ABSTRACT

This paper concentrates on some aspects of thrust faulting in a layered sequence. First, the fact that thrust faulting, as the name implies, constitutes duplication of the sequence is considered. The effects of loading due to an advancing thrust sheet are studied. In particular, the effect of the load on the fluid pressure in the underlying beds is reviewed. Second, the peculiar geometric attitude of thrust faults in layered sequence; i.e., the stepping, is discussed. Further, the apparent ease with which movement takes place along faults of this type is investigated, and previously advanced theories are supplemented. Such factors as the pore pressure, the existence of bedding planes (planes of weakness) and the unequal distribution of the stresses in a layered sequence under horizontal compression are all considered important when trying to understand the mechanics of overthrust faulting.