LA-ICP-MS Zircon U-Pb Ages of Late Carboniferous Granites from Shangqi Area in Great Xing'an Range and its significance

The Shangqi area ofGreat Xing'an Range is tectonically located at the Xing'an Block in the eastern part of the Xingmeng oregenic belt. Large quantities of late Carboniferous granitic rocks are distributed in this area.Thesegranitic rocks are mainly composed of the quartz diorite and quartz monzodiorite. The LA-ICP-MS U-Pb zircon dating has yielded an age of (315.9±2.1)Ma, showing that the granite was mainly emplaced in late Carboniferousperiod. The petrogeochemical characteristics show that these granites are high-potassium, Si-saturated and quasi-aluminous rocks,belonging to calc-alkaline series.Discrimination diagrams show that the late Carboniferous granite belongs to I-type granite.These graniteswere formed in a post-orogenic or post-collisional tectonic setting, whichrepresents an extensional tectonic environment.The petrography,petrogeochemistry,chronology study and regional tectonic evolution reveal that these late Carboniferous intrusions from Shangqi area in Great Xing'an Range were formed under a tectonic setting from late-orogenic to post-orogenic extension during the collision between Xing'an and Songnen Massifs.