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

Jourdan, F., Hodges, K., Sell, B., Schaltegger, U., Wingate, M. T. D., Evins, L. Z., Soderlund, U., Haines, P. W., Phillips, D. and Blenkinsop, T. ORCID: https://orcid.org/0000-0001-9684-0749 2014. High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early-Middle Cambrian (Stage 4-5) extinction. Geology 42 (6) , pp. 543-546. 10.1130/G35434.1

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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 first 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 significant 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.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Subjects:	Q Science > QE Geology
Publisher:	Geological Society of America
ISSN:	0091-7613
Date of First Compliant Deposit:	30 March 2016
Date of Acceptance:	28 March 2014
Last Modified:	10 Nov 2023 10:14
URI:	https://orca.cardiff.ac.uk/id/eprint/83402

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