Modelling interaction between salt and extensional tectonics by syntectonic sedimentation modelling by HCA numerical technique.

The forward modelling algorithm (Hybrid Cellular Automata, HCA) is a numerical, hybrid methodology between the cellular automata (CA) and the finite element method (FEM) philosophies. From the CA method it follows the principle of using large amount of cells to simplify links. On the other hand, each point is linked by physical and geometrical laws to the surrounding ones, thus following the FEM philosophy. Layered rock units are simulated by a mesh of a very large number of semi-independent cells. In the FORC2 2D application, this technique is used to simulate the behaviour of layered rocks undergoing deformation produced by salt doming and extensional faulting, and the influence of such tectonics on the deposition of syntectonic sediments.The synsedimentation was achieved by properly adding new cell strata on top of the structure with the proper link to the existing mesh. The careful simulation of the evolution of sedimentation through time allowed to recognise the individual contribution of salt doming and fault offsets in the present day distribution of the sediment thickness. Modelling of offshore sections in continental platform to slope transitional zones allowed to recognise that in areas where the cover of the salt units in not sufficient to induce diapirism, this is triggered in later time by the activity of listric faults that produce the necessary spatial variation in the overburden. The later activity of such domes should induce significant deformations also in the footwall region.