Changes

High temperature fields are found in areas of higher igneous activity. They are related to extremely high gradients, corresponding to global tectonic process. They occur in plate borders, cortical thin areas or hot spots. They need an igneous source, an aquifer, and a impermeable layer to keep up pressure. In many cases, there is surface evidence such as geysers and fumaroles.  

High temperature fields are found in areas of higher igneous activity. They are related to extremely high gradients, corresponding to global tectonic process. They occur in plate borders, cortical thin areas or hot spots. They need an igneous source, an aquifer, and a impermeable layer to keep up pressure. In many cases, there is surface evidence such as geysers and fumaroles.  

[[File: Simplified diagram of a geotermal power plant.png|frame|center|Simplified diagram of a geothermal power plant.<ref>[http://www.bgs.ac.uk/research/energy/geothermal/ British Geological Survey]</ref>]]

[[File: Simplified diagram of a geotermal power plant.png|frame|center|{{figure number|5}}Simplified diagram of a geothermal power plant.<ref>[http://www.bgs.ac.uk/research/energy/geothermal/ British Geological Survey]</ref>]]

===Hot dry rock deposits or geothermal stimulated systems ===

===Hot dry rock deposits or geothermal stimulated systems ===