The chronology of Late Quaternary fluvial activity in part of the Milfield Basin, northeast England

Abstract

The sediment stratigraphy of a 4 m thick intercalated Holocene alluvial fill and valley floor peat at a site in the Milfield Basin, Northumberland, has been dated by a series of eight 14C assays, and related to a previously analysed pollen record. The sequence extends from the earliest Holocene until c. 2800 cal. BP. Prior to the onset of peat inception, substantial amounts of channel‐trenching can be demonstrated to have occurred in the Milfield Basin during the Loch Lomond Stadial. There is no measurable early Holocene accelerated fluvial activity, but a major flooding event occurred at c. 7500 cal. BP, much earlier than recorded elsewhere in the region. The explanation for this is not clear. However, the cessation of mid‐Holocene overbank sedimentation at c. 4000–3500 cal. BP is tentatively correlated with slope stability associated with woodland regeneration. © 1998 John Wiley & Sons, Ltd.

The chronology and long term dynamics of a low energy river system: the Kelvin Valley, central Scotland

“…Because the glaciofluvial surface is kettled, some parts of the valley floor beneath the Holocene fill may have lain below this glaciofluvial surface on deglaciation, but, kettle holes being isolated, the erosion by fluvial processes of sediment separating kettles along the thalweg nevertheless necessitated incision and valley widening. Incision of several metres from glaciofluvial terrace surfaces prior to deposition of the earliest Holocene sediments is common to northern British river systems Tipping, 1998Tipping, , 1999. The age of this major downcutting episode has been poorly defined because only events after incision have been dated.…”

“…In both the Milfield between c. 3500 and before 2800 cal. BP (Tipping, 1998). After this date the alluvial record is absent.…”

“…Within formerly glaciated areas such as Scotland ( Figure 1) the contrast in form can occur over very short distances because of sharp breaks of slope created first by glacial erosion and then by the infilling of valley floors with glaciofluvial sediment. Because such valley floor sediment fills with very high preservation potential lie directly below montane slopes, they provide critical records of long term landscape change in geomorphologically active regions (Tipping, 1998). Previous studies from southern Scotland in the Milfield Basin, north east of the Cheviot Hills (Tipping, 1998) and in the Moffat Basin at the head of Annandale (Tipping, 1999;Tipping et al, 1999) (Figure 1) described thick (4 -9 m) aggradations of intercalated valley floor peats and fine grained overbank deposits that infilled deep buried valleys incised into higher terraces of glaciofluvial sands and gravels.…”

“…BP, and it was assumed (Tipping, 1998) that, although sedimentation might have continued, the later sequence had been destroyed through mineralization of an organic soil, perhaps following 19th century agricultural improvement. The alternative interpretation that sediment was not deposited seemed unlikely (Tipping, 1998) given that elsewhere fluvial systems are seen as highly active in the last c. 3000 years (Macklin andLewin, 1993, 2003;Brown, 1997;Macklin, 1999;Lewin et al, 2005). This report provides new radiocarbon ( 14 C) dated sediment stratigraphic data from a third aggrading low energy fluvial system in Scotland, in the upper reaches of the Kelvin Valley in central Scotland (Figures 2, 3) to clarify the chronology and dynamism of fluvial and valley forming events and to explore cause in sediment generation.…”

An assessment of blanket mire degradation and Peatland Gully development in the Cheviot Hills, Northumberland

“…Around 4500 years BP a period of warming occurred (Briffa & Atkinson, 1997) coinciding with Bronze Age human activity in the uplands (Tipping, 1992). A cooling phase at 3000 years BP (Briffa & Atkinson, 1997) marked a period of forest regeneration in the hills and reduced human activity (Tipping, 1998). From 2000 years BP conditions similar to the present became established, interrupted by a brief warm episode at 1000 years BP, coinciding with renewed human modification of the upland landscape (Briffa & Atkinson, 1997).…”