Oxygen isotope studies on placer sapphire and ruby in the Chanthaburi-Trat alkali basaltic gemfield, Thailand
Placer sapphire and ruby are common in the western zone and the central/ eastern zone, respectively, of the Chanthaburi-Trat (C-T) alkali basaltic gemfield in southeastern Thailand. Sapphires have O-isotope composition in the range from +5.1‰ to +6.2‰, while rubies, from +1.3‰ to +4.2‰. These data c...
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th-cmuir.6653943832-616362018-09-11T08:56:18Z Oxygen isotope studies on placer sapphire and ruby in the Chanthaburi-Trat alkali basaltic gemfield, Thailand Tzen Fu Yui Chao Ming Wu Phisit Limtrakun Weerapan Sricharn Apichet Boonsoong Earth and Planetary Sciences Placer sapphire and ruby are common in the western zone and the central/ eastern zone, respectively, of the Chanthaburi-Trat (C-T) alkali basaltic gemfield in southeastern Thailand. Sapphires have O-isotope composition in the range from +5.1‰ to +6.2‰, while rubies, from +1.3‰ to +4.2‰. These data clearly show that the C-T placer sapphires and rubies should have a different primary genesis. Olivine in the nearby alkali basalts exhibits a narrow range of O-isotope composition, i.e., from +4.8‰ to +5.0‰, demonstrating that the C-T placer gem corundums cannot be phenocrysts of these basalts. The homogeneous O-isotope compositions of sapphires, combined with other available data, strongly suggest that these sapphires most probably have originally crystallized from evolved mantle magmas at lower crust/upper mantle depths. The varied O-isotope compositions of rubies are consistent with the previous suggestion that these rubies originally formed in mafic metamorphic rocks under upper mantle conditions, although the O-isotope data also require that the mafic rocks would have experienced an earlier surface (sea) water-rock interaction history. Consistent with the available data, a suggestion with garnet pyroxenite in the sub-continental mantle as the primary source for these placer gem corundums is tentatively proposed. The surface distribution of sapphire or ruby in the studied area may be a sign of composition variation of garnet pyroxenite underneath. © 2005 Elsevier B.V. All rights reserved. 2018-09-11T08:56:18Z 2018-09-11T08:56:18Z 2006-02-01 Journal 00244937 2-s2.0-30944448620 10.1016/j.lithos.2005.06.002 https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=30944448620&origin=inward http://cmuir.cmu.ac.th/jspui/handle/6653943832/61636 |
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Earth and Planetary Sciences Tzen Fu Yui Chao Ming Wu Phisit Limtrakun Weerapan Sricharn Apichet Boonsoong Oxygen isotope studies on placer sapphire and ruby in the Chanthaburi-Trat alkali basaltic gemfield, Thailand |
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Placer sapphire and ruby are common in the western zone and the central/ eastern zone, respectively, of the Chanthaburi-Trat (C-T) alkali basaltic gemfield in southeastern Thailand. Sapphires have O-isotope composition in the range from +5.1‰ to +6.2‰, while rubies, from +1.3‰ to +4.2‰. These data clearly show that the C-T placer sapphires and rubies should have a different primary genesis. Olivine in the nearby alkali basalts exhibits a narrow range of O-isotope composition, i.e., from +4.8‰ to +5.0‰, demonstrating that the C-T placer gem corundums cannot be phenocrysts of these basalts. The homogeneous O-isotope compositions of sapphires, combined with other available data, strongly suggest that these sapphires most probably have originally crystallized from evolved mantle magmas at lower crust/upper mantle depths. The varied O-isotope compositions of rubies are consistent with the previous suggestion that these rubies originally formed in mafic metamorphic rocks under upper mantle conditions, although the O-isotope data also require that the mafic rocks would have experienced an earlier surface (sea) water-rock interaction history. Consistent with the available data, a suggestion with garnet pyroxenite in the sub-continental mantle as the primary source for these placer gem corundums is tentatively proposed. The surface distribution of sapphire or ruby in the studied area may be a sign of composition variation of garnet pyroxenite underneath. © 2005 Elsevier B.V. All rights reserved. |
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Tzen Fu Yui Chao Ming Wu Phisit Limtrakun Weerapan Sricharn Apichet Boonsoong |
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Tzen Fu Yui Chao Ming Wu Phisit Limtrakun Weerapan Sricharn Apichet Boonsoong |
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Tzen Fu Yui |
title |
Oxygen isotope studies on placer sapphire and ruby in the Chanthaburi-Trat alkali basaltic gemfield, Thailand |
title_short |
Oxygen isotope studies on placer sapphire and ruby in the Chanthaburi-Trat alkali basaltic gemfield, Thailand |
title_full |
Oxygen isotope studies on placer sapphire and ruby in the Chanthaburi-Trat alkali basaltic gemfield, Thailand |
title_fullStr |
Oxygen isotope studies on placer sapphire and ruby in the Chanthaburi-Trat alkali basaltic gemfield, Thailand |
title_full_unstemmed |
Oxygen isotope studies on placer sapphire and ruby in the Chanthaburi-Trat alkali basaltic gemfield, Thailand |
title_sort |
oxygen isotope studies on placer sapphire and ruby in the chanthaburi-trat alkali basaltic gemfield, thailand |
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2018 |
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https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=30944448620&origin=inward http://cmuir.cmu.ac.th/jspui/handle/6653943832/61636 |
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