Buried late holocene paleosols of the nienshants cultural-historical monument in St. Petersburg

Abstract

Buried Late Holocene paleosols of the Nienshants historical monument at the junction of the Neva and Okhta rivers (St. Petersburg) have been studied. These soils developed from estuary deposits of the Littorina basin with abundant artifacts of the Neolithic and Early Iron ages (7-2 ka BP). The soil cover of the area consists of the mature dark humus profile gleyed soils on elevated elements of the mesotopography (3.0-3.5 a.s.l.) and dark humus gley soils in the local depressions (2.0-2.6 m a.s.l.). The soils are character ized by the low to moderate content of humus of the fulvate-humate type. The beginning of humus formation in the dark humus gley soil on the slope facing the Neva River is estimated at about 2600 yrs ago; for the dark humus profile gleyed soils of the studied paleocatena, at about 2000 and 1780 yrs ago; and for the dark humus gley soil, at about 1440 years ago. Judging from the spore-pollen spectra, the development of these soils took place in the Subatlantic period under birch and pine-birch forests with the admixture of spruce and alder trees. The gleyed horizons of the buried soil at the depth of 1.6-1.2 m on the Neva facing slope date back to the Late Subboreal period (2500-2600 yrs ago), when pine-birch-spruce forests were widespread in the area. The new data contribute to our knowledge of the environmental conditions during the Neolithic and Iron ages.