GeoPyTool is an open source application developed for geological calculations and plots,such as geochemical classification,parameter calculation,basic statistical analysis and diagrams for structural geology.More than...GeoPyTool is an open source application developed for geological calculations and plots,such as geochemical classification,parameter calculation,basic statistical analysis and diagrams for structural geology.More than acting as a link from raw data stored in Microsoft Excel■(MS Excel)files to vector graphic files,GeoPyTool includes recently developed routines that have not been included in previous software,such as the calculation of the Ce(Ⅳ)/Ce(Ⅲ)ratio for zircons as a method to examine the temporal evolution of oxygen fugacity in the magmatic source for igneous rocks,and the temperature calculator with titanium in zircon and zirconium in rutile.Besides these routines,GeoPyTool also allows users to load any figure from articles or books as a base map.As a Python-based crossplatform program,GeoPyTool works on Windows?,MacOS X?and GNU/Linux.GeoPyTool can do the whole process from data to results without the dependence of Microsoft Excel?,CorelDraw?and other similar software.It takes Excel?XLSX and CSV(Comma Separated Value)as the formats of both the input data source files and the output calculation results files.The figures generated by GeoPyTool can be saved as portable network graphics(PNG),scalable vector graphics(SVG)or portable document format(PDF).Another highlight of GeoPyTool is the multilingual support,the official versio n of GeoPyTool supports both Chinese and English,and additional languages can be loaded through interface files.GeoPyTool is still in the development stage and will be expanded with further geochemical and structural geology routines.As an open source project,all source code of GeoPyTool are accessible on Github(https://github.com/GeoPyTool/GeoPyTool).Users with Python experience can join in the development team and build more complex functions expanding the capabilities of GeoPyTool.展开更多
Late Mesozoic igneous intrusions and extensional structures in Carboniferous to Permian sequences in the SW Fujian region acted as important controls on the localisation of Fe-polymetallic de-posits.Here we document t...Late Mesozoic igneous intrusions and extensional structures in Carboniferous to Permian sequences in the SW Fujian region acted as important controls on the localisation of Fe-polymetallic de-posits.Here we document the identification of extensional deformation at shallow crustal levels and syn-tectonic granites related to normal faults.Based on spatial distribution and structural features,the extensional deformation can be divided into cover-only and basement-intersecting styles.A series of syn-tectonic plutons were emplaced into the footwall of normal faults.Representative samples of the Tangquan Granite have high SiO2(66.4 wt.%-73.9 wt.%)assays and Mg#values(37-59).The samples also have relatively homogenous initial 87Sr/86Sr(0.7083-0.7089)andεNd(-9.2--10.2)values.Geochemical and isotopic evidences indicate that the Tangquan granite originates from a hybrid source including lower crustal-derived felsic and lithospheric mantle-derived mafic magmas.Zircon U-Pb dating indicates that the granodiorite phase from the pluton crystallised at 161±4 Ma and the monzogranite phase crystallised at 159±1 Ma.Combined with the granitic rocks in a wider region of SE China,the widespread granitic magmatism and polymetallic mineralisation have been synchronous during the Late Mesozoic,probably resulting from extensional tectonics related to the lithospheric thinning.展开更多
Two Neoarchean alkaline feldspar-rich granites sourced from partially melted granulite-facies granodioritic orthogneiss have been here recognised in the eastern part of the North China Block(NCB).These poorly foliated...Two Neoarchean alkaline feldspar-rich granites sourced from partially melted granulite-facies granodioritic orthogneiss have been here recognised in the eastern part of the North China Block(NCB).These poorly foliated granites have previously been assumed to be Mesozoic in age and never dated,and so their significance has not been recognised until now.The first granite(AG1)is a porphyritic syenogranite with megacrystic K-feldspar,and the second(AG2)is a quartz syenite with perthitic megacryst.Zircons from the granites yield LA-ICP-MS U-Pb ages of 2499±10 Ma(AG1),and 2492±28 Ma(AG2),which are slightly younger than the granodioritic orthogneiss that they intrude with a crystallisation U-Pb age of 2537±34 Ma.The younger granites have higher assays for SiO_(2)(71.91%for AG1 and 73.22%for AG2)and K_(2)O(7.52%for AG1 and 8.37%for AG2),and much lower assays for their other major element than the granodioritic orthogneiss.All of the granodioritic orthogneiss and granite samples have similar trace element patterns,with depletion in Th,U,Nb,and Ti and enrichment in Rb,Ba,K,La,Ce,and P.This indicates that the granites are derived from the orthogneiss as partial melts.Although they exhibit a similar REE pattern,the granites have much lower total REE contents(30.97×10^(−6) for AG1,and 25.93×10^(−6) for AG2),but pronounced positive Eu anomalies(Eu/Eu^(*)=8.57 for AG1 and 27.04 for AG2).The granodioritic orthogneiss has an initial ^(87)Sr/^(86)Sr ratio of 0.70144,εNd(t)value of 3.5,and εHf(t)values ranging from−3.2 to+2.9.The orthogneiss is a product of fractional crystallisation from a dioritic magma,which was derived from a mantle source contaminated by melts derived from a felsic slab.By contrast,the AG1 sample has an initial ^(87)Sr/^(86)Sr ratio of 0.6926 that is considered too low in value,εNd(t)value of 0.3,andεHf(t)values between+0.57 and+3.82;whereas the AG2 sample has an initial ^(87)Sr/^(86)Sr ratio of 0.70152,εNd(t)value of 1.3,andεHf(t)values between+0.5 and+14.08.These assays indicate that a Sr-Nd-Hf isotopic disequilibrium exists between the granite and granodioritic orthogneiss.The elevatedεHf(t)values of the granites can be explained by the involvement of Hf-bearing minerals,such as orthopyroxene,amphibole,and biotite,in anatectic reactions in the granodioritic orthogneiss.Based on the transitional relationship between the granites and granodioritic orthogneiss and the geochemical characteristics mentioned above,it is concluded that the granites are the product of rapid partial-melting of the granodioritic orthogneiss after granulite-facies metamorphism,and their crystallisation age of about 2500 Ma provides the minimum age of the metamorphism.This about 2500 Ma tectonic-metamorphic event in NCB is similar to the other cratons in India,Antarctica,northern and southern Australia,indicating a possible connection between these cratons during the Neoarchean.展开更多
The study of metallogeny includes origin,development,modification,and preservation of mineralisation.The understanding of temporal evolution,and post-mineralisation modification and preservation of mineralisation are ...The study of metallogeny includes origin,development,modification,and preservation of mineralisation.The understanding of temporal evolution,and post-mineralisation modification and preservation of mineralisation are vital for building metallogenic theory and mineral prospecting,but they remain poorly understood and controversial.The Zaozigou deposit is the largest Au deposit in the West Qinling Orogen of central China with a resource of 142 t Au,and offers an excellent opportunity for deciphering the post-mineralisation exhumation and preservation of Au deposit in orogens.Here,we present integrated results from zircon U-Pb(ZUPb),apatite U-Pb(AUPb),apatite fission-track(AFT)and apatite(U-Th-Sm)/He(AHe)dating,thermal history modelling,biotite thermobarometer,and pyrite thermoelectricity of the deposit.The aims of the study are to decipher the temporal history,and post-mineralisation tectonic evolution and exhumation,and to evaluate the degree of exhumation and preservation potential of the deposit.Integrating the newly determined ZUPb(ca.242–238 and 218–201 Ma),AUPb(ca.247–235 Ma),AFT(ca.237–186 Ma),and AHe(ca.131–52 Ma)ages with multiple geo-thermochronological dates published from the Zaozigou deposit,major magmatic and hydrothermal events are recognised during ca.250–233 and230–203 Ma,with two Au mineralisation being deposited at ca.230 and 211 Ma.The Zaozigou area underwent rapid postmagma cooling during ca.250–228 Ma,rapid hydrothermal cooling at ca.219–211 Ma,and episodic post-Triassic cooling pulses.Thermal history modelling indicates rapid cooling at ca.210–170 Ma,slow reheating at ca.170–60 Ma,and enhanced cooling during ca.60–35 and 20–9 Ma at the Zaozigou deposit.In conjunction with the Triassic to Cenozoic tectonic evolution of the West Qinling Orogen,the ca.250–233 Ma magmatism,ca.230 Ma Au mineralisation,and ca.250–228 Ma rapid postmagma cooling are related to the northward subduction of the Mianlue Ocean(Paleo-Tethys Ocean).The ca.211 Ma Au mineralisation and rapid hydrothermal cooling during ca.210–170 Ma are correlated with the collision between the South Qinling Belt and South China Block during ca.220–210 Ma and the post-collisional gravitational collapse during the Jurassic.Prolonged reheating during ca.170–60 Ma is associated with the unconformable deposition of coeval sedimentary sequences.The ca.60–35 and 20–9 Ma enhanced cooling relates to the India-Eurasia collision,the northward growth of Tibetan Plateau,and the intensive East Asian summer monsoon during the Cenozoic.~28%–68%amounts of the Au orebodies in the Zaozigou deposit have been eroded away.In contrast with the estimated post-mineralisation exhumation depth of~4.8 km and reported ore-forming depth of 2–6 km,local portions of the deposit are indicated to be preserved to a depth of over 1 km for Au exploration.Timely supply of post-mineralisation sediments and regional peneplanation during the Jurassic to Cenozoic are important factors for preservation of the deposit.During rapid uplift and exhumation of orogens,sediment-hosted Au mineralisation has highly prospective for prospecting.The study also highlights that multidisciplinary approaches of geo-thermochronology,thermobarometer,and thermoelectricity are effective tools in determining post-mineralisation modification and preservation of orebodies.展开更多
基金supported by the National Key Research and Development Program of China(No.2016YFC0600509)the National Natural Science Foundation of China(No.41772069)+1 种基金the China Geological Survey Program(Nos.1212011085490,12120113089600,12120114028701)the Fundamental Research Funds for the Central University(No.2652017259)
文摘GeoPyTool is an open source application developed for geological calculations and plots,such as geochemical classification,parameter calculation,basic statistical analysis and diagrams for structural geology.More than acting as a link from raw data stored in Microsoft Excel■(MS Excel)files to vector graphic files,GeoPyTool includes recently developed routines that have not been included in previous software,such as the calculation of the Ce(Ⅳ)/Ce(Ⅲ)ratio for zircons as a method to examine the temporal evolution of oxygen fugacity in the magmatic source for igneous rocks,and the temperature calculator with titanium in zircon and zirconium in rutile.Besides these routines,GeoPyTool also allows users to load any figure from articles or books as a base map.As a Python-based crossplatform program,GeoPyTool works on Windows?,MacOS X?and GNU/Linux.GeoPyTool can do the whole process from data to results without the dependence of Microsoft Excel?,CorelDraw?and other similar software.It takes Excel?XLSX and CSV(Comma Separated Value)as the formats of both the input data source files and the output calculation results files.The figures generated by GeoPyTool can be saved as portable network graphics(PNG),scalable vector graphics(SVG)or portable document format(PDF).Another highlight of GeoPyTool is the multilingual support,the official versio n of GeoPyTool supports both Chinese and English,and additional languages can be loaded through interface files.GeoPyTool is still in the development stage and will be expanded with further geochemical and structural geology routines.As an open source project,all source code of GeoPyTool are accessible on Github(https://github.com/GeoPyTool/GeoPyTool).Users with Python experience can join in the development team and build more complex functions expanding the capabilities of GeoPyTool.
基金This study is financially supported by the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0804)Major Research Plan of the National Natural Science Foundation of China(No.91755215)+5 种基金National Natural Science Foundation of China(No.41703037)the National Key R&D Plan(No.2018YFC0603801)the Open Research Pro-ject from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing(No.GPMR201816)the Fundamental Research Funds for the Central Public Welfare Research Institutes(Nos.KK1914,KK2013)the Chinese Geological Survey Program(Nos.DD20201173,DD20190379)Key Laboratory of Regional Geology and Mineralization,Hebei GEO University(No.HGU-RGMKF192).
文摘Late Mesozoic igneous intrusions and extensional structures in Carboniferous to Permian sequences in the SW Fujian region acted as important controls on the localisation of Fe-polymetallic de-posits.Here we document the identification of extensional deformation at shallow crustal levels and syn-tectonic granites related to normal faults.Based on spatial distribution and structural features,the extensional deformation can be divided into cover-only and basement-intersecting styles.A series of syn-tectonic plutons were emplaced into the footwall of normal faults.Representative samples of the Tangquan Granite have high SiO2(66.4 wt.%-73.9 wt.%)assays and Mg#values(37-59).The samples also have relatively homogenous initial 87Sr/86Sr(0.7083-0.7089)andεNd(-9.2--10.2)values.Geochemical and isotopic evidences indicate that the Tangquan granite originates from a hybrid source including lower crustal-derived felsic and lithospheric mantle-derived mafic magmas.Zircon U-Pb dating indicates that the granodiorite phase from the pluton crystallised at 161±4 Ma and the monzogranite phase crystallised at 159±1 Ma.Combined with the granitic rocks in a wider region of SE China,the widespread granitic magmatism and polymetallic mineralisation have been synchronous during the Late Mesozoic,probably resulting from extensional tectonics related to the lithospheric thinning.
基金The CAGS Research Fund(YYWF201715,YK1608)the project of China Geological Survey(DD20190437)financially support this study and contribution.
文摘Two Neoarchean alkaline feldspar-rich granites sourced from partially melted granulite-facies granodioritic orthogneiss have been here recognised in the eastern part of the North China Block(NCB).These poorly foliated granites have previously been assumed to be Mesozoic in age and never dated,and so their significance has not been recognised until now.The first granite(AG1)is a porphyritic syenogranite with megacrystic K-feldspar,and the second(AG2)is a quartz syenite with perthitic megacryst.Zircons from the granites yield LA-ICP-MS U-Pb ages of 2499±10 Ma(AG1),and 2492±28 Ma(AG2),which are slightly younger than the granodioritic orthogneiss that they intrude with a crystallisation U-Pb age of 2537±34 Ma.The younger granites have higher assays for SiO_(2)(71.91%for AG1 and 73.22%for AG2)and K_(2)O(7.52%for AG1 and 8.37%for AG2),and much lower assays for their other major element than the granodioritic orthogneiss.All of the granodioritic orthogneiss and granite samples have similar trace element patterns,with depletion in Th,U,Nb,and Ti and enrichment in Rb,Ba,K,La,Ce,and P.This indicates that the granites are derived from the orthogneiss as partial melts.Although they exhibit a similar REE pattern,the granites have much lower total REE contents(30.97×10^(−6) for AG1,and 25.93×10^(−6) for AG2),but pronounced positive Eu anomalies(Eu/Eu^(*)=8.57 for AG1 and 27.04 for AG2).The granodioritic orthogneiss has an initial ^(87)Sr/^(86)Sr ratio of 0.70144,εNd(t)value of 3.5,and εHf(t)values ranging from−3.2 to+2.9.The orthogneiss is a product of fractional crystallisation from a dioritic magma,which was derived from a mantle source contaminated by melts derived from a felsic slab.By contrast,the AG1 sample has an initial ^(87)Sr/^(86)Sr ratio of 0.6926 that is considered too low in value,εNd(t)value of 0.3,andεHf(t)values between+0.57 and+3.82;whereas the AG2 sample has an initial ^(87)Sr/^(86)Sr ratio of 0.70152,εNd(t)value of 1.3,andεHf(t)values between+0.5 and+14.08.These assays indicate that a Sr-Nd-Hf isotopic disequilibrium exists between the granite and granodioritic orthogneiss.The elevatedεHf(t)values of the granites can be explained by the involvement of Hf-bearing minerals,such as orthopyroxene,amphibole,and biotite,in anatectic reactions in the granodioritic orthogneiss.Based on the transitional relationship between the granites and granodioritic orthogneiss and the geochemical characteristics mentioned above,it is concluded that the granites are the product of rapid partial-melting of the granodioritic orthogneiss after granulite-facies metamorphism,and their crystallisation age of about 2500 Ma provides the minimum age of the metamorphism.This about 2500 Ma tectonic-metamorphic event in NCB is similar to the other cratons in India,Antarctica,northern and southern Australia,indicating a possible connection between these cratons during the Neoarchean.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.42202077,42473029)the Natural Science Foundation of Gansu Province(Grant Nos.22JR5RA440,20JR10RA630)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.LZUJBKY-2022-42)the Guiding Special Funds of“Double First-Class(First-Class University&First-Class Disciplines)”of Lanzhou University,China(Grant No.561119201)。
文摘The study of metallogeny includes origin,development,modification,and preservation of mineralisation.The understanding of temporal evolution,and post-mineralisation modification and preservation of mineralisation are vital for building metallogenic theory and mineral prospecting,but they remain poorly understood and controversial.The Zaozigou deposit is the largest Au deposit in the West Qinling Orogen of central China with a resource of 142 t Au,and offers an excellent opportunity for deciphering the post-mineralisation exhumation and preservation of Au deposit in orogens.Here,we present integrated results from zircon U-Pb(ZUPb),apatite U-Pb(AUPb),apatite fission-track(AFT)and apatite(U-Th-Sm)/He(AHe)dating,thermal history modelling,biotite thermobarometer,and pyrite thermoelectricity of the deposit.The aims of the study are to decipher the temporal history,and post-mineralisation tectonic evolution and exhumation,and to evaluate the degree of exhumation and preservation potential of the deposit.Integrating the newly determined ZUPb(ca.242–238 and 218–201 Ma),AUPb(ca.247–235 Ma),AFT(ca.237–186 Ma),and AHe(ca.131–52 Ma)ages with multiple geo-thermochronological dates published from the Zaozigou deposit,major magmatic and hydrothermal events are recognised during ca.250–233 and230–203 Ma,with two Au mineralisation being deposited at ca.230 and 211 Ma.The Zaozigou area underwent rapid postmagma cooling during ca.250–228 Ma,rapid hydrothermal cooling at ca.219–211 Ma,and episodic post-Triassic cooling pulses.Thermal history modelling indicates rapid cooling at ca.210–170 Ma,slow reheating at ca.170–60 Ma,and enhanced cooling during ca.60–35 and 20–9 Ma at the Zaozigou deposit.In conjunction with the Triassic to Cenozoic tectonic evolution of the West Qinling Orogen,the ca.250–233 Ma magmatism,ca.230 Ma Au mineralisation,and ca.250–228 Ma rapid postmagma cooling are related to the northward subduction of the Mianlue Ocean(Paleo-Tethys Ocean).The ca.211 Ma Au mineralisation and rapid hydrothermal cooling during ca.210–170 Ma are correlated with the collision between the South Qinling Belt and South China Block during ca.220–210 Ma and the post-collisional gravitational collapse during the Jurassic.Prolonged reheating during ca.170–60 Ma is associated with the unconformable deposition of coeval sedimentary sequences.The ca.60–35 and 20–9 Ma enhanced cooling relates to the India-Eurasia collision,the northward growth of Tibetan Plateau,and the intensive East Asian summer monsoon during the Cenozoic.~28%–68%amounts of the Au orebodies in the Zaozigou deposit have been eroded away.In contrast with the estimated post-mineralisation exhumation depth of~4.8 km and reported ore-forming depth of 2–6 km,local portions of the deposit are indicated to be preserved to a depth of over 1 km for Au exploration.Timely supply of post-mineralisation sediments and regional peneplanation during the Jurassic to Cenozoic are important factors for preservation of the deposit.During rapid uplift and exhumation of orogens,sediment-hosted Au mineralisation has highly prospective for prospecting.The study also highlights that multidisciplinary approaches of geo-thermochronology,thermobarometer,and thermoelectricity are effective tools in determining post-mineralisation modification and preservation of orebodies.
