Evidence of Late Devensian and early Flandrian processes and environments in the Idle Valley at Tiln, North Nottinghamshire

Abstract

SUMMARY This paper elucidates the late Pleistocene and early Flandrian environmental history of the Lower Idle Valley through sedimentological, palaeobiological and radiometric dating studies of fluvial and aeolian deposits. The lower part of the sequence comprises braided river sands and gravels with silty peats infilling a scour hollow in their upper surface. Coleopteran and palynological analyses of the organic sediments indicate deposition in a slow moving or static water body with fringing reeds, sedges and substantial beds of wet moss. Away from the water, the vegetation was open and probably of grassland with few trees. Radiocarbon dating indicates accumulation of organic material started towards the end of the Dimlington Stadial, c. 13,500 cal bp. A cryoturbated, podsolized sandy clay with plant matter was developed on the sands and gravels and is akin to an ‘Arctic Structure Soil’. The sandy clay parent material on which the soil was developed is suggested to have originated in a lacustrine environment, tentatively linked to the Lake Humber complex. The palaeosol is buried, in turn, beneath coversands, the uppermost part of which is reworked. Thermoluminescence (TL) age determinations show that the coversands started to accumulate around 13,700 bp, probably in response to climatic deterioration prior to the Loch Lomond Stadial. Reworking began around 8,500 years ago.