Pinnacle Point Site 5-6 has a very long and deep archaeological sequence both physically and chronologically. The excavation sequence is approximately 12 meters long and deep at the moment, dating at the top to 48,000 years ago and at the bottom to 90,000 years ago. How do we determine this? For each layer of sediment that is covered up, we can take a sample from it and determine the last time that sediment was exposed to sunlight. Sediments are dated using a technique called OSL (optically stimulated luminescence). When doing OSL dating, you are dating the last time a sand grain was exposed to sunlight—imagine windblown sand getting deposited in a cave and subsequently buried.
The archaeological sequence at PP5-6 contains several shifts in parent material making up the different sediments. We have divided the main bulks of similar sediment into stratigraphic aggregates, meaning sediment with similar parent material that are stratigraphically connected and bunched together into stratigraphical aggregates. At the bottom of our stratigraphic sequence, we have what we call the LBSR (short for Light Brown Sandy Roofspall). The main geological parent material for the LBSR is roof spall (or sediment that has fallen from within the cave wall or roof) and windblown (aeolian) sand. Delineating the vast quantities of sandy roof spall are lenses (or thin layers) of combustion features such as hearths, created by human occupation and contain artifacts discarded by humans.
Cobus, a local South African crewmember, is currently excavating in the LBSR dating from 76,000 years ago to 90,000 years ago. He is finding stone tools mainly made from quartzite (a coarse-grained raw material), shell fish, and fossilized bones. The shell fish is mainly brown mussel (Perna Perna) and is found in large quantities in what are probably hearths. The quartzite stone tools can look crude to an untrained eye, but the rough, serrated edge and solidness of these tools can make for very effective butchering tools, hide scrapers, wood working tools, and other uses. Fossilized bones from animals ranging in size from small tortoises and rock hyraxes to big antelopes such as elands and African buffalo have been recovered from these combustion features.
We had a special encounter close at the site on Friday. Some of the students found a snake that had eaten something very big for its size. It looked literally like a stuffed snake—kind of like me after I have eaten too much steak and lamb chops at a Friday night braai (South African for BBQ). Turns out, the snake is a puff adder—a very dangerous snake with one of the fastest strikes and most deadly poisons among all snakes. It is responsible for more snakebite deaths than any other snake in Africa. Luckily for us, the snake that we found was in no shape to cause any trouble whatsoever.
Med vennelig hilsen (Norwegian for “best wishes”)!