Dissemin is shutting down on January 1st, 2025

Published in

Wiley, Meteoritics & Planetary Science, 5(32), p. 629-636, 1997

DOI: 10.1111/j.1945-5100.1997.tb01548.x

Links

Tools

Export citation

Search in Google Scholar

A Late Triassic age for the Rochechouart impact structure, France

Journal article published in 1997 by Simon P. Kelley ORCID, John G. Spray
This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

Full text: Download

Green circle
Preprint: archiving allowed
Orange circle
Postprint: archiving restricted
Red circle
Published version: archiving forbidden
Data provided by SHERPA/RoMEO

Abstract

Abstract— Argon-40/Argon-39 laser spot fusion dating of pseudotachylyte from the ∼25 km diameter Rochechouart impact structure of western-central France yields a matrix age of 214 ± 8 Ma (2s̀). Field evidence indicates that the pseudotachylyte was generated during the modification stage of the impact process, probably during transient cavity collapse. This new age is considerably older than the previously accepted age of 186 ± 8 Ma for this structure, which was obtained from hydrothermally-altered melt sheet samples. The new age is in accordance with earlier paleomagnetic and fission track data, which indicated that Rochechouart was formed during the late Triassic. Moreover, the new determination is in agreement with the regional geological setting and field relations of the structure. The new age of 214 ± 8 Ma falls within the Norian stage of the Triassic system.