Climate Change and Human Evolution

The goal of the project is to test hypothesized linkages between climate and mammalian (including hominin) evolution in tropical-subtropical eastern Africa by the acquisition and analysis of long sediment core records of environmental change from the Chew Bahir basin. The time interval investigated by analysis of the cores is the last 620,000 yrs. This time interval includes the episodic presence of archaic Homo sapiens (<500 ka BP, including H. heidelbergensis andH. rhodesiensis), anatomically modern humans (AMH, since <200 ka BP), and H. sapiens sapiens (the subspecies including all modern humans, since ~100 ka BP). It also includes the first (apparently failed) dispersal of AMH from Africa (125-100 ka BP) and the successful "Out of Africa II (or III)" expansion at around 80-40 ka BP.

We collected long (~290 m) continuous drill core records of mostly lacustrine deposits spanning the full time interval of the evolution of our own species and its direct ancestors. All investigations of these cores are based on comprehensive experience in the analysis of short cores obtained in the same locality (see Chew Bahir Coring Project), provenance and remote sensing studies in the southern Ethiopian Rift, and precipitation statistics. This project contributes to the Hominin Sites and Paleolake Drilling Program led by A. Cohen (U Arizona).