ORGANIC-CARBON CONTENT IN THE LATE PLEISTOCENE AND HOLOCENE FOSSIL SOILS (RECONSTRUCTION FOR EASTERN-EUROPE)

The organic carbon content of soil and paleosols in the region of the East European plain (EEP) is examined in this study to assess the mass of carbon stored in paleosols formed during three intervals in the pa st: Holocene (6-7 ka BP), Valday glaciation (18-20 ka BP) and Eemian i nterglaciation (Mikulino, 120-125 ka BP). For the main part of the EEP , reconstructions of soil cover are primarily based on results of actu al paleosol profile studies and their geochemical properties. In regio ns where fossil soils are not well preserved: the reconstructions are based on the correlation between soil characteristics and vegetation c over. The cartographic reconstruction of the soil type distribution se rved as a basis for the estimation of humus carbon stocks in the fossi l soils. The humus carbon content in l-m layer of the soils, which rep resent modem analogues of paleosols, was used to estimate the carbon c ontent of paleosols. The geographical location of soil zones and their areas differ from the present-day ones in all the cases. Estimations of humus carbon storage in the past soils were made within the limits of the key region (polygon) of the East European plain (between 46 deg rees N and 65 degrees N and 25-30 degrees E and 55 degrees E), using a n equal-area projection. The key area covers 3.2 x 10(6) km(2). For th e present day total quantity of soil humus carbon storage within the l imits of the key-region is 41 Gt, that for the Eemian (Mikulino) inter glacial maximum 56 Gt (137% of the present day value), for the Last Gl acial maximum 6 Gt (15%), and for the Holocene optimum 49 Gt (120%). ( C) 1998 Elsevier Science B.V. All rights reserved.