Fumarole


A fumarole is an opening in a planet's crust which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrogen chloride, and hydrogen sulfide. The steam forms when superheated water boils as its pressure drops when it emerges from the ground. A fumarole that emits sulfurous gases can be referred to as a solfatara.
Fumaroles may occur along tiny cracks, along long fissure, or in chaotic clusters or fields. They also occur on the surface of lava or pyroclastic flows. A fumarole field is an area of thermal springs and gas vents where shallow magma or hot igneous rocks release gases or interact with groundwater. When they occur in freezing environments, fumaroles may cause fumarolic ice towers.
Fumaroles may persist for decades or centuries if located above a persistent heat source; or they may disappear within weeks to months if they occur atop a fresh volcanic deposit that quickly cools. The Valley of Ten Thousand Smokes, for example, was formed during the 1912 eruption of Novarupta in Alaska. Initially, thousands of fumaroles occurred in the cooling ash from the eruption, but over time most of them have become extinct.
An estimated four thousand fumaroles exist within the boundaries of Yellowstone National Park in the United States. In April 2006 fumarole emissions killed three ski-patrol workers east of Chair 3 at Mammoth Mountain Ski Area in California. The workers were overpowered by toxic fumes that had accumulated in a crevasse they had fallen into. Another example is an array of fumaroles in the Valley of Desolation in Morne Trois Pitons National Park in Dominica.
Fumaroles emitting sulfurous vapors form surface deposits of sulfur-rich minerals; places in which these deposits have been mined include:
The formation called Home Plate at Gusev Crater on Mars, which was examined by the Mars Exploration Rover Spirit, is suspected to be the eroded remains of an ancient and extinct fumarole.