The Earth's mantle makes up about 85% of the Earth's volume and is made of solid rock. But exactly what rock types is the mantle made of, and how are they distributed throughout the mantle? An international team of researchers—including UT researcher Dr. Juan Carlos Afonso (Faculty of ITC)—have been able to reveal the existence of pockets of rocks with abnormal properties that suggest that they were once created at the surface, transported to vast depths along subduction zones, and accumulated at specific depths inside the Earth's mantle.