East out of Africa

The dispersal of humans out of, and into, Africa is one of the great mysteries of the remote past, especially into Southwest Asia and Arabia. Recent research in arid Southwest Asia has focused on ancient, long dried-up lakes, which were visited repeatedly by hominins of many forms. Such sites as have been located tend to yield but small samples of tools, until the recent investigation of Khall Amayshan 4, a series of superimposed lake sequences within a basin among dunes. A nearby paleolake basin at nearby Jubbash has added more detail of multiple human dispersals into Arabia over the past 400,000 years, clearly associated with climatic shifts.

The oldest occupation dates to about 412,000 years ago, associated with Acheulian hand axes (see image), the oldest dated in Arabia. There were later occupations in about 337,000 and 306,000 years ago, by which time stone technology was more advanced, with no more hand axes. The use of carefully prepared “Levallois” stone cores was now commonplace. The animal bones found in the occupation levels provide striking evidence for wetter conditions, with hippopotamus flourishing in what must have been fairly deep water.

There are now signs of five pulses of hominin dispersal into northern Arabia, each associated with wetter conditions. This is just the beginning of a long process of discovering and documenting the complex history of how various human species spread beyond Africa, a far more intricate process than the simple migration arrows of yesteryear.

Image: Handaxe from Khall Amayshan 4.