page_title: Heat-pipe tectonics
section_title: Theory
hierarchical_section_title: Heat-pipe tectonics / Theory
caption_attribution_description: English: Volcanic resurfacing. Upward advection of melts along vent form layers of volcanic materials at the surface. Downward advection of volcanic layers occurs under the stresses exerted on top and the void created when melts left. In addition, intrusions, e.g. diapir and sill, would occur at the base of the lithosphere.
context_page_description: Heat-pipe tectonics is a cooling mode of terrestrial planets in which the main heat transport mechanism in the planet is volcanism through the outer hard shell, also called the lithosphere. Heat-pipe tectonics initiates when volcanism becomes the dominant surface heat transfer process. Melted rocks and other more volatile planetary materials are transferred from the mantle to surface via localised vents. Melts cool down and solidify forming layers of cool volcanic materials. Newly erupted materials deposit on top of and bury older layers. The accumulation of volcanic layers on the shell and the corresponding evacuation of materials at depth cause the downward transfer of superficial materials such that the shell materials continuously descend toward the planet's interior.
  Heat-pipe tectonics was first introduced based on the observations on Io, one of the moons of Jupiter. Io is a rocky body that is internally extremely hot; its heat is produced by tidal flexing associated with its eccentric orbit. It releases internal heat via frequent and extensive volcanic eruptions that transfer melts to the surface.
context_section_description: In heat-pipe tectonics, volcanism is the major heat transport mechanism in which melts of rock are transferred to the surface by localised vents. Advection, referring to the transfer of mass and heat, occurs when a moving fluid carries substances or heat to or away from a source and through a surrounding solid along channels. Melts are produced when mantle rocks bear temperatures between 1100 and 2400 °C at corresponding depths (pressure varies the melting temperature) with the presence of water. When melts reach surface via vertical vents, they cool down and solidify forming mafic or ultramafic rocks which are rich in iron and magnesium. A thicker lithosphere is formed when volcanic materials accumulate on the Earth’s surface via repetitive volcanic eruptions. The new materials at the top, with the corresponding void created in the planet interior, lead to the sinking of superficial deposits. 
  This vertical advection of volcanic materials causes compression of the lithosphere, because interior spherical shells of planets are progressively becoming smaller at increasing depths.  The surface cools down and a cold, dense and strong lithosphere is developed. The thick lithosphere supports the mountains that result from the contraction of volcanic layers.
  Cooling heat-pipe planets could enter the next stage of cooling history, either lid tectonics or plate tectonics, immediately from the heat-pipe stage after prolonged cooling.
caption: Figure 1: Volcanic Resurfacing. Melts rise through vent reaching the surface and forms layers of volcanic materials constantly. As such, the newly deposited materials bury the older layers, pushing the older layers downwards. Besides, intrusions, e.g. diapir or sill, may occur at the bottom of the lithosphere.
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