"It pushes back the beginning of anatomically modern humans," says geologist Frank Brown, a co-author of the study and dean of the University of Utah's College of Mines and Earth Sciences.
The journal Nature is publishing the study in its Thursday Feb. 17, 2005, issue. Brown conducted the research with geologist and geochronologist Ian McDougall of Australian National University in Canberra, and anthropologist John Fleagle of New York state's Stony Brook University.
The researchers dated mineral crystals in volcanic ash layers above and below layers of river sediments that contain the early human bones. They conclude the fossils are much older than a 104,000-year-old volcanic layer and very close in age to a 196,000-year-old layer, says Brown.
"These are the oldest well-dated fossils of modern humans (Homo sapiens) currently known anywhere in the world," the scientists say in a summary of the study.
Significance of an Earlier Emergence of Homo sapiens
Brown says that pushing the emergence of Homo sapiens from about 160,000 years ago back to about 195,000 years ago "is significant because the cultural aspects of humanity in most cases appear much later in the record only 50,000 years ago which would mean 150,000 years of Homo sapiens without cultural stuff, such as evidence of eating fish, of harpoons, anything to do with music (flutes and that sort of thing), needles, even tools. This stuff all comes in very late, except for stone knife blades, which appeared between 50,000 and 200,000 years ago, de