An Ethiopian Journal

"Until lions have their historians, tales of the hunt shall always glorify the hunters"

Posts Tagged ‘East African Rift valley

The Cradle of Humanity

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“This region of Africa has both archaeological and anthropological significance. Hominid fossils found here indicate that this region may be the origin of humanity’s presence on Earth, and the Nile River valley and delta are the home of numerous archaeological sites from the time of the Pharaohs.

The East African Rift valley is an example of an active divergent rift valley, one of the few areas on Earth where a continent is being actively separated (rifted) by the ongoing forces of plate tectonics. The actual profile of the valley is a nearly exact match to the profile of the central axis of mid-ocean ridges. The East African Rift valley connects to the seafloor of the Red Sea. The central depths of the Red Sea are also the site of active tectonic movement, as the African Plate slowly separates from the Arabian Plate. At the bottom of the Red Sea, Earth’s inner heat creates hot pools of brine (extremely salty water) that give rise to exotic copper, zinc, manganese, and iron minerals.

North of the Rift Valley, in central Ethiopia, are the Simien Mountains and Lake Tana. Lake Tana is the source of the Blue Nile. Just a few miles south of the lake is Tississat, “Water That Smokes”,, also called Blue Nile Falls. The Simien Mountains feature the highest point in Ethiopia, Ras Dejen. Simien Mountains National Park is a UNESCO human heritage site.

Several specimens of early hominid fossils, particularly australopithecines, the likely ancestors of modern Homo sapiens, have been found here, as well as at Hadar and the Middle Awash River sites in the Afar Triangle. The famous “Lucy” skeleton, an example of Australopithecus afarensis, was found in the Hadar area. Early specimens of genus Homo, including Homo habilis and Homo erectus, were also found in the Omo River/Lake Turkana region.

Some anthropologists speculate that one reason the East Rift Valley was where human beings originated was the ongoing geological rifting process in the area. They believe that this process led to considerable ecological stress and disruption, a situation that favors rapid evolution and even the development of intelligence. The distribution of fossils in various parts of the Rift Valley makes this theory difficult to confirm, as the global climate was also undergoing fairly rapid climate change. The climate in this African region was clearly becoming cooler and drier, leading to changes in vegetation cover from forests to grasslands and expansion of deserts. One of the primary changes that may have occurred in the early hominids was the development of the ability to walk, perhaps due to the loss of forest cover and the expansion of grasslands

The delta of the Nile River is prominent on the coast of the Mediterranean Sea, above Cairo, Egypt. The fertility of the Nile Delta and the banks of the Nile River provided stable agriculture for the Egyptian civilization of the Pyramids and the Pharoahs. To the south of the broad green Nile River valley is the dark water of Lake Nasser, formed by the Aswan High Dam. The reduction of sediments in the Nile north of the river, due to trapping of the sediments in Lake Nasser behind the Aswan dam, is one reason that the Nile River delta is slowly sinking.”

Written by Tseday

September 1, 2008 at 11:32 pm