A city against the current: A reconstruction of Holocene sea-level changes and the evolution of coastal landscapes in ancient Abdera (Thrace, Gr.)

Abstract

This paper presents an integrated Geoarchaeological approach to Holocene landscape change and socio-environmental interaction around ancient Abdera, a Greek colony in Aegean Thrace. A combination of remote sensing, geomorphological mapping, sedimentary coring, and radiocarbon dating was used to build the first detailed Holocene sea-level curve in the Northern Aegean, and to reconstruct the palaeogeographic evolution around Abdera from the Neolithic onwards. The discussion of these results, alongside the available archaeo-historical data, sheds new light on the role of historical and environmental factors in the rise and eventual decline of Abdera, thereby challenging previous narratives. This study is the first to detect evidence of the Neolithic landscapes in this coastal area being submerged by marine transgression c. 5000 cal. BC. A lagoonal landscape developed from the Neolithic until Greek colonists settled in the area c. 654 BC. The results presented here suggest that the relocation of the city in the 4th century BC was not caused by the silting up of the bay but was due to historical events. The coastal progradation only became significant after 300 cal. BC and accelerated in the following centuries. Based on the data acquired, it is hypothesized that this was due to anthropogenic forcing of the sedimentary systems both at local and regional levels, caused by the development of the productive activities of the colony. The evidence presented here demonstrates that while Abdera retained good access to the sea, its decline in the 4th c. AD was certainly due to the gradual shift of the economic axis inland. By 400 cal. AD the coastline was very close to its current position. The results of this study also add to the catalogue of known tsunamis in the Northern Aegean, by providing new evidence of a tsunami on this section of the Thracian coast in 544 AD.