How to Model Coupled Fault Growth and Associated Sedimentation

Rudkiewicz, Jean-Luc¹, Didier Granjeon¹, Marie-Christine Cacas², Emily Albouy³ (1) IFP, 92852 Rueil Malmaison Cedex, France (2) IFP, Rueil Malmaison, France (3) N/A,

Numerous techniques exist to describe the kinematic of fault growth, when large scale horizontal deformation occurs. Fault bent fold or flexural slip are some of the most commons. Stratigraphic modelling, aimed at represent the sediment transport, is generally based upon the transport of sediments into an available accomodation space, as reconstructed with vertical backstripping.

This paper presents a method to link both fault growth with large offset and syntectonic sedimentation, combining the advantages of two methods. The method is based on the successive modelling of deformation and sedimentation. The basic idea is to couple sedimentation and deformation only at specific steps in the basin history. Therefore, the basin is described by a set of forward structural modelling snap shots, creating topographic surfaces that are not at depositional equilibrium. Subsequent sediment erosion and deposition will bring back the basin to equilibrium if no further horizontal deformation occurs, or will generate sedimentary wedges that might be involved in further deformation. Hence the interplay between rate of sediment transport and rate of deformation can be investigated.

The coupling between deformation and sedimentation is based upon a down-scaling, upscaling approach that will be illustrated with simple geologic configurations. This coupled modelling can be used for example to predict the occurrence of clastic erosional facies in a thrustbelt, resulting from a given history of deformation. Inversely, it can also help to describe the kinematic of fault movement, as recorded in the syntectonic sequence.