Continental Margin Process Analysis, Structures & Stratigraphy
Interaction of lithospheric deformation processes, regional tectonic faulting and synkinematic sedimentation in segmented rift basins.
Supervisors: Dr Jürgen Adam Dr Marta Perez, Prof J.Phipps Morgan
The The regional variation in crustal architecture and tectono-stratigraphic evolution of segmented rift basins is governed by their previous crustal deformation history, the interplay with margin-scale lithospheric ductile deformation, the pattern of basin-scale fault localization & evolution, and the pattern of synrift sediment flux. Regional evolution of the rift architecture and underlying mantle structures form the foundation of the future rifted conjugate continental margins, associated sedimentary basins and petroleum systems.
Scaled analogue experiments are able to simulate 3D brittle faulting and synkinematic sedimentation at high spatial resolution. Numerical models, on the other hand, are capable of simulating the thermo-mechanical evolution that ensues from extension of the lithosphere and thus can quantify the thermal subsidence, lower crustal flow and mantle flow that occur beneath upper crustal basins. The two techniques are thus highly complementary. In this project, we plan to integrate 2D numerical geodynamic models and 3D scaled analogue experiments to couple dynamic simulation of lithospheric, tectonic and depositional processes during continental rifting. This will enable a systematic analysis of key processes and control factors on margin formation and how these processes influence stratal architectures and petroleum system evolution in syn-rift and post-rift sedimentary basins.
3D fault pattern and synkinematic sediment pattern in the segmented Assal rift basin, Djibouti, Afar Triangle (oblique view, Google Earth version 18.104.22.16801, access date: 27 March 2012).
Numerical and analog methods will be combined to design a nested experiment with mutually constrained boundary conditions. Finite-Element 2D margin-scale dynamic models will simulate the deformation of the lower crust and mantle in a series of continental margin transects. These coupled thermo-mechanical numerical simulations will provide boundary conditions for scaled 3D analogue experiments (e.g. extension rates of rift shoulders, uplift/subsidence rates and stretching rates along the base of upper crust). In turn, analogue experiments results, which constrain the evolution of the crustal rift structures and rift basin architecture, will feed back the loading effects of fault kinematics, sedimentation, and erosion as boundary conditions at the base of the upper crust in ongoing iterations of the scaled 3D analog experiments. Various sediment transport and depositional scenarios will be implemented to investigate the effects of regional climate on margin formation (see also PhD project 4).
A major aim of the project will be to refine and extend techniques and workflows like the one described above in order to integrate computational geodynamic modelling techniques with basin-scale analogue experiments for the realistic simulation of rifting processes and basin evolution of segmented and linked rift basins for margin segments and conjugate margins.
Specific deliverables of PhD project 3 are:
- Methods, equipment and experiment workflows for coupling of analogue experiments and numerical stratigraphic models to simulate dynamic tectonic-depositional systems from basin to reservoir scale
- Tectono-stratigraphic analysis, simulation and reconstruction of structural and stratal architectures during the syn-rift and post-rift evolution of selected salt basins on South Atlantic conjugate margins
- Sensitivity Analyses of the influence of key depositional variables (sediment input, sediment transport and depositional environment) on salt basin evolution and their variability along-strike of South Atlantic margin segments