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Widespread surface weathering on early Mars: A case for a warmer and wetter climate
Mangold, Nicolas; Bibring, Jean-Pierre; Poulet, François +2 more
Early Mars (>3 Ga) underwent aqueous alteration as evidenced by fluvial/lacustrine morphologies and the recent discovery of widespread hydrous clays. Despite compelling evidence for diverse and localized aqueous environments, the possibility for sustained liquid water globally on the martian surface and over geological timescales is still highl…
Classification and analysis of candidate impact crater-hosted closed-basin lakes on Mars
Mustard, John F.; Goudge, Timothy A.; Head, James W. +2 more
We present a new catalog of 205 candidate closed-basin lakes contained within impact craters across the surface of Mars. These basins have an inlet valley that incises the crater rim and flows into the basin but no visible outlet valley, and are considered candidate closed-basin lakes; the presence of a valley flowing into a basin does not necessi…
Mars' water vapor mapping by the SPICAM IR spectrometer: Five martian years of observations
Montmessin, Franck; Trokhimovskiy, Alexander; Bertaux, Jean-Loup +4 more
The SPICAM IR instrument on the Mars Express mission continuously observes the water vapor in the martian atmosphere starting from 2004 in the 1.38-µm spectral band. The water vapor column abundance is retrieved from nadir observations to characterize its spatial, seasonal and interannual variations. A reference set of SPICAM water vapor col…
Variability of the hydrogen in the martian upper atmosphere as simulated by a 3D atmosphere-exosphere coupling
Lopez-Valverde, M. A.; Forget, F.; Chaufray, J. -Y. +4 more
We present the temporal variability of the atomic and molecular hydrogen density derived from a 3D General Circulation Model describing the martian atmosphere from the surface to the exobase. A kinetic exospheric model is used to compute the hydrogen density above the exobase. We use these models to study the diurnal and seasonal variations of the…
Persistent aeolian activity at Endeavour crater, Meridiani Planum, Mars; new observations from orbit and the surface
Johnson, Jeffrey R.; Chojnacki, Matthew; Moersch, Jeffrey E. +3 more
Aeolian-driven bedform activity is now known to occur in many regions of Mars, based on surface and orbital observation of contemporary martian ripple and dune mobility events. Many of these sites have only been monitored with sufficient resolution data for the last few Mars years, when the High Resolution Imaging Science Experiment (HiRISE) began…
Age determination of linear surface features using the Buffered Crater Counting approach - Case studies of the Sirenum and Fortuna Fossae graben systems on Mars
Platz, T.; Michael, G. G.; Walter, S. H. G. +1 more
Buffered Crater Counting (BCC) offers a possibility to determine ages of linear/curvilinear surface features that provide no or only very limited surface areas for the conventional crater counting approach. In this study we applied the BCC analysis to two tectonic fault systems, Fortuna Fossae and a subsection of Sirenum Fossae. We compared BCC re…
Mixtures of clays and sulfates within deposits in western Melas Chasma, Mars
Wray, James J.; Weitz, Catherine M.; Noe Dobrea, Eldar
We have utilized several data sets from multiple spacecraft that have been acquired over a continuous observation campaign across the southwestern Melas Chasma region of Mars. The blocky deposit observed on the chasma floor and on portions of the southern wallrock consists of mixtures of light- and medium-toned materials that exhibit displacement …
Dust devil height and spacing with relation to the martian planetary boundary layer thickness
Fenton, Lori K.; Lorenz, Ralph
In most remote and unmonitored places, little is known about the characteristics of daytime turbulent activity. Few processes render the optically transparent atmospheres of Earth and Mars visible; put more plainly, without clever instruments it is difficult to "see the unseen". To address this, we present a pilot study of images of martian dust d…
Orbital detection and implications of akaganéite on Mars
Le Deit, Laetitia; Carter, John; Loizeau, Damien +2 more
The martian surface bears the mineralogical record of ancient sub-surface and surface aqueous alteration environments. While most of the chemical alteration produced phyllosilicates, hydrated sulfates and chlorides, other less common compounds provide key constraints on localized geochemical settings, and help refine the geological evolution of th…
Sulfur in the early martian atmosphere revisited: Experiments with a 3-D Global Climate Model
Forget, François; Kerber, Laura; Wordsworth, Robin
Volcanic SO2 in the martian atmosphere has been invoked as a way to create a sustained or transient greenhouse during early martian history. Many modeling studies have been performed to test the feasibility of this hypothesis, resulting in a range of conclusions, from highly feasible to highly improbable. In this study we perform a wide…