The Bahariya Formation (also transcribed as Baharija Formation) is a

fossiliferous A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

dating back to the early

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

, which outcrops within the Bahariya depression in

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

, and is known from oil exploration drilling across much of the Western Desert where it forms an important oil

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

.Weishampel, David B; et al (2004). "Dinosaur distribution (Late Cretaceous, Africa)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 604. .

Extent

The Bahariya Formation forms the base of the depression, the lower part of the enclosing escarpment and all of the small hills within. The

type section A stratotype or type section in geology is the physical location or outcrop of a particular reference exposure of a stratigraphic sequence or stratigraphic boundary. If the stratigraphic unit is layered, it is called a stratotype, whereas the stan ...

for the formation is found at Gebel El-Dist, a hill at the northern end of the Bahariya depression.

Stratigraphy and sedimentology

Four depositional sequences have been recognised in the Bahariya Formation in the Bahariya depression, separated by three sub-aerial

unconformities An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

. The formation was deposited during a period of relative rise in sea level, with each unconformity representing a relative fall in sea level. Each of the individual sequences contains sediments deposited under

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

, shoreline and shallow marine conditions.

Flora

Thirty different genera are known from Bahariya, including

megaflora Megaflora (from Greek μέγας ''megas'' "large" and New Latin ''flora'' "plant life") refers to an exceptionally large plant species. Examples of megaflora include the Sequoioideae of California and a number of extinct plant species from the M ...

. Much of the material is yet to be described.Ijouhier, Jamale (2016) A reconstruction of the palaeoecology and environmental dynamics of the Bahariya Formation of Egypt. ''PeerJ Preprints'', https://doi.org/10.7287/peerj.preprints.2470v1 Other taxa include

Sapindales Sapindales is an order of flowering plants. Well-known members of Sapindales include citrus; maples, horse-chestnuts, lychees and rambutans; mangos and cashews; frankincense and myrrh; mahogany and neem. The APG III system of 2009 includes it ...

Piperaceae The Piperaceae (), also known as the pepper family, are a large family of flowering plants. The group contains roughly 3,600 currently accepted species in 5 genera. The vast majority of species can be found within the two main genera: ''Piper'' ( ...

Lauraceae Lauraceae, or the laurels, is a plant family that includes the true laurel and its closest relatives. This family comprises about 2850 known species in about 45 genera worldwide (Christenhusz & Byng 2016 ). They are dicotyledons, and occur ma ...

Platanaceae Platanaceae, the "plane-tree family", is a family of flowering plants in the order Proteales. The family consists of only a single extant genus ''Platanus'', with eight known species. The plants are tall trees, native to temperate and subtropic ...

Magnoliopsida Magnoliopsida is a valid botanical name for a class of flowering plants. By definition the class will include the family Magnoliaceae, but its circumscription can otherwise vary, being more inclusive or less inclusive depending upon the classif ...

Nymphaeaceae Nymphaeaceae () is a family of flowering plants, commonly called water lilies. They live as rhizomatous aquatic herbs in temperate and tropical climates around the world. The family contains nine genera with about 70 known species. Water li ...

Cornaceae The Cornaceae are a cosmopolitan family of flowering plants in the order Cornales. The family contains approximately 85 species in two genera, ''Alangium'' and ''Cornus''. They are mostly trees and shrubs, which may be deciduous or evergreen, alt ...

Proteaceae The Proteaceae form a family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genera with about 1,660 known species. Together with the Platanaceae and Nelumbonaceae, they make up the order Pro ...

and

Vitaceae The Vitaceae are a family of flowering plants, with 14 genera and around 910 known species, including common plants such as grapevines (''Vitis'' spp.) and Virginia creeper (''Parthenocissus quinquefolia''). The family name is derived from the ge ...

not identified at genus level; and miospore and

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

species.

Microfauna Microfauna (Ancient Greek ''mikros'' "small" + New Latin ''fauna'' "animal") refers to microscopic animals and organisms that exhibit animal-like qualities. Microfauna are represented in the animal kingdom (e.g., nematodes, small arthropods) and t ...
and
Meiofauna Meiobenthos, also called meiofauna, are small benthic invertebrates that live in both marine and fresh water environments. The term ''meiofauna'' loosely defines a group of organisms by their size, larger than microfauna but smaller than macrof ...

Foraminifera

Other microorganisms

Invertebrates

Molluscs

Crustaceans (Ostracoda)

Insects

Direct fossils are sparse, though plant leaves with extensive damage from

folivorous In zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less energy than other types of foods, and often toxic compounds.Jones, S., Martin, R., & Pilbeam, D. (1 ...

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

s have been documented.

Vertebrates

Cartilaginous fish

Bony fish

Testudines

Squamates

Plesiosaurs

Crocodyliformes

Pterosaurs

Sauropods

Theropods

In addition, there are isolated theropod teeth disputedly assigned to

dromaeosaurid Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...

s, or to

abelisaurid Abelisauridae (meaning "Abel's lizards") is a family (or clade) of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are foun ...

References

{{reflist Geologic formations of Egypt Upper Cretaceous Series of Africa Sandstone formations Mudstone formations Siltstone formations Fluvial deposits Shallow marine deposits Paleontology in Egypt