Dynamical significance of the Tanlu Fault Zone in the destruction of the North China Craton: The evidence provided by the three-dimensional Magnetotelluric array study

Due to the subduction of the Paleo-Pacific Plate below the East Asian continent, the North China Craton (NCC) is considered to have been thinned in the Mesozoic, with the lithosphere of its east portion significantly thinned. As the eastern boundary of the NCC, The Tanlu Fault Zone (TLFZ) is one of the largest strike-slip fault systems in eastern Asia. Tanlu is believed to have recorded the destabilization of the NCC. Magnetotelluric array data collected in the TLFZ and adjacent areas are obtained to image the lithospheric three-dimensional resistivity structure and to discuss the structural constraints on this event. According to the resistivity model from the three-dimensional inversion, the crust of the Luxi Uplift (LXU) to the west of the TLFZ and the crust of the Sulu Orogenic Belt (SOB) to the east of the TLFZ exhibits high resistivity (>300 Omega m). Lithospheric mantle of the SOB also exhibits highly resistive characteristics. Conversely, the LXU mantle showed distinct low-resistivity characteristics (C3). Low-resistivity anomalies were found corresponding to both branches of the TLFZ. The eastern branch is a lithospheric low-resistivity belt, while the western branch formed a significant mantle resistivity boundary between the low-resistivity LXU and the high-resistivity SOB. Thus, we considered that molten materials may have upwelled along the weak area of the western branch, inducing a significant lithospheric thinning beneath the LXU. On the other hand, the lithosphere of the SOB has not been significantly thinned according to its high resistivity. The significant contrast of the resistivity may indicate that the western branch of the TLFZ is the boundary between the NCC and the SOB, with the sinistral strike-slip occurring along it.

Automated summary

Based on magnetotelluric array data collected in the Tanlu Fault Zone (TLFZ) and adjacent areas, it was found that the crust of the Luxi Uplift (LXU) to the west and the Sulu Orogenic Belt (SOB) to the east of the TLFZ exhibit high resistivity characteristics, while the mantle of the LXU shows low-resistivity characteristics. Low-resistivity anomalies were found corresponding to both branches of the TLFZ.