The development of a tidal-dominated estuary above the Basal Messinian incision in the Lower
Messinian Qawasim Formation in the onshore East Nile Delta province is interpreted from 3D seismic
core, borehole images, and wireline logs data from four selected wells. Sedimentologically in terms of five
facies associations of the Qawasim Formation are; tidally influenced fluvial channels, overbank muds,
estuarine tidal channel, estuarine tidal bars and estuarine muds. These facies associations are building
blocks for the depositional model that bounded by two incisions during the Early Messinain time. The
lower cycle is called Qawasim level I which contains fluvial channel encased in overbank muds of fluvial
plain. The upper cycle, Qawasim level II is characterized by estuarine tidal channel, estuarine tidal bars,
and estuarine muds. The geomorphological characteristics of Qawasim Formation (lower and upper
levels) can be detected using detailed seismic interpretations. The sedimentological and seismic
characteristics of the Qawasim Formation in El Basant field may indicate the depositions in a tidal regime
within estuary domain.