Discovery of the Early Paleozoic post-collisional granite in Altay, China and its geological significance

作者：Li HuiJun^*; He GuoQi; Wu TaiRan; Wu Bo

来源：Acta Petrologica Sinica, 2010, 26(8): 2445-2451.

• Post-collisional granite
• SHRIMP U-Pb dating
• Geochemistry
• Altay
• Xinjiang

Baihaba intrusion, located in Habahe County, Xinjiang Province, is mainly composed of biotite plagiogranite, and minor granodiorite. Baihaba rocks with higher SiO(2) and K(2)O contents can be classified as high-K calc-alkaline series rock and considered as weakly per-aluminous rocks ( SiO(2): 65. 58% similar to 65. 79%, Na(2)O/CaO: 1. 73 similar to 3. 43, Shand index <= 1. 05). The intrusion is characterized by high REE abundance(Sigma REE =174. 1 x 10(-6) similar to 210. 6 x 10(-6)), strong negative Eu anomalies (delta Eu =0. 54 similar to 0. 63), medium REE fractionation [(La/Yb)(N) = 4. 46 similar to 5. 56], enrichments in Rb, Th, U, K, La, Ce, Nd, Hf, Zr and Sm, but strong depletions of Ba, Nb, Ta, Sr, P and Ti. These characteristics of major, REE and trace elements indicate that the intrusion was formed in a transitional tectonic setting from compression to extensional regime, which can be classified as post-collisional granitoids. SHRIMP U-Pb zircon analyses yield ages of 413. 8 +/- 6. 4Ma. The discovery of Early Paleozoic post-collisional granites in Altay supports the presence of Altay-Mongolia microcontinent.

• 出版日期2010-8
• 单位北京大学; 中国地质科学院地质力学研究所