title: Spectral properties of Titan's impact craters imply chemical weathering of its surface.
abstract: We examined the spectral properties of a selection of Titan's impact craters that represent a range of degradation states. The most degraded craters have rims and ejecta blankets with spectral characteristics that suggest that they are more enriched in water ice than the rims and ejecta blankets of the freshest craters on Titan. The progression is consistent with the chemical weathering of Titan's surface. We propose an evolutionary sequence such that Titan's craters expose an intimate mixture of water ice and organic materials, and chemical weathering by methane rainfall removes the soluble organic materials, leaving the insoluble organics and water ice behind. These observations support the idea that fluvial processes are active in Titan's equatorial regions.
authors.affiliation: Department of Physics and Space Sciences Florida Institute of Technology Melbourne Florida USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Neish
authors.affiliation: Department of Physics University of Idaho Moscow Idaho USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Barnes
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA.
authors.forename: C
authors.initials: C
authors.lastname: Sotin
authors.affiliation: Department of Physics University of Idaho Moscow Idaho USA.
authors.forename: S
authors.initials: S
authors.lastname: MacKenzie
authors.affiliation: Department of Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology Cambridge Massachusetts USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Soderblom
authors.affiliation: Laboratoire de Planétologie et Géodynamique, LPGNantes, CNRS UMR 6112, Université de Nantes Nantes France.
authors.forename: S
authors.initials: S
authors.lastname: Le Mouélic
authors.affiliation: United States Geological Survey, Astrogeology Science Center Flagstaff Arizona USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Kirk
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA.
authors.forename: B W
authors.initials: BW
authors.lastname: Stiles
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Malaska
authors.affiliation: Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) Université de Versailles Saint-Quentin Paris France.
authors.forename: A
authors.initials: A
authors.lastname: Le Gall
authors.affiliation: Lunar and Planetary Laboratory University of Arizona Tucson Arizona USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Brown
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA.
authors.forename: K H
authors.initials: KH
authors.lastname: Baines
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA.
authors.forename: B
authors.initials: B
authors.lastname: Buratti
authors.affiliation: United States Geological Survey Denver Colorado USA.
authors.forename: R N
authors.initials: RN
authors.lastname: Clark
authors.affiliation: Department of Astronomy Cornell University Ithaca New York USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Nicholson
keywords: Titan; erosion and weathering; impact cratering