THE RESPONSE OF FLUVIAL SYSTEMS TO CLIMATE CHANGE - AN EXAMPLE FROM THE CENTRAL GREAT-PLAINS

A late Holocene alluvial chronology for a reach of the Republican River, south-central Nebraska, and the late Holocene alluvial and paleoclimatic records of the central Great Plains illustrate the problems inherent in relating fluvial activity to climate change. The alluvial and climatic records reveal that areally synchronous incision around 4200 yr B.P. correlated with a shift to more mesic climatic conditions. Areally synchronous incision after 1100 yr B.P. cannot be correlated to a climate change, primarily because paleoclimatic data for that period are lacking. The dissimilar temporal resolutions of the alluvial and paleoclimatic records hinder attempts to generalize the response of fluvial systems to climate changes. Over relatively long (hundreds of years) and short (tens of years) time scales, the fluvial response to climatic shifts is dependent on variables that may not be discernible in the paleoclimatic record. To enhance understanding of the reaction of fluvial systems to climate change in the Great Plains, additional study of historical fluvial and climate changes should be undertaken, a task complicated by the paucity of fluvial systems that have not been affected by human activity.