Publications
Filter Total Items: 959
Mars atmospheric surface interactions and the CO2 cycle Mars atmospheric surface interactions and the CO2 cycle
Mars' northern and southern seasonal polar caps are formed during their respective autumn and winter seasons both by condensation of atmospheric carbon dioxide (CO2) directly onto the surface, and through atmospheric precipitation in the form of CO2 snow. During the polar spring and summer, the seasonal ice sublimes, returning CO2 to the atmosphere. Roughly 25% of the atmosphere, which...
Authors
Timothy N. Titus, Anthony Colaprete
Constraints on mechanisms for the growth of gully alcoves in Gasa crater, Mars, from two-dimensional stability assessments of rock slopes Constraints on mechanisms for the growth of gully alcoves in Gasa crater, Mars, from two-dimensional stability assessments of rock slopes
The value of slope stability analyses for gaining insight into the geologic conditions that would facilitate the growth of gully alcoves on Mars is demonstrated in Gasa crater. Two-dimensional limit equilibrium methods are used in conjunction with high-resolution topography derived from stereo High Resolution Imaging Science Experiment (HiRISE) imagery. These analyses reveal three...
Authors
Chris H. Okubo, Livio L. Tornabene, Nina L. Lanza
Regional-scale stratigraphy of surface units in Tyrrhena and Iapygia Terrae, Mars: Insights into highland crustal evolution and alteration history Regional-scale stratigraphy of surface units in Tyrrhena and Iapygia Terrae, Mars: Insights into highland crustal evolution and alteration history
The compositional, thermophysical and geologic characteristics of surface units in Iapygia and Tyrrhena Terra (60°E–100°E, 0°–30°S) provide new insights into the compositional stratigraphy of the region. Intercrater plains are dominated by two surface units. The older unit (unit 1) is deficient in olivine and more degraded and likely consists of a mixture of impact, volcanic and...
Authors
A. Deanne Rogers, Robin L. Fergason
Thorium abundances of basalt ponds in South Pole-Aitken basin: Insights into the composition and evolution of the far side lunar mantle Thorium abundances of basalt ponds in South Pole-Aitken basin: Insights into the composition and evolution of the far side lunar mantle
Imbrian-aged basalt ponds, located on the floor of South Pole-Aitken (SPA) basin, are used to provide constraints on the composition and evolution of the far side lunar mantle. We use forward modeling of the Lunar Prospector Gamma Ray Spectrometer thorium data, to suggest that at least five different and distinct portions of the far side lunar mantle contain little or no thorium as of...
Authors
Justin Hagerty, D. J. Lawrence, B. R. Hawke
Bounce Rock-A shergottite-like basalt encountered at Meridiani Planum, Mars Bounce Rock-A shergottite-like basalt encountered at Meridiani Planum, Mars
The Opportunity rover of the Mars Exploration Rover mission encountered an isolated rock fragment with textural, mineralogical, and chemical properties similar to basaltic shergottites. This finding was confirmed by all rover instruments, and a comprehensive study of these results is reported here. Spectra from the miniature thermal emission spectrometer and the Panoramic Camera reveal a...
Authors
J. Zipfel, C. Schroder, B.L. Jolliff, Ralf Gellert, K. E. Herkenhoff, R. Rieder, R. Anderson, J.F. Bell, J. Bruckner, J.A. Crisp, P. R. Christensen, B.C. Clark, P.A. de Souza, G. Dreibus, C. D'uston, T. Economou, S.P. Gorevan, B.C. Hahn, G. Klingelhofer, T.J. McCoy, H.Y. McSween, D. W. Ming, R.V. Morris, D.S. Rodionov, S. W. Squyres, H. Wanke, S.P. Wright, M.B. Wyatt, A. S. Yen
Meteorites at Meridiani Planum provide evidence for significant amounts of surface and near-surface water on early Mars Meteorites at Meridiani Planum provide evidence for significant amounts of surface and near-surface water on early Mars
Six large iron meteorites have been discovered in the Meridiani Planum region of Mars by the Mars Exploration Rover Opportunity in a nearly 25 km-long traverse. Herein, we review and synthesize the available data to propose that the discovery and characteristics of the six meteorites could be explained as the result of their impact into a soft and wet surface, sometime during the...
Authors
Alberto G. Fairen, James M. Dohm, Victor R. Baker, Shane D. Thompson, William C. Mahaney, Kenneth E. Herkenhoff, J. Alexis P. Rodriguez, Alfonso F. Davila, Dirk Schulze-Makuch, M. Ramy El Maarry, Esther R. Uceda, Ricardo Amils, Hirdy Miyamoto, Kyeong J. Kim, Robert C. Anderson, Christopher P. McKay
Hyperspectral analysis of rocky surfaces on the Earth and other planetary systems: Chapter 27 Hyperspectral analysis of rocky surfaces on the Earth and other planetary systems: Chapter 27
This book is focused on studies of vegetation on Earth using hyperspectral remote sensing methods. However, it is appropriate to extend the application of these methods out to other rocky bodies in our Solar System for a variety of reasons. First, minerals, soils, and rocks form the substrate on which vegetation grows on Earth. Compositional analyses of these components with...
Authors
R. Greg Vaughan, Timothy N. Titus, Jeffery R Johnson, Justin Hagerty, Lisa R. Gaddis, Laurence A. Soderblom, Paul E. Geissler
Evidence for mechanical and chemical alteration of iron-nickel meteorites on Mars: Process insights for Meridiani Planum Evidence for mechanical and chemical alteration of iron-nickel meteorites on Mars: Process insights for Meridiani Planum
The weathering of meteorites found on Mars involves chemical and physical processes that can provide clues to climate conditions at the location of their discovery. Beginning on sol 1961, the Opportunity rover encountered three large iron meteorites within a few hundred meters of each other. In order of discovery, these rocks have been assigned the unofficial names Block Island, Shelter...
Authors
James W. Ashley, M.P. Golombek, P. R. Christensen, S. W. Squyres, T.J. McCoy, C. Schroder, I. Fleischer, J. R. Johnson, Kenneth E. Herkenhoff, T. J. Parker
The indication of Martian gully formation processes by slope-area analysis The indication of Martian gully formation processes by slope-area analysis
The formation process of recent gullies on Mars is currently under debate. This study aims to discriminate between the proposed formation processes - pure water flow, debris flow and dry mass wasting - through the application of geomorphological indices commonly used in terrestrial geomorphology. High-resolution digital elevation models (DEMs) of Earth and Mars were used to evaluate the...
Authors
Susan J. Conway, Matthew R. Balme, John B. Murray, Martin C. Towner, Chris Okubo, Peter M. Grindrod
Opportunity Mars Rover mission: Overview and selected results from Purgatory ripple to traverses to Endeavour crater Opportunity Mars Rover mission: Overview and selected results from Purgatory ripple to traverses to Endeavour crater
Opportunity has been traversing the Meridiani plains since 25 January 2004 (sol 1), acquiring numerous observations of the atmosphere, soils, and rocks. This paper provides an overview of key discoveries between sols 511 and 2300, complementing earlier papers covering results from the initial phases of the mission. Key new results include (1) atmospheric argon measurements that...
Authors
R. E. Arvidson, James W. Ashley, J.F. Bell, M. Chojnacki, J. Cohen, T.E. Economou, W. H. Farrand, Robin L. Fergason, I. Fleischer, Paul E. Geissler, Ralf Gellert, M.P. Golombek, J.P. Grotzinger, E.A. Guinness, R.M. Haberle, Kenneth E. Herkenhoff, J.A. Herman, K.D. Iagnemma, B.L. Jolliff, J. R. Johnson, G. Klingelhofer, A.H. Knoll, A.T. Knudson, R. Li, S. M. McLennan, D. W. Mittlefehldt, R.V. Morris, T. J. Parker, M.S. Rice, C. Schroder, Laurence A. Soderblom, S. W. Squyres, R.J. Sullivan, M.J. Wolff
Seasonal erosion and restoration of Mars' northern polar dunes Seasonal erosion and restoration of Mars' northern polar dunes
Despite radically different environmental conditions, terrestrial and martian dunes bear a strong resemblance, indicating that the basic processes of saltation and grainfall (sand avalanching down the dune slipface) operate on both worlds. Here, we show that martian dunes are subject to an additional modification process not found on Earth: springtime sublimation of Mars' CO 2 seasonal...
Authors
C.J. Hansen, M. Bourke, Nathan T. Bridges, Shane Byrne, C. Colon, S. Diniega, Colin M. Dundas, Kenneth E. Herkenhoff, A. McEwen, M. Mellon, Ganna Portyankina, N. Thomas
Extreme volcanism on Io: Latest insights at the end of Galileo era Extreme volcanism on Io: Latest insights at the end of Galileo era
Galileo has now completed 7 years exploring Jupiter. The spacecraft obtained breathtaking views of the four major satellites, and studied Jupiter's clouds and atmospheric composition, rings, small satellites, and magnetic field. It had five successful close flybys and many distant observations of Io. Scientists already knew from Voyager and Earth‐based astronomy that Io is by far the...
Authors
Jeffrey S. Kargel, Robert R. Carlson, Ashley G. Davies, Bruce Fegley, Alan R. Gillespie, Ronald Greeley, Robert G. Howells, Kandis Lea Jessup, Lucas Kamp, Laszlo P. Keszthelyi, Rosaly Lopes, Timothy MacIntyre, Franck Marchis, Alfred McEwen, Moses P. Milazzo, Jason Perry, Jani Radebaugh, Laura Schaefer, Nicholas Schmerr, William Smythe, John M. Spencer, David A. Williams, Ju Zhang, Mikhail Zolotov