For today’s theme I have resisted the temptation to post a photo of myself, and instead am going to show you the oldest thing I’ve ever photographed.
A 280 million year old tree. Several of them, in fact.
During August we spent a couple of weeks driving around Namibia in a minivan. We’d stay in one place for couple of days, see everything we could, then leave and drive for hours to get to the next place. Usually we stopped on the way to look at something and break up the journey.
On our way from Twyfelfontein to Etosha National Park, we came across signs for the ‘Petrified Forest’. We both vaguely remembered reading about this, so opened the guide book to see if it was worth stopping for. We were amused when the guide book warned that there were half a dozen ‘fake’ petrified forests, as well as the official National Monument forest.
It wasn’t hard to find the genuine Petrified Forest. It had an official signpost; all the others were obviously home written. Quite badly in some cases. The official site had buildings, toilets, a souvenir shop and sold cold drinks. We needed them by the end of the visit. It was scorching!
The Petrified Forest isn’t really a forest as such and the trees have not simply ‘turned into stone’.
These huge trees were probably snapped off at ground level and carried away from where they were growing in a violent Post Ice Age flood about 260 million years ago. They are very early conifers, so descendants of our firs and pines.
Once the trees came to rest, they were buried under layers of sand and rubble, where they did not decompose as they would have if they had been lying in the open air. Instead the many layers of sediment above the trees created such immense pressure that the quartz sediment surrounding the wood actually dissolved. The silica liquid then seeped into the wood, dissolving the organic materials and replacing them with silicic acid. This fossilised the wood by transforming it into stone. Millions of years later, wind and water erosion brought the now petrified trees to the surface again.
You can see the rings in this tree trunk.
A guide took us around the site, which was pretty large, 300 by 800 metres. It is illegal to take even the smallest bit of petrified wood from the site, but I can imagine people do try as there are pieces lying every where.
There is no doubt at all we were looking at trees, not just lumps of stone. You can see the wood rings, the bark and the knots where the branches once were.
The kids were initially interested in the concept, but quickly tired of looking at ‘very dead trees’. There was an aspect of ‘seen one, seen them all’, but it was amazing to think that we were standing beside things that were hundreds of millions of years old. To be honest, I struggled to get my head around the time scales involved myself, so was quite releved when it was time to retreat to the van and its air conditioning.
For more old things, check out this weeks Gallery at Sticky Fingers.