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An unusual sapphire–zircon–magnetite xenolith from the Chanthaburi Gem Province, Thailand

Published online by Cambridge University Press:  05 July 2018

Robert R. Coenraads ,
Pongsak Vichit  and
F. Lin Sutherland
Robert R. Coenraads
Affiliation:
The Gemmological Association of Australia, Gemmology House, 24 Wentworth Ave, Sydney, N.S.W. 2000, Australia
Pongsak Vichit
Affiliation:
Economic Geology Division, Department of Mineral Resources, Rama 6 Road, Bangkok 10400, Thailand
F. Lin Sutherland
Affiliation:
Division of Earth and Environmental Sciences, The Australian Museum, 6-8 College Street, Sydney, N.S.W. 2000, Australia
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Abstract

A sapphire, zircon and magnetite-bearing xenolith from Khao Wua, near Chanthaburi in Thailand, conclusively demonstrates a common origin for the sapphire, zircon and magnetite found in alluvial deposits in the Chanthaburi gem fields. The original aluminium- and titanium-rich octahedral magnetite crystal in the xenolith exsolved into hercynite, magnetite and hematite during cooling. It includes minor anhedral jarosite–alunite, possibly originating as an iron-sulphide-rich immiscible liquid. Uranium-lead isotope dating of zircon in the xenolith gives an age of 1–2 (± <1) million years (Ma). This falls within fission track ages for alluvial zircons (2.57 ± 0.20 Ma) from the Chanthaburi—Trat gem fields and within the potassium-argon ages of 0.44 to 3.0 Ma for the alkali basaltic volcanism in the Chanthaburi Province. These data suggest a common origin for sapphire, zircon and magnetite, and link them with the processes involved in alkali basaltic magma generation. The high iron and zirconium, low magnesium, and the inferred sulphides suggest pegmatite-like crystallization in an incompatible-element enriched, silica-poor magma (partial melt or fractionation product) in the deep crust or upper mantle. Etch features on exposed surfaces of the xenolith indicate that it was transported out of its equilibrium environment by the rise of later magma.

Keywords

sapphirezirconuranium-lead datingxenolithKhao WuaChanthaburiThailand
Type
Mineralogy
Information
Mineralogical Magazine , Volume 59 , Issue 396 , September 1995 , pp. 465 - 479
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1995

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References

Aranyakanon, P., Sampatavanija, S. and Ruengsuwan, J. (1970) Report on gem deposits at Si Sa Kef. A report by the Econ. Geol. Div., Dept. Min. Res., Bangkok, Thailand (in Thai); 12 pp.Google Scholar
Barr, S.M. and Dostal, J. (1986) Petrochemistry and origin of megacrysts in Upper Cenozoic basalts, Thailand. J. SE. Asian Earth Sci., 1, 107–16.CrossRefGoogle Scholar
Barr, S.M. and James, D.E. (1990) Trace element characteristics of Upper Cenozoic basaltic rocks of Thailand, Kampuchea and Vietnam. J. SE. Asian Earth Sci, 4, 233–42.CrossRefGoogle Scholar
Barr, S.M. and MacDonald, A.S. (1978) Geochemistry and petrogenesis of late Cenozoic alkaline basalts of Thailand. Bull. Geol. Soc. Malaysia, 10, 21–48.Google Scholar
Barr, S.M. and MacDonald, A.S. (1979) Palaeomagnet-ism, age, and geochemistry of the Denchai basalt, northern Thailand. Earth Planet. Sci. Lett., 46, 113–24.CrossRefGoogle Scholar
Barr, S.M. and MacDonald, A.S. (1981) Geochemistry and geochronology of late Cenozoic basalts of Southeast Asia,. Geol. Soc. Amer. Bull., 92, 1069–142.CrossRefGoogle Scholar
Best, M.G. and Brimhall, W.H. (1974) Late Cenozoic alkalic basaltic magmas in the Western Colorado Plateau and the Basin and Range Transition Zone U.S.A., and their bearing on mantle dynamics. Geol. Soc. Amer. Bull., 85, 1677–90.2.0.CO;2>CrossRefGoogle Scholar
Carbonnel, J.P., Selo, M. and Poupeau, G. (1973) Fission track age of the gem deposits of Pailin (Cambodia) and recent tectonics in the Indochinan Province. Modern Geology, 4, 61–4.Google Scholar
Charaljavanaphet, J. (1951) Gem deposits at Bo Na-Wong, Tok-Phrom, Bo-Rai in Chanthaburi and Trat Provinces and Bo Phloi in Kanchanaburi Province in Geologic Reconnaissance of the Mineral Deposits of Thailand. U.S. Geol. Surv. Bull., 984, 148–50.Google Scholar
Charusiri, P., Clark, A.H. and Farrar, E. (in prep.) Ar40/Ar39 geochronology of some Thai basalts. J. SE. Asian Earth Sci., Coenraads, R.R. (1990) Key areas for alluvial diamond and sapphire exploration in the New England gem fields, New South Wales, Australia. Econ. Geol., 85, 1186–207.Google Scholar
Coenraads, R.R. (1992a) Sapphires and rubies asso-ciated with volcanic provinces: Inclusions and surface features shed light on their origin. Austral. Gemmol., 18, 70–78.Google Scholar
Coenraads, R.R. (19926) Surface Features of Natural Rubies and Sapphires associated with Volcanic Provinces. J. Gemmol, 23, 3, 151-60.Google Scholar
Coenraads, R.R., Sutherland, F.L. and Kinny, P.D. (1990) The Origin of Sapphires: U-Pb dating of zircon inclusions sheds new light. Mineral. Mag., 54, 113–22.CrossRefGoogle Scholar
Coombs, D.S. and Wilkinson, J.F.G. (1969) Lineages and fractionation trends in undersaturated volcanic rocks from the East Otago volcanic province (New Zealand) and related rocks. J. Petrol., 10, 440–501.CrossRefGoogle Scholar
Guo, J.F. (1993) Lead diffusion in zircon and its significance to U-Pb geochronology, 1993 Interna-tional Association of Volcanology and Chemistry of the Earths Interior General Assembly, Abstracts. IAVCEI, Canberra, Australia, p. 43.Google Scholar
Guo, J., Griffin, W.L. and O'Reilly S.Y. (1994) A cobalt-rich spinel inclusion in a sapphire from Bo Ploi, Thailand. Mineral. Mag., 58, 247–58.CrossRefGoogle Scholar
Irving, A.J. (1986) Polybaric magma mixing in alkaline basalts and kimberlites: evidence from corundum, zircon and ilmenite megacrysts. Ceol. Soc. Austral. Abstr. Ser. 16, 263–4.Google Scholar
Jungyusuk, N. and Sirinawin, T. (1983) Cenozoic basalts of Thailand: A paper presented at the Conference on geology and mineral resources of Thailand, Dept. Miner. Res., Bangkok, Thailand, 19-28 Nov., 1983, 9 pp.Google Scholar
Kinny, P.D. (1993) Kimberlite-erupted mantle zircons: Keys to mantle processes past and present. 1993 International Association of Volcanology and Chemistry of the Earths Interior General Assembly, Abstracts. IAVCEI, Canberra, Australia, p. 58.Google Scholar
Robertson, A.D. and Sutherland, F.L. (1992) Possible origins and ages for sapphire and diamonds from the Central Queensland gemfields. In R.O. Chalmers, Commemorative Papers (Mineralogy, Meteorites, Geology). (Ed.) Sutherland, L., Rec. Austral. Museum Suppl. 15, 45–54.CrossRefGoogle Scholar
Salyaphongse, S. and Jungyusuk, N. (1983) Geological Map of Thailand 1:500,000; Central and Eastern Sheet: Published by the Geol. Surv. Div., Dept. Min. Res., Bangkok, Thailand. Sirinawin, T. (1981) Geochemistry and genetic significance of gem-bearing basalt in Chanthaburi-Trat area: Unpubl. Thesis, Dept. Geological Sciences, Chiangmai University, (in Thai with English abstract), 87 pp.Google Scholar
Sivabovorn, V., Paichitprapaporn, V. and Tansatein, S. (1976) Geology of Phratabong-Chanthaburi (Sheet ND 48-9, ND 48-13): A report of Geol. Surv. Div., Dept. Min. Res., Bangkok, Thailand, (in Thai), 51 pp.Google Scholar
Stephenson, P.J. (1990) The geological context of sapphire occurrences in the Anakie region, central Queensland. Geol. Soc. Austral. Abstr. Ser, 25, 232–3.Google Scholar
Sutherland, F.L. and Coenraads, R.R. (in prep) Ruby-sapphirine-sapphire-spinel xenoliths from Barrington Tops, N.S.W. Sutherland, F.L. and Kinny, P.D. (1990) Ion probe U/Pb isotopic ages of gemmy zircons from eastern Australia, including Tasmania. Geol. Soc. Austral. Abstr. Ser., 25, 241–2.Google Scholar
Taylor, G.C. Jr. and Buravas, S. (1951) Gem deposits at Khao Ploi Waen and Bang Ka Cha, Chanthaburi Province in Geologic Reconnaissance of the Mineral Deposits of Thailand. U.S. Geol. Surv. Bull., 984, 144–8.Google Scholar
Turnock, A.C. and Eugster, H.P. (1962) Fe-Al Oxides: Phase relations below 1000°C. J. Petrol., 3, 533–5.CrossRefGoogle Scholar
Upton, B.J.G., Aspin, P. and Champman, N.A. (1983) The upper mantle and deep crust beneath the British Isles: evidence from inclusions in volcanic rocks. J. Geol. Soc. London, 140, 105–21.CrossRefGoogle Scholar
Vichit, P. (1987) Gemstones in Thailand. J. Geol. Soc. Thailand, 9, 108–33.Google Scholar
Vichit, P. (1992) Gemstones in Thailand: Proceedings of the National Conference on ‘Geologic Resources of Thailand: Potential for Future Development', Supplementary Volume, 17-24 Nov., 1992. Published by the Department of Mineral Resources, Bangkok, Piencharoen, Thailand C. (ed. in chief), p. 124-50.Google Scholar
Vichit, P., Vudhichativanich, S. and Hansawek, R. (1978) The distribution and some characteristics of corundum-bearing basalts in Thailand. J. Geol. Soc. Thailand, Special Issue for III GEOSEA, 3, M4-1-M4-38.Google Scholar
Yaemniyom, N. (1982) The Petrochemical Study of Corundum-Bearing Basalts at Bo Phloi District, Kanchanaburi. Unpubl. M.Sc. Thesis, Dept of Geology, Chulalongkorn University, Thailand, 100 pp.Google Scholar