This example shows how to model deposition with erosion in a fold. The erosion model used in this case uses a sedimentation horizon to perform erosion and sedimentation. Using this model during a sedimentation event, the sediment which lies above the sedimentation horizon is eroded whereas any accommodation space existing between the sedimentation horizon and the current top surface is filled with new sediment. For the eroded sediment the way this algorithm works is:

 

1.At the start of a sedimentation stage intersections of the sedimentation horizon with the current geometry are calculated.

2.The stresses and pore pressure state at the intersections is stored.

3.The sediment above the sedimentation horizon is removed and the space between the current top surface and the sedimentation horizon is filled with new sediment.

4.The stress and pore pressure corresponding to the eroded sediment is applied as a load and is ramped down during the sedimentation/erosion stage (following the assigned time curve for gravity initialisation for the new deposited sediment).

 

In this case the starting 3D geometry considers a fold with 13 formations with a marked relief at the top surface. A sedimentation horizon intersecting the fold crest is considered. The simulation will consider a gravity initialisation stage and a deposition/erosion stage. For simplicity the model considers elastic material and solution of the mechanical field only (drained analysis assuming hydrostatic state).

 

Initial geometry

 

The data file Ex_005_Case3b.dat for the example is found in: ParaGeo Examples\General Examples\Ex_005\Data