The neighborhood you grew up in never quite looks the same when you go back. The ancestral neighborhood of all humanity in East Africa went through some changes too as plate tectonics pulled the Earth's crust apart and created the Rift Valley.
The geological shift around the old homestead may have started sooner than originally thought.
"We now believe that the western portion of the rift formed about 25 million years ago, and is approximately as old as the eastern part, instead of much younger as other studies have maintained," said Michael Gottfried, a Michigan State University geologist, in a press release.
Gottfreid participated in a study that suggested the Rift Valley's two edges formed at around the same time, whereas earlier the eastern side was thought to be 15 to 25 million years older than the western side. Sediments from an ancient lake provided evidence that both halves formed about 25 million years ago.
"A key piece of evidence in this study is the discovery of approximately 25 million-year-old lake and river deposits in the Rukwa Rift that preserve abundant volcanic ash and vertebrate fossils," said study leader Eric Roberts of Australia's James Cook University in a press release.