Faults displacing inclined beds
These four models deal with the geometrical consequences of a fault displacing inclined beds: in all cases bed dips and related folding pre-date faulting. The models, and associated exercises, are intended to be performed in sequence. You should start with Part I, the other three parts give you the additional information you need in order to answer the question: "What is the sense of movement along the fault in model Part I?"
Inclined beds Part I
Start the exercise with this model. Try to determine the sense of slip along the fault. Though there is no unique solution to this geometric configuration, the fault cannot be reverse.
Inclined beds Part II
Combine Part II with Part I. Again there is no unique solution to this geometric configuration. However, if the top surface of the hangingwall and footwall is a pre-faulting erosional surface, then the fault must be a pure dip-slip normal fault.
Inclined beds Part III
Combine Part I and III so that the hangingwall and footwall beds are folded (providing a chevron fold, with either a synformal or antiformal geometry). The slip direction of this fault can be resolved because the bedding, the fold axial plane and, most important, the fold axes are useful markers for estimating movement. The model illustrates the apparent, but opposing, map-view strike-slip offsets of beds on either limb of a fold cross-cut by a normal fault.
Inclined beds Part VI
Combine Part I and IV to provide a synform in both the hangingwall and footwall of the fault. This model shows how fold axes can be used to estimate the amount and direction of slip across a fault. In this case the fault is an oblique-slip fault, with a larger component of sinistral strike-slip than normal dip-slip: the apparent map-view offsets of beds on both limbs are now sinistral.