Aeolian and Pedogenic Processes of Loess in Southern England

Abstract: Loess is an aeolian sediment that can be utilized as a detailed proxy of past climate, since it is one of few sediments that is deposited directly from the atmosphere on land. Investigation of loess deposits can give understanding of past regional and local wind circulation patterns and velocities, atmospheric dustiness, as well as paleo-precipitation and weathering conditions. The aim of this dissertation was to determine the aeolian sediment transport processes, wind circulation patterns, and weathering conditions, that existed during the deposition of the Pegwell Bay loess in south-east England. This was done by the means of grain size distribution and magnetic susceptibility analysis of 34 samples from the Pegwell Bay loess sequence. The result of the analysis strongly suggests the section contains pure loess without interruptions of paleosols and was deposited during the end of the last glacial. The data indicates that the lower part of the unit accumulated relatively rapid during a rather stable cold and dry phase, with events of enhanced regional winds and activations of local sandy sources. It also shows an increase of weathering in the upper unit compared to the lower, which implies milder climate and an increase in paleo-precipitation and temperature either in early Holocene, or at the end of the last glacial. The uppermost part of the upper unit also shows signs of multiple sources, which could be a sign of the activation of more local sources. The results of this study allowed the first constraint of climate change and wind patterns from loess in this region.