Studies in the Holocene Vegetation History Of
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STUDIES IN THE HOLOCENE VEGETATION HISTORY OF WENSLEYDALE by ANNE HONEYMAN Submitted in accordance with the requirements for the degree of Ph.D. The University of Leeds July 1985 School of Geography i SUMMARY Total and arboreal pollen diagrams have been prepared for three blanket bog sites and one valley bog in the Wensleydale area of the Yorkshire Dales. Local pollen assemblage zones have been defined for each site using numerical methods, and these have been correlated to give regional pollen assemblage zones. A computer program has been developed to calculate and plot the palynological data, and an absolute chronology has been established for the pollen diagrams from a series of twenty radiocarbon dates. Detailed humification profiles have been produced for each site to assist in the interpretation of the pollen records, and chemical analyses have also been carried out for the valley bog site. The regional zones have been used as the basis for a discussion of the Holocene vegetation history of Wensleydale. The palynological, radiocarbon, humification, chemical and archaeological/historical evidence is drawn together to provide a comprehensive study of the vegetation changes which have occurred over the approximately 9,000 years covered by the pollen records. By adopting a holistic approach to interpretation, it has been shown that man has been an important influence on the landscape of Wensleydale throughout this entire period. Possible anthropogenic causes are put forward for a number of vegetation changes previously assumed to be of climatic origin. ACKNOWLEDGEMENTS I would like to thank first of all my supervisor, Or. R. T. Smith, for all his help and advice throughout my period of research. The time and effort he has devoted to this project are much appreciated. I am also grateful to all the friends and colleagues who assisted with the fieldwork, and to the landowners who allowed access to their property. In addition I would like to thank the NERC Radiocarbon Laboratory for providing the radiocarbon dates, and Or. D. D. Harkness in particular for his advice and assistance on this aspect of the research. I am also much obliged to Dr. H. J. B. Birks, who provided copies of his zonation programs for my use. Finally, I must give special thanks to my husband, John Parsons, for his endless support and encouragement as well as practical help. This work was carried out during the tenure of a University of Leeds research studentship. CONTENTS Fa9e Summary i Acknowledgements ii Contents iii List of Figures vii Abbreviations ix CHAPTER 1: INTRODUCTION 1 1.1 Aims 2 1.2 The study area 4 1.3 Previous palaeoecological studies in the 7 Pennines CHAPTER 2: PHYSICAL BACKGROUND 16 2.1 Geology and topography 17 2.1.1 Carboniferous stratigraphy 17 2.1.2 Structural geology and mineralisation 22 2.1.3 The Quaternary period 22 2.2 Climate 25 2.2.1 Temperature 25 2.2.2 Precipitation 26 2.2.3 Wind 26 2.3 Soils 28 2.4 Vegetation 31 CHAPTER 3: HISTORICAL BACKGROUND 37 3.1 The Palaeolithic 38 3.2 The Mesolithic 39 3.3 The Neolithic 45 3.4 The Bronze Age 51 .. 3.5 The Iron Age 58 CONTENTS (continued) 3.6 The Roman Period 65 3.7 The Anglo—Saxon and Scandinavian Period 69 3.8 The Norman Settlement and the Monastic Period 75 3.9 The Post—Monastic Period 81 CHAPTER 4: THE FIELD SITES 88 4.1 Choice of sampling sites 89 4.2 Description of the sampling sites 92 4.2.1 Whirley Gill 94 4.2.2 Fleet Moss 97 4.2.3 Penhill 100 4.2.4 Thornton Mire 105 CHAPTER 5: CONSTRUCTION, ZONATION AND DATING OF THE POLLEN 119 DIAGRAMS 5.1 Construction of the pollen diagrams 120 5.1.1 Laboratory techniques 120 5.1.2 Choice of total pollen count 120 5.1.3 Choice of pollen sum and calculation 123 of percentages 5.1.4 Production of the pollen diagrams 124 5.2 Zonation of the pollen diagrams 126 5.2.1 Definition of pollen zones 126 5.2.2 Numerical zonation methods 128 5.2.3 Zonation of the Wensleydale pollen 130 diagrams 5.3 Radiocarbon dating 136 CHAPTER 6: THE POLLEN ASSEMBLAGE ZONES 138 6.1 Local pollen assemblage zones 139 6.1.1 Whirley Gill 139 6.1.2 Fleet Moss 149 CONTENTS (continued) 122.98 6.1.3 Penhill 158 6.1.4 Thornton Mire 164 6.2 Regional pollen assemblage zones 173 CHAPTER 7: INTERPRETATION AND DISCUSSION OF THE VEGETATION 175 HISTORY OF WENSLEYDALE 7.1 Zone Wensleydale I 176 7.1.1 Description 176 7.1.2 Interpretation 177 7.2 Zone Wensleydale II 187 7.2.1 Description 187 7.2.2 Interpretation 188 7.3 Zone Wensleydale III 197 7.3.1 Description 197 7.3.2 Interpretation 198 7.4 Zone Wensleydale IV 215 7.4.1 Description 215 7.4.2 Interpretation 220 7.5 Zone Wensleydale V 243 7.5.1 Description 243 7.5.2 Interpretation 247 CHAPTER 8: SUMMARY OF CONCLUSIONS 279 8.1 Evaluation of subsidiary techniques 280 8.1.1 Humification analysis 280 8.1.2 Chemical analysis 281 8.1.3 Computerized calculation and presentation 281 of pollen data 8.1.4 Numerical zonation methods 282 8.2 The Holocene vegetation history of Wensleydale 283 CONTENTS (continued) age BIBLIOGRAPHY 287 APPENDICES 304 1. Field and laboratory techniques 304 2. Pollen sample sizes 312 3. Composition of the 1 Varia' curves 315 4. POLLPLOT manual 319 5. The radiocarbon dates 320 LIST OF FIGURES 2E98 Figure 1.1 The location of Wensleydale 5 Figure 1.2 General map of the study area 6 Figure 2.1 The geology of Wensleydale 18 Figure 2.2 The Yoredale succession of the Askrigg Block 20 Figure 2.3 The vegetation of Wensleydale 32 Figure 3.1 Mesolithic, Neolithic and Bronze Age sites and 42 finds in Wensleydale Figure 3.2 Iron Age and Romano—British sites in Wensleydale 61 Figure 3.3 The Anglo—Saxon and Scandinavian place—names of 71 Wensleydale Figure 4.1 The location of the sampling sites 91 Figure 4.2 Key to stratigraphic symbols 93 Figure 4.3 The Whirley Gill pollen analysis site 95 a) General View b) Close—up of the sampling site Figure 4.4 The Fleet MOSS pollen analysis site 98 a) General view b) Close—up of the sampling site Figure 4.5 The prehistoric enclosures on Penhill 101 Figure 4.6 The Penhill pollen analysis site 103 Figure 4.7 Sketch map of Penhill, showing the sampling site 104 in relation to the prehistoric enclosures Figure 4.8 Sketch map of Thornton Mire, showing the sampling 106 site in relation to the prehistoric enclosures and cairn Figure 4.9 The Thornton Mire pollen analysis site: general view 108 LIST OF FIGURES (continued) fE9e Figure 4.10 The stratigraphy of Thornton Mire 110 Figure 4.11 Pollen content of the Thornton Mire basal samples 111 Figure 4.12 The Thornton Mire pollen analysis site: close—up 113 of the sampling site Figure 4.13 Thornton Mire chemical analysis results 115 Figure 5.1 The variation in pollen proportions with total 122 pollen count Figure 5.2 Whirley Gill zonation 132 Figure 5.3 Fleet Moss zonation 133 Figure 5.4 Penhill zonation 134 Figure 5.5 Thornton Mire zonation 135 Figure 6.1 Whirley Gill total pollen diagram 140 Figure 6.2 Whirley Gill arboreal pollen diagram 141 Figure 6.3 Fleet Moss total pollen diagram 150 Figure 6.4 Fleet Moss arboreal pollen diagram 151 Figure 6.5 Penhill total pollen diagram 159 Figure 6.6 Penhill arboreal pollen diagram 160 Figure 6.7 Thornton Mire total pollen diagram 165 Figure 6.8 Thornton Mire arboreal pollen diagram 166 Figure 6.9 Correlation of the Wensleydale pollen records 174 Figure 8.1 Summary of the Holocene vegetation history of 284 Wensleydale ix ABBREVIATIONS The following abbreviations are used throughout the thesis:— AP Arboreal Pollen NAP Non—Arboreal Pollen TP Total Pollen B.P. (Years) Before Present, i.e. years before the standard radiocarbon zero year of 1950 L.P.A.Z. Local Pollen Assemblage Zone R.P.A.Z. Regional Pollen Assemblage Zone On the pollen diagrams, the names of some pollen and spore types are abbreviated as follows:— JUNIPER Juniperus ERICA. Ericaceae CYPER. Cyperaceae GRAMIN. Gramineae PLANTAGO Plantaqo lanceolate RUMEX Rumex acetosella type CHENO. Chanopodiaceae ROSA. Rosaceae FILIP. Filipendula POTEN. Potentilla ARTEM. Artemisia UMBELL. Umbelliferae CARYOPH. Caryophyllaceae COMP. L. Compositae Liguliflorae COMP. T. Composites Tubuliflorae ABBREVIATIONS (continued) RANUNC. Ranunculaceae DIPSA. Dipsaceae POLYGON. Polygonaceae SAXIFRA. Saxifragaceae PRIMULA. Primulaceae HEDERA Hedera helix RUBIA, Rubiaceae LEGUM. Leguminosae MENYAN. Menyanthes trifoliata MYRIOPH. Myriophyllum alterniflorum POTAMO. Potamoqeton PTERID. Pteridium abuilinum FILI, Filicales 1 CHAPTER 1: INTRODUCTION 1.1 Aims 1.2 The study area 1.3 Previous palaeoecoloqical studies in the Pennines INTRODUCTION 1.1 Aims Most of the palaeoecological research so far carried out in the Pennine area has been focussed on either the southern Pennines of Derby- shire and south Yorkshire, or the northern Pennines of Durham and North- umberland (see section 1.3). The Yorkshire Dales, in the central area of the Pennines, have received comparatively little attention. Palyno- logical studies have covered the Nidderdale Moors (Tinsley, 1972), parts of Wharfedale (Raistrick and Blackburn, 1938; Walker, 1956) and the Craven area (Pigott and Pigott, 1959; Gosden, 1968; Jones, 1977; R. T. Smith, 1985, in press), but no work of this nature has been done in the more northerly dales, of which Wensleydale is the most extensive. This is probably due to difficulty of access from the centres of research, as Wensleydale in particular has both polliniferous peat deposits and an interesting situation and historical background to recommend it for detailed palaeoecological study.