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<meta content="Zaw, K." name="eprints.creators_name" />
<meta content="Limtrakun, P." name="eprints.creators_name" />
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<meta content="Alluvial gem sapphires from the Denchai area, northern Thailand, have O-isotope compositions ranging from + 4.7 per mil to + 6.1 per mil(15 samples), with one outlier, + 8.4 per mil. 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 delta 18 O= + 4.9 per mil to + 5.1 per mil and are the presumed sources of these gem sapphires. Homogeneous delta 18 O 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 delta 18 O values higher than + 5.5 per mil. 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." name="eprints.abstract" />
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<meta content="Alluvial gem sapphires from the Denchai area, northern Thailand, have O-isotope compositions ranging from + 4.7 per mil to + 6.1 per mil(15 samples), with one outlier, + 8.4 per mil. 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 delta 18 O= + 4.9 per mil to + 5.1 per mil and are the presumed sources of these gem sapphires. Homogeneous delta 18 O 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 delta 18 O values higher than + 5.5 per mil. 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." name="DC.description" />
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<h1 class="ep_tm_pagetitle">Oxygen isotope composition of the Denchai sapphire, Thailand: a clue to its enigmatic origin</h1>
<p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Yui, Tzen-Fu</span> and <span class="person_name">Zaw, K.</span> and <span class="person_name">Limtrakun, P.</span> (2003) <xhtml:em>Oxygen isotope composition of the Denchai sapphire, Thailand: a clue to its enigmatic origin.</xhtml:em> Lithos, 67 . pp. 153-161. ISSN 0024-4937</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/1877/1/Tzen-Fu%2C_Zaw_et_al_LITHOS_2003.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/1877/1/Tzen-Fu%2C_Zaw_et_al_LITHOS_2003.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />173Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input accept-charset="utf-8" value="2360" name="docid" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://dx.doi.org/10.1016/S0024-4937(02)00268-2">http://dx.doi.org/10.1016/S0024-4937(02)00268-2</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">Alluvial gem sapphires from the Denchai area, northern Thailand, have O-isotope compositions ranging from + 4.7 per mil to + 6.1 per mil(15 samples), with one outlier, + 8.4 per mil. 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 delta 18 O= + 4.9 per mil to + 5.1 per mil and are the presumed sources of these gem sapphires. Homogeneous delta 18 O 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 delta 18 O values higher than + 5.5 per mil. 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.</p></div><table style="margin-bottom: 1em" cellpadding="3" class="not_ep_block" border="0"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">Gemfield; Sapphire; Oxygen isotope; Alkali basalt; Thailand</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/260100.html">260000 Earth Sciences > 260100 Geology</a></td></tr><tr><th valign="top" class="ep_row">Collections:</th><td valign="top" class="ep_row">UNSPECIFIED</td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">1877</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Mrs Katrina Keep</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">06 Sep 2007</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">30 Jan 2008 15:27</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=1877;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=1877">item control page</a></p>
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