Search results
Results from the WOW.Com Content Network
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 ...
Approximate location of Mesoproterozoic (older than 1.3 Ga) cratons in South America and Africa. The São Luís and Luís Alves cratonic fragments are shown. Gondwana and the Kuungan orogen. Listed by modern continent and Gondwana, include:
Nevertheless, the oldest cratons on Earth include the Kaapvaal Craton, the Western Gneiss terrane of the Yilgarn Craton (~2.9 – >3.2 Ga), the Pilbara Craton (~3.4 Ga), and portions of the Canadian Shield (~2.4 – >3.6 Ga). Parts of Dharwar Craton in India are greater than 3.0 Ga. The oldest dated rocks of the Baltic Shield are 3.5 Ga old. [10]
The degree of certainty to which the identified landmasses can be regarded as independent entities reduces as geologists look further back in time. The list includes cratons, supercratons, microcontinents, continents and supercontinents. For the Archean to Paleoproterozoic cores of most of the continents see also list of shields and cratons.
Cratons are the oldest and most stable parts of the continental lithosphere, and shields are exposed parts of them. Terranes are fragments of crustal material formed on one tectonic plate and accreted to crust lying on another plate, which may or may not have originated as independent microplates: a terrane may not contain the full thickness of ...
Geological map of north-western Canada. Slave Craton is marked with A. Palaeomap of North American and Scandinavian cratons, basement rocks, and orogenic belts (ages in billions of years) The Slave Craton is an Archaean craton in the north-western Canadian Shield , in Northwest Territories and Nunavut .
Some of the Yilgarn regolith is the oldest in the world, recording weathering events as early as the Cretaceous Period. This has been created by the generally subtropical latitudes and conditions of the Yilgarn craton, with minimal to no glaciation and generally flat topographical relief resulting in comparatively minor erosion.
The craton is a composite of several different terranes of Archaean metasediments. The Dodoman is the oldest, and others include the Nyanzian and Kavirondian. Some of the greenstone belts are more than 3 billion years old. They were intruded by granites and migmatized in different events that date back to 2.9, 2.7, 2.4 and 1.85 billion years ...