Search Publications
Planetary surface dating from crater size-frequency distribution measurements: Poisson timing analysis
Michael, G. G.; Kneissl, T.; Neesemann, A.
The predictions of crater chronology models have customarily been evaluated by dividing a crater population into discrete diameter intervals, plotting the crater density for each, and finding a best-fit model isochron, with the uncertainty in the procedure being assessed using 1/√n estimates, where n is the number of craters in an interval. This a…
Observations of an aeolian landscape: From surface to orbit in Gale Crater
Day, Mackenzie; Kocurek, Gary
Landscapes derived solely from aeolian processes are rare on Earth because of the dominance of subaqueous processes. In contrast, aeolian-derived landscapes should typify Mars because of the absence of liquid water, the long exposure times of surfaces, and the presence of wind as the default geomorphic agent. Using the full range of available orbi…
Observations and modeling of northern mid-latitude recurring slope lineae (RSL) suggest recharge by a present-day martian briny aquifer
Michaels, Timothy I.; Hanley, Jennifer; Grimm, Robert E. +1 more
Recurring slope lineae (RSL) are narrow (0.5-5 m) dark features on Mars that incrementally lengthen down steep slopes, fade in colder seasons, and recur annually. These features have been identified from the northern to southern mid-latitudes. Here, we describe how observations of northern mid-latitude RSL in northern Chryse Planitia and southwest…
Daily global mapping of Mars ozone column abundances with MARCI UV band imaging
Smith, Michael D.; Wolff, Michael J.; Lefèvre, Franck +3 more
Since November of 2006, The Mars Color Imager (MARCI) onboard the Mars Reconnaissance Orbiter (MRO) has obtained multiple-filter daily global images of Mars centered upon a local time (LT) of 3 pm. Ultraviolet imaging bands placed within (260 nm) and longward (320 nm) of Hartley band (240-300 nm) ozone (O3) absorption support retrievals…
SPICAM observations and modeling of Mars aurorae
Bertaux, Jean-Loup; Stiepen, Arnaud; Gérard, Jean-Claude +4 more
Martian aurorae have been detected with the SPICAM instrument on board Mars Express both in the nadir and the limb viewing modes. In this study, we focus on three limb observations to determine both the altitudes and the intensities of the auroral emissions. The CO (a3Π-X1Σ) Cameron bands between 190 and 270 nm, the CO (A
Photogeologic mapping and the geologic history of the Hellas basin floor, Mars
Hiesinger, H.; Bernhardt, H.; Ivanov, M. A. +3 more
The Hellas basin on Mars is the second-largest topographically well-defined impact structure in the Solar System and has repeatedly been interpreted as a major sink of volcanic, glacio-fluvial and eolian materials. Based on established guidelines for planetary mapping, we compiled a comprehensive photogeological map of Hellas Planitia, i.e., the H…
Are the Dorsa Argentea on Mars eskers?
Conway, Susan J.; Butcher, Frances E. G.; Arnold, Neil S.
The Dorsa Argentea are an extensive assemblage of ridges in the southern high latitudes of Mars. They have previously been interpreted as eskers formed by deposition of sediment in subglacial meltwater conduits, implying a formerly more extensive south polar ice sheet. In this study, we undertake the first large-scale statistical analysis of aspec…
Wavelength dependence of scattering properties in the VIS-NIR and links with grain-scale physical and compositional properties
Schmidt, F.; Ehlmann, B. L.; Pilorget, C. +2 more
Surface scattered sunlight carries important information about the composition and microtexture of surface materials, thus enabling tracing back the geological and climatic processes that occurred on the planetary body. Here we perform laboratory spectro-goniometric measurements of granular samples (45-75 µ m fraction) with different composi…
Morphologic evidence of subsurface sediment mobilization and mud volcanism in Candor and Coprates Chasmata, Valles Marineris, Mars
Okubo, Chris H.
Populations of distinctive knobs, rings and lobate structures are observed in the Candor and Coprates Chasmata regions of Mars. To interpret the formation mechanisms of these landforms, I investigate their morphologies, facies, superposition and crosscutting relationships using data from the High Resolution Imaging Science Experiment (HiRISE) and …
Topographic measurements of slope streaks on Mars
Head, James W.; Brusnikin, Eugene S.; Kreslavsky, Mikhail A. +4 more
Slope streaks are enigmatic, actively forming albedo features occurring on slopes in high-albedo, low-thermal-inertia, dust-rich equatorial regions on Mars. They are a specifically martian phenomenon with no direct analogs on the Earth. Their morphology suggests that the streaks are initiated at their upslope tips and propagate down to their termi…