Across the United States, an array of 1,800 stations has been probing the electrical conductivity of rocks deep beneath the surface. This Magnetotelluric Array has uncovered hidden fragments of continent, the stretching of crust and places likely to harbor mineral deposits, Paul Voosen reports at Science. https://www.science.org/content/article/deep-earth-map-reveals-lost-u-s-continent #ScienceMastodon