Palaeoecology and Geoarchaeology of Varna Lake, Northeastern Bulgaria

Abstract

Palaeoenvironmental data from the high-resolution spore-pollen analysis of laminated sediments from newly-taken Core 3 ‐ Varna Lake were combined with analyses of dinoflagellate cysts, acritarchs and other non-pollen palynomorphs (NPP), including fossil algal and fungal remains. The location of the core is close to submerged prehistorical sites and permits the palaeoenvironmental correlations of obtained results with available archaeological and geochronological data. The established Age Model shows that the accumulation of lake sediments started after 7870 cal. BP and is connected with a rise of the Black Sea level. One-hundred-ninety-cm-long molluskan shell hash layer of Mytilus galloprovincialis covers the interval from 7776 to 6183 cal. BP. The mixed oak and hornbeam forests dominated the vegetation cover during the Atlantic, Subboreal and Subatlantic chronozones of the Holocene. An important change in the forest composition occurred at ca 5598 cal. BP, when Carpinus betulus increased its spreading due to climatic changes. The high-resolution reconstruction of palaeovegetation also reveals the extent of anthropogenic influence in Varna Lake area. Two periods of significant presence of pollen from cultivated cereals, weeds and ruderals were identified. According to the available AMS-radiocarbon data, these periods are attributed to the Late Eneolithic and Early Bronze Age. The anthropogenic impact on the natural vegetation has been identified by deforestation and agricultural practice. The Transitional period without human activities between these two periods lasted ca 319 years