Holocene chronology for lunette dune deposition on the Southern High Plains, USA

Lunettes flank the margins of numerous ephemeral lakes that occur across the Southern High Plains of the United States. While their genesis is closely associated with the hydrology of the adjacent lake systems, the detailed inter-relationships between climate changes and geomorphological and hydrological changes upon the lake-lunette system has been hindered by an absence of reliable age control. In order to develop a chronology of lunette deposition, a luminescence dating programme was undertaken on surface collected and core sections from sets of lunettes which flank the southeast margins of three lake basins near Lubbock, Texas. In contrast to the preconception that the formation of lunettes occurred primarily during the last glacial maximum (18-12 ka), the inner two lunette ridges were observed to be emplaced in a punctuated manner during the middle and late Holocene from 5.6??0.5 to 0.7??0.02 ka. The chronostratigraphy developed in the context of the complex hydrogeological processes associated with the Lubbock lake basins demonstrates that the records of activity preserved within the lunettes provides a useful resolution record of climate change and landscape response.