Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to ...Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.展开更多
大气氧化是地球宜居性演化的重大事件,深刻影响地球多圈层相互作用。近年来,大气氧化与大陆风化之间的相互作用受到关注。例如,新元古代大气氧化事件可能通过氧化作用,加深风化前锋带,增强风化作用CO_(2)吸收效率,从而引起全球性雪球地...大气氧化是地球宜居性演化的重大事件,深刻影响地球多圈层相互作用。近年来,大气氧化与大陆风化之间的相互作用受到关注。例如,新元古代大气氧化事件可能通过氧化作用,加深风化前锋带,增强风化作用CO_(2)吸收效率,从而引起全球性雪球地球事件(Wei and Li,2024)。这表明风化前锋带推进可能受氧化作用驱动。在氧化作用下,含Fe矿物氧化导致风化壳产生裂隙,裂隙进一步引导质子还原型水解作用,最终推进风化前锋带。根据风化带氧化推进假说,大陆风化与大气氧化理应存在耦合关系,但缺乏深时大陆风化记录予以支撑。展开更多
基金financially supported by the Science and Technology Innovation Foundation of the Command Center of Integrated Natural Resources Survey Center(KC20230002)the China Geological Survey Project(DD20230471,DD20220855 and DD20243282)+1 种基金the National Natural Science Foundation of China(41872100)the National Key R&D Plan(2022YFC2903402)。
文摘Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.
文摘大气氧化是地球宜居性演化的重大事件,深刻影响地球多圈层相互作用。近年来,大气氧化与大陆风化之间的相互作用受到关注。例如,新元古代大气氧化事件可能通过氧化作用,加深风化前锋带,增强风化作用CO_(2)吸收效率,从而引起全球性雪球地球事件(Wei and Li,2024)。这表明风化前锋带推进可能受氧化作用驱动。在氧化作用下,含Fe矿物氧化导致风化壳产生裂隙,裂隙进一步引导质子还原型水解作用,最终推进风化前锋带。根据风化带氧化推进假说,大陆风化与大气氧化理应存在耦合关系,但缺乏深时大陆风化记录予以支撑。
