Holocene river development and environmental change in Upper Wharfedale, Yorkshire Dales, England

This paper provides the first radiometrically dated evidence of Holocene al luvial landform development in Upper Wharfedale, Yorkshire Dales. Four rive r terraces are identified. Terraces 1 and 2 are closely linked to Late Deve nsian and early Holocene environmental change, with gravel reworked from lo cal glacial and periglacial sources prior to cementation by carbonate-rich waters. U-series dating of cement provides age estimates for cementation of between ca. 5.1-7.4 kyr BP for Terrace 1 and ca. 3.6-->8.0 kyr BP for Terr ace 2. U-series dating of tufas overlying Terraces 1 and 2 produced ages of ca. 4.2-4.5 kyr BP and ca. 2.1-2.2 kyr BP respectively, and provide upper age limits for terrace formation. Terrace 3 marks a change in sediment cali bre, supply and sedimentation style, and C-14 dating suggests that the prin cipal source of fine-grained material may be agricultural expansion in the Yorkshire Dales from ca. AD 600 (1350 cal. yr BP). Radiocarbon dates indica te that Terrace 4 was deposited from the eleventh century, with initiation of the contemporary floodplain between the fifteenth and seventeenth centur ies AD. Both these lowest units contain sediments contaminated with heavy m etals as a result of mining activities within the catchment. The evidence p resented in this study is comparable to that of research undertaken in upla nd environments elsewhere in northern and western Britain, thereby adding t o the corpus of information currently available for evaluating the fluvial geomorphological response to climate and vegetation change during the Holoc ene. Copyright (C) 2000 John Wiley & Sons, Ltd.