Science Fiction: Alternative Earth

Last week I showed modern nations drawn onto the Pangaea supercontinent as an example of an alternative Earth for SF authors and game designers. In this blog I want to develop the theme and show some more alternative Earths.

About 175m yrs bp in the middle of the age of dinosaurs Pangaea started to break up. The vast bay of the Sea of Tethys in the east extended and broke Pangaea into two supercontinents, Laurasia in the northern hemisphere and Gondwana in the southern hemisphere.

This world is an interesting variant on the modern Earth if these supercontinents failed to break up. Hominids evolved in Africa so would presumably have been restricted to the southern hemisphere until the 15th C. and the invention of the trans-oceanic sailing ship. What would our bold mariners and explorers find on the northern continent?

In the next phase towards the end of the age of dinosaurs, Laurasia rifts along the line of what will be the North Atlantic and rotates clockwise. The world looked something like this.


Finally Gondwana rifts, spinning off South America, Antarctica, India and Arabia leaving Africa as the remaining rump. However the interesting thing is the split started along the line of the African Rift Valley but this spreading zone was overtaken by the ones that gave rise eventually to the South Atlantic.

But it needn't have happened that way. Suppose the African Rift had remained primary? In that case the modern world might look something like this and have a very different spread of climates.