Role of the sediment routing system in basin analysis

Category Sedimentology
Group GSI.IR
Location International Geological Congress,oslo 2008
Author ALLEN, PHILIP A.۱; Whittaker, Alexander۱; Whitchurch, Amy۱; Fedele, Juan Jose۲; Paola, Chris۳
Holding Date 11 October 2008

Basin models conventionally involve the deformation of the lithosphere when stretched or flexed, but the modelling of the filling of sedimentary basins is dependent on incorporating surface processes of weathering, sediment release and dispersal, and long-term burial in the basin. This integrated process system from source to sink is the sediment routing system. Tectonics and sediment routing systems are closely coupled.
The simplest coupling is shown by the role of tectonics in generating upland topography that serves as the erosional engine of the sediment routing system, and the accommodation that is fully or partially filled with stratigraphy. When perturbed by changes in tectonic boundary conditions, such as a change in the slip-rate of a border fault, or the change in the plate slip vector in a convergent mountain belt, these systems respond transiently with predictable ’relaxation’ times. At a more sophisticated level, the vigour of surface processes in relation to tectonic fluxes is a first-order control on structural styles, frontal propagation of deformation and local amplification of deformation in fold-thrust wedges and arrays of extensional faults. Burial of mountain fronts in a thick sediment blanket may indeed be responsible for a cessation of frontal growth. Dispersal of a mixed sediment supply into a basin with a certain spatial pattern of tectonic subsidence also controls the regional slope and downstream granulometric fining of the depositional system, the positioning of discontinuities such as the gravel front, and gross depositional facies. This offers the possibility that certain basin types may be occupied by particular styles of sediment routing system.
Model results and case studies will be presented that illustrate the range of linkages between basin mechanics, sediment routing systems and stratigraphic products.