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QUATERNARY TRAVERTINES OF WADIS ABU HAD-DIB AREA, EASTERN DESERT, EGYPT: PALEOENVIRONMENT THROUGH FIELD, SEDIMENTOLOGY, AGE AND ISOTOPIC STUDY
MOHAMED ABD ELRAHMAN HAMDAN

 Dept Geology, Fac. Sciences, Cairo Univ., Giza, Egypt.

Three travertine units and four gravel units are exposed unconformably over the Basement
rocks in the occurrence here studied. The oldest travertine (T1) is of cascaded type, exposed in Wadi Dib ab.7-10 ms above its present floor. The travertine is associated with gravel unit (G2) and exhibits U/Th dating of 160±20-165±17 Ka.
The second travertine is of fan type, exposed in the western mouth of Wadis Abu Had and Dib. It (T2) has U/Th dating of ab. 45±2-64±6 Ka. These travertine deposits are intertongued with the Middle gravel unit (G3). The youngest lake travertine (T3), exposed on the plain W of Gebel Sufr Abu Had exhibits U/Th dating of ab. 18±0.3-20±0.3Ka.
Oxygen isotope ratios in all samples vary over a relatively narrow range (?18O 17.9-25.39‰) all over ages, suggesting that waters (of similar composition) deposited the travertines at similar temperatures. Cascaded travertine (T1) has ? 13C from -6,12 to -6.33 ‰ and ? 18O from 23.94 to 35.4 ‰, fan travertine has ? 13C from -4.1 to -7.9 ‰, and ? 18O values from 18.38 to 25.14‰, lake travertine yielded ? 13C values from - 1.25 to 5.46 ‰, and ? 18O from 17.39 to 25.52‰. The calculated isotopic temperatures vary from -O.70C 60 9.60C. This relatively cold condition may indicate that the travertines were formed during the last stage of the European glacial periods. The close similarity of the isotopic composition between the travertine of Wadis Abu Had-Dib and that of the Bet Shean may indicate that the Eastern Desert of Egypt and most probably Sinai were part of the Levant climatic system.
The mode of formation of the travertine varied from type to another. The cascaded travertine was formed in vicinity of water fall and perhaps spring (?) and the algae played the main role in its formation. The fan travertine was formed within alluvial fan environment and the higher plant vegetation played the main role in its formation. The lake travertine was formed in shallow lakes and the evaporation played the important role in its formation.