2012 Nanodiamonds and wildfire provide no support for meteorite impact at the end of the last Ice Age
Nanodiamonds and charcoal in Dutch soil provide no evidence for the alleged impact of a meteorite at the end of the last Ice Age. This is the conclusion of a research done by Utrecht University in collaboration with Leiden University and the University of Groningen.
No extraterrestrial cause for the sudden climate change
In 2007, American researchers supposedly found evidence of an extraterrestrial impact on top op the ice sheet in North America. They suggested that the impact caused the sudden climate change and, in its wake, the extinction of the mammoth.* According to the Americans, the impact also caused wildfires on a global scale, spread the rare element iridium and caused the alleged creation of several nanodiamonds.
"Charcoal and nanodiamonds are found in younger layers, long after the proposed impact. Our analysis therefore provides no support for an extraterrestrial cause for the sudden climate change", said Annelies van Hoesel (Utrecht University).
Charcoal in Usselo layer is a result of a forest fire
The transition to the Younger Dryas is marked clearly in a Dutch subsoil layer called the Usselo layer. Within this Usselo layer, changes in vegetation and layers of charcoal are clearly evident. The U.S. survey linked these findings to the alleged extraterrestrial impact.
For the study in Geldrop, the Usselo layer was accurately dated and soil samples were examined with electron microscopy. The study showed that the layer of charcoal is probably the result of a natural forest fire. Furthermore, the layer is hundreds of years younger than the alleged impact. The nanodiamonds also appear to be younger and probably have a different origin.
Temporary cold period after the Ice Age
After the last Ice Age, global warming was suddenly interrupted when glacial conditions returned. This temporary cold period after the end of the ice age, called Younger Dryas, lasted from 12,900 to 11,700 years before present. The cold was probably caused by the sudden deflation of a huge lake of icewater to the Atlantic Ocean. This stopped the ocean circulation that transports hot water from the equator to the north. The fires that took place in The Netherlands around this time can be explained without extraterrestrial impact.
You can read the full article by Annelies van Hoesel et al., as it is published in the 'Proceedings of the National Academy of Science (PNAS)', here: Nanodiamonds and wildfire evidence in the Usselo horizon postdate the Allerod-Younger Dryas boundary.
For more information contact Hans van der Plicht.
* Not only the alleged meteorite, but the research itself has launched a vigorous scientific debate. The researchers associated the impact with the disappearance of the prehistoric Clovis culture, seen as the first culture in the New World, together with the extinction of the mammoth. These assumptions are fiercely debated at conferences, in the media, the journal Nature and the internet. The story headlines in December 2007 in BBC World News with "Great beasts peppered from space".