GeoPyTool:A cross-platform software solution for common geological calculations and plots

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.

Archean (about 2500 Ma) anatexis in eastern North China Block

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.

Late Jurassic Intracontinental Extension and Related Mineralisation in Southwestern Fujian Province of SE China:Insights from Deformation and Syn-Tectonic Granites

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.