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Radar evidence for ice in lobate debris aprons in the mid-northern latitudes of Mars
Head, James W.; Frigeri, Alessandro; Seu, Roberto +5 more
Subsurface radar sounding data indicate that lobate debris aprons found in Deuteronilus Mensae in the mid-northern latitudes of Mars are composed predominantly of water ice. The position in time delay and the relatively low amount of signal loss of the apparent basal reflectors below the debris aprons indicate that aprons contain only a minor comp…
Phyllosilicates and sulfates at Endeavour Crater, Meridiani Planum, Mars
Arvidson, R. E.; Mustard, J. F.; Wray, J. J. +5 more
Phyllosilicates have been identified on the Martian surface from orbit, and are hypothesized to have formed under wet, non-acidic conditions early in the planet's history. Exposures of these minerals have not yet been examined by a landed mission. Using Mars Reconnaissance Orbiter data, we report the detection of phyllosilicate-bearing outcrops th…
Ionospheric storms on Mars: Impact of the corotating interaction region
Barabash, S.; Lundin, R.; Woch, J. +5 more
Measurements made by the ASPERA-3 and MARSIS experiments on Mars Express have shown, for the first time, that space weather effects related to the impact of a dense and high pressure solar wind (corotating interaction region) on Mars cause strong perturbations in the martian induced magnetosphere and ionosphere. The magnetic barrier formed by pile…
Amazonian-aged fluvial valley systems in a climatic microenvironment on Mars: Melting of ice deposits on the interior of Lyot Crater
Head, J. W.; Dickson, J. L.; Fassett, C. I.
Valley networks, regional drainage patterns suggesting liquid water stability at the surface, are confined to early in the history of Mars (the Noachian/Hesperian boundary and before), prior to a major climate transition to the hyperarid cold conditions of the Amazonian. Several later fluvial valley systems have been documented in specific Hesperi…
Atmospheric origin of cold ion escape from Mars
Barabash, S.; Lundin, R.; Holmström, M. +4 more
Cold ionospheric ions dominate the plasma escape from Mars. The flow pattern versus altitude, latitude and local time suggests a fairly symmetric transport of ionospheric plasma from the dayside into the nightside/tail region of Mars. An interesting aspect of the plasma escape from Mars is the large abundance of molecular ions, implying that the o…
Positive identification of lake strandlines in Shalbatana Vallis, Mars
Hynek, Brian M.; Di Achille, Gaetano; Searls, Mindi L.
Remote sensing studies of possible Martian paleolakes have hinted at the presence of paleoshorelines on Mars, although have never been unequivocally identified. Recently-acquired sub-meter scale High Resolution Imaging Science Experiment (HiRISE) images of Shalbatana Vallis reveal the first direct evidence of strandlines along a delta formed withi…
Long-lived auroral structures and atmospheric losses through auroral flux tubes on Mars
Barabash, S.; Lundin, R.; Woch, J. +2 more
The ASPERA-3 observations of electron and ion fluxes over the regions dominated by crustal magnetic fields show the existence of long-lived and active aurora-type magnetic flux tubes with a width of 20-150 km. The activity manifests itself by large electron energy fluxes (≥10-4 W/m2) and strong distortions in the upper (350-4…
Is the Martian water table hidden from radar view?
Gurnett, D. A.; Farrell, W. M.; Plaut, J. J. +4 more
Mars may possess a global sub-surface groundwater table as an integral part of its current hydrological system. However, the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) onboard the Mars Express (MEx) spacecraft has yet to make a definitive detection of such a body of liquid water. In this work, we quantify the conditions t…
Association of phyllosilicates and the inverted channel in Miyamoto crater, Mars
Wiseman, S. M.; McGuire, P. C.; Marzo, G. A. +4 more
The western floor of the Miyamoto crater in Sinus Meridiani on Mars exhibits both geomorphic and spectral evidence for aqueous history. It contains a sinuous and narrow ridge that is interpreted to be an inverted channel and is suggestive of past fluvial activity. Phyllosilicates occur in materials that are proximal to the paleochannel, but are no…
“Hook” structure in MARSIS ionogram and its interpretation
Wang, X. -D.; Zou, H.; Wang, J. -S. +1 more
MARSIS/MEX is a low frequency radar used to sound the ionosphere of Mars. In general the echo trace associated with reflections in nadir indicates an ionosphere with a main maximum electron density at typically about 130 km altitude, and a monotonously decreasing density with increasing altitude. Another maximum is sometimes detected at higher alt…