Abstract Palynological and palynofacies analyses were
carried out on some Cretaceous samples from the Qattara
Rim-1X borehole, north Western Desert, Egypt. The
recorded palynoflora enabled the recognition of two informal
miospore biozones arranged from oldest to youngest as
Elaterosporites klaszii-Afropollis jardinus Assemblage
Zone (mid Albian) and Elaterocolpites castelainii–
Afropollis kahramanensis Assemblage Zone (late Albian–
mid Cenomanian). A poorly fossiliferous but however, datable
interval (late Cenomanian–Turonian to ?Campanian–
Maastrichtian) representing the uppermost part of the studied
section was also recorded. The palynofacies and visual
thermal maturation analyses indicate a mature terrestrially
derived organic matter (kerogen III) dominates the sediments
of the Kharita and Bahariya formations and thus these
two formations comprise potential mature gas source rocks.
The sediments of the Abu Roash Formation are mostly
dominated by mature amorphous organic matter (kerogen
II) and the formation is regarded as a potential mature oil
source rock in the well. The palynomorphs and palynofacies
analyses suggest deposition of the clastics of the Kharita and
Bahariya formations (middle Albian and upper Albian–middle
Cenomanian) in a marginal marine setting under
dysoxic–anoxic conditions. By contrast, the mixed clasticcarbonate
sediments of the Abu Roash Formation (upper
Cenomanian–Turonian) and the carbonates of the Khoman
Formation (?Campanian–Maastrichtian) were mainly deposited
in an inner shallow marine setting under prevailing
suboxic–anoxic conditions as a result of the late Cenomanian
and the Campanian marine transgressions. This environmental
change from marginal to open (inner shelf) basins reflects the
vertical change in the type of the organic matter and its
corresponding hydrocarbon-prone types. A regional warm
and semi-arid climate but with a local humid condition developed
near/at the site of the well is thought to have prevailed.