Objective A large number of Mesozoic volcano-sedimentary basins is distributed in southern Jilin Province,China,and filled with a great set of coal-bearing strata.According to the petroleum resources evaluation by pre...Objective A large number of Mesozoic volcano-sedimentary basins is distributed in southern Jilin Province,China,and filled with a great set of coal-bearing strata.According to the petroleum resources evaluation by previous researchers,these basins have decent exploration potential(Wang Dandan et al.,2017).The Liuhe Basin is one of the展开更多
We report U-Pb dating of zircon,as well as geochemical and Hf isotope data,in order to constrain the formation time,magma source,and tectonic setting of granite porphyry dykes in the Xicha gold-(silver)district in sou...We report U-Pb dating of zircon,as well as geochemical and Hf isotope data,in order to constrain the formation time,magma source,and tectonic setting of granite porphyry dykes in the Xicha gold-(silver)district in southern Jilin Province,Northeast China.The zircon grains are euhedral-subhedral,display oscillatory growth zoning and have Th/U ratios varying between 0.11 and 0.78,which together imply a magmatic origin.The dating results indicate the porphyry formed in the Early Cretaceous(122±1 Ma)and it contains SiO2=70.64-72.31 wt%,Al2O3-=13.99-14.64 wt%,K2O+Na2O=6.96-7.81 wt%K2O/Na2O=1.24-2.10,and A/CNK=1.11-1.41.Chemically,the porphyry belongs to a high-K calc-alkaline S-type granite.Chondrite-normalized rare earth elements(REE)patterns show LREE enrichment,light rare earth elements(LREE)/heavy rare earth elements(HREE)=9.93-11.97(La/Yb)N=11.08-15.16,and d Eu=0.69-0.95.On the trace element spider diagram,large ion lithophile elements such as Rb,Ba,K,Th,and U are enriched,whereas the high field strength elements Ti and P are depleted.The e Hf(t)values of zircon from the granite porphyry vary between-17.1 and-13.2,and their Hf two-stage model ages vary from 2.01 to 2.26 Ga,implying that the magma was derived from partial melting of old lower crust.The granite porphyry dykes and many A-type granites in the region formed at the same time,suggesting an extensiona environment.The combination of the occurrence of strong magmatism,large-scale mineralization,and extensiona tectonics throughout much of Eastern China indicate that the Early Cretaceous was a period of significant lithospheric thinning.The southern Jilin Province,therefore,experienced lithospheric thinning during the Early Cretaceous.展开更多
基金supported by the research project of Exploration Department of Jilin Oilfield Company Ltd. (grant No. JLYTJS11W23FW2275)
文摘Objective A large number of Mesozoic volcano-sedimentary basins is distributed in southern Jilin Province,China,and filled with a great set of coal-bearing strata.According to the petroleum resources evaluation by previous researchers,these basins have decent exploration potential(Wang Dandan et al.,2017).The Liuhe Basin is one of the
基金supported by the Undergraduate Institutions Basic Scientific Research Foundation of Heilongjiang Province(Hkdcx201805)the Natural Science Foundation of Heilongjiang Province,China(QC2017035)the National Nature Science of Foundation of China(41272093)。
文摘We report U-Pb dating of zircon,as well as geochemical and Hf isotope data,in order to constrain the formation time,magma source,and tectonic setting of granite porphyry dykes in the Xicha gold-(silver)district in southern Jilin Province,Northeast China.The zircon grains are euhedral-subhedral,display oscillatory growth zoning and have Th/U ratios varying between 0.11 and 0.78,which together imply a magmatic origin.The dating results indicate the porphyry formed in the Early Cretaceous(122±1 Ma)and it contains SiO2=70.64-72.31 wt%,Al2O3-=13.99-14.64 wt%,K2O+Na2O=6.96-7.81 wt%K2O/Na2O=1.24-2.10,and A/CNK=1.11-1.41.Chemically,the porphyry belongs to a high-K calc-alkaline S-type granite.Chondrite-normalized rare earth elements(REE)patterns show LREE enrichment,light rare earth elements(LREE)/heavy rare earth elements(HREE)=9.93-11.97(La/Yb)N=11.08-15.16,and d Eu=0.69-0.95.On the trace element spider diagram,large ion lithophile elements such as Rb,Ba,K,Th,and U are enriched,whereas the high field strength elements Ti and P are depleted.The e Hf(t)values of zircon from the granite porphyry vary between-17.1 and-13.2,and their Hf two-stage model ages vary from 2.01 to 2.26 Ga,implying that the magma was derived from partial melting of old lower crust.The granite porphyry dykes and many A-type granites in the region formed at the same time,suggesting an extensiona environment.The combination of the occurrence of strong magmatism,large-scale mineralization,and extensiona tectonics throughout much of Eastern China indicate that the Early Cretaceous was a period of significant lithospheric thinning.The southern Jilin Province,therefore,experienced lithospheric thinning during the Early Cretaceous.
