ENVIRONMENT EVOLUTION AND HUMAN ACTIVITIES SINCE MIS 3 AT DAYINDONG SITE,YUNNAN
The Dayindong site(24° 13′34.90″N,105°02′ 15.41″E)is recognized as the largest prehistoric cave cemetery ever found in Yunnan,Southwest China.It is a Triassic limestone cave comprised of two chambers(Area Ⅰ and AreaⅡ),totaling approximately 1500 square meters.Positioned in front of the cave is a steeply sloped area,while the interior terrain remains relatively flat.The front chamber(Area Ⅰ)is connected to the cave mouth by a sloping pathway with a descent of around 10 meters.Excavations covering an area of 300 square meters have yielded a rich assemblage of artifacts associated with human activities,primarily dating from the late Neolithic to the Bronze Age.Exploring the ecological evolution and human activities at the Dayindong site since the Late Pleistocene is crucial for understanding ancient human activities and their environmental adaptations in Southwest China.The studied profile(T1-NE)extends to a depth of 269 meters,and samples including charcoals,snail shells were collected from pivotal strata for AMS 14C analysis.Additionally,89 samples were obtained at 3 cm intervals along the profile for particle size,pollen,and charcoal concentration analyses.This multi-proxy analysis reveals the environmental background spanning from the MIS 3 period to the Late Holocene(approximately from＞45473 cal.aB.P.to 851± 71 cal.aB.P.).We reconstruct the sedimentary evolution of the strata by applying sedimentology principles and conducting particle size analysis.Furthermore,it offers an explanation to the phenomenon of stratigraphic age reversal,and illuminating the process by which the initial sediments were transported and redeposited by laminar flow.On this basis,pollen and charcoal were used to analyze the ecological environment and human activities.The results show that the sediments of the T1-NE profile include:(1)sediments deposited by water flowing down the nearby slope;(2)remnants of human activities,including ash layers and cultural artifacts;and(3)limestone breccia formed during the karstification process of the cave.Within the depth range of 38 cm to 0 cm lies sediment dating from the Late Neolithic to the historical period.This layer,primarily composed of remnants from human activities,was unaffected by rainwater and surface runoff at the cave entrance.From 269 cm to 38 cm,the sediment exhibits a series of parallel beddings with depositional hiatuses.Analysis of particle size reveals three discernible sedimentary processes,likely resulting from sporadic heavy rainfall since the Last Glaciation.These occurrences led to temporary surface runoff,which transported sediments from the cave entrance to the inner cave platform where they were regularly redeposited.Based on the sedimentological and chronological framework,the analysis of pollen and charcoal offers pivotal insights into the ecological environment,climate variations,and early human activities since MIS 3.The study area showed a pronounced abundance of forest vegetation resources.Human habitation in this area can be dated back to at least 40000 years.In MIS 3,the dynamics of vegetation underwent notable transformations.Initially,the landscape was predominantly characterized by deciduous trees and shrub.Subsequently,a transition ensued towards a blend of coniferous and deciduous broad-leaved forests in the middle phase.Ultimately,in the later stage saw the prevalence of tropical to subtropical evergreen broad-leaved forests.The local climate during this period also underwent a transition from cool and humid to cold,and then to warm and humid.Additionally,the intensity of human activities varied from weak to strong,indicating that the caves,along with their surrounding ecological environment,provided favorable living conditions and ample food resources for ancient humans.During the Last Deglaciation and Early Holocene,the prevailing vegetation comprised of deciduous broad-leaved forests.The climate was relatively mild and dry.Meanwhile,there was a decrease in human activities.This decrease can be attributed to the expansion of human settlements and the gradual interaction and communication with neighboring cultures.In the Late Holocene,the forest vegetation was dominated by deciduous broad-leaved trees and shrubs,while the climate was cool and dry.Nevertheless,early human societies initiated the cultivation of rice,meaning the transformation of their lifestyle and adaptive approach.This study serves as a reference for conducting in-depth research on the ecological environment,climate change,and their impact on early human activities in Southwest China since MIS 3.
国家自然科学基金重大项目国家自然科学基金联合基金项目国家重点研发计划项目中国科学院战略性先导科技专项项目(B类)科技部第二次青藏高原综合考察研究项目云南省科技领军人才项目云南省基础研究计划项目重点项目兴滇英才支持计划项目Queensland-Chinese Academy of Sciences Collaborative Science Fund
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