Rubidium(Rb)deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites.This study investigates a newly-discovered giant Rb deposit at ...Rubidium(Rb)deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites.This study investigates a newly-discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Xizang.Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization.LA-ICP-MS U-Pb dating of zircon yielded ages of 19.1±0.2 Ma and 19.0±0.2 Ma for greisenized monzogranite and fresh monzogranite,respectively.The monzogranites are characterized as strongly peraluminous,with high contents of SiO2,Al2O3,K2O and Na2O as well as a high differentiation index.They are enriched in light rare earth and large ion lithophile elements with significant negative Eu anomalies and depleted high fieldstrength elements.Petrological and geochemical features of these ore-related monzogranites suggest that they are highly fractionated S-type granites,derived from remelting of crustal materials in a post-collisional setting.The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore-related monzogranite during the magma’s evolution.The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization.展开更多
The Huoshaoyun deposit in the Karakorum area of NW China is the world’s largest zinc-lead carbonate ore deposit.Here we investigate the genesis of the mineralization based on multiproxy investigations.The deposit con...The Huoshaoyun deposit in the Karakorum area of NW China is the world’s largest zinc-lead carbonate ore deposit.Here we investigate the genesis of the mineralization based on multiproxy investigations.The deposit contains zinc-lead carbonate and sulfide minerals,with smithsonite(Smt),cerussite(Cer),and sulfides accounting for 85%,10%,and 5%of the total lead and zinc resources,respectively.Three ore-forming stages,involving Smt,Cer,and sulfides ores were summarized.The Smt mineralization is characterized by veined,massive,and stratified Smt forming horizontal sedimentary layered ore and vertical feeder veins similar to the SEDEX-type deposits.The sulfide and Cer veins display typical hydrothermal characteristics and are superimposed on the massive Smt ores.The Smt ores show high Li,Be,Cr,Y,Ba,Nd,Yb,and Zr contents,whereas the Cer veins have extremely high Sr contents(up to 3814–9174 ppm)and low Zr contents(less than 0.01 ppm).Galena and sphalerite show higher Cd concentrations compared to Smt and Cer ores.The Smt ores differ with different spatial locations,with Smt ores formed at the vent haveδ^(66)Zn values of+0.15‰to+0.21‰,the massive Smt formed close to the vent show a value of+0.13‰,and those formed away from the vent show a value of 0.05‰,all values being close to 0.The sulfides haveδ^(66)Zn values of−0.09‰to+0.04‰.The C-O isotopes of Smt ores are similar to both altered and unaltered host limestone,suggesting that the limestone was a potential source for carbon and oxygen.Quartz with veined Smt shows magmatic signatures withδ^(18)OVSMOW of+1.14‰to+2.23‰,high Pb(115–401 ppm)and Zn concentrations(390–997 ppm),whereas quartz associated with sulfide has meteoric fluid signature with the lowestδ^(18)OVSMOW(−14‰to−10.7‰),low Pb(11.6–49.0 ppm)and Zn(18.1–72.8 ppm)concentrations.The temperature of equilibration computed based on oxygen isotope fractionation between Smt and coeval quartz indicate a dual source with that of quartz derived from an aqueous fluid,whereas the source for Smt might involve CO_(2)or HCO_(3)^(−).We trace multiple metallogenic stages for this deposit including exhalation,hydrothermal deposition,and fault-controlled sulfide vein formation.The largest orebody(III-1)preserves a 16 Mt reserve of Zn and was formed by crust-mantle interaction at ca.195 Ma in the early development of the Linjitang post-arc rift system.Fluid convection,zinc enrichment driven by granitic magma,volcanic activity,and karst alteration induced by acid rain in a lagoonal environment promoted ore enrichment.展开更多
The end-Permian mass extinction was one of the major global crises spanning the entire Early Triassic or longer.Eruptions of volcanos were one of the factors that delayed the biotic recovery after this event.Supervolc...The end-Permian mass extinction was one of the major global crises spanning the entire Early Triassic or longer.Eruptions of volcanos were one of the factors that delayed the biotic recovery after this event.Supervolcano eruptions can cause catastrophic effects on global environment,climate,and life.Here we investigate the tuff layers from Early-Middle Triassic boundary in the Yangtze Block and identify a supervolcano eruption event.The zircon U-Pb ages of the section-Langdai,section-Daijiagou and section-Longmendong tuff samples are 247.1±1.9 Ma,247.6±2.0 Ma and 247.7±1.7 Ma,respectively.These ages mark the Olenekian-Anisian boundary.The zircon grains from the tuff layers have negativeεHf(t)(-15.3 to-0.8),two-stage Hf model(TDM2)ages(1.7 to 2.2 Ga)and display high-δ18O values(mostly>10‰).Clay minerals and quartz dominate the rock composition.The whole rock compositions show that the tuff layers were derived from magma of intermediate to felsic composition,which formed by the remelting of Paleoproterozoic materials of continental crust.The volcanic eruption site is located in the Jinshajiang-Ailaoshan-Song Ma suture zone in the southwestern margin of the Yangtze Block.A combination of the closure of the Paleo-Tethys Ocean Basin and the collision of the Indochina Block and South China contributed to the eruption,which was a supervolcano eruption under the active continental margin arc settings.We speculate that this supervolcano eruption might have contributed to the delayed biotic recovery after the end-Permian mass extinction.展开更多
The Neoproterozoic evolution of the Jiangnan Orogen is important for understanding the tectonic history of South China.As a volcanic-sedimentary sequence developed in the Nanhua rift,the Banxi Group preserves the reco...The Neoproterozoic evolution of the Jiangnan Orogen is important for understanding the tectonic history of South China.As a volcanic-sedimentary sequence developed in the Nanhua rift,the Banxi Group preserves the records of important magmatic and tectonic events linked to the assembly and breakup of the Rodinia supercontinent.In this study,we report the results from whole-rock major-and trace-element concentrations,with zircon LA-(MC)-ICP-MS U-Pb ages,trace elements and Lu-Hf isotopic compositions of sandstones from the Banxi Group.The rocks are characterized by high SiO_(2)(65.88%–82.76%,with an average of 75.50%)contents,moderate(Fe_(2)O_(3)^(T)+MgO)(1.81%–7.78%,mean:3.79%)and TiO_(2)(0.39%–0.54%,mean:0.48%),low K_(2)O/Na_(2)O(0.03–0.40,mean:0.10)ratios and low Al_2O_(3)/SiO_(2)(0.11–0.24,mean:0.15)ratios.The sandstones have highΣREE contents(mean:179.1 ppm),with chondrite-normalized REE patterns similar to the upper crust and PAAS,showing enriched LREE((La/Yb)_N mean:14.85),sub-horizontal HREE curves and mild Eu(Eu/Eu^(*):0.75–0.89,mean:0.81)negative anomalies.Their geochemical characteristics resemble those of passive continental margin sandstones.Most of the zircons are magmatic in origin and yield a U-Pb age distribution with three peaks:a major age peak at 805 Ma and two subordinate age peaks at 1990 Ma and 2470 Ma,implying three major magmatic sources.The Neoproterozoic zircons haveε_(Hf)(t)values ranging from-47.4 to 12.4(mostly-20 to 0),suggesting a mixture of some juvenile arc-derived material and middle Paleoproterozoic heterogeneous crustal sources.The Hf model ages of middle Paleoproterozoic zircons(~1990 Ma)with negativeε_(Hf)(t)values(-12.65 to-6.21,Ave.=-9.8)concentrated around the Meso-Paleoarchean(mean T_(DM)^(C)=3.3–3.1 Ga).For late Neoarchean detrital zircons(~2470 Ma),ε_(Hf)(t)values are divided into two groups,one with negative values(-9.16 to-0.6)with model ages of 3.5–2.9 Ga,the other featuring positive values(1.0 to 3.9)with model ages of 2.9–2.7 Ga,recording a crustal growth event at~2.5 Ga.Neoproterozoic zircons show volcanic arc affinities with partly intraplate magmatic features.We propose that the Banxi Group formed in a rift basin within a passive continental margin setting,which derived detritus from felsic to intermediate rocks from the Yangtze Block and a small amount of arc volcanic rocks.The middle Paleoproterozoic detrital zircon data suggest Columbia-aged basement lies beneath the western Jiangnan orogen.展开更多
The South China Block(SCB)is among the large-scale W-Sn mineralized regions of the globe.The Laojunshan W-Sn-dominant ore area(LOA)in the western part of the SCB preserves the records of the tectonic history of the Te...The South China Block(SCB)is among the large-scale W-Sn mineralized regions of the globe.The Laojunshan W-Sn-dominant ore area(LOA)in the western part of the SCB preserves the records of the tectonic history of the Tethys realm extending through North Vietnam,and Yangtze to Cathaysia blocks,with coeval formation of giant metallic deposits.The prolonged tectonic activities and their control on the genesis and spatio-temporal distribution of giant metallic deposits in the LOA provide a window for a holistic understanding of the tectono-metallogenesis of the SCB.In this study,we present results from a multi-chronologic study to determine the timing of formation of the cassiterite-wolframite-schee lite mineralization.The results suggest three distinct tectono-metallogenic periods in the LOA during the geodynamic evolution of the surrounding tectonic units.The opening of the Proto-Tethys Ocean between the Yangtze-Indochina blocks and the westward Paleo-Pacific subduction beneath the Cathaysia block(420–380 Ma)jointly contributed to the Silurian to early Devonian intracontinental orogeny in the middle of the SCB that involved top-to-the-north thrusting along NE-striking shear zones.This event generated the Dulong-Song Chay granitoids,together with the formation of Xinzhai Sn deposit related to sheared mylonitic granites(ca.419 Ma)and pegmatites(ca.389 Ma),which include the early-stage Sn-sulfide skarn(ca.418 Ma)and the late-stage Sn-bearing schist(ca.389 Ma).During the Late Permian to Late Triassic(260–220 Ma),with the closure of the Proto-Tethys oceans in the west and ongoing Paleo-Pacific westward subduction in the east,the SCB and Indochina Block(IB)were amalgamated which also marks the time of formation of the Nanwenhe scheelite skarn deposit.The subducted PaleoTethys oceanic crust was likely entrained by the nearby rising Emeishan mantle plume(270–259 Ma),which formed the Maguan diabase(ca.260 Ma)that shows significantly older Re-Os model age of ca.268 Ma,suggesting that the Nanwenhe mineralization is potentially derived from ca.260 Ma source.Furthermore,the intraplate shortening induced thin skinned crustal deformation and low grade metamorphism(ca.230 Ma),with the main stage of scheelite-Sn-Mo mineralization(229.9,229.8 and 219 Ma)and contemporary formation of the pegmatite(230.7 Ma).The Late Cretaceous involved two episodes of alternate extension and shortening,driven by the subduction polarity change from northwestward subduction of the Okhotomorsk block to northward subduction of the NeoTethys seafloor.The evolution of the LOA consists of the NW–SE transpression ending ca.100 Ma,the WNW–ESE extension in the earlier episode lasting from 100 Ma to 86 Ma,the WNW–ESE transpression beginning at ca.85 Ma and the NAS extension in the later episode during the latest Cretaceous,which produced the extension-related three periods of Laojunshan granitic magmatism and coeval Sn-W mineralization,with ages in the range of 90–89 Ma,87–85 Ma and 83–79 Ma.We also evaluate the implications of magmaticmetamorphic-metallogenic degassing on the regional paleoclimatic history.展开更多
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)+1 种基金the Basic Research Fund of the Chinese Academy of Geological Sciences(Grant Nos.JKYZD202316,KK2116)the China Scholarship Council project and the Geological Survey project(Grant No.DD20230054).
文摘Rubidium(Rb)deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites.This study investigates a newly-discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Xizang.Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization.LA-ICP-MS U-Pb dating of zircon yielded ages of 19.1±0.2 Ma and 19.0±0.2 Ma for greisenized monzogranite and fresh monzogranite,respectively.The monzogranites are characterized as strongly peraluminous,with high contents of SiO2,Al2O3,K2O and Na2O as well as a high differentiation index.They are enriched in light rare earth and large ion lithophile elements with significant negative Eu anomalies and depleted high fieldstrength elements.Petrological and geochemical features of these ore-related monzogranites suggest that they are highly fractionated S-type granites,derived from remelting of crustal materials in a post-collisional setting.The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore-related monzogranite during the magma’s evolution.The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization.
基金the National Natural Science Foundation of China(Grant Nos.42272075,42250202,41672088,42302073,and 41802093)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(24llgqb001)+1 种基金well as the 2018 Sino-German(CSC-DAAD)Postdoc Scholarship Program,the UCAS Joint PhD Training Program of China[UCAS(2015)37]aFoundation of Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences(KLMR2017-10).
文摘The Huoshaoyun deposit in the Karakorum area of NW China is the world’s largest zinc-lead carbonate ore deposit.Here we investigate the genesis of the mineralization based on multiproxy investigations.The deposit contains zinc-lead carbonate and sulfide minerals,with smithsonite(Smt),cerussite(Cer),and sulfides accounting for 85%,10%,and 5%of the total lead and zinc resources,respectively.Three ore-forming stages,involving Smt,Cer,and sulfides ores were summarized.The Smt mineralization is characterized by veined,massive,and stratified Smt forming horizontal sedimentary layered ore and vertical feeder veins similar to the SEDEX-type deposits.The sulfide and Cer veins display typical hydrothermal characteristics and are superimposed on the massive Smt ores.The Smt ores show high Li,Be,Cr,Y,Ba,Nd,Yb,and Zr contents,whereas the Cer veins have extremely high Sr contents(up to 3814–9174 ppm)and low Zr contents(less than 0.01 ppm).Galena and sphalerite show higher Cd concentrations compared to Smt and Cer ores.The Smt ores differ with different spatial locations,with Smt ores formed at the vent haveδ^(66)Zn values of+0.15‰to+0.21‰,the massive Smt formed close to the vent show a value of+0.13‰,and those formed away from the vent show a value of 0.05‰,all values being close to 0.The sulfides haveδ^(66)Zn values of−0.09‰to+0.04‰.The C-O isotopes of Smt ores are similar to both altered and unaltered host limestone,suggesting that the limestone was a potential source for carbon and oxygen.Quartz with veined Smt shows magmatic signatures withδ^(18)OVSMOW of+1.14‰to+2.23‰,high Pb(115–401 ppm)and Zn concentrations(390–997 ppm),whereas quartz associated with sulfide has meteoric fluid signature with the lowestδ^(18)OVSMOW(−14‰to−10.7‰),low Pb(11.6–49.0 ppm)and Zn(18.1–72.8 ppm)concentrations.The temperature of equilibration computed based on oxygen isotope fractionation between Smt and coeval quartz indicate a dual source with that of quartz derived from an aqueous fluid,whereas the source for Smt might involve CO_(2)or HCO_(3)^(−).We trace multiple metallogenic stages for this deposit including exhalation,hydrothermal deposition,and fault-controlled sulfide vein formation.The largest orebody(III-1)preserves a 16 Mt reserve of Zn and was formed by crust-mantle interaction at ca.195 Ma in the early development of the Linjitang post-arc rift system.Fluid convection,zinc enrichment driven by granitic magma,volcanic activity,and karst alteration induced by acid rain in a lagoonal environment promoted ore enrichment.
基金supported by the National Natural Science Foundation of China[grant number 42272129]Outstanding Youth Science Fund Project of Sichuan Province,China[grant number 23NSFJQ0162]+1 种基金Department of Natural Resources of Sichuan Province,China[grant number KJ-2023-011]the Everest Scientific Research Program of Chengdu University of Technology.
文摘The end-Permian mass extinction was one of the major global crises spanning the entire Early Triassic or longer.Eruptions of volcanos were one of the factors that delayed the biotic recovery after this event.Supervolcano eruptions can cause catastrophic effects on global environment,climate,and life.Here we investigate the tuff layers from Early-Middle Triassic boundary in the Yangtze Block and identify a supervolcano eruption event.The zircon U-Pb ages of the section-Langdai,section-Daijiagou and section-Longmendong tuff samples are 247.1±1.9 Ma,247.6±2.0 Ma and 247.7±1.7 Ma,respectively.These ages mark the Olenekian-Anisian boundary.The zircon grains from the tuff layers have negativeεHf(t)(-15.3 to-0.8),two-stage Hf model(TDM2)ages(1.7 to 2.2 Ga)and display high-δ18O values(mostly>10‰).Clay minerals and quartz dominate the rock composition.The whole rock compositions show that the tuff layers were derived from magma of intermediate to felsic composition,which formed by the remelting of Paleoproterozoic materials of continental crust.The volcanic eruption site is located in the Jinshajiang-Ailaoshan-Song Ma suture zone in the southwestern margin of the Yangtze Block.A combination of the closure of the Paleo-Tethys Ocean Basin and the collision of the Indochina Block and South China contributed to the eruption,which was a supervolcano eruption under the active continental margin arc settings.We speculate that this supervolcano eruption might have contributed to the delayed biotic recovery after the end-Permian mass extinction.
基金financially supported by the Natural Science Foundation of China(Grant No.41972198)the Cooperation Foundation of the Key Laboratory of Mineralogy and Metallogeny,Chinese Academy of Sciences(Grant No.KLMM20180201)the Scientific Research Starting Foundation of Central South University。
文摘The Neoproterozoic evolution of the Jiangnan Orogen is important for understanding the tectonic history of South China.As a volcanic-sedimentary sequence developed in the Nanhua rift,the Banxi Group preserves the records of important magmatic and tectonic events linked to the assembly and breakup of the Rodinia supercontinent.In this study,we report the results from whole-rock major-and trace-element concentrations,with zircon LA-(MC)-ICP-MS U-Pb ages,trace elements and Lu-Hf isotopic compositions of sandstones from the Banxi Group.The rocks are characterized by high SiO_(2)(65.88%–82.76%,with an average of 75.50%)contents,moderate(Fe_(2)O_(3)^(T)+MgO)(1.81%–7.78%,mean:3.79%)and TiO_(2)(0.39%–0.54%,mean:0.48%),low K_(2)O/Na_(2)O(0.03–0.40,mean:0.10)ratios and low Al_2O_(3)/SiO_(2)(0.11–0.24,mean:0.15)ratios.The sandstones have highΣREE contents(mean:179.1 ppm),with chondrite-normalized REE patterns similar to the upper crust and PAAS,showing enriched LREE((La/Yb)_N mean:14.85),sub-horizontal HREE curves and mild Eu(Eu/Eu^(*):0.75–0.89,mean:0.81)negative anomalies.Their geochemical characteristics resemble those of passive continental margin sandstones.Most of the zircons are magmatic in origin and yield a U-Pb age distribution with three peaks:a major age peak at 805 Ma and two subordinate age peaks at 1990 Ma and 2470 Ma,implying three major magmatic sources.The Neoproterozoic zircons haveε_(Hf)(t)values ranging from-47.4 to 12.4(mostly-20 to 0),suggesting a mixture of some juvenile arc-derived material and middle Paleoproterozoic heterogeneous crustal sources.The Hf model ages of middle Paleoproterozoic zircons(~1990 Ma)with negativeε_(Hf)(t)values(-12.65 to-6.21,Ave.=-9.8)concentrated around the Meso-Paleoarchean(mean T_(DM)^(C)=3.3–3.1 Ga).For late Neoarchean detrital zircons(~2470 Ma),ε_(Hf)(t)values are divided into two groups,one with negative values(-9.16 to-0.6)with model ages of 3.5–2.9 Ga,the other featuring positive values(1.0 to 3.9)with model ages of 2.9–2.7 Ga,recording a crustal growth event at~2.5 Ga.Neoproterozoic zircons show volcanic arc affinities with partly intraplate magmatic features.We propose that the Banxi Group formed in a rift basin within a passive continental margin setting,which derived detritus from felsic to intermediate rocks from the Yangtze Block and a small amount of arc volcanic rocks.The middle Paleoproterozoic detrital zircon data suggest Columbia-aged basement lies beneath the western Jiangnan orogen.
基金supported by the China Geological Survey Program(Grant Nos.1212011121260,1212011220928)the National Natural Science Foundation of China(Gant No.91755206)。
文摘The South China Block(SCB)is among the large-scale W-Sn mineralized regions of the globe.The Laojunshan W-Sn-dominant ore area(LOA)in the western part of the SCB preserves the records of the tectonic history of the Tethys realm extending through North Vietnam,and Yangtze to Cathaysia blocks,with coeval formation of giant metallic deposits.The prolonged tectonic activities and their control on the genesis and spatio-temporal distribution of giant metallic deposits in the LOA provide a window for a holistic understanding of the tectono-metallogenesis of the SCB.In this study,we present results from a multi-chronologic study to determine the timing of formation of the cassiterite-wolframite-schee lite mineralization.The results suggest three distinct tectono-metallogenic periods in the LOA during the geodynamic evolution of the surrounding tectonic units.The opening of the Proto-Tethys Ocean between the Yangtze-Indochina blocks and the westward Paleo-Pacific subduction beneath the Cathaysia block(420–380 Ma)jointly contributed to the Silurian to early Devonian intracontinental orogeny in the middle of the SCB that involved top-to-the-north thrusting along NE-striking shear zones.This event generated the Dulong-Song Chay granitoids,together with the formation of Xinzhai Sn deposit related to sheared mylonitic granites(ca.419 Ma)and pegmatites(ca.389 Ma),which include the early-stage Sn-sulfide skarn(ca.418 Ma)and the late-stage Sn-bearing schist(ca.389 Ma).During the Late Permian to Late Triassic(260–220 Ma),with the closure of the Proto-Tethys oceans in the west and ongoing Paleo-Pacific westward subduction in the east,the SCB and Indochina Block(IB)were amalgamated which also marks the time of formation of the Nanwenhe scheelite skarn deposit.The subducted PaleoTethys oceanic crust was likely entrained by the nearby rising Emeishan mantle plume(270–259 Ma),which formed the Maguan diabase(ca.260 Ma)that shows significantly older Re-Os model age of ca.268 Ma,suggesting that the Nanwenhe mineralization is potentially derived from ca.260 Ma source.Furthermore,the intraplate shortening induced thin skinned crustal deformation and low grade metamorphism(ca.230 Ma),with the main stage of scheelite-Sn-Mo mineralization(229.9,229.8 and 219 Ma)and contemporary formation of the pegmatite(230.7 Ma).The Late Cretaceous involved two episodes of alternate extension and shortening,driven by the subduction polarity change from northwestward subduction of the Okhotomorsk block to northward subduction of the NeoTethys seafloor.The evolution of the LOA consists of the NW–SE transpression ending ca.100 Ma,the WNW–ESE extension in the earlier episode lasting from 100 Ma to 86 Ma,the WNW–ESE transpression beginning at ca.85 Ma and the NAS extension in the later episode during the latest Cretaceous,which produced the extension-related three periods of Laojunshan granitic magmatism and coeval Sn-W mineralization,with ages in the range of 90–89 Ma,87–85 Ma and 83–79 Ma.We also evaluate the implications of magmaticmetamorphic-metallogenic degassing on the regional paleoclimatic history.
