Posted on Saturday 20 November 2004

We're not just talking about pre-Clovis anymore, the latest news is that the first migration into the Americas may have even been pre-European and by that I mean really, really early.

The notion that the first people migrated to the Americas from Siberia via a land-bridge across the Bering Strait about 14,000 years ago continues to be the orthodox view in paleontological circles. These days, however, most scientists are open to the possibility that earlier migrations might have been occurred and evidence has been mounting for arrival dates ranging from 18,000-30,000 years ago.

But very few, I suspect, would have been expecting the latest results coming out of the Topper site at Allendale county in South Carolina. The team there working under Dr. Albert Goodyear has for several years been collecting evidence of artifacts in soil strata between 15,000 and 16,000 years of age. But in their latest dig they have uncovered a layer which has been radiocarbon dated to between 50,300 and 51,700 years old.

If true, this finding will upset more than a few apple carts because this date puts human migration to the Americas as early as the earliest human migration anywhere, period. Modern humans are thought to have arisen in Africa between 60,000 and 80,000 years ago before swiftly migrating to Asia by boat and on foot and arriving at Australia and Central Asia about 50,000 years ago. The first settlement of Europe is thought to have been only about 40,000 years ago.

To think that modern humans might have been walking around in America long before the last ice age is really quite amazing. We can only wait to see whether these dates can be independently confirmed. It's worth noting here that radiocarbon analysis does have some significant issues when attempting to date things of this age.

Anything that is less than about 50 or 60 000 years can be radiocarbon dated. Beyond 60 000 years there is hardly any radiocarbon left in a sample that is original. Often, in very old material, there is contamination which can significantly affect the accuracy of a date. Dating material from the archaeological or geological record beyond 30 000 years can be very difficult indeed unless the depositional situation of the sample is favourable and scientists can remove any contamination. Even a small amount of c14 from a contaminant can produce an incorrect date in an old sample. Often, radiocarbon daters release dates as being 'greater than 50 000 years' or 'greater than 45 000 years' because of the difficulty in reliably giving a date at this age.

An older article which has some background on the work being done at the Topper site can be found here.

^{Thanks, Peter.}