Normal fault zone evolution and fault scarp degradation in the Aegean region

Abstract The initial stages of rift-basin evolution are periods of great landform change. Fault scarps are newly created axes of erosion which, along with footwall uplands, act as sediment sources for subsiding hanging wall basins. Scarps formed during neotectonic normal faulting of Mesozoic carbonates in mainland Greece and western Turkey display a varied pattern of degradation related to the history of fault development and variations in fault zone architecture. Alternating zone-parallel compact breccia sheets and incohesive breccia belts, of contrasting resistance to erosion, underlie scarps. Meso-scale slip-plane phenomena, such as corrugations, gutters, comb fractures, and pluck holes, together with geomorphological features, such as subsurface solution pipes, and vegetation result in initial variations in the denudability of erosionally resistant compact breccia sheets. Migration with time of slip-plane activity within a fault zone into its hanging wall (i.e. intrafault-zone hanging wall collapse) adds to the structural heterogeneity of fault scarp footwalls. Quaternary talus, whether offset across a fault, banked unconformably against a slip plane, or faulted against a reactivated slip plane, has a dampening effect on degradation. The complexities of fault zone architecture combined with a history of hanging wall collapse lead, in the Aegean region, to non-uniform degradation and scarps which are commonly stepped and occasionally cavitated.