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Explore the boundary layer models of Martian hydrothermal systems by studying the impact of magma intrusion on groundwater heating. Utilizing scaling laws and numerical solutions, discover the heat and mass flow behavior in this unique environment. Understand the governing equations, conservation principles, and implications for gully formation on Mars.
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Boundary layer models of Martian hydrothermal systems Kate Craft 11/2/2007
Deep Sea Vents Photo taken by I.R. Jonasson, 1992 Photo Credit: Peter Etnover
Hydrothermal Systems on Mars Magma intrusion heats up surrounding groundwater Magma Chamber Impact Crater Gulick, 1998 Newsom, 1980
Martian gullies • Geomorphology • Gullies • Stepped fans • Outflow Channels • Oceans New gulley discovered in 2005 Gulick, 1998 NASA/JPL
Basic Model v y g u T = 4C V = 0 MAGMA Porous medium full of water Vertical, Impermeable, Heated Wall x Tw = 500C q = 0, impermeable • Assumptions • Single phase flow (water always in liquid phase) • Wall at constant temperature • Water source is existing groundwater
Governing Equations Conservation of Mass Conservation of Momentum Conservation of Energy Bejan, 1995 m =density of mixed rock/fluid and medium; f = density of fluid Can solve numerically, but also know general behavior through scaling law y x
Numerical Solutions Temperature and Velocity Profiles y 4km Integrate across to get heat and mass flow outputs 2km Boundary Layer • T reaches ~ T • v reaches ~ 0 0 x, m 100 200
Heat Output Results to 1δ • at heights of 1 and 10 km above the bottom of the magma chamber • captures more than 99% of the heat flux that occurs out to 3
Volume Flux to 1δ • at heights of 1 and 10 km above the bottom of the magma chamber • which captures greater than 95% of the volume flux that occurs out to 3
Comparison to Martian Hydrographs Drainage Networks Northern Ocean 107 Outflow channel 105 Ma’adim Vallis Stepped Fans Estimated volume water (km3) 103 Esberwalde Delta 102 Gullies Kraal, 2007 10 107 10 102 103 105 Estimated formation time range (years) • 100 km long dike with a depth of ~ 5 km injected into a highly permeable rock would transport ~10 km3/yr of fluid
Conclusions & Future Work • Permeability primarily controls the mass and heat flux • Total amount of heat and mass delivered depends upon the lifetime of the intrusion • For given assumptions output volume can create gullies on the order of years • Future work • Use FISHES program to consider: • Time dependence • Two phase saltwater flow • Brine formation • The high permeabilities • of Martian regolith
References Bejan, A., 1995, Convection Heat Transfer 2nd ed., 639 p., Wiley, New York. Gulick, Virginia. “Magmatic intrusions and a hydrothermal origin for fluvial valleys on Mars.” Journal of Geophysical Research, Vol. 103: E8, Aug. 1998. Newsom, H. E., 1980, Hydrothermal alteration of impact melt sheets with implications for Mars, Icarus, v. 44, p. 207-216. Correspondence with Dr. Erin Kraal, Geological Sciences Department, Virginia Tech University, Blacksburg, VA, 2007.