Search Publications
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…
Sequence and relative timing of large lakes in Gale crater (Mars) after the formation of Mount Sharp
Mangold, Nicolas; Williams, Rebecca M. E.; Palucis, Marisa C. +6 more
The quantification of lake levels in Gale crater is important to define the hydrologic and climatic history experienced by the sedimentary deposits found by Curiosity. We propose that there were at least three major lake stands within Gale, each persisted >1000 years, and all occurred after Mount Sharp reached close to its current topographic f…
Influence of Venus topography on the zonal wind and UV albedo at cloud top level: The role of stationary gravity waves
Bertaux, Jean-Loup; Fedorova, A.; Lebonnois, S. +6 more
Based on the analysis of UV images (at 365 nm) of Venus cloud top (altitude 67 ± 2 km) collected with Venus Monitoring Camera on board Venus Express (VEX), it is found that the zonal wind speed south of the equator (from 5°S to 15°S) shows a conspicuous variation (from -101 to -83 m/s) with geographic longitude of Venus, correlated with the underl…
Recent shallow moonquake and impact-triggered boulder falls on the Moon: New insights from the Schrödinger basin
Head, James W.; Kiran Kumar, A. S.; Amitabh +8 more
Shallow moonquakes are thought to be of tectonic origin. However, the geologic structures responsible for these moonquakes are unknown. Here we report sites where moonquakes possibly occurred along young lobate scarps in the Schrödinger basin. Our analysis of Lunar Reconnaissance Orbiter and Chandrayaan-1 images revealed four lobate scarps in diff…
Geologic context of recurring slope lineae in Melas and Coprates Chasmata, Mars
McEwen, Alfred; Chojnacki, Matthew; Ojha, Lujendra +3 more
One of the major Mars discoveries of recent years is the existence of recurring slope lineae (RSL), which suggests that liquid water occurs on or near the surface of Mars today. These dark and narrow features emerge from steep, rocky exposures and incrementally grow, fade, and reform on a seasonal basis and are detected in images from the High Res…
Composition, seasonal change, and bathymetry of Ligeia Mare, Titan, derived from its microwave thermal emission
Lorenz, R. D.; Karatekin, O.; Janssen, M. A. +8 more
For the last decade, the passive radiometer incorporated in the Cassini RADAR has recorded the 2.2 cm wavelength thermal emission from Titan's seas. In this paper, we analyze the radiometry observations collected from February 2007 to January 2015 over one of these seas, Ligeia Mare, with the goal of providing constraints on its composition, bathy…
A cold-wet middle-latitude environment on Mars during the Hesperian-Amazonian transition: Evidence from northern Arabia valleys and paleolakes
Moore, Jeffrey M.; Wilson, Sharon A.; Howard, Alan D. +1 more
The growing inventory of post-Noachian fluvial valleys may represent a late, widespread episode of aqueous activity on Mars, contrary to the paradigm that fluvial activity largely ceased around the Noachian-Hesperian boundary. Fresh shallow valleys (FSVs) are widespread from ~30 to 45° in both hemispheres with a high concentration in northern Arab…
Setting constraints on the nature and origin of the two major hydrous sulfates on Mars: Monohydrated and polyhydrated sulfates
Liu, Yang; Wang, Alian; Jolliff, Bradley L. +1 more
Monohydrated Mg sulfate (MgSO4·H2O) and polyhydrated sulfate are the most common and abundant hydrous sulfates observed thus far on Mars. They are widely distributed and coexist in many locations. On the basis of results from two new sets of experiments, in combination with past experimental studies and the subsurface salt mi…