We propose the assembly fabric of the Songnen and Xing’an blocks is “crocodile”.
We verified the GXAR experienced the delamination and the underplating, which is very common in the eastern part of the CAOB.
We propose the building of the GXAR could divide into two phases: a) the early crustal shortening and overlapping in later Paleozoic; b) the later vertical accreation in Mesozoic–Cenozoic subsequently.