A POLLEN DIAGRAM, RADIOCARBON AGES AND EVIDENCE OF AGRICULTURE ON EXTWISTLE MOOR, LANCASHIRE

A pollen diagram is presented from an upland area (about 360 m a.s.l.) on the western slope of the Pennines above Burnley. Radiocarbon assays from the peat suggest that the diagram covers about the last 3000 yr. The recent practice of dating both the 'humin' and 'humic' fractions of a peat sample leads to problems of assigning dates, especially calibrated dates, to particular events. The evidence from the pollen curves is compared with known climatic, archaeological and historical evidence in an attempt to see whether a chronology based on the humin dates or one based on the 'weighted mean dates' is more reliable. The evidence suggests that for this site the humin dates are more realistic and indicate that although the site has been covered by peat from about 1000 BC there were clearance phases in the area in the Iron Age, the Roman Period and from the sixteenth century on.