Volcanoes have indeed been clearly observed on other bodies in the solar system – on some, such as Mars, in the shape of mountains that are unmistakably old volcanoes (most notably Olympus Mons), but on Io actual ongoing eruptions have been observed.
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Movement of molten rock in the mantle, caused by thermal convection currents, coupled with gravitational effects of changes on the earth's surface (erosion, deposition, even asteroid impact and patterns of post-glacial rebound) drive plate tectonic motion and ultimately volcanism.
The Cayman Rise extends from southeastern Cuba along the northern margin of the Cayman Trough toward Costa Rica and resulted from Paleocene to Eocene island arc formation with associated volcanism along an extinct subduction zone.
Cretaceous volcanism in the offshore of Queensland was related to a minor episode of arc formation, typified by the Whitsunday Islands, followed by development of offshore coral platforms, passive margin basins and far-field volcanism throughout the quiet Hunter-Bowen orogenic belt.
The Creataceous volcanism did also created minor outcrops of potassic alkaline volcanics in a graben structure developed between Asunción and Villarrica and in Amambay Department.
In a recent rocks and sediment analysis or petrographic study on the lakes and adjoining rivers in San Pablo, sulfate concentrations were considerably higher than the naturally occurring sulfates from volcanism.
Tor Zawar is a group of closely spaced fissure vents on a non-volcanic mountain in a tectonically active region between the Bibai and Gogai thrust faults (Global Volcanism Program) which is in the Ziarat reigon near the village of Wham.
Other manifestations of the Yellowstone hotspot: Rexburg Volcanic Field (4.3 Ma), West of Rexburg, Idaho; Henry’s Lake Volcanism (1.3 Ma), Henry's Lake; Blackfoot Volcanic Field (3 Ma), Northwest of Soda Springs, Idaho; Gem Valley Volcanic Field (600 to 50 ka), near Grace, Idaho.