Gem-corundum megacrysts from east Australian basalt fields: trace elements, oxygen isotopes and origins

Sutherland, F.L., Zaw, K., Meffre, S., Giuliani, G., Fallick, A.E., Graham, I.T. and Webb, G.B. (2009) Gem-corundum megacrysts from east Australian basalt fields: trace elements, oxygen isotopes and origins. Australian Journal of Earth Sciences, 56(7), pp. 1003-1022. (doi: 10.1080/08120090903112109)

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Publisher's URL: http://dx.doi.org/10.1080/08120090903112109

Abstract

Gem corundum, a minor but persisten megacryst in east Australian basalt fields, is mined from some placer concentrations. Laser ablation, inductively couled plasma mass spectrometry analyses and O isotope determinations on a colour range of corundum from different fields, show that chromophore (Fe, Cr, Ti, V) and genetic indicator (Ga, Mg, δ18O) values can distinguish corundum sources (magmatic, metamorphic and metasomatic) before basalt incorporation. They also characterise corundum groups from different fields. This identified two metamorphic groups, one carrying ruby at Barrington Tops, and a magmatic group distinct from those from other gem fields (lower Fe, northeast Tasmania; higher Fe, Yarrowitch). Ruby-bearing groups show clear provincial characteristics and include lower temperature spinel-facies groups (Barrington, Yarrowitch) and higher temperature garnet-facies groups (Cudgegong-Macquarie River). High Mg/Fe and Ni values in the latter approach those for corundum in diamond, and are a possible diamond indicator. The corundum derived from diverse fold-belt and felsic sources in underlying lithosphere forms a dataset for comparing corundum for other basalt fields.

Item Type:Articles
Keywords:Australia, basalt fields, gem corundum, LA-ICP-MS, oxygen isotopes, ruby, sapphire
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Fallick, Professor Anthony
Authors: Sutherland, F.L., Zaw, K., Meffre, S., Giuliani, G., Fallick, A.E., Graham, I.T., and Webb, G.B.
Subjects:Q Science > QE Geology
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Australian Journal of Earth Sciences
Publisher:Geological Society of Australia
ISSN:0812-0099
ISSN (Online):1440-0952

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