In addition fresh H2O–ice not covered yet by submicron particles show a distinct Fresnel reflection peak at 3.1 µm, which also changes its shape depending on the crystallinity of H2O ice (Hansen and McCord, 2004). The crystallinity of H2O ice is also expected to influence the wavelength positions of the H2O–ice absorptions, in particular in case of the LY364947 at 2 µm, shifting the band to longer wavelengths when the H2O–ice transforms from amorphous to crystalline H2O ice (Clark et al., 2012).
3. Overview of Tethys’ geological units
3.1. The pre-Cassini view of the geology of Tethys
Voyager images of Tethys, taken in the flybys in November 1980 (Voyager-1) and August 1981 (Voyager-2), revealed a generally densely cratered landscape and two major landmarks: the graben system of Ithaca Chasma and the 400-km large impact structure Odysseus. Voyager-2 returned images with the highest resolution primarily of the Saturn-facing hemisphere. The southern latitudes of the leading and trailing hemispheres as well as the south polar terrain could not be imaged by Voyager at sufficient resolution. Voyager-based geology of Tethys was described by Smith et al., 1981 and Smith et al., 1982, and Moore and Ahern (1983) and is briefly reviewed here.
3. Overview of Tethys’ geological units
3.1. The pre-Cassini view of the geology of Tethys
Voyager images of Tethys, taken in the flybys in November 1980 (Voyager-1) and August 1981 (Voyager-2), revealed a generally densely cratered landscape and two major landmarks: the graben system of Ithaca Chasma and the 400-km large impact structure Odysseus. Voyager-2 returned images with the highest resolution primarily of the Saturn-facing hemisphere. The southern latitudes of the leading and trailing hemispheres as well as the south polar terrain could not be imaged by Voyager at sufficient resolution. Voyager-based geology of Tethys was described by Smith et al., 1981 and Smith et al., 1982, and Moore and Ahern (1983) and is briefly reviewed here.