Holocene evolution of a lowland Scottish landscape: Kirkpatrick Fleming. Part III, fluvial history

Abstract

Mapping and radiocarbon dating of fluvial terrace fragments along the greater length of the Kirtle Water resulted in the definition of five major terrace surfaces. Correlations with proxy records of climate change (Part I) and anthropogenic activity (Part II) are made to understand causal mechanisms in fluvial behaviour. The limitations of such correlations are emphasized. The highest terrace (Kirtle I) is thought to be of Devensian Lateglacial age. The remaining four are of Holocene age. An early Holocene gravel aggradation (Kirtle II) may have been sustained from c. 7250 14C years BC until close to c. 455 cal. BC. The establishment of Alnus on floodplains may have led to channel stability. Incision after c. 3250 cal. BC may have been due to greater discharges at a time of deteriorating climate. Terrace Kirtle III is undated. Prior to aggradation of Terrace Kirtle IV, beginning at around cal. AD 300, a period of lowered fluvial activity and floodplain stability is recorded from c. 850 cal. BC. Anthropogenic activity is thought to be responsible for the diachronous initiation of aggradation of Terrace Kirtle IV. Terrace Kirtle V is late historic in age, but the cause cannot be readily isolated.