Subduction Zone
Veteran Member
Since @Neb did finally answer my question about Lucy, and demonstrated a lack of understanding of the concept of scientific evidence in doing so, I do feel duty bound to answer one of his questions.
The basis for dating Lucy relies on radiometric dating. Though we cannot date the layer that she was in directly the formation that she was found in has occasional volcanic flows and ashes in it. Those can be dated directly with the 40Ar/39Ar method of radiometric dating. Those events give a bracket for the age of Lucy telling us that she was at least older than those deposits above her and younger than those below her. That along with other studies, such as paleomagnetic, sedimentology, and paleontology gives us a very accurate date of roughly 3.18 million years old:
Lucy's Story | Institute of Human Origins
The basis for dating Lucy relies on radiometric dating. Though we cannot date the layer that she was in directly the formation that she was found in has occasional volcanic flows and ashes in it. Those can be dated directly with the 40Ar/39Ar method of radiometric dating. Those events give a bracket for the age of Lucy telling us that she was at least older than those deposits above her and younger than those below her. That along with other studies, such as paleomagnetic, sedimentology, and paleontology gives us a very accurate date of roughly 3.18 million years old:
Lucy's Story | Institute of Human Origins