Normal faults occur in a variety of geodynamic environments, both in subsiding and uplifting areas. Normal faults may have slip rates faster or slower than regional subsidence or uplift rates. The total subsidence may be defined as the sum of the hangingwall subsidence generated by the normal fault and the regional subsidence or uplift rate. Positive total subsidence obviously increases the accommodation space (e.g. passive margins and back-arc basins), in contrast with negative total subsidence (e.g. orogens). Where the hangingwall subsidence rate is faster than the sedimentation rate in case of both positive and negative total subsidence, the facies and thickness of the syntectonic stratigraphic package may vary from the hangingwall to the footwall. A hangingwall subsidence rate slower than sedimentation rate only results in a larger thickness of the strata growing in the hangingwall, with no facies changes and no morphological step at the surface. The isostatic footwall uplift is also proportional to the amount and density of the sediments filling the half-graben and therefore it should be more significant when the hangingwall subsidence rate is higher than sedimentation rate.
Normal faulting vs regional subsidence and sedimentation rate / Doglioni, C; D'Agostino, N; Mariotti, G. - In: MARINE AND PETROLEUM GEOLOGY. - ISSN 0264-8172. - 15:8(1998), pp. 737-750.
Normal faulting vs regional subsidence and sedimentation rate
DOGLIONI, C
;MARIOTTI, G
1998
Abstract
Normal faults occur in a variety of geodynamic environments, both in subsiding and uplifting areas. Normal faults may have slip rates faster or slower than regional subsidence or uplift rates. The total subsidence may be defined as the sum of the hangingwall subsidence generated by the normal fault and the regional subsidence or uplift rate. Positive total subsidence obviously increases the accommodation space (e.g. passive margins and back-arc basins), in contrast with negative total subsidence (e.g. orogens). Where the hangingwall subsidence rate is faster than the sedimentation rate in case of both positive and negative total subsidence, the facies and thickness of the syntectonic stratigraphic package may vary from the hangingwall to the footwall. A hangingwall subsidence rate slower than sedimentation rate only results in a larger thickness of the strata growing in the hangingwall, with no facies changes and no morphological step at the surface. The isostatic footwall uplift is also proportional to the amount and density of the sediments filling the half-graben and therefore it should be more significant when the hangingwall subsidence rate is higher than sedimentation rate.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.