Assessment of Mars Science and Mission Priorities (2003) / Chapter Skim
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5. Surface Processes and Geomorphology
5. Surface Processes and Geomorphology
Pages 34-47
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From page 34... ...
Fluvial features range in size from the giant martian outflow channels to valley networks to recently identified small, young channels.2 3 Morphologic features indicative of standing bodies of water similarly range from putative shoreline features in the northern hemisphere, perhaps resulting from an ocean,4 to deltaic and intracrater sediments, to finely layered bedding. It is important to note, however, that some of these features are equivocal as evidence for specific processes involving water, or even that water was involved in their formation.
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From page 35... ...
Schneeberger ("Coastal Geomorphology of the Martian Northern Plains," Journal of Geophysical Research 98: 11061-11078, 1993, copyright 1993 by the American Geophysical Union) for a north polar ocean, drawn on a Mars Orbiter Laser Altimeter representation of topography for the northern hemisphere; "C1" refers to Contact 1 and "C2" to Contact 2 (after J.W.
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From page 36... ...
Results from the MGS mission consistent with a northern ocean are that the northern plains inside of Shoreline 2 are extremely smooth, and that the elevation of Shoreline 2 approximates an equipotential surface.~3 However, morphologic features diagnostic of shoreline processes are not immediately evident in the high-resolution Mars Orbiter Camera (MOC) images,~4 though this may be because the observations are not at the relevant scale of the features; additionally, some of the proposed shoreline features identified with Viking images may be tectonic in origin.~5 The origin of the vast, smooth northern plains is nevertheless associated with the catastrophic outflow channels.
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From page 37... ...
Sediments Sediments deposited in standing bodies of water are high-priority sites for the preservation of fossils and biosignatures.27 Many of the valley networks terminate in craters, while the outflow channels primarily debauched to the northern plains. Many morphologic features in craters and the northern plains have been interpreted to be either directly (e.g., deltas)
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From page 38... ...
exhibit rough, grooved surfaces, indicating that the dunes are indurated and are undergoing erosion (MOC Image M0003222~. Courtesy of NASA/JPL/Malin Space Science Systems.
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From page 39... ...
Our understanding of magma chemistry and absolute chronology is, however, primitive, and it is not yet clear whether the range in volcanic styles represents changes in source regions, changes in near-surface environments, or atmospheric evolution. In addition, there is extensive evidence for magma-volatile interactions in the observed volcanic landforms.3940 Topographic and imaging data acquired during the MGS mission, now being assimilated into the prior knowledge base, provide evidence for very ancient as well as very young (<10 million years)
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From page 40... ...
Based on the Sun direction and shadow length, this dust devil is approximately 1 km in height. A faint track caused by its passage is visible on the surface.
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From page 41... ...
is clearly oxidized, but the timing, rates, and processes of this oxidation are poorly understood. The chemical compositions of the oxidized mobile materials measured directly by the Viking and Pathfinder missions were remarkably similar, despite the
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From page 42... ...
The general composition of the soils can be explained by hydrolytic weathering of basalt with a significant addition of S and C1 through the atmospheric deposition of volcanic aerosols.42 Remotely sensed data provide additional constraints on the surface mineralogy. The general visible/near-infrared spectral properties are well modeled by palagonite, a poorly crystallized product of low-temperature basalt alteration.
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From page 43... ...
Measurement of the spectral properties of the surface at moderate and high spatial resolution, to determine mineralogy; and 3. Landed science investigations to acquire detailed measurements of surface properties, and surface processes, and for the selection of samples for return to Earth.
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From page 44... ...
With a successful completion of the orbital observations through the MRO mission, the global reconnaissance mapping of the Mars surface with remotely sensed data will be largely complete. The only major observation that will not be covered is synthetic aperture radar imaging with multiple polarizations and frequencies.
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From page 45... ...
Landed science investigations, carefully targeted within sites for which the full suite of remotely sensed data are available, will allow extrapolation of detailed field investigations to larger scales. This combination of results will address many, but not all, of the important science goals relevant to the chemical and mineralogical signatures of geomorphic processes and surface evolution.
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From page 46... ...
Ruff, and M.D. Smith, "Detection of Crystalline Hematite Mineralization on Mars by the Thermal Emission Spectrometer: Evidence for Near-surface Water," Journal of Geophysical Research 105: 9623-9642, 2000.
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From page 47... ...
Ruff, and M.D. Smith, "Detection of Crystalline Hematite Mineralization on Mars by the Thermal Emission Spectrometer: Evidence for Near-Surface Water," Journal of Geophysical Research 105: 9623-9642, 2000.
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