LINKAGES BETWEEN PATTERNS OF FORELAND BASIN SEDIMENTATION AND THRUST BELT EVOLUTION

The linkage from orogenic activity to foreland basin sedimentation is well established, however, potential feedback processes operating in the opposite direction have not been fully evaluated. We suggest that the properties of a characteristic foreland basin stratigraphic succession influences the structural development and growth of foreland fold and thrust belts in predictable ways and that this relationship may be a common feature in the evolution of convergent orogenic systems. A fundamental feature of foreland basins is the onset of rapid subsidence and deposition of a coarsening-upward sedimentary succession. At the base of this succession are fine-grained depositional units related to back-bulge and distal foredeep sedimentation. As the orogenic wedge enlarges through frontal accretion, the foreland is incorporated into the thrust belt and the early foreland depositional units are systemically exploited as a décollement or detachment zone, often culminating in multiple decollement levels. The presence of multiple décollements within a fold and thrust belt affects the structural evolution of an orogen and has implications for wedge dynamics, patterns of exhumation, and tectonic processes.