East African lake evidence for Pliocene millennial-scale climate variability
East African lake evidence for Pliocene millennial-scale climate variability
复制标题
上新世千年尺度气候变化的东非湖泊证据
作者：
K. Wilson;M. Maslin;M. Leng;J. Kingston;A. Deino;R. K. Edgar;A. Mackay
非洲新生代晚期的气候历史不时出现变化，其特点是东非大裂谷内大型淡水湖的出现和消失。在 Baringo-Bogoria 盆地，一系列已确定年代的硅藻土和河湖沉积物记录了 2.70 Ma 至 2.55 Ma 之间广泛湖泊系统的进动强迫循环。对一个硅藻土单元进行了研究，利用硅藻二氧化硅的氧同位素组成，结合X射线荧光光谱测定和分类组合变化，探索该时期气候变化的本质。数据显示，深水湖泊状况迅速发生并逐渐衰退，表现出约 1400-1700 年的千年尺度周期性，类似于第四纪晚期 Dansgaard-Oeschger 事件。这些周期被认为反映了降水量的增加与季风强度的增加同时发生，表明这一时期高纬度地区和东非之间存在遥相关。这种气候变化可能影响了当时动物和花卉的进化。
Late Cenozoic climate history in Africa was punctuated by episodes of variability, characterized by the appearance and disappearance of large freshwater lakes within the East African Rift Valley. In the Baringo-Bogoria basin, a well-dated sequence of diatomites and fluviolacustrine sediments documents the precessionally forced cycling of an extensive lake system between 2.70 Ma and 2.55 Ma. One diatomite unit was studied, using the oxygen isotope composition of diatom silica combined with X-ray fluorescence spectrometry and taxonomic assemblage changes, to explore the nature of climate variability during this interval. Data reveal a rapid onset and gradual decline of deepwater lake conditions, which exhibit millennial-scale cyclicity of ∼1400–1700 yr, similar to late Quaternary Dansgaard-Oeschger events. These cycles are thought to reflect enhanced precipitation coincident with increased monsoonal strength, suggesting the existence of a teleconnection between the high latitudes and East Africa during this period. Such climatic variability could have affected faunal and floral evolution at the time.
影响因子：
4
作者：
Trauth;Maslin;Junginger;Strecker;Tiedemann
通讯作者：
Tiedemann