Flexural strike-slip basins

Derek Neuharth,Chris K Morley,Jean Braun,Sascha Brune,Anne Glerum,Xiaoping Yuan

doi:10.1130/g49351.1

Abstract

Abstract Strike-slip faults are classically associated with pull-apart basins where continental crust is thinned between two laterally offset fault segments. We propose a subsidence mechanism to explain the formation of a new type of basin where no substantial segment offset or syn-strike-slip thinning is observed. Such “flexural strike-slip basins” form due to a sediment load creating accommodation space by bending the lithosphere. We use a two-way coupling between the geodynamic code ASPECT and surface-processes code FastScape to show that flexural strike-slip basins emerge if sediment is deposited on thin lithosphere close to a strike-slip fault. These conditions were met at the Andaman Basin Central fault (Andaman Sea, Indian Ocean), where seismic reflection data provide evidence of a laterally extensive flexural basin with a depocenter located parallel to the strike-slip fault trace.

Highlights

Text S1: ASPECT Methods 1.1 Governing equations We perform numerical simulations of a 3D strike-slip system using the open source finite-element code ASPECT (Advanced Solver for Problems in Earth’s ConvecTion, version 2.3.0-pre, commit 886749d; Heister et al, 2017; Kronbichler et al, 2012; Rose et al, 2017; Bangerth et al, 2019)
The plugin has three main components: 1) Copy the surface height and velocity values from ASPECT. 2) Initialize and run FastScape at a resolution equivalent to or greater than the one used at the surface of ASPECT. If it is the first timestep of the tectonic model run, FastScape is initialized using height and velocity values from ASPECT
The FastScape mesh includes an additional element-size layer of ghost nodes compared to the ASPECT surface mesh

Summary

Introduction

Text S1: ASPECT Methods 1.1 Governing equations We perform numerical simulations of a 3D strike-slip system using the open source finite-element code ASPECT (Advanced Solver for Problems in Earth’s ConvecTion, version 2.3.0-pre, commit 886749d; Heister et al, 2017; Kronbichler et al, 2012; Rose et al, 2017; Bangerth et al, 2019). 2) Initialize and run FastScape at a resolution equivalent to or greater than the one used at the surface of ASPECT.

Results

Conclusion