You might have heard something about a blob and Africa recently in the news. But what is a blob and how is it connected to Africa?
A blob is defined as a thick liquid or viscous substance. There are two enormous blobs deep under the earth’s surface and they are located on two opposite ends of the world. One of them is under the Pacific Ocean while the other one is beneath Africa. These blobs have been baffling scientists since their discovery in the 1980s. Each blob is the size of a continent and about 100 times taller than Mount Everest.
The blob under Africa is the one that’s catching the attention of scientists because it is slowly creeping up towards the Earth’s surface. That’s according to new research published by Nature Geoscience.
The two giant structures sit in the lowermost mantle, between around 400 and 1600 miles below the earth’s surface. These blobs are known as Low-Shear-Velocity Provinces or LLSVPs. Scientists believe the structures are incredibly dense and mostly made up of recycled oceanic crust or iron-rich material.
According to researchers, the two blobs differ in terms of their density. The African blob is far less dense which makes it more unstable than the Pacific one. It also sits 620 miles higher than the Pacific LLSVP, which makes it closer to the Earth’s surface. The African LLSVP is also much larger, with a maximum height of 990 to 1100 miles while the Pacific one is 430 to 500 miles high.
So what consequence do these massive blobs have?
For one thing, LLSVPs have been linked to volcanic activity. A study published in 2020 found the African blob led to intense volcanic activity in southeastern Africa between 155 and 95 million years ago. And as the structure rises, it elevates surface topography. A research published in 2010 in the journal Nature found that in the past 320 million years, 80% of massive eruptions of mantle rock that bring diamonds to the surface have taken place right over the boundary of the African blob.
If you’re thinking this massive eruption could happen in your lifetime, rest assured it will not happen even in your great grand kids lifetime. Scientists have not calculated the speed at which the blob is rising, but they believe it would still take a few million years to reach the surface if it keeps moving up. There is also the possibility of it sinking back down again once it moves up higher and becomes cold and even more dense.
There is still a ton of research left to be done on this matter and many, many questions to answer, like what caused these blobs to form in the first place.