Ménec Fossae on Europa: A Strike-Slip Tectonics Origin above a possible
Shallow Water Reservoir
Abstract
Faults and fractures may emplace fresh material onto Europa’s surface,
originating from shallow reservoirs within the ice shell or directly
from the subsurface ocean. Ménec Fossae is a region of particular
interest, as it displays, within a relatively small area, the
interaction of several geological features such as bands, double ridges,
chaotic terrains, and fossae. These features might affect the
emplacement of buried material and subsequent exposure of fresh
volatiles, prime targets for the upcoming JUICE and Europa Clipper
missions in order to assess Europa’s astrobiological potential. Previous
studies already revealed that a deep central trough is present at Ménec
Fossae, flanked by several subparallel minor troughs and by few
asymmetrical scarps with lobate planforms. The presence of such features
has motivated this study, given its potential to provide clear
indications on the tectonic regime involved. Through detailed
geomorphological-structural mapping on Galileo Solid State Imager data
and terrain analysis on Digital Terrain Models, we could develop a novel
hypothesis on the formation mechanisms that might have been involved in
the study area. We propose that Ménec Fossae has been shaped by
transtensional (strike-slip with a major extensional component) tectonic
activity, as indicated by the orientation and relationship of the
tectonic features present. The shear heating related to such a tectonic
setting possibly led to the formation of a shallow water reservoir, that
in turn could have generated the observed chaotic terrains, double
ridges, and fossae. These results strengthen the case for widely
distributed shallow water reservoirs within Europa’s ice shell.