Seismological Constraint of the Fossil Suture Zone: A Case Study in the Eastern Central Asian Orogenic Belt

Abstract The tectonic attributes of the fossil suture zone are crucial for reconstructing tectonic evolution, but they remain contentious due to inadequate crustal constraints. This study introduces a high‐resolution crustal structure derived from a cost‐effective short‐period dense seismic array across fossil suture zones between the Xing'an and the Songnen‐Xilinhot blocks in the eastern Central Asian Orogenic Belt. Our imaging reveals clear southward and northward subduction remnants of the fossil subducted slabs in the Solonker suture, along with weak subduction signatures in the Heihe‐Hegenshan suture. Combined with geological evidence, these findings indicate that the bi‐directional subduction remnants were related to the closure of the Paleo‐Asian Ocean in the Solonker suture from the Ordovician to the Early Triassic. Therefore, the identification of the fossil suture zones underscores the utility of dense short‐period seismic arrays in providing cost‐effective constrains on “frozen‐in” crustal information pertinent to tectonic evolution.