Geodynamics of decratonization and related magmatism and mineralization in the North China Craton

The North China Craton(NCC)experienced strong destruction(i.e.,decratonization)during the Mesozoic,which triggered intensive magmatism,tectonism and thermal events and formed large-scale gold and other metal deposits in the eastern part of the craton.However,how the decratonization controls the formation and distribution of large-scale of gold and other metal deposits is not very clear.Based on a large number of published data and new results,this paper systematically summarizes all the data for the rock assemblages,chronology,geochemistry and petrogenesis of Mesozoic magmatic rocks,as well as for the mineralizing ages of gold and other metal deposits and the evolution of the Mesozoic basins in the eastern NCC.The results are used to restore the extensional rates of Mesozoic to Cenozoic basins and the strike-slip distance of the Tanlu Fault,to ascertain the location of the Paleo-Pacific plate subduction zones during the Mesozoic to Cenozoic,and to reconstruct the temporal and spatial distribution of Mesozoic gold and other metal deposits and magmatic rocks in the eastern NCC.It is obtained that the magmatism and mineralization in the eastern NCC westward migrate from east to west during the Early to Middle Jurassic,but they eastward migrate from west to east during the Early Cretaceous.The metallogenesis of these deposits is genetically related to magmatism,and the magmas provided some ore-forming materials and fluids for the generation of metal deposits.The geodynamic mechanism of decratonization and related magmatism and mineralization is proposed,i.e.,the westward low-angle subduction of the Paleo-Pacific slab beneath the NCC formed continental magmatic arc with plenty of porphyry Cu-Mo-Au deposits in the Jurassic,similar to the Andean continental arc in South America.The mantle wedge was metasomatized by the fluids/melts derived from the subducting slab,laying a material foundation for hydrothermal mineralization in the Early Cretaceous.While the rollback of the subducting slab with gradually increasing subduction angle and the retreat of the subduction zones during the Early Cretaceous induced strong destruction of the craton and the formation of extensive magmatic rocks and large-scale gold and other metal deposits.

Porous carbon nanofibers derived from low-softening-point coal pitch towards all-carbon potassium ion hybrid capacitors

Potassium ion hybrid capacitors(PIHC)have promising applications in medium and large-scale energy storage systems due to their high energy/power density,abundant potassium resource and low cost.However,the slow kinetics of battery-type anodes originating from the large-size K+results in a mismatch between the two electrodes,rendering the modest energy density of PIHC.Herein,we first develop an electrospinning strategy to successfully synthesize fibrous precursor by using the HNO_(3)pre-oxidized low-softening-point coal pitch as the low-cost raw material.With further carbonization or KOH activation,the two types of carbon nanofibers(CNF)are fabricated as anode and cathode materials,respectively,towards the dual-carbon PIHC devices.Thanks to its threedimensional interconnected porous conducting network and large layer spacing,the resulted CNF anode material is endowed with high reversible capacities,excellent rate and long cycle stability.Meanwhile,the activated CNF cathode with a large surface area of 2169 m^(2)·g^(-1)exhibits excellent capacitive performance.A PIHC constructed with the two fibrous electrodes delivers an energy density of110.0 Wh·kg^(-1)at 200.0 W kg^(-1),along with a capacitance retention of 83.5%after 10,000 cycles at 1.0 A·g^(-1).The contribution here provides a cost-efficiency avenue and platform for advanced dual-carbon PIHC.