ZIRCON U-PB AGE AND TECTONIC SETTING OF THE MIDDLE ORDOVICIAN INTRUSIVE ROCKS IN DUOBAOSHAN AREA, HEILONGJIANG PROVINCE

The Duobaoshan area is located in Zhalantun-Duobaoshan island arc tectonic belt in the eastern section of Xing'an-Mongolian orogenic belt, with the Early Paleozoic geological bodies developed and closely related to regional mineralization. The formation age, tectonic setting and mineralization are discussed based on the study of petrography, lithogeochemistry and isotopic chronology of the Middle Ordovician intrusive rocks in Duobaoshan area. The LA-MC-ICP-MS zircon U-Pb age of granodiorites is 488±3 Ma, indicating that the granodiorites were formed in the Middle Ordovician. The magma source is mainly mantle origin with some crust-derived materials. With intensive tectonic thermal events and magmatic intrusion-eruption activities, a large number of deep fluids bring metallogenic elements such as Au and Cu to form Duobaoshan Cu-Mo deposit under favorable minerogenetic conditions and expanded space.