| 新疆吉木乃县恰其海A型花岗岩的地球化学特征、年代学及构造意义 |
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| 关键词:western Junggar A-type granite alkali granite Permian post-collision |
| 基金项目:新疆国土资源厅地质调查项目(编号: XJQDZ2008-01, XJQDZ2008-03) |
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| Geochemical Characteristics, Geochronology and Tectonic Implications of A-type Granite from Qiaqihai Intrusion in Jeminay County, Xinjiang |
| Large-size alkali granites are distributed in the northern part of western Junggar, Xinjiang, belonging to early Permian. Rock types include moyite and quartz syenite. The Qiaqihai intrusion is one of these granites. The SiO2 content of Qiaqihai intrusion ranges from 66.83% to 68.44%, and the intrusion is also characterized by high content of Al (14.46%～15.41%) and alkali, rich K, depleted Na, and low MgO. Rittmann values vary between 4.47 and 4.61, whereas K2O/Na2O values between 1.10 and 1.25, and FeOt/MgO values between 4.06 and 7.85. The REE patterns are characterized by LREE enrichment and medium to strong negative Eu anomalies with obvi-ous fractionation between LREE and HREE. These geochemical characteristics suggest that the Qiaqihai intrusion formed in a post-collisional extensional tectonic environment and occurred earlier than the collision time of East Junggar. The trace element features suggest that this intrusion belongs to A2-type granite and was possibly influ-enced by subduction-related fluid metasomatism. A-type granite can provide important constraints for late Paleo-zoic crustal evolution in this region. |
| JIN Song,ZHANG Zhao-yi,CHEN Zhi-bin,YANG Hong-bin,YANG Jin-jing,KANG Gui-jun.2010.Geochemical Characteristics, Geochronology and Tectonic Implications of A-type Granite from Qiaqihai Intrusion in Jeminay County, Xinjiang[J].Acta Geoscientica Sinica,31(6):803-812. |
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