Sutherland F. L., Zaw K., Meffre S., Giuliani Gaston, Fallick A. E., Graham I. T., 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), p. 1003-1022. ISSN 0812-0099.
Titre du document
Gem-corundum megacrysts from east Australian basalt fields : trace elements, oxygen isotopes and origins
Année de publication
Sutherland F. L., Zaw K., Meffre S., Giuliani Gaston, Fallick A. E., Graham I. T., Webb G. B.
Australian Journal of Earth Sciences, 2009,
56 (7), p. 1003-1022 ISSN 0812-0099
Gem corundum, a minor but persistent megacryst in east Australian basalt fields, is mined from some placer concentrations. Laser ablation, inductively coupled 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, 18O) 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 from other basalt fields.
Plan de classement
Géologie et formations superficielles