PaleohydrologicalVariationsince13kaBPinMiddleYangtzeRegion

MiddleYangtzeinSouthChinaiswellknownbythefrequentoccurrenceoffloodinginassociationwithdrought events.However,lessisknownaboutthehydrologicalvariationintheancienttimes.Hereweareabletoreconstructthepaleohydrologicalconditionssince13kaBPinthisregionbasedonthesynthesisof4proxiesextractedfromtheDa jiuhupeatlandand stalagmiteinHeshangcavenearQingjiangRiver.Threelong-termdrierperiods(11.7-10.7kaBP,6.4-5.5kaBPand4.0- 3.0kaBP)andthreelong-termhumid/floodingperiods(13.0-11.7kaBP,8.7-6.4kaBP,3.0-1.7kaBP),eachlastingover onethousandyears,wereidentifiedinthistimeinterval.Thehumidperiodat8.7-6.4kaBP(knownasHoloceneOptimum) isofabroadregionoronaglobalscale,whenthesedentaryvillage-basedricecultivationwasdeveloped.Thesubsequentdrier periodsat6.4-5.5kaBPisalsoofabroadregionorevenofglobalscalewhenthecomplicatestate-levelsocietystructurewas established.Thelong-lastingdrierperiodscouldbepresentedpriortoorpostthelong-lastinghumidperiods.Inaddition,5 short-termdroughtevents(9.8-9.2kaBP,9.0-8.7kaBP,5.0-4.2kaBP,1.7-1.1kaBP,0.7-0.0kaBP)and5shorttermhumidperiods( 10.7-9.8kaBP,9.2-9.0kaBP,5.5-5.0kaBP,4.2-4.0kaBP,1.1-0.7kaBP)werealsoidentified. InmiddleYangtzeregion,mostdrierperiodsoccurredatthewarmconditions,differentfromthecold-droughtassociationin NorthChina.Meanwhile,thehumidclimatecouldoccuratboththecoldandwarmconditions,indicatingthecomplicaterelationshipbetweentemperatureandhumidity.Itisnotablethatthearidityincreaseswhenthetemperatureshiftsfromonestateto another(i.e.,fromcoldtowarmorfromwarmtocoldconditions)inMiddleYangtze.Hydrologicalconditionsalsoplayanimportantimpactonhistoricalculturesinthisregion