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Scanning micro-X-ray fluorescence analysis with synchrotron radiation was applied to obtain the depth-variation profiles of element compositions of banded clays in Peyungda Lake (Krasnoyarsk krai, Evenkia) located 30 km southwest of the epicenter of the Tunguska event (1908). The age model was confirmed by a dated layer of anomalous thickness related to the fall and explosion of the Tunguska Cosmic Body (TCB). The variations in the element content in dated core layers were compared with the instrumental meteorological observation data over the last century. The regional average annual temperature and element compositions of the coeval bottom sediments (transfer function) were found to be interrelated. The approximation of the transfer function to the sampling depth of the sedimentary section made it possible to reconstruct the air temperature in the studied region over the past 1000 years. The average annual temperature reconstructions in the study area compared with the global temperature reconstructions in the Arctic region for the same period made it possible to reveal general trends and extreme values. [ABSTRACT FROM AUTHOR]

The distribution of charcoal particles >100 µm in size, which are indicators of plant combustion in ambient territories, are analyzed in sediments of Shira and Uchum lakes located in southern Siberia in the steppe zone of the North Minusinsk Basin (Republic of Khakasiya and Krasnoyarsk krai). The age of the lakes is to 1400 and 500 years, respectively. The lacustrine sediments contain charcoal particles of three types. Particles of group 1 have elongated morphology and are interpreted as remnants of grassy plants and/or conifers. Particles of group 2 look like thin plates similar to relics of leaves and bark of trees. Group 3 is composed of various irregular volumetric particles, which are probably relics from wood and coal combustion. The particles of group 1 are mostly indicators of natural fires, and their amount is almost constant in the current period. The amount of charcoal particles of groups 2 and, mostly, 3 has strongly increased in past 100 years, which reflects an increase in the amount of artificially combusted wood and coal in the vicinities of the lakes in the present-day industrial period. An increase in the contribution of the charcoal particles to lacustrine sediments over the past 100 years has been detected for the first time for this region, which is unprecedented for the period of study. This is evidence of the anthropogenic impact on the dynamics of charcoal particles in lacustrine sediments. Our data can be useful for reconstruction of the dynamics of natural fires and the paleoclimate in southern Siberia in the Late Holocene. [ABSTRACT FROM AUTHOR]

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X23070279 [ABSTRACT FROM AUTHOR]

An anomalous layer enriched with chemical elements indicating the presence of terrigenous matter was discovered in the sediment core of Zapovednoe Lake located 60 km from the epicenter of the Tunguska event (1908) using synchrotron radiation X-ray fluorescence spectroscopy (SR–XRF). Radioisotope measurements indicate that the age of the layer is consistent with the date of the catastrophe. Apparently, the anomalous layer was formed as a result of an intense terrigenous matter inflow from the water catchment area due to massive forest falls and subsequent wildfires caused by the Tunguska event. Thus, it is established that targeted searches for microparticles of extraterrestrial origin can be carried out in the discovered and dated anomalous bottom sediment layer. [ABSTRACT FROM AUTHOR]