HR: 12:05h
AN: V22C-08    [Abstracts]
TI: Simulations of the Explosive Venting of Supercritical Fluids through Porous Media
AU: * Gisler, G R
EM: galen.gisler@fys.uio.no
AF: Physics of Geological Processes, University of Oslo PO Box 1048 Blindern, Oslo, 0316, Norway
AU: Svensen, H
EM: henrik.svensen@matnat.uio.no
AF: Physics of Geological Processes, University of Oslo PO Box 1048 Blindern, Oslo, 0316, Norway
AU: Mazzini, A
EM: adriano.mazzini@fys.uio.no
AF: Physics of Geological Processes, University of Oslo PO Box 1048 Blindern, Oslo, 0316, Norway
AU: Polteau, S
EM: stephane.polteau@fys.uio.no
AF: Physics of Geological Processes, University of Oslo PO Box 1048 Blindern, Oslo, 0316, Norway
AU: Planke, S
EM: planke@vbpr.no
AF: Volcanic Basin Petroleum Research, Oslo Innovation Park, Oslo, 0349, Norway
AB: Superheated or overpressured water and other fluids at depth can cause surface disturbances in the form of vents, seafloor pockmarks, or mud volcanoes. In sedimentary basins, magmatic intrusive events are a source of heating of included fluids. Metamorphic reactions triggered by heating can release more volatiles. Confined by impermeable clays or metamorphic rocks, the fluid is thus heated and pressurized. If confinement is breached in such a way that the superheated or overpressured fluid has access to porous sediments, a violent eruption of a mixture of fluid and sediment may result. Manifestations of this include both hydrothermal vents (as in the Karoo Basin of South Africa and the North Sea off the Norwegian coast) and mud volcanoes. Because these are widespread on Earth, they are likely to exist on other terrestrial planets where water or other volatiles are present. The search for such features is therefore relevant as a diagnosis for water, and hence life, on other planets. We have performed simulations with the Sage hydrocode (from Los Alamos and Science Applications International) of supercritical venting in a variety of geometries and configurations relevant to both Earth and Mars. The simulations show several different patterns of propagation and fracturing in porous or otherwise weakened overburden, dependent on depth, source conditions (fluid availability, temperature, and pressure), and manner of confinement breach. Because of the lower surface gravity and atmospheric pressure on Mars, such features should produce greater surface disturbances in the form of larger vent craters and more extensive aureoles than on Earth.
DE: 0545 Modeling (4255)
DE: 8020 Mechanics, theory, and modeling
DE: 8424 Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8135)
DE: 8426 Mud volcanism
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting