Technology
Mysterious and unstable ‘blobs’ the size of continents beneath Earth’s surface baffle scientists
FOR years scientists have been scratching their heads over two unexplained massive blobs of rock under Earth’s surface.
Many theories have been thrown around since their discovery in the 1980s, including claims that they could be huge fragments of an alien world.
Mingming Li/ASU3D model of the blobs beneath[/caption]
The blobs of rock under Earth’s crust are each the size of a continent and 100 times taller than Mount Everest.
One sits under Africa, while the other can be found under the Pacific Ocean.
In pursuit of answers, a pair of experts have made some interesting new discoveries about the two gigantic masses.
As suspected, it turns out, the blob under Africa is a lot higher.
In fact, it’s twice the height of the one on the opposite side of the world, measuring in about 620 miles taller.
And that’s not all.
Crucially, scientists have found that the African blob of rock is also less dense and less stable.
It’s not clear why things are this way but it could be a reason for the continent having significantly more supervolcano eruptions over hundreds of millions of years, compared to its counterpart on the other side.
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“This instability can have a lot of implications for the surface tectonics, and also earthquakes and supervolcanic eruptions,” said Qian Yuan, from Arizona State University.
These thermo-chemical materials – officially known as as large low-shear-velocity provinces (LLSVPs) – were studied by looking at data from seismic waves and running hundreds of simulations.
While we now know they both have different compositions, we’re yet to work out how this affects the surrounding mantle, which is found between the planet’s core and the crust.
And most importantly, we’re no closer to figuring out where these mysterious blobs came from.
“Our combination of the analysis of seismic results and the geodynamic modeling provides new insights on the nature of the Earth’s largest structures in the deep interior and their interaction with the surrounding mantle,” Yuan added.
“This work has far-reaching implications for scientists trying to understand the present-day status and the evolution of the deep mantle structure, and the nature of mantle convection.”
And so, the investigation continues.
The research was published in the Nature Geoscience journal.
A timeline of life on Earth
Here’s a brief history of life on our planet
4.6billion years ago – the origin of Earth
3.8billion years ago – first life appears on Earth
2.1billion years ago – lifeforms made up of multiple cells evolve
1.5billion years ago – eukaryotes, which are cells that contain a nucleus inside of their membranes, emerge
550million years ago – first arthropods evolve
530million years ago – first fish appear
470million years ago – first land plants appear
380million years ago – forests emerge on Earth
370million years ago – first amphibians emerge from the water onto land
320million years ago – earliest reptiles evolve
230million years ago – dinosaurs evolve
200million years ago – mammals appear
150million years ago – earliest birds evolve
130million years ago – first flowering plants
100million years ago – earliest bees
55million years ago – hares and rabbits appear
30million years ago – first cats evolve
20million years ago – great apes evolve
7million years ago –first human ancestors appear
2million years ago – Homo erectus appears
300,000 years ago – Homo sapiens evolves
50,000 years ago – Eurasia and Oceania colonised
40,000 years ago – Neandethal extinction
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