宁绍平原东部新石器遗址地层碱土金属元素地球化学特征以及对海水入侵事件的指示  

Geochemical characteristics of alkaline earth metals in the sediments of Neolithic sites in the eastern Ningshao Plain and implications for the saltwater intrusion

作　　者：潘昱 孙国平[2] 雷少 吴莹莹[1] 王张华[1] PAN Yu;SUN Guoping;LEI Shao;WU Yingying;WANG Zhanghua(State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China;Zhejiang Cultural Relics and Archaeology Institute,Hangzhou 310014,China;Ningbo Cultural Heritage Management Institute,Ningbo 315012,China)

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200241 [2]浙江省文物考古研究所,杭州310014 [3]宁波市文化遗产管理研究院,宁波315012

出　　处：《海洋地质与第四纪地质》2023年第6期169-180,共12页Marine Geology & Quaternary Geology

基　　金：浙江省重点研发计划“杭州湾沿岸文化遗存与全新世古地貌复原耦合及其三维可视化系统应用”(2022C03141)。

摘　　要：宁绍平原东部地区孕育了丰富灿烂的新石器时代文化,但目前发现的遗址地层中普遍存在着不同时期文化堆积中断现象。选择井头山遗址和鱼山遗址两个剖面进行AMS14C测年、有机地球化学和碱土金属元素分析,探讨稀醋酸提取的碱土金属元素含量变化的特征和原因,同时通过与研究区其他新石器遗址地层记录对比,识别区域性的水文环境变化事件。研究结果显示,稀醋酸提取的碱土金属元素Sr和Ca含量对海岸带低地环境的海水入侵事件十分敏感,是海陆过渡带有效的水文环境代用指标;而Ba含量的变化更加复杂,在两个遗址的中全新世地层中普遍呈现为低值,显示其不仅受水体盐度影响,而且与本地河流输入的泥沙量密切相关。通过区域性地层对比,认为宁绍平原东部新石器时代中晚期存在3次大范围海水入侵事件,分别发生于大约6300、5300和4500 cal.aBP,主要由相对海平面上升或极端风暴事件造成,是新石器遗址文化堆积中断的主要原因。The eastern Ningshao Plain has nurtured rich and splendid Neolithic cultures.However,interruption of the cultural accumulation in different periods has been found in many sites of the study area.To explore the characteristics of variation and mechanism in concentrations of alkaline earth metals extracted with diluted acetic acid(HAc)and to identify regional seawater intrusion events,two Neolithic sites-namely Jingtoushan and Yushan-were chosen for multiple laboratory analyses on AMS14C dating,organic geochemistry,and alkaline earth metals and the profiles were compared with stratigraphic records of other Neolithic sites in the study areas.Results show that the concentrations of alkaline earth metals Sr and Ca in the HAc leachates are sensitive to saltwater intrusion in coastal lowland,which were thus used as effective proxies for revealing the hydrological environment in the land-sea transition zone.However,change in Ba concentration was much more complex and Ba was generally lower in the mid-Holocene sediments,suggesting that Ba concentration was not only influenced by salinity but also by the amount of local riverine supply.In addition,three regional events of saltwater intrusion in the eastern Ningshao Plain at ca.6300,5300,and 4500 cal.aBP in the middle and late Neolithic Age were revealed,and we believe that they were linked to relative sea-level rise or extreme storm events and induced breaks in the accumulation of culture layers.

关 键 词：海岸带低地 Sr BA 水文环境 河流输入 极端风暴事件 

分 类 号：P531[天文地球—古生物学与地层学]