title: Tropical to mid-latitude snow and ice accumulation, flow and glaciation on Mars.
abstract: Images from the Mars Express HRSC (High-Resolution Stereo Camera) of debris aprons at the base of massifs in eastern Hellas reveal numerous concentrically ridged lobate and pitted features and related evidence of extremely ice-rich glacier-like viscous flow and sublimation. Together with new evidence for recent ice-rich rock glaciers at the base of the Olympus Mons scarp superposed on larger Late Amazonian debris-covered piedmont glaciers, we interpret these deposits as evidence for geologically recent and recurring glacial activity in tropical and mid-latitude regions of Mars during periods of increased spin-axis obliquity when polar ice was mobilized and redeposited in microenvironments at lower latitudes. The data indicate that abundant residual ice probably remains in these deposits and that these records of geologically recent climate changes are accessible to future automated and human surface exploration.
authors.affiliation: Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA. james_head@brown.edu
authors.forename: J W
authors.initials: JW
authors.lastname: Head
authors.forename: G
authors.initials: G
authors.lastname: Neukum
authors.forename: R
authors.initials: R
authors.lastname: Jaumann
authors.forename: H
authors.initials: H
authors.lastname: Hiesinger
authors.forename: E
authors.initials: E
authors.lastname: Hauber
authors.forename: M
authors.initials: M
authors.lastname: Carr
authors.forename: P
authors.initials: P
authors.lastname: Masson
authors.forename: B
authors.initials: B
authors.lastname: Foing
authors.forename: H
authors.initials: H
authors.lastname: Hoffmann
authors.forename: M
authors.initials: M
authors.lastname: Kreslavsky
authors.forename: S
authors.initials: S
authors.lastname: Werner
authors.forename: S
authors.initials: S
authors.lastname: Milkovich
authors.forename: S
authors.initials: S
authors.lastname: van Gasselt
mesh_terms: D002980:Climate; D005118:Extraterrestrial Environment / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry; D046448:Ice Cover; D018535:Mars; D010781:Photography; D012914:Snow; D013026:Space Flight; D013997:Time Factors