Running time backwards
Regime 4, the current regime, is shown with green transforms. A triple junction in the central part of the ocean separates three plates: Africa, Antarctica and Indo-Australia. This regime has been operating since about 43 Ma.
Regime 3 was its predecessor. Once ocean crust created during Regime 4 is removed, the transforms of Regime 3 (yellow) are re-united. Regime 3 was the time (89-43 Ma) in which India made a rapid northward movement of about 4500 km. By the time this is undone, India lies somewhat south of Madagascar and the transforms of Regime 2 are re-united.
Regime 2 transforms are shown in white. During their creation (140-89 Ma) Australia-Antarctica rotated clockwise away from India and South America started westwards away from Africa with creation of the South Atlantic Ocean (not shown here in detail).
Regime 1 (140 to 200 Ma) occupies much of the Jurassic period of geological time. The Indian Ocean was in its infancy and Gondwana existed in just two fragments, South America and Africa to the west and Madagascar, India, Antarctica and Australia to the east. The modest transforms of this period are shown in pink. By the time we reach 200 Ma, the two parts of Gondwana are quite closely re-united and North America lies off the northwest coast of Africa.
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