THE OCEANS OF EUROPA AND GANYMEDE. AQUEOUS SOLUTION UNDER PRESSURE AS POTENTIAL HABITATSO. Prieto-Ballesteros (1), V. Muñoz-Iglesias (1) and L. Jiménez Bonales (1, 2)(1) Centro de Astrobiología. INTA-CSIC, Madrid, Spain (2) Complutense University, Madrid, Spain
MOTIVATION There are some indirect evidences of the presence of liquid reservoirs in
the interior of Europa and Ganymede. There are no direct data about the characteristics of aqueous cryomagmas yet. Cryomagmatic processes have interest for Astrobiology because involve relative warm water rich liquids
Simulation experiments can provide some knowledge about the chemical reactions and geological processes that can be expected to occur at subsurface conditions
The information that we already have about the endogenic materials at the surface, the geochemical models of the satellite, and the geophysical models about the internal structure, are used for setting up the experiments
Experiments: Crystallization of gas clathrates from salty solutions Solubility of gases under pressure in salty solutions Processes of fractional crystallization of cryomagmasEvolution of aqueous liquids
Environmental constraints for habitability
CONSTRAINTSEUROPA Pressure. We consider a total
pressure range from 1 to 1800 bar, taking into account a water ice crust of 20km (≈240 bar) and a total water-rich layer of 100-150 km (cryomagmas ascend into the crust)
Temperature , dependent on the solution composition
Composition. We assume the aqueous composition is mainly sulfate rich, with CO2 (sulfuric acid and other salts are also considered)
EQUIPMENT Two different high pressure chambers located at Centro de
Astrobiología (CAB-INTA-CSIC), Madrid, are available for making these experiments: HPPSC (High Pressure Planetary Simulation Chamber),
which working pressure range is 1-3000bar (extendable up to 10000 bars), the sample volume is 10ml. It has four ports for making different in situ analysis, including sapphire windows for optical measurements
MPPSC (Moderate-high pressure Planetary Simulation Chamber), which maximum working pressure is 300bar, the volume is variable up to 50ml due to a mobile piston. It also has a window for spectroscopic measurements
Both chambers are made of stainless steel and have automatic control system for temperature and pressure. Raman and ultraviolet spectroscopy have been the main techniques used during the experiments.
HPPSCP
Hydrauliccompressor
Pressure transducer
HighPressureChamber
CO2
V1
V2
V3
Thermalfluid
Sapphire window
Thermocouple
Pressure transducer
P
Opticsystem
Laser CCD
Monochromator
Optic Fibers
MPPSC
CLATHRATE FORMATION FROM MGSO4 SOLUTIONSThere were not any experiment on CO2-clathrates formed from MgSO4-H2O in the literature
Salts are inhibitors of clathrate formation. Sulfates affects less than chlorides
Theoretical models shows a decrease of temperature of 3-4 degrees in the dissociation line
PROCEDURE FOR CLATHRATE FORMATIONClathrates are formed from a solution saturated in CO2 and different concentration of MgSO4 (5, 10, 17% weight)
Formation cycle: ABCD
Analysis of the kinetic of clathrate formation by Raman
Calibration: evolution of the brine using the SO4
2- peaks
1000 1500 2000 2500 3000 3500
0
500
1000
1500
960 970 980 990 1000 1010
0
500
1000
1500
Inte
nsity
(a.u
.)
Raman Shift (cm-1)
2.5% 5% 7.5% 10% 13.5% 17%
RAMAN MONITORING OF CLATHRATE FORMATION
265 270 275 280 285 290 2950
20
40
60
80
100
10% MgSO4 exp
10% MgSO4 theor
H+I+CO2(g)
H+I+CO2(l)
H+Lw+CO2(l)
P (b
ar)
T (K)
H+Lw+CO2(g)
EVOLUTION OF THE SOLUTION
900 1000 1200 1300 14000
1000
2000
30000
1000
2000
30000
1000
2000
SO2-4
Raman Shift (cm-1)
CO2 gas
Inte
nsity
(a.u
.)
SO2-4
CO2 clathrate
CO2 dissolved
1000 1500 2000 2500 3000 3500
900 1000 1100 1200 1300 1400
Inte
nsity
(a.u
.)
Raman Shift (cm-1)
1000 1500 2000 2500 3000 3500
900 1000 1100 1200 1300 1400
Raman Shift (cm-1)
CO2 bands (1280 and 1380 cm-1): Fermi bands are displaced, hot bands disappear
SO42- band change during the formation
of clathrates. It increases in the first moment, and finally decreases if saturation of the salt produce its precipitation
APPLICATION TO EUROPAFormation of clathrates in aqueous reservoir may produce the fractional differentiation of the cryomagmatic liquids
A: H2O-CO2-MgSO4 cryomagmatic chamberB: CO2 clathrates crystallizeC: Brine concentrates and separates, salts can precipitateD: Dissociation by P/T change. Clean H2O-CO2 cryomagmas can erupt
DCBA
SOLUBILITY OF CO2 IN SALTY SOLUTIONSThere are solubility data of CO2 in some brines at different pressures (chlorides, Na-sulfate) but not MgSO4 and just to relative high pressures
273 323 373 423 4730
2
4
6
8
10
mCO2=0.05 y mNS=1Linear (m-CO2=0.05 y mNS=1)mCO2=0.1 y mNS=1Linear (mCO2=0.1 y mNS=1)
Temperature (K)
Pres
sure
(MPa
)
0 1 2 3 4 5 6 7 8 9 100
0.5
1
1.5
2
2.5
3Solubility CO2 in a brine 12%Na2SO4
313
%w
ight
CO
2
Pressure (MPa)
273 323 373 423 4730
2
4
6
8
10mCO2=0.05 y mNS=2Linear (m-CO2=0.05 y mNS=2)Linear (m-CO2=0.05 y mNS=2)mCO2=0.1 y mNS=2
Temperature (K)
Pres
sure
(MPa
)
0 1 2 3 4 5 6 7 8 9 100
0.20.40.60.8
11.21.41.6
f(x) = − 0.005993654 x² + 0.2028157487 xf(x) = − 0.00893140549 x² + 0.248512405 x
f(x) = 0
313
Pressure (MPa)
%w
eigh
t CO
2
Solubility CO2 in a brine22% Na2SO4
EFFECT OF PRESSURE ON THE SOLUBILITY OF CO2 IN MGSO4 Dependence of the CO2 solubility in a 3% MgSO4 solution with pressure. This analysis have been done for different concentrations of sulfate
1000 1200 1400 1600
0.0
0.2
0.4
0.6
0.8
1.0
1300 1350 1400 1450 1500
0,0
0,1
0,2
60 bar 49 bar 40 bar 31 bar 22 bar 13 bar
Inte
nsity
(a.u
.)
Raman Shift (cm-1)
APPLICATION TO EUROPA
200 400 600 800 1000 1200 1400
-50-45-40-35-30-25-20-15-10
-50
m=0, T=273, CO2=3
m=0, T=298, CO2=3
m=1, T=273, CO2=3
m=1, T=313, CO2=3
m=1, T=323, CO2=3
m=1, T=353, CO2=3
m=2, T=273, CO2=3
m=2, T=313, CO2=3
m=2, T=333, CO2=3
m=2, T=353, CO2=3
m=1, T=273, CO2=5
m=1, T=273, CO2=5
m=1, T=273, CO2=10
Density of the cryomagma Na2SO4-CO2-H2O (Kg/m3)
0 5 10 15 20 25 301000
1100
1200
1300MgSO4
Na2SO4
% weight
r (kg/m3
)
0.01
0.06
Pre
ssur
e (M
Pa)
Buoyancy of briny cryomagmas and style of the eruption
Cryomagmas charged in gas can suffer exolution if they depressurize to form a foam that has low density
APLICATION TO EUROPAFollowing the terrestrial models, if volume% of gas is up to 75% of cryomagma, fragmentation would occur and the cryomagma could erupt violently to the surface
mNa2SO4 T d(m)0 273 0.430 298 0.461 273 0.471 313 0.551 323 0.571 353 0.622 273 0.522 313 0.62 333 0.632 353 0.67
Depth where the pressure for fragmentation can be reached in the crust of Europa
CONCLUSIONS
Cryomagmatic liquids have astrobiology interest
The evolution of cryomagmas from the interior of Europa may occur by several processes (final products, including biosignatures could be the exposed materials at the surface)
Simulation in laboratory may help to understand how these processes occur Clathration may be a style of differentiation in icy
satellites Exolution of gases in sulfate-rich aqueous
cryomagmas may derive in briny cryomagma buoyancy and explosive cryovolcanism