The Bangbule skarn lead-zinc(Pb-Zn)deposit(>1 Mt Zn+Pb)is located in the western Nyainqentanglha polymetallic metallogenetic belt,central Tibet.Lenticular orebodies are all hosted in skarn and developed in the cont...The Bangbule skarn lead-zinc(Pb-Zn)deposit(>1 Mt Zn+Pb)is located in the western Nyainqentanglha polymetallic metallogenetic belt,central Tibet.Lenticular orebodies are all hosted in skarn and developed in the contact zone between the quartz porphyry and carbonate strata of the mid Paleozoic Middle to Upper Chaguoluoma Formation as well as in carbonate and sandstone beds of the Upper Paleozoic Laga Formation.As a newly discovered skarn deposit,the geological background and metallogenesis of this deposit remain poorly understood.Detailed petrological,geochemical and geochronological data of the ore-related quartz porphyry,helps constrain the mineralization age and contributes to discussion on the ore genesis of the Bangbule deposit.Both endoskarn and exoskarn are identified in the Bangbule deposit.From quartz porphyry to carbonate formation,the exoskarn is zoned from proximal garnet skarn to distal pyroxene skarn.Zircon U-Pb dating results show that the quartz porphyry formed at 73.9±0.8 Ma.Geochemical analysis results show that the quartz porphyry has high contents of SiO_(2)(71.40–74.94 wt%)and K_(2)O+Na_(2)O(3.76–8.46 wt%)with A/CNK values of 0.69 to 1.06.Besides,the quartz porphyry is enriched in large ion lithophile elements(LILEs)and light rare earth elements(LREEs)and have lowεNd(t)(from-8.25 to-8.19)and high initial(^(87)Sr/^(86)Sr)i values(0.713611–0.714478).Major,trace elements and whole-rock F concentration analysis results from the endoskarn samples show higher TFe_(2)O_(3),MgO,CaO,Pb+Zn,W,Sn,Mo and F etc.,and lower alkalis(K_(2)O,Na_(2)O,Sr and Ba)than those of fresh quartz porphyry,indicating that the early ore-forming fluids were an Ca-Fe-F-enriched fluid.Massive ore in the proximal skarn might be related to the high F content in the magma,which lowered the solidus temperature of the quartz porphyry magma and caused a lower temperature of the ore-forming fluids,as well as facilitating the precipitation of sphalerite and galena.Based on the geochemical characteristics presented in this study,we propose that the ore-related quartz porphyry was formed by partial melting of crust materials with some juvenile crustal component input.The partial melting of the middle-upper crust after the initial enrichment of lead and zinc elements are important for the formation of Pb-Zn deposits.The case study of the Bangbule deposit has proven that there is still a crust-derived magmatic source region in the western segment of the central Lhasa terrane.Therefore,there is still great potential for Pb-Zn mineralization and Pb-Zn exploration.展开更多
The formation, development and evolution of the Qinling erogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean-Palaeoproterozoic (3.0-1.6 Ga), (2) pl...The formation, development and evolution of the Qinling erogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean-Palaeoproterozoic (3.0-1.6 Ga), (2) plate evolution (0.8-0.2 Ga), and (3) intracontinental orogeny and tectonic evolution in the Mesozoic.The Devonian (D) and Triassic (T) were the key transition period of the tectonic evolution of the Qinling orogenic belt. That is to say, in the Devonian, the Qinling micro-plate was separated from the northern margin of the Yangtze plate (passive continental margin). This period witnessed transition of the micro-plate from the compressional to ex-tensional state, and consequently three types of sedimentary basins were formed, namely, the rift hydrothermal basin in the micro-plate, restricted ocean basin in the south, and residual ocean basin resulting from collision on the northern margin. In the Triassic the Qinling area was turned into the intracontinental orogen.The Devonian and Triassic展开更多
Three global metallogenic belts were formed in the world during Mesozoic and post Mesozoic times. Two of them are situated along the western and eastern Pacific margins, and the third one——the Tethyan Eurasian metal...Three global metallogenic belts were formed in the world during Mesozoic and post Mesozoic times. Two of them are situated along the western and eastern Pacific margins, and the third one——the Tethyan Eurasian metallogenic belt (TEMB) is related to the domain of Eurasian plate and flanked on the south by the Afro Arabian and Indian plates.The general tectonic evolution of the realm where the TEMB was formed is closely connected with the history of Tethys. The emplacement of ore deposits and the development of regional metallogenic units are related to a definitive time interval and to specific tectonic settings such as: (1) Intracontinental rifting along the northern margin of Gondwana and/or fragments already separated; (2) Oceanic environments (i.e. ophiolite complexes and ocean floor sediments) host podiform chromite deposits, volcano sedimentary cupriferous pyrite deposits (Cyprus type), stratiform manganese deposits, and sporadically PGE deposits; (3) Subduction related settings involve mainly porphyry copper deposits, hydrothermal massive sulphide polymetallic deposits, and epithermal deposits. So far identified mineralization of porphyry copper exceeds in the TEMB over 100 million tons of copper metal; and (4) Collision and post collision continent continent setting includes deposits of lead zinc, antimony, gold, in some sectors tin deposits, as well. The giant deposits of Li pegmatite occur sporadically. The TEMB is almost a continuously mineralized belt, but within it, some sectors display specific features of tectonic settings, association of elements, minerals and morphogenetic types of mineralization.展开更多
Bulk-rock elements,isotopes,and zircon U–Pb ages are reported for magmatic rocks in the Dongzi–Changhanboluo Pb–Zn ore district in Chifeng,Inner Mongolia,China.Zircon U–Pb dating identified four stages of magmatis...Bulk-rock elements,isotopes,and zircon U–Pb ages are reported for magmatic rocks in the Dongzi–Changhanboluo Pb–Zn ore district in Chifeng,Inner Mongolia,China.Zircon U–Pb dating identified four stages of magmatism:Late Silurian gabbroic diorite(*420 Ma),Middle Permian monzonite(*274 Ma),Late Jurassic quartz porphyry and ignimbrite,breccia tuff(153–158 Ma)and Early Cretaceous andesitic porphyrite(*127 Ma).Integrating field observations,geochronology,and element and isotope geochemistry indicated a complex petrogenetic history of the magmatic rocks.The gabbroic diorite may have been sourced from EM1-type mantle.The source of the monzonite may have been mantle metasomatized by melt from the subducting plate.The Jurassic volcaniclastic rocks formed in a medium-pressure,high-temperature environment,possibly in the background of crustal thickening in a syncollisional stage and an early postcollisional stage.During this process,shaly sedimentary rocks were brought into the deep crust and heated,followed by the rapid isostatic uplift of the crust,which caused partial melting of the sedimentary rocks.Quartz monzonite porphyry and quartz porphyry formed by partial melting of mantle metasomatized by subducted sediments,but the quartz porphyry experienced high-degree differentiation and evolution.The andesitic porphyrite has characteristics similar to those of Permian monzonite,indicating that its source area was also the zone of mantle metasomatized by subducted sediment.The late Silurian and Permian magmatic rocks in this area most likely formed against a continental arc background related to the subduction of the Paleo-Asian Ocean Plate beneath the North China Plate.The Late Jurassic magmatic rocks suggest that the northern margin of the North China Craton may have been in a postcollisional setting during the Late Jurassic,with no obvious crustal thinning.The Cretaceous andesitic porphyrite may have formed against the background of lithospheric extension and thinning.According to the comprehensive analysis of geological characteristics,diagenetic and metallogenic epochs,and Pb isotope data,the formation of ore bodies in the Dongzi–Changhanboluo ore district was closely related to the Jurassic quartz porphyry.展开更多
By the end of 2020,83 silver deposits(or ore occurrences),including four super-large-scale deposits,nine large-scale deposits,33 medium-scale deposits and 37 small-scale deposits or ore occurrences,have been proved.Th...By the end of 2020,83 silver deposits(or ore occurrences),including four super-large-scale deposits,nine large-scale deposits,33 medium-scale deposits and 37 small-scale deposits or ore occurrences,have been proved.The amount of silver metal exceeds 86000 t with average grade of 100 g/t,which makes Daxing’anling region one of the the most important silver ore belt in China.However,the metallogenic characteristics and metallogenesis need to be clarified.The silver deposits in the study area are classified into three main types,which are magmatic hydrothermal vein type,continental volcano-subvolcanic type and skarn type,respectively.The supergiant deposits include the Shuangjianzishan deposit(silver metal amount of 15214 t with average grade of 138 g/t),the Baiyinchagandongshan deposit(silver metal amount of 9446 t with average grade of 187 g/t),the Huaobaote deposit(silver metal amount of 6852 t with average grade of 170 g/t),and the Fuxingtun deposit(silver metal amount of 5240 t with average grade of 196 g/t).The silver deposits are mainly distributed in the central and south of the Daxing’anling area,and mainly formed in the Yanshanian period.The silver polymetallic deposits in the Daxinganling area are significantly controlled by regional faults and the junction zone of volcanic rock basins and their margins.The north-east trending deep faults are the most important ore-controlling structures in this area.The distribution of silver polymetallic deposits along the main faults is obvious,and the intersection area of multiple groups of faults often form important mine catchments.The Permian is the most important ore-bearing formation in this area,but some important silver polymetallic deposits occur in Mesozoic volcanic basins or pre-Mesozoic strata.The magmatic rocks related to mineralization are mainly intermediate acidic or acidic intrusions,intermediate acidic lavas,pyroclastic rocks,and small intrusions of ultra-shallow or shallow facies of the Yanshanian Period.The mineralization element combination is mainly determined by the elemental geochemical background of surrounding rocks or source layers.In addition,the type of deposit,the distance from the mineralization center,and the degree of differentiation of ore-forming rock mass are also important influence factors.The article analyzes the prospecting prospects of each silver deposit type in the study area,discusses the relationship between mineralization center and deep prospecting,and proposes that porphyry silver deposits should be paid attention to.In the prospecting and exploration of silver deposits,comprehensive evaluation and multi-target prospecting need to be strengthened because silver can coexist or be associated with a variety of metals.展开更多
The?Annage gold deposit is located at the east part of the eastern Kunlun orogenic belt. The characteristics of ore-forming fluids and metallogenesis were discussed by using fluid petrography, micro-thermometry and hy...The?Annage gold deposit is located at the east part of the eastern Kunlun orogenic belt. The characteristics of ore-forming fluids and metallogenesis were discussed by using fluid petrography, micro-thermometry and hydrogen-oxygen isotope analysis. Three stages, namely quartz-pyrite stage (A), quartz-polymetallic-sulfide stage (B) and quartz-ankerite stage (C) were included in the hydrothermal process as indicated by the results of this study. Inclusions developed in ore-bearing quartz veins from stages A and B are of three types: aqueous inclusions (type I), CO2-bearing inclusions (type II) and pure CO2?inclusions (type III). All three types of inclusions, mainly type I, are presented in stage A, having homogenization temperatures at 180°C - 360°C, and salinities ranging from 0.53% to 21.44%. In addition to development of type I inclusions, type II and III inclusions increase significantly in stage B, with homogenization temperatures ranging from 160°C to 330°C, and salinities are from 1.32% to 22.01%. Based on micro-thermometry, fluids in Annage deposit are of H2O-NaCl-CO2?type with medium-high temperature (140°C - 395°C) and medium-low salinity (0.53% - 22.01%). Results of hydrogen-oxygen isotope analysis show that ore-forming fluid is mainly CO2-rich magmatic fluid, mixed with shallow groundwater or metamorphic hydrothermal in the late mineralization stages. Calculated metallogenic pressures are in the range of 79 - 130MPa corresponding to a maximum depth of 4.8 km. The Annage deposit is a mesothermal quartz vein type gold deposit.展开更多
The Lamasu copper polymetallic mineralized region lies in the south of Wenquan County, Xinjiang and in the Northwest lakeside of the Sailimu Lake. Seen from the geotectonic position, it belongs to North Tianshan geodo...The Lamasu copper polymetallic mineralized region lies in the south of Wenquan County, Xinjiang and in the Northwest lakeside of the Sailimu Lake. Seen from the geotectonic position, it belongs to North Tianshan geodome system, Tianshan diwa region, Central Asian crustobody. Copper and zinc polymetallic ore bodies had been formed in the skarn of the contact, between the metamophic carbonate rocks of the Kuximqiek Group, Jixian System and early mid Varisean acidic rockbodies. The formation of the ore deposit was the result of the successive activities of the crust and mantle and the tectonic and magmatic activities.展开更多
The Jiama deposit,a significant porphyry-skarn-type copper polymetallic deposit located within the Gangdese metallogenic belt in Tibet,China,exemplifies a typical porphyry metallogenic system.However,the mineral chemi...The Jiama deposit,a significant porphyry-skarn-type copper polymetallic deposit located within the Gangdese metallogenic belt in Tibet,China,exemplifies a typical porphyry metallogenic system.However,the mineral chemistry of its accessory minerals remains under-examined,posing challenges for resource assessment and ore prospecting.Utilizing electron microprobe analysis and LA-ICP-MS analysis,this study investigated the geochemical characteristics of apatite in ore-bearing granite and monzogranite porphyries,as well as granodiorite,quartz diorite,and dark diorite porphyries in the deposit.It also delved into the diagenetic and metallogenic information from these geochemical signatures.Key findings include:(1)The SiO_(2) content,rare earth element(REE)contents,and REE partition coefficients of apatite indicate that the dark diorite porphyry possibly does not share a cogenetic magma source with the other four types of porphyries;(2)the volatile F and Cl contents in apatite,along with their ratio,indicate the Jiama deposit,formed in a collisional setting,demonstrates lower Cl/F ratios in apatite than the same type of deposits formed in a subduction environment;(3)compared to non-ore-bearing rock bodies in other deposits formed in a collisional setting,apatite in the Jiama deposit exhibits lower Ce and Ga contents.This might indicate that rock bodies in the Jiama deposit have higher oxygen fugacity.Nevertheless,the marginal variation in oxygen fugacity between ore-bearing and non-ore-bearing rock bodies within the deposit suggests oxygen fugacity may not serve as the decisive factor in the ore-hosting potential of rock bodies in the Jiama deposit.展开更多
The Wangfeng gold deposit is one of the five most important gold deposits in the Tian-shan. Studies of its metallogenic time, space, geodynamic background, ore feature and ore fluid have proved that the deposit formed...The Wangfeng gold deposit is one of the five most important gold deposits in the Tian-shan. Studies of its metallogenic time, space, geodynamic background, ore feature and ore fluid have proved that the deposit formed in the late Paleozoic continental collision, and consequently is a suitable delegate to probe mineralizing regularities during collisiona! orogenesis. Isotopic studies including O, D, C, S, Pb and Sr reveal ore materials derived from sedimentary association (including carbonate and sulfate), which further refers to the Hercynian carbonate-silicolite-argillite formation north to Wangfeng camp. At the end of Paleozoic, the southward intracontinental subduction of Hercynian synthem along the Hongwuyueqiao fault down to the Central Tianshan terrane induced large-scale fluidization which extracted and out-transported ore materials from Hercynian synthem upto shallow fair positions, and finally resulted in the formation of the Wangfeng deposit. This study excludes the possibility of other展开更多
Modern collisional orogens represent the natural laboratory for the study of metallogeny in continental collision zones. The Pyrenees, Alps, Zagros and Himalaya are all associated with Neo-Tethyan subduction and repre...Modern collisional orogens represent the natural laboratory for the study of metallogeny in continental collision zones. The Pyrenees, Alps, Zagros and Himalaya are all associated with Neo-Tethyan subduction and represent the youngest collisional orogens on Earth. Here, we compare these four orogens in terms of their composition, architecture, tectonic evolution,and metallogenic systems. The four orogens can be divided into simple and composite types. Simple orogens are represented by the Pyrenees and the Alps, and are characterized by narrow linear shapes in plain view and symmetric structures in cross-section,are free of arc magmatism, and are associated with the Mississippi Valley Valley-type Pb-Zn and orogenic gold deposits. The mineral deposits that form in these simple collisional orogens are generally related to processes that occur in the middle and upper crust. In contrast, composite orogens, as exemplified by the Zagros-Iranian and Himalayan-Tibetan Plateaus, are associated with broad orogenic plateaus in plain view and asymmetrical structures in cross-section, record extensive arc magmatism in continental margins, and are associated with a variety of deposit types including carbonatite-related rare earth element(REE),porphyry Cu-Mo, orogenic Au, Mississippi Valley type Pb-Zn, and detachment-fault-related polymetallic deposits. Although the subduction of Neo-Tethys oceanic crust occurred before the creation of simple collisional orogens in the Pyrenees and the Alps,these areas do not show the record of continental arc magmatism. In contrast, the composite collisional orogens are associated with the development of huge continental margin arcs prior to continental subduction, and the subduction was followed by reactivation of the subduction-modified arc lithospheric material, generating the ore-forming systems in these regions.展开更多
As one of the largest Phanerozoic orogens in the world,the Central Asian Orogenic Belt(CAOB)is a natural laboratory for studies of continental dynamics and metallogenesis.This paper summarizes the research progresses ...As one of the largest Phanerozoic orogens in the world,the Central Asian Orogenic Belt(CAOB)is a natural laboratory for studies of continental dynamics and metallogenesis.This paper summarizes the research progresses of the accretionary processes and metallogenesis of the CAOB since the Peopled Republic of China was founded,and puts forward the prospect for future research.During the early period(1950s-1970s),several geological theories were applied to explain the geological evolution of Central Asia.In the early period of China's reform and opening-up,the plate tectonics theory was applied to explain the evolution of the northern Xinjiang and Xingmeng regions,and the opinion of subduction-collision between Siberian Kazakhstan and China-North Korea-Tarim plates was proposed.The idea of the Solonker-Yanbian suture zone was established.In the 1990s,the study of the CAOB entered a period of rapid development.One school of scholars including geologists from the former Soviet Union proposed a multi-block collision model for the assemblage of the CAOB.In contrast,another school of scholars,led by a Turkish geologist,Celal Sengor,proposed that the Altaids was formed through the growth and strike-slip duplicates of a single island arc,and pointed out that the Altaids is a special type of collisional orogen.During this period,Chinese geologists carried out a lot of pioneering researches on ophiolites and high-pressure metamorphic rocks in northern China,and confirmed the main suture zones accordingly.In 1999,the concept of"Central Asian metallogenic domain"was proposed,and it became one of the three major metallogenic domains in the world.Since the 21st century,given the importance for understanding continental accretion and metallogenic mechanism,the CAOB has become the international academic forefront.China has laid out a series of scientific research projects in Central Asia.A large number of important scientific research achievements have been spawned,including the tectonic attribution of micro-continents,timing and tectonic settings of ophiolites,magmatic arcs,identification and anatomy of accretionary wedges,regional metamorphism-deformation,(ultra)high-pressure metamorphism,ridge subduction plume-plate interaction archipelagic paleogeography and spatio-temporal framework of multiple accretionary orogeny,continental growth accretionary metallogenesis,structural superposition and transformation etc.These achievements have made important international influences.There still exist the following aspects that need further study:(1)Early evolution history and subduction initiation of the Paleo-Asian Ocean;(2)The accretionary mechanism of the extroversion Paleo-Asian Ocean;(3)The properties of the mantle of the Paleo-Asian Ocean and their spatiotemporal distribution;(4)The interaction between the Paleo-Asian Ocean and the Tethys Ocean;(5)Phanerozoic continental growth mechanism and its global comparison;(6)Accretionary metallogenic mechanism of the Central Asian metallogenic domain;and(7)Continental transformation mechanism.展开更多
Many of the Yanshannian intermediate-acid intrusive rocks related to Cu-Au mineraliza-tion in the Eastern Yangtze Block are characterized by high AI2O3, Sr contents, while low in Y, Yb contents, thus with high Sr/Y, a...Many of the Yanshannian intermediate-acid intrusive rocks related to Cu-Au mineraliza-tion in the Eastern Yangtze Block are characterized by high AI2O3, Sr contents, while low in Y, Yb contents, thus with high Sr/Y, and La/Yb ratios, and variational isotope signatures in particular, e.g. εNd(t) = -11.92-1.96, (143Nd/144Nd): = 0.5120-0.5125, TDM= 0.70-1.71 Ga, (7Sr/86Sr), = 0.7043 -0.7076. The geochemical characteristics of these rocks suggest that: (1) these rocks are geo-chemically similar to adakite, which might have been stemmed from the partial melting of thick-ened basaltic lower crust due to basalt underplating; and (2) the high pressure (1.2-4.0 GPa) and high temperature (850-1150℃) surroundings of the lower crust favor both the fluid and ada-kite-like magma to generation. Not only can the adakite-like magma carry abundant fluid and Cu-Au ore-froming materials, but also can it bring them to the shallow part with ease and contrib-utes to the Cu-Au mineralization.展开更多
Porphyry copper±molybdenum±gold deposits(PCDs) are the most representative magmatic-hydrothermal metallogenic system above subduction zones with important economic value. Previous studies revealed that large...Porphyry copper±molybdenum±gold deposits(PCDs) are the most representative magmatic-hydrothermal metallogenic system above subduction zones with important economic value. Previous studies revealed that large PCDs are generally formed from initial arc magmas(from subduction-induced partial melting of the mantle wedge), which eventually ascend to the shallow crust(3–5 km) for mineralization after a series of complex evolution processes. These processes include(1) the dehydration or partial melting of subducting slab, which induces partial melting of the metasomatized mantle wedge;(2)the ascent of mantle-derived magma to the bottom of the lower crust, which subsequently undergoes crustal processes such as assimilation plus fractional crystallization(AFC) or melting, assimilation, storage and homogenization(MASH);(3) the magma chamber formation at the bottom of the lower, middle and upper crust;(4) the final emplacement and volatilization of porphyry stocks;and(5) the accumulation of ore-forming fluids and metal precipitation. Despite the many decades of research, many issues involving the PCD metallogenic mechanism still remain to resolve, such as(1) the tectonic control on the geochemical characteristics of ore-forming magma;(2) the reason for the different lifespans of the long-term magmatic arc evolution and geologically "instantaneous" mineralization processes;(3) the source of ore-forming materials;(4) the relative contributions of metal pre-enrichment to mineralization by the magma source and by magmatic evolution;and(5) the decoupling behaviors of Cu and Au during the pre-enrichment. These issues point out the direction for future PCD metallogenic research, and the resolution to them will deepen our understanding of the metallogenesis at convergent plate boundaries.展开更多
The predominant types of high-grade iron deposits in China include skarn,sedimentary metamorphic(banded ironformation,BIF-type),continental/submarine volcanic-hosted and magmatic Fe-Ti-Voxide deposits.Based on a compr...The predominant types of high-grade iron deposits in China include skarn,sedimentary metamorphic(banded ironformation,BIF-type),continental/submarine volcanic-hosted and magmatic Fe-Ti-Voxide deposits.Based on a comprehensive review of current studies on these deposits,this paper suggests that the oxygen concentration in atmosphere played an important role for the formation of BIFs,whereas the tectonic setting and deep magmatic differentiation processes are more important for the other types.Notably,both high temperature and high pressure experiments and melt inclusion studies indicate that during the differentiation,high temperature magmas could develop iron-rich magma via liquid immiscibility but not pure oxide melt("iron ore magma").Fe-P melt could be generated directly by liquid immiscibility under hydrous and oxidized condition.The formation of high-grade iron deposits is mostly associated with the processes related to multiple stages of superimposition,e.g.,desiliconization and iron enrichment,removal of impurity,and remobilization and re-precipitation of iron.According to the temporal evolution,the high-grade iron deposit could be divided into multi-episode superimposition type(temporally discontinuous mineralization)and multi-stage superimposition type(temporally continuous mineralization).The former is represented by the sedimentary metamorphic iron deposit,and the latter includes those related to magmatic-hydrothermal fluids(e.g.,skarn,volcanic-hosted and magmatic types).展开更多
Mesozoic volcanic rocks are widely distributed in southeastern China. There exist various kinds of subvolcanic granitoids associated with the volcanic rocks. This paper deals with the geological setting, the character...Mesozoic volcanic rocks are widely distributed in southeastern China. There exist various kinds of subvolcanic granitoids associated with the volcanic rocks. This paper deals with the geological setting, the characteristics and the metallogenesis of these subvolcanic granitoids.展开更多
EPITHERMAL gold (copper) deposits distributed in the middle-south parts of Tancheng-Lujiang deep faultzone and its vicinity have close relation to Mesozoic shoshonitic magmatism. According to their metallogenic featur...EPITHERMAL gold (copper) deposits distributed in the middle-south parts of Tancheng-Lujiang deep faultzone and its vicinity have close relation to Mesozoic shoshonitic magmatism. According to their metallogenic features and ore-forming conditions, these deposits can be divided into three types; tellurium-goldtype Au deposit, quartz-adularia type Au deposit and quartz-manganoansiderite type Au-Cu deposit. Therepresentative deposits of them are Guilaizhuang, Dongxi and Tiantoushan. In this note, the general features of the three typical epithermal gold (copper) deposits are outlined and the relationship between mineralization and types of volcanic basins is discussed preliminarily.展开更多
1 Geology Daolundaba copper polymetallic deposit occurs in West Ujimqin Banner,the Xilin Gol League of Inner Mongolia,along the west side of South part of Daxinganling ore belt,whose tectonic position just lies at the...1 Geology Daolundaba copper polymetallic deposit occurs in West Ujimqin Banner,the Xilin Gol League of Inner Mongolia,along the west side of South part of Daxinganling ore belt,whose tectonic position just lies at the junction of Siberian Block in the south part,North China Block in the north and Songliao block in the east.The Daolundaba copper polymetallic deposit is hosted by the Lower Proterozoic Baoyintu group of biotite-plagioclase gneiss(Pt1by),upper Permian Linxi formation of sandy slate(P2l),and the Hercynian Qianjinchang pluton of biotite granite.展开更多
The Dongnan Cu–Mo deposit,located in the southeast of the Zijinshan ore field(the largest porphyry–epithermal system in Southeast China),represents the complex magmatic and metallogenesis events in the region.The pe...The Dongnan Cu–Mo deposit,located in the southeast of the Zijinshan ore field(the largest porphyry–epithermal system in Southeast China),represents the complex magmatic and metallogenesis events in the region.The petrogenesis and metallogenesis of granitoids from the deposit are not determined,especially the interactions between ore-bearing(granodiorite porphyry)and barren samples(granodiorite and diorite).In the paper,the whole rock geochemical features shared a similar affinity to the middle-lower content and revealed that they derived from partial melting of the Cathaysian basement with the contribution of mantle materials,even represented that they generated in the plate subduction;LA-ICP-MS zircon U–Pb ages show that these granodiorites,granodioritic porphyry and diorite,were generated during 114–103 Ma.The ore-bearing samples mostly presented ε_(Hf)(t)of negative values(peak value is-4 to-3)with old two-stage Hf model ages(t_(DM)^(2))(peak value is 1.10–1.15 Ga),while the barren sample showed slightly negative ε_(Hf)(t)(peak value is-1 to 0)values with young t_(DM)^(2)(peak value is 1.00–1.05 Ga).The value of zircon Ce^(4+)/Ce^(3+)ratio mostly higher than 450 was first verified for the ore-bearing samples in the Dongnan Cu–Mo deposit,and the values of ore-bearing were found to be higher than those from the barren,which suggests that the ore-bearing formed in more oxidized parental magma with higher oxygen fugacity.Based on the geochemical characteristic of the element and isotope,we concluded that the Early Cretaceous multiphases magmatic activities,low melting temperature and low pressure of pluton,and high oxygen fugacity of zircon,were the favorable conditions for metallogenesis of Dongnan Cu–Mo deposit.展开更多
The newly-discovered Donglufang Moe Cu porphyry-skarn deposit is located in the southern Yidun Terrane, southeast Tibet, with more than 80 million tonnes(Mt) of reserves(grading 0.15 wt.% Mo and0.48 wt.% Cu) hosted in...The newly-discovered Donglufang Moe Cu porphyry-skarn deposit is located in the southern Yidun Terrane, southeast Tibet, with more than 80 million tonnes(Mt) of reserves(grading 0.15 wt.% Mo and0.48 wt.% Cu) hosted in Triassic strata and Late Cretaceous granodiorite porphyry. Ree Os dating of molybdenum ore yielded a weighted mean age of 84.9 ± 1.0 Ma and an isochron age of 85.2 ± 0.6 Ma.LA-ICP-MS Ue Pb dating of zircons from the granodiorite porphyry yielded206 Pb/238 U ages ranging from 87.4 Ma to 84.2 Ma with a weighted mean206 Pb/238 U age of 85.1 ±0.5 Ma, indicating a temporal linkage between granitic magmatism and Moe Cu mineralization. Geochemical analyses show that the granodiorite porphyries are I-type granites with Si O_2 contents of 64.3 -66.7 wt.%. These rocks are typically metaluminous with high K_2 O/Na_2 O ratios, low Mg O(1.32 -1.56 wt.%), Cr(5.6 -12.9 ppm), Ni(3.79 -10.81 ppm), Mg#(43 -52) values, and high Sr(304 -844 ppm), Sr/Y(21.2 -50.8) and La/Yb ratios(37.0 -60.1). They are enriched in light rare-earth elements(LREE) relative to heavy rare-earth elements(HREE), with slightly negative Eu anomalies, and are enriched in Th, U and large ion lithophile elements(LILE, e.g., K and Rb), and depleted in high field strength elements(HFSE, e.g., Nb, Ta, P and Ti). They also show negative zircon εHf(t) values(-6.7 to -2.3) and negative whole rock εNd(t) values(à5.2 to-4.3), as well as old Hfe Nd model ages, indicating the magmas were derived from a thickened ancient lower crust within the garneteamphibolite facies. Considering the tectonic evolution of the Yidun Terrane, geochemical characteristics of granodiorite porphyry, and the ages of mineralization obtained in this study. We suggest that the Donglufang deposit was formed in a post-collisional setting, which has a genetic relationship with the emplacement of the granodiorite porphyry. The present study provide key information for the exploration of the Late Cretaceous metallogeny in the Yidun Terrane.展开更多
The Altai-Junggar-Tianshan collage in southern Altaids is an important metallogenic domain in Central Asia that contain world-class copper-iron-nickel deposits.As an accretionary-type metallogenic system,the metalloge...The Altai-Junggar-Tianshan collage in southern Altaids is an important metallogenic domain in Central Asia that contain world-class copper-iron-nickel deposits.As an accretionary-type metallogenic system,the metallogenic processes of the Altai-Junggar-Tianshan collage is essential in understanding the genetic mechanism of ore deposits in general.Here in this paper we present a brief introduction to the project on the western part of the Southern Altaids,entitled"The deep structure and metallegenic processes of the North China accretionary metallogenic systems".This project mainly focuses on the deep structure and metallogenic background of the Altai-Junggar-Tianshan collage by integrated studies from field geology,structural mapping,geochemistry and geophysical exploration.Multiple new geological and geophysical methods will be applied to make transparency of the Kalatongke and Kalatage ore clusters.This will update our understanding of the geodynamic processes of metallogenesis and lead to the development and foundation of new metallogenic theories in accretionary orogens.展开更多
基金jointly supported by National Key Research and Development Program of China(Grant No.2022YFC2905002)Special Scientific Research Fund of Tibet Bureau of Geology and Mineral Exploration and Development(Grant No.202119)+2 种基金National Natural Science Foundation of China(Grant No.41902101)Research Start-up Fund of Chengdu University of Technology(Grant No.10912-KYQD2020-08395)the Opening Foundation of MNR Key Laboratory of Metallogeny and Mineral Assessment(Grant No.ZS2101)。
文摘The Bangbule skarn lead-zinc(Pb-Zn)deposit(>1 Mt Zn+Pb)is located in the western Nyainqentanglha polymetallic metallogenetic belt,central Tibet.Lenticular orebodies are all hosted in skarn and developed in the contact zone between the quartz porphyry and carbonate strata of the mid Paleozoic Middle to Upper Chaguoluoma Formation as well as in carbonate and sandstone beds of the Upper Paleozoic Laga Formation.As a newly discovered skarn deposit,the geological background and metallogenesis of this deposit remain poorly understood.Detailed petrological,geochemical and geochronological data of the ore-related quartz porphyry,helps constrain the mineralization age and contributes to discussion on the ore genesis of the Bangbule deposit.Both endoskarn and exoskarn are identified in the Bangbule deposit.From quartz porphyry to carbonate formation,the exoskarn is zoned from proximal garnet skarn to distal pyroxene skarn.Zircon U-Pb dating results show that the quartz porphyry formed at 73.9±0.8 Ma.Geochemical analysis results show that the quartz porphyry has high contents of SiO_(2)(71.40–74.94 wt%)and K_(2)O+Na_(2)O(3.76–8.46 wt%)with A/CNK values of 0.69 to 1.06.Besides,the quartz porphyry is enriched in large ion lithophile elements(LILEs)and light rare earth elements(LREEs)and have lowεNd(t)(from-8.25 to-8.19)and high initial(^(87)Sr/^(86)Sr)i values(0.713611–0.714478).Major,trace elements and whole-rock F concentration analysis results from the endoskarn samples show higher TFe_(2)O_(3),MgO,CaO,Pb+Zn,W,Sn,Mo and F etc.,and lower alkalis(K_(2)O,Na_(2)O,Sr and Ba)than those of fresh quartz porphyry,indicating that the early ore-forming fluids were an Ca-Fe-F-enriched fluid.Massive ore in the proximal skarn might be related to the high F content in the magma,which lowered the solidus temperature of the quartz porphyry magma and caused a lower temperature of the ore-forming fluids,as well as facilitating the precipitation of sphalerite and galena.Based on the geochemical characteristics presented in this study,we propose that the ore-related quartz porphyry was formed by partial melting of crust materials with some juvenile crustal component input.The partial melting of the middle-upper crust after the initial enrichment of lead and zinc elements are important for the formation of Pb-Zn deposits.The case study of the Bangbule deposit has proven that there is still a crust-derived magmatic source region in the western segment of the central Lhasa terrane.Therefore,there is still great potential for Pb-Zn mineralization and Pb-Zn exploration.
基金This project was supported by grants from the Ministry of Science and Technology(969140104)the General Bureau of Geology and Exploration under theformer CNNC(98-D-1).
文摘The formation, development and evolution of the Qinling erogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean-Palaeoproterozoic (3.0-1.6 Ga), (2) plate evolution (0.8-0.2 Ga), and (3) intracontinental orogeny and tectonic evolution in the Mesozoic.The Devonian (D) and Triassic (T) were the key transition period of the tectonic evolution of the Qinling orogenic belt. That is to say, in the Devonian, the Qinling micro-plate was separated from the northern margin of the Yangtze plate (passive continental margin). This period witnessed transition of the micro-plate from the compressional to ex-tensional state, and consequently three types of sedimentary basins were formed, namely, the rift hydrothermal basin in the micro-plate, restricted ocean basin in the south, and residual ocean basin resulting from collision on the northern margin. In the Triassic the Qinling area was turned into the intracontinental orogen.The Devonian and Triassic
文摘Three global metallogenic belts were formed in the world during Mesozoic and post Mesozoic times. Two of them are situated along the western and eastern Pacific margins, and the third one——the Tethyan Eurasian metallogenic belt (TEMB) is related to the domain of Eurasian plate and flanked on the south by the Afro Arabian and Indian plates.The general tectonic evolution of the realm where the TEMB was formed is closely connected with the history of Tethys. The emplacement of ore deposits and the development of regional metallogenic units are related to a definitive time interval and to specific tectonic settings such as: (1) Intracontinental rifting along the northern margin of Gondwana and/or fragments already separated; (2) Oceanic environments (i.e. ophiolite complexes and ocean floor sediments) host podiform chromite deposits, volcano sedimentary cupriferous pyrite deposits (Cyprus type), stratiform manganese deposits, and sporadically PGE deposits; (3) Subduction related settings involve mainly porphyry copper deposits, hydrothermal massive sulphide polymetallic deposits, and epithermal deposits. So far identified mineralization of porphyry copper exceeds in the TEMB over 100 million tons of copper metal; and (4) Collision and post collision continent continent setting includes deposits of lead zinc, antimony, gold, in some sectors tin deposits, as well. The giant deposits of Li pegmatite occur sporadically. The TEMB is almost a continuously mineralized belt, but within it, some sectors display specific features of tectonic settings, association of elements, minerals and morphogenetic types of mineralization.
基金financially supported by the National Natural Science Foundation of China(No.41602101)。
文摘Bulk-rock elements,isotopes,and zircon U–Pb ages are reported for magmatic rocks in the Dongzi–Changhanboluo Pb–Zn ore district in Chifeng,Inner Mongolia,China.Zircon U–Pb dating identified four stages of magmatism:Late Silurian gabbroic diorite(*420 Ma),Middle Permian monzonite(*274 Ma),Late Jurassic quartz porphyry and ignimbrite,breccia tuff(153–158 Ma)and Early Cretaceous andesitic porphyrite(*127 Ma).Integrating field observations,geochronology,and element and isotope geochemistry indicated a complex petrogenetic history of the magmatic rocks.The gabbroic diorite may have been sourced from EM1-type mantle.The source of the monzonite may have been mantle metasomatized by melt from the subducting plate.The Jurassic volcaniclastic rocks formed in a medium-pressure,high-temperature environment,possibly in the background of crustal thickening in a syncollisional stage and an early postcollisional stage.During this process,shaly sedimentary rocks were brought into the deep crust and heated,followed by the rapid isostatic uplift of the crust,which caused partial melting of the sedimentary rocks.Quartz monzonite porphyry and quartz porphyry formed by partial melting of mantle metasomatized by subducted sediments,but the quartz porphyry experienced high-degree differentiation and evolution.The andesitic porphyrite has characteristics similar to those of Permian monzonite,indicating that its source area was also the zone of mantle metasomatized by subducted sediment.The late Silurian and Permian magmatic rocks in this area most likely formed against a continental arc background related to the subduction of the Paleo-Asian Ocean Plate beneath the North China Plate.The Late Jurassic magmatic rocks suggest that the northern margin of the North China Craton may have been in a postcollisional setting during the Late Jurassic,with no obvious crustal thinning.The Cretaceous andesitic porphyrite may have formed against the background of lithospheric extension and thinning.According to the comprehensive analysis of geological characteristics,diagenetic and metallogenic epochs,and Pb isotope data,the formation of ore bodies in the Dongzi–Changhanboluo ore district was closely related to the Jurassic quartz porphyry.
基金financially supported by the projects of China Geological Survey(DD20221695,DD20160346 and DD20190379)the Fundamental Research Funds of the Central Public Welfare Scientific Research Institutes(JYYWF20183701 and JYYWF20183704)the Inner Mongolia Geological Exploration Fund Project(2020-YS03).
文摘By the end of 2020,83 silver deposits(or ore occurrences),including four super-large-scale deposits,nine large-scale deposits,33 medium-scale deposits and 37 small-scale deposits or ore occurrences,have been proved.The amount of silver metal exceeds 86000 t with average grade of 100 g/t,which makes Daxing’anling region one of the the most important silver ore belt in China.However,the metallogenic characteristics and metallogenesis need to be clarified.The silver deposits in the study area are classified into three main types,which are magmatic hydrothermal vein type,continental volcano-subvolcanic type and skarn type,respectively.The supergiant deposits include the Shuangjianzishan deposit(silver metal amount of 15214 t with average grade of 138 g/t),the Baiyinchagandongshan deposit(silver metal amount of 9446 t with average grade of 187 g/t),the Huaobaote deposit(silver metal amount of 6852 t with average grade of 170 g/t),and the Fuxingtun deposit(silver metal amount of 5240 t with average grade of 196 g/t).The silver deposits are mainly distributed in the central and south of the Daxing’anling area,and mainly formed in the Yanshanian period.The silver polymetallic deposits in the Daxinganling area are significantly controlled by regional faults and the junction zone of volcanic rock basins and their margins.The north-east trending deep faults are the most important ore-controlling structures in this area.The distribution of silver polymetallic deposits along the main faults is obvious,and the intersection area of multiple groups of faults often form important mine catchments.The Permian is the most important ore-bearing formation in this area,but some important silver polymetallic deposits occur in Mesozoic volcanic basins or pre-Mesozoic strata.The magmatic rocks related to mineralization are mainly intermediate acidic or acidic intrusions,intermediate acidic lavas,pyroclastic rocks,and small intrusions of ultra-shallow or shallow facies of the Yanshanian Period.The mineralization element combination is mainly determined by the elemental geochemical background of surrounding rocks or source layers.In addition,the type of deposit,the distance from the mineralization center,and the degree of differentiation of ore-forming rock mass are also important influence factors.The article analyzes the prospecting prospects of each silver deposit type in the study area,discusses the relationship between mineralization center and deep prospecting,and proposes that porphyry silver deposits should be paid attention to.In the prospecting and exploration of silver deposits,comprehensive evaluation and multi-target prospecting need to be strengthened because silver can coexist or be associated with a variety of metals.
文摘The?Annage gold deposit is located at the east part of the eastern Kunlun orogenic belt. The characteristics of ore-forming fluids and metallogenesis were discussed by using fluid petrography, micro-thermometry and hydrogen-oxygen isotope analysis. Three stages, namely quartz-pyrite stage (A), quartz-polymetallic-sulfide stage (B) and quartz-ankerite stage (C) were included in the hydrothermal process as indicated by the results of this study. Inclusions developed in ore-bearing quartz veins from stages A and B are of three types: aqueous inclusions (type I), CO2-bearing inclusions (type II) and pure CO2?inclusions (type III). All three types of inclusions, mainly type I, are presented in stage A, having homogenization temperatures at 180°C - 360°C, and salinities ranging from 0.53% to 21.44%. In addition to development of type I inclusions, type II and III inclusions increase significantly in stage B, with homogenization temperatures ranging from 160°C to 330°C, and salinities are from 1.32% to 22.01%. Based on micro-thermometry, fluids in Annage deposit are of H2O-NaCl-CO2?type with medium-high temperature (140°C - 395°C) and medium-low salinity (0.53% - 22.01%). Results of hydrogen-oxygen isotope analysis show that ore-forming fluid is mainly CO2-rich magmatic fluid, mixed with shallow groundwater or metamorphic hydrothermal in the late mineralization stages. Calculated metallogenic pressures are in the range of 79 - 130MPa corresponding to a maximum depth of 4.8 km. The Annage deposit is a mesothermal quartz vein type gold deposit.
文摘The Lamasu copper polymetallic mineralized region lies in the south of Wenquan County, Xinjiang and in the Northwest lakeside of the Sailimu Lake. Seen from the geotectonic position, it belongs to North Tianshan geodome system, Tianshan diwa region, Central Asian crustobody. Copper and zinc polymetallic ore bodies had been formed in the skarn of the contact, between the metamophic carbonate rocks of the Kuximqiek Group, Jixian System and early mid Varisean acidic rockbodies. The formation of the ore deposit was the result of the successive activities of the crust and mantle and the tectonic and magmatic activities.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC2905001)the National Natural Science Foundation of China(Grant Nos.42272093,42230813)a geological survey project(Grant No.DD20230054).
文摘The Jiama deposit,a significant porphyry-skarn-type copper polymetallic deposit located within the Gangdese metallogenic belt in Tibet,China,exemplifies a typical porphyry metallogenic system.However,the mineral chemistry of its accessory minerals remains under-examined,posing challenges for resource assessment and ore prospecting.Utilizing electron microprobe analysis and LA-ICP-MS analysis,this study investigated the geochemical characteristics of apatite in ore-bearing granite and monzogranite porphyries,as well as granodiorite,quartz diorite,and dark diorite porphyries in the deposit.It also delved into the diagenetic and metallogenic information from these geochemical signatures.Key findings include:(1)The SiO_(2) content,rare earth element(REE)contents,and REE partition coefficients of apatite indicate that the dark diorite porphyry possibly does not share a cogenetic magma source with the other four types of porphyries;(2)the volatile F and Cl contents in apatite,along with their ratio,indicate the Jiama deposit,formed in a collisional setting,demonstrates lower Cl/F ratios in apatite than the same type of deposits formed in a subduction environment;(3)compared to non-ore-bearing rock bodies in other deposits formed in a collisional setting,apatite in the Jiama deposit exhibits lower Ce and Ga contents.This might indicate that rock bodies in the Jiama deposit have higher oxygen fugacity.Nevertheless,the marginal variation in oxygen fugacity between ore-bearing and non-ore-bearing rock bodies within the deposit suggests oxygen fugacity may not serve as the decisive factor in the ore-hosting potential of rock bodies in the Jiama deposit.
文摘The Wangfeng gold deposit is one of the five most important gold deposits in the Tian-shan. Studies of its metallogenic time, space, geodynamic background, ore feature and ore fluid have proved that the deposit formed in the late Paleozoic continental collision, and consequently is a suitable delegate to probe mineralizing regularities during collisiona! orogenesis. Isotopic studies including O, D, C, S, Pb and Sr reveal ore materials derived from sedimentary association (including carbonate and sulfate), which further refers to the Hercynian carbonate-silicolite-argillite formation north to Wangfeng camp. At the end of Paleozoic, the southward intracontinental subduction of Hercynian synthem along the Hongwuyueqiao fault down to the Central Tianshan terrane induced large-scale fluidization which extracted and out-transported ore materials from Hercynian synthem upto shallow fair positions, and finally resulted in the formation of the Wangfeng deposit. This study excludes the possibility of other
基金supported by the National Natural Science Foundation of China (Grant Nos. 41472067, 41772088, 41320104004, 41773042, 41773043)the China Geological Survey (Grant No. DD20160024)
文摘Modern collisional orogens represent the natural laboratory for the study of metallogeny in continental collision zones. The Pyrenees, Alps, Zagros and Himalaya are all associated with Neo-Tethyan subduction and represent the youngest collisional orogens on Earth. Here, we compare these four orogens in terms of their composition, architecture, tectonic evolution,and metallogenic systems. The four orogens can be divided into simple and composite types. Simple orogens are represented by the Pyrenees and the Alps, and are characterized by narrow linear shapes in plain view and symmetric structures in cross-section,are free of arc magmatism, and are associated with the Mississippi Valley Valley-type Pb-Zn and orogenic gold deposits. The mineral deposits that form in these simple collisional orogens are generally related to processes that occur in the middle and upper crust. In contrast, composite orogens, as exemplified by the Zagros-Iranian and Himalayan-Tibetan Plateaus, are associated with broad orogenic plateaus in plain view and asymmetrical structures in cross-section, record extensive arc magmatism in continental margins, and are associated with a variety of deposit types including carbonatite-related rare earth element(REE),porphyry Cu-Mo, orogenic Au, Mississippi Valley type Pb-Zn, and detachment-fault-related polymetallic deposits. Although the subduction of Neo-Tethys oceanic crust occurred before the creation of simple collisional orogens in the Pyrenees and the Alps,these areas do not show the record of continental arc magmatism. In contrast, the composite collisional orogens are associated with the development of huge continental margin arcs prior to continental subduction, and the subduction was followed by reactivation of the subduction-modified arc lithospheric material, generating the ore-forming systems in these regions.
基金supported by the National Key R & D Program of China (Grant No. 2017YFC0601201)the National Natural Science Foundation of China (Grant Nos. 41888101, 41730210, 41672219)the IGCP662 Project
文摘As one of the largest Phanerozoic orogens in the world,the Central Asian Orogenic Belt(CAOB)is a natural laboratory for studies of continental dynamics and metallogenesis.This paper summarizes the research progresses of the accretionary processes and metallogenesis of the CAOB since the Peopled Republic of China was founded,and puts forward the prospect for future research.During the early period(1950s-1970s),several geological theories were applied to explain the geological evolution of Central Asia.In the early period of China's reform and opening-up,the plate tectonics theory was applied to explain the evolution of the northern Xinjiang and Xingmeng regions,and the opinion of subduction-collision between Siberian Kazakhstan and China-North Korea-Tarim plates was proposed.The idea of the Solonker-Yanbian suture zone was established.In the 1990s,the study of the CAOB entered a period of rapid development.One school of scholars including geologists from the former Soviet Union proposed a multi-block collision model for the assemblage of the CAOB.In contrast,another school of scholars,led by a Turkish geologist,Celal Sengor,proposed that the Altaids was formed through the growth and strike-slip duplicates of a single island arc,and pointed out that the Altaids is a special type of collisional orogen.During this period,Chinese geologists carried out a lot of pioneering researches on ophiolites and high-pressure metamorphic rocks in northern China,and confirmed the main suture zones accordingly.In 1999,the concept of"Central Asian metallogenic domain"was proposed,and it became one of the three major metallogenic domains in the world.Since the 21st century,given the importance for understanding continental accretion and metallogenic mechanism,the CAOB has become the international academic forefront.China has laid out a series of scientific research projects in Central Asia.A large number of important scientific research achievements have been spawned,including the tectonic attribution of micro-continents,timing and tectonic settings of ophiolites,magmatic arcs,identification and anatomy of accretionary wedges,regional metamorphism-deformation,(ultra)high-pressure metamorphism,ridge subduction plume-plate interaction archipelagic paleogeography and spatio-temporal framework of multiple accretionary orogeny,continental growth accretionary metallogenesis,structural superposition and transformation etc.These achievements have made important international influences.There still exist the following aspects that need further study:(1)Early evolution history and subduction initiation of the Paleo-Asian Ocean;(2)The accretionary mechanism of the extroversion Paleo-Asian Ocean;(3)The properties of the mantle of the Paleo-Asian Ocean and their spatiotemporal distribution;(4)The interaction between the Paleo-Asian Ocean and the Tethys Ocean;(5)Phanerozoic continental growth mechanism and its global comparison;(6)Accretionary metallogenic mechanism of the Central Asian metallogenic domain;and(7)Continental transformation mechanism.
基金supported by the National Climbing Program of China(Grant No.95-Y-25)the National Natural Science Foundation of China(Grant Nos.40273019 and 40172028)+1 种基金the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant Nos.KZCX2-102 and KZCX2-SW-117)the Major State Basic Research Program of China(Grant No.G1999043202).
文摘Many of the Yanshannian intermediate-acid intrusive rocks related to Cu-Au mineraliza-tion in the Eastern Yangtze Block are characterized by high AI2O3, Sr contents, while low in Y, Yb contents, thus with high Sr/Y, and La/Yb ratios, and variational isotope signatures in particular, e.g. εNd(t) = -11.92-1.96, (143Nd/144Nd): = 0.5120-0.5125, TDM= 0.70-1.71 Ga, (7Sr/86Sr), = 0.7043 -0.7076. The geochemical characteristics of these rocks suggest that: (1) these rocks are geo-chemically similar to adakite, which might have been stemmed from the partial melting of thick-ened basaltic lower crust due to basalt underplating; and (2) the high pressure (1.2-4.0 GPa) and high temperature (850-1150℃) surroundings of the lower crust favor both the fluid and ada-kite-like magma to generation. Not only can the adakite-like magma carry abundant fluid and Cu-Au ore-froming materials, but also can it bring them to the shallow part with ease and contrib-utes to the Cu-Au mineralization.
基金supported by the National Natural Science Foundation of China for Distinguished Young Scholars(Grant No.41725009)the“135”Planned Project of Guangzhou Institute of Geochemistry,Chinese Academy of Sciences(Grant No.135PY201606)the Strategic Priority Program of the Chinese Academy of Sciences(Type B)(Grant No.XDB18030206)。
文摘Porphyry copper±molybdenum±gold deposits(PCDs) are the most representative magmatic-hydrothermal metallogenic system above subduction zones with important economic value. Previous studies revealed that large PCDs are generally formed from initial arc magmas(from subduction-induced partial melting of the mantle wedge), which eventually ascend to the shallow crust(3–5 km) for mineralization after a series of complex evolution processes. These processes include(1) the dehydration or partial melting of subducting slab, which induces partial melting of the metasomatized mantle wedge;(2)the ascent of mantle-derived magma to the bottom of the lower crust, which subsequently undergoes crustal processes such as assimilation plus fractional crystallization(AFC) or melting, assimilation, storage and homogenization(MASH);(3) the magma chamber formation at the bottom of the lower, middle and upper crust;(4) the final emplacement and volatilization of porphyry stocks;and(5) the accumulation of ore-forming fluids and metal precipitation. Despite the many decades of research, many issues involving the PCD metallogenic mechanism still remain to resolve, such as(1) the tectonic control on the geochemical characteristics of ore-forming magma;(2) the reason for the different lifespans of the long-term magmatic arc evolution and geologically "instantaneous" mineralization processes;(3) the source of ore-forming materials;(4) the relative contributions of metal pre-enrichment to mineralization by the magma source and by magmatic evolution;and(5) the decoupling behaviors of Cu and Au during the pre-enrichment. These issues point out the direction for future PCD metallogenic research, and the resolution to them will deepen our understanding of the metallogenesis at convergent plate boundaries.
基金supported by the National Basic Research Program of China(Grant No.2012CB416800)。
文摘The predominant types of high-grade iron deposits in China include skarn,sedimentary metamorphic(banded ironformation,BIF-type),continental/submarine volcanic-hosted and magmatic Fe-Ti-Voxide deposits.Based on a comprehensive review of current studies on these deposits,this paper suggests that the oxygen concentration in atmosphere played an important role for the formation of BIFs,whereas the tectonic setting and deep magmatic differentiation processes are more important for the other types.Notably,both high temperature and high pressure experiments and melt inclusion studies indicate that during the differentiation,high temperature magmas could develop iron-rich magma via liquid immiscibility but not pure oxide melt("iron ore magma").Fe-P melt could be generated directly by liquid immiscibility under hydrous and oxidized condition.The formation of high-grade iron deposits is mostly associated with the processes related to multiple stages of superimposition,e.g.,desiliconization and iron enrichment,removal of impurity,and remobilization and re-precipitation of iron.According to the temporal evolution,the high-grade iron deposit could be divided into multi-episode superimposition type(temporally discontinuous mineralization)and multi-stage superimposition type(temporally continuous mineralization).The former is represented by the sedimentary metamorphic iron deposit,and the latter includes those related to magmatic-hydrothermal fluids(e.g.,skarn,volcanic-hosted and magmatic types).
文摘Mesozoic volcanic rocks are widely distributed in southeastern China. There exist various kinds of subvolcanic granitoids associated with the volcanic rocks. This paper deals with the geological setting, the characteristics and the metallogenesis of these subvolcanic granitoids.
文摘EPITHERMAL gold (copper) deposits distributed in the middle-south parts of Tancheng-Lujiang deep faultzone and its vicinity have close relation to Mesozoic shoshonitic magmatism. According to their metallogenic features and ore-forming conditions, these deposits can be divided into three types; tellurium-goldtype Au deposit, quartz-adularia type Au deposit and quartz-manganoansiderite type Au-Cu deposit. Therepresentative deposits of them are Guilaizhuang, Dongxi and Tiantoushan. In this note, the general features of the three typical epithermal gold (copper) deposits are outlined and the relationship between mineralization and types of volcanic basins is discussed preliminarily.
文摘1 Geology Daolundaba copper polymetallic deposit occurs in West Ujimqin Banner,the Xilin Gol League of Inner Mongolia,along the west side of South part of Daxinganling ore belt,whose tectonic position just lies at the junction of Siberian Block in the south part,North China Block in the north and Songliao block in the east.The Daolundaba copper polymetallic deposit is hosted by the Lower Proterozoic Baoyintu group of biotite-plagioclase gneiss(Pt1by),upper Permian Linxi formation of sandy slate(P2l),and the Hercynian Qianjinchang pluton of biotite granite.
基金provided by the Opening Foundation of State Key Laboratory of Continental Dynamics(Grant No.21LCD08),Northwest University,China.
文摘The Dongnan Cu–Mo deposit,located in the southeast of the Zijinshan ore field(the largest porphyry–epithermal system in Southeast China),represents the complex magmatic and metallogenesis events in the region.The petrogenesis and metallogenesis of granitoids from the deposit are not determined,especially the interactions between ore-bearing(granodiorite porphyry)and barren samples(granodiorite and diorite).In the paper,the whole rock geochemical features shared a similar affinity to the middle-lower content and revealed that they derived from partial melting of the Cathaysian basement with the contribution of mantle materials,even represented that they generated in the plate subduction;LA-ICP-MS zircon U–Pb ages show that these granodiorites,granodioritic porphyry and diorite,were generated during 114–103 Ma.The ore-bearing samples mostly presented ε_(Hf)(t)of negative values(peak value is-4 to-3)with old two-stage Hf model ages(t_(DM)^(2))(peak value is 1.10–1.15 Ga),while the barren sample showed slightly negative ε_(Hf)(t)(peak value is-1 to 0)values with young t_(DM)^(2)(peak value is 1.00–1.05 Ga).The value of zircon Ce^(4+)/Ce^(3+)ratio mostly higher than 450 was first verified for the ore-bearing samples in the Dongnan Cu–Mo deposit,and the values of ore-bearing were found to be higher than those from the barren,which suggests that the ore-bearing formed in more oxidized parental magma with higher oxygen fugacity.Based on the geochemical characteristic of the element and isotope,we concluded that the Early Cretaceous multiphases magmatic activities,low melting temperature and low pressure of pluton,and high oxygen fugacity of zircon,were the favorable conditions for metallogenesis of Dongnan Cu–Mo deposit.
基金financially supported by the National Basic Research Program of China (No. 2015CB452605)the Natural Science Foundation of China (No. 41602089)Fundamental Research Funds for the Central Universities (No. 20170713174019)
文摘The newly-discovered Donglufang Moe Cu porphyry-skarn deposit is located in the southern Yidun Terrane, southeast Tibet, with more than 80 million tonnes(Mt) of reserves(grading 0.15 wt.% Mo and0.48 wt.% Cu) hosted in Triassic strata and Late Cretaceous granodiorite porphyry. Ree Os dating of molybdenum ore yielded a weighted mean age of 84.9 ± 1.0 Ma and an isochron age of 85.2 ± 0.6 Ma.LA-ICP-MS Ue Pb dating of zircons from the granodiorite porphyry yielded206 Pb/238 U ages ranging from 87.4 Ma to 84.2 Ma with a weighted mean206 Pb/238 U age of 85.1 ±0.5 Ma, indicating a temporal linkage between granitic magmatism and Moe Cu mineralization. Geochemical analyses show that the granodiorite porphyries are I-type granites with Si O_2 contents of 64.3 -66.7 wt.%. These rocks are typically metaluminous with high K_2 O/Na_2 O ratios, low Mg O(1.32 -1.56 wt.%), Cr(5.6 -12.9 ppm), Ni(3.79 -10.81 ppm), Mg#(43 -52) values, and high Sr(304 -844 ppm), Sr/Y(21.2 -50.8) and La/Yb ratios(37.0 -60.1). They are enriched in light rare-earth elements(LREE) relative to heavy rare-earth elements(HREE), with slightly negative Eu anomalies, and are enriched in Th, U and large ion lithophile elements(LILE, e.g., K and Rb), and depleted in high field strength elements(HFSE, e.g., Nb, Ta, P and Ti). They also show negative zircon εHf(t) values(-6.7 to -2.3) and negative whole rock εNd(t) values(à5.2 to-4.3), as well as old Hfe Nd model ages, indicating the magmas were derived from a thickened ancient lower crust within the garneteamphibolite facies. Considering the tectonic evolution of the Yidun Terrane, geochemical characteristics of granodiorite porphyry, and the ages of mineralization obtained in this study. We suggest that the Donglufang deposit was formed in a post-collisional setting, which has a genetic relationship with the emplacement of the granodiorite porphyry. The present study provide key information for the exploration of the Late Cretaceous metallogeny in the Yidun Terrane.
基金granted by the National Key R & D Program of China (2017YFC0601200), which is greatly acknowledged
文摘The Altai-Junggar-Tianshan collage in southern Altaids is an important metallogenic domain in Central Asia that contain world-class copper-iron-nickel deposits.As an accretionary-type metallogenic system,the metallogenic processes of the Altai-Junggar-Tianshan collage is essential in understanding the genetic mechanism of ore deposits in general.Here in this paper we present a brief introduction to the project on the western part of the Southern Altaids,entitled"The deep structure and metallegenic processes of the North China accretionary metallogenic systems".This project mainly focuses on the deep structure and metallogenic background of the Altai-Junggar-Tianshan collage by integrated studies from field geology,structural mapping,geochemistry and geophysical exploration.Multiple new geological and geophysical methods will be applied to make transparency of the Kalatongke and Kalatage ore clusters.This will update our understanding of the geodynamic processes of metallogenesis and lead to the development and foundation of new metallogenic theories in accretionary orogens.
