Beijing Institute of Geology for Mineral Resources

Beijing, China

Beijing Institute of Geology for Mineral Resources

Beijing, China

Time filter

Source Type

Deng X.-H.,Beijing Institute of Geology for Mineral Resources | Deng X.-H.,Peking University | Chen Y.-J.,Peking University | Santosh M.,China University of Geosciences | And 2 more authors.
Gondwana Research | Year: 2016

The Zhifang Mo deposit is located in the northeastern Qinling Orogen along the southern margin of the North China Craton. The deposit represents a quartz-vein system hosted in the Mesoproterozoic Xiong'er Group volcanic rocks. We identify three hydrothermal stages (early, middle and late), characterized by veinlets of quartz-pyrite, quartz-molybdenite-pyrite-chalcopyrite-galena-sphalerite, and quartz-carbonate assemblages, respectively. Five molybdenite samples from the Zhifang deposit yield Re-Os ages ranging from 241.2 ± 1.6 Ma to 247.4 ± 2.5 Ma, with an isochron age of 246.0 ± 5.2 Ma (2σ, MSWD = 7.4), and a weighted mean age of 243.8 ± 2.8 Ma (2σ, MSWD = 5.5). The Re-Os age shows that the Mo mineralization occurred during the Indosinian Orogeny, and suggests that the mineralization is unrelated to the Yanshanian magmatism or the Paleo-Mesoproterozoic volcanic-hydrothermal event. This study also reports a new Sr-Nd-Pb isotope dataset from ore sulfides in an attempt to constrain the source of the ore-forming fluids. Ten sulfide samples from middle stage of the Zhifang Mo deposit yield ISr(t) ratios of 0.710286-0.711943, with an average of 0.711004; εNd(t) values between -19.5 and -14.8, with an average of -16.7; and (206Pb/204Pb)i, (207Pb/204Pb)i and (208Pb/204Pb)i ratios of 17.126-17.535, 15.374-15.466 and 37.485-37.848, with averages of 17.380, 15.410 and 37.631, respectively. One pyrite from the early stage yield ISr(t) of 0.722711-0.722855, with an average of 0.722783, which is higher than those of the middle stage sulfides and suggests equilibration with wallrocks. The εNd(t) values are in the range of -17.3 to -16.6 with a mean at -17.0; and (206Pb/204Pb)i, (207Pb/204Pb)i and (208Pb/204Pb)i ratios are 17.386, 15.405 and 37.622, respectively. The ore sulfides show higher Pb-isotope ratios, higher εNd(t) and lower ISr(t) values than the host rocks. The results suggest that the ore-forming fluids had lower ISr(t), and higher εNd(t) values than the ore sulfides, and were possibly sourced from the Dengfeng Complex. The southward subduction of the North China Craton beneath the Huaxiong Block during the Triassic was possibly responsible for the formation of the Waifangshan orogenic Mo system. © 2015 International Association for Gondwana Research.


Wang Z.Y.,Tsinghua University | Qi L.,Sichuan Agricultural University | Wang X.,Beijing Institute of Geology for Mineral Resources
Natural Hazards | Year: 2012

Large-volume debris flow events are defined when the volume of solid materials exceeds 1 million m 3. Traditional engineering measures, such as check dams, diversion channels, and flumes, are effective for normal debris flow control but are not sufficient to control large-volume debris flows. Experiments were conducted with an artificial step-pool system on the new Wenjiagou Gully to mitigate large-volume debris flows. The old Wenjiagou Gully was buried by 81.6 million m 3 of loose solid material created by a landslide that was triggered by the Wenchuan earthquake on May 12, 2008. The new gully was formed during the scouring process caused by debris flows in 2008. Large-volume debris flows were initiated by rainstorm flood with high kinetic energy. The artificial step-pool system was constructed with huge and big boulders on the new Wenjiagou Gully in 2009. The step-pool system dissipated flow energy in steps and hydraulic jumps. Analysis proved that the step-pool system dissipated two-third of the kinetic energy of flow; thus, the critical discharge for triggering debris flow increased threefold. Due to the step-pool system maximized the flow resistance and protected the bed sediment and banks from erosion, the rainstorm floods in 2009 did not trigger debris flows. In 2010, the step-pool system was replaced with 20 check dams. Huge boulders were broken into small pieces of diameter less than 0.5 m and were used as building materials for the 20 dams. Without the protection of the step-pool system, a rainstorm flood scoured the base of the dams and caused failures for all of the 20 check dams in August 2010. The flow incised the gully bed by 50 m. The loose bank materials slid into the flow mixed with water and formed a large-volume debris flow with a volume of 4. 5 million m 3. Many houses were buried by the debris flow, and 12 people were killed. Comparison of the two strategies proved that energy dissipation structures are necessary for controlling large-volume debris flows. Check dams, if they are stable, may reduce the potential of bank failures and control debris flows. The step-pool system dissipates flow energy and control gully bed incision and bank failure. A combination of check dams and step-pool systems may be the most effective for mitigating debris flows. © 2011 Springer Science+Business Media B.V.


Yue S.-W.,South China University of Technology | Yue S.-W.,CAS Guangzhou Institute of Geochemistry | Deng X.-H.,Beijing Institute of Geology for Mineral Resources | Deng X.-H.,Peking University | Bagas L.,University of Western Australia
Geological Journal | Year: 2014

The Yindonggou Ag-Au(-Pb-Zn) deposit is hosted by metamorphosed volcanic rocks of the ca. 740-760Ma Wudangshan Group in the Proterozoic Wudang Block of the southern part of the Qinling Orogen, central China. The deposit consists of a series of mineralized quartz veins located in the Yindongyan Anticline. Based on the mineral assemblages and cross-cutting relationships of quartz veins, the deposit can be divided into: (1) early fine-grained quartz-sphalerite-galena veins; (2) fine-grained quartz-silver-gold veins containing minor amounts of pyrite; (3) coarse-grained quartz veins with minor amounts of galena, sphalerite, and chalcopyrite; and (4) late ankerite-quartz veins. Most of the Pb-Zn mineralization formed during the early (Stage 1) veins followed by the deposition of Ag-Au mineralization in the Stage 2 veins. The δ18O value for the ore-forming fluids decreases from 6.6-9.4‰ in the Stage 1 veins through 3.6-4.9‰ in the Stage 2 veins to -1.2‰ to 0.4‰ in the Stage 3 veins (the δ18O values could not be determined for the Stage 4 veins). Furthermore, the δD values are -74‰ for the Stage 1 veins, -95‰ to -56 ‰ for the Stage 2 veins, and -48‰ to -73‰ for the Stage 3 veins. The δ13C values for ankerite in the Stage 4 veins are between -2.9‰ and -1.1‰. The δD vs. δ18OH2O plot for these values indicates that there was a shift from metamorphic fluids during the formation of the early veins to meteoric fluids during the formation of the later veins at the deposit. The H-O-C isotope systematics also indicate that the ore fluids forming the deposit were probably initially sourced from metamorphic dehydration of volcanic-carbonate rocks in the ca. 740-760Ma Wudangshan Group and with time gradually mixed with meteoric water by Stage 4. The δ34S values for sulphides from the deposit range from -0.9‰ to 7.1‰ in the Stage 1 veins, 3.8‰ to 5.0‰ in the Stage 2 veins, and 2.4‰ to 11.3‰ in the wallrocks. Sulphides from the mineralized Stage 1 veins yield 206Pb/204Pb ratios of 16.44-16.6, 207Pb/204Pb ratios of 15.25-15.5, and 208Pb/204Pb ratios of 36.4-36.98. Five pyrite samples from the Stage 2 veins yield 206Pb/204Pb ratios of 16.475-16.529, 207Pb/204Pb ratios of 15.346-15.395, and 208Pb/204Pb ratios of 36.49-36.616. Both the S and Pb isotope ratios are between the ratios for units in the Wudangshan Group and mantle but differ from other lithological units in the Wudang Block, which suggest that the mineralized fluids interacted with both the Wudangshan Group and deep-seated sources. Thus, we suggest that the original ore-forming fluids are metamorphic in origin, and the metal deposition resulted from fluid mixing. From the characteristics observed, the Yindonggou Ag-Au(-Pb-Zn) deposit can be classified as an orogenic-type deposit generated during the Triassic Qinling Orogeny resulting from northward oceanic plate subduction along the Mian-Lue Suture. © 2014 John Wiley & Sons, Ltd.


Wang Z.-Y.,Tsinghua University | Qi L.-J.,Sichuan Agricultural University | Wang X.-Z.,Beijing Institute of Geology for Mineral Resources
Shuili Xuebao/Journal of Hydraulic Engineering | Year: 2012

Experiments were conducted with an artificial step-pool system on the new Wenjiagou Gully to mitigate large volume debris flows in 2009. The step-pool system dissipated flow energy in steps and hydraulic jumps. Analysis proved that the step-pool system dissipated 2/3 of the kinetic energy of flow, thus the critical discharge for triggering debris flow increased threefold. Due to the step-pool system maximized the flow resistance and protected the bed sediment and banks from erosion, the rainstorm floods in 2009 did not trigger debris flows. In 2010 the step-pool system was replaced with 20 check dams. Huge boulders were broken into small pieces of diameter less than 0.5 m and were used as building materials for the 20 dams. Without the protection of the step-pool system, a rainstorm flood scoured the base of the dams and caused the failure of check dams in Aug. 2010. The flow incised the gully bed by 50 m. The loose bank materials slid into the flow mixed with water and formed a large volume debris flow with a volume of 4.5 million m. Many houses were buried by the debris flow and 12 people were killed. Comparison of the two strategies proved that energy dissipation structures are necessary for controlling large volume debris flows. Check dams, if they are stable, may reduce the potential of bank failures and control debris flows. The step-pool system dissipates flow energy and control gully bed incision and bank failure. A combination of check dams and step-pool systems may be the most effective for mitigating debris flows.


Li N.,Peking University | Chen Y.-J.,Peking University | Deng X.-H.,Peking University | Deng X.-H.,Beijing Institute of Geology for Mineral Resources | Yao J.-M.,CAS Guangzhou Institute of Geochemistry
Ore Geology Reviews | Year: 2014

The 1.85. Ga Longmendian Mo deposit in East Qinling is the oldest Mo system recognized in China. It is unique for three reasons: (1) quartzofeldspathic orebodies are away from any intrusion or fault, (2) it is closely associated with migmatitic rocks, and (3) it has remarkably high Re content in molybdenite (504 to 1660. ppm). The origin of the deposit is poorly constrained.In the Longmendian deposit, strong Mo mineralization is always associated with hydrothermally altered migmatitic amphibolites. To probe into ore genesis, detailed fluid inclusion studies are carried out on both mineralized migmatitic amphibolites and ore-barren rocks. Four compositional types of fluid inclusions are observed, including CO2±CH4 (PC-type), CO2-H2O (C-type), daughter mineral-bearing (S-type) and H2O-NaCl (W-type). Quartz in mesosome and melanosome of mineralized migmatitic amphibolites contains all of the four types of inclusions. Measurements of immiscible inclusion assemblages in the ores constrain the Mo-mineralization temperatures and pressures to be 225-390°C and 114-265MPa, respectively. Primary fluid inclusions in barren migmatitic gneisses are dominated by S-type, and minor of C- and PC-types which are identical to those in the leucosome of migmatitic amphibolites. These inclusions yield lower homogenization temperatures than those in the mineralized mesosome and melanosome of migmatitic amphibolites, suggesting that the ore-causative, injected melts should have higher temperatures and originated from depths. Such features of the ore-forming fluids indicate that the Longmendian deposit was a migmatitic-hydrothermal system caused by high-temperature melt injection. This interpretation can also be supported by the observations below: (1) tourmaline is abundant in melanosome, but absent in mesosome; (2) the consistent quartzofeldspathic composition of leucosome is independent of mesosome; (3) leucosome in migmatitic amphibolite crosscuts each other; (4) halite-bearing fluid inclusions are prevalent in studied samples, which is the feature of granitic rocks, instead of the scenarios of in situ migmatites; and (5) the trapping temperatures of fluid inclusions in mineralized migmatitic amphibolite are much lower than those required for partial melting, but higher than those obtained from barren migmatitic rocks. © 2014 Elsevier B.V.


Deng X.-H.,Peking University | Deng X.-H.,Beijing Institute of Geology for Mineral Resources | Santosh M.,China University of Geosciences | Yao J.-M.,CAS Guangzhou Institute of Geochemistry | Chen Y.-J.,Peking University
Geological Journal | Year: 2014

The East Qinling region in central China, hosting several tens of Mesozoic magmatic-hydrothermal Mo deposits, is one of the largest molybdenum belts in the world. The Zhifang Mo deposit is hosted in volcanic rocks of the Xiong'er Group in the Waifangshan area, Qinling Orogen. Previous studies variously correlated the mineralization in this deposit with Yanshanian magmatism or Palaeo-Mesoproterozoic volcanic-hydrothermal events. The orebodies are associated with quartz veins and controlled by subsidiary faults of the Machaoying Fault. The ore-forming process can be divided into the early, middle and late stages and is characterized by quartz-pyrite, quartz-polymetallic sulphide and quartz-carbonate veins, respectively. The early-stage quartz is structurally deformed, suggesting a compressional tectonic regime; the middle-stage sulphides fill the fractures of the early-stage assemblages and show no deformation, suggesting a tensional setting; the late-stage veins mostly infill the open-space fissures. Three types of fluid inclusions (FIs) are identified at the Zhifang deposit: H2O-NaCl (W-type), CO2-rich (C-type) and daughter mineral-bearing inclusions (S-type). Fluid inclusions of early-stage quartz homogenize between 380 and 470°C, with salinities ranging from 0.4 to 9.6wt.% NaCl equiv., whereas the late-stage calcite contains only the W-type FIs with homogenization temperatures of lower than 240°C, and salinities of 0.4-8.7wt.% NaCl equiv. This indicates that the ore fluid system evolved from CO2-rich, probably metamorphic hydrothermal to CO2-poor, meteoric fluid. All three types of FIs can be observed in the middle-stage quartz, and even in the microscopic domain of a crystal, suggesting that this heterogeneous association was trapped from a boiling fluid system. These FIs homogenized at temperatures ranging from 250 to 360°C and display two salinity clusters of <18.5 and 29.1-29.9wt.% NaCl equiv. These results suggest that metal precipitation resulted from fluid boiling. The estimated trapping pressures of FIs range from 101 to 285MPa, suggesting an alternating lithostatic-hydrostatic fluid system, which was controlled by a fault-valve at the depth of 10km. The δ34S values of ore minerals from the Zhifang Mo deposit show a range between -11.8‰ and 6.0‰, with a bimodal distribution. The early-stage pyrite has a positive δ34S value of 6.0‰ that is similar to the host rocks of the Xiong'er Group and the Taihua Supergroup, suggesting that the wall rocks contributed much of the sulphur to the early-stage pyrite during fluid-rock interaction. However, the δ34S values of the middle-stage sulphides have negative mean and restricted range from -11.8‰ to -4.5‰. The widespread rutile grains coexisting with molybdenite in the middle-stage correlate the negative δ34S values with relatively oxidized fluids. We consider phase separation as an efficient mechanism for ore-fluid oxidation and molybdenum deposition based on fluid inclusions and sulphur isotope data. Geological, fluid inclusion and sulphur isotope data of the Zhifang Mo deposit suggest that the Mo mineralization is unrelated to the Yanshanian magmatism or the Palaeo-Mesoproterozoic volcanic-hydrothermal event. Here we propose that the Zhifang Mo deposit may be considered as an orogenic mineral system, with its formation in an active continental margin related to the northward subduction of the Mian-Lue oceanic plate during the Triassic. © 2014 John Wiley & Sons, Ltd.


Mao Q.,Beijing Institute of Geology for Mineral Resources | Mao Q.,CAS Institute of Geology and Geophysics | Xiao W.,CAS Institute of Geology and Geophysics | Fang T.,Beijing Institute of Geology for Mineral Resources | And 4 more authors.
Gondwana Research | Year: 2012

We report newly-defined Nb-enriched basalts, adakites and dacites from the Beishan, NW China of the southern Altaids based on field, geochemical, isotopic and geochronology studies. Two phases of adakites (adakite-I and adakite-II) have been defined, which are calc-alkaline, and characterized by high Na 2O/K 2O ratios (1.49-1.71 and 2.32-3.64) and Sr contents (494-1213ppm and 325-494ppm), negligible to positive Eu anomalies, strong depletion of HREE (e.g., Yb=0.48-0.93ppm and 0.50-0.99ppm) and Y (6.87-9.80ppm and 6.02-10.30ppm), and enriched in Rb, Sr, Ba, K and depleted Nb and Ti. They are characterized by relatively low ε Nd(t) values (-0.8 to -0.9 and +0.6 to +3.8) and relatively constant high ( 87Sr/ 86Sr) i ratios (0.70635-0.70636 and 0.70583-0.70651). The zircons of adakite-I have relatively low ε Hf(t)(-0.8 to +2.7). The Nb-enriched basalts are sodium-rich (N 2O/K 2O=1.31-4.44), with higher TiO 2, P 2O 5, Zr and Nb contents and (Nb/Th) PM, (Nb/La) PM and Nb/U ratios than typical arc basalts. They are relatively enriched in Rb, Ba, U, Pb and K, depleted in Nb, and minor negative to positive Ba, Zr, Sr and Ti. They have low positive ε Nd(t) (+0.9 to +2.3) and relatively high ( 87Sr/ 86Sr) i (0.70556-0.70691) ratios. The dacites are typical arc magmas, with moderately enriched LILE, distinctly negative Eu, Nb, Sr and Ti anomalies. They have positive ε Nd(t) (+2.2) and relatively high ( 87Sr/ 86Sr) i (0.70786). We argue that the Liuyuan adakites were most probably related to the melting of young/hot subducted crust of the Paleo-Asian Ocean, which included tectonically-subducted radiogenic crustal material and/or inheritance from highly radiogenic oceanic crust (e.g. OIB). The Nb-enriched basalts likely resulted from mantle wedge peridotites metasomatized by adakites and/or further changed by components other than adakites (e.g., minor slab-derived fluids). Based on own zircon SIMS U-Pb dating of these key rock types, we further propose that from the late Ordovician to early Devonian, large volumes of magma consisting of late Ordovician Nb-enriched basalts (451Ma) and dacites (442Ma), late Silurian adakite-I (424Ma), early Devonian adakite-II (374Ma) and I-S-A-type granites (436Ma-380Ma), developed in the southern Altaids. Together with other geochronological data from the literature, we conclude that subducted oceanic slab-melting was frequent from 470Ma to 370Ma. Our results suggest that frequent hot (and/or young) oceanic crustal subduction and slab-melting were important mechanisms in the accretionary growth of the Southern Altaids. © 2011 International Association for Gondwana Research.


Shaofeng L.,Beijing Institute of Geology for Mineral Resources | Shuixing F.,Beijing Institute of Geology for Mineral Resources
Acta Geologica Sinica | Year: 2016

Iron oxide copper-gold (IOCG) deposits are a research focus of the current ore deposit geology, and have attracted much attention among the worldwide geologists and exploration experts due to their shallow depth, a wide variety of mineral species and large scale. This paper presents a review of the present IOCG deposits research, which includes the definition of IOCG deposits, temporal and spatial distribution, ore-forming environments, ore-forming magmatic rocks, their geological features, ore-controlling structures and ore-bearing rocks, mineralized alteration zoning, and their genesis and ore-forming process. This work also proposed the ore prospecting direction of IOCG deposits from a trinity model of metallogenic geological bodies, metallogenic structure surface and metallogenic information signs, and discussed the existing problems of the IOCG deposits research. © 2016 Geological Society of China


Han J.-S.,CAS Guangzhou Institute of Geochemistry | Yao J.-M.,CAS Guangzhou Institute of Geochemistry | Chen H.-Y.,CAS Guangzhou Institute of Geochemistry | Deng X.-H.,Beijing Institute of Geology for Mineral Resources | Ding J.-Y.,Nanjing University
Ore Geology Reviews | Year: 2014

The Shagou deposit, located in the eastern Qinling orogenic belt, central China and hosted by the Taihua Supergroup, is a large-sized Ag-Pb-Zn deposit and has proven reserves of 1.54million tons of ore with grades of 767g/t Ag, 13.24% Pb and 4.31% Zn. The ore-forming fluids have been previously interpreted as products of direct exsolution of a crystallizing magma or sudden decompression of the fluid exsolved from magma, defining the Shagou deposit as an intrusion-related system. In this study, the Shagou deposit has been identified as an orogenic type mineralization system. The hydrothermal ore-forming process can be divided into the early quartz-pyrite, middle quartz-polymetallic sulfides and late quartz-carbonate stages. Four types of fluid inclusions in quartz can be distinguished between PC, C, W and PW types. The early and middle stage quartz contains the PC, C and W type fluid inclusions, while only W and PW type fluid inclusions can be observed in the late stage quartz. In the early stage, the W type fluid inclusions homogenized at 173-369°C (concentrating at 200-240°C), with salinities ranging from 5.4 to 8.3wt.% NaCl equiv. But in the middle stage, the C and W type fluid inclusions homogenized at 112-313°C (concentrating at 180-220°C), with salinities ranging from 0.7 to 13.6wt.% NaCl equiv. In the late stage, the W type fluid inclusions homogenized at 108-253°C (concentrating at 160-200°C), with salinities ranging from 2.1 to 8.1wt.% NaCl equiv. The fluids may have experienced a boiling process or fluid mixing in the middle stage. The estimated trapping pressures of fluid inclusions in the middle stage ranged from 33 to 211MPa, corresponding to a mineralization depth from 3.3 to 7.7km. For the early stage fluids, the calculated δ18OH2O and δDH2O values are 7.5-9.1‰, -96.2 to -110.5‰, respectively. For the middle stage fluids, these two values are 1.5-5.3‰, -75.6 to -110.7‰ but change to 1.0‰ and -87‰ for the late stage, suggesting an evolution from metamorphic to meteoric in origin. In general, the Shagou Ag-Pb-Zn deposit is similar in many respects to typical orogenic type mineralization systems. © 2014 Elsevier B.V.


Huang X.-W.,Chinese Academy of science | Huang X.-W.,University of Chinese Academy of Sciences | Zhou M.-F.,University of Hong Kong | Qi L.,Chinese Academy of science | And 2 more authors.
Mineralium Deposita | Year: 2013

The Eastern Tianshan Orogenic Belt of the Central Asian Orogenic Belt and the Beishan terrane of the Tarim Block, NW China, host numerous Fe deposits. The Cihai Fe deposit (>90 Mt at 45.6 % Fe) in the Beishan terrane is diabase-hosted and consists of the Cihai, Cinan, and Cixi ore clusters. Ore minerals are dominantly magnetite, pyrite, and pyrrhotite, with minor chalcopyrite, galena, and sphalerite. Gangue minerals include pyroxene, garnet, hornblende and minor plagioclase, biotite, chlorite, epidotite, quartz, and calcite. Pyrite from the Cihai and Cixi ore clusters has similar Re-Os isotope compositions, with ~14 to 62 ppb Re and ≤10 ppt common Os. Pyrrhotite has ~5 to 39 ppb Re and ~0.6 ppb common Os. Pyrite has a mean Re-Os model age of 262.3 ± 5.6 Ma (n = 13), in agreement with the isochron regression of 187Os vs. 187Re. The Re-Os age (~262 Ma) for the Cihai Fe deposit is within uncertainty in agreement with a previously reported Rb-Sr age (268 ± 25 Ma) of the hosting diabase, indicating a genetic relationship between magmatism and mineralization. Magnetite from the Cihai deposit has Mg, Al, Ti, V, Cr, Co, Ni, Mn, Zn, Ga, and Sn more elevated than that of typical skarn deposits, but both V and Ti contents lower than that of magmatic Fe-Ti-V deposits. Magnetite from these two ore clusters at Cihai has slightly different trace element concentrations. Magnetite from the Cihai ore cluster has relatively constant trace element compositions. Some magnetite grains from the Cixi ore cluster have higher V, Ti, and Cr than those from the Cihai ore cluster. The compositional variations of magnetite between the ore clusters are possibly due to different formation temperatures. Combined with regional tectonic evolution of the Beishan terrane, the Re-Os age of pyrite and the composition of magnetite indicate that the Cihai Fe deposit may have derived from magmatic-hydrothermal fluids related to mafic magmatism, probably in an extensional rift environment. © 2013 Springer-Verlag Berlin Heidelberg.

Loading Beijing Institute of Geology for Mineral Resources collaborators
Loading Beijing Institute of Geology for Mineral Resources collaborators