> ...a team of researchers has described the discovery of an obsidian handaxe workshop within a layer of sediment dated to 1.2 million years ago.<p>What kind of radiometric dating is used for sediment? Is it not possible for older sediment to shift around and cover newer stuff?
Axes this old are not unheard-of. They have been identified as up to 2 million years ago (Homo Erectus?). This paper is about the tool yard, and it's proximity to the source material. Or so I understand.