of fluorites reveal that three different stages of Sb-mineralization related fluorites in the Qinglong antimony deposit have been identified.Specifically,the first-stage fluorites have right-declined REE patterns with LREE-enriched and HREE-depleted characteristics.The second-stage fluorites are characterized by the MREE enrichment.The third-stage precipitated fluorites generally inherited the characteristics of REE distribution patterns of the second-stage fluorites though the third-stage fluorites have relatively low ∑REE contents.In general,the ∑REE values of fluorites are gredually decreased from the first-stage fluorites,second-stage fluorite to the third-stage fluorites.All fluorites have negative Ce anomalies.There are fluorites of two precipitation stages associated with the gold mineralization in the Nibao gold deposit.The first-stage fluorites have right-declined REE patterns,whilst the second-stage fluorites are characterized with MREE-enriched REE patterns.Their REE patterns are generally similar to those of fluorites in the Qinglong antimony deposit.Diagrams of Y/Ho,La/Ho,Tb/Ca,and Tb/La ratios for fluorites at different stages reveal that there are different genetic characteristics between fluorites of the early-ore-stage and those of the late-ore-stage.Especially,the early-ore-stage fluorite is of the dominant hydrothermal fluid filling genesis,while the late-ore-stage fluorite was formed in close association with the water-rock reaction which resulted in the input of a significant portion of host rock components into the late-stage ore-forming fluid,and the gradual increase of pH values and the decrease of total REE contents of the ore-forming fluids from the early-to late-stage.The comprehensive analysis suggested that the antimony mineralization in the Youjiang Basin is associated with the acidic ore-forming fluid which caused the dissolution of carbonate wallrock through the intensive water-rock reaction and thereby resulted in the formation of a significant of fluorite.Moreover,the increase of pH values and the decreaseof temperatures of the evolved ore-forming fluids could be contributed to the extensive precipitation of stibnite in the antimony deposit.Alternatively,the ore-forming fluids of gold deposits are characterized with weakly acidic to neutral nature.They caused the limited decarbonation of carbonate wallrocks and then resulted in the formation of a little fluorite and a large amount of dolomite,which is conducive to the formation of a large amount of Au-bearing pyrite.Based on the statistic analysis of REE data of stibnite and associated ore-related gangue minerals in antimony deposits in the Youjiang Basin,it is believed that the MREE enrichment characteristics for REE patterns of gangue minerals could be resulted from the LREE super-enrichment of a large amount of hydrothermal stibnite of antimony deposits.

To improve the simulation performance of the RegCM4 model in climate simulations over the Yangtze River Basin (YRB), it is essential to determine the optimal cumulus convection and land surface process schemes from the numerous physical parameterization options within RegCM4. In this study, we selected five cumulus convection schemes (Kuo, Grell, Emanuel, Tiedtke, and Kain–Fritsch) and three land surface process schemes (BATS, CLM3.5, and CLM4.5) to configure 72 mixed schemes. Four years of short-term simulations (1990–1993) with a horizontal resolution of 50 km were conducted using ERA-Interim as the initial and boundary conditions for the 72 schemes. The climate simulation performance of all schemes in the YRB was comprehensively evaluated using a multi-criteria scoring approach. The results indicate that among the selected cumulus convection schemes, the Kain–Fritsch scheme, applied to both ocean and land, demonstrates optimal performance in simulating precipitation over the YRB, with spatial correlation coefficients between simulated and observed annual precipitation around 0.3. Compared to the Community Land Models (CLM3.5 and CLM4.5), BATS exhibits superior capabilities in reproducing the temperature features of the region, with spatial correlation coefficients between simulated and observed values typically exceeding 0.99 and standard deviations within 1.25 °C. Under the optimal KF scheme, the simulated soil moisture in the YRB using CLMs is notably drier, ranging from −7.79 to −8.39 kg/m2, compared to that achieved with BATS. The findings provide a localized reference for the parameterization schemes of RegCM4 in the YRB.

Multistage mineralization overprinting is important for the formation of giant hydrothermal gold deposits. The Youjiang basin in SW China has undergone at least three major deformation phases in the Mesozoic, but their relationship with the large-scale gold accumulation in the region remains enigmatic. Here, we study the large Nibao gold deposit (reserve > 70 t Au) in the northern part of the basin, which has both fault-controlled and stratabound orebodies. We identified a pre-ore stage and syn-ore stage including four tectono-hydrothermal (T-H) substages (i.e., T-H stage 1, 2, 3 and 4) for the local mineralization at Nibao. The pre-ore stage is dominated by coarse-grained pyrite coexisting with TiO2 polymorphs in the Middle-Late Permian basaltic rocks. The T-H substage 1 is characterized in that the sedimentary pyrites are brecciated in bedding-parallel faults. Fluorination and silicification occur in the T-H substage 2, which is re-brecciated at the T-H substage 3 forming the highest gold grade ore in high-angle thrust fault. The T-H substage 4 presents as fault reactivation within minor calcite and pyrite deposition. Mineralogy and in-situ trace element analyses reveal that mineral dissolution and reprecipitation (incl. dolomite, auriferous pyrite and TiO2 polymorphs) is ubiquitous during the multistage tectono-hydrothermal process, and the continuous alteration overprinting may have promoted gold accumulation. This replacement process of different generations of auriferous pyrite is also recorded by their inherited sulfur isotopes, giving a narrow delta S-34 (-3.1 to + 2.1 parts per thousand) range. Anatase is the main accessory phase of TiO2 polymorphs, as identified with LA-ICP-MS trace element and laser Raman spectroscopic analyses. Moreover, the anatase can been divided into two types (type-I and II) based on their texture, alteration and chemistry. The type-I anatase commonly occurring in the stratabound ore is characterized by higher Zr (mean 1,730 ppm), V (mean 1,412 ppm), and Cr (mean 110 ppm) contents than type-II that coexists with zoned pyrite in the fault-controlled ore (mean 26 ppm, 187 ppm, and 38 ppm, respectively). Additionally, W (mean 636 ppm) and Mg (10,021 ppm) in type-II are much higher than type-I ones (mean 135 ppm W and 476 Mg). These features show that the sedimentary-stage Zr-V-Cr-rich type-I anatase was dissolved via fluid metasomatism, and reprecipitated as the hydrothermal-stage W-Mg-rich and Zr-poor anatase, with gold gradually enriched. Besides, the anatase phase of TiO2 polymorphs also indicates that the Nibao gold deposit was formed under low pressure-temperature condition. Overall, we propose that the Nibao is a Carlin-type gold deposit, dominated by multistage tectono-hydrothermal events.

The Yangla copper deposit located in the Sanjiang Tethys metallogenic domain is a typical skarn deposit. A series of alterations, with obvious alteration zonation characteristics, are developed from the intrusion to the wallrocks in this deposit. However, previous studies on altered minerals of the Yangla copper deposit mainly focused on the anhydrous skarn stage minerals such as garnet. The lack of systematic mineralogical and compositional studies on the widely developed retrograde alteration stage minerals such as chlorite had restricted the comprehensive understanding of the mineralization process of the Yangla copper deposit. Therefore, in this paper, taking the chlorite in the skarn type mineralization of the Yangla copper deposit as the research object, we have carried out the chemical composition analysis of chlorite by using electron probe microanalysis（EPMA） and LA-ICP-MS in-situ technology and given results below. Two types of chlorite in the Yangla copper deposit have been classified. The early chlorite（Chl-Ⅰ） was intergrown with the andradite, chalcopyrite and other sulfides, and the late chlorite（Chl-Ⅱ） was often intergrown with a large amount of calcite. Both types of chlorite belong to Mg-rich chlorite with trioctahedral structure, indicating that they were formed in a relatively reduced environment. The Tschermark substitution mechanism of Fe 2+ and Mg 2+ is the main substitution mechanism for major elements of two types of chlorites; 2) The calculation results of the chlorite geothermometer range from 140 ℃ to 281 ℃, with an average of 224 ℃. The temperatures of chlorites are gradually decreased from the Chl-Ⅰ to Chl-Ⅱ chlorites, indicating that they were formed in the range of medium and low temperature hydrothermal alteration; 3) From the early mineralization stage（Chl-Ⅰ） to the late mineralization stage（Chl-Ⅱ）, the concentrations of trace elements（Sc, Ti, Ga, V） in chlorites are decreased, which may be related to the gradual decrease of the hydrothermal fluid temperature,indicating that the Ti, Sc, Ga, V-rich chlorite is closely related to mineralization and it can be used as an effective indicator for the relevant mineralization. Therefore, the study of compositions of trace elements in chlorite is of certain significance for the mineral exploration.

It is of great significance to study and analyze the surface water resources and its variation trend in North China for mitigating the water resource shortage, promoting the compressive exploitation of groundwater and realizing the sustainable development of water resources in North China. Taking Minyou Irrigation District in Handan as an example, four analytical methods of Mann-Kendall Trend Test, Cumulative Departure Method, Double Mass Curve and Morlet Wavelet Transform were employed in this paper to analyze and predict the variation trend and the individual contributions of climate change and human activities to runoff variation of the amount of water resources in the irrigation district. The results show that the annual rainfall and annual runoff in the irrigation district have been on a dramatically decreasing trend over the research period. In 1977, a sudden change in the annual runoff occurred and the average contribution rates of climate change and human activities to their variations were 40.55% and 59.46%, respectively. Precipitation and runoff have obvious periodic changes. In the next period, precipitation will show an increasing trend, and runoff will remain stable. The research results can provide a scientific reference for the development, utilization and rational allocation of the surface water resources in North China.

The Turpan basin is one of the most arid and water-insecure regions in China. Turpan Basin has a continental desert climate as it is located in central Eurasia and surrounded by mountains on all sides, with the lowest elevation of 154.5 m below sea level. Its rivers and water availability are mainly supplied by mountain snowmelt through surface streams and the Karez system. To assess the impact of climate change on streamflow in the Turpan basin, this study examined the long-term trends and change points of hydro-meteorological variables and explored the plausible correlation between them at annual and seasonal scales. A set of non-parametric statistical tests was applied to analyze the trend, its magnitude, and the change point of the hydro-meteorological variables from 1959 to 2012 in the Turpan basin. Results showed that the annual mean temperature had a significant increasing trend with an average warming rate of 0.26 °C/decade. Annual precipitation did not show a consistent upward or downward trend across the basin; however, there was a significant increase in winter precipitation. The increasing rates of streamflow at Alagou and Meiyaogou hydrological stations were the highest in the summer (0.42 and 0.18 m3/s per decade, respectively), which might increase the risk of flooding. The change points of various meteorological variables and streamflow can be generally found in the 1980s, in which temperature, precipitation, relative humidity, and streamflow had abrupt changes concurrently in 1986 and had respectively increased by 7.2, 41.3, 5.7, and 18.3% after 1986. In general, the strength of the relationship between annual streamflow and precipitation (0.34) was greater than that between streamflow and temperature (0.16). The significant increase in temperature and agriculture in the basin in recent decades indicates the importance of reducing unnecessary soil evaporation in agriculture to preserve water resources under climate change and using innovative technology to preserve soil quality under increasing evapotranspiration and irrigation. This study provided valuable information for understanding the changing properties of the streamflow in the basin and insights for better-integrated water resources management planning that focuses on mitigating flood disasters and soil degradation and improving irrigation efficiency.

The turbidite-hosted Au-Sb-Hg deposits in the Sandu-Danzhai area are distributed along the southwestern marginal fault of the Jiangnan Orogen, yet any genetic link among the Au, Sb and Hg mineralization and their respective ore-forming process remain unclear. Here, we investigate the Paiting Au(-Hg) and Miaolong Au-Sb deposits and present a new metallogenic model based on detailed petrographic observations, and in-situ trace element (EPMA and LA-ICP-MS) and sulfur isotope (fs-LA-MC-ICPMS) analyses on sulfide minerals. Our results show that the ore formation in the Sandu-Danzhai metallogenic belt (SDMB) can be divided into Au (pyrite + arsenopyrite + dolomite), Au-Sb (pyrite + arsenopyrite + stibnite + quartz), Sb (stibnite + native antimony + barite + dolomite + quartz) and Hg (cinnabar + calcite) stages, based on mineral paragenetic and vein crosscutting relationships. Trace element compositions suggest that progressive As enrichment in pyrite is accompanied by increasing Au, Sb and Cu contents, implying that these elements may have been leached from the same source via fluid-rock reactions. Sulfur isotope compositions of the sulfates and sulfides in the Au-Sb-Hg ores reveal that the sulfur was originated from thermal-chemical sulfate reduction (TSR) of marine sulfates in the Cambrian ore-bearing strata. Thus, we propose that deep metamorphic fluids (as evidenced from the high fluid CO2 and CH4 contents) may have promoted ore-material (e.g., Au, Sb, As, Hg) mobilization in the metamorphic basement and/or Cambrian strata. As for the metal transport and precipitation mechanism, fluid-rock interaction may have decreased the ore-fluid As content and caused auriferous pyrite precipitation. Meanwhile, changes in temperature and oxygen-sulfur fugacity may have significantly decreased Sb solubility, leading to extensive stibnite precipitation. Cinnabar associated with calcite was likely deposited via carbonate dissolution in the Cambrian strata in late hydrothermal (waning) stage. Overall, we propose that the Au-Sb-Hg deposits in the SDMB are best classified as orogenic type, and the metallogeny was controlled by boundary faults of the Jiangnan Orogen.

Mantle plume rich in gold is considered to be important for the formation of giant epigenetic gold deposits. The Youjiang ba-sin, SW China, is the world's second largest Carlin-type gold province, but the ultimate source of its gold remains enigmatic. In this study, we report that the Middle-Late Permian basaltic rocks in the basin are rich in native gold grains. These gold grains are scattered in the interstices of pyrite and mar-casite and in the amorphous silica cavities. Mineralogy and S-Pb isotope geochemistry of the auriferous sulfides suggest that the gold was largely derived from the gold-rich Late Permian (ca. 260 Ma) Emeishan plume and was released to a near-surface volcanogenic massive sulfide (VMS) metallogenic system, where it accumulated. The native gold grains from the basalts may have been inherited by the younger (ca. 140 Ma) Carlin-type ores in the Youjiang basin, which are indicative of gold pre-enrichment in the basin. Our study highlights that golden plume upwelling could carry abundant gold into the upper crust, even into shallow-level metallogenic systems, and thus provides an alternative view on the source of gold in the Youjiang basin.

Yunnan-Guizhou-Guangxi region,one of the most important gold mineralization areas in China,hosts many high temperature magmatic hydrothermal gold（copper） deposits,such as Pulang gold-bearing porphyry copper deposit,Beiya and Yaoan gold deposits,and low temperature hydrothermal gold deposits,namely carlin-type gold deposit,such as Badu,Nibao and Shuiyindong gold deposits.A lot of chemical studies of minerals,such as magnetite,pyrite and apatite have been carried out,and the abundant mineralogical geochemical data of trace elements in situ have been accumulated. However,the source materials and formation process of the deposits are still be disputed.Therefore,further statistical and comparative analyses of these data may provide a basis for revealing metallogenic information and guiding prospecting exploration. Due to the unique chemical characteristics,apatite can better preserve the important information of magma-hydrothermal evolution process,and is often used to define the fine metallogenic process of ore deposits. In this paper,the trace elements of hydrothermal apatite in high-temperature magma-hydrothermal deposits（Yao’an gold deposit and Pulang gold-bearing copper deposit） and low-temperature carlin-type gold deposits（Badu and Nibao gold deposits） have been collected and analyzed. It is found that the apatite in the high-temperature alkali-rich porphyry gold（copper） deposit is characterized by automorphic shape,high F and Cl contents,enriched LREE,and depleted HREE.In contrast,the apatite in the low-temperature carlin-type gold deposits is characterized by hypautomorphic and xenomorphic shapes,low F and Cl contents,enriched MREE. In addition,the δEu-δCe binary diagram and chondrite-normalized REE patterns revealed that the carlin-type gold deposits have higher oxygen fugacity than magmatic hydrothermal copper and gold deposits. Combined with the geochemical analysis of rare earth elements of stibnite in the Youjiang Basin,it is concluded that the enrichment characteristics of MREE in apatite（including fluorite and calcite） indicate that the low-temperature mineralizing fluid may be related to the special basin basement rock. In conclusion,apatite has unique geochemical characteristics in high temperature-medium and low temperature gold deposits,which can effectively reveal the type of ore deposit and the evolution process of ore-forming fluid.

It is of great significance to study and analyze the surface water resources and their change trend in the groundwater overexploitation area of the North China Plain, which is of great significance to solve the shortage of water resources in the groundwater overexploitation area of the North China Plain, promote the exploitation of groundwater, and realize the sustainable development of water resources. This paper takes Minyou Irrigation District of Handan City, a typical overexploitation area in the North China Plain, as an example. Based on the measured rainfall and runoff data from 1957 to 2020, the Mann–Kendall trend test, cumulative anomaly method, double cumulative curve method, and Morlet wavelet transform were used to analyze and predict the trend of water resources in the irrigation area and the individual contribution of climate change and human activities to runoff change. The results show that the annual rainfall and annual runoff in the irrigation area have a significant downward trend and significant cyclical changes throughout the study period. In 1977, the annual runoff showed a sudden change, and the average contribution rates of climate change and human activities to its change were 40.55% and 59.46%, respectively. In the future (2020–2035), runoff will remain stable and rainfall will show an increasing trend. The research results can provide scientific reference for the development, utilization, and rational allocation of surface water resources in the groundwater overexploitation area of the North China Plain.

贵州烂泥沟金矿床是国家发现最早的卡林型金矿之一,该矿床自发现以来,迅速引起了大量专家、学者的广泛关注,经过 40 多年的研究,取得了丰硕的研究成果与认识.烂泥沟金矿是国家非常具有代表性的卡林型金矿床之一,且探明储量相当可观.因此,系统研究烂泥沟金矿床的成矿规律对类似矿床寻求找矿突破具有重要意义.文章通过对烂泥沟金矿床研究资料的搜集整理,总结了烂泥沟金矿的成矿地层、控矿构造,同时对烂泥沟金矿床的成矿物质来源、成矿年龄及矿床成因作了相关总结和介绍,并对可能的有利成矿部位进行了探讨.

The Machangqing Cu-Mo deposit, located in the Sanjiang Tethyan metallogenic belt, is a polymetallic deposit related to the intrusion of alkaline porphyry in the Himalayan period. Previous studies have shown that the Machangqing Cu-Mo polymetallic deposit was formed in a porphyry-skarn metallogenic system. However, due to the lack of systematic mineralogical research, a mineralization process and metallogenic effects of skarn are still unclear, limiting a comprehensive understanding of the mineralization process of this deposit. Herein, this paper considers garnet in skarn mineralization in Machangqing deposit as the research object, and uses H-O isotope, electron probe（EPMA） and LA-ICP-MS in-situ microregion technology to carry out isotope and composition analysis to define the source of ore-forming fluids and invert the evolution process of ore-forming fluids. The garnets can be divided into early euhedral garnets（Grt I） and late anhedral type（Grt II）. The Grt I, coexisting with the pyroxene, pyrite and chalcopyrite, belongs to the grossular-andradite garnet solid solution(And 49.37～99.58 Gro 0～49.79 ). The Grt II has elevated Fe compared to Grt I, and mainly consists of andradite(And 67.5～99.85 Gro 0～31.84 ). Both the types of garnets are enriched in Th, U, LREEs and Nd, depleted in Ba, Sr, Hf and Nb. Based on the chemical compositions of garnet, the Grt I may have formed under mildly acidic, oxidized and low W/R conditions, whereas the Grt II may have formed under acidic, oxidation, and high W/R conditions. In addition, the δD V-SMOW values and δ 18 O fluid values of these garnets range from-122.6‰ to-98.6‰ and 5.95‰ to 8.25‰, respectively, implying that the hydrothermal ore-forming fluid originated from magma-derived fluid. A comprehensive consideration of data indicated that the oxygen fugacity and temperature of the ore-forming fluid presented a decreasing trend during the skarn mineralization process, and the pH of the fluid gradually changes from acid to weak acid neutral. This process may have been the main mechanism to trigger the precipitation of skarn type mineralized copper molybdenum sulfide in the Machangqing deposit.

黔东南金成矿区位于江南造山带金成矿省的西南端,成矿条件优越.坑头金矿床是黔东南金成矿区的一个中型矿床,在其深部找矿中,发现除石英脉型矿体外,还存在蚀变岩型矿体.然而,这种蚀变岩型矿体的构造形态、蚀变类型、与石英脉型矿体之间关系和金的赋存状态尚不清楚.本研究与当前的勘查工作紧密结合,围绕石英脉型矿体和新发现的蚀变岩型矿体为研究切入点,借助微区分析技术(扫描电镜和电子探针)进行系统的"流体-蚀变-成矿"研究.蚀变矿物金红石矿物化学显示为热液成因,具有典型造山型金矿床的金红石标型特征.围岩的沉积-成岩过程(包括低级变质作用过程),主要形成了草莓状黄铁矿和含铁碳酸盐岩,为后期含金硫化物(黄铁矿和毒砂)的形成提供物质基础(如Fe).金的成矿富集过程主要经历了绢云母+毒砂+黄铁矿+石英(Ser+Apy+Py+Qtz)阶段、黄铁矿+毒砂+石英(Py+Apy+Qtz)阶段和自然金+石英(Au0+Qtz)阶段.在Ser+Apy+Py+Qtz阶段,主要表现为含矿流体与围岩的初级交代,形成大量浸染状黄铁矿+毒砂的硫化带;Py+Apy+Qtz阶段主要为流体沿着剪切带再交代,形成蚀变岩型矿体;Au0+Qtz阶段主要表现为含金石英大脉的形成.金的赋存状态研究显示,蚀变岩矿体中Au以他形显微-次显微自然金赋存在蚀变岩硫化物裂隙中,或以化学结合态方式赋存在黄铁矿和毒砂中(后者占主导).在晚期Au0+Qtz阶段,自然金呈自形、粗粒(～0.5 mm)赋存在石英脉中.综合研究认为,多期构造(流体)交代导致的溶解-再沉淀可能是坑头金富集成矿主要原因之一.

贵州晴隆锑矿床是右江盆地低温热液矿集区代表性锑矿床,硅化普遍发育.本文通过系统的岩相学研究,认为晴隆锑矿床硅化可分为3期:第1期硅化主要形成于大厂层沉积-成岩自蚀变过程,表现为火山玻屑脱玻化重结晶作用;第2期硅化与锑矿化关系密切;而第3期硅化为热液成矿晚阶段产物,与晚期脉状锑-金矿化相关.围岩、硅化围岩和矿石主微量元素分析显示,富Si流体呈酸性使灰岩中大量的CaCO3矿物溶解,同时伴生强烈的热液钾化蚀变,Sb、As、Au、S、K等元素由热液带入,Ca和Na为带出.综合分析认为,大厂层不仅为流体运移提供通道,同时为成矿提供了的充足空间和水/岩反应物质基础,如为硫化物沉淀和脉石(方解石和萤石)沉淀提供Fe和Ca等.

The genesis of the typical Hg-Au-Sb metallogenic district in the southwestern margin of the Yangtze Craton, Southwestern China, remains controversial. A systematic study of the mercury (Hg) concentrations and Hg isotopic compositions of the Hg deposit at Paiting was conducted to constrain the sources of metals. Mass -independent fractionation (MIF) of Hg isotopes with slight positive & UDelta;199Hg (0.03%o to 0.22%o) was observed in the Hg ore samples, indicating that Hg transported by the ore fluids was primarily derived from the Cambrian black shale as these rocks show similar & UDelta;199Hg signatures (-0.02%o to 0.08%o). Based on these newly obtained Hg isotope ratios, we propose that deep hydrothermal fluids promoted the mobilization of Hg in Hg-bearing strata (i.e., Cambrian Niutitang Formation black shale) in the paleo-basin sedimentary strata to form Hg -enriched fluids. The Hg-enriched fluids flowed and permeated from the lower to the upper strata during mineralization and were transported to the platform margin slope facies along faults, followed by Hg precipi-tation to form Hg deposits. Hg isotope ratios could be a robust tracer to distinguish the metal sources of hy-drothermal Hg deposits.

Traditional multi-parameter single distribution quantile mapping (QM) methods excel in some respects in correcting climate model precipitation, but are limited in others. Multi-parameter mixed distribution quantile mapping can potentially exploit the strengths of single distribution methods and avoid their weaknesses. The correction performance of mixed distribution QM methods varies with the geographical location they are applied to and the combination of distributions that are included. This study compares multiple sets of single distribution and multi-parameter mixed distribution QM methods in order to correct the precipitation bias in the upper reaches of the Yangtze River basin (UYRB) in RegCM4 simulated precipitation. The results show that, among the selected distributions, the gamma distribution has the highest performance in the basin; explaining more than 50% of the precipitation events based on the weighting coefficients. The Gumbel distribution had the worst performance, only explaining about 10% of the precipitation events. The performance parameters, such as the root mean square error (RMSE) and the correlation coefficient (R) of the corrected precipitation, that were derived by using mixed distribution were better than those derived by using single distribution. The QM method that is based on the gamma-generalized extreme value distribution best corrected the precipitation, could reproduce the annual cycle and geographical pattern of observed precipitation, and could significantly reduce the wet bias from the RegCM4 model in the UYRB. In addition to enhancing precipitation climatology, the correction method also improved the simulation performance of the RegCM4 model for extreme precipitation events.

In the northwestern margin of the Youjiang basin (NWYB) in SW China, many Carlin-like gold deposits are highly antimony (Sb)-rich, and many vein-type Sb deposits contain much Au. These deposits have similar ages, host rocks, ore-forming temperatures, ore-related alterations and ore mineral assemblages, but the Au and Sb metallogenic relations and their ore-forming process remain enigmatic. Here we investigate the large Qinglong Sb deposit in the NWYB, which has extensive sub-economic Au mineralization, and present a new metallogenic model based on in-situ trace elements (EPMA and LA-ICP-MS) and sulfur isotopes (NanoSIMS and fs-LA-MC-ICP-MS) of the ore sulfides. At Qinglong, economic Sb ores contain coarse-grained stibnite, jasperoid quartz and fluorite, whilst the sub-economic Au–Sb ores comprise dominantly veined quartz, arsenian pyrite and fine-grained stibnite. Three generations of ore-related pyrite (Py1, Py2 and Py3) and two generations of stibnite (Stb1 and Stb2) are identified based on their texture, chemistry, and sulfur isotopes. The pre-ore Py1 is characterized by the lower ore element (Au, As, Sb, Cu and Ag) contents (mostly below the LA-ICP-MS detection limit) and Co/Ni ratios (average 0.31) than the ore-stage pyrites (Py2 and Py3), implying a sedimentary/diagenetic origin. The Py2 and Py3 have elevated ore element abundance (maximum As ​= ​6500 ​ppm, Au ​= ​22 ​ppm, Sb ​= ​6300 ​ppm, Cu ​= ​951 ​ppm, Ag ​= ​77 ​ppm) and Co/Ni ratios (average 1.84), and have positive As vs. Au–Sb–Cu–Ag correlations. Early-ore Stb1 has lower As (0.12–0.30 ​wt.%) than late-ore Stb2 (0.91–1.20 ​wt.%). These features show that the progressive As enrichment in ore sulfides is accompanied by increasing Au, Sb, Cu and Ag with the hydrothermal evolution, thereby making As a good proxy for Au. As-rich, As-poor and As-free zones are identified via NanoSIMS mapping of the Au-bearing pyrite. The As-rich zones in the Qinglong Au-bearing pyrites (Py2 and Py3) and ore stibnites (Stb1 and Stb2) have narrow δ34SH2S ranges (−8.9‰ to +4.1‰, average −3.1‰) and −2.9‰ to +6.9‰, average ​+ ​1.3‰), respectively, indicating that the Au-rich and Sb-rich fluids may have had the same sulfur source. Published in-situ sulfur isotopic data of pyrite As-rich zones from other Carlin-like Au deposits (Shuiyindong, Taipingdong, Nayang, Getang and Lianhuashan) in the NWYB have similar ore-fluid δSH2S34 values (−4.5‰ to +6.7‰, average −0.6‰) to those of Qinglong. Therefore, we infer that the sulfur of both Au and Sb mineralization was derived from the same magmatic-related source (0 ​± ​5‰) in the NWYB.Moreover, the core of pyrites (Py1) has variable S isotope fractionation (−18.9‰ to +18.1‰, mostly +3‰ to +12‰), suggesting that the higher-34S H2S was produced by bacterial sulfate reduction (BSR). The hydrothermal pyrite (Py2 and Py3) δ34S values gradually decrease with increasing As concentrations, and ultimately, within the restricted range (−5‰ to +5‰) in As-rich zones. This variation implies that the As-rich pyrite was formed through ongoing interactions of the magmatic-hydrothermal fluid with pre-existing sedimentary pyrites, causing the progressive decreasing δ34S values with As content increase, Hence, the fluid/mineral interaction may have generated the observed variation in δ34S and As contents. Overall, comparing the Au and Sb deposits in the NWYB, we favor a magmatic-related source for the Au–Sb–As-rich fluids, but the Au- and Sb-ore fluids were likely evolved at separate stages in the ore-forming system.