The consensus was that global erosion of mountains and the Earth’s surface had been accelerating over the last 5 million years. Well, guess what? This once long accepted hypothesis has just been smashed by researchers at the GeoForschungsZentrum in Potsdam Germany. They present their results in the May 13 issue of Nature. GFZ Potsdam (click English top right). They write:
The globally observed four-fold acceleration of sedimentation is an artifact of the observations. Important geological hypotheses that are based on this observation now require revision.
Artifact of observation? Gee, where can one see that today? Hansen, are you reading?
Erosion of rocks and the Earth’s surface over the last 5 million years could be found as sediment. Measurements of the sediment layers suggested that erosion had increased over the last 5 million years. The question was why? What caused the acceleration?
Hypotheses for the cause included the increased global growth of mountains by movement of tectonic plates which resulted in accelerated erosion, or the onset of the ice ages 3 million years ago – which accelerated erosion. But neither of these hypotheses was satisfactory. Another wrench in the the machine was CO2 – it just didn’t pan out.
GFZ-scientists Jane Willenbring and Friedhelm von Blanckenburg appear to have solved the riddle.
They found that the increase in sedimentation rates is a so-called “artifact” of the observations: the more detail geologists observe, the more sediment they discover. In younger geologic time the observations get better than those made on sediment millions of years in age. This is so because not all sediment, once deposited, survives the passage of geologic time. The increase in sedimentation therefore is not real – it merely mirrors the better preservation of younger sediment.
Read the GFZ Potsdam report to see how they used isotope Beryllium-10 to solve the riddle.
Of course other scientists could claim that the consensus supports the old view, and that the GFZ researchers are just a couple of fringe scientists that can’t be taken seriously.