40Ar/39Ar constraints on the timing and origin of Miocene leucitite volcanism in southeastern Australia

Cohen, B.E. , Knesel, K.M., Vasconcelos, P.M., Thiede, D.S. and Hergt, J.M. (2008) 40Ar/39Ar constraints on the timing and origin of Miocene leucitite volcanism in southeastern Australia. Australian Journal of Earth Sciences, 55(3), pp. 407-418. (doi: 10.1080/08120090701769514)

Abstract

Laser incremental-heating 40Ar/39Ar geochronology of seven leucitites from southeastern Australia indicates that leucite-bearing lavas in individual geographic clusters were erupted in one million years or less. The eruption ages range from 17.9 ± 0.3 Ma (2σ) at El Capitan in northern-central New South Wales to 8.9 ± 0.2 Ma (2σ) at Cosgrove in northern Victoria. The 40Ar/39Ar results demonstrate that the southward migration of leucite-bearing lavas was near-contemporaneous with age-progressive central-volcano magmatism in southeastern Australia. As such, the 40Ar/39Ar results are consistent with a hotspot-related origin for the leucitites. However, the question of whether single or multiple hotspots are required to explain these volcanic chains, which are separated by a distance of about 300 km, awaits a more complete geochronological picture of the onset, duration and migration of leucitite and central-volcano magmatism in eastern Australia.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cohen, Dr Benjamin
• Authors: Cohen, B.E., Knesel, K.M., Vasconcelos, P.M., Thiede, D.S., and Hergt, J.M.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Australian Journal of Earth Sciences
• Publisher: Geological Society of Australia
• ISSN: 0812-0099
• ISSN (Online): 1440-0952