title: Quasi-periodic bedding in the sedimentary rock record of Mars.
abstract: Widespread sedimentary rocks on Mars preserve evidence of surface conditions different from the modern cold and dry environment, although it is unknown how long conditions favorable to deposition persisted. We used 1-meter stereo topographic maps to demonstrate the presence of rhythmic bedding at several outcrops in the Arabia Terra region. Repeating beds are approximately 10 meters thick, and one site contains hundreds of meters of strata bundled into larger units at a approximately 10:1 thickness ratio. This repetition likely points to cyclicity in environmental conditions, possibly as a result of astronomical forcing. If deposition were forced by orbital variation, the rocks may have been deposited over tens of millions of years.
authors.affiliation: Divison of Geological and Planetary Sciences, California Institute of Technology, 150-21, Pasadena, CA 91125, USA. klewis@gps.caltech.edu
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Lewis
authors.forename: Oded
authors.initials: O
authors.lastname: Aharonson
authors.forename: John P
authors.initials: JP
authors.lastname: Grotzinger
authors.forename: Randolph L
authors.initials: RL
authors.lastname: Kirk
authors.forename: Alfred S
authors.initials: AS
authors.lastname: McEwen
authors.forename: Terry-Ann
authors.initials: TA
authors.lastname: Suer
mesh_terms: D005118:Extraterrestrial Environment; D019015:Geologic Sediments; D018535:Mars