Rheological Controls on Intracratonic Rifting: Insights from Stratigraphic Reconstruction and Geodynamic Modeling of the Mesoproterozoic Yanliao Aulacogen

The Meso-Neoproterozoic Yanliao Aulacogen in the northern North China Craton (NCC) preserves a critical sedimentary record of the Columbia supercontinent breakup. However, the geodynamic mechanism driving its episodic subsidence and distinct asymmetric architecture (e.g., the "north-faulted, south-overlapping" geometry) remains debated. Specifically, how the rigid cratonic lithosphere accommodated significant extension under the hotter thermal conditions of the Mesoproterozoic represents a geodynamic paradox. To address this, we integrate geological prototype basin reconstruction with 2D thermo-mechanical modeling (ASPECT).

Constrained by stratigraphic correlations and detrital zircon provenance data from the Yanliao and Liaodong areas, we performed a systematic parametric study to test the sensitivity of rift evolution to mantle potential temperature (T_p) and lithospheric rheology. Our reconstruction reveals a rapid subsidence phase coincident with regional magmatism (~1.38 Ga). Correspondingly, numerical results indicate that simple mechanical stretching is insufficient to localize strain within the thick cratonic keel. Instead, a melt- or fluid-induced rheological weakening mechanism is required to reproduce the observed lithospheric thinning and basin depth. We propose that the Yanliao Aulacogen marks a transition in tectonic style, where the interplay between a hot, weak lower crust and magmatic pulses controlled basin evolution. This study provides new quantitative constraints on the geodynamic regime of NCC and highlights the necessity of incorporating Precambrian-specific rheological laws in ancient basin analysis. It not only reconstructs the paleogeography of the Yanliao Aulacogen but also provides quantitative constraints on the geodynamic regime of the NCC during the supercontinent cycle.