The Relationship Between Paleoenvironment/Ancient Flood And And Cultural Spatial Distribution In The Yi/Shu River Basin During The Holocene

The research on climate change,regional cultural evolution and man land relationship has always been one of the hot topics at home and abroad.As the main body of Haidai civilization,Shandong has a relatively complete and continuous cultural sequence;the regional geomorphic environment is relatively stable,and it is located on the low steps of China's geomorphic trend,which is a very stable denudation area since the lower Paleozoic era.The accumulation of sites is mainly in the form of superposition,and the archaeological culture rarely changes in space.This makes the study of climate environment evolution and man land relationship in this warm temperate monsoon climate region attracted much attention,and it has special significance for enriching the content and theory of man-land relationship.This study conducted a general survey of the landform characteristics of the Yi/Shu River Basin,and selected the Chuanliu Street(CLJ-2)profile located on the first terrace(the top is 3.8-4.0 meters above the modern riverbed),and systematically sampled and analyzed The granularity characteristics of the profile,the washing of carbon particles,and the AMS-14 C dating were carried out to establish the chronological sequence of the profile,thereby identifying the flood events and flood records since the last glacial maximum in the basin;combined with existing research profiles,The conditions of the Holocene paleohydrological environment and the characteristics of climate and environmental changes in the basin are described.The study further counted the geographical and geomorphological information of 5936 cultural sites in the basin.Based on the Arc GIS10.5 platform,the temporal and spatial distribution characteristics of cultural sites in various periods were analyzed,and combined with existing climate and environmental records,the Yi/Shu River Basin was discussed.The relationship between regional cultural evolution and paleo-climate changes,paleo-flood records.The preliminary study concluded that:(1)The Yi/Shu River is located in the transition zone from the mountainous landform in Southeast Shandong to the Huang huaihai Plain.The bedrock bed intermittently exposed along the river forms the erosion base level of the local river section of the river;the river erosion is limited;the last time The first-level terraces formed since the glacial period(18-21 ka BP)have developed slowly and steadily,and the terraced ground is relatively broad and flat;the terraces have the attributes of up-stacking and in-stacking,and the thickness of the terraces is small,generally no more than 3-5m.The modern river bed is only about 3m;the river is a braided river.The Yi/Shuhe first-level terrace is the main geographical and geomorphic unit where humans are densely populated in the Neolithic and historical periods;the analysis of riverside degree reveals that no matter in the Neolithic or Paleolithic,within 7km from the river are most of the sites in the basin(65 % Above)the distribution of geographic and geomorphic space.This aspect makes it easy for humans to obtain surface water and groundwater resources,and at the same time increases the risk of river flooding,which poses a severe challenge to the survival of ancient humans in the region.(2)The Clj-2 profile reveals that during the last deglacial period 15.0-9.2 ka BP,there were 10 abnormal flood records with relatively long duration and thick deposits;in the profile,the thickness of the flood marks reached 1.0-2.4 cm,but the grain size Indicator records show that the river flood water environment is relatively stable.During the period of 9.2-3.2 ka BP,there were more than 10 abnormal floods in the basin.The grain size records showed that the hydrological environment of the flood was unstable;since 3.2 ka BP,the Clj-2 profile has entered the high floodplain stage,and the water environment recorded by the grain size index is relatively stable.(3)Environmental topographical factors such as elevation,water system,slope,aspect and riverside degree all have a certain influence on the spatial distribution of ancient settlements.Ancient cultural sites in the Yi/Shu River Basin tend to be distributed in geographical and geomorphic environments with an altitude of 0-350 m,a low slope(?3°),and a sunny slope(slope direction 90°-270°);the distance area is1-3 levels Within 5km of the river,this basically corresponds to the geomorphological space of the river's first terrace.These areas can fully and conveniently use water resources.However,it is obvious that the unstable water environment during the period of 9.2-3.2 ka BP has a significant impact on the survival of ancient humans living on the first terrace,but it has not yet come from The empirical record of archaeological excavation is a content,that needs to be paid attention to in the future Holocene human-land relationship in the basin.