The pattern and implications of interglacial fluvial sedimentation
The discussion of interglacial and post-glacial sequences presented demonstrates that a temporal pattern of fluvial sedimentation is repeatedly seen in lowland Britain. This pattern, presumably conditioned by a response to runoff and sediment supply, controlled ultimately by climate and its influence on vegetation, soils, precipitation and seasonality, is remarkably consistent for over 0,75 My and is operating today, albeit considerably modified by human activity.
The pattern presented below is divided into four temporal fluvial phases (Fph i – iv). These phases should not be seen as rigid or distinct time divisions (they are not time-equivalents of the vegetational substages of West, 1968 and West & Turner, 1968), but rather as broad periods that reflect steps in the evolution of valley fills. As such the phases may partially overlap or grade into one another, they will vary in length from interglacial to interglacial and they will be strongly influenced by local site, reach and valley conditions. The phases are illustrated on the following pages:
Fph i . Late-glacial – interglacial transition ( Substages late-glacial to I )
Fph ii . Full interglacial (Substage II )
Fph iii . Full interglacial (late Substages II – III )
Fph iv . Late interglacial rejuvenation and dissection ( late Substage III to Early-glacial )