Sentences with word «craton»

We discovered these microfossils preserved in a layer of hard silica - rich rock called chert located within the Kaapvaal craton of South Africa.»

Inclusions found in the Museum's diamonds from the Congo craton in central southern Africa illustrate an incredible 3 - billion - year journey through tectonic collisions and volcanic eruptions.

Carol Finn, of the U.S. Geological Survey, a co-author on the paper, says, «Resolving the contradiction of the Gamburtsev high elevation and youthful Alpine topography but location on the East Antarctic craton by piecing together the billion year history of the region was exciting and challenging.

These cores that are called cratons are the oldest known geological features of our planet.

What caused the deformation of the stable and solid craton?

Deformed craton under North America.»

As a result of plate tectonics, Alaska is an amalgamation of terranes that have collided with the North American craton and have accreted to become part of North America.

Known as cratons, these masses have deep mantle roots that can reach down some 200 kilometers below the surface.

One ancient formation, the Zimbabwe craton, is of interest because «it looks like it was formed in a different way» from others, such as that in Australia (Pilbara) or South Africa (Kaapvaal).

3.48 billion year old siliceous rocks of the Dresser Formation, Pilbara craton, Western Australia, preserve evidence for having formed in hot springs on land — the earliest life on land yet known, and about the same age as when life may have been present on Mars (a wetter time in its past, with heating from once active volcanoes and bolide impacts).

«Re-melting or recycling of this primitive crustal ancestor produced the younger rocks of the Archean craton, which grew and stabilized to form the core of this part of the North American continent.»

-- Atlanta, GA -LRB--RRB--- Black nerds and geeks The paper presents data on high - grade silicate — carbonate rocks (calciphyres) from the Irkut block (Sharyzhalgai uplift, southwestern Siberian craton).

The name is a reference to the Tepui mesa Autana, a spectacular plateau and cave system along the Guiana Shield craton.

«This indicates that the craton is not as solid and as insensitive to the mantle flow as was previously assumed,» Kaban completes.

However, a team of scientists has now discovered that these cratons that were assumed to be «as solid as a rock» are not that solid after all.

It was assumed that the cratons are stable because of their especially solid structure due to relatively low temperatures compared to the surrounding mantle.

There is far more mechanical, chemical, and thermal interaction between the craton of billions of years in age and its surrounding in the upper mantle of Earth than previously thought.

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 leading by Dr. Mikhail Kaban from the GFZ German Research Centre for Geosciences now discovered that the craton below 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.

Cratons are pieces of continents that have been largely stable for hundreds of millions of years.

«Our findings suggest that the primordial crust involved in forming our craton was actually more than 4.2 billion years old and similar in composition to oceanic crust, which is very different from continental crust,» O'Neil said.

We knew that the craton in northern Quebec had been formed by partial fusion of an ancient precursor crust, but for the first time we have specific information about the age and the nature of this older source,» lead author Jonathan O'Neil from the University of Ottawa's Department of Earth and Environmental Sciences said in a statement.

Cratons are the oldest portions of Earth's continents that have remained stable for over a billion years.

This unified piece of ancient continental crust, called a craton, lies exposed at the surface in the Canadian Shield, and forms a solid foundation...