Publications
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Martian mud volcanism: Terrestrial analogs and implications for formational scenarios Martian mud volcanism: Terrestrial analogs and implications for formational scenarios
The geology of Mars and the stratigraphic characteristics of its uppermost crust (mega-regolith) suggest that some of the pervasively-occurring pitted cones, mounds, and flows may have formed through processes akin to terrestrial mud volcanism. A comparison of terrestrial mud volcanism suggests that equivalent Martian processes likely required discrete sedimentary depocenters, volatile...
Authors
James A. Skinner, A. Mazzini
Observations of periglacial landforms in Utopia Planitia with the High Resolution Imaging Science Experiment (HiRISE) Observations of periglacial landforms in Utopia Planitia with the High Resolution Imaging Science Experiment (HiRISE)
The region of western Utopia Planitia (80-105 degreesE, 40-55 degrees N) displays several types of landforms similar to Earth periglacial features, including scallop-shaped depressions and networks of polygonal terrains. The scalloped depressions have been proposed to originate from thermokarstic processes such as sublimation and/or melting of near-surface ground ice. Using HiRISE...
Authors
A. Lefort, P.S. Russell, N. Thomas, A. S. McEwen, C. M. Dundas, Randolph L. Kirk
A prelanding assessment of the ice table depth and ground ice characteristics in Martian permafrost at the Phoenix landing site A prelanding assessment of the ice table depth and ground ice characteristics in Martian permafrost at the Phoenix landing site
We review multiple estimates of the ice table depth at potential Phoenix landing sites and consider the possible state and distribution of subsurface ice. A two-layer model of ice-rich material overlain by ice-free material is consistent with both the observational and theoretical lines of evidence. Results indicate ground ice to be shallow and ubiquitous, 2-6 cm below the surface...
Authors
Michael T. Mellon, William V. Boynton, William C. Feldman, Raymond E. Arvidson, Timothy N. Titus, Joshua L. Bandfield, Nathaniel E. Putzig, H.G. Sizemore
Photometric changes on Saturn's Titan: Evidence for active cryovolcanism Photometric changes on Saturn's Titan: Evidence for active cryovolcanism
We report infrared spectrophotometric variability on the surface of Saturn's moon Titan detected in images returned by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Saturn Orbiter. The changes were observed at 7°S, 138°W and occurred between October 27, 2005 and January 15, 2006. After that date the surface was unchanged until the most recent observation, March...
Authors
Robert M. Nelson, Lucas W. Kamp, Rosaly Lopes, Dennis L. Matson, Randolph L. Kirk, Bruce W. Hapke, Stephen D. Wall, Mark D. Boryta, Frank E. Leader, William D. Smythe, Karl L. Mitchell, Kevin H. Baines, Ralf Jaumann, Christophe Sotin, Roger N. Clark, Dale P. Cruikshank, Pierre Drossart, Jonathan I. Lunine, Michel Combes, Giancarlo Bellucci, Jean-Pierre Bibring, Fabrizio Capaccioni, Pricilla Cerroni, Angioletta Coradini, Vittorio Formisano, Gianrico Filacchione, Yves Langevin, Thomas B. McCord, Vito Mennella, Philip D. Nicholson, Bruno Sicardy, Patrick G.J. Irwin, John C. Pearl
Dielectric properties of lava flows west of Ascraeus Mons, Mars Dielectric properties of lava flows west of Ascraeus Mons, Mars
The SHARAD instrument on the Mars Reconnaissance Orbiter detects subsurface interfaces beneath lava flow fields northwest of Ascraeus Mons. The interfaces occur in two locations; a northern flow that originates south of Alba Patera, and a southern flow that originates at the rift zone between Ascraeus and Pavonis Montes. The northern flow has permittivity values, estimated from the time...
Authors
Lynn M. Carter, Bruce A. Campbell, John W. Holt, Roger J. Phillips, Nathaniel E. Putzig, Stefania Mattei, Roberto Seu, Chris H. Okubo, Anthony F. Egan
Overview of the magnetic properties experiments on the Mars Exploration Rovers Overview of the magnetic properties experiments on the Mars Exploration Rovers
The Mars Exploration Rovers have accumulated airborne dust on different types of permanent magnets. Images of these magnets document the dynamics of dust capture and removal over time. The strongly magnetic subset of airborne dust appears dark brown to black in Panoramic Camera (Pancam) images, while the weakly magnetic one is bright red. Images returned by the Microscopic Imager reveal...
Authors
M.B. Madsen, W. Goetz, P. Bertelsen, C.S. Binau, F. Folkmann, H.P. Gunnlaugsson, J.I. Hjollum, S.F. Hviid, J. Jensen, K.M. Kinch, K. Leer, D.E. Madsen, J. Merrison, M. Olsen, H.M. Arneson, J.F. Bell, Ralf Gellert, Kenneth E. Herkenhoff, J. R. Johnson, M. J. Johnson, G. Klingelhofer, E. McCartney, D. W. Ming, R.V. Morris, J.B. Proton, D. Rodionov, M. Sims, S. W. Squyres, T. Wdowiak, A. S. Yen
Analysis of a cryolava flow-like feature on Titan Analysis of a cryolava flow-like feature on Titan
This paper reports on the analysis of the highest spatial resolution hyperspectral images acquired by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft during its prime mission. A bright area matches a flow-like feature coming out of a caldera-like feature observed in Synthetic Aperture Radar (SAR) data recorded by the Cassini radar experiment [Lopes et...
Authors
L. Le Corre, S. Le Mouelic, Christophe Sotin, J. #NAME? Combe, S. Rodriguez, J. W. Barnes, R. H. Brown, B. J. Buratti, R. Jaumann, J. Soderblom, L.A. Soderblom, R. Clark, K. H. Baines, P. D. Nicholson
Shallow radar (SHARAD) sounding observations of the Medusae Fossae Formation, Mars Shallow radar (SHARAD) sounding observations of the Medusae Fossae Formation, Mars
The SHARAD (shallow radar) sounding radar on the Mars Reconnaissance Orbiter detects subsurface reflections in the eastern and western parts of the Medusae Fossae Formation (MFF). The radar waves penetrate up to 580 m of the MFF and detect clear subsurface interfaces in two locations: west MFF between 150 and 155° E and east MFF between 209 and 213° E. Analysis of SHARAD radargrams...
Authors
Lynn M. Carter, Bruce A. Campbell, Thomas R. Watters, Roger J. Phillips, Nathaniel E. Putzig, Ali Safaeinili, Jeffrey J. Plaut, Chris Okubo, Anthony F. Egan, Roberto Seu, Daniela Biccari, Roberto Orosei
The discovery of columnar jointing on Mars The discovery of columnar jointing on Mars
We report on the discovery of columnar jointing in Marte Valles, Mars. These columnar lavas were discovered in the wall of a pristine, 16-km-diameter impact crater and exhibit the features of terrestrial columnar basalts. There are discontinuous outcrops along the entire crater wall, suggesting that the columnar rocks covered a surface area of at least 200 km2, assuming that the rocks...
Authors
Moses P. Milazzo, Laszlo P. Keszthelyi, Windy L. Jaeger, Mark R. Rosiek, Sarah Mattson, C. Verba, Ross A. Beyer, Paul E. Geissler, Alfred S. McEwen
Deformation band clusters on Mars and implications for subsurface fluid flow Deformation band clusters on Mars and implications for subsurface fluid flow
High-resolution imagery reveals unprecedented lines of evidence for the presence of deformation band clusters in layered sedimentary deposits in the equatorial region of Mars. Deformation bands are a class of geologic structural discontinuity that is a precursor to faults in clastic rocks and soils. Clusters of deformation bands, consisting of many hundreds of individual subparallel...
Authors
Chris Okubo, Richard A. Schultz, Marjorie A. Chan, Goro Komatsu
Size and shape of Saturn's moon Titan Size and shape of Saturn's moon Titan
Cassini observations show that Saturn’s moon Titan is slightly oblate. A fourth-order spherical harmonic expansion yields north polar, south polar, and mean equatorial radii of 2574.32 ± 0.05 kilometers (km), 2574.36 ± 0.03 km, and 2574.91 ± 0.11 km, respectively; its mean radius is 2574.73 ± 0.09 km. Titan’s shape approximates a hydrostatic, synchronously rotating triaxial ellipsoid but...
Authors
Howard A. Zebker, Bryan Stiles, Scott Hensley, Ralph Lorenz, Randolph L. Kirk, Jonathan Lunine
Determining Titan surface topography from Cassini SAR data Determining Titan surface topography from Cassini SAR data
A technique, referred to as SARTopo, has been developed for obtaining surface height estimates with 10 km horizontal resolution and 75 m vertical resolution of the surface of Titan along each Cassini Synthetic Aperture Radar (SAR) swath. We describe the technique and present maps of the co-located data sets. A global map and regional maps of Xanadu and the northern hemisphere hydrocarbon...
Authors
Bryan W. Stiles, Scott Hensley, Yonggyu Gim, David M. Bates, Randolph L. Kirk, Alex Hayes, Jani Radebaugh, Ralph D. Lorenz, Karl L. Mitchell, Philip S. Callahan, Howard Zebker, William T.K. Johnson, Stephen D. Wall, Jonathan I. Lunine, Charles A. Wood, Michael Janssen, Frederic Pelletier, Richard D. West, Chandini Veeramacheneni