Search Publications
Seasonal variability of the hydrogen exosphere of Mars
Halekas, J. S.
The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission measures both the upstream solar wind and collisional products from energetic neutral hydrogen atoms that precipitate into the upper atmosphere after their initial formation by charge exchange with exospheric hydrogen. By computing the ratio between the densities of these populations, we d…
Spectral properties of Martian and other planetary glasses and their detection in remotely sensed data
Mustard, John F.; Dyar, M. Darby; Cannon, Kevin M. +3 more
Thirty silicate glasses were synthesized as realistic analogs to those expected to exist on Mars, the Moon, and Mercury. Samples were measured using visible/near-infrared and Mössbauer spectroscopy to determine the effects of varying bulk chemistry, oxygen fugacity, and temperature on spectral properties. For Martian glasses, the fO2 du…
Acidic weathering of basalt and basaltic glass: 1. Near-infrared spectra, thermal infrared spectra, and implications for Mars
Christensen, Philip R.; Cloutis, Edward A.; Mann, Paul +2 more
Acid-leached rinds and coatings occur in volcanic environments on Earth and have been identified using orbital spectroscopy on Mars, but their development is poorly understood. We simulated long-term open-system acidic weathering in a laboratory by repeatedly rinsing and submerging crystalline and glassy basalts in pH 1 and pH 3 acidic solutions f…
Radar sounding of Lucus Planum, Mars, by MARSIS
Rossi, Angelo Pio; Orosei, Roberto; Cartacci, Marco +6 more
Lucus Planum, extending for a radius of approximately 500 km around 181°E, 5°S, is part of the Medusae Fossae Formation (MFF), a set of several discontinuous deposits of fine-grained, friable material straddling across the Martian highland-lowland boundary. The MFF has been variously hypothesized to consist of pyroclastic flows, pyroclastic airfal…
Flank vents and graben as indicators of Late Amazonian volcanotectonic activity on Olympus Mons
Christensen, P. R.; Peters, S. I.
Previous studies have focused on large-scale features on Olympus Mons, such as its flank terraces, the summit caldera complex, and the basal escarpment and aureole deposits. Here we identify and characterize previously unrecognized and unmapped small scale features to help further understand the volcanotectonic evolution of this enormous volcano. …
The anatomy of a wrinkle ridge revealed in the wall of Melas Chasma, Mars
Andrews-Hanna, Jeffrey C.; Cole, Hank M.
Wrinkle ridges are among the most common tectonic structures on the terrestrial planets and provide important records of the history of planetary strain and geodynamics. The observed broad arches and superposed narrow wrinkles are thought to be the surface manifestation of blind thrust faults, which terminate in near-surface volcanic sequences and…
The Evolution of Juventae Chasma, Valles Marineris, Mars: Progressive Collapse and Sedimentation
Hauber, E.; Rossi, A. P.; Flahaut, J. +3 more
Juventae Chasma is an isolated chasm located north of the interconnected chasms within Valles Marineris. It contains four separate interior layered deposit (ILD) mounds. We have combined layer measurements, as well as mineralogical data of the mounds with topographic data of the remaining chasm and the surrounding plateau. Our observations indicat…
Widespread exposure of Noachian phyllosilicates in the Margaritifer region of Mars: Implications for paleohydrology and astrobiological detection
Hynek, Brian M.; Thomas, Rebecca J.; Osterloo, Mikki M. +1 more
The best locations at which to detect evidence for early life on Mars are in materials formed in near-surface aqueous environments, particularly where this resulted in the deposition of minerals such as clays that are favorable to preservation of organics. The geological history of the Margaritifer region has resulted in exceptional potential to p…
The structural, stratigraphic, and paleoenvironmental record exposed on the rim and walls of Iazu Crater, Mars
Arvidson, R. E.; Murchie, S. L.; Zanetti, M. +2 more
Iazu is a 6.8 km diameter crater located 25 km south of Endeavour Crater in Meridiani Planum, Mars. The asymmetrical ejecta deposit and crater shape demonstrate that Iazu was formed by the impact of a projectile moving from west to east at 20 to 30° above the horizontal. The crater rim and walls expose an 115 m thick section of intact banded brigh…