KineDyn: Thermomechanical forward method for validation of seismic interpretations and investigation of dynamics of rifts and rifted margins

Abstract

Physical processes interact during rifting to produce a range of crustal and sedimentary architectures and subsidence histories. Methodologies to analyze these processes combine techniques such as cross-section restoration, backstripping and numerical simulations. Despite the valuable outcomes of each method, intrinsic limitations related to particular interactions between kinematics and thermo-mechanics leave open questions on how seismic interpretation is consistent in terms of thermomechanical aspects of lithospheric extension. In this work, we present a new modelling technique, KineDyn, to simulate basement architecture, heat-flow, subsidence and sedimentation patterns along a given basin-scale seismic reflection profile in 2D. KineDyn is the fusion of dynamic thermomechanical approach and kinematic forward modelling of faulting and excludes drawbacks of conventional methods while preserving their valuable outcomes. In our approach, faults are initially controlled by prescribed initial locations, slips and timings, while the rest of the model is resolved in a fully dynamic mode, with non-linear visco-elasto-plastic rheology. KineDyn allows dynamic simulation of the response of the lower crust and mantle to different patterns of faulting in time and space and direct comparison to seismic observations. Thus, it gives, in effect, the same results as existing section restoration techniques (i.e. the potential history of faulting) and forward modelling techniques (i.e. the likely history of sedimentation, thinning, heat flow and subsidence), while simultaneously taking into account non-linear interactions between processes occurring during rifting. In addition, comparison of the model outcomes to lithospheric-scale seismic observations gives insight into the relationship between shallow crustal structures and deeper geodynamic processes in the lithosphere-asthenosphere system, which shape rifts.