Anthropic signatures and paleofloods in alluvium of the upper Little Tennessee River valley, southern Blue Ridge Mountains, USA
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This project aimed to compare pre-settlement and post-settlement floodplain sediments and to reconstruct paleoflood history in the upper Little Tennessee River valley, within the Southern Blue Ridge Mountains. The physical and chemical characteristics of overbank sediments at three floodplain sites were studied. Optically stimulated luminescence (OSL), radiocarbon, Cs-137 and historic records provided high-resolution chronology. The sedimentation rates and five elements (Ca, P, K, Pb, Hg) clearly differentiate sediments between the two periods. They were designated as anthropic signatures because their significant differences are largely related to increased human activities during post-settlement time. The paleoflood analysis was based on a modern-analog of flood-sedimentology. Two periods with large floods were identified at A.D. 690-875 and A.D. 1100-1350, corresponding to wet climate conditions. The analysis suggested a wetter MWP and a relatively drier LIA.