Hotspots

Source: Wikipedia. Pages: 36. Chapters: Hotspots of North America, Hotspots of the Atlantic Ocean, Hotspots of the Indian Ocean, Hotspots of the Pacific Ocean, Hotspots of the Southern Ocean, Hawaii hotspot, Great Lakes tectonic zone, Yellowstone hotspot, Anahim hotspot, Galápagos hotspot, Samoa hotspot, Iceland hotspot, Bermuda hotspot, New England hotspot, Louisville hotspot, Bowie hotspot, Raton hotspot, Réunion hotspot, Cobb hotspot, Erebus hotspot, Easter hotspot, Mackenzie hotspot, Tristan hotspot, Kerguelen hotspot, Canary hotspot, Ocean island basalt, Macdonald hotspot, Balleny hotspot, Trindade hotspot, Matachewan hotspot, Pitcairn hotspot, Juan Fernández hotspot, St. Helena hotspot, Azores hotspot, Eifel hotspot, Marquesas hotspot, Meteor hotspot, Jan Mayen hotspot. Excerpt: The Hawaii hotspot is the volcanic hotspot that created the Hawaiian Islands in the central Pacific Ocean, and is one of Earth's best-known and most heavily-studied hotspots. While most volcanic activity occurs along tectonic plate boundaries, powered by the plates' movement, hotspots can occur far from such geological boundaries, so that a different model, involving unusual features in the Earth's lithosphere, is required. Seafloor spreading pulls Hawaii's volcanoes northwest about 10 centimeters (3.9 in) a year, so that 30 million years ago, the Kure and Midway atolls were located where the island of Hawai'i is now. The oldest extant volcano in the chain, Meiji Seamount, began to form 86 million years ago; the hotspot may be older, however, since subduction of tectonic plates on the margin between the Pacific and Eurasian plates may have destroyed older volcanoes. The Hawaii hotspot has created the Hawaiian - Emperor seamount chain comprising at least 129 volcanoes arranged in a line with a sharp bend. More than 123 of these are extinct volcanoes, seamounts, and atolls, four are active volcanoes, and two are dormant volcanoes. Hawaiian volcanoes range in age from 300,000 to 86 million years, progressing from southeast to northwest. This chain includes the Hawaiian Ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor seamounts, a linear region of islands, seamounts, atolls, shallows, banks, and reefs along a line trending southeast to northwest beneath the southern Pacific Ocean. The chain stretches over 5,800 kilometers (3,604 mi) from the Aleutian Trench in the far northwest Pacific to Loihi Seamount, the youngest volcano in the chain, lying about 35 kilometers (22 mi) southeast of the Island of Hawai'i. A bend corresponding to rocks between 41 and 43 million years old, sharply divides the Hawaiian and Emperor sections. The bend is now thought to result from movement of the hotspot, superseding the theory of a relatively