Cratons

Source: Wikipedia. Pages: 60. Chapters: Canadian Shield, Guiana Shield, Superior craton, Pilbara craton, Trans-Hudson orogeny, Baltic Shield, Yilgarn Craton, Kaapvaal craton, Peridotite, Kalahari craton, Wyoming craton, West African craton, Arabian-Nubian Shield, Nain province, Laurentia, Zimbabwe craton, Gawler craton, Churchill craton, Saharan Metacraton, East European craton, North China craton, List of shields and cratons, Slave craton, Basement, Sao Francisco craton, Río de la Plata craton, Australian Shield, Dharwar craton, Rae craton, Sarmatian craton, Congo craton, Platform, Amazonian shield, Bangweulu Block, Sebakwe craton, Spavinaw terrane, East Antarctic craton, Indian Shield, Western Ethiopian Shield, Sclavia craton, Platform cover. Excerpt: The Superior craton (or Superior Province) forms the core of the Canadian Shield at the heart of the North American continent. It extends from Quebec in the east to eastern Manitoba in the west. The western margin extends from northern Minnesota through eastern Manitoba to northwestern Ontario. The formation of the Superior craton is best explained within the context of 2.72-2.68 Ga accretion of small continental plates and trapped oceanic terranes in a tectonic regime resembling that of today's rapidly changing southwestern Pacific Ocean. The craton is made up of a collage of small continental fragments of Mesoarchean age and Neoarchean oceanic plates and tracts of oceanic crust that consists of the following domains: Northern Superior, North Caribou, Winnipeg River, Marmion, Minnesota River Valley, Opatica, and Goudalie. These domains are generally separated by greenstone-granite terranes with long strike lengths that record various geodynamic environments, including oceanic floor, plateau, island arc and back-arc settings. Examples include the Oxford-Stull terrane in the north, the western Wabigoon in the west, and the Wawa-Abitibi subprovince in the southeastern Superior Province. A suite of Neoarchean monzodiorite intrusions from greenstone belts of the western Superior province have been termed "sanukitoid" because of their similarity in bulk chemical composition to high-magnesium andesite from Japan known as "sanukite." Neoarchean volcano-plutonic rocks of arc affinity dominate the oceanic margins of the Superior craton and indicate that there was widespread subduction prior to the 2.72-2.68 Ga collisional events that amalgamated the present-day Superior craton. However, during the amalgamation-collisions, five discrete orogenies are recognized. In the western and southern Superior province, the orogenies resulting from these collisional events all have the following common elements: 1) widespread calc-alkaline arc magmatism on the upper plate preceding colli