| Bahariya Formation | |
| Type: | Geological formation |
| Period: | Cenomanian |
| Age: | Early Cenomanian ~ |
| Prilithology: | Sandstone |
| Otherlithology: | Mudstone, siltstone |
| Namedfor: | Bahariya Oasis |
| Namedby: | Said |
| Year Ts: | 1962 |
| Region: | Western Desert |
| Coordinates: | 28.4056°N 28.8056°W |
| Underlies: | El Heiz Fm., El Naqb Fm.[1] |
| Overlies: | Basement |
| Thickness: | ≈100m (300feet) |
The Bahariya Formation (also transcribed as Baharija Formation) is a fossiliferous geologic formation dating back to the early Cenomanian, which outcrops within the Bahariya depression in Egypt, and is known from oil exploration drilling across much of the Western Desert where it forms an important oil reservoir.[2] [3] [4]
The Bahariya Formation forms the base of the depression, the lower part of the enclosing escarpment and all of the small hills within.[5] The type section for the formation is found at Gebel El-Dist, a hill at the northern end of the Bahariya depression.[6]
Four depositional sequences have been recognised in the Bahariya Formation in the Bahariya depression, separated by three sub-aerial unconformities. The formation was deposited during a period of relative rise in sea level, with each unconformity representing a relative fall in sea level.[2] Each of the individual sequences contains sediments deposited under fluvial, shoreline and shallow marine conditions.
| Foraminifera of the Bahariya Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | |||||
| Charentia | C. cuvillieri | |||||
| Favusella | F. washitensis | |||||
| Mayncina | M. orbignyi | |||||
| Rotalipora | R. cushmani R. reicheli | |||||
| Thomasinella | T. aegyptia T. fragmentaria T. punica | |||||
| Whiteinella | W. archaeocretacea | |||||
| Other microorganisms of the Bahariya Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Images | ||||
| Botryococcus | ||||||
| Coronifera | C. oceanica | |||||
| Cyclonephelium | C. edwardsii C. vannophorum | |||||
| Dynopterigium | D. cladoides | |||||
| Exochosphaeridium | ||||||
| Florentinia | F. cooksoniae F. mantlii | |||||
| Kallosphaeridium | ||||||
| Mudrongia | M. simplex | |||||
| Palaeoperidinium | P. cretaceum | |||||
| Pediastrum | ||||||
| Pseudoceratium | P. anaphrisum P. securigerum | |||||
| Scenedesmus | ||||||
| Spiniferites | ||||||
| Subtilisphaera | S. perlucida S. senegalensis | |||||
| Xiphophoridium | X. alatum | |||||
| Molluscs of the Bahariya Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Notes | Images | |||
| Baculites | A heteromorph ammonite with a nearly straight shell. | |||||
| Cardium | A cockle. | |||||
| Exogyra | A reef-forming true oyster associated with solid substrates and warm temperatures. | |||||
| Gastrochaena | A saltwater clam. | |||||
| Neolobites | N. vibrayeanus | A typical rolled ammonite. | ||||
| Nucula | A small saltwater clam. | |||||
| Ostrea | O. flabeata | An edible oyster. | ||||
| Crustaceans of the Bahariya Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Notes | Images | |||
| Amphicytherura | A. sexta | |||||
| Anticythereis | A. gaensis | |||||
| Bairdia | B. bassiounii B. elongata | |||||
| Brachycythere | B. ledaforma porosa | |||||
| Bythoceratina | B. avnonensis B. tamarae | |||||
| Bythocypris | B. eskeri | |||||
| Cythereis | C. algeriana C. bicornis levis C. canteriolata | |||||
| Cytherella | C. ovata C. paenovata C. parallela C. sulcata | |||||
| Fabanella | ||||||
| Looneyella | L. sohni | |||||
| Loxoconcha | L. clinocosta L. fletcheri | |||||
| Metacytheropteron | M. berbericum | |||||
| Ovocytheridea | O. caudata O. producta O. reniformis | |||||
| Paracypris | P. acutocaudata P. angusta P. mdaouerensis P. triangularis | |||||
| Pterygocythere | P. raabi | |||||
| Veeniacythereis | V. jezzineensis | |||||
| Xestoleberis | X. obesa | |||||
Direct fossils are sparse, though plant leaves with extensive damage from folivorous insects have been documented.
| Chondrichthyes of the Bahariya Formation | ||||
|---|---|---|---|---|
| Genus | Species | Abundance | Notes | Images |
| Aegyptobatus | A. kuehnei | A sclerorhynchiform. | ||
| Asteracanthus | A. aegyptiacus | A hybodont shark. | ||
| Baharipristis | B. bastetiae | A sclerorhynchiform. | ||
| Cretodus | C. longiplicatus | A shark. | ||
| Cretolamna | C. appendiculata | A mackerel shark. | ||
| Distobatus | D. nutiae | A sclerorhynchiform. | ||
| Gymnura | G. laterialata | A butterfly ray. | ||
| Haimirichia | H. amonensis | A shark previously classified in the genera Odontaspis, Serratolamna, and Carcharias. | ||
| Isidobatus | I. tricarinatus | A sclerorhynchiform. | ||
| Marckgrafia | M. lybica | A sclerorhynchiform. | ||
| Onchopristis | O. numida | One complete cranium and associated vertebrae. | A sclerorhynchid rajoid. | |
| Peyeria | P. libyca | A sclerorhynchiform. | ||
| Ptychotrygon | P. henkeli | A sclerorhynchiform. | ||
| Renpetia | R. labiicarinata | A sclerorhynchiform. | ||
| Rhinoptera | A batoid ray. | |||
| Schizorhiza | S. stromeri | An unusual sclerorhynchid sawfish that retained its rostral teeth after they were replaced. | ||
| Squalicorax | S. baharijensis | A large shark. | ||
| Scapanorhynchus | S. subulatus | A mitsukurinid similar to the modern goblin shark. | ||
| Squatina | An angelshark. | |||
| Tribodus | T. aschersoni | A hybodont. | ||
| Osteichthyes of the Bahariya Formation | ||||
|---|---|---|---|---|
| Genus | Species | Abundance | Notes | Images |
| Bawitius | B. bartheli | A giant bichir. | ||
| Concavotectum | C. moroccensis | Possibly synonymous with Paranogmius doederleini. | ||
| Ceratodus | A lungfish. | |||
| Coelodus | A pycnodontid. | |||
| Enchodus | One tooth. | A predatory fish. | ||
| Lepidotes | Isolated scales. | Possibly misidentified from Bawitius bartheli. | ||
| Mawsonia | M. lybica | Considered a "signature taxon" of the formation. | A giant freshwater coelacanth. Species assignation deemed provisional due to the lack of neotype. | |
| Neoceratodus | N. africanus | A lungfish related to the living Australian species. | ||
| Palaeonotopterus | P. greenwoodi | Nomen conservandum of the two Plethodus species previously described. | ||
| Paranogmius | Paranogmius doederleini | One vertebra. | Holotype lost in World War II. Could be synonymous with Concavotectum moroccensis. | |
| Plethodus | P. libycus P. tibniensis | Holotypes destroyed in World War II, but now believed to have been misidentified Palaeonotopterus greenwoodi. | ||
| Retodus | R. tuberculatus | A lungfish species identified from remains previously assigned to Neoceratodus. | ||
| Saurodon | Identified by Stromer in 1936, but now rejected due to this genus appearing only in post-Cenomanian Europe and North America. Now listed as Ichthyodectidae incertae sedis. | |||
| Stromerichthys | S. aethiopicus | A predatory bowfin relative. | ||
| Crocodyliformes of the Bahariya Formation | ||||
|---|---|---|---|---|
| Genus | Species | Abundance | Notes | Images |
| Aegyptosuchus | A. peyeri | A poorly known, possibly stomatosuchid crocodile. | ||
| Hamadasuchus | H. rebouli | A terrestrial, dog-like peirosaurid. It is possible that some material previously attributed to Libycosuchus actually belongs to this species. | ||
| Libycosuchus | L. brevirostris | A terrestrial crocodile of uncertain affinities, possibly related to Notosuchus. | ||
| Stomatosuchus | S. inermis | A complete cranium | A large, flat-headed stomatosuchid with multiple small conical teeth, and possibly a pelican-like throat pouch. The only remains were destroyed in World War II. | |
| Stromerosuchus | S. aegyptiacus | Fragmentary remains | Nomen dubium assigned to material found in 1911, that were badly damaged in 1922 while being shipped to Germany for study. Some material may belong to Aegyptosuchus and other to Stomatosuchus. | |
| Sauropods of the Bahariya Formation | ||||
|---|---|---|---|---|
| Genus | Species | Material | Notes | Images |
| Aegyptosaurus | A. baharijensis | Partial postcranial skeleton[8] | A titanosaur of about 15 meters. All remains were destroyed in World War II. | |
| Dicraeosaurus | D. hansemanni | Isolated scapula and vertebra | Identified by Stromer in 1932. Subsequently considered a rebbachisaurid, or a third, unnamed titanosaur. | |
| Paralititan | P. stromeri | Partial postcranial skeleton[9] | One of the largest titanosaurs of the Cretaceous, with a 1.69 meters long humerus and an estimated total length of 26 meters. | |
| Theropods of the Bahariya Formation | ||||
|---|---|---|---|---|
| Genus | Species | Abundance | Notes | Images |
| Abelisauridae indet.[10] | Indeterminate | "MUVP 477, an isolated caudal (tenth) cervical vertebra" | A medium-sized abelisaurid, estimated around 5.77 meters (~18.9 feet) long. The first unambiguous abelisaurid known from the Bahariya Formation. | |
| Bahariasaurus | B. ingens | A medium-sized theropod of uncertain affinities. Possibly a megaraptoran, a relative of Deltadromeus, or both. | ||
| Carcharodontosaurus | C. saharicus | A large carcharodontosaurid allosauroid. | ||
| Elaphrosaurus | E. bambergi | Material now considered to be indeterminate theropod remains. | ||
| Sigilmassasaurus | S. brevicollis | Previously considered a species of Spinosaurus, or a synonym of S. aegyptiacus. | ||
| Spinosaurus | S. aegyptiacus | Most common dinosaur of the formation. | A large spinosaurid. | |
In addition, there are isolated theropod teeth disputedly assigned to dromaeosaurids, or to abelisaurids.
Thirty different genera are known from Bahariya, including megaflora. Much of the material is yet to be described.[11] [12] Other taxa include Sapindales, Piperaceae, Lauraceae, Platanaceae, Magnoliopsida, Nymphaeaceae, Cornaceae, Proteaceae and Vitaceae not identified at genus level; and miospore and pollen species.[13] [14]
| Vascular Plants | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Abundance | Notes | Images | ||
| Agathis / Wollemia[15] | A/W spp. | Few Specimens | An Araucarian conifer, now restricted to Australasia. | |||
| Araliaephyllum? | Indeterminate ("Morphotype-14") | Few Specimens | Suggested to be related with Lauraceae | |||
| Cladophlebis | C. spp. | Few Specimens | Fern Laflets | |||
| Cornophyllum | C. distense | Few Specimens | Suggested to be related with Cornaceae | |||
| Cinnamophyllum? | Indeterminate ("Morphotype-12") | Few Specimens | Suggested to be related with Lauraceae | |||
| Eucalyptolaurus/"Myrtophyllum”(?) | Indeterminate ("Morphotype-08") | Few Specimens | Specimens of the family Lauraceae | |||
| Laurophyllum | L. africanum | Few Specimens | Specimens of the family Lauraceae | |||
| Liriophyllum | L. farafraense | Few Specimens | Specimens of the family Magnoliaceae | |||
| Marsilea | aff. Marsilea spp. | Few Specimens | Water fern. | |||
| Magnoliid |
| Few Specimens | Shows festooned brochidodromous venation | |||
| Magnoliaephyllum |
| Few Specimens | Possible affinities with Lauraceae | |||
| Nelumbites |
| Common occurrence in the lower shale bed | Typical leaves of the faimily Nelumbonaceae | |||
| Paradoxopteris | P. stromeri | Co-Dominant plant | Xerophytic tree fern suggestive of a dry tropical climate. | |||
| Plumafolium? | Indeterminate ("Morphotype-18") | Few Specimens | A Monocot, probably related with Liliopsida | |||
| Rogersia | R. longifolia | Few Specimens | Likely lobes of a much bigger leaf of Sapindopsis type | |||
| Typhaephyllum | cf. T. sp. | Few Specimens | Interpreted as a monocot, probably related to Typhaceae | |||
| Vitiphyllum | V. aff. multifidum | Few Specimens | Some similarities with Pabiania of the family Lauraceae | |||
| Weichselia | W. reticulata | Dominant plant | Xerophytic tree fern suggestive of a dry tropical climate. | |||