Abstract - Serial cross-sections of faults within soft sediments of Miocene age, on the East coast of Denmark, were collated to provide 3D datasets with which to study the geometry of minor faults (displacements < 10cm). From the wide variety of geometrical complexities displayed by these faults, many due to mutually cross-cutting relationships between opposed dipping faults, we present relatively simple structures considered to demonstrate stages in the evolution of relays zones between pairs of fault segments within a fault array. Some of the fault surface geometries described have been previously speculated upon but not observed. The structures described are 1) initial embayments in fault tip-lines 2) established relay zones displaying transfer of displacement between overlapping fault segments 3) breached relay zones and 4) fault bounded lenses. An individual relay zone may display more than one of these structures along it’s length and relay zones which are breached on one cross-section may be inact along strike in one, or occasionally both directions. Examples of relay zones which give way along strike to a continuous straight fault in both directions are also observed. Relay zone breaching occurs by propagation of the initial parent fault through the relay zone rather than by the formation of a new breaching fault.
Journal of Structural Geology 30, 257-272.