[目的]探讨全新世以来华南地区陆地化学风化强度的变化及其控制因素.[方法]利用琼东海域沉积柱GH7的XRF扫描元素数据,从主量和微量元素中提取代表陆源输入的主成分PC1,分析华南沿海地区化学风化强度.[结果与结论]风化强度在13.2 ka BP以来经历了"强(13.2-7.5 ka BP)—弱(7.5-3.0 ka BP)—强(3.0-0 ka BP)"的变化,并在全球冷事件新仙女木、9.2 ka和8.2 ka时期均有明显减弱.PC1变化显示华南沿海地区风化强度大约在3kaBP处于最强期,反映此时降雨量处于最大期,可能与热带辐合带(ITCZ)在此时期南移至低纬度有关.PC1频谱分析揭示风化强度存在一个约2ka的周期,与厄尔尼诺(ENSO)周期一致,说明华南地区风化强度演变在千年尺度上很可能受ITCZ南移和ENSO的共同调控.
Weathering Evolution in the Southern China during the Holocene Revealed by Element Composition Change in Sediment of Qiongdong Sea Area
[Objective]To investigate the change of chemical weathering intensity and its controlling factors in South China since Holocene.[Method]This study used the data of XRF-scanned elements in the sediment core GH7 from the Qiongdong sea area.The principal component PC1 was extracted from major and trace elements to indicate the intensity of chemical weathering in coastal Southern China.[Result and Conclusion]The weathering intensity showed"strong(13.2-7.5 ka BP)-weak(7.5-3.0 ka BP)-strong(3.0-0 ka BP)"pattern since 13.2 ka BP,and abrupt decrease duringthe Younger Dryas,9.2 ka BP and 8.2 ka BP.The PC1 suggested the weathering in coastal Southern China was strong around 3 ka BP,reflecting the maximum rainfall at this time,which might relate to the Inter-Tropical Convergence Zone(ITCZ)southward shift to low altitudes during this period.The spectral analysis for PC1 revealed a periodic change of about 2 ka in the weathering intensity,close to that of El Niño-Southern Oscillation(ENSO),suggesting that chemical weathering changes at the millennial scale may be regulated together by the ITCZ migration and ENSO intensity.
Holocenesedimentelementsweathering intensityQiongdong sea area
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