We document,for the first time,Mesoproterozoic-aged,continental arc magmatism in the Tasmanides.Granitoid samples intruding the Proterozoic Cape River Metamorphics in northeast Queensland contain abundant∼1200 Ma ign...We document,for the first time,Mesoproterozoic-aged,continental arc magmatism in the Tasmanides.Granitoid samples intruding the Proterozoic Cape River Metamorphics in northeast Queensland contain abundant∼1200 Ma igneous zircons,with early-Paleozoic metamorphic rim overgrowths.Analytical mixing between the igneous and metamorphic zircons produces cryptic discordant analyses,but the origin of said discordance is resolved with zircon Th/U ratios.Samples of the Fat Hen Creek Complex are peraluminous,calc-alkaline,S-type granitoids,that record high-grade metamorphism and trace element mobilization.The P3 and P42 intrusions are metaluminous,calc-alkaline,I-type granodiorite,which intruded the Cape River Metamorphics,and contain trace element signatures consistent with a continental-arc setting.We propose that a Mesoproterozoic continental terrane,herein referred to as the Oakvale Province,exists as basement to the Thomson Orogen.We propose several models for the formation of the Oakvale Province,with potential links to the Tarim Block,and the Yangtze Craton,during the late-Mesoproterozoic.We propose that the Oakvale Province supplied the Tasmanides with late-Mesoproterozoic detritus,and that such detritus was not solely sourced from the Musgrave Province as previously interpreted.Finally,we interpret the oroclinal bending of Paleozoic deformation and plutonic fabrics to reflect the buried extent of the Oakvale Province,and to potentially map out the Neoproterozoic rift margin associated with Rodinia break-up.展开更多
Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic ...Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic setting of the northeastern margin of the North China Craton(NCC).Here,we present U-Pb and Lu-Hf analyses of 712 detrital zircons,and U-Pb analyses of 347 detrital apatites from the Baifangzi,Diaoyutai and Qiaotou formations.The Baifangzi and Diaoyutai formations are dominated by Neoarchean(2.5-2.6 Ga)and Paleoproterozoic(1.8-1.9 Ga)zircons,indicating a predominant NCC provenance.The Qiaotou Formation is dominated by Mesoproterozoic(1.5-1.7 Ga and 1.1-1.3 Ga)zircons with mainly positiveεHf(t)values,which are similar to those from eastern Laurentia,implying a significant provenance transition.The detrital apatite age spectra of the Baifangzi and Diaoyutai Formations show major populations at 1.8-1.9 Ga and 1.1-1.3 Ga.Based on their trace element compositions,the Mesoproterozoic apatites were mainly sourced from metamorphic rocks,indicating regional metamorphism occurred in the NCC during 1.1-1.3 Ga.Combining these data with regional studies,we propose that the NCC was adjacent to eastern Laurentia during the assembly of the Rodinia supercontinent.展开更多
文摘We document,for the first time,Mesoproterozoic-aged,continental arc magmatism in the Tasmanides.Granitoid samples intruding the Proterozoic Cape River Metamorphics in northeast Queensland contain abundant∼1200 Ma igneous zircons,with early-Paleozoic metamorphic rim overgrowths.Analytical mixing between the igneous and metamorphic zircons produces cryptic discordant analyses,but the origin of said discordance is resolved with zircon Th/U ratios.Samples of the Fat Hen Creek Complex are peraluminous,calc-alkaline,S-type granitoids,that record high-grade metamorphism and trace element mobilization.The P3 and P42 intrusions are metaluminous,calc-alkaline,I-type granodiorite,which intruded the Cape River Metamorphics,and contain trace element signatures consistent with a continental-arc setting.We propose that a Mesoproterozoic continental terrane,herein referred to as the Oakvale Province,exists as basement to the Thomson Orogen.We propose several models for the formation of the Oakvale Province,with potential links to the Tarim Block,and the Yangtze Craton,during the late-Mesoproterozoic.We propose that the Oakvale Province supplied the Tasmanides with late-Mesoproterozoic detritus,and that such detritus was not solely sourced from the Musgrave Province as previously interpreted.Finally,we interpret the oroclinal bending of Paleozoic deformation and plutonic fabrics to reflect the buried extent of the Oakvale Province,and to potentially map out the Neoproterozoic rift margin associated with Rodinia break-up.
基金financially supported by the National Natural Science Foundation of China(Grant No.41902224,41602209).
文摘Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic setting of the northeastern margin of the North China Craton(NCC).Here,we present U-Pb and Lu-Hf analyses of 712 detrital zircons,and U-Pb analyses of 347 detrital apatites from the Baifangzi,Diaoyutai and Qiaotou formations.The Baifangzi and Diaoyutai formations are dominated by Neoarchean(2.5-2.6 Ga)and Paleoproterozoic(1.8-1.9 Ga)zircons,indicating a predominant NCC provenance.The Qiaotou Formation is dominated by Mesoproterozoic(1.5-1.7 Ga and 1.1-1.3 Ga)zircons with mainly positiveεHf(t)values,which are similar to those from eastern Laurentia,implying a significant provenance transition.The detrital apatite age spectra of the Baifangzi and Diaoyutai Formations show major populations at 1.8-1.9 Ga and 1.1-1.3 Ga.Based on their trace element compositions,the Mesoproterozoic apatites were mainly sourced from metamorphic rocks,indicating regional metamorphism occurred in the NCC during 1.1-1.3 Ga.Combining these data with regional studies,we propose that the NCC was adjacent to eastern Laurentia during the assembly of the Rodinia supercontinent.
