EVOLUTION OF SOILS AND LANDSCAPES OF WETLANDS IN THE UPPER VOLGA LOWLAND IN THE HOLOCENE: MULTIDISCIPLINARY STUDY

An integrative study of fluviolacustrine and bog deposits of wetlands of Upper Volga Lowland including series of buried soils and evidences of Early Man activity was made to reconstruct the climate and palaeohydrological change in the Central Russia during the last 11,000 14C years.

Study sites are located within Zabolotskoe peatland developed in place of the former bottom of a periglacial palaeolake Tverskoye. It is shown that the regional time-space dynamic of soils and landscapes was tightly related to initial topography of dried palaeolake bottom.

Soil formation began not later than 10330 14C BP on the forest-free plain with inherited topography of palaeolake bed. The carbonated organic rich well-structured soils were widely developed. According to the interpretation of palynological spectra from key sections and the oxygen isotope composition of bone phosphate the annual temperature was 5° and 10° lower than at present, respectively.

During the Preboreal up to the beginning of the Atlantic, birch and pine forests developed successively leading to soil leaching. Acid humic-illuvial soils were formed. Impact of Mesolithic settlements resulted in soil disturbance.

In the Atlantic forests are widespread, while Luvisols on loams and Podzols on sands, and raw-humus soils in the depressions under alder forests were formed. Frequent forest fires are assumed to have occurred around 7500 BP.

Around 6000 BP bogging in depressions began; on the high sites (0.5 m above) Luvisols and Podzols development was continued, and human used this plots actively. At the Atlantic/Subboreal transition complex soil cover from peaty boggy soils, Luvisols and Podzols was formed.

Around 2600 BP total flooding interrupted soil development through lowland area bordering the Klin-Dmitrov Heights and lower than 130 m a.s.l. Shallow flow-through cold lake was formed.

Not later than 1900 14C BP a wet plain with temporary water channels, free and cut-off meanders and local bog areas were formed.

Around 730 - 640 BP alder and birch forests spread widely. Relief intensity decreased due to ongoing peat accumulation.

The present time is characterized by ground water-level rise and secondary soil carbonatization and gypsum formation.

Supported by the Netherlands Organization for Scientific Research (NWO). Project 047.009.002.