基于黔西南雾露洞高分辨率石笋同位素记录,重建了62.0～58.2 ka BP和20.9～15.5 ka BP期间亚洲夏季风水文历史和洞穴岩溶环境变化过程。两支石笋(Wu58和Wu60)实测16个^(230)Th年龄和966组氧、碳同位素数据。结果显示,深海氧同位素3阶段(...基于黔西南雾露洞高分辨率石笋同位素记录,重建了62.0～58.2 ka BP和20.9～15.5 ka BP期间亚洲夏季风水文历史和洞穴岩溶环境变化过程。两支石笋(Wu58和Wu60)实测16个^(230)Th年龄和966组氧、碳同位素数据。结果显示,深海氧同位素3阶段(MIS 3)早期和2阶段(MIS 2)期间,千年尺度δ^(18)O变化非常显著,而δ^(13)C则在稳定的背景值下,呈百年尺度波动。去趋势发现,δ^(18)O指示的百年尺度弱季风事件与δ^(13)C指示的土壤CO_2产率衰减过程变化一致。两组同位素变化呈相似的百年尺度波动,共同周期约300 a,说明本区域土壤CO_2产率变化与百年尺度亚洲夏季风变化密切相关。在变化幅度上,δ^(13)C的振幅远大于δ^(18)O(约1.5～3.5倍),表明碳同位素变化对于气候响应具有放大效应,或者δ^(13)C与δ^(18)O变化具有不同的地球化学行为。通过与大气^(14)C、冰芯^(10)Be记录对比,发现百年尺度季风强弱及岩溶过程变化与太阳活动指标具有相似性,说明太阳活动对百年尺度季风强弱和土壤CO_2产率起到主控作用。可能的途径是,太阳活动通过海-陆热力差,影响夏季风强度和当地土壤湿度水平,并经生态效应进一步放大。然而,在百年尺度上,δ^(18)O振幅仅为0.4‰,远小于千年尺度变化(1.5‰)。因此,千年尺度亚洲夏季风突变的诱发因子可能不直接受控于太阳活动,需要其他驱动因素或者气候系统内部放大机制来解释。展开更多
Knowledge of the evolution of pedogenic processes in the carbonate area is important to understand the dynamics of rock desertification.A precisely-dated stalagmite δ13C record between 61.3 and 50.5 ka BP from southw...Knowledge of the evolution of pedogenic processes in the carbonate area is important to understand the dynamics of rock desertification.A precisely-dated stalagmite δ13C record between 61.3 and 50.5 ka BP from southwestern China,potentially related to soil biogenic CO2 production,shifts within a narrow range between -9‰ and -7‰,and exhibits a prominent cycle of 350-470 a,independent of the Asian monsoon changes.This indicates that a threshold effect might control the amplitude of calcite δ13C variability,likely associated with the vertical soil loss in the carbonate area.The periodic δ13C changes reflect that the loss/recovery of soil cover can operate on centennial scale.Thus,the rock desertification in southwestern China might at least initiate 60 ka ago and should be of natural origin.展开更多
Knowledge of the evolution of pedogenic processes in the carbonate area is important to understand the dynamics of rock desertification.A precisely-dated stalagmite δ13C record between 61.3 and 50.5 ka BP from southw...Knowledge of the evolution of pedogenic processes in the carbonate area is important to understand the dynamics of rock desertification.A precisely-dated stalagmite δ13C record between 61.3 and 50.5 ka BP from southwestern China,potentially related to soil biogenic CO2 production,shifts within a narrow range between -9‰ and -7‰,and exhibits a prominent cycle of 350-470 a,independent of the Asian monsoon changes.This indicates that a threshold effect might control the amplitude of calcite δ13C variability,likely associated with the vertical soil loss in the carbonate area.The periodic δ13C changes reflect that the loss/recovery of soil cover can operate on centennial scale.Thus,the rock desertification in southwestern China might at least initiate 60 ka ago and should be of natural origin.展开更多
文摘基于黔西南雾露洞高分辨率石笋同位素记录,重建了62.0～58.2 ka BP和20.9～15.5 ka BP期间亚洲夏季风水文历史和洞穴岩溶环境变化过程。两支石笋(Wu58和Wu60)实测16个^(230)Th年龄和966组氧、碳同位素数据。结果显示,深海氧同位素3阶段(MIS 3)早期和2阶段(MIS 2)期间,千年尺度δ^(18)O变化非常显著,而δ^(13)C则在稳定的背景值下,呈百年尺度波动。去趋势发现,δ^(18)O指示的百年尺度弱季风事件与δ^(13)C指示的土壤CO_2产率衰减过程变化一致。两组同位素变化呈相似的百年尺度波动,共同周期约300 a,说明本区域土壤CO_2产率变化与百年尺度亚洲夏季风变化密切相关。在变化幅度上,δ^(13)C的振幅远大于δ^(18)O(约1.5～3.5倍),表明碳同位素变化对于气候响应具有放大效应,或者δ^(13)C与δ^(18)O变化具有不同的地球化学行为。通过与大气^(14)C、冰芯^(10)Be记录对比,发现百年尺度季风强弱及岩溶过程变化与太阳活动指标具有相似性,说明太阳活动对百年尺度季风强弱和土壤CO_2产率起到主控作用。可能的途径是,太阳活动通过海-陆热力差,影响夏季风强度和当地土壤湿度水平,并经生态效应进一步放大。然而,在百年尺度上,δ^(18)O振幅仅为0.4‰,远小于千年尺度变化(1.5‰)。因此,千年尺度亚洲夏季风突变的诱发因子可能不直接受控于太阳活动,需要其他驱动因素或者气候系统内部放大机制来解释。
基金supported by the National Natural Science Foundation of China(41172148and41130210)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Knowledge of the evolution of pedogenic processes in the carbonate area is important to understand the dynamics of rock desertification.A precisely-dated stalagmite δ13C record between 61.3 and 50.5 ka BP from southwestern China,potentially related to soil biogenic CO2 production,shifts within a narrow range between -9‰ and -7‰,and exhibits a prominent cycle of 350-470 a,independent of the Asian monsoon changes.This indicates that a threshold effect might control the amplitude of calcite δ13C variability,likely associated with the vertical soil loss in the carbonate area.The periodic δ13C changes reflect that the loss/recovery of soil cover can operate on centennial scale.Thus,the rock desertification in southwestern China might at least initiate 60 ka ago and should be of natural origin.
基金supported by the National Natural Science Foundation of China(41172148and41130210)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Knowledge of the evolution of pedogenic processes in the carbonate area is important to understand the dynamics of rock desertification.A precisely-dated stalagmite δ13C record between 61.3 and 50.5 ka BP from southwestern China,potentially related to soil biogenic CO2 production,shifts within a narrow range between -9‰ and -7‰,and exhibits a prominent cycle of 350-470 a,independent of the Asian monsoon changes.This indicates that a threshold effect might control the amplitude of calcite δ13C variability,likely associated with the vertical soil loss in the carbonate area.The periodic δ13C changes reflect that the loss/recovery of soil cover can operate on centennial scale.Thus,the rock desertification in southwestern China might at least initiate 60 ka ago and should be of natural origin.
