Discoveries

May 02, 2023

The Big Slowdown

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A recent study is shedding new light on the formation of the Andes Mountains, while underscoring the complexity of geological processes, Science Alert reported.

The Andes range runs 5,530 miles down the western side of South America, with heights of up to 4.3 miles and a width of up to 435 miles at its widest point.

For their paper, a research team investigated how the movement of tectonic plates helped create the majestic mountain range, using a new method to examine the motion of the plates and providing insight into the speed of their movement over shorter time frames. They used a combination of absolute plate movement (APM) and relative plate movement (RPM) data.

APM shows how the plates move in relation to fixed points on Earth, while RPM shows how the plates move relative to each other. By using high-resolution RPM data to estimate APM, the researchers were able to calculate the rate of movement of the South American plate with more precision.

Researchers noticed that the South American plate – which formed the Andes – experienced significant slowdowns in its movement both around 10-14 million years ago and 5-9 million years ago. These slowdowns caused the Andes mountains to widen rather than grow taller, as the plate was compressed and pushed against the existing mountain range.

But the jury is still out as to what caused the slowdowns of the South American plate.

The team suggested changes in the convection currents in the Earth’s mantle or a phenomenon called delamination, where parts of a plate sink lower into the mantle.

However, more research and data are needed to confirm these explanations.

This story originally appeared in the May 02, 2023 newsletter, Hearts and Minds.