Nature last week published an appreciation by Bernard Wood of the life and contributions of the late Frank Brown, who died earlier this fall: “Frank Brown (1943-2017)”. The first paragraph gives a good summary of the importance of Brown’s work:
Although not a palaeoanthropologist, Frank Brown played a major part in unveiling the story of human evolution. He devoted half a century to working out the complex geology of the fossil-rich sediments of East Africa’s Omo–Turkana Basin, one of the key sources of information about early human evolution. By matching up the chemical signatures of volcanic ash layers identified at sites across the basin, Brown provided a reliable way to place fossil and archeological finds in chronological order, adding immeasurably to what we know about human origins.
Brown and his students and collaborators contributed the intellectual basis on which we now understand the Rift Valley chronology of human origins.