Sunday, 19 July 2015
Old art travels fast
They have known about other limestone caves in other parts of the world for many years but there was a feeling that the hot wet tropics would make a the preservation of such art very difficult; and therefore Indonesian rock art most be much more recent. Well not so. A team from U Wollongong in Australia have done some nifty science to date the earliest and latest possible dates for some wonderful pictures [and some less bonzer hand-prints] of mammals, including a probable babirusa, that were present on Sulawesi close to 40,000 years ago.
The technique hinged on the relentless accretion of calcium carbonate nodules (called cave pop-corn by the in-crowd), stalactites, stalagmites as the limestone is dissolved in the running water and recrystalised elsewhere. In places the art-work has been varnished by datable calcium warts. By cutting out a microcore of rock above and below the paint and analysing the relative contents of uranium vs thorium in each layer, the Wollongong team and their Indonesian collaborators have been able to date the art in one series of caves. That fact that it appears to be as old, but not older, than the art-work of Southern Europe is remarkable. There is no earlier art known from Africa or Australia - despite aborigines having been in Oz for 50Kyr. The proposal that this sort of carry-on should have evolved independently at the same time at opposite ends of the range of modern humans is too unlikely to contemplate. So we are left to conclude that itinerant artists were on the move, scoping out the local minerals, plying their trade, impressing the locals, training apprentices and painting, painting always painting. This reminds me of one of Primo Levi's great stories in The Periodic Table; Lead is about an itinerant leadsmith who walks his life away in search of new seams of heavy rock.
Movie time from Nature! Beyond the paywall (free for college people with proper infrastructure): Nature News&Views.