CLIMATE CHANGES AND SOIL EVOLUTION IN DESERT STEPPE ZONE OF RUSSIAN PLAIN DURING THE BRONZE AGE

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-05-8 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 32, 77-84 pp, DOI: 10.5593/sgem2017/32/S13.011

ABSTRACT

The study of the soils buried beneath the Bronze Age kurgan mounds in the desert steppe zone of the southeastern part of the Russian Plain allowed establishing the features of the soil evolution and climate dynamics in the 3rd millennium BC. According to calibrated 14C data, the kurgans were constructed during period 2800-2100 cal yr BC: (Catacomb and Lola archaeological cultures). Morphological and chemical properties of buried soils and modern surface soils indicate that during the previous period (the end of Early Bronze Age), the climate in the region was similar to the modern one, and the Kashtanozems predominated in the soil cover. The first signs of climate aridization we noted in the soils buried in 28th century BC. Gradual climate aridization continued through much of second half of the third millennium BC. During this period, Solonetz spread widely, soil salinity and erosion rates increased. The heaviest droughts occurred at around 2200–2100 cal yr BC, resulting in strong wind erosions, soil salinization and deflation of the upper horizon of the soils of the watershed areas. In consequence of progressive erosion and salinization, in the end of third millennium BC, Cambisols were developed in the former Kashtanozems and Solonetz areas. A sharp change in natural conditions occurred in the 19th and 18th centuries B.C. At that time under increasing precipitation, desalinization occurred, the thickness of the humus layer and the content of organic carbon increased. The Cambisols disappeared from the soil cover, and Kashtanozem and Solonetz spread again.

Keywords: steppe, soil, Bronze Age, Kashtanozem, Solonetz