EUGENE M. MCCARTHY, PHD
The Afar Depression (also called the Danakil Depression or the Afar Triangle) is a geological depression formed by the junction of the East African Rift with the two spreading ridges that have formed the Red Sea and the Gulf of Aden. It lies near the Horn of Africa, overlapping Eritrea, Djibouti, and the Afar Region of Ethiopia.
In the depression, along each of the three rifts, the Earth’s crust is spreading apart at an annual rate of about 0.3-0.8 inches (1-2 centimeters). There are many deep fissures in the ground and small earthquakes occur in this region on an almost continuous basis. It’s one of two places on Earth where a spreading ridge, such as those normally found in the middle of the world’s oceans, can be studied on land (the other being Iceland).
The Afar contains the Middle Awash Valley, a region that has yielded many fossil hominid discoveries (in particular, Ardipithecus ramidus, Ardipithecus kadabba, and Australopithecus garhi); the Kada Gona river valley, site of discovery of the oldest stone tools known, which date to about 2.5 mya (Semaw et al. 1997, Semaw 2000); and Hadar, where Lucy, the best-known specimen of Australopithecus afarensis was found.
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