Colluvial deposits in dry valleys of southern England as proxy indicators of paleoenvironmental and land‐use change

Abstract

Investigations of colluvial sequences infilling the dry valleys of the southern English chalk escarpment have been undertaken since the late 1950s. Chalkland environments are characterized by a rich prehistoric cultural record and, because of poor pollen preservation in the highly calcareous chalkland sediments, molluscan analysis of such deposits has frequently been undertaken to reconstruct past land use and environment. Archaeologists often base their interpretations of past chalkland environments on these reconstructions. In order to test the value of this proxy data source, seven dry valley systems in southern England were investigated using a combination of lithostratigraphic and biostratigraphic techniques. The results of this study demonstrate that patterns of sedimentation are similar within valley systems, but that the mechanisms and chronology of deposition vary between valleys. The differences are probably caused by a combination of factors, including variations in past land use, the impact of storm activity, and local topography. It can therefore be argued that it is unwise to use dry valley sequences and their accompanying biological assemblages for regional environmental reconstruction, although the data are invaluable when examining land use on a local level-the scale at which most archaeological projects in the United Kingdom are carried out. ᭧

Past Soil Erosion in Europe

“…Already before the medieval period the Pleistocene loess and Holocene soils were stripped off the slope completely. Studies on valley fills also revealed the long-term impact of agriculture on north-western European landscapes: Wilkinson (2003) investigated colluvial sequences infilling dry valleys of chalk escarpments in southern England. He shows that different spatial and temporal patterns of sedimentation are due to regional variations in past land use, storm impact and topography.…”

Étude morphologique et dynamique des têtes de vallon en milieux forestiers et cultivés : exemple dans le nord du Massif central français

“…Cette forte incision résulte de l'augmentation des précipitations et des débits associée au déclin de la fourniture sédimentaire liée à l'arrêt de la cryoclastie (Pastre et al, 2003). Les différences entre bassins versants peuvent s'expliquer par les conditions locales comme l'a montré K. N. Wilkinson (2003) pour les vallons secs du sud de l'Angleterre. Les matériaux issus de l'incision tardiglaciaire ne se retrouvent pas dans les têtes de vallon car ils ont été exportés vers l'aval.…”

Relation between radiocarbon, archaeological dating and sediment properties on the example of colluvial deposits (NE Poland)

“…Human settlement of the research area, followed by forest clearance and introduction of agriculture, triggered water soil erosion on slope and redeposition at footslopes and in dry valleys (Starkel, 1988(Starkel, , 2005Bork, 1989;Klimek, 2003;Zolitschka et al, 2003;Wilkinson, 2003). Numerous studies show a good correlation between radiocarbon age of colluvium and settlement stages (Sinkiewicz, 1993(Sinkiewicz, , 1998Twardy, 2002;Lang, 2003).…”