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Sanna Alwmark

Sanna Alwmark

Postdoctoral fellow

Sanna Alwmark

An Early Jurassic age for the Puchezh-Katunki impact structure (Russia) based on 40Ar/39Ar data and palynology

Author

  • S. Holm-Alwmark
  • C. Alwmark
  • L. Ferrière
  • S. Lindström
  • M. M.M. Meier
  • A. Scherstén
  • M. Herrmann
  • V. L. Masaitis
  • M. S. Mashchak
  • M. V. Naumov
  • F. Jourdan

Summary, in English

The Puchezh-Katunki impact structure, 40–80 km in diameter, located ~400 km northeast of Moscow (Russia), has a poorly constrained age between ~164 and 203 Ma (most commonly quoted as 167 ± 3 Ma). Due to its relatively large size, the Puchezh-Katunki structure has been a prime candidate for discussions on the link between hypervelocity impacts and extinction events. Here, we present new 40Ar/39Ar data from step-heating analysis of five impact melt rock samples that allow us to significantly improve the age range for the formation of the Puchezh-Katunki impact structure to 192–196 Ma. Our results also show that there is not necessarily a simple relationship between the observed petrographic features of an impact melt rock sample and the obtained 40Ar/39Ar age spectra and inverse isochrons. Furthermore, a new palynological investigation of the postimpact crater lake sediments supports an age significantly older than quoted in the literature, i.e., in the interval late Sinemurian to early Pliensbachian, in accordance with the new radioisotopic age estimate presented here. The new age range of the structure is currently the most reliable age estimate of the Puchezh-Katunki impact event.

Department/s

  • Lithosphere and Biosphere Science

Publishing year

2019-05-29

Language

English

Pages

1764-1780

Publication/Series

Meteoritics and Planetary Science

Volume

54

Issue

8

Document type

Journal article

Publisher

Wiley-Blackwell

Topic

  • Geology

Status

Published

Project

  • Geochronology of impact structures - constraining syn- and post-impact processes using the 40Ar/39Ar and U-Pb techniques

ISBN/ISSN/Other

  • ISSN: 1086-9379