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通过对位于非季风区的柴达木盆地、过渡区的临夏盆地两个早更新世典型湖相沉积剖面孢粉记录的研究,揭示出早更新世柴达木盆地地带性植被整体以疏林草原/草原为主,临夏盆地早期为柏疏林草原后演变为针叶林/针叶林草原而后又演变为疏林草原;已有的季风区黄土高原孢粉资料表明三门古湖早期为疏林草原后演变为松林/针阔混交林,泥河湾古湖为针叶林后演变为亚热带常绿阔叶林,表明早更新世时自西向东湿润程度增加,并且各地气候都较现在湿润,暗示着当时存在较强的东亚夏季风.
Based on the records of two early Pleistocene lacustrine sedimentary sections in the non-monsoon Qaidam basin and the Linxia basin in the transitional region, it is revealed that the zonal vegetation of the Qaidam basin in the early Pleistocene is dominated by the sparse forest steppe / Grassland, the Linxia basin later transformed into coniferous forest / coniferous forest grassland in the early stage of Possum forest steppe and then to sparse forest steppe; the existing monsoon loess plateau pollen data show that the early Sanmen ancient lake was sparse The forest grassland evolved into a pine forest / coniferous and broad-leaved mixed forest, and the ancient river Nihe became the coniferous evergreen broad-leaved forest, indicating that the early Pleistocene moisturization increased from west to east, and the climate is wetter than the present , Suggesting that there was a strong East Asian summer monsoon.