摘要
地处银川东侧的水洞沟遗址是中国最早发掘的旧石器时代遗址之一,具有丰富的文化内涵,其第1地点不仅出土了具有勒瓦娄哇特点的石器,也发现了新石器时期的文化遗物,表明该地点不只保留单一时代的文化遗存,而是不同时代人类活动的中心。本研究以水洞沟遗址第1地点厚约12.4 m的沉积剖面为主要研究对象,运用光释光(OSL)、^(14)C等多种测年方法建立高精度的年代框架,结合古环境代用指标,揭示古人类生存区域环境的变化,探讨区域气候变化对人类活动的可能影响。新的测年结果显示,该地点在晚更新世时期(约4万年前)被湖泊覆盖,指示了较为湿润的气候特征,这与我国西北地区气候变化特征总体一致。直至28.24±1.89 ka左右湖退,砂黄土在此堆积,由于之后经历了一段时间的侵蚀,因此该剖面的砂黄土层的顶界年龄约为22.72±1.71 ka。古环境代用指标显示,砂黄土平均粒径略大于黄土高原黄土的粒径,粒度分布表现出相似的双峰分布,其主量元素含量与洛川黄土相近,进一步指示了其为风成沉积物,表明水洞沟地区在晚更新世时期经历了相对干旱的环境;自17.11±0.78 ka开始,该地区重新形成湖泊,伴随着气候条件转向湿润,湖泊中也有水生植物生长,使得地层颜色变深,有机质含量增加;尽管全新世地层均为湖相沉积,但是下部沉积物的中值粒径和磁化率均高于上部地层,表明自10665±65 cal.a B.P.起,湖泊水动力由较强转变为微弱,且物源也发生了转变。
The Shuidonggou site(38°17'55.53″N,106°30'06.57″E),located in the east of Yinchuan,is one of the earliest excavated Paleolithic sites in China with rich stone artifacts and fossils.Here we show the results of our new studies about the sediment profile at Locality 1 of the Shuidonggou.This site is positioned on a T2 fluvial terrace north of the Biangou River.Via applying multiple dating techniques,such as optically stimulated luminescence(OSL)and radiocarbon dating(^(14)C),we aimed to establish a high-precision chronological framework for the section.By integrating these dating methods with paleoenvironmental proxies,our study reveals paleo-environmental changes in the study area with implication probably for the entire Northwestern China and explores the impact of climate changes on social development.Locality 1 contains not only Levallois-like blade technology but also Neolithic artifacts,indicating that Shuidonggou witnessed two prehistoric cultures at least rather than being limited to a single period.The stratigraphic profile at Locality 1 has a total thickness of 12.4 m and consists of four sedimentary units from bottom to top.A total of 175 samples were collected for environmental proxy analysis(5-cm intervals in Unit 1 and 4;10-cm intervals in Unit 2;Unit 3 not sampled),9 samples for OSL dating and 7 samples for^(14)C dating.The occurrence of lacustrine sediments at the base of the sequence(Unit 1),along with near-horizontal bedding suggests that the locality was covered by a lake since the Late Pleistocene(ca.40 ka,1 ka=1000 years),suggesting wetter conditions in Northwestern China.After the lake receded(28.24±1.89 ka),sandy loess accumulated(Unit 2).Due to fluvial erosion(Unit 3),the upper boundary of the preserved sandy loess was dated to 22.72±1.71 ka.Paleoenvironmental proxies indicate that the mean grain size of the sandy loess is slightly larger than that of the loess in the Chinese Loess Plateau,and its major element contents are similar to those of the Luochuan loess,further indicating it as aeolian sediments.This suggests that the Shuidonggou region experienced semi-arid conditions during the Late Pleistocene,suitable for loess deposition.The timing of this kind of condition in the Shuidonggou site occurred likely with the formation of aeolian sedimentary records in the western part of the Mu Us Sandy Land.This shows that temperate desert steppe setting was quite beneficial to ancient human habitation.A new lake formed in the region at 17.11±0.78 ka(Unit 4).Although the Holocene strata are all of lacustrine origins,significant differences occur in the paleoenvironmental proxies in the section from different periods.The median grain size and magnetic susceptibility of the lower part are higher than those of the upper strata,indicating that during the formation of the upper lacustrine strata,the hydrodynamic conditions changed from relatively strong to weak,occurring 10665±65 cal.a B.P.Afterwards,the organic content increased,as evidenced by a darker color in the facies.We deduce that during the Holocene Optimum Period,increased summer insolation created a favorable environment for the growth of the aquatic plants at this site.
作者
朱铭卿
杨小平
王旭龙
杜金花
Lydia MACKENZIE
方伊曼
李艾芮
陈波
彭菲
王惠民
郭家龙
高星
ZHU Mingqing;YANG Xiaoping;WANG Xulong;DU Jinhua;Lydia MACKENZIE;FANG Yiman;LI Airui;CHEN Bo;PENG Fei;WANG Huimin;GUO Jialong;GAO Xing(School of Earth Sciences,Zhejiang University,Hangzhou 310058,China;State Key Laboratory of Loess Sciences,Institute of Earth Environment,Chinese Academy of Sciences,Xi'an 710061,China;School of Earth Science and Resources,Chang'an University,Xi'an 710064,China;School of Geography,Planning and Spatial Sciences,University of Tasmania,Hobart 7005,Australia;School of Ethnology and Sociology,Minzu University of China,Beijing 100081,China;Ningxia Institute of Cultural Relics and Archaeology,Yinchuan 750001,China;Key Laboratory of Vertebrate Evolution and Human Origins,Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences,Beijing 100044,China)
出处
《第四纪研究》
北大核心
2025年第5期1220-1238,共19页
Quaternary Sciences
基金
国家自然科学基金项目(批准号:42230502)资助。
关键词
OSL年代学
AMS^(14)C
晚更新世
全新世
环境演变
水洞沟遗址
optically stimulated luminescence(OSL)dating
AMS^(14)C
Late Pleistocene
Holocene
environmental changes
Shuidonggou site
