College of Resource and Environment, Northeast Agricultural University, Harbin, 150030, Heilongjiang, China.
Directorate Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium.
Sci Rep. 2022 Nov 28;12(1):20471. doi: 10.1038/s41598-022-24298-z.
Previous palaeoenvironmental reconstructions have implied that East Asia was dominated by a zonal climate pattern during the Eocene, with an almost latitudinal arid/semiarid band at ~ 30° N. However, this long-standing model has recently been challenged by growing body of multidisciplinary evidence. Some studies indicated that central China was characterized by climatic fluctuations between humid and drier conditions during the Early Eocene, akin to the present East Asian monsoon (EAM) regime. Using palynological assemblages in the Tantou Basin, central China, we quantitatively reconstructed climate changes from the Late Palaeocene to Early Eocene to better understand climate change in central China. Palynological assemblages revealed that the coniferous and broad-leaved mixed forest in this area received no less than 800 mm of annual precipitation and experienced a climate change from warm and wet to relatively cool and dry. According to palaeoclimate curves, a sudden climate change occurred in the Early Eocene, with the mean annual temperature and precipitation decreasing by 5.1 °C and 214.8 mm, respectively, and the climate became very similar to the present climate, which is controlled by the monsoon. Therefore, this significant climate change during the Early Eocene may signal the emergence of the EAM in East Asia.
先前的古环境重建表明，在始新世期间，东亚受纬向气候模式控制，在~30°N 附近有一条近乎纬向的干旱/半干旱带。然而，这一长期存在的模式最近受到越来越多多学科证据的挑战。一些研究表明，在始新世早期，中国中部的气候在湿润和干燥条件之间波动，类似于现在的东亚季风（EAM）系统。本研究利用中国中部潭头盆地的孢粉组合，定量重建了晚古新世至始新世的气候变化，以更好地了解中国中部的气候变化。孢粉组合表明，该地区的针叶林和阔叶林混合林每年至少接受 800 毫米的降水，并经历了从温暖湿润到相对凉爽干燥的气候变化。根据古气候曲线，始新世早期发生了一次突然的气候变化，年平均温度和降水量分别下降了 5.1°C 和 214.8 毫米，气候变得与季风控制的现代气候非常相似。因此，始新世早期的这种显著气候变化可能标志着东亚 EAM 的出现。
