List of fossiliferous stratigraphic units in Madagascar

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Fossiliferous stratigraphic units in Madagascar
Green pog.svg Cretaceous
Blue pog.svg Jurassic
Pink ff0080 pog.svg Triassic
Red pog.svg Permian

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.

Contents

GroupFormationPeriodNotes
Berivotra Formation Maastrichtian [1]
Maevarano Formation Maastrichtian [2]
Ankazomihaboka Formation Coniacian [3]
Ambolafotsy Formation Turonian [4]
Ankarafantsika Formation Cenomanian [5]
Kandreho Formation Middle or Late Toarcian [6]
Bemaraha Formation Early Bajocian-Early Bathonian [7]
Isalo Group Isalo III Formation Bajocian-Bathonian [8]
Isalo II Formation Ladinian-Carnian [9]
Sakamena Group Middle Sakamena Formation Induan [10]
Lower Sakamena Formation Capitanian-Wuchiapingian [11]
Beaufort Group Capitanian [12]
Sakoa Group Sakoa Formation Sakmarian-Artinskian [13]
Karharbari Formation Sakmarian-Artinskian [14]
Talchir Formation Asselian-Sakmarian [15]

See also

Related Research Articles

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 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 Jurassic (Bathonian) in age. It is the uppermost unit of the Irhazer Group. Dinosaur remains are among the fossils that have been recovered from the formation.

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.

<span class="mw-page-title-main">Etjo Sandstone</span>

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.

<span class="mw-page-title-main">Charmouth Mudstone Formation</span> Geological formation in England

The Charmouth Mudstone Formation is a geological formation in England, dating to the Early Jurassic (Sinemurian–Pliensbachian). It forms part of the lower Lias Group. It is most prominently exposed at its type locality in cliff section between Lyme Regis and Charmouth but onshore it extends northwards to Market Weighton, Yorkshire, and in the subsurface of the East Midlands Shelf and Wessex Basin. The formation is notable for its fossils, including those of ammonites and marine reptiles and rare dinosaur remains. The formation played a prominent role in the history of early paleontology, with its Lyme Regis-Charmouth exposure being frequented by fossil collectors including Mary Anning.

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 Andrianavoay 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.

References

  1. Berivotra Formation at Fossilworks.org
  2. Maevarano Formation at Fossilworks.org
  3. Ankazomihaboka Formation at Fossilworks.org
  4. Ambalofotsy Formation at Fossilworks.org
  5. Ankarafantsika Formation at Fossilworks.org
  6. Kandreho Formation at Fossilworks.org
  7. Bemaraha Formation at Fossilworks.org
  8. Isalo III Formation at Fossilworks.org
  9. Isalo II Formation at Fossilworks.org
  10. Middle Sakamena Formation at Fossilworks.org
  11. Lower Sakamena Formation at Fossilworks.org
  12. Toliara at Fossilworks.org
  13. Sakoa Formation at Fossilworks.org
  14. Karharbari Formation at Fossilworks.org
  15. Talchir Formation at Fossilworks.org

Further reading