Ring of Fire Eruptions of basaltic to rhyolitic volcanoes and hypabyssal rocks of the Alert Bay Volcanic Belt in northern Vancouver Island are probably linked with the subducted margin flanked by the Explorer and Juan de Fuca Plates at the Cascadia subduction zone. It appears to have been active during the Pliocene and Pleistocene. However, no Holocene eruptions are known, and volcanic activity in the belt has likely ceased. The Kamchatka Peninsula in the Russian Far East is one of the most various and active volcanic areas in the world, with an area of 472,300 km. It lies between the Pacific Ocean to
Circum-Superior Belt margin. The last collision occurred on the southeastern portion of the Superior craton to produce the Grenville orogeny 1,100 million years ago. Because most of the Circum-Superior Belt was formed by widespread mafic-ultramafic magmatism 1,884 to 1,864 million years ago along the Superior craton margin during these orogenies, a number of different suggestions have been made to explain the questionable origins of this large igneous province. It is also not clear if the Circum-Superior Belt has a single origin or it has several origins. Suggestions include back-arc rifting, foredeep flexure, mantle plumes and the breakup of a microcontinent. The geochemical