Pan-African orogeny

The Pan-African orogeny was a series of major Neoproterozoic orogenic events which related to the formation of the supercontinents Gondwana and Pannotia about 600 million years ago.[1] This orogeny is also known as the Pan-Gondwanan or Saldanian Orogeny.[2] The Pan-African orogeny and the Grenville orogeny are the largest known systems of orogenies on Earth.[3] According to the Rino and co-workers, the sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust.[3]

History and terminology

The term Pan-African was coined by Kennedy 1964 for a tectono-thermal event at about 500 Ma when a series of mobile belts in Africa formed between much older African cratons. At the time, other terms were used for similar orogenic events on other continents, i.e. Brasiliano in South America; Adelaidean in Australia; and Beardmore in Antarctica.

Later, when plate tectonics became generally accepted, the term Pan-African was extended to all of the supercontinent Gondwana. Because the formation of Gondwana encompassed several continents and extended from the Neoproterzoic to the early Palaeozoic, Pan-African could no longer be considered a single orogeny, but rather an orogenic cycle that included the opening and closing of several large oceans and the collisions of several continental blocks. Furthermore, the Pan-African events are contemporaneous with the Cadomian orogeny in Europe and the Baikalian orogeny in Asia, and crust from these areas were probably part of Pannotia (i.e. Gondwana when it first formed) during the Precambrian.[4]

Attempts to correlate the African Pan-African belts with the South American Brasiliano belts on the other side of the Atlantic has in many cases been problematic.[5]

Pan-African belts

West Gondwana with major cratons in brown and Pan-African orogenies in grey

Orogenic belts comprising the Pan-African system include:

References

  1. Glossary.
  2. van Hinsbergen 2011, p. 148
  3. 1 2 Rino, S.; Kon, Y.; Sato, W.; Maruyama, S.; Santosh, M.; Zhao, D. (2008). "The Grenvillian and Pan-African orogens: World's largest orogenies through geologic time, and their implications on the origin of superplume". Gondwana Research. 14: 51–72.
  4. Kröner & Stern 2004, Introduction, p. 1
  5. Frimmel, Hartwig E. (2010). "Configuration of Pan-African Orogenic Belts in Southwestern Africa". In Gaucher, Claudio; Sial, Alcides; Haverson, Galen. Neoproterozoic-cambrian tectonics, global change and evolution: a focus on south western Gondwana. Elsevier. pp. 145–151.
  6. Kröner & Stern 2004, pp. 2–4
  7. Cutten 2002.
  8. Grantham, Maboko & Eglington 2003, p. 417–418.
  9. 1 2 Kröner & Stern 2004, p. 7
  10. Kröner & Stern 2004, pp. 7–8
  11. Kröner & Stern 2004, pp. 8–9
  12. 1 2 Kröner & Stern 2004, p. 9
  13. 1 2 Kröner & Stern 2004, pp. 9–10
  14. Kröner & Stern 2004, p. 10
  15. Kröner & Stern 2004, pp. 10–11

Sources


This article is issued from Wikipedia - version of the 11/6/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.