Abstract
The surface of Ganymede is characterized by dark and light terrains.
Light terrain, covering two thirds of the surface, is retained to be
younger and resulted from resurfacing events, likely correlated to a
global expansion of Ganymede [1]. It is typically characterized by
several sets of subparallel troughs and ridges, called grooves. They
highly modify the dark terrain and the other pre-existing features.
Since these areas display two different superposed spacing scales,
grooves have been interpreted as the product of extensional tectonism
[2] and two different faulting styles have been recognized
(horst-graben and domino) [3]. Nevertheless, the stratigraphical
relationship, the required conditions to the grooves’ origin and the
tectonic mechanisms are still objects of debate. In preparation of the
ESA Juice Mission, we are producing DEMs of extended areas of the
surface of Ganymede, using both Galileo and Voyager imagery. We use the
open-source suite of tools NASA Ames Stereo Pipeline (ASP) [4], by
using the photoclinometry-based “shape-from-shading” (SfS) tool. Since
SfS needs an input DEM generated preferably with stereo images, and we
do not have such data in this area of Ganymede, we used the methodology
proposed by Lesage et al. 2021 [5]. Figure 1 shows an example of
Digital Elevation Model using a Galileo image (EDR 2878r, with a
resolution of 151 m/px) of Anshar Sulcus (167.40° E, 11.50° N). The DEM
clearly shows the height variations of the ridge and trough systems
included in the study area. These novel Digital Elevation Models can
provide new insights on the geological processes of Ganymede.
Acknowledgments GM acknowledges support from the Italian Space Agency
(contract ASI/2018-25-HH.0). References [1] Pappalardo R.T., et al.,
2004. Jupiter: The Planet, Satellites and Magnetosphere, 2:363. [2]
Prockter L.M. et al.,2010. Space Sci Rev 153:63-111 [3] Pizzi A. et
al., 2017. Icarus 288: 148-159 [4] Beyer, R. A. et al., (2018),
Science, 5. [5] Lesage E. et al. (2021), Icarus, 114373.