RT Journal Article
T1 Heat flow and thickness of a convective ice shell on Europa for grainsize-dependent rheologies
A1 Ruiz Pérez, Javier
A1 Álvarez Gómez, José Antonio
A1 Tejero López, Rosa
A1 Sánchez, Nieves
AB Although it is mostly accepted that the lower part of the ice shell of Europa is actively convective, there is still much uncertainty about the flowmechanism dominating the rheology of this convective layer, which largely depends on the grain size of the ice. In this work, we examined thermalequilibrium states in a tidally heated and strained convective shell, for two rheologies sensitive to grain size, grain boundary sliding and diffusioncreep. If we take a lower limit of 70 mWm−2 for the surface heat flow, according to some geological features observed, the ice grain size shouldbe less than 2 or 0.2 mm for grain boundary sliding or diffusion creep respectively. If in addition the thickness of the ice shell is constrained to afew tens of kilometers and it is assumed that the thickness of the convective layer is related to lenticulae spacing, then grain sizes between 0.2 and2 mm for grain boundary sliding, and between 0.1 and 0.2 mm for diffusion creep are obtained. Also, local convective layer thicknesses deducedfrom lenticulae spacing are more similar to those here derived for grain boundary sliding. Our results thus favor grain boundary sliding as thedominant rheology for the water ice in Europa’s convective layer, since this flow mechanism is able to satisfy the imposed constraints for a widerrange of grain sizes.
PB Elsevier Science B.V., Amsterdam
SN 0019-1035
YR 2007
FD 2007
LK https://hdl.handle.net/20.500.14352/49340
UL https://hdl.handle.net/20.500.14352/49340
LA eng
DS Docta Complutense
RD 1 may 2024