Late Pleistocene deposits at Brimpton, Berkshire, England

Bryant, Ian; Holyoak, David T.; Moseley, Karl

doi:10.1016/s0016-7878(83)80015-7

Cited by 30 publications

(15 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At some cold-stage sites the assemblages consist mainly of macrofossils of terrestrial plants, for example during the Middle Devensian at Brimpton (Bryant, Holyoak & Moseley, 1983), but at others they are in a small minority (e.g. Worsley, et al, 1983).…”

Section: Discussionmentioning

confidence: 99%

“…The proportions of macrofossils from aquatic, waterside and terrestrial plants is more variable in fluvial deposits from the Pleistocene cold stages in England than from the interglacial deposits. At some cold-stage sites the assemblages consist mainly of macrofossils of terrestrial plants, for example during the Middle Devensian at Brimpton (Bryant, Holyoak & Moseley, 1983), but at others they are in a small minority (e.g. Worsley, et al, 1983).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Taphonomy of Prospective Plant Macrofossils in a River Catchment on Spitsbergen

Holyoak

1984

New Phytologist

View full text Add to dashboard Cite

SUMMARYRepresentation of recent plant parts in fluvial sediments and in the vegetation of a braided-river catchment on Spitsbergen was studied quantitatively in order to provide a model for taphonomy of plant macrofossils during cold stages of the British Pleistocene. The area studied on the Adventelva is in a region with continuous permafrost and on a river that has high (nival) peak discharges in early summer, features that were also present in the British lowlands during the Pleistocene cold stages.Deposition of 'prospective macrofossils' in silts of channels on the Adventelva floodplain occurred mainly during the decline from the early summer peak of discharge. Surface runoff overland was much the most important process by wKich 'prospective macrofossils' reached river channels, and this accounts for them giving a surprisingly even overall representation of the abundance of similar parts in the vegetation. Taxa having 'prospective macrofossil parts' that were under-represented in the deposits had parts that were: (a) very small, (b) of soft or perishable texture, (c) firmly attached to stems, (d) neither deciduous nor renewed annually, or (e) they were plants growing on the river floodplain. Taxa with parts over-represented in the deposits were: (a) those with parts that break into numerous identifiable fragments, or (b) they were plants growing in localized areas of late snow-lie.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Taphonomy of Prospective Plant Macrofossils in a River Catchment on Spitsbergen

Holyoak

1984

New Phytologist

View full text Add to dashboard Cite

show abstract

“…They are : (1) the unstable environmental and climatic conditions, (2) the too dry and continental climate, (3) windy conditions, (4) heavy grazing pressure from the large mammals such as mammoth, woolly rhinoceros and bison, (5) the fact that trees need an adequate soil development, (6) the suddenness and intensity of the climatic warming, and (7) the shortness of the interstadial events that left too little time for trees to migrate from their refuges in southern Europe. Many fossil £oras and faunas from the British Isles, that date from the period between 35 and 26 ka BP (such as Colhoun et al, 1972;Bryant et al, 1983;Briggs et al, 1985;Coope, 1986;Whittington and Hall, 2002) suggest cold, often very continental climatic conditions, with both minimum mean July temperatures and mean July temperatures at or just below 10 ‡C. Under these conditions it is not surprising that trees were absent.…”

Section: Climatementioning

confidence: 99%

Flora, fauna and climate of Scotland during the Weichselian Middle Pleniglacial – palynological, macrofossil and coleopteran investigations

Bos

Dickson

Coope

et al. 2004

Palaeogeography, Palaeoclimatology, Palaeoecology

View full text Add to dashboard Cite

Thin lenses of organic-rich material, on the upper surface of a layer of glacio-fluvial deposits have been studied in an open cast coal-mine near Sourlie, western Scotland. Radiocarbon dates on antler fragments, plant debris and bulk organic matter from silt, showed that the sediments accumulated between ca. 33 500 and 29 000 14 C yr BP, during a period when this part of western Scotland was free of glaciers. The organic-rich sediments yielded a very rich flora and fauna and in total about 160 plant taxa and 61 coleopteran taxa were recorded together with other invertebrates. The Sourlie flora is one of the richest late Middle Weichselian floras yet studied within the British Isles. Leg bones of Coelodonta antiquitatis (woolly rhinoceros) and Rangifer tarandus (reindeer) were also found at the site. During this period, the landscape was treeless and the vegetation could be characterised as an intermediate between a low shrub tundra and sedge^grass^moss tundra. Both the flora and arthropod fauna suggest that during formation of the organic-rich layers at Sourlie, mean July temperatures were 9^10 ‡C. The flora suggests also that at the beginning of formation of these layers, minimum mean July temperatures increased from 7 to 9^10 ‡C, but later dropped again to 7^8 ‡C. A possible time correlation with one of the warmer periods of the Dansgaard^Oeschger cycles in the stable oxygen isotope record of the Greenland ice cores during this period is proposed. The arthropod fauna suggests that mean January temperatures were somewhere between 334 and 311 ‡C. Mean annual temperatures lay probably between 31 and 310 ‡C, which implies the possible presence of discontinuous or continuous permafrost in the area. During winter, a protective snow cover of varying thickness probably enabled perennial plants, especially shrubs, to survive. ß

show abstract

“…Channel confluences are present in every drainage basin and are sites at which significant changes in downstream hydraulic geometry must occur. Within the last 15 years increasing attention has been paid to these sites, building from considerations of jet mixing and junction flow dynamics (Taylor, 1944;Greated, 1964;Webber & Greated, 1966;Itakura, 1972;Soong, 1976;McGuirk & Rodi, 1978;Lin & Soong, 1979;Best & Reid, 1984, 1987Best, 1987) through to investigations of confluence bed morphology (Komura, 1973;Mosley, 1975Mosley, , 1976Mosley, , 1982Mosley & Schumm, 1977;Dolan, Howard & Trimble, 1978;Kjerfve, Shao & Stapor, 1979;Ashmore, 1979Ashmore, , 1982Ashmore & Parker, 1983;Kennedy, 1982Kennedy, ,1984Best, 1985Best, , 1986) and confluence facies (Frostick & Reid, 1977;Bryant, Holyoak & Moseley, 1983;Alam et al, 1985;Best, 1985;Best & Brayshaw, 1985). Some implications of channel confluences within the drainage basin have also been discussed in relation to channel width adjustments (Miller, 1958 ;Richards, 1980;Roy & Woldenberg, 1986;Roy & Roy, 1988), and downstream grain size changes (Miller, 1958;Lodina & Chalov, 1971;Knighton, 1980Knighton, , 1982.…”

Section: Introductionmentioning

confidence: 99%

Sediment transport and bed morphology at river channel confluences

1988

View full text Add to dashboard Cite

River channel confluences form important morphological elements of every river system, being points at which rapid changes in flow, sediment discharge and hydraulic geometry must be accommodated. This article presents results of a quantitative investigation of sediment transport at channel confluences accomplished through both scaled laboratory flume simulation and complementary monitoring of a natural channel confluence.Bed morphology at channel confluences is characterized by three distinct elements : avalanche faces at the mouth of each confluent channel, a deep central scour and a bar within the separation zone formed at the downstream junction corner. These elements are controlled predominantly by the confluence angle and the ratio of discharges between the tributary and mainstream channels. As confluence angle and discharge ratio increase, the sediment contributions from the confluent channels are progressively segregated in their paths through the junction, with sediment being transported around rather than through the centre of the confluence. This segregation of sediment loads is accompanied by the retreat of the main channel avalanche face from the confluence, an increase in the scour depth, a change in the orientation of the scour and an increase in the size of the separation zone bar. Field measurements closely replicate the flume simulation.A model of sediment transport and bed morphology links these features to the fluid dynamics of these sites. An understanding of confluence dynamics is important not only in considerations of channel morphology and design criteria but must form the basis for the interpretation of confluence sediments in the ancient record.

show abstract

Late Pleistocene deposits at Brimpton, Berkshire, England

Cited by 30 publications

References 31 publications

Taphonomy of Prospective Plant Macrofossils in a River Catchment on Spitsbergen

Taphonomy of Prospective Plant Macrofossils in a River Catchment on Spitsbergen

Flora, fauna and climate of Scotland during the Weichselian Middle Pleniglacial – palynological, macrofossil and coleopteran investigations

Sediment transport and bed morphology at river channel confluences

Contact Info

Product

Resources

About