Environmental Evolution And Human Activities Of Stratigraphic Rcords In Shangshan Site Area

The Shangshan Site,a representative site of the Shangshan Culture(11? 8.5 ka),is located on the northern bank and the second terrace of the Puyang River,upper reaches of the Qiantang River.It is the earliest Neolithic site ever found in lower reaches of the Yangtze River.The carbonized pottery and carbonized rice remains explored at the Shangshan site reveal the important position of rice farming during the early and middle period of Shangshan Culture,and it is the origin of rice farming in the lower reaches of the Yangtze River,even Eastern China.Recently,many researches have conducted on the Shangshan site,mainly focused on the cultural features of the site,unearthed remains and other research perspective.However,there is currently a lack of a systematic study of the environmental background duration on the evolution of the Shangshan Culture.The grain size,magnetic susceptibility(MS),soil total organic carbon(TOC),palynological and Charcoal analysis were measured in samples taken from the SSYZ section and the ash pit in the exploration area(SSS and SSN).Gramine pollen particle size measurement and palynological analysis and identification of 7 surface samples,combination of the archaeological materials and regional climate background,this paper aims to investigate the variation of sedimentary environment in and around the Shangshan site,and to study the environmental background of humanland relationship evolution history during the early Holocene in Zhejiang Province.The results indicated that: The Shangshan site has experienced three periods since the late Pleistocene(130 ka ? modern):(1)During 130?11 ka BP,(including flood plain(202?142 cm),dust accumulation(142?72 cm)),The dust accumulation was the turning stage of sedimentary evolution in and around the Shangshan site.The material composition mainly composed of silt also laid the parent material foundation for early rice agriculture.The concentration of sporepollen and charcoal increased and then decreased,and the number of terrestrial herbaceous pollen increased,which reflected that the overall climate environment of the region was good,but it experienced great fluctuations and showed a trend of deterioration.The sporopollen assemblage showed that at that time,there was a forest landscape dominated by Pinus,Quercus,etc.under and around the forest,there were herbaceous plants dominated by Gramineae,dandelion and Artemisia,etc.in the later stage The climatic conditions are generally good but deteriorating,which is consistent with the last interglacial-glacial climatic conditions.At the same time,the frequency of regional fire events in this stage decreases gradually(2)From the stage of Shangshan culture to Shangzhou culture,archaeological cultural layer(72?24 cm),the forest vegetation gradually recovered,and the vegetation type was evergreen broad-leaved and deciduous mixed forest.The large-size Gramineae began to appear at the same time.About 10000 years ago through statistics.The proportion of early domesticated rice of Shangshan culture reached about 20% and the proportion of wild rice was 80%,indicating that the rice in the early stage of mountain culture had been domesticated,indicating that human agricultural production activities began in the early stage of mountain culture stage.Combined with the measurement results of environmental proxy indexes such as section grain size,magnetic susceptibility,organic carbon content and archaeological excavation data,since the Holocene,the climate has become warmer,the water and heat conditions have improved,the plant resources are rich,the content of soil organic carbon has increased,and the soil fertility has increased.The geographical location near the river makes it convenient for ancestors to obtain irrigation water sources and stone materials,and finally gave birth to the early rice farming culture of Shangshan culture.At the stage of Kuahuqiao Culture,the intensity of human activities in the mountain site area and its surrounding areas decreased,the forest vegetation recovered,and the vegetation condition was relatively good,which may be related to the good climate conditions or the weak human activities,and the vegetation damage was not serious.Until the late Neolithic cultural stage,the degree of domestication gradually increased to about 28%,but it has not yet reached the modern level of domestication;in the Shang and Zhou cultural stage,the degree of ricedomestication gradually reached the modern level of domestication,and human activities increased.The magnetic susceptibility of SSYZ section increased from the bottom to the top,and the low-frequency and frequency magnetic susceptibility reached their peak of this section in the cultural layer.It was consistent with the variation trend of the magnetic susceptibility in the excavation cultural layer in the ash pit of the exploration area,reflecting the influence of human activities on the MS and the existence of the cultural layer of the Shangshan Culture.(3)Modern farming stage(24?0 cm),the concentration of sporopollen reaches the maximum of the profile,the pollen content of Pinaceae,Taxodiaceae and evergreen oaks and other woody plants increased significantly,and the pollen content of xerophytes such as Artemisia,Taraxacum and Chenopodiaceae decreased.The content of grain and silt is reduced,the sand content is the highest value of the profile and the sorting is very poor,showing a strong influence of human activities such as farming.It reflects that the vegetation type is subtropical evergreen broad-leaved forest and increased farming activities,which is more consistent with the existing vegetation and local agricultural activities.In the topsoil samples,the pollen content of arbor and shrub is more than that of xerophyte and fern spore,the genus Pinus is the highest in arbor shrubs,the content of fern spores is high,and the vegetation is secondary and consistent with the modern climate and vegetation background.