Alfred Wegener in 1912 first of all propounded the theory of continental drift.

The major plates are as follows :
(i) Antarctica and the surrounding oceanic plate
(ii) North American (with western Atlantic floor separated from the South American plate along the Caribbean islands) plate
(iii) South American (with western Atlantic floor separated from the North American plate along the Caribbean islands) plate
(iv) Pacific plate
(v) India-Australia-New Zealand plate
(vi) Africa with the eastern Atlantic floor plate
(vii) Eurasia and the adjacent oceanic plate.

Zone of divergence are boundaries along which plate is composed of mainly oceanic crust.