东昆仑祁漫塔格走廊域晚古生代—早中生代侵入岩岩石组合及时空格架

Petrotectonic assemblages and temporal-spatial framework of the Late Paleozoic-Early Mesozoic intrusions in the Qimantage Corridor of the East Kunlun belt

基于东昆仑造山带祁漫塔格构造走廊域晚古生代—早中生代侵入岩类的野外地质学、岩石学、时空分布和同位素定年资料,可以识别出5个构造岩浆阶段和5个构造岩浆带。研究区的岩浆活动主要集中于早中二叠世阶段、晚二叠世晚期—中三叠世早期、中三叠世、晚三叠世和晚三叠世—早侏罗世。早中二叠世阶段的岩浆活动产物为花岗闪长岩+(斑状)二长花岗组合、石英闪长岩+斑状石英闪长岩组合及闪长岩+石英闪长岩组合,晚二叠世晚期—中三叠世早期(254.1～240.6Ma)为(斑状)二长花岗岩+正长花岗岩组合;中三叠世(安尼期晚期—拉丁初期)为闪长岩+石英闪长岩+花岗闪长岩+英云闪长岩组合;晚三叠世(212～225Ma)为石英二长闪长岩+花岗闪长岩+(斑状)二长花岗岩+正长花岗岩组合;晚三叠世—早侏罗世(瑞替—郝塘期)代表性的岩石组合为石英二长岩+(斑状)正长花岗岩+碱长花岗岩。这些火成岩组合有规律地分布在构造走廊域内,是揭示东昆仑造山带构造演化的关键所在。

Based on field geology, petrographic characteristics, spatial and temporal distribution and isotopic dating of the Late Paleozoic-Early Mesozoic intrusions in the Qimantage Corridor of the East Kuniun orogenic bek, the authors have recognized five tectono-magmatic stages and five intrusive beks. Magmatism in this area can be divided into the Early-Middle Permian, Late Permian-Middle Triassic, Middle Triassic, Late Triassic and Late Triassic-Early Jurassic stages. In the Early-Middle Permian stage, such assemblages as granodiorite ＋ monzogranine ＋ porphyroid monzogranite, quartz-diorite ＋ porphyroid quartz-diorite and diorite ＋ quartz- diorite were produced. The monzogranite ＋ porphyroid monzogranite ＋ syenogranite assemblage was formed in the Late Permian-Mmiddle Triassic period, the diorite ＋ quartz-diorite ＋ tonalite ＋ granodiorite assemblage was emplaced in the Middle Triassic period, and the Late Triassic intrusions were composed of the quartz- monzodiorite ＋ granodiorite ＋ porphyroid monzogranite ＋ syenogranite assemblage. The representative intrusion assemblage produced in the Late Triassic- Early Jurassic period is the quartz-monzonite ＋ porphyroid syenogranite ＋ alkali feldspar granite. These igneous assemblages are regularly distributed in the corridor and seem to be the key to revealing the tectonic evolution of the East Kuniun orogenic belt.