Palaeoecology and geoarchaeology of the Varna Lake, northern Bulgarian Black Sea coast

Abstract

The coastal lakes are rich sources of biostratigraphic information that is very useful in palaeoecological reconstructions of climate changes and human impact on the natural vegetation. This information is of great importance for the archaeological descriptions of submerged praehistorical settlements found in the northern Bulgarian Black sea area. There are 4 archaeological sites in this area that have been palynologically studied for the last 30 years: the Durankulak Lake, the Shabla-Ezeretz Lake system, the Lake Bolata, as well as the Varna-Beloslav Lake system. Because of the lack of AMS radiocarbon dates for these sites, it was not possible to correlate adequately all palaeoenvironmental results with the available archaeological chronology.

Aimed to receive additional information on the Holocene vegetation dynamics and lake level changes, as well as on the anthropogenic impact during the Late Eneolithic and Early Bronze Age, the high-resolution spore-pollen analysis of AMS dated laminated sediments from a new Core 3 – Varna Lake was combined with analyses of dinoflagellate cysts, acritarchs, and other non-pollen palynomorphs.

The location of the core is close to several sites of submerged praehistorical settlements and the Varna Late Eneolithic (Chalcolithic) Necropolis, which is famous with the oldest hand-made gold treasure in the Worlds, and permits the palaeoenvironmental correlations of obtained results with available archaeological and geochronological data. The core is 995 cm long, but its palynologically investigated length is 870 cm. It contains dark grey clay and laminated sediments (varves). Seven samples of sediments were submitted for radiocarbon dating to the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility of Woods Hole Oceanographic Institution (WHOI). The dates have been calibrated using the program CALIB version 6.1.0 of using the IntCal09 curve. An Age Model for the sedimentation rate was created by the newest version 1.17.16. of the TILIA software.