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1 Calculating Dome Thickness as a Function of Radial Distance for Cryovolcanic Domes on Europa ALYSSA MILLS 2 Cryovolcanism Definition: volcanoes that erupt volatiles instead of u molten rock Cryovolcanism creates domes through: u u
ALYSSA MILLS
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Definition: volcanoes that erupt volatiles instead of molten rock
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Cryovolcanism creates domes through:
u Diapirism u Extrusion of viscous fluid
Top figure: Diapirism and cryomagmatism schematic, taken from Fagents et al., 2003 Bottom left figure: Examples of cryovolcanic domes formed via diapirism or cryomagmatism, taken from Quick et al., 2017
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Understand the mechanisms of cryovolcanism
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Find if analogous with siliceous volcanism on Earth
u Run models made for siliceous
volcanism to cryovolcanism
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Gauge the activity on Europa
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Understand the role of tidal heating on Europa
Lava dome on Earth taken from USGS
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Created the method to measure the emplacement and relaxation of cryolava domes
u Tests multiple rheological
parameters, times, and radial distances
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Relaxation time of domes: 3.6 days to 7.5 years
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Models are consistent with the 2 sets of domes with radius of 3 km
Dome thickness as a function of radial distance using four time steps taken from Quick et al., 2016
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Location: Southern region near Libya Linea
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Cryovolcanoes formed from effusive processes
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Radius for Dome 1: 2 km
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Height for Dome 1: 25 m
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Radius for Dome 2: 1.9 km
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Height for Dome 2: 32 m
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Set up model to run six time steps based on:
u ℎ 𝑠, ⍬ =
'( )*+,
(.01 2 ⁄ )5/7 1 − +- +,
(.01 2 ⁄ )5/7 ./)
u Ends at final dome radius determined
from cross-sections
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Run model with different boundary conditions
u E.g. Time-dependent viscosity
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A.) t=12 hours
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B.) t=12 hours
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C.) None
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D.) t=3 days
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Overall closest match occurs at:
u t= 12 hours u Viscosity: 10; <-
=
u Results in final radius of 2001 m
and thickness of 23 m
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A.) t = 12 hours
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B.) t= 1.5 days
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C.) None
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D.) t=3 days
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Overall closest match occurs at:
u t= 1.5 days u Viscosity: 10; <-
=
u Results in final radius of 2001 m
and thickness of 33 m
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Consistent with Quick et al.’s results where smaller domes have shorter relaxation times
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These domes are smaller due to recent emplacement
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Expected to grow with time u
Use these smaller domes for more accurate initial dome radii and thicknesses for model
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Short relaxation time implies current active cryovolcanism
u Consistent with Roth et al., 2014’s prediction
Artist depiction of cryovolcanism on Europa, taken from NASA/JPL/Ted Stryk; NASA/JPL/Caltech
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Calculate dome relaxation with asymmetry
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Consider other aqueous solutions for better accuracy
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Apply models to other icy bodies with cryovolcanism
u E.g. Pluto
Close-up of suspected cryovolcanoes on Pluto’s southern terrain, taken from NASA