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山西中、东部的榆社、太谷盆地发育了良好的上新世河湖相地层 ,其丰富的植物、鱼类和哺乳类化石为我们提供了一个古植被和古环境研究的理想场所。根据榆社盆地磁性年表以及化石组合特征 ,榆社、太谷盆地约为5 .5 Ma BP以来的一套沉积 ,榆社张村组与太谷小白组的沉积时代相当 ,大约形成于 3.5～ 2 .3Ma BP。从大约 4.4Ma BP开始 ,较高含量的云杉、冷杉花粉显示研究区已有暗针叶林生长 ,从 3.6 Ma BP开始 ,暗针叶林有了较大的发展 ,存在大面积的暗针叶林纯林。大致从上新世中期的 4.4Ma BP开始 ,气候已经开始变冷 ,并有较明显的干湿波动 ,蒿、藜为主的干草原大约从 2 .3Ma BP开始繁盛 ,表明研究区转变为干冷气候
The middle and eastern parts of Yushe and Taigu basins in Shanxi Province have developed favorable Upper Pleistocene fluvial and lacustrine facies, and their rich flora, fish and mammalian fossils provide us an ideal place to study ancient vegetation and paleoenvironment. According to the Yushe basin magnetic chronology and fossil assemblage characteristics, Yushe and Taigu basins have been deposited for about 5.5 Ma BP. The Yushu Zhangcun Formation and Taigu Xiaobu Formation have similar depositional ages, 3.5 ~ 2 .3Ma BP. Starting from about 4.4 Ma BP, the higher content of spruce and fir pollen showed that the dark coniferous forest had been grown in the study area. Starting from 3.6 Ma BP, the dark coniferous forest had a great development with a large area of dark needles Ye Lin pure forest. Starting from 4.4 Ma BP in the mid-Pliocene, the climate began to cool and there was more obvious wet and dry fluctuations. Artemisia and quinoa-dominated steppes began to flourish from about 2.3 Ma BP, indicating that the study area was changed to dry and cold climate