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Oxygen isotope composition of the Denchai sapphire, Thailand: a clue to its enigmatic origin


Yui, TF and Zaw, K and Limtrakun, P, Oxygen isotope composition of the Denchai sapphire, Thailand: a clue to its enigmatic origin, Lithos, 67, (1-2) pp. 153-161. ISSN 0024-4937 (2003) [Refereed Article]

DOI: doi:10.1016/S0024-4937(02)00268-2


Alluvial gem sapphires from the Denchai area, northern Thailand, have O-isotope compositions ranging from +4.7‰ to +6.1‰ (15 samples), with one outlier, +8.4‰. It is suggested that these sapphires are not in O-isotope equilibrium with and must be xenocrysts from the nearby alkali basalts, which contain olivine phenocrysts with δ18O = +4.9‰ to +5.1‰ and are the presumed sources of these gem sapphires. Homogeneous δ18O values within individual sapphire crystal indicate limited interactions with the carrier magmas during transport to the surface. The O-isotope compositions of these sapphires suggest that crustal rocks might have been involved in the genesis of those sapphires with δ18O values higher than +5.5‰. A hybrid origin model for the Denchai sapphires is, therefore, postulated, which involves different degrees of interactions between a fractionated partial melt from (metasomatized) mantle and a lower/mid-crust Al-rich rock. © 2002 Elsevier Science B.V. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geology
Research Field:Igneous and metamorphic petrology
Objective Division:Mineral Resources (Excl. Energy Resources)
Objective Group:Other mineral resources (excl. energy resources)
Objective Field:Other mineral resources (excl. energy resources) not elsewhere classified
UTAS Author:Zaw, K (Professor Khin Zaw)
UTAS Author:Limtrakun, P (Mr Phisit Limtrakun)
ID Code:28049
Year Published:2003
Web of Science® Times Cited:30
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2003-08-01
Last Modified:2004-03-19

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