The growth and propagation of synsedimentary faults



Childs, C., Nicol, A.1, Walsh, J.J., Watterson, J.
Present Address:
1 - Institute of Geological and Nuclear Sciences Ltd, PO Box 30 368, Lower Hutt, New Zealand

Abstract - A growth fault offsets a sequence all or part of which was deposited while the fault was active. Where the sedimentation rate is equal to or exceeds the rate of throw, no persistent fault scarp is maintained. Offset of each syn-fault horizon therefore records the throw subsequent to its deposition, allowing successive growth stages of each fault to be determined. This technique has been applied to growth faults mapped on 3D seismic datasets to distinguish between faults which propagated laterally during their syn-sedimentary growth, faults which did not propagate laterally during this stage and faults in which the dimensions of the active surface decreased during syn-sedimentary growth. Static and retreating lateral tip-lines are associated with relatively high lateral throw gradients which, as on post-sedimentation faults, are associated with overlap of the fault strain field with that of a neighbouring fault most often with the formation of a fault relay zone. Stasis and retreat of fault tips is more prevalent in the later stages of fault system growth.


Journal of Structural Geology 25, 633-648, 2003.