The new observations hint that this part of East Africa may be closer to splitting \u2014 and doing so more rapidly \u2014 than previously thought. Researchers shared their discovery April 23 in Nature Communications<\/em>.<\/p>\n The Turkana Rift Zone straddles the countries of Kenya and Ethiopia on Africa\u2019s eastern edge. The region is best known for its wealth of fossils of our human ancestors<\/a>. But rocks beneath this rift zone hold their own secrets.<\/p>\n Christian Rowan studies Earth science at Columbia University in New York City. He and his teammates looked at past data on the Turkana Rift Zone. They included sound-based measurements that had been taken to search for oil and gas. Sending sound waves into the planet and watching how they bounce around can create images of what\u2019s below, Rowan explains. \u201cIt\u2019s almost like an ultrasound<\/a> of the upper crust.\u201d<\/p>\n The team focused on a layer of metamorphic rocks beneath the planet\u2019s surface. Those old, hard rocks form the crust under Earth\u2019s continents. Rowan\u2019s group traced those crustal rocks down to Earth\u2019s mantle. They found one region where the crust was just under 13 kilometers (8 miles) thick.<\/p>\n That was a big surprise, Rowan says. The crust is usually about 30 kilometers thick. (That\u2019s almost 19 miles.)<\/p>\n![\"a](\"https:\/\/www.snexplores.org\/wp-content\/uploads\/sites\/3\/2023\/07\/1440_SS_tectonic_plate.jpg\")
<\/a>The point of no return<\/h2>\n