May 14, 2026

In 2020, researchers installed one of 1,800 temporary magnetotelluric stations in Grant County, New Mexico, to test the electrical conductivity of rocks deep below the surface. Credit: Sarah Watson / Green Geophysics

Map of the US Deep Sea Reveals Ancient Continental Divide Beneath the Appalachians

A magnetotelluric array deployed for nearly two decades has revealed an exceptionally resistant rock body, known as the Piedmont Resistor, which may be a remnant of the breakup of Pangaea.