Tectonic evolution of the eastern Central Asian Orogenic Belt during the Carboniferous–Permian

Abstract

The eastern Central Asian Orogenic Belt (CAOB) is an interactive area of multiple tectonic regimes. In the past decades, researchers have conducted extensive studies in the eastern CAOB over the past decades and reported plenty of new data. However, there are still many open questions and arguments dealing with the correlation and tectonic affinity of different blocks with Precambrian crystalline basements, the subduction tectonic processes, and the initiation time of the oceans surrounding the blocks at the eastern CAOB. In this study, we provide a detailed review of the tectonic evolution of the Precambrian blocks in the Eastern Mongolia, NE China, and Far East Russia and provide a regional comparison and correlation of the different tectonic units in the region, initial subduction of Mongolia–Okhotsk Ocean and Pathalassa Ocean, and set up a tectonic evolution model from Carboniferous to Permian. In the late Early Paleozoic, the Ereendavaa Block in Eastern Mongolia and the Erguna and Jiamusi Blocks in NE China, as well as the Mamyn and Bureya Blocks in the Far East Russia, respectively formed the Ereendavaa–Erguna–Mamyn Block chain (EEMB) and Bureya–Jiamusi–Khanka Block chain (BJKB) were formed and probably connected and constructed a long united block chain. Combined with the geochronological and geochemical data of the late Paleozoic magmatic rocks from these tectonic units, we suggest that the southeastward subduction of the Mongolia–Okhotsk Ocean along the northwestern margin of the EEMB was initiated in the Late Carboniferous, then the westward subduction of the Panthalassa Ocean along the eastern margin of the BJKB was subsequently initiated in the Late Carboniferous, indicating that the initial subduction around outside of which migrated from west to east. With the continuous subduction of the Mongolia–Okhotsk Ocean and Panthalassa Ocean, the EEMB–BJKB block chain underwent further bending, forming a southward–opened curve and constituted the NE China Orocline.