Abstract
The present study deals with microfacies analysis, paleoecology and sequence stratigraphy of the Lower–Middle Eocene
rocks in central Nile Valley and west-central Sinai. Four rock units were marked (Minia, Darat, Samalut and Maghagha
formations). Eight facies belts were interpreted including lagoon, back bank, main bank, fore bank and open marine outer
bank facies and deposited on a gently dipping platform ramp. This ramp might be further divided to three main faunal
associations depending on the depth of the water and associated fauna. Four major depositional sequences (DS1–DS4),
refecting third-order cycles and separated by two prominent sequence boundaries (SB1 and SB2) were marked. The record
of these sequences refects the changes in eustatic sea level plus the regional tectonism in the area. Every sequence includes
facies associations, which constitute lowstand and/or transgressive and highstand systems tracts. Based on faunal elements
and facies analysis, the water salinity, water temperature, nutrients, substrate, water depth and hydrodynamic behavior were
discussed. The fne-grain size of the deposits, the loss of good connectedness and the occluding of the Nummulitetests by
other minerals could give rise to low reservoir potential. The sedimentation was afected by the tectonic activity of the Syrian
orogeny. Moreover, both external and internal mechanisms have controlled the carbonate sedimentation, basin construction
and sequence bounding surfaces