By Dr Romala Govender
If nothing else, COVID-19 has made us look at the world differently. This extends to our approach to our work around fossils too. Remote sensing has in recent times come to the fore as a new way to approach fossil hunting, bearing in mind this could reduce our time hunting and increase our time excavating. But, because COVID-19 restrictions meant that we were not able to continue with prolonged excavations at the West Coast Fossil Park (WCFP), WCFP, we needed to think outside the box to not only move excavations forward but to move our research programme forward as well. Hence, we turned to new technology. ‘E’ Quarry, within the WCFP, is a world-famous late Miocene to early Pliocene fossil site (Figure 1). It has produced a plethora of fauna and flora that has allowed for the reconstruction of the palaeoenvironment (Figure 2). It was also home to a bear, five species of hyena, a giant wolverine, honey badger, giant otter, a four-tusk elephant, and a short neck long horn giraffid and a variety of birds to name a few. Several the animals that lived there still have relatives living in the area today.
In 2009, I embarked on project that focused on the marine mammal fauna from the site. Cetaceans identified from the Cape’s West Coast provide biogeographic links to the Mediterranean, Atlantic of Europe, and North America, eastern North and South Pacific and the North Sea. An analysis of the seal fossils suggested that there were maybe two or three seal taxa living off the coast five million years ago. The fossil remains of the cetaceans are fragmentary and mostly consist of ear bones. In some cases, this makes understanding their relationships to other cetaceans from that time a bit difficult. The seals exist mostly as isolated specimens that number in the thousands. The inability to link skulls with postcranial again resulted in the lack of clarity of the identification of the different seals and their relationships.
To improve this situation, new excavations at the West Coast Fossil Park (WCFP) began in 2016. We limited excavations to two sites in ‘E’ Quarry that we thought could produce the best results based on previous results. Progress is slow as we work our way through the disturbed surface hoping to discover a bonebed like that on display (Figure 3). This disturbed material consists in some cases of areas where earth was moved as heavy machinery moved through and possibly due to some back filling.
What is ground penetrating radar (GPR)?
This is a geophysical technique that uses an electromagnetic wave (EM) sent out from a ground penetrating radar (GPR) that responds to the any changes in the subsurface properties (Stucchi et al. 2020). This non-destructive method assesses subsurface conditions but is not a “real-time” application because the data needs cleaning before interpretation (Leach 2021). The electromagnetic wave generated by the antenna then propagates in the subsurface; it can be reflected by an interface or scatters on an object (Stucchi et al. 2020). It has been used successfully in locating archaeological sites.
This is the first time this method will be deployed at ‘E’ Quarry.
In November 2022, the opportunity presented itself to carry out GPR scanning at the West Coast Fossil Park. This was done by Henk Steyn, Xander Fourie (PGS Heritage) and myself (Figure 5).
After discussions at the site, we identified two areas to scan. One was behind the current excavation moving towards the edge of the site (Site 4; Figure 6) and the other was the quarry floor where we have not investigated yet (Figure 7). A grid was set up at Site 4 and nine transects were scanned. On the quarry floor we took a different approach. We have not identified an area of interest, so we scanned a larger area not following a grid but rather doing transects across a wider area. We are currently analysing the results. We hope this exercise will identify new areas to excavate as well as help us improve our techniques to access fossil in future.