Just as 30° separate main topography of the world at equator today, a 30° pattern can be recognized of Pangea 200 million years ago. The convection currents must then have been coupled and de-coupled in a favorable way so that breakup of the tectonic plate could take place. The breakup occurs mainly along the main division lines of lower mantle large scale convection rolls as shown here.
It is notable that Iceland during that time was located over a large scale downwelling line (the third from left in the drawing). During the breakup, the area where Iceland is now located moved westwards over to the next division line, namely the upwelling line of the center of the present location of the Atlantic Ocean.
.https://en.wikipedia.org/wiki/Pangaea
To clarify further, what has happened after the break-up of Pangea, you can have a look at this drawing of the equatorial plane of the Earth, showing the convection rolls pattern.
To compere with upper drawing, The red marking here corresponds to the second line of the world map above. The upwelling division line did break S-America away from Africa, and then S-America drifted directly westwards over to the other convection roll. The same happened to Africa, but it also drifted northwards, so that now it only spans 30° from east to west. The northwards, and more irregular drift also led to the fact that the coastline is slightly east of the division line, leading to the formation of the Great Rift Valley over the corresponding upwelling large scale division line.
It is interesting that Indonesia has not altered its position according to the map from Wikipedia shown above. The equatorial pattern of 30° intervals is therefore maintained for both 200 Ma and present. For clarity, this drawing can therefore be added:
This is how it looks with 200 million years interval. It would have been nice if we could have measured the drift step by step when the Atlantic Ocean was getting wider at equator. That process is of course still ongoing in general. We can measure the tectonic drift every day now, so this should not be a mystery to be solved. The puzzle of Pangea has been reconstructed accurately because we have thousands of high quality measurements to rely on. Therefore, these two cross sections of equator can be drawn.
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