The Xilamulun molybdenum polymetallic metallogenic belt in eastern Inner Mongolia forms one of the most important Mo metallogenic belts in northeastern China. The Dongshanwan porphyry Mo-W polymetallic deposit, in the...The Xilamulun molybdenum polymetallic metallogenic belt in eastern Inner Mongolia forms one of the most important Mo metallogenic belts in northeastern China. The Dongshanwan porphyry Mo-W polymetallic deposit, in the northeastern part of the Xilamulun metallogenic belt, occurs along the periphery of a granite porphyry and consists of Mo-W-Ag sulfide and oxide disseminations and veinlets in hydrothermal assemblages. LA-ICP-MS zircon U-Pb dating of the Dongshanwan granite porphyry yields a crystallization age of 142.15± 0.91 Ma, whereas molybdenite Re-Os isotopic dating model ages are of 139.9–141.5 Ma and an isochron age is of 140.5± 3.2 Ma（MSWD=1.2）. The age consistency indicates that the Dongshanwan deposit was a product of Early Cretaceous magmatism. The Dongshanwan granite porphyry is a high-alkali high-potassium intrusion and has high SiO_2（75.39 wt.%–76.15 wt.%）, low Al_2O_3（12 wt.%–13 wt.%）, Ba, Ti, P, and Sr contents, with negative Eu anomalies. The Y/Nb ratios are comparable to those of average continental crust and island arc basalts, corresponding to type-A2 granites. Our geochemical data indicate that the granite porphyry emplaced in an Early Cretaceous post-orogenic extensional environment following Mongol-Okhotsk oceanic subduction and subsequent continental collision.展开更多
Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addi...Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addition,to avoid the bias of detrital zircon ages caused by variations in zircon fertility,we collected 1709 whole rock zirconium content values(ppm)from granitic rocks with different ages in the North China Craton(NCC).Based on mean Zr content of granitic rocks in each age,these granitic rocks can be divided into four groups:Group A consists of Jurassic,Group B consists of Paleozoic,Neo-Mesoproterozoic and Neoarchean,Group C consists of Early Cretaceous and Triassic,and Group D consists of Paleoproterozoic.This research assigns to these groups zircon fertility factors(ZFF)of 1,1.4,1.8 and 2.2.The U-Pb age of detrital zircons from Late Jurassic sediments corrected by ZFF is statistically analyzed(K-S test,similarity,crosscorrelation,linkeness,and multidimensional scaling).And combining with paleocurrent and paleogeography,we construct two source-to-sink systems:(1)Jiaodong uplift and Sulu Orogenic Belt as the source area and the North Yellow Sea Basin as the sink area;(2)Liaodong Peninsula as the source area and the North Yellow Sea Basin as the sink area.展开更多
During the Late Paleozoic-Early Mesozoic Era,the sediment transport system and tectonic regime in the southeastern margin of the South China Block(SESCB)all changed,significantly affected by the Paleo-Pacific subducti...During the Late Paleozoic-Early Mesozoic Era,the sediment transport system and tectonic regime in the southeastern margin of the South China Block(SESCB)all changed,significantly affected by the Paleo-Pacific subduction.However,controversy exists about the Paleo-Pacific subduction's initiation time.This study uses detrital zircon U-Pb ages to discuss the Late Triassic source-tosink system in the SESCB.It provides some references for the Paleo-Pacific subduction process based on crucial age information and zircons'trace elements.The paleogeography and similarity of detrital zircon age distribution indicate that three sinks were found in the SESCB during the Late Triassic:1.the Yangchun-Kaiping-Gaoming area,comprising major age ranges of 260-220,460-400,and 1200-800 Ma,which might be sourced from the Yunkai terrane;2.the Jiexi-Kanshi-Nanjing area,characterized by the significant age component of 2000-1800 Ma,which corresponded to the Wuyi terrane;3.the Xinan area,consisting of significant age groups of 290-250 and 380-320 Ma,which might be sourced from the magmatic rocks formed by the Huinan Movement and Paleo-Pacific subduction.Note that 290-250 Ma zircons were widely distributed in the Upper Triassic strata,and their trace elements suggested the existence of a magmatic arc near the SESCB during the 290-250 Ma.Thus,we propose that the Paleo-Pacific subduction might have begun in the Early Permian.展开更多
基金supported by the Opening Foundation of the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(No.GPMR201307)
文摘The Xilamulun molybdenum polymetallic metallogenic belt in eastern Inner Mongolia forms one of the most important Mo metallogenic belts in northeastern China. The Dongshanwan porphyry Mo-W polymetallic deposit, in the northeastern part of the Xilamulun metallogenic belt, occurs along the periphery of a granite porphyry and consists of Mo-W-Ag sulfide and oxide disseminations and veinlets in hydrothermal assemblages. LA-ICP-MS zircon U-Pb dating of the Dongshanwan granite porphyry yields a crystallization age of 142.15± 0.91 Ma, whereas molybdenite Re-Os isotopic dating model ages are of 139.9–141.5 Ma and an isochron age is of 140.5± 3.2 Ma（MSWD=1.2）. The age consistency indicates that the Dongshanwan deposit was a product of Early Cretaceous magmatism. The Dongshanwan granite porphyry is a high-alkali high-potassium intrusion and has high SiO_2（75.39 wt.%–76.15 wt.%）, low Al_2O_3（12 wt.%–13 wt.%）, Ba, Ti, P, and Sr contents, with negative Eu anomalies. The Y/Nb ratios are comparable to those of average continental crust and island arc basalts, corresponding to type-A2 granites. Our geochemical data indicate that the granite porphyry emplaced in an Early Cretaceous post-orogenic extensional environment following Mongol-Okhotsk oceanic subduction and subsequent continental collision.
基金supported by the National Natural Science Foundation of China(Nos.41872101 and 41790453-4)。
文摘Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addition,to avoid the bias of detrital zircon ages caused by variations in zircon fertility,we collected 1709 whole rock zirconium content values(ppm)from granitic rocks with different ages in the North China Craton(NCC).Based on mean Zr content of granitic rocks in each age,these granitic rocks can be divided into four groups:Group A consists of Jurassic,Group B consists of Paleozoic,Neo-Mesoproterozoic and Neoarchean,Group C consists of Early Cretaceous and Triassic,and Group D consists of Paleoproterozoic.This research assigns to these groups zircon fertility factors(ZFF)of 1,1.4,1.8 and 2.2.The U-Pb age of detrital zircons from Late Jurassic sediments corrected by ZFF is statistically analyzed(K-S test,similarity,crosscorrelation,linkeness,and multidimensional scaling).And combining with paleocurrent and paleogeography,we construct two source-to-sink systems:(1)Jiaodong uplift and Sulu Orogenic Belt as the source area and the North Yellow Sea Basin as the sink area;(2)Liaodong Peninsula as the source area and the North Yellow Sea Basin as the sink area.
基金supported by the National Natural Science Foundation of China(No.41872101)the Graduate Innovation Fund of Jilin University(No.2022046)。
文摘During the Late Paleozoic-Early Mesozoic Era,the sediment transport system and tectonic regime in the southeastern margin of the South China Block(SESCB)all changed,significantly affected by the Paleo-Pacific subduction.However,controversy exists about the Paleo-Pacific subduction's initiation time.This study uses detrital zircon U-Pb ages to discuss the Late Triassic source-tosink system in the SESCB.It provides some references for the Paleo-Pacific subduction process based on crucial age information and zircons'trace elements.The paleogeography and similarity of detrital zircon age distribution indicate that three sinks were found in the SESCB during the Late Triassic:1.the Yangchun-Kaiping-Gaoming area,comprising major age ranges of 260-220,460-400,and 1200-800 Ma,which might be sourced from the Yunkai terrane;2.the Jiexi-Kanshi-Nanjing area,characterized by the significant age component of 2000-1800 Ma,which corresponded to the Wuyi terrane;3.the Xinan area,consisting of significant age groups of 290-250 and 380-320 Ma,which might be sourced from the magmatic rocks formed by the Huinan Movement and Paleo-Pacific subduction.Note that 290-250 Ma zircons were widely distributed in the Upper Triassic strata,and their trace elements suggested the existence of a magmatic arc near the SESCB during the 290-250 Ma.Thus,we propose that the Paleo-Pacific subduction might have begun in the Early Permian.
