Researchers studied the uplifted edges of continental crust along the Oman-United Arab Emirates border and made some interesting breakthroughs in understanding how these beautifully banded landmasses may have formed. 

Our world is made up of a series of plates that are constantly moving as they float on the hot, plastic-like mantle below. In some cases, the plates are rubbing edges, in others they’re moving apart, and sometimes they’re crashing together. This particular plate boundary is a subduction zone, where a lower density plate is crashing into a higher density plate and is getting forced under. 

Since different minerals form at different pressures and temperatures, it’s possible to look at the now tilted edges of these plates to see how different layers formed over time. According to a paper appearing in Tectonics with first author T.K. Ambrose, as the higher density plate dove under the lower density plate, its top layer adhered to the bottom of the lower density plate on top. 

Initially, this was a hot process with significant pressure, but over time, more and more rock was added at lower and lower temperatures but not higher pressures. This seems to indicate that things were cooling, but the pressure just never let up on this rock. Now we know that when we look at these banded uplifts, sometimes you’re seeing just one tectonic plate, and sometimes you’re looking at a plate that has scraped layers of another plate, like so many layers of wallpaper.

More Information

A Closer Look at the Creation of a Metamorphic Sole (Eos)

“Burial, Accretion, and Exhumation of the Metamorphic Sole of the Oman-UAE Ophiolite,” T. K. Ambrose et al., 2021 March 23, Tectonics