Doors open at 5:30pm, program begins at 6:30pm.
In 1973, a young Jim Aronson, of Case Western Reserve University (CWRU), was invited to be the geochronologist for an exploratory project at Hadar, a site in the Afar Triangle of Ethiopia. Dr. Aronson, who had recently developed a system for dating minerals, joined project leaders Dr. Maurice Taieb, of France, and Dr. Donald Johanson, of CWRU and the Cleveland Museum of Natural History.
In this talk, Dr. Aronson will take you on a virtual field trip to the two most famous fossil localities at Hadar: AL 288, where Dr. Johanson would discover the iconic fossil “Lucy” in 1974; and AL 333, where the remains of at least 13 hominins (a group known as the “First Family”) were recovered in 1975 and 1976. Dr. Aronson will discuss how he used comparative sedimentology to reconstruct the ways in which Hadar’s paleo-environment differed from today’s very hot and dry Afar Triangle. Not only did he date the rock layers as spanning 3.4–3.0 million years ago, but he also found strong sedimentary evidence for a wetter, more diverse paleo-ecosystem in the Afar. This environment ultimately gave rise to our species—Homo sapiens.
Dr. Aronson will bring one very special rock hand specimen from his first Hadar season (1974) that reveals just how Lucy died 3.18 million years ago. Determining how the "First Family" died is a challenge because this group of fossilized bones was in a much more advanced stage of erosion than Lucy. The bones were mixed up and scattered widely over a steep slope; only a few were preserved in their original context. Dr. Aronson will share what those bones and their enclosing sediments can tell us about how this remarkable group of hominins, members of Lucy's species, lived and died about 3.22 million years ago—about 40,000 years earlier than Lucy.