en
Scientific article
English

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

Published inGeology, vol. 42, no. 6, p. 543-546
Publication date2014
Abstract

The voluminous Kalkarindji fl ood 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 fl ows 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 1900 μg/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.

Keywords
  • Kalkarindji
  • Large igneous province
  • Cambrian
  • Mass extinction
  • U-Pb dating
  • Zircon
  • Baddeleyite
Citation (ISO format)
JOURDAN, F. et al. High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early-Middle Cambrian (Stage 4-5) extinction. In: Geology, 2014, vol. 42, n° 6, p. 543–546. doi: 10.1130/G35434.1
Main files (1)
Article (Published version)
accessLevelRestricted
Identifiers
ISSN of the journal0091-7613
460views
0downloads

Technical informations

Creation06/17/2014 11:00:00 AM
First validation06/17/2014 11:00:00 AM
Update time03/14/2023 9:21:52 PM
Status update03/14/2023 9:21:52 PM
Last indexation05/02/2024 3:20:37 PM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack