中国东部陆架海对“新仙女木”事件的响应

THE RESPONSE OF THE CONTINENTAL SHELF SEAS IN EASTERN CHINA TO THE "YOUNGER DRYAS" EVENT

新仙女木(Younger Dryas)事件是末次冰消期持续升温过程中的一次突然降温的典型非轨道事件,对于研究古气候、古环境的快速突变事件和短周期现象,合理评估现今气候—环境条件并做出气候变化的预测有着重要的意义。它是一个全球性的事件,中国东部陆架海也普遍发现了“新仙女木”事件的沉积记录。由于中国东部陆架位于欧亚大陆和太平洋之间,受季风的强烈影响,因此有着独特的响应。在“新仙女木”事件发生时,海平面在-50 m水深位置稍微下降或振荡徘徊,在-50 m线上则以湖泊沼泽、埋藏河床、风沙沉积记录为主,-50 m以下则以海洋沉积记录为主,这条线的附近则存在沼泽泥炭和古潮流沙脊。

Younger Dryas event was a typical and abrupt nonorbital cold event during the last deglaciation when it was continuing to be warm and a global event. The sediment records were found in the East China Sea shelf. The East China Sea shelf had its own characters because it was situated between Eurasia and the Pacific and was affected by monsoon. When the cooling event happened, the sea level fell or oscillated at about?0 m deep, so the relatively high energy and predominant sediment records were divided around the?0 m line: above the line, the records showed lakes, morass, embedding riverbeds and sand blow by wind; and below the line, the sediment records were of oceanic characteristics. Near the line there were swamp turfs and paleo-tide sand ridges. Further study is needed to understand how the Younger Dryas event had a strong impact on palaeoenvironment and palaeogeography in the shelf sea in eastern China.