Several fossiliferous stratigraphic units in Madagascar have provided fossils, most notably the Maastrichtian Maevarano Formation and the Jurassic Isalo III Formation. The oldest fossil-bearing formations date to ages before the break-up of Madagascar from Africa and India; the units of the Sakoa Group are found in both India and Madagascar, while the Beaufort Group is shared with southern Africa.
The Maevarano Formation is a Late Cretaceous sedimentary rock formation found in the Mahajanga Province of northwestern Madagascar. It is most likely Maastrichtian in age, and records a seasonal, semiarid environment with rivers that had greatly varying discharges. Notable animal fossils recovered include the theropod dinosaur Majungasaurus, the early bird Vorona, the paravian Rahonavis, the titanosaurian sauropod Rapetosaurus, and the giant frog Beelzebufo.
The Berivotra Formation is a Maastrichtian sedimentary formation of the Mahajanga Basin in Boeny, Madagascar. The claystones of the formation were deposited in a shallow marine environment. The Berivotra Formation overlies the fossil-rich Maevarano Formation, in which more fossils of Beelzebufo, also recovered from the Berivotra Formation, have been found. Many shark and ray teeth were collected by surface prospecting on outcrops of the Berivotra Formation, which is readily distinguished by its yellowish grey to pale olive colour, as opposed to the white and green fluvial sandstones that form the upper 15 to 20 metres of the underlying Maevarano Formation.
The Isalo III Formation is a geological formation in Madagascar, off the eastern coast of Africa. It dates back to the Middle Jurassic. The use of the term "Isalo III" is somewhat controversial as the two prior units Isalo I and II are Triassic cross-bedded sandstone units that form a continuous depositional sequence, while the "Isalo III" sandstones are not part of the same depositional sequence, and were deposited considerably later. and are perhaps better treated as part of several separate formations. It is traditionally divided into two subunits the lower, Bajocian aged Isalo IIIa unit also known as the Beronono Formation and the upper, Bathonian aged Isalo IIIb unit also known as the Sakaraha Formation or Sakahara Formation. The Sakaraha Formation consists of sandstones, marls and carbonates and represents a coastal plain environment, and is laterally equivalent to the predominantly carbonate Bemaraha Formation, which represents a coastal barrier lagoon complex. The formation is found in the northwest and in the southeast of the country and has provided a variety of fossils.
The Tiourarén Formation is a geological formation in the Agadez Region of Niger whose strata were originally thought to be Early Cretaceous. However, re-interpretation of the sediments showed that they are probably Middle or Late Jurassic (Bathonian-Oxfordian) in age. Other works suggested it reaches the Barremian. It is the uppermost unit of the Irhazer Group. Dinosaur remains & other vertebrates are among the fossils that have been recovered from the formation. Originally part of the "Argiles de l'Ihrazer", the Tiouaren Formation primarily comprises reddish to purple siltstones with occasional marls, limestones, and scarce channel sandstones.
The Dukamaje Formation is a geological formation in Niger and Nigeria whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation. A wealth of Mosasaur fossils have also been recovered from this formation, particularly from the area around Mt. Igdaman.
The Ankarafantsika Formation is a Late Cretaceous (Cenomanian) geologic formation of the Mahajanga Basin in the Boeny region of Madagascar, Africa. The fine-grained sandstones of the formation were deposited in a fluvial to lacustrine environment.
The Ankazomihaboka Formation is a Coniacian geologic formation in the Mahajanga Basin of northwestern Madagascar. The formation comprises claystones and sandstones deposited in a fluvial to lacustrine environment. The formation is overlain by the Marovoay Beds and overlies basalt.
The Irhazer Shale or Irhazer II Formation is a Middle Jurassic geologic formation of the Irhazer Group in the Agadez Region of Niger. Fossil ornithopod tracks have been reported from the formation. The dinosaur Spinophorosaurus is known from the formation.
The Etjo Sandstone is an Early Jurassic geologic formation in northern Namibia. The formation overlies the Omingonde Formation in the Waterberg Basin and the Doros and Gai-As Formations in the Huab Basin and has a total thickness of 140 metres (460 ft). Fossil theropod tracks of Prosauropoda indet., Theropoda indet., Tetrapodium elmenhorsti, Saurichnium anserinum, S. damarense, S. parallelum and S. tetractis have been reported from the formation, deposited in an aeolian environment.
The Moskvoretskaya Formation is a Middle Jurassic geologic formation in the European part of Russia. It consists of continental claystones, siltstones and sandstones deposited in karstified segments of underlying Middle Carboniferous limestone, that would have formed underground aquifers.
The Kandreho Formation is an Early Jurassic geological formation of the Mahajanga Basin of Madagascar. The marly limestones of the formation were deposited in a subtidal lagoonal environment. The formation overlies the Bouleiceras and Spiriferina beds of the early Toarcian and has been correlated to the Marrat Formation of Saudi Arabia. Fossils of the marine crocodylian "Steneosaurus" as well as bivalves and the ammonite Nejdia have been found in the formation. The name Kandreho Formation was proposed by Geiger in 2004.
The Bemaraha Formation is a Middle Jurassic geological formation of the Morondava Basin of Madagascar. The lime mudstones, grainstones and limestones of the formation were deposited in lagoonal and reefal environments. Fossils of groups of invertebrates and theropod and sauropod tracks have been found in the formation. The Sahalaly River tracksite yielded a single trackway belonging to a quadrupedal dinosaur, possibly a sauropod. Sauropod tracks are rare, making up as little as 1 percent of the present sample. The best-preserved tracks are assigned to the ichnogenus Kayentapus.
Fossiliferous stratigraphic units of the countries and dependencies of Africa | ||
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