Younger Dryas事件与北黄海泥炭层的形成  

Younger Dryas Event and formation of peat layers in the northern Yellow Sea

作　　者：李铁刚[1] 常凤鸣[1] 于心科[1] 

机构地区：[1]中国科学院海洋研究所海洋地质与环境重点实验室,山东青岛266071

出　　处：《地学前缘》2010年第1期322-329,共8页Earth Science Frontiers

基　　金：中国科学院知识创新工程项目(KZCX2-YW-221);国家重点基础研究发展计划"973"项目(2007CB815903);我国近海海洋综合调查与评价专项(国家"908"专项)(20062209)

摘　　要：形成于海平面变化处于停滞阶段和湿润气候条件下的泥炭层是古环境变化信息的重要载体。对北黄海4个含泥炭层的沉积剖面进行研究后发现,其均集中在渤海海峡入口处,水深变化在50～54m。泥炭层的AMS14C年龄在10650～1010014 CaBP,与发生在11000～1000014 CaBP间的末次冰消气候回冷事件——Younger Dryas(YD)事件在年代上非常吻合,表明北黄海泥炭层的形成可能与YD事件的全球效应密切相关,可作为YD事件在北黄海陆架响应的一个重要证据。泥炭层在北黄海的集中出现说明,冰后期的海平面上升过程中在YD事件期间存在停滞阶段,这一时期海面已经达到渤海海峡外侧,并可能在此徘徊了近千年。此外,泥炭层的大量出现和孢粉记录表明YD事件发生期间约为10600～1020014 CaBP,此时北黄海可能处在寒冷而湿润的环境。这一发现与全球范围内大部分YD事件的海陆记录存在明显差异,说明不同地区对YD事件的响应存在差异,不能简单地利用单一的干冷模式来分析YD事件在区域上的响应特征和过程。Peat layer,which formed under the humid climatic conditions and during the stagnated phase of sea level changes,is an important vehicle for information of paleoenvironmental evolution. Results of study on four sections of peat layer from the northern Yellow Sea indicate that all of them are located on the mouth of Bohai Sea strait between 50 and 54 meters water depth. The AMS^ 14C ages of peat layer are in the range between 10650 and 10100 a BP,which are highly coincident with the age of the Younger Dryas event that was the most significant cold climatic event during the last deglacial warming and occurred between 11000 and 10000^ 14C a BP. This coincidence indicates that the formation of peat layers in the northern Yellow Sea may be closely correlated with the global impact of Younger Dryas event and can be regard as an evidence of the response of the northern Yellow Sea area to it. The mass appearance of peat layer implies that during the Younger Dryas event a few stagnated periods existed in the post-glacial process of sea level rising,the sea level had reached the outside of Bohai Sea strait and may have lingered for about thousand years. The above results and records of pollen suggest that during the period from 10600 to 10200 ^14C a BP,the northern Yellow Sea was in a cold and humid environment. The humid condition in the northern Yellow Sea area during the Younger Dryas event was distinctly different from the most terrestrial and oceanic records of Younger Dryas event in the global,which shows distinctive effect of Younger Dryas event in different region,and it is irresponsible to diagnose the characteristics of response to Younger Dryas events in different regions based on a single dry and cold mode.

关 键 词：泥炭层 YOUNGER Dryas事件 海平面 北黄海 

分 类 号：P736.22[天文地球—海洋地质]