Incorporating High-Fidelity Surface Processes Into Large-Scale Tectonic Models of Passive Margin Formation

Abstract

The evolution of sedimentary systems within rift basins is primarily controlled by the feedback interaction of surface processes and tectonics. Deformation along a margin provides material for erosion/transport and accommodation space for deposition; while changes in climate influence the supply and transport of source materials, and subsequently the total isostatic and thermal impact of sediment from source to sink. Despite the recognition of this link, decoding the sedimentary signals recorded in basins of the relative impact of surface vs. tectonic forcing remains a significant challenge. This problem is due, in part, because analogue and 2D numerical models are unable to simulate the non-linear thermo-mechanical feedback loops between high-detail surface processes (sediment yield, dispersion, stratigraphy) and the large-scale (spatially and temporally) tectonics of continental rifting. To overcome this limitation, we have coupled a set of self-consistent numerical frameworks capable of simulating the landscape evolution on a thermally and mechanically realistic lithosphere under tectonic forcing. With this coupled framework, we can investigate the evolution of basins down to the grain-scale, while incorporating the influences of isostatic, tectonic, and deep Earth forces. To demonstrate this new toolkit, we have run a number of experiments on rifting continental lithosphere under different climatic forcing. By varying the mode of surface processes (none, elevation thresholds, self-consistent coupling), we find that only the coupled model is able to produce the range of natural complexities seen in nature, including migration of depocentres, transition of sinks to sources, thermal blanketing, and dynamic links between surface loading/unloading and faulting. This work is part of the Basin GENESIS Hub, a new 5-year project based on a consortium of Australian Universities and industry partners. By combining existing and new workflows for climate, stratigraphic, tectonic, and mantle convection modelling into a cohesive workbench, we hope to develop new knowledge incorporating deep to surface processes involved in the formation and evolution of basins. This also opens opportunities for data assimilation methods and uncertainty quantification, leading to a new generation of 5D basin models (space, time, uncertainty).

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015