| 内蒙古东七一山花岗岩地球化学、锆石SHRIMP U-Pb年龄及岩体形成环境探讨 |
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| 关键词:granite rock geochemistry zircon U-Pb dating collision orogenesis Hercynian orogeny Beishan |
| 基金项目:国家自然科学基金项目(编号: 41040019);国家科技支撑计划(编号: 2006BAB01A09) |
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| Geochemistry, SHRIMP Zircon U-Pb Dating and Formation Environment of Dongqiyishan Granite, Inner Mongolia |
| During Paleozoic, the crustal movement was intense in Beishan area, which mainly found expression in the splitting of Early Palaeozoic unified continent and the formation of ocean basin in Middle Ordovician. At the end of Silurian, the oceanic basin was underthrusting in SN direction and was finally closed, that caused the collage between the northern side of the Kazakhstan plate and the southern Tarim plate as well as the formation of a relatively uniform plate. In Late Paleozoic, another movement occurred. From Carboniferous to Permian, the acid-intermediate magmatic intrusions in these areas made up important geological events. The outcropped area of granite occupies 1/3 of the total area. Nevertheless, researchers tend to ignore the crustal movement, especially the intrusion of granitic magma in Devonian period. The authors hold that the volcano-sedimentary and tectonic activities did occur in Devonian, so there existed strong magmatic intrusive activities in these areas in Hercynian period. Petrological and geochemical researches were conducted, and zircon SHRIMP U-Pb dating was performed for three granites, which yielded ages of (355±4) Ma, (359±4) Ma, (355±5) Ma respectively, suggesting that Dongqiyishan granitic batholith was formed in Late Devonian instead of in Middle Hercynian. It is thus thought that the collisional orogenesis in the Beishan Mountain during Early Late Paleozoic was accompanied by strong granitic magma activity, which played an important role in deepening the crustal evolution process of Palaeozoic in Beishan area. |
| YANG Yue-qing,LÜ Bo,MENG Gui-xiang,YAN Jia-yong,ZHAO Jin-hua,WANG Shou-guang,JIA Ling-long,HAN Jian-gang.2013.Geochemistry, SHRIMP Zircon U-Pb Dating and Formation Environment of Dongqiyishan Granite, Inner Mongolia[J].Acta Geoscientica Sinica,34(2):163-175. |
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