Obscure-bedded Ejecta Facies from the Popigai Impact Structure, Siberia: Lithological Features and Mode of Origin
2003; Springer Nature; Linguagem: Inglês
10.1007/978-3-642-55463-6_6
ISSN2365-0710
Autores Tópico(s)Methane Hydrates and Related Phenomena
ResumoThe lithology and distribution of proximal ejecta facies that formed during the late stages of formation of the Popigai impact crater, Siberia, are described. These deposits are distinct from other rock facies of the crater fill due to obscure bedding (or unclear layering), poor or moderate sorting, and some other specific lithological features (character of debris, presence of accretionary lapilli etc). Three types of such ejecta facies occur in the upper parts of the crater fill; these are are composed of lithic microbreccias and suevites (A type), suevites with minor tagamites (B type), and suevites (C type). Similar rock facies, according to previously published data, may be distinguished in some other impact craters (e.g., Ries, Sudbury, and Logoisk). The preliminary interpretation of the mode of origin of these ejecta facies are air fall (A), pyroclastic-like flow (B), and base surge (C) deposits, which resemble some features of volcanic pyroclastic formations. It is possible that similar rock facies may be found in the crater fill of some other well- preserved impact craters.
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