First Mystery
Previously, scientists used seismic waves to gather information about the earth’s composition. They discovered an interruption somewhere between three to six kilometers below the surface and believed that a transition in rock type was the cause, i.e. from granite to basalt.
However, the team found no change in rock type. Instead, they discovered granite rock continued to the core but went through some kind of metamorphic change. It was the first of many puzzling discoveries to follow.