Tuesday, December 01, 2015

Core of North American continent is 'extremely deformed'

[Daily Mail] Researchers have found that the Earth's continents really aren't as solid as a rock.
A groundbreaking new study found that cratons, the cores of continents, are less stable than thought.
They discovered the craton beneath the North American continent is extremely deformed, and has moved 850 kilometres - but they don't know why, or when.
They says its root is shifted relative to the center of the craton by 850 kilometers towards the west-southwest. 
It was assumed that cratons are stable because of their especially solid structure due to relatively low temperatures compared to the surrounding mantle.
A team of German-American scientists now discovered that these cratons that were assumed to be 'as solid as a rock' are not that solid after all. 
The team lead by Dr. Mikhail Kaban from the GFZ German Research Centre for Geosciences now discovered that the craton beneath the North American continent is extremely deformed: its root is shifted relative to the center of the craton by 850 kilometers towards the west-southwest.
This fact is in contrast to the prevailing assumptions that these continental roots did not undergo substantial changes after their formation 2.5 to 3.8 billion years ago. 
The study that appears in the latest online publication of Nature Geoscience contradicts this traditional view. Read More