RECONSTRUCTION OF THE LANDSCAPE EVOLUTION AT THE CARROWKEEL MEGALITHIC COMPLEX, IRELAND

The Carrowkeel megalithic complex in County Sligo represents one of the most important Neolithic (4000-2500 BC) passage tomb sites in Ireland. The cairns are located in a towering position within the largely peat covered upland plateaus of the Bricklieve Mountains. Pollen and loss-on-ignition analyses complemented by radiocarbon dating were performed on peat cores retrieved close to the megalithic cairns to reconstruct the prehistoric vegetation dynamics. Particular emphasis was placed on determining the onset of blanket bog formation.

The research revealed a succession from ferns and a few grassland taxa growing on shallow minerogenic soil, followed by the expansion of grassland dominated by Plantago lanceolata, grasses, and Fabaceae. The accumulation of deeper, organic rich soils and soil acidification supported the establishment of dry heath at around 800 BC. The appearance of Sphagnum and testate amoebae mark the subsequent transition to wet heathland at around 400 BC.

The palynological evidence suggests that the cairns were located in a barren limestone mountain range during the time of their construction in the earlier Neolithic when drier and warmer than present climatic conditions prevailed in Ireland. At the time, the Bricklieve Mountains were probably not unlike today's limestone pavement of the Burren in County Clare. While early farming took place in the fertile lowlands surrounding the karst moutain range, the Carrowkeel megalithic complex, widely visible in the Neolithic landscape, provided a focal point for ritual activities. The blanket bog, which dominates today’s landscape character, was only established in the late Bronze Age during a prolonged period of cool and wet climatic conditions in Ireland.