title: Mars north polar deposits: stratigraphy, age, and geodynamical response.
abstract: The Shallow Radar (SHARAD) on the Mars Reconnaissance Orbiter has imaged the internal stratigraphy of the north polar layered deposits of Mars. Radar reflections within the deposits reveal a laterally continuous deposition of layers, which typically consist of four packets of finely spaced reflectors separated by homogeneous interpacket regions of nearly pure ice. The packet/interpacket structure can be explained by approximately million-year periodicities in Mars' obliquity or orbital eccentricity. The observed approximately 100-meter maximum deflection of the underlying substrate in response to the ice load implies that the present-day thickness of an equilibrium elastic lithosphere is greater than 300 kilometers. Alternatively, the response to the load may be in a transient state controlled by mantle viscosity. Both scenarios probably require that Mars has a subchondritic abundance of heat-producing elements.
authors.affiliation: Southwest Research Institute, Boulder, CO 80302, USA. roger@boulder.swri.edu
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Phillips
authors.forename: Maria T
authors.initials: MT
authors.lastname: Zuber
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Smrekar
authors.forename: Michael T
authors.initials: MT
authors.lastname: Mellon
authors.forename: James W
authors.initials: JW
authors.lastname: Head
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Tanaka
authors.forename: Nathaniel E
authors.initials: NE
authors.lastname: Putzig
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Milkovich
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Campbell
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Plaut
authors.forename: Ali
authors.initials: A
authors.lastname: Safaeinili
authors.forename: Roberto
authors.initials: R
authors.lastname: Seu
authors.forename: Daniela
authors.initials: D
authors.lastname: Biccari
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Carter
authors.forename: Giovanni
authors.initials: G
authors.lastname: Picardi
authors.forename: Roberto
authors.initials: R
authors.lastname: Orosei
authors.forename: P Surdas
authors.initials: PS
authors.lastname: Mohit
authors.forename: Essam
authors.initials: E
authors.lastname: Heggy
authors.forename: Richard W
authors.initials: RW
authors.lastname: Zurek
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Egan
authors.forename: Emanuele
authors.initials: E
authors.lastname: Giacomoni
authors.forename: Federica
authors.initials: F
authors.lastname: Russo
authors.forename: Marco
authors.initials: M
authors.lastname: Cutigni
authors.forename: Elena
authors.initials: E
authors.lastname: Pettinelli
authors.forename: John W
authors.initials: JW
authors.lastname: Holt
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Leuschen
authors.forename: Lucia
authors.initials: L
authors.lastname: Marinangeli