High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early-Middle Cambrian (Stage 4-5) extinction

F. Jourdan, K. Hodges, B. Sell, U. Schaltegger, M. T. D. Wingate, L. Z. Evins, U. Söderlund, P. W. Haines, D. Phillips, Thomas Blenkinsop

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

The voluminous Kalkarindji flood basalts erupted in Australia during the Cambrian and covered >2 × 106 km2. New U-Pb and 40Ar/39Ar age data from intrusive rocks and lava flows yielded statistically indistinguishable ages at ca. 511 Ma, suggesting a relatively brief emplacement for this province. A zircon age of 510.7 ± 0.6 Ma shows that this province is temporally indistinguishable at the few-hundred-thousand-year level from the Early-Middle Cambrian (Stage 4-5) boundary age of 510 ± 1 Ma, which marks the fi rst severe extinction of the Phanerozoic and an extended marine anoxia period. Sulfur concentration measurements ranging from <50 to 1900μg/g, and fractal analysis of extensive explosive volcanic breccias, suggest that blasts and phreatomagmatic explosions have contributed to injection of large amounts of sulfur into the stratosphere. In addition, magma intrusions in oil, gas, and sulfate deposits may have generated signifi cant emission of CH4 and SO2 which, along with volcanic gases, would have combined to cause an oscillation of the climate and led to the Cambrian extinction.

Original languageEnglish
Pages (from-to)543-546
Number of pages4
JournalGeology
Volume42
Issue number6
DOIs
Publication statusPublished - 2014
Externally publishedYes

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