青藏高原东部边缘“成都黏土”粒度记录的约500kaBP的干旱化增强事件

DRYING EVENT AT 500 kaBP RECORDED BY THE CHENGDU CLAY GRAIN SIZE AT THE EASTERN MARGIN OF THE TIBETAN PLATEAU

亚洲内陆干旱化是新生代青藏高原隆升和全球气候恶化的重要标志。对位于青藏高原东部边缘的成都黏土粒度记录的研究,及与黄土高原地区粒度记录的对比,表明该地区的粒度记录都在约500kaBP时发生了一次明显的粒度增大、粗颗粒含量增加的变化,表明东亚地区约500kaBP以来发生了一次明显的干旱化增强事件,推测青藏高原在中更新世强烈隆升进入冰冻圈,导致中下层西风环流显著分叉绕流以及随后的进一步强化,是亚洲内陆干旱化阶段性增强的重要原因。

Asian aridification is a reflection of the combination of the uplift of the Tibetan Plateau and global cooling. Comparison of the grain size of the Chengdu Clay from the eastern edge of the Tibetan Plateau and that of the Chinese Loess Plateau reveals a significant arid intensification event at about 500 ka. We estimate that the rapid uplift of the Tibetan Plateau during the middle Pleistocene and its entering cryosphere have caused this event.