Debate has persisted over whether the metamorphic basement of the Zhoushan Islands,easternmost Cathaysia Block,is Precambrian.Here,representative metamorphic rocks from the Qushan Islands were investigated using petro...Debate has persisted over whether the metamorphic basement of the Zhoushan Islands,easternmost Cathaysia Block,is Precambrian.Here,representative metamorphic rocks from the Qushan Islands were investigated using petrography,mineral chemistry,phase equilibria modeling and SHRIMP zircon U-Pb dating to constrain their metamorphic evolution and tectonic significance.Both the pelitic granulites(garnet-kyanite-perthite-biotite-quartz)and the mafic granulites(garnet-clinopyroxene-amphibole-plagioclase-quartz)reached high-pressure granulite-facies conditions of 1.2-1.4 GPa/820-900℃,and recorded three metamorphic stages along a clockwise P-T path with post-peak isothermal decompression.This trajectory indicated rapid exhumation of thickened continental crust during collisional orogeny.Metamorphic ages of 254±3 Ma,262±4 Ma and 259±3 Ma were obtained for mafic granulite,pelitic granulite and marble,respectively,and were consistent with the emplacement age of 259±4 Ma for a pegmatite vein.Detrital zircons in metasediments spanned 2706-330 Ma,which constrained the latest deposition to~330 Ma;thus represented mid-Paleozoic sediment metamorphosed during the late Paleozoic rather than Precambrian basement.We conclude that the Indosinian tectonothermal event in the Cathaysia Block had originated from late Paleozoic-early Mesozoic collisional orogeny between the South China Plate to the north and the Indochina Block to the south.展开更多
1.Objective The Songliao Basin(SB)is situated on the eastern margin of Eurasia continent(Northeast Asia).During the Late Jurassic to Early Cretaceous,hundreds of rifting basins developed in this area,and the SB is a u...1.Objective The Songliao Basin(SB)is situated on the eastern margin of Eurasia continent(Northeast Asia).During the Late Jurassic to Early Cretaceous,hundreds of rifting basins developed in this area,and the SB is a unique case among them as it evolved into the largest rift basin.The rift basin filling of SB includes Huoshiling Formation,Shahezi Formation,and Yingcheng Formation in ascending order.The mega-rifting was controlled by the Mongol-Okhotsk Collisional Belt to the north and northwest and the Pacific Subduction Zone to the east(Wang PJ et al.,2016).As the first rifting succession,the Huoshiling Formation contains key information about the formation of the rifting basins and records the evolution of the Mongol-Okhotsk Collisional Belt and the Pacific Subduction Zone.However,the geological period of the Huoshiling Formation has not been well constrained for two main reasons.First,it is easily confused with the Yingcheng Formation,as both are dominated by volcanogenic-sedimentary successions.Second,there is lack of reliable dating samples from the uppermost part of the Huoshiling Formation due to its considerable burial depth.展开更多
The links between the adakitic rocks and Cu-Au mineralization have long been argued.This study investigates petrogenesis and its link to mineralization potential by a series of in-situ geochronological and geochemical...The links between the adakitic rocks and Cu-Au mineralization have long been argued.This study investigates petrogenesis and its link to mineralization potential by a series of in-situ geochronological and geochemical signatures of apatite and zircon in three ore-related intrusions and one-barren intrusion in the Middle-Lower Yangtze River Metallogenic Belt(MLYRB).Zircon U-Pb dating yield ages of 139–143 Ma and 121 Ma for the ore-related and ore-barren intrusions,respectively.The ore-related rocks have higher apatite Sr/Y(1.57–9.69),(La/Yb)_(N)(16.7–159.5),andδEu(0.45–0.74)than the ore-barren rocks of 0.57–1.02,19.3–24.1 and 0.40–0.45,respectively,indicating the former has an adakitic affinity,while the latter has a non-adakitic affinity.The ore-related rocks have enriched zircon Hf isotopes withε_(Hf)(t)values of-15.9 to-5.5 and T_(DMC)ages of 2408–1655 Ma and apatite Sr-Nd isotopes,indicating that the ore-related magmas were mainly originated from partial melting of subducted oceanic crust.The orebarren rocks have higherε_(Hf)(t)values of-6.6 to-4.6 and lower T_(DMC)ages of 1598–1469 Ma and apatite Sr-Nd isotopes,indicating a lithospheric mantle source.The ore-related rocks have higher oxygen fugacity of mean∆FMQ+2.00 and X_(F)/X_(OH)of 8.36–175 than the ore-barren rocks of mean∆FMQ+1.43 and3.72–4.96.It was inferred that magma source,water content,and oxygen fugacity emerge as critical factors governing the regional Cu-Au mineralization potential.展开更多
The Jiuyishan granitic complex,located in the Nanling Range,South China,is composed of five granitic plutons(Xuehuading,Jinjiling,Pangxiemu,Shaziling and Xishan).Zircon U-Pb dating of four plutons(Jinjiling,Pangxiemu,...The Jiuyishan granitic complex,located in the Nanling Range,South China,is composed of five granitic plutons(Xuehuading,Jinjiling,Pangxiemu,Shaziling and Xishan).Zircon U-Pb dating of four plutons(Jinjiling,Pangxiemu,Shaziling and Xishan)yielded similar ages of approximately 153 Ma,indicating indistinguishable ages within error.Three plutons except the Shaziling pluton,have consistentε_(Nd)(t)(-7.8 to-5.8)andε_(Hf)(t)(-9.1 to-2.2)values,which are similar to those of the lower crustal granulitic metasedimentary and meta-igneous rocks in South China.Compared to other three plutons,the Shaziling pluton has consistentε_(Nd)(t)(-7.4 to-6.8)andε_(Hf)(t)(-7.5 to-4.7)values and shows similar source,but the Shaziling mafic microgranular enclaves(MMEs)show variableε_(Hf)(t)(-14.2 to 4.8)values,indicating a remarkable mantle magma injection of the Shaziling pluton.Zircon Ce/Sm-Yb/Gd,whole-rock CaO-P_(2)O_(5)and CaO-TiO_(2)linear trends reveal that from the Xishan to the Shaziling and from the Jinjiling to the Pangxiemu granites,they experienced apatite and titanite fractionation,respectively.Zircon Th,U,Nb,Ta,Hf,Ti,Y,P and rare earth element(REE)contents and whole-rock Sr,Ba and Rb contents also show that the Shaziling,Xishan,Jinjiling and Pangxiemu granites followed a discontinuous evolutionary series,but the Pangxiemu granites exhibit highly evolved nature.Four main controlling factors of W-Sn and rare metal mineralization in granitic rocks were discussed,and we found that the mineralization in Jiuyishan granitic complex was mainly controlled by the fractionation degree and crystallization temperature,but were rarely affected by oxygen fugacity and mantle material input.The Pangxiemu granites show particularly higher Rb and Ta contents than the other three plutons,implying that the ore deposits developed in the Jiuyishan Complex were directly related to the most evolved Pangxiemu pluton,with the occurrence of Rb and Ta as the most likely rare metal mineralization in the Jiuyishan District.A crystal mush model is proposed to interpret the petrogenetic and mineralizing processes of the Jiuyishan granitic complex.展开更多
Deciphering high-pressure granulite-facies metamorphism and anatexis within a collisional orogeny can provide crucial constraints on geodynamic evolution and melt activity during subduction and exhumation.Combining pe...Deciphering high-pressure granulite-facies metamorphism and anatexis within a collisional orogeny can provide crucial constraints on geodynamic evolution and melt activity during subduction and exhumation.Combining petrographic observations,mineral chemistry,REE in Grt-Cpx thermobarometry,and previous work,at least four stages are suggested for the metamorphic evolution of the mafic granulites in the South Altun,including the protolith stage,the high-pressure granulite-facies stage(909-1037℃and 17.3-30 kbar),medium-pressure granulite-facies overprint(9.1-11.9 kbar and 753-816℃),and subsequent late amphibolite-greenschist-facies metamorphism.Zircon U-Pb dating shows that the mafic granulites underwent high-pressure granulite-facies metamorphism at 497.2±3.7 Ma,while the leucosome formed at 498.2±2.9 Ma.Thus,the leucosomes from the host mafic granulite may have been formed at the high-pressure granulite-facies metamorphic event.The characteristics of zircon morphology,mineral inclusions,low Th/U values,HREE enrichment,and negative Eu anomalies indicate that these zircons from the leucosome were formed from the metamorphic melts.The characteristics of whole-rock major and trace elements as well as Hf isotopic features of zircons between the leucosomes and the host mafic granulite indicate that the melt may have been generated by the partial melting of the host mafic granulite.展开更多
Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addi...Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addition,to avoid the bias of detrital zircon ages caused by variations in zircon fertility,we collected 1709 whole rock zirconium content values(ppm)from granitic rocks with different ages in the North China Craton(NCC).Based on mean Zr content of granitic rocks in each age,these granitic rocks can be divided into four groups:Group A consists of Jurassic,Group B consists of Paleozoic,Neo-Mesoproterozoic and Neoarchean,Group C consists of Early Cretaceous and Triassic,and Group D consists of Paleoproterozoic.This research assigns to these groups zircon fertility factors(ZFF)of 1,1.4,1.8 and 2.2.The U-Pb age of detrital zircons from Late Jurassic sediments corrected by ZFF is statistically analyzed(K-S test,similarity,crosscorrelation,linkeness,and multidimensional scaling).And combining with paleocurrent and paleogeography,we construct two source-to-sink systems:(1)Jiaodong uplift and Sulu Orogenic Belt as the source area and the North Yellow Sea Basin as the sink area;(2)Liaodong Peninsula as the source area and the North Yellow Sea Basin as the sink area.展开更多
The Ordos Basin(OB)in the western part of the North China Craton(NCC),was located at the jointed area of multi-plates and has recorded the Mesozoic tectonic characteristics.Its tectonic evolution in the Mesozoic is si...The Ordos Basin(OB)in the western part of the North China Craton(NCC),was located at the jointed area of multi-plates and has recorded the Mesozoic tectonic characteristics.Its tectonic evolution in the Mesozoic is significant to understand the tectonic transformation of the northern margin of the NCC.In this work,the detrital zircon and apatite(U-Th)/He chronological system were analyzed in the northern part of the OB,and have provided new evidence for the regional tectonic evolution.The(U-Th)/He chronological data states the weighted ages of 240‒235 Ma,141 Ma with the peak distribution of 244 Ma,219 Ma,173 Ma,147‒132 Ma.The thermal evolution,geochronological data,and regional unconformities have proved four stages of regional tectonic evolution for the OB and its surroundings in the Mesozoic:(1)The Late Permian-Early Triassic;(2)the Late Triassic-Early Jurassic;(3)the Late Jurassic-Early Cretaceous;(4)the Late Cretaceous-Early Paleogene.It is indicated that the multi-directional convergence from the surrounding tectonic units has controlled the Mesozoic tectonic evolution of the OB.Four-stage tectonic evolution reflected the activation or end of different plate movements and provided new time constraints for the regional tectonic evolution of the NCC in the Mesozoic.展开更多
When interpreting results,it is imperative to have some understanding of the degree to which the results are replicable.If the results cannot be replicated with independent data,then interpretations from the results b...When interpreting results,it is imperative to have some understanding of the degree to which the results are replicable.If the results cannot be replicated with independent data,then interpretations from the results become questionable.To minimize the potential for misinterpretations,the current study analyzes six time-series derived from globally sampled U-Pb zircon databases–of which,two are independent igneous databases,one being a quasi-independent igneous database,and three being independent detrital databases.These time-series are then analyzed with standard statistical methods to evaluate replicability.The methods include bandpass filtering to transform the raw time-series into stationary sequences,Student’s t-test,Monte Carlo simulations,periodograms from spectral analysis,correlation studies,and correlograms.Each test is designed to determine the replicability of a specific time-series,as well as the replicability of periodicities found from the time-series.The results show at least three key components to assessing replicability:(a)U-Pb igneous and detrital zircon age distributions are highly replicable,(b)time-series replicability gradually deteriorates with age,and(c)replicability is scale dependent,with low frequency cycles being more replicable than high frequency cycles.From the tests,we conclude that four harmonic cycles are highly replicable and statistically significant,these being periodicities of 810,270,90,and 67.5-myr.展开更多
The Tongshan porphyry Cu deposit is well known as one of the most economically significant porphyry deposits in northeast China.Recently,Tongshan has become the largest porphyry Cu deposit in northeast China with the ...The Tongshan porphyry Cu deposit is well known as one of the most economically significant porphyry deposits in northeast China.Recently,Tongshan has become the largest porphyry Cu deposit in northeast China with the successful exploration of the concealed ore zone V.Ore zone V has the largest Cu tonnage(562 Mt@0.50% Cu)and extends into the eastern segment at Tongshan.Compared with ore zones I-III,which are hosted within granitic rocks in the western segment,the ore zone V mainly occurs in Duobaoshan volcanic rocks and the roof pendants of newly discovered intrusions.Here,we conducted a study of the understudied eastern ore zone and found that copper mineralization is associated with the newly discovered suites in the eastern segment at Tongshan.Two periods of ore-bearing quartz veins with different widths have been recognized,including quartz-chalcopyrite-pyrite veinlets(0.1-0.2 cm)and quartz-chalcopyrite-polymetallic sulfide wide veins(>0.5 cm).The latter veins can be divided into four stages(I-IV)of mineralization and alteration,which are closely related to the newly discovered granodiorite and dacite porphyry.Our new zircon U-Pb ages show that the granodiorite and dacite porphyry were developed between 228-223 Ma,suggesting that the overprinting porphyry copper mineralization occurred in the Triassic.The Triassic suites have adakite-like character with high Sr/Y,and show no or minimal negative Eu anomalies,indicating early dominant amphibole with limited plagioclase fractionation.For the Triassic intrusions,the high zircon Eu/Eu*(0.67-0.89),Δ_(FMQ)(1.04±0.53;whereΔ_(FMQ)is the log fO_(2)difference between the sample value and the fayalite-magnetite-quartz mineral buffer),hygrometer values(∼7.19 wt.% H_(2)O)and high whole-rock Fe_(2)O_(3)/FeO,Sr/Y,V/Sc and 10,000×(Eu/Eu*)/Y ratios together indicate the Triassic magmas were oxidized and hydrous.These contents and ratios of the Triassic suites are significantly higher than those of the Ordovician suites(Δ_(FMQ)=0.74±0.26,∼5.90 wt.%H_(2)O),suggesting that the newly discovered Triassic magmas are more oxidized and hydrous,with high potential for porphyry copper mineralization.Based on the investigation of mineralization and the above results,we proposed that multiple superimposed mineralizations can help form a large-scale deposit and the southeastern segment is a favorable exploration area at Tongshan.展开更多
TiAl alloys were melted in BaZrO_(3)crucibles without and with Y addition at 1550℃for 5,10,and 15 min,respectively.The effect of the melting time and Y addition on the interaction between the crucibles and the alloys...TiAl alloys were melted in BaZrO_(3)crucibles without and with Y addition at 1550℃for 5,10,and 15 min,respectively.The effect of the melting time and Y addition on the interaction between the crucibles and the alloys was investigated.Results revealed that the interaction extent was intensified with the increasing melting time.However,it could be effectively suppressed by adding Y into the alloy due to the in situ generated Y_(2)O_(3)protection layer.The thickness of the interaction layer could be decreased from 95.6 to 25.1μm with Y addition at 1550°C for 15 min.In addition,a significant deoxidation effect was achieved by adding Y,and the O concentration of the alloy was decreased from 0.2 to 0.0561 wt.%.In comparison with Al_(2)O_(3),MgO,CaO,and Y_(2)O_(3)crucibles,BaZrO_(3)crucible combined with Y addition exhibited the lowest O contamination to the alloy melt.展开更多
The Shuangjianzishan deposit is a typical magmatic-hydrothermal deposit located in the southern Great Xing'an Range.Recent investigations have identified significant copper and tin mineralization at depth within t...The Shuangjianzishan deposit is a typical magmatic-hydrothermal deposit located in the southern Great Xing'an Range.Recent investigations have identified significant copper and tin mineralization at depth within the Shuangjianzishan deposit;however,the coupling relationship between magmatic emplacement and mineralization processes remains debated.This study presents whole-rock geochemistry,zircon LA-ICP-MS U-Pb dating,and zircon Hf isotope analyses of granite from the northern Shuangjianzishan deposit.The analysis results indicate the granite crystallized between 252.3 and 257.9 Ma,corresponding to Late Permian magmatic activity.The granite displaysε_(Hf)(t)=5.95-14.87,and t_(DM2)=333-900 Ma.Geochemically,the granite is rich in Si and Al,with high K,classified as a calc-alkaline,weakly peraluminous rock.LREEs are enriched,while HREEs are depleted,and a slight negative Eu anomaly,all of which are consistent with A-type granite characteristics.The Hercynian granite in the Shuangjianzishan deposit formed during the latter or post-collisional stages of the collision orogeny following the closure of the Paleo-Asian Ocean in the late Paleozoic era.The material source indicates a mixed origin,involving both crust and mantle contributions.The granite is also enriched in Cu,Pb,and Zn,suggesting its potential role as an ore-forming material source for the Shuangjianzishan deposit.This study proposes a potential link between Hercynian magmatism and mineralization at the Shuangjianzishan deposit for the first time,suggesting that multistage metallogenesis may be a response to successive magmatic events from Hercynian to Yanshanian periods in the mining area.展开更多
Lower Carboniferous clastic sedimentary rocks(i.e.,the Nanduan Formation)in the Changning-Menglian belt of the southeastern Tibetan Plateau may provide new insights into the tectonic evolution of the Paleo-Tethys Ocea...Lower Carboniferous clastic sedimentary rocks(i.e.,the Nanduan Formation)in the Changning-Menglian belt of the southeastern Tibetan Plateau may provide new insights into the tectonic evolution of the Paleo-Tethys Ocean.This paper presents new petrographic,geochemical,and detrital zircon U-Pb age data to constrain the provenance and depositional setting of these rocks.Sandstone samples of the Nanduan Formation are all quartz arenites(Q_(92-99)F_(1-7)L_(0-2))with high SiO_(2)contents(85.1 wt.%-95.2 wt.%;average=90.9 wt.%),indicating high compositional maturity.They exhibit fractionated rare earth element(REE)patterns,with light REE enrichment[(La/Yb)_(N)=6.48-12.1]and negative Eu anomalies(Eu/Eu^(*)=0.53-0.74),and marked negative Sr-Cs-V-Cr-Ni anomalies in upper continental crust-normalised multi-element diagrams.The geochemical features and heavy mineral assemblages suggest that sediments were mainly derived from ancient sedimentary rocks in cratonic interiors or stable continental areas,and were probably deposited in a passive continental margin setting.Detrital zircon U-Pb dating(n=256)of the Nanduan Formation sandstones defines three distinct age peaks in the Pan-African(600-500 Ma),younger Grenvillian(950-850 Ma),and older Grenvillian(1250-1000 Ma).Their zircon age spectra are similar to those of Lower Paleozoic sedimentary rocks(i.e.,the Mengtong and Mengdingjie groups)in the BaoshanSibumasu Block,but significantly different from those of older rocks in the Simao-Indochina and other surrounding blocks(i.e.,the western Yangtze,western Cathaysia,western Qiangtang,Tethyan Himalaya,and Lhasa blocks).This suggests that the Nanduan Formation was deposited at the margin of the Baoshan-Sibumasu Block.Combining the new data presented in this study with published data,we suggest that the Nanduan Formation and underlying Lancang Group were deposited in the same setting during the Early and Late Paleozoic,respectively.展开更多
The Cenozoic source-to-sink history of the Qaidam Basin is crucial for understanding of the basin-filling architecture,mountain-building processes and even the dynamics of the Tibetan Plateau growth.However,the proven...The Cenozoic source-to-sink history of the Qaidam Basin is crucial for understanding of the basin-filling architecture,mountain-building processes and even the dynamics of the Tibetan Plateau growth.However,the provenance history of Cenozoic strata in the Qaidam Basin remains ambiguous,especially in the northern Qaidam Basin.This controversy highlights the importance of obtaining the spatial source-to-sink relationships between the Qaidam Basin and its surrounding mountain ranges.In this study,we investigated the detrital zircon U-Pb ages of modern fluvial systems draining the East Kunlun Mountain.Their detrital zircon age distributions fall into five age groups:300-190,530-360,1000-560,2000-1100 and 2650-2000 Ma.The dominant age groups are 530-360 and 300-190 Ma,which represent the successive subduction of the Proto-Tethys and PaleoTethys Oceans and the subsequent continental collisions,respectively.Combining these new detrital zircon U-Pb ages with available age datasets,we finally obtained complete detrital zircon age information for modern fluvial systems in the whole Qaidam Basin.The U-Pb age distributions of modern river sands reveal that the zircon age signature of basement rocks in the East Kunlun Mountain is significantly different from that in the South Qilian Mountain but is similar to that in the Altyn Tagh Mountain.Moreover,these zircon age observations were confirmed by the significant difference in the Nd isotopic signature of modern river sands,which reveals a significant difference between the East Kunlun Mountain and South Qilian Mountain in the formation and evolution process.展开更多
Detrital zircon geochronology is reported from the c.1200 m thick Cambro-Ordovician sedimentary succession recovered in core from the COSC-2 continental drilling project in the Scandinavian Caledonides.Above a regolit...Detrital zircon geochronology is reported from the c.1200 m thick Cambro-Ordovician sedimentary succession recovered in core from the COSC-2 continental drilling project in the Scandinavian Caledonides.Above a regolith marking the sub-Cambrian peneplain,a lower to middle Cambrian(?)succession comprises conglomerate,sandstone and shale overlain by gravity flows fining upwards into the Alum Shale Formation.First results of detrital zircon geochronology from the Cambrian(?)succession show that the basal section of the autochthonous cover is characterized by mainly late Paleoproterozoic–early Mesoproterozoic detrital grains.The middle part of the succession is dominated by late Paleoproterozoic detritus with minor Mesoproterozoic and Archean input.The upper part of lower Cambrian(?)succession is characterized by Archean to Cambrian detritus.The maximum depositional age is calculated to 530.5±4 Ma for the upper part of the lower Cambrian succession.Two samples from the Lower Ordovician(?)succession above the Alum Shale Formation show predominantly Mesoproterozoic to early Neoproterozoic(1.5–0.9 Ga)ages.The autochthonous lower Cambrian(?)passive margin succession in the lower section is dominated by local detritus,sourced exclusively from the Eastern Segment of the Sveconorwegian Orogen,which includes the basement studied in COSC-2.Up-section,the provenance shifts towards the Transscandinavian Igneous Belt and Svecofennian Orogen sources,with the youngest part of the succession showing a notable input of Neoproterozoic–Cambrian active margin detritus.The Ordovician(?)succession is characterized by populations,likely derived from the Sveconorwegian Orogen,and a minor cratonic contribution.Statistical analysis of detrital zircon datasets across Baltica suggests that the Southern Baltica/Sandomirian Arc,rather than the Timanian Orogen,was a significant source of detrital material across the paleocontinent.The influence of Timanian Orogen grains is limited to northernmost Scandinavia,whereas Sandomirian detritus reached central Scandinavia in the lower to middle Cambrian and remained prevalent in southern Scandinavia into the Lower Ordovician.展开更多
The Southwest Tianshan is the suture zone between the Central Tianshan and the Tarim Craton.To better illustrate the subduction polarity of the Southwest Tianshan Ocean,a systematic detrital zircon LA-ICP-MS U-Pb geoc...The Southwest Tianshan is the suture zone between the Central Tianshan and the Tarim Craton.To better illustrate the subduction polarity of the Southwest Tianshan Ocean,a systematic detrital zircon LA-ICP-MS U-Pb geochronology of sedimentary rocks of the Devonian Apadaerkang Formation and the Carboniferous Akeqiayi Group of the Biedieli area in the Wushi region is the focus.Detrital zircon ages indicate that the youngest grains of the targeted quartz sandstones are Late Devonian and Early Carboniferous in age,respectively.These ages also have relatively similar age spectra,indicating a similar tectonic setting and source in the Biedieli area during the Devonian to Carboniferous.The main spectrum peaks occur at 2360,1960,810,640 and 440 Ma,with a principal age peak in the early Paleozoic(474-430 Ma),and the Central Tianshan Terrane is indicated as the main source.The detrital zircon geochronology and sedimentary characteristics of the Biedieli rocks indicate that the Paleozoic sedimentary rocks in the northern Wushi region were formed at an active continental margin,associated mainly with the early Paleozoic subduction of the South Tianshan Ocean.展开更多
The tectonic evolution of Borneo and the affiliation between Southern and Northern Borneo remains unclear.The Rajang and Crocker Fan sediments,as one of the largest ancient submarine fans in Southeast Asia have witnes...The tectonic evolution of Borneo and the affiliation between Southern and Northern Borneo remains unclear.The Rajang and Crocker Fan sediments,as one of the largest ancient submarine fans in Southeast Asia have witnessed the tectonic evolution of Borneo since at least the late Mesozoic.In this study,we present laser ablation inductively coupled plasma mass spectrometer(LA-ICP-MS)U-Pb dating and Hf isotopic results of detrital zircons from the Trusmadi and Crocker formations within the Crocker Fan of Sabah,Northern Borneo.Our results,coupled with previous data,show that the Crocker Fan sediments in Sabah of Northern Borneo display similar age spectra to the Rajang Fan sediments in Sarawak of Central Borneo,with two major age clusters at 130-80 and 280-200 Ma.Further provenance analysis based on mineral shape with a prismatic characteristic and similar detrital zircon Hf isotopes of the two formations illustrates that the Jurassic-Cretaceous and partly Triassic detrital zircons of the Crocker and Rajang Fan sediments were derived from the erosion of contemporaneous magmatic rocks;part of Permian-Triassic ones could be the recycling of the Jurassic deposits in SW Borneo.The initial provenance of these Permian-Triassic detritus could be synchronous magmatic rocks in the Tin belt of the Malay Peninsula.Combining with previous data,we propose that the entire Borneo continent,including both Southern and Northern Borneo,developed a common Mesozoic continental magmatic arc.Moreover,we postulate that the Rajang and Crocker fans formed in a fore-arc extensional rift basin related to the retreat of the subducted Paleo-Pacific Plate beneath the Northern Borneo margin.展开更多
The Ediacaran Period records a significant turning point in the evolution of life on Earth,witnessing the rise to ecological dominance of macroscopic tissue-grade organisms.The Wenghui biota from the Doushantuo Format...The Ediacaran Period records a significant turning point in the evolution of life on Earth,witnessing the rise to ecological dominance of macroscopic tissue-grade organisms.The Wenghui biota from the Doushantuo Formation of South China hosts abundant multicellular algal macrofossils and problematica,some of which might be closely related to taxa from classic Late Ediacaran assemblages from South Australia and the White Sea biota of Russia.However,a lack of well-resolved isotopic age estimates has hampered efforts to constrain the timing of appearance of the Wenghui biota,obfuscating its significance to our understanding of Ediacaran macroevolution in the aftermath of the Snowball Earth events.Here,we present the first SHRIMP zircon U-Pb dating results for samples obtained from a laminated tuff ash layer at the base of the Wenghui biota in the Doushantuo Formation,Jiangkou County,Tongren City,Guizhou Province,China.Our analyses yield an age of 595.4±5.3 Ma for the first appearance of Wenghui biota,suggesting that its appearance postdated that of the Lantian and Weng'an biotas,but preceded that of the Miaohe biota.These newly obtained age proxies offer an independent test of previous isotopic estimates for the age of the Wenghui biota,providing new chronostratigraphic evidence to map the succession of Ediacaran fossil assemblages on the Yangtze Platform during the Doushantuo interval.These data suggest that the Lantian,Weng'an,Wenghui,and Miaohe biotas may record a sequence of biotic assemblages attesting to successive phases in the radiation of Ediacaran macroscopic organisms,particularly macroalgae.展开更多
Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic ...Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic setting of the northeastern margin of the North China Craton(NCC).Here,we present U-Pb and Lu-Hf analyses of 712 detrital zircons,and U-Pb analyses of 347 detrital apatites from the Baifangzi,Diaoyutai and Qiaotou formations.The Baifangzi and Diaoyutai formations are dominated by Neoarchean(2.5-2.6 Ga)and Paleoproterozoic(1.8-1.9 Ga)zircons,indicating a predominant NCC provenance.The Qiaotou Formation is dominated by Mesoproterozoic(1.5-1.7 Ga and 1.1-1.3 Ga)zircons with mainly positiveεHf(t)values,which are similar to those from eastern Laurentia,implying a significant provenance transition.The detrital apatite age spectra of the Baifangzi and Diaoyutai Formations show major populations at 1.8-1.9 Ga and 1.1-1.3 Ga.Based on their trace element compositions,the Mesoproterozoic apatites were mainly sourced from metamorphic rocks,indicating regional metamorphism occurred in the NCC during 1.1-1.3 Ga.Combining these data with regional studies,we propose that the NCC was adjacent to eastern Laurentia during the assembly of the Rodinia supercontinent.展开更多
To investigate the Early Cretaceous magmatic activity and tectonic evolution in the Xiaoqinggou mining area of Jilin Province,the authors conducted petrological,geochemical,and isotopic analyses of diorite rocks.The f...To investigate the Early Cretaceous magmatic activity and tectonic evolution in the Xiaoqinggou mining area of Jilin Province,the authors conducted petrological,geochemical,and isotopic analyses of diorite rocks.The findings show that the zircons exhibit distinct magmatic growth zoning,confirming their magmatic origin.LA–ICP–MS zircon U–Pb dating yielded an age of 128.7±2.2 Ma,corresponding to Early Cretaceous.Geochemical data reveal that the diorite rocks are high and potassium but low in sodium,classifying them within the peraluminous,high-potassium calc-alkaline series.They are enriched in large ion lithophile elements(e.g.,K,Ba and Rb)and depleted in high field strength elements(e.g.,Nb,Ta and Ti).TheδEu values range from 1.07 to 1.14,indicating weakly positive Eu anomalies.Regional comparisons and integrated studies suggest that the Xiaoqinggou diorite rocks formed in a volcanic island arc setting,associated with the westward subduction of the Paleo-Pacific plate beneath the Eurasian continent in an extensional tectonic environment.This study provides a theoretical basis for further exploration of the Xiaoqinggou deposit.展开更多
Zircon crystals,which form directly from igneous melts,are invaluable for probing the deep crustal basement and provide crucial insights into its composition and evolution.Supercontinent cycles,including the formation...Zircon crystals,which form directly from igneous melts,are invaluable for probing the deep crustal basement and provide crucial insights into its composition and evolution.Supercontinent cycles,including the formation and breakup of Columbia,Rodinia,and Gondwana,play a pivotal role in shaping global magmatic and metamorphic records,and deciphering magmatic patterns is critical for unraveling the complex interplay between tectonics and magmatism.This study investigates U-Pb geochronology and trace/rare earth element(REE)compositions of zircons from the Early Cretaceous Tethyan Himalaya Igneous Province,revealing critical insights into Precambrian-Paleozoic magmatic and tectonic evolution.Dominant Paleoproterozoic(2498 Ma,1912 Ma)and Neoproterozoic(826-762 Ma)zircon populations confirm the existence of the Precambrian basement.Neoproterozoic magmatism shows decoupling between light and heavy REE(LREE/HREE)and europium anomalies(Eu/Eu^(*)=Eu_(N)/(Sm_(N)×Gd_(N))^(1/2))during the 826-762 Ma and 725-702 Ma intervals,indicating that the Rodinia margin evolved from Andean-style subduction to continental collision.Early Paleozoic magmatism correlates with Pan-African orogenesis and subsequent Proto-Tethyan Ocean subduction beneath the Indian Craton.Neo-Tethyan initiation(ca.273 Ma)is evidenced by 200-300 Ma zircons which exhibit(1)absence of LREE/HREE-Eu/Eu^(*)crustal thickness correlations,and(2)a thermal peak at 273 Ma.展开更多
基金supported by the National Natural Science Foundation of China(42072223)Geological Survey project(DD20221649,DD20231429).
文摘Debate has persisted over whether the metamorphic basement of the Zhoushan Islands,easternmost Cathaysia Block,is Precambrian.Here,representative metamorphic rocks from the Qushan Islands were investigated using petrography,mineral chemistry,phase equilibria modeling and SHRIMP zircon U-Pb dating to constrain their metamorphic evolution and tectonic significance.Both the pelitic granulites(garnet-kyanite-perthite-biotite-quartz)and the mafic granulites(garnet-clinopyroxene-amphibole-plagioclase-quartz)reached high-pressure granulite-facies conditions of 1.2-1.4 GPa/820-900℃,and recorded three metamorphic stages along a clockwise P-T path with post-peak isothermal decompression.This trajectory indicated rapid exhumation of thickened continental crust during collisional orogeny.Metamorphic ages of 254±3 Ma,262±4 Ma and 259±3 Ma were obtained for mafic granulite,pelitic granulite and marble,respectively,and were consistent with the emplacement age of 259±4 Ma for a pegmatite vein.Detrital zircons in metasediments spanned 2706-330 Ma,which constrained the latest deposition to~330 Ma;thus represented mid-Paleozoic sediment metamorphosed during the late Paleozoic rather than Precambrian basement.We conclude that the Indosinian tectonothermal event in the Cathaysia Block had originated from late Paleozoic-early Mesozoic collisional orogeny between the South China Plate to the north and the Indochina Block to the south.
基金supported by the National Natural Science Foundation of China(42102135,42072140,42202122 and 41790453)Science and Technology Research Program of Chongqing Municipal Education Commission(KJZD-M202101502,KJQN202201549 and KJQN202101535)+1 种基金Natural Science Foundation of Chongqing(CSTB2022NSCQ-JQX0031 and CSTB2022NSCQMSX1586)China Scholarship Council(202208505055)。
文摘1.Objective The Songliao Basin(SB)is situated on the eastern margin of Eurasia continent(Northeast Asia).During the Late Jurassic to Early Cretaceous,hundreds of rifting basins developed in this area,and the SB is a unique case among them as it evolved into the largest rift basin.The rift basin filling of SB includes Huoshiling Formation,Shahezi Formation,and Yingcheng Formation in ascending order.The mega-rifting was controlled by the Mongol-Okhotsk Collisional Belt to the north and northwest and the Pacific Subduction Zone to the east(Wang PJ et al.,2016).As the first rifting succession,the Huoshiling Formation contains key information about the formation of the rifting basins and records the evolution of the Mongol-Okhotsk Collisional Belt and the Pacific Subduction Zone.However,the geological period of the Huoshiling Formation has not been well constrained for two main reasons.First,it is easily confused with the Yingcheng Formation,as both are dominated by volcanogenic-sedimentary successions.Second,there is lack of reliable dating samples from the uppermost part of the Huoshiling Formation due to its considerable burial depth.
基金supported by the National Natural Science Foundation of China(42472117)the China Geological Survey Project(DD20230040)+1 种基金the Natural Science Foundation of Anhui Province(2108085MD133)the PI Project of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2020GD0802)。
文摘The links between the adakitic rocks and Cu-Au mineralization have long been argued.This study investigates petrogenesis and its link to mineralization potential by a series of in-situ geochronological and geochemical signatures of apatite and zircon in three ore-related intrusions and one-barren intrusion in the Middle-Lower Yangtze River Metallogenic Belt(MLYRB).Zircon U-Pb dating yield ages of 139–143 Ma and 121 Ma for the ore-related and ore-barren intrusions,respectively.The ore-related rocks have higher apatite Sr/Y(1.57–9.69),(La/Yb)_(N)(16.7–159.5),andδEu(0.45–0.74)than the ore-barren rocks of 0.57–1.02,19.3–24.1 and 0.40–0.45,respectively,indicating the former has an adakitic affinity,while the latter has a non-adakitic affinity.The ore-related rocks have enriched zircon Hf isotopes withε_(Hf)(t)values of-15.9 to-5.5 and T_(DMC)ages of 2408–1655 Ma and apatite Sr-Nd isotopes,indicating that the ore-related magmas were mainly originated from partial melting of subducted oceanic crust.The orebarren rocks have higherε_(Hf)(t)values of-6.6 to-4.6 and lower T_(DMC)ages of 1598–1469 Ma and apatite Sr-Nd isotopes,indicating a lithospheric mantle source.The ore-related rocks have higher oxygen fugacity of mean∆FMQ+2.00 and X_(F)/X_(OH)of 8.36–175 than the ore-barren rocks of mean∆FMQ+1.43 and3.72–4.96.It was inferred that magma source,water content,and oxygen fugacity emerge as critical factors governing the regional Cu-Au mineralization potential.
基金financially supported by the Provincial Natural Science Foundation of Hunan(Nos.2019JJ50831,2023JJ30505 and 2023JJ40541)the China Postdoctoral Science Foundation(Nos.2017M622597 and 2021M690591)+2 种基金the Open Research Fund Program of Fundamental Science on Radioactive Geology and Exploration Technology Laboratory(East China University of Technology)(No.2022RGET04)the National Foreign Expert Project(No.G2022029012L)the National Nature Science Foundation of China(No.41002022)。
文摘The Jiuyishan granitic complex,located in the Nanling Range,South China,is composed of five granitic plutons(Xuehuading,Jinjiling,Pangxiemu,Shaziling and Xishan).Zircon U-Pb dating of four plutons(Jinjiling,Pangxiemu,Shaziling and Xishan)yielded similar ages of approximately 153 Ma,indicating indistinguishable ages within error.Three plutons except the Shaziling pluton,have consistentε_(Nd)(t)(-7.8 to-5.8)andε_(Hf)(t)(-9.1 to-2.2)values,which are similar to those of the lower crustal granulitic metasedimentary and meta-igneous rocks in South China.Compared to other three plutons,the Shaziling pluton has consistentε_(Nd)(t)(-7.4 to-6.8)andε_(Hf)(t)(-7.5 to-4.7)values and shows similar source,but the Shaziling mafic microgranular enclaves(MMEs)show variableε_(Hf)(t)(-14.2 to 4.8)values,indicating a remarkable mantle magma injection of the Shaziling pluton.Zircon Ce/Sm-Yb/Gd,whole-rock CaO-P_(2)O_(5)and CaO-TiO_(2)linear trends reveal that from the Xishan to the Shaziling and from the Jinjiling to the Pangxiemu granites,they experienced apatite and titanite fractionation,respectively.Zircon Th,U,Nb,Ta,Hf,Ti,Y,P and rare earth element(REE)contents and whole-rock Sr,Ba and Rb contents also show that the Shaziling,Xishan,Jinjiling and Pangxiemu granites followed a discontinuous evolutionary series,but the Pangxiemu granites exhibit highly evolved nature.Four main controlling factors of W-Sn and rare metal mineralization in granitic rocks were discussed,and we found that the mineralization in Jiuyishan granitic complex was mainly controlled by the fractionation degree and crystallization temperature,but were rarely affected by oxygen fugacity and mantle material input.The Pangxiemu granites show particularly higher Rb and Ta contents than the other three plutons,implying that the ore deposits developed in the Jiuyishan Complex were directly related to the most evolved Pangxiemu pluton,with the occurrence of Rb and Ta as the most likely rare metal mineralization in the Jiuyishan District.A crystal mush model is proposed to interpret the petrogenetic and mineralizing processes of the Jiuyishan granitic complex.
基金financially supported by the Basic Foundation of Tianjin University of Commercethe Fund from the Key Laboratory of Continental Dynamics of Ministry of Natural Resources(J2306)。
文摘Deciphering high-pressure granulite-facies metamorphism and anatexis within a collisional orogeny can provide crucial constraints on geodynamic evolution and melt activity during subduction and exhumation.Combining petrographic observations,mineral chemistry,REE in Grt-Cpx thermobarometry,and previous work,at least four stages are suggested for the metamorphic evolution of the mafic granulites in the South Altun,including the protolith stage,the high-pressure granulite-facies stage(909-1037℃and 17.3-30 kbar),medium-pressure granulite-facies overprint(9.1-11.9 kbar and 753-816℃),and subsequent late amphibolite-greenschist-facies metamorphism.Zircon U-Pb dating shows that the mafic granulites underwent high-pressure granulite-facies metamorphism at 497.2±3.7 Ma,while the leucosome formed at 498.2±2.9 Ma.Thus,the leucosomes from the host mafic granulite may have been formed at the high-pressure granulite-facies metamorphic event.The characteristics of zircon morphology,mineral inclusions,low Th/U values,HREE enrichment,and negative Eu anomalies indicate that these zircons from the leucosome were formed from the metamorphic melts.The characteristics of whole-rock major and trace elements as well as Hf isotopic features of zircons between the leucosomes and the host mafic granulite indicate that the melt may have been generated by the partial melting of the host mafic granulite.
基金supported by the National Natural Science Foundation of China(Nos.41872101 and 41790453-4)。
文摘Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addition,to avoid the bias of detrital zircon ages caused by variations in zircon fertility,we collected 1709 whole rock zirconium content values(ppm)from granitic rocks with different ages in the North China Craton(NCC).Based on mean Zr content of granitic rocks in each age,these granitic rocks can be divided into four groups:Group A consists of Jurassic,Group B consists of Paleozoic,Neo-Mesoproterozoic and Neoarchean,Group C consists of Early Cretaceous and Triassic,and Group D consists of Paleoproterozoic.This research assigns to these groups zircon fertility factors(ZFF)of 1,1.4,1.8 and 2.2.The U-Pb age of detrital zircons from Late Jurassic sediments corrected by ZFF is statistically analyzed(K-S test,similarity,crosscorrelation,linkeness,and multidimensional scaling).And combining with paleocurrent and paleogeography,we construct two source-to-sink systems:(1)Jiaodong uplift and Sulu Orogenic Belt as the source area and the North Yellow Sea Basin as the sink area;(2)Liaodong Peninsula as the source area and the North Yellow Sea Basin as the sink area.
基金This study was jointly supported by the Science&Technology Fundamental Resources Investigation Program(2022FY101800)National Science Foundation(92162212)+1 种基金the project from the Key Laboratory of Tectonics and Petroleum Resources(China University of Geosciences,Wuhan)(TPR-2022-22)the International Geoscience Programme(IGCP-675)。
文摘The Ordos Basin(OB)in the western part of the North China Craton(NCC),was located at the jointed area of multi-plates and has recorded the Mesozoic tectonic characteristics.Its tectonic evolution in the Mesozoic is significant to understand the tectonic transformation of the northern margin of the NCC.In this work,the detrital zircon and apatite(U-Th)/He chronological system were analyzed in the northern part of the OB,and have provided new evidence for the regional tectonic evolution.The(U-Th)/He chronological data states the weighted ages of 240‒235 Ma,141 Ma with the peak distribution of 244 Ma,219 Ma,173 Ma,147‒132 Ma.The thermal evolution,geochronological data,and regional unconformities have proved four stages of regional tectonic evolution for the OB and its surroundings in the Mesozoic:(1)The Late Permian-Early Triassic;(2)the Late Triassic-Early Jurassic;(3)the Late Jurassic-Early Cretaceous;(4)the Late Cretaceous-Early Paleogene.It is indicated that the multi-directional convergence from the surrounding tectonic units has controlled the Mesozoic tectonic evolution of the OB.Four-stage tectonic evolution reflected the activation or end of different plate movements and provided new time constraints for the regional tectonic evolution of the NCC in the Mesozoic.
基金supported by the French Agence Nationale de la Recherche(19-CE31-0002 AstroMeso)the European Research Council under the European Union’s Horizon 2020 Research and Innovation Program(Advanced Grant AstroGeo-885250).
文摘When interpreting results,it is imperative to have some understanding of the degree to which the results are replicable.If the results cannot be replicated with independent data,then interpretations from the results become questionable.To minimize the potential for misinterpretations,the current study analyzes six time-series derived from globally sampled U-Pb zircon databases–of which,two are independent igneous databases,one being a quasi-independent igneous database,and three being independent detrital databases.These time-series are then analyzed with standard statistical methods to evaluate replicability.The methods include bandpass filtering to transform the raw time-series into stationary sequences,Student’s t-test,Monte Carlo simulations,periodograms from spectral analysis,correlation studies,and correlograms.Each test is designed to determine the replicability of a specific time-series,as well as the replicability of periodicities found from the time-series.The results show at least three key components to assessing replicability:(a)U-Pb igneous and detrital zircon age distributions are highly replicable,(b)time-series replicability gradually deteriorates with age,and(c)replicability is scale dependent,with low frequency cycles being more replicable than high frequency cycles.From the tests,we conclude that four harmonic cycles are highly replicable and statistically significant,these being periodicities of 810,270,90,and 67.5-myr.
基金supported by the National Natural Science Foundation of China(41925011)the National Key R&D Program of China(2022YFC2903601).
文摘The Tongshan porphyry Cu deposit is well known as one of the most economically significant porphyry deposits in northeast China.Recently,Tongshan has become the largest porphyry Cu deposit in northeast China with the successful exploration of the concealed ore zone V.Ore zone V has the largest Cu tonnage(562 Mt@0.50% Cu)and extends into the eastern segment at Tongshan.Compared with ore zones I-III,which are hosted within granitic rocks in the western segment,the ore zone V mainly occurs in Duobaoshan volcanic rocks and the roof pendants of newly discovered intrusions.Here,we conducted a study of the understudied eastern ore zone and found that copper mineralization is associated with the newly discovered suites in the eastern segment at Tongshan.Two periods of ore-bearing quartz veins with different widths have been recognized,including quartz-chalcopyrite-pyrite veinlets(0.1-0.2 cm)and quartz-chalcopyrite-polymetallic sulfide wide veins(>0.5 cm).The latter veins can be divided into four stages(I-IV)of mineralization and alteration,which are closely related to the newly discovered granodiorite and dacite porphyry.Our new zircon U-Pb ages show that the granodiorite and dacite porphyry were developed between 228-223 Ma,suggesting that the overprinting porphyry copper mineralization occurred in the Triassic.The Triassic suites have adakite-like character with high Sr/Y,and show no or minimal negative Eu anomalies,indicating early dominant amphibole with limited plagioclase fractionation.For the Triassic intrusions,the high zircon Eu/Eu*(0.67-0.89),Δ_(FMQ)(1.04±0.53;whereΔ_(FMQ)is the log fO_(2)difference between the sample value and the fayalite-magnetite-quartz mineral buffer),hygrometer values(∼7.19 wt.% H_(2)O)and high whole-rock Fe_(2)O_(3)/FeO,Sr/Y,V/Sc and 10,000×(Eu/Eu*)/Y ratios together indicate the Triassic magmas were oxidized and hydrous.These contents and ratios of the Triassic suites are significantly higher than those of the Ordovician suites(Δ_(FMQ)=0.74±0.26,∼5.90 wt.%H_(2)O),suggesting that the newly discovered Triassic magmas are more oxidized and hydrous,with high potential for porphyry copper mineralization.Based on the investigation of mineralization and the above results,we proposed that multiple superimposed mineralizations can help form a large-scale deposit and the southeastern segment is a favorable exploration area at Tongshan.
基金supported by the National Key Research and Development Program(Nos.2022YFB3404501 and 2022YFB3404500)National Natural Science Foundation of China(Nos.52025041,U2341267,52374360,52174294,52450003,52472031,12305374 and 52104305).
文摘TiAl alloys were melted in BaZrO_(3)crucibles without and with Y addition at 1550℃for 5,10,and 15 min,respectively.The effect of the melting time and Y addition on the interaction between the crucibles and the alloys was investigated.Results revealed that the interaction extent was intensified with the increasing melting time.However,it could be effectively suppressed by adding Y into the alloy due to the in situ generated Y_(2)O_(3)protection layer.The thickness of the interaction layer could be decreased from 95.6 to 25.1μm with Y addition at 1550°C for 15 min.In addition,a significant deoxidation effect was achieved by adding Y,and the O concentration of the alloy was decreased from 0.2 to 0.0561 wt.%.In comparison with Al_(2)O_(3),MgO,CaO,and Y_(2)O_(3)crucibles,BaZrO_(3)crucible combined with Y addition exhibited the lowest O contamination to the alloy melt.
基金financed by the Inner Mongolia Geological Exploration Fund Project (Grant No. 2020YS03)the project of “Geology of Mineral Resources in China” from China Geological Survey (Grant Nos. DD20221695, DD20190379, DD20160346)+1 种基金the Project of Transformation in Scientific and Technological Achievements (Grant Nos. 2023CX10, HE2121)the Fundamental Research Funds of the Central Public Welfare Scientific Research Institutes (Grant No. JKYZD202313)
文摘The Shuangjianzishan deposit is a typical magmatic-hydrothermal deposit located in the southern Great Xing'an Range.Recent investigations have identified significant copper and tin mineralization at depth within the Shuangjianzishan deposit;however,the coupling relationship between magmatic emplacement and mineralization processes remains debated.This study presents whole-rock geochemistry,zircon LA-ICP-MS U-Pb dating,and zircon Hf isotope analyses of granite from the northern Shuangjianzishan deposit.The analysis results indicate the granite crystallized between 252.3 and 257.9 Ma,corresponding to Late Permian magmatic activity.The granite displaysε_(Hf)(t)=5.95-14.87,and t_(DM2)=333-900 Ma.Geochemically,the granite is rich in Si and Al,with high K,classified as a calc-alkaline,weakly peraluminous rock.LREEs are enriched,while HREEs are depleted,and a slight negative Eu anomaly,all of which are consistent with A-type granite characteristics.The Hercynian granite in the Shuangjianzishan deposit formed during the latter or post-collisional stages of the collision orogeny following the closure of the Paleo-Asian Ocean in the late Paleozoic era.The material source indicates a mixed origin,involving both crust and mantle contributions.The granite is also enriched in Cu,Pb,and Zn,suggesting its potential role as an ore-forming material source for the Shuangjianzishan deposit.This study proposes a potential link between Hercynian magmatism and mineralization at the Shuangjianzishan deposit for the first time,suggesting that multistage metallogenesis may be a response to successive magmatic events from Hercynian to Yanshanian periods in the mining area.
基金financially supported by the Yunnan Fundamental Research Projects(No.202201AT070077)the Ministry-Province Cooperation Pilot Projects(No.2023ZRBSHZ059)+1 种基金the Major Science and Technology Special Plan of Yunnan Province(No.202202AG050006)the National Natural Science Foundation of China(No.41603032)。
文摘Lower Carboniferous clastic sedimentary rocks(i.e.,the Nanduan Formation)in the Changning-Menglian belt of the southeastern Tibetan Plateau may provide new insights into the tectonic evolution of the Paleo-Tethys Ocean.This paper presents new petrographic,geochemical,and detrital zircon U-Pb age data to constrain the provenance and depositional setting of these rocks.Sandstone samples of the Nanduan Formation are all quartz arenites(Q_(92-99)F_(1-7)L_(0-2))with high SiO_(2)contents(85.1 wt.%-95.2 wt.%;average=90.9 wt.%),indicating high compositional maturity.They exhibit fractionated rare earth element(REE)patterns,with light REE enrichment[(La/Yb)_(N)=6.48-12.1]and negative Eu anomalies(Eu/Eu^(*)=0.53-0.74),and marked negative Sr-Cs-V-Cr-Ni anomalies in upper continental crust-normalised multi-element diagrams.The geochemical features and heavy mineral assemblages suggest that sediments were mainly derived from ancient sedimentary rocks in cratonic interiors or stable continental areas,and were probably deposited in a passive continental margin setting.Detrital zircon U-Pb dating(n=256)of the Nanduan Formation sandstones defines three distinct age peaks in the Pan-African(600-500 Ma),younger Grenvillian(950-850 Ma),and older Grenvillian(1250-1000 Ma).Their zircon age spectra are similar to those of Lower Paleozoic sedimentary rocks(i.e.,the Mengtong and Mengdingjie groups)in the BaoshanSibumasu Block,but significantly different from those of older rocks in the Simao-Indochina and other surrounding blocks(i.e.,the western Yangtze,western Cathaysia,western Qiangtang,Tethyan Himalaya,and Lhasa blocks).This suggests that the Nanduan Formation was deposited at the margin of the Baoshan-Sibumasu Block.Combining the new data presented in this study with published data,we suggest that the Nanduan Formation and underlying Lancang Group were deposited in the same setting during the Early and Late Paleozoic,respectively.
基金supported by the Geological Survey of China(No.DD20221645)the National Natural Science Foundation of China(Nos.42171010,42072141,41702118)。
文摘The Cenozoic source-to-sink history of the Qaidam Basin is crucial for understanding of the basin-filling architecture,mountain-building processes and even the dynamics of the Tibetan Plateau growth.However,the provenance history of Cenozoic strata in the Qaidam Basin remains ambiguous,especially in the northern Qaidam Basin.This controversy highlights the importance of obtaining the spatial source-to-sink relationships between the Qaidam Basin and its surrounding mountain ranges.In this study,we investigated the detrital zircon U-Pb ages of modern fluvial systems draining the East Kunlun Mountain.Their detrital zircon age distributions fall into five age groups:300-190,530-360,1000-560,2000-1100 and 2650-2000 Ma.The dominant age groups are 530-360 and 300-190 Ma,which represent the successive subduction of the Proto-Tethys and PaleoTethys Oceans and the subsequent continental collisions,respectively.Combining these new detrital zircon U-Pb ages with available age datasets,we finally obtained complete detrital zircon age information for modern fluvial systems in the whole Qaidam Basin.The U-Pb age distributions of modern river sands reveal that the zircon age signature of basement rocks in the East Kunlun Mountain is significantly different from that in the South Qilian Mountain but is similar to that in the Altyn Tagh Mountain.Moreover,these zircon age observations were confirmed by the significant difference in the Nd isotopic signature of modern river sands,which reveals a significant difference between the East Kunlun Mountain and South Qilian Mountain in the formation and evolution process.
基金funded by the National Science Centre(NCN,Poland)project nos.2018/29/B/ST10/02315 and 2019/33/B/ST10/01728 and the Swedish Research Council(Vetenskapsrådet)grant no.2019-03688.OL is grateful to the Deutsche Forschunggemeinschaft for the support of his COSC-2 research(DFG 867/12-1,13-1,and 13-2)supported by a National Science Foundation(USA)grant EAR2050246.
文摘Detrital zircon geochronology is reported from the c.1200 m thick Cambro-Ordovician sedimentary succession recovered in core from the COSC-2 continental drilling project in the Scandinavian Caledonides.Above a regolith marking the sub-Cambrian peneplain,a lower to middle Cambrian(?)succession comprises conglomerate,sandstone and shale overlain by gravity flows fining upwards into the Alum Shale Formation.First results of detrital zircon geochronology from the Cambrian(?)succession show that the basal section of the autochthonous cover is characterized by mainly late Paleoproterozoic–early Mesoproterozoic detrital grains.The middle part of the succession is dominated by late Paleoproterozoic detritus with minor Mesoproterozoic and Archean input.The upper part of lower Cambrian(?)succession is characterized by Archean to Cambrian detritus.The maximum depositional age is calculated to 530.5±4 Ma for the upper part of the lower Cambrian succession.Two samples from the Lower Ordovician(?)succession above the Alum Shale Formation show predominantly Mesoproterozoic to early Neoproterozoic(1.5–0.9 Ga)ages.The autochthonous lower Cambrian(?)passive margin succession in the lower section is dominated by local detritus,sourced exclusively from the Eastern Segment of the Sveconorwegian Orogen,which includes the basement studied in COSC-2.Up-section,the provenance shifts towards the Transscandinavian Igneous Belt and Svecofennian Orogen sources,with the youngest part of the succession showing a notable input of Neoproterozoic–Cambrian active margin detritus.The Ordovician(?)succession is characterized by populations,likely derived from the Sveconorwegian Orogen,and a minor cratonic contribution.Statistical analysis of detrital zircon datasets across Baltica suggests that the Southern Baltica/Sandomirian Arc,rather than the Timanian Orogen,was a significant source of detrital material across the paleocontinent.The influence of Timanian Orogen grains is limited to northernmost Scandinavia,whereas Sandomirian detritus reached central Scandinavia in the lower to middle Cambrian and remained prevalent in southern Scandinavia into the Lower Ordovician.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.42172258,42072227,U2244205)the Science and Technology Major Project of Xinjiang Uygur Autonomous Region,China(2023A03002)+2 种基金the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Grant No.2015BAB05B04)the Joint Innovation Fund of China National Uranium Co.,Ltd.,and State Key Laboratory of Nuclear Resources and Environment(Grant No.NRE2021-01)the China Geological Survey(Grant Nos.DD20242868,DZLXJK202206)。
文摘The Southwest Tianshan is the suture zone between the Central Tianshan and the Tarim Craton.To better illustrate the subduction polarity of the Southwest Tianshan Ocean,a systematic detrital zircon LA-ICP-MS U-Pb geochronology of sedimentary rocks of the Devonian Apadaerkang Formation and the Carboniferous Akeqiayi Group of the Biedieli area in the Wushi region is the focus.Detrital zircon ages indicate that the youngest grains of the targeted quartz sandstones are Late Devonian and Early Carboniferous in age,respectively.These ages also have relatively similar age spectra,indicating a similar tectonic setting and source in the Biedieli area during the Devonian to Carboniferous.The main spectrum peaks occur at 2360,1960,810,640 and 440 Ma,with a principal age peak in the early Paleozoic(474-430 Ma),and the Central Tianshan Terrane is indicated as the main source.The detrital zircon geochronology and sedimentary characteristics of the Biedieli rocks indicate that the Paleozoic sedimentary rocks in the northern Wushi region were formed at an active continental margin,associated mainly with the early Paleozoic subduction of the South Tianshan Ocean.
基金jointly supported by the Scientific Research Foundation of Third Institute of Oceanography,Ministry of Natural Resources,Xiamen(No.2018002)the Guangxi Natural Science Fundation(No.2022GXNSFBA035588)+1 种基金the National Natural Science Foundation of China(Nos.41506050,41402193)the Scientific Research Foundation of Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration(No.19-185-17-09)。
文摘The tectonic evolution of Borneo and the affiliation between Southern and Northern Borneo remains unclear.The Rajang and Crocker Fan sediments,as one of the largest ancient submarine fans in Southeast Asia have witnessed the tectonic evolution of Borneo since at least the late Mesozoic.In this study,we present laser ablation inductively coupled plasma mass spectrometer(LA-ICP-MS)U-Pb dating and Hf isotopic results of detrital zircons from the Trusmadi and Crocker formations within the Crocker Fan of Sabah,Northern Borneo.Our results,coupled with previous data,show that the Crocker Fan sediments in Sabah of Northern Borneo display similar age spectra to the Rajang Fan sediments in Sarawak of Central Borneo,with two major age clusters at 130-80 and 280-200 Ma.Further provenance analysis based on mineral shape with a prismatic characteristic and similar detrital zircon Hf isotopes of the two formations illustrates that the Jurassic-Cretaceous and partly Triassic detrital zircons of the Crocker and Rajang Fan sediments were derived from the erosion of contemporaneous magmatic rocks;part of Permian-Triassic ones could be the recycling of the Jurassic deposits in SW Borneo.The initial provenance of these Permian-Triassic detritus could be synchronous magmatic rocks in the Tin belt of the Malay Peninsula.Combining with previous data,we propose that the entire Borneo continent,including both Southern and Northern Borneo,developed a common Mesozoic continental magmatic arc.Moreover,we postulate that the Rajang and Crocker fans formed in a fore-arc extensional rift basin related to the retreat of the subducted Paleo-Pacific Plate beneath the Northern Borneo margin.
基金supported by the National Natural Science Foundation of China(Nos.42172035 and 41572024)the Fundamental Research Funds for the Liaoning Universities(No.LJ202410166012)+1 种基金Geological Survey Project of China(No.DD20221645)Open Foundation(No.203124)of State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,CAS)。
文摘The Ediacaran Period records a significant turning point in the evolution of life on Earth,witnessing the rise to ecological dominance of macroscopic tissue-grade organisms.The Wenghui biota from the Doushantuo Formation of South China hosts abundant multicellular algal macrofossils and problematica,some of which might be closely related to taxa from classic Late Ediacaran assemblages from South Australia and the White Sea biota of Russia.However,a lack of well-resolved isotopic age estimates has hampered efforts to constrain the timing of appearance of the Wenghui biota,obfuscating its significance to our understanding of Ediacaran macroevolution in the aftermath of the Snowball Earth events.Here,we present the first SHRIMP zircon U-Pb dating results for samples obtained from a laminated tuff ash layer at the base of the Wenghui biota in the Doushantuo Formation,Jiangkou County,Tongren City,Guizhou Province,China.Our analyses yield an age of 595.4±5.3 Ma for the first appearance of Wenghui biota,suggesting that its appearance postdated that of the Lantian and Weng'an biotas,but preceded that of the Miaohe biota.These newly obtained age proxies offer an independent test of previous isotopic estimates for the age of the Wenghui biota,providing new chronostratigraphic evidence to map the succession of Ediacaran fossil assemblages on the Yangtze Platform during the Doushantuo interval.These data suggest that the Lantian,Weng'an,Wenghui,and Miaohe biotas may record a sequence of biotic assemblages attesting to successive phases in the radiation of Ediacaran macroscopic organisms,particularly macroalgae.
基金financially supported by the National Natural Science Foundation of China(Grant No.41902224,41602209).
文摘Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic setting of the northeastern margin of the North China Craton(NCC).Here,we present U-Pb and Lu-Hf analyses of 712 detrital zircons,and U-Pb analyses of 347 detrital apatites from the Baifangzi,Diaoyutai and Qiaotou formations.The Baifangzi and Diaoyutai formations are dominated by Neoarchean(2.5-2.6 Ga)and Paleoproterozoic(1.8-1.9 Ga)zircons,indicating a predominant NCC provenance.The Qiaotou Formation is dominated by Mesoproterozoic(1.5-1.7 Ga and 1.1-1.3 Ga)zircons with mainly positiveεHf(t)values,which are similar to those from eastern Laurentia,implying a significant provenance transition.The detrital apatite age spectra of the Baifangzi and Diaoyutai Formations show major populations at 1.8-1.9 Ga and 1.1-1.3 Ga.Based on their trace element compositions,the Mesoproterozoic apatites were mainly sourced from metamorphic rocks,indicating regional metamorphism occurred in the NCC during 1.1-1.3 Ga.Combining these data with regional studies,we propose that the NCC was adjacent to eastern Laurentia during the assembly of the Rodinia supercontinent.
文摘To investigate the Early Cretaceous magmatic activity and tectonic evolution in the Xiaoqinggou mining area of Jilin Province,the authors conducted petrological,geochemical,and isotopic analyses of diorite rocks.The findings show that the zircons exhibit distinct magmatic growth zoning,confirming their magmatic origin.LA–ICP–MS zircon U–Pb dating yielded an age of 128.7±2.2 Ma,corresponding to Early Cretaceous.Geochemical data reveal that the diorite rocks are high and potassium but low in sodium,classifying them within the peraluminous,high-potassium calc-alkaline series.They are enriched in large ion lithophile elements(e.g.,K,Ba and Rb)and depleted in high field strength elements(e.g.,Nb,Ta and Ti).TheδEu values range from 1.07 to 1.14,indicating weakly positive Eu anomalies.Regional comparisons and integrated studies suggest that the Xiaoqinggou diorite rocks formed in a volcanic island arc setting,associated with the westward subduction of the Paleo-Pacific plate beneath the Eurasian continent in an extensional tectonic environment.This study provides a theoretical basis for further exploration of the Xiaoqinggou deposit.
基金funded by the National Natural Science Foundation of China(42172055)。
文摘Zircon crystals,which form directly from igneous melts,are invaluable for probing the deep crustal basement and provide crucial insights into its composition and evolution.Supercontinent cycles,including the formation and breakup of Columbia,Rodinia,and Gondwana,play a pivotal role in shaping global magmatic and metamorphic records,and deciphering magmatic patterns is critical for unraveling the complex interplay between tectonics and magmatism.This study investigates U-Pb geochronology and trace/rare earth element(REE)compositions of zircons from the Early Cretaceous Tethyan Himalaya Igneous Province,revealing critical insights into Precambrian-Paleozoic magmatic and tectonic evolution.Dominant Paleoproterozoic(2498 Ma,1912 Ma)and Neoproterozoic(826-762 Ma)zircon populations confirm the existence of the Precambrian basement.Neoproterozoic magmatism shows decoupling between light and heavy REE(LREE/HREE)and europium anomalies(Eu/Eu^(*)=Eu_(N)/(Sm_(N)×Gd_(N))^(1/2))during the 826-762 Ma and 725-702 Ma intervals,indicating that the Rodinia margin evolved from Andean-style subduction to continental collision.Early Paleozoic magmatism correlates with Pan-African orogenesis and subsequent Proto-Tethyan Ocean subduction beneath the Indian Craton.Neo-Tethyan initiation(ca.273 Ma)is evidenced by 200-300 Ma zircons which exhibit(1)absence of LREE/HREE-Eu/Eu^(*)crustal thickness correlations,and(2)a thermal peak at 273 Ma.
