A tephrochronologic method based on apatite trace-element chemistry

Bryan Keith Sell, Scott Douglas Samson

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Geochemical correlation of ash-fall beds with conventional tephrochronologic methods is not feasible when original glass composition is altered. Thus, alternative correlation methods may be required. Initial studies of heavily altered Paleozoic tephra (K-bentonites) have suggested the potential for employing trace-element concentrations in apatite as ash-fall bed discriminators. To further test the utility of apatite trace-element tephrochronology, we analyzed apatite phenocrysts from unaltered volcanic rocks with an electron microprobe: nine samples from rocks erupted during the Quaternary and one sample from a rock erupted during the Paleogene. The resulting apatite trace-element data provide unique bed discriminators despite within-crystal variability. Each of the volcanic rocks studied possesses unique trends in Mg, Cl, Mn, Fe, Ce and Y concentrations in apatite. The results from this study establish an important tephrochronologic method that can be applied to nearly all portions of the Phanerozoic stratigraphic record and greatly assist development of an advanced timescale. In addition to establishing a fingerprint for a particular eruption, apatite chemistry provides useful information about the source magma.

Original languageEnglish (US)
Pages (from-to)157-166
Number of pages10
JournalQuaternary Research
Issue number1
StatePublished - Jul 2011


  • Apatite
  • Bentonite
  • Electron microprobe
  • Tephrochronology
  • Trace elements

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Earth-Surface Processes
  • General Earth and Planetary Sciences


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