Barrell was a teacher of mining engineering at Yale University, who developed (in 1917) a chronology for the Phanerozoic, based on rates of sedimentation and radiometric dating. He proposed that the anomalously low age of the Earth based on sedimentation rates could be explained by long gaps in the sedimentary record, called diastems, and that sediments formed only when subsidence occurred. Barrell was the first person to use the terms lithosphere and asthenosphere, based on his observations of isostasy.