New investigations of petrographic and geochemical characteristics of Mesozoic sandstones from the northwestern Gulf of
Suez in Egypt have been undertaken, documenting dominance of quartzose sandstones containing on average ~ 5% of mostly
sedimentary and subordinately metamorphic lithic fragments (siltstone, sandy siltstone, and, more rarely slate, metasiltstone,
limestone, dolostone, quartz-muscovite schist, and gneiss). These sandstones are depleted in many chemical elements and
display low Al2O3/
SiO2 and K2O/
Na2O ratios. Mineralogical and geochemical parameters point at extensive recycling from
older (i.e., Paleozoic) siliciclastic strata. Relatively constant composition throughout the Mesozoic contrasts with successive
palaeogeographic changes associated to the major events of rifting and dispersal, which may be explained by the widespread
distribution of Paleozoic clastic wedges all across northern Gondwana. |
