Igneous rocks are usually found near volcanoes, like in the Pacific Northwest. But a team of University of Wyoming researchers found a two thousand-mile-long chain of the rocks much further inland.
Jay Chapman, UW assistant professor in geology and geophysics, said the belt of rocks is not continuous. The rocks are very unique, so his team was able to find them across western North America (through Idaho, Montana, Nevada, southeast California and Arizona) and link them together.
Chapman said these igneous rocks were created as the Earth's crust melted. Without nearby volcanoes, the temperature required for melting would have to be very high, but water might have helped.
"When we add salt to ice, it lowers the melting temperature and gets our ice to melt. Adding water to rocks is kind of like adding salt to ice, so adding water to rocks helps the rocks to melt," he said. "One possibility is maybe there was water introduced into the crust somehow that could have caused this melting to occur."
To test if that's what happened, UW researcher Jessie Shields is using computer simulations.
"You can get the geochemistry of the rock, you can put it into a computer program, and you can then see how the rock will melt at different pressures and temperatures and water content," she said. "You can use that to see whether or not it's possible to generate a lot of melt without water."
Shields said understanding the process that formed these rocks will help scientists understand the Earth's crust—where we all live.
Have a question about this story? Please contact the reporter, Ashley Piccone, at apiccone@uwyo.edu.
