Mid- to- late Holocene hydroclimatic changes on the Chinese Loess Plateau: evidence from n-alkanes from the sediments of Tianchi Lake
Mid- to- late Holocene hydroclimatic changes on the Chinese Loess Plateau: evidence from n-alkanes from the sediments of Tianchi Lake
复制标题
中国黄土高原全新世中晚期水文气候变化——来自天池沉积物正构烷烃的证据
DOI：
10.1007/s10933-018-0037-9
复制
发表时间：
2018
影响因子：
2.1
通讯作者：
Zhou Aifeng
中科院分区：
文献类型：
--
作者：
Sun Huiling;Bendle James;Seki Osamu;Zhou Aifeng
利用天池沉积物正构烷烃数据重建了黄土高原全新世中晚期的古水文变化历史。我们使用Paq（水生植物占总植物群落的比例）来反映湖泊水位的变化，沉水植物的丰度越高，水位越低，反之亦然。基于Paq的水文重建结果与天池沉积物的平均碳链长度（ACL）、碳偏好指数（CPI）、C/N比和烷烃分子分布等数据吻合较好。结果表明，在5.7- 3.2kaBP期间，湖泊水位相对较高，之后逐渐下降。我们的古水文重建与现有的古气候重建黄土高原，这表明一个潮湿的中全新世，但与中国中部的古气候记录，这表明干旱的中全新世是异步的。总体而言，我们的研究结果证实，由东亚夏季风（EASM）提供的降雨强度是一个重要的因素，在影响该地区的古水文变化，可以被认为是一个空间上异步的发展“北方中国干旱和中国南方洪水”的降水模式在全新世的进一步证据。
We have reconstructed the history of mid-late Holocene paleohydrological changes in the Chinese Loess Plateau usingn-alkane data from a sediment core in Tianchi Lake. We used Paq(the proportion of aquatic macrophytes to the total plant community) to reflect changes in lake water level, with a higher abundance of submerged macrophytes indicating a lower water level and vice versa. The Paq-based hydrological reconstruction agrees with various other lines of evidence, including ACL (average chain length), CPI (carbon preference index), C/N ratio and then-alkane molecular distribution of the sediments in Tianchi Lake. The results reveal that the lake water level was relatively high during 5.7–3.2 ka BP, and decreased gradually thereafter. Our paleohydrological reconstruction is consistent with existing paleoclimate reconstructions from the Loess Plateau, which suggest a humid mid-Holocene, but is asynchronous with paleoclimatic records from central China which indicate an arid mid-Holocene. Overall, our results confirm that the intensity of the rainfall delivered by the EASM (East Asian summer monsoon) is an important factor in affecting paleohydrological changes in the region and can be considered as further evidence for the development of a spatially asynchronous “northern China drought and southern China flood” precipitation pattern during the Holocene.