A reasonable classification of deposits holds great significance for identifying prospecting targets and deploying exploration. The world ’s keen demand for lithium resources has expedited the discovery of numerous n...A reasonable classification of deposits holds great significance for identifying prospecting targets and deploying exploration. The world ’s keen demand for lithium resources has expedited the discovery of numerous novel lithium resources. Given the presence of varied classification criteria for lithium resources presently, this study further ascertained and classified the lithium resources according to their occurrence modes, obtaining 10 types and 5 subtypes of lithium deposits(resources) based on endogenetic and exogenetic factors. As indicated by surveys of Cenozoic exogenetic lithium deposits in China and abroad,the formation and distribution of the deposits are primarily determined by plate collision zones, their primary material sources are linked to the anatectic magmas in the deep oceanic crust, and they were formed primarily during the Miocene and Late Paleogene. The researchers ascertained that these deposits,especially those of the salt lake, geothermal, and volcanic deposit types, are formed by unique slightly acidic magmas, tend to migrate and accumulate toward low-lying areas, and display supernormal enrichment. However, the material sources of lithium deposits(resources) of the Neopaleozoic clay subtype and the deep brine type are yet to be further identified. Given the various types and complex origins of lithium deposits(resources), which were formed due to the interactions of multiple spheres, it is recommended that the mineralization of exogenetic lithium deposits(resources) be investigated by integrating tectono-geochemistry, paleoatmospheric circulation, and salinology. So far, industrialized lithium extraction is primarily achieved in lithium deposits of the salt lake, clay, and hard rock types. The lithium extraction employs different processes, with lithium extraction from salt lake-type lithium deposits proving the most energy-saving and cost-effective.展开更多
1 Introduction The Laurani porphyry deposit is located in the Altiplano,an extensive North-South trending structural basin that formed in Central-Andean metallogenic belt,Bolivia.The Altiplano poly-metallic province c...1 Introduction The Laurani porphyry deposit is located in the Altiplano,an extensive North-South trending structural basin that formed in Central-Andean metallogenic belt,Bolivia.The Altiplano poly-metallic province contains sub-volcanic ore展开更多
On the basis of the studies of field geology, strontium, hydrogen and oxygen isotopes and REEgeochemistry, coupled with the dating of mineralization, the authors suggest a minerogenetic model of circula-tion and drawi...On the basis of the studies of field geology, strontium, hydrogen and oxygen isotopes and REEgeochemistry, coupled with the dating of mineralization, the authors suggest a minerogenetic model of circula-tion and drawing of Late Cretaceous geothermal waters for the fluorite deposits in southeastern China. Thismodel includes two types of mechanism: 1) the leaching-out and drawing through deep circulation of thegeothermal water, and 2) the leaching-out and drawing through shallow circulation of the water. The fluoritemineralization of Mesozoic volcanic rock terrain is related mainly to the former mechanism, with the mineraliz-ing material coming chiefly from the Precambrian metamorphic rocks of the basement underlying the hostrocks; while that of Yanshanian granite terrain is associated with the latter mechanism, with the mineralizingmaterial derived primarily from the host granites and sedimentary rocks.展开更多
The Phlaythong large iron deposit in Shampasak of southern Laos,is located in the Kon Tum microblock （Fig.1A）,central-southern part of the Indo-China block,and the geographic coordinate of the central mining area is...The Phlaythong large iron deposit in Shampasak of southern Laos,is located in the Kon Tum microblock （Fig.1A）,central-southern part of the Indo-China block,and the geographic coordinate of the central mining area is 14°43′04″ N and 106°07′02″ E.展开更多
China has widely distributed silver deposits,and is rich in silver resources.Although silver deposits are mainly associated with Pb-Zn deposits,a number of independent silver deposits have also been discovered in rece...China has widely distributed silver deposits,and is rich in silver resources.Although silver deposits are mainly associated with Pb-Zn deposits,a number of independent silver deposits have also been discovered in recent years.Silver deposits include different types,such as submarine volcanism and continental volcanism related type,intrusion related type,and sedimentary related type.This study summarized the metallogenic regularity of China＇s silver deposits systematically based mainly on the data from 490 silver deposits.It is shown that submarine volcanic sedimentary type,continental volcanic or sub-volcanic type,skarn type,hydrothermal type（including vein type and stratabound type）,sedimentary metamorphic type,sedimentary type and regolith type should be regarded as the most important prediction types of silver deposit.A total of 32 silver mineralization belts and 111 silver concentration areas have been delineated.The map of ＂Spatial distribution of silver mineralization belts in China＂ and other series of maps finished in this study may provide a theoretical basis for the evaluation and prognosis of silver resources potential in China.展开更多
Molybdenum is one of the dominant minerals in China because of its rich reserves.In recent years,outstanding breakthroughs have been made in molybdenum prospecting in China,and the distribution of molybdenum deposits ...Molybdenum is one of the dominant minerals in China because of its rich reserves.In recent years,outstanding breakthroughs have been made in molybdenum prospecting in China,and the distribution of molybdenum deposits in China is found to have a ＂planar pattern＂.In general,the molybdenum deposits are concentrated in eastern China,including the largest molybdenum reserves of Henan Province.In terms of the scale of molybdenum deposits,the identified resources of the superlarge deposits are the most important,which account for about 53% of the whole country,and those of the large deposits account for about 30%,those of the medium-sized deposits account for about 14%,those of the small-sized deposits,mine spots and mineralization account for about 3%.The molybdenum deposits are mainly classified as porphyry type,skarn type,hydrothermal（vein） type and sedimentary（metamorphic） type in genesis,and the identified resources of these types account for 85.75%,8.83%,2.79%and 2.63% of the total resources respectively.Based on the statistics of precise chronology data of molybdenites Re-Os,Mo-mineralization can be divided into 6 periods in Chinese geological history,which are Precambrian（〉800 Ma）,Cambrian-Silurian（540-415 Ma,Caledonian）,Devonian-Permian（400-290 Ma,Hecynian）,Triassic（260-200 Ma,Indosinian）,Jurassic-Cretaceous（195-70 Ma,Yanshanian） and Paleogene-Neogene（65-10 Ma,Himalayan）.Mo mineralization during the Yanshanian period is the strongest one,in which about 76.69% of the Chinese total identified resources was formed.The second is the Himalayan period.According to spatial-temporal distribution characteristics of molybdenum deposits,the metallogenic regularity of molybdenum deposits was preliminarily summarized,and 41 level-Ⅲ molybdenum-forming belts,13 level-Ⅱ molybdenum-forming provinces and 4 level-Ⅰ molybdenum-forming domains were ascertained in the mainland of China.There are 39 metallogenic series of and 60 sub-series of molybdenum deposits with molybdenum as the dominant metal and corresponding representative molybdenum deposits proposed.Metallogenic lineages of molybdenum deposits were also established.Spatial-temporal evolution of different types of molybdenum deposits,and the relationship between Mo-mineralization and tectonic evolution have been discussed in this paper.On this basis,the authors think that element Mo is an effective tracer for recording the crustal evolution history of China.At present,there are some problems in the exploration of Mo deposits in China,such as uneven exploration degrees in eastern and western China,shallow exploration depth,low and uneven grade,complex associated components,difficulty of mineral development and utilization,increasing costs of prospecting,and so on.According to successful experience of superficial and deep prospecting and considering also the discussion above,some suggestions are proposed for the prospecting of molybdenum deposits in the future.展开更多
Among the abundant aluminum ore resources in China, bauxite is dominated, which is mainly distributed in 19 provinces and regions, including Shanxi, Henan, Guizhou and Guangxi. The major deposit type of bauxite is pal...Among the abundant aluminum ore resources in China, bauxite is dominated, which is mainly distributed in 19 provinces and regions, including Shanxi, Henan, Guizhou and Guangxi. The major deposit type of bauxite is paleo-weathering crust sedimentary type, and the other one is the accumulation type. The main metallogenic period is the late Paleozoic Era followed by the Cenozoic Era. The metallogenic tectonic background is characterized by a cratonic environment. This paper summarizes the bauxite metallogenic regularity based on the characteristics of bauxite resources, bauxite deposit type, bauxite metallogenic belt and metallogenic series in China, and 15 bauxite metallogenic belts, 8 bauxite metallogenic series and 7 bauxite ore concentrated areas were identified in the study. This paper also provides a theoretical basis for the evaluation of the potential of bauxite resources.展开更多
This paper deals with the metallogenic model of the sandstone type uranium deposit in the northeastern Ordos Basin from aspects of uranium source, migration and deposition. A superposition metallogenic model has been ...This paper deals with the metallogenic model of the sandstone type uranium deposit in the northeastern Ordos Basin from aspects of uranium source, migration and deposition. A superposition metallogenic model has been established due to complex uranium mineralization processes with superposition of oil-gas reduction and thermal reformation.展开更多
Fluorite is one of the important mineral raw materials in the industry.In China,it is mainly distributed in the provinces and regions such as Hunan,Zhejiang,Jiangxi,Inner Mongolia,Fujian,and Henan provinces,boasting h...Fluorite is one of the important mineral raw materials in the industry.In China,it is mainly distributed in the provinces and regions such as Hunan,Zhejiang,Jiangxi,Inner Mongolia,Fujian,and Henan provinces,boasting huge reserves and large numbers of deposits.However,most of the fluorite deposits are on a small or medium scale.The main fluorite deposits in China were studied in this paper.Their geological features and metallogenic regularity were summarized and compared.Meanwhile,based on their main genetic factors including metallogenic fluid sources and main metallogenic geological processes,they were divided into two groups,namely meso-epithermal deposits and magmatic-hydrothermal deposits.Furthermore,based on the prospecting achievements and research progress obtained in fluorite deposits in recent years,prospecting potential predictions were made for the metallogenic prospect areas and major prospecting areas of fluorite in China.This aims to provide a theoretical basis and direction for future fluorite prospecting in China.展开更多
China is rich in abundant lithium resources characterized by considerable reserves and a concentrated distribution of metallogenic zones or belts,with proven reserves of 4046.8×10^(3) t(calculated based on Li_(2)...China is rich in abundant lithium resources characterized by considerable reserves and a concentrated distribution of metallogenic zones or belts,with proven reserves of 4046.8×10^(3) t(calculated based on Li_(2)O)by 2021.China is also a big consumer of lithium.By 2019,China’s lithium consumption in the battery sector alone had reached 99×10^(3) t,with an average annual growth rate of nearly 26%.China has become the world’s largest importer of lithium resources,showing a severely unbalanced relationship between supply and demand for lithium resources.Therefore,there is an urgent need for the prospecting,exploitation,and study of lithium resources in China.This study collected,organized,and summarized the data on the major lithium deposits in China,analyzed and compared the spatial-temporal distribution patterns,geological characteristics,and metallogenic regularity of these lithium deposits,and summarized the prospecting and research achievements over the last decade.The major lithium deposits in China are distributed in provinces and regions such as Qinghai,Jiangxi,Sichuan,Tibet,and Xinjiang.These deposits are mostly small in scale.According to different genetic types,this study divided lithium deposits into granitic pegmatite type,granite type,saline lake brine type,underground brine type,and sedimentary type,as well as new types including hot spring type and magmatic-hydrothermal type,and summarized the characteristics and key metallogenic factors of these different types of deposits.Sixteen metallogenic prospect areas of lithium deposits were delineated according to the deposit types and the distribution patterns of metallogenic belts.The paper introduced the research progress in major metallogenic models and lithium extraction techniques made over the past decade.Based on the comprehensive analysis of the prospecting potential of lithium deposits,the authors concluded that the future prospecting of lithium resources in China should focus on lithium metallogenic belts,the deep and peripheral areas of currently determined large-scale pegmatite-type lithium deposits,geophysical-geochemical anomalous areas with mineralization clues,and areas with developed large-scale low-grade associated granite-type and sedimentary lithium resources.The study aims to serve as a guide for the future prospecting of lithium deposits in China.展开更多
As China＇s most important gold-producing district, the Jiaodong Peninsula also contains copper, lead-zinc, molybdenum （tungsten）, and other nonferrous metal ore deposits, but the space-time and genetic relationship...As China＇s most important gold-producing district, the Jiaodong Peninsula also contains copper, lead-zinc, molybdenum （tungsten）, and other nonferrous metal ore deposits, but the space-time and genetic relationships with gold deposits remain uncertain. To investigate the temporal relationship between these nonferrous metal and gold ore deposits, We collected the samples from a number of nonferrous metallic and silver deposits and metallogenetic rock bodies in the eastern Jiaodong Peninsula for isotopic dating. The results show that the Re-Os isotopic model ages of the Lengjia molybdenum deposit in Rongcheng range from 114.5 ± 1.8 Ma to 112.6 ± 1.5 Ma, with an average age of 113.6 ± 1.6 Ma; the LA-ICP-MS ^206pb/^238U ages of 33 zircons in the sericitization porphyritic monzogranite that hosts the Tongjiazhuang silver deposit in Rongcheng range between 122 Ma and 109 Ma, with a weighted mean age of 116.04 ± 0.95 Ma; the LA-ICP-MS ^206pb/^238U ages of 31 zircons in the copper metallogenic pyroxene monzodiorite that hosts the Kuangbei copper deposit in Rongcheng range from 126 Ma to 106 Ma, with a weighted mean age of 116.6 ± 1.7 Ma; and the LA-ICP-MS ^206pb/^238U ages of 19 zircons in the pyroxene monzodiorite surrounding the Dadengge gold and multimetal deposit in Weihai range from 113 Ma to 110 Ma, with a weighted mean age of 111.7 ± 0.6 Ma. All these results indicate that the metallogenic ages of the silver and nonferrous metallic deposits in the Jiaodong Peninsula are in a limited range from 118 Ma to 111 Ma. Previous studies have demonstrated that the isotopic ages of gold deposits in the Jiaodong Peninsula range from 123 Ma to 110 Ma, while Weideshanian magmatism occurred between 126 Ma to 108 Ma. Both these ranges are grossly consistent with the metallogenic ages of silver and nonferrous metallic deposits in this study, suggesting that the large-scale mineralization occurred in the Early Cretaceous when magmatic activities were strong. This epoch may be linked to the lithosphere thinning and the thermo-upwelling extension in eastern China at that time. In addition, field investigation also shows that gold and nonferrous metallic deposits are distributed nearby the Weideshanian granite, with the nonferrous metallic deposits lying within or surrounding the granite pluton and the gold deposits outside the granite pluton. We propose the following mineralization scenario： In the Early Cretaceous, an intensive lithospheric extension induced partial melting and degassing of the metasomatized lithospheric mantle, which resulted in the formation of mantle-derived fluids enriched in metal elements. During the rapid process of magma ascent and intrusion, crust-derived fluids were activated by the magmatic thermal dome and served to further extract ore-forming materials from the crust. These fluids may have mixed with the mantle-derived fluid to form a crust-mantle mixing-type ore-forming fluid. The high-temperature conditions in the center or in contact with the granitic magmatic thermal dome would have been favorable for the formation of porphyry-type, skarn-type, and hydrothermal-vein-type ores, thus forming a series of Mo（W）, Cu, and Pb-Zn deposits in the mid-eastern Jiaodong Peninsula. In contrast, the medium- to low-temperature conditions in the periphery of the magmatic thermal dome would have favored the deposition of gold （silver） ores under the appropriate physiochemical and structural conditions. The metaliogenic epoch of the molybdenum, copper, and silver deposits, and their spatio-temporal and genetic relations to the gold deposits, as demonstrated in this study, not only provide important insights to the study of regional metallogeny, our understanding of the metallogenesis of the Jiaodong type gold deposit, and the geodynamic background of the large-scale mineralization in the Jiaodong Peninsula, but also have practical value in guiding the mineral exploration.展开更多
The carbonaceous-siliceous-argillitic rock type uranium deposit in the Zoige area is located in the northeastern margin of the Tibetan Plateau, and has gained much attention of many geologists and ore deposit experts ...The carbonaceous-siliceous-argillitic rock type uranium deposit in the Zoige area is located in the northeastern margin of the Tibetan Plateau, and has gained much attention of many geologists and ore deposit experts due to its scale, high grade and abundant associated ores. Because of the insufficient reliable dating of intrusive rocks, the relationship between mineralization and the magmatic activities is still unknown. In order to study this key scientific issue and the ore-forming processes of the Zoige uranium ore field, the LA-ICP-MS zircon U-Pb dating of magmatic rocks was obtained：64.08±0.59 Ma for the granite-prophyry and ~200 Ma for the dolerite. U-Pb dating results of uraninite from the Zoige uranium ore field are mainly concentrated on ~90 Ma and ~60 Ma. According to LA-ICP-MS U-Pb zircon dating, the ages for the dolerite, porphyry granite and granodiorite are 200 Ma, 64.08 Ma approximately and 226.5-200.88 Ma, respectively. This indicates that the mineralization has close relationship with activities of the intermediate-acidic magma. The ages of the granite porphyry are consistent with those uraninite U-Pb dating results achieved by previous studies, which reflects the magmatic and ore-forming event during the later Yanshanian. Based on the data from previous researches, the ore bodies in the Zoige uranium ore field can be divided into two categories：the single uranium type and the uranium with polymetal mineralization type. The former formed at late Cretaceous（about 90 Ma）, while the latter, closely related to the granite porphyry, formed at early Paleogene（about 60 Ma）. And apart from ore forming elemental uranium, the latter is often associated with polymetallic elements, such as molybdenum, nickel, zinc, etc.展开更多
Red clay type gold deposits,located in the south of China,are situated not only in orogenic belts,but also in inner cratons,where climate is tropical-subtropical with clear arid and humid.The lateritic weathering crus...Red clay type gold deposits,located in the south of China,are situated not only in orogenic belts,but also in inner cratons,where climate is tropical-subtropical with clear arid and humid.The lateritic weathering crust often can be divided into five zones,including topsoil,siliceous duricrust zone,multi-color zone(or red clay zone in some deposits),pallid zone and saprolite zone from surface to the base rock,several of which are absent in some deposits.The base rocks are composed mainly of carbonate rocks with minor clastic rocks,intermediate-basic volcanic rocks and intermediate-acid and alkalic intrusions.The orebodies are mainly located in the multi-color zone with part of them in the pallid and saprolite zones.The ore sources include orebodies of Carlin-type gold deposits and porphyry gold deposits,as well as gold-rich base rocks.The red clay type gold deposits experienced early-stage endogenic gold mineralization and laterization during the Tertiary and Quaternary.The areas with endogenic gold deposits,especially Carlin-type gold deposits and porphyry gold deposits in karst depressions on the plateau,structual erosional platforms in the middle-lower mountains,and intermountain basins in southern China are well worth studying to trace red clay type gold deposits.展开更多
Tungsten ore resources are abundant in China with relatively complete types of deposits. Skarn type and quartz vein type deposits are dominated in the tungsten resources, whereas quartz vein type wolframite deposits a...Tungsten ore resources are abundant in China with relatively complete types of deposits. Skarn type and quartz vein type deposits are dominated in the tungsten resources, whereas quartz vein type wolframite deposits are most important in terms of exploitation and utilization. Skarn type tungsten deposits are concentratedly distributed in the central Nanling region, such as South Hunan, South Anhui and the eastern Qinling region, while quartz vein type tungsten deposits occur mainly in South China, such as West Fujian, South Jiangxi, North Guangdong and South Hunan. The most important metallogenic epoch of tungsten is the Mesozoic, while the metallogenic tectonic setting is featured by an intracontinental environment after orogeny with sever tectonic movements, deep-seated faults and frequent magmatic activities, especially Mesozoic granitoids closely related to tungsten-tin mineralization. 22 metallogenic series of ore deposits characterized by or significantly related to tungsten were defined based on precise statistic information of 1199 tungsten mining areas and thorough the summary of metallogenic regularities. Based on studies of the metallogenic regularity of tungsten deposits, skarn type （or greisen type）, quartz vein type and massif-type of tungsten deposits are thought to be the key prediction types. 65 tungsten-forming belts and 22 key ore concentration areas were ascertained and a distribution map of tungsten-forming belts of China was compiled, which provided a theoretical basis for evaluation and prediction of potential tungsten resources.展开更多
The Bulong gold deposit, located in the southwest Tianshan in China, occurs in the Upper Devonian finegrained clastic rocks. The gold orebodies are controlled by an gently inclined interlayer fractured zone. They are ...The Bulong gold deposit, located in the southwest Tianshan in China, occurs in the Upper Devonian finegrained clastic rocks. The gold orebodies are controlled by an gently inclined interlayer fractured zone. They are hosted only in quartz-barite veins though there are barite veins and quartz veins in the ore district. The δ34S values of pyrite in the ores range from 14.6‰ to 19.2‰ and those of barite from 35.0‰ to 39.6‰, indicating that the sulfur was derived from the strata. 3He/4He ratios of fluid inclusions in pyrite are 0.24-0.82 R/Ra, approximating to that of the crust. The 40Ar/39Ar ratios range from 338 to 471, slightly higher than that of the atmosphere. 40Ar /4He ratios of ore fluids range from 0.015 to 0.412 with a mean of 0.153. Helium and argon isotope compositions of fluid inclusions show that the ore fluids of the Bulong gold deposit were mainly derived from the crust.展开更多
The Duocaima carbonate-hosted Pb-Zn deposit is a newly found large deposit in the southern area of Qinghai Province.In this paper, the characteristics, genesis, significance to Pb-Zn mineralization of the widely devel...The Duocaima carbonate-hosted Pb-Zn deposit is a newly found large deposit in the southern area of Qinghai Province.In this paper, the characteristics, genesis, significance to Pb-Zn mineralization of the widely developed breccias, and the ore-forming process have been carefully studied based on geological documentation of drilling holes, microscopic observations of petrography and microstructure and some stable isotope measurements.Based on the compositions of the clast and matrix, the breccias can be classified into three types： limestone clasts cemented by marl; limestone clasts with fine-grained calcareous materials; and limestone clasts cemented by hydrothermal calcite.The mineralization in the first type of breccia is weak, whereas it is strong in the latter two types of breccias.According to the locations of occurrence and structural characteristics of the breccias along with the relationship between the breccias and mineralization, part of the limestone clasts that are cemented by marl and outcrop in the contact zone between the Wudaoliang Formation（Nw） and the underlying Jiushidaoban Formation（Pj） are attributed to synsedimentary fault-genetic breccia, whereas the last of the limestone clasts that are cemented by marl and developed in the Jiushidaoban Formation（Pj） are attributed to the breccia generated by karst cave collapse; the limestone clasts with fine-grained calcareous materials and the limestone clasts cemented by hydrothermal calcite are attributed to breccia formed by hydrothermal dissolution.The breccia formed by karst collapse had consistently evolved for a long period of time, while the breccias with other origins were formed around the period of mineralization（i.e., about or slightly later than 20–16 Ma）.The breccia generated by karst cave collapse and hydrothermal dissolution are somewhat related; the formation of the breccia from karst cave collapse provided open space for the later mineralization and reaction between hydrothermal fluids and host rocks, and the subsequent strong dissolution by hydrothermal fluids transformed some of the breccia formed earlier by karst cave collapse.Meanwhile, carbonate host rocks with breccias and brecciaed mineralization can be a potential sign of Mississippi Valley Type（MVT） deposits and important indicators for regional mineral exploration.The δ13CV-PDB, δ18OVSMOW, and 87Sr/86 Sr values of hydrothermal calcite in the Duocaima deposit range from 4.3‰ to 7.1‰, 14.9‰ to 20.1‰, and 0.707494 to 0.708185, respectively; the δ13CV-PDB, δ18OV-SMOW, and 87Sr/86 Sr values of the host limestones of the Jiushidaoban Formation range from 3.6‰ to 5.3‰, 18.0‰ to 20.5‰, and 0.707372 to 0.707945, respectively.The δ13CV-PDB and 87Sr/86 Sr values of hydrothermal calcite and limestone are similar, indicating single sources of C and Sr in this deposit, with the likely source being the limestone of the Jiushidaoban Formation.The minor scattering of the δ18OV-SMOW values suggests that different O isotope fluids underwent the isotope exchange reaction.The C-O-Sr isotope characteristics indicate that the host limestones experienced a dissolution and precipitation process during mineralization, which is beneficial to improving the porosity of host rocks and promoting the precipitation of metal sulfides.The δ34SV-CDT value of the breccia-type mineralization sulfides ranges from-30.4‰ to-0.3‰; that is, the δ34SV-CDT value is negative with considerable variation, illustrating that during the breccia-type mineralization process, the bacteriogenic reduction of sulfates provided the vast majority of sulfur, whereas the thermochemical reduction of sulfates was relatively unimportant.The brecciation that occurred as a result of karst cave collapse was mainly generated by the dissolution of groundwater; however, the brecciation related to hydrothermal dissolution and mineralization processes were caused by mixing of different fluids.展开更多
The Mengqiguer deposit in the southern Yili basin Ili Basin is a large interlayer-oxidation-zone type uranium deposit.In this paper,we applied multiple methods including microscopic observation,scanning electron micro...The Mengqiguer deposit in the southern Yili basin Ili Basin is a large interlayer-oxidation-zone type uranium deposit.In this paper,we applied multiple methods including microscopic observation,scanning electron microscope and electronic probe,to analyze the systematical alteration characteristics of the ore-bearing sandstone layer.Fluid inclusion and stable isotope studies on the ore-bearing sandstone have also been carried out to discuss the internal relations between fluid activities,epigenetic alteration and the uranium mineralization.Major epigenetic alteration include clay alteration,carbonatization and pyritization,of which biogenetic pyritization is most closely related to the uranium mineralization.This suggests the existence of microorganism during the uranium mineralization process.The mineralization fluids of low temperature,medium density but varied salinities are suggested to be derived from multi-source,including the meteoric water and organic acidic vapor components from coal-bearing strata.Uranium mineralization,grain-dispersed kaolinite,limonite,colloidal pyrite,and the carbonate cements associated with sulfate-reducing bacteria were formed by meteoric water and vermicular-shaped kaolinite,autologous pyrite,and the carbonate cementation associated with the dehydroxylation of organic matter was formed by organic acidic.Based on these results,we consider that the uranium mineralization and epigenetic alteration both resulted from the reciprocity of organic–inorganic fluid and fluid–rock during the formation of the interlayer oxidation zone.展开更多
Although some porphyry-skarn deposits occur in post-collisional extensional settings,the post-collisional deposits remain poorly understood.Here the authors describe the igneous geology,and mineralization history of T...Although some porphyry-skarn deposits occur in post-collisional extensional settings,the post-collisional deposits remain poorly understood.Here the authors describe the igneous geology,and mineralization history of Tuolangla,a newly-discovered porphyry-skarn Cu-W-Mo deposit in southern Tibet that belongs to the post-collisional class.The deposit is associated with Lower Cretaceous Bima Formation.It was intruded by granodiorite porphyry intrusions at about 23.1 Ma.Field investigation indicated that mineralization is spatially and temporally associated with granodiorite porphyry.Molybdenite yielded a Re-Os weighted mean age of 23.5±0.3 Ma and is considered to represent the age of skarn mineralization at the deposit.Theδ^34S values of sulfides,concentrated in a range between 0.6‰to 3.4‰,show that the sulfur has a homogeneous source with characteristics of magmatic sulfur.The Pb isotopic compositions of sulfides indicate that ore-forming metal materials were derived from the mantle and ancient crust.The granodiorite porphyry displays high SiO2(68.78%–69.75%)and K2O(3.40%–3.56%)contents,and relatively lower Cr(2.4×10^-6–4.09×10^-6),Ni(2.79×10^-6–3.58×10^-6)contents,and positiveεHf(t)values(7.7–12.9)indicating that the mineralization porphyry was derived from the partial melting of juvenile lower crust.The Tuolangla deposit is located in the central part of Zedang terrane.This terrane was once considered an ancient terrane.This terrane is in tectonic contact with Cretaceous ophiolitic rocks to its south and Mesozoic continental margin arc volcanics and intrusions of the Gangdese batholith of the Lhasa terrane to its north.Thus,the authors proposed that the Oligocene porphyry skarn Cu-W-Mo mineralization is probably associated with the Zedang terrane.This finding may clarify why the Oligocene(about 23 Ma)deposits are found only in the Zedang area and why mineralization types of the Oligocene mineralization are considerably different from those of the Miocene(17–14 Ma)mineralization.展开更多
基金funded by the major research program of the of National Natural Science Foundation of China entitled Metallogenic Mechanisms and Regularity of the Lithium Ore Concentration Area in the Zabuye Salt Lake, Tibet (91962219)Science and Technology Major Project of the Tibet Autonomous Region ’s Science and Techonlogy Plan (XZ202201ZD0004G01)a geological survey project of China Geological Survey (DD20230037)。
文摘A reasonable classification of deposits holds great significance for identifying prospecting targets and deploying exploration. The world ’s keen demand for lithium resources has expedited the discovery of numerous novel lithium resources. Given the presence of varied classification criteria for lithium resources presently, this study further ascertained and classified the lithium resources according to their occurrence modes, obtaining 10 types and 5 subtypes of lithium deposits(resources) based on endogenetic and exogenetic factors. As indicated by surveys of Cenozoic exogenetic lithium deposits in China and abroad,the formation and distribution of the deposits are primarily determined by plate collision zones, their primary material sources are linked to the anatectic magmas in the deep oceanic crust, and they were formed primarily during the Miocene and Late Paleogene. The researchers ascertained that these deposits,especially those of the salt lake, geothermal, and volcanic deposit types, are formed by unique slightly acidic magmas, tend to migrate and accumulate toward low-lying areas, and display supernormal enrichment. However, the material sources of lithium deposits(resources) of the Neopaleozoic clay subtype and the deep brine type are yet to be further identified. Given the various types and complex origins of lithium deposits(resources), which were formed due to the interactions of multiple spheres, it is recommended that the mineralization of exogenetic lithium deposits(resources) be investigated by integrating tectono-geochemistry, paleoatmospheric circulation, and salinology. So far, industrialized lithium extraction is primarily achieved in lithium deposits of the salt lake, clay, and hard rock types. The lithium extraction employs different processes, with lithium extraction from salt lake-type lithium deposits proving the most energy-saving and cost-effective.
基金supported by NNSF (No.41572060)projects of CGS (NO.12120113095900)+2 种基金university and company cooperation (2012-01)YM Lab(2011)Innovation Team of Yunnan province and KMUST (2008,2012)
文摘1 Introduction The Laurani porphyry deposit is located in the Altiplano,an extensive North-South trending structural basin that formed in Central-Andean metallogenic belt,Bolivia.The Altiplano poly-metallic province contains sub-volcanic ore
文摘On the basis of the studies of field geology, strontium, hydrogen and oxygen isotopes and REEgeochemistry, coupled with the dating of mineralization, the authors suggest a minerogenetic model of circula-tion and drawing of Late Cretaceous geothermal waters for the fluorite deposits in southeastern China. Thismodel includes two types of mechanism: 1) the leaching-out and drawing through deep circulation of thegeothermal water, and 2) the leaching-out and drawing through shallow circulation of the water. The fluoritemineralization of Mesozoic volcanic rock terrain is related mainly to the former mechanism, with the mineraliz-ing material coming chiefly from the Precambrian metamorphic rocks of the basement underlying the hostrocks; while that of Yanshanian granite terrain is associated with the latter mechanism, with the mineralizingmaterial derived primarily from the host granites and sedimentary rocks.
基金financially supported by the Special fund for Foreign Mineral Resources Risk Exploration (Grant No.Sichuan Financial Investment (2010)331)China Geological Survey (Grant No.12120114012501)
文摘The Phlaythong large iron deposit in Shampasak of southern Laos,is located in the Kon Tum microblock （Fig.1A）,central-southern part of the Indo-China block,and the geographic coordinate of the central mining area is 14°43′04″ N and 106°07′02″ E.
基金funded by the Chinese Geological Survey(Grant no.12120114039601,1212011121037,1212011220369)
文摘China has widely distributed silver deposits,and is rich in silver resources.Although silver deposits are mainly associated with Pb-Zn deposits,a number of independent silver deposits have also been discovered in recent years.Silver deposits include different types,such as submarine volcanism and continental volcanism related type,intrusion related type,and sedimentary related type.This study summarized the metallogenic regularity of China＇s silver deposits systematically based mainly on the data from 490 silver deposits.It is shown that submarine volcanic sedimentary type,continental volcanic or sub-volcanic type,skarn type,hydrothermal type（including vein type and stratabound type）,sedimentary metamorphic type,sedimentary type and regolith type should be regarded as the most important prediction types of silver deposit.A total of 32 silver mineralization belts and 111 silver concentration areas have been delineated.The map of ＂Spatial distribution of silver mineralization belts in China＂ and other series of maps finished in this study may provide a theoretical basis for the evaluation and prognosis of silver resources potential in China.
基金funded by the National Natural Science Fund for Youth(Grant No.41402069)Scientific Research Fund of the China Central Non-Commercial Institute(Grant No.1305,K1022 and K1001)+1 种基金Geological Survey Program of comprehensive study of Chinese mineral geology and regional metallogenic regularity (Grant No.12120114039701,12120114039601)mineral resources potential evaluation(Grant No. 1212010633901)
文摘Molybdenum is one of the dominant minerals in China because of its rich reserves.In recent years,outstanding breakthroughs have been made in molybdenum prospecting in China,and the distribution of molybdenum deposits in China is found to have a ＂planar pattern＂.In general,the molybdenum deposits are concentrated in eastern China,including the largest molybdenum reserves of Henan Province.In terms of the scale of molybdenum deposits,the identified resources of the superlarge deposits are the most important,which account for about 53% of the whole country,and those of the large deposits account for about 30%,those of the medium-sized deposits account for about 14%,those of the small-sized deposits,mine spots and mineralization account for about 3%.The molybdenum deposits are mainly classified as porphyry type,skarn type,hydrothermal（vein） type and sedimentary（metamorphic） type in genesis,and the identified resources of these types account for 85.75%,8.83%,2.79%and 2.63% of the total resources respectively.Based on the statistics of precise chronology data of molybdenites Re-Os,Mo-mineralization can be divided into 6 periods in Chinese geological history,which are Precambrian（〉800 Ma）,Cambrian-Silurian（540-415 Ma,Caledonian）,Devonian-Permian（400-290 Ma,Hecynian）,Triassic（260-200 Ma,Indosinian）,Jurassic-Cretaceous（195-70 Ma,Yanshanian） and Paleogene-Neogene（65-10 Ma,Himalayan）.Mo mineralization during the Yanshanian period is the strongest one,in which about 76.69% of the Chinese total identified resources was formed.The second is the Himalayan period.According to spatial-temporal distribution characteristics of molybdenum deposits,the metallogenic regularity of molybdenum deposits was preliminarily summarized,and 41 level-Ⅲ molybdenum-forming belts,13 level-Ⅱ molybdenum-forming provinces and 4 level-Ⅰ molybdenum-forming domains were ascertained in the mainland of China.There are 39 metallogenic series of and 60 sub-series of molybdenum deposits with molybdenum as the dominant metal and corresponding representative molybdenum deposits proposed.Metallogenic lineages of molybdenum deposits were also established.Spatial-temporal evolution of different types of molybdenum deposits,and the relationship between Mo-mineralization and tectonic evolution have been discussed in this paper.On this basis,the authors think that element Mo is an effective tracer for recording the crustal evolution history of China.At present,there are some problems in the exploration of Mo deposits in China,such as uneven exploration degrees in eastern and western China,shallow exploration depth,low and uneven grade,complex associated components,difficulty of mineral development and utilization,increasing costs of prospecting,and so on.According to successful experience of superficial and deep prospecting and considering also the discussion above,some suggestions are proposed for the prospecting of molybdenum deposits in the future.
基金funded by Geological Survey Projects of the CGS(Grant No.12120115065601,1212011121037,12120114039601,121201120369)
文摘Among the abundant aluminum ore resources in China, bauxite is dominated, which is mainly distributed in 19 provinces and regions, including Shanxi, Henan, Guizhou and Guangxi. The major deposit type of bauxite is paleo-weathering crust sedimentary type, and the other one is the accumulation type. The main metallogenic period is the late Paleozoic Era followed by the Cenozoic Era. The metallogenic tectonic background is characterized by a cratonic environment. This paper summarizes the bauxite metallogenic regularity based on the characteristics of bauxite resources, bauxite deposit type, bauxite metallogenic belt and metallogenic series in China, and 15 bauxite metallogenic belts, 8 bauxite metallogenic series and 7 bauxite ore concentrated areas were identified in the study. This paper also provides a theoretical basis for the evaluation of the potential of bauxite resources.
文摘This paper deals with the metallogenic model of the sandstone type uranium deposit in the northeastern Ordos Basin from aspects of uranium source, migration and deposition. A superposition metallogenic model has been established due to complex uranium mineralization processes with superposition of oil-gas reduction and thermal reformation.
基金funded by Geological Survey Program of China Geological Survey(DD20190816,DD20160057,DD20190606).
文摘Fluorite is one of the important mineral raw materials in the industry.In China,it is mainly distributed in the provinces and regions such as Hunan,Zhejiang,Jiangxi,Inner Mongolia,Fujian,and Henan provinces,boasting huge reserves and large numbers of deposits.However,most of the fluorite deposits are on a small or medium scale.The main fluorite deposits in China were studied in this paper.Their geological features and metallogenic regularity were summarized and compared.Meanwhile,based on their main genetic factors including metallogenic fluid sources and main metallogenic geological processes,they were divided into two groups,namely meso-epithermal deposits and magmatic-hydrothermal deposits.Furthermore,based on the prospecting achievements and research progress obtained in fluorite deposits in recent years,prospecting potential predictions were made for the metallogenic prospect areas and major prospecting areas of fluorite in China.This aims to provide a theoretical basis and direction for future fluorite prospecting in China.
基金funded by the Major Research Plan of the National Natural Science Foundation of China(Grant No.92062217)the project of China Geological Survey(DD20190405).
文摘China is rich in abundant lithium resources characterized by considerable reserves and a concentrated distribution of metallogenic zones or belts,with proven reserves of 4046.8×10^(3) t(calculated based on Li_(2)O)by 2021.China is also a big consumer of lithium.By 2019,China’s lithium consumption in the battery sector alone had reached 99×10^(3) t,with an average annual growth rate of nearly 26%.China has become the world’s largest importer of lithium resources,showing a severely unbalanced relationship between supply and demand for lithium resources.Therefore,there is an urgent need for the prospecting,exploitation,and study of lithium resources in China.This study collected,organized,and summarized the data on the major lithium deposits in China,analyzed and compared the spatial-temporal distribution patterns,geological characteristics,and metallogenic regularity of these lithium deposits,and summarized the prospecting and research achievements over the last decade.The major lithium deposits in China are distributed in provinces and regions such as Qinghai,Jiangxi,Sichuan,Tibet,and Xinjiang.These deposits are mostly small in scale.According to different genetic types,this study divided lithium deposits into granitic pegmatite type,granite type,saline lake brine type,underground brine type,and sedimentary type,as well as new types including hot spring type and magmatic-hydrothermal type,and summarized the characteristics and key metallogenic factors of these different types of deposits.Sixteen metallogenic prospect areas of lithium deposits were delineated according to the deposit types and the distribution patterns of metallogenic belts.The paper introduced the research progress in major metallogenic models and lithium extraction techniques made over the past decade.Based on the comprehensive analysis of the prospecting potential of lithium deposits,the authors concluded that the future prospecting of lithium resources in China should focus on lithium metallogenic belts,the deep and peripheral areas of currently determined large-scale pegmatite-type lithium deposits,geophysical-geochemical anomalous areas with mineralization clues,and areas with developed large-scale low-grade associated granite-type and sedimentary lithium resources.The study aims to serve as a guide for the future prospecting of lithium deposits in China.
基金funded by Taishan Scholar Special Project Funds(ts201511076)Key Research and Development Project of Shandong Province(2017CXGC1604)
文摘As China＇s most important gold-producing district, the Jiaodong Peninsula also contains copper, lead-zinc, molybdenum （tungsten）, and other nonferrous metal ore deposits, but the space-time and genetic relationships with gold deposits remain uncertain. To investigate the temporal relationship between these nonferrous metal and gold ore deposits, We collected the samples from a number of nonferrous metallic and silver deposits and metallogenetic rock bodies in the eastern Jiaodong Peninsula for isotopic dating. The results show that the Re-Os isotopic model ages of the Lengjia molybdenum deposit in Rongcheng range from 114.5 ± 1.8 Ma to 112.6 ± 1.5 Ma, with an average age of 113.6 ± 1.6 Ma; the LA-ICP-MS ^206pb/^238U ages of 33 zircons in the sericitization porphyritic monzogranite that hosts the Tongjiazhuang silver deposit in Rongcheng range between 122 Ma and 109 Ma, with a weighted mean age of 116.04 ± 0.95 Ma; the LA-ICP-MS ^206pb/^238U ages of 31 zircons in the copper metallogenic pyroxene monzodiorite that hosts the Kuangbei copper deposit in Rongcheng range from 126 Ma to 106 Ma, with a weighted mean age of 116.6 ± 1.7 Ma; and the LA-ICP-MS ^206pb/^238U ages of 19 zircons in the pyroxene monzodiorite surrounding the Dadengge gold and multimetal deposit in Weihai range from 113 Ma to 110 Ma, with a weighted mean age of 111.7 ± 0.6 Ma. All these results indicate that the metallogenic ages of the silver and nonferrous metallic deposits in the Jiaodong Peninsula are in a limited range from 118 Ma to 111 Ma. Previous studies have demonstrated that the isotopic ages of gold deposits in the Jiaodong Peninsula range from 123 Ma to 110 Ma, while Weideshanian magmatism occurred between 126 Ma to 108 Ma. Both these ranges are grossly consistent with the metallogenic ages of silver and nonferrous metallic deposits in this study, suggesting that the large-scale mineralization occurred in the Early Cretaceous when magmatic activities were strong. This epoch may be linked to the lithosphere thinning and the thermo-upwelling extension in eastern China at that time. In addition, field investigation also shows that gold and nonferrous metallic deposits are distributed nearby the Weideshanian granite, with the nonferrous metallic deposits lying within or surrounding the granite pluton and the gold deposits outside the granite pluton. We propose the following mineralization scenario： In the Early Cretaceous, an intensive lithospheric extension induced partial melting and degassing of the metasomatized lithospheric mantle, which resulted in the formation of mantle-derived fluids enriched in metal elements. During the rapid process of magma ascent and intrusion, crust-derived fluids were activated by the magmatic thermal dome and served to further extract ore-forming materials from the crust. These fluids may have mixed with the mantle-derived fluid to form a crust-mantle mixing-type ore-forming fluid. The high-temperature conditions in the center or in contact with the granitic magmatic thermal dome would have been favorable for the formation of porphyry-type, skarn-type, and hydrothermal-vein-type ores, thus forming a series of Mo（W）, Cu, and Pb-Zn deposits in the mid-eastern Jiaodong Peninsula. In contrast, the medium- to low-temperature conditions in the periphery of the magmatic thermal dome would have favored the deposition of gold （silver） ores under the appropriate physiochemical and structural conditions. The metaliogenic epoch of the molybdenum, copper, and silver deposits, and their spatio-temporal and genetic relations to the gold deposits, as demonstrated in this study, not only provide important insights to the study of regional metallogeny, our understanding of the metallogenesis of the Jiaodong type gold deposit, and the geodynamic background of the large-scale mineralization in the Jiaodong Peninsula, but also have practical value in guiding the mineral exploration.
基金supported financially by the National Natural Scientific Foundation of China (Grants No. 40872069 and 41173059)the National Basic Research Program of China (973 Program) (Grants No. 2015CB453000)+1 种基金China Geological Survey (Grants No. 12120113095500)the Foundation of China Nuclear Geology (Grants No. 201148)
文摘The carbonaceous-siliceous-argillitic rock type uranium deposit in the Zoige area is located in the northeastern margin of the Tibetan Plateau, and has gained much attention of many geologists and ore deposit experts due to its scale, high grade and abundant associated ores. Because of the insufficient reliable dating of intrusive rocks, the relationship between mineralization and the magmatic activities is still unknown. In order to study this key scientific issue and the ore-forming processes of the Zoige uranium ore field, the LA-ICP-MS zircon U-Pb dating of magmatic rocks was obtained：64.08±0.59 Ma for the granite-prophyry and ~200 Ma for the dolerite. U-Pb dating results of uraninite from the Zoige uranium ore field are mainly concentrated on ~90 Ma and ~60 Ma. According to LA-ICP-MS U-Pb zircon dating, the ages for the dolerite, porphyry granite and granodiorite are 200 Ma, 64.08 Ma approximately and 226.5-200.88 Ma, respectively. This indicates that the mineralization has close relationship with activities of the intermediate-acidic magma. The ages of the granite porphyry are consistent with those uraninite U-Pb dating results achieved by previous studies, which reflects the magmatic and ore-forming event during the later Yanshanian. Based on the data from previous researches, the ore bodies in the Zoige uranium ore field can be divided into two categories：the single uranium type and the uranium with polymetal mineralization type. The former formed at late Cretaceous（about 90 Ma）, while the latter, closely related to the granite porphyry, formed at early Paleogene（about 60 Ma）. And apart from ore forming elemental uranium, the latter is often associated with polymetallic elements, such as molybdenum, nickel, zinc, etc.
基金supported by the National Basic Research Program of China(973 Program)(No. 2009CB421008)111 Project(No.B07011)Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT)
文摘Red clay type gold deposits,located in the south of China,are situated not only in orogenic belts,but also in inner cratons,where climate is tropical-subtropical with clear arid and humid.The lateritic weathering crust often can be divided into five zones,including topsoil,siliceous duricrust zone,multi-color zone(or red clay zone in some deposits),pallid zone and saprolite zone from surface to the base rock,several of which are absent in some deposits.The base rocks are composed mainly of carbonate rocks with minor clastic rocks,intermediate-basic volcanic rocks and intermediate-acid and alkalic intrusions.The orebodies are mainly located in the multi-color zone with part of them in the pallid and saprolite zones.The ore sources include orebodies of Carlin-type gold deposits and porphyry gold deposits,as well as gold-rich base rocks.The red clay type gold deposits experienced early-stage endogenic gold mineralization and laterization during the Tertiary and Quaternary.The areas with endogenic gold deposits,especially Carlin-type gold deposits and porphyry gold deposits in karst depressions on the plateau,structual erosional platforms in the middle-lower mountains,and intermountain basins in southern China are well worth studying to trace red clay type gold deposits.
基金supported by the National Natural Science Foundation (Grant No.41202025,41302058)Funds on Basic Researches for Central Public Welfare Academic Institutes (Grant No.ZS1103,K1325,YK1401)the Chinese Geological Survey Project--Geology of Mineral Resources in China (No.1212011220369,1212010633903,12120114039601 and 1212011121037)
文摘Tungsten ore resources are abundant in China with relatively complete types of deposits. Skarn type and quartz vein type deposits are dominated in the tungsten resources, whereas quartz vein type wolframite deposits are most important in terms of exploitation and utilization. Skarn type tungsten deposits are concentratedly distributed in the central Nanling region, such as South Hunan, South Anhui and the eastern Qinling region, while quartz vein type tungsten deposits occur mainly in South China, such as West Fujian, South Jiangxi, North Guangdong and South Hunan. The most important metallogenic epoch of tungsten is the Mesozoic, while the metallogenic tectonic setting is featured by an intracontinental environment after orogeny with sever tectonic movements, deep-seated faults and frequent magmatic activities, especially Mesozoic granitoids closely related to tungsten-tin mineralization. 22 metallogenic series of ore deposits characterized by or significantly related to tungsten were defined based on precise statistic information of 1199 tungsten mining areas and thorough the summary of metallogenic regularities. Based on studies of the metallogenic regularity of tungsten deposits, skarn type （or greisen type）, quartz vein type and massif-type of tungsten deposits are thought to be the key prediction types. 65 tungsten-forming belts and 22 key ore concentration areas were ascertained and a distribution map of tungsten-forming belts of China was compiled, which provided a theoretical basis for evaluation and prediction of potential tungsten resources.
基金the Ministry of Science and Technology of China(grants G 2001CB 409807,G 1999043216).
文摘The Bulong gold deposit, located in the southwest Tianshan in China, occurs in the Upper Devonian finegrained clastic rocks. The gold orebodies are controlled by an gently inclined interlayer fractured zone. They are hosted only in quartz-barite veins though there are barite veins and quartz veins in the ore district. The δ34S values of pyrite in the ores range from 14.6‰ to 19.2‰ and those of barite from 35.0‰ to 39.6‰, indicating that the sulfur was derived from the strata. 3He/4He ratios of fluid inclusions in pyrite are 0.24-0.82 R/Ra, approximating to that of the crust. The 40Ar/39Ar ratios range from 338 to 471, slightly higher than that of the atmosphere. 40Ar /4He ratios of ore fluids range from 0.015 to 0.412 with a mean of 0.153. Helium and argon isotope compositions of fluid inclusions show that the ore fluids of the Bulong gold deposit were mainly derived from the crust.
基金funded by National Nature Science Foundation of China (41273050, 41320104004)National Key Technology R&D Program in the 11th Five year Plan of China (No.2006 BAB01A08)the Geological Survey Project of China (12120114010301, 1212011220908)
文摘The Duocaima carbonate-hosted Pb-Zn deposit is a newly found large deposit in the southern area of Qinghai Province.In this paper, the characteristics, genesis, significance to Pb-Zn mineralization of the widely developed breccias, and the ore-forming process have been carefully studied based on geological documentation of drilling holes, microscopic observations of petrography and microstructure and some stable isotope measurements.Based on the compositions of the clast and matrix, the breccias can be classified into three types： limestone clasts cemented by marl; limestone clasts with fine-grained calcareous materials; and limestone clasts cemented by hydrothermal calcite.The mineralization in the first type of breccia is weak, whereas it is strong in the latter two types of breccias.According to the locations of occurrence and structural characteristics of the breccias along with the relationship between the breccias and mineralization, part of the limestone clasts that are cemented by marl and outcrop in the contact zone between the Wudaoliang Formation（Nw） and the underlying Jiushidaoban Formation（Pj） are attributed to synsedimentary fault-genetic breccia, whereas the last of the limestone clasts that are cemented by marl and developed in the Jiushidaoban Formation（Pj） are attributed to the breccia generated by karst cave collapse; the limestone clasts with fine-grained calcareous materials and the limestone clasts cemented by hydrothermal calcite are attributed to breccia formed by hydrothermal dissolution.The breccia formed by karst collapse had consistently evolved for a long period of time, while the breccias with other origins were formed around the period of mineralization（i.e., about or slightly later than 20–16 Ma）.The breccia generated by karst cave collapse and hydrothermal dissolution are somewhat related; the formation of the breccia from karst cave collapse provided open space for the later mineralization and reaction between hydrothermal fluids and host rocks, and the subsequent strong dissolution by hydrothermal fluids transformed some of the breccia formed earlier by karst cave collapse.Meanwhile, carbonate host rocks with breccias and brecciaed mineralization can be a potential sign of Mississippi Valley Type（MVT） deposits and important indicators for regional mineral exploration.The δ13CV-PDB, δ18OVSMOW, and 87Sr/86 Sr values of hydrothermal calcite in the Duocaima deposit range from 4.3‰ to 7.1‰, 14.9‰ to 20.1‰, and 0.707494 to 0.708185, respectively; the δ13CV-PDB, δ18OV-SMOW, and 87Sr/86 Sr values of the host limestones of the Jiushidaoban Formation range from 3.6‰ to 5.3‰, 18.0‰ to 20.5‰, and 0.707372 to 0.707945, respectively.The δ13CV-PDB and 87Sr/86 Sr values of hydrothermal calcite and limestone are similar, indicating single sources of C and Sr in this deposit, with the likely source being the limestone of the Jiushidaoban Formation.The minor scattering of the δ18OV-SMOW values suggests that different O isotope fluids underwent the isotope exchange reaction.The C-O-Sr isotope characteristics indicate that the host limestones experienced a dissolution and precipitation process during mineralization, which is beneficial to improving the porosity of host rocks and promoting the precipitation of metal sulfides.The δ34SV-CDT value of the breccia-type mineralization sulfides ranges from-30.4‰ to-0.3‰; that is, the δ34SV-CDT value is negative with considerable variation, illustrating that during the breccia-type mineralization process, the bacteriogenic reduction of sulfates provided the vast majority of sulfur, whereas the thermochemical reduction of sulfates was relatively unimportant.The brecciation that occurred as a result of karst cave collapse was mainly generated by the dissolution of groundwater; however, the brecciation related to hydrothermal dissolution and mineralization processes were caused by mixing of different fluids.
基金financially supported by Ministry of Science and Technology(No.2015CB453004)China National Nuclear Corporation(No.LTD1612-4)。
文摘The Mengqiguer deposit in the southern Yili basin Ili Basin is a large interlayer-oxidation-zone type uranium deposit.In this paper,we applied multiple methods including microscopic observation,scanning electron microscope and electronic probe,to analyze the systematical alteration characteristics of the ore-bearing sandstone layer.Fluid inclusion and stable isotope studies on the ore-bearing sandstone have also been carried out to discuss the internal relations between fluid activities,epigenetic alteration and the uranium mineralization.Major epigenetic alteration include clay alteration,carbonatization and pyritization,of which biogenetic pyritization is most closely related to the uranium mineralization.This suggests the existence of microorganism during the uranium mineralization process.The mineralization fluids of low temperature,medium density but varied salinities are suggested to be derived from multi-source,including the meteoric water and organic acidic vapor components from coal-bearing strata.Uranium mineralization,grain-dispersed kaolinite,limonite,colloidal pyrite,and the carbonate cements associated with sulfate-reducing bacteria were formed by meteoric water and vermicular-shaped kaolinite,autologous pyrite,and the carbonate cementation associated with the dehydroxylation of organic matter was formed by organic acidic.Based on these results,we consider that the uranium mineralization and epigenetic alteration both resulted from the reciprocity of organic–inorganic fluid and fluid–rock during the formation of the interlayer oxidation zone.
文摘Although some porphyry-skarn deposits occur in post-collisional extensional settings,the post-collisional deposits remain poorly understood.Here the authors describe the igneous geology,and mineralization history of Tuolangla,a newly-discovered porphyry-skarn Cu-W-Mo deposit in southern Tibet that belongs to the post-collisional class.The deposit is associated with Lower Cretaceous Bima Formation.It was intruded by granodiorite porphyry intrusions at about 23.1 Ma.Field investigation indicated that mineralization is spatially and temporally associated with granodiorite porphyry.Molybdenite yielded a Re-Os weighted mean age of 23.5±0.3 Ma and is considered to represent the age of skarn mineralization at the deposit.Theδ^34S values of sulfides,concentrated in a range between 0.6‰to 3.4‰,show that the sulfur has a homogeneous source with characteristics of magmatic sulfur.The Pb isotopic compositions of sulfides indicate that ore-forming metal materials were derived from the mantle and ancient crust.The granodiorite porphyry displays high SiO2(68.78%–69.75%)and K2O(3.40%–3.56%)contents,and relatively lower Cr(2.4×10^-6–4.09×10^-6),Ni(2.79×10^-6–3.58×10^-6)contents,and positiveεHf(t)values(7.7–12.9)indicating that the mineralization porphyry was derived from the partial melting of juvenile lower crust.The Tuolangla deposit is located in the central part of Zedang terrane.This terrane was once considered an ancient terrane.This terrane is in tectonic contact with Cretaceous ophiolitic rocks to its south and Mesozoic continental margin arc volcanics and intrusions of the Gangdese batholith of the Lhasa terrane to its north.Thus,the authors proposed that the Oligocene porphyry skarn Cu-W-Mo mineralization is probably associated with the Zedang terrane.This finding may clarify why the Oligocene(about 23 Ma)deposits are found only in the Zedang area and why mineralization types of the Oligocene mineralization are considerably different from those of the Miocene(17–14 Ma)mineralization.
