Holocene millennial-scale megaflood events point to ENSO-driven extreme climate changes  

作　　者：Cong CHEN Yanwei ZHENG Zhuo ZHENG Yongqiang ZONG Kangyou HUANG Barry VROLETT Huanhuan PENG Xiao ZHANG Yongjie TANG Qiuchi WAN Guifang ZHANG Rachid CHEDADDI 

机构地区：[1]Guangdong Key Lab of Geodynamics and Geohazards,School of Earth Sciences and Engineering,Sun Yat-sen University,Zhuhai 519082,China [2]Key Laboratory of Separation and Comprehensive Utilization of Rare Metals,Institute of Resources Utilization and Rare Earth Development,Guangdong Academy of Sciences,Guangzhou 510650,China [3]Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082,China [4]Key Lab of Guangdong for Utilization of Remote Sensing and Geographical Information System,Guangdong Open Laboratory of Geospatial Information Technology and Application,Guangzhou Institute of Geography,Guangdong Academy of Sciences,Guangzhou 510070,China [5]Department of Anthropology,University of Hawai’i at Manoa,Honolulu,Hawai’i 96822,USA [6]College of Ocean and Meteorology,Guangdong Ocean University,Zhanjiang 524088,China [7]Institute of Evolutionary Sciences of Montpellier,University of Montpellier,CNRS,Montpellier 34095,France

出　　处：《Science China Earth Sciences》2023年第11期2530-2545,共16页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.42072205&41301582);the National Key R&D Program of China(Grant No.2022YFF0801501);the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.311022010)。

摘　　要：Reconstructing the Holocene megaflood history is a key component of understanding the mechanism of past climate change and assessing the potential impact of future catastrophic events.The Pearl River is the longest watercourse in southern China,and its lower reach has been identified as one of the world's most vulnerable regions for flood exposure.However,there is a complete lack of millennial-scale geological records of paleomegafloods for the future prediction of once-in-a-hundred(even once-in-a-thousand)year floods in southern China.Here,we identified a series of paleomegaflood deposits interbedded with wood-rich peat layers in the lower West Pearl River area.All paleoflood layers have been well dated using AMS~(14)C dating method.According to the regional correlation of the flood sequence,sediment characteristics and provenance analysis,there have been at least 7 megafloods corresponding to once-in-a-thousand-year events in the lower reaches of the West Pearl River during the past 6000 years,with an average return period of approximately 855 years.The identified paleomegafloods were coeval with periods of strong El Ni?o-Southern Oscillation(ENSO),indicating that weakening of the Asian summer monsoon,associated with enhanced ENSO variability,may have triggered abnormally high precipitation leading to flooding of exceptional magnitude in southern China.In addition,the most prominent paleomegafloods identified in the lower Pearl River coincided with intervals of lower precipitation and fewer storms in central-eastern China,indicating the intensification of the meridional“tripole”pattern of precipitation across eastern China during the latter half of the Holocene.Increased land use and deforestation over the last 2000 years have resulted in soil loss and rapid degradation of local primeval forest ecosystems,leading to more catastrophic flooding.Large amounts of rice pollen in the uppermost flood layer during the Song Dynasty indicate that this megaflood may have inundated a large area of cultivated land.The p

关 键 词：Holocene megaflood Asian monsoon ENSO Vegetation change Early farming West Pearl River 

分 类 号：P467[天文地球—大气科学及气象学] TV122.2[水利工程—水文学及水资源]