Geodynamic Model Reveals Erosion Process of North China Craton

Researchers from the China University of Geosciences in Beijing, led by Professor Shaofeng Liu, have shed light on the mysterious transformation of the North China Craton (NCC). This research, published in Nature Geoscience, presents a groundbreaking model that explains the processes behind the gradual erosion of the craton, which began in the Mesozoic. Using detailed mantle flow models, Liu’s team has traced how tectonic forces deep within the Earth have destabilized this ancient part of the continental crust, challenging long-held assumptions about craton stability.

Reconstruction of ancient tectonic forces

In a recent study published in Natural Geosciences, the model suggests that it is beneath the Eurasian plate where the NCC is located. Unlike typical subduction, this plate did not immediately sink into the mantle. Instead, it slid horizontally beneath the NCC’s crust, weakening its foundation in a process known as flat-slab subduction. Using seismic and stratigraphic data, the team reconstructed this tectonic behavior and revealed how the unusual movement triggered chemical reactions that steadily eroded the NCC’s once stable base.

Three stages of deformation

The research identifies three key phases in the deformation of the NCC. First, as the Izanagi plate began to sink, it exerted a horizontal pressure that changed the composition of the NCC’s foundation. In the second phase, the plate eventually rolled back, causing it to sink deeper and causing a thinning effect on the lithosphere. This rollback phase also caused upward movement of the surface and the formation of rift basins. In the final phase, a ‘mantle wedge’ – a zone of partially molten material – formed between the subducting plate and the craton, further eroding the base and promoting volcanic activity.

Implications for geological understanding

This study provides a more nuanced view of how tectonic and mantle forces interact to erode stable crustal structures over time. Liu’s model provides insight into the transformation of the NCC and advances our understanding of craton stability, with practical implications for exploring mineral deposits essential to the technology. The research paves the way for future research into the complex life cycles of the Earth’s crustal plates and provides insight into ancient geological processes that shape the modern landscape.