Liquefaction-induced structures, Hammam Faroun Block, Gulf of Suez rift, Egypt: possible rift-related Neogene seismites

A pre-rift Upper Cretaceous succession records evidence of a localized liquefaction at the eastern side of the Gulf of Suez rift, Egypt. Structurally controlled clastic intrusions, slump-like folds and megabreccia are the common liquefaction-induced structures. The sandstone dykes taper upward with no exposed feeder, and are oriented parallel to and along rift-related conjugate normal faults. The slumps are localized, spatially related to rift-related faults, and preserved within mudstone-dominated layers with more competent sandy shale interbeds. The megabreccias are chaotic, and stretched sporadically along the footwall of a rift-related fault. Meteorite impact, explosive volcanicity, and storm wave actions are excluded as trigger mechanisms. Recent and paleo-earthquake records show that the Neogene Gulf of Suez rift is a seismically active belt with a southward increase in seismic activity. Tectonic-related seismic activity is suggested as a plausible trigger for the liquefaction. Movement along rift-related faults during Oligo-Miocene times might have triggered earthquakes that produced the paleo-seismites.

Automated summary

A localized liquefaction event in the pre-rift Upper Cretaceous succession was observed at the eastern side of the Gulf of Suez rift, Egypt. The structures induced by the liquefaction include structurally controlled clastic intrusions, slump-like folds, and megabreccia. Tectonic-related seismic activity is suggested as the plausible trigger for the liquefaction.