Middle to late Holocene lake level changes of Lake Sevan (Armenia) – Evidence from macro and micro plant remains of Tsovinar-1 peat section

Abstract

In the Caucasus, peat deposits exposed near Lake Sevan (Armenia) provide a Middle to Late Holocene record of lake level fluctuations. The Tsovinar-1 section at the southern shore of Lake Sevan in the Armenian Highlands reveals a well-dated and divers pollen and carpo-flora covering a time span from 6000 BC to 900 AD. The abundances of pollen of forest taxa in relation to steppe vegetation indicate climatic changes through time. In parallel, the presence and number of fossils of aquatic and wetland plants, both in micro and macro floras, provide information about the presence of water and allows estimating changes of water depth. Characteristic taxa pointing to deeper water at Tsovinar-1 are Myriophyllum sp., Ceratophyllum demersum, and several species of Potamogeton. In shallow water, Persicaria amphibia,Sparganium sp., and Typha sp. dominate. In fluctuating water and wetlands those plants are replaced by Menyanthes trifoliata, Ceratophyllum submersum, Alisma sp., and others. High lake levels can be inferred at 6000−5000 BC, 1700−900 BC and 200−900 AD and are associated with humid climate and the development of forest vegetation. Low lake levels occurred at 4000−2600 BC and 600 BC−100 AD corresponding to epochs of decreased humidity and expanded steppe vegetation. Macro and micro remains of plants from the Tsovinar-1 site serve as reliable sources of information for determining environmental changes over time, which are in accordance with archaeological data from the region showing the effects of lake level changes on human activities․