Magmatic sequence of Early Palaeozoic granitic intrusions and its tectonic implications in north Altay orogen, Xinjiang

作者：Dong LianHui^*; Qu Xun; Zhao TongYang; Xu ShiQi; Zhou RuHong; Wang KeZhuo; Zhu ZhiXin

来源：Acta Petrologica Sinica, 2012, 28(8): 2307-2316.

• Granite
• TTG combination
• Ridge subduction
• Early Paleozoic
• Altay
• Xinjiang

The Early Paleozoic intrusive rocks occupy 50% proportion of whole north Altay orogenic belt in Xinjiang. Based on a large number of high precision SHRIMP and LA-ICP-MS U-Pb zircon geochronology data in recent years, we have identified the Ordovician sequence before the collision and Silurian to Early Devonian sequence after collision in the orogenic belt. The former was composed of tonalite/oligoclase granite and granodiorite-monzonitic granite series, which belongs to the TTG combination, with isotopic age peak between 450Ma and 465Ma. The latter was composed of monzonitic granite-syenogranite and a small amount of alkali feldspar granite, belonging to the generalized GG combination, with isotopic age peak between 390Ma and 415 Ma. The former was mainly distributed in the south, the latter mainly distributed in the northern, showing that subduction zone was distributed in the south. According to the same isotopic ages, authors suggest that the both Armantai ophiolite belt on the south side and Altay magma belt on the north constitute ridge subduction system. The south Altay Late Paleozoic accretionary zones, the Erqisi deformation belt, north Junggar Late Paleozoic intra-oceanic arc belt are later on laminated products.

• 出版日期2012-8