Holocene river and slope activity in the Visoko Basin, Bosnia-Herzegovina - climate and land-use effects

ABSTRACT Alluvial and colluvial deposits were investigated at prehistoric tells close to the Bosna River. The chronology is based on ten radiocarbon ages, five optically stimulated luminescence ages, and on the archaeological record. Fluvial activity of the Bosna River is indicated by overbank fines [ca. 5000 (+/- 1000) BC, 500 BC until today] and a phase of lateral displacement of the river bed with subsequent channel fills ca. 2000-500 BC. Early Holocene fluvial activity was probably triggered by climatic variability but might have promoted the expansion of Neolithic societies into the Visoko Basin. Mid- to late Holocene river activity occurred under increased climatic aridity but coincided with the expansion of prehistoric settlements to a wider area of the river basin on hard rocks in the adjacent mountainous areas. The destruction of the thin soil cover in the mountains is discussed as a probable trigger for enduring subsequent river activity. This is also indicated by a change in the geochemical signature of the alluvial sediments. The proposed mechanism might explain the mid to late Holocene river history in other regions. The potential of geochemical analyses and diachronous high-resolution archaeological records to make inferences regarding sediment sources and geomorphological processes is demonstrated. Copyright (c) 2013 John Wiley & Sons, Ltd.