A fumarole is a word that originates from the Latin word ‘fumus’ meaning smoke. A fumarole is an opening in the planet’s crust that emits steam and gases like carbon dioxide, sulphur dioxide, hydrogen sulphide, and hydrogen chloride. The steam from the fumarole becomes superheated when the water boils and the pressure drops when it emerges from the ground. Solfatara is the name of the fumarole which emits sulphurous gases. Fumarole occurs along the tiny cracks, fissure or through the chaotic clusters or the fields.
Fumaroles occur on the surface of the lava or the pyroclastic flows. A fumarole field is the area of the thermal springs, here the gas vents where the shallow magma or the hot igneous rocks releases the gases or it interacts with the groundwater. The fumaroles occurring in the freezing condition may cause fumarolic ice towers.
Fumarole
A fumarole is a vent on the Earth’s surface. From this fumarole, the steam and the volcanic gases gush out. The main source of the water vapour which emits by the fumaroles is the groundwater which is being heated by the bodies of magma that lies relatively close to the surface. Carbon dioxide, Hydrogen Sulphide, Sulphur Dioxide usually is emitted directly from the magma. The Fumaroles are generally present on active volcanoes which occur during the period of relative quiet between the eruptions.
Fumaroles are closely related to the hot springs and geysers. In these areas the water table rises near the surface, the fumarole then becomes hot springs. A fumarole that is rich in sulphur is called a solfatara while a fumarole that is rich in carbon dioxide is called mofette.
Steam Cave and Vent Sites
Geographical features like fumaroles or steam vents are found on the Big Island of Hawaii Island. Steam caves and vent sites are the least studied thermal features, while these are the only terrestrial hydrothermal feature which is readily available for investigation on the Hawaii Island. Although they are considered to be a lack in the living microbes due to their temperatures. The steam that is filled in the caves and vents of Hawaii are found to contain a broad diversity of microorganisms. Steam is formed from the meteoric waters that descend into the subsurface and then they meet upward as convection of heat.
The steam then quickly forms, by rising vertically to the surface through the crevices and from the fissures in the lava. As this comes near the surface, it fills horizontally or vertically in the caves and it exits the passageway in a continuous or in the form of burst-like structure. This depends on the flow of the rate.
Although some of these caves have high burst discharge which is emitted out of it, the steam can be considered to be an artesian flow. Physically these steam caves can be either shallow, which can be 1 m or less, or this can be deeper to several meters, within the narrow or wide openings.
Hot Springs and Geysers
Hot Springs and Geysers are the manifestations of volcanic activity. They are the result of the interaction of the groundwater with the magma which then solidifies when it has hot igneous rocks at its shallow depths.
The Yellowstone National Park which is in the United States is one of the most famous areas of the hot springs and geysers in the world.
The total heat emitted out from these thermal features is estimated to be approximately 300 megawatts. The last great eruption which happened at the Yellowstone occurred around 630,000 years ago when some 1,000 cubic km of the rhyolitic pumice was ejected in huge pyroclastic flows and this resulted in the formation of the caldera.
Yellowstone lake occupies part of the giant caldera. This is the last great outburst which happened about 1,200 cubic km (288 cubic miles) of the rhyolite lava which flowed and formed domes that have erupted in numerous smaller events. The cooling roots are those which had past eruptions, or it has possibly been new intrusions of magma at the shallow depth. Here emit the heat sources for the Yellowstone hot springs and geysers.
Geysers are the hot springs that intermittently spout a column of hot water and steam into the air column. This action of the geyser is caused by the water in deep conduits which is beneath the geyser and they approach or reach the boiling point. At around 300 metres below the surface, the boiling point of water increases to around 230 °C (or 450 °F), for this there is an increase in the pressure of the overlying water. When the bubbles of steam or any dissolved gas begin to form, and they rise up, they expand, forming hot water spills from the geyser’s vent, this lowers the pressure on the water column below. The water at depth then momentarily exceeds its initial boiling point and then it flashes into steam, this forces additional water from the vent. This is a chain reaction that continues until the geyser exhausts off its supply of boiling water.