The study in its context

Since its discovery, the age of Little Foot has changed several times. In the beginning, Ron Clarke and Tim Partridge, his colleague at the University of the Witwatersrand, relied on the morphology of the fossil and a paleo-magnetic dating of stalagmite flows to deduct an age of 3.3 million years. In 2003, a team from Purdue University in the United States dated the sediments surrounding the fossil through an analysis of its cosmogenic nuclides. This very new method gave an age of 4 million years. These estimations were quickly questioned, however, by another American laboratory that used the uranium-lead method to determine the age of the calcite floors surrounding Little Foot, giving a much younger age of between 1.5 and 2.2 million years.

In 2007, Ron Clarke and his team enlisted a French researcher, Laurent Bruxelles of Inrap, to help them solve the problem of dating Little Foot. A specialist of limestone landscapes and the caves carved into them, Laurent Bruxelles spent several years studying the context in order to understand the history of the landscape formation, make a map of the cave and clarify the succession of the sedimentary layers in which Little Foot was contained. This work required great sagacity in the face of these intersecting, overlapping and intermingling sediments. 

Once the complete stratigraphy of the cave had been decoded, it was possible to affirm two things. First, Little Foot was buried in the deepest, and thus oldest, layers of the cave. Second, the 2.2 million year-old stalagmitic flows previously used to date Little Foot are in fact much younger than the fossil since they were formed long after, within empty spaces under the skeleton. The researchers can now determine which sediments to date in order to attribute a definitive age to Little Foot.