How old is Art?

 

Michael - Thursday

Giraffe from Tsodilo

Stanley and I have always been fascinated by the San (Bushman) peoples. They appear in major or minor roles in several of our stories (including the new book that we're trying to finish right now). One of the most fascinating aspects of their culture is the wonderful rock art that they left behind all over southern Africa. Rock art is one of the earliest expressions of human imagination and culture and some of the works are superb by any measure. That they are worth preserving is beyond question. 

The rock engravings survive the ages and many go back almost 50,000 years. Unfortunately, most of the paintings are on the walls and ceilings of caves, which are exposed to the elements to a greater or lesser extent, and they will inevitably deteriorate over the years. There are many ongoing projects involving photographing and tracing the paintings designed to preserve as many as possible before they are gone forever.

If this is the beginning of art, it’s important to know just how old they are. When we look at the wonderful examples of San rock art at Tsodilo and many other places, we assume that we know a lot about them, including their age, give or take a few hundred years. However, age turns out to be really hard question and one that archaeologists and anthropologists are still working on to this day.

Eland from Tsodilo

The most powerful tool we have is carbon dating. It’s complex and clever, requiring sophisticated equipment to produce accurate results from tiny samples, but the basic principle is straightforward. You measure the decay of C14 – an isotope of carbon. In living organisms, carbon is replaced in the system all the time by absorbing food, which contains lots of carbon in various molecular forms.  So in a living creature the C14 ratio to the common C12 (the stable isotope) is pretty well fixed at the ambient levels. However, when the organism dies, the carbon is frozen, and the C14 content gradually decays to nitrogen. That means that the longer the organism is dead, the less C14 it contains as a proportion of carbon. Thus, based on that ratio one can estimate the age. C14 has a half-life of about 5,000 years, so if the amount of C14 in a fossil is half of the ambient proportion, then the fossil will be roughly 5,000 years old.

Rhino and a buffalo(?)

The problem is that the pigments used in rock art are generally inorganic materials which means that carbon dating is useless. This is where the scientists get clever. Some of the art in southern Botswana has been dated to between five and ten thousand years old by analysing chards of painting that have broken off the rock and measuring the carbon in the soot used as a base. Soot is a mixture of charcoal and fat – both good sources of carbon. The amounts are tiny, but that’s where the smart part comes in.

Kangaroo from the Kimberley in West Australia

 A group of Australian scientists have developed an intriguing method of attacking the problem of the age of Aboriginal rock art in the Kimberley region of north Western Australia. They noticed that many of the art works occur in caves where a certain type of wasp habitually built its mud nests. These nests are built to last – the mud is held together by a natural glue that the wasp secretes. And it really works. For tens of thousands of years! And the solid mud contains organic material albeit in tiny amounts.

Artwork with mud wasp nest remains

Taking the nests off the surface of the art works allowed the scientists to collect enough material to date the nests to up to 20,000 years old. But that’s only half the story. Since the nests were built after the art was painted, the paintings are at least that old but could be much older. However, the nests are so long-lived that they actually leave a residue that may become fossilized. Some of the paintings are painted over the fossilized residue. Dating the fossilized residue, gives an upper limit for the age of the art work. They found a very few paintings that had both the fossilised residues below the paintings and the residues on top of them. That enabled them to date the works to around 20,000 years old.

And that turns out to be the same order of age as the oldest art works at Tsodilo - the wonderful world heritage site in north-west Botswana, half the world away.

Geometric ochre rock painting found at Blombos Cave

It’s now believed that the oldest human art currently known is a geometric design painted on a shard of rock. Was the design decoration or did it have a deep spiritual meaning? We will probably never know. The shard was probably broken from a much larger work. It was found in the Blombos Cave site about halfway between Cape Town and Knysna about ten years ago and has only been dated comparatively recently. They were able to date it because unlike “modern” rock art, the fragment was buried in the cave floor along with a layer of artefacts some of which were made with organic materials. Since the layer was undisturbed at the time of the excavation, it was possible to assume that the rock shard was left there at roughly the same time as the other materials. It turns out that the other materials dated to around 73,000 years ago.

Rock engraving of the same age from Blombos Cave

Art has been important to humans for a very long time!