craton

"There are ancient platforms (cratons) at Agsu pass," he said.

However, researchers encountered a mystery while conducting these studies - the seismic waves appear to gain speed while passing through super-old rock formations dubbed cratons.

But these diamonds are unreachable: They're located about 90 to 150 miles (145 to 240 kilometers) below the surface of the Earth in the "roots" of cratons, which are large sections of rock.

The North China Craton (NCC), located between the Central Asian Orogenic Belt (CAOB) to the north and the Central China Orogen (CCO) to the south, is one of the oldest and largest cratons in the East Asia (Figure 1(a), [35, 36]).

Le pensionnaire du Sporting Lisbonne, en instance de transfert vers un club anglais, est sous le coup d'une suspension automatique pour cumul de cratons. C'est ce qui explique finalement l'effectif grandement amoindri qui s'est deplace hier a la capitale seychelloise a bord d'un vol special de la compagnie Air Algerie.

Abundance of feldspar indicates that the sandstones are immature and likely were transported from nearby cratons. The adjacent Indian shield or the east Antarctic shield could be the possible sources.

"The reason why the Gamburtsevs are so enigmatic is that stable cratons are generally low-lying features with no huge mountain ranges atop," Fausto Ferraccioli, a geophysicist at the British Antarctic Survey in Cambridge, England said.

Meteoric's geophysical consultants advise that the magnetic character of these anomalies is consistent in shape, size and amplitude with those associated with some kimberlite and lamproite pipes in Archean cratons and Proterozoic mobile belts.

Kober could not know that today, 90 years later, cratons would be objects of intense study.

Ennih (El Jadida U., Morocco) and Liegeois (Royal Museum for Central Africa, Belgium) present 25 papers resulting from the UNESCO International Geological Correlation Program 485 on "Cratons, metacratons and mobile belts; keys from the West African craton boundaries: Eburnian versus Pan-African signature, magmatic, tectonic, and metallogenic implications." The program brought together African, European, And American geologists to conduct research on the boundaries of the West African craton (the old and stable part of the continental crust).

Numerous questions remain, but these less familiar, non-uniformitarian processes explain in part why Archean cratons do not look like modern continental plates, even though many of the second-order processes were similar (e.g., Vlaar, 1986; Zegers and van Keken, 2001; Bleeker, 2002; Hamilton, 2003).