Search Publications
Depth of the Martian cryosphere: Revised estimates and implications for the existence and detection of subpermafrost groundwater
Heggy, Essam; Clifford, Stephen M.; Lasue, Jeremie +3 more
The Martian cryosphere is defined as that region of the crust where the temperature remains continuously below the freezing point of water. Previous estimates of its present thickness have ranged from ∼2.3-4.7 km at the equator to ∼6.5-12.5 km at the poles. Here we revisit these calculations, review some of the assumptions on which they were based…
Mineralogy and stratigraphy of phyllosilicate-bearing and dark mantling units in the greater Mawrth Vallis/west Arabia Terra area: Constraints on geological origin
Bibring, J. -P.; Poulet, F.; Bishop, J. L. +13 more
Analyses of MRO/CRISM images of the greater Mawrth Vallis region of Mars affirm the presence of two primary phyllosilicate assemblages throughout a region ∼1000 × 1000 km. These two units consist of an Fe/Mg-phyllosilicate assemblage overlain by an Al-phyllosilicate and hydrated silica assemblage. The lower unit contains Fe/Mg-smectites, sometimes…
Water ice at low to midlatitudes on Mars
Mustard, John; Forget, François; Vincendon, Mathieu
In this paper, we analyze water ice occurrences at the surface of Mars using near-infrared observations, and we study their distribution with a climate model. Latitudes between 45°S and 50°N are considered. Data from the Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Actitité and the Compact Reconnaissance Imaging Spectrometer for Mars a…
Nightside ionosphere of Mars: Radar soundings by the Mars Express spacecraft
Gurnett, D. A.; Němec, F.; Morgan, D. D. +1 more
We present results of a survey of the nightside ionosphere of Mars as observed by Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on board the Mars Express spacecraft. The occurrence rate of the nightside ionosphere is studied as a function of solar zenith angle (SZA), magnetic field magnitude, and magnetic field inclination. …
Spectral and stratigraphic mapping of hydrated sulfate and phyllosilicate-bearing deposits in northern Sinus Meridiani, Mars
Arvidson, R. E.; Morris, R. V.; Poulet, F. +7 more
We present detailed stratigraphic and spectral analyses that focus on a region in northern Sinus Meridiani located between 1°N to 5°N latitude and 3°W to 1°E longitude. Several stratigraphically distinct units are defined and mapped using morphologic expression, spectral properties, and superposition relationships. Previously unreported exposures …
Sinuous gullies on Mars: Frequency, distribution, and implications for flow properties
Mangold, N.; Ansan, V.; Mangeney, A. +4 more
Recent gullies on Mars are suspected to be the result of liquid-water-bearing flows. A formation from wet flows has been challenged by studies invoking granular (dry) flows. Our study focuses on the sinuous shapes observed for some of the recent Martian gullies. Sinuous gullies are found in locations and slopes (of 10°-15°) similar to straight gul…
Stratigraphy of hydrated sulfates in the sedimentary deposits of Aram Chaos, Mars
Murchie, Scott L.; Mustard, John F.; Arvidson, Raymond E. +8 more
Sedimentary deposits within the 280 km wide crater containing Aram Chaos (∼3°N, 339°E) have been differentially eroded by wind to expose a stratigraphic column 900-1000 m thick that unconformably overlies the chaos bedrock. A detailed stratigraphic and mineralogical description of the deposits is presented based on data from the Mars Reconnaissanc…
Late Noachian to Hesperian climate change on Mars: Evidence of episodic warming from transient crater lakes near Ares Vallis
Muller, Jan-Peter; Gupta, Sanjeev; Kim, Jung-Rack +3 more
The Ares Vallis region is surrounded by highland terrain containing both degraded and pristine large impact craters that suggest a change in climate during the Late Noachian-Early Hesperian, from warmer, wetter conditions to colder, dryer conditions. However, the regional occurrence of Hesperian-age crater outlet channels indicates that this perio…
Internal structure of Planum Boreum, from Mars advanced radar for subsurface and ionospheric sounding data
Plaut, J. J.; Safaeinili, A.; Aharonson, O. +1 more
An investigation of the internal structure of the ice-rich Planum Boreum (PB) deposit at the north pole of Mars is presented, using 178 orbits of Mars advanced radar for subsurface and ionospheric sounding data. For each radargram, bright, laterally extensive surface and subsurface reflectors are identified and the time delay between them is conve…
Rift zone volcanism and associated cinder cone field in Utopia Planitia, Mars
Neukum, G.; Wagner, R.; Lanz, J. K. +2 more
We analyzed a small cone field in SW Utopia Planitia that shows striking similarities to volcanic rift zones on Earth. This is of particular interest as the study area lies off any of the volcanic centers of Mars in the northern hemisphere lowlands and is surrounded by material of the Amazonian aged Vastitas Borealis Formation (VBF). We believe th…