Mars Obliquity Through Deep Time: New Constraints From the Bombardment Compass

Late Amazonian Ice Survival in Kasei Valles, Mars

“…Statistical density modeling of 20,000 possible solutions for Mars's orbital history indicates Mars's mean obliquity is ∼37.62° over the last 4 Gyr, but that it may have approached values as high as 90° (Laskar et al., 2004). Although the measurement of elliptical craters suggests this may have only happened a handful of times since the Noachian (Holo et al., 2019), at such high obliquity, volatile redistribution may plausibly have extended beyond the mid‐latitudes toward the equatorial region. Indeed, several landforms other than GLDA depressions linked to glaciation at low latitudes have been reported, concentrated around the large volcanoes of the Tharsis province (Head et al., 2005; Milkovich et al., 2006; Murray et al., 2005; Scanlon et al., 2014; Shean et al., 2005; Sinha et al., 2017) and elsewhere (Gourronc et al., 2014).…”