Crop root system plays an important role in the water cycle of the soil-plant-atmosphere continuum. In this study, com- bined isotope techniques, root length density and root cell activity analysis were used to invest...Crop root system plays an important role in the water cycle of the soil-plant-atmosphere continuum. In this study, com- bined isotope techniques, root length density and root cell activity analysis were used to investigate the root water uptake mechanisms of winter wheat （Triticum aesfivum L.） under different irrigation depths in the North China Plain. Both direct inference approach and multisource linear mixing model were applied to estimate the distribution of water uptake with depth in six growing stages. Results showed that winter wheat under land surface irrigation treatment （Ts） mainly absorbed water from 10-20 cm soil layers in the wintering and green stages （66.9 and 72.0%, respectively）; 0-20 cm （57.0%） in the jointing stage; 0-40 （15.3%） and 80-180 cm （58.1%） in the heading stage; 60-80 （13.2%） and 180-220 cm （35.5%） in the filling stage; and 0-40 （46.8%） and 80-100 cm （31.0%） in the ripening stage. Winter wheat under whole soil layers irrigation treatment （Tw） absorbed more water from deep soil layer than Ts in heading, filling and ripening stages. Moreover, root cell activity and root length density of winter wheat under TW were significantly greater than that of Ts in the three stages. We concluded that distribution of water uptake with depth was affected by the availability of water sources, the root length density and root cell activity. Implementation of the whole soil layers irrigation method can affect root system distribution and thereby increase water use from deeper soil and enhance water use efficiency.展开更多
Hundreds of precipitation samples collected from meteorological stations in the Ordos Basin from January 1988 to December 2005 were used to set up a local meteoric water line and to calculate weighted average isotopic...Hundreds of precipitation samples collected from meteorological stations in the Ordos Basin from January 1988 to December 2005 were used to set up a local meteoric water line and to calculate weighted average isotopic compositions of modern precipitation. Oxygen and hydrogen isotopes, with averages of-7.8‰ and -53.0‰ for δ^18O and δD, respectively, are depleted in winter and rich in spring, and gradually decrease in summer and fall, illustrating that the seasonal effect is considerable. They also show that the isotopic difference between south portion and north portion of the Ordos Basin are not obvious, and the isotope in the middle portion is normally depleted. The isotope compositions of 32 samples collected from shallow groundwater （less than a depth of 150 m） in desert plateau range from -10.6‰ to -6.0‰ with an average of-8.4‰ for δ^18O and from -85‰ to -46‰ with an average of-63‰ for δD. Most of them are identical with modern precipitation. The isotope compositions of 22 middle and deep groundwaters （greater than a depth of 275 m） fall in ranges from -11.6‰ to -8.8‰ with an average of -10.2‰ for δ^18O and from -89‰ to -63‰ with an average of -76‰ for δD. The average values are significantly less than those of modern precipitation, illustrating that the middle and deep groundwaters were recharged at comparatively lower air temperatures. Primary analysis of ^14C shows that the recharge of the middle and deep groundwaters started at late Pleistocene. The isotopes of 13 lake water samples collected from eight lakes define a local evaporation trend, with a relatively flat slope of 3.77, and show that the lake waters were mainly fed by modern precipitation and shallow groundwater.展开更多
According to the hydrochemical characteristics, hydrogen and oxygen isotope characteristics and the ratio of noble gas isotopes of the sandstone aquifer and basalt aquifer, this study calculated the recharge temperatu...According to the hydrochemical characteristics, hydrogen and oxygen isotope characteristics and the ratio of noble gas isotopes of the sandstone aquifer and basalt aquifer, this study calculated the recharge temperature and residence time of groundwater in the Weishan area of Wudalianchi, also calculating the contribution of noble gas components from different sources to the samples. Based on the characteristics of hydrogen and oxygen isotopes and noble gases Xe and Ne, the recharge altitude and recharge temperature of the two aquifers were estimated, and the recharge temperature fitting with the NGT model as verified, the results showing that the main recharge altitude of groundwater in the region was 500–600 m, the recharge temperature being 2–7°C. He_(eq) and He_(ea) of the samples have been simulated using the OD model, the content of radioactive ~4He in the crust being obtained, the groundwater ages under the two conditions(closed condition and open condition) both being simulated. The results show that groundwater from the sandstone layer water is older than groundwater from the basalt layer. Hydrochemical characteristics and noble gas isotope ratios indicate that in the basalt aquifer and sandstone aquifer in the Weishan area, in addition to atmospheric and crustal helium, there is also an input of mantle-derived helium. The fault constitutes the uplift channel for groundwater containings mantle components, which results in the mantle source composition in water samples near the fault being much higher than those form non-fault areas.展开更多
The Badi copper deposit is located in Shangjiang town, Shangri-La County, Yunnan Province. Tectonically, it belongs to the Sanjiang Block. Vapor-liquid two-phase fluid inclusions, CO2-bearing fluid inclusions, and dau...The Badi copper deposit is located in Shangjiang town, Shangri-La County, Yunnan Province. Tectonically, it belongs to the Sanjiang Block. Vapor-liquid two-phase fluid inclusions, CO2-bearing fluid inclusions, and daugh- ter-beating inclusions were identified in sulfide-rich quartz veins. Microthermometric and Raman spectroscopy studies revealed their types of ore-forming fluids： （1） low-tem- perature, low-salinity fluid; （2） medium-temperature, low salinity CO2-bearing; and （3） high-temperature, Fe-rich, high sulfur fugacity. The δ^18O values of chalcopyrite- bearing quartz ranged from 4.96‰ to 5.86%0, with an average of 5.40%0. The δD values of ore-forming fluid in equilibrium with the sulfide-bearing quartz were from - 87‰ to - 107‰, with an average of - 97.86%0. These isotopic features indicate that the ore-forming fluid is a mixing fluid between magmatic fluid and meteoric water. The δ^34S values of chalcopyrite ranged from 13.3‰ to 15.5‰, with an average of 14.3‰. Sulfur isotope values suggest that the sulfur in the deposit most likely derived from seawater. Various fluid inclusions coexisted in the samples; similar homogenization temperature to different phases suggests that the Badi fluid inclusions might have been captured under a boiling system. Fluid boiling caused by fault activity could be the main reason for the mineral precipitation in the Badi deposit.展开更多
The Ordovician was an important transitional period for global climate and organic evolution,the global was in the flood and glacial,Onganism was extinction(Zhan,2007;Trotter et al.,2008;Axel et al.,2010).Under the in...The Ordovician was an important transitional period for global climate and organic evolution,the global was in the flood and glacial,Onganism was extinction(Zhan,2007;Trotter et al.,2008;Axel et al.,2010).Under the influence展开更多
Recent studies suggest that the hydrogen and oxygen isotopic compositions of clay minerals can indicate paleoclimate.Here,we report mineralogy and stable isotopic records(d D and δ^(18)O_(OH))of a weathering profile ...Recent studies suggest that the hydrogen and oxygen isotopic compositions of clay minerals can indicate paleoclimate.Here,we report mineralogy and stable isotopic records(d D and δ^(18)O_(OH))of a weathering profile located in the Fujian Province,aiming to validate whether hydroxyl stable isotopes can indicate paleo-precipitation and paleo-temperature.Our results indicate that the d D and δ^(18)O_(OH)changes in the kaolinite hydroxyl of the weathering profile are basically determined by the isotopic composition of paleo-meteoric water and paleotemperature,respectively.Nevertheless,whether the d D and δ^(18)O_(OH)of kaolinite can quantitatively indicate paleo-precipitation and paleo-temperature needs to be verified further,and especially,the structural oxygen isotopic composition that is the essential element for the kaolinite formation temperature calculation has to be constrained in future work.展开更多
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,w...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.展开更多
New oxygen and hydrogen isotope ratios of chert from middle, intraformational breccias, and upper breccia members of the Sixtymile Formation（SMF） in eastern Grand Canyon National Park（AZ） yield palaeoclimate estim...New oxygen and hydrogen isotope ratios of chert from middle, intraformational breccias, and upper breccia members of the Sixtymile Formation（SMF） in eastern Grand Canyon National Park（AZ） yield palaeoclimate estimates between 27 and 33℃. The isotopic compositions of cherts define a domain approximately parallel to the meteoric water line when plotted on a δD–δ-（18）O diagram; these data indicate that meteoric water was involved during formation of the chert. In thin section, the absence of interlocking mega quartz（〉35 lm） and silicafilled fractures and veins, along with preserved micromorphological silica fabrics, suggest that the chert has not been permeated by later hydrothermal fluids. Petrographic observations in thin section such as cyclic silica precipitation phases and glaebular micromorphologic fabrics lend support to the interpretation that meteoric waters were involved during chert precipitation. The post 742 Ma SMF has been correlated with diamictite（transition） beds of the Kingston Peak Formation（CA）, which in turn have been interpreted to have been deposited during the Sturtian Ice Age（-750–700 Ma）. Absence of facetted and striated clasts and other diagnostic glaciogenic features in the SMF,an unconformable contact with the stratigraphically older Chuar Group, coupled with warm palaeotemperature data inferred from stable isotope values of chert, tentatively suggest that deposition of sediment in the SMF likely did not take place during the Sturtian Ice Age.展开更多
Despite the increasing depletion of the groundwater at the Zhangjiakou aquifer system in the northwest of Beijing-Tianjin-Hebei region,little information is available on the hydrological process of groundwater in this...Despite the increasing depletion of the groundwater at the Zhangjiakou aquifer system in the northwest of Beijing-Tianjin-Hebei region,little information is available on the hydrological process of groundwater in this region.In this study,we utilized water isotopes composition(51sO,5D and 3H)of groundwater,river and precipitation to identify the characteristics of hydrochemistry,groundwater age and recharge rates in different watersheds of the Zhangjiakou area.Results showed that the river water and groundwater could be characterized as HCO3-Mg Na,HCO3 CI-Na and HCO3-Mg Na,HCO3 CI-Na,HCO3 CI-Na Mg types,respectively.The 5D and 5180 values in precipitation were linearly correlated,which is similar to the Global Meteorological Water Line(GMWL).Furthermore,the decreasing values of the 6D and 5180 from precipitation to surface water and groundwater indicate that groundwater is mainly recharged by atmospheric precipitation.In addition,the variation of 3H concentration with depth suggests that groundwater shallower than around 100 m is generally modern water.In contrast,groundwater deeper around 100 m is a mixture of modern and old waters,which has longer residence times.Groundwater showed a relatively low tritium concentration in the confined aquifers,indicating the groundwater recharged might be relatively old groundwater of over 60 years.The flow velocity of the groundwater in the study area varied from 1.10 to 2.26 m/a,and the recharge rates ranged from 0.034 to 0.203 m/a.The obtained findings provide important insights into understanding the groundwater recharge sources and hydrochemistry in the Zhangjiakou area,in turn developing a sustainable groundwater management plan.展开更多
The Baiyun deposit is a large gold deposit at the western end of the Liaoji rift zone in Liaoning Province, which has produced both auriferous quartz-vein type and altered-rock type mineralization. The ore bodies are ...The Baiyun deposit is a large gold deposit at the western end of the Liaoji rift zone in Liaoning Province, which has produced both auriferous quartz-vein type and altered-rock type mineralization. The ore bodies are mainly hosted in schist from the Gaixian Formation of the Liaohe Group. A detailed field geological survey showed that the quartz-vein type gold ore bodies are distributed in the near EW-trending and occur in the extensional tectonic space of schist in the Gaixian Formation, and the altered-rock type gold ore bodies are distributed in the near EW-trending structural belt and occur near in the Gaixian Formation of biotite schist, biotite granulite, marble and the upper footwall of dike. To further elucidate the source of ore-forming fluid and material in the Baiyun gold deposit, the H-O isotopes for quartz, S and Pb isotopes, in-situ trace elements for sulfides from quartz-vein and altered-rock type mineralization were studied. The H-O isotopic δD_(V-SMOW) and δ^(18)O_(H2O) values of the auriferous quartz range were from-88.8‰ to-82.2‰ and-1.95‰ to 4.85‰, respectively, suggests that the ore-forming fluids were mainly magmatic water with minor meteoric water. The distribution ranges of in-situ S isotopic compositions of Au-bearing pyrite in the quartz-vein type and altered-rock type ores were-8.38‰–-10.47‰(with average values of-7.89‰) and 11.38‰– 17.52‰(with average values of 11.55‰), respectively, indicating that the S isotopic compositions of the two ore types were clearly different. The in-situ Pb isotopic ratios changed almost uniformly, which showed that they had the same lead isotopic source. Based on the analysis of S and Pb isotopic compositions, the metallogenic materials in the Baiyun gold deposit were primarily from deep magma, and some wall rock materials may have been mixed in the metallogenic process. Co/Ni diagram shows that most Au-bearing pyrites have magmatic-hydrothermal or sedimentary alteration properties, and Au/As ratios were between 0.001 and 0.828(the average value was 0.07), indicating that the ore-forming fluid in the Baiyun gold deposit may have been deep magma. Combining the geological, trace element, and isotopic data, as well as data from previous studies, we propose that the Baiyun gold deposit is a magmatic-hydrothermal ore deposit.展开更多
The Ciemas gold deposit is located in West Java of Indonesia,which is a Cenozoic magmatism belt resulting from the Indo-Australian plate subducting under the Eurasian plate.Two different volcanic rock belts and associ...The Ciemas gold deposit is located in West Java of Indonesia,which is a Cenozoic magmatism belt resulting from the Indo-Australian plate subducting under the Eurasian plate.Two different volcanic rock belts and associated epithermal deposits are distributed in West Java:the younger late Miocene-Pliocene magmatic belt generated the Pliocene-Pleistocene epithermal deposits,while the older late Eocene-early Miocene magmatic belt generated the Miocene epithermal deposits.To constrain the physico-chemical conditions and the origin of the ore fluid in Ciemas,a detailed study of ore petrography,fluid inclusions,laser Raman spectroscopy,oxygen-hydrogen isotopes for quartz was conducted.The results show that hydrothermal pyrite and quartz are widespread,hydrothermal alteration is well developed,and that leaching structures such as vuggy rocks and extension structures such as comb quartz are common.Fluid inclusions in quartz are mainly liquid-rich two phase inclusions,with fluid compositions in the NaCl-H_(2)O fluid system,and contain no or little CO_(2).Their homogenization temperatures cluster around 240℃-320℃,the salinities lie in the range of 14-17 wt.%NaCl equiv,and the calculated fluid densities are 0.65-1.00 g/cm^3.The values ofδ18OH2O-VSMOW for quartz range from+5.5%0 to+7.7‰,theδDVSMOW of fluid inclusions in quartz ranges from-70‰to-115‰.All of these data indicate that mixing of magmatic fluid with meteoric water resulted in the formation of the Ciemas deposit.A comparison among gold deposits of West Java suggests that Miocene epithermal ore deposits in the southernmost part of West Java were more affected by magmatic fluids and exhibit a higher degree of sulfidation than those of Pliocene-Pleistocene.展开更多
Studying spatial and temporal characteristics of regional groundwater recharge will guide the scientific management and sustainable development of regional water resources.This study investigated stable isotopes(δ^(1...Studying spatial and temporal characteristics of regional groundwater recharge will guide the scientific management and sustainable development of regional water resources.This study investigated stable isotopes(δ^(18)O andδ^(2)H)of precipitation,groundwater,river water and lake water during 2019-2020 in Qinghai Lake Basin to reveal the spatial and temporal characteristics of groundwater recharge.The local meteoric water line was simulated using ordinary least squares regression(δ^(2)H=7.80δ^(18)O+10.60).The local evaporation lines of the river water,lake water and groundwater were simulated asδ^(2)H=6.21δ^(18)O-0.72,δ^(2)H=5.73δ0-3.60 andδ^(2)H=6.59δ0+1.76,respectively.Theδ^(2)H andδ^(18)O of river water and groundwater were in more depleted values due to the recharge by precipitation at high altitudes or precipitation effects,and theδ^(2)H andδ^(18)O of the lake water were in more enriched values because of evaporation.The relationship between theδ^(2)H andδ^(18)O of groundwater and river water was not significantly different,indicating a strong hydrological connection between the groundwater and river water surrounding Qinghai Lake.Additionally,the maximum values ofδ^(18)O and the minimum values of lc-excess of groundwater in most regions were both in August,and the minimum values ofδ^(18)O and the maximum values of lc-excess of groundwater in most regions were both in October.Therefore,the groundwater was recharged by soil water with strong evaporation in August and recharged by precipitation at high altitudes in October.The recharge rate of groundwater was relatively fast in areas with large slopes and large hydraulic gradients(e.g.,south of Qinghai Lake),and in areas with strong hydrological connections between the groundwater and river water(e.g.,the Buha River Valley).Those results can provide data support for protection and utilization of water resources in Qinghai Lake Basin,and provide reference for groundwater research in closed lake basins on the Qinghai-Tibet Plateau.展开更多
In order to investigate the transformation among the precipitation,groundwater,and surface water in the Sanjiang Plain,Northeast China,precipitation and groundwater samples which were collected at the meteorological s...In order to investigate the transformation among the precipitation,groundwater,and surface water in the Sanjiang Plain,Northeast China,precipitation and groundwater samples which were collected at the meteorological station of the Sanjiang Mire Wetland Experimental Station,Chinese Academy of Sciences and the surface water which collected from the Wolulan River were used to identify the transformation of three types of water.The isotope composition of different kinds of water sources were analyzed via stable isotope(deuterium and oxygen-18) investigation of natural water.The results show a clear seasonal difference in the stable isotopes in precipitation.During the cold half-year,the mean stable isotope in precipitation in the Sanjiang Plain reaches its minimum with the minimum temperature.The δ18O and δD values are high in the rainy season.In the Wolulan River,the evaporation is the highest in August and September.The volume of evaporation and the replenishment to the river is mostly same.The groundwater is recharged more by the direct infiltration of precipitation than by the river flow.The results of this study indicate that the water bodies in the Sanjiang Plain have close hydrologic relationships,and that the transformation among each water system frequently occurs.展开更多
Located in Alxa Zuoqi (Left Banner) of Inner Mongolia, China, the Zhulazhaga gold deposit is the first large- scale gold deposit that was found in the middle-upper Proterozoic strata along the north margin of the Nort...Located in Alxa Zuoqi (Left Banner) of Inner Mongolia, China, the Zhulazhaga gold deposit is the first large- scale gold deposit that was found in the middle-upper Proterozoic strata along the north margin of the North China craton in recent years. It was discovered by the No. 1 Geophysical and Geochemical Exploration Party of Inner Mongolia as a result of prospecting a geochemical anomaly. By now, over 50 tonnes of gold has been defined, with an average Au grade of 4 g/ t. The ore bodies occur in the first lithological unit of the Mesoproterozoic Zhulazhagamaodao Formation (MZF), which is composed mainly of epimetamorphic sandstone and siltstone and partly of volcanic rocks. With high concentration of gold, the first lithological unit of the MZF became the source bed for the late-stage ore formation. Controlled by the interstratal fracture zones, the ore bodies mostly appear along the bedding with occurrence similar to that of the strata. The primitive ore types are predominantly the altered rock type with minor ore belonging to the quartz veins type. There are also some oxidized ore near the surface. The metallic minerals are composed mainly of pyrite, pyrrhotite and arsenopyrite with minor chalcopyrite, galena and limonite. Most gold minerals appear as native gold and electrum. Hydrothermal alterations associated with the ore formation are actinolitization, silicatization, sulfidation and carbonation. A total of 100 two-phase H 2 O-rich and 7 three-phase daughter crystal-bearing inclusions were measured in seven gold- bearing quartz samples from the Zhulazhaga gold deposit. The homogenization temperatures of the two-phase H 2 O-rich inclusions range from 155 to 401°C, with an average temperature of 284°C and bimodal distributions from 240 to 260°C and 300 to 320°C respectively. The salinities of the two-phase H 2 O-rich inclusions vary from 9.22wt% to 24.30wt% NaCl equiv, with a mode between 23 wt% and 24wt% NaCl equiv. Comparatively, the homogenization temperatures of the three- phase daughter crystal-bearing inclusions vary from 210 to 435°C and the salinities from 29.13wt% to 32.62wt% NaCl equiv. It indicates that the ore-forming fluid is meso-hypothermal and characterized by high salinity, which is apparently different from the metamorphic origin with low salinity. It suggests a magmatic origin of the gold-bearing fluid. The δ 18 O values of quartz from auriferous veins range from 11.9 to 16.3 per mil, and the calculated values in equilibrium with quartz vary from 1.06 to 9.60 per mil, which fall between the values of meteoric water and magmatic water. It reflects that the ore-forming fluid may be the product of mixing of meteoric water and magmatic water. Based on geological and geochemical studies of the Zhulazhaga gold deposit, it is supposed that the volcanism in the Mesoproterozoic might make gold pre-concentrate in the strata. The extensive and intensive Hercynian tectono-magmatic activity not only brought along a large number of ore-forming materials, but also made the gold from the strata rework. It can be concluded that the ore bodies were mainly formed in late hydrothermal reworking stage. Compared with typical gold deposits associated with epimetamorphic clastic rocks, the Zhulazhaga deposit has similar features in occurrence of ore bodies, ore-controlling structure, wall-rock alterations and mineral assemblages. Therefore, the Zhulazhaga gold deposit belongs to the epimetamorphic clastic rock type.展开更多
The Qaidam Basin is a large intermontane depression in Qinghai Province,China,which located on the northern margin of the Tibet plateau,and surrounded by the Qilian,Kunlun and Aljun mountains which rise to more than 5...The Qaidam Basin is a large intermontane depression in Qinghai Province,China,which located on the northern margin of the Tibet plateau,and surrounded by the Qilian,Kunlun and Aljun mountains which rise to more than 5000m.Some 27 salt lakes occur within the basin,occupying an area of approximately 1500 km2.Additionally,there are extensive areas of dry playas.Together,the playas and salt lakes cover about one quarter of the total basin area.Whereas the western展开更多
Sichuan Basin is one of the most important marine–salt forming basins in China. The Simian and Triassic have a large number of evaporites. The Triassic strata have found a large amount of polyhalite and potassium-ric...Sichuan Basin is one of the most important marine–salt forming basins in China. The Simian and Triassic have a large number of evaporites. The Triassic strata have found a large amount of polyhalite and potassium-rich brine. However, no soluble potassium salt deposit were found. In this study, the halite in well Changping 3 which is located at the eastern part of the Sichuan basin was studied using the characteristics, hydrogen and oxygen isotopes of the fluid inclusion in halite to reconstruct the paleoenvironment. The salt rocks in well Changping 3 can be divided into two types: grey salt rock and orange salt rock. The result shows that the isotopic composition of the halite fluid inclusion is distinct from the global precipitation line reflecting that the salt formation process is under strong evaporation conditions and the climate is extremely dry. At the same time, compared with the hydrogen and oxygen isotopes of brine in the Sichuan Basin and the hydrous isotope composition of the inclusions in the salt inclusions of other areas in China, it is shown that the evaporation depth of the ancient seawater in the Sichuan Basin was high and reached the precipitation of potassium and magnesium stage.展开更多
The variation of stable isotope ratios in natural waters provides valuable information that can be used to trace water movement. Evaporation plays a crucial role in determining the variation of stable isotopes. In thi...The variation of stable isotope ratios in natural waters provides valuable information that can be used to trace water movement. Evaporation plays a crucial role in determining the variation of stable isotopes. In this paper, several evaporation experiments were conducted in order to study the stable isotopic fractionation mechanism of water and analyze the influence of different temperatures on evaporation fractionation. Three group experiments of water evaporation under different temperatures and initial isotopic values were carried out. The results show that fractionation factors of hydrogen and oxygen may increase with temperature, and the average enrichment degree of hydrogen isotope D is 3.432 times that of oxygen isotope 18O. The results also show that the isotopic composition of the initial water has little influence on water evaporation fractionation, which is mainly affected by the state variables in the evaporation process, such as temperature. This research provides experimental data for further understanding the evaporation fractionation mechanism.展开更多
The Dahutang tungsten polymetallic ore field is located north of the Nanling W-Sn polymetallic metallogenic belt and south of the Middle—Lower Yangtze River Valley Cu-Mo-Au-Fe porphyry-skarn belt.It is a newly discov...The Dahutang tungsten polymetallic ore field is located north of the Nanling W-Sn polymetallic metallogenic belt and south of the Middle—Lower Yangtze River Valley Cu-Mo-Au-Fe porphyry-skarn belt.It is a newly discovered ore field,and probably represents the largest tungsten mineralization district in the world.The Shimensi deposit is one of the mineral deposits in the Dahutang ore field,and is associated with Yanshanian granites intruding into a Neoproterozoic granodiorite batholith.On the basis of geologic studies,this paper presents new petrographic,microthermometric,laser Raman spectroscopic and hydrogen and oxygen isotopic studies of fluid inclusions from the Shimensi deposit.The results show that there are three types of fluid inclusions in quartz from various mineralization stages：liquid-rich two-phase fluid inclusions,vapor-rich two-phase fluid inclusions,and three-phase fluid inclusions containing a solid crystal,with the vast majority being liquid-rich two-phase fluid inclusions.In addition,melt and melt-fluid inclusions were also found in quartz from pegmatoid bodies in the margin of the Yanshanian intrusion.The homogenization temperatures of liquid-rich two-phase fluid inclusions in quartz range from 162 to 363℃ and salinities are 0.5wt%-9.5wt%NaCI equivalent.From the early to late mineralization stages,with the decreasing of the homogenization temperature,the salinity also shows a decreasing trend.The ore-forming fluids can be approximated by a NaCl-H_2O fluid system,with small amounts of volatile components including CO_2,CH_4 and N_2,as suggested by Laser Raman spectroscopic analyses.The hydrogen and oxygen isotope data show that δ5D_（V-smow） values of bulk fluid inclusions in quartz from various mineralization stages vary from-63.8‰ to-108.4‰,and the δ^（18）O_（H2O） values calculated from the δ^（18）O_（V-）smow values of quartz vary from-2.28‰ to 7.21‰.These H-O isotopic data are interpreted to indicate that the ore-forming fluids are mainly composed of magmatic water in the early stage,and meteoric water was added and participated in mineralization in the late stage.Integrating the geological characteristics and analytical data,we propose that the ore-forming fluids of the Shimensi deposit were mainly derived from Yanshanian granitic magma,the evolution of which resulted in highly differentiated melt,as recorded by melt and melt-fluid inclusions in pegmatoid quartz,and high concentrations of metals in the fluids.Cooling of the ore-forming fluids and mixing with meteoric water may be the key factors that led to mineralization in the Dahutang tungsten polymetallic ore field.展开更多
Lucerne （Medicago sativa L.） is a deep-rooted perennial leguminous forage with high evapo-transpiration rate exceeding the annual precipitation in semi-arid areas of Northwest China. Groundwater might be the potenti...Lucerne （Medicago sativa L.） is a deep-rooted perennial leguminous forage with high evapo-transpiration rate exceeding the annual precipitation in semi-arid areas of Northwest China. Groundwater might be the potential water sources of lucerne in the area with shallow groundwater table. In this study, stable isotopic compositions of oxygen and hydrogen （6180 and 8D） of different water sources and xylem sap were analyzed to determine the seasonal （April, June, July and August） and topographic （three slope positions） variations in water sources for lucerne growing in Ningxia eastern semi-arid area adjacent to Mu Us Desert characterized by shallow groundwater table. IsoSource software was used to calculate the probable contribution of different water sources to the total plant water uptake. Stomatal conductance, stem water potential, carbon isotope discrimination （A13C） of whole plant were also determined for evaluating the water status of lucerne growing at different slope positions. The results showed that soil water content increased as the elevation decreased. Oxygen compositions of soil water in the 0-40 cm profile fluctuated considerably. Soil water 8180 values in deep profile （〉3.5 m） were similar to those in groundwater, implying the recharge of groundwater to this soil layer. Highest water utilization rate from deep soil profile （below 350 cm） was recorded for lucerne grown at the slope position 1 （groundwater table depth of 3.5-3.9 m） in April, June and July. The lucernes at slope position 2 （groundwater table depth of 5.8-6.4 m） and slope position 3 （groundwater table depth 7.1-8.3 m） mostly used water from deep soil layers （below 350 cm） during dry period, and turned to use water from superficial soil layer in wet period. Higher yield, A13C value of whole plant and stomatal conductance were observed for lucerne grown at the slope position 1 than those at other slope positions. These results indicated that groundwater is a significant water source for transpiration of lucerne grown in Ningxia semi-arid area with shallow groundwater table where lucerne grassland is suggested to be established so as to obtain better yield performance.展开更多
Stable hydrogen and oxygen isotope has important implication on water and mois- ture transportation tracing research. Based on stable hydrogen （6D） and oxygen （6180） isotope using a Picarro Ll102-i and water chemi...Stable hydrogen and oxygen isotope has important implication on water and mois- ture transportation tracing research. Based on stable hydrogen （6D） and oxygen （6180） isotope using a Picarro Ll102-i and water chemistry （e.g. major ions, pH, EC and TDS） meas- urement, this study discussed the temporal variation and characteristics of stable hydrogen and oxygen isotope, chemistry （e.g. TDS, pH, EC, Ca^2^, Mg2＋, Na^＋ and CI） in various water bodies including glacier meltwater runoff, ice and snow, and precipitation at the Laohugou g^acier basin during June 2012 to September 2013. Results showed that 6D and δ18O in the meltwater runoff varied obviously with the temporal change from June to September, showing firstly increasing trend and then decreasing trend, with the highest values in July with high air temperature and strong glacier melting, which could indicate the temporal change of glacier melting process and extent. Variations of 6D and δ18O in the runoff were similar with that of snow and ice on the glacier, and the values were also above the GMWL, which probably im- plied that the glacier runoff was mainly originated from glacier melting and precipitation supply The glacier meltwater chemical type at the Laohugou glacier basin were mainly composed by Ca-Na-HCO3-SO4 and Ca-Mg-HCO3-SO4, which also varied evidently with the glacier melting process in summer. By analyzing the temporal change of stable hydrogen and oxygen isotope and chemistry in the melting period, we find it is easy to separate the components of the snow and ice, atmospheric precipitation and melt-runoff in the river, which could reflect the change process of glacier melting during the melting period, and thus this work can contribute to the glacier runoff change study of large-scale region by stable isotope and geochemical method in future.展开更多
基金supported by the National Natural Science Foundation of China(50979065,51109154 and 51249002)the Natural Science Foundation of Shanxi Province,China(2012021026-2)+2 种基金the Program for Science and Technology Development of Shanxi Province,China(20110311018-1)the Specialized Research Fund for the Doctoral Program of Higher Education,China(20111402120006,20121402110009)the Program for Graduate Student Education and Innovation of Shanxi Province,China(2015BY27)
文摘Crop root system plays an important role in the water cycle of the soil-plant-atmosphere continuum. In this study, com- bined isotope techniques, root length density and root cell activity analysis were used to investigate the root water uptake mechanisms of winter wheat （Triticum aesfivum L.） under different irrigation depths in the North China Plain. Both direct inference approach and multisource linear mixing model were applied to estimate the distribution of water uptake with depth in six growing stages. Results showed that winter wheat under land surface irrigation treatment （Ts） mainly absorbed water from 10-20 cm soil layers in the wintering and green stages （66.9 and 72.0%, respectively）; 0-20 cm （57.0%） in the jointing stage; 0-40 （15.3%） and 80-180 cm （58.1%） in the heading stage; 60-80 （13.2%） and 180-220 cm （35.5%） in the filling stage; and 0-40 （46.8%） and 80-100 cm （31.0%） in the ripening stage. Winter wheat under whole soil layers irrigation treatment （Tw） absorbed more water from deep soil layer than Ts in heading, filling and ripening stages. Moreover, root cell activity and root length density of winter wheat under TW were significantly greater than that of Ts in the three stages. We concluded that distribution of water uptake with depth was affected by the availability of water sources, the root length density and root cell activity. Implementation of the whole soil layers irrigation method can affect root system distribution and thereby increase water use from deeper soil and enhance water use efficiency.
基金supported by the China Geological Survey and International Atomic Energy Agency.
文摘Hundreds of precipitation samples collected from meteorological stations in the Ordos Basin from January 1988 to December 2005 were used to set up a local meteoric water line and to calculate weighted average isotopic compositions of modern precipitation. Oxygen and hydrogen isotopes, with averages of-7.8‰ and -53.0‰ for δ^18O and δD, respectively, are depleted in winter and rich in spring, and gradually decrease in summer and fall, illustrating that the seasonal effect is considerable. They also show that the isotopic difference between south portion and north portion of the Ordos Basin are not obvious, and the isotope in the middle portion is normally depleted. The isotope compositions of 32 samples collected from shallow groundwater （less than a depth of 150 m） in desert plateau range from -10.6‰ to -6.0‰ with an average of-8.4‰ for δ^18O and from -85‰ to -46‰ with an average of-63‰ for δD. Most of them are identical with modern precipitation. The isotope compositions of 22 middle and deep groundwaters （greater than a depth of 275 m） fall in ranges from -11.6‰ to -8.8‰ with an average of -10.2‰ for δ^18O and from -89‰ to -63‰ with an average of -76‰ for δD. The average values are significantly less than those of modern precipitation, illustrating that the middle and deep groundwaters were recharged at comparatively lower air temperatures. Primary analysis of ^14C shows that the recharge of the middle and deep groundwaters started at late Pleistocene. The isotopes of 13 lake water samples collected from eight lakes define a local evaporation trend, with a relatively flat slope of 3.77, and show that the lake waters were mainly fed by modern precipitation and shallow groundwater.
基金financially supported by the China Geological Survey (No. 1212011220014)。
文摘According to the hydrochemical characteristics, hydrogen and oxygen isotope characteristics and the ratio of noble gas isotopes of the sandstone aquifer and basalt aquifer, this study calculated the recharge temperature and residence time of groundwater in the Weishan area of Wudalianchi, also calculating the contribution of noble gas components from different sources to the samples. Based on the characteristics of hydrogen and oxygen isotopes and noble gases Xe and Ne, the recharge altitude and recharge temperature of the two aquifers were estimated, and the recharge temperature fitting with the NGT model as verified, the results showing that the main recharge altitude of groundwater in the region was 500–600 m, the recharge temperature being 2–7°C. He_(eq) and He_(ea) of the samples have been simulated using the OD model, the content of radioactive ~4He in the crust being obtained, the groundwater ages under the two conditions(closed condition and open condition) both being simulated. The results show that groundwater from the sandstone layer water is older than groundwater from the basalt layer. Hydrochemical characteristics and noble gas isotope ratios indicate that in the basalt aquifer and sandstone aquifer in the Weishan area, in addition to atmospheric and crustal helium, there is also an input of mantle-derived helium. The fault constitutes the uplift channel for groundwater containings mantle components, which results in the mantle source composition in water samples near the fault being much higher than those form non-fault areas.
基金jointly supported by the Geological Survey of China (Grant No. 1212011140050)the National Natural Science Foundation of China (Grant No. 41663006)
文摘The Badi copper deposit is located in Shangjiang town, Shangri-La County, Yunnan Province. Tectonically, it belongs to the Sanjiang Block. Vapor-liquid two-phase fluid inclusions, CO2-bearing fluid inclusions, and daugh- ter-beating inclusions were identified in sulfide-rich quartz veins. Microthermometric and Raman spectroscopy studies revealed their types of ore-forming fluids： （1） low-tem- perature, low-salinity fluid; （2） medium-temperature, low salinity CO2-bearing; and （3） high-temperature, Fe-rich, high sulfur fugacity. The δ^18O values of chalcopyrite- bearing quartz ranged from 4.96‰ to 5.86%0, with an average of 5.40%0. The δD values of ore-forming fluid in equilibrium with the sulfide-bearing quartz were from - 87‰ to - 107‰, with an average of - 97.86%0. These isotopic features indicate that the ore-forming fluid is a mixing fluid between magmatic fluid and meteoric water. The δ^34S values of chalcopyrite ranged from 13.3‰ to 15.5‰, with an average of 14.3‰. Sulfur isotope values suggest that the sulfur in the deposit most likely derived from seawater. Various fluid inclusions coexisted in the samples; similar homogenization temperature to different phases suggests that the Badi fluid inclusions might have been captured under a boiling system. Fluid boiling caused by fault activity could be the main reason for the mineral precipitation in the Badi deposit.
文摘The Ordovician was an important transitional period for global climate and organic evolution,the global was in the flood and glacial,Onganism was extinction(Zhan,2007;Trotter et al.,2008;Axel et al.,2010).Under the influence
基金funded by the National Natural Science Foundation of China(NSFC)(Grant Nos.41225020 and41376049)National Programme on Global Change and Air-Sea Interaction(GASI-GEOGE-03)
文摘Recent studies suggest that the hydrogen and oxygen isotopic compositions of clay minerals can indicate paleoclimate.Here,we report mineralogy and stable isotopic records(d D and δ^(18)O_(OH))of a weathering profile located in the Fujian Province,aiming to validate whether hydroxyl stable isotopes can indicate paleo-precipitation and paleo-temperature.Our results indicate that the d D and δ^(18)O_(OH)changes in the kaolinite hydroxyl of the weathering profile are basically determined by the isotopic composition of paleo-meteoric water and paleotemperature,respectively.Nevertheless,whether the d D and δ^(18)O_(OH)of kaolinite can quantitatively indicate paleo-precipitation and paleo-temperature needs to be verified further,and especially,the structural oxygen isotopic composition that is the essential element for the kaolinite formation temperature calculation has to be constrained in future work.
基金support from several sources,including the Backbone Teacher Training Program(10912-SJGG2021-04233)the Teaching Reform Project of Chengdu University of Technology(JG2130131)+1 种基金the University-Industry Collaborative Education Project,Ministry of Education,China(22097130210756)National Natural Science Foundation of China(42272129).
文摘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.
基金provided by a grant from Chuck Baltzer,Environmental Support Servicesgraciously awarded by Grand Canyon National Park officials
文摘New oxygen and hydrogen isotope ratios of chert from middle, intraformational breccias, and upper breccia members of the Sixtymile Formation（SMF） in eastern Grand Canyon National Park（AZ） yield palaeoclimate estimates between 27 and 33℃. The isotopic compositions of cherts define a domain approximately parallel to the meteoric water line when plotted on a δD–δ-（18）O diagram; these data indicate that meteoric water was involved during formation of the chert. In thin section, the absence of interlocking mega quartz（〉35 lm） and silicafilled fractures and veins, along with preserved micromorphological silica fabrics, suggest that the chert has not been permeated by later hydrothermal fluids. Petrographic observations in thin section such as cyclic silica precipitation phases and glaebular micromorphologic fabrics lend support to the interpretation that meteoric waters were involved during chert precipitation. The post 742 Ma SMF has been correlated with diamictite（transition） beds of the Kingston Peak Formation（CA）, which in turn have been interpreted to have been deposited during the Sturtian Ice Age（-750–700 Ma）. Absence of facetted and striated clasts and other diagnostic glaciogenic features in the SMF,an unconformable contact with the stratigraphically older Chuar Group, coupled with warm palaeotemperature data inferred from stable isotope values of chert, tentatively suggest that deposition of sediment in the SMF likely did not take place during the Sturtian Ice Age.
基金The National Major Science and Technology Program for Water Pollution Control and Treatment,No.2017ZX07101001-02。
文摘Despite the increasing depletion of the groundwater at the Zhangjiakou aquifer system in the northwest of Beijing-Tianjin-Hebei region,little information is available on the hydrological process of groundwater in this region.In this study,we utilized water isotopes composition(51sO,5D and 3H)of groundwater,river and precipitation to identify the characteristics of hydrochemistry,groundwater age and recharge rates in different watersheds of the Zhangjiakou area.Results showed that the river water and groundwater could be characterized as HCO3-Mg Na,HCO3 CI-Na and HCO3-Mg Na,HCO3 CI-Na,HCO3 CI-Na Mg types,respectively.The 5D and 5180 values in precipitation were linearly correlated,which is similar to the Global Meteorological Water Line(GMWL).Furthermore,the decreasing values of the 6D and 5180 from precipitation to surface water and groundwater indicate that groundwater is mainly recharged by atmospheric precipitation.In addition,the variation of 3H concentration with depth suggests that groundwater shallower than around 100 m is generally modern water.In contrast,groundwater deeper around 100 m is a mixture of modern and old waters,which has longer residence times.Groundwater showed a relatively low tritium concentration in the confined aquifers,indicating the groundwater recharged might be relatively old groundwater of over 60 years.The flow velocity of the groundwater in the study area varied from 1.10 to 2.26 m/a,and the recharge rates ranged from 0.034 to 0.203 m/a.The obtained findings provide important insights into understanding the groundwater recharge sources and hydrochemistry in the Zhangjiakou area,in turn developing a sustainable groundwater management plan.
基金supported by theNational Key Research and Development Program(No.2018YFC0603806)the Geological Surveying Project of China Geological Survey(No.DD20190166).
文摘The Baiyun deposit is a large gold deposit at the western end of the Liaoji rift zone in Liaoning Province, which has produced both auriferous quartz-vein type and altered-rock type mineralization. The ore bodies are mainly hosted in schist from the Gaixian Formation of the Liaohe Group. A detailed field geological survey showed that the quartz-vein type gold ore bodies are distributed in the near EW-trending and occur in the extensional tectonic space of schist in the Gaixian Formation, and the altered-rock type gold ore bodies are distributed in the near EW-trending structural belt and occur near in the Gaixian Formation of biotite schist, biotite granulite, marble and the upper footwall of dike. To further elucidate the source of ore-forming fluid and material in the Baiyun gold deposit, the H-O isotopes for quartz, S and Pb isotopes, in-situ trace elements for sulfides from quartz-vein and altered-rock type mineralization were studied. The H-O isotopic δD_(V-SMOW) and δ^(18)O_(H2O) values of the auriferous quartz range were from-88.8‰ to-82.2‰ and-1.95‰ to 4.85‰, respectively, suggests that the ore-forming fluids were mainly magmatic water with minor meteoric water. The distribution ranges of in-situ S isotopic compositions of Au-bearing pyrite in the quartz-vein type and altered-rock type ores were-8.38‰–-10.47‰(with average values of-7.89‰) and 11.38‰– 17.52‰(with average values of 11.55‰), respectively, indicating that the S isotopic compositions of the two ore types were clearly different. The in-situ Pb isotopic ratios changed almost uniformly, which showed that they had the same lead isotopic source. Based on the analysis of S and Pb isotopic compositions, the metallogenic materials in the Baiyun gold deposit were primarily from deep magma, and some wall rock materials may have been mixed in the metallogenic process. Co/Ni diagram shows that most Au-bearing pyrites have magmatic-hydrothermal or sedimentary alteration properties, and Au/As ratios were between 0.001 and 0.828(the average value was 0.07), indicating that the ore-forming fluid in the Baiyun gold deposit may have been deep magma. Combining the geological, trace element, and isotopic data, as well as data from previous studies, we propose that the Baiyun gold deposit is a magmatic-hydrothermal ore deposit.
基金financially supported by the National Natural Science Foundation of China(NFSC No.41573039)
文摘The Ciemas gold deposit is located in West Java of Indonesia,which is a Cenozoic magmatism belt resulting from the Indo-Australian plate subducting under the Eurasian plate.Two different volcanic rock belts and associated epithermal deposits are distributed in West Java:the younger late Miocene-Pliocene magmatic belt generated the Pliocene-Pleistocene epithermal deposits,while the older late Eocene-early Miocene magmatic belt generated the Miocene epithermal deposits.To constrain the physico-chemical conditions and the origin of the ore fluid in Ciemas,a detailed study of ore petrography,fluid inclusions,laser Raman spectroscopy,oxygen-hydrogen isotopes for quartz was conducted.The results show that hydrothermal pyrite and quartz are widespread,hydrothermal alteration is well developed,and that leaching structures such as vuggy rocks and extension structures such as comb quartz are common.Fluid inclusions in quartz are mainly liquid-rich two phase inclusions,with fluid compositions in the NaCl-H_(2)O fluid system,and contain no or little CO_(2).Their homogenization temperatures cluster around 240℃-320℃,the salinities lie in the range of 14-17 wt.%NaCl equiv,and the calculated fluid densities are 0.65-1.00 g/cm^3.The values ofδ18OH2O-VSMOW for quartz range from+5.5%0 to+7.7‰,theδDVSMOW of fluid inclusions in quartz ranges from-70‰to-115‰.All of these data indicate that mixing of magmatic fluid with meteoric water resulted in the formation of the Ciemas deposit.A comparison among gold deposits of West Java suggests that Miocene epithermal ore deposits in the southernmost part of West Java were more affected by magmatic fluids and exhibit a higher degree of sulfidation than those of Pliocene-Pleistocene.
基金funded by the National Natural Science Foundation of China(41730854,41877157,42177236)。
文摘Studying spatial and temporal characteristics of regional groundwater recharge will guide the scientific management and sustainable development of regional water resources.This study investigated stable isotopes(δ^(18)O andδ^(2)H)of precipitation,groundwater,river water and lake water during 2019-2020 in Qinghai Lake Basin to reveal the spatial and temporal characteristics of groundwater recharge.The local meteoric water line was simulated using ordinary least squares regression(δ^(2)H=7.80δ^(18)O+10.60).The local evaporation lines of the river water,lake water and groundwater were simulated asδ^(2)H=6.21δ^(18)O-0.72,δ^(2)H=5.73δ0-3.60 andδ^(2)H=6.59δ0+1.76,respectively.Theδ^(2)H andδ^(18)O of river water and groundwater were in more depleted values due to the recharge by precipitation at high altitudes or precipitation effects,and theδ^(2)H andδ^(18)O of the lake water were in more enriched values because of evaporation.The relationship between theδ^(2)H andδ^(18)O of groundwater and river water was not significantly different,indicating a strong hydrological connection between the groundwater and river water surrounding Qinghai Lake.Additionally,the maximum values ofδ^(18)O and the minimum values of lc-excess of groundwater in most regions were both in August,and the minimum values ofδ^(18)O and the maximum values of lc-excess of groundwater in most regions were both in October.Therefore,the groundwater was recharged by soil water with strong evaporation in August and recharged by precipitation at high altitudes in October.The recharge rate of groundwater was relatively fast in areas with large slopes and large hydraulic gradients(e.g.,south of Qinghai Lake),and in areas with strong hydrological connections between the groundwater and river water(e.g.,the Buha River Valley).Those results can provide data support for protection and utilization of water resources in Qinghai Lake Basin,and provide reference for groundwater research in closed lake basins on the Qinghai-Tibet Plateau.
基金Under the auspices of Major Science and Technology Program for Water Pollution Control and Treatment(No.2012ZX07201004)National Natural Science Foundation of China(No.41101470)
文摘In order to investigate the transformation among the precipitation,groundwater,and surface water in the Sanjiang Plain,Northeast China,precipitation and groundwater samples which were collected at the meteorological station of the Sanjiang Mire Wetland Experimental Station,Chinese Academy of Sciences and the surface water which collected from the Wolulan River were used to identify the transformation of three types of water.The isotope composition of different kinds of water sources were analyzed via stable isotope(deuterium and oxygen-18) investigation of natural water.The results show a clear seasonal difference in the stable isotopes in precipitation.During the cold half-year,the mean stable isotope in precipitation in the Sanjiang Plain reaches its minimum with the minimum temperature.The δ18O and δD values are high in the rainy season.In the Wolulan River,the evaporation is the highest in August and September.The volume of evaporation and the replenishment to the river is mostly same.The groundwater is recharged more by the direct infiltration of precipitation than by the river flow.The results of this study indicate that the water bodies in the Sanjiang Plain have close hydrologic relationships,and that the transformation among each water system frequently occurs.
文摘Located in Alxa Zuoqi (Left Banner) of Inner Mongolia, China, the Zhulazhaga gold deposit is the first large- scale gold deposit that was found in the middle-upper Proterozoic strata along the north margin of the North China craton in recent years. It was discovered by the No. 1 Geophysical and Geochemical Exploration Party of Inner Mongolia as a result of prospecting a geochemical anomaly. By now, over 50 tonnes of gold has been defined, with an average Au grade of 4 g/ t. The ore bodies occur in the first lithological unit of the Mesoproterozoic Zhulazhagamaodao Formation (MZF), which is composed mainly of epimetamorphic sandstone and siltstone and partly of volcanic rocks. With high concentration of gold, the first lithological unit of the MZF became the source bed for the late-stage ore formation. Controlled by the interstratal fracture zones, the ore bodies mostly appear along the bedding with occurrence similar to that of the strata. The primitive ore types are predominantly the altered rock type with minor ore belonging to the quartz veins type. There are also some oxidized ore near the surface. The metallic minerals are composed mainly of pyrite, pyrrhotite and arsenopyrite with minor chalcopyrite, galena and limonite. Most gold minerals appear as native gold and electrum. Hydrothermal alterations associated with the ore formation are actinolitization, silicatization, sulfidation and carbonation. A total of 100 two-phase H 2 O-rich and 7 three-phase daughter crystal-bearing inclusions were measured in seven gold- bearing quartz samples from the Zhulazhaga gold deposit. The homogenization temperatures of the two-phase H 2 O-rich inclusions range from 155 to 401°C, with an average temperature of 284°C and bimodal distributions from 240 to 260°C and 300 to 320°C respectively. The salinities of the two-phase H 2 O-rich inclusions vary from 9.22wt% to 24.30wt% NaCl equiv, with a mode between 23 wt% and 24wt% NaCl equiv. Comparatively, the homogenization temperatures of the three- phase daughter crystal-bearing inclusions vary from 210 to 435°C and the salinities from 29.13wt% to 32.62wt% NaCl equiv. It indicates that the ore-forming fluid is meso-hypothermal and characterized by high salinity, which is apparently different from the metamorphic origin with low salinity. It suggests a magmatic origin of the gold-bearing fluid. The δ 18 O values of quartz from auriferous veins range from 11.9 to 16.3 per mil, and the calculated values in equilibrium with quartz vary from 1.06 to 9.60 per mil, which fall between the values of meteoric water and magmatic water. It reflects that the ore-forming fluid may be the product of mixing of meteoric water and magmatic water. Based on geological and geochemical studies of the Zhulazhaga gold deposit, it is supposed that the volcanism in the Mesoproterozoic might make gold pre-concentrate in the strata. The extensive and intensive Hercynian tectono-magmatic activity not only brought along a large number of ore-forming materials, but also made the gold from the strata rework. It can be concluded that the ore bodies were mainly formed in late hydrothermal reworking stage. Compared with typical gold deposits associated with epimetamorphic clastic rocks, the Zhulazhaga deposit has similar features in occurrence of ore bodies, ore-controlling structure, wall-rock alterations and mineral assemblages. Therefore, the Zhulazhaga gold deposit belongs to the epimetamorphic clastic rock type.
文摘The Qaidam Basin is a large intermontane depression in Qinghai Province,China,which located on the northern margin of the Tibet plateau,and surrounded by the Qilian,Kunlun and Aljun mountains which rise to more than 5000m.Some 27 salt lakes occur within the basin,occupying an area of approximately 1500 km2.Additionally,there are extensive areas of dry playas.Together,the playas and salt lakes cover about one quarter of the total basin area.Whereas the western
基金This study was supported by the National Natural Science Foundation of China (Grant No.41902065, 41772197)Open Reserch Fund from the State Key Laboratory Breeding base of Nuclear Resources and environment (Grant NRE1803)+1 种基金the Chongqing Science and Technology Innovation Project (Zhu Zhengjie)the Major State Basic Research Development Program (No.2011CB40300)
文摘Sichuan Basin is one of the most important marine–salt forming basins in China. The Simian and Triassic have a large number of evaporites. The Triassic strata have found a large amount of polyhalite and potassium-rich brine. However, no soluble potassium salt deposit were found. In this study, the halite in well Changping 3 which is located at the eastern part of the Sichuan basin was studied using the characteristics, hydrogen and oxygen isotopes of the fluid inclusion in halite to reconstruct the paleoenvironment. The salt rocks in well Changping 3 can be divided into two types: grey salt rock and orange salt rock. The result shows that the isotopic composition of the halite fluid inclusion is distinct from the global precipitation line reflecting that the salt formation process is under strong evaporation conditions and the climate is extremely dry. At the same time, compared with the hydrogen and oxygen isotopes of brine in the Sichuan Basin and the hydrous isotope composition of the inclusions in the salt inclusions of other areas in China, it is shown that the evaporation depth of the ancient seawater in the Sichuan Basin was high and reached the precipitation of potassium and magnesium stage.
基金supported by the National Natural Science Foundation of China (Grant No. 50679024)the Innovation Program for College Graduate of Jiangsu Province of 2007 (Grant No. CX07B_130Z)
文摘The variation of stable isotope ratios in natural waters provides valuable information that can be used to trace water movement. Evaporation plays a crucial role in determining the variation of stable isotopes. In this paper, several evaporation experiments were conducted in order to study the stable isotopic fractionation mechanism of water and analyze the influence of different temperatures on evaporation fractionation. Three group experiments of water evaporation under different temperatures and initial isotopic values were carried out. The results show that fractionation factors of hydrogen and oxygen may increase with temperature, and the average enrichment degree of hydrogen isotope D is 3.432 times that of oxygen isotope 18O. The results also show that the isotopic composition of the initial water has little influence on water evaporation fractionation, which is mainly affected by the state variables in the evaporation process, such as temperature. This research provides experimental data for further understanding the evaporation fractionation mechanism.
基金supported by the Old Mine Prospecting Technology Innovation and Demonstration Projects of China Geological Survey(No.1212011220737)
文摘The Dahutang tungsten polymetallic ore field is located north of the Nanling W-Sn polymetallic metallogenic belt and south of the Middle—Lower Yangtze River Valley Cu-Mo-Au-Fe porphyry-skarn belt.It is a newly discovered ore field,and probably represents the largest tungsten mineralization district in the world.The Shimensi deposit is one of the mineral deposits in the Dahutang ore field,and is associated with Yanshanian granites intruding into a Neoproterozoic granodiorite batholith.On the basis of geologic studies,this paper presents new petrographic,microthermometric,laser Raman spectroscopic and hydrogen and oxygen isotopic studies of fluid inclusions from the Shimensi deposit.The results show that there are three types of fluid inclusions in quartz from various mineralization stages：liquid-rich two-phase fluid inclusions,vapor-rich two-phase fluid inclusions,and three-phase fluid inclusions containing a solid crystal,with the vast majority being liquid-rich two-phase fluid inclusions.In addition,melt and melt-fluid inclusions were also found in quartz from pegmatoid bodies in the margin of the Yanshanian intrusion.The homogenization temperatures of liquid-rich two-phase fluid inclusions in quartz range from 162 to 363℃ and salinities are 0.5wt%-9.5wt%NaCI equivalent.From the early to late mineralization stages,with the decreasing of the homogenization temperature,the salinity also shows a decreasing trend.The ore-forming fluids can be approximated by a NaCl-H_2O fluid system,with small amounts of volatile components including CO_2,CH_4 and N_2,as suggested by Laser Raman spectroscopic analyses.The hydrogen and oxygen isotope data show that δ5D_（V-smow） values of bulk fluid inclusions in quartz from various mineralization stages vary from-63.8‰ to-108.4‰,and the δ^（18）O_（H2O） values calculated from the δ^（18）O_（V-）smow values of quartz vary from-2.28‰ to 7.21‰.These H-O isotopic data are interpreted to indicate that the ore-forming fluids are mainly composed of magmatic water in the early stage,and meteoric water was added and participated in mineralization in the late stage.Integrating the geological characteristics and analytical data,we propose that the ore-forming fluids of the Shimensi deposit were mainly derived from Yanshanian granitic magma,the evolution of which resulted in highly differentiated melt,as recorded by melt and melt-fluid inclusions in pegmatoid quartz,and high concentrations of metals in the fluids.Cooling of the ore-forming fluids and mixing with meteoric water may be the key factors that led to mineralization in the Dahutang tungsten polymetallic ore field.
基金funded by the National Natural Science Foundation of China(31160478)the National Program on Key Basic Research Project of China(2012CB723206)the Agricultural Breeding Project of Ningxia Hui Autonomous Region(2014NYYZ0401)
文摘Lucerne （Medicago sativa L.） is a deep-rooted perennial leguminous forage with high evapo-transpiration rate exceeding the annual precipitation in semi-arid areas of Northwest China. Groundwater might be the potential water sources of lucerne in the area with shallow groundwater table. In this study, stable isotopic compositions of oxygen and hydrogen （6180 and 8D） of different water sources and xylem sap were analyzed to determine the seasonal （April, June, July and August） and topographic （three slope positions） variations in water sources for lucerne growing in Ningxia eastern semi-arid area adjacent to Mu Us Desert characterized by shallow groundwater table. IsoSource software was used to calculate the probable contribution of different water sources to the total plant water uptake. Stomatal conductance, stem water potential, carbon isotope discrimination （A13C） of whole plant were also determined for evaluating the water status of lucerne growing at different slope positions. The results showed that soil water content increased as the elevation decreased. Oxygen compositions of soil water in the 0-40 cm profile fluctuated considerably. Soil water 8180 values in deep profile （〉3.5 m） were similar to those in groundwater, implying the recharge of groundwater to this soil layer. Highest water utilization rate from deep soil profile （below 350 cm） was recorded for lucerne grown at the slope position 1 （groundwater table depth of 3.5-3.9 m） in April, June and July. The lucernes at slope position 2 （groundwater table depth of 5.8-6.4 m） and slope position 3 （groundwater table depth 7.1-8.3 m） mostly used water from deep soil layers （below 350 cm） during dry period, and turned to use water from superficial soil layer in wet period. Higher yield, A13C value of whole plant and stomatal conductance were observed for lucerne grown at the slope position 1 than those at other slope positions. These results indicated that groundwater is a significant water source for transpiration of lucerne grown in Ningxia semi-arid area with shallow groundwater table where lucerne grassland is suggested to be established so as to obtain better yield performance.
基金National Natural Science Foundation of China,No.41301065The West Light Program for Talent Cultivation of Chinese Academy of Sciences
文摘Stable hydrogen and oxygen isotope has important implication on water and mois- ture transportation tracing research. Based on stable hydrogen （6D） and oxygen （6180） isotope using a Picarro Ll102-i and water chemistry （e.g. major ions, pH, EC and TDS） meas- urement, this study discussed the temporal variation and characteristics of stable hydrogen and oxygen isotope, chemistry （e.g. TDS, pH, EC, Ca^2^, Mg2＋, Na^＋ and CI） in various water bodies including glacier meltwater runoff, ice and snow, and precipitation at the Laohugou g^acier basin during June 2012 to September 2013. Results showed that 6D and δ18O in the meltwater runoff varied obviously with the temporal change from June to September, showing firstly increasing trend and then decreasing trend, with the highest values in July with high air temperature and strong glacier melting, which could indicate the temporal change of glacier melting process and extent. Variations of 6D and δ18O in the runoff were similar with that of snow and ice on the glacier, and the values were also above the GMWL, which probably im- plied that the glacier runoff was mainly originated from glacier melting and precipitation supply The glacier meltwater chemical type at the Laohugou glacier basin were mainly composed by Ca-Na-HCO3-SO4 and Ca-Mg-HCO3-SO4, which also varied evidently with the glacier melting process in summer. By analyzing the temporal change of stable hydrogen and oxygen isotope and chemistry in the melting period, we find it is easy to separate the components of the snow and ice, atmospheric precipitation and melt-runoff in the river, which could reflect the change process of glacier melting during the melting period, and thus this work can contribute to the glacier runoff change study of large-scale region by stable isotope and geochemical method in future.
