African Plate
African Plate | |
---|---|
Type | Major |
Approximate area | 61,300,000 km2 (23,700,000 sq mi)[1] |
Features | Africa, Atlantic Ocean, Mediterranean Sea, Red Sea |
The African Plate, also known as the Nubian Plate, is a
Between 60 million years ago and 10 million years ago, the
Boundaries
The western edge of the African Plate is a
Components
The African Plate includes several
The Saharan Metacraton has been tentatively identified as the remains of a craton that has become detached from the subcontinental lithospheric mantle, but alternatively may consist of a collection of unrelated crustal fragments swept together during the Pan-African orogeny.
In some areas, the cratons are covered by sedimentary basins, such as the Tindouf Basin, Taoudeni Basin and Congo Basin, where the underlying archaic crust is overlaid by more recent Neoproterozoic sediments. The plate includes shear zones such as the Central African Shear Zone (CASZ) where, in the past, two sections of the crust were moving in opposite directions, and rifts such as the Anza Trough where the crust was pulled apart, and the resulting depression filled with more modern sediment.
Modern movements
The African Plate is rifting in the eastern interior of the African continent along the East African Rift. This rift zone separates the African Plate to the west from the Somali Plate to the east. One hypothesis proposes a mantle plume rising beneath the Afar region pushing the crust outward, whereas an opposing hypothesis explains the rifting by dynamics in the crust, as a break in the African Plate along a line of maximum weakness as plates to its east move rapidly northward.
The African Plate's speed is estimated at around 2.15 cm (0.85 in) per year.[4] It has been moving over the past 100 million years or so in a general northeast direction. It is pushing closer to the Eurasian Plate, causing subduction where oceanic crust is converging with continental crust (e.g. portions of the central and eastern Mediterranean). In the western Mediterranean, the relative motions of the Eurasian and African plates produce a combination of lateral and compressive forces, concentrated in a zone known as the Azores–Gibraltar Fault Zone. Along its northeast margin, the African Plate is bounded by the Red Sea Rift where the Arabian Plate is moving away from the African Plate.
The New England hotspot in the Atlantic Ocean has probably created a short line of mid- to late-Tertiary age seamounts on the African Plate but appears to be currently inactive.[5]
References
- ^ "Sizes of Tectonic or Lithospheric Plates". About.com. Archived from the original on 5 June 2016. Retrieved 30 June 2015.
- ^ "Somali Plate". Ashten Sawitsky. Retrieved 30 June 2015.
- S2CID 4403043.
- ^ Huang, Zhen Shao (1997). "Speed of the Continental Plates". The Physics Factbook. Retrieved 7 June 2018.
- .
External links
- USGS - Understanding plate motions
- Meijer, P. Th.; Wortel, M. J. R. (1999). "Cenozoic dynamics of the African plate with emphasis on the Africa-Eurasia collision". Journal of Geophysical Research: Solid Earth. 104 (B4): 7405–7418. .