A late Triassic impact ejecta layer in southwestern Britain

Gordon Mark Walkden, Julian Parker, S. Kelley

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Despite the 160 or so known terrestrial impact craters of Phanerozoic age, equivalent ejecta deposits within distal sedimentary successions are rare. We report a Triassic deposit in southwestern Britain that contains spherules and shocked quartz, characteristic of an impact ejecta layer. Inter- and intragranular potassium feldspar from the deposit yields an argon-argon age of 214 +/- 2.5 million years old. This is within the age range of several known Triassic impact craters, the two closest of which, both in age and location, are Manicouagan in northeastern Canada and Rochechouart in central France. The ejecta deposit provides an important sedimentary record of an extraterrestrial impact in the Mesozoic that will help to decipher the number and effect of impact events, the source and dynamics of the event that left this distinctive sedimentary marker, and the relation of this ejecta layer to the timing of extinctions in the fossil record.

Original languageEnglish
Pages (from-to)2185-2188
Number of pages3
JournalScience
Volume298
Issue number5601
DOIs
Publication statusPublished - Dec 2002

Keywords

  • MASS EXTINCTION
  • MICROTEKTITES
  • TEKTITES
  • DEPOSITS
  • HAITI

Cite this

A late Triassic impact ejecta layer in southwestern Britain. / Walkden, Gordon Mark; Parker, Julian; Kelley, S.

In: Science, Vol. 298, No. 5601, 12.2002, p. 2185-2188.

Research output: Contribution to journalArticle

Walkden, Gordon Mark ; Parker, Julian ; Kelley, S. / A late Triassic impact ejecta layer in southwestern Britain. In: Science. 2002 ; Vol. 298, No. 5601. pp. 2185-2188.
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