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在野外考察采样基础上,结合OSL和ESR测年确定红土沉积年代,对福建长乐(CL)红土剖面微量元素地球化学特征及指示的古环境意义进行了初步研究。结果表明:CL剖面中微量元素的含量和分布特征呈有规律的波动变化,反映出区域风化成壤过程中不同元素的地球化学行为存在差异。较高的Mn、Nb、Rb、Cr含量或较低的Ni、As、Sr、Zn、V含量大体指示红土沉积风化作用增强,气候暖湿;反之,则可能指示生物化学风化作用减弱,气候温干或凉干。早更新世晚期以来,研究区古气候经历了温干-暖湿,暖湿,暖湿-干冷,温干-暖湿,暖湿的变化过程。研究揭示出CL剖面微量元素记录的区域气候变化过程既是对全球气候变化的响应,同时也表现出亚热带季风区红土沉积风化的特殊性。
Based on field investigation and sampling, combined with the dating of OSL and ESR to determine the age of laterite deposition, the trace element geochemical characteristics and paleoenvironmental significance of the red clay profile of Changle (CL) in Fujian Province were studied. The results show that the content and distribution of trace elements in CL profile fluctuate regularly, reflecting the differences in geochemical behavior of different elements during the process of regional weathering and pedogenesis. The higher contents of Mn, Nb, Rb and Cr or lower contents of Ni, As, Sr, Zn and V generally indicate that weathering of lateritic sediments is enhanced and the climate is warm and humid. On the contrary, the biochemical weathering may be weakened, Dry or dry. Since the late Early Pleistocene, the paleoclimate in the study area experienced the process of warm-dry, warm-wet, warm-wet-dry-cold, warm-dry- warm-wet, warm-wet. The study reveals that the regional climate change recorded by CL trace elements is not only a response to global climate change but also shows the particularity of lateritic weathering in the subtropical monsoon region.