Was there an active continental margin arc along the western margin of Zhangguangcailing Terrane in the eastern Central Asian Orogenic Belt?

The Central Asian Orogenic Belt (CAOB) is one of the huge accretionary orogenic belts on the earth. NE China in the eastern segment of CAOB consists of several blocks connected by the accretionary belts and suture zones. The subduction and accretion of the Paleo-Asian Ocean (PAO) during the late Paleozoic around the Jiamusi Block and Zhangguangcailing Terrane (ZGCT) has been a subject of debate in terms of location, polarity, and timing. Our study found that the western margin of the ZGCT developed Early Carboniferous felsic magmatism with ages of 356–334 Ma newly obtained by LA–ICP–MS zircon UPb dating. These igneous rocks, including strongly peraluminous rhyolites and I-type granites and rhyolites, display geochemical characteristics of medium- to high-K calc-alkaline series, and most of them have positive εHf(t) values, indicating an active continental margin setting. On the other hand, the Early Carboniferous magmatism was absent in the Jiamusi Block. Therefore, we suggest there existed a branch of the PAO that extended north-south along the western margin of the ZGCT. The magmatism in the western margin of the ZGCT migrated eastward to the western Jiamusi Block during the Carboniferous, accompanied by an increase in the depth of magma source, indicating an eastward advancing subduction of the PAO. The latest Carboniferous–earliest Permian marked a period of tectonic regime transition, during which the eastward-subducting plate along the western margin of the ZGCT began to roll back, resulting in the formation of bimodal volcanic rocks and A-type rhyolites across the ZGCT with a slight westward younging trend. Simultaneously, the eastern margin of the Jiamusi Block started to be controlled by the westward advancing subduction of the Panthalassa plate. •A newly found Early Carboniferous magmatic arc in western Zhangguangcailing Terrane.•There developed an eastward subduction along the western Zhangguangcailing•Terrane.•Zhangguangcailing Terrane was the western margin of Jiamusi Block in late Paleozoic.