| Somali plate | |
|---|---|
 | |
| Type | Minor |
| Approximate area | 16,700,000 km2[1] |
| Movement1 | south-east |
| Speed1 | 6 mm/year |
| Features | East Africa,Horn of Africa,Gulf of Aden,Socotra Archipelago,Madagascar,Indian Ocean |
| 1Relative to theAfrican plate | |
TheSomali plate is aminor tectonic plate which straddles theEquator in theEastern Hemisphere. It is currently in the process of separating from theAfrican plate along theEast African Rift Valley and moving to the Indian subcontinent. It is approximately centered onthe island of Madagascar and includes about half of the east coast of Africa, from theGulf of Aden in the north through the East African Rift Valley. The southern boundary with the Nubian–African plate is a diffuse plate boundary consisting of theLwandle plate.[2]
TheArabian plate diverges to the north forming theGulf of Aden. TheIndian plate,Australian plate, andAntarctic plate all diverge from the Somali plate forming the easternIndian Ocean. The Somali-Indian boundary spreading ridge is known as theCarlsberg Ridge. The Somali-Australian boundary spreading ridge is known as theCentral Indian Ridge. The Somali-Antarctic boundary spreading ridge is known as theSouthwest Indian Ridge. The western boundary with theAfrican plate is diverging to form theEast African Rift, which stretches south from thetriple junction in theAfar depression. The southern boundary with the Nubian–African plate is a diffuse plate boundary with theLwandle plate.[2] TheSeychelles and theMascarene Plateau are located northeast of the Madagascar.
From1.4–1.2Ga theKibaran orogeny fused the Tanzanian and Congo cratons.[3] From 1000 to 600 Ma the super-continentGondwana was formed and the Pan-Africanorogeny sutured the Tanzanian and Kalaharicratons.[3] Therifting of Gondwana occurred from 190 Ma to 47 Ma separating Madagascar from the eastern coast of Africa and placing theSeychelles/Mascarene Plateau northeast of Madagascar.[4][5] The rifting of the Red Sea started around30 million years ago and the first rifting occurred in the northern West African Rift System around20 million years ago.[6]
