An (U-Th)/He age for the shallow-marine Wetumpka impact structure, Alabama, USA

Jo Anne Wartho, Matthijs Van Soest, David T. King, Lucille W. Petruny

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Single crystal (U-Th)/He dating was applied to 24 apatite and 23 zircon grains from the Wetumpka impact structure, Alabama, USA. This small approximately 5-7.6km impact crater was formed in a shallow marine environment, with no known preserved impact melt, thus offering a challenge to common geochronological techniques. A mean (U-Th)/He apatite and zircon age of 84.4±1.4Ma (2σ) was obtained, which is within error of the previously estimated Late Cretaceous impact age of approximately 83.5Ma. In addition, helium diffusion modeling of apatite and zircon grains during fireball/contact, shock metamorphism, and hydrothermal events was undertaken, to show the influence of these individual thermal processes on resetting (U-Th)/He ages in the Wetumpka samples. This study has shown that the (U-Th)/He geochronological technique has real potential for dating impact structures, especially smaller and eroded impact structures that lack impact melt lithologies.

Original languageEnglish (US)
Pages (from-to)1243-1255
Number of pages13
JournalMeteoritics and Planetary Science
Volume47
Issue number8
DOIs
StatePublished - Aug 1 2012

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impact structure
apatite
zircon
apatites
impact melts
melt
shock metamorphism
dating
resetting
helium
crater
marine environment
lithology
marine environments
fireballs
crystal
Cretaceous
craters
modeling
shock

ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science

Cite this

An (U-Th)/He age for the shallow-marine Wetumpka impact structure, Alabama, USA. / Wartho, Jo Anne; Van Soest, Matthijs; King, David T.; Petruny, Lucille W.

In: Meteoritics and Planetary Science, Vol. 47, No. 8, 01.08.2012, p. 1243-1255.

Research output: Contribution to journalArticle

Wartho, Jo Anne ; Van Soest, Matthijs ; King, David T. ; Petruny, Lucille W. / An (U-Th)/He age for the shallow-marine Wetumpka impact structure, Alabama, USA. In: Meteoritics and Planetary Science. 2012 ; Vol. 47, No. 8. pp. 1243-1255.
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