Abstract
U-Pb and Rb-Sr radiometric dating has been done on zircon samples and mineral concentrates, respectively, separated from psammitic schists of the Sangun metamorphic rocks in central Kyushu, Japan. Based on their shapes and colors, zircon grains were grouped into six. Rounded and short prismatic zircons define, independently of their colors, a common discordia with an upper intercept at 1.91 ± 0.04 Ga. Elongated zircons define another discordia with an upper intercept at 0.93 ± 0.06 Ga. A Rb-Sr internal isochron defined by the mineral concentrates gives an age of 197.7 ± 6.5 Ma, which represents the time of the Sangun metamorphism in central Kyushu. The U-Pb age of 1.91 Ga coincides with that of zircons from the Oki metamorphic rocks (1.96 ± 0.04 Ga: Yamashita and Yanagi, 1994). This and the great abundance of 1.91 Ga grains in the zircon populations seem to indicate a prominent plutonic activity at 1.9-2.0 Ga in the provenance common for the Sangun and Oki metamorphic rocks. The U-Pb ages of zircon from the Sangun metamorphic rocks indicate the episodic growth at 1.91 and 0.93 Ga of the East Asian continent close to the Japanese Islands.
| Original language | English |
|---|---|
| Pages (from-to) | 261-271 |
| Number of pages | 11 |
| Journal | GEOCHEMICAL JOURNAL |
| Volume | 30 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - Jan 1 1996 |
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All Science Journal Classification (ASJC) codes
- Geophysics
- Geochemistry and Petrology
Cite this
U-Pb dating of detrital zircons from the Sangun metamorphic rocks, Kyushu, Southwest Japan : An evidence for 1.9-2.0 Ga granite emplacement in the provenance. / Miyamoto, Tomoharu; Yanagi, Takeru.
In: GEOCHEMICAL JOURNAL, Vol. 30, No. 5, 01.01.1996, p. 261-271.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - U-Pb dating of detrital zircons from the Sangun metamorphic rocks, Kyushu, Southwest Japan
T2 - An evidence for 1.9-2.0 Ga granite emplacement in the provenance
AU - Miyamoto, Tomoharu
AU - Yanagi, Takeru
PY - 1996/1/1
Y1 - 1996/1/1
N2 - U-Pb and Rb-Sr radiometric dating has been done on zircon samples and mineral concentrates, respectively, separated from psammitic schists of the Sangun metamorphic rocks in central Kyushu, Japan. Based on their shapes and colors, zircon grains were grouped into six. Rounded and short prismatic zircons define, independently of their colors, a common discordia with an upper intercept at 1.91 ± 0.04 Ga. Elongated zircons define another discordia with an upper intercept at 0.93 ± 0.06 Ga. A Rb-Sr internal isochron defined by the mineral concentrates gives an age of 197.7 ± 6.5 Ma, which represents the time of the Sangun metamorphism in central Kyushu. The U-Pb age of 1.91 Ga coincides with that of zircons from the Oki metamorphic rocks (1.96 ± 0.04 Ga: Yamashita and Yanagi, 1994). This and the great abundance of 1.91 Ga grains in the zircon populations seem to indicate a prominent plutonic activity at 1.9-2.0 Ga in the provenance common for the Sangun and Oki metamorphic rocks. The U-Pb ages of zircon from the Sangun metamorphic rocks indicate the episodic growth at 1.91 and 0.93 Ga of the East Asian continent close to the Japanese Islands.
AB - U-Pb and Rb-Sr radiometric dating has been done on zircon samples and mineral concentrates, respectively, separated from psammitic schists of the Sangun metamorphic rocks in central Kyushu, Japan. Based on their shapes and colors, zircon grains were grouped into six. Rounded and short prismatic zircons define, independently of their colors, a common discordia with an upper intercept at 1.91 ± 0.04 Ga. Elongated zircons define another discordia with an upper intercept at 0.93 ± 0.06 Ga. A Rb-Sr internal isochron defined by the mineral concentrates gives an age of 197.7 ± 6.5 Ma, which represents the time of the Sangun metamorphism in central Kyushu. The U-Pb age of 1.91 Ga coincides with that of zircons from the Oki metamorphic rocks (1.96 ± 0.04 Ga: Yamashita and Yanagi, 1994). This and the great abundance of 1.91 Ga grains in the zircon populations seem to indicate a prominent plutonic activity at 1.9-2.0 Ga in the provenance common for the Sangun and Oki metamorphic rocks. The U-Pb ages of zircon from the Sangun metamorphic rocks indicate the episodic growth at 1.91 and 0.93 Ga of the East Asian continent close to the Japanese Islands.
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U2 - 10.2343/geochemj.30.261
DO - 10.2343/geochemj.30.261
M3 - Article
AN - SCOPUS:0030439744
VL - 30
SP - 261
EP - 271
JO - Geochemical Journal
JF - Geochemical Journal
SN - 0016-7002
IS - 5
ER -