title: Bright and dark polar deposits on Mercury: evidence for surface volatiles.
abstract: Measurements of surface reflectance of permanently shadowed areas near Mercury's north pole reveal regions of anomalously dark and bright deposits at 1064-nanometer wavelength. These reflectance anomalies are concentrated on poleward-facing slopes and are spatially collocated with areas of high radar backscatter postulated to be the result of near-surface water ice. Correlation of observed reflectance with modeled temperatures indicates that the optically bright regions are consistent with surface water ice, whereas dark regions are consistent with a surface layer of complex organic material that likely overlies buried ice and provides thermal insulation. Impacts of comets or volatile-rich asteroids could have provided both dark and bright deposits.
authors.affiliation: NASA Goddard Space Flight Center, Code 698, Greenbelt, MD 20771, USA. gregory.a.neumann@nasa.gov
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Neumann
authors.forename: John F
authors.initials: JF
authors.lastname: Cavanaugh
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Sun
authors.forename: Erwan M
authors.initials: EM
authors.lastname: Mazarico
authors.forename: David E
authors.initials: DE
authors.lastname: Smith
authors.forename: Maria T
authors.initials: MT
authors.lastname: Zuber
authors.forename: Dandan
authors.initials: D
authors.lastname: Mao
authors.forename: David A
authors.initials: DA
authors.lastname: Paige
authors.forename: Sean C
authors.initials: SC
authors.lastname: Solomon
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Ernst
authors.forename: Olivier S
authors.initials: OS
authors.lastname: Barnouin