A dormant Illinois volcano has rare earth metals. Scientists want to know why

Millions of years ago, there was a near volcanic eruption in southern Illinois.

“It did not actually erupt lava onto the surface,” said Southern Illinois University geologist Daniel Hummer. “The magma got really close to the surface. It sort of punched those topmost layers of rock upwards to form the dome.”

The now-dormant volcano is called Hicks Dome, and scientists like Hummer are fascinated by its geology, as it contains an unusual concentration of rare earth metals and radioactive minerals. Hummer hopes to better understand how it formed these materials.

“When you dig in and see what is under the surface on that hill, what you find are some very bizarre types of igneous rocks — igneous being the type of rock that forms from molten rock formed from magma,” Hummer said.

Hummer and his students have researched the site for several years. He specializes in crystal mineralization and regularly collaborates with other experts at the Illinois State Geological Survey for this work.