Tom Higham has helped out paleoanthropologist Erik Trinkaus and his team redate the fossil remains of Neandertals from the G1 level of the Vindija cave site in Croatia. In 1998-99, excavations in the Vindija caves yielded fossil Neandertals as well as cave bear bones, lead by a team who included Trinkaus; the Neandertal fossils were previously dated, by radiocarbon analysis to be 28,000 to 29,000 years old.

The efforts of Tom Higham et al. and “improvements, particularly in sample pretreatment techniques for bone radiocarbon samples, especially ultrafiltration of collagen samples” have shifted the age of the fossil remains 3,000 years more, to a date because, as the older paper indicated, a “possible problem with contamination by more recent carbon in the specimens, which would make the dates younger than they ought to be,” as John Hawks phrases it. John Hawks also quotes an “illuminating” paragraph from the paper:

“This situation currently makes it difficult to use an archaeological complex, such as the Aurignacian, as a correlate for the spread of modern humans across Europe during this biocultural evolutionary transitional time period (in contrast to Mellars 2005). Several factors play into this ambiguity. It is possible that the dating difficulties described above with reference to Vindija may be more widespread than hitherto anticipated, and that the 4,000-year gap between the earliest directly dated modern humans and the earliest Aurignacian is a function of radiocarbon acccuracy on the few dated specimens…”

The quote is significant because it questions the age of all dated Aurignacian specimens.

You can read more about this find here, here, and here.