Fossil Tree Take

30 Aug 2020

At ... published in Science Advances  - see ... or ... researchers from the Smithsonian Tropical Research Institute found a large fossil tree buried in an grassy plain, in what looks like a fossil stream bed. It was high in the Andes of southern Peru. They also collected many smaples of fossil wood, leazves, and pollen grains which show these plants lived during a humid phase of climate. It is quite unlike the present high altitude dry climate of the region. This is assumed to be due to uplift of the Andes. The dates are interesting. Between 10 and 5 million years ago = mid to late Miocene and early Pliocene. Could this fossil tree be a relic of the Miocene/Pliocene boundary event?

... The tree is said to be perimineralised - petrified. It is unclear if the uplift occurred in its entirety at this time. Or did it occur in stages - and this was one of them. What is clear is that the ancestry of the tree is tropical forest. At 5 million years ago the pollen grains show mainly grasses and herbs growing, rather than trees. Climate change is invoked but this might have been a requirement for publication, or was inserted to assist publication.

. Note ... perimineralisation is thought to be a slow process. It involves an injection of mineralised water in order to preserve something like a tree trunk or tree branch. I have several pieces of wood turned into stone picked up from a Jurassic period sand quarry. However, there is nothing to say that it did not happen more quickly as the sand quarry, as an example, clearly involved some kind of storm, situated at the time in an estuarine location. Perimineralisation could occur contemporary with a catastrophic event. One that involved water. This could be a great storm, a tsunami wave, or any of a number of things. It doesn't have to be world shaking. On the other hand, if a catastrophic event coincided with the Miocene/Pliocene boundary and then indeed it may well be extensive in scope.

At ... climate change is said to have also affected the Neanderthals. Between 100,000 and 40,000 years ago. A particularly severe cold phase of climate is dated at around 60,000 years ago, the Weichel glacial. Neanderthals appear to have adapted to a more mobile lifes style. The theory revolves around a study of Neanderthal stone tools. Interesting study.