A 3D two-way coupled DEM-FEM simulation framework for sediment faulting and salt deformation under ice loading

Glacial loading in salt-bearing sedimentary basins drives complex interactions between brittle sediment faulting and viscous salt flow, which standalone DEM or FEM models cannot fully capture due to extreme rheological contrasts. To bridge this gap, we developed a 3D two-way coupled DEM–FEM framework that integrates granular deformation in sediments and ice (Ansys Rocky) with visco-elasto-plastic salt flow (Ansys Mechanical) through Python-scripted bidirectional data exchange. We tested the framework on a 60 km basin subjected to differential ice loading (2–4 km thickness). The simulations show that salt mobility substantially amplifies and reorganizes deformation, increasing fault counts by 9.3% and average fault density by 20% compared to rigid-base models. Faulting increases non-linearly (≈16.5%) with ice thickness, while fault dips remain stable between 25.5° and 27.5°, indicating that orientation is governed by sediment friction rather than loading magnitude. These results demonstrate that salt flow exerts a first-order control on stress redistribution, focusing deformation near ice margins and within specific strata. The coupled workflow provides a reproducible tool for analyzing multiphysics feedbacks in rheologically layered glaciotectonic systems.