Normal Fault
Population Evolution
and Stratigraphic Response: An Example from the Hammam Faraun
Fault
Block, Suez
Rift, Egypt
By
Rob Gawthorpe1, Ian Sharp2, Adel R Moustafa3, Chris Jackson1, Chris Leppard1, Mike Young1
(1) University of Manchester, Manchester, United Kingdom (2) Norsk Hydro ASA, Bergen, Norway (3) Ain Shams University, Cairo, Egypt
The evolution and linkage of fault
segments to form continuous,
basin-bounding normal
fault
zones is recognised as a first-order control on the
size, shape and stratigraphy of sedimentary basins within areas of continental
extension. We present results of an integrated structural and sedimentological
study of the late Oligocene-Recent evolution of the Hammam Faraun
fault
block,
Suez rift that allows the temporal evolution of
fault
populations to be
investigated. Initial
fault
activity was distributed across the
fault
block on
short (1-4 km long), low displacement (<1 km) segments, with most faults
attaining their maximum length soon after the onset of rifting. Over the first
6-8 Myr of rifting, these initial segments either linked to form longer,
segmented
fault
zones, or became inactive and died. Following this rift
initiation phase, displacement became progressively localised onto >25 km long
border
fault
zones bounding the
fault
block and many of the early intra-block
fault
zones became inactive. The locus of
fault
activity continued to migrate
following linkage, with post Middle Miocene displacement focused on the western
margin of the
fault
block. The dynamics of
fault
population evolution
illustrated here are comparable to those suggested by analogue and numerical
modelling studies and have important implications for the tectono-stratigraphic
evolution of rifts and for understanding complex and often subtle syn-rift plays
and structural compartmentalization of major
fault
blocks.