The Late Quaternary palaeoecological history of the Great Wold Valley

Bush, Mark Bennett

Geology; Sedimentology; Mineralogy
June 1986

Thesis or dissertation


Rights
© 1986 Mark Bennett Bush. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.
Abstract

The paucity of polliniferous deposits on the British chalklands has left something of a vacuum in the known vegetational history of the British Isles. Conflicting ideas of the past landscape of the chalklands have been  presented by archaeologists (e.g. Clark, 1936) and botanists (e.g. Tansley, 1939; Pigott and Walters, 1954). The Tansleyan view, i.e. that the chalklands were forested until the Bronze Age, has held sway. Tansley suggested  that the dominant species were Quercus and Fraxinus. This was challenged by the view that Tilia may have been a dominant on basic soils (Merton, 1970). Such palaeoecological evidence as exists would suggest that  woodlands covered the southern chalklands prior to Bronze Age disturbance, thus vindicating the Tansleyan  school.In this thesis data from a site lying on the Yorkshire Wolds are presented. For the first time a broad spectrum of palaeoecological information is presented from a British Flandrian chalkland deposit. Pollen, bryophytes, plant  propagules and macrofossil remains, mollusc and insect data form the basis for an environmental  reconstruction of the major water catchment area of the Yorkshire Wolds.This is complemented by a study of modern analogue sites where a vegetation survey had been undertaken.  Plant propagules, molluscs and bryophytes from the surface soil and modern pollen rain (trapped over a one  year period) were collected from each site. These data were incorporated into statistical analyses to compare  the changes in the fossil data with the range of known analogue habitats (after Lamb, 1984).Willow Garth, an ancient carr woodland in the Great Wold Valley, yielded fossil-rich deposits from the late-glacial  and Flandrian periods. Although the sedimentary history of this site would appear to be incomplete,  an exceptionally detailed image of the palaeoecological history of this valley emerges. The transition from the  late-glacial fen and tundra to the Pre-Boreal forest occurred at c. 9200 B.P.. However, the progression towards the mixed woodland of the Boreal forests appears to have been interrupted by the activities of Mesolithic man. It  is suggested that Mesolithic hunter-gatherers were 'managing' the woodlands to maximise the carrying capacity  of their game. One consequence of this activity was to prevent the forest canopy from closing over the  chalk grassland. Calcicolous grassland species were present throughout this period suggesting that the local  chalk grassland may never have been totally shaded out. If this was the case the chalk grasslands around the  Great Wold Valley would be of considerably greater antiquity than is generally supposed.During the late-Neolithic and the Bronze Age there is abundant evidence of anthropogenic disturbance with the  presence of agricultural weed taxa and pollen of Cerealia. Chalk grassland species are also represented in  both the faunal and floral records from this period. Cattle probably grazed the fen and the local wetland flora  reached a peak of diversity. In early Saxon times the fen started to dry out and it is suggested that its land use  may have changed from a grazed fen to an osier bed at c. 1200 B.P.

Publisher
Department of Geography, The University of Hull
Supervisor
Flenley, John
Sponsor (Organisation)
Nuffield Foundation; National Educational Research Centre Radiocarbon Committee
Qualification level
Doctoral
Qualification name
PhD
Language
English
Extent
Filesize: 22,353KB
Identifier
hull:5114
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