THE RELATIONSHIP BETWEEN HUMAN ACTIVITIES,CLIMATE AND VEGETATION IN YOUFANG SITE DURING MIS 5,NIHEWAN BASIN
The Youfang site,a significant middle to upper Paleolithic site in the Nihewan Basin,has yielded lithic assemblages including flake tool industry in North China and microblade industry.These findings provide new insights into the transition from flake tool industry to microblade industry in North China.The YFTG2 section of the Youfang site(40°13′52″N,114°41′02″E;921 m a.s.1.)represents a typical stratum of the middle Paleolithic in the Nihewan Basin,dated between 100.6±5.7 ka and 52.3±2.5 ka(0～535 cm in depth),corresponding to the warming period of Marine Isotope Stage(MIS)5 and the early warm period of MIS 3,providing valuable materials for studying relationship between Paleolithic cultural evolution and climate change in the region.A total of 54 samples were obtained at 10 cm intervals.The climate background of human activities in the Nihewan Basin during the middle Paleolithic period was reconstructed based on the pollen,grain size and loss on ignition(LOI).The results show that:(1)MIS 5d(535～255 cm,100.6±5.7～92.1±2.9ka),pollen assemblage were dominated by herbaceous taxa(88.9％),with Chenopodiaceae(37.1％),Artemisia(23.2％)and Poaceae(9.4％)being prominent.At depths of 535～255 cm(100.6±5.7～92.1±2.9 ka),median grain size was 10.2～93.4 μm,organic matter content was 2.2％～4.4％,and calcium carbonate content was 1.7％～5.0％.This stage was characterized by a cold and dry climate.MIS 5c(255～180 cm,92.1±2.9～89.8±3.5 ka),the pollen assemblages showed a significant increase in tree and shrub pollen(82.0％),dominated by Pinus(47.5％),Betula(15.8％),Carpinus(11.6％)and Quercus(2.1％).Median grain size was 19.4 μm,and calcium carbonate content decreased obviously to 1.9％.The climate during the period was warm and humid.MIS5b(180～130cm,89.8±3.5～87.7±4.4 ka):Pollen composition was dominated by tree and shrub taxa(75.8％),with a decrease in Pinus(36.0％)and Carpinus(4.2％),and an increase in Quercus(4.5％)and Betula(21.4％).Artemisia content increased to 13.6％.Median grain size remained relatively stable.Organic matter content significantly increased to 5.0％,while calcium carbonate content decreased to 0.2％.The climate of MIS 5b was relatively cool and wet in the Nihewan Basin.Early MIS 3(130～0 cm,55.7±3.5～52.3±2.5 ka):Pollen assemblages indicated a decrease in tree and shrub pollen(68.2％),with an increase in Pinus(39.3％),Artemisia(15.6％),and Chenopodiaceae(5.3％).Median grain size increased to 39.0 μm.Organic matter content slightly decreased to 4.5％,while calcium carbonate content increased to 1％.The climate transitioned to warm and wet conditions during this period.(2)The results of vegetation quantitative reconstruction show that,during the MIS5d,the herbaceous coverage in Nihewan Basin is 78.1％,and formed a sparsely wooded and grassland landscape dominated by Poaceae(37.8％),Chenopodiaceae(16.2％)and Quercus(6.1％).During MIS5c,the Nihewan Basin was characterized by a pine-dominated theropencedrymion with Pinus(46.2％),Carpinus(21.6％),Betula(9.1％),Rosaceae(8.1％)and Poaceae(4.7％).During MIS 5b,the landscape of the Nihewan Basin was still dominated by the theropencedrymion with Pinus(42.8％),Betula(12.8％),Quercus(8.1％),Rosaceae(12.5％),Poaceae(5.8％)and Artemisia(4.4％).During the early MIS 3,landscape of Nihewan Basin is theropencedrymion mainly composed of Pinus(41.8％),Carpinus(22.1％),Quercus(7.3％),Poaceae(7.3％)and Rosaceae(6.0％).(3)Stone artefacts were unearthed throughout YFTG2,indicating that hominins had strong adaptability to the natural environment with alternating dry and wet in MIS 5d～MIS 5b and early MIS 3.Abundant precipitation brought by the strengthened East Asian monsoon was conducive to the formation of the mixed forest.The suitable climate of Nihewan Basin and forest grassland and coniferous broad-leaved mixed forest provided an ideal place for human activities during this period.In MIS 5b,human activities in the area weaken due to the wet climate and increase water volume.
MIS 5early MIS 3pollenclimate and vegetationYoufang site in Nihewan Basin
万方数据
维普
