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Cratons of South America and Africa during the Triassic Period when the two continents were joined as part of the Pangea supercontinent. A craton (/ ˈ k r eɪ t ɒ n / KRAYT-on, / ˈ k r æ t ɒ n / KRAT-on, or / ˈ k r eɪ t ən / KRAY-tən; [1] [2] [3] from Ancient Greek: κράτος kratos "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two ...
A craton is an ancient part of the Earth's continental crust which has been more or less stable since Precambrian times. Cratons whose ancient rocks are widely exposed at the surface, often with relatively subdued relief, are known as shields.
This model is specifically proposed for how the Yang Tze Craton and the North China Craton collided and thinned the lithosphere. [32] The collision of the 2 cratons first thickened the crust by folding. [32] Eclogite formed in the lower crust, which made the lower crust denser. [32] New shear zones also developed in the lower crust. [32]
Laurentia basement rocks. Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America.Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and the Hebridean Terrane in northwest Scotland.
Smaller cratons of Precambrian rocks south of the Amazonian Shield are the Río de la Plata Craton and the São Francisco Craton, which lies to the east. The Río Apa Craton at the Paraguay-Brazil border is considered to be likely just the southern part of the Amazonian Craton. [2] The rocks of Río Apa were deformed during the Sunsás orogeny. [3]
Similar to Zhao et al.'s model, Santosh [41] split the Western Block into Yinshan Block and Ordos Block in the north and south respectively. However, instead of Khondalite Belt, he named the collision region of the two sub-blocks Inner Mongolia Suture Zone. Discontinuous Khondalite Belt exposures lie inside south of the Inner Mongolia Suture Zone.
Cheney 1996, nevertheless, found a three-fold stratigraphic similarity and proposed that the two cratons once formed a continent which he named Vaalbara. This model is supported by the palaeomagnetic data of Zegers, de Wit & White 1998. [4] Reconstructions of the palaeolatitudes of the two cratons at 2.78–2.77 Ga are ambiguous however.
The Kaapvaal Craton covers an area of approximately 1,200,000 km 2 (460,000 sq mi) and is joined to the Zimbabwe Craton to the north by the Limpopo Belt.To the south and west, the Kaapvaal Craton is flanked by Proterozoic orogens, and to the east by the Lebombo monocline that contains Jurassic igneous rocks associated with the break-up of Gondwana.