U.W. 101-2076 Block synchrotron scan

Aim/rationale:

During a 2014 excavation in the Hill Antechamber of the Rising Star Cave system, a Homo naledi child’s skeleton was recovered mostly intact. The skeleton was recovered from a subsurface feature intact by encasing the body in a plaster jacket. This was done in order to preserve the articulated context and to preserve the interior sediments for potential future molecular studies such as aDNA and proteomics. This is an unprecedented situation as we have never had a case where an early hominid in such condition has been recovered intact in soft sediments, so the conservation and preservation of this encased individual is paramount and will certainly add significantly to future scientific studies.
In order to establish the contents of the feature, we CT scanned the block in a medical CT. This revealed the partial skeleton, including many articulated remains (Figure 1). In addition, the scans revealed a tool shaped rock near one of the hands of the child. Unfortunately, the medical scans did not give enough resolution to see for certain whether this is a tool or just a rock shaped like a tool. The Wits Micro CT scanner has been down for almost two years and now that it is running again, we have attempted to scan this block in order to get a higher resolution image of the rock. Unfortunately, the window of the microCT is simply too small to scan a block this large and we are not getting good enough images to see the morphology of the specimen. The establishing of whether this is in fact an artefact is of utmost scientific importance, however, we are at present unwilling to excavate into the block containing the infant as this will contaminate the specimen and destroy material and context that may be of some significant scientific value.
We would like to take the specimen to the ESRF, covid permitting, in February. It is our understanding that the ESRF has the capacity to scan a block of this size and this would obviously give us very high resolution images that would ensure we could establish whether this is a tool or not. A byproduct would be that we would also have scans of the infant skeleton, allowing intensive studies to be done of this individual.