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SUMMARY:Mass transport through Europa’s ice shell and the habitability o
 f Europa’s internal ocean - Professor Marc Hesse\, University of Texas
DTSTART:20220927T110000Z
DTEND:20220927T120000Z
UID:TALK182273@talks.cam.ac.uk
CONTACT:Catherine Pearson
DESCRIPTION:Jupiter’s moon Europa is thought to have an ocean beneath it
 s ice shell and the habitability of this internal ocean may depend on the 
 availability of redox gradients. Downward transport of radiolytic material
 s produced at the surface through the ice shell likely sets the flux of ox
 idants\ninto the ocean. Astronomical observations suggest that Europa’s 
 near surface regolith contains 1014 to 1018 mol of O2 and likely other oxi
 dants. Today I will discuss recent work in my group on three different pot
 ential transport mechanism for the oxidants through the ice shell: Convect
 ive\noverturn\, brine percolation and impacts. Due to the strong temperatu
 re dependence of the thermal conductivity the ice-shell has very thick con
 ductive lid that prevents the transport of oxidants through the ice by con
 vective overturn. A second process is the drainage of large volumes of\nne
 ar-surface brines beneath chaos terrains. I argue that these brines percol
 ate readily and can potentially transport surface-oxidants into the ocean 
 at a rate of 106 to 1010 mol/yr. Finally\, I discuss the effect of impacts
  on mass transport through the ice. We have shown that impacts do\nnot nee
 d to penetrate the ice shell to generate vertical mass transport. The foun
 dering of impact generated brines though the ice provides a potential mech
 anism to bring oxidants into the ocean at a rate of 101 to 105 kg/yr. Assu
 ming sufficient production of reductants due to weathering of Europa’s s
 eafloor\, our estimated oxidant fluxes are deemed sufficient to sustain pr
 imitive life in Europa’s internal ocean. Our simulations also imply that
  large volumes of near surface brine are not be stable in long timescales\
 , a hypothesis that is testable by NASA’s Europa Clipper mission.\n
LOCATION:Open Plan Area\, BP Institute\, Madingley Rise CB3 0EZ
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