Abstract - The interpretation of fault kinematics from geometric data is an essential step in developing an understanding of the growth of fault systems. Constraints on fault geometry are, however, often restricted to 2-D maps or cross-sections. Analysis of well constrained 3-D fault geometries from outcrop, mine and 3-D seismic datasets provides a means of assessing the extent to which kinematic interpretations of faulting benefit from a 3-D geometrical perspective. Concentrating on relay zones and segmented normal fault arrays, we suggest that very different interpretations of their evolution arise from the recognition that rarely will the propagation directions of faults, and fault segments, be contained within the inspection plane of 2-D, map or cross-sectional, data. A 3-D perspective favours the initiation and 3-D propagation of many such arrays as kinematically coherent systems in which individual segments may even link into a single fault surface out of the plane of inspection. We argue that this model, which conflicts with the often suggested model of incidental overlap of originally isolated faults, should be the preferred model for the generation and growth of segmented normal fault arrays.
Abstract of talk given to:
Irish Geological Research Meeting, Dublin, February 2002