Destruction of the North China Craton: Evidence from the electrical structure and fluid content

Abstract

The three-dimensional resistivity model of the lithosphere and fluid content plays a significant role in analyzing the spatiotemporal distribution and dynamic reasons for the North China Craton (NCC) destruction. The conductivity is related to temperature and melt fraction using laboratory experiments. The Hashin-Shtrikman (HS) bounds are used to constrain the conductivity range of rocks in the solid and solid-melt systems. The authors established the lithospheric conductivity-temperature relationship by combining the mineral composition obtained from the analysis of xenoliths, the steady-state heat conduction equation, water, and carbon dioxide. To discuss the destruction of the NCC, the three-dimensional resistivity structure model obtained from the magnetotelluric sounding (MT) array inversion of the NCC is compared with the model calculated using the HS bounds. The research results show that the higher the volatile water and carbon dioxide content in the fluid, the lower the mantle solidus. Based on the melt fractions of the Ordos Block, Trans-North China Orogen, and Bohai Bay Basin, the speculated lithosphere-asthenosphere boundary (LAB) exhibits the characteristics of deep in the west and shallow in the east. The partial melting of the Bohai Bay Basin began at a shallower depth than other places, with a more significant difference in fluid content in the depth.