Eastward extension of the Solonker Suture beneath the central Songliao Basin, NE China: Evidence from a deep seismic reflection profile

Abstract

The Solonker Suture is one of the most important structures in central Asia and marks the location of closure of the Paleo-Asian Ocean and the assemblage of the North China and Siberia cratons during the Late Permian - Early Triassic. The suture is traceable for ∼ 700 km within the Central Asian Orogenic Belt, but its eastward extension beneath the Songliao Basin has not been defined. In this paper, we present a 127.3-km-long N–S deep seismic reflection profile across the central Songliao Basin. The data acquired from five large-size and four medium-size dynamite shots were used to generate a single-fold reflection profile imaging the Moho and the structures of the crust and upper mantle. The southern end of the profile reveals a northward-dipping reflector that extends 80 km into the mantle. This dipping reflector is interpreted as a fossil subduction zone. The new data from this study suggest that the Songliao Terrane may not be a single micro-continent block or orogenic belt but a composite terrane that comprises the North Accretionary Zone, South Accretionary Zone, and northern margin of the North China Craton from north to south. The fossil subduction zone is regarded as part of the NE-trending extension of the Solonker Suture beneath the central Songliao Basin.