Abstract
Gem-quality zircon megacrysts occur in placer deposits in the Central Highlands, Vietnam, and have euhedral to anhedral crystal shapes with dimensions of ~3 cm in length. These zircons have primary inclusions of calcite, olivine, and corundum. Secondary quartz, baddeleyite, hematite, and CO 2 fluid inclusions were found in close proximity to cracks and tubular channels. LA-ICP-MS U-Pb ages of analyzed zircon samples yielded two age populations of ca. 1.0 Ma and ca. 6.5 Ma, that were consistent with the ages of alkali basalt eruptions in the Central Highlands at Buon Ma Thuot (5.80–1.67 Ma), Pleiku (4.30–0.80 Ma), and Xuan Loc (0.83–0.44 Ma). The zircon geochemical signatures and primary inclusions suggested a genesis from carbonatite-dominant melts as a result of partial melting of a metasomatized lithospheric mantle source, but not from the host alkali basalt. Chondrite-normalized rare earth element patterns showed a pronounced positive Ce, but negligible Eu anomalies. Detailed hyperspectral Dy 3+ photoluminescence images of zircon megacrysts revealed resorption and re-growth processes.
| Original language | English |
|---|---|
| Article number | 89 |
| Journal | Minerals |
| Volume | 9 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Jan 1 2019 |
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All Science Journal Classification (ASJC) codes
- Geotechnical Engineering and Engineering Geology
- Geology
Cite this
Gem-quality zircon megacrysts from placer deposits in the central highlands, Vietnam—potential source and links to cenozoic alkali basalts. / Sinh, Vuong Bui Thi; Osanai, Yasuhito; Lenz, Christoph; Nakano, Nobuhiko; Adachi, Tatsuro; Belousova, Elena; Kitano, Ippei.
In: Minerals, Vol. 9, No. 2, 89, 01.01.2019.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Gem-quality zircon megacrysts from placer deposits in the central highlands, Vietnam—potential source and links to cenozoic alkali basalts
AU - Sinh, Vuong Bui Thi
AU - Osanai, Yasuhito
AU - Lenz, Christoph
AU - Nakano, Nobuhiko
AU - Adachi, Tatsuro
AU - Belousova, Elena
AU - Kitano, Ippei
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Gem-quality zircon megacrysts occur in placer deposits in the Central Highlands, Vietnam, and have euhedral to anhedral crystal shapes with dimensions of ~3 cm in length. These zircons have primary inclusions of calcite, olivine, and corundum. Secondary quartz, baddeleyite, hematite, and CO 2 fluid inclusions were found in close proximity to cracks and tubular channels. LA-ICP-MS U-Pb ages of analyzed zircon samples yielded two age populations of ca. 1.0 Ma and ca. 6.5 Ma, that were consistent with the ages of alkali basalt eruptions in the Central Highlands at Buon Ma Thuot (5.80–1.67 Ma), Pleiku (4.30–0.80 Ma), and Xuan Loc (0.83–0.44 Ma). The zircon geochemical signatures and primary inclusions suggested a genesis from carbonatite-dominant melts as a result of partial melting of a metasomatized lithospheric mantle source, but not from the host alkali basalt. Chondrite-normalized rare earth element patterns showed a pronounced positive Ce, but negligible Eu anomalies. Detailed hyperspectral Dy 3+ photoluminescence images of zircon megacrysts revealed resorption and re-growth processes.
AB - Gem-quality zircon megacrysts occur in placer deposits in the Central Highlands, Vietnam, and have euhedral to anhedral crystal shapes with dimensions of ~3 cm in length. These zircons have primary inclusions of calcite, olivine, and corundum. Secondary quartz, baddeleyite, hematite, and CO 2 fluid inclusions were found in close proximity to cracks and tubular channels. LA-ICP-MS U-Pb ages of analyzed zircon samples yielded two age populations of ca. 1.0 Ma and ca. 6.5 Ma, that were consistent with the ages of alkali basalt eruptions in the Central Highlands at Buon Ma Thuot (5.80–1.67 Ma), Pleiku (4.30–0.80 Ma), and Xuan Loc (0.83–0.44 Ma). The zircon geochemical signatures and primary inclusions suggested a genesis from carbonatite-dominant melts as a result of partial melting of a metasomatized lithospheric mantle source, but not from the host alkali basalt. Chondrite-normalized rare earth element patterns showed a pronounced positive Ce, but negligible Eu anomalies. Detailed hyperspectral Dy 3+ photoluminescence images of zircon megacrysts revealed resorption and re-growth processes.
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U2 - 10.3390/min9020089
DO - 10.3390/min9020089
M3 - Article
AN - SCOPUS:85062345443
VL - 9
JO - Minerals
JF - Minerals
SN - 2075-163X
IS - 2
M1 - 89
ER -