1. Sediments from Lake Cheko (Siberia), a possible impact crater for the 1908 Tunguska Event
- Author
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Luisa Forlani, G. Longo, Enrico Bonatti, Francesca Alvisi, Alina Polonia, Mariangela Ravaioli, S. Albertazzi, Carla Alberta Accorsi, Luca Gasperini, Fabio Sacchetti, L.Gasperini, E.Bonatti, S.Albertazzi, L.Forlani, C.A.Accorsi, G.Longo, M.Ravaioli, F.Alvisi, A.Polonia, and F.Sacchetti
- Subjects
LAKE CHEKO ,Palynology ,SIBERIA ,carbon ,Event (relativity) ,TUNGUSKA EVENT ,Sediment ,grain-size ,porosity ,magnetic susceptibility ,X-ray diffraction mineralogy ,organic C and N content ,d13C isotopic ratios ,palynology ,and radiometric (210Pb and 137Cs) age determinations ,Geology ,IMPACT CRATER ,Sequence (geology) ,Paleontology ,Impact crater ,cosmic body ,Epicenter ,Aquatic plant ,peat ,Lacustrine deposits ,explosion - Abstract
Cheko, a small lake located in Siberia close to the epicentre of the 1908 Tunguska explosion, might fill a crater left by the impact of a fragment of a Cosmic Body. Sediment cores from the lake's bottom were studied to support or reject this hypothesis. A 175-cm long core, collected near the center of the lake, consists of an upper similar to 1 m thick sequence of lacustrine deposits overlaying coarser chaotic material. 210Pb and 137Cs indicate that the transition from lower to upper sequence occurred close to the time of the Tunguska Event. Pollen analysis reveals that remains of aquatic plants are abundant in the top post-1908 sequence, but are absent in the lower pre-1908 portion of the core. These results, including organic C, N and delta 13C data, suggest that Lake Cheko formed at the time of the Tunguska Event.
- Published
- 2009
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