Abstract:

The growth thrust fault belts discussed in this paper are referred to as the thrust belts that are situated between the fold mountains around the compressive basins and marginal depressions of inland basins and regional thrust belts within the basins as boundary of the secondary structural units in West China. The evolution of this kind of thrust faults may be divided into 3 stages: 1. Early upthrusting stage with the upper wall as the active one; 2. Con-temporanous sliding stage with the bottom wall as the active one; 3. Upwardsgrowing stage dominated by diffefential sedimentation. These stages can be taken as a complete evolution cycle of the faults, and complicated thrust belts may be resulted from multicycles. Oil and gas exploration in the thrust belts needs a lot of money, and is fullof risks. Only subterranean thrust belts which are associated with oil-generation depression or which intensely thrusted at the early stage but weakened down at the late stage can be taken as exploration target.