Lithospheric electrical structural characteristics and implications for the Central–Northern part of the Songliao Basin and adjacent mountains

Abstract

Influenced by the superimposed transformation of the Palaeo-Asian Ocean tectonic domain, the Palaeo-Pacific Ocean tectonic domain and the Mongolia-Okhotsk Ocean tectonic domain, Northeast China experienced multiple periods of magmatic activity during the Meso-Cenozoic, forming a complex basin and ridge tectonic system and lithospheric structure; this area is important for geologists. In recent years, many studies have focused on the Cenozoic volcanic system, deep dynamic mechanism and deep structure, but the relationships of the contacts between the Songliao Basin and the mountains on both sides and the genesis of Songliao Basin dynamics are still controversial. A 3-D inversion of the 815-km magnetotelluric (MT) profile from Zhalantun, Inner Mongolia to Yanji, Jilin Province, reveals relatively low resistivities and vertical stratification of the central and northern Songliao Basin. The mountains on both sides exhibit high resistivities. The Harbin–Changchun and Nenjiang–Balihan fault zones are basin-controlling faults on the east and west sides of the Songliao Basin; they are both deep faults that cut the Moho. The Daqing and Harbin areas are considered potential areas for geothermal resource exploration and development, and the Jingpo Lake volcano is still at risk of volcanic activity. A deep dynamic genetic model of the study area is proposed based on the combined action of the subduction of the Palaeo-Pacific Plate and asthenospheric upwelling, which provides new geophysical constraints and a basis for studying the tectonic evolution and dynamic mechanism in Northeast China.