Quaternary coral reefs of the Red Sea coast, Egypt: diagenetic sequence, isotopes and trace metals contamination

Journal Article

مستخلص المنشور

This study focuses on the diagenetic sequence under
marine and meteoric conditions as well as isotopes and
trace metals contamination in Quseir and Gebel Zeit areas
along the Egyptian Red Sea coast through a series of modern
and fossil corals, Porites lutea and Favites pentagona. The
diagenetic sequence begins with deposition of thin fringes of
syntaxial aragonite and micritic high-magnesian calcite
in the modern corals to completely altered Porites and
partially altered Favites to low-magnesium calcite in the oldest
Pleistocene unit. Average δ18O and δ13C values of
Pleistocene corals in the two studied areas were lower than
those of modern corals. Values of modern corals and lower
fossil unit indicated coralline limestone, while those of middle
and upper fossil units indicated fresh water influences.
Average values of trace metals in modern corals were higher
than those of Pleistocene counterpart except for Mn. Modern
coral samples recorded enrichment in the average values of
Pb, Zn, and Mn at Quseir area and enrichment in Co, Cu, and
Ni at Gebel Zeit area. This may be attributed mostly to
different tourist activities, landfill due to increase urbanization
and nearby of Quseir area from the old phosphate harbor at El
Hamrawin area, as well as oil exploration and production
activities in the Gulf of Suez area. Also, results indicated that
most samples of Porites have high concentration of trace
metals than in Favites, especially in Cu, Zn, Mn, and Pb.
This may due to high amounts of intergranular porosity and
high total surface area of Porites in contrast to Favites.