Late Paleozoic-Mesozoic tectonic evolution of the northeastern Asian continental margin revealed by sedimentary formations and fossil accretionary complexes

The Late Paleozoic-Mesozoic tectonic evolution in the northeastern (NE) Asian continental margin has been a controversial issue. Accretionary complexes (ACs) and sedimentary formations, as the direct material records of the reconstruction of plate subduction history and surface response, respectively, are the categorically ideal indicators to explore tectonic evolution of the NE Asian continental margin. This study reviews recent geological and geophysical advances about the crustal structures beneath the massifs and ACs such as the Yuejinshan and Raohe ACs and conducts a detailed dissection on lithology, degree of metamorphism and deformation, deep crustal structure, and formation time of these fossil ACs. These results, together with the coeval sedimentary formations and igneous rock associations, provide new insights for Late Paleozoic-Mesozoic tectonic evolution of NE Asian continental margin, i.e., the NE Asian continental margin experienced the evolution of two tectonic regimes during the Late Paleozoic-Mesozoic: 1) the stage of the Paleo-Asian Ocean tectonic regime, including a passive continental margin in the early stage of the Late Paleozoic, an active continental margin in the early Permian, and tectonic transition in the Triassic. A paleo-ocean occurred between the Jiamusi Massif and an unnamed massif during the Late Devonian-late Permian; and 2) the stage of the Paleo-Pacific tectonic regime, including the subduction onset of the Paleo-Pacific Plate beneath Eurasia in the Early Jurassic, the accretion and emplacement of the Jurassic ACs during the Late Jurassic-early Early Cretaceous, and the continuous westward subduction during the Late Mesozoic. The Yuejinshan AC was the product of the Paleo-Asian Ocean tectonic regime and formed during the Late Devonian-early Permian. Its final emplacement occurred in the late Permian. The Raohe AC was the product of the Paleo-Pacific tectonic regime and experienced the following stages: 1) the formation of seamounts and deposition of the terrigenous clastic sediments in the Middle-Late Jurassic; 2) the seamount-Eurasia collision in the Late Jurassic; 3) the northward migration of the embryo of the Raohe AC during the Late Jurassic-early Early Cretaceous (160-140 Ma); 4) the deposition of the early Early Cretaceous sediments; and 5) the final emplacement of the Raohe AC in the late Early Cretaceous (140-130 Ma).