Imprint of the Tunguska Event in sediments of Suzdalevo Lake (Evenkia, Russia) and an evidence against the impact origin of this water body
Abstrakt
In 1908, a massive explosion known as Tunguska event (TE) occurred in Central Siberia. The cause of the explosion has never been clearly explained and remains broadly discussed by the scientific community.
However, not only origin of TE, but also its environmental impacts are not yet known. We investigated fingerprints of the TE and related environmental changes in sediments of Suzdalevo Lake which is located near the TE epicenter.
Suzdalevo Lake did not exist before the exposion according to Evenki's knowledge and was considered as possible impact-origin lake. However, apart from oral testimony, we have no evidence of the formation of a lake as a result of the TE event.
Two sediment short-cores were retrieved from Suzdalevo Lake and dated using 210Pb, 137Cs, and 226Ra radioactive isotopes analyses. The sediments were also measured for major element composition (XFR-scanning).
To study possible effects of TE on the freshwater ecosystem, we performed diatom analysis and analysis of freshwater fauna remains. According to our preliminary results of dating, Suzdalevo Lake was formed before the TE.
However, TE evidence is preserved in both cores in geochemical and mikrozoological parameters.