Researchers create first detailed global map of flow within the Earth’s mantle, and they find out that the surface is moving up and down “like a yo-yo.”
Researchers at University of Cambridge, have compiled the first global set of observations of flow within the Earth’s mantle, the layer between the crust and the core and found that it is moving much faster than has been predicted.
Above: The crust, the thinnest layer of the Earth. Below is the mantle (red), the largest layer stretching from 400 to 1,800 miles below the surface, outer core (orange), and inner core (yellow-white). Credit Argonne National Laboratory
Dr Mark Hoggard of Cambridge’s Department of Earth Sciences, the paper’s lead author, said:
“Although we’re talking about timescales that seem incredibly long to you or me, in geological terms, the Earth’s surface bobs up and down like a yo-yo. Over a period of a million years, which is our standard unit of measurement, the movement of the mantle can cause the surface to move up and down by hundreds of meters.”
The team, from the University of Cambridge, used more than 2000 measurements taken from the world’s oceans in order to peer beneath the Earth’s crust and observe the chaotic nature of mantle flow, which forces the surface above it up and down. These movements have a huge influence on the way that the Earth looks today – the circulation causes the formation of mountains, volcanism and other seismic activity in locations that lie in the middle of tectonic plates, such as at Hawaii and in parts of the United States.
They found that the wave-like movements of the mantle are occurring at a rate that is an order of magnitude faster than had been previously predicted. The results, reported in the journal Nature Geoscience, have ramifications across many disciplines including the study of oceanic circulation and past climate change.
source University of Cambridge