Forward geomechanical models over geological time scales require algorithms to simulate sedimentation and erosion. During sedimentation a new layer of sediment is added to the top surface of the model and the domain is remeshed. On the other hand erosion may be simulated by two approaches:

 

1.Deactivating the entire top stratigraphy formation and removing it from the model.

 

2.Calculating the intersections of the model geometry with an erosion datum and removing the sediment above the erosive surface.

 

Note that in both cases even though the eroded sediment is instantaneously removed from the domain its associated weight load is initially applied to the new top surface of the model and gradually ramped down over the erosion stage.

 

In these reference manual pages ParaGeo data structures and their corresponding keywords relevant to sedimentation and erosion are described. These include:

 

•Deactivation_data defining the removal of the entire top formation to simulate erosion.

•Sedimentation_data required to define that at the current simulation stage a sedimentation (and/or erosion) event is considered. All sedimentation relevant options are defined.

•Sedimentation_horizon defining the deposition surface (sedimentation datum).

•Sedimentation_parameters allows the definition of the default parameters for all sedimentation events in the simulation.

 

Note that sedimentation and erosion may also be modelled as a loading applied to the model by using the Stress_path_data data structure. Note however that in such case no sediment is added or removed from the domain and the top surface is always the same. Thus the change in flow pathways length due to sedimentation and burial for example is not taken into account.

 

 

 

Examples

 

Tutorial examples demonstrating sedimentation and erosion in ParaGeo are:

 

Mech_002: Uniaxial burial of 2000m of sediment

 

Mech_003: Rift Sandbox Simulation (Case2 and Case3)

 

Ex_005: Sedimentation and erosion operations