title: A closer look at water-related geologic activity on Mars.
abstract: Water has supposedly marked the surface of Mars and produced characteristic landforms. To understand the history of water on Mars, we take a close look at key locations with the High-Resolution Imaging Science Experiment on board the Mars Reconnaissance Orbiter, reaching fine spatial scales of 25 to 32 centimeters per pixel. Boulders ranging up to approximately 2 meters in diameter are ubiquitous in the middle to high latitudes, which include deposits previously interpreted as finegrained ocean sediments or dusty snow. Bright gully deposits identify six locations with very recent activity, but these lie on steep (20 degrees to 35 degrees) slopes where dry mass wasting could occur. Thus, we cannot confirm the reality of ancient oceans or water in active gullies but do see evidence of fluvial modification of geologically recent mid-latitude gullies and equatorial impact craters.
authors: Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. mcewen@lpl.arizona.edu
authors: A S
authors: AS
authors: McEwen
authors: C J
authors: CJ
authors: Hansen
authors: W A
authors: WA
authors: Delamere
authors: E M
authors: EM
authors: Eliason
authors: K E
authors: KE
authors: Herkenhoff
authors: L
authors: L
authors: Keszthelyi
authors: V C
authors: VC
authors: Gulick
authors: R L
authors: RL
authors: Kirk
authors: M T
authors: MT
authors: Mellon
authors: J A
authors: JA
authors: Grant
authors: N
authors: N
authors: Thomas
authors: C M
authors: CM
authors: Weitz
authors: S W
authors: SW
authors: Squyres
authors: N T
authors: NT
authors: Bridges
authors: S L
authors: SL
authors: Murchie
authors: F
authors: F
authors: Seelos
authors: K
authors: K
authors: Seelos
authors: C H
authors: CH
authors: Okubo
authors: M P
authors: MP
authors: Milazzo
authors: L L
authors: LL
authors: Tornabene
authors: W L
authors: WL
authors: Jaeger
authors: S
authors: S
authors: Byrne
authors: P S
authors: PS
authors: Russell
authors: J L
authors: JL
authors: Griffes
authors: S
authors: S
authors: Martínez-Alonso
authors: A
authors: A
authors: Davatzes
authors: F C
authors: FC
authors: Chuang
authors: B J
authors: BJ
authors: Thomson
authors: K E
authors: KE
authors: Fishbaugh
authors: C M
authors: CM
authors: Dundas
authors: K J
authors: KJ
authors: Kolb
authors: M E
authors: ME
authors: Banks
authors: J J
authors: JJ
authors: Wray
mesh_terms: D005118:Extraterrestrial Environment; D055593:Geological Phenomena; D005844:Geology; D018535:Mars; D014867:Water
chemical_list: D014867:Water