#Hadar, Anthropological and archaeological site, Ethiopia

#Hadar, site of paleoanthropological excavations in the lower Awash River valley in the Afar region of Ethiopia. It lies along the northernmost part of Africa’s Eastern (Great) Rift Valley, about 185 miles (300 km) northeast of Addis Ababa. The lower valley of the Awash River—i.e., the Hadar area—was designated a #UNESCO World Heritage site in 1980.

The Hadar remains include partial skeletons of #Australopithecusafarensis, a key species in human evolution. Major #paleontological work began at Hadar in the early 1970s and was led by the #American anthropologist Donald Johanson. His team discovered a 40-percent-complete female skeleton of A. afarensis that became popularly known as #Lucy. Dated to 3.2 million years ago, the remains provided further evidence that, in human evolution, walking on two legs (bipedalism) preceded increased brain size. The pelvis and leg bones indicate upright posture, but the skull bones reveal a limited cranial capacity similar to that of modern #chimpanzees. The A. afarensis-bearing levels at Hadar range from 3.4 to 2.9 million years old and include more than 200 fossils from a single site (Afar Locality 333), representing at least nine adults and four juveniles deposited at the same time. Thorough analyses of the remains reveal a pattern consistent with a single, highly variable species, the males of which were significantly larger than the females, although there is the possibility that the sample instead consists of two different hominins (members of the human lineage). The site has also yielded the earliest known remains of the human genus, Homo, which date to 2.3 million years ago, along with some of the earliest known evidence of tool use.

“#Lucy”

“Lucy,” a 3.2-million-year-old Australopithecus afarensis skeleton found by anthropologist Donald Johanson in 1974 at Hadar, Ethiopia.

#ReplicaskullofLucy

Reconstructed replica of the skull of “Lucy,” a 3.2-million-year-old Australopithecus afarensis found by anthropologist Donald Johanson in 1974 at Hadar, Ethiopia.

? Bone Clones, www.boneclones.com

Located at the juncture of the Arabian, #Somali, and #Africantectonic plates, the Eastern #RiftValley has experienced significant geologic upheaval. Over several million years, numerous volcanic eruptions laid down layers of volcanic ash at Hadar, effectively covering fossil remains with a succession of strata that have been systematically identified and dated by researchers. Seismic activity combined with heavy erosion has gradually exposed the region’s fossil record, greatly reducing the amount of excavation required for locating hominin remains. These conditions make Hadar one of the world’s richest sources of information on the physiology and habitats of #homininspecies.

#Paleontology

"Lucy," one of the most famous hominin fossils, is a 3.2 million-year-old Australopithecus afarensis fossil discovered in Hadar, Ethiopia by Donald Johanson in 1974.

The first paleo-geological explorations of the Hadar area were conducted by Maurice Taieb. He found Hadar in December 1970 by following the Ledi River, which originates in the highlands north of Bati to empty into the Awash River. Taieb recovered a number of fossils in the area and led a party back to Hadar in May 1972. In October 1973, 16 individuals with the International Afar Research Expedition (IARE) arrived at Hadar and camped there for two months during which the first hominin fossil was found. (Taieb claims in his 1985 book Sur la Terre des premiers Hommes to have discovered the Hadar fields in 1968, but Kalb argues that claim of an earlier find to be incorrect.) The IARE party examined a series of sedimentary layers called the Hadar Formation, which was dated to the late Pliocene to early Pleistocene epochs (3.5 to 2.3 million years ago).

The anthropologist Donald Johanson, a member of the 1973 expedition to Hadar, returned the next year and discovered the fossil hominin "Lucy" in the late fall of 1974.[6] He spotted a right proximal ulna in a gully, followed by an occipital bone, a femur, some ribs, a pelvis, and a lower jaw. Within two weeks, nearly 40% of the hominoid skeleton had been identified and cataloged. Lucy is the most famous fossil to have been found at Hadar. Lucy is among the oldest hominin fossils ever discovered[6] and was later given the taxonomic classification Australopithecus afarensis. (The name 'Lucy' was inspired by the song "Lucy in the Sky with Diamonds" by The Beatles, which happened to be playing on the radio at base camp.)

In 1975, Donald Johanson made another discovery at a nearby site in Hadar: 216 specimens from approximately 17 individuals, most likely related and varying in age, called AL 333 (colloquially referred to as the "First Family").

About thirty years later in nearby Dikika, another Australopithecus afarensis fossil skeleton was found in a separate outcrop of the Hadar Formation across the Awash River from Hadar. The skeleton is of a three-year-old girl later named "Selam," which means peace in Amharic Ethiopian languages.

#HadarGeology

The region consists mainly of mudstones, stiltstones, fine-grained sandstones and volcanic tuffs. The region has been divided into 4 geologic members: Hadar Formation: Basal (～3.8–3.42 Ma), Sidi Hakoma (～3.42–3.26 Ma), Denen Dora (～3.26–3.2 Ma), and Kada Hadar (<～3.2 Ma) with the three tufts: Sidi Hakoma Tuff (SHT), the Triple Tuff (TT) and the Kada Hadar Tuff (KHT) separating the four members.

The Sidi Hakoma member tends towards high rainfall and low seasonality. The overlying Denan Dora Member was a grassland habitat. Finally, the Kada Hadar Member was an even more open and arid habitat as seen in the high abundance of antilopins, an animal that frequents these types of terrains.

Read more articles from: https://www.sciencedirect.com/science/article/pii/S1631068316301233

https://www.researchgate.net/figure/Location-and-drainage-map-of-the-Hadar-paleoanthropological-site-Solid-lines-indicate_fig1_259011653