The following post isn’t as much anthropology as it is geology, but that doesn’t mean it is warrantless and irrelevant to anthropology. On the contrary, geology has many tangents to anthropology. Often, physical anthropologists and archaeologists are in close collaboration with geologists, whom they recruit for their expertise in geochronology and context that many fossils and artifacts come from.
That being said, Geological Society of America is running a publication titled, “Blue Nile incision on the Ethiopian Plateau: Pulsed plateau growth, Pliocene uplift, and hominin evolution,” which addresses the how one of the Ethiopian Plateaus formed and how it aided in developing the great African grasslands and the Great Rift Valley (where many if not most hominin fossils have been found). As you may know, Darwin first suggested that a change of climate, gave rise to vast, arid, savannahs, which facilitated human evolution and potentially selected for bipedalism. But for sometime we’ve been wondering what caused that change of climate; what were the geological processes that led to the formation of the plateau?
Lead author Nahid Gani of the University of Utah and colleagues, answered these questions by integrating radar topography data and field observations. Their results indicate that rapid uplift of the plateau began about six million years ago and was related to the development of large shield volcanoes that erupted great volumes of basalt. These findings suggest that plateau formation resulted from the presence of a hot plume of mantle pushing up against the base of the African continent. The timing of plateau formation coincides with and is therefore probably related to the change in climate that gave rise to the African savannahs and ultimately to human evolution.