PETROGRAPHY, GEOCHEMISTRY AND DEPOSITIONAL ENVIRONMENTS OF THE UPPER CRETACEOUS- EARLY EOCENE CARBONATES, SOUTHWEST THEMED AREA, EAST CENTRAL SINAI, EGYPT ABDEL AZIZ A. ABDEL AZIZ Geology. Dept., Fac. Sciences, El Minia Univ., Egypt.  Petrographic and geochemical studies of the Upper Cretaceous-Early Eocene succession exposed at south-west Themed in east central Sinai were carried out to interpret their depositional environments and to discuss their diagenetic processes. Two lithological columnar sections at Wadi El Kebashyi and south Gabal El- Ghoriya, southwest Themed area are measured, described and sampled Stratigraphically. the studied sections comprise four formations, from base to top: Themed Formation (Coniacian-Santonian). Sudr Formation (Campanian-Maastrichtian). Esna Shale Formation (Maastrichtian-Paleocne) and Thebes Formation (Early Eocene). Six micofacies types have been recognized in the studied carbonates and compared with the world wide standard ones (SMF). They correspond to standard facies zones 3, 5, 6. 7 and 8 platform facies Their depositional environments are represented by the depositional pattern of shallow marine to deep marine conditions suggesting upward deepening with relatively low water energy conditions and low  sedimentation rate. The sediments of Themed Formation were probably deposited in shallow subtidal marine environment with some restricted conditions in the southern parts. Then the sea level began to raise gradually developing deeper marine conditions during the deposition of the Sudr Formation. On the other hand, the sediments of the Esna Shale and Thebes formations were deposited in deep marine environment below the water wave base, where the sea reached its climax. It is believed that the deposition was largely controlled by long term transgressive phase, with some occasional sea level fluctuations and syn-sedimentary tectonic events. After their deposition. the studied carbonates were subjected to submarine and subaerial diagenetic environments. This is clearly manifested by various diagenetic features such as micritization. Cementation, neomorphism, dolomitization, compaction and ferrugination. The chemical analysis of some major oxides and trace elements reveals that the chemical composition reflects variation in both the depositional environments and the diagenetic processes.