C - Lublin

conditions, existing at the first part of the third Millennium BC, had been changed
by more arid ones not long before the soil been covered by kurgan embankment.
About 150 years later the soil salinity increased. In the profile of the paleosoil
buried under the kurgan embankment 4260±120 BP, (Cal. 3016-2628 BC) the SO 4
content became three-five times higher, while the chloride content remained high
as well. The thickness of the carbonates accumulation zone reduced but the
carbonate content in the upper 50 cm layer grew up 6,5%. The morphological
forms of the CaCO 3 neoformations changed too. The size of calcareous nodules
decreased, with impregnation forms prevailing. The Fe-Mn oxide neoformations
were not observed in the soil as well as in all paleosols described below. The
prismatic structure of the paleosoil illuvial horizon B became less prominent,
which is evidence of solonetzic process extinction under the condition of intensive
water evaporation. Increasing the gypsum content also indicates the intensification
of ascending migration of water-soluble components in the soil profile, which is
typical of drought periods.
During the next one and a half century both the easily soluble salts and gypsum
evidently rose up gradually resulting in the formation of their accumulation zone
with the upper boundary at 70 cm deep at the end of the third Millennium BC. The
gypsum content in the paleosoil buried 4120±70 BP (Cal. 2871-2508 BC) was
2,4%. The sulphate concentration in the layer of 70-200 cm reached 1300-1400
ppm. The cloride concentration in the lower part of the soil profile considerably
increased. This can was due to either the salt re-distribution in the soil profile or the
ground water chemistry composition change with the ground water salinity
increasing. The great amount of soil carbonates moved to the upper 0-50 cm layer,
in which the average CaCO 3 content was 8,4% (Fig.3). All carbonates were in
impregnation form.
Development of climate aridization resulted in forming unusual soils, which
are not found within the modern soil cover of dry and desert steppe zones. Whereas
the modern background soils are light-chestnut soils with differentiated profile and
solonetzic horizon, the paleosols at the turn of the third and the second Millennium
BC (3960±40 BP, Cal. 2490-2409 BC) are characterized by undifferentiated profile
with indistinct boundaries between soil horizons, uniform color of soil-ground
mass, and considerable salinity. We proposed to refer these soils as “chestnut-like
soils”. In contrast to the paleosols described above in this soil the thickness of the
humus horizon reduced until 7 cm, resulted from, most likely, activation of the
wind erosion. The textural differentiation of the soil profile disappeared. The HClreaction
was observed at the level of the soil surface. The soil salinity considerably
increased, with the easily soluble salts forming another accumulation zone in the
horizon B. The upper border of the easily soluble salts accumulation zone was on
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