- Hydrothermal circulation
Hydrothermal circulation in its most general sense is the circulation of hot water; 'hydros' in the Greek meaning water and 'thermos' meaning heat. Hydrothermal circulation occurs most often in the vicinity of sources of heat within the Earth's
crust. This generally occurs near volcanicactivity, but can occur in the deep crust related to the intrusion of granite, or as the result of orogenyor metamorphism.
eafloor hydrothermal circulation
Hydrothermal circulation in the
oceans is the passage of the water through mid-oceanic ridgesystems.
The term includes both the circulation of the well known, high temperature vent waters near the ridge crests, and the much lower temperature, diffuse flow of water through sediments and buried
basalts further from the ridge crests. The former circulation type is sometimes termed "active", and the latter "passive". In both cases the principle is the same: cold dense seawater sinks into the basalt of the seafloor and is heated at depth whereupon it rises back to the rock-ocean water interface due to its lesser density. The heat source for the active vents is the newly formed basalt, and, for the highest temperature vents, the underlying magmachamber. The heat source for the passive vents is the still-cooling older basalts. Heat flow studies of the seafloor suggest that basalts within the oceanic crust take millions of years to completely cool as they continue to support passive hydrothermal circulation systems. Hydrothermal vents are locations on the seafloor where hydrothermal fluids mix into the overlying ocean. Perhaps the best known vent forms are the chimneys referred to as black smokers.
Volcanic and magma related hydrothermal circulation
Hydrothermal circulation is not limited to ocean ridge environments. The source water for
geysers and hot springs is heated groundwaterconvecting below and lateral to the hot water vent. Hydrothermal circulating convection cells exist any place an anomalous source of heat, such as an intruding magmaor volcanicvent, comes into contact with the groundwater system.
Hydrothermal also refers to the transport and circulation of water within the deep crust, generally from areas of hot rocks to areas of cooler rocks. The causes for this convection can be:
* Intrusion of magma into the crust
* Radioactive heat generated by cooled masses of granite
* Heat from the mantle
* Hydraulic head from mountain ranges, for example, the
Great Artesian Basin
* Dewatering of metamorphic rocks which liberates water
* Dewatering of deeply buried sediments
Hydrothermal circulation, particularly in the deep crust, is a primary cause of
mineraldeposit formation and a cornerstone of most theories on ore genesis.
volcanogenic massive sulfide ore deposit
Wikimedia Foundation. 2010.
Look at other dictionaries:
Hydrothermal vent — Marine habitats White smokers emitting liquid carbon dioxide at the Champagne vent, Northwest Eifuku volcano, Marianas Trench Marine National Monument Littoral zone … Wikipedia
Thermohaline circulation — A summary of the path of the thermohaline circulation/ Great Ocean Conveyor. Blue paths represent deep water currents, while red paths represent surface currents The term thermohaline circulation (THC) refers to a part of the large scale ocean… … Wikipedia
Mont hydrothermal — Une cheminée hydrothermale dans l océan Atlantique Les monts hydrothermaux, cheminées hydrothermales, sources hydrothermales ou fumeurs, sont des évents hydrothermaux situés à proximité des dorsales océaniques. Ils sont une conséquence des… … Wikipédia en Français
Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… … Universalium
Cold seep — Marine habitats Tube worms are among the dominant species in one of four cold seep community types in the Gulf of Mexico. Littoral zone … Wikipedia
Deep sea — zones For the IMAX film, see Deep Sea 3D. The deep sea, or deep layer, is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms … Wikipedia
Oceanic zone — Marine habitats The oceanic zone is the deep open ocean water that lies off the continental slopes Littoral zone Intertidal zone … Wikipedia
Seabed — This article is about ocean floor. For the 2001 song by Audio Adrenaline, see Lift (Audio Adrenaline album). Map showing the underwater topography (bathymetry) of the ocean floor. Like land terrain, the ocean floor has ridges, valleys, plains and … Wikipedia
Ore genesis — The various theories of ore genesis explain how the various types of mineral deposits form within the Earth s crust. Ore genesis theories are very dependent on the mineral or commodity. Ore genesis theories generally involve three components:… … Wikipedia
Volcanogenic massive sulfide ore deposit — Volcanogentic massive sulfide ore deposit at Kidd Mine, Timmins, Ontario, Canada, formed 2.4 billion years ago on an ancient seafloor. Volcanogenic massive sulfide ore deposits (VMS ) are a type of metal sulfide ore deposit, mainly Cu Zn Pb which … Wikipedia