The petrogenesis and genetic link to polymetallic mineralization of the granites in the Dayishan complex,southern Hunan province remain debated.Here,we present an integrated study on the petrology,zircon U-Pb ages and...The petrogenesis and genetic link to polymetallic mineralization of the granites in the Dayishan complex,southern Hunan province remain debated.Here,we present an integrated study on the petrology,zircon U-Pb ages and whole-rock geochemistry for this complex.Our findings indicate that the southern complex consists of(amphibole-bearing)biotite granites and muscovite granites emplaced at 153-151 Ma,and the central and northern complex consists of two-mica granites and tourmaline-bearing muscovite granites,respectively with the former emplaced at 164 Ma and the latter at 150 Ma.The(amphibole-bearing)biotite granites have SiO_(2) contents of 68.0-73.8 wt% and are enriched in alkalis and rare earth elements and depleted in Sr and Ba.They display Zr+Y+Ce+Nb>350 ppm and 10000×Ga/Al>2.6 along with high zircon saturation temperatures(821-883oC).The two-mica granites and(tourmaline-bearing)muscovite granites have high SiO_(2)(74.4-77.3 wt%)and low Ga/Al,Zr+Nb+Ce+Y,K/Rb,Zr/Hf,and Nb/Ta along with low zircon saturation temperatures(709-817℃).Geochemical characteristics suggest that the(amphibole-bearing)biotite granites are A-type granites generated through shallow dehydration melting of early Paleozoic granitoids,and that the two-mica granites and(tourmaline-bearing)muscovite granites are fractionated A-type granites produced through fractionation crystallization from the(amphibole-bearing)biotite granites accompanied by fluid fractionation.展开更多
Granite origin is crucial to understanding the evolution of continental crust,yet many concerns about granite genesis remain yielding ongoing debates.A new integrated study of petrology,geochronology,mineral chemistry...Granite origin is crucial to understanding the evolution of continental crust,yet many concerns about granite genesis remain yielding ongoing debates.A new integrated study of petrology,geochronology,mineral chemistry and whole-rock geochemistry of the Dupangling granitic complex in South China,indicate that the granites in the western complex were emplaced during the Caledonian(418 Ma);they have SiO_(2)contents of 68.1-70.4 wt%,and are calc-alkaline and strongly peraluminous with high maficity[(TFe_(2)O_(3)+MgO)>4.0 wt%]and exhibit^(87)Sr/^(86)Sr(t)of 0.7234-0.7311 andε_(Nd)(t)of-9.0 to-6.7.The granites in the eastern complex,emplaced during the Indosinian(212 Ma),have high SiO_(2)contents(73.3-79.8 wt%)and exhibit affinities with A-type granites,such as enrichment in alkalis and rare earth elements(REEs),and depletion in Sr and Ba along with high TFeO/(TFeO+MgO),Ga/Al and Zr+Y+Ce+Nb;these granites exhibit^(87)Sr/^(86)Sr(t)of 0.7221 andε_(Nd)(t)of-9.2 to-7.5.Geochemical characteristics suggest that the older Caledonian granites were derived through dehydration melting of Paleoproterozoic metasedimentary rocks plus additional(~20%-32%)input from mafic magma,whereas the Indosinian granites were generated through shallow dehydration melting of the Caledonian granitoids.展开更多
The Suzhou granitic pluton is the first identified Nb-Ta-rich granite in China.To reveal the genetic link between the sequence of magmatic and hydrothermal evolution and Nb-Ta mineralization in different intrusive pha...The Suzhou granitic pluton is the first identified Nb-Ta-rich granite in China.To reveal the genetic link between the sequence of magmatic and hydrothermal evolution and Nb-Ta mineralization in different intrusive phases of the Suzhou granite,whole-rock geochemistry,geochemistry and U-Th-Pb dating of monazite was analyzed.The unique geochemical characteristics show that the Suzhou pluton can be discriminated as an A-type granite.LA-ICP-MS U-Th-Pb dating of monazite in both the medium-and coarse-grained biotite granite(MBG)and the fine-grained biotite granite(FBG)indicates that the granite formed between 124 and 127 Ma.Based on geochemical characteristics and mineral textures,the MBG(Mnz-Ia)and FBG(Mnz-Ib)monazites are classified as magmatic monazites;another monazite(Mnz-II)from the MBG formed during a magmatic-hydrothermal transitional stage.Nb-Ta in the Suzhou pluton gradually concentrated during fractional crystallization and alteration of Ti-rich minerals and biotite.Ultimately,with the involvement of F-Li-rich fluid,Nb-Ta mineralization occurred during the magmatic-hydrothermal transition.The Suzhou pluton is considered part of a 600-km-and NE-SW-trending Nb-rich A-type granite belt together with other Early Cretaceous A-type granites in the Jiangnan Orogen that offers prospects of a new target for Nb-Ta prospecting.展开更多
The Triassic granitoids in Central Tianshan play a key role in determining the petrogenesis and tectonic evolution on the southern margin of the Central Asian orogenic belt.In this study,we present SHRIMP zircon U-Pb ...The Triassic granitoids in Central Tianshan play a key role in determining the petrogenesis and tectonic evolution on the southern margin of the Central Asian orogenic belt.In this study,we present SHRIMP zircon U-Pb ages,Hf isotopic and geochemical data on the Xingxingxia biotite granite,amazonite granite and granitic pegmatite in Central Tianshan,NW China.Zircon U-Pb dating yielded formation ages of 242 Ma for the biotite granite and 240 Ma for the amazonite granite.These granitoid rocks have high K_(2)O with low MgO and CaO contents.They are enriched in Nb,Ta,Hf and Y,while being depleted in Ba and Sr,showing flat HREE patterns and negative Eu anomalies.They have typical A-type granite geochemical signatures with high Ga/A_(1)(8–13)and TFeO/(TFeO+MgO)ratios,showing an A_(2) affinity for biotite granite and an A_(1) affinity for amazonite granite and granitic pegmatite.Zircon ε_(Hf)(t)values of the granitoids are 0.45–2.66,with Hf model ages of 0.99–1.17 Ga.This suggests that these A-type granites originated from partial melting of the lower crust.We propose that Xingxingxia Triassic A-type granites formed under lithospheric extension from post-orogenic to anorogenic intraplate settings and NE-trending regional strike-slip fault-controlled magma emplacement in the upper crust.展开更多
The magma sources,origins and precise forming ages of the miarolite from Qishan and Kuiqi intrusions are still uncertain.New results reveal that,miarolites from the Qishan and Kuiqi intrusions yield crystallization ag...The magma sources,origins and precise forming ages of the miarolite from Qishan and Kuiqi intrusions are still uncertain.New results reveal that,miarolites from the Qishan and Kuiqi intrusions yield crystallization ages of~101 and~98 Ma,and they have a high formation temperature(~910℃)and low oxygen fugacity value,indicating crystallization condition at low pressure in the upper crust with temperature of 678℃.The Qishan and Kuiqi miarolites are characterized by enrichment in SiO_(2) and high-K alkali,depletion in Ca and Mg,and belong to the high-K weak peraluminous rock series.The samples are enriched in HFSEs(i.e.,Ta,Zr and Hf)and LILEs(i.e.,Ba,P and Sr),depleted in Ba and Sr with the negative anomaly of Eu.In the primitive mantle normalized trace element spider diagram,the samples show a right-inclined‘seagull-type’pattern,combined the ratios of(La/Yb)_(N),10000×Al/Ga,Rb/Nb and Nb/Ta etc.,they were proved to be alkaline A-type granite.Combined the characterize of the trace elements,they were derived from clay-rich source accompanied pelite melting,and subjected to K-feldspar crystallization fractional.The values of ε_(Hf)(t)and tDM2 are distributed in the range of-2.8 to 3.3 with~1.2 Ga,and-6.0 to 4.0 with~1.2 Ga,revealing that they were generated from the Mesoproterozoic Cathaysia basement rocks.The comprehensive research reveals the Kuiqi and Qishan intrusions derived from crust-mantle mixing and partial melting of the crust,respectively,resulting from lithospheric extension generated by the Paleo-Pacific Plate subducted into the European-Asian Plate.展开更多
Paleoproterozoic A-type granites are widely distributed in the southern margin of the North China Craton(SNCC),providing important information for understanding the Paleoproterozoic tectonic regimes in this area.This ...Paleoproterozoic A-type granites are widely distributed in the southern margin of the North China Craton(SNCC),providing important information for understanding the Paleoproterozoic tectonic regimes in this area.This paper reports newly obtained whole-rock compositions and zircon U-Pb ages for the Tieluping syenogranite porphyry(TLP)and Huoshenmiao alkali granite porphyry(HSM)in the SNCC.Zircons from the TLP and HSM have U-Pb ages of 1805±12 and 1792±14 Ma,respectively.These ages are taken to date the emplacement of these intrusions.They had high total alkali contents(K_(2)O+Na_(2)O>7.13 wt.%),with high 10000×Ga/Al ratios(3.06–3.41)and Zr+Y+Nb+Ce values(709 ppm–910 ppm)as well as high zircon saturation temperatures(864–970℃),indicative of A-type granite affinities.High Y/Nb(1.75–3.32),Ce/Nb(7.72–9.72),and Yb/Ta(2.89–5.60)ratios suggested that TLP and HSM belonged to the A2-type granite.The negative whole rockε_(Nd)(t)values(−8.4 to−6.6)and negative zirconε_(Hf)(t)values(−15.9 to−6.3)confirmed that TLP and HSM were likely generated by the partial melting of an ancient continental crust.TheεHf(t)(−7.4 to+4.0)values of inherited zircons in the TLP suggested that they were derived from the partial melting of Archean basement rocks.Considering the geochemical similarity of the 1.80 Ga A-type granitoids in the SNCC,we propose that the TLP and HSM were formed in a post-collisional regime that was likely associated with the break-off of the Paleoproterozoic subducted slab.Upwelling of the asthenosphere provided huge heat to generate the regional 1.80 Ga A-type granite in the SNCC.展开更多
[Objective] The research aimed to induce the expression of FMDV structural protein VP1 in E.coli and purify the protein,then detect the activity.[Method] The fragment coding VP1 was amplified by PCR and doubly digeste...[Objective] The research aimed to induce the expression of FMDV structural protein VP1 in E.coli and purify the protein,then detect the activity.[Method] The fragment coding VP1 was amplified by PCR and doubly digested with BamH Ⅰ and XhoⅠ,then cloned into expression vector pGEX-4T-1 and pPROExHTb respectively to get recombinant plasmid pGEX-4T-1-VP1 and pPROExHTb-VP1.The recombinant plasmid pGEX-4T-1-VP1 and pPROExHTb-VP1 was transformed into E.coli BL21(DE3)and induced by IPTG,fusion protein was identifie...展开更多
The Late Cretaceous Jiepailing granitoids,located at the central Nanling Range in South China,are closely associated with significant Sn-Li-Be-F polymetallic metallogeny.The Jiepailing granitoids mainly consist of gra...The Late Cretaceous Jiepailing granitoids,located at the central Nanling Range in South China,are closely associated with significant Sn-Li-Be-F polymetallic metallogeny.The Jiepailing granitoids mainly consist of granitic porphyry and zinnwaldite granite.The two granitoids have an A-type affinity,showing elevated Rb/Sr ratios and significant depletions in Ba,Sr and P.Integrated zircon and monazite U-Pb dating results suggest that granitic porphyry and zinnwaldite granite were emplaced at~89 Ma and~94 Ma,respectively.The low Ce^(4+)/Ce^(3+)ratios of the Jiepailing granitoids,together with significant negative Eu anomalies of the zircons,indicate that their formation occurred under conditions of reduced oxygen fugacity.Through the analysis of zircon Hf-O and whole-rock Nd isotopes,it has been determined that both stages of the Jiepailing granitoids originated in the lower-middle Mesoproterozoic crustal basement[ε_(Nd)(t)=−5.33 to−4.96,t^(C)_(DM)(Nd)=1289-1234 Ma,ε_(Hf)(t)=−4.13 to+2.22,t^(C)_(DM)(Hf)=1418-1015 Ma andδ^(18)O_(Zrc)=6.33‰-7.72‰],with the involvement of mantle-derived materials.Both granitic porphyry and zinnwaldite granite exhibit elevated concentrations of fluorine(F),with the positive correlation between F and Sn emphasizing the crucial role of high F sources in tin mineralization.Drawing upon the study of the Late Cretaceous magma systems in southern Hunan and through comparison with the mineralized granites observed in coastal regions during the Late Cretaceous,a genetic model for the mineralized granites in the Nanling region is developed.When the Paleo-Pacific Plate retreated to the coastal region,the continental crust in southern China underwent extensional thinning and asthenospheric upwelling due to gravitational collapse.Such processes resulted in the partial melting of the middle-lower crustal metamorphic sedimentary basement and the subsequent formation of F-rich granitic magmas,related to tin mineralization.展开更多
Background The Bundelkhand Craton is significant for preserving the multiphase granitoids magmatism from Paleoarchean to Neoarchean periods.It consists of a variety of granite rocks,including TTGs,sanukitoids,and high...Background The Bundelkhand Craton is significant for preserving the multiphase granitoids magmatism from Paleoarchean to Neoarchean periods.It consists of a variety of granite rocks,including TTGs,sanukitoids,and high-K granitoids.This study presents geochemical characteristics of high-silica(68.97 wt.%–73.99 wt.%),low-silica(58.73wt.%–69.94 wt.%),and high K_(2)O(2.77 wt.%–6.16 wt.%)contents of granitoids.Objective The data on Bundelkhand Craton’s granitic magmatism and geodynamics is not sufficiently robust.Geochemical data from this study will be used to further understand the origin,source,and petrogenesis of granitoid rocks and their implications for the evolution of geodynamics.Methodology Twenty-one samples were collected and analyzed for major,trace,and REE elements.Major elements were measured using X-ray fluorescence spectrometry(XRF),and trace and REE elements were analyzed by ICP-MS.Standard procedures from the Geological Survey of India were followed.Results The geochemical analysis presents high-silica(68.97-73.99 wt.%),low-silica(58.73-69.94 wt.%),and high K_(2)O(2.77-6.16 wt.%)contents in granitoids,classified as granite-granodiorite.The rocks are calcic to calcalkalic,magnesian,and range from peraluminous to metaluminous composition.REE patterns showed strong LREE enrichment relative to HREEs,with prominent negative Eu anomalies corresponding to earlier plagioclase fractionation.Multi-element patterns revealed negative anomalies in Nb,Sr,P,and Ti and positive anomalies in Pb.Conclusion The geochemical signatures attributed to the post-collisional magma generation and continental crustal contamination.The studied rocks show A-type and A2-type lineage,suggesting they originated from the melting of continental crust during transitional/post-collisional tectonic activity.The formation of hybrid granitoids in the Bundelkhand Craton is connected to the fractionation of hybrid magmas in shallow-seated magma chambers during these tectonic processes.展开更多
The pervasively distributed granitoids in South China contributed greatly to regional polymetallic mineralization,including tungsten,tin,copper,gold,rare metals,and rare earth elements(REEs).To ascertain the dynamic b...The pervasively distributed granitoids in South China contributed greatly to regional polymetallic mineralization,including tungsten,tin,copper,gold,rare metals,and rare earth elements(REEs).To ascertain the dynamic backgrounds,rock types and genesis of the parent rocks related to the Early-Middle Jurassic ionic rare earth mineralization,typical deposits at Muzishan,Xiahu,and Zudong were investigated by conducting petrographic,geochronologic,whole-rock geochemical,and Sr-Nd-Pb isotope analyses,which found that the parent rocks from the Muzishan deposit were the A1-type K-feldspar granite(~195 Ma),from the Zudong deposit were the A2-type monzogranite(~171 Ma),and from the Xiahu deposit were the I-type monzogranite(~167 Ma).All the three granitic rocks underwent different degrees of fractionation,with the Xiahu granite experiencing the highest degree,followed by the Zudong granite,and the Muzishan granite undergoing the lowest degree.The Muzishan granite was concluded to be formed under an intraplate extensional tectonic regime influenced by the hotspots or the mantle plume.The Zudong granite was formed in a post-arc extensional setting related to subduction-collision-rollback of the paleo-Pacific Plate,which caused upwelling of the asthenosphere,thinning of the lithosphere,and partial melting of crustal materials.The Xiahu granite was generated under a transitional tectonic setting of extension and compression,triggered by delamination and rollback of the paleo-Pacific Plate.展开更多
Alkaline igneous rocks represent one of the most economically important resources of radioactive minerals and rare metals.New field observations and petrographic studies are integrated with whole-rock geochemical anal...Alkaline igneous rocks represent one of the most economically important resources of radioactive minerals and rare metals.New field observations and petrographic studies are integrated with whole-rock geochemical analyses and Gamma ray spectroscopy data of alkaline rocks associated with the Amreit complex.The fieldwork was achieved by the collection of more than forty samples from alkaline granites and alkaline syenites.The youngest rocks cropping out in the study area are the cogenetic alkaline rocks,ranging from alkaline granite to alkaline syenite.These alkaline rocks are composed essentially of K-feldspar,alkali amphiboles(arfvedsonite),and sodic pyroxene,with accessories such as zircon,apatite,and ilmenite.Mineral characterization of the highly radioactive zones in both alkaline granite and alkaline syenite displays enrichment in monazite,thorite,zircon,ferro-columbite,xenotime,and allanite minerals.Geochemical analyses indicate that the Amreit rocks are alkaline with peralkaline affinity and have high concentrations of total alkalis(K_(2)O+Na_(2)O),large ion lithophile elements(LILEs;Ba and Rb),high field strength elements(HFSEs;Y,Zr and Nb),rare earth elements(REEs)and significantly depleted in K,Sr,P,Ti,and Eu,typically of post-collision A-type granites.Typically,the Amreit alkaline igneous rocks are classified as within plate granites and display A2 subtype characteristics.The fractionation of K-feldspars played a distinctive role during the magmatic evolution of these alkaline rocks.The geochemical characteristics indicate that the studied alkaline igneous rocks which were originated by fractional crystallization of alkaline magmas were responsible for the enrichment of the REE and rare metals in the residual melt.The high radioactivity is essentially related to accessory minerals,such as zircon,allanite,and monazite.The alkaline granite is the most U-and Thrich rock,where radioactivity level reaches up to 14.7 ppm(181.55 Bq/kg)e U,40.6 ppm(164.84 Bq/kg)e Th,whereas in alkaline syenite radioactivity level is 8.5 ppm(104.96 Bq/kg)e U,30.2 ppm(122.61 Bq/kg)e Th.These observations suppose that these alkaline rocks may be important targets for REEs and radioactive mineral exploration.展开更多
A-type rocks have drawn considerable attention in the past few decades due to their distinctive mineralogical and geochemical fingerprints and prospective utility for geodynamic reconstruction of the lithosphere.A com...A-type rocks have drawn considerable attention in the past few decades due to their distinctive mineralogical and geochemical fingerprints and prospective utility for geodynamic reconstruction of the lithosphere.A comprehensive study,involving zircon U-Pb geochronology,wholerock elemental and Sr-Nd-Pb isotopic geochemistry,was undertaken to elucidate the origin and evolutionary process for syenites from the Daguiping area in the North Daba mountains,South Qinling belt.The syenites revealed an Ordovician igneous crystallization age of 454.4±17 Ma,coeval with the neighboring mafic rocks.All samples show high SiO_(2),LREEs,and HFSEs(Nb,Ta,Zr and Hf)contents,with negative to slightly positive Eu(Eu/Eu^(*)=0.78-1.08)anomalies.The geochemical characteristics of the Daguiping syenites imply that they are of A_1-type magmatic affinity,which is confirmed by their high total alkali levels(8.57 wt.%-11.94 wt.%),Zr+Nb+Ce+Y contents(738.00 ppm-1734.78 ppm),and 10000×Ga/Al ratios(3.25-4.22),as well as low Y/Nb ratios(0.30-0.40).Our samples exhibit a wide range of initial^(87)Sr/^(86)Sr ratios of 0.701943 to 0.709802 and a narrow range of^(143)Nd/^(144)Nd ratios of 0.512205-0.512246 withε_(Nd)(t)values from+3.0 to+3.8.These rocks display(^(206)Pb/^(204)Pb)_(initial),(^(207)Pb/^(204)Pb)_(initial),and(^(208)Pb/^(204)Pb)_(initial)ratios range from 17.96 to 18.62,15.55 to 15.59,and 36.87 to 38.22,respectively.All of the isotopic data indicate that the syenites were essentially mantle-derived.A cogenetic source for the Daguiping syenites and coeval mafic rocks in the South Qinling belt is supported by their uniform Sr-Nd-Pb isotope data and linear major/trace elemental changes,with prolonged fractional crystallization considered as the essential mechanism for these geochemical discrepancies.Mass-balance and Rayleigh fractionation modeling estimate~85 vol%fractional crystallization involving amphibole,clinopyroxene,plagioclase,Kfeldspar,biotite,Fe-Ti oxide,and quartz,to reproduce the compositional varieties between a coeval mafic rock and the Daguiping syenites.The Daguiping syenites and associated alkaline rocks were likely related to a rifting episode triggered by asthenospheric upwelling,which led to the South Qinling detaching from the South China Block along the Mianlue suture during the Early Paleozoic.展开更多
The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (...The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (SDS) existing in the system.The results show that A-type zeolite can influence methane hydrate formation.At the temperature of 273.5 K and pressure of 8.3 MPa,the distilled water with A-type zeolite can form methane hydrate with gaseous methane in 12 hours.The formation process of the system with A-type zeolite was quite steady and the amount of A-type zeolite can influence the gas storage capacity significantly.The adding of A-type zeolite with 0.067 g·(g water)-1 into 2×10-3 g·g-1 SDS-water solution can increase the gas storage capacity,and the maximum increase rate was 31%.Simultaneously the promotion effect on hydrate formation of 3A-type zeolite is much more obvious than that of 5A-type zeolite when the water adding amounts are 0.033 g·g-1 and 0.067 g·g-1 at the experimental conditions.展开更多
In this study, we present systematic petrological, geochemical, LA-ICP-MS zircon U-Pb ages and Nd isotopic data for the A-type granites and syenites from Suizhou-Zaoyang region. The results show that the peralkaline A...In this study, we present systematic petrological, geochemical, LA-ICP-MS zircon U-Pb ages and Nd isotopic data for the A-type granites and syenites from Suizhou-Zaoyang region. The results show that the peralkaline A-type granites and syenites were episodically emplaced in Suizhou-Zaoyang region between 450±3 and 441±7 Ma which corresponds to Late Ordovician and Early Silurian periods, respectively. Petrologically, the syenite-peralkaline granite association comprises of nephefine normative-syenite and alkaline granite in Guanzishan and quartz normative syenite and alkafine granite in Huangyangshan. The syenite-granite associations are ferroan to alkali in composition. They depict characteristics of typical OIB （oceanic island basalts） derived A-type granites in multi-elements primitive normalized diagram and Ybffa vs. Y/Nb as well as Ce/Nb vs. Y/Nb binary plots. Significant depletion in Ba, Sr, P, Ti and Eu indicates fractionation of feldspars, biotite, amphiboles and Ti-rich augite. The values of eNd（t） in Guanzishan nepheline syenite and alkaline granite are ＋1.81 and ＋2.26, respectively and the calculated two-stage model age for these rocks are 1 040 and 1 003 Ma, respectively. On the other hand, the Huangyangshan alkaline granite has eNd（t） values ranging from ＋2.61 to ＋3.46 and a relatively younger two-stage Nd model age values ranging from 906 to 975 Ma, respectively. Based on these data, we inferred that the Guanzishan nepheline syenites and granites were formed from fractional crystallization of OIB-like basic magmas derived from upweliing of metasomatized lithospheric mantle. The Huangyangshan quartz syenite and granite on the other hand, were formed from similar magmas through fractional crystallization with low input from the ancient crustal rocks. Typically, the rocks exhibit Al-type granite affinity and classified as within plate granites associated with the Ordovician crustal extension and the Silurian rifting.展开更多
About 45%of tungsten,~20%of tin,and~9%of fluorite of known world reserves are associated with Late Mesozoic igneous rocks,Southeast(SE)China.Here we demonstrate that Fogang granite,the largest inland batholith,is main...About 45%of tungsten,~20%of tin,and~9%of fluorite of known world reserves are associated with Late Mesozoic igneous rocks,Southeast(SE)China.Here we demonstrate that Fogang granite,the largest inland batholith,is mainly of A2-type that is commonly found in post-orogenic settings and experienced plate subduction induced metasomatism.In contrast,the Yajishan syenite and Nankunshan granite intruding the Fogang granite~20 Ma later are of A1-type formed in intraplate settings.We found that F-rich fluid fractionation,which could make the decline of Ga/Al ratio,total(Nb+Y+Ce+Zr)and Zr concentrations,Nb/Ta and Zr/Hf ratios,leads to chemical variations of a few Fogang granites changing from A2-type to highly fractionated or I-and S-type granitoids.Crystal and Frich fluid fractionations,as well as crustal contamination most likely derived from the Fogang granite,result in some Nankunshan granites developing from A1-type into A2-type.These late-or post-magmatic processes should be taken into account carefully when discriminating the petrogenetic types of igneous rocks,especially for the A2-type suites.Combining with the distribution of 180-140 Ma A1-and A2-type igneous rocks,rare metal deposits,and fluorite deposits in SE China,we highlight the significant role of slab-released F-rich fluids in formation of A-type suites and subsequent chemical differentiation and rare metal and fluorine mineralization.A model of flat-slab northeastward rollback is thus proposed,in which the subduction front reached somewhere near Fogang and then started to roll back at~165 Ma.The inland Jurassic granites of SE China represent a unique locality for formation of A-type suites and their associated mineralization.These granites are not anorogenic,but they are the result of slab rollback from a flat slab,founding of that slab at shallow levels,and metasomatism of by F-rich fluids related to slab heating by the asthenosphere.展开更多
The petrogenesis and tectonic affinity of Late Mesoproterozoic igneous rocks in the Yangtze Block are important to understand its tectonic evolution within the context of the Rodinia supercontinent’s reconstruction.H...The petrogenesis and tectonic affinity of Late Mesoproterozoic igneous rocks in the Yangtze Block are important to understand its tectonic evolution within the context of the Rodinia supercontinent’s reconstruction.Here,we report the SHRIMP zircon U-Pb ages,geochemistry,and Nd-Hf isotopic data for dacite from the Zegu Formation of the Dengxiangying Group in southwestern Yangtze Block.The crystallization age of the Zegu dacite is 1037 Ma.These rocks have relatively high Ga,Zr,Hf,and HREE contents,as well as high(10000×Ga)/Al(2.7-2.9)and FeOt/MgO(3.8-10.5)ratios,showing a geochemical affinity of A-type granitoids.Moreover,they are characterized by negativeεNd(t)(-3.6 to-7.5)and zirconεHf(t)values(-0.3 to-14.4),indicating that they likely generated via partial melting of an ancient continental crust source.The tectonic discriminant diagrams showed that the Zegu dacites have high Y and Nb contents(plotted in the‘within-plate’magmatic rocks field).In conclusion,the geochemistry and isotopic data indicated that the 1037 Ma felsic volcanic rock in the Dengxiangying Group generated during an intra-plate rift basin along a passive margin.Our work thus argues against a Grenvillian orogen’s existence in the Yangtze Block.In view of the subsequent Neoproterozoic subduction-related magmatism in the region,we suggest that the Yangtze Block might have been along the periphery of the Rodinia.展开更多
Late Paleozoic post-collisional granitoids are widespread in West Junggar, as well as northern Xinjiang. As a representative of those intrusions, the Jietebutiao granite occurs in the southwestern margin of the West J...Late Paleozoic post-collisional granitoids are widespread in West Junggar, as well as northern Xinjiang. As a representative of those intrusions, the Jietebutiao granite occurs in the southwestern margin of the West Junggar （northwest China）, and is mainly composed of mid-coarse- grained monzogranite and syenogranite. In the present study, we report the results of high-precision zircon laser-ablation-inductively-coupled plasma mass-spectrometry U-Pb dating on the Jietebutiao granite for the first time, and yield weighted mean 2~~pb/23SU ages of 287 ＋ 9 Ma and 278 ~ 3 Ma for monzogranite and syenogranite, respectively. The Jietebutiao granite has a pronounced A-type affinity; it is metaluminous to slightly peraluminous; has a high-K calc-alkaline composition; high concentrations of Na20 ＋ I（20, varying from 6.8 to 8.5 wt%; high FeOt/MgO; 10 000Ga/AI ratios, a low CaO, MgO, and TiO2 content; enriched in some large ion lithophile elements （LILE, such as Rb and Th） and high field strength elements （HFSE, such as Zr, Hf, and Y）; and depleted in Sr, Ba, and Ti. In addition, the granite has a relatively high rare earth element （REE） content （except for Eu）, with significant negative Eu anomalies （Eu/Eu＊ = 0.01-0.72）, and showing slight tetrad REE patterns and non-charge and radius controlled （CHARAC） trace element behavior. Petrographic, geochemical, and geochronological data suggest that the parental magma of Jietebutiao intrusions are of mixed origin, and are most probably formed by the interaction between the lower crust- and mantle-derived magmas in the Early Permian post-collisional tectonic setting. The basaltic magmas underplated and interacted with the lower crust that was dominated by deeply buried arc （and back-arc basin） series and the oceanic crust formed in the Paleozoic, and then triggered the partial melting of the juvenile lower crust, producing voluminous granitic melts and forming the Jietebutiao A2-type monzogranites, with the lithospheric mantle progressively thinning and rifting to form Al-type granites, such as syenogranites, in the Jietebutiao pluton. This further proves the important contribution of Late Paleozoic granitic magmatism in terms of vertical crustal growth in northern Xinjiang.展开更多
The Early Cretaceous aluminous A-type granites in the Lower Yangtze River belt(LYRB)can provide important insights into the Mesozoic magmatism in eastern China,but their origin remains highly controversial.In this stu...The Early Cretaceous aluminous A-type granites in the Lower Yangtze River belt(LYRB)can provide important insights into the Mesozoic magmatism in eastern China,but their origin remains highly controversial.In this study,radiogenic Ca-Nd isotopic analysis was performed for syenite porphyry and alkali-feldspar granite porphyry of the Yangshan pluton,a typical aluminous A-type granitic intrusion in the LYRB,to constrain its source and geodynamic setting.The results show thatε_(Ca)(126 Ma),ε_(Nd)(126 Ma)and K/Ca_(source) of the syenite porphyry range from-0.24 to+0.96,-7.2 to-6.0,and 0.31 to 1.26,respectively.The corresponding values for the alkali-feldspar granite porphyry range from 0.26 to 0.84,-8.0 to-6.1,and 0.79 to 1.08,respectively.Binary mixing modeling indicates that they were originated from the same sources with different proportion,namely,a mixing of 50%to 75%Neoproterozoic crust and 50%to 25%asthenospheric mantle.Together with previous works,we propose that the Early Cretaceous subduction of the ridge between the Pacific and Izanagi plates was responsible for the formation of the aluminous A-type granites in the LYRB.展开更多
The Jiuyishan complex massif,located in the northern section of the Nanling region,is a combination of five plutons,namely,the Xuehuading,Jinjiling,Pangxiemu,Shaziling and Xishan plutons.Whole-rock geochemistry,Iminer...The Jiuyishan complex massif,located in the northern section of the Nanling region,is a combination of five plutons,namely,the Xuehuading,Jinjiling,Pangxiemu,Shaziling and Xishan plutons.Whole-rock geochemistry,Imineral electron microprobe analysis,zircon U-Pb dating and Hf isotope analysis were carried out for the Jinjiling and Pangxiemu plutons.The zircon U-Pb dating yields weighted mean ages of 152.9±0.9 Ma for the Jinjiling pluton and 151.7±1.5 Ma for the Pangxiemu pluton,with a narrow gap between them.The Jinjiling and Pangxiemu plutons both have geochemical characteristics of high SiO2,Al2 O3,Na2 O,K2 O and low TiO2,MgO,CaO,P2 O5 contents,with intense depletions in Sr,Ba,Ti,Eu and enrichments in Ga,FeoOT and HFSE,and these characteristics reflect an A-type affinity.From the Jinjiling to the Pangxiemu plutons,the mineral composition of mica changes from lepidomelane to zinnwaldite,with increases in F,Li2 O and Rb2 O contents.The mineral composition of zircon changes from low Zr/Hf to high Zr/Hf,with increasing HfO2,P2 O5 and UO2+ThO2+Y2 O3 contents.The mineral compositions of feldspar indicate that the Pangxiemu pluton contains more alkali feldspar than the Jinjiling pluton.The whole-rock geochemistry and mineral compositions reveal a higher degree of differentiation for the Pangxiemu pluton.The nearly uniformεHf(t)indicates the same source region for the two plutons:both were derived from partial melting of the lower crust,with small contributions of mantle materials.In addition,higher F,lower Nb/Ta and Zr/Hf ratios in the Pangxiemu Pluton suggest a closer relationship with the rare metal mineralization than for the Jinjiling pluton.展开更多
Early Ordovician A-type granites in the northeastern(NE) Songnen Block NE China were studied to better understand the geodynamic settings in this region.This research presents new zircon U–Pb ages and wholerock geoch...Early Ordovician A-type granites in the northeastern(NE) Songnen Block NE China were studied to better understand the geodynamic settings in this region.This research presents new zircon U–Pb ages and wholerock geochemical data for the Early Ordovician granites in the NE Songnen Block. Zircon U–Pb dating indicates that the granite in the Cuibei, Hongxing, and Meixi areas in the NE Songnen Block formed in the Early Ordovician with ages of 471–479 Ma. The granites show geochemical characteristics of high SiO2 and K2 O compositions and low FeOT, MgO, CaO, and P2 O5 compositions. They belong to a high K calc-alkaline series and display a weak peraluminous featurPe with A/CNK values of 0.98–1.14. The rocks have aREE composition of 249.98–423.94 ppm,and are enriched in LREE with(La/Yb)Nvalues of2.87–9.87, and display obvious Eu anomalies(d Eu =0.01–0.29). Trace elements of the studied granites are characterized by enrichment in Rb, Th, U, Pb, Hf, and Sm,and depletion of Ba, Nb, Ta, and Sr. They display geochemical features of high Zr +Y + Nb+Ce values(324–795 ppm) and Ga/Al ratios consistent with A-type granites. Based on particular geochemical features, such as high Rb/Nb(7.98–24.19) and Y/Nb(1.07–3.43), the studied A-type granites can be further classified as an A2-type subgroup. This research indicates that the Early Ordovician A-type granites were formed by the partial melting of ancient crust in an extensional setting. Lower Sr/Y and(Ho/Yb)Nratios indicate that plagioclase and amphibole are residual in the source, and garnet is absent, implying that the magma was generated at low levels of pressure. By contrast, the contemporaneous granites in the SE Xing'an Block suggest a subduction-related tectonic setting, and its adakitic property indicates a thickened continental crust.We suggest that the Paleo-Asian Ocean plate between the Xing'an and Songnen blocks subducted northward during the Early Ordovician. Meanwhile, the NE Songnen Block was exposed to a passive continental margin tectonic setting.展开更多
基金supported financially by the National Natural Science Foundation of China(Grant Nos.41872054 and 41272083)。
文摘The petrogenesis and genetic link to polymetallic mineralization of the granites in the Dayishan complex,southern Hunan province remain debated.Here,we present an integrated study on the petrology,zircon U-Pb ages and whole-rock geochemistry for this complex.Our findings indicate that the southern complex consists of(amphibole-bearing)biotite granites and muscovite granites emplaced at 153-151 Ma,and the central and northern complex consists of two-mica granites and tourmaline-bearing muscovite granites,respectively with the former emplaced at 164 Ma and the latter at 150 Ma.The(amphibole-bearing)biotite granites have SiO_(2) contents of 68.0-73.8 wt% and are enriched in alkalis and rare earth elements and depleted in Sr and Ba.They display Zr+Y+Ce+Nb>350 ppm and 10000×Ga/Al>2.6 along with high zircon saturation temperatures(821-883oC).The two-mica granites and(tourmaline-bearing)muscovite granites have high SiO_(2)(74.4-77.3 wt%)and low Ga/Al,Zr+Nb+Ce+Y,K/Rb,Zr/Hf,and Nb/Ta along with low zircon saturation temperatures(709-817℃).Geochemical characteristics suggest that the(amphibole-bearing)biotite granites are A-type granites generated through shallow dehydration melting of early Paleozoic granitoids,and that the two-mica granites and(tourmaline-bearing)muscovite granites are fractionated A-type granites produced through fractionation crystallization from the(amphibole-bearing)biotite granites accompanied by fluid fractionation.
基金supported financially by the National Natural Science Foundation of China(Grant Nos.41872054 and 41272083)。
文摘Granite origin is crucial to understanding the evolution of continental crust,yet many concerns about granite genesis remain yielding ongoing debates.A new integrated study of petrology,geochronology,mineral chemistry and whole-rock geochemistry of the Dupangling granitic complex in South China,indicate that the granites in the western complex were emplaced during the Caledonian(418 Ma);they have SiO_(2)contents of 68.1-70.4 wt%,and are calc-alkaline and strongly peraluminous with high maficity[(TFe_(2)O_(3)+MgO)>4.0 wt%]and exhibit^(87)Sr/^(86)Sr(t)of 0.7234-0.7311 andε_(Nd)(t)of-9.0 to-6.7.The granites in the eastern complex,emplaced during the Indosinian(212 Ma),have high SiO_(2)contents(73.3-79.8 wt%)and exhibit affinities with A-type granites,such as enrichment in alkalis and rare earth elements(REEs),and depletion in Sr and Ba along with high TFeO/(TFeO+MgO),Ga/Al and Zr+Y+Ce+Nb;these granites exhibit^(87)Sr/^(86)Sr(t)of 0.7221 andε_(Nd)(t)of-9.2 to-7.5.Geochemical characteristics suggest that the older Caledonian granites were derived through dehydration melting of Paleoproterozoic metasedimentary rocks plus additional(~20%-32%)input from mafic magma,whereas the Indosinian granites were generated through shallow dehydration melting of the Caledonian granitoids.
基金supported by the National Natural Science Foundation of China(Grant Nos.41903025 and 41803048)the National Nonprofit Institute Research Grant of IGGE(Grant Nos.AS2024J03,JY202106 and AS2022P03)+2 种基金the Hebei Key Science and Technology Program(Grant No.19057411Z)the National Science and Technology Major Project(Grant No.2024ZD1002402)the China Geological Survey Project(Grant No.DD20221807).
文摘The Suzhou granitic pluton is the first identified Nb-Ta-rich granite in China.To reveal the genetic link between the sequence of magmatic and hydrothermal evolution and Nb-Ta mineralization in different intrusive phases of the Suzhou granite,whole-rock geochemistry,geochemistry and U-Th-Pb dating of monazite was analyzed.The unique geochemical characteristics show that the Suzhou pluton can be discriminated as an A-type granite.LA-ICP-MS U-Th-Pb dating of monazite in both the medium-and coarse-grained biotite granite(MBG)and the fine-grained biotite granite(FBG)indicates that the granite formed between 124 and 127 Ma.Based on geochemical characteristics and mineral textures,the MBG(Mnz-Ia)and FBG(Mnz-Ib)monazites are classified as magmatic monazites;another monazite(Mnz-II)from the MBG formed during a magmatic-hydrothermal transitional stage.Nb-Ta in the Suzhou pluton gradually concentrated during fractional crystallization and alteration of Ti-rich minerals and biotite.Ultimately,with the involvement of F-Li-rich fluid,Nb-Ta mineralization occurred during the magmatic-hydrothermal transition.The Suzhou pluton is considered part of a 600-km-and NE-SW-trending Nb-rich A-type granite belt together with other Early Cretaceous A-type granites in the Jiangnan Orogen that offers prospects of a new target for Nb-Ta prospecting.
文摘The Triassic granitoids in Central Tianshan play a key role in determining the petrogenesis and tectonic evolution on the southern margin of the Central Asian orogenic belt.In this study,we present SHRIMP zircon U-Pb ages,Hf isotopic and geochemical data on the Xingxingxia biotite granite,amazonite granite and granitic pegmatite in Central Tianshan,NW China.Zircon U-Pb dating yielded formation ages of 242 Ma for the biotite granite and 240 Ma for the amazonite granite.These granitoid rocks have high K_(2)O with low MgO and CaO contents.They are enriched in Nb,Ta,Hf and Y,while being depleted in Ba and Sr,showing flat HREE patterns and negative Eu anomalies.They have typical A-type granite geochemical signatures with high Ga/A_(1)(8–13)and TFeO/(TFeO+MgO)ratios,showing an A_(2) affinity for biotite granite and an A_(1) affinity for amazonite granite and granitic pegmatite.Zircon ε_(Hf)(t)values of the granitoids are 0.45–2.66,with Hf model ages of 0.99–1.17 Ga.This suggests that these A-type granites originated from partial melting of the lower crust.We propose that Xingxingxia Triassic A-type granites formed under lithospheric extension from post-orogenic to anorogenic intraplate settings and NE-trending regional strike-slip fault-controlled magma emplacement in the upper crust.
基金granted by Opening Foundation of State Key Laboratory of Continental Dynamics(Grant No.21LCD08),Northwest University。
文摘The magma sources,origins and precise forming ages of the miarolite from Qishan and Kuiqi intrusions are still uncertain.New results reveal that,miarolites from the Qishan and Kuiqi intrusions yield crystallization ages of~101 and~98 Ma,and they have a high formation temperature(~910℃)and low oxygen fugacity value,indicating crystallization condition at low pressure in the upper crust with temperature of 678℃.The Qishan and Kuiqi miarolites are characterized by enrichment in SiO_(2) and high-K alkali,depletion in Ca and Mg,and belong to the high-K weak peraluminous rock series.The samples are enriched in HFSEs(i.e.,Ta,Zr and Hf)and LILEs(i.e.,Ba,P and Sr),depleted in Ba and Sr with the negative anomaly of Eu.In the primitive mantle normalized trace element spider diagram,the samples show a right-inclined‘seagull-type’pattern,combined the ratios of(La/Yb)_(N),10000×Al/Ga,Rb/Nb and Nb/Ta etc.,they were proved to be alkaline A-type granite.Combined the characterize of the trace elements,they were derived from clay-rich source accompanied pelite melting,and subjected to K-feldspar crystallization fractional.The values of ε_(Hf)(t)and tDM2 are distributed in the range of-2.8 to 3.3 with~1.2 Ga,and-6.0 to 4.0 with~1.2 Ga,revealing that they were generated from the Mesoproterozoic Cathaysia basement rocks.The comprehensive research reveals the Kuiqi and Qishan intrusions derived from crust-mantle mixing and partial melting of the crust,respectively,resulting from lithospheric extension generated by the Paleo-Pacific Plate subducted into the European-Asian Plate.
基金supported by the Natural Science Foundation of China(NSFC,Nos.U1603245,41703051,and U1812402)the Chinese Academy of Sciences“Light of West China”Program,and the Natural Science Foundation of Guizhou Province(No.[2018]1171).
文摘Paleoproterozoic A-type granites are widely distributed in the southern margin of the North China Craton(SNCC),providing important information for understanding the Paleoproterozoic tectonic regimes in this area.This paper reports newly obtained whole-rock compositions and zircon U-Pb ages for the Tieluping syenogranite porphyry(TLP)and Huoshenmiao alkali granite porphyry(HSM)in the SNCC.Zircons from the TLP and HSM have U-Pb ages of 1805±12 and 1792±14 Ma,respectively.These ages are taken to date the emplacement of these intrusions.They had high total alkali contents(K_(2)O+Na_(2)O>7.13 wt.%),with high 10000×Ga/Al ratios(3.06–3.41)and Zr+Y+Nb+Ce values(709 ppm–910 ppm)as well as high zircon saturation temperatures(864–970℃),indicative of A-type granite affinities.High Y/Nb(1.75–3.32),Ce/Nb(7.72–9.72),and Yb/Ta(2.89–5.60)ratios suggested that TLP and HSM belonged to the A2-type granite.The negative whole rockε_(Nd)(t)values(−8.4 to−6.6)and negative zirconε_(Hf)(t)values(−15.9 to−6.3)confirmed that TLP and HSM were likely generated by the partial melting of an ancient continental crust.TheεHf(t)(−7.4 to+4.0)values of inherited zircons in the TLP suggested that they were derived from the partial melting of Archean basement rocks.Considering the geochemical similarity of the 1.80 Ga A-type granitoids in the SNCC,we propose that the TLP and HSM were formed in a post-collisional regime that was likely associated with the break-off of the Paleoproterozoic subducted slab.Upwelling of the asthenosphere provided huge heat to generate the regional 1.80 Ga A-type granite in the SNCC.
基金Supported by National Supporting Plan(2006BAD06A14)Transgenic Major Projects(2008ZX08011-004)~~
文摘[Objective] The research aimed to induce the expression of FMDV structural protein VP1 in E.coli and purify the protein,then detect the activity.[Method] The fragment coding VP1 was amplified by PCR and doubly digested with BamH Ⅰ and XhoⅠ,then cloned into expression vector pGEX-4T-1 and pPROExHTb respectively to get recombinant plasmid pGEX-4T-1-VP1 and pPROExHTb-VP1.The recombinant plasmid pGEX-4T-1-VP1 and pPROExHTb-VP1 was transformed into E.coli BL21(DE3)and induced by IPTG,fusion protein was identifie...
基金financially supported by the National Natural Science Foundation of China(Grant No.42303073).
文摘The Late Cretaceous Jiepailing granitoids,located at the central Nanling Range in South China,are closely associated with significant Sn-Li-Be-F polymetallic metallogeny.The Jiepailing granitoids mainly consist of granitic porphyry and zinnwaldite granite.The two granitoids have an A-type affinity,showing elevated Rb/Sr ratios and significant depletions in Ba,Sr and P.Integrated zircon and monazite U-Pb dating results suggest that granitic porphyry and zinnwaldite granite were emplaced at~89 Ma and~94 Ma,respectively.The low Ce^(4+)/Ce^(3+)ratios of the Jiepailing granitoids,together with significant negative Eu anomalies of the zircons,indicate that their formation occurred under conditions of reduced oxygen fugacity.Through the analysis of zircon Hf-O and whole-rock Nd isotopes,it has been determined that both stages of the Jiepailing granitoids originated in the lower-middle Mesoproterozoic crustal basement[ε_(Nd)(t)=−5.33 to−4.96,t^(C)_(DM)(Nd)=1289-1234 Ma,ε_(Hf)(t)=−4.13 to+2.22,t^(C)_(DM)(Hf)=1418-1015 Ma andδ^(18)O_(Zrc)=6.33‰-7.72‰],with the involvement of mantle-derived materials.Both granitic porphyry and zinnwaldite granite exhibit elevated concentrations of fluorine(F),with the positive correlation between F and Sn emphasizing the crucial role of high F sources in tin mineralization.Drawing upon the study of the Late Cretaceous magma systems in southern Hunan and through comparison with the mineralized granites observed in coastal regions during the Late Cretaceous,a genetic model for the mineralized granites in the Nanling region is developed.When the Paleo-Pacific Plate retreated to the coastal region,the continental crust in southern China underwent extensional thinning and asthenospheric upwelling due to gravitational collapse.Such processes resulted in the partial melting of the middle-lower crustal metamorphic sedimentary basement and the subsequent formation of F-rich granitic magmas,related to tin mineralization.
基金Geological Survey of India,Northern Region have provided the financial funding for the study.
文摘Background The Bundelkhand Craton is significant for preserving the multiphase granitoids magmatism from Paleoarchean to Neoarchean periods.It consists of a variety of granite rocks,including TTGs,sanukitoids,and high-K granitoids.This study presents geochemical characteristics of high-silica(68.97 wt.%–73.99 wt.%),low-silica(58.73wt.%–69.94 wt.%),and high K_(2)O(2.77 wt.%–6.16 wt.%)contents of granitoids.Objective The data on Bundelkhand Craton’s granitic magmatism and geodynamics is not sufficiently robust.Geochemical data from this study will be used to further understand the origin,source,and petrogenesis of granitoid rocks and their implications for the evolution of geodynamics.Methodology Twenty-one samples were collected and analyzed for major,trace,and REE elements.Major elements were measured using X-ray fluorescence spectrometry(XRF),and trace and REE elements were analyzed by ICP-MS.Standard procedures from the Geological Survey of India were followed.Results The geochemical analysis presents high-silica(68.97-73.99 wt.%),low-silica(58.73-69.94 wt.%),and high K_(2)O(2.77-6.16 wt.%)contents in granitoids,classified as granite-granodiorite.The rocks are calcic to calcalkalic,magnesian,and range from peraluminous to metaluminous composition.REE patterns showed strong LREE enrichment relative to HREEs,with prominent negative Eu anomalies corresponding to earlier plagioclase fractionation.Multi-element patterns revealed negative anomalies in Nb,Sr,P,and Ti and positive anomalies in Pb.Conclusion The geochemical signatures attributed to the post-collisional magma generation and continental crustal contamination.The studied rocks show A-type and A2-type lineage,suggesting they originated from the melting of continental crust during transitional/post-collisional tectonic activity.The formation of hybrid granitoids in the Bundelkhand Craton is connected to the fractionation of hybrid magmas in shallow-seated magma chambers during these tectonic processes.
基金supported by the Open Fund Project of the Key Laboratory of Ionic Rare Earth Resources and Environment,Ministry of Natural Resources(Grant No.2022IREE101)the Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001)the Geological Investigation Project(Grant Nos.DD20243483,DD20221643).
文摘The pervasively distributed granitoids in South China contributed greatly to regional polymetallic mineralization,including tungsten,tin,copper,gold,rare metals,and rare earth elements(REEs).To ascertain the dynamic backgrounds,rock types and genesis of the parent rocks related to the Early-Middle Jurassic ionic rare earth mineralization,typical deposits at Muzishan,Xiahu,and Zudong were investigated by conducting petrographic,geochronologic,whole-rock geochemical,and Sr-Nd-Pb isotope analyses,which found that the parent rocks from the Muzishan deposit were the A1-type K-feldspar granite(~195 Ma),from the Zudong deposit were the A2-type monzogranite(~171 Ma),and from the Xiahu deposit were the I-type monzogranite(~167 Ma).All the three granitic rocks underwent different degrees of fractionation,with the Xiahu granite experiencing the highest degree,followed by the Zudong granite,and the Muzishan granite undergoing the lowest degree.The Muzishan granite was concluded to be formed under an intraplate extensional tectonic regime influenced by the hotspots or the mantle plume.The Zudong granite was formed in a post-arc extensional setting related to subduction-collision-rollback of the paleo-Pacific Plate,which caused upwelling of the asthenosphere,thinning of the lithosphere,and partial melting of crustal materials.The Xiahu granite was generated under a transitional tectonic setting of extension and compression,triggered by delamination and rollback of the paleo-Pacific Plate.
文摘Alkaline igneous rocks represent one of the most economically important resources of radioactive minerals and rare metals.New field observations and petrographic studies are integrated with whole-rock geochemical analyses and Gamma ray spectroscopy data of alkaline rocks associated with the Amreit complex.The fieldwork was achieved by the collection of more than forty samples from alkaline granites and alkaline syenites.The youngest rocks cropping out in the study area are the cogenetic alkaline rocks,ranging from alkaline granite to alkaline syenite.These alkaline rocks are composed essentially of K-feldspar,alkali amphiboles(arfvedsonite),and sodic pyroxene,with accessories such as zircon,apatite,and ilmenite.Mineral characterization of the highly radioactive zones in both alkaline granite and alkaline syenite displays enrichment in monazite,thorite,zircon,ferro-columbite,xenotime,and allanite minerals.Geochemical analyses indicate that the Amreit rocks are alkaline with peralkaline affinity and have high concentrations of total alkalis(K_(2)O+Na_(2)O),large ion lithophile elements(LILEs;Ba and Rb),high field strength elements(HFSEs;Y,Zr and Nb),rare earth elements(REEs)and significantly depleted in K,Sr,P,Ti,and Eu,typically of post-collision A-type granites.Typically,the Amreit alkaline igneous rocks are classified as within plate granites and display A2 subtype characteristics.The fractionation of K-feldspars played a distinctive role during the magmatic evolution of these alkaline rocks.The geochemical characteristics indicate that the studied alkaline igneous rocks which were originated by fractional crystallization of alkaline magmas were responsible for the enrichment of the REE and rare metals in the residual melt.The high radioactivity is essentially related to accessory minerals,such as zircon,allanite,and monazite.The alkaline granite is the most U-and Thrich rock,where radioactivity level reaches up to 14.7 ppm(181.55 Bq/kg)e U,40.6 ppm(164.84 Bq/kg)e Th,whereas in alkaline syenite radioactivity level is 8.5 ppm(104.96 Bq/kg)e U,30.2 ppm(122.61 Bq/kg)e Th.These observations suppose that these alkaline rocks may be important targets for REEs and radioactive mineral exploration.
基金jointly supported by the Natural Science Foundation of China(Nos.42172056,41772052)。
文摘A-type rocks have drawn considerable attention in the past few decades due to their distinctive mineralogical and geochemical fingerprints and prospective utility for geodynamic reconstruction of the lithosphere.A comprehensive study,involving zircon U-Pb geochronology,wholerock elemental and Sr-Nd-Pb isotopic geochemistry,was undertaken to elucidate the origin and evolutionary process for syenites from the Daguiping area in the North Daba mountains,South Qinling belt.The syenites revealed an Ordovician igneous crystallization age of 454.4±17 Ma,coeval with the neighboring mafic rocks.All samples show high SiO_(2),LREEs,and HFSEs(Nb,Ta,Zr and Hf)contents,with negative to slightly positive Eu(Eu/Eu^(*)=0.78-1.08)anomalies.The geochemical characteristics of the Daguiping syenites imply that they are of A_1-type magmatic affinity,which is confirmed by their high total alkali levels(8.57 wt.%-11.94 wt.%),Zr+Nb+Ce+Y contents(738.00 ppm-1734.78 ppm),and 10000×Ga/Al ratios(3.25-4.22),as well as low Y/Nb ratios(0.30-0.40).Our samples exhibit a wide range of initial^(87)Sr/^(86)Sr ratios of 0.701943 to 0.709802 and a narrow range of^(143)Nd/^(144)Nd ratios of 0.512205-0.512246 withε_(Nd)(t)values from+3.0 to+3.8.These rocks display(^(206)Pb/^(204)Pb)_(initial),(^(207)Pb/^(204)Pb)_(initial),and(^(208)Pb/^(204)Pb)_(initial)ratios range from 17.96 to 18.62,15.55 to 15.59,and 36.87 to 38.22,respectively.All of the isotopic data indicate that the syenites were essentially mantle-derived.A cogenetic source for the Daguiping syenites and coeval mafic rocks in the South Qinling belt is supported by their uniform Sr-Nd-Pb isotope data and linear major/trace elemental changes,with prolonged fractional crystallization considered as the essential mechanism for these geochemical discrepancies.Mass-balance and Rayleigh fractionation modeling estimate~85 vol%fractional crystallization involving amphibole,clinopyroxene,plagioclase,Kfeldspar,biotite,Fe-Ti oxide,and quartz,to reproduce the compositional varieties between a coeval mafic rock and the Daguiping syenites.The Daguiping syenites and associated alkaline rocks were likely related to a rifting episode triggered by asthenospheric upwelling,which led to the South Qinling detaching from the South China Block along the Mianlue suture during the Early Paleozoic.
基金Supported by the National Natural Science Foundation of China （50876107）, the National Basic Research Program of China （2009CB219504）, NSFC-Guangdong Union Foundation （NSFC-U0733033） and CAS Program （KGCX2-YW-805）.
文摘The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (SDS) existing in the system.The results show that A-type zeolite can influence methane hydrate formation.At the temperature of 273.5 K and pressure of 8.3 MPa,the distilled water with A-type zeolite can form methane hydrate with gaseous methane in 12 hours.The formation process of the system with A-type zeolite was quite steady and the amount of A-type zeolite can influence the gas storage capacity significantly.The adding of A-type zeolite with 0.067 g·(g water)-1 into 2×10-3 g·g-1 SDS-water solution can increase the gas storage capacity,and the maximum increase rate was 31%.Simultaneously the promotion effect on hydrate formation of 3A-type zeolite is much more obvious than that of 5A-type zeolite when the water adding amounts are 0.033 g·g-1 and 0.067 g·g-1 at the experimental conditions.
基金the support from the National Natural Science Foundation of China(No.41502046)partial financial support by the China Geological Survey(No.DD20160030the Fundamental Research Funds for the Central Universities,China University of Geosciences,Wuhan(No.CUGCJ1711)
文摘In this study, we present systematic petrological, geochemical, LA-ICP-MS zircon U-Pb ages and Nd isotopic data for the A-type granites and syenites from Suizhou-Zaoyang region. The results show that the peralkaline A-type granites and syenites were episodically emplaced in Suizhou-Zaoyang region between 450±3 and 441±7 Ma which corresponds to Late Ordovician and Early Silurian periods, respectively. Petrologically, the syenite-peralkaline granite association comprises of nephefine normative-syenite and alkaline granite in Guanzishan and quartz normative syenite and alkafine granite in Huangyangshan. The syenite-granite associations are ferroan to alkali in composition. They depict characteristics of typical OIB （oceanic island basalts） derived A-type granites in multi-elements primitive normalized diagram and Ybffa vs. Y/Nb as well as Ce/Nb vs. Y/Nb binary plots. Significant depletion in Ba, Sr, P, Ti and Eu indicates fractionation of feldspars, biotite, amphiboles and Ti-rich augite. The values of eNd（t） in Guanzishan nepheline syenite and alkaline granite are ＋1.81 and ＋2.26, respectively and the calculated two-stage model age for these rocks are 1 040 and 1 003 Ma, respectively. On the other hand, the Huangyangshan alkaline granite has eNd（t） values ranging from ＋2.61 to ＋3.46 and a relatively younger two-stage Nd model age values ranging from 906 to 975 Ma, respectively. Based on these data, we inferred that the Guanzishan nepheline syenites and granites were formed from fractional crystallization of OIB-like basic magmas derived from upweliing of metasomatized lithospheric mantle. The Huangyangshan quartz syenite and granite on the other hand, were formed from similar magmas through fractional crystallization with low input from the ancient crustal rocks. Typically, the rocks exhibit Al-type granite affinity and classified as within plate granites associated with the Ordovician crustal extension and the Silurian rifting.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2019B030302013)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB42000000)+1 种基金the National Natural Science Foundation of China(No.41773054)the National Key R&D Program of China(No.2016YFC0600408)。
文摘About 45%of tungsten,~20%of tin,and~9%of fluorite of known world reserves are associated with Late Mesozoic igneous rocks,Southeast(SE)China.Here we demonstrate that Fogang granite,the largest inland batholith,is mainly of A2-type that is commonly found in post-orogenic settings and experienced plate subduction induced metasomatism.In contrast,the Yajishan syenite and Nankunshan granite intruding the Fogang granite~20 Ma later are of A1-type formed in intraplate settings.We found that F-rich fluid fractionation,which could make the decline of Ga/Al ratio,total(Nb+Y+Ce+Zr)and Zr concentrations,Nb/Ta and Zr/Hf ratios,leads to chemical variations of a few Fogang granites changing from A2-type to highly fractionated or I-and S-type granitoids.Crystal and Frich fluid fractionations,as well as crustal contamination most likely derived from the Fogang granite,result in some Nankunshan granites developing from A1-type into A2-type.These late-or post-magmatic processes should be taken into account carefully when discriminating the petrogenetic types of igneous rocks,especially for the A2-type suites.Combining with the distribution of 180-140 Ma A1-and A2-type igneous rocks,rare metal deposits,and fluorite deposits in SE China,we highlight the significant role of slab-released F-rich fluids in formation of A-type suites and subsequent chemical differentiation and rare metal and fluorine mineralization.A model of flat-slab northeastward rollback is thus proposed,in which the subduction front reached somewhere near Fogang and then started to roll back at~165 Ma.The inland Jurassic granites of SE China represent a unique locality for formation of A-type suites and their associated mineralization.These granites are not anorogenic,but they are the result of slab rollback from a flat slab,founding of that slab at shallow levels,and metasomatism of by F-rich fluids related to slab heating by the asthenosphere.
基金financially supported by the China Geological Survey(Nos.DD20190370,121201111120117)。
文摘The petrogenesis and tectonic affinity of Late Mesoproterozoic igneous rocks in the Yangtze Block are important to understand its tectonic evolution within the context of the Rodinia supercontinent’s reconstruction.Here,we report the SHRIMP zircon U-Pb ages,geochemistry,and Nd-Hf isotopic data for dacite from the Zegu Formation of the Dengxiangying Group in southwestern Yangtze Block.The crystallization age of the Zegu dacite is 1037 Ma.These rocks have relatively high Ga,Zr,Hf,and HREE contents,as well as high(10000×Ga)/Al(2.7-2.9)and FeOt/MgO(3.8-10.5)ratios,showing a geochemical affinity of A-type granitoids.Moreover,they are characterized by negativeεNd(t)(-3.6 to-7.5)and zirconεHf(t)values(-0.3 to-14.4),indicating that they likely generated via partial melting of an ancient continental crust source.The tectonic discriminant diagrams showed that the Zegu dacites have high Y and Nb contents(plotted in the‘within-plate’magmatic rocks field).In conclusion,the geochemistry and isotopic data indicated that the 1037 Ma felsic volcanic rock in the Dengxiangying Group generated during an intra-plate rift basin along a passive margin.Our work thus argues against a Grenvillian orogen’s existence in the Yangtze Block.In view of the subsequent Neoproterozoic subduction-related magmatism in the region,we suggest that the Yangtze Block might have been along the periphery of the Rodinia.
基金supported by the Special Fund for Basic Scientific Research of Central Colleges,Chang'an University(No.CHD2010ZY005)the National Natural Science Foundation of China(No. 41273033)the China Regional Geological Survey (No.XJZBKD2008-04,XJQDZ2009-03,1212011120516, 1212011220619)
文摘Late Paleozoic post-collisional granitoids are widespread in West Junggar, as well as northern Xinjiang. As a representative of those intrusions, the Jietebutiao granite occurs in the southwestern margin of the West Junggar （northwest China）, and is mainly composed of mid-coarse- grained monzogranite and syenogranite. In the present study, we report the results of high-precision zircon laser-ablation-inductively-coupled plasma mass-spectrometry U-Pb dating on the Jietebutiao granite for the first time, and yield weighted mean 2~~pb/23SU ages of 287 ＋ 9 Ma and 278 ~ 3 Ma for monzogranite and syenogranite, respectively. The Jietebutiao granite has a pronounced A-type affinity; it is metaluminous to slightly peraluminous; has a high-K calc-alkaline composition; high concentrations of Na20 ＋ I（20, varying from 6.8 to 8.5 wt%; high FeOt/MgO; 10 000Ga/AI ratios, a low CaO, MgO, and TiO2 content; enriched in some large ion lithophile elements （LILE, such as Rb and Th） and high field strength elements （HFSE, such as Zr, Hf, and Y）; and depleted in Sr, Ba, and Ti. In addition, the granite has a relatively high rare earth element （REE） content （except for Eu）, with significant negative Eu anomalies （Eu/Eu＊ = 0.01-0.72）, and showing slight tetrad REE patterns and non-charge and radius controlled （CHARAC） trace element behavior. Petrographic, geochemical, and geochronological data suggest that the parental magma of Jietebutiao intrusions are of mixed origin, and are most probably formed by the interaction between the lower crust- and mantle-derived magmas in the Early Permian post-collisional tectonic setting. The basaltic magmas underplated and interacted with the lower crust that was dominated by deeply buried arc （and back-arc basin） series and the oceanic crust formed in the Paleozoic, and then triggered the partial melting of the juvenile lower crust, producing voluminous granitic melts and forming the Jietebutiao A2-type monzogranites, with the lithospheric mantle progressively thinning and rifting to form Al-type granites, such as syenogranites, in the Jietebutiao pluton. This further proves the important contribution of Late Paleozoic granitic magmatism in terms of vertical crustal growth in northern Xinjiang.
基金the State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang(No.2020Z03)the National Key R&D Program of China(Nos.2016YFC0600408,2019YFA0708400)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB41020102)。
文摘The Early Cretaceous aluminous A-type granites in the Lower Yangtze River belt(LYRB)can provide important insights into the Mesozoic magmatism in eastern China,but their origin remains highly controversial.In this study,radiogenic Ca-Nd isotopic analysis was performed for syenite porphyry and alkali-feldspar granite porphyry of the Yangshan pluton,a typical aluminous A-type granitic intrusion in the LYRB,to constrain its source and geodynamic setting.The results show thatε_(Ca)(126 Ma),ε_(Nd)(126 Ma)and K/Ca_(source) of the syenite porphyry range from-0.24 to+0.96,-7.2 to-6.0,and 0.31 to 1.26,respectively.The corresponding values for the alkali-feldspar granite porphyry range from 0.26 to 0.84,-8.0 to-6.1,and 0.79 to 1.08,respectively.Binary mixing modeling indicates that they were originated from the same sources with different proportion,namely,a mixing of 50%to 75%Neoproterozoic crust and 50%to 25%asthenospheric mantle.Together with previous works,we propose that the Early Cretaceous subduction of the ridge between the Pacific and Izanagi plates was responsible for the formation of the aluminous A-type granites in the LYRB.
基金financially supported by the Key R&D Program of China(Grant No.2017YFC0602402)the Innovationdriven Plan of Central South University,China(Grant No.2015CX008)+2 种基金the China Postdoctoral Science Foundation(Grant No.2017M622597)Open Research Fund Program of Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education(Grant No.2019YSJS23)the Natural Science Foundation of Hunan Province(Grant No.2017JJ3138)
文摘The Jiuyishan complex massif,located in the northern section of the Nanling region,is a combination of five plutons,namely,the Xuehuading,Jinjiling,Pangxiemu,Shaziling and Xishan plutons.Whole-rock geochemistry,Imineral electron microprobe analysis,zircon U-Pb dating and Hf isotope analysis were carried out for the Jinjiling and Pangxiemu plutons.The zircon U-Pb dating yields weighted mean ages of 152.9±0.9 Ma for the Jinjiling pluton and 151.7±1.5 Ma for the Pangxiemu pluton,with a narrow gap between them.The Jinjiling and Pangxiemu plutons both have geochemical characteristics of high SiO2,Al2 O3,Na2 O,K2 O and low TiO2,MgO,CaO,P2 O5 contents,with intense depletions in Sr,Ba,Ti,Eu and enrichments in Ga,FeoOT and HFSE,and these characteristics reflect an A-type affinity.From the Jinjiling to the Pangxiemu plutons,the mineral composition of mica changes from lepidomelane to zinnwaldite,with increases in F,Li2 O and Rb2 O contents.The mineral composition of zircon changes from low Zr/Hf to high Zr/Hf,with increasing HfO2,P2 O5 and UO2+ThO2+Y2 O3 contents.The mineral compositions of feldspar indicate that the Pangxiemu pluton contains more alkali feldspar than the Jinjiling pluton.The whole-rock geochemistry and mineral compositions reveal a higher degree of differentiation for the Pangxiemu pluton.The nearly uniformεHf(t)indicates the same source region for the two plutons:both were derived from partial melting of the lower crust,with small contributions of mantle materials.In addition,higher F,lower Nb/Ta and Zr/Hf ratios in the Pangxiemu Pluton suggest a closer relationship with the rare metal mineralization than for the Jinjiling pluton.
基金supported by the research program of Heilongjiang province (Nos. SDKC2017030 and HDKK201701)
文摘Early Ordovician A-type granites in the northeastern(NE) Songnen Block NE China were studied to better understand the geodynamic settings in this region.This research presents new zircon U–Pb ages and wholerock geochemical data for the Early Ordovician granites in the NE Songnen Block. Zircon U–Pb dating indicates that the granite in the Cuibei, Hongxing, and Meixi areas in the NE Songnen Block formed in the Early Ordovician with ages of 471–479 Ma. The granites show geochemical characteristics of high SiO2 and K2 O compositions and low FeOT, MgO, CaO, and P2 O5 compositions. They belong to a high K calc-alkaline series and display a weak peraluminous featurPe with A/CNK values of 0.98–1.14. The rocks have aREE composition of 249.98–423.94 ppm,and are enriched in LREE with(La/Yb)Nvalues of2.87–9.87, and display obvious Eu anomalies(d Eu =0.01–0.29). Trace elements of the studied granites are characterized by enrichment in Rb, Th, U, Pb, Hf, and Sm,and depletion of Ba, Nb, Ta, and Sr. They display geochemical features of high Zr +Y + Nb+Ce values(324–795 ppm) and Ga/Al ratios consistent with A-type granites. Based on particular geochemical features, such as high Rb/Nb(7.98–24.19) and Y/Nb(1.07–3.43), the studied A-type granites can be further classified as an A2-type subgroup. This research indicates that the Early Ordovician A-type granites were formed by the partial melting of ancient crust in an extensional setting. Lower Sr/Y and(Ho/Yb)Nratios indicate that plagioclase and amphibole are residual in the source, and garnet is absent, implying that the magma was generated at low levels of pressure. By contrast, the contemporaneous granites in the SE Xing'an Block suggest a subduction-related tectonic setting, and its adakitic property indicates a thickened continental crust.We suggest that the Paleo-Asian Ocean plate between the Xing'an and Songnen blocks subducted northward during the Early Ordovician. Meanwhile, the NE Songnen Block was exposed to a passive continental margin tectonic setting.
