South America and Africa once tore apart and formed an oceanic crust. Its evidence lies in Angola

A research team from the Southern Methodist University (SMU) have discovered rocks and fossils in Angola which speak about how South America and Africa tore apart nearly 140 million years ago and led to the formation of the South Atlantic Ocean.

The team found the rocks and fossils which belonged to the long-extinct marine reptiles in Angola.

According to the research team, the southern coast of Angola is filled with the most complete geological record of the breaking of the two continents and the coming up of the South Atlantic Ocean.

The scientists found the fossils and rocks which dated back from 71 million years to 130 million years ago. 

SMU professor emeritus of Earth Sciences and lead author of the study Louis L Jacobs said, “There are places that you can go to in South America, for instance, where you can see this part of the split or that part of it, but in Angola, it’s all laid out in one place."

“Before this, there was not a place known to go and see the rocks on the surface that really reflected the opening of the South Atlantic Ocean, because they’re now in the ocean or eroded away,” he added.

Here's what the rocks from Angola tell about the breaking of the continent

Nearly 140 million years ago, Africa and South America started breaking off which caused gashes on the crust of the Earth and led to the opening up of the rifts along the pre-existing weaknesses. 

The tectonic plates beneath Africa and South America moved apart which led to magma from the mantle of Earth rising to the surface and forming a new oceanic crust while pushing the continents in opposite directions.

The gap between the two newly-formed continents was eventually filled with the South Atlantic Ocean.

“It’s one thing for a geophysicist to be able to look at seismic data and make inferences from that. It’s quite another thing to be able to take a school field trip out to the rock formations, or outcrops, and say this is when the lava was spreading from eastern South America. Or this was when it was a continuous land," said study co-author Michael J. Polcyn.