Diatom-based inference of Asian monsoon precipitation from a volcanic lake in southwest China for the last 18.5 ka
Diatom-based inference of Asian monsoon precipitation from a volcanic lake in southwest China for the last 18.5 ka
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基于硅藻的西南火山湖近18.5ka亚洲季风降水推断
DOI：
10.1016/j.quascirev.2017.11.021
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发表时间：
2018
影响因子：
4
通讯作者：
Zhang Enlou
中科院分区：
文献类型：
--
作者：
Li Yanling;Chen Xu;Xiao Xiayun;Zhang Hucai;Xue Bin;Shen Ji;Zhang Enlou
火山湖中的硅藻提供了pH值变化的替代证据，其特征在于嗜酸硅藻物种的百分比变化。根据以前的出版物和对该湖一年的调查得出的关于该湖水文的资料表明，pH值在雨季较低，在旱季较高。因此，湖水pH值的变化可以被认为是过去降水变化的替代记录。在沉积物中，高/低相对丰度的嗜酸硅藻物种表示高/低的降水。18.5kaBP以来的硅藻记录表明，在17.0-15.0，13.3-11.3，0.7- 0.3kaBP期间，降水量减少，分别对应于Heinrich事件1（H1）、新仙女木冷事件（YD）和小冰期（LA）。15.0 ~ 14.5 ka BP之间的降水量显著增加发生在H1末期和Bølling-Allerød（BA）之前，这表明Bølling之前有一个强的湿润过程。全新世开始于11.3kaBP。11.3 ~ 7.5kaBP是气候最湿润的时期，7.5 ~ 3.4kaBP为湿润期。3.4 ~ 0.7kaBP降水总体减少，1.3 ~ 0.8kaBP降水偏多，对应中世纪暖期。我们的研究结果支持了印度夏季风（ISM）在全新世早期最强的假设。
Diatom in the volcanic lake provides proxy evidence for pH changes that are characterized by variations in the percentage of acidophilous diatom species. The information regarding the hydrology of the lake, derived from a previous publication and survey of one year on the lake, indicate that pH is low during the wet season and higher during the dry season. Therefore, variations in lake water pH may be considered as a proxy record for past changes in precipitation. In the sediment, high/low relative abundance of acidophilous diatom species indicates high/low precipitation. The diatom record of the past 18.5 ka BP shows that precipitation decrease during the periods 17.0–15.0, 13.3–11.3, and 0.7–0.3 ka BP corresponding to the Heinrich Event 1 (H1), the Younger Dryas cold event (YD), and the Little Ice Age (LA). A marked precipitation increase between 15.0 and 14.5 ka BP occurred at the end of H1 and before the Bølling-Allerød (BA), which indicates a strong pre-Bølling wetting. The start of the Holocene is recorded at 11.3 ka BP. The climate was the wettest between 11.3 and 7.5 ka BP., then the wetter between 7.5 and 3.4 ka BP. Between 3.4 and 0.7 ka BP, the precipitation decrease in general, but in the period from 1.3 to 0.8 ka BP the precipitation was higher corresponding to the Medieval Warm Period (MWP). Our results support the hypothes that the Indian Summer Monsoon (ISM) was strongest during the Early Holocene.