Late Glacial and Holocene in the south of Western Siberia: geochemical indices and pollen data in Kyrtyma Lake sediments

Abstract

This paper presents some conclusions of a study of a long-term lake sequence in the southwestern part of the Western Siberian Plain. Environment changes in the Holocene were identified according to geochemical indices, accumulation rate, plant macrofossils, and pollen data of sediment in Lake Kyrtyma. As a result, we firstly obtained the data on climatically conditioned changes of the sedimentation in the flat part of Western Siberia over at least the last 15 thousand years. Geochemical changes in the sediment properties clearly revealed climate change over the Late Glacial and the Holocene. Changes in the composition of macrophytes gave little independent information, while the pollen data are perfectly combined with the sedimentation features and serve as a reliable source for the reconstruction of vegetation changes and landscape. The transition to the Holocene was marked at about ∼12–11.2 ka BP, subsequent ongoing warming led to the aridest Holocene phase at ∼7.1–5.5 ka BP. Cooling and the resulting decrease in vaporation began at ∼5.5–4.9 ka BP, but a cardinal shift in sedimentation due to a gradual increase in precipitation was at ∼4.9–2.8 ka BP. The most significant increase in humidification and a cooling began at 2.8 ka BP.

Forest fires in southwest Western Siberia: the impact of climate and economic transitions over 9000 years

“…However, we found that the correlation between climate and fire was weak in the investigated peatbog between 9.0 and 4.0k cal a bp. For example, Stage I, which exhibited low fire activity, occurred in the early to mid‐Holocene, including the warmest and driest interval of 7.1–5.5k cal a bp (Ryabogina et al, 2019; Ryabogina et al, 2020; see ‘Changes in vegetation and climate during the Holocene’). Although we did observe a slight increase in fire frequency around 5.5–5.3k cal a bp , it probably had minimal impact on the overall indicators of fire dynamics.…”

“…Information on earlier changes in climate and vegetation in the vicinity of Oshukovskoe peatbog are available from studies of Lake Kyrtyma, located 7 km south (Ryabogina et al, 2019; Ryabogina et al, 2020). At the beginning of the Holocene, about 11.7k cal a bp , warming led to an increase in precipitation and elevated groundwater levels.…”

“…The aim of the present study was to compare the identified fire dynamics with data on regional vegetation, global climate trends in the Holocene and, in particular, the relationship between fires and human development in the area. We were able to make such a comparison thanks to previously published reconstructions of the sequence of natural changes in this area based on palynological data (Zakh et al, 2008(Zakh et al, , 2010Ryabogina et al, 2019Ryabogina et al, , 2020. In addition, the region has been quite well studied by archeoologists, which makes it possible to trace the connection of fires with the development of the territory and the specifics of economic activity in the past and up to the present.…”