129-49 Hydroclimate Variability Relative to Flood Horizons Preserved Along the KY River in Fayette County, Kentucky

Abstract:

Across Kentucky, the frequency and impacts of flood events have become increasingly more concerning. Understanding patterns of Kentucky’s late Quaternary flood events and how they relate to major hydrological changes is key to developing resilience against these changes. Project 2: Paleoperspectives of CLIMBS (Climate Resilience through Multidisciplinary Big Data Learning, Prediction, and Building Response Systems) is focused on developing reconstructions of these changes through the analysis of palynoflora to create a Holocene-based paleoclimate record for Kentucky. Floracliff Nature Preserve, located on the banks of the Kentucky River in extreme southern Fayette County, Kentucky, contains a succession of overbank and point bar deposits preserved at the base of a limestone cliff. Soil and sediment analysis has identified specific flooding horizons, most notably an erosional surface at 1.16 m. Palynological analysis of similar floodplain sediments in eastern Kentucky have been successfully utilized to reconstruct past changes in rainfall regime associated with significant flooding events. Here we present the results of analysis of samples obtained at every 5 cm from an approximately 3-m deep trench through the deposit. These produced a diverse array of pollen, spores, and non-pollen palynomorphs, including fungi. The pollen and plant spore record was used to reconstruct regional conditions present during deposition using CREST in R. The fungal spore record permits highly localized conditions to be assessed. Preliminary data suggests that shifts in precipitation seasonality noted at other sites, especially rapid transitions from warm, summer-wet to warm, summer-dry occur. Here we present updated palynological results and rainfall regime reconstructions.

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