Geology of the Southern Utopia Planitia Highland-Lowland Boundary Plain: First Year Results and Second Year Plan

NASA Technical Reports Server (NTRS)

Skinner, J. A., Jr.; Tanaka, K. L.; Hare, T. M.

2008-01-01

The southern Utopia highland-lowland boundary (HLB) extends >1500 km westward from northern Nepenthes Mensae to the topographic saddle that separates Isidis and Utopia Planitiae. It contains bench-like platforms that contain depressions, pitted cones (some organized into arcuate chains and thumbprint terrain), isolated domes, lineated depressions, buried circular depressions, ring fractures, polygonal fractures, and other locally- to regionally-dispersed landforms [1]. The objective of our mapping project is to clarify the geologic evolution of the southern Utopia Planitia HLB by identifying the geologic, structural, and stratigraphic relationships of surface materials in MTMs 10237, 15237, 20237, 10242, 15242, 20242, 10247, 15247, and 20247.

Cracky Mars

NASA Technical Reports Server (NTRS)

2006-01-01

21 September 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows cracked, layered plains-forming material in the western part of Utopia Planitia, Mars. Investigators have speculated that ice might be -- or might once have been -- present in the ground, and changes in temperature and the amount of ice over time may have led to the formation of these cracks. But no one is certain just how these features formed.

Location near: 45.0oN, 276.1oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Spring

Mola Topography Supports Drape-Folding Models for Polygonal Terrain of Utopia Planitia, Mars

NASA Technical Reports Server (NTRS)

McGill, George E.; Buczkowski, D. L.

2002-01-01

One of the most important questions we ask about Mars is whether or not there have ever been large bodies of standing water on the surface. The polygonal terrains of Utopia and Acidalia Planitiae are located in the lowest parts of the northern lowlands, the most logical places for water to pond and sediments to accumulate. Showing that polygonal terrain is sedimentary in origin would represent strong evidence in favor of a northern ocean. A number of hypotheses for the origin of the giant martian polygons have been proposed, from the cooling of lava to frost wedging to the desiccation of wet sediments, but Pechman showed that none of these familiar processes could be scaled up to martian dimensions. Two models for polygon origin attempt to explain the scale of the martian polygons by postulating drape folding of a cover material, either sedimentary or volcanic, over an uneven, buried surface. The drape folding would produce bending stresses in the surface layers that increase the probability of Fracturing over drape anticlines and suppress the probability of fracturing over drape synclines. However, both models require an additional source of extensional strain to produce the total strain needed to produce the observed troughs.

The mosaics of Mars: As seen by the Viking Lander cameras

NASA Technical Reports Server (NTRS)

Levinthal, E. C.; Jones, K. L.

1980-01-01

The mosaics and derivative products produced from many individual high resolution images acquired by the Viking Lander Camera Systems are described: A morning and afternoon mosaic for both cameras at the Lander 1 Chryse Planitia site, and a morning, noon, and afternoon camera pair at Utopia Planitia, the Lander 11 site. The derived products include special geometric projections of the mosaic data sets, polar stereographic (donut), stereoscopic, and orthographic. Contour maps and vertical profiles of the topography were overlaid on the mosaics from which they were derived. Sets of stereo pairs were extracted and enlarged from stereoscopic projections of the mosaics.

Pingos on Earth and Mars

USGS Publications Warehouse

Burr, D.M.; Tanaka, K.L.; Yoshikawa, K.

2009-01-01

Pingos are massive ice-cored mounds that develop through pressurized groundwater flow mechanisms. Pingos and their collapsed forms are found in periglacial and paleoperiglacial terrains on Earth, and have been hypothesized for a wide variety of locations on Mars. This literature review of pingos on Earth and Mars first summarizes the morphology of terrestrial pingos and their geologic contexts. That information is then used to asses hypothesized pingos on Mars. Pingo-like forms (PLFs) in Utopia Planitia are the most viable candidates for pingos or collapsed pingos. Other PLFs hypothesized in the literature to be pingos may be better explained with other mechanisms than those associated with terrestrial-style pingos. ?? 2008 Elsevier Ltd.

Viking Lander Mosaics of Mars

NASA Technical Reports Server (NTRS)

Morris, E. C.

1985-01-01

The Viking Lander 1 and 2 cameras acquired many high-resolution pictures of the Chryse Planitia and Utopia Planitia landing sites. Based on computer-processed data of a selected number of these pictures, eight high-resolution mosaics were published by the U.S. Geological Survey as part of the Atlas of Mars, Miscellaneous Investigation Series. The mosaics are composites of the best picture elements (pixels) of all the Lander pictures used. Each complete mosaic extends 342.5 deg in azimuth, from approximately 5 deg above the horizon to 60 deg below, and incorporates approximately 15 million pixels. Each mosaic is shown in a set of five sheets. One sheet contains the full panorama from one camera taken in either morning or evening. The other four sheets show sectors of the panorama at an enlarged scale; when joined together they make a panorama approximately 2' X 9'.

Concentric crater fill on Mars - An aeolian alternative to ice-rich mass wasting

NASA Technical Reports Server (NTRS)

Zimbelman, J. R.; Clifford, S. M.; Williams, S. H.

1989-01-01

Concentric crater fill, a distinctive martian landform represented by a concentric pattern of surface undulations confined within a crater rim, has been interpreted as an example of ice-enhanced regolith creep at midlatitudes (e.g., Squyres and Carr, 1986). Theoretical constraints on the stability and mobility of ground ice limit the applicability of an ice-rich soil in effectively mobilizing downslope movement at latitudes poleward of + or - 30 deg, where concentric crater fill is observed. High-resolution images of concentric crater fill material in the Utopia Planitia region (45 deg N, 271 deg W) show it to be an eroded, multiple-layer deposit. Layering should not be preserved if the crater fill material moved by slow deformation throughout its thickness, as envisioned in the ice-enhanced creep model. Multiple layers are also exposed in the plains material surrounding the craters, indicating a recurrent depositional process that was at least regional in extent. Mantling layers are observed in high-resolution images of many other locations around Mars, suggesting that deposition occurred on a global scale and was not limited to the Utopia Planitia region. It is suggested that an aeolian interpretation for the origin and modification of concentric crater fill material is most consistent with morphologic and theoretical constraints.

Geology of the Terra Cimmeria-Utopia Planitia Highland Lowland Transitional Zone: Final Technical Approach and Scientific Results

NASA Technical Reports Server (NTRS)

Skinner, J. A., Jr.; Tanaka, K. L.

2010-01-01

The southern Utopia highland-lowland transitional zone extends from northern Terra Cimmeria to southern Utopia Planitia and contains broad, bench-like platforms with depressions, pitted cones, tholi, and lobate flows. The locally occurring geologic units and landforms contrast other transitional regions and record a spatially partitioned geologic history. We systematically delineated and described the geologic units and landforms of the southern Utopia-Cimmeria highland-lowland transitional zone for the production of a 1:1,000,000-scale geologic map (MTMs 10237, 15237, 20237, 10242, 15242, 20242, 10247, 15247, and 20247). Herein, we present technical and scientific results of this mapping project.

Mars Data Analysis Program

NASA Technical Reports Server (NTRS)

McGill, George E.

2004-01-01

Grant NAGS12158 addressed a major NASA objective concerning the possibility of a palm ocean or large lake in the northern lowlands of Mars. Our overall approach for this study was an analysis of the graben-bounded giant polygons of Utopia Planitia, but specifically those grabens that define circles rather than open polygons. These circular grabens overlie buried impact craters, and the grabens form because of differential compaction of the overlying material over crater rims and floors. Several years ago, I predicted that the graben circles would bound depressions, and that the depths of these depressions would scale with the diameters of the graben circles. These predictions have been verified by earlier analysis. During this one-year grant (with one-year no-cost extension) we greatly increased the sample size and validated the earlier research robustly. What remained unexplained was why most of the graben circles in Utopia Planitia were double. A new model, involving volumetric compaction rather than simply 2-D compaction, satisfactorily explains the double rings and also provides a measure of relative thickness of the cover material burying the craters as a function of radial distance from the center of the Utopia Basin. Only two materials are likely candidates for the compacting cover material: volcanic ash, or wet sediment. The water in the wet sediment is largely responsible for the volumetric compaction; dry ash will compact vertically but experiences very limited lateral shrinkage. Thus the depressions within the circular grabens and the model explaining the double rings strongly favor wet sediment and thus provide evidence in favor of a past body of standing water in the northern lowlands. Publications supported entirely or in part by this grant are listed below.

Geology of the Southern Utopia Planitia Highland-Lowland Boundary Plain: Second Year Results and Third Year Plan

NASA Technical Reports Server (NTRS)

Skinner, J. A., Jr.; Tanaka, K. L.; Hare, T. M.

2009-01-01

The southern Utopia highland-lowland boundary (HLB) extends >1500 km westward from Hyblaeus Dorsa to the topographic saddle that separates Isidis and Utopia Planitiae. It contains bench-like platforms that contain depressions, pitted cones (some organized into arcuate chains and thumb-print terrain), isolated domes, buried circular depressions, ring fractures, polygonal fractures, and other locally- to regionally-dispersed landforms [1-2]. The objective of this map project is to clarify the geologic evolution of the southern Utopia Planitia HLB by identifying the geologic, structural, and stratigraphic relationships of surface materials in MTMs 10237, 15237, 20237, 10242, 15242, 20242, 10247, 15247, and 20247. The project was originally awarded in April, 2007 and is in its final year of support. Mapping is on-schedule and formal map submission will occur by December, 2009, with finalization anticipated by April, 2010. Herein, we (1) review specifics regarding mapping data and methods, (2) present nomenclature requests that we feel will assist with unit descriptions, (3) describe Year 2 mapping and science accomplishments, and (4) outline Year 3 technical and managerial approaches for finalizing the geologic map.

Use of spacecraft data to derive regions on Mars where liquid water would be stable

PubMed Central

Lobitz, Brad; Wood, Byron L.; Averner, Maurice M.; McKay, Christopher P.

2001-01-01

Combining Viking pressure and temperature data with Mars Orbital Laser Altimeter topography data, we have computed the fraction of the martian year during which pressure and temperature allow for liquid water to be stable on the martian surface. We find that liquid water would be stable within the Hellas and Argyre basin and over the northern lowlands equatorward of about 40°. The location with the maximum period of stable conditions for liquid water is in the southeastern portion of Utopia Planitia, where 34% of the year liquid water would be stable if it were present. Locations of stability appear to correlate with the distribution of valley networks. PMID:11226204

Use of Spacecraft Data to Drive Regions on Mars where Liquid Water would be Stable

NASA Technical Reports Server (NTRS)

Lobitz, Brad; Wood, Byron L.; Averner, Maurice M.; McKay, Christopher P.; MacElroy, Robert D.

2001-01-01

Combining Viking pressure and temperature data with Mars Orbital Laser Altimeter (MOLA) topography data we have computed the fraction of the martian year during which pressure and temperature allow for liquid water to be stable on the martian surface. We find that liquid water would be stable within the Hellas and Argyre basin and over the northern lowlands equatorward of about 40 degrees. The location with the maximum period of stable conditions for liquid water is in the southeastern portion of Utopia Planitia where 34% of the year liquid water would be stable if it was present. Locations of stability appear to correlate with the distribution of valley networks.

Periglacial complexes in Utopia Planitia: rimless, tiered depressions, (clastically) sorted and unsorted polygonised terrain and an ice-rich mantle

NASA Astrophysics Data System (ADS)

Soare, Richard; Conway, Susan; Gallagher, Colman; Dohm, James; Clifford, Stephen M.; Williams, Jean-pierre

2016-10-01

We report the spatial and possible genetic-relationship at the mid-latitudes of Utopia Planitia (45-500N 115-1200E), Mars, of: (a) metre to decametre deep, rimless, tiered depressions; terrain that exhibits (b) (clastically) sorted and (c) unsorted (small-sized) polygons; and, (d) a very youthful, ice-rich mantle. We show that these individual landscape features are separated stratigraphically, this being presented to the Mars community for the first time, and suggest that the stratigraphical separation of these features could be the result of boundary conditions and formation processes that have varied much more widely than has been thought hitherto. In cold-climate and non-glacial regions such as the Yamal Peninsula of eastern Russia and the Tuktoyaktuk Coastlands of northern Canada, landscape assemblages comprised of similar features are referenced as "ice complexes" and are indicative of periglacialism on two fronts: first, the presence of "ice-rich" permafrost or permafrost comprised of "excess ice", i.e. "permafrost" whose pore space is exceeded by the "water ice" within that body of sediment; and, second, antecedently or currently active freeze-thaw cycling, minimally, to the full depth of the "ice-complex" depressions. In the Dry Valleys of the Antarctic, where the atmospheric aridity and cold-temperatures approach those of Mars, ice-vapour diffusion and adsorption cycles are cited as the means by which the near-surface, permafrost, i.e. ≤1m deep, has become ice-cemented. However, the metre to decametre depths of the "ice-complex" depressions on Earth and the morphologically-similar ones on Mars lie beyond the vertical reach of the Antarctic diffusion and adsorption cycles, both empirically and theoretically. By deduction, this points to the freeze-thaw cycling of water to depth, fostered either by exogenic or endogenic means, perhaps playing a more important role in the formation of the possible Martian "ice complexes" than might be expected were expectations based solely on the current cold-climate "Antarctic-like" paradigm.

Northwestern Tharsis Latent Outflow Activity Mars

NASA Technical Reports Server (NTRS)

Dohm, J. M.; Anderson, R. C.; Baker, V. R.; Ferris, J. C.; Hare, T. M.; Strom, R. G.; Rudd, L.; Rice, J. W., Jr.; Scott, D. H.

2000-01-01

Previously defined outflow channels, which are indicated by relict landforms similar to those observed on Earth, signify ancient catastrophic flood events on Mars. These conspicuous geomorphic features are some of the most remarkable yet profound discoveries made by geologists to date. These outflow channels, which debouched tremendous volumes of water into topographic lows such as Chryse, Utopia, Elysium, and Hellas Planitiae, may represent the beginning of warmer and wetter climatic periods unlike the present-day cold and dry Mars. In addition to the previously identified outflow channels, observations permitted by the newly acquired Mars Orbiter Laser Altimeter (MOLA) data have revealed a system of gigantic valleys, referred to as the northwestern slope valleys (NSV), that are located to the northwest of a huge shield volcano, Arsia Mons, western hemisphere of Mars. These features generally correspond spatially to gravity lows similar to the easternmost, circum-Chryse outflow channel systems. Geologic investigations of the Tharsis region suggest that the large valley system pre-dates the construction of Arsia Mons and its extensive associated lava flows of mainly Late Hesperian and Amazonian age and coincides stratigraphically with the early development of the circum-Chryse outflow channel systems that debouch into Chryse Planitia. This newly identified system, the NSV, potentially signifies the largest flood event(s) ever recorded for the solar system. Additional information is contained in original extended abstract.

Small-scale martian polygonal terrain: Implications for liquid surface water

USGS Publications Warehouse

Seibert, N.M.; Kargel, J.S.

2001-01-01

Images from the Mars Orbiter Camera (MOC) through August 1999 were analyzed for the global distribution of small-scale polygonal terrain not clearly resolved in Viking Orbiter imagery. With very few exceptions, small-scale polygonal terrain occurs at middle to high latitudes of the northern and southern hemisphere in Hesperian-age geologic units. The largest concentration of this terrain occurs in the Utopia basin in close association with scalloped depressions (interpreted as thermokarst) and appears to represent an Amazonia event. The morphology and occurence of small polygonal terrain suggest they are either mud desiccation cracks or ice-wedge polygons. Because the small-scale polygons in Utopia and Argyre Planitiae are associated with other cold-climate permafrost or glacial features, an ice-wedge model is preferred for these areas. Both cracking mechanisms work most effectively in water- or ice-rich finegrained material and may imply the seasonal or episodic existence of liquid water at the surface.

The search for organic substances and inorganic volatile compounds in the surface of Mars

NASA Technical Reports Server (NTRS)

Biemann, K.; Oro, J.; Toulmin, P., III; Orgel, L. E.; Nier, A. O.; Anderson, D. M.; Flory, D.; Diaz, A. V.; Rushneck, D. R.; Simmonds, P. G.

1977-01-01

A total of four Martian samples, one surface and one subsurface sample at each of the two Viking landing sites, Chryse Planitia and Utopia Planitia, have been analyzed for organic compounds by a gas chromatograph-mass spectrometer. In none of these experiments could organic material of Martian origin be detected at detection limits generally of the order of parts per billion and for a few substances closer to parts per million. The evolution of water and carbon dioxide, but not of other inorganic gases, was observed upon heating the sample to temperatures of up to 500 C. The absence of organic compounds seems to preclude their production on the planet at rates that exceed the rate of their destruction. It also makes it unlikely that living systems that behave in a manner similar to terrestrial biota exist, at least at the two Viking landing sites.

Clouds Near Mie Crater

NASA Image and Video Library

2003-12-13

Mie Crater, a large basin formed by asteroid or comet impact in Utopia Planitia, lies at the center of this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) red wide angle image. The crater is approximately 104 km (65 mi) across. To the east and southeast (toward the lower right) of Mie, in this 5 December 2003 view, are clouds of dust and water ice kicked up by local dust storm activity. It is mid-winter in the northern hemisphere of Mars, a time when passing storms are common on the northern plains of the red planet. Sunlight illuminates this image from the lower left; Mie Crater is located at 48.5°N, 220.3°W. Viking 2 landed west/southwest of Mie Crater, off the left edge of this image, in September 1976. http://photojournal.jpl.nasa.gov/catalog/PIA04930

Abstracts of the Annual Meeting of Planetary Geologic Mappers, Flagstaff, AZ, 2008

NASA Technical Reports Server (NTRS)

Bleamaster, Leslie F., III (Editor); Tanaka, Kenneth L. (Editor); Kelley, Michael S. (Editor)

2008-01-01

Topics discussed include: Merging of the USGS Atlas of Mercury 1:5,000,000 Geologic Series; Geologic Mapping of the V-36 Thetis Regio Quadrangle: 2008 Progress Report; Structural Maps of the V-17 Beta Regio Quadrangle, Venus; Geologic Mapping of Isabella Quadrangle (V-50) and Helen Planitia, Venus; Renewed Mapping of the Nepthys Mons Quadrangle (V-54), Venus; Mapping the Sedna-Lavinia Region of Venus; Geologic Mapping of the Guinevere Planitia Quadrangle of Venus; Geological Mapping of Fortuna Tessera (V-2): Venus and Earth's Archean Process Comparisons; Geological Mapping of the North Polar Region of Venus (V-1 Snegurochka Planitia): Significant Problems and Comparisons to the Earth's Archean; Venus Quadrangle Geological Mapping: Use of Geoscience Data Visualization Systems in Mapping and Training; Geologic Map of the V-1 Snegurochka Planitia Quadrangle: Progress Report; The Fredegonde (V-57) Quadrangle, Venus: Characterization of the Venus Midlands; Formation and Evolution of Lakshmi Planum (V-7), Venus: Assessment of Models using Observations from Geological Mapping; Geologic Map of the Meskhent Tessera Quadrangle (V-3), Venus: Evidence for Early Formation and Preservation of Regional Topography; Geological Mapping of the Lada Terra (V-56) Quadrangle, Venus: A Progress Report; Geology of the Lachesis Tessera Quadrangle (V-18), Venus; Geologic Mapping of the Juno Chasma Quadrangle, Venus: Establishing the Relation Between Rifting and Volcanism; Geologic Mapping of V-19, V-28, and V-53; Lunar Geologic Mapping Program: 2008 Update; Geologic Mapping of the Marius Quadrangle, the Moon; Geologic Mapping along the Arabia Terra Dichotomy Boundary: Mawrth Vallis and Nili Fossae, Mars: Introductory Report; New Geologic Map of the Argyre Region of Mars; Geologic Evolution of the Martian Highlands: MTMs -20002, -20007, -25002, and -25007; Mapping Hesperia Planum, Mars; Geologic Mapping of the Meridiani Region, Mars; Geology of Holden Crater and the Holden and Ladon Multi-Ring Impact Basins, Margaritifer Terra, Mars; Geologic Mapping of Athabasca Valles; Geologic Mapping of MTM -30247, -35247 and -40247 Quadrangles, Reull Vallis Region of Mars; Geologic Mapping of the Martian Impact Crater Tooting; Geology of the Southern Utopia Planitia Highland-Lowland Boundary Plain: First Year Results and Second Year Plan; Mars Global Geologic Mapping: Amazonian Results; Recent Geologic Mapping Results for the Polar Regions of Mars; Geologic Mapping of the Medusae Fossae Formation on Mars (MC-8 SE and MC-23 NW) and the Northern Lowlands of Venus (V-16 and V-15); Geologic Mapping of the Zal, Hi'iaka, and Shamshu Regions of Io; Global Geologic Map of Europa; Material Units, Structures/Landforms, and Stratigraphy for the Global Geologic Map of Ganymede (1:15M); and Global Geologic Mapping of Io: Preliminary Results.

Sub-ice volcanoes and ancient oceans/lakes: A Martian challenge

USGS Publications Warehouse

Chapman, M.G.

2003-01-01

New instruments on board the Mars Global Surveyor (MGS) spacecraft began providing accurate, high-resolution image and topography data from the planet in 1997. Though data from the Mars Orbiter Laser Altimeter (MOLA) are consistent with hypotheses that suggest large standing bodies of water/ice in the northern lowlands in the planet's past history, Mars Orbiter Camera (MOC) images acquired to test these hypotheses have provided negative or ambiguous results. In the absence of classic coastal features to test the paleo-ocean hypothesis, other indicators need to be examined. Tuyas and hyaloclastic ridges are subice volcanoes of unique appearance that form in ponded water conditions on Earth. Features with similar characteristics occur on Mars. MOLA analyses of these Martian features provide estimates of the height of putative ice/water columns at the edge of the Utopia Planitia basin and within Ophir Chasma of Valles Marineris, and support the hypotheses of a northern ocean on Mars. ?? 2003 Elsevier Science B.V. All rights reserved.

Abstracts of the Annual Meeting of Planetary Geologic Mappers, San Antonio, TX, 2009

NASA Technical Reports Server (NTRS)

Bleamaster, Leslie F., III (Editor); Tanaka, Kenneth L.; Kelley, Michael S.

2009-01-01

Topics covered include: Geologic Mapping of the Beta-Atla-Themis (BAT) Region of Venus: A Progress Report; Geologic Map of the Snegurochka Planitia Quadrangle (V-1): Implications for Tectonic and Volcanic History of the North Polar Region of Venus; Preliminary Geological Map of the Fortuna Tessera (V-2) Quadrangle, Venus; Geological Map of the Fredegonde (V-57) Quadrangle, Venus; Geological Mapping of the Lada Terra (V-56) Quadrangle, Venus; Geologic Mapping of V-19; Lunar Geologic Mapping: A Preliminary Map of a Portion of the LQ-10 ("Marius") Quadrangle; Geologic Mapping of the Lunar South Pole, Quadrangle LQ-30: Volcanic History and Stratigraphy of Schr dinger Basin; Geologic Mapping along the Arabia Terra Dichotomy Boundary: Mawrth Vallis and Nili Fossae, Mars; Geologic Mapping Investigations of the Northwest Rim of Hellas Basin, Mars; Geologic Mapping of the Meridiani Region of Mars; Geology of a Portion of the Martian Highlands: MTMs -20002, -20007, -25002 and -25007; Geologic Mapping of Holden Crater and the Uzboi-Ladon-Morava Outflow System; Mapping Tyrrhena Patera and Hesperia Planum, Mars; Geologic Mapping of Athabaca Valles; Geologic Mapping of MTM -30247, -35247 and -40247 Quadrangles, Reull Vallis Region, Mars Topography of the Martian Impact Crater Tooting; Mars Structural and Stratigraphic Mapping along the Coprates Rise; Geology of Libya Montes and the Interbasin Plains of Northern Tyrrhena Terra, Mars: Project Introduction and First Year Work Plan; Geology of the Southern Utopia Planitia Highland-Lowland Boundary Plain: Second Year Results and Third Year Plan; Mars Global Geologic Mapping: About Half Way Done; New Geologic Map of the Scandia Region of Mars; Geologic Mapping of the Medusae Fossae Formation on Mars and the Northern Lowland Plains of Venus; Volcanism on Io: Insights from Global Geologic Mapping; and Planetary Geologic Mapping Handbook - 2009.

Radargrams Indicating Ice-Rich Subsurface Deposit

NASA Image and Video Library

2016-11-22

These two images show data acquired by the Shallow Radar (SHARAD) instrument while passing over two ground tracks in a part of Mars' Utopia Planitia region where the orbiting, ground-penetrating radar detected subsurface deposits rich in water ice. The instrument on NASA's Mars Reconnaissance Orbiter emits radio waves and times their echo off of radio-reflective surfaces and interfaces on Mars. The white arrows indicate a subsurface reflector interpreted as the bottom of the ice-rich deposit. The deposit is about as large in area as the state of New Mexico and contains about as much water as Lake Superior. The horizontal scale bar indicates 40 kilometers (25 miles) along the ground track of the radar, as flown by the orbiter overhead. The vertical scale bar indicates a return time of one microsecond for the reflected radio signal, equivalent to a distance of about 90 meters (295 feet). http://photojournal.jpl.nasa.gov/catalog/PIA21137

Topography of the Deuteronilus contact on Mars: Evidence for an ancient water/mud ocean and long-wavelength topographic readjustments

NASA Astrophysics Data System (ADS)

Ivanov, M. A.; Erkeling, G.; Hiesinger, H.; Bernhardt, H.; Reiss, D.

2017-09-01

In this paper, we present the results of our detailed study of morphology, topography, and age of the Deuteronilus contact that outlines Vastitas Borealis Formation (VBF) in the northern plains and the Isidis Planitia unit. The Deuteronilus contact represents a sharp and distinct geological boundary that can be traced continuously for many hundreds to thousands of kilometers. In the northern plains, segments of the Deuteronilus contact occur at two distinct topographic levels. In the northern plains, the long-wavelength topography of the Deuteronilus contact occur at two distinct topographic levels. In the Tempe, Chryse, Acidalia, and Cydonia-Deuteronilus regions (the total length is ∼14,000 km), the contact is at the mean elevation of about -3.92 km (the decile range is 180 m, from -4.01 km to -3.83 km). In the Pyramus-Astapus, Utopia, and Western Elysium regions (the total length is ∼7700 km), the mean elevation of the contact is about -3.58 km (the decile range is 270 m, from -3.73 km to -3.46 km). These levels to large extent (but not completely) correspond to the model geoids that may have been characterized the shape of Mars at the time of the VBF emplacement. Largest deviations of the actual topographic position of the contact from the model geoids occur in the Tantalus and Phlegra regions where the deviations are due to the post-VBF changes of the regional topography. The fact that the model geoids satisfactory describe the shape of the largest portion of the contact provides additional evidence for both the emplacement of the VBF edges near an equipotential surface and for relative stability of the shape of Mars during a long time interval of about 3.6 Ga. Within the northern plains in the Tempe Terra, Acidalia Planitia, Cydonia-Deuteronilus, Pyramus-Astapus, and the southern Utopia regions, the absolute model ages of the VBF surface near the Deuteronilus contact are tightly clustered around the age of ∼3.6 Ga, which we interpret as the age of the VBF emplacement. The surface of the VBF-like Isidis Planitia unit is distinctly younger, ∼3.50 ± 0.01 Ga, which suggests that this unit formed independently. Neither volcanic nor glacial modes of emplacement are consistent with the topographic configuration and the shape of the Deuteronilus contact within both the northern plains and in Isidis Planitia. The broad flooding and formation of extensive water/mud reservoirs remains to be the most plausible mode of formation of the VBF in the northern plains and the VBF-like unit on the floor of the Isidis basin.

New Support for Hypotheses of an Ancient Ocean on Mars

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Allen, Carlton C.

2013-01-01

A new analog for the giant polygons in the Chryse-Acidalia area suggests that those features may have formed in a major body of water - likely a Late Hesperian to Early Amazonian ocean. This analog -terrestrial polygons in subsea, passive margin basins derives from 3D seismic data that show similar-scale, polygonal fault systems in the subsurface of more than 50 terrestrial offshore basins. The terrestrial and martian polygons share similar sizes, basin-wide distributions, tectonic settings, and association with expected fine-grained sediments. Late Hesperian deposition from outflow floods may have triggered formation of these polygons, by providing thick, rapidly-deposited, fine-grained sediments necessary for polygonal fracturing. The restriction of densely occurring polygons to elevations below approx. -4000 m to -4100 m supports inferences that a body of water controlled their formation. Those same elevations appear to restrict occurrence of polygons in Utopia Planitia, suggesting that this analog may apply also to Utopia and that similar processes may have occurred across the martian lowlands.

Fine-Scale Layering of Mars Polar Deposits and Signatures of Ice Content in Nonpolar Material From Multiband SHARAD Data Processing

NASA Astrophysics Data System (ADS)

Campbell, Bruce A.; Morgan, Gareth A.

2018-02-01

The variation of Shallow Radar (SHARAD) echo strength with frequency reveals material dielectric losses and polar layer properties. Loss tangents for Elysium and Amazonis Planitiae deposits are consistent with volcanic flows and sediments, while the Medusae Fossae Formation, lineated valley fill, and lobate debris aprons have low losses consistent with a major component of water ice. Mantling materials in Arcadia and Utopia Planitiae have higher losses, suggesting they are not dominated by ice over large fractions of their thickness. In Gemina Lingula, there are frequent deviations from a simple dependence of loss on depth. Within reflector packets, the brightest reflectors are often different among the frequency subbands, and there are cases of reflectors that occur in only the high- or low-frequency echoes. Many polar radar reflections must arise from multiple thin interfaces, or single deposits of appropriate thickness, that display resonant scattering behaviors. Reflector properties may be linked to climate-controlled polar dust deposition.

Mars Boulders: On a Hill in Utopia Planitia

NASA Image and Video Library

2000-09-18

The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) was designed specifically to provide images of Mars that have a resolution comparable to the aerial photographs commonly used by Earth scientists to study geological processes and map landforms on our home planet. When MGS reaches its Mapping Orbit in March 1999, MOC will be able to obtain pictures with spatial resolutions of 1.5 meters (5 feet) per pixel--this good enough to easily see objects the size of an automobile. Boulders are one of the keys to determining which processes have eroded, transported, and deposited material on Mars (e.g.,landslides, mud flows, flood debris). During the first year in orbit,MGS MOC obtained pictures with resolutions between 2 and 30 meters (7to 98 feet) per pixel. It was found that boulders are difficult to identify on Mars in images with resolutions worse than about 2-3 meters per pixel. Although not known when the MOC was designed,"thresholds" like this are found on Earth, too. The MOC's 1.5 m/pixel resolution was a compromise between (1) the anticipation of such resolution-dependent sensitivity based on our experience with Earth and (2)the cost in terms of mass if we had built a larger telescope to get a higher resolution. Some rather larger boulders (i.e., larger than about 10 meters--or yards--in size) have already been seen on Mars by the orbiting camera. This is a feat similar to that which can be obtained by "spy" satellites on Earth. The MOC image 53104 subframe shown above features a low, rounded hill in southeastern Utopia Planitia. Each of the small, lumpy features on the top of this hill is a boulder. In this picture, boulders are not seen on the surrounding plain. These boulders are interpreted to be the remnants of a layer of harder rock that once covered the top of the hill, but was subsequently eroded and broken up by weathering and wind processes. MOC image 53104 was taken on September 2, 1998. The subframe shows an area 2.2 km by 3.3 km (1.4 miles by 2.7 miles). The image has a resolution of about 3.25 meters (10.7 feet) per pixel. The subframe is centered at 41.0°N latitude and 207.3°W longitude. North is approximately up, illumination is from the left. http://photojournal.jpl.nasa.gov/catalog/PIA01500

A Peek into a Cul-De-Sac and a Mews of Martian Dust Storm Activity: Western Hellas and Syria-Claritas Fossae During Mars Year 29

NASA Astrophysics Data System (ADS)

Heavens, N. G.

2016-12-01

Western Hellas Planitia (WHP) and the region encompassed by Syria Planum and Claritas Fossae are the main centers of textured dust storm activity in Mars's southern low to mid-latitudes. (Texture in this context refers to distinct fine structure at the cloud tops indicative of active lifting.) WHP is a well-known initiation zone for regional and global dust storm activity and often the end point of the Utopia "flushing storm" track. Syria-Claritas Fossae (SCF), too, can be a lifting center in global dust storm activity. Indeed, SCF and the area to its west was the region most denuded of dust by the Mars Year (MY) 25 global dust storm, perhaps suggesting that SCF contained the principal lifting center of the storm. Thus, if the Acidalia and Utopia storm tracks are Mars's dust storm alleys, through which dust storms pass quickly again and again; WHP might be a cul-de-sac and SCF something like a mews, where dust storm activity can enter more or less easily but may not as easily leave. In this presentation, I will focus on dust storm activity in these areas in a typical non-global dust storm year, MY 29. Synthesizing visible imagery by the Mars Color Imager (MARCI) on board Mars Reconnaissance Orbiter (MRO) and Mars Climate Sounder (MCS) also on board MRO, I will consider the climatology, morphology, texture, and vertical structure of dust storm activity in these areas in order to infer their governing dynamics. This investigation has two aims: (1) to understand why these areas are centers of textured dust storm activity; and (2) to connect the characteristics of smaller-scale dust storm activity in these regions to the underlying dynamics in order to understand the role of WHP and SCF in the dynamics of global dust storms. This work is supported by NASA's Mars Data Analysis Program (NNX14AM32G).

Viking Lander 2 Anniversary

NASA Image and Video Library

2002-12-13

This portion of NASA Mars Odyssey image covers NASA Viking 2 landing site shown with the X. The second landing on Mars took place September 3, 1976 in Utopia Planitia. The exact location of Lander 2 is not as well established as Lander 1 because there were no clearly identifiable features in the lander images as there were for the site of Lander 1. The Utopia landing site region contains pedestal craters, shallow swales and gentle ridges. The crater Goldstone was named in honor of the Tracking Station in the desert of California. The two Viking Landers operated for over 6 years (nearly four martian years) after landing. This one band IR (band 9 at 12.6 microns) image shows bright and dark textures, which are primarily due to differences in the abundance of rocks on the surface. The relatively cool (dark) regions during the day are rocky or indurated materials, fine sand and dust are warmer (bright). Many of the temperature variations are due to slope effects, with sun-facing slopes warmer than shaded slopes. The dark rings around several of the craters are due to the presence of rocky (cool) material ejected from the crater. These rocks are well below the resolution of any existing Mars camera, but THEMIS can detect the temperature variations they produce. Daytime temperature variations are produced by a combination of topographic (solar heating) and thermophysical (thermal inertia and albedo) effects. Due to topographic heating the surface morphologies seen in THEMIS daytime IR images are similar to those seen in previous imagery and MOLA topography. http://photojournal.jpl.nasa.gov/catalog/PIA04023

Center is at Latitude 30 Degrees South, Longitude 210 Degrees

NASA Image and Video Library

1998-06-08

The lowland plains of Elysium and Utopia Planitiae are separated from the darker heavily cratered highlands by a broad escarpment in this image from NASA's Viking Orbiter 1. http://photojournal.jpl.nasa.gov/catalog/PIA00196

The surface of Mars: the view from the viking 2 lander.

PubMed

Mutch, T A; Grenander, S U; Jones, K L; Patterson, W; Arvidson, R E; Guinness, E A; Avrin, P; Carlston, C E; Binder, A B; Sagan, C; Dunham, E W; Fox, P L; Pieri, D C; Huck, F O; Rowland, C W; Taylor, G R; Wall, S D; Kahn, R; Levinthal, E C; Liebes, S; Tucker, R B; Morris, E C; Pollack, J B; Saunders, R S; Wolf, M R

1976-12-11

Viking 2 lander began imaging the surface of Mars at Utopia Planitia on 3 September 1976. The surface is a boulder-strewn reddish desert cut by troughs that probably form a polygonal network. A plateau can be seen to the east of the spacecraft, which for the most probable lander location is approximately the direction of a tongue of ejecta from the crater Mie. Boulders at the lander 2 site are generally more vesicular than those near lander i. Fines at both lander sites appear to be very fine-grained and to be bound in a duricrust. The pinkish color of the sky, similar to that observed at the lander I site, indicates suspension of surface material. However, the atmospheric optical depth is less than that at the lander I site. After dissipation of a cloud of dust stirred during landing, no changes other than those stemming from sampling activities have been detected in the landscape. No signs of large organisms are apparent at either landing site.

The surface of Mars - The view from the Viking 2 lander

NASA Technical Reports Server (NTRS)

Mutch, T. A.; Grenander, S. U.; Jones, K. L.; Patterson, W.; Arvidson, R. E.; Guinness, E. A.; Avrin, P.; Carlston, C. E.; Binder, A. B.; Sagan, C.

1976-01-01

Viking 2 lander began imaging the surface of Mars at Utopia Planitia on September 3, 1976. The surface is a boulder-strewn reddish desert cut by troughs that probably form a polygonal network. A plateau can be seen to the east of the spacecraft, which for the most probable lander location is approximately the dirction of a tongue of ejecta from the crater Mie. Boulders at the lander 2 site are generally more vesicular than those near lander 1. Fines at both lander sites appear to be very fine-grained and to be bound in a duricrust. The pinkish color of the sky, similar to that observed at the lander 1 site, indicates suspension of surface material. However, the atmospheric optical depth is less than that at the lander 1 site. After dissipation of a cloud of dust stirred during landing, no changes other than those stemming from sampling activities have been detected in the landscape. No signs of large organisms are apparent at either landing site.

Mapping the northern plains of Mars: origins, evolution and response to climate change

NASA Astrophysics Data System (ADS)

Balme, Matthew; Conway, Susan; Costard, François; Gallagher, Colman; van Gasselt, Stephan; Hauber, Ernst; Johnsson, Andreas; Kereszturi, Akos; Platz, Thomas; Ramsdale, Jason; Reiss, Dennis; Séjourné, Antoine; Skinner, James; Swirad, Zuzanna

2014-05-01

An ISSI (International Space Science Institute) international team has been convened to study the Northern Plain of Mars. The northern plains are extensive, geologically young, low-lying areas that contrast in age and relief to Mars' older, heavily cratered, southern highlands. Mars' northern plains are characterised by a wealth of landforms and landscapes that have been inferred to be related to the presence of ice or ice-rich material near, beneath, or at the surface. Such landforms include 'scalloped' pits and depressions, polygonally-patterned grounds, and viscous flow features similar in form to terrestrial glacial or ice-sheet landforms. Furthermore, new (within the last few years) impact craters have exposed ice in the northern plains, and spectral data from orbiting instruments have revealed the presence of tens of percent by weight of water within the upper most ~50 cm of the martian surface at high latitudes. The northern plains comprise three linked zones: Acidalia Planitia, Utopia Planitia and Arcadia Planitia. Each region consists of a shallow basin, with the three areas are separated by low topographic divides. Our aim is to study the ice-related geomorphology of each region in order to understand the origins, evolution and response to climate change of ice on Mars. In particular, by comparing and contrasting the three separate basins we hope to determine if the processes that created the ice-related terrains are regional (perhaps basin limited) or global in scope, and whether the differing geology of each basin has an effect on the ice-related features observed there. The ISSI team is using planetary geomorphological mapping to meet this aim. Three long strips, each about 250 km wide and spanning the ~30N to ~80N latitude range have been defined and sub-teams are each mapping a single area. The group contains experts in mapping, GIS and crater counting (details in the size-frequency distribution of impact craters on a planetary surface can reveal information about when terrains were emplaced, modified, eroded or exhumed). The first meeting of this group was held in December 2013. Here, we give an overview of the science aims of the project, describe the main difference between the three strips and report on mapping work done so far.

Abstracts of the Annual Meeting of Planetary Geologic Mappers, Flagstaff, AZ, 2010

NASA Technical Reports Server (NTRS)

Bleamaster, Leslie F., III (Editor); Tanaka, Kenneth L. (Editor); Kelley, Michael S. (Editor)

2010-01-01

Topics covered include: Detailed Analysis of the Intra-Ejecta Dark Plains of Caloris Basin, Mercury; The Formation and Evolution of Tessera and Insights into the Beginning of Recorded History on Venus: Geology of the Fortuna Tessera Quadrangle (V-2); Geologic Map of the Snegurochka Planitia Quadrangle (V-1): Implications for the Volcanic History of the North Polar Region of Venus; Geological Map of the Fredegonade (V-57) Quadrangle, Venus: Status Report; Geologic Mapping of V-19; Geology of the Lachesis Tessera Quadrangle (V-18), Venus; Comparison of Mapping Tessera Terrain in the Phoebe Regio (V-41) and Tellus Tessera (V-10) Quadrangles; Geologic Mapping of the Devana Chasma (V-29) Quadrangle, Venus; Geologic Mapping of the Aristarchus Plateau Region on the Moon; Geologic Mapping of the Lunar South Pole Quadrangle (LQ-30); The Pilot Lunar Geologic Mapping Project: Summary Results and Recommendations from the Copernicus Quadrangle; Geologic Mapping of the Nili Fossae Region of Mars: MTM Quadrangles 20287, 20282, 25287, 25282, 30287, and 30282; Geologic Mapping of the Mawrth Vallis Region, Mars: MTM Quadrangles 25022, 25017, 25012, 20022, 20017, and 20012; Evidence for an Ancient Buried Landscape on the NW Rim of Hellas Basin, Mars; New Geologic Map of the Argyre Region of Mars: Deciphering the Geologic History Through Mars Global Surveyor, Mars Odyssey, and Mars Express Data; Geologic Mapping in the Hesperia Planum Region of Mars; Geologic Mapping of the Meridiani Region of Mars; Geologic Mapping in Southern Margaritifer Terra; Geology of -30247, -35247, and -40247 Quadrangles, Southern Hesperia Planum, Mars; The Interaction of Impact Melt, Impact-Derived Sediment, and Volatiles at Crater Tooting, Mars; Geologic Map of the Olympia Cavi Region of Mars (MTM 85200): A Summary of Tactical Approaches; Geology of the Terra Cimmeria-Utopia Planitia Highland Lowland Transitional Zone: Final Technical Approach and Scientific Results; Geology of Libya Montes and the Interbasin Plains of Northern Tyrrhena Terra, Mars: First Year Results and Second Year Work Plan; Mars Global Geologic Mapping Progress and Suggested Geographic-Based Hierarchal Systems for Unit Grouping and Naming; Progress in the Scandia Region Geologic Map of Mars; Geomorphic Mapping of MTMS -20022 and -20017; Geologic Mapping of the Medusae Fossae Formation, Mars, and the Northern Lowland Plains, Venus; Volcanism on Io: Results from Global Geologic Mapping; Employing Geodatabases for Planetary Mapping Conduct - Requirements, Concepts and Solutions; and Planetary Geologic Mapping Handbook - 2010.

Geologic history of central Chryse Planitia and the Viking 1 landing site, Mars

NASA Technical Reports Server (NTRS)

Craddock, Robert A.; Crumpler, L. S.; Aubele, Jayne C.

1993-01-01

A 1:500,000 scale geologic mapping was undertaken to synthesize the broad-scale geology of Chryse Planitia with the local geology of the Viking 1 landing site. The geology of Mars Transverse Mercators (MTM's) 20047 and 25047 has been presented previously. As part of the goals for the Mars Geologic Mapping program, the rational and scientific objectives for a return mission to Chryse Planitia and the Viking 1 Lander have also been presented. However, in mapping central Chryse Planitia our principle objective was to determine the depositional and erosional history of the Chryse Planitia basin. These results are presented.

Relative Ages of the Highlands, Lowlands, and Transition Zone Along a Portion of the Mars Crustal Dichotomy from Densities of Visible and Buried Impact Craters

NASA Technical Reports Server (NTRS)

DeSoto, G. E.; Frey, H. V.

2005-01-01

Understanding the fundamental age relationships of the different parts of the Mars Crustal Dichotomy is essential to fully understanding the events that shaped the early history and formation of the surface of Mars. A dominant question is what are the true relative ages of the Northern Lowlands and the Southern Highlands? Using MOLA data from the Mars Global Surveyor and Viking visual images, a dataset of both buried and visible crater diameters was created over a nine million sq km study area of a section of the dichotomy boundary stretching from Arabia Terra to Utopia Planitia. Cumulative frequency plots on a log-log scale were used to determine the relative ages for the Highlands, the Lowlands, and the Transition Zone, separately for the visible, the buried and the combined total (visible+ buried) populations. We find the overall Highland crater population in this area is slightly older than the Lowlands, consistent with previous global studies, but the Lowlands and Transition Zone are also very old and formed at roughly the same time. It appears that the formation of the Lowlands in this region formed contemporaneously with a large-scale resurfacing event in the Highlands, perhaps caused by the process responsible for the Lowland formation.

Genesis Hypotheses Concerning Putative Rootless Cone Groups in Isidis Planitia, Mars

NASA Astrophysics Data System (ADS)

Pithawala, T. M.; Ghent, R. R.

2008-09-01

ABSTRACT Introduction Isidis Planitia is one of the many areas on Mars containing thumbprint terrain (TPT), a term coined to reflect the resemblance in Viking images to fingerprints. Other instances occur in Argyre, Hellas, Arcadia Planitia, and Utopia Planitia. The terrain is found where Greeley and Guest (1987) have defined the Hesperian Ridged Plains (Hvr) unit. However, landforms comprising the TPT in Isidis are markedly different in morphology from those in the northern plains. The purpose of this study is to conduct a systematic examination of the TPT in Isidis Planitia using high-resolution imagery, and to propose a hypothesis for its genesis. Northern Plains TPT Morphology: TPT landforms include branching troughs and medial ridges forming whorled lobes and mounds, most with basal scarps or terraces. TPT has been described as consisting of parallel, en echelon, or nested sets of regularly spaced curvilinear ridges or aligned hills [1]. The ridges were estimated to be 0.5-2.5 km wide and 1-40 km long, with a characteristic spacing of 2-6 km. Whorled lobes of TPT are 75-150 km wide, with heights ranging from 10-200 m. Previous work identified 22 areas of TPT, covering 3000- 420,000 km2 in the Northern Plains at elevations between 0 and -2 km. In Utopia, TPT includes branching troughs and medial ridges [5], and TPT is closely associated with troughs in at least 9 other Northern Plains areas [1]. Northern Plains TPT Origin: MOLA topography supports the hypothesis that TPT and associated trough systems in Utopia and Arcadia Planitae are glacial features [1,2,3]. Possible mechanisms include formation of ridges as moraines and troughs as eskers formed by wet-based continental glaciers. The absence of drumlin fields suggests that the glaciers responsible for forming the topography may have been cold-based and thus did not deform the substrate so as to form drumlins [4]. A puzzling characteristic of Mars alleged glacial landscapes is that they are morphologically pristine, though they must be at least hundreds of millions of years old [1]. Isidis TPT The physical appearance of the Isidis features differs from that of the Northern Plains TPT. Isisdis TPT includes wrinkle ridges and curvilinear ridges. Wrinkle ridges are oriented radially and concentric to the basin structure, form cells of 180 km in diameter, and occur throughout the basin over a range of elevations. They are on the order of 75-150 m high and less than 70 km wide [6]. In this study, we focus on the curvilinear ridges and associated features, using THEMIS daytime IR data. Curvilinear ridges are ˜10-50 m high, and <5 km wide, with a large number 1km wide. Ridges consist of connected cones with central depressions (30-50 % of basal diameter). Cones are often connected to each other midway through their height but sometimes share portions of their rims as well. Basal diameters of the cones vary from 600-1000 m (nearly twice the size of cones seen in northern plains TPT) [6]. Spatial Patterns Closely spaced ridges are sub-parallel to parallel. Mapping of TPT features in Isidis Planitia shows four domains of distinct morphology (Figure 1). Domain 1 consists of chain-like ridges of cones concentrated to the southern and western regions of the basin. Domain 2 consists of isolated cones localized in the basin center. Domain 3 is the Syrtis Major Isidis Planitia transition zone and consists of clusters of knobs, mesas, and large single scarps [7]. Domain 4 (west of the transition zone and along the outer regions of the basin) consists of smooth terrain lacking a significant number of cones, or knobs and mesas. The most detailed mapping in this study has been completed for Domains 1 and 2. In Domain 1, an apparent pattern emerges along a boundary trending E-W at 12 N. Cone-chains located north of this boundary show a preferential N-S alignment, convex toward the east. Cone-chains located south of the boundary show a preferential E-W alignment, convex toward the south. Cone-chains occupy the region previously mapped as Hvr [8]. Origin of the Isidis TPT features Glacial formation mechanisms are generally accepted for formation of TPT in Argyre, Hellas, Arcadia, and Utopia. The TPT of Isidis Planitia is markedly different in morphology, and so deserves a fresh examination. We look to terrestrial analogues of rootless cones. The underlying mechanism is the interaction between magma (or lava) with a volatile (possibly water) rich substrate. Top-heating A top-heating model would involve lava flows and Vastitas Borealis Formation (VBF) materials known to cover the floor of Isidis [7]. In this model, Syrtis Major eruptions would produce tube-fed lava flows overlying volatile-rich materials derived from the Northern Plains, heating the wet substrate from above; interaction between the hot lava tubes and the substrate would produce chains of rootless cones. This model is expected to play a role in the formation of the TPT features, though it is doubtful if it can act solely to form the features, because the model is topography dependent and cannot readily account for both large- and smallscale patterns. Bottom-Heating The spatial patterns seen in planview of TPT in Isidis Planitia show a strong similarity to surface and seismic expressions of sills the Karoo basin in South Africa and the North Rockall Trough in the NE Atlantic on Earth. This leads to the idea that a sill or cone sheet complex beneath the Isidis basin, possibly linked to Syrtis Major, could drive bottom heating of a volatile rich substrate, leading to the formation of aligned rootless cones comprising the thumbprint terrain of Isidis Planitia. Though similar to the top-heating model, a system of intrusive structures heating from below would be independent of the current local topography of the basin, and is thus favorable. Such a mechanism could further explain the small-scale deviations in spatial alignment from the regional trend. The branch-like evolution of a sill complex can result in the non-uniform development of sills [11], such that daughter bodies of a parent sill can vary in size and vertical and horizontal distribution, and thus result in different abutment relationships, causing varying surface manifestations of the hybrid sill tips. A combination of both models is also a likely candidate for the genesis of TPT in Isidis. We are continuing to investigate the details of the two models by analyzing additional datasets and terrestrial analogues. References [1] Kargel et al. (1995) JGR-E, 100, 5351-5368. [2] Pomerantz, W.J and Head III, J.W (2003) LPSC XXXXIII, Abstract 1277. [3] Chapman M. (1994) Icarus, 109(2), 393-406. [4] Head III, J.W and Marchant (2003) LPSC XXXXIII, Abstract 1247. [5] Scott and Underwood (1991) Proceedings of Lunar Planet. Sci, 21, 627-634. [6] Hiesinger, H. and Head III, J.W (2003) 6th Intl Conf. on Mars, Abstract 3061. [7] Ivanov, M.A and Head III, J.W (2003) JGR-E, 108, E6. [8] Greeley, R. and Guest, J.E (1987), US Geol. Surv. Misc. Invest. Ser., Map I-1802-B. [9] Cartwright, J. and Hansen, D.M (2006) Geology 34(11), 929-932. [10] Hansen, D.M and Cartwright, J. (2006) Journal Geol. Soc. London 163 (3), 509-523. [11] Thomson, K., and Hutton, D. (2004) Bull Volcanology, 66, 364-375.

A model for the origin of Martian polygonal terrain

NASA Technical Reports Server (NTRS)

Mcgill, G. E.

1993-01-01

Extensive areas of the Martian northern plains in Utopia and Acidalia Planitiae are characterized by 'polygonal terrain.' Polygonal terrain consists of material cut by complex troughs defining a pattern resembling mudcracks, columnar joints, or frost-wedge polygons on the Earth. However, the Martian polygons are orders of magnitude larger than these potential Earth analogs, leading to severe mechanical difficulties for genetic models based on simple analogy arguments. Stratigraphic studies show that the polygonally fractured material in Utopia Planitia was deposited on a land surface with significant topography, including scattered knobs and mesas, fragments of ancient crater rims, and fresh younger craters. Sediments or volcanics deposited over topographically irregular surfaces can experience differential compaction producing drape folds. Bending stresses due to these drape folds would be superposed on the pervasive tensile stresses due to desiccation or cooling, such that the probability of fracturing is enhanced above buried topographic highs and suppressed above buried topographic lows. Thus it was proposed that the scale of the Martian polygons is controlled by the spacing of topographic highs on the buried surface rather than by the physics of the shrinkage process.

Triple-Crater in Elysium Planitia

NASA Image and Video Library

2015-01-22

This image from NASA Mars Mars Reconnaissance Orbiter shows a triple impact crater in Elysium Planitia near Tartarus Montes, which probably formed when a binary-or even triple-asteroid struck the surface.

Evidence for and implications of sedimentary diapirism and mud volcanism in the southern Utopia highland-lowland boundary plain, Mars

USGS Publications Warehouse

Skinner, J.A.; Tanaka, K.L.

2007-01-01

Several types of spatially associated landforms in the southern Utopia Planitia highland-lowland boundary (HLB) plain appear to have resulted from localized geologic activity, including (1) fractured rises, (2) elliptical mounds, (3) pitted cones with emanating lobate materials, and (4) isolated and coalesced cavi (depressions). Stratigraphic analysis indicates these features are Hesperian or younger and may be associated with resurfacing that preferentially destroyed smaller (< 8 ?? km diameter) impact craters. Based on landform geomorphologies and spatial distributions, the documented features do not appear to be specifically related to igneous or periglacial processes or the back-wasting and erosion of the HLB scarp. We propose that these features are genetically related to and formed by sedimentary (mud) diapirs that ascended from zones of regionally confined, poorly consolidated, and mechanically weak material. We note morphologic similarities between the mounds and pitted cones of the southern Utopia boundary plain and terrestrial mud volcanoes in the Absheron Peninsula, Azerbaijan. These analogs provide a context for understanding the geological environments and processes that supported mud diapir-related modification of the HLB. In southern Utopia, mud diapirs near the Elysium volcanic edifice may have resulted in laccolith-like intrusions that produced the fractured rises, while in the central boundary plain mud diapirs could have extruded to form pitted cones, mounds, and lobate flows, perhaps related to compressional stresses that account for wrinkle ridges. The removal of material a few kilometers deep by diapiric processes may have resulted in subsidence and deformation of surface materials to form widespread cavi. Collectively, these inferences suggest that sedimentary diapirism and mud volcanism as well as related surface deformations could have been the dominant Hesperian mechanisms that altered the regional boundary plain. We discuss a model in which detritus would have accumulated thickly in the annular spaces between impact-generated structural rings of Utopia basin. We envision that these materials, and perhaps buried ejecta of Utopia basin, contained volatile-rich, low-density material that could provide the source material for the postulated sedimentary diapirs. Thick, water-rich, low-density sediments buried elsewhere along the HLB and within the lowland plains may account for similar landforms and resurfacing histories. ?? 2006 Elsevier Inc. All rights reserved.

Viking Lander Model

NASA Technical Reports Server (NTRS)

2007-01-01

NASA's Viking Project found a place in history when it became the first mission to land a spacecraft successfully on the surface of another planet and return both imaging and non-imaging data over an extended time period. Two identical spacecraft, each consisting of a lander and an orbiter, were built. Each orbiter-lander pair flew together and entered Mars orbit; the landers then separated and descended to the planet's surface.

The Viking 1 Lander touched down on the western slope of Chryse Planitia (the Plains of Gold) on July 20, 1976, while the Viking 2 lander settled down at Utopia Planitia on September 3, 1976.

Besides taking photographs and collecting other science data on the Martian surface, the two landers conducted three biology experiments designed to look for possible signs of life. These experiments discovered unexpected and enigmatic chemical activity in the Martian soil, but provided no clear evidence for the presence of living microorganisms in soil near the landing sites. According to scientists, Mars is self-sterilizing. They believe the combination of solar ultraviolet radiation that saturates the surface, the extreme dryness of the soil and the oxidizing nature of the soil chemistry prevent the formation of living organisms in the Martian soil.

The Viking mission was planned to continue for 90 days after landing. Each orbiter and lander operated far beyond its design lifetime. Viking Orbiter 1 functioned until July 25, 1978, while Viking Orbiter 2 continued for four years and 1,489 orbits of Mars, concluding its mission August 7, 1980. Because of the variations in available sunlight, both landers were powered by radioisotope thermoelectric generators -- devices that create electricity from heat given off by the natural decay of plutonium. That power source allowed long-term science investigations that otherwise would not have been possible. The last data from Viking Lander 2 arrived at Earth on April 11, 1980. Viking Lander 1 made its final transmission to Earth November 11, 1982.

Corrigendum to "Energetics of the Martian Atmosphere Using the Mars Analysis Correction Data Assimilation (MACDA) Dataset" [Icarus 276 (2016) 1-20

NASA Astrophysics Data System (ADS)

Battalio, Michael; Szunyogh, Istvan; Lemmon, Mark

2018-03-01

A coding error resulted in the barotropic energy conversion (BTEC) term taking the wrong sign throughout the paper. All figures showing BTEC, whether as an average or an instantaneous field, should have the sign swapped. This change alters the following conclusions: BTEC acts as a source of eddy kinetic energy on the upstream side of the storm tracks, namely in Acidalia Planitia and Utopia Planitia, and as a sink just upstream of the highest topography. BTEC is a weak source of eddy kinetic energy closer to the surface, but is a strong source above 10 Pa. The main conclusion that waves decay by BTEC and that waves in high opacity situations grow via BTEC remains, but there is also a positive contribution toward the EKE by the BTEC during the growth periods of waves, even in low-opacity situations. These changes make the resulting BTEC more inline to that of other modeling efforts (Barnes et al., 1993; Greybush et al., 2013; Tabataba-vakili et al., 2015), observations (e.g., Banfield et al., 2004), and terrestrial studies (Chang, 2001; Chang et al., 2002; Decker and Martin, 2005; Ahmadi-Givi et al., 2014; Herrera et al., 2016). The new BTEC also slightly modifies the residue shown in Fig. 6, but the qualitative conclusions for the residue remain unchanged.

The Martian surface as imaged, sampled, and analyzed by the Viking landers

NASA Technical Reports Server (NTRS)

Arvidson, Raymond E.; Gooding, James L.; Moore, Henry J.

1989-01-01

Data collected by two Viking landers are analyzed. Attention is given to the characteristics of the surface inferred from Lander imaging and meteorology data, physical and magnetic properties experiments, and both inorganic and organic analyses of Martian samples. Viking Lander 1 touched down on Chryse Planitia on July 20, 1976 and continued to operate for 2252 sols, until November 20, 1982. Lander 2 touched down about 6500 km away from Lander 1, on Utopia Planitia on September 3, 1976. The chemical compositions of sediments at the two landing sites are similar, suggesting an aeolian origin. The compositions suggest an iron-rich rock an are matched by various clays and salts.

Chryse Planitia, Mars: Topographic configuration, outflow channel continuity and sequence, and tests for hypothesized ancient bodies of water using Mars Orbiter Laser Altimeter (MOLA) data

NASA Astrophysics Data System (ADS)

Ivanov, M. A.; Head, J. W.

2001-02-01

Many of the largest and most prominent outflow channels on Mars debouch into Chryse Planitia. Pre-Mars Global Surveyor topographic data show Chryse to be a closed depression almost 2000 km in diameter. New Mars Orbiter Laser Altimeter (MOLA) data reveal the following: (1) Chryse is not a locally closed basin but instead opens into the North Polar basin. (2) The highly distinctive morphology of the six largest predominantly Hesperian-aged channels (Kasei, Maja, Simud, Tiu, Ares, and Mawrth) disappears into the northern lowlands at average elevations that all occur within less than ~170 m of a mean elevation of -3742(SD=153m), over a lateral distance in excess of 2500 km. (3) The elevations where the distinctive morphology of each channel disappears all fall within ~190 m of Contact 2, a boundary mapped by Parker et al. [1993] and interpreted to represent an ancient shoreline, and the mean elevation values of Contact 2 and circum-Chryse channel termini fall within 18 m of each other. In contrast, the termini of seven later Amazonian-aged channels emerging from Elysium into Utopia Planitia are spread over a vertical range of >1500 m. (4) Topographic evidence of the continuation of some of the outflow channels can be observed for distances of 250-450 km into the North Polar basin, but the morphology is subdued and distinctly different. (5) The nature of this less distinctive topography and its crosscutting relationships show that Simud and Tiu are likely to represent the youngest activity (specifically crosscutting Ares Valles). (6) The distinctive change in channel morphology is consistent with rapid loss of energy encountered at base level (subaerial/submarine boundary) and emplacement into a shallow submarine environment. Channel characteristics, lack of distinctive deltas or lobes, and continuation of subdued channel morphology suggest hyperpychnal flow and the possibility of density/turbidity currents. Estimates of the volumes of individual channel events are wide-ranging. The minimum volume estimates of Carr [1996] suggest that 46 such events would be required to fill the basin to the level of Contact 2 and thus that the channels may have emptied into an existing standing body of water. Volume estimates of Baker et al. [1991] assume that single individual events may have filled the basin to the level of Contact 2, thus requiring significant water loss between events and refilling during subsequent events to essentially the same level. In both end-member cases these observations are consistent with the presence of large standing bodies of water in the northern lowlands in Hesperian-Early Amazonian times.

HiRISE Characterization of Thermophysical Units at Acidalia Planitia, Mars

NASA Astrophysics Data System (ADS)

Martinez-Alonso, S.; Mellon, M. T.; Rafkin, S. C. R.; Zurek, R. W.; McEwen, A. S.; Putzig, N. E.; Searls, M. L.; HiRISE Team

2008-03-01

As part of an ongoing effort to characterize with HiRISE data the global thermophysical units in Mars, we report results regarding a region of Acidalia Planitia, which includes the largest outcrop of thermophysical unit F (rocks, bedrock, duricrust) on the planet.

Speculations on the origin and evolution of the Utopia-Elysium lowlands of Mars

NASA Technical Reports Server (NTRS)

Frey, Herbert V.; Schultz, Richard A.

1990-01-01

This paper proposes a qualitative model for the origin of the Utopia-Elysium northern lowlands on eastern Mars in terms of the long-term evolution of two large overlapping impact basins. The model, which is consistent with both the observed geologic constraints and more quantitative results obtained by numerical modeling of smaller (Orientale-size) impact basins, is shown to qualitatively account for the major topographic variation seen in the Utopia-Elysium region, including the overall 'lowness' of the area and localized depressions.

Habitable periglacial landscapes in martian mid-latitudes

NASA Astrophysics Data System (ADS)

Ulrich, M.; Wagner, D.; Hauber, E.; de Vera, J.-P.; Schirrmeister, L.

2012-05-01

Subsurface permafrost environments on Mars are considered to be zones where extant life could have survived. For the identification of possible habitats it is important to understand periglacial landscape evolution and related subsurface and environmental conditions. Many landforms that are interpreted to be related to ground ice are located in the martian mid-latitudinal belts. This paper summarizes the insights gained from studies of terrestrial analogs to permafrost landforms on Mars. The potential habitability of martian mid-latitude periglacial landscapes is exemplarily deduced for one such landscape, that of Utopia Planitia, by a review and discussion of environmental conditions influencing periglacial landscape evolution. Based on recent calculations of the astronomical forcing of climate changes, specific climate periods are identified within the last 10 Ma when thaw processes and liquid water were probably important for the development of permafrost geomorphology. No periods could be identified within the last 4 Ma which met the suggested threshold criteria for liquid water and habitable conditions. Implications of past and present environmental conditions such as temperature variations, ground-ice conditions, and liquid water activity are discussed with respect to the potential survival of highly-specialized microorganisms known from terrestrial permafrost. We conclude that possible habitable subsurface niches might have been developed in close relation to specific permafrost landform morphology on Mars. These would have probably been dominated by lithoautotrophic microorganisms (i.e. methanogenic archaea).

The Martian surface as imaged, sampled, and analyzed by the Viking landers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arvidson, R.E.; Gooding, J.L.; Moore, H.J.

1989-02-01

Data collected by two Viking landers are analyzed. Attention is given to the characteristics of the surface inferred from Lander imaging and meteorology data, physical and magnetic properties experiments, and both inorganic and organic analyses of Martian samples. Viking Lander 1 touched down on Chryse Planitia on July 20, 1976 and continued to operate for 2252 sols, until November 20, 1982. Lander 2 touched down about 6500 km away from Lander 1, on Utopia Planitia on September 3, 1976. The chemical compositions of sediments at the two landing sites are similar, suggesting an aeolian origin. The compositions suggest an iron-richmore » rock an are matched by various clays and salts. 89 refs.« less

Inorganic analyses of Martian surface samples at the Viking landing sites

NASA Technical Reports Server (NTRS)

Clark, B. C.; Castro, A. J.; Rowe, C. D.; Baird, A. K.; Evans, P. H.; Rose, H. J., Jr.; Toulmin, P., III; Keil, K.; Kelliher, W. C.

1976-01-01

Elemental analyses of fines in the Martian regolith at two widely separated landing sites, Chryse Planitia and Utopia Planitia, produced remarkably similar results. At both sites, the uppermost regolith contains abundant Si and Fe, with significant concentrations of Mg, Al, S, Ca, and Ti. The S concentration is one to two orders of magnitude higher, and K (less than 0.25% by weight) is at least 5 times lower than the average for earth's crust. The trace elements Sr, Y, and possibly Zr have been detected at concentrations near or below 100 parts per million. Pebble-sized fragments sampled at Chryse contain more S than the bulk fines and are thought to be pieces of a sulfate-cemented duricrust.

Inorganic analyses of martian surface samples at the viking landing sites.

PubMed

Clark, B C; Baird, A K; Rose, H J; Toulmin, P; Keil, K; Castro, A J; Kelliher, W C; Rowe, C D; Evans, P H

1976-12-11

Elemental analyses of fines in the Martian regolith at two widely separated landing sites, Chryse Planitia and Utopia Planitia, produced remarkably similar results. At both sites, the uppermost regolith contains abundant Si and Fe, with significant concentrations of Mg, Al, S, Ca, and Ti. The S concentration is one to two orders of magnitude higher, and K(<0.25 percent by weight) is at least 5 times lower than the average for the earth's crust. The trace elements Sr, Y, and possibly Zr, have been detected at concentrations near or below 100 parts per million. Pebblesized fragments sampled at Chryse contain more S than the bulk fines, and are thought to be pieces of a sulfate-cemented duricrust.

Preliminary results of the search for possible Martian landing sites to be considered for future European exploration missions

NASA Astrophysics Data System (ADS)

Martin, P.

2007-08-01

The recently adopted European Space Policy aims at expanding and coordinating the role and activities of Europe's space actors with the purpose of increasing both scientific knowledge in selected space domains and the European presence in the Solar System, as well as optimising the relevant societal benefits. With our Moon and in particular Mars as primary targets of exploration goals for the Solar System, and following a number of very successful orbital missions performing detailed remote sensing and mapping of these planetary bodies, probe landings on the surface of the Moon and Mars represent the next stepping stone of the exploration of our close planetary environment. Along with developing the hardware capabilities required for Europe to reach such ambitious goals, it therefore becomes increasingly important to pinpoint with precision a number of landing sites well suited for the safety and scientific success of future robotic missions. Focusing on Mars, and although a number of candidate landing sites and associated catalogs with available scientific justification already exist, the results being obtained by orbiters such as Mars Express and Mars Reconnaissance Orbiter are fundamentally transforming our knowledge of the planet's surface, which in turns highlights the need to review, update and revise the candidate sites for future landing missions on Mars. Detailed investigations of possible future Martian landing sites for European missions are ongoing, based on the wealth of scientific data and high-resolution mapping products available. In order to support the identification of suitable sites, various mapping products (geological, hyperspectral and compositional) can be consolidated, and various areas of Mars identified in the recent scientific literature as primary targets for landing can be taken into account for further, refined assessment of their suitability for landing. Seasonal and climatic effects potentially influencing landing shall also be considered, as well as lessons learned from past landing experiences. Finally, nolanding zones shall be identified based on a number of available criteria. A preliminary investigation and classification of potential landing sites for future European Mars exploration missions is summarised here, with the assumed following general requirements: • Moderate latitudes (e.g., 15ºS to 45ºN). Such a latitude range would be suitable for Exomars. • Low-to-moderate elevation (e.g., below 2000 m) • Relatively flat surface in the landing ellipse (e.g., slopes < 15º) • Low-to-moderate rock abundance (e.g., < 20%) • Moderate thermal inertia (rock/dust abundance) • Suitability to overriding scientific goals and targets of interest (e.g., niches of extant life, olivine sites, or sites where phyllosilicates or hydrated sulfates were identified) • Other constraints that shall be taken into account in a more detailed study: - Atmospheric and aeolian activity - Power and communications systems requirements - Illumination and temperature requirements - Biological potential and planetary protection Possible landing regions on Mars resulting from this preliminary investigation can be categorised into two classes, depending on the level of risk assessed for the landing in terms of, e.g., roughness and rock abundance: • Low-risk regions: Amazonis Planitia, Utopia Planitia, and Elysium Planitia. One of their potential drawbacks is that most areas of these regions exhibit a relatively high dust index which could be detrimental to the scientific interest of the in-situ mission. • Moderate-risk regions: - Syrtis Major / Nili Fossae, where phyllosilicates and hydrated minerals can be found based on recent evidence from orbit (Mars Express/OMEGA). - Isidis Planitia, in particular because this region presents a low vertical roughness. - Chryse/Acidalia Planitia, where phyllosilicates, hydrated minerals and sulfates can be found. - The region that spans the terrains from Sinus Meridiani to Syrtis Major, between 15ºS and 45ºN. This region exhibits a high dust index, and is represented by rougher, heavily cratered terrains in many areas. Within these regions, a more detailed identification of landing sites can be performed by refining the study (top-down approach) using higher-resolution geological and compositional maps (e.g., Mars Express/HRSC-OMEGA and/or MRO/HiRISECRISM) coupled with other parameters and constraints. Such detail work will be reported and the resulting suitable landing sites will be made available to the sciencedriven and success-oriented selection process for future Mars missions such as Exomars. This shall then be confronted with bottom-up approaches consisting in the pre-selection of sites purely based on scientific goals prior to the assessment of their suitability for landing.

Thermokarst, mantling and Late Amazonian Epoch periglacial-revisions in the Argyre region, Mars

NASA Astrophysics Data System (ADS)

Soare, R. J.; Baoini, D.; Conway, S. J.; Dohm, J. M.; Kargel, J. S.

2015-10-01

Thermokarst, mantling and Late Amazonian Epoch periglacial-revisions in the Argyre region, Mars R.J. Soare(1), D. Baioni(2), S.J. Conway (3), J.M. Dohm(4)and J.S. Kargel (5)(1) Geography Department, Dawson College, Montreal, Canada H3Z 1A4 rsoare@dawsoncollege.qc.ca.(2) Dipartimento di Scienze della Terra,della Vita e Ambiente, Università di Urbino "Carlo Bo", Campus SOGESTA, 61029 Urbino (PU) Italy. (3) Department of Physical Sciences, Open University, Milton Keynes, United Kingdom, MK7 6AA. (4) The University Museum, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-, Japan.(5) Department of Hydrology & Water Resources, University of Arizona, Tucson, Arizona, USA 85719.1.Introduction Metre to decametre-deep depressions that are rimless, relatively flat-floored, polygonised and scallop-shaped have been widely observed in Utopia Planitia (UP) [e.g. 1-5] and Malea Planum (MP) [6-8]. Although there is some debate about whether the depressions formed by means of sublimation or evaporation, it is commonly believed that the terrain in which the depressions occur is ice-rich.Moreover, most workers assume that this "ice-richness" is derived of a bi-hemispheric, latitudinally-dependent and atmospherically-precipitated mantle that is metres thick [2,4,6-10].

Fractured Mounds in Elysium Planitia

NASA Image and Video Library

2010-10-15

This observation from NASA Mars Reconnaissance Orbiter shows fractured mounds on the southern edge of Elysium Planitia. The fractures that crisscross their surfaces are probably composed of solidified lava.

Search for the viking 2 landing site.

PubMed

Masursky, H; Crabill, N L

1976-10-01

The search for the landing site of Viking 2 was more extensive than the search for the Viking 1 site. Seven times as much area (4.5 million square kilometers) was examined as for Viking 1. Cydonia (B1) and Capri (C1) sites were examined with the Viking 1 orbiter. The B latitude band (40 degrees to 50 degrees N) was selected before the final midcourse maneuver of Viking 2 because of its high scientific interest (that is, high atmospheric water content, surface temperature, possible near-surface permafrost, and a different geological domain). The Viking 1 orbiter continued photographing the Cydonia (B1) site to search for an area large and smooth enough on which to land (three-sigma ellipse; 100 by 260 kilometers); such an area was not found. The second spacecraft photographed and made infrared measurements in large areas in Arcadia (B2) and Utopia Planitia (B3). Both areas are highly textured, mottled cratered plains with abundant impact craters like Cydonia (B1), but smaller sectors in each area are partially mantled by wind-formed deposits. The thermal inertia, from which the grain size of surface material can be computed, and atmospheric water content were determined from the infrared observations. A region in Utopia Planitia, west of the crater Mie, was selected: the landing took place successfully on 3 September 1976 at 3:58:20 p.m. Pacific Daylight Time, earth received time.

Search for the Viking 2 landing site

USGS Publications Warehouse

Masursky, H.; Crabill, N.L.

1976-01-01

The search for the landing site of Viking 2 was more extensive than the search for the Viking 1 site. Seven times as much area (4.5 million square kilometers) was examined as for Viking 1. Cydonia (B1) and Capri (C1) sites were examined with the Viking 1 orbiter. The B latitude band (40?? to 50??N) was selected before the final midcourse maneuver of Viking 2 because of its high scientific interest (that is, high atmospheric water content, surface temperature, possible near-surface permafrost, and a different geological domain). The Viking 1 orbiter continued photographing the Cydonia (B1) site to search for an area large and smooth enough on which to land (three-sigma ellipse; 100 by 260 kilometers); such an area was not found. The second spacecraft photographed and made infrared measurements in large areas in Arcadia (B2) and Utopia Planitia (B3). Both areas are highly textured, mottled cratered plains with abundant impact craters like Cydonia (B1), but smaller sectors in each area are partially mantled by wind-formed deposits. The thermal inertia, from which the grain size of surface material can be computed, and atmospheric water content were determined from the infrared observations. A region in Utopia Planitia, west of the crater Mie, was selected: the landing took place successfully on 3 September 1976 at 3:58:20 p.m. Pacific Daylight Time, earth received time.

Eridania Planitia - False Color

NASA Image and Video Library

2016-06-22

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows part of Eridania Planitia.

Rationale for a Mars Pathfinder mission to Chryse Planitia and the Viking 1 lander

NASA Technical Reports Server (NTRS)

Craddock, Robert A.

1994-01-01

Presently the landing site for Mars Pathfinder will be constrained to latitudes between 0 deg and 30 deg N to facilitate communication with earth and to allow the lander and rover solar arrays to generate the maximum possible power. The reference elevation of the site must also be below 0 km so that the descent parachute, a Viking derivative, has sufficient time to open and slow the lander to the correct terminal velocity. Although Mars has as much land surface area as the continental crust of the earth, such engineering constraints immediately limit the number of possible landing sites to only three broad areas: Amazonis, Chryse, and Isidis Planitia. Of these, both Chryse and Isidis Planitia stand out as the sites offering the most information to address several broad scientific topics.

Distribution, origin and evolution of hypothesized mud volcanoes, thumbprint terrain, small mounds and giant polygons: Implications for sedimentary processes in the northern lowlands of Mars: Case study from the Acidalia Planitia.

NASA Astrophysics Data System (ADS)

Orgel, Csilla; Hauber, Ernst; van Gasselt, Stephan; Pozzobon, Riccardo; Skinner, James, Jr.

2016-04-01

This study is part of the activities of an ISSI International Team, which intends to produce new geomorphological maps of the northern lowlands of Mars along three long traverses across Acidalia, Utopia, and Arcadia Planitiae [1]. This specific study focuses on mounds of different sizes: Large Pitted Mounds (LPM), Thumbprint Terrain (TPT), Small Mounds (SM) as well as km-sized, giant polygons (GP) [2,3]. These landforms were formed on the Vastitas Borealis Formation (VBF) Marginal and Interior Units, which are interpreted as outflow channel deposits or sediments of a hypothesized ocean. The aim of our study is to map the above mentioned features in the northern lowlands and establish a formational history and stratigraphy of landforms using morphological observations and geostatistics in Acidalia Planitia. Our study is based on CTX mosaics (6 m/pixel) and we also used data from HiRISE (0.25 m/px), HRSC (images >10 m/px, HRSC- derived Digital Elevation Models [DEM], grid size 50-200 m), MOLA DEM (~460 m/px), and THEMIS Nighttime IR (~100 m/px). The TPT appears north of about 30°N in the termination zones of the Chryse outflow channels and shows a transition zone with the LPMs at around 36°N in Acidalia Planitia. North of 39°N, only LPM can be observed. LPM are typically surrounded by topographic moats. Sometimes more than 75% of a mound can be covered or embayed by "plain filling material" of varying thickness. The LPM are observed in the same area as large-scale polygon troughs (buried and fresh) associated with circular-shaped small mounds (SM). The SM are located from 34°N to 48°N, completely overlapping the area of LPM and partly the TPT. These features are randomly distributed, but commonly arranged in clusters. Their domical shape with the central pit shows morphological resemblance with the LPM. These features characterize the area from 35 N° to 61 N° and completely disappear in the Acidalia Colles region. The mapping results show a morphological transition zone of the TPT into the LPM in the Acidalia Planitia. It varies by latitude and may be related to the distance from the circum-Chryse outflow channel and the thickening of sediments towards Acidalia Planitia. We find observational evidence for complete or partial sedimentary burial of LPM as well as polygon troughs by a viscous flow material. This material shows flow fronts, suggesting an emplacement by multiple viscous processes [4,5]. We established a new approach of the detailed sequence of the origin of the main four landforms (LPM, TPT, SM, GP) using morphological analysis and geostatistics in combining the results of the previous studies [4,5]. References: [1] Ramsdale, J. et al. (2015) 46th LPSC, Abstract # 1339. [2] Frey, H. and Jarosewich, M. (1982) J. Geophys. Res. 87, B12, 9867-9879. [3] Oehler, D.Z. and Allen, C.C. (2010) Icarus 208, 636-657. [4] Skinner et al. (2008) XXXIX LPSC, Abstract # 2418. [5] Salvatore, M. R. and Christensen, P. R. (2014) JGR Planets, doi: 10.1002/2014JE004682.

Lunar and Planetary Science XXXV: Mars Geophysics

NASA Technical Reports Server (NTRS)

2004-01-01

The titles in this section include: 1) An Extraordinary Magnetic Field Map of Mars; 2) Mapping Weak Crustal Magnetic Fields on Mars with Electron Reflectometry; 3) Analytic Signal in the Interpretation of Mars Southern Highlands Magnetic Field; 4) Modeling of Major Martian Magnetic Anomalies: Further Evidence for Polar Reorientations During the Noachian; 5) An Improved Model of the Crustal Structure of Mars; 6) Geologic Evolution of the Martian Dichotomy and Plains Magnetization in the Ismenius Area of Mars; 7) Relaxation of the Martian Crustal Dichotomy Boundary in the Ismenius Region; 8) Localized Tharsis Loading on Mars: Testing the Membrane Surface Hypothesis; 9) Thermal Stresses and Tharsis Loading: Implications for Wrinkle Ridge Formation on Mars; 10) What Can be Learned about the Martian Lithosphere from Gravity and Topography Data? 11) A Gravity Analysis of the Subsurface Structure of the Utopia Impact Basin; 12) Mechanics of Utopia Basin on Mars; 13) Burying the 'Buried Channels' on Mars: An Alternative Explanation.

Evidence for Basinwide Mud Volcanism in Acidalia Planitia, Mars

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Allen, Carlton C.

2010-01-01

High-albedo mounds in Acidalia Planitia occur in enormous numbers. They have been variously interpreted as pseudocraters, cinder cones, tuff cones, pingos, ice disintegration features, or mud volcanoes. Our work uses regional mapping, basin analysis, and new data from the Context Camera (CTX), High Resolution Imaging Science Experiment (HiRISE), and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) to re-assess the origin and significance of these structures.

Turbulent Lava Flow in Mars Athabasca Valles

NASA Image and Video Library

2010-01-11

This combination of images, taken by NASA Mars Reconnaissance Orbiter, helped researchers analyze the youngest flood lava on Mars, which is in Athabasca Valles, in the Elysium Planitia region of equatorial Mars.

Evidence of mud volcanism rooted in gas hydrate-rich cryosphere linking surface and subsurface for the search for life on Mars

NASA Astrophysics Data System (ADS)

De Toffoli, Barbara; Pozzobon, Riccardo; Mazzarini, Francesco; Massironi, Matteo; Cremonese, Gabriele

2017-04-01

We mapped around 6000 mounds in three different portions of the Martian surface on an average area of about 90.000 Km2 for each region. The study areas are located in Hellas basin, Utopia basin and a portion of the Northern Plains lying north of Arabia Terra, between Acidalia and Utopia Planitia. The aim of the study was to understand the nature of the observed features, particularly if they could be interpreted as mud volcanoes or not, and improve our knowledge about the Martian mound fields origin. The analysis of Context Camera (onboard Mars Reconnaissance Orbiter) images showed circular, elliptical and coalescent mounds with central and/or distal pits and flow features such as concentric annular lobes around the source pits and apron-like extensions. We produced DTMs and then high-to-diameter morphometric analysis on two groups of mounds located in Utopia and Hellas basins to enhance the geomorphological observations. We inferred, by means of cluster and fractal analyses, the thickness of the medium cracked by connected fractures and, consequently, the depths of reservoirs that fed the mounds. We found that the fields, which are seated at different latitudes, has been fed, at least partially, by reservoirs located at the base of the gas hydrate stability zone according to Clifford et al., 2010. This evidence produces a meaningful relationship between the clathrates distribution underneath the Martian surface and the occurrence of mound fields on the surface leading to the assumption that the involvement of water, ostensibly as a result of gas hydrate dissociation, plays a key role in the subsurface processes that potentially worked as triggers. These outcomes corroborate the hypothesis that the mapped mounds are actually mud volcanoes and make these structures outstanding targets for astrobiology and habitability studies. In fact, mud volcanoes, extruding material from depths that are still not affordable by our present-day instrumentations, could have sampled and brought to the surface with the sediments a putative extinct or extant deep biosphere. In conclusion, on the base of this study, emerged that: (i) mud volcanoes are the best terrestrial analogs for the considered Martian mounds, (ii) there is a recurrent specific subsurface environment where the phenomenon may be triggered and it is the base of gas hydrate-rich cryosphere for all the study areas and (iii) mud volcanism seems to be, at least partially, a geologically recent event in terms of planet thermal evolution timespan. In light of these results, the CaSSIS camera, onboard the Trace Gas Orbiter ExoMARS mission, will provide new images of these features to improve and widen the understanding of the mechanisms that lie behind this phenomenon.

Southern rim of Isidis Planitia basin

NASA Image and Video Library

2002-05-21

This scene from NASA Mars Odyssey shows the contrasting morphologies of the relatively rough highland terrain in the lower portion of the image and the relatively smooth materials at top of the southern rim of the Isidis Planitia basin.

Patches of Remnant Frost/Snow on Crater Rim in Northern Summer

NASA Technical Reports Server (NTRS)

1999-01-01

March 1999--it is summer in the martian northern hemisphere, yet patches of frost or snow persist in some areas of the northern plains. Winter ended eight months earlier, in July 1998. Recently, the Mars Orbiter Camera (MOC) passed over a relatively small impact crater located at latitude 68oN (on the Vastitas Borealis plain, north of Utopia Planitia) and took the picture seen at the left, above. The curved crater rims are visible in the upper and lower quarters of the image, and the crater floor is visible at the center right.

The picture on the right is a magnified view of the crater rim area outlined by a white box in the image on the left. The bright patches are snow or frost left over from the martian winter. These snowfields are so small that a human could walk across one of them in a matter of minutes--or perhaps sled down the small, sloping patch that is seen in a shadowed area near the lower left.

In winter, the entire scene shown here would be covered by frost. The long strip at the left covers an area 3 km (1.9 mi) wide by 26 km (16 mi) long. The expanded view on the right covers an area 2.9 km (1.8 mi) by 5.3 km (3.3 mi). Illumination is from the upper right.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Subsurface Structure and the Stress State of the Utopia Basin, Mars

NASA Astrophysics Data System (ADS)

Searls, M. L.; Phillips, R. J.

2005-12-01

A great deal of work has been done in determining the resurfacing history of the northern lowlands; however, most of the previous research has focused on the depth and characteristics of the Hesperian and Amazonian plains units that cover an older, heavily cratered Noachian surface (e.g. Tanaka et. al. 2003). An analysis of the amount and density of fill within the Utopia Basin could provide valuable insight to the depositional environment of the northern lowlands during the earliest epoch of martian history. In the present study we use the topography and gravity data from recent Mars' missions to analyze the subsurface structure of the Utopia basin, focusing on the volume and density of fill that causes the shallowness of the basin. Using the assumption that the initial isostatic state of Utopia was similar to that of the Hellas basin allows us to construct a model for Utopia that facilitates investigation of its interior configuration. Based on the spherical harmonic, thin-shell elastic model of Banerdt (1986), we developed a system of equations that allows us to solve for the original basin shape, the amount of fill within Utopia basin, the amount of flexure due to the fill material, the total vertical load and the horizontal load potential. The presence of quasi-circular depressions within the Utopia basin (Frey 2004) indicates that the majority of the material within Utopia was deposited early in the Noachian when the elastic lithosphere of Mars was (presumably) relatively thin (<50 km). Given this constraint along with constraints placed on the system due to the pre-fill isostatic assumption, we can place a lower bound on the density of the fill within Utopia basin of 2800 kg/m3. This indicates that the amount of fill within the Utopia basin is >15 km, with a corresponding lithospheric flexure/membrane deformation of >14 km. The high density obtained for the fill requires that it contain a large igneous component, the source of which is problematic. Relaxing the isostatic assumption to a reasonable degree perturbs the density bound only slightly. This thin-shell model also allows us to calculate the stress field due to the flexure/membrane strains. The stress results show that the circumferential and radial tectonic features seen in the Utopia region (Thomson and Head 2001) are not due solely to deformation of the elastic lithosphere, so the tectonic features observed are the result, at least in part, of processes that occur within the load itself.

Amazonis Planitia yardangs

NASA Image and Video Library

2002-11-26

This wind-swept region of Amazonis Planitia, imaged here by NASA Mars Odyssey spacecraft, has been so uniformly dissected into yardangs that only two craters provide any indication that other processes have ever been active on the surface. http://photojournal.jpl.nasa.gov/catalog/PIA04010

Geologic Map of MTM -40277, -45277, -40272, and -45272 Quadrangles, Eastern Hellas Planitia Region of Mars

USGS Publications Warehouse

Bleamaster, Leslie F.; Crown, David A.

2010-01-01

Hellas Planitia comprises the floor deposits of the Hellas basin, more than 2,000 km across and 8 km deep, which is located in the southern hemisphere's cratered highlands and is the largest well-preserved impact structure on the Martian surface. The circum-Hellas highlands represent a significant percentage of the southern hemisphere of Mars and have served as a locus for volcanic and sedimentary activity throughout Martian geologic time. Hellas basin topography has had a long-lasting influence, acting as Mars' deepest and second largest depositional sink, as a source for global dust storms, and as a forcing agent on southern hemisphere atmospheric circulation. The region lies in the Martian mid-latitude zone where geomorphic indicators of past, and possibly contemporary, ground ice are prominent. The highlands north of the basin show concentrations of Noachian valley networks, and those to the east show prominent lobate debris aprons that are considered to be geomorphic indicators of ground ice. Several studies have proposed that Hellas itself was the site of extensive glacial and lacustrine activity. Recent analyses of mineralogical information from Mars Express' OMEGA (Observatoire pour la Mineralogie, l'Eau les Glaces et l'Activite) and Mars Reconnaissance Orbiter's CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) reveal outcrops of hydrated phyllosilicates in the region, strengthening an already strong case for past aqueous activity in and around Hellas basin. Our mapping and evaluation of landforms and materials of the Hellas region from basin rim to floor provides further insight into Martian global climate regimes and into the abundance, distribution, and flux of volatiles through history. Mars Transverse Mercator (MTM) quadrangles -40277, -45277, -45272, and -40272 (lat 37.5 degrees S.-47.5 degrees S., long 270 degrees W.-280 degrees W.) cover the eastern portion of the Hellas basin including the boundary between its floor and rim, the distal portions of Dao and Harmakhis Valles, and the deposits of eastern Hellas Planitia. The geologic mapping, at 1:1,000,000-scale from Viking Orbiter, Thermal Emission Imaging System (THEMIS) infrared (IR) and visible (VIS) wavelength, and Mars Orbiter Camera (MOC) narrow-angle images, combined with Mars Orbiter Laser Altimeter (MOLA) topographic data, characterizes the geologic materials and processes that have shaped this region. In particular, the mapping helps to evaluate landforms and deposits resulting from modification of highland terrains by volatile-driven degradation. This mapping study builds on previous mapping in Hellas Planitia and to the east and facilitates comparisons between the geologic history of the east rim, the remainder of the rim, and Hellas Planitia. Specific objectives of our mapping are (1) to reconstruct fluvial systems that dissect the Hellas rim, (2) to characterize the extensions of Dao and Harmakhis Valles onto the basin floor and to identify, if present, sediments these canyons contributed to Hellas Planitia from the rim, and (3) to investigate the mode of origin, age, and history of modification of the boundary between the east rim and Hellas Planitia.

Eroded Scallops with Layers

NASA Image and Video Library

2017-01-09

The western Utopia Planitia in the Northern mid-latitudes of Mars is marked by a peculiar type of depression with scalloped edges and by a network of polygonal fractures. The scalloped depressions are typical features; a smooth layered terrain located between 40 and 60 degrees in both hemispheres. Scalloped depressions probably form by removal of ice-rich subsurface material by sublimation (ice transforming directly from a solid to a gaseous state), a process that may still be active today. Isolated scalloped depressions generally have a steep pole-facing scarp and a gentler equator-facing slope. This asymmetry is interpreted as being the result of difference in solar heating. Scalloped depressions may coalesce, leading to the formation of large areas of pitted terrain. The polygonal pattern of fractures resembles permafrost polygons that form in terrestrial polar and high alpine regions by seasonal-to-annual contraction of the permafrost (permanently frozen ground). On Earth, such polygons indicate the presence of ground ice. These landforms most likely show that sub-surface ice is present or has been present geologically recently at these latitudes, and they may slowly be continuing their development at the present time. http://photojournal.jpl.nasa.gov/catalog/PIA13485

The Martian, Part 1: Acidalia Planitia

NASA Image and Video Library

2015-10-12

All this week, the THEMIS Image of the Day is following on the real Mars the path taken by fictional astronaut Mark Watney, stranded on the Red Planet in the book and movie, The Martian. Today's image shows a small portion of Acidalia Planitia, a largely flat plain that is part of Mars' vast northern lowlands. Scientists are debating the likelihood that the northern plains once contained a large ocean or other bodies of water, probably ice-covered. In the story, Acidalia Planitia is the landing site for a human expedition to Mars. After a dust storm damages the crew habitat and apparently kills Watney, the remaining crew abandon the expedition and leave for Earth. Watney however is still alive, and to save himself he must journey nearly 4,000 kilometers (2,500 miles) east to Schiaparelli Crater, where a rescue rocket awaits. Orbit Number: 27733 Latitude: 31.218 Longitude: 332.195 Instrument: VIS Captured: 2008-03-15 20:24 http://photojournal.jpl.nasa.gov/catalog/PIA19796

Beagle 2: Seeking the Signatures of Life on Mars

NASA Technical Reports Server (NTRS)

Gibson, Everett K., Jr.; Pillinger, Colin T.; Wright, Ian P.; Morse, Andy; Stewart, Jenny; Morgan, G.; Praine, Ian; Leigh, Dennis; Sims, Mark R.; Pullan, Derek

2003-01-01

Beagle 2 is a 60 kg probe (with a 30 kg lander) developed in the United Kingdom for inclusion on the European Space Agency s 2003 Mars Express. Beagle 2 will deliver to the Martian surface a payload which consists of a high percentage of science instruments to landed spacecraft mass. Beagle 2 will be launched in June 2003 with Mars Express on a Soyuz-Fregat rocket from the Baikonur Cosmodrome in Kazakhstan. Beagle 2 will land on Mars in December 2003 in Isidis Planitia (approx. 11.5 deg.N and 275 deg.W), a large sedimentary basin that overlies the boundary between ancient highlands and northern plains. Isidis Planitia, the third largest basin on Mars, which is possibly filled with sediment deposited at the bottom of long-standing lakes or seas, offers an ideal environment for preserving traces of life. Beagle 2 is completed and undergoing integration with the Mars Express orbiter prior to launch.

Buried Craters In Isidis Planitia, Mars

NASA Astrophysics Data System (ADS)

Seabrook, A. M.; Rothery, D. A.; Wallis, D.; Bridges, J. C.; Wright, I. P.

We have produced a topographic map of Isidis Planitia, which includes the Beagle 2 landing site, using interpolated Mars Orbiter Laser Altimeter (MOLA) data from the Mars Global Surveyor (MGS) spacecraft currently orbiting Mars. MOLA data have a vertical precision of 37.5 cm, a footprint size of 130 m, an along-track shot spacing of 330 m, and an across-track spacing that is variable and may be several kilometres. This has revealed subtle topographic detail within the relatively smooth basin of Isidis Planitia. Analysis of this map shows apparent wrinkle ridges that could be the volcanic basement to the basin and also several circular depressions with diameters of several to tens of kilometres which we interpreted as buried impact craters, comparable to the so-called stealth craters recognised elsewhere in the northern lowlands of Mars[1]. Stealth craters are considered to be impact craters subjected to erosion and/or burial. Some of these features in Isidis have depressions that are on the order of tens metres lower than their rims and are very smooth, and so are often not visible in MGS Mars Orbiter Camera (MOC) or Viking images of the basin. The Isidis stealth craters are not restricted to the Hesperian Vastitas Borealis formations like those detected elsewhere in the northern lowlands by Kreslavsky and Head [1], but are also found in a younger Amazonian smooth plains unit. It is generally believed that Isidis Planitia has undergone one or more episodes of sedi- ment deposition, and so these buried craters most likely lie on an earlier surface, which could be the postulated volcanic basement to the basin. Analysis of the buried craters may give some understanding of the thickness, frequencies and ages of sedimentation episodes within the basin. This information will be important in developing a context in which information from the Beagle 2 lander can be analysed when it arrives on Mars in December 2003. [1] Kreslavsky M. A. and Head J. W. (2001) LPS XXXII

Mars Landing + 50 Years: Repurposing the First Viking Landing Site on Chryse Planitia as an Exploration Zone for Automated Infrastructure Construction

NASA Astrophysics Data System (ADS)

Farrell, K. W.

2015-10-01

The proposed Chryse Planitia EZ centered near the VL-1 landing site has evidence for adequate water ice, silica, and load-bearing bedrock surface resources to utilize as infrastructure for long-term missions to support humans.

Geology of Chryse Planitia

NASA Technical Reports Server (NTRS)

Greeley, R.; Theilig, E.; Guest, J. E.; Carr, M. H.; Masursky, H.; Cutts, J. A.

1977-01-01

Chryse Planitia, the site of the first successful landing on Mars by Viking 1, is an asymmetrical basin, centered at 45 deg W and 24 deg N, about 2000 km northeast of Valles Marineris. High-resolution Viking orbiter images show Chryse Planitia to be much more complex than had been suspected from Mariner 9 images. On the basis of a study of the Viking pictures it is concluded that the geological history of Chryse Planitia involves a complex sequence of impact cratering, mantling by extensive deposits of unknown origin, redistribution of mantling and crater materials by erosion and deposition with concurrent eruptions of flood-type basalts, and aeolian activity.

Visualization of Buried Marte Vallis Channels

NASA Image and Video Library

2013-03-07

This illustration schematically shows where the Shallow Radar instrument on NASA Mars Reconnaissance Orbiter detected flood channels that had been buried by lava flows in the Elysium Planitia region of Mars.

Scaly-skinned Mars

NASA Image and Video Library

2002-12-20

The style of erosion along the highlands-lowlands boundary of southern Elysium Planitia has produced a strange pattern of troughs that look like the skin of a reptile, as seen in this image from NASA Mars Odyssey spacecraft.

Tempe Terra

NASA Image and Video Library

2002-12-18

This image from NASA Mars Odyssey is of a region of Mars called Tempe Terra, which is located between the topographically high Tharsis Region and Acidalia Planitia, a large low albedo region of in the Martian northern hemisphere.

Search for organic and volatile inorganic compounds in two surface samples from the chryse planitia region of Mars.

PubMed

Biemann, K; Oro, J; Toulmin, P; Orgel, L E; Nier, A O; Anderson, D M; Simmonds, P G; Flory, D; Diaz, A V; Rushneck, D R; Biller, J A

1976-10-01

Two surface samples collected from the Chryse Planitia region of Mars were heated to temperatures up to 500 degrees C, and the volatiles that they evolved were analyzed with a gas chromatograph-mass spectrometer. Only water and carbon dioxide were detected. This implies that organic compounds have not accumulated to the extent that individual components could be detected at levels of a few parts in 10(9) by weight in our samples. Proposed mechanisms for the accumulation and destruction of organic compounds are discussed in the light of this limit.

Search for organic and volatile inorganic compounds in two surface samples from the Chryse Planitia region of Mars

NASA Technical Reports Server (NTRS)

Biemann, K.; Oro, J.; Toulmin, P., III; Orgel, L. E.; Nier, A. O.; Anderson, D. M.; Flory, D.; Diaz, A. V.; Rushneck, D. R.; Simmonds, P. G.

1976-01-01

Two surface samples collected from the Chryse Planitia region of Mars were heated to temperatures up to 500 C, and the volatiles that they evolved were analyzed with a gas chromatograph-mass spectrometer. Only water and carbon dioxide were detected. This implies that organic compounds have not accumulated to the extent that individual components could be detected at levels of a few parts per billion by weight in the samples. Proposed mechanisms for the accumulation and destruction of organic compounds are discussed in the light of this limit.

Search for organic and volatile inorganic compounds in two surface samples from the chryse planitia region of Mars

USGS Publications Warehouse

Biemann, K.; Oro, John; Toulmin, P.; Orgel, Leslie E.; Nier, A.O.; Anderson, D.M.; Simmonds, P.G.; Flory, D.; Diaz, A.V.; Rushneck, D.R.; Biller, J.A.

1976-01-01

Two surface samples collected from the Chryse Planitia region of Mars were heated to temperatures up to 500??C, and the volatiles that they evolved were analyzed with a gas chromatograph-mass spectrometer. Only water and carbon dioxide were detected. This implies that organic compounds have not accumulated to the extent that individual components could be detected at levels of a few parts in 109 by weight in our samples. Proposed mechanisms for the accumulation and destruction of organic compounds are discussed in the light of this limit.

Sedimentary geomorphology of the Mars Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

Rice, James W., Jr.; Parker, Timothy Jay

1997-01-01

The first landing on Mars in over 20 years will take place July 4, 1997, near te mouth of the Ares Vallis outflow channel located in southeastern Chryse Planitia. Mars Pathfinder, unlike Viking 1, is expected to land on a surface that has a distinct and unambiguous fluvial signature.

Mars at Ls 341o: Acidalia/Mare Erythraeum

NASA Technical Reports Server (NTRS)

2005-01-01

13 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a banded surface in Argyre Planitia, the second largest impact basin in the martian southern hemisphere. The bands are the erosional expression of layered, perhaps sedimentary, rock.

Season: Northern Winter/Southern Summer

Viking Lander 2 Anniversary

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site]

This portion of a daytime IR image covers the Viking 2 landing site (shown with the X). The second landing on Mars took place September 3, 1976 in Utopia Planitia. The exact location of Lander 2 is not as well established as Lander 1 because there were no clearly identifiable features in the lander images as there were for the site of Lander 1. The Utopia landing site region contains pedestal craters, shallow swales and gentle ridges. The crater Goldstone was named in honor of the Tracking Station in the desert of California. The two Viking Landers operated for over 6 years (nearly four martian years) after landing. This one band IR (band 9 at 12.6 microns) image shows bright and dark textures, which are primarily due to differences in the abundance of rocks on the surface. The relatively cool (dark) regions during the day are rocky or indurated materials, fine sand and dust are warmer (bright). Many of the temperature variations are due to slope effects, with sun-facing slopes warmer than shaded slopes. The dark rings around several of the craters are due to the presence of rocky (cool) material ejected from the crater. These rocks are well below the resolution of any existing Mars camera, but THEMIS can detect the temperature variations they produce. Daytime temperature variations are produced by a combination of topographic (solar heating) and thermophysical (thermal inertia and albedo) effects. Due to topographic heating the surface morphologies seen in THEMIS daytime IR images are similar to those seen in previous imagery and MOLA topography.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Acidalia Planitia

NASA Image and Video Library

2002-12-18

Much of the northern lowlands of Mars are thought to be relatively young volcanic flows with varying amounts of windblown dust cover. The lack of impact craters in this image from NASA Mars Odyssey spacecraft indicate the young age of the surface.

A Failed Utopia in Marcela Del Río's "Proceso a Faubritten"

ERIC Educational Resources Information Center

Manickam, Samuel

2014-01-01

In Marcela del Río's science fiction novel "Proceso a Faubritten," utopia comes in the form of eternal life for all of humanity, thanks to Dr. Alexander Faubritten's "Bomba L." This polyphonic work includes diaries by Faubritten and his Mexican lover, María Corona. In my analysis of these two diaries, I will show how…

End of Lethe Vallis

NASA Image and Video Library

2010-11-15

This image from NASA Mars Reconnaissance Orbiter shows the funnel-shaped terminus of Lethe Vallis, a winding channel in the Elysium Planitia region of Mars; the floor is covered in solidified lava and blanketed by a thin layer of light-toned dust.

Discovery of columnar jointing on Mars

USGS Publications Warehouse

Milazzo, M.P.; Keszthelyi, L.P.; Jaeger, W.L.; Rosiek, M.; Mattson, S.; Verba, C.; Beyer, R.A.; Geissler, P.E.; McEwen, A.S.

2009-01-01

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 obliterated by the impact event were similarly jointed. We also see columns in the walls of other fresh craters in the nearby volcanic plains of Elysium Planitia-Amazonis Planitia, which include Marte Vallis, and in a well-preserved crater in northeast Hellas. ?? 2009 The Geological Society of America.

Measuring the Pulse of Mars

NASA Image and Video Library

2018-01-25

Elysium Planitia, a flat-smooth plain just north of the equator makes for the perfect location from which to study the deep Martian interior. Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, is designed to study the deep interior of Mars. The mission seeks the fingerprints of the processes that formed the rocky planets of the solar system. Its landing site, Elysium Planitia, was picked from 22 candidates, and is centered at about 4.5 degrees north latitude and 135.9 degrees east longitude; about 373 miles (600 kilometers) from Curiosity's landing site, Gale Crater. The locations of other Mars landers and rovers are labeled. InSight's scientific success and safe landing depends on landing in a relatively flat area, with an elevation low enough to have sufficient atmosphere above the site for a safe landing. It also depends on landing in an area where rocks are few in number. Elysium Planitia has just the right surface for the instruments to be able to probe the deep interior, and its proximity to the equator ensures that the solar-powered lander is exposed to plenty of sunlight. https://photojournal.jpl.nasa.gov/catalog/PIA22232

1st Manned Lunar Landing and 1st Robotic Mars Landing Commemorative Release: Viking 1 Landing Site in Chryse Planitia - Infrared Image

NASA Image and Video Library

2002-07-22

This NASA Mars Odyssey image of NASA Viking 1 landing site was taken to commemorate the anniversaries of NASA Apollo 11 landing on the Moon and Viking 1 landing on Mars -- July 20, 1969 and July 20, 1976, respectively.

1st Manned Lunar Landing and 1st Robotic Mars Landing Commemorative Release: Viking 1 Landing Site in Chryse Planitia - Visible Image

NASA Image and Video Library

2002-07-22

NASA Viking 1 landing site is shown in this commemorative image from NASA Mars Odyssey spacecraft to celebrate the July 20, 1969 and 1976 anniversaries of NASA Apollo 11 and Viking 1 landings on the Moon and Mars, respectively.

Geomorphological assemblages in Arcadia Planitia: clues about a global scale event?

NASA Astrophysics Data System (ADS)

De Toffoli, B.; Pozzobon, R.; Mazzarini, F.; Massironi, M.; Cremonese, G.

2017-09-01

Mound-like features have been detected in the Arcadia Planitia region in the Northern hemisphere of Mars. Particularly, we investigated landforms that, due to their morphological characteristics and surface distribution, could be interpreted as water related features, such as mud volcanoes or spring vents. Additionally, the collected evidence suggests that a putative single phenomenon acted as trigger to such resurgences on global scale.

SHARAD Investigation of the Interaction Between Volcanism and Deep Water Release in Elysium Planitia, Mars

NASA Astrophysics Data System (ADS)

Morgan, G. A.; Campbell, B. A.; Carter, L. M.; Plaut, J. J.

2011-12-01

Situated between the equator and 12°N and extending from 130° to 180°E, Elysium Planitia is considered to be the youngest volcanic plain on Mars. Recent crater counts on individual lava units argue for multiple phases of activity over the last 230 Myrs, with the most recent volcanic features dating to just ~2 Ma. The region also contains the youngest outflow channels on the planet. Multiple channel systems which are present across the region are interpreted to have been carved by the release of deep ground water (>1 km) from the broadly east-west trending Cerberus Fossae graben system. Elysium Planitia is therefore a region of high scientific interest, as it represents an ideal site to investigate the interaction of lava and water both below and on the surface of Mars. Extensive geologic mapping of Elysium Planitia has provided detailed information concerning the stratigraphy of the major volcanic units in addition to the classification of other landforms attributed to volcanic (e.g. small shields), fluvial (e.g. outflow channels) and aeolian (e.g. yardangs) activity. Orbital sounding radar provides a means to take this work to the next level through the mapping of buried surfaces associated with a contrast in dielectric permittivity and thus can be used to investigate the 3-D structure of the subsurface. Previous studies using the SHARAD radar sounder onboard the Mars Reconnaissance Orbiter have identified multiple subsurface reflectors below the plains of Elysium Planitia. We will present our investigation of SHARAD data covering the eastern portion of this region of Mars - an area that includes the upstream reaches of Marte Vallis and the eastern extent of Cerberus Fossae. Our subsurface mapping shows remarkable correlations with published geologic maps produced using visible orbital datasets. These similarities allow us to use SHARAD data to make estimates of the average permittivity values and imply density measurements of the volcanic units. We will present these estimates and compare them to values derived over other young volcanic regions on Mars. Sounding radar provides the only type of orbital instrument to derive bulk estimates of geochemical properties of martian volcanic materials. Additionally we have identified the original fluvial eroded bed of Marte Vallis, prior to burial by younger lava flows. Through the mapping of the associated fluvial features we are able to tie the origin of Marte Vallis to Cerberus Fossae and provide further support for the recent (Late Amazonian) deep subsurface release of water on the surface of Mars. Our work will provide valuable constraints on the influence of recent volcanism on martian subsurface reservoirs of water.

An Investigation of the Hypotheses for Formation of the Platy-Ridged Terrain in Elysium Planitia, Mars

NASA Astrophysics Data System (ADS)

Yue, Z.; Gou, S.; Michael, G.; Di, K.; Xie, H.; Gong, H.; Shao, Y.

2017-07-01

The origin of the platy-ridged-polygonized (PRP) terrains on Martian surface has long been debated. The terrain has generally been classified as water, pack ice, or basalt lava related flow. The crater counting results of the PRP terrains suggest they are geologically very young; therefore, they are significant in understanding the recent evolution of Mars. This work evaluated the current hypotheses through detailed analysis of the distribution and microtopographies with the High Resolution Imaging Science Experiment (HiRISE) images for the PRP terrains in Elysium Planitia, Mars. Quantitative measurements and statistics of the typical features of the PRP terrains were also made. In addition, we also found an analog site in Tarim Basin in Xinjiang, China. Our results suggest that mud flow is responsible for the formation of the PRP terrains on the Mars surface, although the hypothesis of low-viscosity basalt lava floods cannot be completely excluded. This finding implies that a regional environment suitable for liquid water may have existed in recent geologic time, which has great importance for future Mars scientific exploration.

Exposed Ice in the Northern Mid-Latitudes of Mars

NASA Technical Reports Server (NTRS)

Allen, Carlton C.

2007-01-01

Ice-Rich Layer: Polygonal features with dimensions of approximately 100 meters, bounded by cracks, are commonly observed on the martian northern plains. These features are generally attributed to thermal cracking of ice-rich sediments, in direct analogy to polygons in terrestrial polar regions. We mapped polygons in the northern mid-latitudes (30 to 65 N) using MOC and HiRISE images. Polygons are scattered across the northern plains, with a particular concentration in western Utopia Planitia. This region largely overlaps the Late Amazonian Astapus Colles unit, characterized by polygonal terrain and nested pits consistent with periglacial and thermokarst origins. Bright and Dark Polygonal Cracks: An examination of all MOC images (1997 through 2003) covering the study area demonstrated that, at latitudes of 55 to 65 N, most of the imaged polygons show bright bounding cracks. We interpret these bright cracks as exposed ice. Between 40 and 55 N, most of the imaged polygons show dark bounding cracks. These are interpreted as polygons from which the exposed ice has been removed by sublimation. The long-term stability limit for exposed ice, even in deep cracks, apparently lies near 55 N. Bright and Dark Spots: Many HiRISE and MOC frames showing polygons in the northern plains also show small numbers of bright and dark spots, particularly in western Utopia Planitia. Many of the spots are closely associated with collapse features suggestive of thermokarst. The spots range from tens to approximately 100 meters in diameter. The bright spots are interpreted as exposed ice, due to their prevalence on terrain mapped as ice rich. The dark spots are interpreted as former bright spots, which have darkened as the exposed ice is lost by sublimation. The bright spots may be the martian equivalents of pingos, ice-cored mounds found in periglacial regions on Earth. Terrestrial pingos from which the ice core has melted often collapse to form depressions similar to the martian dark spots. Future Observations: The SHARAD radar should be able to confirm the presence and measure the depth of the interpreted ice-rich layer that forms the Astapus Colles unit. If this layer is confirmed it will strengthen the interpretation of bright polygon cracks and bright spots as exposed ice. HiRISE images of the northern plains are showing unprecedented details of the polygonal cracks. Future HiRISE images that include bright spots, compared to MOC images taken years earlier, will illustrate the temporal stability of the spots. The CRISM spectrometer, with multiple spectral bands and a spatial resolution around 20 meters, should allow mineralogical identification of the material exposed in the polygonal bounding cracks and in the bright spots.

Latent outflow activity for western Tharsis, Mars: Significant flood record exposed

USGS Publications Warehouse

Dohm, J.M.; Anderson, R.C.; Baker, V.R.; Ferris, J.C.; Rudd, L.P.; Hare, T.M.; Rice, J. W.; Casavant, R.R.; Strom, R.G.; Zimbelman, J.R.; Scott, D.H.

2001-01-01

Observations permitted by the newly acquired Mars Observer Laser Altimeter data have revealed a system of gigantic valleys northwest of the huge Martian shield volcano, Arsia Mons, in the western hemisphere of Mars (northwestern slope valleys (NSVs)). These features, which generally correspond spatially to gravity lows, are obscured by veneers of materials including volcanic lava flows, air fall deposits, and eolian materials. Geologic investigations of the Tharsis region suggest that the system of gigantic valleys predates the construction of Arsia Mons and its extensive associated lava flows of mainly late Hesperian and Amazonian age and coincides stratigraphically with the early development of the outflow channels that debouch into Chryse Planitia. Similar to the previously identified outflow channels, which issued tremendous volumes of water into topographic lows such as Chryse Planitia, the NSVs potentially represent flooding of immense magnitude and, as such, a source of water for a northern plains ocean.

Variations in Crustal Structure, Lithospheric Flexural Strength, and Isostatic Compensation Mechanisms of Mars

NASA Astrophysics Data System (ADS)

Ding, M.; Lin, J.; Zuber, M. T.

2014-12-01

We analyze gravity and topography of Mars to investigate the spatial variations in crustal thickness, lithospheric strength, and mechanisms of support of prominent topographic features on Mars. The latest gravity model JGMRO110c (released in 2012) from the Mars Reconnaissance Orbiter mission has a spatial block size resolution of ~97 km (corresponding to degree-110), enabling us to resolve crustal structures at higher spatial resolution than those determined from previous degree-80 and 85 gravity models [Zuber et al., 2000; McGovern et al., 2002, 2004; Neumann et al., 2004; Belleguic et al., 2005]. Using the latest gravity data, we first inverted for a new version of crustal thickness model of Mars assuming homogeneous crust and mantle densities of 2.9 and 3.5 g/cm3. We calculated "isostatic" topography for the Airy local isostatic compensation mechanism, and "non-isostatic" topography after removing the isostatic part. We find that about 92% of the Martian surface is in relatively isostatic state, indicating either relatively small lithospheric strength and/or small vertical loading. Relatively isostatic regions include the hemispheric dichotomy, Hellas and Argyre Planitia, Noachis and Arabia Terra, and Terra Cimmeria. In contrast, regions with significant amount of non-isostatic topography include the Olympus, Ascraeus, Arsia, Pavonis, Alba, and Elysium Mons, Isidis Planitia and Valles Marineris. Their relatively large "non-isostatc topography" implies relatively strong lithospheric strength and large vertical loading. Spectral analysis of the admittance and correlation relationship between gravity and topography were conducted for the non-isostatic regions using the localized spectra method [Wieczorek and Simons, 2005, 2007] and thin-shell lithospheric flexural approximation [Forsyth, 1985; McGovern et al., 2002, 2004]. The best-fitting models reveal significant variations in the effective lithospheric thickness with the greatest values for the Olympus Mon, Valles Marineris, and Isidis Planitia; reduced values for the Ascraeus, Arsis, and Pavonis Mons; and smallest values for the Alba and Elysium Mons. Our models also suggest that there could be significant sub-surface loading underneath the Olympus, Ascraeus, Arsia, and Pavonis Mons, and Isidis Planitia.

A formational model for the polygonal terrains of Mars: Taking a crack at the genesis of the Martian polygons

NASA Technical Reports Server (NTRS)

Wenrich, M. L.; Christensen, P. R.

1993-01-01

The mechanism for the genesis of the polygonal terrains in Acidalia and Utopia Planitia has long been sought: however, no completely satisfying model was put forth that characterizes the evolution of these complexly patterned terrains. The polygons are roughly hexagonal but some are not entirely enclosed by fractures. These polygonal features range in widths from approximately 5 to 20 km. Several origins were proposed that describe the polygon borders as desiccation cracks, columnar jointing in a cooled lava, or frost-wedge features. These tension-induced cracking hypotheses were addressed by Pechmann, who convincingly disputes these mechanisms of formation based on scale magnitude difficulties and morphology. Pechmann suggests instead that the cracks delineating the 5-20-km-wide polygons on the northern plains of Mars are graben resulting from deep-seated, uniform, horizontal tension. The difficulty with this hypothesis is that no analogous polygonal forms are known to have originated by tectonism on Earth. McGill and Hills propose that the polygonal terrains on Mars resulted from either rapid desiccation of sediments or cooling of volcanics coupled with differential compaction of the material over a buried irregular topographic surface. They suggest that fracturing was enhanced over the areas of positive relief and was suppressed above the topographic lows. McGill and Hills suggest that the spacing of the topographic highs primarily controls the size of the Martian polygons and the physics of the shrinkage process is a secondary concern. Ray et. al. conducted a terrestrial study of patterned ground in periglacial areas of the U.S. to determine the process responsible for polygonal ground formation. They developed a model for polygon formation in which convection of seasonal melt water above a permafrost layer, driven by an unstable density stratification, differentially melts the permafrost interface, causing it to become undulatory.

Mapping Mars' northern plains: origins, evolution and response to climate change - a new overview of recent ice-related landforms in Acidalia Planitia.

NASA Astrophysics Data System (ADS)

Hauber, Ernst; Orgel, Csilla; van Gasselt, Stephan; Reiss, Dennis; Johnsson, Andreas; Ramsdale, Jason; Balme, Matthew; Conway, Susan; Costard, Francois; Gallagher, Colman; Kereszturi, Akos; Platz, Thomas; Séjourné, Antoine; Skinner, James; Swirad, Zuzanna; Łosiak, Anna

2015-04-01

An International Space Science Institute (ISSI) team project has been convened to study the northern plains of Mars. It uses a geomorphological grid-mapping approach to compare ice-related landforms across N-S traverses in the three main basins of the northern plains: Acidalia, Arcadia, and Utopia Planitiae. The main science questions are (i) the distribution of ice-related landforms in the northern plains and their relation to distinct latitude bands or different geological units, (ii) the relationship between the latitude dependent mantle (LDM) and landforms indicative of ground ice, and (iii) the distributions and associations of recent landforms indicative of thaw of ice or snow. We mapped individual landforms across the Acidalia Planitia that may have been formed in association with ice or water in an attempt to determine their extent and identify possible spatial relationships and genetic links between them. Our list includes mantling deposits, small-scale polygons, gullies, viscous flow features, thumbprint terrain (TPT), giant polygons and large pitted mounds (LPM). Our resulting maps show the distribution of specific landforms (no data - absence - presence - dominance) in grid cells with a size of ~20 × 20 km, but allows also for some ambiguity (possible). Preliminary results show that the mantling deposits are ubiquitous and occur basically everywhere between ~43°N and almost the margin of the north polar cap. As their surface may appear smooth if intact, their texture can be difficult to detect at CTX scale. Gullies were observed within a limited latitude range between ~32°N and ~54°N. They predominantly occur in Acidalia and Acidalia Colles, although gullies were found in several impact craters. Small-scale polygons occur between ~60°N to ~70°N in agreement with previous studies. They are predominantly oriented in orthogonal networks in crater interiors, depressions and on plains. Viscous flow features are present only in higher-relief areas of the Acidalia Mensae and Colles. Their morphology is not well pronounced, partially subdued and covered, and most features are restricted to debris aprons distributed circumferentially around small knobs. TPT appears north of about 30°N in the most distal parts of the Chryse outflow channels and shows a transition zone with LPM at around 36°N and it is not observed north of ~39N°. The giant polygons with the LPM have been considered analogous to fluid expulsion features in terrestrial sedimentary basins. They characterize the study area from to 35 N° until 61 N° and completely disappear in the Acidalia Colles region. Grid mapping proved to be an efficient way to map small-scale landforms over wide areas. The distribution of possible ice- and water-related features in Acidalia is clearly latitude- and topography-dependent

Chryse 'Alien Head'

NASA Technical Reports Server (NTRS)

2005-01-01

26 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an impact crater in Chryse Planitia, not too far from the Viking 1 lander site, that to seems to resemble a bug-eyed head. The two odd depressions at the north end of the crater (the 'eyes') may have formed by wind or water erosion. This region has been modified by both processes, with water action occurring in the distant past via floods that poured across western Chryse Planitia from Maja Valles, and wind action common occurrence in more recent history. This crater is located near 22.5oN, 47.9oW. The 150 meter scale bar is about 164 yards long. Sunlight illuminates the scene from the left/lower left.

Geologic map of the MTM 25047 and 20047 quadrangles, central Chryse Planitia/Viking 1 Lander site, Mars

USGS Publications Warehouse

Crumpler, L.S.; Craddock, R.A.; Aubele, J.C.

2001-01-01

This map uses Viking Orbiter image data and Viking 1 Lander image data to evaluate the geologic history of a part of Chryse Planitia, Mars. The map area lies at the termini of the Maja and Kasei Valles outwash channels and includes the site of the Viking 1 Lander. The photomosaic base for these quadrangles was assembled from 98 Viking Orbiter frames comprising 1204 pixels per line and 1056 lines and ranging in resolution from 20 to 200 m/pixel. These orbital image data were supplemented with images of the surface as seen from the Viking 1 Lander, one of only three sites on the martian surface where planetary geologic mapping is assisted by ground truth.

Megafans as Hydrous Environments

NASA Technical Reports Server (NTRS)

Wilkinson, M. Justin; Miller, R. McG.; Allen, C. C.; Kreslavsky, M. H.; Eckardt, F.

2009-01-01

The mesoscale sedimentary environment known as the megafan, is a low-angle, partial cone of fluvial sediment generated where a river enters an unconfined basin where it begins the process of avulsing over wide areas. In shifting to different positions, the river lays down a partial cone of sediment and establishes a characteristic radial pattern of paleo courses. The apparent paucity of sedimentary bodies obviously tied to martian outflow channels may also relate to the difficulty of recognition due to their sheer size and featurelessness. However, the existence of megafans on Mars is being examined now that their ubiquity and characteristics on Earth are better understood. Accordingly we suggest two likely candidates on Mars: Maja Valles fluvial cone and Amazonis Planitia fluvial sedimentary bodies. Two cryptic examples from Amazonis Planitia may be important for understanding subsurface hydrous accumulation. For at least some of its history, discharges from Mangala Valles likely resulted in megafans. Distances from the end of Mangala Valles to the northern (low) margin of the planitia are very large, a fact that has suggested that fluvial emplacement was unlikely. However, the megafan model shows that long megafan radii are indeed feasible. It has been suggested further that discharge from Labou Vallis (8.5S 154.5W) must have led to fluvial sedimentation in the planitia. We suggest that during locally non-lacustrine/ocean phases, this sedimentation would have occurred in the form of megafans. However, the megafan model shows that long megafan radii are indeed feasible. It has been suggested further that discharge from Labou Vallis (8.5S 154.5W) must have led to fluvial sedimentation in the planitia. We suggest that during locally non-lacustrine/ocean phases, this sedimentation would have occurred in the form of megafans. Megafans emanating from Marte, Mangala and Labou valles have probably contributed to hydrous near-subsurface environments--in their distal reaches, i.e. along the northern, eastern and southeastern margins of Amazonis Planitia at various times. Following a new terrestrial analog, we conclude groundwater has at times accumulated preferentially beneath distal slopes of the Maja Valles feature, and along the northern, eastern and southeastern margins of Amazonis Planitia.

Mars on 25 December 2003

NASA Technical Reports Server (NTRS)

2004-01-01

8 January 2004 This is how Mars appeared to the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle system on 25 December 2003, the day that Beagle 2 and Mars Express reached the red planet. The large, dark region just left of center is Syrtis Major, a persistent low albedo terrain known to astronomers for nearly four centuries before the first spacecraft went to Mars. Immediately to the right (east) of Syrtis Major is the somewhat circular plain, Isidis Planitia. Beagle 2 arrived in Isidis Planitia only about 18 minutes before Mars Global Surveyor flew over the region and acquired a portion of this global view. Relative to other global images of Mars acquired by MGS over the past several martian years, the surface features were not as sharp and distinct on 25 December 2003 because of considerable haze kicked up by large dust storms in the western and southern hemispheres during th previous two weeks. The picture is a composite of several MGS MOC red and blue daily global images that have been map-projected and digitally wrapped to a sphere. Although the effect here is minor, inspection of this mosaic shows zones that appear smudged or blurry. The high dust opacity on 25 December impacted MOC's oblique viewing geometry toward the edges of each orbit's daily global mapping image, thus emphasizing the 'blurry' zones between images acquired on successive orbits.

Surface Changes in Chryse Planitia

NASA Technical Reports Server (NTRS)

1979-01-01

At the conclusion of the Viking Continuation Mission (May to November, 1978), all four cameras on the Viking Landers - two on each spacecraft - continued to function normally. During the two and one-half years since the landers touched down on Mars, images totaled 2,255 for Viking Lander 1 and 2,016 for Viking Lander 2. The surface around the landers was completely photographed by the end of 1976; subsequent images acquired during 1977-1978 have concentrated on searching for changes in the scene - changes which can be used to infer both the types of erosive processes which modify the landscape around the landers and the rates at which these processes may occur. The major surface changes have included the water-ice snow seen by Lander 2 during the winter at Utopia Planitia, and a thin dust layer deposited at both sites during the dust storms of 1977. The most recently identified change occurred at Chryse Planitia between VL-1 sols 767 (Sept. 16, 1978) and 771 (Sept. 20, 1978) as seen in the lower photo. Picture at top, selected to show similar lighting conditions, was taken during sol 25 (August 15, 1976). The change (A) appears as a small circle-like formation on the side of a drift in the lee, or downwind, side of Whale Rock. This is believed to have been a small-scale landslide of an unstable dust layer which had accumulated behind the rock. Interpretation of this feature would be difficult without an earlier change (B) near Big Joe, a slump which occurred between sols 74 and 183. The new slump is approximately 25- 35 meters from the lander, and just under a meter across. The slumping probably was initiated by the daily heating and cooling of the surface by solar radiation. More importantly, it is now believed that, based on the repeated occurrence of such slumping features, a dust layer which overlies the surface may in fact be redistributed fairly regularly during periods of high wind activity. There are no obvious indications of fossil slump features, therefore similar features must be destroyed on a regular basis. After the end of February, when Viking operations essentially terminate, Lander 1 will continue preselected observations over a period of possibly up to 10 years, following the instructions stored in its computer memory. Earth commands will be required only to initiate data transmission to Earth. During this time, it is now anticipated that one of the yearly planetwide global dust storms may reach an intensity necessary to shift the dust cover around the lander significantly.

The influence of oceans on Martian volcanism

NASA Technical Reports Server (NTRS)

Mouginis-Mark, Peter

1993-01-01

Geomorphological evidence for episodic oceans on Mars has recently been identified. This idea of large bodies of water on Mars is innovative and controversial compared to the more generally accepted view of a 'dry Mars', but also enables some of the more enigmatic volcanic landforms to be reinterpreted in a self-consistent model. This hypothesis can be used to develop new models for the mode of formation of several volcanic landforms in the W. Tharsis and S.E. Elysium Planitia regions of Mars.

Icy Islands reveal similar volatile behavior on Pluto and Mars

NASA Astrophysics Data System (ADS)

Sori, M.; Bapst, J.; Byrne, S.

2017-12-01

Ice deposits on planetary surfaces may hold paleoclimate records and elucidate important geologic processes involving volatiles, atmospheres, topography, and climate. Sputnik Planitia on Pluto and the well-studied north and south polar layered deposits (NPLD and SPLD) of Mars are examples. Ice peripheral to these main deposits may be even more sensitive to climatic changes. At northern martian latitudes, 18 outlying H2O ice mounds have previously been mapped within impact craters (Fig. 1a) near the NPLD. Here, we use remote sensing observations from New Horizons and Mars orbital spacecraft to study similar features in craters near Sputnik Planitia and the SPLD. We identify tens of outlying topographic mounds in craters near the SPLD (Fig. 1b) and five bright albedo features in craters near Sputnik Planitia (Fig. 1c). We assess the possibility that these deposits are analogous to the H2O ice mounds at northern martian polar latitudes. The southern martian deposits are physically diverse, but always include convex topography and host craters >15 km in diameter. We interpret at least some of them to be composed of H2O ice like their northern counterparts. The five features on Pluto are located in similarly sized craters and have corresponding spectral detections of N2 ice. One (Fig. 1c) has topography very similar to martian ice mounds, including a convex shape up to 160 m thick. We conclude it is an N2 ice mound, equivalent to Mars' H2O ice mounds in that crater topography provides a favorable microclimate for volatiles. The mound may preserve a paleoclimate record that would be erased in Sputnik Planitia by convection. Using a finite element model, we estimate flow velocities of this N2 ice mound to be 1 cm/yr, implying it may be younger than the other four which could have topography subdued by viscous relaxation. We compare the properties and possible formation mechanisms of these features to test the hypothesis that Pluto's ice cycle is similar to Mars' in certain periods of its orbital history. Figure 1. THEMIS images of ice mounds in the martian craters (a) Louth and (b) Deseado near the NPLD and SPLD, with extracted MOLA topographic profiles. (c) New Horizons base map of the five outlying volatile deposits in craters on Pluto, with extracted topographic profile from crater 3 and corresponding ice flow simulation.

Streamlined Island

NASA Image and Video Library

2014-04-15

This image from NASA 2001 Mars Odyssey spacecraft shows a streamlined island in a broad channel in Chryse Planitia. The channel is part of the outflow region of Lobo Vallis, a northern branch of Kasei Valles.

Investigating the volcanic versus aqueous origin of the surficial deposits in Eastern Elysium Planitia, Mars

NASA Astrophysics Data System (ADS)

Voigt, Joana R. C.; Hamilton, Christopher W.

2018-07-01

The Elysium Volcanic Province consists of numerous overlapping flow units and may include the youngest lava flows on Mars. However, it is possible that these volcanic units have been modified or overprinted by aqueous processes. Understanding the timing of the igneous and aqueous events in this region is therefore essential for constraining the geological and environmental history of Mars during the Amazonian Period. We investigate the geologic evolution of Eastern Elysium Planitia to determine the relationship between major units, with the support of a geological map and chronological constraints from crater size-frequency distributions. We also evaluate the hypothesized origin of these units via volcanic, fluvial, and/or fluvioglacial processes using a detailed facies-mapping approach. The study area includes the Eastern Cerberus Fossae, Rahway Valles, and Marte Vallis. The surficial deposits in Rahway Valles were formerly interpreted to be modified by fluvial and fluvioglacial processes. However, our facies map reveals that the surface of Eastern Elysium Planitia includes nineteen morphologically distinct regions (i.e., facies), which are interpreted to be the products of flood lava volcanism, including: ´a´ā, pāhoehoe, and transitional lava flow types. In contrast to previous studies, which determined that Rahway Valles and Marte Vallis consist of two distinct geologic units with Middle to Late Amazonian ages, the results of this work show that the region was resurfaced by at least two volcanic flows with much younger ages of 20.0 Ma and 8.8 Ma. Furthermore, by coupling results of our geologic and facies mapping with chronological constraints as well as subsurface information provided by Shallow Radar reflectors, we show that there is an erosional unconformity located between the two youngest lava flow units in Marte Vallis. We interpret that this unconformity was generated by a catastrophic aqueous flooding event that occurred only 8.8 - 20.0 Ma ago. This implies alternating episodes of volcanism and aqueous flooding that have continued into the geologically recent past on Mars, and may again occur within Elysium Planitia.

Large Bright Ripples

NASA Technical Reports Server (NTRS)

2004-01-01

3 February 2004 Wind is the chief agent of change on Mars today. Wind blows dust and it can move coarser sediment such as sand and silt. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows bright ripples or small dunes on the floors of troughs northeast of Isidis Planitia near 31.1oN, 244.6oW. The picture covers an area 3 km (1.9 mi) wide; sunlight illuminates the scene from the lower left.

CD-ROM publication of the Mars digital cartographic data base

NASA Technical Reports Server (NTRS)

Batson, R. M.; Eliason, E. M.; Soderblom, L. A.; Edwards, Kathleen; Wu, Sherman S. C.

1991-01-01

The recently completed Mars mosaicked digital image model (MDIM) and the soon-to-be-completed Mars digital terrain model (DTM) are being transcribed to optical disks to simplify distribution to planetary investigators. These models, completed in FY 1991, provide a cartographic base to which all existing Mars data can be registered. The digital image map of Mars is a cartographic extension of a set of compact disk read-only memory (CD-ROM) volumes containing individual Viking Orbiter images now being released. The data in these volumes are pristine in the sense that they were processed only to the extent required to view them as images. They contain the artifacts and the radiometric, geometric, and photometric characteristics of the raw data transmitted by the spacecraft. This new set of volumes, on the other hand, contains cartographic compilations made by processing the raw images to reduce radiometric and geometric distortions and to form geodetically controlled MDIM's. It also contains digitized versions of an airbrushed map of Mars as well as a listing of all feature names approved by the International Astronomical Union. In addition, special geodetic and photogrammetric processing has been performed to derive rasters of topographic data, or DTM's. The latter have a format similar to that of MDIM, except that elevation values are used in the array instead of image brightness values. The set consists of seven volumes: (1) Vastitas Borealis Region of Mars; (2) Xanthe Terra of Mars; (3) Amazonis Planitia Region of Mars; (4) Elysium Planitia Region of Mars; (5) Arabia Terra of Mars; (6) Planum Australe Region of Mars; and (7) a digital topographic map of Mars.

Utopia and Hellas basins, Mars: Twins separated at birth

NASA Astrophysics Data System (ADS)

Searls, Mindi L.; Banerdt, W. Bruce; Phillips, Roger J.

2006-08-01

Using topography and gravity data as constraints, we formulate spherical harmonic thin elastic-shell models to determine the subsurface structure of the Hellas and Utopia basins. For Hellas, we show that our model is consistent with the elastic thickness results of McGovern et al. (2002, 2004). The thin elastic lithosphere at the time of formation implies that Hellas is close to isostatic. Since Utopia formed earlier, we argue that an isostatic assumption is justified for the Utopia basin before it was filled. From this supposition, we derive a system of equations that allows us to solve for the amount of fill, the prefill topography, and the amount of flexure due to the fill within the Utopia basin. An analysis of the parameter space shows that the fill density and the amount of fill is strongly dependent on the elastic thickness at the time of infilling. A thinner elastic lithosphere favors a denser fill, while a thicker lithosphere will allow for less dense material. Likewise, larger crustal thickness values lead to smaller fill density values. The presence of quasi-circular depressions, interpreted as impact craters, within the Utopia basin indicates that the majority of the material within Utopia was deposited prior to 4.04-4.11 Ga. The early timing for the deposition combined with the heat imparted by the basin forming event argues for a thinner lithosphere which could, in turn, suggest fill densities that are more consistent with a volcanic load than with pure sediment or ice-rich material. These results are supported using an alternative method of determining the amount of fill and flexure within Utopia. This model assumes that Hellas and Utopia were initially identical and that the only difference in their subsequent evolution was the addition of material in the Utopia basin. The volume of material needed to fill Utopia is immense (on the order of 50 million km3 or more). The high density obtained for the fill requires that it contain a large igneous component, the source of which is problematic. Relaxing the isostatic assumption to a reasonable degree perturbs the density bound only slightly.

Flooded Crater

NASA Image and Video Library

2003-04-04

This image from NASA Mars Odyssey spacecraft shows a flooded crater in Amazonis Planitia. This crater has been either flooded with mud and or lava. The fluid then ponded up, dried and formed the surface textures we see today.

Textures in Arcadia Planitia

NASA Image and Video Library

2003-03-07

An unusual mix of textures is featured in this image from NASA Mars Odyssey spacecraft of a surface east of the Phlegra Montes. Scabby mounds, commonly occurring around degraded craters, mix with a more muted, knobby terrain.

The initial exploration of Mars - Rationale for a return mission to Chryse Planitia and the Viking 1 Lander

NASA Technical Reports Server (NTRS)

Craddock, Robert A.

1992-01-01

A discussion of the concepts behind planning a landing site on Mars is presented. On the basis of the engineering constraints and the scientific objectives which are likely to be imposed on the first few missions to the surface, reasons for supporting a return to Chryse Planitia and the Viking 1 landing site are given. Samples from the Hesperian ridged plains would be useful in establishing an absolute age for the present crater chronology, and samples of soils from the vicinity of the Viking 1 lander would be useful in determining the significance of the results from the Viking biological experiments. Soil samples would provide consistency between unmanned and manned missions, may contain fossil microorganisms, and could be useful in determining the mechanism responsible for outflow channel formation.

Mars Pathfinder and the exploration of southern Amazonis Planitia

NASA Technical Reports Server (NTRS)

Barlow, Nadine G.

1994-01-01

The southern region of Amazonis Planitia provides a variety of target terrains for a roving vehicle such as the Mars Pathfinder Mission. A landing site is proposed at 4 deg N latitude 162 deg W longitude. This area has a reference altitude of between 0 and -1 km and consists of relatively smooth Amazonian-aged deposits within the entire 100 x 200 km landing ellipse. The proposed landing site is within the Upper Member Medusae Fossae Formation deposits (Amu) and near the boundary with Middle Member Medusae Fossae Formation deposits (Amm) and Member 1 Arcadia Formation plains (Aa(sub 1)). Slightly further afield are 107-km-diameter Nicholson crater, its ejecta deposits, and knobby terrain of proposed Hesperian age (HNu). Depending on the exact landing site of the spacecraft and the traverse distance of the rover, these materials also may be sampled.

Investigation of the relationship of crater depths and diameters in selected regions of Mars

NASA Astrophysics Data System (ADS)

Hsu, Hsin-Jen

2013-03-01

Impact craters are common geomorphological features on Mars. The density of craters is different among various regions. Higher crater density means older terrain. Craters can be divided into two types by the interior morphology: simple and complex. The cavity of Simple craters is bowl-shape, and complex craters display various interior features, such as central peaks. The depth/diameter ratio (d/D) of simple craters is larger than that of complex craters. The transition diameter from simple to complex morphologies ranges between 5 and 10 km, and is commonly cited to be about 7 km in the equatorial regions and 6 km near the poles, but the exact value also could vary with terrain type. In this research, seven regions, Amazonis Planitia, Arabia Terra, Chryse Planitia, Hesperia Planum, Isidis Planitia, Solis/Syria/Sinai Planum, and Terra Sirenum, were selected to investigate the onset diameter of complex craters and the relationship of crater diameter and depth in these regions on Mars in order to understand how the geology affects crater d/D. The analysis revealed that the slopes of the d/D relations are different, and these are linked to the surface material in different regions. The onset diameters in young volcanic regions with stronger material are slightly higher than older volcanic regions, and much higher than that of volatile regions. The research proves the different geological units can affect the morphology and morphometry of craters.

Near-surface ice-rich regolith in mid Utopia Planitia, Mars, and its formation by thaw-freeze cycling

NASA Astrophysics Data System (ADS)

Soare, R. J.; Conway, S. J.

2012-12-01

We have used all relevant HiRISE, MOC, THEMIS and CTX images of mid Utopia Planitia (UP; ~30-600N; ~65-1010E) to identify and then map the spatial association of flat-floored and scalloped depressions, small-sized (~150m) polygonal patterned-ground and polygon-junction/trough pits. In periglacial regions on Earth such as northern Yakutia and Alaska, similar landscape-assemblages comprised of thermokarst lakes or alases, ice-wedge polygons and polygon-junction ponds are markers of ice-rich permafrost (dominated by lens-like segregation ice). The distribution of these Martian putative periglacial-landforms (PPLs) cross cuts geological units that have a wide range of ages and types, i.e. HBU1 (early Hesperian, lava) - AEta (late Hesperian, fluvial) - ABa (late Amazonian, aeolian), and suggests that a previously unidentified periglacial unit (PUPU) exists in the region. Regardless of whether the PPLs form by means of sublimation or thaw, questions concerning the origin of the hypothesised ice-rich permafrost itself have been largely overlooked in the literature. Based on our most recent observations and findings, we propose five things. First, the PUPU is tens of metres deep, regional in spatial extent, shows sub-horizontal banding, and is an ice-enriched loess-like (or fine-grained) unit comprised principally of segregated ice. Second, the PUPU is distinct from and underlies a regional high-albedo mantle that does not show periglacial landscape modification or features. Heretofore, numerous workers have hypothesised that the scalloped depressions, small-sized polygons and polygon-junction/trough pits that are ubiquitous in the region are the product of mantle degradation by sublimation. Third, the fact that the PUPU is overlain by a mantle not modified by periglacial processes leads one to believe that the formation of a periglacial landscape in mid UP is not as recent as some workers have thought. Fourth, the loess-like material could comprise weathered and eroded material derived from the north polar cap deposits and transported to the mid-latitudes by katabatic winds. Fifth, the ice-enrichment of the PUPU is distinct from and independent of loess deposition and accumulation. As is the case with their presumed analogues on Earth, we hypothesise that the Martian PPLs form in fine-grained sediments that have accumulated episodically; these sediments undergo post-deposition infiltration by melt water, possibly derived of surface snow or ice precipitated atmospherically. Fine-grained sediments facilitate cryosuction, which is the attraction of water towards a freezing front, and the formation of segregated ice lenses. Metre-thick (near-surface) ice-cemented permafrost has been observed in the Antarctic Dry Valleys. Diffusive exchange between the atmosphere and the near-surface sediments is the process by which ice cementation could have taken place. However, diffusive exchanges to the full depth of the PUPU are not considered to be possible unless this occurs episodically.

Diurnal Temperature Regime in the Regolith Surface Layer of the Lagado Planitia Region on Phobos: Model Predictions for Different Seasons

NASA Astrophysics Data System (ADS)

Kuzmin, R. O.; Zabalueva, E. V.

2018-03-01

The paper contains the data on the thermal and physical characteristic of the surface regolith of the Martian satellite Phobos obtained from the spaceborne remote sensing (with the Mariner 9, Viking, and Mars Global Surveyor orbiters and the Phobos-2 spacecraft) and the results of the numerical modeling of the thermal regime in the surface regolith (on diurnal and seasonal scales) performed for the prospective landing site in the Lagado Planitia region located in the anti-Martian hemisphere of Phobos.

Nature and distribution of surficial deposits in Chryse Planitia and vicinity, Mars

NASA Technical Reports Server (NTRS)

Arvidson, Raymond E.; Guinness, Edward A.; Dale-Bannister, Mary A.; Adams, John; Smith, Milton

1989-01-01

The properties and lateral distribution of surficial units for the Mutch Memorial Station region are examined, using color images of the dust deposits in the region obtained at variable incidence angles during sol 611. The radiance factors from the region are compared with values derived from Viking Orbiter images and the materials in and around the region are described. Viking, earth-based, and laboratory spectra are compared and a model is constructed for the nature and distribution of surficial units in the Chryse Planitia region.

Mars - Hellas Planitia gravity analysis

NASA Technical Reports Server (NTRS)

Sjogren, W. L.; Wimberley, R. N.

1981-01-01

Doppler radio tracking data from Viking Orbiter 1 has provided new detailed observations of gravity variations over Hellas Planitia. Line-of-sight Bouguer gravity definitely indicates that isostatic adjustment has occurred. Two theoretical models were tested to obtain fits to the gravity data. Results for a surface deficit model, and a model with a surface deficit and a mass excess at depth are displayed. The mass-at-depth model produced very marked improvement in the data fit as compared to the surface deficit model. The optimum depth for the mass excess is 130 km.

Peneus Patera

NASA Image and Video Library

2011-07-08

The unusual shallow, scalloped depressions in this image from NASA 2001 Mars Odyssey spacecraft are located on the margin Peneus Patera, south of Hellas Planitia. It may be that volatiles, such as ice, are involved in the formation of these depressions.

Regional Mapping and Spectral Analysis of Mounds in Acidalia Planitia, Mars

NASA Technical Reports Server (NTRS)

Amador, E. S.; Allen, Carlton; Oehler, D. Z.

2010-01-01

Acidalia Planitia is a approx.3000 km diameter planum located in the northern plains of Mars. It is believed to be a sedimentary basin containing an accumulation of sediments brought by Hesperian outflow channels that drained the Highlands. A large number of high-albedo mounds have been identified across this basin [1-2] and understanding the process that formed them should help us understand the history of this region. Farrand et al. [2] showed that the mounds are dark in THEMIS (Thermal Emission Imaging System) nighttime IR (infrared) image data. This implies that the mounds have a lower thermal inertia than the surrounding plains (Fig. 1), suggesting that the material of the mounds is fine-grained or unconsolidated. Farrand et al. [2] also reviewed potential analogs for the mounds and concluded that a combination of mud volcanoes with evaporites around geysers or springs is most consistent with all the data. We have built on this work by creating regional maps of the features and analyzing CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) data to see if there are mineralogical differences between the mounds and surrounding plains.

Mawrth Vallis - False Color

NASA Image and Video Library

2015-09-30

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows where Mawrth Vallis empties into Chryse Planitia.

Crater - False Color

NASA Image and Video Library

2015-01-14

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image from NASA 2001 Mars Odyssey spacecraft shows an unnamed crater in Acidalia Planitia.

Small Mounds in Chryse Planitia

NASA Image and Video Library

2011-07-15

The suggested area in this observation from NASA Mars Reconnaissance Orbiter is characterized by a group of cones, shield-like features, and round mounds. They are a few hundred meters to kilometers in diameter but their heights are unknown.

Geometric Comparisons of Selected Small Topographically Fresh Volcanoes in the Borealis and Elysium Planitia Volcanic Fields, Mars: Implications for Eruptive Styles

NASA Technical Reports Server (NTRS)

Taylor, K.; Sakimoto, S. E. H.; Mitchell, D.

2002-01-01

MOLA (Mars Orbiter Laser Altimeter) data from small, topographically fresh volcanoes from the Elysium and Borealis regions were gridded and analyzed using GMT (Generic Mapping Tools) programs. Results compare eruptive styles of the two regions, and draw conclusions about the different volcanic regions. Additional information is contained in the original extended abstract.

Northeast Isidis

NASA Technical Reports Server (NTRS)

2005-01-01

7 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a mesa in northeastern Isidis Planitia. The mesa might be a remnant of terrain that once more extensively covered the region.

Location near: 20.3oN, 267.7oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

Volcanism in Elysium Planitia, Mars

NASA Technical Reports Server (NTRS)

Mouginis-Mark, P. J.

1984-01-01

Geomorphic mapping revealed that the three volcanic constructs within Elysium Planitia (Hecates Tholus, elysium Mons and Albor Tholus) are very different in their overall morphology and represent three distinct types of martian volcano. Hecates Tholus was found to possess the most likely possible example of a young, explosively generated, air fall deposit, while the volume of magma erupted from Elysium Mons appears to have been orders of magnitude larger than that erupted from Albor Tholus. A primary aim of the regional geological analysis of Elysium Planitia is to further understand the volcanic and tectonic evolution of the area by the identification and interpretation of individual lava flows and their source vents. Lava flow size, spatial distribution, flow direction and the stratigraphic relationships of these lava flows to adjacent structural features were all measured. The topographic form of Elysium Mons has totally controlled the flow direction of lava flows within Elysium Planitia. Lava flows from Elysium Mons can be traced for distances of 150 to 250 km in a radial direction from the volcano. Parasitic vents located beyond the recognizable volcanic construct also conform to this radial pattern. A second unusual characteristic of the Elysium Planitia region is the high frequency of occurrence of sinuous channels that are morphologically similar to lunar sinuous rilles.

Wrinkle ridges of Arcadia Planitia, Mars

NASA Technical Reports Server (NTRS)

Plescia, J. B.

1993-01-01

Wrinkle ridges of Arcadia Planitia were examined to determine their morphology, spatial distribution, and the amount of crustal shortening and strain they accommodate. Ridges trend generally northward, but their orientation and distribution are strongly controlled by the relief of the underlying hobby material. Ridges begin or end at inselbergs of older terrain and are associated with buried craters. Arcadia Planitia ridges have an average width of 3425 m and accommodate an average folding shortening of 3 m and a faulting shortening of 55 m; mean total shortening is 57 m. Three east-west transects were constructed at 20 deg 25 deg and 28 deg N to estimate regional shortening and strain. Average total shortening across the transects is about 900 m, corresponding to a regional compressive strain of 0.06 percent. The total shortening and compression across Arcadia Planitia are less than in Lungae Planum. Faults associated with the Arcadia ridges are inferred to have a westward dip compared with an eastward dip for Lungae Planum ridges. The general levels of compression and symmetric orientation of the ridges suggest a regionally organized stress system.

An Inversion of Gravity and Topography for Mantle and Crustal Structure on Mars

NASA Technical Reports Server (NTRS)

Kiefer, Walter S.; Bills, Bruce G.; Nerem, R. Steven

1996-01-01

Analysis of the gravity and topography of Mars presently provides our primary quantitative constraints on the internal structure of Mars. We present an inversion of the long-wavelength (harmonic degree less than or equal to 10) gravity and topography of Mars for lateral variations of mantle temperature and crustal thickness. Our formulation incorporates both viscous mantle flow (which most prior studies have neglected) and isostatically compensated density anomalies in the crust and lithosphere. Our nominal model has a 150-km-thick high-viscosity surface layer over an isoviscous mantle, with a core radius of 1840 km. It predicts lateral temperature variations of up to a few hundred degrees Kelvin relative to the mean mantle temperature, with high temperature under Tharsis and to a lesser extent under Elysium and cool temperatures elsewhere. Surprisingly, the model predicts crustal thinning beneath Tharsis. If correct, this implies that thinning of the crust by mantle shear stresses dominates over thickening of the crust by volcanism. The major impact basins (Hellas, Argyre, Isidis, Chryse, and Utopia) are regions of crustal thinning, as expected. Utopia is also predicted to be a region of hot mantle, which is hard to reconcile with the surface geology. An alternative model for Utopia treats it as a mascon basin. The Utopia gravity anomaly is consistent with the presence of a 1.2 to 1.6 km thick layer of uncompensated basalt, in good agreement with geologic arguments about the amount of volcanic fill in this area. The mantle thermal structure is the dominant contributor to the observed geoid in our inversion. The mantle also dominates the topography at the longest wavelengths, but shorter wavelengths (harmonic degrees greater than or equal to 4) are dominated by the crustal structure. Because of the uncertainty about the appropriate numerical values for some of the model's input parameters, we have examined the sensitivity of the model results to the planetary structural model (core radius and core and mantle densities), the mantle's viscosity stratification, and the mean crustal thickness. The model results are insensitive to the specific thickness or viscosity contrast of the high-viscosity surface layer and to the mean crustal thickness in the range 25 to 100 km. Models with a large core radius or with an upper mantle low-viscosity zone require implausibly large lateral variations in mantle temperature.

Lunar and Planetary Science XXXV: Special Session: Mars Climate Change

NASA Technical Reports Server (NTRS)

2004-01-01

The titles in this section include: 1) Mars South Pole CO2 Paleoatmosphere; 2) Do SNC Noble Gas and Deuterium Data Provide Evidence for Large Cometary Impact Between 1300-300 Ma on Mars? 3) Medusae Fossae Formation: Ice-rich Airborne Dust Deposited During Periods of High Obliquity? 4) Ascraeus Mons, Mars: Characterisation and Interpretation of the Fan-shaped Deposit on Its Western Flank; 5) Evidence of Recent Glaciation in Elysium Planitia, Mars; 6) Craters and Other Circular Features in the Northern Circumpolar Area, Mars; 7) Intra-Annual Variations of the Martian Swiss-Cheese Terrain; 8) Drastic Climate Change of Mars Induced by H2O Ice Caps; 9) Modelling the Mass Balance of the North Polar Ice Cap on Mars.

Calahorra Crater - False Color

NASA Image and Video Library

2014-12-24

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image from NASA 2001 Mars Odyssey spacecraft shows part of Calahorra Crater in Chryse Planitia.

Identification of a Spectrally and Thermophysically Unique Region in Northern Amazonis Planitia, Mars: Surface Analysis using TES and THEMIS Data

NASA Astrophysics Data System (ADS)

Rogers, D.; Christensen, P. R.

2002-12-01

An intermediate-albedo (0.23-0.24) region located in northeastern Amazonis Planitia (approximately 900 km2 in area, centered at 40§N, 150§W) has been discovered to have a unique combination of certain spectral and thermophysical properties. The range of thermal inertia values for this region is 40-150 J/m2Ks1/2. On Mars, these values are usually indicative of a thick deposit of very fine-grained material (<63 microns) [1]. However, unlike typical dust deposits on Mars, this region exhibits moderate spectral contrast, with surface emissivity values ranging from 0.94-0.97 near 1030 cm-1. These emissivity values are uncharacteristic of fine-grained material [e.g., 2]. The modal mineralogy obtained by linear deconvolution of selected emissivity spectra from at least four different orbits over this region is not different than that reported for the Acidalia Planitia andesitic surface [3], within the mineral abundance detection limit estimated for TES [4]. However, the atmospherically-corrected surface spectral shape is distinct from the surface spectra common to Acidalia Planitia [3], Syrtis Major [3, 4], Sinus Meridiani [5] and Nili Fossae [6]. A spectral index was developed that describes the shape of a concave-down portion of the surface spectrum near 900 cm-1. A global 4 pixel-per-degree map of this index shows that the spectral character is unique to this region on Mars. MOC and THEMIS visible images available for this area show a uniform geomorphology consisting of parallel sinuous features trending NW-SE. Finally, THEMIS IR images show a sharp temperature contact that corresponds with the boundary of this area in the spectral index map. There are likely to be other explanations for reconciling the low thermal inertia with high spectral feature depth, however a favored hypothesis for this anomalous surface is that it is composed of a consolidated but highly porous material. This and other interpretations for this region will be discussed. References: [1] Kieffer et al. 1977, JGR, 82, 4249-4291; [2] Moersch and Christensen, 1995, JGR, 100, 7465-7477; [3] Bandfield et al. 2000, Science, 287, 1626-1630; [4] Christensen et al. 2000, JGR, 105, 9609-9621; [5] Christensen et al. 2000, JGR, 105, 9623-9642; [6] Hamilton et al. 2001, LPSC XXXII Abstracts, abstract 2184

Mud Volcanoes - A New Class of Sites for Geological and Astrobiological Exploration of Mars

NASA Technical Reports Server (NTRS)

Allen, C.C.; Oehler, D.Z.; Baker, D.M.

2009-01-01

Mud volcanoes provide a unique low-temperature window into the Earth s subsurface - including the deep biosphere - and may prove to be significant sources of atmospheric methane. The identification of analogous features on Mars would provide an important new class of sites for geological and astrobiological exploration. We report new work suggesting that features in Acidalia Planitia are most consistent with their being mud volcanoes.

Equatorial locations of water on Mars: Improved resolution maps based on Mars Odyssey Neutron Spectrometer data

NASA Astrophysics Data System (ADS)

Wilson, Jack T.; Eke, Vincent R.; Massey, Richard J.; Elphic, Richard C.; Feldman, William C.; Maurice, Sylvestre; Teodoro, Luís F. A.

2018-01-01

We present a map of the near subsurface hydrogen distribution on Mars, based on epithermal neutron data from the Mars Odyssey Neutron Spectrometer. The map's spatial resolution is approximately improved two-fold via a new form of the pixon image reconstruction technique. We discover hydrogen-rich mineralogy far from the poles, including ∼10 wt.% water equivalent hydrogen (WEH) on the flanks of the Tharsis Montes and >40 wt.% WEH at the Medusae Fossae Formation (MFF). The high WEH abundance at the MFF implies the presence of bulk water ice. This supports the hypothesis of recent periods of high orbital obliquity during which water ice was stable on the surface. We find the young undivided channel system material in southern Elysium Planitia to be distinct from its surroundings and exceptionally dry; there is no evidence of hydration at the location in Elysium Planitia suggested to contain a buried water ice sea. Finally, we find that the sites of recurring slope lineae (RSL) do not correlate with subsurface hydration. This implies that RSL are not fed by large, near-subsurface aquifers, but are instead the result of either small ( < 120 km diameter) aquifers, deliquescence of perchlorate and chlorate salts or dry, granular flows.

Radar Soundings of the Subsurface of Mars

NASA Technical Reports Server (NTRS)

Picardi, Giovanni; Plaut, Jeffrey J.; Biccari, Daniela; Bombaci, Ornella; Calabrese, Diego; Cartacci, Marco; Cicchetti, Andrea; Clifford, Stephen M.; Edenhofer, Peter; Farrell, William M.;

MC-13 Syrtis Major Region

NASA Technical Reports Server (NTRS)

1994-01-01

Mars digital-image mosaic merged with color of the MC-13 quadrangle, Syrtis Major region of Mars. The central part is dominated by dark dust and lava flows of the Syrtis Major Planitia region. These lava flows are partly bounded to the east by a large depression, Isidis basin, which contains smooth plains, and to the west and north by heavily cratered and moderately faulted highlands. Latitude range 0 to 30 degrees, longitude range -90 to -45 degrees.

Tectonic History of the Terrestrial Planets

NASA Technical Reports Server (NTRS)

Solomon, Sean C.

1993-01-01

The topics covered include the following: patterns of deformation and volcanic flows associated with lithospheric loading by large volcanoes on Venus; aspects of modeling the tectonics of large volcanoes on the terrestrial planets; state of stress, faulting, and eruption characteristics of large volcanoes on Mars; origin and thermal evolution of Mars; geoid-to-topography ratios on Venus; a tectonic resurfacing model for Venus; the resurfacing controversy for Venus; and the deformation belts of Lavinia Planitia.

Ares 3 and The Martian

NASA Image and Video Library

2015-03-11

This image from NASA Mars Reconnaissance Orbiter shows a region of Acidalia Planitia which is covered by dense fields of boulders up to several meters high. In "The Martian" by Andy Weir (watch for the movie in late 2015), stranded astronaut Mark Watney spends most of his time at the "Ares 3" site in southern Acidalia Planitia. The book describes Acidalia as flat and easy to drive over; he even drives to the Pathfinder landing site and back. This region of Mars is actually far more diverse, interesting, and hazardous to drive over than depicted in the novel. These two images (this observation and ESP_019783_2115) are close to the Ares 3 landing site as shown in a map at the front of the novel, and shows many mounds, perhaps ancient volcanoes resulting from lava-water interaction or eruption of muddy sediments. Much of Acidalia Planitia is covered by dense fields of boulders up to several meters high that would be difficult to drive around. There are also fissures associated with giant polygons, with steep rocky slopes that would be impassable. There are elongated fields of dense secondary craters where the surface is extremely rough at scales near the size of the rover. When our hero travels into Arabia Terra it is described as much rockier than Acidalia, but the the opposite is generally true: much of Arabia is dust mantled and smooth at the scale of a rover. People commonly assume that smooth at large scales (kilometers) means smooth at small scales ( meters to tens of meters). Often on Mars, the exact opposite is seen: large flat low areas are more wind-scoured, removing fine materials and leaving rocks and eroded bedrock. http://photojournal.jpl.nasa.gov/catalog/PIA19306

To Great Depths

NASA Image and Video Library

2017-03-22

Hellas is an ancient impact structure and is the deepest and broadest enclosed basin on Mars. It measures about 2,300 kilometers across and the floor of the basin, Hellas Planitia, contains the lowest elevations on Mars. The Hellas region can often be difficult to view from orbit due to seasonal frost, water-ice clouds and dust storms, yet this region is intriguing because of its diverse, and oftentimes bizarre, landforms. This image from eastern Hellas Planitia shows some of the unusual features on the basin floor. These relatively flat-lying "cells" appear to have concentric layers or bands, similar to a honeycomb. This "honeycomb" terrain exists elsewhere in Hellas, but the geologic process responsible for creating these features remains unresolved. The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. [The original image scale is 52.2 centimeters (20.6 inches) per pixel (with 2 x 2 binning); objects on the order of 157 centimeters (61.8 inches) across are resolved.] North is up. http://photojournal.jpl.nasa.gov/catalog/PIA21570

Grid-mapping Hellas Planitia, Mars - Insights into distribution, evolution and geomorphology of (Peri)-glacial, fluvial and lacustrine landforms in Mars' deepest basin

NASA Astrophysics Data System (ADS)

Voelker, M.; Hauber, E.; Schulzeck, F.; Jaumann, R.

2017-10-01

Traditional maps of Hellas Planitia, the most prominent impact basin on Mars, have focused on the delineation of continuous surface units. We applied the newly developed grid-mapping method in order to quantitatively analyze the distribution and geostatistics of selected (peri)-glacial, fluvial, and lacustrine landforms. The study area was subdivided in grid cells with a mesh size of 20 × 20 km, and more than 10,000 grids have been inspected manually in a GIS environment at a mapping scale of 1:30,000. Each grid has been checked for the presence or absence of a landform. Thus, we were able to statistically evaluate the geographical behavior of landforms with respect to elevation, slope inclination, aspect, and other parameters. We searched for 24 pre-selected landforms. However, only 15 of them had a sufficient abundance for scientific research. Whereas the latitude-dependent mantle is widespread in most of Hellas, it was found to be mostly missing in the northeastern part, likely a result of desiccating winds circulating clockwise within the basin. The location and morphologic expression of scalloped terrain also seems to be influenced by winds, as the local orientation of scalloped depressions appears to be aligned along the dominant wind direction, indicating that insolation is not the only factor controlling their formation. Hellas Planitia has been suggested as the site of a former sea. We also searched each grid for the presence of possible shorelines. Despite the small scale of our mapping, no clear evidence for coastal landforms has been detected. Our results reveal a distinctive asymmetry with respect to fluvial channels and Noachian light-toned sediments along the rim of the impact basin. While the northern rim shows a high density of both channels and sediments, the southern counterpart basically lacks channels and light-toned deposits. We suggest different climatic conditions for this imbalance, as the northern part of Hellas likely experienced higher temperatures throughout most of Mars' evolution, while the colder conditions at the southern rim may have prohibited aqueous processes, preventing the development of channels and related sediments. As Hellas contains the deepest areas of the planet's surface, and thus the highest air pressure, its climatic environment can exceed the triple point of water until today, making it a potential habitat. However, our results have shown that the basin floor displays only a very low density of landforms that may indicate liquid water and ice, and especially gullies and viscous-flow features are scarce. The high air pressure and relatively mild temperatures in Hellas decrease the relative atmospheric water content, resulting in a desiccated air and soil, and hence, may explain the lack of viscous-flow features and gullies. All these findings extended our knowledge not only of Hellas Planitia, but of the screened landforms themselves too. In conclusion, small-scale grid-mapping made it possible to recognize large-scale patterns and distributions in Hellas Planitia.

Abstracts of the Annual Meeting of Planetary Geologic Mappers, Tucson, AZ 2007

USGS Publications Warehouse

Gregg, Tracy K.P.; Tanaka, Kenneth L.; Saunders, R. Stephen; Bleamaster, Leslie F.

2007-01-01

Introduction Report of the Annual Mappers Meeting Planetary Science Institute Tucson, Arizona June 28 and 29, 2007 Approximately 22 people attended this year's mappers meeting, and many more submitted abstracts and maps in absentia. The 2007 meeting was convened by Tracy Gregg, Les Bleamaster, Steve Saunders, and Ken Tanaka and was hosted by David Crown and Les Bleamaster of the Planetary Science Institute (PSI) in Tucson, Arizona. Oral presentations and poster discussions took place on Thursday, June 28 and Friday, June 29. This year's meeting also included a unique opportunity to visit the operations centers of two active Mars missions; field trips to the University of Arizona took place on Thursday and Friday afternoons. Outgoing Geologic Mapping Subcommittee (GEMS) chairperson, Tracy Gregg, commenced the meeting with an introduction and David Crown followed with a discussion of logistics and the PSI facility; Steve Saunders (Planetary Geology and Geophysics Discipline Scientist) then provided a brief program update. Science presentations kicked off with Venus mapper Vicki Hansen and graduate students Eric Tharalson and Bhairavi Shankar of the University of Minnesota, Duluth, showing a 3-D animation of the global distribution of tesserae and discussing the implications, a progress report for V-45 quadrangle mapping, and a brief discussion of circular lows. Les Bleamaster (PSI) followed with a progress report on mapping of the V-50 quadrangle and the 1:10M Helen Planitia quadrangle. David Crown (PSI) concluded the Venus presentations with a discussion of progress made on the V-30 quadrangle. The remainder of Thursday's presentations jumped around the Solar System including Mars, Io, and Earth. Ken Tanaka of the U.S. Geological Survey (USGS) began the afternoon with a general discussion of the status of the planetary mapping program at USGS. Buck Janes (University of Arizona) provided background information about the Mars Odyssey Gamma Ray Spectrometer (GRS) and presented some new element maps, which may be useful for geologic mapping. Dave Williams of Arizona State University reported on the progress of his global Io map and James Dohm (University of Arizona) discussed results of terrestrial remote mapping studies. Thursday afternoon, the mappers were given a tour of the High Resolution Imaging Science Experiment (HiRISE) operations facility and were given some basic information about how the images are obtained, processed, and publicly released. With official GEMS transition completed at lunch on Thursday, incoming GEMS chair Leslie Bleamaster took the reigns of Friday's meeting. Science presentations began with Ken Tanaka discussing 1:20M-scale global and 1:2M-scale polar mapping of Mars. Jim Zimbelman (Smithsonian Institution) described his 1:1M Medusae Fossae map (MC-8 SE), which is nearing completion, and new mapping (MC-16 NW and MC-23 NW) to further evaluate the Medusae Fossae. Brent Garry, also of the Smithsonian Institution, presented work on Ascraeus Mons. Peter Mouginis-Mark (University of Hawai`i) reported progress on his 1:200K and larger maps of Tooting crater and of the Olympus Mons summit caldera. Laszlo Keszthelyi (USGS) presented mapping of Athabasca Valles, with much of the credit going to Windy Jaeger. Jim Skinner (USGS) introduced a new mapping project including nine MTM quadrangles in the Utopia Planitia region. Tracy Gregg finished off the day's science presentations with discussion of Hesperia Planum. After discussion was complete, the group once again traveled to the University of Arizona - this time for a tour of the Mars Phoenix operations center. Principal Investigator Peter Smith beamed as he led mappers through the multi-million dollar facility. A main topic of discussion throughout the entire meeting was that of nomenclature, specifically how to classify the individual depressions at the tops of volcanoes. Paterae, as has been used for Mars, Venus, and Io, was suggested, but i

Gullied Depression

NASA Technical Reports Server (NTRS)

2006-01-01

26 February 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies formed in the wall of a depression located on the floor of Rabe Crater west of the giant impact basin, Hellas Planitia. Gullies such as these are common features on Mars, but the process by which they are formed is not fully understood. The debate centers on the role and source of fluids in the genesis of these features.

Location near: 44.1oS, 325.9oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

Erosional and depositional history of central Chryse Planitia

NASA Technical Reports Server (NTRS)

Crumpler, L. S.

1992-01-01

This map uses high resolution image data to assess the detailed depositional and erosional history of part of Chryse Planitia. This area is significant to the study of the global geology of Mars because it represents one of only two areas on the martian surface where planetary geologic mapping is assisted with 'ground truth.' In this case the ground truth was provided by Viking Lander 1. Additional questions addressed in this study are concerned with the following: the geologic context of the regional plains surface and the local surface of the Viking Lander 1 site; and the relative influence of volcanic, sedimentary, impact, aeolian, and tectonic processes at the regional and local scales.

The environs of viking 2 lander.

PubMed

Shorthill, R W; Moore, H J; Hutton, R E; Scott, R F; Spitzer, C R

1976-12-11

Forty-six days after Viking 1 landed, Viking 2 landed in Utopia Planitia, about 6500 kilometers away from the landing site of Viking 1. Images show that in the immediate vicinity of the Viking 2 landing site the surface is covered with rocks, some of which are partially buried, and fine-grained materials. The surface sampler, the lander cameras, engineering sensors, and some data from the other lander experiments were used to investigate the properties of the surface. Lander 2 has a more homogeneous surface, more coarse-grained material, an extensive crust, small rocks or clods which seem to be difficult to collect, and more extensive erosion by the retro-engine exhaust gases than lander 1. A report on the physical properties of the martian surface based on data obtained through sol 58 on Viking 2 and a brief description of activities on Viking 1 after sol 36 are given.

Security Blanket

NASA Technical Reports Server (NTRS)

2006-01-01

2 June 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows material on the floor of a crater in Noachis Terra, west of Hellas Planitia. Windblown features, both the large, dark-toned sand dunes and smaller, light-toned ripples, obscure and perhaps, protect portions of the crater floor from further modification by erosional processes.

Location near: 45.4oS, 331.2oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

Icelandic Analogs for Volcanic and Fluvial Processes on Mars

NASA Astrophysics Data System (ADS)

McEwen, A.; Burr, D.; Hardardottir, J.; Hoskuldsson, A.; Keszthelyi, L.; Lanagan, P.; Snorrason, A.; Thordarson, T.

2001-12-01

Iceland has proven to be an excellent location to study a wide range of Martian geologic analogs. Among these are basaltic volcanism and aqueous flooding--key geologic processes that have shaped the Martian surface and that remain active in Iceland. On both Mars and Iceland, volcanic units are interfingered in space and time with fluvial units. Well-preserved flood lavas in SE Elysium Planitia, Amazonis Planitia, and portions of the Tharsis rise are dominated by a distinctive morphology of plates and ridges, very similar to the "apalhraun" or "rubbly pahoehoe" of Iceland (Keszthelyi and Thordarson, 2000, GSA Abstract 52593). On both Iceland and Mars there are marginal regions of undisrupted inflated pahoehoe, small rootless cones, and long parallel structures in the wake of topographic obstacles. The Icelandic paleoflood channels of Jokulsa a Fjollum, extending from the Vatnajokull ice cap to the north coast, have eroded basaltic plains and provide many insights into morphologies seen on Mars. The manner in which different types of lava erode in a catastrophic flood is well illustrated and sometimes surprising. For example, there are channel floors where the crusts of inflated lavas have been completely stripped off by the floodwater, but then suddenly transitions upstream into a stretch with almost no erosion--even the cm-scale pahoehoe ropes are intact. This implies that significant aqueous floods could have occurred over some well-preserved lava flows on Mars. A streamlined "island" or mesa extending downstream from the volcanic crater Hrossaborg in Iceland appears to be mixture of remobilized older glacial deposits and a debris flow deposit. The debris flow apparently formed by collapse of the western outer crater slopes into the active floodwaters, diverting the flow northward; this process may have occurred on Mars at some of the impact craters eroded by outflow channels.

Hardened Dunes in Arcadia Planitia

NASA Image and Video Library

2014-10-29

NASA Mars Reconnaissance Orbiter HiRISE, with its high resolution and eight years in orbit about Mars, has shown that many dunes and ripples on the planet are active. This demonstrates that in some areas sand is loose enough and winds strong enough, that significant change can occur. Nevertheless, other Martian dunes are clearly *inactive*. This image in Arcadia Planitia shows dunes in a crater. Unlike active dunes on the planet, those here are bright, and, zooming in, there are several lines of evidence indicating that the dunes have become indurated, that is, hardened into cohesive sediment or even into sandstone rock. For example, the dune field at the southern edge is cut off by a step cliff, indicating erosion of hard material. Although fine scale ripples on the original dune surface are preserved, we also see large scale fluting from southwest to northeast, a common texture associated with wind-induced sand abrasion. How these dunes became indurated is unknown. One possibility is that this area of Mars was buried and then exhumed, a process that seems to have occurred many times in the Martian past over various areas of the planet. During burial, compaction and possibly ground water circulation would have indurated the dunes, leaving them as a hard sandstone that, when exhumed, was subsequently partially eroded. http://photojournal.jpl.nasa.gov/catalog/PIA18890

Expanded secondary craters in the Arcadia Planitia region, Mars: evidence for tens of Myr-old shallow subsurface ice

USGS Publications Warehouse

Viola, Donna; McEwen, Alfred S.; Dundas, Colin M.; Byrne, Shane

2015-01-01

A range of observations indicates widespread subsurface ice throughout the mid and high latitudes of Mars in the form of both pore-filling and excess ice. It is generally thought that this ice was recently emplaced and is not older than a hundred thousand to a few millions of years old based on ice stability and orbital-induced climate change. We analyze the distribution of subsurface ice in Arcadia Planitia, located in the northern mid latitudes, by mapping thermokarstically expanded secondary craters, providing additional evidence for extensive excess ice down to fairly low latitudes (less than 40°N). We further infer the minimum age of this subsurface ice based on the ages of the four primary craters that are thought to be the source of a large portion of these secondaries, which yields estimates on the order of tens of millions of years old – much more ancient than anticipated. This estimated ancient age suggests that ice can be preserved in the shallow subsurface for long periods of time, at least in some parts of Arcadia Planitia where expanded secondary craters are especially abundant. We estimate the amount of ice lost to sublimation during crater expansion based on measurements of expanded secondary craters in HiRISE Digital Terrain Models. The loss is equivalent to a volume of ice between ∼140 and 360 km3, which would correspond to a global layer of 1–2.5 mm thick. We further argue that much more ice (at least 6000 km3) is likely preserved beneath the un-cratered regions of Arcadia Planitia since significant loss of this excess ice would have caused extensive terrain dissection and the removal of the expanded secondary craters. Both the loss of ice due to secondary crater expansion and the presence of this ice today have implications for the martian climate.

Mud Volcanoes as Exploration Targets on Mars

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Oehler, Dorothy Z.

2010-01-01

Tens of thousands of high-albedo mounds occur across the southern part of the Acidalia impact basin on Mars. These structures have geologic, physical, mineralogic, and morphologic characteristics consistent with an origin from a sedimentary process similar to terrestrial mud volcanism. The potential for mud volcanism in the Northern Plains of Mars has been recognized for some time, with candidate mud volcanoes reported from Utopia, Isidis, northern Borealis, Scandia, and the Chryse-Acidalia region. We have proposed that the profusion of mounds in Acidalia is a consequence of this basin's unique geologic setting as the depocenter for the tune fraction of sediments delivered by the outflow channels from the highlands.

Geologic Map of the MTM -30262 and -30267 Quadrangles, Hadriaca Patera Region of Mars

USGS Publications Warehouse

Crown, David A.; Greeley, Ronald

2007-01-01

Introduction Mars Transverse Mercator (MTM) -30262 and -30267 quadrangles cover the summit region and east margin of Hadriaca Patera, one of the Martian volcanoes designated highland paterae. MTM -30262 quadrangle includes volcanic deposits from Hadriaca Patera and Tyrrhena Patera (summit northeast of map area) and floor deposits associated with the Dao and Niger Valles canyon systems (south of map area). MTM -30267 quadrangle is centered on the caldera of Hadriaca Patera. The highland paterae are among the oldest, central-vent volcanoes on Mars and exhibit evidence for explosive eruptions, which make a detailed study of their geology an important component in understanding the evolution of Martian volcanism. Photogeologic mapping at 1:500,000-scale from analysis of Viking Orbiter images complements volcanological studies of Hadriaca Patera, geologic investigations of the other highland paterae, and an analysis of the styles and evolution of volcanic activity east of Hellas Planitia in the ancient, cratered highlands of Mars. This photogeologic study is an extension of regional geologic mapping east of Hellas Planitia. The Martian highland paterae are low-relief, areally extensive volcanoes exhibiting central calderas and radial channels and ridges. Four of these volcanoes, Hadriaca, Tyrrhena, Amphitrites, and Peneus Paterae, are located in the ancient cratered terrains surrounding Hellas Planitia and are thought to be located on inferred impact basin rings or related fractures. Based on analyses of Mariner 9 images, Potter (1976), Peterson (1977), and King (1978) suggested that the highland paterae were shield volcanoes formed by eruptions of fluid lavas. Later studies noted morphologic similarities between the paterae and terrestrial ash shields and the lack of primary lava flow features on the flanks of the volcanoes. The degraded appearances of Hadriaca and Tyrrhena Paterae and the apparently easily eroded materials composing their low, broad shields further suggest that the highland paterae are composed predominantly of pyroclastic deposits. Analyses of eruption and flow processes indicate that the distribution of units at Hadriaca and Tyrrhena Paterae is consistent with emplacement by gravity-driven pyroclastic flows. Detailed geologic study of the summit caldera and flanks of Hadriaca Patera is essential to determine the types of volcanic materials exposed, the nature of the processes forming these deposits, and the role of volcanism in the evolution of the cratered highlands that are characteristic of the southern hemisphere of Mars.

Lunar and Planetary Science XXXV: Mars: Wind, Dust Sand, and Debris

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Mars: Wind, Dust Sand, and Debris" included: Mars Exploration Rovers: Laboratory Simulations of Aeolian Interactions; Thermal and Spectral Analysis of an Intracrater Dune Field in Amazonis Planitia; How High is that Dune? A Comparison of Methods Used to Constrain the Morphometry of Aeolian Bedforms on Mars; Dust Devils on Mars: Scaling of Dust Flux Based on Laboratory Simulations; A Close Encounter with a Terrestrial Dust Devil; Interpretation of Wind Direction from Eolian Features: Herschel Crater, Mars Erosion Rates at the Viking 2 Landing Site; Mars Dust: Characterization of Particle Size and Electrostatic Charge Distributions; Simple Non-fluvial Models of Planetary Surface Modification, with Application to Mars; Comparison of Geomorphically Determined Winds with a General Circulation Model: Herschel Crater, Mars; Analysis of Martian Debris Aprons in Eastern Hellas Using THEMIS; Origin of Martian Northern Hemisphere Mid-Latitude Lobate Debris Aprons; Debris Aprons in the Tempe/Mareotis Region of Mars;and Constraining Flow Dynamics of Mass Movements on Earth and Mars.

Squiggles in Hellas Planitia

NASA Image and Video Library

2017-10-25

At around 2,200 kilometers in diameter, Hellas Planitia is the largest visible impact basin in the Solar System, and hosts the lowest elevations on Mars' surface as well as a variety of landscapes. This image from NASA's Mars Reconnaisance Orbiter (MRO) covers a small central portion of the basin and shows a dune field with lots of dust devil trails. In the middle, we see what appears to be long and straight "scratch marks" running down the southeast (bottom-right) facing dune slopes. If we look closer, we can see these scratch marks actually squiggle back and forth on their way down the dune. These scratch marks are linear gullies. Just like on Earth, high-latitude regions on Mars are covered with frost in the winter. However, the winter frost on Mars is made of carbon dioxide ice (dry ice) instead of water ice. We believe linear gullies are the result of this dry ice breaking apart into blocks, which then slide or roll down warmer sandy slopes, sublimating and carving as they go. The linear gullies exhibit exceptional sinuosity (the squiggle pattern) and we believe this to be the result of repeated movement of dry ice blocks in the same path, possibly in combination with different hardness or flow resistance of the sand within the dune slopes. Determining the specific process that causes the formation and evolution of sinuosity in linear gullies is a question scientists are still trying to answer. What do you think causes the squiggles? https://photojournal.jpl.nasa.gov/catalog/PIA22052

MOLA Topographic Evidence for a Massive Noachian Ocean on Mars

NASA Technical Reports Server (NTRS)

Parker, T. J.; Grant, J. A.; Anderson, F. S.; Franklin, B. J.

2002-01-01

If the topographic terraces described are coastal, an ocean upwards of 5 to 7 km deep would be required by the maximum elevation of terraces identified south of Elysium Planitia. The highest terrace identified to date is at 2200 m elevation. Additional information is contained in the original extended abstract.

Clastic polygonal networks around Lyot crater, Mars: Possible formation mechanisms from morphometric analysis

NASA Astrophysics Data System (ADS)

Brooker, L. M.; Balme, M. R.; Conway, S. J.; Hagermann, A.; Barrett, A. M.; Collins, G. S.; Soare, R. J.

2018-03-01

Polygonal networks of patterned ground are a common feature in cold-climate environments. They can form through the thermal contraction of ice-cemented sediment (i.e. formed from fractures), or the freezing and thawing of ground ice (i.e. formed by patterns of clasts, or ground deformation). The characteristics of these landforms provide information about environmental conditions. Analogous polygonal forms have been observed on Mars leading to inferences about environmental conditions. We have identified clastic polygonal features located around Lyot crater, Mars (50°N, 30°E). These polygons are unusually large (>100 m diameter) compared to terrestrial clastic polygons, and contain very large clasts, some of which are up to 15 metres in diameter. The polygons are distributed in a wide arc around the eastern side of Lyot crater, at a consistent distance from the crater rim. Using high-resolution imaging data, we digitised these features to extract morphological information. These data are compared to existing terrestrial and Martian polygon data to look for similarities and differences and to inform hypotheses concerning possible formation mechanisms. Our results show the clastic polygons do not have any morphometric features that indicate they are similar to terrestrial sorted, clastic polygons formed by freeze-thaw processes. They are too large, do not show the expected variation in form with slope, and have clasts that do not scale in size with polygon diameter. However, the clastic networks are similar in network morphology to thermal contraction cracks, and there is a potential direct Martian analogue in a sub-type of thermal contraction polygons located in Utopia Planitia. Based upon our observations, we reject the hypothesis that polygons located around Lyot formed as freeze-thaw polygons and instead an alternative mechanism is put forward: they result from the infilling of earlier thermal contraction cracks by wind-blown material, which then became compressed and/or cemented resulting in a resistant fill. Erosion then leads to preservation of these polygons in positive relief, while later weathering results in the fracturing of the fill material to form angular clasts. These results suggest that there was an extensive area of ice-rich terrain, the extent of which is linked to ejecta from Lyot crater.

Location and Geologic Setting for the Three U.S. Mars Landers

NASA Technical Reports Server (NTRS)

Parker, T. J.; Kirk, R. L.

1999-01-01

Super resolution of the horizon at both Viking landing sites has revealed "new" features we use for triangulation, similar to the approach used during the Mars Pathfinder Mission. We propose alternative landing site locations for both landers for which we believe the confidence is very high. Super resolution of VL-1 images also reveals some of the drift material at the site to consist of gravel-size deposits. Since our proposed location for VL-2 is NOT on the Mie ejecta blanket, the blocky surface around the lander may represent the meter-scale texture of "smooth palins" in the region. The Viking Lander panchromatic images typically offer more repeat coverage than does the IMP on Mars Pathfinder, due to the longer duration of these landed missions. Sub-pixel offsets, necessary for super resolution to work, appear to be attributable to thermal effects on the lander and settling of the lander over time. Due to the greater repeat coverage (particularly in the near and mid-fields) and all-panchromatic images, the gain in resolution by super resolution processing is better for Viking than it is with most IMP image sequences. This enhances the study of textural details near the lander and enables the identification rock and surface textures at greater distances from the lander. Discernment of stereo in super resolution im-ages is possible to great distances from the lander, but is limited by the non-rotating baseline between the two cameras and the shorter height of the cameras above the ground compared to IMP. With super resolution, details of horizon features, such as blockiness and crater rim shapes, may be better correlated with Orbiter images. A number of horizon features - craters and ridges - were identified at VL-1 during the misison, and a few hils and subtle ridges were identified at VL-2. We have added a few "new" horizon features for triangulation at the VL-2 landing site in Utopia Planitia. These features were used for independent triangulation with features visible in Viking Orbiter and MGS MOC images, though the actual location of VL-1 lies in a data dropout in the MOC image of the area. Additional information is contained in the original extended abstract.

Selection of the Mars Exploration Rover landing sites

NASA Astrophysics Data System (ADS)

Golombek, M. P.; Grant, J. A.; Parker, T. J.; Kass, D. M.; Crisp, J. A.; Squyres, S. W.; Haldemann, A. F. C.; Adler, M.; Lee, W. J.; Bridges, N. T.; Arvidson, R. E.; Carr, M. H.; Kirk, R. L.; Knocke, P. C.; Roncoli, R. B.; Weitz, C. M.; Schofield, J. T.; Zurek, R. W.; Christensen, P. R.; Fergason, R. L.; Anderson, F. S.; Rice, J. W.

2003-12-01

The selection of Meridiani Planum and Gusev crater as the Mars Exploration Rover landing sites took over 2 years, involved broad participation of the science community via four open workshops, and narrowed an initial ~155 potential sites (80-300 × 30 km) to four finalists based on science and safety. Engineering constraints important to the selection included (1) latitude (10°N-15°S) for maximum solar power, (2) elevation (less than -1.3 km) for sufficient atmosphere to slow the lander, (3) low horizontal winds, shear, and turbulence in the last few kilometers to minimize horizontal velocity, (4) low 10-m-scale slopes to reduce airbag spin-up and bounce, (5) moderate rock abundance to reduce abrasion or strokeout of the airbags, and (6) a radar-reflective, load-bearing, and trafficable surface safe for landing and roving that is not dominated by fine-grained dust. The evaluation of sites utilized existing as well as targeted orbital information acquired from the Mars Global Surveyor and Mars Odyssey. Three of the final four landing sites show strong evidence for surface processes involving water and appear capable of addressing the science objectives of the missions, which are to determine the aqueous, climatic, and geologic history of sites on Mars where conditions may have been favorable to the preservation of evidence of possible prebiotic or biotic processes. The evaluation of science criteria placed Meridiani and Gusev as the highest-priority sites. The evaluation of the three most critical safety criteria (10-m-scale slopes, rocks, and winds) and landing simulation results indicated that Meridiani and Elysium Planitia are the safest sites, followed by Gusev and Isidis Planitia.

Selection of the Mars Exploration Rover landing sites

USGS Publications Warehouse

Golombek, M.P.; Grant, J. A.; Parker, T.J.; Kass, D.M.; Crisp, J.A.; Squyres, S. W.; Haldemann, A.F.C.; Adler, M.; Lee, W.J.; Bridges, N.T.; Arvidson, R. E.; Carr, M.H.; Kirk, R.L.; Knocke, P.C.; Roncoli, R.B.; Weitz, C.M.; Schofield, J.T.; Zurek, R.W.; Christensen, P.R.; Fergason, R.L.; Anderson, F.S.; Rice, J. W.

2003-01-01

The selection of Meridiani Planum and Gusev crater as the Mars Exploration Rover landing sites took over 2 years, involved broad participation of the science community via four open workshops, and narrowed an initial ???155 potential sites (80-300 ?? 30 km) to four finalists based on science and safety. Engineering constraints important to the selection included (1) latitude (10??N- 15??S) for maximum solar power, (2) elevation (less than - 1.3 km) for sufficient atmosphere to slow the lander, (3) low horizontal winds, shear, and turbulence in the last few kilometers to minimize horizontal velocity, (4) low 10-m-scale slopes to reduce airbag spin-up and bounce, (5) moderate rock abundance to reduce abrasion or strokeout of the airbags, and (6) a radar-reflective, load-bearing, and trafficable surface safe for landing and roving that is not dominated by fine-grained dust. The evaluation of sites utilized existing as well as targeted orbital information acquired from the Mars Global Surveyor and Mars Odyssey. Three of the final four landing sites show strong evidence for surface processes involving water and appear capable of addressing the science objectives of the missions, which are to determine the aqueous, climatic, and geologic history of sites on Mars where conditions may have been favorable to the preservation of evidence of possible prebiotic or biotic processes. The evaluation of science criteria placed Meridiani and Gusev as the highest-priority sites. The evaluation of the three most critical safety criteria (10-m-scale slopes, rocks, and winds) and landing simulation results indicated that Meridiani and Elysium Planitia are the safest sites, followed by Gusev and Isidis Planitia. Copyright 2003 by the American Geophysical Union.

Topographic Map of Chryse Planitia with Location of Possible Buried Basin

NASA Technical Reports Server (NTRS)

2005-01-01

This topographic map, based on data from the Mars Orbiter Laser Altimeter, shows the ground track of the 1,892nd and the 1,903rd orbits of Mars Express and the arc structures detected by that orbiter's Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS). The arc structures are interpreted to be part of a buried impact basin about 250 kilometers (155 miles) in diameter.

The topographic relief represented in the image is 1 kilometer (0.6 mile), from low (purple) to high (red). The projected arcs are shown in red for orbit 1892 and white for orbit 1903. There is no obvious feature in the surface topography that corresponds to the buried feature identified with MARSIS data.

NASA and the Italian Space Agency jointly funded the MARSIS instrument on the European Space Agency's Mars Express orbiter. The Mars Orbiter Laser Altimeter is an instrument on NASA's Mars Global Surveyor orbiter.

Low-Centred Polygons and Alas-Like Basins as Geological Markers of Warming Trends Late in Mars' History

NASA Astrophysics Data System (ADS)

Soare, R. J.; Conway, S. J.; Godin, E.; Osinski, G.; Hawkswell, J.; Bina, A.

2017-12-01

Expansive assemblages of low/high centred (ice-wedge) polygons and (polygonised) flat-floored thermokarst-basins (alases) are ubiquitous on Earth where the permafrost is continuous, metres to decametres-thick and ice rich, i.e. the Tuktoyaktuk Coastlands of northern Canada and the Yamal Peninsula of eastern Russia. These assemblages are geological bellwethers of transient and on occasion, long-term rises of sub-aerial and thaw-generating mean temperatures, for two principal reasons. First, high-centred (ice-wedge) polygons evolve from low-centred (ice-wedge) polygons when ice wedges that have aggraded and uplift overlying sediments above the elevation datum at the polygon centres, degrade, by thaw, and induce the loss of elevation below that datum. Second, thermokarst terrain comprises sediments whose pore volume is exceeded by the presence of water ice. A thermokarst basin (an alas) forms if and only when this ice undergoes thermal destabilisation and where thaw-generated meltwater is lost by evaporation or drainage. Spatially-associated and morphologically-similar assemblages of polygons and basins are commonplace throughout the mid-latitudes of eastern Utopia Planitia (UP), Mars. Under current conditions of extreme aridity, low atmospheric-pressure and frigid mean-temperatures, the widespread formation of ice-rich terrain by freeze-thaw cycling, let alone of near-surface ice-wedges and/or thermokarst basins, seems implausible. Against this environmental backdrop, sublimation seemingly stands alone in being able to revise ice-rich landscapes. However, multiple strands of data point to the possible periglacial-assemblages (PPAs) being youthful but not current in their formation. First, the sub-regional and dark-toned terrain incised by the PPAs is cratered more densely than would be expected. Second, the PPAs reside at a lower relative and absolute elevation than a light-toned and region-wide latitude-dependent mantle that is generally thought to be very recent in origin. These strands and others point to a earlier period in the geological history of UP, perhaps in conjunction with shifts in obliquity and eccentricity, when liquid-water would have been stable enough to sustain freeze-thaw cycling, wet periglacial processes and, derivatively, the development of the PPAs.

Landing Area Narrowed for 2016 InSight Mission to Mars

NASA Image and Video Library

2013-09-04

The process of selecting a site for NASA's next landing on Mars, planned for September 2016, has narrowed to four semifinalist sites located close together in the Elysium Planitia region of Mars. The mission known by the acronym InSight will study the Red Planet's interior, rather than surface features, to advance understanding of the processes that formed and shaped the rocky planets of the inner solar system, including Earth. The location of the cluster of semifinalist landing sites for InSight is indicated on this near-global topographic map of Mars, which also indicates landing sites of current and past NASA missions to the surface of Mars. The mission's full name is Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport. The location of Elysium Planitia close to the Martian equator meets an engineering requirement for the stationary InSight lander to receive adequate solar irradiation year-round on its photovoltaic array. The location also meets an engineering constraint for low elevation, optimizing the amount of atmosphere the spacecraft can use for deceleration during its descent to the surface. The number of candidate landing sites for InSight was trimmed from 22 down to four in August 2013. This down-selection facilitates focusing the efforts to further evaluate the four sites. Cameras on NASA's Mars Reconnaissance Orbiter will be used to gather more information about them before the final selection. The topographic map uses data from the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor spacecraft. The color coding on this map indicates elevation relative to a reference datum, since Mars has no "sea level." The lowest elevations are presented as dark blue; the highest as white. The difference between green and orange in the color coding is about 2.5 miles (4 kilometers) vertically. Note: After thorough examination, NASA managers have decided to suspend the planned March 2016 launch of the Interior Exploration using Seismic Investigations Geodesy and Heat Transport (InSight) mission. The decision follows unsuccessful attempts to repair a leak in a section of the prime instrument in the science payload. http://photojournal.jpl.nasa.gov/catalog/PIA17357

Origin of Bright Dust Devil Track on Mars

NASA Astrophysics Data System (ADS)

Hamada, K.; Kurita, K.; Nishizawa, S.

2017-09-01

we performed detailed in- vestigation on DDT in specific regions where BDDT are abundantly observed; in and around Schiaparelli Crater and Amazonis Planitia by using CTX images. We found 1) BDDT are confined to localized regions while DDDT are distributed broadly in these regions, 2) in 10km scale both BDDT and DDDT exhibit dom- inant orientations, 3) existence of banded DDT.

Acidalia and Chryse Plains, Mars

NASA Image and Video Library

2000-06-14

Somewhere down there sits the Mars Pathfinder lander and Sojourner rover. This Mars Global Surveyor Mars Orbiter Camera view of the red planet shows the region that includes Ares Vallis and the Chryse Plains upon which both Mars Pathfinder and the Viking 1 landed in 1997 and 1976, respectively. Acidalia Planitia is the dark surface that dominates the center left. The Pathfinder site is immediately south of Acidalia, just left of center in this view. Also shown--the north polar cap is at the top, and Arabia Terra and Sinus Meridiani are to the right. The bluish-white features are clouds. This is a color composite of 9 red and 9 blue image strips taken by the Mars Global Surveyor Mars Orbiter Camera on 9 successive orbits from pole-to-pole during the calibration phase of the mission in March 1999. The color is computer-enhanced and is not shown as it would actually appear to the human eye. http://photojournal.jpl.nasa.gov/catalog/PIA02000

Sedimentary history and mass flow structures of Chryse and Acidalia Planitiae, Mars

USGS Publications Warehouse

Tanaka, K.L.

1997-01-01

Geologic mapping and crater counting in Chryse and Acidalia Planitiae (GAP) reveal five major sedimentary deposits of Hesperian to Early Amazonian age, including (1) a mass flow deposited during the Early Hesperian near Deuteronilus Mensae (northeast of the map region) that may have resulted from the carving of Kasei Valles, >3000 km southwest of the exposed part of the deposit; (2) knobby plains material consisting of channel (likely; from Simud and Tiu Valles and possibly Ares and Shalbatana Valles) and mass-wasting deposits in central and eastern CAP; (3) material largely from Maja and Ares Valles emplaced in at least western and southern CAP (outcrops in southern Chryse Planitia developed thermokarst); (4) a thin mass flow covering much of southern Chryse Planitia that emanated from Simud and Tiu Valles; and (5) a thick, extensive (perhaps >3500 km across) mass flow deposit in central and northern CAP derived from accumulation and backflow of the preceding thin mass flow or perhaps melting of polar deposits. Other possible deposits may not be recognizable owing to burial by younger materials or a lack of morphologic signature. Various associated landforms appear to be consistent with the mass flow interpretations, including lobate and linear scarps along deposit edges, fractures related to desiccation of thick sediments, troughs, and ridges near the edges of the deposit indicative of secondary mass movement and deformation, pitted domes and fissure-fed flows possibly formed by sedimentary (mud) eruptions, and longitudinal channel grooves perhaps formed by roller vortices. No convincing evidence for paleoshorelines or stagnant ice sheets is found in CAP. These findings suggest that mass flow and hyperconcentrated flooding may have been the predominant processes of outflow-channel dissection in CAP. Elsewhere in the northern plains, similar landforms are prevalent. The mass flow interpretation does not require either multiple episodes of extraordinarily high water-discharge rates achieved by freeing huge volumes of water from the crust, repetitive recycling of immense volumes of water into highland aquifers at the heads of Chryse channels, or profound climate change. Mars Pathfinder will most likely land on and inspect the surface of the thin mass flow that originated from the canyons of Simud and Tiu Valles.

Origin of giant Martian polygons

NASA Technical Reports Server (NTRS)

Mcgill, George E.; Hills, L. S.

1992-01-01

Extensive areas of the Martian northern plains in Utopia and Acidalia planitiae are characterized by 'polygonal terrane'. Polygonal terrane consists of material cut by complex troughs defining a pattern resembling mudcracks, columnar joints, or frost-wedge polygons on earth. However, the Martian polygons are orders of magnitude larger than these potential earth analogues, leading to severe mechanical difficulties for genetic models based on simple analogy arguments. Plate-bending and finite element models indicate that shrinkage of desiccating sediment or cooling volcanics accompanied by differential compaction over buried topography can account for the stresses responsible for polygon troughs as well as the large size of the polygons. Although trough widths and depths relate primarily to shrinkage, the large scale of the polygonl pattern relates to the spacing between topographic elevations on the surface buried beneath polygonal terrane material. Geological relationships favor a sedimentary origin for polygonal terrane material, but our model is not dependent on the specific genesis. Our analysis also suggests that the polygons must have formed at a geologically rapid rate.

Some consequences of a liquid water saturated regolith in early Martian history

NASA Technical Reports Server (NTRS)

Fuller, A. O.; Hargraves, R. B.

1978-01-01

Flooding of low-lying areas of the Martian regolith may have occurred early in the planet's history when a comparatively dense primitive atmosphere existed. If this model is valid, the following are some pedogenic and mineralogical consequences to be expected. Fluctuation of the water table in response to any seasonal or longer term causes would have resulted in precipitation of ferric oxyhydroxides with the development of a vesicular duricrust (or hardpan). Disruption of such a crust by scarp undercutting or frost heaving accompanied by wind deflation of fines could account for the boulders visible on Utopia Planitia in the vicinity of the second Viking lander site. Laboratory and field evidence on earth suggests that under weakly oxidizing conditions lepidocrocite (rather than goethite) would have preferentially formed in the Martian regolith from the weathering of ferrous silicates, accompanied by montmorillonite, nontronite, and cronstedtite. Maghemite may have formed as a low-temperature dehydrate of lepidocrocite or directly from ferrous precursors.

Side-by-Side

NASA Technical Reports Server (NTRS)

2006-01-01

18 May 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows neighboring networks of gullies in the northwest wall of a south middle-latitude crater west of Hellas Planitia. The faint crisscrossing streaks, also observed on the wall of the crater, are evidence of passing dust devils, a common phenomenon in this region. The gullies might have formed by erosion caused by running water, mixed with debris.

Location near: 16.4oN, 92.6oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

Topographic map of the western region of Dao Vallis in Hellas Planitia, Mars; MTM 500k -40/082E OMKT

USGS Publications Warehouse

Rosiek, Mark R.; Redding, Bonnie L.; Galuszka, Donna M.

2006-01-01

This map, compiled photogrammetrically from Viking Orbiter stereo image pairs, is part of a series of topographic maps of areas of special scientific interest on Mars. Contours were derived from a digital terrain model (DTM) compiled on a digital photogrammetric workstation using Viking Orbiter stereo image pairs with orientation parameters derived from an analytic aerotriangulation. The image base for this map employs Viking Orbiter images from orbits 406 and 363. An orthophotomosaic was created on the digital photogrammetric workstation using the DTM compiled from stereo models.

Valles Marineris Hemisphere

NASA Image and Video Library

1996-06-03

Mosaic composed of 102 Viking Orbiter images of Mars, covering nearly a full hemisphere of the planet (approximate latitude -55 to 60 degrees, longitude 30 to 130 degrees). The mosaic is in a point-perspective projection with a scale of about 1 km/pixel. The color variations have been enhanced by a factor of about two, and the large-scale brightness variations (mostly due to sun-angle variations) have been normalized by large-scale filtering. The center of the scene shows the entire Valles Marineris canyon system, over 3,000 km long and up to 8 km deep, extending from Noctis Labyrinthus, the arcuate system of graben to the west, to the chaotic terrain to the east. Bright white layers of material in the eastern canyons may consist of carbonates deposited in ancient lakes. Huge ancient river channels begin from the chaotic terrain and from north-central canyons and run north. Many of the channels flowed into a basin called Acidalia Planitia, which is the dark area in the extreme north of this picture. The Viking 1 landing site (Mutch Memorial Station) is located in Chryse Planitia, south of Acidalia Planitia. The three Tharsis volcanoes (dark red spots), each about 25 km high, are visible to the west. The large crater with two prominent rings located at the bottom of this image is named Lowell, after the Flagstaff astronomer. The images were acquired by Viking Orbiter 1 in 1980 during early northern summer on Mars (Ls = 70 degrees); the atmosphere was relatively dust-free. A variety of clouds appear as bright blue streaks and hazes, and probably consist of water ice. Long, linear clouds north of central Valles Marineris appear to emanate from impact craters. http://photojournal.jpl.nasa.gov/catalog/PIA00003

Escape from Mars

NASA Image and Video Library

2017-07-10

This image from NASA's Mars Reconnaissance Orbiter shows one of millions of small (10s of meters in diameter) craters and their ejecta material that dot the Elysium Planitia region of Mars. The small craters were likely formed when high-speed blocks of rock were thrown out by a much larger impact (about 10-kilometers in diameter) and fell back to the ground. Some of these blocks may actually escape Mars, which is how we get samples in the form of meteorites that fall to Earth. Other ejected blocks have insufficient velocity, or the wrong trajectory, to escape the Red Planet. As such, when one of these high-speed blocks impacts the surface, it makes what is called a "secondary" crater. These secondaries can form dense "chains" or "rays," which are radial to the crater that formed them. https://photojournal.jpl.nasa.gov/catalog/PIA21769

Hubble Takes Mars Portrait Near Close Approach

NASA Image and Video Library

2017-12-08

Mars is looking mighty fine in this portrait nabbed by the Hubble Space Telescope on a near close approach! Read more: go.nasa.gov/1rWYiBT The Hubble Space Telescope is more well known for its picturesque views of nebulae and galaxies, but it's also useful for studying our own planets, including Mars. Hubble imaged Mars on May 12, 2016 - ten days before Mars would be on the exact opposite side of the Earth from the Sun. Bright, frosty polar caps, and clouds above a vivid, rust-colored landscape reveal Mars as a dynamic seasonal planet in this NASA Hubble Space Telescope view taken on May 12, 2016, when Mars was 50 million miles from Earth. The Hubble image reveals details as small as 20 to 30 miles across. The large, dark region at far right is Syrtis Major Planitia, one of the first features identified on the surface of the planet by seventeenth-century observers. Christiaan Huygens used this feature to measure the rotation rate of Mars. (A Martian day is about 24 hours and 37 minutes.) Today we know that Syrtis Major is an ancient, inactive shield volcano. Late-afternoon clouds surround its summit in this view. A large oval feature to the south of Syrtis Major is the bright Hellas Planitia basin. About 1,100 miles across and nearly five miles deep, it was formed about 3.5 billion years ago by an asteroid impact. The orange area in the center of the image is Arabia Terra, a vast upland region in northern Mars that covers about 2,800 miles. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest terrains on the planet. Dried river canyons (too small to be seen here) wind through the region and empty into the large northern lowlands. Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (ASU), and M. Wolff (Space Science Institute) #nasagoddard #mars #hubble #space NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Volcanic flows versus water- and ice-related outburst deposits in eastern Hellas: A comparison

NASA Astrophysics Data System (ADS)

Voelker, M.; Hauber, E.; Stephan, K.; Jaumann, R.

2018-06-01

Hellas Planitia is one of the major topographic sinks on Mars for the deposition of any kind of sediments. We report on our observations of sheet deposits in the eastern part of the basin that are apparently related to the Dao Vallis outflow channel. The deposits have lobate flow fronts and a thickness of a few decameters. Despite their generally smooth surface, some distinctive textures and patterns can be identified, such as longitudinal lineations, distributive channels, and polygons. We compared these deposits to other sheet deposits on Mars and tested three hypotheses of their origin: volcanic flows as well as water- and ice-related mass wastings. Despite some similarities to volcanic sheet flows on Mars, we found several morphological characteristics that are not known for sheet lava flows; for example conically arranged lineations and channel systems very similar to fluvial incisions. We also reject an ice-related formation similar to terrestrial rock-ice avalanches, as there is no sufficient relief energy to explain their extent and location. A water-related origin appears most consistent with our observations, and we favor an emplacement by fluvially-driven mass wasting processes, e.g., debris flows. Assuming a water-related origin, we calculated the amount of water that would be required to deposit such large sedimentary bodies for different flow types. Our calculations show a large range of possible water volumes, from 64 to 2,042 km³, depending on the specific flow mechanism. The close link to Dao Vallis makes these deposits a unique place to study the deposition of outflow channel sediments, as the deposits of other outflow channels on Mars, such as those around Chryse Planitia, are mostly buried by younger sediments and volcanic flows.

A 3-D Look at Wind-Sculpted Ridges in Aeolis

NASA Technical Reports Server (NTRS)

2000-01-01

Layers of bedrock etched by wind to form sharp, elongated ridges known to geomorphologists as yardangs are commonplace in the southern Elysium Planitia/southern Amazonis region of Mars. The ridges shown in this 3-D composite of two overlapping Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images occur in the eastern Aeolis region of southern Elysium Planitia near 2.3oS, 206.8oW. To view the picture in stereo, you need red-blue 3-D glasses (red filter over the left eye, blue over the right). For wind to erode bedrock into the patterns seen here, the rock usually must consist of something that is fine-grained and of nearly uniform grain size, such as sand. It must also be relatively easy to erode. For decades, most Mars researchers have interpreted these materials to be eroded deposits of volcanic ash. Nothing in the new picture shown here can support nor refute this earlier speculation. The entire area is mantled by light-toned dust. Small landslides within this thin dust layer form dark streaks on some of the steeper slopes in this picture (for more examples and explanations for these streaks, see previous web pages listed below).

The stereo (3-D) picture was compiled using an off-nadir view taken by the MOC during the Aerobrake-1 subphase of the mission in January 1998 with a nadir (straight-down-looking) view acquired in October 2000. The total area shown is about 6.7 kilometers (4.2 miles) wide by 2.5 kilometers (1.5 miles) high and is illuminated by sunlight from the upper right. The relief in the stereo image is quite exaggerated: the ridges are between about 50 and 100 meters (about 165-330 feet) high. North is toward the lower right.

Expanded Craters on Mars: Implications for Shallow, Mid-latitude Excess Ice

NASA Astrophysics Data System (ADS)

Viola, Donna

Understanding the age and distribution of shallow ice on Mars is valuable for interpreting past and present climate conditions, and has implications on habitability and future in situ resource utilization. Many ice-related features, such as lobate debris aprons and concentric crater fill, have been studied using a range of remote sensing techniques. Here, I explore the distribution of expanded craters, a form of sublimation thermokarst where shallow, excess ice has been destabilized and sublimated following an impact event. This leads to the collapse of the overlying dry regolith to produce the appearance of diameter widening. The modern presence of these features suggests that excess ice has remained preserved in the terrain immediately surrounding the craters since the time of their formation in order to maintain the surface. High-resolution imagery is ideal for observing thermokarst features, and much of the work described here will utilize data from the Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter (MRO). Expanded craters tend to be found in clusters that emanate radially from at least four primary craters in Arcadia Planitia, and are interpreted as secondary craters that formed nearly simultaneously with their primaries. Crater age dates of the primaries indicate that the expanded secondaries, as well as the ice layer into which they impacted, must be at least tens of millions of years old. Older double-layer ejecta craters in Arcadia Planitia commonly have expanded craters superposed on their ejecta - and they tend to be more expanded (with larger diameters) in the inner ejecta layer. This has implications on the formation mechanisms for craters with this unique ejecta morphology. Finally, I explore the distribution of expanded craters south of Arcadia Planitia and across the southern mid-latitudes, along with scalloped depressions (another form of sublimation thermokarst), in order to identify the modern excess ice boundary in this region and any longitudinal variations. This study identifies some potential low-latitude locations with patchy excess ice, possibly preserved during a past climate. Through these studies, I will infer regions that contain abundant ice today and consider the implications that this ice has on both the martian climate and future exploration.

Possible sea sediments due to glaciofluvial activity in Elysium Planitia, Mars

NASA Astrophysics Data System (ADS)

Nussbaumer, J.

Observations of fluvial morphologies in southern Elysium Planitia strongly supports the hypothesis that water substantially affected this region during the relatively recent geologic past. As of yet, however, the extent of a standing body of water has been speculative. The observation of zig-zag features potentially analogous to those observed near the Wadden Sea on Earth [see 1] may help show in more detail the origin, activity, and fate of water in this region of Mars. These terrestrial analogs could constrain environmental scenarios concerning the formation of these features. We present a geomorphologic map of central Elysium Planitia, that aids in our interpretation of potentially site-specific depositional/erosional morphologies. Positive relief zig-zag features within the Medusae Fossae Formation (Themis Image V05875001) resemble similar structures on Earth observed at shorelines of flat regions. Glaciofluvial activity is indicated by linear features resembling straight glacial flutings, which could form aeolian yardangs subsequently. The flutings are associated with branches of inverted fluvial channels (Images Themis V05588002, MOC e1800307). Their excavated positive relief (height ~40 m) indicates, that the adjacent material was eroded by sublimation or aeolian activity. The channels possibly resemble ice marginal channels. A high resolution Digital Terrain Model of one of the channels suggests, that one channel is possibly running upslope. Fluvial processes could have operated at one location at one time, and glacial processes at another location at another time [2]. A glacial drainage system [see 3] is a possible terrestrial analog for one inverted fluvial channel on Mars (Themis Image V05875001). Flutings occur on the foreland of many glaciers and their length may provide important evidence for rapid advance over substantial distances. Flutings are the product of subglacial erosion and transport processes [4]. By assigning the different environmental conditions to their geographic and stratigraphic positions, we intend to develop a geologic history of the central Elysium region. Ackowledgements for helpful contributions: D. Burr, J. Skinner, R. Williams References: [1] Tomei, K. (2004), Scriptum Publishers, 312 pp. [2] Burr et al. (2006) LPS XXXVII, #1367. [3] Evans, D. (2005), Hodder Arnold, 544pp. [4] Sharp M. J. (1984) Journal of Glaciology 82-93.

Lunar and Planetary Science XXXVI, Part 20

NASA Technical Reports Server (NTRS)

2005-01-01

The topics include: 1) Virtual Reality Technology as a Tool to Enhance Collaboration Between Space Exploration and Public Outreach: The Case Using the Mars Exploration Rover Images; 2) Atmospheric Electron-induced X-Ray Spectrometer (AEXS) Instrument Development; 3) Impact of Low Thermal Conductivity Layers on the Bulk Conductivity of a Martian Crustal Column; 4) Impacting Classroom Teachers Through Long-Term Professional Development; 5) Oxygen, Ca, and Ti Isotopic Compositions of Hibonite-bearing Inclusions; 6) Phenomenological Excitation Functions of Xe Isotopes with Protons on Nuclei of Cs, La and Ce; 7) Double-Diffusive Convection and Other Modes of Salinity-modulated Heat and Material Transport in Europa s Ocean; 8) Slope Morphologies of the Hellas Mensae Constructs, Eastern Hellas Planitia, Mars; 9) Development of Polygonal Thermal Contraction Patterns in a South Polar Trough, Mars 3 Years of Observations; 10) Martian Relevance of Dehydration and Rehydration in the Mg-Sulfate System; 11) Formation of Martian Volcanic Provinces by Lower Mantle Flushing? 12) Can Glasses Help Us to Unravel the Origin of Barred Olivine Chondrules? 13) Loki Patera: A Magma Sea Story; 14) Compositions of Partly Altered Olivine and Replacement Serpentine in the CM2 Chondrite QUE93005; 15) Model of Light Scattering by Lunar Regolith at Moderate Phase Angles: New Results; 16) Radiation Resistance of a Silicone Polymer Grease Based Regolith Collector for the HERA Near-Earth Asteroid Sample Return Mission; 17) Analysis of the Tectonic Lineaments in the Ganiki Planitia (V14) Quadrangle, Venus; 18) Nanometer-sized Diamonds from AGB Stars; 19) Quantifying Exact Motions Along Lineaments on Europa; 20) Geometry of Thrust Faults Beneath Amenthes Rupes, Mars; 21) Mapping of the Physical Characteristics and Mineral Composition of a Superficial Layer of the Moon or Mars and Ultra-Violet Polarimetry from the Orbital Station; 22) Negative Searches for Evidence of Aqueous Alteration on Asteroid Surfaces; 23) What Processes Have Shaped Basalt Boulders on Earth and Mars? Studies of Feature Persistence Using Facet Mapping and Fractal Analysis; 24) The Popigai Fluidizites: Dense Water Inclusions in Lechatelierite; Evidence for Shock-generated Carbonate and Hydrous Silicate Melts; 25) Missing Xenon Problem and Climate of the Early Earth; and 26) More on Magnetic Spectra from Correlated Crustal Sources on Mars

Martian subsurface properties and crater formation processes inferred from fresh impact crater geometries

NASA Astrophysics Data System (ADS)

Stewart, Sarah T.; Valiant, Gregory J.

2006-10-01

The geometry of simple impact craters reflects the properties of the target materials, and the diverse range of fluidized morphologies observed in Martian ejecta blankets are controlled by the near-surface composition and the climate at the time of impact. Using the Mars Orbiter Laser Altimeter (MOLA) data set, quantitative information about the strength of the upper crust and the dynamics of Martian ejecta blankets may be derived from crater geometry measurements. Here, we present the results from geometrical measurements of fresh craters 3-50 km in rim diameter in selected highland (Lunae and Solis Plana) and lowland (Acidalia, Isidis, and Utopia Planitiae) terrains. We find large, resolved differences between the geometrical properties of the freshest highland and lowland craters. Simple lowland craters are 1.5-2.0 times deeper (≥5σo difference) with >50% larger cavities (≥2σo) compared to highland craters of the same diameter. Rim heights and the volume of material above the preimpact surface are slightly greater in the lowlands over most of the size range studied. The different shapes of simple highland and lowland craters indicate that the upper ˜6.5 km of the lowland study regions are significantly stronger than the upper crust of the highland plateaus. Lowland craters collapse to final volumes of 45-70% of their transient cavity volumes, while highland craters preserve only 25-50%. The effective yield strength of the upper crust in the lowland regions falls in the range of competent rock, approximately 9-12 MPa, and the highland plateaus may be weaker by a factor of 2 or more, consistent with heavily fractured Noachian layered deposits. The measured volumes of continuous ejecta blankets and uplifted surface materials exceed the predictions from standard crater scaling relationships and Maxwell's Z model of crater excavation by a factor of 3. The excess volume of fluidized ejecta blankets on Mars cannot be explained by concentration of ejecta through nonballistic emplacement processes and/or bulking. The observations require a modification of the scaling laws and are well fit using a scaling factor of ˜1.4 between the transient crater surface diameter to the final crater rim diameter and excavation flow originating from one projectile diameter depth with Z = 2.7. The refined excavation model provides the first observationally constrained set of initial parameters for study of the formation of fluidized ejecta blankets on Mars.

The discovery of columnar jointing on Mars

USGS Publications Warehouse

Milazzo, M.P.; Keszthelyi, L.P.; Jaeger, W.L.; Rosiek, M.; Mattson, S.; Verba, C.; Beyer, R.A.; Geissler, P.E.; McEwen, A.S.; ,

2009-01-01

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 obliterated by the impact event were similarly jointed. We also see columns in the walls of other fresh craters in the nearby volcanic plains of Elysium Planitia–Amazonis Planitia, which include Marte Vallis, and in a well-preserved crater in northeast Hellas.

Ripples and Dunes

NASA Technical Reports Server (NTRS)

2006-01-01

27 May 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark sand dunes on the floor of an impact crater west of Hellas Planitia. Portions of the crater floor are exposed near the center and lower right corner of the image but, in general, the floor is covered by large, windblown ripples. The dark dune sand typically covers ripples, indicating that the dunes are younger and made of a more mobile material.

Location near: 43.7oS, 320.4oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

Frost in Charitum Montes

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-387, 10 June 2003

This is a Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle view of the Charitum Montes, south of Argyre Planitia, in early June 2003. The seasonal south polar frost cap, composed of carbon dioxide, has been retreating southward through this area since spring began a month ago. The bright features toward the bottom of this picture are surfaces covered by frost. The picture is located near 57oS, 43oW. North is at the top, south is at the bottom. Sunlight illuminates the scene from the upper left. The area shown is about 217 km (135 miles) wide.

System of gigantic valleys northwest of Tharsis, Mars: Latent catastrophic flooding, northwest watershed, and implications for northern plains ocean

USGS Publications Warehouse

Dohm, J.M.; Anderson, R.C.; Baker, V.R.; Ferris, J.C.; Hare, T.M.; Strom, R.G.; Rudd, L.P.; Rice, J. W.; Casavant, R.R.; Scott, D.H.

2000-01-01

Mars Orbiter Laser Altimeter (MOLA) reveals a system of gigantic valleys to the northwest of the huge martian shield volcano, Arsia Mons, in the western hemisphere of Mars. These newly identified northwestern slope valleys (NSVs) potentially signify previously undocumented martian catastrophic floods and may corroborate the northern ocean hypotheses. These features, which generally correspond spatially to gravity lows, were previously obscurred in Mariner and Viking Orbiter imagery by veneers of materials, including volcanic lava flows and air fall deposits. Geologic investigations of the Tharsis region suggest that the NSVs were mainly carved prior to the construction of Arsia Mons and its associated Late Hesperian and Amazonian age lava flows, concurrent with the early development of the outflow channels that debouch into Chryse Planitia.

Scientific rationale for selecting northern Eumenides Dorsum (9 deg - 11 deg N latitude, 159 deg - 162 deg longitude) as a potential Mars Pathfinder landing site

NASA Technical Reports Server (NTRS)

Parker, Tim J.

1994-01-01

The proposed site is the northernmost occurrence of the Medusae Fossae Formation (MFF), and lies at or below the -2 km contour. The MFF is the famous radar 'stealth' deposit that extends from south of Olympus Mons westward across southern Amazonis Planitia to southern Elysium Planitia. The MFF appears to be composed of some kind of wind-eroded friable material, the origin of which is very problematic. It appears to be a radar-absorbing material, whereas Mars' south polar layered deposits appear bright in the same scenes. Synthetic aperture radar images of young terrestrial ash deposits in the Andes also appear relatively bright. The MFF's radar signature appears to require a uniformly fine-grained material (on the order of dust-sized to fine sand-sized) at least several meters thick, in order not to transmit reflections off underlying terrain or internal reflective horizons. The proposed Pathfinder landing site lies on a relatively smooth, 'unmodified' portion of the MFF, more than 100 km away from its northern and western edges, which exhibit evidence of eolian etching in the form of closely spaced yardings. There are no large craters or steep slopes within a few hundred kilometers of the landing site.

Honeycomb-Textured Landforms in Northwestern Hellas Planitia

NASA Image and Video Library

2017-11-28

This image from NASA's Mars Reconnaissance Orbiter (MRO) targets a portion of a group of honeycomb-textured landforms in northwestern Hellas Planitia, which is part of one of the largest and most ancient impact basins on Mars. In a larger Context Camera image, the individual "cells" are about 5 to 10 kilometers wide. With HiRISE, we see much greater detail of these cells, like sand ripples that indicate wind erosion has played some role here. We also see distinctive exposures of bedrock that cut across the floor and wall of the cells. These resemble dykes, which are usually formed by volcanic activity. Additionally, the lack of impact craters suggests that the landscape, along with these features, have been recently reshaped by a process, or number of processes that may even be active today. Scientists have been debating how these honeycombed features are created, theorizing from glacial events, lake formation, volcanic activity, and tectonic activity, to wind erosion. The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. [The original image scale is 53.8 centimeters (21.2 inches) per pixel (with 2 x 2 binning); objects on the order of 161 centimeters (23.5 inches) across are resolved.] North is up. https://photojournal.jpl.nasa.gov/catalog/PIA22118

Western Arcadia Planitia

NASA Image and Video Library

2003-03-13

This is a Mars Odyssey visible color image of an unnamed crater in western Arcadia Planitia (near 39 degrees N, 179 degrees E). The crater shows a number of interesting internal and external features that suggest that it has undergone substantial modification since it formed. These features include concentric layers and radial streaks of brighter, redder materials inside the crater, and a heavily degraded rim and ejecta blanket. The patterns inside the crater suggest that material has flowed or slumped towards the center. Other craters with features like this have been seen at both northern and southern mid latitudes The distribution of these kinds of craters suggests the possible influence of surface or subsurface ice in the formation of these enigmatic features. The image was taken on September 29, 2002 during late northern spring. This is an approximate true color image, generated from a long strip of visible red (654 nm), green (540 nm), and blue (425 nm) filter images that were calibrated using a combination of pre-flight measurements and Hubble images of Mars. The colors appear perhaps a bit darker than one might expect; this is most likely because the images were acquired in late afternoon (roughly 4:40 p.m. local solar time) and the low Sun angle results in an overall darker surface. http://photojournal.jpl.nasa.gov/catalog/PIA04263

Amazonis Planitia

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site] (Released 5 July 2002) This is an image of a crater within part of Amazonis Planitia, located at 22.9N, 152.5W. This image features a number of common features exhibited by Martian craters. The crater is sufficiently large to exhibit a central peak that is seen in the upper right hand corner if the image. Also apparent is the slump blocks on the inside of the crater walls. When the crater was first formed, the crater walls were unstable and subsequently formed a series of landslides over time that formed the hummocky terrain just inside the present crater wall. While these cratering features are common to craters formed on other planetary bodies, such as the moon, the ejecta blanket surrounding the crater displays a morphology that is more unique to Mars. The lobate morphology implies that the ejecta blanket was emplaced in an almost fluid fashion rather than the traditional ballistic ejecta emplacement. This crater morphology occurs on Mars where water ice is suspected to be present just beneath the surface. The impact that created the crater would have enough energy to melt large amounts of water that could form the mud or debris flows that characterize the ejecta morphology that is seen in this image.

Pedestal Craters in Utopia Planitia and Malea Planum: Evidence for a Past Ice-Rich Substrate from Marginal Sublimation Pits.

NASA Astrophysics Data System (ADS)

Kadish, S. J.; Head, J. W.; Barlow, N. G.; Marchant, D. R.

2008-09-01

Introduction: Pedestal craters (Pd) are a subclass of impact craters unique to Mars [1] characterized by a crater perched near the center of a pedestal (mesa or plateau) that is surrounded by a quasi-circular, outward-facing scarp. The marginal scarp is usually several crater diameters from the crater rim (Figs. 2,4,5), and tens to over 100 meters above the surrounding plains (Fig. 2). Pd have been interpreted to form by armoring of the proximal substrate during the impact event. Hypotheses for the armoring mechanism include an ejecta covering [e.g., 3], increased ejecta mobilization caused by volatile substrates [4], distal glassy/melt-rich veneers [5], and/or an atmospheric blast/thermal effect [6]. Subsequently, a marginal scarp forms by preferential erosion of the substrate surrounding the armored region, most commonly thought to involve eolian removal of fine-grained, non-armored material [e.g., 3]. An understanding of the distribution of Pd, which form predominantly poleward of ~40°N and S latitude [7-9] (Fig. 1), and the role of redistribution of ice and dust during periods of climate change [e.g., 10-11], suggests that the substrate might have been volatile-rich [8-9, 12-14]. As such, some researchers [e.g., 8-9] have proposed a model for Pd formation that involves impact during periods of higher obliquity, when mid- to high-latitude substrates were characterized by thick deposits of snow and ice [e.g., 15]. Subsequent sublimation of the volatile units, except below the armored regions, yielded the perched Pd. Thus, this model predicts that thick deposits of snow/ice should underlie Pd. This is in contrast to the eolian model [3], which calls primarily for deflation of sand and dust. Here, we show the results of our study [8,16] that has documented and characterized 2461 Pd on Mars equatorward of ~65° N and S latitude (Fig. 1) in order to test these hypotheses for the origin of pedestal craters. In particular, we report on the detection of 50 Pd in Utopia Planitia and 21 Pd in Malea Planum that have pits in their marginal scarps [17]. We interpret these as sublimation pits (Fig. 3), providing evidence for snow/ice deposits preserved below the protective cover of the Pd. Marginal Pits in Pedestal Craters: Pedestal craters with marginal pits are a newly identified crater morphology in which one or more pits exist along the marginal scarp of a Pd (Figs. 2,4,5). The ejecta deposit surface (top of the pedestal) is perched ~100 m above the surrounding terrain (Fig. 2), about twice as high as a typical Pd crater. At the Pd plateau edge, the marginal scarp slopes down to the surrounding terrain, except where it is interrupted by a pit. The pits have a typical depth of ~20 m, often contain isolated mesas (Fig. 2), and are elongated, generally spanning <3 km in length (measured tangential to the pedestal margin) and <1 km in width (measured normal to the pedestal margin). In some cases, pits appear to coalesce to form larger pits (Fig. 5), and can yield a marginal, moatlike depression along a significant part of the pedestal circumference. Altimetry data from MOLA indicate that pits form in the side of the pedestal scarp; they do not extend below the elevation of the surrounding substrate (profiles in Fig. 2). Pd containing scarp pits identified thus far occur poleward of 48°N in Utopia Planitia and 58°S in Malea Planum (orange dots in Fig. 1). Pits are similar in morphology to dissected terrain [11,18] and pits on the floors of some ancient outflow channels [19], both thought to represent sublimation of an ice-rich substrate. They are also similar to formerly ice-rich and now beheaded pits in the proximal part of debris-covered glaciers on Earth [20] and Mars [21] (see also [22]). Both of the regions in which we observe Pd with marginal pits also exhibit scallop-shaped depressions, indicative of sublimation of interstitial ice [e.g. 23-25]. Climate models show that these specific regions are both predicted to have high seasonal water-ice accumulations during periods of high obliquity [26,27]. Discussion: The morphologic similarity between the marginal pits associated with Pd and ice sublimation pits leads us to favor an origin of preferential sublimation of ice/snow from the Pd scarp. In this interpretation, an impact crater forms in a thick (~10s to ~100s m) regional highlatitude deposit of ice and snow, mixed with dust. The area around the crater (the future pedestal surface) is armored by proximal ejecta and distal sintering effects of impact melt and atmospheric blast/thermal effects accompanying crater formation [5-6]. Following crater formation, obliquitydriven climate change leads to removal of the intervening snow and ice, leaving the Pd perched. Over time, the volatile-rich scarp margins, where the armoring tapers off, undergo continued sublimation to produce the pits, while the heavily armored Pd surface inhibits/prevents sublimation of underlying volatiles (Fig. 3). Ice-rich layered substrates are thus interpreted to be preserved under Pd. On the basis of our analysis, Pd represent the remnants of a past extensive, layered, climate-related deposit, similar to, but thicker than the latitude-dependent mantle emplaced in a recent ice age [11,18]. Due to the large number and widespread distribution of Pd (Fig. 1) [8,9,16], we believe that this climate-related deposit persisted for a considerable part of the recent past, implying that obliquity was relatively higher than at present during a significant portion of the Amazonian period of the history of Mars. References: [1] Barlow, N. et al. (2000) JGR, 105, 26733. [2] McCauley, J. (1973) JGR, 78, 4123. [3] Arvidson, R. (1976) Icarus, 27, 503. [4] Osinski, G. (2006) MAPS, 41, 1571. [5] Schultz, P. and Mustard, J. (2004) JGR, 109, E01001. [6] Wrobel, K. et al. (2006) MAPS, 41, 1539. [7] Mouginis-Mark, P. (1979) JGR, 84, 8011. [8] Kadish, S. and Barlow, N. (2006) LPSC 37, #1254. [9] Kadish, S. et al. (2008) LPSC 39, #1766. [10] Jakosky, B. et al. (1995) JGR, 100, 1579. [11] Head, J. et al. (2003) Nature, 426, 797. [12] Barlow, N. (2005) RVAMIC, #3041. [13] Head, J. and Roth, R. (1976) LSI, 50-52. [14] Schultz, P. and Lutz, A. (1988) Icarus, 73, 91. [15] Levrard, B. et al. (2004) Nature, 431, 1072. [16] Kadish, S. et al. (2008) JGR, in progress. [17] Kadish, S. et al. (2008) GRL, in progress. [18] Mustard, J. et al. (2001) Nature, 412, 411. [19] Levy, J. and Head, J. (2005) Terra Nova, 17, 503. [20] Marchant, D. and Head, J. (2007) Icarus, 192, 187. [21] Head, J. and Marchant, D. (2008) Workshop on Martian Gullies, #8009. [22] Moore, J. et al. (1996) Icarus, 122, 63. [23] Lefort, A. et al. (2006) 4th Mars Polar Science Conf., #8061. [24] Zanetti, M. et al. (2008) LPSC 39, 1682. [25] Morgenstern, A. et al. (2007) JGR, 112, E06010. [26] Forget, F. et al. (2006) Science, 311, 368-371. [27] Madeleine, B. et al. (2007) LPSC 38, #1778.

The Enhancement of Water Ice Content in the Local Area Northeast of Arcadia Planitia: Evidence from Neutron Data from HEND (Mars Odyssey) and Elevation from MOLA (MGS)

NASA Technical Reports Server (NTRS)

Sanin, A. B.; Mitrofanov, I. G.; Kozyrev, A. S.; Litvak, M. L.; Tretyakov, V.; Smith, D. E.; Zuber, M. T.; Boynton, W.; Saunders, R. S.

2003-01-01

The first year of neutron mapping measurements from the Mars Odyssey spacecraft revealed enormous hydrogen-rich regions in the southern and northern hemispheres of the Martian crust that imply significant amounts of near surface water ice. The hydrogen-rich areas of the southern and northern regions appear generally comparable in spatial extent and water ice content. This observation is interesting in light of topography measured by the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor (MGS) spacecraft, which shows a significant difference in elevation between northern lowlands and southern highlands that could imply a difference in seasonal CO2 condensation. In this study we correlate the high energy neutron flux observed by HEND (Mars Odyssey) and surface elevation measured by MOLA in order to interpret the seasonal change in epithermal neutron flux in terms near-surface water ice content.

Formation and disruption of aquifers in southwestern Chryse Planitia, Mars

USGS Publications Warehouse

Rodriguez, J.A.P.; Tanaka, K.L.; Kargel, J.S.; Dohm, J.M.; Kuzmin, R.; Fairen, A.G.; Sasaki, S.; Komatsu, G.; Schulze-Makuch, D.; Jianguo, Y.

2007-01-01

We present geologic evidence suggesting that after the development of Mars' cryolithosphere, the formation of aquifers in southwestern Chryse Planitia and their subsequent disruption led to extensive regional resurfacing during the Late Hesperian, and perhaps even during the Amazonian. In our model, these aquifers formed preferentially along thrust faults associated with wrinkle ridges, as well as along fault systems peripheral to impact craters. The characteristics of degraded wrinkle ridges and impact craters in southwestern Chryse Planitia indicate a profound role of subsurface volatiles and especially liquid water in the upper crust (the upper one hundred to a few thousands of meters). Like lunar wrinkle ridges, the martian ones are presumed to mark the surface extensions of thrust faults, but in our study area the wrinkle ridges are heavily modified. Wrinkle ridges and nearby plains have locally undergone collapse, and in other areas they are associated with domical intrusions we interpret as mud volcanoes and mud diapirs. In at least one instance, a sinuous valley emanates from a modified wrinkle ridge, further indicating hydrological influences on these thrust-fault-controlled features. A key must be the formation of volatile-rich crust. Primary crustal formation and differentiation incorporated juvenile volatiles into the global crust, but the crustal record here was then strongly modified by the giant Chryse impact. The decipherable rock record here begins with the Chryse impact and continues with the resulting basin's erosion and infilling, which includes outflow channel activity. We propose that in Simud Vallis surface flow dissection into the base of the cryolithosphere-produced zones where water infiltrated and migrated along SW-dipping strata deformed by the Chryse impact, thereby forming an extensive aquifer in southwestern Chryse Planitia. In this region, compressive stresses produced by the rise of Tharsis led to the formation of wrinkle ridges. Zones of high fracture density within the highly strained planes of the thrust faults underlying the wrinkle ridges formed regions of high permeability; thus, groundwater likely flowed and gathered along these tectonic structures to form zones of elevated permeability. Volatile depletion and migration within the upper crustal materials, predominantly along fault systems, led to structurally controlled episodic resurfacing in southwestern Chryse Planitia. The erosional modification of impact craters in this region is linked to these processes. This erosion is scale independent over a range of crater diameters from a few hundred meters to tens of kilometers. According to our model, pressurized water and sediment intruded and locally extruded and caused crustal subsidence and other degradational activity across this region. The modification of craters across this wide range of sizes, according to our model, implies that there was intensive mobilization of liquid water in the upper crust ranging from about one hundred to several thousand meters deep. ?? 2007 Elsevier Inc. All rights reserved.

Geologic map of Tooting crater, Amazonis Planitia region of Mars

USGS Publications Warehouse

Mouginis-Mark, Peter J.

2015-01-01

Tooting crater has a diameter of 27.2 km, and formed on virtually flat lava flows within Amazonis Planitia ~1,300 km west of the summit of Olympus Mons volcano, where there appear to have been no other major topographic features prior to the impact. The crater formed in an area ~185 x 135 km that is at an elevation between −3,870 m and −3,874 m relative to the Mars Orbiter Laser Altimeter (MOLA) Mars datum. This fortuitous situation (for example, a bland, horizontal target) allows the geometry of the crater and the thickness of the ejecta blanket to be accurately determined by subtracting the appropriate elevation of the surrounding landscape (−3,872 m) from the individual MOLA measurements across the crater. Thus, for the first time, it is possible to determine the radial decrease of ejecta thickness as a function of distance away from the rim crest. On the basis of the four discrete ejecta layers surrounding the crater cavity, Tooting crater is classified as a Multiple-Layered Ejecta (MLE) crater. By virtue of the asymmetric distribution of secondary craters and the greater thickness of ejecta to the northeast, Morris and others (2010) proposed that Tooting crater formed by an oblique impact from the southwest. The maximum range of blocks that produced identifiable secondary craters is ~500 km (~36.0 crater radii) from the northeast rim crest. In contrast, secondary craters are only identifiable ~215 km (15.8 radii) to the southeast and 225 km (16.5 radii) to the west.

Mars Atmospheric Temperature and Dust Storm Tracking

NASA Image and Video Library

2016-06-09

This graphic overlays Martian atmospheric temperature data as curtains over an image of Mars taken during a regional dust storm. The temperature profiles extend from the surface to about 50 miles (80 kilometers) up. Temperatures are color coded, ranging from minus 243 degrees Fahrenheit (minus 153 degrees Celsius) where coded purple to minus 9 F (minus 23 C) where coded red. The temperature data and global image were both recorded on Oct. 18, 2014, by instruments on NASA's Mars Reconnaissance Orbiter: Mars Climate Sounder and Mars Color Imager. On that day a regional dust storm was active in the Acidalia Planitia region of northern Mars, at the upper center of this image. A storm from this area in typically travels south and grows into a large regional storm in the southern hemisphere during southern spring. That type of southern-spring storm and two other large regional dust storms repeat as a three-storm series most Martian years. The pattern has been identified from their effects on atmospheric temperature in a layer about 16 miles (25 kilometers) above the surface. http://photojournal.jpl.nasa.gov/catalog/PIA20747

Bright Summer Afternoon on the Mars Utopian Planitia

NASA Technical Reports Server (NTRS)

1976-01-01

A UTOPIAN BRIGHT SUMMER AFTERNOON ON MARS--Looking south from Viking 2 on September 6, the orange-red surface of the nearly level plain upon which the spacecraft sits is seen strewn with rocks as large as three feet across. Many of these rocks are porous and sponge-like, similar to some of Earth's volcanic rocks. Other rocks are coarse-grained such as the large rock at lower left. Between the rocks, the surface is blanketed with fine-grained material that, in places, is piled into small drifts and banked against some of the larger blocks. The cylindrical mast with the orange cable is the low-gain antenna used to receive commands from Earth.

Mars gravity: high-resolution results from viking orbiter 2.

PubMed

Sjogren, W L

1979-03-09

Doppler radio-tracking data have provided detailed measurements for a martian gravity map extending from 30 degrees S to 65 degrees N in latitude and through 360 degrees of longitude. The feature resolution is approximately 500 kilometers, revealing a huge anomaly associated with Olympus Mons, a mascon in Isidis Planitia, and other anomalies correlated with volcanic structure. Olympus Mons has been modeled with a 600-kilometer surface disk having a mass of 8.7 x 1021grams.

Evidence of volcanic and glacial activity in Chryse and Acidalia Planitiae, Mars

USGS Publications Warehouse

Martinez-Alonso, Sara; Mellon, Michael T.; Banks, Maria E.; Keszthelyi, Laszlo P.; McEwen, Alfred S.

2011-01-01

Chryse and Acidalia Planitiae show numerous examples of enigmatic landforms previously interpreted to have been influenced by a water/ice-rich geologic history. These landforms include giant polygons bounded by kilometer-scale arcuate troughs, bright pitted mounds, and mesa-like features. To investigate the significance of the last we have analyzed in detail the region between 60°N, 290°E and 10°N, 360°E utilizing HiRISE (High Resolution Imaging Science Experiment) images as well as regional-scale data for context. The mesas may be analogous to terrestrial tuyas (emergent sub-ice volcanoes), although definitive proof has not been identified. We also report on a blocky unit and associated landforms (drumlins, eskers, inverted valleys, kettle holes) consistent with ice-emplaced volcanic or volcano-sedimentary flows. The spatial association between tuya-like mesas, ice-emplaced flows, and further possible evidence of volcanism (deflated flow fronts, volcanic vents, columnar jointing, rootless cones), and an extensive fluid-rich substratum (giant polygons, bright mounds, rampart craters), allows for the possibility of glaciovolcanic activity in the region.Landforms indicative of glacial activity on Chryse/Acidalia suggest a paleoclimatic environment remarkably different from today's. Climate changes on Mars (driven by orbital/obliquity changes) or giant outflow channel activity could have resulted in ice-sheet-related landforms far from the current polar caps.

Acidalia Planitia

NASA Technical Reports Server (NTRS)

2003-01-01

[figure removed for brevity, see original site]

The small mounds with summit depressions in the northern portion of this image have an unknown origin. Some scientists think they may be cinder cones, while others think they may be pseudocraters, formed by the interaction of lava and ice. These features are also observed in other areas of Mars' northern plains, such as Isidis Planitia.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image information: VIS instrument. Latitude XX, Longitude XX East (XX West). 19 meter/pixel resolution.

Giant polygons and mounds in the lowlands of Mars: signatures of an ancient ocean?

PubMed

Oehler, Dorothy Z; Allen, Carlton C

2012-06-01

This paper presents the hypothesis that the well-known giant polygons and bright mounds of the martian lowlands may be related to a common process-a process of fluid expulsion that results from burial of fine-grained sediments beneath a body of water. Specifically, we hypothesize that giant polygons and mounds in Chryse and Acidalia Planitiae are analogous to kilometer-scale polygons and mud volcanoes in terrestrial, marine basins and that the co-occurrence of masses of these features in Chryse and Acidalia may be the signature of sedimentary processes in an ancient martian ocean. We base this hypothesis on recent data from both Earth and Mars. On Earth, 3-D seismic data illustrate kilometer-scale polygons that may be analogous to the giant polygons on Mars. The terrestrial polygons form in fine-grained sediments that have been deposited and buried in passive-margin, marine settings. These polygons are thought to result from compaction/dewatering, and they are commonly associated with fluid expulsion features, such as mud volcanoes. On Mars, in Chryse and Acidalia Planitiae, orbital data demonstrate that giant polygons and mounds have overlapping spatial distributions. There, each set of features occurs within a geological setting that is seemingly analogous to that of the terrestrial, kilometer-scale polygons (broad basin of deposition, predicted fine-grained sediments, and lack of significant horizontal stress). Regionally, the martian polygons and mounds both show a correlation to elevation, as if their formation were related to past water levels. Although these observations are based on older data with incomplete coverage, a similar correlation to elevation has been established in one local area studied in detail with newer higher-resolution data. Further mapping with the latest data sets should more clearly elucidate the relationship(s) of the polygons and mounds to elevation over the entire Chryse-Acidalia region and thereby provide more insight into this hypothesis.

Geomorphological Evidence for Shallow Ice in the Southern Hemisphere of Mars

NASA Astrophysics Data System (ADS)

Viola, D.; McEwen, A. S.

2018-01-01

The localized loss of near-surface excess ice on Mars by sublimation (and perhaps melting) can produce thermokarstic collapse features such as expanded craters and scalloped depressions, which can be indicators of the preservation of shallow ice. We demonstrate this by identifying High Resolution Imaging Science Experiment images containing expanded craters south of Arcadia Planitia (25-40°N) and observe a spatial correlation between regions with thermokarst and the lowest-latitude ice-exposing impact craters identified to date. In addition to widespread thermokarst north of 35°N, we observe localized thermokarst features that we interpret as patchy ice as far south as 25°N. Few ice-exposing craters have been identified in the southern hemisphere of Mars since they are easier to find in dusty, high-albedo regions, but the relationship among expanded craters, ice-exposing impacts, and the predicted ice table boundary in Arcadia Planitia allows us to extend this thermokarst survey into the southern midlatitudes (30-60°S) to infer the presence of ice today. Our observations suggest that the southern hemisphere excess ice boundary lies at 45°S regionally. At lower latitudes, some isolated terrains (e.g., crater fill and pole-facing slopes) also contain thermokarst, suggesting local ice preservation. We look for spatial relationships between our results and surface properties (e.g., slope and neutron spectrometer water ice concentration) and ice table models to understand the observed ice distribution. Our results show trends with thermal inertia and dust cover and are broadly consistent with ice deposition during a period with a higher relative humidity than today. Shallow, lower-latitude ice deposits are of interest for future exploration.

Possible Tuff Cones In Isidis Planitia, Mars

NASA Astrophysics Data System (ADS)

Seabrook, A. M.; Rothery, D. A.; Bridges, J. C.; Wright, I. P.

The Beagle 2 lander of the ESA Mars Express mission will touch down on the martian surface in December 2003 to conduct a primarily exobiological mission. The landing site will be within Isidis Planitia, an 1100 km diameter impact basin. Isidis contains many sub-kilometre-sized cones. These can be found singly, in clusters, and in straight or arcuate chains extending many kilometres. In some areas of the basin these cones can occupy over 10% of the surface, with the most densely populated areas being in the older western half of the basin. There are few cones around the basin rim. There is also variation in the erosional state of the cones both across the basin, and within smaller areas, implying a range in time of formation for the cones. We currently favour a tuff cone origin as an explanation for these features. Tuff cones on Earth are rooted volcanic features formed at vents by the interaction between magma or magmatic heat and surface or near-surface water. Lava flows likely to be associated with at least some of the cones if they had a cinder cone (rooted eruptions at vents in a dry environment) origin are absent. This suggests the involvement of suffi- cient volatiles both to explosively fragment the erupting magma, and to cool the ejecta enough to prevent the formation of clastogenic flows. If our tuff cone interpretation is correct, this has implications for the presence, abundance and long-term persistence of sub-surface volatiles (water or carbon dioxide) on Mars. An understanding of the mechanism of formation of the Isidis cones will assist the characterisation of the basin in preparation for the landing of Beagle 2, by providing information about the history of volatiles and volcanism in the basin, and the processes that resulted in the surface we see today.

Goldstone/VLA 3.5cm Mars Radar Observations - "Stealths" and South Polar Regions

NASA Astrophysics Data System (ADS)

Butler, Bryan; Chizek, M. R.; Slade, M. A.; Haldemann, A. F.; Muhleman, D. O.; Mao, T. F.

2006-09-01

The opposition of Mars in 2003 provided a fantastic opportunity to use the combined Goldstone/VLA radar to probe the surface with the highest resolution ever obtained on Mars with that instrument (as good as 70 km). Observations were made on August 11, 19, 28, and September 8. Details of data reduction and analysis of the radar echoes from the volcanic regions of the planet are presented in a companion paper in these proceedings (Chizek et al.). We will present results related to "Stealth" (and other radar-dark regions of the planet, including the Argyre and Hellas Planitiae, and a region to the west of the Elysium Mons caldera), and the south polar residual and seasonal ice caps. The size, shape, and reflectivity characteristics of Stealth and "mega-Stealth" (Edgett et al. 1997) are reaffirmed, with a better viewing geometry of the western extent of the feature than had been obtained previously. It had been speculated previously that Hellas Planitia should also be radar dark - this is confirmed by our imaging, though the reflectivity is not as low as for Stealth. We find a new radar dark area to the west of Elysium Mons, which is likely an ash fall from that volcano (similar to the relationship between Stealth and the Tharsis volcanoes). The south polar residual ice cap is a very bright reflector, as seen previously, but we now also see a very bright reflection from the seasonal cap, not seen previously. The cap is not uniformly bright, however, and the extent of the bright reflection does not correspond to that expected from the retreat of the cap as measured either from albedo or thermal emission characteristics. The NRAO is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Marte Vallis Platy Flows

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-442, 4 August 2003

The Marte Vallis system, located east of Cerberus and west of Amazonis Planitia, is known for its array of broken, platy flow features. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a close-up view of some of these plates; they appear to be like puzzle pieces that have been broken apart and moved away from each other. The Mars science community has been discussing these features for the past several years--either the flows in Marte Vallis are lava flows, or mud flows. In either case, the material was very fluid and had a thin crust on its surface. As the material continued to flow through the valley system, the crust broke up into smaller plates that were then rafted some distance down the valley. This picture is located near 6.9oN, 182.8oW. It is illuminated by sunlight from the left.

Possible Rootless Cones or Pseudo craters on Mars

NASA Technical Reports Server (NTRS)

1999-01-01

High-resolution images from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) have revealed small cone-shaped structures on lava flows in southern Elysium Planitia, Marte Valles, and northwestern Amazonis Planitia in the northern hemisphere of the red planet. The most likely interpretation of these cones is that they may be volcanic features known as 'pseudo craters' or 'rootless cones.' They share several key characteristics with pseudo craters on Earth: they are distributed in small clusters independent of structural patterns, are superimposed on fresh lava flows, and they do not appear to have erupted lavas themselves. The white box in the picture above left shows the location of one of the MOC images of possible pseudocraters on Mars. The white box is drawn upon a MOC red wide angle context image acquired at the same time as the high resolution view, shown on the right above. Located in northwestern Amazonis Planitia near 24.8oN, 171.3oW, both the context image and high-resolution view are illuminated from the lower left. The high resolution view shows several possible pseudocraters (cone-shaped features with holes or pits at their summits) that occur on top of a rough-textured lava plain. The context frame covers an area 115 km (71 mi) across, the high-resolution view is 3 km (1.9 mi) across. Pseudocraters form by explosions due to the interaction of molten lava with a water-rich surface. Possible martian pseudocraters are of interest because they may mark the locations of shallow water or ice at the time the lava was emplaced. Viking Orbiter images have shown structures in other regions of Mars that were interpreted to be pseudocraters, but the interpretations were uncertain because the morphology was poorly resolved, it was unclear if they occurred on volcanic surfaces, and they have diameters as much as a factor of 3 larger than terrestrial pseudocraters. The cone-shaped morphology is well resolved in the cones imaged by MOC, and they have basal diameters of less than 250 m (273 yards), consistent with terrestrial examples. The cones rest on a surface with a distinctive morphology consisting of ridged plates that have rafted apart, which MOC team members have interpreted as the surface of voluminous lava flows. The surface shown here (above right) looks relatively fresh and has very few impact craters on it, which suggests that the lava flows and the cones are both geologically young. However, MOC images in other areas reveal such apparently young surfaces being exhumed (presumably by wind erosion) from beneath a blanket of overlying material. Impact processes may harden the blanket, or cover it with materials that cannot be removed by wind, so the wind erosion leaves behind elevated 'pedestalcraters.' The cones shown here are not typical of pedestal craters, but it is important to consider this alternative interpretation. MGS MOC first began taking pictures of Mars in mid-September 1997. The planet that has been revealed by this camera is often strange, new, and exciting. The possibility that lava and water or ice have interacted to create features like pseudocraters indicates that Mars has had a diverse and complex past that researchers are only just beginning to understand.

Fluid Expulsion, Habitability, and the Search for Life on Mars

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Allen, Carlton C.

2012-01-01

Habitability assessments are critical for identifying settings in which potential biosignatures could exist in quantities large enough to be detected by rovers. Habitability depends on 1) the potential for long-lived liquid water, 2) conditions affording protection from surface processes destructive to organic biomolecules, and 3) a source of renewing nutrients and energy. Of these criteria, the latter is often overlooked. Here we present an analysis of a large "ghost" crater in northern Chryse Planitia [1] that appears to have satisfied each of these requirements, with several processes providing potential sources of nutrient/energy renewal [1-2]. This analysis can serve as a model for identifying other localities that could provide similarly favorable settings in which to seek evidence of life on Mars.

The surface of Mars: there view from the viking 1 lander.

PubMed

Mutch, T A; Binder, A B; Huck, F O; Levinthal, E C; Liebes, S; Morris, E C; Patterson, W R; Pollack, J B; Sagan, C; Taylor, G R

1976-08-27

The first photographs ever returned from the surface of Mars were obtained by two facsimile cameras aboard the Viking 1 lander, including black-and-white and color, 0.12 degrees and 0.04 degrees resolution, and monoscopic and stereoscopic images. The surface, on the western slopes of Chtyse Planitia, is a boulder-strewn deeply reddish desert, with distant eminences-some of which may be the rims of impact craters-surmounted by a pink sky. Both impact and aeolian processes are evident. After dissipation of a small dust cloud stirred by the landing maneuvers, no subsequent signs of movement were detected on the landscape, and nothing has been observed that is indicative of macroscopic biology at this time and place.

New radar-derived topography for the northern hemisphere of Mars

NASA Technical Reports Server (NTRS)

Downs, G. S.; Thompson, T. W.; Mouginis-Mark, P. J.; Zisk, S. H.

1982-01-01

Earth-based radar altimetry data for the northern equatorial belt of Mars (6 deg S-23 deg N) have recently been reduced to a common basis corresponding to the 6.1-mbar reference surface. A first look at these data indicates that the elevations of Tharsis, Elysium, and Lunae Planum are lower (by 2-5 km) than has been suggested by previous estimates. These differences show that the required amount of tectonic uplift (or constructional volcanism) for each area is less than has been previously envisioned. Atmospheric or surficial conditions are suggested which may explain the discrepancies between the radar topography and elevations measured by other techniques. The topographies of Chryse Planitia, Syrtis Major, and Valles Marineris are also described.

The surface of Mars: The view from the Viking 1 lander

USGS Publications Warehouse

Mutch, T.A.; Binder, A.B.; Huck, F.O.; Levinthal, E.C.; Liebes, S.; Morris, E.C.; Patterson, W.R.; Pollack, James B.; Sagan, C.; Taylor, G.R.

1976-01-01

The first photographs ever returned from the surface of Mars were obtained by two facsimile cameras aboard the Viking 1 lander, including black-and-white and color, 0.12?? and 0.04?? resolution, and monoscopic and stereoscopic images. The surface, on the western slopes of Chryse Planitia, is a boulder-strewn deeply reddish desert, with distant eminences - some of which may be the rims of impact craters - surmounted by a pink sky. Both impact and aeolian processes are evident. After dissipation of a small dust cloud stirred by the landing maneuvers, no subsequent signs of movement were detected on the landscape, and nothing has been observed that is indicative of macroscopic biology at this time and place.

Origins of Sinuous and Braided Channels on Ascraeus Mons, Mars - A Keck Geology Consortium Undergraduate Research Project

NASA Technical Reports Server (NTRS)

de Wet, A. P.; Bleacher, J. E.; Garry, W. B.

2012-01-01

Water has clearly played an important part in the geological evolution of Mars. There are many features on Mars that were almost certainly formed by fluvial processes -- for example, the channels Kasei Valles and Ares Vallis in the Chryse Planitia area of Mars are almost certainly fluvial features. On the other hand, there are many channel features that are much more difficult to interpret -- and have been variously attributed to volcanic and fluvial processes. Clearly unraveling the details of the role of water on Mars is extremely important, especially in the context of the search of extinct or extant life. In this project we built on our recent work in determining the origin of one channel on the southwest rift apron of Ascraeus Mons. This project, funded by the Keck Geology Consortium and involving 4 undergraduate geology majors took advantage of the recently available datasets to map and analyze similar features on Ascraeus Mons and some other areas of Mars. A clearer understanding of how these particular channel features formed might lead to the development of better criteria to distinguish how other Martian channel features formed. Ultimately this might provide us with a better understanding of the role of volcanic and fluvial processes in the geological evolution of Mars.

Paleolakes on Mars

NASA Technical Reports Server (NTRS)

Wharton, R. A. Jr; Crosby, J. M.; McKay, C. P.; Rice, J. W. Jr; Wharton RA, ,. J. r. (Principal Investigator)

1995-01-01

Observational evidence such as outflow channels and valley networks suggest that in the past there was flowing water on Mars. The images of fluvial features on Mars logically suggest that there must exist downstream locations in which the water pooled and the sediment load deposited (i.e. lakes). Sediments and morphological features associated with the martian paleolakes are believed to occur in Valles Marineris, and several large basins including Amazonis, Chryse and Elysium planitia. As Mars became progressively colder over geological time, any lakes on its surface would have become seasonally, and eventually perennially ice-covered. We know from polar lakes on Earth that ice-covered lakes can persist even when the mean annual temperature falls below freezing. Thus, the most recent lacustrine sediments on Mars were probably deposited in ice-covered lakes. While life outside of the Earth's atmosphere has yet to be observed, there is a general consensus among exobiologists that the search for extraterrestrial life should be based upon liquid water. The inference that there was liquid water on Mars during an earlier epoch is the primary motivation for considering the possibility of life during this time. It would be of enormous interest from both an exobiological and paleolimnological perspective to discover lakes or the evidence of former lakes on another planet such as Mars. Limnology would then become an interplanetary science.

Paleolakes on Mars.

PubMed

Wharton, R A; Crosby, J M; McKay, C P; Rice, J W

1995-01-01

Observational evidence such as outflow channels and valley networks suggest that in the past there was flowing water on Mars. The images of fluvial features on Mars logically suggest that there must exist downstream locations in which the water pooled and the sediment load deposited (i.e. lakes). Sediments and morphological features associated with the martian paleolakes are believed to occur in Valles Marineris, and several large basins including Amazonis, Chryse and Elysium planitia. As Mars became progressively colder over geological time, any lakes on its surface would have become seasonally, and eventually perennially ice-covered. We know from polar lakes on Earth that ice-covered lakes can persist even when the mean annual temperature falls below freezing. Thus, the most recent lacustrine sediments on Mars were probably deposited in ice-covered lakes. While life outside of the Earth's atmosphere has yet to be observed, there is a general consensus among exobiologists that the search for extraterrestrial life should be based upon liquid water. The inference that there was liquid water on Mars during an earlier epoch is the primary motivation for considering the possibility of life during this time. It would be of enormous interest from both an exobiological and paleolimnological perspective to discover lakes or the evidence of former lakes on another planet such as Mars. Limnology would then become an interplanetary science.

Looking for water related environments on Mars: analysis of reflectance spectra for present and future exploration

NASA Astrophysics Data System (ADS)

De Toffoli, B.; Carli, C.; Maturilli, A.; Sauro, F.; Massironi, M.; Helbert, J.

2017-09-01

Spectroscopic analyses of basalt epithermal alterations, clay minerals and samples representative of wet sedimentary environments in a broad wavelength range from the ultraviolet to the far-infrared provide new loads of information for present and future exploration of environments that could have been linked to water and gas emission. Specifically, methane emission centers on the Martian surface are high interest targets for Exo-Mars mission since they involve environments where life could have potentially arisen, grown and given a contribution to the degassing phenomenon. Such data will be applied to drive the analysis on remotely sensed hyperspectral images of Martian regions where surface expressions of water and sediments resurgences are recognisable, such as the mound fields detected in Utopia and Hellas basins and Vastitas Borealis.

Ancient geodynamics and global-scale hydrology on Mars.

PubMed

Phillips, R J; Zuber, M T; Solomon, S C; Golombek, M P; Jakosky, B M; Banerdt, W B; Smith, D E; Williams, R M; Hynek, B M; Aharonson, O; Hauck , S A

2001-03-30

Loading of the lithosphere of Mars by the Tharsis rise explains much of the global shape and long-wavelength gravity field of the planet, including a ring of negative gravity anomalies and a topographic trough around Tharsis, as well as gravity anomaly and topographic highs centered in Arabia Terra and extending northward toward Utopia. The Tharsis-induced trough and antipodal high were largely in place by the end of the Noachian Epoch and exerted control on the location and orientation of valley networks. The release of carbon dioxide and water accompanying the emplacement of approximately 3 x 10(8) cubic kilometers of Tharsis magmas may have sustained a warmer climate than at present, enabling the formation of ancient valley networks and fluvial landscape denudation in and adjacent to the large-scale trough.

The surface of Mars - The view from the Viking 1 lander

NASA Technical Reports Server (NTRS)

Mutch, T. A.; Patterson, W. R.; Binder, A. B.; Huck, F. O.; Taylor, G. R.; Levinthal, E. C.; Liebes, S., Jr.; Morris, E. C.; Pollack, J. B.; Sagan, C.

1976-01-01

Imagery of the surface of Mars obtained by Viking 1 is analyzed. The lander is situated on the western slopes of the 5-km deep Chryse Planitia depression, about 2 km higher than the floor. The topography is gently rolling. Angular rocks and small sand dunes are visible. There are very few craters; initial evaluations indicate that crater area densities are several orders of magnitude below saturation for crater sizes less than about 50 m. The presence of scour marks and of fine-grained deposits in some boulders indicates that some aeolian activity has occurred. Almost all the sky brightness can be attributed to scattering by particles present in the atmosphere. No signs of movement have been detected, consistent with the low seasonal winds recorded by meteorological instruments.

Dust devil track survey at Elysium Planitia, Mars: Implications for the InSight landing sites

NASA Astrophysics Data System (ADS)

Reiss, Dennis; Lorenz, Ralph D.

2016-03-01

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) robotic lander is scheduled to land in Elysium Planitia on Mars in September 2016. InSight will perform the first comprehensive surface-based geophysical investigation including seismic measurements. Knowledge about encounter rates of dust devils with the InSight lander are important for two main reasons: (1) dust devils will affect the scientific measurements, i.e., wind-induced seismic noise, and (2) the power-supply of the InSight lander and instruments is provided by solar arrays and previous landers and rovers on Mars were affected by a steady decline in electrical power output due to atmospheric dust deposition on the solar panels. Long term science operations were only made possible by dust clearing events of the solar arrays caused by wind gusts and dust devils. In this study we analyzed dust devil tracks (DDTs) at the final InSight landing site region in Elysium Planitia. Formation of DDTs is caused by the removal of a layer of dust by passing dust devils, hence in principle the same process as clearing of dust from solar panels. We mapped the number, size (width and length), and orientation of DDTs in repeat observations using High Resolution Imaging Science Experiment (HiRISE) images covering the exact same surface area acquired within a relatively short time span (<90 martian days). In total, we analyzed 557 newly formed dust devil tracks in 8 study areas. DDTs are morphologically relatively straight with a low mean sinuosity of 1.03 and only reach maximum widths of 30 m. The mean DDT width is 4 m, indicating that the dust devil size population is dominated by small dust devils with a diameter <10 m. The size-frequency distribution of DDTs follows a -2 power law. The mean lengths of DDTs are 0.62 km and 1.23 km for complete (tracks which are visible from their start to end point) and incomplete DDTs (tracks running across the HiRISE footprint), respectively. The alignment of DDTs in combination with Mars Climate Database (MCD) predicted wind directions imply that dust devils are moving from SE to NW until early northern autumn with a reversal to NW-SE directions of movement at LS = 200° consistent with the seasonal reversal in direction of the Hadley circulation. DDT formation rates vary between 0.002 and 0.08 ddt km-2 sol-1. DDT area formation rates using the measured DDT widths, lengths, and formation rates are in the range of 0.0003-0.00006 km2 km-2 sol-1, implying that a given spot on the surface may be cleared of dust only once between ∼3000 and 16,000 sols (i.e. every ∼5-24 Mars years). Measured DDT formation rates were used to find a scaling factor to the seasonal DDA index, and then integrated over the year to estimate a mean annual DDT formation rate of 0.046 ddt km-2 sol-1. This translates into a solar panel clearing recurrence interval estimate of ∼11 Mars years using the mean annual DDT formation rate, and the mean DDT width and length from all measured DDTs. Due to several uncertainties this solar panel clearing recurrence interval for the InSight landing should be seen as an upper limit estimate.

Ancient Origin of the U2 Small Nuclear RNA Gene-Targeting Non-LTR Retrotransposons Utopia

PubMed Central

Kojima, Kenji K.

2015-01-01

Most non-long terminal repeat (non-LTR) retrotransposons encoding a restriction-like endonuclease show target-specific integration into repetitive sequences such as ribosomal RNA genes and microsatellites. However, only a few target-specific lineages of non-LTR retrotransposons are distributed widely and no lineage is found across the eukaryotic kingdoms. Here we report the most widely distributed lineage of target sequence-specific non-LTR retrotransposons, designated Utopia. Utopia is found in three supergroups of eukaryotes: Amoebozoa, SAR, and Opisthokonta. Utopia is inserted into a specific site of U2 small nuclear RNA genes with different strength of specificity for each family. Utopia families from oomycetes and wasps show strong target specificity while only a small number of Utopia copies from reptiles are flanked with U2 snRNA genes. Oomycete Utopia families contain an “archaeal” RNase H domain upstream of reverse transcriptase (RT), which likely originated from a plant RNase H gene. Analysis of Utopia from oomycetes indicates that multiple lineages of Utopia have been maintained inside of U2 genes with few copy numbers. Phylogenetic analysis of RT suggests the monophyly of Utopia, and it likely dates back to the early evolution of eukaryotes. PMID:26556480

Lunar and Planetary Science XXXV: Mars Volcanology and Tectonics

NASA Technical Reports Server (NTRS)

2004-01-01

Reports from the session, "Mars Volcanology and Tectonics" include:Martian Shield Volcanoes; Estimating the Rheology of Basaltic Lava Flows; A Model for Variable Levee Formation Rates in an Active Lava Flow; Deflections in Lava Flow Directions Relative to Topography in the Tharsis Region: Indicators of Post-Flow Tectonic Motion; Fractal Variation with Changing Line Length: A Potential Problem for Planetary Lava Flow Identification; Burfellshraun:A Terrestrial Analogue to Recent Volcanism on Mars; Lava Domes of the Arcadia Region of Mars; Comparison of Plains Volcanism in the Tempe Terra Region of Mars to the Eastern Snake River Plains, Idaho with Implications for Geochemical Constraints; Vent Geology of Low-Shield Volcanoes from the Central Snake River Plain, Idaho: Lessons for Mars and the Moon; Field and Geochemical Study of Table Legs Butte and Quaking Aspen Butte, Eastern Snake River Plain, Idaho: An Analog to the Morphology of Small Shield Volcanoes on Mars; Variability in Morphology and Thermophysical Properties of Pitted Cones in Acidalia Planitia and Cydonia Mensae; A Volcano Composed of Light-colored Layered Deposits on the Floor of Valles Marineris; Analysis of Alba Patera Flows: A Comparison of Similarities and Differences Geomorphologic Studies of a Very Long Lava Flow in Tharsis, Mars; Radar Backscatter Characteristics of Basaltic Flow Fields: Results for Mauna Ulu, Kilauea Volcano, Hawaii;and Preliminary Lava Tube-fed Flow Abundance Mapping on Olympus Mons.

Geographic Distribution of QCDs Around the Northern Plains Basins of Mars and the Relationship to Lowland Materials

NASA Technical Reports Server (NTRS)

Buczkowski, D. L.; Frey, H. V.; McGill, G. E.

2005-01-01

It has been suggested that quasicircular depressions (QCDs) without a structural representation in Viking and MOC visible imagery represent buried impact craters [1,2,3,4]. Topographic depressions will form over impact craters buried by a differentially compacting cover material because total cover thickness, and thus total compaction, is greater over the center of completely buried impact craters than their rims [5]. If this is the process by which QCDs form, then only areas of differentially compacting materials should have QCDs. Previous work has established that there is a relationship of surface relief to diameter for QCDs around the Utopia Basin [6]. The slope of the trend of this relationship varies depending on cover thickness, becoming steeper with decreasing thickness [7]. Comparing trendslopes of QCDs around different lowland basins might give us insight into the relative thickness of the cover material in these areas. We explore the geographic distribution of QCDs around the Utopia, Isidis and Acidalia basins and compare their location to geologic units and materials. We also compare evidence for relative thickness of cover material at the three basins.

A Comparison of Automated and Manual Crater Counting Techniques in Images of Elysium Planitia.

NASA Astrophysics Data System (ADS)

Plesko, C. S.; Brumby, S. P.; Asphaug, E.

2004-11-01

Surveys of impact craters yield a wealth of information about Martian geology, providing clues to the relative age, local composition and erosional history of the surface. Martian craters are also of intrinsic geophysical interest, given that the processes by which they form are not entirely clear, especially cratering in ice-saturated regoliths (Plesko et al. 2004, AGU) which appear common on Mars (Squyres and Carr 1986). However, the deluge of data over the last decade has made comprehensive manual counts prohibitive, except in select regions. Given that most small craters on Mars may be secondaries from a few very recent impact events (McEwen et al. in press, Icarus 2004), using select regions for age dating introduces considerable potential for sampling error. Automation is thus an enabling planetary science technology. In contrast to machine counts, human counts are prone to human decision making, thus not intrinsically reproducible. One can address human "noise" by averaging over many human counts (Kanefsky et al. 2001), but this multiplies the already laborious effort required. In this study, we test automated crater counting algorithms developed with the Los Alamos National Laboratory genetic programming suite GENIE (Harvey et al., 2002) against established manual counts of craters in Elysium Planitia, using MOC and THEMIS data. We intend to establish the validity of our method against well-regarded hand counts (Hartmann et al. 2000), and then apply it generally to larger regions of Mars. Previous work on automated crater counting used customized algorithms (Bierhaus et al. 2003, Burl et al.. 2001). Algorithms generated by genetic programming have the advantage of requiring little time or user effort to generate, so it is relatively easy to generate a suite of algorithms for varied terrain types, or to compare results from multiple algorithms for improved accuracy (Plesko et al. 2003).

Rayleigh Wave Ellipticity Modeling and Inversion for Shallow Structure at the Proposed InSight Landing Site in Elysium Planitia, Mars

NASA Astrophysics Data System (ADS)

Knapmeyer-Endrun, Brigitte; Golombek, Matthew P.; Ohrnberger, Matthias

2017-10-01

The SEIS (Seismic Experiment for Interior Structure) instrument onboard the InSight mission will be the first seismometer directly deployed on the surface of Mars. From studies on the Earth and the Moon, it is well known that site amplification in low-velocity sediments on top of more competent rocks has a strong influence on seismic signals, but can also be used to constrain the subsurface structure. Here we simulate ambient vibration wavefields in a model of the shallow sub-surface at the InSight landing site in Elysium Planitia and demonstrate how the high-frequency Rayleigh wave ellipticity can be extracted from these data and inverted for shallow structure. We find that, depending on model parameters, higher mode ellipticity information can be extracted from single-station data, which significantly reduces uncertainties in inversion. Though the data are most sensitive to properties of the upper-most layer and show a strong trade-off between layer depth and velocity, it is possible to estimate the velocity and thickness of the sub-regolith layer by using reasonable constraints on regolith properties. Model parameters are best constrained if either higher mode data can be used or additional constraints on regolith properties from seismic analysis of the hammer strokes of InSight's heat flow probe HP3 are available. In addition, the Rayleigh wave ellipticity can distinguish between models with a constant regolith velocity and models with a velocity increase in the regolith, information which is difficult to obtain otherwise.

High Resolution Imaging Science Experiment (HiRISE) observations of glacial and periglacial morphologies in the circum-Argyre Planitia highlands, Mars

USGS Publications Warehouse

Banks, Maria E.; McEwen, Alfred S.; Kargel, Jeffrey S.; Baker, Victor R.; Strom, Robert G.; Mellon, Michael T.; Gulick, Virginia C.; Keszthelyi, Laszlo; Herkenhoff, Kenneth E.; Pelletier, Jon D.; Jaeger, Windy L.

2008-01-01

The landscape of the Argyre Planitia and adjoining Charitum and Nereidum Montes in the southern hemisphere of Mars has been heavily modified since formation of the Argyre impact basin. This study examines morphologies in the Argyre region revealed in images acquired by the High Resolution Imaging Science Experiment (HiRISE) camera and discusses the implications for glacial and periglacial processes. Distinctive features such as large grooves, semicircular embayments in high topography, and streamlined hills are interpreted as glacially eroded grooves, cirques, and whalebacks or roche moutonnée, respectively. Large boulders scattered across the floor of a valley may be ground moraine deposited by ice ablation. Glacial interpretations are supported by the association of these features with other landforms typical of glaciated landscapes such as broad valleys with parabolic cross sections and stepped longitudinal profiles, lobate debris aprons interpreted as remnant debris covered glaciers or rock glaciers, and possible hanging valleys. Aligned boulders observed on slopes may also indicate glacial processes such as fluting. Alternatively, boulders aligned on slopes and organized in clumps and polygonal patterns on flatter surfaces may indicate periglacial processes, perhaps postglaciation, that form patterned ground. At least portions of the Argyre region appear to have been modified by processes of ice accumulation, glacial flow, erosion, sediment deposition, ice stagnation and ablation, and perhaps subsequent periglacial processes. The type of bedrock erosion apparent in images suggests that glaciers were, at times, wet based. The number of superposed craters is consistent with geologically recent glacial activity, but may be due to subsequent modification.

Mars Global Surveyor Approach Image

NASA Image and Video Library

1997-07-04

This image is the first view of Mars taken by the Mars Global Surveyor Orbiter Camera (MOC). It was acquired the afternoon of July 2, 1997 when the MGS spacecraft was 17.2 million kilometers (10.7 million miles) and 72 days from encounter. At this distance, the MOC's resolution is about 64 km per picture element, and the 6800 km (4200 mile) diameter planet is 105 pixels across. The observation was designed to show the Mars Pathfinder landing site at 19.4 N, 33.1 W approximately 48 hours prior to landing. The image shows the north polar cap of Mars at the top of the image, the dark feature Acidalia Planitia in the center with the brighter Chryse plain immediately beneath it, and the highland areas along the Martian equator including the canyons of the Valles Marineris (which are bright in this image owing to atmospheric dust). The dark features Terra Meridiani and Terra Sabaea can be seen at the 4 o`clock position, and the south polar hood (atmospheric fog and hazes) can be seen at the bottom of the image. Launched on November 7, 1996, Mars Global Surveyor will enter Mars orbit on Thursday, September 11 shortly after 6:00 PM PDT. After Mars Orbit Insertion, the spacecraft will use atmospheric drag to reduce the size of its orbit, achieving a circular orbit only 400 km (248 mi) above the surface in early March 1998, when mapping operations will begin. http://photojournal.jpl.nasa.gov/catalog/PIA00606

Geologic Map of the Hellas Region of Mars

USGS Publications Warehouse

Leonard, Gregory J.; Tanaka, Kenneth L.

2001-01-01

INTRODUCTION This geologic map of the Hellas region focuses on the stratigraphic, structural, and erosional histories associated with the largest well-preserved impact basin on Mars. Along with the uplifted rim and huge, partly infilled inner basin (Hellas Planitia) of the Hellas basin impact structure, the map region includes areas of ancient highland terrain, broad volcanic edifices and deposits, and extensive channels. Geologic activity recorded in the region spans all major epochs of martian chronology, from the early formation of the impact basin to ongoing resurfacing caused by eolian activity. The Hellas region, whose name refers to the classical term for Greece, has been known from telescopic observations as a prominent bright feature on the surface of Mars for more than a century (see Blunck, 1982). More recently, spacecraft imaging has greatly improved our visual perception of Mars and made possible its geologic interpretation. Here, our mapping at 1:5,000,000 scale is based on images obtained by the Viking Orbiters, which produced higher quality images than their predecessor, Mariner 9. Previous geologic maps of the region include those of the 1:5,000,000-scale global series based on Mariner 9 images (Potter, 1976; Peterson, 1977; King, 1978); the 1:15,000,000-scale global series based on Viking images (Greeley and Guest, 1987; Tanaka and Scott, 1987); and detailed 1:500,000-scale maps of Tyrrhena Patera (Gregg and others, 1998), Dao, Harmakhis, and Reull Valles (Price, 1998; Mest and Crown, in press), Hadriaca Patera (D.A. Crown and R. Greeley, map in preparation), and western Hellas Planitia (J.M. Moore and D.E. Wilhelms, map in preparation). We incorporated some of the previous work, but our map differs markedly in the identification and organization of map units. For example, we divide the Hellas assemblage of Greeley and Guest (1987) into the Hellas Planitia and Hellas rim assemblages and change the way units within these groupings are identified and mapped (table 1). The new classification scheme includes broad, geographically related categories and local, geologically and geomorphically related subgroups. Because of our mapping at larger scale, many of our map units were incorporated within larger units of the global-scale mapping (see table 1). Available Viking images of the Hellas region vary greatly in several aspects, which has complicated the task of producing a consistent photogeologic map. Best available image resolution ranges from about 30 to 300 m/pixel from place to place. Many images contain haze caused by dust clouds, and contrast and shading vary among images because of dramatic seasonal changes in surface albedo, opposing sun azimuths, and solar inclination. Enhancement of selected images on a computer-display system has greatly improved our ability to observe key geologic relations in several areas. Determination of the geologic history of the region includes reconstruction of the origin and sequence of formation, deformation, and modification of geologic units constituting (1) the impact-basin rim and surrounding highlands, (2) volcanic and channel assemblages on the northeast and south sides of the basin, (3) interior basin deposits, and (4) slope and surficial materials throughout the map area. Various surface modifications are attributed to volcanic, fluvial, eolian, mass-wasting, and possibly glacial and periglacial processes. Structures include basin faults (mostly inferred), wrinkle ridges occurring mainly in volcanic terrains and interior plains, volcanic collapse craters, and impact craters. Our interpretations in some cases rely on previous work, but in many significant cases we have offered new interpretations that we believe are more consistent with the observations documented by our mapping. Our primary intent for this mapping has been to elucidate the history of emplacement and modification of Hellas Planitia materials, which form the basis for analysis of their r

Emplacement of the youngest flood lava on Mars: A short, turbulent story

USGS Publications Warehouse

Jaeger, W.L.; Keszthelyi, L.P.; Skinner, J.A.; Milazzo, M.P.; McEwen, A.S.; Titus, T.N.; Rosiek, M.R.; Galuszka, D.M.; Howington-Kraus, E.; Kirk, R.L.

2010-01-01

Recently acquired data from the High Resolution Imaging Science Experiment (HiRISE), Context (CTX) imager, and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter (MRO) spacecraft were used to investigate the emplacement of the youngest flood-lava flow on Mars. Careful mapping finds that the Athabasca Valles flood lava is the product of a single eruption, and it covers 250,000 km2 of western Elysium Planitia with an estimated 5000-7500 km3 of mafic or ultramafic lava. Calculations utilizing topographic data enhanced with MRO observations to refine the dimensions of the channel system show that this flood lava was emplaced turbulently over a period of only a few to several weeks. This is the first well-documented example of a turbulently emplaced flood lava anywhere in the Solar System. However, MRO data suggest that this same process may have operated in a number of martian channel systems. The magnitude and dynamics of these lava floods are similar to the aqueous floods that are generally believed to have eroded the channels, raising the intriguing possibility that mechanical erosion by lava could have played a role in their incision. ?? 2009.

Emplacement of the youngest flood lava on Mars: A short, turbulent story

USGS Publications Warehouse

Jaeger, W.L.; Keszthelyi, L.P.; Skinner, J.A.; Milazzo, M.P.; McEwen, A.S.; Titus, T.N.; Rosiek, M.R.; Galuszka, D.M.; Howington-Kraus, E.; Kirk, R.L.

2009-01-01

Recently acquired data from the High Resolution Imaging Science Experiment (HiRISE), Context (CTX) imager, and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter (MRO) spacecraft were used to investigate the emplacement of the youngest flood-lava flow on Mars. Careful mapping finds that the Athabasca Valles flood lava is the product of a single eruption, and it covers 250,000 km2 of western Elysium Planitia with an estimated 5000-7500 km3 of mafic or ultramafic lava. Calculations utilizing topographic data enhanced with MRO observations to refine the dimensions of the channel system show that this flood lava was emplaced turbulently over a period of only a few to several weeks. This is the first well-documented example of a turbulently emplaced flood lava anywhere in the Solar System. However, MRO data suggest that this same process may have operated in a number of martian channel systems. The magnitude and dynamics of these lava floods are similar to the aqueous floods that are generally believed to have eroded the channels, raising the intriguing possibility that mechanical erosion by lava could have played a role in their incision.

Geological mapping of Sputnik Planitia on Pluto

NASA Astrophysics Data System (ADS)

White, Oliver L.; Moore, Jeffrey M.; McKinnon, William B.; Spencer, John R.; Howard, Alan D.; Schenk, Paul M.; Beyer, Ross A.; Nimmo, Francis; Singer, Kelsi N.; Umurhan, Orkan M.; Stern, S. Alan; Ennico, Kimberly; Olkin, Cathy B.; Weaver, Harold A.; Young, Leslie A.; Cheng, Andrew F.; Bertrand, Tanguy; Binzel, Richard P.; Earle, Alissa M.; Grundy, Will M.; Lauer, Tod R.; Protopapa, Silvia; Robbins, Stuart J.; Schmitt, Bernard; New Horizons Science Team

2017-05-01

The geology and stratigraphy of the feature on Pluto informally named Sputnik Planitia is documented through geologic mapping at 1:2,000,000 scale. All units that have been mapped are presently being affected to some degree by the action of flowing N2 ice. The N2 ice plains of Sputnik Planitia display no impact craters, and are undergoing constant resurfacing via convection, glacial flow and sublimation. Condensation of atmospheric N2 onto the surface to form a bright mantle has occurred across broad swathes of Sputnik Planitia, and appears to be partly controlled by Pluto's obliquity cycles. The action of N2 ice has been instrumental in affecting uplands terrain surrounding Sputnik Planitia, and has played a key role in the disruption of Sputnik Planitia's western margin to form chains of blocky mountain ranges, as well in the extensive erosion by glacial flow of the uplands to the east of Sputnik Planitia.

Magnetite Equation of State: Implications for Mars' Interior and Magnetization

NASA Astrophysics Data System (ADS)

Gant, P.; Walsh, J.; Lazarz, J. D.; Jacobsen, S. D.; Jurdy, D. M.

2017-12-01

Mars once had a global magnetic field, although it no longer has an active dynamo. Mars Global Surveyor (MGS) unexpectedly measured a strongly magnetized crust. However, the magnetic carrier as well as the nature and depth of magnetization remain unknown. Downward continuation of the surface magnetization suggests the possibility of great depth of magnetization, as much as 100-200 km, far exceeding that of Earth's. The interior composition and structure of Mars remain unknown. Magnetite offers a likely candidate for Martian magnetization. Experiments with magnetite crystals - one naturally-occurring, the other a laboratory-fabricated single domain crystal, determine its equation of state. NASA's upcoming InSight (INterior Exploration using Seismic Investigations, Geodesy, and Heat Transport) mission to Mars will be the first dedicated to study of the Martian interior. It will land in the Elysium Planitia with a 3-component broadband and short period seismometer, heatflow probe, and a magnetometer to monitor the local, atmospheric, and crustal magnetic field. The planned InSight measurements of Martian heatflow will establish its current temperature gradient. The first step in understanding Mars' magnetization requires knowing both temperature and pressure conditions for its interior, along with the equation of state for magnetite - and other possible magnetic minerals. Laboratory experiments with a range of compositions for the Martian interior could provide critical comparisons with the InSight mission's seismic data.

MOLA Global roughness map of Mars

NASA Technical Reports Server (NTRS)

2000-01-01

The median of slopes in 35-km windows indicate the typical roughness on 300-meter baselines. The rougher nature of the heavily cratered terrain in the Southern Hemisphere is apparent, as well as that of Valles Marineris (12S, 289E) canyon walls and the Olympus Mons (18N, 227E) aureole deposits. The Northern Lowlands are smooth, especially Amazonis Planitia (16N, 202E), a region to the west of Olympus Mons, were typical median slopes on these baselines are often smaller than 0.1 degree. A shaded relief map of the topography is overlaid is monochrome.

First Direct Detection of Clay Minerals on Mars

NASA Technical Reports Server (NTRS)

Singer, R. B.; Owensby, P. D.; Clark, R. N.

1985-01-01

Magnesian clays or clay-type minerals were conclusively detected in the martian regolith. Near-IR spectral observations of Mars using the Mauna Kea 2.2-m telescope show weak but definite absorption bands near microns. The absorption band positions and widths match those produced by combined OH stretch and Mg-OH lattice modes and are diagnostic of minerals with structural OH such as clays and amphiboles. Likely candidate minerals include serpentine, talc, hectorite, and sponite. There is no spectral evidence for aluminous hydroxylated minerals. No distinct band occurs at 2.55 microns, as would be expected if carbonates were responsible for the 2.35 micron absorption. High-albedo regions such as Elysium and Utopia have the strongest bands near 2.35 microns, as would be expected for heavily weathered soils. Low-albedo regions such as Iapygia show weaker but distinct bands, consistent with moderate coatings, streaks, and splotches of bright weathered material. In all areas observed, the 2.35-micron absorption is at least three times weaker than would be expected if well-crystallized clay minerals made up the bulk of bright soils on Mars.

Did Martian Meteorites Come From These Sources?

NASA Astrophysics Data System (ADS)

Martel, L. M. V.

2007-01-01

Large rayed craters on Mars, not immediately obvious in visible light, have been identified in thermal infrared data obtained from the Thermal Emission Imaging System (THEMIS) onboard Mars Odyssey. Livio Tornabene (previously at the University of Tennessee, Knoxville and now at the University of Arizona, Tucson) and colleagues have mapped rayed craters primarily within young (Amazonian) volcanic plains in or near Elysium Planitia. They found that rays consist of numerous chains of secondary craters, their overlapping ejecta, and possibly primary ejecta from the source crater. Their work also suggests rayed craters may have formed preferentially in volatile-rich targets by oblique impacts. The physical details of the rayed craters and the target surfaces combined with current models of Martian meteorite delivery and cosmochemical analyses of Martian meteorites lead Tornabene and coauthors to conclude that these large rayed craters are plausible source regions for Martian meteorites.

Which Way is Up?

NASA Image and Video Library

2014-10-29

This image NASA Mars Reconnaissance Orbiter shows an impact crater that was cut by lava in the Elysium Planitia region of Mars. It looks relatively flat, with a shallow floor, rough surface texture, and possible cooling cracks seem to indicate that the crater was partially filled with lava. The northern part of the image also shows a more extensive lava flow deposit that surrounds the impact ejecta of the largest impact crater in the image. Which way did the lava flow? It might appear that the lava flowed from the north through the channel into the partially filled crater. However, if you look at the anaglyph with your red and blue 3D glasses, it becomes clear that the partially filled crater sits on top of the large crater's ejecta blanket, making it higher than the lava flow to the north. Since lava does not flow uphill, that means the explanation isn't so simple. http://photojournal.jpl.nasa.gov/catalog/PIA18887

Preliminary results from the Viking orbiter imaging experiment

USGS Publications Warehouse

Carr, M.H.; Masursky, H.; Baum, W.A.; Blasius, K.R.; Briggs, G.A.; Cutts, J.A.; Duxbury, T.; Greeley, R.; Guest, J.E.; Smith, B.A.; Soderblom, L.A.; Veverka, J.; Wellman, J.B.

1976-01-01

During its first 30 orbits around Mars, the Viking orbiter took approximately 1000 photographic frames of the surface of Mars with resolutions that ranged from 100 meters to a little more than 1 kilometer. Most were of potential landing sites in Chryse Planitia and Cydonia and near Capri Chasma. Contiguous high-resolution coverage in these areas has led to an increased understanding of surface processes, particularly cratering, fluvial, and mass-wasting phenomena. Most of the surfaces examined appear relatively old, channel features abound, and a variety of features suggestive of permafrost have been identified. The ejecta patterns around large craters imply that fluid flow of ejecta occurred after ballistic deposition. Variable features in the photographed area appear to have changed little since observed 5 years ago from Mariner 9. A variety of atmospheric phenomena were observed, including diffuse morning hazes, both stationary and moving discrete white clouds, and wave clouds covering extensive areas.

Preliminary Results from the Viking X-ray Fluorescence Experiment: The First Sample from Chryse Planitia, Mars.

PubMed

Toulmin, P; Clark, B C; Baird, A K; Keil, K; Rose, H J

1976-10-01

Iron, calcium, aluminum, silicon, and sulfur are major elements in the first surface sample of Mars that has been analyzed by the Viking x-ray fluorescence spectrometer. Titanium is present in minor quantities. This is consistent with the sample being a mixture of fine silicate and oxide mineral grains, with a significant proportion of sulfates, possibly hydrated. Ferric oxide is regarded as the red pigmenting agent on the martian surface, but if it coats silicate grains, the coatings must be very thin (

Preliminary results from the Viking X-ray fluorescence experiment - The first sample from Chryse Planitia, Mars

NASA Technical Reports Server (NTRS)

Toulmin, P., III; Rose, H. J., Jr.; Clark, B. C.; Baird, A. K.; Keil, K.

1976-01-01

Iron, calcium, aluminum, silicon, and sulfur are major elements in the first surface sample of Mars that has been analyzed by the Viking X-ray fluorescence spectrometer. Titanium is present in minor quantities. This is consistent with the sample's being a mixture of fine silicate and oxide mineral grains, with a significant proportion of sulfates, possibly hydrated. Ferric oxide is regarded as the red pigmenting agent on the Martian surface, but if it coats silicate grains, the coatings must be very thin or discontinuous. A high abundance of Fe, relatively low abundances of Al, Rb, Sr, and Zr, and a high Ca/K ratio are distinctive features of the spectra. Preliminary determinations indicate the following abundances (as percentages by weight): Fe, 14 plus or minus 2; Ti, less than 1; S, 2 to 5; the Ca/K ratio by weight is greater than 5.

Preliminary results from the viking x-ray fluorescence experiment: The first sample from chryse planitia, Mars

USGS Publications Warehouse

Toulmin, P.; Clark, B. C.; Baird, A.K.; Keil, Klaus; Rose, H.J.

1976-01-01

Iron, calcium, aluminum, silicon, and sulfur are major elements in the first surface sample of Mars that has been analyzed by the Viking x-ray fluorescence spectrometer. Titanium is present in minor quantities. This is consistent with the sample being a mixture of fine silicate and oxide mineral grains, with a significant proportion of sulfates, possibly hydrated. Ferric oxide is regarded as the red pigmenting agent on the martian surface, but if it coats silicate grains, the coatings must be very thin (??? 2 micrometers) or discontinuous. A high abundance of Fe, relatively low abundances of Al, Rb, Sr, and Zr, and a high Ca/K ratio are distinctive features of the spectra. Preliminary determinations indicate the following abundances (as percentages by weight): Fe, 14 ?? 2; Ti < 1; S, 2 to 5; the Ca/K ratio by weight is greater than 5.

The origin and evolution of terrestrial and Martian rock labyrinths

NASA Technical Reports Server (NTRS)

Brook, G. A.

1984-01-01

The morphological characteristics and evolutionary development of rock labyrinths on Earth (in sandstone, volcanics, and carbonates) are compared with those on Mars. On Earth rock labyrinths originate as parallel, an echelon, or intersecting narrow grabens, or develop where fault and joint networks are selectively eroded. Labyrinths frequently contain both downfaulted and erosional elements. Closed labyrinths contain depressions; open labyrinths do not, they are simple part of a fluvial network generally of low order. As closed labyrinths made up of intersecting grabens or made up of connected erosional depressions are extremely common on Mars, the research focussed on an understanding of these labyrinth types. Field investigations were carried out in Canyonlands National Park, Utah, and in the Chirachahua Mountains of Arizona. Martian labyrinths were investigated using Viking orbiter images. In addition, research was undertaken on apparent thermokarst features in Lunae Planum and Chryse Planitia where closed depressions are numerous and resemble atlas topography.

Mud volcanoes of trinidad as astrobiological analogs for martian environments.

PubMed

Hosein, Riad; Haque, Shirin; Beckles, Denise M

2014-10-13

Eleven onshore mud volcanoes in the southern region of Trinidad have been studied as analog habitats for possible microbial life on Mars. The profiles of the 11 mud volcanoes are presented in terms of their physical, chemical, mineralogical, and soil properties. The mud volcanoes sampled all emitted methane gas consistently at 3% volume. The average pH for the mud volcanic soil was 7.98. The average Cation Exchange Capacity (CEC) was found to be 2.16 kg/mol, and the average Percentage Water Content was 34.5%. Samples from three of the volcanoes, (i) Digity; (ii) Piparo and (iii) Devil's Woodyard were used to culture bacterial colonies under anaerobic conditions indicating possible presence of methanogenic microorganisms. The Trinidad mud volcanoes can serve as analogs for the Martian environment due to similar geological features found extensively on Mars in Acidalia Planitia and the Arabia Terra region.

Mud Volcanoes of Trinidad as Astrobiological Analogs for Martian Environments

PubMed Central

Hosein, Riad; Haque, Shirin; Beckles, Denise M.

2014-01-01

Eleven onshore mud volcanoes in the southern region of Trinidad have been studied as analog habitats for possible microbial life on Mars. The profiles of the 11 mud volcanoes are presented in terms of their physical, chemical, mineralogical, and soil properties. The mud volcanoes sampled all emitted methane gas consistently at 3% volume. The average pH for the mud volcanic soil was 7.98. The average Cation Exchange Capacity (CEC) was found to be 2.16 kg/mol, and the average Percentage Water Content was 34.5%. Samples from three of the volcanoes, (i) Digity; (ii) Piparo and (iii) Devil’s Woodyard were used to culture bacterial colonies under anaerobic conditions indicating possible presence of methanogenic microorganisms. The Trinidad mud volcanoes can serve as analogs for the Martian environment due to similar geological features found extensively on Mars in Acidalia Planitia and the Arabia Terra region. PMID:25370529

Evidence for Weak Crustal Magnetic Fields over the Hellas, Chryse, and Acidalia Planitiae

NASA Astrophysics Data System (ADS)

Lee, C. O.; Mitchell, D. L.; Lillis, R.; Lin, R. P.; Reme, H.; Cloutier, P. A.; Acuna, M. H.

2003-04-01

The Electron Reflectometer (ER) onboard Mars Global Surveyor (MGS) detected a plasma boundary between the ionosphere and the solar wind as the latter is diverted around and past the planet [Mitchell et al., GRL, 27, 1871, 2000; Mitchell et al., JGR, 106, 23419, 2001]. Above this boundary the 10-1000 eV electron population is dominated by solar wind electrons, while below the boundary it is dominated by ionospheric photoelectrons. This "photoelectron boundary", or PEB, is sensitive to pressure variations and moves vertically in response to changes in the ionospheric pressure from below and the solar wind pressure from above. The PEB is also sensitive to crustal magnetic fields, which locally increase the total ionospheric pressure and positively bias the PEB altitude. We have empirically modeled and removed systematic variations in the PEB altitude associated with the solar wind interaction, thus isolating perturbations caused by crustal magnetic fields. A map of the PEB altitude perturbations closely resembles maps of the horizontal component of the crustal magnetic field measured at 400 km by the MGS Magnetometer (MAG). We find a PEB altitude bias over the Hellas basin that is consistent with a horizontal magnetic field with an intensity of several nanotesla at 400 km altitude. This is compatible with upper limits to the horizontal crustal field strength set by MGS MAG measurements. Since there is no evidence for significant crustal magnetic sources within the basin from MAG data obtained during aerobraking [Acuna et al. Science, 284, 790, 1999] or from electron reflection data obtained in the mapping orbit [Lillis et al., this conference], the most likely explanation is that the observed horizontal field originates from sources around the Hellas perimeter. No detectable PEB or magnetic signature is observed over the younger Argyre and Isidis Basins. There is also evidence for a significant enhancement (several nanoteslas) in the crustal field strength over Chryse Planitia and much of Acidalia Planitia, which are thought to contain hundreds of meters of material from the main outflow channels on Mars [Carr, Lunar Planetary Sci., 18, 155, 1987]. These fields appear to extend northward from a group of crustal magnetic sources along the dichotomy boundary that were mapped by the MGS Magnetometer.

Physical properties of Deucalionis, Eos, Xanthe-type units in the central equatorial region of Mars

NASA Technical Reports Server (NTRS)

Strickland, Edwin L., III

1992-01-01

Classification and mapping of surficial units in the central equatorial region of Mars (30 degrees N to 20 degrees S, 57 degrees E to 75 degrees W) using enhanced color images and Mars Consortium data, identified three distinct, high albedo, relatively red surficial units in regions with intermediate to high thermal inertias. These units have distinctive properties and morphologies, occur in different, well-defined areas, and show different seasonal and secular patterns of albedo change. Deucalionis units occupy the classical albedo area of Deucalionis Regio, south of Meridiani Sinus and Sabaeus Sinus, and adjacent areas. Eos forms a bright band that separates the dark, relatively blue Meridiani-type units that dominate the southern part of the study area from intermediate albedo, relatively red Oxia units common in the north. Xanthe forms moderately bright, relatively red, Type 1B crater-streaks and uniform sheet-deposits in and adjacent to parts of Chryse Planitia, including the Viking 1 landing site. Xanthe is always associated with Oxia deposits, and has significantly lower albedos than the Eos materials, which it can be confused with.

Radar characteristics of Viking 1 landing sites

USGS Publications Warehouse

Tyler, G.L.; Campbell, D.B.; Downs, G.S.; Green, R.R.; Moore, H.J.

1976-01-01

Radar observations of Mars at centimeter wavelengths in May, June, and July 1976 provided estimates of surface roughness and reflectivity in three potential landing areas for Viking 1. Surface roughness is characterized by the distribution of surface landing slopes or tilts on lateral scales of the order of 1 to 10 meters; measurements of surface reflectivity are indicators of bulk surface density in the uppermost few centimeters. By these measures, the Viking 1 landing site at 47.5??W, 22.4??N is rougher than the martian average, although it may be near the martian average for elevations accessible to Viking, and is estimated to be near the Mars average in reflectivity. The AINW site at the center of Chryse Planitia, 43.5??W, 23.4??N, may be an area of anomalous radar characteristics, indicative of extreme, small-scale roughness, very low surface density, or a combination of these two characteristics. Low signal-to-noise ratio observations of the original Chryse site at 34??W, 19.5??N indicate that that area is at least twice as rough as the Mars average.

Selection of the landing site in Isidis Planitia of Mars probe Beagle 2

NASA Astrophysics Data System (ADS)

Bridges, J. C.; Seabrook, A. M.; Rothery, D. A.; Kim, J. R.; Pillinger, C. T.; Sims, M. R.; Golombek, M. P.; Duxbury, T.; Head, J. W.; Haldemann, A. F. C.; Mitchell, K. L.; Muller, J.-P.; Lewis, S. R.; Moncrieff, C.; Wright, I. P.; Grady, M. M.; Morley, J. G.

2003-01-01

This paper describes selection and characterization of the landing site for the Mars 2004 Beagle 2 mission. The site is within Isidis Planitia between 10°-12°N, 266°-274°W, centered at 11.6°N, 269.5°W. This is at low elevation (-3600 to -3900 m MOLA), is flat (MOLA RMS slope = 0.57°), radar data suggest a smoother surface at decimeter to meter scales than the Pathfinder site and it has a moderate rock abundance (2-17%, mean 11%). In addition to this, Isidis shows evidence for concentration and remobilization of volatiles. In particular, the basin contains conical landforms. We favor models involving the formation of tuff cones during magma-ice interaction. Structures identified as dykes in MOC images may be remnants of magma conduits. The pattern of bulk thermal inertia in Isidis (higher values of 500 Jm-2s-0.5K-1 around the SW-S-E margin decreasing toward the center and north) suggests that an influx of sediment spread from the Noachian areas around the southern half of the basin over the basin floor. The coarse, higher thermal inertia material was deposited closest to the sediment source. The variable state of erosion of the tuff cones suggests that they formed intermittently over a long period of time during Amazonian and possibly Hesperian epochs. Geologically recent resurfacing of Isidis has also occurred by aeolian processes, and this is shown by a deficit in impact craters <120 m diameter. The proportion of rocky material is predicted to be slightly less than the Viking and Pathfinder sites, but there will probably be more duricrust.

Initial results from radio occultation measurements with the Mars Reconnaissance Orbiter: A nocturnal mixed layer in the tropics and comparisons with polar profiles from the Mars Climate Sounder

NASA Astrophysics Data System (ADS)

Hinson, David P.; Asmar, Sami W.; Kahan, Daniel S.; Akopian, Varoujan; Haberle, Robert M.; Spiga, Aymeric; Schofield, John T.; Kleinböhl, Armin; Abdou, Wedad A.; Lewis, Stephen R.; Paik, Meegyeong; Maalouf, Sami G.

2014-11-01

The Mars Reconnaissance Orbiter (MRO) performs radio occultation (RO) measurements on selected orbits, generally once per day. We have retrieved atmospheric profiles from two subsets of data, yielding a variety of new results that illustrate the scientific value of the observations. One set of measurements sounded the tropics in northern summer at a local time ∼1 h before sunrise. Some of these profiles contain an unexpected layer of neutral stability with a depth of ∼4 km and a pressure at its upper boundary of ∼160 Pa. The mixed layer is bounded above by a temperature inversion and below by another strong inversion adjacent to the surface. This type of structure is observed near Gale Crater, in the Tharsis region, and at a few other locations, whereas profiles in Amazonis Planitia and Elysium Planitia show no sign of a detached mixed layer with an overlying inversion. We supplemented the measurements with numerical simulations by the NASA Ames Mars General Circulation Model, which demonstrate that water ice clouds can generate this distinctive type of temperature structure through their influence on radiative transfer at infrared wavelengths. In particular, the simulations predict the presence of a nocturnal cloud layer in the Tharsis region at a pressure of ∼150 Pa (∼10 km above the surface), and the nighttime radiative cooling at cloud level is sufficient to produce a temperature inversion above the cloud as well as convective instability below the cloud, consistent with the observations. The second set of measurements sounded mid-to-high northern latitudes in spring, when carefully coordinated observations by the MRO Mars Climate Sounder (MCS) are also available. The differences between the RO and MCS temperature profiles are generally consistent with the expected performance of the two instruments. Within this set of 21 comparisons the average temperature difference is less than 1 K where the aerosol opacities are smaller than 10-3km-1 , at pressures of 10-50 Pa, whereas it increases to ∼2 K where the aerosol opacities exceed this threshold, at pressures of 50-300 Pa. The standard deviation of the temperature difference is ∼2 K, independent of pressure. The second set of RO measurements also provides unique information about the stability of the annual CO2 cycle and the dynamics near the edge of the seasonal CO2 ice cap.

Chaotic Mountain Blocks in Pluto’s Sputnik Planitia

NASA Astrophysics Data System (ADS)

Singer, Kelsi N.; Knight, Katherine I.; Stern, S. Alan; Olkin, Catherine; Grundy, William M.; McKinnon, William B.; Moore, Jeffrey M.; Schenk, Paul M.; Spencer, John R.; Weaver, Harold A.; Young, Leslie; Ennico, Kimberly; New Horizons Geology, Geophysics and Imaging Science Theme Team, The New Horizons Surface Composition Science Theme Team

2017-10-01

One of the first high-resolution Pluto images returned by New Horizons displayed a collection of tall, jagged peaks rising out of the large nitrogen ice sheet informally known as Sputnik Planitia (SP). This mountain range was later revealed to be one of several along the western edge of SP. The mountains are several hundred broken-up blocks of Pluto’s primarily water ice lithosphere and some retain surface terrains similar to the nearby intact crust surrounding SP. Water ice with some fractures or porosity is likely >5% less dense than solid N2 ice at Pluto’s temperatures. Thus it is possible the blocks are, or were, floating icebergs or at least partially suspended to the point that some blocks appear to be tilted as if they have faltered (Moore et al., 2016, Science, 351, 1284-1293).We analyze four mountain ranges on the western edge of SP and compare to chaotic terrains on Europa and Mars. The blocks on Pluto have angular planforms but we characterize their size using block surface area converted to an equivalent circular diameter. Topography was used to define block extents. The blocks range in size from 3-30 km in diameter, with a mode of ~8-10 km. Blocks range from 0.2-3.8 km in height, and block height generally increases with block diameter. One or more dark layers can be identified in a few scarp faces, and are at a similar depth to each other and to layers seen in fault and crater walls elsewhere on Pluto. A large N-S trending fault system runs tangential to SP and may be the source of crustal disruption on the western side.On Europa and Mars block sizes vary greatly between different chaos regions, but Conamara Chaos has an average block size of ~5 km in diameter, smaller than that typically seen on Pluto. Also the blocks often transition into fractured terrain still connected to the surround lithosphere at the periphery of the chaos regions. The source regions for the blocks are more obvious on Europa and Mars. Additionally the block heights on Europa and Mars generally do not increase with block size. Thus, the main mechanism of crustal breakup is likely different between these bodies.

The Martian Goes To College: Open Inquiry with Science Fiction in the Classroom.

NASA Astrophysics Data System (ADS)

Beatty, L.; Patterson, J. D.

2015-12-01

Storytelling is an ancient art; one that can get lost in the reams of data available in a typical geology or astronomy classroom. But storytelling draws us to a magical place. Our students, with prior experience in either a geology or astronomy course, were invited to explore Mars in a special topics course at Johnson County Community College through reading The Martian by Andy Weir. As they traveled with astronaut Mark Watney, the students used Google Mars, Java Mission-planning and Analysis for Remote Sensing (JMARS), and learning modules from the Mars for Earthlings web site to investigate the terrain and the processes at work in the past and present on Mars. Our goal was to apply their understanding of processes on Earth in order to explain and predict what they observed on Mars courtesy of the remote sensing opportunities available from Viking, Pathfinder, the Mars Exploration Rovers, and Maven missions; sort of an inter-planetary uniformitarianism. Astronaut Mark Watney's fictional journey from Acidalia Planitia to Schiaparelli Crater was analyzed using learning modules in Mars for Earthlings and exercises that we developed based on Google Mars, JMARS, Rotating Sky Explorer, and Science Friday podcasts. Each student also completed an individual project that either focused on a particular region that Astronaut Mark Watney traveled through or a problem that he faced. Through this open-inquiry learning style, they determined some processes that shaped Mars such as crater impacts, volcanism, fluid flow, mass movement, and groundwater sapping and also investigated the efficacy of solar energy as a power source based on location and the likelihood of regolith potential as a mineral matter source for soil.

Midlatitude ice-rich ground on mars as a target in the search for evidence of life and for in situ resource utilization on human missions.

PubMed

Heldmann, J L; Schurmeier, L; McKay, C; Davila, A; Stoker, C; Marinova, M; Wilhelm, M B

2014-02-01

Midlatitude ground ice on Mars is of significant scientific interest for understanding the history and evolution of ice stability on Mars and is relevant for human exploration as a possible in situ resource. For both science and exploration, assessing the astrobiological potential of the ice is important in terms of (1) understanding the potential for life on Mars and (2) evaluating the presence of possible biohazards in advance of human exploration. In the present study, we review the evidence for midlatitude ground ice on Mars, discuss the possible explanations for its occurrence, and assess its potential habitability. During the course of study, we systematically analyzed remote-sensing data sets to determine whether a viable landing site exists in the northern midlatitudes to enable a robotic mission that conducts in situ characterization and searches for evidence of life in the ice. We classified each site according to (1) presence of polygons as a proxy for subsurface ice, (2) presence and abundance of rough topographic obstacles (e.g., large cracks, cliffs, uneven topography), (3) rock density, (4) presence and abundance of large boulders, and (5) presence of craters. We found that a suitable landing site exists within Amazonis Planitia near ground ice that was recently excavated by a meteorite impact.

Hot Dog and Butterfly, Nereidum Montes

NASA Technical Reports Server (NTRS)

1999-01-01

Some of the pictures returned from Mars by the Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor (MGS) spacecraft show features that--at a glance--resemble familiar, non-geological objects on Earth. For example, the picture above at the left shows several low, relatively flat-topped hills (mesas) on the floor of a broad valley among the mountains of the Nereidum Montes region, northeast of Argyre Planitia. One of the mesas seen here looks like half of a butterfly (upper subframe on right). Another hill looks something like a snail or a hot dog wrapped and baked in a croissant roll (lower subframe on right). These mesas were formed by natural processes and are most likely the eroded remnants of a formerly more extensive layer of bedrock. In the frame on the left, illumination is from the upper left and the scene covers an area 2.7 km (1.7 miles) wide by 6.8 km (4.2 miles) high. The 'butterfly' is about 800 meters (875 yards) in length and the 'hot dog' is about 1 km (0.62 miles) long.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Tidal Excitation of the Core Dynamo of Mars

NASA Astrophysics Data System (ADS)

Seyed-Mahmoud, B.; Arkani-Hamed, J.; Aldridge, K.

2007-05-01

The lack of magnetic anomalies inside the giant impact basins Hellas, Isidis, Utopia and Argyre, inside the northern low lands, over the Tharsis bulge, and over the Tharsis and Olympus mounts suggests that the core field of Mars ceased to exist by about 4 Gyr ago, almost when the giant basins were formed. On the other hand, the giant basins are located on a great circle, implying that the basins were likely produced by fragments of a large asteroid that broke apart as it entered the Roche limit of Mars. This scenario offers a causative relationship for the apparent coincidence of the formation of the giant basins and the cessation of the core dynamo. We suggest that the core dynamo was excited by tidally driven elliptical instability in the Martian core. The breaking of the asteroid and its final impact on Mars eliminated the excitation and thus killed the dynamo. We show that a retrograde asteroid captured in a Keplerian orbit around Mars at a distance of about 50,000-100,000 km could orbit Mars for several hundreds of millions of years before impacting the planet due to the tidal coupling of the asteroid and Mars. Because of relatively very short growth time of the elliptical instability, less than 50,000 years, the asteroid was capable of retaining the elliptical instability and energizing the core dynamo for a geologically long period prior to 4 Ga. Our laboratory observations of a parametric instability of a rotating incompressible fluid, contained in a flexible-walled spherical cavity, confirm the possibility that an early Martian dynamo could have been powered by tidal straining.

Topographic Change of the Dichotomy Boundary Suggested by Crustal Inversion

NASA Technical Reports Server (NTRS)

Neumann, G. A.

2004-01-01

Linear negative gravity anomalies in Acidalia Planitia along the eastern edge of Tempe Terra and along the northern edge of Arabia Terra have been noted in Mars Global Surveyor gravity fields. Once proposed to represent buried fluvial channels, it is now believed that these gravity troughs mainly arise from partial compensation of the hemispheric dichotomy topographic scarp. A recent inversion for crustal structure finds that mantle compensation of the scarp is offset from the present-day topographic expression of the dichotomy boundary. The offset suggests that erosion or other forms of mass wasting occurred after lithosphere thickened and no longer accomodated topographic change through viscous relaxation.

Transient Slope Lineae Formation in a Well-Preserved Crater

NASA Image and Video Library

2017-11-20

This enhanced color image from NASA's Mars Reconnaissance Orbiter (MRO) shows what are called "recurring slope lineae"s in Tivat Crater. The narrow, dark flows descend downhill (towards the upper left). Analysis shows that the flows all end at approximately the same slope, which is similar to the angle of repose for sand. RSL are mostly found on steep rocky slopes in dark regions of Mars, such as the southern mid-latitudes, Valles Marineris near the equator, and in Acidalia Planitia on the northern plains. The appearance and growth of these features resemble seeping liquid water, but how they form remains unclear, and this research demonstrated that the RSL flows seen by HiRISE are likely moving granular material like sand and dust. These findings indicate that present-day Mars may not have a significant volume of liquid water. The water-restricted conditions that exist on Mars would make it difficult for Earth-like life to exist near the surface of the planet. The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 25.6 centimeters (10.8 inches) per pixel (with 1 x 1 binning); objects on the order of 77 centimeters (30.3 inches) across are resolved.] North is up. https://photojournal.jpl.nasa.gov/catalog/PIA22114

Characterizing of a Mid-Latitude Ice-Rich Landing Site on Mars to Enable in Situ Habitability Studies

NASA Technical Reports Server (NTRS)

Heldmann, J.; Schurmeier, L. R.; Wilhelm, M.; Stoker, C.; McKay, C.; Davila, A.; Marinova, M.; Karcz, J.; Smith, H.

2012-01-01

We suggest an ice-rich landing site at 188.5E 46.16N within Amazonis Planitia as a candidate location to support a Mars lander mission equipped to study past habitability and regions capable of preserving the physical and chemical signs of life and organic matter. Studies of the ice-rich subsurface on Mars are critical for several reasons. The subsurface environment provides protection from radiation to shield organic and biologic compounds from destruction. The ice-rich substrate is also ideal for preserving organic and biologic molecules and provides a source of H2O for biologic activity. Examination of martian ground ice can test several hypotheses such as: 1) whether ground ice supports habitable conditions, 2) that ground ice can preserve and accumulate organic compounds, and 3) that ice contains biomolecules evident of past or present biological activity on Mars. This Amazonis site, located near the successful Viking Lander 2, shows indirect evidence of subsurface ice (ubiquitous defined polygonal ground, gamma ray spectrometer hydrogen signature, and numerical modeling of ice stability) and direct evidence of exposed subsurface ice. This site also provides surface conditions favorable to a safe landing including no boulders, low rock density, minimal rough topography, and few craters.

Hellas as a Possible Site of Ancient Ice-Covered Lakes on Mars

NASA Technical Reports Server (NTRS)

Moore, Jeffrey M.; Wilhelms, Don E.; DeVincenzi, Donald (Technical Monitor)

2002-01-01

Based on topographic, morphologic, and stratigraphic evidence, we propose that ancient water-laid sediment is the dominant component of deposits within Hellas Planitia, Mars. Multiply layered sediment is manifested by alternating benches and scarps visible in Mars Orbiting Camera narrow-angle (MOC NA) images. Viking Orbiter camera and MOC NA images were used to map contacts and stratigraphically order the different materials units within Hellas. Mar's Orbiting Laser Altimeter (MOLA) data reveal that the contacts of these sedimentary units, as well as a number of scarps or other abrupt changes in landscape texture, trace contours of constant elevation for thousands of km, and in one case all around the basin. Channels, consensually interpreted to be cut by water, lead into the basin. MOLA results indicate that the area encompassed by greater Hellas' highest closed contour is nearly one-fifth that of the entire northern plains, making the Hellas 'drainage' area much larger than previously reported. If lakes formed under climatic conditions similar to the modern Martian climate, they would develop thick ice carapaces, then the lakes would eventually sublimate away. Two units within Hellas exhibit a reticulate or honeycomb pattern we speculate are impressions made by lake-lowered ice blocks grounding into initially soft mud.

Hellas as a possible site of ancient ice-covered lakes on Mars

USGS Publications Warehouse

Moore, Johnnie N.; Wilhelms, D.E.

2001-01-01

Based on topographic, morphologic, and stratigraphic evidence, we propose that ancient water-laid sediment is the dominant component of deposits within Hellas Planitia, Mars. Multiple-layered sediment is manifested by alternating benches and scarps visible in Mars orbiting camera narrow-angle (MOC NA) images. Viking Orbiter camera and MOC NA images were used to map contacts and stratigraphically order the different materials units within Hellas. Mars orbiting laser altimeter (MOLA) data reveal that the contacts of these sedimentary units, as well as a number of scarps or other abrupt changes in landscape texture, trace contours of constant elevation for thousands of km, and in one case all around the basin. Channels, consensually interpreted to be cut by water, lead into the basin. MOLA results indicate that the area encompassed by greater Hellas' highest closed contour is nearly one-fifth that of the entire northern plains, making the Hellas "drainage" area much larger than previously reported. If lakes formed under climatic conditions similar to the modern Martian climate, they would develop thick ice carapaces, then the lakes would eventually sublimate away. Two units within Hellas exhibit a reticulate or honeycomb pattern, which we speculate are impressions made by lake-lowered ice blocks grounding into initially soft mud.

Block Distribution Analysis of Impact Craters in the Tharsis and Elysium Planitia Regions on Mars

NASA Astrophysics Data System (ADS)

Button, N.; Karunatillake, S.; Diaz, C.; Zadei, S.; Rajora, V.; Barbato, A.; Piorkowski, M.

2017-12-01

The block distribution pattern of ejecta surrounding impact craters reveals clues about their formation. Using images from High Resolution Imaging Science Experiment (HiRISE) image onboard the Mars Reconnaissance Orbiter (MRO), we indentified two rayed impact craters on Mars with measurable ejecta fields to quantitatively investigate in this study. Impact Crater 1 (HiRISE image PSP_008011_1975) is located in the Tharsis region at 17.41°N, 248.75°E and is 175 m in diameter. Impact Crater 2 (HiRISE image ESP_018352_1805) is located in Elysium Planitia at 0.51°N, 163.14°E and is 320 m in diameter. Our block measurements, used to determine the area, were conducted using HiView. Employing methods similar to Krishna and Kumar (2016), we compared block size and axis ratio to block distance from the center of the crater, impact angle, and direction. Preliminary analysis of sixteen radial sectors around Impact Crater 1 revealed that in sectors containing mostly small blocks (less than 10 m2), the small blocks were ejected up to three times the diameter of the crater from the center of the crater. These small block-dominated sectors lacked blocks larger than 10 m2. Contrastingly, in large block-dominated sectors (larger than 30 m2) blocks rarely traveled farther than 200 m from the center of the crater. We also seek to determine the impact angle and direction. Krishna and Kumar (2016) calculate the b-value (N(a) = Ca-b; "N(a) equals the number of fragments or craters with a size greater than a, C is a constant, and -b is a power index") as a method to determine the impact direction. Our preliminary results for Impact Crater 1 did not clearly indicate the impact angle. With improved measurements and the assessment of Impact Crater 2, we will compare Impact Crater 1 to Impact Crater 2 as well as assess the impact angle and direction in order to determine if the craters are secondary craters. Hood, D. and Karunatillake, S. (2017), LPSC, Abstract #2640 Krishna, N., and P. S. Kumar (2016), Icarus, 264, 274-299

Valleys and Ridges at the Deuteronilus Contact in Isidis Planitia, Mars: Implications for an Isidis Sea

NASA Astrophysics Data System (ADS)

Erkeling, G.; Reiss, D.; Hiesinger, H.; Ivanov, M. A.; Bernhardt, H.

2013-09-01

Numerous small valleys are incised into the plains of the southern Isidis basin rim between 82°/90°E and 3°/6°N and trend tens of kilometers to the north following the topographic gradient toward the center of Isidis Planitia. The valleys originate exclusively north of the Libya Montes highlands (Fig. 1) [e.g., 1-4] and are indicative of Late Hesperian fluvial activity [1,4,6], which was spatially and temporarily distinct from intense and repeated Noachian fluvial activity in the Libya Montes [1-4,6]. The majority of the valleys terminate on the smooth Isidis exterior plains (hereafter IEP; Fig. 1). A few of them continue across the boundary between the IEP and the knobby Isidis interior plains (hereafter IIP; Fig. 1) and occur as sinuous ridges in the IIP. This boundary has been discussed as a part of the Deuteronilus contact [e.g., 7,8] and is characterised by an onlap of the IIP onto the IEP, i.e., the IIP are superposed on the IEP. Therefore, the ridges occur stratigraphically higher than the valleys. Because the valleys transition to ridges into less-eroded terrain, their formation is difficult to explain by scenarios based on relief inversion proposed for sinuous ridges on Mars [e.g., 9-11] and Earth [e.g., 12,13]. Based on our investigations we propose an alternative fluvio-glacial formation scenario for the morphologic-geologic setting at the Deuteronilus contact. We suggest that the ridges could be glacial meltwater or subglacial streams (eskers) similar to possible eskers identified elsewhere on Mars and Earth [e.g., 14-17] and that their formation is associated with a stationary ice sheet of a proposed Late Hesperian Isidis Sea that readily froze and sublimated and resulted in the formation of the IIP [4,6]. The proposed formation scenario has also implications for the formation of the Isidis thumbprint terrain (hereafter TPT) [e.g., 5,6] that is located in the IIP.

Utopia e Educacao no Renascimento (Utopia and Education in the Renaissance).

ERIC Educational Resources Information Center

da Silva, Joao Carlos

2000-01-01

Discusses education in utopian ideas of the Renaissance, privileging Thomas More's "Utopia," Tommaso Campanella's "City of the Sun," and Francis Bacon's "Nova Atlantis." Analyzes the importance Renaissance utopian thinkers had in the process of the construction of modern educational thinking, explaining how these…

Mars Global Surveyor Approach Image

NASA Technical Reports Server (NTRS)

1997-01-01

This image is the first view of Mars taken by the Mars Global Surveyor Orbiter Camera (MOC). It was acquired the afternoon of July 2, 1997 when the MGS spacecraft was 17.2 million kilometers (10.7 million miles) and 72 days from encounter. At this distance, the MOC's resolution is about 64 km per picture element, and the 6800 km (4200 mile) diameter planet is 105 pixels across. The observation was designed to show the Mars Pathfinder landing site at 19.4 N, 33.1 W approximately 48 hours prior to landing. The image shows the north polar cap of Mars at the top of the image, the dark feature Acidalia Planitia in the center with the brighter Chryse plain immediately beneath it, and the highland areas along the Martian equator including the canyons of the Valles Marineris (which are bright in this image owing to atmospheric dust). The dark features Terra Meridiani and Terra Sabaea can be seen at the 4 o`clock position, and the south polar hood (atmospheric fog and hazes) can be seen at the bottom of the image. Launched on November 7, 1996, Mars Global Surveyor will enter Mars orbit on Thursday, September 11 shortly after 6:00 PM PDT. After Mars Orbit Insertion, the spacecraft will use atmospheric drag to reduce the size of its orbit, achieving a circular orbit only 400 km (248 mi) above the surface in early March 1998, when mapping operations will begin.

The Mars Global Surveyor is operated by the Mars Surveyor Operations Project managed for NASA by the Jet Propulsion Laboratory, Pasadena CA. The Mars Orbiter Camera is a duplicate of one of the six instruments originally developed for the Mars Observer mission. It was built and is operated under contract to JPL by an industry/university team led by Malin Space Science Systems, San Diego, CA.

Utopia and Education in Critical Theory

ERIC Educational Resources Information Center

Lewis, Tyson

2006-01-01

In this article the author examines the intimate connections between utopia and education in Frankfurt School critical theory. Although substantial links have been made in the critical pedagogy tradition between education, critique, and utopian dreaming, an in-depth analysis of the utopia-education matrix in the works of Herbert Marcuse, Theodor…

The Evolution of Gully Features in Acidalia Planitia

NASA Image and Video Library

2017-10-23

This observation image from NASA's Mars Reconnaisance Orbiter (MRO) captures details regarding the evolution of gully features observed in a crater in Acidalia Planitia. A Context Camera image provides context for these gullies showing an approximately 7-kilometer diameter crater in which we see that the gullies occur exclusively on the northern wall. This is unlike most of the observed gully sites in the northern Martian hemisphere, which typically have gullies on their pole-facing slopes. Another unique observation of this set of gullies is that they start mid-way down the crater's wall rather than cutting directly into the upper crater wall or rim. The younger, more recently active fans are generally rougher than the older, smoother fans that are located near the base of the slope. Consistent with this interpretation, are a number of observed superposition and cross-cutting relationships. The rougher fans are always superimposed over the older, smoother ones. Discontinuous fractures are observed to cross-cut only older features, while the most recently active portions of the gullies, in this case the channels or fans, are not cut by the fractures, but in some cases even superimpose them. This suggests that the fractures formed prior to the last phase of gully activity. https://photojournal.jpl.nasa.gov/catalog/PIA22054

Planetary Geology and Geophysics Program

NASA Technical Reports Server (NTRS)

McGill, George E.

2004-01-01

Geological mapping and topical studies, primarily in the southern Acidalia Planitia/Cydonia Mensae region of Mars is presented. The overall objective was to understand geologic processes and crustal history in the northern lowland in order to assess the probability that an ocean once existed in this region. The major deliverable is a block of 6 1:500,000 scale geologic maps that will be published in 2004 as a single map at 1:1,000,000 scale along with extensive descriptive and interpretive text. A major issue addressed by the mapping was the relative ages of the extensive plains of Acidalia Planitia and the knobs and mesas of Cydonia Mensae. The mapping results clearly favor a younger age for the plains. Topical studies included a preliminary analysis of the very abundant small domes and cones to assess the possibility that their origins could be determined by detailed mapping and remote-sensing analysis. We also tested the validity of putative shorelines by using GIs to co-register full-resolution MOLA altimetry data and Viking images with these shorelines plotted on them. Of the 3 proposed shorelines in this area, one is probably valid, one is definitely not valid, and the third is apparently 2 shorelines closely spaced in elevation. Publications supported entirely or in part by this grant are included.

Morphology and Evolution of Sublimation Pits on Pluto

NASA Astrophysics Data System (ADS)

Abu-Hashmeh, N.; Conrad, J. W.; Nimmo, F.; Moore, J. M.; Stern, A.; Olkin, C.; Weaver, H. A., Jr.; Ennico Smith, K.; Young, L. A.

2017-12-01

Pluto's Sputnik Planitia region hosts a geologically young surface of nitrogen ice that exhibits striking pitted terrain (Moore et al., Science 351, 2016). These pits are most likely formed by sublimation due to incident sunlight, similar to the southern polar cap of Mars (Byrne and Ingersoll, Science 299, 2003); however, their evolution over time has resulted in unique morphological characteristics. Motivated by this, we used the high-resolution mosaic strips captured by New Horizons' Long Range Reconnaissance Imager (LORRI) to map sublimation pits in the southernmost region of Sputnik Planitia. Statistical data shows pit orientations appearing North-South dominant; their morphology also indicates extensional evolution along the major axis caused by further sublimation and contact-coalescence processes. Qualitative analysis of the region yielded indications of an evolutionary path for individual pits that coalesce into each other and exhibit an elongated end-stage. Additionally, densely-pitted regions generally appear to correlate with regions containing longer pits, implying that coalescence may be an important process for elongation. We also model the evolution geometry through competing effects of diffusion (viscous relaxation) and retreat (sublimation) (Buhler and Ingersoll, LPSC Abstract #1746, 2017). The model demonstrates single-pit and coalescing-pit evolutions that influence overall length, as well as a potential ability for the pit center to move in space while the pit morphology evolves.

Crustal Evolution of the Protonilus Mensae Area, Mars

NASA Technical Reports Server (NTRS)

McGill, G. E.; Smrekar, S. E.; Dimitriou, A. M.; Raymond, C. A.

2004-01-01

Despite research by numerous geologists and geo- physicists, the age and origin of the martian crustal dichotomy remain uncertain. Models for the origin of this dichotomy involve single or multiple impact, mantle megaplumes, primordial crustal asymmetry, and plate tectonics. Most of these models imply a Noachian age for the dichotomy. A major problem common to all genetic models is the difficulty separating the features resulting from the primary cause for the dichotomy from features due to younger fault- ing, impact cratering, volcanism, deposition, and erosion. highlands (the dichotomy boundary) approximates a small circle that ranges in latitude from about -10 deg. in Elysium Planitia to about +45 deg. north of Arabia Terra. For much of its length the boundary is characterized by relatively steep scarps separating highland plateau to the south from lowland plains to the north, generally with a complex transition zone on the lowland side of these scarps. These scarps are almost certainly due to normal faulting. The type fretted terrain, which defines the boundary in north-central Arabia Terra, also is characterized by scarps but has under- gone a more complex history of faulting and dissection [13]. In some places, notably in the Acidalia Planitia region, the dichotomy boundary is gradational. In the Tharsis region the boundary is obscured by younger volcanics.

Effect of Cover Thickness on the Relationship of Surface Relief to Diameter of Northern Lowland QCDs on Mars

NASA Technical Reports Server (NTRS)

Buczkowski, D. L.; Frey, H. V.; McGill, G. E.

2005-01-01

Previous work has established that there is a relationship of surface relief to diameter for quasi-circular depressions (QCDs) around the Utopia Basin [1]. This relationship has been used to support the contention that the QCDs represent impact craters buried beneath a differentially compacting cover material. For any given regional cover thickness, total cover thickness is greater over the centers of completely buried craters than over their rims; thus total compaction is greater over the center of craters than their rims and topographic depressions will form. Since large craters are deeper than small craters, differential compaction models also predict that surface relief will be proportional to the diameter of the buried crater [2]. It is highly unlikely, however, that the material covering the QCD impact craters is a consistent thickness throughout the entire northern lowlands of Mars. We explore the effects that changes in cover thickness would have on the surface relief vs. diameter relationship of QCDs.

Family Roles in America's Utopian Communities from the 1820s to the 1920s.

ERIC Educational Resources Information Center

Hewes, Dorothy W.

This review of the literature about fictional and actual utopian communities focuses on parents and children in American utopias. Introductory comments explore the history and defining characteristics of utopias. The next section highlights references to women, children, education, and parenting in several fictional utopias, including Plato's…

Aeolian Sediment Transport Pathways and Aerodynamics at Troughs on Mars

NASA Technical Reports Server (NTRS)

Bourke, Mary C.; Bullard, Joanna E.; Barnouin-Jha, Olivier S.

2004-01-01

Interaction between wind regimes and topography can give rise to complex suites of aeolian landforms. This paper considers aeolian sediment associated wit11 troughs on Mars and identifies a wider range of deposit types than has previously been documented. These include wind streaks, falling dunes, "lateral" dunes, barchan dunes, linear dunes, transverse ridges, sand ramps, climbing dunes, sand streamers, and sand patches. The sediment incorporated into these deposits is supplied by wind streaks and ambient Planitia sources as well as originating within the trough itself, notably from the trough walls and floor. There is also transmission of sediment between dneTsh. e flow dynamics which account for the distribution of aeolian sediment have been modeled using two-dimensional computational fluid dynamics. The model predicts flow separation on the upwind side of the trough followed by reattachment and acceleration at the downwind margin. The inferred patterns of sediment transport compare well with the distribution of aeolian forms. Model data indicate an increase of wind velocity by approx. 30 % at the downwind trough margin. This suggests that the threshold wind speed necessary for sand mobilization on Mars will be more freqentmlye t in these inclined locations.

Evidence for an Ancient Buried Landscape on the NW Rim of Hellas Basin, Mars

NASA Technical Reports Server (NTRS)

Crown, David A.; Bleamaster, Leslie F., III; Mest, Scott C.; Mustard, John F.; Vincendon, Mathieu

2010-01-01

Hellas basin is the largest (2000+ km across) well-preserved impact structure on Mars and its deepest depositional sink [e.g., 1]. The Hellas rim and adjacent highlands are of special interest given the possibility of paleolakes on the basin floor [2-4], recent studies of potential localized fluvial/lacustrine systems [2, 5-17], and evidence for phyllosilicates around and within impact craters north of the basin [18-26]. We are producing a 1:1.5M-scale geologic map of eight MTM quadrangles (-25312, -25307, -25302, -25297, -30312, -30307, -30302, -30297) along Hellas NW rim. The map region (22.5-32.5degS, 45- 65degE) includes a transect across the cratered highlands of Terra Sabaea, the degraded NW rim of Hellas, and basin interior deposits of NW Hellas Planitia. No previous mapping studies have focused on this region, although it has been included in earlier global and regional maps [27-29].

Map of Martian Potassium at Mid-Latitudes

NASA Image and Video Library

2003-03-13

This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element potassium. Potassium, having the chemical symbol K, is a naturally radioactive element and is a minor constituent of rocks on the surface of both Mars and Earth. The region of highest potassium content, shown in red, is concentrated in the northern part of Acidalia Planitia (centered near 55 degrees N, -30 degrees). Several areas of low potassium content, shown in blue, are distributed across the mid-latitudes, with two significant low concentrations, one associated with the Hellas Basin (centered near 35 degrees S, 70 degrees) and the other lying southeast of Elysium Mons (centered near 10 degrees N, 160 degrees). Contours of constant surface elevation are also shown. The long continuous line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south. http://photojournal.jpl.nasa.gov/catalog/PIA04255

Dystopian Schools: Recovering Dewey's Radical Aesthetics in an Age of Utopia-Gone-Wrong

ERIC Educational Resources Information Center

Heybach, Jessica A.; Sheffield, Eric C.

2014-01-01

In this article, we first suggest that contemporary school policies and practices represent a utopia-gone-wrong. In striving for an unattainable educational utopia--that is, all students will be proficient in math and reading by 2014--current polices and their resulting practices have brought a classic dystopian turn--the dehumanization of…

Geologic mapping of Argyre Planitia

NASA Technical Reports Server (NTRS)

Gorsline, Donn S.; Parker, Timothy J.

1995-01-01

This report describes the results from the geologic mapping of the central and southern Argyre basin of Mars. At the Mars Geologic Mapper's Meeting in Flagstaff during July, 1993, Dave Scott (United States Geological Survey, Mars Geologic Mapping Steering Committee Chair) recommended that all four quadrangles be combined into a single 1:1,000,000 scale map for publication. It was agreed that this would be cost-effective and that the decrease in scale would not compromise the original science goals of the mapping. Tim Parker completed mapping on the 1:500,000 scale base maps, for which all the necessary materials had already been produced, and included the work as a chapter in his dissertation, which was completed in the fall of 1994. Geologic mapping of the two southernmost quadrangles (MTM -55036 and MTM -55043; MTM=Mars Transverse Mercator) was completed as planned during the first year of work. These maps and a detailed draft of the map text were given a preliminary review by Dave Scott during summer, 1993. Geologic mapping of the remaining two quadrangles (MTM -50036 and MTM -50043) was completed by summer, 1994. Results were described at the Mars Geologic Mappers Meeting, held in Pocatello, Idaho, during July, 1994. Funds for the third and final year of the project have been transferred to the Jet Propulsion Laboratory, where Tim Parker will revise and finalize all maps and map text for publication by the United States Geological Survey at the 1:1,000,000 map scale.

Geology and MER target site characteristics along the southern rim of Isidis Planitia, Mars

USGS Publications Warehouse

Crumpler, L.S.; Tanaka, K.L.

2003-01-01

The southern rim of the Isidis basin contains one of the highest densities of valley networks, several restricted paleolake basins, and the stratigraphically lowest (oldest) terrain on Mars. Geologic mapping in Viking, MGS/MOC, and MOLA data, Odyssey/ THEMIS data, and other multispectral data products supports the presence of extensive fans of debris and sediments deposited along the inner rim of the Isidis basin where large valleys enter the lowlands. Additional processes subsequent to the period of intense fluvial activity, including mass flow analogous to some glacial processes, have contributed to the materials accumulated on the margins of the Isidis basin. These have occurred along preexisting channels and valleys at the termini of major channels where they enter the plains along the highland-lowland boundary. If the abundant valley networks in highland terrains are the result of runoff accompanied by saturated groundwater flow, as has been suggested in previous studies of ancient fluvial highland terrains, then the extreme age and abundance of early valley networks in the Libya Montes highland rocks should have resulted in deposition of materials that record evidence for the long-term presence of water in the form of aqueous alteration of polycrystalline constituents. The material deposited along the basin margin is likely to consist of ancient altered highland rocks in several physical states (weathered, rounded, and angular) exposing both weathered and altered surfaces, and exposures of alteration profiles in fractured faces and unweathered material from rock interiors. Debris fans shed off the southern rim of Isidis Planitia should contain materials that have experienced possible saturated groundwater flow, residence within paleolake basins, and derivative materials deposited during the most fluvially intensive part of Martian geologic history. Many of these materials have also been reworked by ice-related processes. In situ measurements of the ancient crustal materials, in the form of rocks within the debris fans, and the weathered condition of the rocky material are potential sources for mineralogical evidence of climatic conditions in earliest Martian geologic history. The absence of alteration within rocks would, on the other hand, support the hypothesis that fluvial runoff during the earliest history of Mars was geologically brief rather than long-term and that long-term saturated groundwater flow was not present. Determination of the presence or absence of alteration would have corresponding implications for hypotheses requiring the long-term presence of aqueous solutions (i.e., complex organic compounds and life). A proposed MER site along the margin addresses realistic field science objectives of the Mars Exploration Rover mission and the current goals of the Mars Exploration Program. In situ measurements may be important in deriving estimates of the longevity and intensity of past wetter climates. Copyright 2003 by the American Geophysical Union.

Mars: the evolutionary history of the northern lowlands based on crater counting and geologic mapping

USGS Publications Warehouse

Werner, S.C.; Tanaka, K.L.; Skinner, J.A.

2011-01-01

The geologic history of planetary surfaces is most effectively determined by joining geologic mapping and crater counting which provides an iterative, qualitative and quantitative method for defining relative ages and absolute model ages. Based on this approach, we present spatial and temporal details regarding the evolution of the Martian northern plains and surrounding regions. The highland–lowland boundary (HLB) formed during the pre-Noachian and was subsequently modified through various processes. The Nepenthes Mensae unit along the northern margins of the cratered highlands, was formed by HLB scarp-erosion, deposition of sedimentary and volcanic materials, and dissection by surface runoff between 3.81 and 3.65 Ga. Ages for giant polygons in Utopia and Acidalia Planitiae are ~ 3.75 Ga and likely reflect the age of buried basement rocks. These buried lowland surfaces are comparable in age to those located closer to the HLB, where a much thinner, post-HLB deposit is mapped. The emplacement of the most extensive lowland surfaces ended between 3.75 and 3.4 Ga, based on densities of craters generally View the MathML source> 3 km in diameter. Results from the polygonal terrain support the existence of a major lowland depocenter shortly after the pre-Noachian formation of the northern lowlands. In general, northern plains surfaces show gradually younger ages at lower elevations, consistent local to regional unit emplacement and resurfacing between 3.6 and 2.6 Ga. Elevation levels and morphology are not necessarily related, and variations in ages within the mapped units are found, especially in units formed and modified by multiple geological processes. Regardless, most of the youngest units in the northern lowlands are considered to be lavas, polar ice, or thick mantle deposits, arguing against the ocean theory during the Amazonian Period (younger than about 3.15 Ga). All ages measured in the closest vicinity of the steep dichotomy escarpment are also 3.7 Ga or older. The formation ages of volcanic flanks at the HLB (e.g., Alba Mons (3.6–3.4 Ga) and the last fan at Apollinaris Mons, 3.71 Ga) may give additional temporal constraint for the possible existence of any kind of Martian ocean before about 3.7 Ga. It seems to reflect the termination of a large-scale, precipitation-based hydrological cycle and major geologic processes related to such cycling.

The Ares 3 Landing Site: Where Science Fact Meets Fiction

NASA Image and Video Library

2015-10-05

This image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter shows a location on Mars associated with the best-selling novel and Hollywood movie, "The Martian." This area is in the Acidalia Planitia region. In the novel and the movie, it is the landing site of a crewed mission named Ares 3. For the story's central character, Acidalia Planitia is within driving distance from where NASA's Mars Pathfinder, with its Sojourner rover, landed in 1997. An initial HiRISE image of the site was taken in April 2015 and is online at http://hirise.lpl.arizona.edu/ESP_040776_2115. A second one was taken May 17, 2015, and is shown here. Figure 1 is a stereo combination of the two, appearing three-dimensional when viewed through blue-red glasses with the red lens on the left One of the main objectives of the HiRISE camera is to carry out "monitoring science", which involves taking images of certain areas of high scientific interest on regular intervals. The team usually does so to monitor a seasonal or recurring process such as seasonal changes in carbon-dioxide ice near the poles, dune movement or recurring flow-like features on some slopes. HiRISE also takes repeated images of areas with active rovers, such as Curiosity, to help plan safe routes toward areas of high scientific interest. Another key responsibility for the HiRISE camera is to provide information for use in selection of landing sites for future missions. One technique is to image a site of interest at least twice when the weather conditions are similar, but with a small difference in viewing angle, much like what you would experience if you looked at something with only your right eye, then looked at it again with the left. By doing this, we are able to build a stereo view of the site, providing a chance to identify high and low points in the site more effectively. This resulting 3-D information can combined with elevation data from laser altimeters to create a highly accurate "digital terrain model" or DTM for short. DTMs allow researchers to view the locations in 3-D and to analyze them by measuring the exact height of features that could be hazardous to the future mission, such as large boulders or small impact craters. DTMs from HiRISE were a key factor in choosing the landing site for NASA's Curiosity Mars rover in Gale Crater and are being used to evaluate sites under consideration for the NASA's 2016 InSight Mars lander and Mars 2020 rover missions. The location of the site in this image is 31.3 degrees north latitude, 331.3 degrees east latitude. The image is an excerpt from HiRISE observation ESP_041277_2115. http://photojournal.jpl.nasa.gov/catalog/PIA19913

Southern rim of Isidis Planitia basin

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 11 April 2002) The Science This image, crossing the southern rim of the Isidis Planitia basin, displays the contrasting morphologies of the relatively rough highland terrain (in the lower portion of the image) and the relatively smooth materials of the basin (at top). Upon closer viewing, the basin materials display an extensive record of cratering, including a small cluster of craters just north and west of the two prominent craters in the upper part of the image. This cluster of craters may represent what are called 'secondary' craters, which are craters that form as a result of the ejection of debris from a nearby impact. Alternatively, these craters may have formed simultaneously by the impact of many pieces of a larger meteoroid that broke up upon entry into Mars' atmosphere. The large craters in the image are approximately 800 meters (875 yards) in diameter. Also visible in the image are dark streaks on the east-facing side of the north-south trending ridge. These streaks are likely the result of debris movement down slope. A dark patch of material is visible at the left of the image; dark materials are typically mobile sands, and linear dune forms are apparent within the dark patch. The Story Battered and beaten up, the surface of Mars reads like a history book to geologists, who want to study what has happened to the red planet over its geological history. Look for two larger craters diagonal from one another in the northern part of this image, and then for the smattering of tinier craters near them. How did these smaller craters come to be? Did a large meteoroid streak in through the Martian atmosphere and get broken up as it passed through, pummeling Mars moments later with its smaller, scattered pieces? Or were rocks and dirt blasted off the surface when the two larger craters were formed, only to rain down again on Mars shortly afterwards? No one quite knows for sure.... Another enigmatic-looking feature is near the left center of this image. Dark and shadowy-seeming, it looks something like an exclamation point with the small crater just below it. Look closely, and you'll see dunes within the large, dark, blurry patch, which is itself probably composed of moving sands. Dark, streaky features also appear on the eastern side of the ridge that runs down the right side of the image, showing how debris once tumbled down its steepened slopes.

Utopia: An Imaginative, Critical and Playful Dialogue on the Meaning and Practice of Contemporary Education

ERIC Educational Resources Information Center

Hayes, Michael T.; Marino, Matthew

2015-01-01

In this article the authors re-examine Sir Thomas More's classic book "Utopia" as a potential source of ideas and concepts for examining, understanding and imagining contemporary education. Too often the concept utopia is used to criticize an idea, perspective or image as offering a simplistic solution to a complex problem, or, at its…

Geologic Map of the Niobe Planitia Quadrangle (V-23), Venus

USGS Publications Warehouse

Hansen, Vicki L.

2009-01-01

The Niobe Planitia quadrangle (V-23) encompasses approximately 8,000,000 km2 of the Venusian equatorial region extending from lat 0 deg to 25 deg N. and from long 90 deg to 120 deg E. (approximately 9,500 15-minute quadrangles on Earth). The map area lies along the north margin of the equatorial highland, Aphrodite Terra (V-35), and extends into the lowland region to the north, preserving a transition from southern highlands to northern lowlands (figs. 1, 2, map sheet). The northern parts of the crustal plateau, Ovda Regio and Haasttse-baad Tessera, mark the south margin of the map area; Niobe and Sogolon Planitiae make up the lowland region. The division between Niobe and Sogolon Planitiae is generally topographic, and Sogolon Planitia forms a relatively small elongate basin. Mesolands, the intermediate topographic level of Venus, are essentially absent or represented only by Gegute Tessera, which forms a slightly elevated region that separates Niobe Planitia from Llorona Planitia to the east (V-24). Lowlands within the map area host five features currently classified as coronae: Maya Corona (lat 23 deg N., long 97 deg E.) resides to the northwest and Dhisana, Allatu, Omeciuatl, and Bhumiya Coronae cluster loosely in the east-central area. Lowlands extend north, east, and west of the map area. Mapping the Niobe Planitia quadrangle (V-23) provides an excellent opportunity to examine a large tract of lowlands and the adjacent highlands with the express goal of clarifying the processes responsible for resurfacing this part of Venus and the resulting implications for Venus evolution. Although Venus lowlands are widely considered to have a volcanic origin, lowlands in the map area lack adjacent coronae or other obvious volcanic sources.

Four Views of Mars in Northern Summer

NASA Technical Reports Server (NTRS)

1997-01-01

Four faces of Mars as seen on March 30, 1997 are presented in this montage of NASA Hubble Space Telescope images. Proceeding in the order upper-left, upper-right, lower-left, lower-right, Mars has rotated about ninety degrees between each successive time step. For example the Tharsis volcanoes, which are seen (between 7:30 and 9 o'clock positions) in mid-morning in the UPPER-RIGHT view, are seen near the late afternoon edge of the planet (about 3 o'clock position) in the lower-left image. All of these color images are composed of individual red (673 nanometers), green (502 nm), and blue (410 nm) Planetary Camera exposures.

Upper left: This view is centered on Ares Valles, where Pathfinder will land on July 4, 1997; the Valles Marineris canyon system stretches to the west across the lower left portion of the planet, while the bright, orangish desert of Arabia Planitia is to the east. The bright polar water-ice cap, surrounded by a dark ring of sand dunes, is obvious in the north; since it is northern summer and the pole is tilted toward us, the residual north polar cap is seen in its entirety in all four images. Acidalia Planitia, the prominent dark area fanning southward from the polar region, is thought to have a surface covered with dark sand. Numerous 'dark wind streaks' are visible to the south of Acidalia, resulting from wind-blown sand streaming out of the interiors of craters.

Upper right: The Tharsis volcanos and associated clouds are prominent in the western half of this view. Olympus Mons, spanning 340 miles (550 km) across its base and reaching an elevation of 16 miles (25 km), extends through the cloud deck near the western limb, while (from the south) Arsia Mons, Pavonis Mons, and Ascraeus Mons are to the west of center. Valles Marineris stretches to the east, and the Pathfinder landing site is shrouded in clouds near the afternoon limb.

Lower left: This relatively featureless sector of Mars stretches from the Elysium volcanic region in the west to the Tharsis volcanoes (shrouded by the bright clouds near the afternoon limb) in the east. The group of three dark specks just left of center are all that remain of Cerberus, a very prominent dark region during the Viking and Mariner 9 missions. This is an example of the remarkable large scale changes which can occur on Mars due to windblown dust: the former dark area has now been covered by a layer of bright dust, masking the underlying material.

Lower right: The dark Syrtis Major region dominates this image. Syrtis Major is one of the most prominent dark features on Mars, and has been visible since ground-based observers first peered at Mars through telescopes. The bright cloud at 3 o'clock is associated with Elysium Mons. The bright bluish-white feature near the southern limb of the planet is Hellas, a 1,200 mile (2,000 km) diameter impact basin formed by the collision of a large body with Mars long ago. Hellas is covered with dry ice frost and clouds during this season (winter in the south).

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

Shallow structure of the InSight 2018 landing site in Elysium Planitia, Mars, from ambient vibration Rayleigh wave ellipticity: A modeling study

NASA Astrophysics Data System (ADS)

Knapmeyer-Endrun, B.; Golombek, M.; Ohrnberger, M. M.

2016-12-01

The SEIS (Seismic Experiment for Interior Structure) instrument onboard NASA's InSight mission, scheduled to land in November 2018, will be the first seismometer directly deployed on the surface of Mars. From studies on both the Earth and the Moon, it is well known that site amplification in low-velocity sediments, e.g. regolith, on top of more competent rocks has a strong influence on seismic signals, but can also be used to constrain the subsurface structure. Based on orbital data, lab measurements and terrestrial analogues, we construct a model of the shallow sub-surface at the landing site in western Elysium Planitia and simulate the ambient vibration wavefield. We show how Rayleigh wave ellipticity can be extracted from these data and inverted for shallow structure. Using reasonable variations in regolith properties, we do not expect any influence of site resonances on teleseismic quakes recorded by InSight, but recordings of local events will likely be affected. We find that higher mode ellipticity information might be extracted from the data, significantly reducing uncertainties in the inversion. Though the data are most sensitive to properties of the upper-most layer and show a strong trade-off between layer depth and velocity, it is possible to estimate the velocity and thickness of the sub-regolith layer and distinguish between different models by using reasonable constraints on regolith properties. Model parameters are best constrained if either higher mode data can be used or additional constraints on regolith properties, e.g. from analysis of hammer strokes of the HP3 heat flow probe or orbital mapping of regolith thickness from the onset diameter of rocky ejecta craters, are available. In addition, Rayleigh wave ellipticity can differentiate between models with a constant regolith velocity and models with increasing velocity with depth. We also discuss the influence of lander and leveling system mechanical noise on the identification of site resonances.

Meter-scale slopes of candidate MER landing sites from point photoclinometry

USGS Publications Warehouse

Beyer, R.A.; McEwen, A.S.; Kirk, R.L.

2003-01-01

Photoclinometry was used to analyze the small-scale roughness of areas that fall within the proposed Mars Exploration Rover (MER) 2003 landing ellipses. The landing ellipses presented in this study were those in Athabasca Valles, Elysium Planitia, Eos Chasma, Gusev Crater, Isidis Planitia, Melas Chasma, and Meridiani Planum. We were able to constrain surface slopes on length scales comparable to the image resolution (1.5 to 12 m/pixel). The MER 2003 mission has various engineering constraints that each candidate landing ellipse must satisfy. These constraints indicate that the statistical slope values at 5 m baselines are an important criterion. We used our technique to constrain maximum surface slopes across large swaths of each image, and built up slope statistics for the images in each landing ellipse. We are confident that all MER 2003 landing site ellipses in this study, with the exception of the Melas Chasma ellipse, are within the small-scale roughness constraints. Our results have provided input into the landing hazard assessment process. In addition to evaluating the safety of the landing sites, our mapping of small-scale roughnesses can also be used to better define and map morphologic units. The morphology of a surface is characterized by the slope distribution and magnitude of slopes. In looking at how slopes are distributed, we can better define landforms and determine the boundaries of morphologic units. Copyright 2003 by the American Geophysical Union.

Geologic history of the Cerberus Plains, Mars

NASA Astrophysics Data System (ADS)

Lanagan, Peter Denham

This work examines the relative chronology of geologic units within the Cerberus Plains of Mars with an emphasis on lava flows emplaced after the last Marte Valles fluvial episode. High resolution images show the bulk of the Cerberus Plains is covered by platy-ridged and inflated lavas, which are interpreted as insulated sheet flows. Eastern Cerberus Plains lavas originate at Cerberus Fossae fissures and shields. Some flows extend for >2000 km through Marte Valles into Amazonis Planitia. Athabasca Valles are both incised into pristine lavas and embayed by pristine lavas, indicating that Athabascan fluvial events were contemporaneous with volcanic eruptions. Deposits of the Medusae Fossae Formation lie both over and under lavas, suggesting the deposition of the Medusae Fossae Formation was contemporaneous with volcanism. Statistics of small craters indicate lavas in the Western Cerberus Plains may be less than a million years old, but the model isochrons may be unreliable if the small crater population is dominated by secondary craters. Images showing no large craters with diameters >500 m superimposed on Western Cerberus Plains lavas indicate the same surface is younger than 49 Ma. High resolution Mars Orbiter Camera (MOC) images have revealed the existence of small cones in the Cerberus Plains, Marte Valles, and Amazonis Planitia. These cones are similar in both morphology and planar dimensions to the larger Icelandic rootless cones, which form due to explosive interactions between surficial lavas and near-surface groundwater. If martian cones form in the same manner as terrestrial rootless cones, then equatorial ground-ice or ground water must have been present near the surface in geologically recent times. Evidence for a shallow lake in the Western Cerberus Plains during the Late Amazonian is also presented. High-resolution images show features interpreted as flood-eroded scarps and fluvial spillways exiting the lake. Based on present-day topography, a lake would have covered an area of 8.4 x 10 4 km 2 , had an average depth of 12 m, and have contained a volume of 1.0 x 10 3 km 3 of water. Lake waters were likely primarily lost to the atmosphere through sublimation, although some quantity of water likely spilled into the Eastern Cerberus Plains or infiltrated into the shallow crust.

Cratered cones in Southern Cerberus Palus, Mars: Evidence for phreatovolcanism associated with interactions between Amazonian aged lavas and the Medusae Fossae Formation

NASA Astrophysics Data System (ADS)

Stacey, K.; Kerber, L.

2017-12-01

Abundant cratered cones have been identified in Southern Cerberus Palus where young, Cerberus Fossae-derived lavas interact with Medusae Fossae Formation (MFF) materials from Aeolis Planum and Zephyria Planum. These regions contain cones analogous to Icelandic pseudocraters, but the cones display characteristics that differentiate them from others that have been previously described elsewhere on Mars. The cones in this study are found abutting the MFF border, where yardang fleets are embayed by Cerberus lavas, and within flood lavas that overlie MFF deposits west of Zephyria Planum. Rootless cones have formerly been observed in areas of Athabasca Valles, Amazonis Planitia, Elysium Planitia, and Marte Valles. Using HiRISE and CTX imagery from the Mars Reconnaissance Orbiter, Southern Cerberus Palus cones are observed to preferentially form along the tops of partially and fully embayed yardangs. In addition, the cones often form in circular groups atop impact crater rims, and occasionally have large cracks along their flanks. Some cones are also found in linear chains along fissures of obscured origins. Several of these attributes have been noted in previous studies of Martian cratered cones and interpreted as a result of unusual contact geometries with the substrate and a tendency to form at topographic highs, where overburden pressures are minimal (Jaeger et al 2007). Surrounding many cones are areas of light colored, smooth material with lobate margins, below the level of the neighboring rubbly lava. The surface texture of this material is similar to the smooth, polygonally fractured material often found in rifts between Cerberus lava plates, but do not appear to result from tearing in the surrounding lava surface, as they have no preferred size or direction. Due to their overall morphology and distribution, the cones in this study are interpreted to most likely be rootless, hydrovolcanic features formed by explosive interactions between lava flows and H2O present in MFF substrate. The form and quantity of this water is currently unknown; possible hypotheses include sequences of ice deposits, interstitial regolith ice, or possibly hydrated minerals. Spatial distributions of the cones indicate that the conditions required for their formation are not present everywhere the MFF encounters the Cerberus flows.

Getting Under Mars' Skin: The InSight Mission to the Deep Interior of Mars

NASA Astrophysics Data System (ADS)

Banerdt, W. B.; Asmar, S.; Banfield, D. J.; Christensen, U. R.; Clinton, J. F.; Dehant, V. M. A.; Folkner, W. M.; Garcia, R.; Giardini, D.; Golombek, M. P.; Grott, M.; Hudson, T.; Johnson, C. L.; Kargl, G.; Knapmeyer-Endrun, B.; Kobayashi, N.; Lognonne, P. H.; Maki, J.; Mimoun, D.; Mocquet, A.; Morgan, P.; Panning, M. P.; Pike, W. T.; Spohn, T.; Tromp, J.; Weber, R. C.; Wieczorek, M. A.; Russell, C. T.

2015-12-01

The InSight mission to Mars will launch in March of 2016, landing six months later in Elysium Planitia. In contrast to the 43 previous missions to Mars, which have thoroughly explored its surface features and chemistry, atmosphere, and searched for past or present life, InSight will focus on the deep interior of the planet. InSight will investigate the fundamental processes of terrestrial planet formation and evolution by performing the first comprehensive surface-based geophysical measurements on Mars. It will provide key information on the composition and structure of an Earth-like planet that has gone through most of the evolutionary stages of the Earth up to plate tectonics. The planet Mars can play a key role in understanding early terrestrial planet formation and evolution. Unlike the Earth, its overall structure appears to be relatively unchanged since the first few hundred million years after formation; unlike the Moon, it is large enough that the P-T conditions within the planet span an appreciable fraction of the terrestrial planet range. Thus the large-scale chemical and structural evidence preserved in Mars' interior should tell us a great deal about the processes of planetary differentiation and heat transport. InSight will undertake this investigation using the "traditional" geophysical techniques of seismology, precision tracking (for rotational dynamics), and heat flow measurement. The predominant challenge, in addition to the technical problems of the remote installation and operation of instruments on a distant and harsh planetary surface, comes from the practical limitation of working with data acquired from a single station. We will discuss how we overcome these limitations through the application of single-station seismic analysis techniques, which take advantage of some of the specific attributes of Mars, and global heat flow modeling, which allows the interpretation of a single measurement of a spatially inhomogeneous surface distribution.

Boulder 'Big Joe' And Surface Changes On Mars

NASA Technical Reports Server (NTRS)

1976-01-01

This pair of pictures from Viking Lander 1 at Mars' Chryse Planitia shows the only unequivocal change in the Martian surface seen by either lander. Both images show the one-meter (3-foot) high boulder nicknamed 'Big Joe.' Just to the lower right of the rock (right photo) is a small-scale slump feature. The picture at left shows a smooth, dust-covered slope; in the picture at right the top surface layer can be seen to have slipped downslope. The event occurred sometime between Oct. 4, 1976, and Jan 24, 1977. (Pictures taken before Oct. 4 do not show the slump; the first picture in which it appears was taken Jan. 24.) The surface layer, between one-half and one centimeter (one-fifth to one-third inch) thick, is apparently less cohesive than the underlying material. The layer that slipped formed a 30-centimeter-long (11.8-inch) 'tongue' of soil and a patch of exposed underlying material. The triggering mechanism for the event is unknown, but could have been temperature variations, wind gusts, a seismic event, or perhaps the lander's touchdown on July 20, 1976.

Finalist Site for Next Landing on Mars

NASA Image and Video Library

2015-03-04

This map shows the single area under continuing evaluation as the InSight mission's Mars landing site, as of a year before the mission's May 2016 launch. The finalist ellipse marked within the northern portion of flat-lying Elysium Planitia is centered at about 4.5 degrees north latitude and 136 degrees east longitude. InSight -- an acronym for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport -- will study the interior of Mars to improve understanding of the processes that formed and shaped rocky planets, including Earth. The mission's launch period begins March 4, 2016, and lasts until late March. Whichever day during that period the launch occurs, landing is scheduled for Sept. 28, 2016. The landing ellipse on this map covers an area within which the spacecraft has about 99 percent chance of landing when targeted for the center of the ellipse. It is about 81 miles (130 kilometers) long, generally west to east, and about 17 miles (27 kilometers) wide. This ellipse covers the case of a launch at the start of the launch period. If the launch occurs later in the period, orientation of the landing ellipse would shift slightly clockwise. Four semifinalist sites in Elysium Planitia were evaluated as safe for InSight landing. This one was selected as having the largest proportion of its area classified as smooth terrain. If continuing analysis identifies unexpected problems with this site, another of the semifinalists could be reconsidered before final selection later this year. The InSight lander will deploy two instruments directly onto the ground using a robotic arm. One is a seismometer contributed by France's space agency (CNES) with components from Germany, Switzerland, the United Kingdom and the United States. The seismometer will measure microscopic ground motions, providing detailed information about the interior structure of Mars. The other instrument to be deployed by the arm is a heat-flow probe contributed by the German Aerospace Center (DLR), designed to hammer itself three to five meters (about 10 to 16 feet) deep. It will monitor heat coming from the planet's interior. The mission will also track the lander's radio to measure wobbles in the planet's rotation that relate to the size of its core. A suite of environmental sensors will monitor the weather and variations in the magnetic field. The base map is a mosaic of daytime thermal images from the Thermal Emission Imaging System (THEMIS) on NASA's Mars Odyssey orbiter. THEMIS was developed and is operated by Arizona State University, Tempe. Note: After thorough examination, NASA managers have decided to suspend the planned March 2016 launch of the Interior Exploration using Seismic Investigations Geodesy and Heat Transport (InSight) mission. The decision follows unsuccessful attempts to repair a leak in a section of the prime instrument in the science payload. http://photojournal.jpl.nasa.gov/catalog/PIA19143

A recent, equatorial, periglacial environment on Mars

NASA Astrophysics Data System (ADS)

Balme, M. R.; Gallagher, C.; Murray, J. B.; Muller, J.-P.

2009-04-01

During the Viking era, Mars' recent climatic history was held to be cold and dry with little evidence for long-lived liquid water near the surface; signs of a past wetter, warmer climate were confined to ancient Noachian or Hesperian-aged terrains. Recent missions have revealed contemporary near-surface water-ice to be abundant at high latitudes, and a population of mid-latitude fluvial-like gullies that appear to have formed by transient melting of ice or snow. Thus today's view of Mars' recent surface evolution is one of global permafrost existing within a framework of climate change, the timescales of which are governed by obliquity cycles with periods of tens to hundreds of thousands of years. However, in recent mapping work of the equatorial Elysium Planitia region using the latest very high resolution images of Mars (HiRISE; 25cm/pixel) we have found evidence for longer-lived, geologically recent liquid water at the martian surface. This suggests that there was a recent period when the climate was warmer than current obliquity cycle-based models predict. The Elysium Planitia region of Mars is both geologically young (late Amazonian period; <100 Ma) and hosts a variety of landforms that are morphologically similar to those of periglacial and permafrost environments on Earth. The region was exposed to massive flooding from deep underground sources during the late Amazonian, as demonstrated by the distinctive fluvial morphologies seen in the outflow channel Athabasca Vallis. These floods would have provided both the source of ice and particulate material required for a periglacial or permafrost landscape and there was probably a long-lived, but slowly freezing, lake or sea in the downstream Elysium basin. However, the provenance of the materials and landforms of this region is disputed: many authors still regard the Athabasca Vallis and Elysium basin as being flood lava provinces, with effusive volcanic materials reoccupying earlier flood landscapes (a classic problem of convergent morphology). We present context mapping results of this area and show HiRISE images of periglacial landforms in the region that include sorted stone circles, pingoes and retrogressive scarp erosion. These point to a recent periglacial (i.e. ground ice with temperatures that cycle above the melting point), rather than permafrost (i.e. ground ice in which temperatures are always below the melting point) environment, and thus a recent period in which Mars' climate was warmer (and thus the atmosphere was likely to have been denser) than current models suggest. Interestingly, this proposed warm period might also explain the formation of the aforementioned fluvial-like gullies: perhaps the gullies formed in this warmer, denser atmosphere when ice or snow would melt rather than sublimate, in contrast to the behaviour of ice under today's thin atmosphere? Furthermore, the morphology of the degradational landforms demonstrate that the polygonal patterned grounds seen near the head of the Athabasca Vallis are ground-ice, rather than volcanic, in origin, bringing into doubt the hypothesis that the wider Elysium/Amazonis deposits are flood lavas. The source of the water and ice that was once present here was likely to have been a sub-surface aquifer. Models suggest that liquid water could persist beneath the cryosphere for geologically long time periods. Thus the debris that comprises these deposits represents an exciting target for astrobiological studies and, if engineering constraints can be met, the Elysium/Athabasca region could be considered a prime target for the ExoMars lander.

Geological Evolution of the Ganiki Planitia Quadrangle (V14) on Venus

NASA Technical Reports Server (NTRS)

Grosfils, E. B.; Drury, D. E.; Hurwitz, D. M.; Kastl, B.; Long, s. M.; Richards, J. W.; Venechuk, E. M.

2005-01-01

The Ganiki Planitia quadrangle (25-50degN, 180-210degE) is located north of Atla Regio, south of Vinmara Planitia, and southeast of Atalanta Planitia. The region contains a diverse array of volcanic-, tectonic- and impact-derived features, and the objectives for the ongoing mapping effort are fivefold: 1) explore the formation and evolution of radiating dike swarms within the region, 2) use the diverse array of volcanic deposits to further test the neutral buoyancy hypothesis proposed to explain the origin of reservoir-derived features, 3&4) unravel the volcanic and tectonic evolution in this area, and 5) explore the implications of 1-4 for resurfacing mechanisms. Here we summarize our onging analysis of the material unit stratigraphy in the quadrangle, data central to meeting the aforementioned objectives successfully.

New Communitarianism Movements and Complex Utopia

NASA Astrophysics Data System (ADS)

Akdeniz, K. Gediz

Simulation is a rapidly growing field in social sciences. Simulation theories in social sciences are considered to critique social dynamics and societies which are mostly simulated by media, cinema, TV, internet, etc. Recently we (Akdeniz KG, Disorder in complex human system. In: Fritzsch H, Phua KK (eds) Singapore: proceedings of the conference in Honour of Murray Gell-Mann's 80th birthday quantum mechanics, elementary particles, quantum cosmology and complexity. World Scientific Publishing, Hackensack, pp 630-637, 2009) purposed a simulation theory as a critique theory to investigate disordered human behaviors. In this theory, "Disorder-Sensitive Human Behaviors (DSHB) Simulation Theory", chaotic awareness is also considered as a reality principle in simulation world to complete Baudrillard Simulation Theory (Baudrillard J, Simulacra and simulation. University of Michigan Press, Michigan, 1995). We call the emergence of this reality as zuhur which is different than simulacra. More recently we proposed the complex utopia (Akdeniz KG, From Simulacra to Zuhur in Complex Utopia. 11th International Conference of the Utopian Studies Society, Lublin, 2010; Akdeniz KG, The new identities of the physicist: cyborg-physicist and post-physicist. In: Proceedings of the conference of world international conference of technology and education, Beirut, 2010) to critique the complex societies and communities in simulation world. The challenging agents in the complex utopia are both simulacra and zuhur. In this paper we would like to review "What is the complex utopia?" And we shall critique some global events in framework of complex utopia with particular examples in socio-economic and political contexts.

Methane Seepage on Mars: Where to Look and Why

NASA Astrophysics Data System (ADS)

Oehler, Dorothy Z.; Etiope, Giuseppe

2017-12-01

Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as "gas seepage." Here, we review the variety of subsurface processes that could result in methane seepage on Mars. Such methane could originate from abiotic chemical reactions, thermogenic alteration of abiotic or biotic organic matter, and ancient or extant microbial metabolism. These processes can occur over a wide range of temperatures, in both sedimentary and igneous rocks, and together they enhance the possibility that significant amounts of methane could have formed on early Mars. Methane seepage to the surface would occur preferentially along faults and fractures, through focused macro-seeps and/or diffuse microseepage exhalations. Our work highlights the types of features on Mars that could be associated with methane release, including mud-volcano-like mounds in Acidalia or Utopia; proposed ancient springs in Gusev Crater, Arabia Terra, and Valles Marineris; and rims of large impact craters. These could have been locations of past macro-seeps and may still emit methane today. Microseepage could occur through faults along the dichotomy or fractures such as those at Nili Fossae, Cerberus Fossae, the Argyre impact, and those produced in serpentinized rocks. Martian microseepage would be extremely difficult to detect remotely yet could constitute a significant gas source. We emphasize that the most definitive detection of methane seepage from different release candidates would be best provided by measurements performed in the ground or at the ground-atmosphere interface by landers or rovers and that the technology for such detection is currently available.

Could giant basin-forming impacts have killed Martian dynamo?

PubMed Central

Kuang, W; Jiang, W; Roberts, J; Frey, H V

2014-01-01

The observed strong remanent crustal magnetization at the surface of Mars suggests an active dynamo in the past and ceased to exist around early to middle Noachian era, estimated by examining remagnetization strengths in extant and buried impact basins. We investigate whether the Martian dynamo could have been killed by these large basin-forming impacts, via numerical simulation of subcritical dynamos with impact-induced thermal heterogeneity across the core-mantle boundary. We find that subcritical dynamos are prone to the impacts centered on locations within 30° of the equator but can easily survive those at higher latitudes. Our results further suggest that magnetic timing places a strong constraint on postimpact polar reorientation, e.g., a minimum 16° polar reorientation is needed if Utopia is the dynamo killer. PMID:26074641

Could Giant Basin-Forming Impacts Have Killed Martian Dynamo?

NASA Technical Reports Server (NTRS)

Kuang, W.; Jiang, W.; Roberts, J.; Frey, H. V.

2014-01-01

The observed strong remanent crustal magnetization at the surface of Mars suggests an active dynamo in the past and ceased to exist around early to middle Noachian era, estimated by examining remagnetization strengths in extant and buried impact basins. We investigate whether the Martian dynamo could have been killed by these large basin-forming impacts, via numerical simulation of subcritical dynamos with impact-induced thermal heterogeneity across the core-mantle boundary. We find that subcritical dynamos are prone to the impacts centered on locations within 30 deg of the equator but can easily survive those at higher latitudes. Our results further suggest that magnetic timing places a strong constraint on postimpact polar reorientation, e.g., a minimum 16 deg polar reorientation is needed if Utopia is the dynamo killer.

Could giant basin-forming impacts have killed Martian dynamo?

PubMed

Kuang, W; Jiang, W; Roberts, J; Frey, H V

2014-11-28

The observed strong remanent crustal magnetization at the surface of Mars suggests an active dynamo in the past and ceased to exist around early to middle Noachian era, estimated by examining remagnetization strengths in extant and buried impact basins. We investigate whether the Martian dynamo could have been killed by these large basin-forming impacts, via numerical simulation of subcritical dynamos with impact-induced thermal heterogeneity across the core-mantle boundary. We find that subcritical dynamos are prone to the impacts centered on locations within 30° of the equator but can easily survive those at higher latitudes. Our results further suggest that magnetic timing places a strong constraint on postimpact polar reorientation, e.g., a minimum 16° polar reorientation is needed if Utopia is the dynamo killer.

Identification of the Beagle 2 lander on Mars.

PubMed

Bridges, J C; Clemmet, J; Croon, M; Sims, M R; Pullan, D; Muller, J-P; Tao, Y; Xiong, S; Putri, A R; Parker, T; Turner, S M R; Pillinger, J M

2017-10-01

The 2003 Beagle 2 Mars lander has been identified in Isidis Planitia at 90.43° E, 11.53° N, close to the predicted target of 90.50° E, 11.53° N. Beagle 2 was an exobiology lander designed to look for isotopic and compositional signs of life on Mars, as part of the European Space Agency Mars Express (MEX) mission. The 2004 recalculation of the original landing ellipse from a 3-sigma major axis from 174 km to 57 km, and the acquisition of Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment (HiRISE) imagery at 30 cm per pixel across the target region, led to the initial identification of the lander in 2014. Following this, more HiRISE images, giving a total of 15, including red and blue-green colours, were obtained over the area of interest and searched, which allowed sub-pixel imaging using super high-resolution techniques. The size (approx. 1.5 m), distinctive multilobed shape, high reflectivity relative to the local terrain, specular reflections, and location close to the centre of the planned landing ellipse led to the identification of the Beagle 2 lander. The shape of the imaged lander, although to some extent masked by the specular reflections in the various images, is consistent with deployment of the lander lid and then some or all solar panels. Failure to fully deploy the panels-which may have been caused by damage during landing-would have prohibited communication between the lander and MEX and commencement of science operations. This implies that the main part of the entry, descent and landing sequence, the ejection from MEX, atmospheric entry and parachute deployment, and landing worked as planned with perhaps only the final full panel deployment failing.

Identification of the Beagle 2 lander on Mars

PubMed Central

Clemmet, J.; Croon, M.; Sims, M. R.; Pullan, D.; Muller, J.-P.; Tao, Y.; Xiong, S.; Putri, A. R.; Parker, T.; Turner, S. M. R.; Pillinger, J. M.

2017-01-01

The 2003 Beagle 2 Mars lander has been identified in Isidis Planitia at 90.43° E, 11.53° N, close to the predicted target of 90.50° E, 11.53° N. Beagle 2 was an exobiology lander designed to look for isotopic and compositional signs of life on Mars, as part of the European Space Agency Mars Express (MEX) mission. The 2004 recalculation of the original landing ellipse from a 3-sigma major axis from 174 km to 57 km, and the acquisition of Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment (HiRISE) imagery at 30 cm per pixel across the target region, led to the initial identification of the lander in 2014. Following this, more HiRISE images, giving a total of 15, including red and blue-green colours, were obtained over the area of interest and searched, which allowed sub-pixel imaging using super high-resolution techniques. The size (approx. 1.5 m), distinctive multilobed shape, high reflectivity relative to the local terrain, specular reflections, and location close to the centre of the planned landing ellipse led to the identification of the Beagle 2 lander. The shape of the imaged lander, although to some extent masked by the specular reflections in the various images, is consistent with deployment of the lander lid and then some or all solar panels. Failure to fully deploy the panels—which may have been caused by damage during landing—would have prohibited communication between the lander and MEX and commencement of science operations. This implies that the main part of the entry, descent and landing sequence, the ejection from MEX, atmospheric entry and parachute deployment, and landing worked as planned with perhaps only the final full panel deployment failing. PMID:29134081

Identification of the Beagle 2 lander on Mars

NASA Astrophysics Data System (ADS)

Bridges, J. C.; Clemmet, J.; Croon, M.; Sims, M. R.; Pullan, D.; Muller, J.-P.; Tao, Y.; Xiong, S.; Putri, A. R.; Parker, T.; Turner, S. M. R.; Pillinger, J. M.

2017-10-01

The 2003 Beagle 2 Mars lander has been identified in Isidis Planitia at 90.43° E, 11.53° N, close to the predicted target of 90.50° E, 11.53° N. Beagle 2 was an exobiology lander designed to look for isotopic and compositional signs of life on Mars, as part of the European Space Agency Mars Express (MEX) mission. The 2004 recalculation of the original landing ellipse from a 3-sigma major axis from 174 km to 57 km, and the acquisition of Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment (HiRISE) imagery at 30 cm per pixel across the target region, led to the initial identification of the lander in 2014. Following this, more HiRISE images, giving a total of 15, including red and blue-green colours, were obtained over the area of interest and searched, which allowed sub-pixel imaging using super high-resolution techniques. The size (approx. 1.5 m), distinctive multilobed shape, high reflectivity relative to the local terrain, specular reflections, and location close to the centre of the planned landing ellipse led to the identification of the Beagle 2 lander. The shape of the imaged lander, although to some extent masked by the specular reflections in the various images, is consistent with deployment of the lander lid and then some or all solar panels. Failure to fully deploy the panels-which may have been caused by damage during landing-would have prohibited communication between the lander and MEX and commencement of science operations. This implies that the main part of the entry, descent and landing sequence, the ejection from MEX, atmospheric entry and parachute deployment, and landing worked as planned with perhaps only the final full panel deployment failing.

Midlatitude Ice-Rich Ground on Mars: An Important Target for Science and In Situ Resource Utilization on Human Missions

NASA Technical Reports Server (NTRS)

Stoker, Carol; Heldmann, Jennifer

2015-01-01

The region of ROI is characterized by proven presence of near surface ground ice and numerous periglacial features. Midlatitude ground ice on Mars is of significant scientific interest for understanding the history and evolution of ice stability on Mars, the impact that changes in insolation produced by variations in Mars’ orbital parameters has on the regions climate, and could provide human exploration with a reliable and plentiful in situ resource. For both science and exploration, assessing the astrobiological potential of the ice is important in terms of (1) understanding the potential for life on Mars and (2) evaluating the presence of possible biohazards in advance of human exploration. Heldmann et al. (2014) studied locations on Mars in the Amazonis Planitia region where near surface ground ice was exposed by new impact craters (Byrne et al. 2009). The study examined whether sites in this region were suitable for human exploration including reviewing the evidence for midlatitude ground ice, discussing the possible explanations for its occurrence, assessing its potential habitability for modern life, and evaluating the resource potential. They systematically analyzed remote-sensing data sets to identify a viable landing site. Five sites where ground ice was exposed were examined with HiRise imaging and were classified according to (1) presence of polygons as a proxy for subsurface ice, (2) presence and abundance of rough topographic obstacles (e.g., large cracks, cliffs, uneven topography), (3) rock density, (4) presence and abundance of large boulders, and (5) presence of craters. A suitable landing site was found having ground ice at only 0.15m depth, and no landing site hazards within a 25 km landing ellipse. This paper presents results of that study and examines the relevance of this ROI to the workshop goals.

Cerberus Fossae, Elysium, Mars: a source for lava and water

NASA Astrophysics Data System (ADS)

Plescia, J. B.

2003-07-01

Cerberus Fossae, a long fracture system in the southeastern part of Elysium, has acted as a conduit for the release of both lava and water onto the surface. The southeastern portion of the fracture system localized volcanic vents having varying morphology. In addition, low shields occur elsewhere on the Cerberus plains. Three locations where the release of water has occurred have been identified along the northwest (Athabasca and Grjota' Vallis) and southeast (Rahway Vallis) portions of the fossae. Water was released both catastrophically and noncatastrophically from these locations. A fluvial system that extends more than 2500 km has formed beginning at the lower flank of the Elysium rise across the Cerberus plains and out through Marte Vallis into Amazonis Planitia. The timing of the events is Late Amazonian.

Geomorphology and Geology of the Southwestern Margaritifer Sinus and Argyre Regions of Mars. Part 1: Geological and Geomorphological Overview

NASA Technical Reports Server (NTRS)

Parker, T. J.; Pieri, D. C.

1985-01-01

Based upon Viking Orbiter 1 images of the southwestern portion of the Margaritifer Sinus Quadrangle, the northwestern portion of the Argyre Quadrangle, and a small portion of the southeastern Coprates Quadrangle, three major mountainous of plateau units, seven plains units, and six units related to valley forming processes were identified. The photomosaic is oriented such that it provides good areal coverage of the upper Chryse Trough from Argyre Planitia to just above Margaritifer Chaos as well as of plains units on either side of the Trough. The photomosaic was compiled from Viking Orbiter 1 images ranging in resolution from approximately 150 to 300 meters per pixel printed at a scale of about 1:2,000,000. The characteristics of each geomorphic unit are outlined.

Morphology of cone-fields in SW Elysium Planitia - Traces of hydrothermal venting on Mars?

NASA Astrophysics Data System (ADS)

Lanz, J. K.; Saric, M. B.

2008-09-01

Introduction Small cone-shaped features with summit pits can be found in several regions on Mars; mainly in Isidis Planitia; Elysium Planitia; Amazonis Planitia; Acidalia Planitia; in the Cydonia Region; in Cerberus Planum; the Phlegra Montes and on several volcanic flanks. They vary greatly in size and morphology and have been compared to terrestrial features of various origins; namely (1) cinder cones (e.g. [1]), (2) tuff cones or tuff rings (e.g. [2]), (3) rootless cones (pseudocraters) (e.g. [3], [4]), (4) pingos (e.g. [5], [6]) and (5) mud volcanoes (e.g. [7]). They are often found near volcanic centers and large lava fields or cluster in regions where the volatile content of the Martian regolith was/is supposedly high. This has led to the assumption that (ground-) water or ground ice was a trigger or driving force of cone formation. They could therefore, be an important indicator of the history of water on the planet. We have studied an area in western Elysium Planitia, bordering the Aeolis Planum plateau, which exhibits a large number of pitted cones, ridges and dome-like structures. Their distribution and morphology differs strongly from pitted cones elsewhere in Elysium Planitia, which have mainly been interpreted as hydrovolcanic rootless cones, and from other regions on Mars. Based on our observations, we present an alternative model for cone formation in the study area that might hint towards hydrothermal processes in the Aeolis Planum region and possibly young igneous activity. Aeolis Planum Cones The Aeolis Planum pitted cones (referred to as APCs from now on) cluster along the southern edges of the broad shallow valley that borders the Aeolis Planum Formation (APF) to the north. Cones along the northern edges of the valley are rare and can only be found in association with APF remnants where they strongly resemble the cones in the south. Along the southern border the cone coverage is almost continuous, describing a narrow band approximately 2 to 3 km wide. There are distinct morphological changes both within the band from north to south and along the band from east to west (Fig. 2). The cones are mostly circular but elongated, irregular forms are common. They are of varying size with basal diameters ranging from 20 to 200 meters, though most (single) cones have basal diameters below 100 meters. The heights of the cones are difficult to determine as their sizes are far below the resolution limits of either MOLA or HRSC stereo data, yet photoclinometric calculations have given approximate heights between ~ 10 up to several dozens of meters. Often the cones show hardly any elevation above the surroundings (e.g. Fig. 2c, e or f). Most of the APCs have steep convex flanks and large summit pits with diameters at least half as wide as their bases. The overall morphology of the cones changes from S to N with distance from the APF and from E to W along the edges of the APF. Toward the south, close to the strongly eroded borders of the APF, broad ridges and elongated domes are dominant. They form a narrow band approximately 2 km wide. The ridges and domes are a few dozen to several hundred meters long and between 10 to 50 meters wide and show numerous cracks and fissures. They are often topped by small cones, elongated pits and remnants of APF sediments. Further north follows a rather abrupt transition from the ridged area to more cone-dominated regions. Here single cones are prevalent with a more random distribution. Their number decreases rapidly with increasing distance from the APF and approximately 3 km off the southern edge of the APF no further cones are found. Hydrothermal venting on Mars? Morphology and stratigraphic relationships indicate that the cones are young and that they have, at least in places, developed inside the APF complex. APF remnants can be found covering the central pits of cones and APF units have been tilted and eroded by coneforming processes. Furthermore, cones are mainly found inside a narrow band 2-3 km wide along the APF-lava contact. A connection between APF-lava interaction and cone-forming processes is therefore likely. We propose that a combination of contact metamorphosis and associated hydrothermal venting comparable to hydrothermal vent complexes on Earth could have been the driving force of cone-formation in the study area based on the assumption of a high volatile content of the APF. The processes might then have proceeded as follows: Phase 1: The flooding of the study area by lava caused initial explosive reactions along the lava-APF-boundary forming clusters of pseudocraters. Pseudocraters are only visible towards the edges of the depression where the lava cover is thinnest. Towards the center the thick lava coverage prevented pseudocrater formation or quickly reburied forming cones. Phase 2: The heat of the cooling lava, which could be as thick as 500 m based on the diameters of flooded craters, causes contact metamorphosis and the mobilization of volatiles in the surrounding APF-sediments. Similar to hydrothermal vent complexes on Earth, this may have caused hydrofracturing of the sediments and the formation of sediment pipes and dikes that transport the volatiles to the surface. Pre-existing fissures would have served as additional pathways. At the surface rapid decompression causes phreatic explosions and the formation of small cones. Phase 3: Close to the lava-body mobilization of volatiles (e.g. by dehydratation of hydrated minerals, mobilization of ground- or pore ice or even juvenile waters and other volatiles from the lava itself) was strongest. In combination with lower sediment thickness and shorter pathways to the surface, phreatic explosion were more violent and conduits may have been repeatedly active. The lower atmospheric pressure and lower gravity on Mars would have further enhanced the explosive activity. While the lower gravity leads to a faster ascent of the volatile-sediment-phase, thereby preventing early degassing, the lower atmospheric pressure causes stronger decompression and expansion of gases. With increasing distance and increasing APF-thickness the surface manifestation of the processes weakens and phreatic explosive activity decreases. The cracked domes and elongated ridges may then be the surface expression of sediment pipes and dikes that have cooled and degassed before reaching the surface. The flow structures surrounding many cones and ridges could be interpreted in this context as fluidized sediment as lava would not have been discharged from the vents. This kind of sediment volcanism took place after the erosion of the APF and marks the end of the hydrothermal activity. Phase 4: Erosion of the APF, enhanced by the cone-forming processes themselves, later exhumed deeper parts of the vents and the brecciated sediment cores, leaving remnants of APF sediments in central pits and on top of cones, ridges and domes. References: [1] Plescia J. B. (1980) NASA Tech. Memo., 82385, 263-265. [2] Bridges J. C. et al. (2003) JGR, 180(E1), 5001, doi:10.1029/2001JE001820. [3] Fagents S. A. (2002) LPSC XXXIII, Abstract #1594. [4] Bruno B. C. (2004) JGR, 109, doi:1029/2004JE002273. [5] Theilig E. and Greeley R. (1979) J. Geophys. Res., 84, 7994-8010. [6] Page and Murray (2006) Icarus, 183, 46-54. [7] Skinner J. A. and Tanaka K. L. (2006) Icarus, 186, 41-59. [7] Watters T. R. et al. (2007) Sciencexpress, science. 1148112, 10.1126.

Mars Pathfinder Landing Site Workshop 2: Characteristics of the Ares Vallis Region and Field Trips in the Channeled Scabland, Washington

NASA Technical Reports Server (NTRS)

Golombek, M. P. (Editor); Edgett, K. S. (Editor); Rice, J. W. , Jr. (Editor)

1995-01-01

Mars Pathfinder will place a single lander on the surface of Mars on July 4, 1997, following a December 1996 launch. As a result of the very successful first Mars Pathfinder Landing Site Workshop, the project has selected the Ares Vallis outflow channel in Chryse Planitia as the landing site. This location is where a large catastrophic outflow channel debouches into the northern lowlands. A second workshop and series of field trips, entitled Mars Pathfinder Landing Site Workshop 2: Characteristics of the Ares Vallis Region and Field Trips in the Channeled Scabland, Washington, were held in Spokane and Moses Lake, Washington. The purpose of the workshop was to provide a focus for learning as much as possible about the Ares Vallis region on Mars before landing there. The rationale is that the more that can be learned about the general area prior to landing, the better scientists will be able interpret the observations made by the lander and rover and place them in the proper geologic context. The field trip included overflights and surface investigations of the Channeled Scabland (an Earth analog for the martian catastrophic outflow channels), focusing on areas particularly analogous to Ares Vallis and the landing site. The overflights were essential for placing the enormous erosional and depositional features of the Channeled Scabland into proper three-dimensional context. The field trips were a joint educational outreach activity involving K-12 science educators, Mars Pathfinder scientists and engineers, and interested scientists from the Mars scientific community. Part 1 of the technical report on this workshop includes a description of the Mars Pathfinder mission, abstracts accepted for presentation at the workshop, an introduction to the Channeled Scabland, and field trip guides for the overflight and two field trips. This part, Part 2, includes the program for the workshop, summaries of the workshop technical sessions, a summary of the field trips and ensuing discussions, late abstracts of workshop presentations, reports on the education and public outreach activities carried out by the educators, and a list of the workshop and field trip participants.

Dust Devil Track Occurrence in Argyre Planitia.

NASA Astrophysics Data System (ADS)

Whelley, P. L.; Balme, M. R.; Greeley, R.

2002-12-01

Martian dust devil tracks were first observed in Viking Orbiter images [Thomas et al., 1985]. While the interpretation of these features was at first controversial, it is now widely accepted that the tracks are formed by the passage of small convective vortices (dust devils). As the dust devils travel across the surface the atmosphere is loaded with fine particles creating a visible trail inferred to be removal or deposition of material [Greeley et al., 2001]. Mars Global Surveyor (MGS) Mars Orbital Camera (MOC) images of dust devil tracks in Argyre Planitia were used to asses dust devil track abundance as a function of Martian season as well as elevation using Mars Orbiter Laser Altimeter (MOLA) data. Argyre Planitia is a large impact basin in the southern hemisphere (55° to 33°W and 35° to 58°S), with topographic relief of 7 km with the median at -1km. We have studied the 564 Narrow Angle MOC images (taken as of summer 2002) covering the area. The images were divided into two categories: those with devil tracks and those without. The Ls (solar longitude degrees as a fraction of orbit) and elevation of all of the images with and without devil tracks were noted. The elevation was recorded at the center point of each MOC image using MOLA data. A polar plot of all of the images shows a statistically random distribution throughout the Martian year. A context map of the images shows a representative distribution over the area of the crater itself. A polar plot of dust devil track occurrence within the area observed shows a major concentration of tracks between Ls 200° and 360° (southern spring to late summer). A seasonal breakdown of devil track occurrence as a percentage of total area observed yields: fall 11.25%, winter 2.24%, spring 27.21%, and summer 46.49%. We therefore conclude that dust devils tracks are formed preferentially in summer and are destroyed, fade or are covered, over a period of a few months. The elevation of all 564 images was measured and 1km bins were used to calculate the percent of occurrence. We discovered that, at 3km 0% of the observed area contain dust devil tracks, 2km 7.69%, 1km 12.90%, at Datum 15.95%, -1km 8.97%, -2km 28.92%, -3km% 50.00%, -4km 50.00%. Independent of the season a majority of the devil tracks were observed below -3km. Therefore elevation is a key factor governing the formation of dust devils or their ability to produce tracks. Our interpretation of these results is that dust devils are much more likely to form during the summer and, as suggested by recent experiments [Balme et al., 2002], that they are more efficient at moving materials on the surface in areas where the atmospheric pressure is greatest (in the lowest elevations). The short timescale for disappearance of tracks suggests that the distinct albedo variations of the tracks result from only the removal or deposition of a very thin layer of material. Thomas. P. et al., 1985, Science v. 230 Greeley. R. et al., 2001, LPSC XXXII Balme. M. et al., 2002, LPSC XXXIII

Reorientation and faulting of Pluto due to volatile loading within Sputnik Planitia.

PubMed

Keane, James T; Matsuyama, Isamu; Kamata, Shunichi; Steckloff, Jordan K

2016-12-01

Pluto is an astoundingly diverse, geologically dynamic world. The dominant feature is Sputnik Planitia-a tear-drop-shaped topographic depression approximately 1,000 kilometres in diameter possibly representing an ancient impact basin. The interior of Sputnik Planitia is characterized by a smooth, craterless plain three to four kilometres beneath the surrounding rugged uplands, and represents the surface of a massive unit of actively convecting volatile ices (N 2 , CH 4 and CO) several kilometres thick. This large feature is very near the Pluto-Charon tidal axis. Here we report that the location of Sputnik Planitia is the natural consequence of the sequestration of volatile ices within the basin and the resulting reorientation (true polar wander) of Pluto. Loading of volatile ices within a basin the size of Sputnik Planitia can substantially alter Pluto's inertia tensor, resulting in a reorientation of the dwarf planet of around 60 degrees with respect to the rotational and tidal axes. The combination of this reorientation, loading and global expansion due to the freezing of a possible subsurface ocean generates stresses within the planet's lithosphere, resulting in a global network of extensional faults that closely replicate the observed fault networks on Pluto. Sputnik Planitia probably formed northwest of its present location, and was loaded with volatiles over million-year timescales as a result of volatile transport cycles on Pluto. Pluto's past, present and future orientation is controlled by feedbacks between volatile sublimation and condensation, changing insolation conditions and Pluto's interior structure.

Physical properties of the surface materials at the Viking landing sites on Mars

USGS Publications Warehouse

Moore, H.J.; Hutton, R.E.; Clow, G.D.; Spitzer, C.R.

1987-01-01

This report summarizes the results of the Physical Properties Investigation of the Viking '75 Project, activities of the surface samplers, and relevant results from other investigations. The two Viking Landers operated for nearly four martian years after landing on July 20 (Lander 1) and Sept. 3 (Lander 2), 1976; Lander 1 acquired its last pictures on or about Nov. 5, 1982. Lander 1 rests on a smooth, cratered plain at the west edge of Chryse Planitia (22.5 ? N, 48.0? W), and Lander 2 rests 200 km west of the crater Mie in Utopia Planitia (48.0? N, 225.7? W). Lander 1 views showed that dune-like deposits of drift material were superposed on rock-strewn surfaces. Soil-like material from the rock-strewn areas was called blocky material. Lander 2 views also showed a rock-strewn surface. Polygonal to irregular features, etched by the wind, revealed crusty to cloddy material among rocks. Both landers descended to the surface along nearly vertical trajectories. Velocities at touchdown were about 2 m/s for both landers. Footpad 2 of Lander 1 penetrated drift material 0.165 m, and footpad 3 penetrated blocky material 0.036 m. The two visible footpads of Lander 2 struck rocks. Erosion by exhausts from the forward engines produced craters with rims of mixed fine-grained material and platy to equidimensional clods, crusts, and fragments. Comparison of engine-exhaust erosion on Mars with terrestrial data suggested that drift material behaved like a weakly cohesive material with a grain size less than 3-9 /-lm. Although not sand, blocky and crusty to cloddy materials eroded like sand-with grain sizes of 0.01 or 0.2 cm. The surface samplers accomplished an impressive number of tasks. All experiments that required samples received samples. Deep holes, as much as 0.22 m deep, were excavated by both landers. Lander 2 successfully pushed rocks and collected samples from areas originally beneath the rocks. Tasks specifically accomplished for the Physical Properties Investigation include: (1) acquiring motor-current data while excavating trenches, (2) performing surface-bearing tests, (3) performing backhoe touchdowns, (4) attempting to chip or scratch rocks, (5) comminuting samples, (6) measuring subsurface diurnal temperatures, and (7) constructing conical piles of materials on and among rocks. Sample trenches in the three major types of soil-like materials were different from one another. Trenches in drift material, which were typically 0.06 m deep, had steep walls along much of their lengths, lumpy tailings and floors, and smooth domed surfaces with sparse fine fractures around their tips. Trenches in blocky material, which were typically 0.03-0.04 m deep, had steep walls near their tips, and surfaces around their tips were displaced upward and some appeared blocky. Trenches in crusty to cloddy material, which were typically 0.04-0.05 m deep, had steep and often irregular slopes near their tips, clods and slabs of crust in their tailings, and disrupted areas around their tips composed of mixed fine-grained material and slabs of crust or thick polygonal clods that had been displaced upwards. Data acquired during landing, trenching, surface-bearing tests, backhoe touchdowns, and from other science experiments were used to determine the mechanical properties of drift, blocky, and crusty to cloddy materials. Drift material appeared to be very fine grained, with local planes of weakness; in general, the drift material was consistent with a material having an angle of internal friction about 18?, a cohesion ranging from 0.7 to 3.0 kPa, and a bulk density of 1,200 kg/m 3 . Blocky material was consistent with a material having an angle of internal friction about 30?, cohesions from 1.5 to 16 kPa, and a bulk density of 1,600 kg/m 3 . Crusty to cloddy material had variable properties. For chiefly crusty to cloddy material, angles of internal friction were about 35 ? , and cohesions were from 0.5 to 5.2 kPa. For mixed fines and crusts, a

Physical properties of Oxia/Lunae Planum and Arabia-type units in the central equatorial region of Mars

NASA Technical Reports Server (NTRS)

Strickland, Edwin L., III

1992-01-01

Classification and mapping of surficial units in the central equatorial region of Mars Consortium data identified the relatively dark but 'red' materials that cover Lunae Planum and surround the Meridiani materials of Oxia Palus inertia region of Arabia. Oxia Province consists of the regions dominated by the characteristically dark 'red' Oxia materials, but it includes darker streaks and splotches of relatively 'blue' Meridiani materials and brighter 'red' deposits of dust belonging to Eos Province (the bright 'red' border between Oxia and regional Meridiani deposits to the south) and Xanthe Province (the moderately bright 'red' dust deposits in western Chryse Planitia and its vicinity, including the VL-1 landing site). Two Oxia units were recognized: a darker unit present on Lunae Planum and east of Oxia Palus that have intermediate to high inertias. Oxia Province surrounds the extremely low thermal inertia Arabia Province in the east part of the study area, and occurs as isolated patches within Arabia (often including splotches of Meridiani materials within the Oxia patches). Arabia Province's materials have been widely interpreted as unconsolidated dust deposits which are currently forming at this stage of Mars' precessional climate cycle, although the persistence of stable, moderately strong albedo contracts among Arabia materials has not been addressed in those models. A systematic interpretation of Oxia and Arabia Province materials based on currently available remote sensing data is given.

Determination of the Beagle2 landing site

NASA Astrophysics Data System (ADS)

Trautner, R.; Manaud, N.; Michael, G.; Griffiths, A.; Beauvivre, S.; Koschny, D.; Coates, A.; Josset, J.-L.

2004-02-01

Beagle2 is the UK-led lander element on ESA's Mars Express mission, which will reach Mars in late December 2003. After separation from the Mars Express orbiter 6 days before the atmospheric entry, Beagle2 will descend to the Martian surface by means of ablative heat shields and parachutes. The impact will be cushioned by a set of airbags. The selected landing site at 11.6 deg N/90.75 deg E (IAU 2000 coordinates) is situated in the south-east of the center of Isidis Planitia, a sedimentary basin which is expected to meet the requirements of Beagle's scientific mission, the lander operations, and the entry, descent and landing systems. The exact determination of the Beagle2 landing site is important not only for the Beagle2 and MEX orbiter science investigations, but also for the reconstruction of Beagle's entry and descent trajectory. A precise determination of the Beagle2 position is not possible via the MELACOM radio link. Instead, a novel method based on celestial navigation is employed, which utilizes the Stereo Camera System on the lander for imaging the Martian night sky. The position data is then refined by comparing the landing site panorama images with high resolution orbiter images and laser altimeter data. This combination of celestial navigation with image data analysis for precision position determination will be applicable for many future missions as well.

Map of Martian Potassium at Mid-Latitudes

NASA Technical Reports Server (NTRS)

2003-01-01

This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element potassium. Potassium, having the chemical symbol K, is a naturally radioactive element and is a minor constituent of rocks on the surface of both Mars and Earth. The region of highest potassium content, shown in red, is concentrated in the northern part of Acidalia Planitia (centered near 55 degrees N, -30 degrees). Several areas of low potassium content, shown in blue, are distributed across the mid-latitudes, with two significant low concentrations, one associated with the Hellas Basin (centered near 35 degrees S, 70 degrees) and the other lying southeast of Elysium Mons (centered near 10 degrees N, 160 degrees). Contours of constant surface elevation are also shown. The long continuous line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Sedna Planitia Right Member of a Synthetic Stereo Pair

NASA Image and Video Library

1998-06-04

This perspective view of Venus, generated by computer from NASA Magellan data and color-coded with emissivity, shows part of the lowland plains in Sedna Planitia. http://photojournal.jpl.nasa.gov/catalog/PIA00314

Carl Sagan's Cosmic Connection

NASA Astrophysics Data System (ADS)

Sagan, Carl; Agel, Jerome

2000-08-01

Foreword Freeman Dyson; Personal reflections Ann Druyan; Preface; Part I. Cosmic Perspective: 1. A transitional animal; 2. The Unicorn of Cetus; 3. A message from earth; 4. A message to earth; 5. Experiments in utopias; 6. Chauvinism; 7. Space exploration as a human enterprise I. The scientific interest; 8. Space exploration as a human enterprise II. The public interest; 9. Space exploration as a human enterprise III. The historical interest; Part II. The Solar System: 10. On teaching the first grade; 11. 'The ancient and legendary Gods of old'; 12. The Venus detective story; 13. Venus is hell; 14. Science and 'intelligence'; 15. The moons of Barsoom; 16. The mountains of Mars I. Observations from earth; 17. The mountains of Mars II. Observations from space; 18. The canals of Mars; 19. The lost pictures of Mars; 20. The Ice Age and the cauldron; 21. Beginnings and ends of the Earth; 22. Terraforming the plants; 23. The exploration and utlization of the solar system; Part III. Beyond the Solar System: 24. Some of my best friends are dolphins; 25. 'Hello, central casting? Send me twenty extraterrestrials'; 26. The cosmic connection; 27. Extraterrestrial life: an idea whose time has come; 28. Has the Earth been visited?; 29. A search strategy for detecting extraterrestrial intelligence; 30. If we succeed 31. Cables, drums, and seashells; 32. The night freight to the stars; 33. Astroengineering; 34. Twenty questions: a classification of cosmic civilisations; 35. Galactic cultural exchanges; 36. A passage to elsewhere; 37. Starfolk I. A Fable; 38. Starfolk II. A future; 39. Starfolk III. The cosmic Cheshire cats; Epilog David Morrison; Index.

Buried and Visible Impact Basin Distribution on Mars: Comparison with Magnetization, Gravity and Crustal Thickness Models

NASA Technical Reports Server (NTRS)

Frey, Herbert

2003-01-01

The large population of buried impact basins found in MOLA elevation data on Mars provides compelling evidence for a pre-Noachian crust below the oldest visible Early Noachian surface units, and lowland crust below the younger plains that is Early Noachian in age, older than much of the visible highlands, but not as old as the buried pre-Noachian highlands. The large (D greater than 200 km) buried basins are suggested by Quasi-Circular Depressions (QCDs) that are not apparent in image data, and include features up to 3000 lun diameter in both the lowlands (Utopia) and highlands (a newly found "Ares Basin"). There are about a dozen QCDs larger than 1000 km diameter. We have placed these large features in a relative age sequence based on superimposed smaller QCD. Only the youngest and most obvious of these (Hellas, Argyre, Isidis) lack magnetic anomalies within their main rings. These all have an N(200) cumulative crater density of less than 2.5. Somewhat older lowland-making basins (Utopia, Chryse, Acidalia) with an N(200) age of approximately 3.0, have weak magnetic anomalies, and the oldest, most subdued basins (including Ares) with N(200) greater than 3.5 have many strong magnetic anomalies within their main ring. These older basins likely formed before the main magnetic field died. We have compared our inventory of large QCDs with the distribution of gravity anomalies and with a crustal thickness model which shows many roughly circular areas of thinner crust completely or partly surrounded by narrow regions of thicker crust. These have the structure expected for impact basins, and many of them do correspond to the visible or buried QCDs we previously identified. But there are cases where the crustal thickness feature is offset from the QCD found in topography alone, and there are also several, sometimes large examples of such features which do not coincide with QCDs previously identified. For example, we find several likely buried basins revealed in the crustal thickness data in the Arcadia and Amazonis regions which we did not previously identify, including several features in the 600-1200 km diameter range.

Analysis of the Tectonic Lineaments in the Ganiki Planitia (V14) Quadrangle, Venus

NASA Technical Reports Server (NTRS)

Venechuk, E. M.; Hurwitz, D. M.; Drury, D. E.; Long, S. M.; Grosfils, E. B.

2005-01-01

The Ganiki Planitia quadrangle, located between the Atla Regio highland to the south and the Atalanta Planitia lowland to the north, is deformed by many tectonic lineaments which have been mapped previously but have not yet been assessed in detail. As a result, neither the characteristics of these lineaments nor their relationship to material unit stratigraphy is well constrained. In this study we analyze the orientation of extensional and compressional lineaments in all non-tessera areas in order to begin characterizing the dominant tectonic stresses that have affected the region.

VL1 Digs A Deep Hole On Mars

NASA Technical Reports Server (NTRS)

1977-01-01

VIKING LANDER DIGS A DEEP HOLE ON MARS -- This six-inch-deep, 12- inch-wide, 29-inch-long hole was dug Feb. 12 and 14 by Viking Lander 1 as the first sequence in an attempt to reach a foot beneath the surface of the red planet. The activity is in the same area where Lander 1 acquired its first soil samples last July. The trench was dug by repeatedly backhoeing in a left-right-center pattern. The backhoe teeth produced the small parallel ridges at the far end of the trench (upper left). The larger ridges running the length of the trench are material left behind during the backhoe operation. What appears to be small rocks along the ridges and in the soil at the near end of the trench are really small dirt clods. The clods and the steepness of the trench walls indicate the material is cohesive and behaves something like ordinary flour. After a later sequence, to be performed March 1 and 2, a soil sample will be taken from the bottom of the trench for inorganic soil analysis and later for biology analysis. Information about the soil taken from the bottom of the trench may help explain the weathering process on Mars and may help resolve the dilemma created by Viking findings that first suggest but then cast doubt on the possibility of life in the Martian soil. The trench shown here is a result of one of the most complex command sequences yet performed by the lander. Viking l has been operating at Chryse Planitia on Mars since it landed July 20, 1976.

Implications of Surface Morphologies for the Distribution of Shallow Subsurface Ice in Arcadia Planitia, Mars

NASA Astrophysics Data System (ADS)

Williams, N. R.; Hibbard, S. M.; Golombek, M. P.

2017-12-01

The plains of Arcadia Planitia on Mars at 40°N and 200°E straddle the southern boundary of a latitude-dependent mantle (LDM) of shallow water-ice that holds key records for the planet's climate. Ice is not stable at mid-latitude surfaces today, but is expected to have precipitated in the past during different obliquities and climatic conditions with remnant excess ice preserved in the subsurface under a veneer of soil partially isolating it from the atmosphere. Previous work has documented evidence for substantial ice in Arcadia using gamma ray spectrometry; ground-penetrating radar reflections and dielectric constants; and surface morphologies of lobate debris aprons, expanded secondary craters, terraced craters, and surface polygons. New high-resolution orbital images have been acquired that resolve meter-scale ice-related morphologies. In particular, Arcadia exhibits widespread polygonal patterned ground created by cryoturbation, and large areas of crenulated "brain coral" terrain for which the sinuous troughs have already undergone sublimation while the sinuous ridges are still ice-rich. We examined over 200 High Resolution Imaging Science Experiment (HiRISE) 25 cm/pixel images that resolve these morphologies indicating a complex transition of progressive ice loss at the edge of the LDM. HiRISE coverage is sparse across Arcadia; however, 6 m/pixel Context Camera (CTX) image coverage is nearly complete and fills in the gaps for terrain units with distinct textures. We find that crenulated terrain is restricted to a narrow latitude band at 38°N-43°N. Isolated shallow pits also occur northward of 40°N, and in many cases interconnect to form crenulations as part of a transitional morphologic continuum. Polygonal surface morphologies are ubiquitous farther north, but become increasingly sparse and more degraded farther south. These pits, crenulations, and polygons are sensitive to ice at depths of centimeters to a few meters, which could be easily accessible for future in-situ resource utilization. The latitude band of 38°N-43°N where these fine-scale morphologies occur represents the southern edge of the LDM where significant remnant ice is stored in the shallow subsurface.

Methane Seepage on Mars: Where to Look and Why.

PubMed

Oehler, Dorothy Z; Etiope, Giuseppe

2017-12-01

Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as "gas seepage." Here, we review the variety of subsurface processes that could result in methane seepage on Mars. Such methane could originate from abiotic chemical reactions, thermogenic alteration of abiotic or biotic organic matter, and ancient or extant microbial metabolism. These processes can occur over a wide range of temperatures, in both sedimentary and igneous rocks, and together they enhance the possibility that significant amounts of methane could have formed on early Mars. Methane seepage to the surface would occur preferentially along faults and fractures, through focused macro-seeps and/or diffuse microseepage exhalations. Our work highlights the types of features on Mars that could be associated with methane release, including mud-volcano-like mounds in Acidalia or Utopia; proposed ancient springs in Gusev Crater, Arabia Terra, and Valles Marineris; and rims of large impact craters. These could have been locations of past macro-seeps and may still emit methane today. Microseepage could occur through faults along the dichotomy or fractures such as those at Nili Fossae, Cerberus Fossae, the Argyre impact, and those produced in serpentinized rocks. Martian microseepage would be extremely difficult to detect remotely yet could constitute a significant gas source. We emphasize that the most definitive detection of methane seepage from different release candidates would be best provided by measurements performed in the ground or at the ground-atmosphere interface by landers or rovers and that the technology for such detection is currently available. Key Words: Mars-Methane-Seepage-Clathrate-Fischer-Tropsch-Serpentinization. Astrobiology 17, 1233-1264.

Observations and modeling of northern mid-latitude recurring slope lineae (RSL) suggest recharge by a present-day martian briny aquifer

NASA Astrophysics Data System (ADS)

Stillman, David E.; Michaels, Timothy I.; Grimm, Robert E.; Hanley, Jennifer

2016-02-01

Recurring slope lineae (RSL) are narrow (0.5-5 m) dark features on Mars that incrementally lengthen down steep slopes, fade in colder seasons, and recur annually. These features have been identified from the northern to southern mid-latitudes. Here, we describe how observations of northern mid-latitude RSL in northern Chryse Planitia and southwestern Acidalia Planitia (CAP) suggest that brines start flowing before northern spring equinox and continue for more than half a Mars-year (490 ± 40 sols, spanning solar longitude 337° ± 11°-224° ± 20°). All CAP RSL are found on the steep slopes of craters and their source zones are at or below the elevation of the surrounding plains. Spacecraft-derived surface temperature observations cannot resolve individual RSL, so thermal modeling was used to determine that CAP RSL have a freezing temperature of 238-252 K, freeze and melt diurnally, and flow only occurs within the top ∼8 cm of the regolith. Furthermore, we calculate that a typical CAP RSL has a water budget of 1.5-5.6 m3/m of headwall. Therefore, such a large water budget makes annual recharge via atmospheric or subsurface diffusion sources unlikely. Alternatively, we hypothesize that the most plausible RSL source is a briny aquifer with a freezing temperature less than or equal to the mean annual CAP surface temperature (220-225 K). The annual cycle is as follows: in late autumn, the shallowest part of the brine feeding the source zone freezes, forming an ice dam. As spring approaches, temperatures rise and the dam is breached. Brine is discharged and the RSL initially lengthens rapidly (>1.86 m/sol), the lengthening rate then slows considerably, to ∼0.25 m/sol. Eventually, the losses equal the discharge rate and the RSL reaches its equilibrium phase. As brine flows in the RSL some of the water is lost to the atmosphere, therefore the freezing temperature of the brine within the RSL is higher (238-252 K) as the brine transitions to a super-eutectic salt concentration. In the late autumn, falling temperatures restore the ice dam and the H2O in the RSL slowly sublimates away. Overall, CAP RSL possess a significantly different seasonality and much longer duration than typical southern mid-latitude RSL, suggesting that RSL at different latitude bands have different source types. Lastly, CAP RSL are the best evidence that shallow groundwater may still exist on Mars.

Magellan Perspective View of Sedna Planitia, 45° N, 11° E

NASA Image and Video Library

1998-06-04

This perspective view of Venus, generated by computer from NASA Magellan data and color-coded with emissivity, shows part of the lowland plains in Sedna Planitia. http://photojournal.jpl.nasa.gov/catalog/PIA00307

Teaching "Real Utopias" through Experiential Learning

ERIC Educational Resources Information Center

Peterson, Lindsey; Witt, Joseph; Huntington, Carolyn

2015-01-01

In this article, we describe a way to encourage students to envision "real utopias" through the Global Village experience at the Heifer Ranch in Arkansas. The Global Village experience introduces participants to issues associated with global hunger, poverty, environmental sustainability, and resource consumption and provides…

Possible Juventae Chasma subice volcanic eruptions and Maja Valles ice outburst floods on Mars: Implications of Mars Global surveyor crater densities, geomorphology, and topography

USGS Publications Warehouse

Chapman, M.G.; Gudmundsson, M.T.; Russell, A.J.; Hare, T.M.

2003-01-01

This article discusses image, topographic, and spectral data from the Mars Global Surveyor (MGS) mission that provide new information concerning the surface age, geomorphology, and topography of the Juventae Chasma/Maja Valles system. Our study utilizes data from two instruments on board MGS: images from the Mars Orbiter Camera (MOC) and topography from the Mars Orbiter Laser Altimeter (MOLA). Within Maja Valles we can now observe depositional bars with megaripples that unequivocally show catastrophic floods occurred in the channel. Viking impact crater densities indicated the chasma and channel floor areas were all one age (late Hesperian to Amazonian); however, MOC data indicate a marked difference in densities of small craters between Juventae Chasma, Maja Valles, and the channel debouchment area in Chryse Planitia basin. Although other processes may contribute to crater variability, young resurfacing events in the chasma and episodes of recent erosion at Maja Valles channel head may possibly account for the disparate crater densities along the chasma/channel system. Relatively young volcanic eruptions may have contributed to resurfacing; as in Juventae Chasma, a small possible volcanic cone of young dark material is observed. MOC data also indicate previously unknown interior layered deposit mounds in the chasma that indicate at least two periods of mound formation. Finally, MOLA topography shows that the entire floor of the chasma lies at the same elevation as the channel debouchment area in Chryse basin, resulting in a 3-km-high barrier to water flow out of the chasma. Blocked ponded water would rapidly freeze in the current (and likely past) climate of Mars. For catastrophic flow to occur in Maja Valles, some process is required to melt ice and induce floods out of the chasma. We suggest subice volcanic eruption and calculate estimates of water discharges and volumes that these eruptions might have produced.

Styles and timing of volatile-driven activity in the eastern Hellas region of Mars

NASA Astrophysics Data System (ADS)

Crown, David A.; Bleamaster, Leslie F.; Mest, Scott C.

2005-12-01

Recent analyses of Mars Global Surveyor and Mars Odyssey data sets provide new insights into the geologic evolution of the eastern Hellas region of Mars, in particular, the role of volatiles. Here, we present results of our recent work and integrate these with previous studies by various investigators to provide a synthesis of the history of volatile-driven activity of the region. We utilize high-resolution images from the Mars Orbiter Camera and Thermal Emission Imaging System combined with Mars Orbiter Laser Altimeter digital elevation models and profiles to examine fluvial systems that dissect the circum-Hellas highlands, to characterize stages in the development of the Dao, Niger, Harmakhis, and Reull Valles canyon systems, and to evaluate evidence for ancient lakes in Hellas Planitia. The occurrence of valley networks, dissected highland crater rims, and crater interior deposits such as layered plateaus suggests widespread ancient degradation of the circum-Hellas highlands. Canyon development, which represents subsequent more localized activity, may have included an early fluvial phase followed by the collapse and sapping dominated stages that, along with recent wall erosion and floor resurfacing, produced the currently observed morphologies. The prominent role of collapse and sapping along the east rim of Hellas, along with the presence of numerous channels extending toward the basin and sequences of finely layered deposits along the basin rim, suggests a volatile-rich substrate across a broad depositional shelf. The east rim of the basin was an accumulation zone for atmospheric volatiles and/or the edge of volatile-rich deposits associated with the basin floor. This evidence combined with topographic data and cratered terrain preservation around the basin is consistent with a lacustrine period or periods in early Martian history. The style, magnitude, and spatial extent of volatile-driven activity in eastern Hellas have varied considerably with time, and these variations may represent a transition from a water- to an ice-dominated surface environment.

A Sneak Peek into Saheki Secret Layers

NASA Image and Video Library

2017-04-04

This image from NASA's Mars Reconnaissance Orbiter is of Saheki Crater, about 84 kilometers across, and located in the Southern highlands of Mars, to the north of Hellas Planitia. It's filled with beautiful alluvial fans that formed when water (likely melting snow) carried fine material, such as sand, silt and mud, from the interior crater rim down to the bottom of the crater. Two smaller craters impacted into the alluvial fan surface in Saheki, excavating holes that allow us to see what the fans look like beneath the surface. Exposed along the crater's interior walls, we can see that the fan is made up of multiple individual layers (white and purple tones in the enhanced color image) that were deposited on the floor (the green and brown tones). The brown, circular shapes on the fan layers are small impact craters. The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 26.2 centimeters (10.3 inches) per pixel (with 1 x 1 binning); objects on the order of 78 centimeters (30.7 inches) across are resolved.] North is up. https://photojournal.jpl.nasa.gov/catalog/PIA21577

River of Sand

NASA Image and Video Library

2016-09-21

A dominant driver of surface processes on Mars today is aeolian (wind) activity. In many cases, sediment from this activity is trapped in low-lying areas, such as craters. Aeolian features in the form of dunes and ripples can occur in many places on Mars depending upon regional wind regimes. The Cerberus Fossae are a series of discontinuous fissures along dusty plains in the southeastern region of Elysium Planitia. This rift zone is thought to be the result of combined volcano-tectonic processes. Dark sediment has accumulated in areas along the floor of these fissures as well as inactive ripple-like aeolian bedforms known as "transverse aeolian ridges" (TAR). Viewed through HiRISE infrared color, the basaltic sand lining the fissures' floor stands out as deep blue against the light-toned dust covering the region. This, along with the linearity of the fissures and the wave-like appearance of the TAR, give the viewer an impression of a river cutting through the Martian plains. However, this river of sand does not appear to be flowing. Analyses of annual monitoring images of this region have not detected aeolian activity in the form of ripple migration thus far. http://photojournal.jpl.nasa.gov/catalog/PIA21063

Geologic map of the Snegurochka Planitia quadrangle (V-1), Venus

USGS Publications Warehouse

Hurwitz, Debra M.; Head, James W.

2012-01-01

The Snegurochka Planitia region is a predominantly low-lying terrain that covers the north polar region of Venus, extending from lat 75° N. to 90° N. and from long 0° E. to 360° E. The plains associated with Snegurochka Planitia abut the highlands of Metis Mons to the south from approximately long 240° E. to 300° E. (V–6) and the highlands of Ishtar Terra to the south from approximately long 300° E. to 60° E. (Lakshmi Planum, V–7; Fortuna Tessera, V–2). The plains of Louhi Planitia also lie within the V–1 region and form the northern border with the highlands of Tethus Regio from approximately long 60° E. to 120° E. (V–3 Meskhent Tessera) and with the lowlands of both Atalanta Planitia (V–4) and the nearby deformed region containing a series of ridged belts (V–5, Pandrosos Dorsa) from approximately long 120° E. to 240° E. The plains generally lie between +500 m and -500 m of the mean planetary radius (MPR) of 6051.8 km, with the highest terrain in the region, the northernmost extent of Ishtar Terra (Itzpapalotl Tessera, lat 75° N., long ~315° E.), rising more than 6.4 km above MPR.

Martian Weathering Environments of the Amazonian Indicated by Correlated Morphologic and Spectral Observation in Acidalia Planitia

NASA Astrophysics Data System (ADS)

Kraft, M. D.; Rogers, D.; Fergason, R. L.; Michalski, J. R.; Sharp, T. G.

2009-12-01

While much attention has been given to chemical alteration and the state of water on early Mars, it remains important to understand aqueous processes throughout Martian history, including the recent geologic past. It has been suggested that the Amazonian was marked primarily by anhydrous, oxidative weathering because Amazonian surfaces, such as the northern plains, lack hydration features in near-infrared spectra [1]. But high-silica materials (Surface Type 2, ST2) discovered by the Thermal Emission Spectrometer [2] that occur in the northern plains attest to aqueous alteration of silicate minerals. The questions are when did this occur and by what process? ST2 correlates spatially with outflow sediments and high-silica materials may have formed in large amounts of water related to outflow flooding events of the late Hesperian [3,4]. ST2 also may correspond to global ice-rich mantles, indicating formation in icy environments related to geologically recent climate fluctuations [3]. Can these very different mechanisms and environments be discerned? In a global study of TES spectra, Rogers et al. (2007) [5] found significant spectral differences between ST2 surfaces in northern and southern Acidalia Planitia that occur near 40-50° N. Several geomorphic transitions occur across latitudes, and many of these are directly or potentially related to Amazonian periglacial activity and occur in the 40-50° N range. This potential link between composition and periglacial morphology needs further exploration. We examined this relationship from 40-50° N in Acidalia Planitia, using Thermal Emission Imaging System (THEMIS) multispectral data to measure the local spectral properties of the surface. We identified a boundary between two surface spectral types that match closely the spectra of north and south Acidalia derived by Rogers et al. [2007]. This boundary is diffuse, occurring between 47-48° N in our study region in western Acidalia, and correlates with observed morphologic and thermophysical differences. Close examination of those surfaces with High Resolution Imaging Science Experiment (HiRISE) images shows that the area north of the boundary is a modified version of the southern surface, subdued and overprinted by periglacial polygonal ground. Thus, we think that ground ice has modified the surface morphology and, furthermore, that periglacial processing also modified the silicate composition of the northern surface materials. Weathering that created the northern Acidalia composition involved ground ice, and was likely similar to weathering in Antarctic soils, in which silica is mobilized by thin water films and deposited as gels [6]. By this mechanism, aqueous weathering on Mars has probably persisted into, and throughout, the Amazonian. References: [1] Bibring et al. (2006) Science, 312, 400-404. [2] Bandfield et al. (2000) Science, 287, 1626-1630. [3] Wyatt et al. (2004) Geology, 32, 645-648. [4] Tanaka et al. (2005) USGS Sci. Invest. Map 2888. [5] Rogers et al. (2007) J. Geophys. Res.,112, E02004. [6] Ugolini and Anderson (1973), Soil Sci., 105, 461-470.

The nitrogen cycles on Pluto over seasonal and astronomical timescales

NASA Astrophysics Data System (ADS)

Bertrand, T.; Forget, F.; Umurhan, O. M.; Grundy, W. M.; Schmitt, B.; Protopapa, S.; Zangari, A. M.; White, O. L.; Schenk, P. M.; Singer, K. N.; Stern, A.; Weaver, H. A.; Young, L. A.; Ennico, K.; Olkin, C. B.

2018-07-01

Pluto's landscape is shaped by the endless condensation and sublimation cycles of the volatile ices covering its surface. In particular, the Sputnik Planitia ice sheet, which is thought to be the main reservoir of nitrogen ice, displays a large diversity of terrains, with bright and dark plains, small pits and troughs, topographic depressions and evidences of recent and past glacial flows. Outside Sputnik Planitia, New Horizons also revealed numerous nitrogen ice deposits, in the eastern side of Tombaugh Regio and at mid-northern latitudes. These observations suggest a complex history involving volatile and glacial processes occurring on different timescales. We present numerical simulations of volatile transport on Pluto performed with a model designed to simulate the nitrogen cycle over millions of years, taking into account the changes of obliquity, solar longitude of perihelion and eccentricity as experienced by Pluto. Using this model, we first explore how the volatile and glacial activity of nitrogen within Sputnik Planitia has been impacted by the diurnal, seasonal and astronomical cycles of Pluto. Results show that the obliquity dominates the N2 cycle and that over one obliquity cycle, the latitudes of Sputnik Planitia between 25°S-30°N are dominated by N2 condensation, while the northern regions between 30°N and -50°N are dominated by N2 sublimation. We find that a net amount of 1 km of ice has sublimed at the northern edge of Sputnik Planitia during the last 2 millions of years. It must have been compensated by a viscous flow of the thick ice sheet. By comparing these results with the observed geology of Sputnik Planitia, we can relate the formation of the small pits and the brightness of the ice at the center of Sputnik Planitia to the sublimation and condensation of ice occurring at the annual timescale, while the glacial flows at its eastern edge and the erosion of the water ice mountains all around the ice sheet are instead related to the astronomical timescale. We also perform simulations including a glacial flow scheme which shows that the Sputnik Planitia ice sheet is currently at its minimum extent at the northern and southern edges. We also explore the stability of N2 ice deposits outside the latitudes and longitudes of the Sputnik Planitia basin. Results show that N2 ice is not stable at the poles but rather in the equatorial regions, in particular in depressions, where thick deposits may persist over tens of millions of years, before being trapped in Sputnik Planitia. Finally, another key result is that the minimum and maximum surface pressures obtained over the simulated millions of years remain in the range of milli-Pascals and Pascals, respectively. This suggests that Pluto never encountered conditions allowing liquid nitrogen to flow directly on its surface. Instead, we suggest that the numerous geomorphological evidences of past liquid flow observed on Pluto's surface are the result of liquid nitrogen that flowed at the base of thick ancient nitrogen glaciers, which have since disappeared.

Addressing the Compositional Variability of Acidalia Planitia Using MGS/TES: Constraints on Martian Hydroxide Mineralogy

NASA Astrophysics Data System (ADS)

Noe Dobrea, E. Z.; Bell, J. F., III

2002-03-01

We investigate the spectral variability of Acidalia Planitia using MGS/TES. Atmospheric removal is done by constraining our observations to EPF's. Preliminary analysis show variability of the 6-micron feature attributed water/OH-bearing minerals.

Sedna Planitia Left Member of a Synthetic Stereo Pair

NASA Image and Video Library

1998-06-04

This perspective view of Venus, generated by computer from NASA Magellan data and color-coded with emissivity, shows part of the lowland plains in Sedna Planitia. Circular depressions with associated fracture patterns, called coronae. http://photojournal.jpl.nasa.gov/catalog/PIA00313

Magellan Perspective View of Sedna Planitia, 45° N, 350° E

NASA Image and Video Library

1998-06-04

This perspective view of Venus, generated by computer from NASA Magellan data and color-coded with emissivity, shows part of Sedna Planitia and illustrates a common phenomenon of the lowland plains of Venus. http://photojournal.jpl.nasa.gov/catalog/PIA00306

Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto.

PubMed

Nimmo, F; Hamilton, D P; McKinnon, W B; Schenk, P M; Binzel, R P; Bierson, C J; Beyer, R A; Moore, J M; Stern, S A; Weaver, H A; Olkin, C B; Young, L A; Smith, K E

2016-12-01

The deep nitrogen-covered basin on Pluto, informally named Sputnik Planitia, is located very close to the longitude of Pluto's tidal axis and may be an impact feature, by analogy with other large basins in the Solar System. Reorientation of Sputnik Planitia arising from tidal and rotational torques can explain the basin's present-day location, but requires the feature to be a positive gravity anomaly, despite its negative topography. Here we argue that if Sputnik Planitia did indeed form as a result of an impact and if Pluto possesses a subsurface ocean, the required positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest nitrogen deposition. Without a subsurface ocean, a positive gravity anomaly requires an implausibly thick nitrogen layer (exceeding 40 kilometres). To prolong the lifetime of such a subsurface ocean to the present day and to maintain ocean uplift, a rigid, conductive water-ice shell is required. Because nitrogen deposition is latitude-dependent, nitrogen loading and reorientation may have exhibited complex feedbacks.

Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto

NASA Astrophysics Data System (ADS)

Nimmo, F.; Hamilton, D. P.; McKinnon, W. B.; Schenk, P. M.; Binzel, R. P.; Bierson, C. J.; Beyer, R. A.; Moore, J. M.; Stern, S. A.; Weaver, H. A.; Olkin, C. B.; Young, L. A.; Smith, K. E.; Moore, J. M.; McKinnon, W. B.; Spencer, J. R.; Beyer, R.; Binzel, R. P.; Buie, M.; Buratti, B.; Cheng, A.; Cruikshank, D.; Ore, C. Dalle; Earle, A.; Gladstone, R.; Grundy, W.; Howard, A. D.; Lauer, T.; Linscott, I.; Nimmo, F.; Parker, J.; Porter, S.; Reitsema, H.; Reuter, D.; Roberts, J. H.; Robbins, S.; Schenk, P. M.; Showalter, M.; Singer, K.; Strobel, D.; Summers, M.; Tyler, L.; White, O. L.; Umurhan, O. M.; Banks, M.; Barnouin, O.; Bray, V.; Carcich, B.; Chaikin, A.; Chavez, C.; Conrad, C.; Hamilton, D. P.; Howett, C.; Hofgartner, J.; Kammer, J.; Lisse, C.; Marcotte, A.; Parker, A.; Retherford, K.; Saina, M.; Runyon, K.; Schindhelm, E.; Stansberry, J.; Steffl, A.; Stryk, T.; Throop, H.; Tsang, C.; Verbiscer, A.; Winters, H.; Zangari, A.; Stern, S. A.; Weaver, H. A.; Olkin, C. B.; Young, L. A.; Smith, K. E.

2016-12-01

The deep nitrogen-covered basin on Pluto, informally named Sputnik Planitia, is located very close to the longitude of Pluto’s tidal axis and may be an impact feature, by analogy with other large basins in the Solar System. Reorientation of Sputnik Planitia arising from tidal and rotational torques can explain the basin’s present-day location, but requires the feature to be a positive gravity anomaly, despite its negative topography. Here we argue that if Sputnik Planitia did indeed form as a result of an impact and if Pluto possesses a subsurface ocean, the required positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest nitrogen deposition. Without a subsurface ocean, a positive gravity anomaly requires an implausibly thick nitrogen layer (exceeding 40 kilometres). To prolong the lifetime of such a subsurface ocean to the present day and to maintain ocean uplift, a rigid, conductive water-ice shell is required. Because nitrogen deposition is latitude-dependent, nitrogen loading and reorientation may have exhibited complex feedbacks.

Student Politics in Italy: From Utopia to Terrorism.

ERIC Educational Resources Information Center

Statera, Gianni

1979-01-01

The Italian student movement's move from libertarian utopia to political terrorism is analyzed in terms of the social and economic crisis in Italy. This is characterized by the collapse of representative student institutions, the rise of dogmatism and sectarianism, and the glorification of violence as a means of social change. (JMF)

The Utopia of Science Education

ERIC Educational Resources Information Center

Castano, Carolina

2012-01-01

In this forum I expand on the ideas I initially presented in "Extending the purposes of science education: addressing violence within socio-economic disadvantaged communities" by responding to the comments provided by Matthew Weinstein, Francis Broadway and Sheri Leafgren. Focusing on their notion of utopias and superheroes, I ask us to reconsider…

Crustal structure of Mars from gravity and topography

NASA Technical Reports Server (NTRS)

Neumann, G. A.; Zuber, M. T.; Wieczorek, M. A.; McGovern, P. J.; Lemoine, F. G.; Smith, D. E.

2004-01-01

Mars Orbiter Laser Altimeter (MOLA) topography and gravity models from 5 years of Mars Global Surveyor (MGS) spacecraft tracking provide a window into the structure of the Martian crust and upper mantle. We apply a finite-amplitude terrain correction assuming uniform crustal density and additional corrections for the anomalous densities of the polar caps, the major volcanos, and the hydrostatic flattening of the core. A nonlinear inversion for Moho relief yields a crustal thickness model that obeys a plausible power law and resolves features as small as 300 km wavelength. On the basis of petrological and geophysical constraints, we invoke a mantle density contrast of 600 kg m-3; with this assumption, the Isidis and Hellas gravity anomalies constrain the global mean crustal thickness to be >45 km. The crust is characterized by a degree 1 structure that is several times larger than any higher degree harmonic component, representing the geophysical manifestation of the planet's hemispheric dichotomy. It corresponds to a distinction between modal crustal thicknesses of 32 km and 58 km in the northern and southern hemispheres, respectively. The Tharsis rise and Hellas annulus represent the strongest components in the degree 2 crustal thickness structure. A uniform highland crustal thickness suggests a single mechanism for its formation, with subsequent modification by the Hellas impact, erosion, and the volcanic construction of Tharsis. The largest surviving lowland impact, Utopia, post-dated formation of the crustal dichotomy. Its crustal structure is preserved, making it unlikely that the northern crust was subsequently thinned by internal processes.

Advance Inspection of NASA Next Mars Landing Site

NASA Image and Video Library

2017-03-29

This map shows footprints of images taken from Mars orbit by the High Resolution Imaging Science Experiment (HiRISE) camera as part of advance analysis of the area where NASA's InSight mission will land in 2018. The final planned image of the set is targeted to fill in the yellow-outlined rectangle on March 30, 2017. HiRISE is one of six science instruments on NASA's Mars Reconnaissance Orbiter, which reached Mars in 2006 and surpassed 50,000 orbits on March 27, 2017. The map covers an area about 100 miles (160 kilometers) across. HiRISE has been used since 2006 to inspect dozens of candidate landing sites on Mars, including the sites where the Phoenix and Curiosity missions landed in 2008 and 2012. The site selected for InSight's Nov. 26, 2018, landing is on a flat plain in the Elysium Planitia region of Mars, between 4 and 5 degrees north of the equator. HiRISE images are detailed enough to reveal individual boulders big enough to be a landing hazard. The March 30 observation that completes the planned advance imaging of this landing area brings the number of HiRISE images of the area to 73. Some are pairs covering the same ground. Overlapping observations provide stereoscopic, 3-D information for evaluating characteristics such as slopes. On this map, coverage by stereo pairs is coded in pale blue, compared to the gray-green of single HiRISE image footprints. The ellipses on the map are about 81 miles (130 kilometers) west-to-east by about 17 miles (27 kilometers) north-to-south. InSight has about 99 percent odds of landing within the ellipse for which it is targeted. The three ellipses indicate landing expectations for three of the possible InSight launch dates: white outline for launch at the start of the launch period, on May 5, 2018; blue for launch on May 26, 2018; orange for launch on June 8, 2018. InSight -- an acronym for "Interior Exploration using Seismic Investigations, Geodesy and Heat Transport" -- will study the deep interior of Mars to improve understanding about how rocky planets like Earth formed and evolved. http://photojournal.jpl.nasa.gov/catalog/PIA21489

Geologic map of the northern plains of Mars

USGS Publications Warehouse

Tanaka, Kenneth L.; Skinner, James A.; Hare, Trent M.

2005-01-01

The northern plains of Mars cover nearly a third of the planet and constitute the planet's broadest region of lowlands. Apparently formed early in Mars' history, the northern lowlands served as a repository both for sediments shed from the adjacent ancient highlands and for volcanic flows and deposits from sources within and near the lowlands. Geomorphic evidence for extensive tectonic deformation and reworking of surface materials through release of volatiles occurs throughout the northern plains. In the polar region, Planum Boreum contains evidence for the accumulation of ice and dust, and surrounding dune fields suggest widespread aeolian transport and erosion. The most recent regional- and global-scale maps describing the geology of the northern plains are largely based on Viking Orbiter image data (Dial, 1984; Witbeck and Underwood, 1984; Scott and Tanaka, 1986; Greeley and Guest, 1987; Tanaka and Scott, 1987; Tanaka and others, 1992a; Rotto and Tanaka, 1995; Crumpler and others, 2001; McGill, 2002). These maps reveal highland, plains, volcanic, and polar units based on morphologic character, albedo, and relative ages using local stratigraphic relations and crater counts. This geologic map of the northern plains is the first published map that covers a significant part of Mars using topography and image data from both the Mars Global Surveyor and Mars Odyssey missions. The new data provide a fresh perspective on the geology of the region that reveals many previously unrecognizable units, features, and temporal relations. In addition, we adapted and instituted terrestrial mapping methods and stratigraphic conventions that we think result in a clearer and more objective map. We focus on mapping with the intent of reconstructing the history of geologic activity within the northern plains, including deposition, volcanism, erosion, tectonism, impact cratering, and other processes with the aid of comprehensive crater-density determinations. Mapped areas include all plains regions within the northern hemisphere of Mars, as well as an approximately 300-km-wide strip of cratered highland and volcanic regions, which border the plains. Note that not all of the contiguous northern plains are mapped, because some minor parts of Elysium and Amazonis Planitiae lie south of the equator.

Investigating Mars: Kaiser Crater Dunes

NASA Image and Video Library

2018-02-01

This VIS image of the floor of Kaiser Crater contains several sand dune shapes and sizes. The "whiter" material is the hard crater floor surface. Kaiser Crater is located in the southern hemisphere in the Noachis region west of Hellas Planitia. Kaiser Crater is just one of several large craters with extensive dune fields on the crater floor. Other nearby dune filled craters are Proctor, Russell, and Rabe. Kaiser Crater is 207 km (129 miles) in diameter. The dunes are located in the southern part of the crater floor. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 39910 Latitude: -46.9063 Longitude: 19.8112 Instrument: VIS Captured: 2010-12-13 11:17 https://photojournal.jpl.nasa.gov/catalog/PIA22264

The utopia of science education

NASA Astrophysics Data System (ADS)

Castano, Carolina

2012-09-01

In this forum I expand on the ideas I initially presented in "Extending the purposes of science education: addressing violence within socio-economic disadvantaged communities" by responding to the comments provided by Matthew Weinstein, Francis Broadway and Sheri Leafgren. Focusing on their notion of utopias and superheroes, I ask us to reconsider science as inevitably violent. Utopia is a concept that contributes to articulating our ideals, and serves to give us perspective on how our current reality differs from our goals. I suggest that by recognising alternative views of nature, science and "superheroes" we could see a science that is committed to the lives and struggles of students as well as the lives and struggles of other animals.

Movement as utopia.

PubMed

Couton, Philippe; López, José Julián

2009-10-01

Opposition to utopianism on ontological and political grounds has seemingly relegated it to a potentially dangerous form of antiquated idealism. This conclusion is based on a restrictive view of utopia as excessively ordered panoptic discursive constructions. This overlooks the fact that, from its inception, movement has been central to the utopian tradition. The power of utopianism indeed resides in its ability to instantiate the tension between movement and place that has marked social transformations in the modern era. This tension continues in contemporary discussions of movement-based social processes, particularly international migration and related identity formations, such as open borders transnationalism and cosmopolitanism. Understood as such, utopia remains an ongoing and powerful, albeit problematic instrument of social and political imagination.

Martian plate tectonics

NASA Astrophysics Data System (ADS)

Sleep, N. H.

1994-03-01

The northern lowlands of Mars have been produced by plate tectonics. Preexisting old thick highland crust was subducted, while seafloor spreading produced thin lowland crust during late Noachian and Early Hesperian time. In the preferred reconstruction, a breakup margin extended north of Cimmeria Terra between Daedalia Planum and Isidis Planitia where the highland-lowland transition is relatively simple. South dipping subduction occured beneath Arabia Terra and east dipping subduction beneath Tharsis Montes and Tempe Terra. Lineations associated with Gordii Dorsum are attributed to ridge-parallel structures, while Phelegra Montes and Scandia Colles are interpreted as transfer-parallel structures or ridge-fault-fault triple junction tracks. Other than for these few features, there is little topographic roughness in the lowlands. Seafloor spreading, if it occurred, must have been relatively rapid. Quantitative estimates of spreading rate are obtained by considering the physics of seafloor spreading in the lower (approx. 0.4 g) gravity of Mars, the absence of vertical scarps from age differences across fracture zones, and the smooth axial topography. Crustal thickness at a given potential temperature in the mantle source region scales inversely with gravity. Thus, the velocity of the rough-smooth transition for axial topography also scales inversely with gravity. Plate reorganizations where young crust becomes difficult to subduct are another constraint on spreading age. Plate tectonics, if it occurred, dominated the thermal and stress history of the planet. A geochemical implication is that the lower gravity of Mars allows deeper hydrothermal circulation through cracks and hence more hydration of oceanic crust so that more water is easily subducted than on the Earth. Age and structural relationships from photogeology as well as median wavelength gravity anomalies across the now dead breakup and subduction margins are the data most likely to test and modify hypotheses about Mars plate tectonics.

Towards Real Utopias in Higher Education

ERIC Educational Resources Information Center

Suoranta, Juha; FitzSimmons, Robert

2017-01-01

In this article we search for real utopias for higher education by first introducing and describing a vital counter-hegemonic students movement of the early 1960s--Students for a Democratic Society (SDS), and their Port Huron Statement (1962). The movement maintained that universities are not communities of equals but served the elite. In the…

Geologic Map of the Lavinia Planitia Quadrangle (V-55), Venus

USGS Publications Warehouse

Ivanov, Mikhail A.; Head, James W.

2001-01-01

Introduction The Lavinia Planitia quadrangle (V-55) is in the southern hemisphere of Venus and extends from 25 to 50 south latitude and from 330 to 360 longitude. It covers the central and northern part of Lavinia Planitia and parts of its margins. Lavinia Planitia consists of a centralized, deformed lowland flooded by volcanic deposits and surrounded by Dione Regio to the west (Keddie and Head, 1995), Alpha Regio tessera (Bindschadler and others, 1992a) and Eve Corona (Stofan and others, 1992) to the northeast, itself an extensive rift zone and coronae belt to the east and south (Baer and others, 1994; Magee and Head, 1995), Mylitta Fluctus to the south (Magee Roberts and others, 1992), and Helen Planitia to the southwest (Senske and others, 1991). In contrast to other areas on Venus, the Lavinia Planitia area is one of several large, relatively equidimensional lowlands (basins) and as such is an important region for the analysis of processes of basin formation and volcanic flooding. Before the Magellan mission, Lavinia Planitia was known on the basis of Pioneer-Venus altimetry to be a lowland area (Pettengill and others, 1980);. Arecibo radar images showed that Lavinia Plaitia was surrounded by several corona-like features and rift-like fractures parallel to the basin margin to the east and south (Senske and others, 1991; Campbell and others, 1990). Arecibo data further revealed that the interior contained complex patterns of deformational features in the form of belts and volcanic plains, and several regions along the margins were seen to be the sources of extensive outpourings of digitate lava flows into the interior (Senske and others, 1991; Campbell and others, 1990). Early Magellan results showed that the ridge belts are composed of complex structures of both extensional and contractional origin (Squyres and others, 1992; Solomon and others, 1992) and that the complex lava flows (fluctus) along the margins (Magee Roberts and others, 1992) emanated from a variety of sources ranging from volcanoes to coronae (Magee and Head, 1995; Keddie and Head, 1995). In addition, global analysis of the distribution of volcanic features revealed that Lavinia Planitia is an area deficient in the distribution of distinctive volcanic sources and corona-like features (Head and others, 1992; Crumpler and others, 1993). Lavinia Planitia gravity and geoid data show that the lowland is characterized by a -30 mGal gravity anomaly and a -10 m geoid anomaly, centered on eastern Lavinia (Bindschadler and others, 1992b; Konopliv and Sjogren, 1994). Indeed, the characteristics and configuration of Lavinia Planitia have been cited as evidence for the region being the site of large-scale mantle down welling (Bindschadler and others, 1992b). Thus, this region is a laboratory for the study of the formation of lowlands, the emplacement of volcanic plains, the formation of associated tectonic features, and their relation to mantle processes. These questions and issues are the basis for our geologic mapping analysis. In our analysis we have focused on the geologic mapping of the Lavinia Planitia quadrangle using traditional methods of geologic unit definition and characterization for the Earth (for example, American Commission on Stratigraphic Nomenclature, 1961) and planets (for example, Wilhelms, 1990) appropriately modified for radar data (Tanaka, 1994). We defined units and mapped key relations using the full resolution Magellan synthetic aperture radar (SAR) data (mosaiced full resolution basic image data records, C1-MIDR's, F-MIDR's, and F-Maps) and transferred these results to the base map compiled at a scale of 1:5 million. In addition to the SAR image data, we incorporated into our analyses digital versions of Magellan altimetry, emissivity, Fresnel reflectivity, and roughness data (root mean square, rms, slope). The background for our unit definition and characterization is described in Tanaka (1994), Basilevsky and Head (1995a, b)

The Viking gas exchange experiment results from Chryse and Utopia surface samples

NASA Technical Reports Server (NTRS)

Oyama, V. I.; Berdahl, B. J.

1977-01-01

Immediate gas changes occurred when untreated Martian surface samples were humidified and/or wet by an aqueous nutrient medium in the Viking lander gas exchange experiment. The evolutions of N2, CO2, and Ar are mainly associated with soil surface desorption caused by water vapor, while O2 evolution is primarily associated with decomposition of superoxides inferred to be present on Mars. On recharges with fresh nutrient and test gas, only CO2 was given off, and its rate of evolution decreased with each recharge. This CO2 evolution is thought to come from the oxidation of organics present in the nutrient by gamma Fe2O3 in the surface samples. Atmospheric analyses were also performed at both sites. The mean atmospheric composition from four analyses is N2, 2.3%; O2, not greater than 0.15%; Ar, 1.5% and CO2, 96.2%.

Methane Seepage on Mars: Where to Look and Why

PubMed Central

Etiope, Giuseppe

2017-01-01

Abstract Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as “gas seepage.” Here, we review the variety of subsurface processes that could result in methane seepage on Mars. Such methane could originate from abiotic chemical reactions, thermogenic alteration of abiotic or biotic organic matter, and ancient or extant microbial metabolism. These processes can occur over a wide range of temperatures, in both sedimentary and igneous rocks, and together they enhance the possibility that significant amounts of methane could have formed on early Mars. Methane seepage to the surface would occur preferentially along faults and fractures, through focused macro-seeps and/or diffuse microseepage exhalations. Our work highlights the types of features on Mars that could be associated with methane release, including mud-volcano-like mounds in Acidalia or Utopia; proposed ancient springs in Gusev Crater, Arabia Terra, and Valles Marineris; and rims of large impact craters. These could have been locations of past macro-seeps and may still emit methane today. Microseepage could occur through faults along the dichotomy or fractures such as those at Nili Fossae, Cerberus Fossae, the Argyre impact, and those produced in serpentinized rocks. Martian microseepage would be extremely difficult to detect remotely yet could constitute a significant gas source. We emphasize that the most definitive detection of methane seepage from different release candidates would be best provided by measurements performed in the ground or at the ground-atmosphere interface by landers or rovers and that the technology for such detection is currently available. Key Words: Mars—Methane—Seepage—Clathrate—Fischer-Tropsch—Serpentinization. Astrobiology 17, 1233–1264. PMID:28771029

Evidence for a Large Natural Nuclear Reactor in Mars Past

NASA Astrophysics Data System (ADS)

Brandenburg, J. E.

2006-05-01

It has long been known that The isotopic ratios 129 Xe/132Xe and 40Ar/36Ar are very high in Mars atmosphere relative to Earth or meteoritic backgrounds. This fact has allowed the SNC meteorites to be identified as Martian based on their trapped gases (1). However, while the isotopic anomalies explained one mystery, the origin of the SNC meteorites, they created a new mystery: the rock samples from Mars show no evidence of the large amounts of Iodine or Potassium that would give naturally give rise to the Xenon and Argon isotopic anomalies (2). In fact, the Martian meteorites are depleted in Potassium relative to earth rocks. This is added to the fact that for other isotopic systems such as 80Kr, Mars rock samples must be irradiated by neutrons at fluences of 1015 /cm2 to explain observed abundances (1) . Compounding the mystery is the fact that Mars surface layer has elevated levels of Uranium and Thorium relative to Earth and even its own rocks, as determined from SNCs (3). These anomalies can be explained if some large nuclear energy release, such as by natural nuclear reactors known to have operated on Earth (4) in in some concentrated ore body, occurred with perhaps a large volcano like explosion that spread residues over the planets surface. Based on gamma ray observations from orbit (3), and the correlations of normally uncorrelated Th and K deposits , the approximate location of this event would appear to have been in the north of Mars in a region in Acidalia Planitia centered at 45N Latitude and 15W Longitude (5). The possibility of such a large radiological event in Mars past adds impetus to Mars exploration efforts and particularly to a human mission to Mars to learn more about this possible occurrence. (1) Swindle, T. D. , Caffee, M. W., and Hohenberg, C. M., (1986) "Xenon and other Noble Gases in Shergottites" Geochimica et Cosmochimica Acta, 50, pp 1001-1015. (2) Banin, A., Clark, B.C., and Wanke, H. "Surface Chemistry and Mineralogy" (1992) in "Mars" Kieffer , H.H. , Jackosky, B. M. , Snyder C.W. , and Matthews , M.S. Editors , The University of Arizona Press, (3) Taylor G. Jeffery, et al. "Igneous and Aqueous Processes on Mars: Evidence From Measurements of K and Th by the Mars Odyssey Gamma Ray Spectrometer." (2003) Proc. 6th International Mars Conference. Pasadena Ca. (4) Meshik , A. P. "the Workings of An Ancient Nuclear Reactor" Scientific American, November 2005, p83. (5) Brandenburg, J.E., "Evidence for a large Natural Nuclear Reactor in Mars Past " Proceedings of the Space technology International Forum Albuquereque NM Feb 12-16 2006.

Arcadia Planitia Hills

NASA Image and Video Library

2018-04-25

The rounded hills in this VIS image are located in Arcadia Planitia. Broad linear ridges and groups of hills in this region are part of Phlegra Dorsa (ridges) and Phlegra Montes (hills). Orbit Number: 71248 Latitude: 30.6712 Longitude: 171.018 Instrument: VIS Captured: 2018-01-05 17:05 https://photojournal.jpl.nasa.gov/catalog/PIA22377

Geologic Mapping of the Guinevere Planitia Quadrangle of Venus

NASA Technical Reports Server (NTRS)

Crown, David A.; Stofan, Ellen R.; Bleamaster, Leslie F., III

2008-01-01

The Guinevere Planitia quadrangle of Venus (0-25degN, 300-330deg) covers a lowland region east of Beta Regio and west of Eistla Regio, including parts of Guinevere and Undine Planitiae. The V-30 quadrangle is dominated by low-lying plains interpreted to be of volcanic origin and exhibiting numerous wrinkle ridges. Using Pioneer Venus, Goldstone, and Arecibo data, previous investigators have described radar bright, dark, and mottled plains units in the Guinevere Planitia region, as well as arcuate fracture zones and lineament belt segments that define the Beta-Eistla deformation zone [1-5]. Magellan SAR images show that volcanic landforms compose the majority of the surface units in V-30 [6-7]. The quadrangle contains parts of four major volcanoes: Atanua (9degN, 307deg), Rhpisunt (3degN, 302deg), Tuli (13degN, 314deg), and Var (3degN, 316deg) Montes, and three coronae: Hulda (12degN, 308deg), Madderakka (9degN, 316deg), and Poloznitsa (1degN, 303deg). Seymour crater, located at 18degN, 327deg, is associated with extensive crater outflow deposits.

Dreaming of a Better Life: Utopia as a Focus for Thematic, Interdisciplinary Instruction

ERIC Educational Resources Information Center

Resor, Cynthia; Gandy, S. Kay

2014-01-01

Throughout history humans have dreamed of a better life. This concept of utopia can be used as a central focus for thematic and interdisciplinary instruction. This approach has three key advantages. First, students recognize that certain themes are consistent across time and place and that realization can lead students to explore their own dreams…

Needing "Tomorrow as Fish Need Water": Dystopia, Utopia, and Freire's Pedagogy

ERIC Educational Resources Information Center

Papastephanou, Marianna

2016-01-01

In this article, I discuss the philosophical-educational attention to Freire's utopian pedagogy of the future and I argue that equal attention should be due to Freire's dystopian account of the present. To this end, Freire's utopia and dystopia are associated with the interplay of his notions of annunciation and denunciation. The role of dystopian…

Beyond Rural Idylls: Imperfect Lesbian Utopias at Michigan Womyn's Music Festival

ERIC Educational Resources Information Center

Browne, Kath

2011-01-01

Whilst rural idylls have dominated some discussions of rural social difference, little attention has been paid to rural utopias. Imagined, material and discursive experiences of utopian rural ideals are critically examined in this paper. It takes as its focus the Michigan Womyn's Music Festival--an annual US womyn-only festival--in order to…

Deaf Utopias? Reviewing the Sociocultural Literature on the World's "Martha's Vineyard Situations"

ERIC Educational Resources Information Center

Kusters, Annelies

2010-01-01

Martha's Vineyard--an island off the East Coast of the United States--is known as a community where "everyone signed" for several hundred years, a utopia in the eyes of many Deaf people. Currently, there exist around the world a number of small similar "shared signing communities," for example, in Mexico, Bali, Israel, and…

Reorientation and faulting of Pluto due to volatile loading within Sputnik Planitia

NASA Astrophysics Data System (ADS)

Keane, James T.; Matsuyama, Isamu; Kamata, Shunichi; Steckloff, Jordan K.

2016-12-01

Pluto is an astoundingly diverse, geologically dynamic world. The dominant feature is Sputnik Planitia—a tear-drop-shaped topographic depression approximately 1,000 kilometres in diameter possibly representing an ancient impact basin. The interior of Sputnik Planitia is characterized by a smooth, craterless plain three to four kilometres beneath the surrounding rugged uplands, and represents the surface of a massive unit of actively convecting volatile ices (N2, CH4 and CO) several kilometres thick. This large feature is very near the Pluto-Charon tidal axis. Here we report that the location of Sputnik Planitia is the natural consequence of the sequestration of volatile ices within the basin and the resulting reorientation (true polar wander) of Pluto. Loading of volatile ices within a basin the size of Sputnik Planitia can substantially alter Pluto’s inertia tensor, resulting in a reorientation of the dwarf planet of around 60 degrees with respect to the rotational and tidal axes. The combination of this reorientation, loading and global expansion due to the freezing of a possible subsurface ocean generates stresses within the planet’s lithosphere, resulting in a global network of extensional faults that closely replicate the observed fault networks on Pluto. Sputnik Planitia probably formed northwest of its present location, and was loaded with volatiles over million-year timescales as a result of volatile transport cycles on Pluto. Pluto’s past, present and future orientation is controlled by feedbacks between volatile sublimation and condensation, changing insolation conditions and Pluto’s interior structure.

Remote sensing evidence of lava-ground ice interactions associated with the Lost Jim Lava Flow, Seward Peninsula, Alaska

NASA Astrophysics Data System (ADS)

Marcucci, Emma C.; Hamilton, Christopher W.; Herrick, Robert R.

2017-12-01

Thermokarst terrains develop when ice-bearing permafrost melts and causes the overlying surface to subside or collapse. This process occurs widely throughout Arctic regions due to environmental and climatological factors, but can also be induced by localized melting of ground ice by active lava flows. The Lost Jim Lava Flow (LJLF) on the Seward Peninsula of Alaska provides evidence of former lava-ground ice interactions. Associated geomorphic features, on the scale of meters to tens of meters, were identified using satellite orthoimages and stereo-derived digital terrain models. The flow exhibits positive- and mixed-relief features, including tumuli ( N = 26) and shatter rings ( N = 4), as well as negative-relief features, such as lava tube skylights ( N = 100) and irregularly shaped topographic depressions ( N = 1188) that are interpreted to include lava-rise pits and lava-induced thermokarst terrain. Along the margins of the flow, there are also clusters of small peripheral pits that may be the products of meltwater or steam escape. On Mars, we observed morphologically similar pits near lava flow margins in northeastern Elysium Planitia, which suggests a common formation mechanism. Investigating the LJLF may therefore help to elucidate processes of lava-ground ice interaction on both Earth and Mars.

Observations at the Mars Pathfinder site: Do they provide "unequivocal" evidence of catastrophic flooding?

USGS Publications Warehouse

Chapman, M.G.; Kargel, J.S.

1999-01-01

After Mars Pathfinder landed at the mouth of Ares Vallis, a large channel that drains into the Chryse Planitia basin, the mission reports unanimously supported the interpretation that the lander site is the locus of catastrophic flooding by noting that all aspects of the scene are consistent with this interpretation. However, alternatives cannot be ruled out by any site observations, as all aspects of the scene are equally consistent with other interpretations of origin, namely, ice and mass-flow processes subsequently modified by wind erosion. The authors discuss alternative explanations for the geologic history of the channel based on a regional view of the circum-Chryse channels from Viking images (our best broad-scale information to date) and the local view from the recent Pathfinder landing site. Mega-indicators of channel origin, the regional geomorphology, geology, and planetary climatic conditions, taken together suggest some combination of flood, mass flow, glacial, and eolian processes. The macro-indicators of channel origin (sedimentologic) are also not indicative of one process of emplacement, either as single criteria or taken cumulatively. Finally, the micro-indicators of channel origin (geochemical and mineralogic composition) do not provide very tight constraints on the deposits' possible origins other than that water was in some way involved.

Giant Icebergs and Biological Productivity on Early Mars

NASA Astrophysics Data System (ADS)

Uceda, E.; Fairen, A. G.; Woodworth-Lynas, C.

2016-12-01

We have previously presented evidence for furrows, dump structures and chains of craters that we interpret as indication for giant iceberg transport and grounding on very cold oceans on early Mars, both in the northern plains and in the Hellas basin. Structures include: 1. Furrows: The furrows are located in elevated areas or on local topographic highs, particularly on the Hellas basin. We interpret these features in terms of iceberg rafting and grounding. 2. Chains of craters: High-resolution images of Utopia and Isidis Basins reveal chains of crater-like structures several hundred meters wide and 1 to 5 km long. 3. Dump structures: Dark boulder clusters are revealed at large scales by their slightly darker tonality with respect to the surrounding terrain. These clusters have sizes ranging from several hundred meters to 1-2 km. On Earth's oceans, giant icebergs release melting water containing nanoparticulate iron and other micronutrients, which support biological metabolism and growth to the near-coastal euphotic ecosystems, many of which are iron limited. This iron limitation of primary producers has been documented in large regions of the Earth's oceans, most notably in polar areas proximal to significant glacial activity, and is counterbalanced by the substantial enrichment of terrigenous material supplied by icebergs. The biological productivity extends hundreds of kilometres from the giant icebergs, and persists for over one month after the iceberg passes. Here we propose that giant iceberg activity on early Mars could have promoted a similar enhancing of biological productivity on the planet's oceans. The identification of specific biosignatures in icebergs trails on Earth could give clues as to what kind of biosignatures could be expected on the ancient Mars ocean floors, and where to look for them. In particular, assuming that life existed on Mars coeval to glacial activity, enhanced concentrations of organic carbon could be anticipated near giant iceberg trails, analogous to what is observed in polar oceans on Earth. Acknowledgements: The research leading to these results is a contribution from the Project "icyMARS", funded by the European Research Council, Starting Grant no 307496.

Mud Volcanoes - Analogs to Martian Cones and Domes (by the Thousands!)

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Oehler, Dorothy

2010-01-01

Mud volcanoes are mounds formed by low temperature slurries of gas, liquid, sediments and rock that erupt to the surface from depths of meters to kilometers. They are common on Earth, with estimates of thousands onshore and tens of thousands offshore. Mud volcanoes occur in basins with rapidly-deposited accumulations of fine-grained sediments. Such settings are ideal for concentration and preservation of organic materials, and mud volcanoes typically occur in sedimentary basins that are rich in organic biosignatures. Domes and cones, cited as possible mud volcanoes by previous authors, are common on the northern plains of Mars. Our analysis of selected regions in southern Acidalia Planitia has revealed over 18,000 such features, and we estimate that more than 40,000 occur across the area. These domes and cones strongly resemble terrestrial mud volcanoes in size, shape, morphology, associated flow structures and geologic setting. Geologic and mineralogic arguments rule out alternative formation mechanisms involving lava, ice and impacts. We are studying terrestrial mud volcanoes from onshore and submarine locations. The largest concentration of onshore features is in Azerbaijan, near the western edge of the Caspian Sea. These features are typically hundreds of meters to several kilometers in diameter, and tens to hundreds of meters in height. Satellite images show spatial densities of 20 to 40 eruptive centers per 1000 square km. Many of the features remain active, and fresh mud flows as long as several kilometers are common. A large field of submarine mud volcanoes is located in the Gulf of Cadiz, off the Atlantic coasts of Morocco and Spain. High-resolution sonar bathymetry reveals numerous km-scale mud volcanoes, hundreds of meters in height. Seismic profiles demonstrate that the mud erupts from depths of several hundred meters. These submarine mud volcanoes are the closest morphologic analogs yet found to the features in Acidalia Planitia. We are also conducting laboratory analyses of surface samples collected from mud volcanoes in Azerbaijan, Taiwan and Japan. X-ray diffraction, visible / near infrared reflectance spectroscopy and Raman spectroscopy show that the samples are dominated by mixed-layer smectite clays, along with quartz, calcite and pyrite. Thin section analysis by optical and scanning electron microscopy confirms the mineral identifications. These samples also contain chemical and morphological biosignatures, including common microfossils, with evidence of partial replacement by pyrite. The bulk samples contain approximately 1 wt% total organic carbon and 0.4 mg / gm volatile hydrocarbons. The thousands of features in Acidalia Planitia cited as analogous to terrestrial mud volcanoes clearly represent an important element in the sedimentary record of Mars. Their location, in the distal depocenter for massive Hesperian-age floods, suggests that they contain fine-grained sediments from a large catchment area in the martian highlands. We have proposed these features as a new class of exploration target that can provide access to minimally-altered material from significant depth. By analogy to terrestrial mud volcanoes, these features may also be excellent sites for the sampling martian organics and subsurface microbial life, if such exist or ever existed.

Technology, Utopia and Scholarly Life: Ideals and Realities in the Work of Hermann Hesse

ERIC Educational Resources Information Center

Roberts, Peter

2009-01-01

This article considers the relationship between technology, utopia and scholarly life in Hermann Hesse's novel, "The Glass Bead Game." In the first part of Hesse's book, the Glass Bead Game and the society of which it is a part, Castalia, are portrayed in idealistic terms. The second part of the novel chronicles the educational life of Joseph…

Pitted cones and domes on Mars: Observations in Acidalia Planitia and Cydonia Mensae using MOC, THEMIS, and TES data

USGS Publications Warehouse

Farrand, W. H.; Gaddis, L.R.; Keszthelyi, L.

2005-01-01

Domes and cones with summit pits located in Acidalia Planitia and Cydonia Mensae were studied using MOC and THEMIS images and a TES-derived thermal inertia map. North of 40.5??N latitude, the features have a dome-like morphology, and south of that latitude, the morphology is more cone-like. Layering is apparent in the summit craters of fresher looking southern cones, and asymmetric aprons were observed in some instances. Some of the northern domes also display layering in their summit craters, but asymmetric aprons were not observed. The northern domes can also display multiple summit pits or no summit pits at all and can occur in association with higher-albedo "pancake" features. The northern domes are higher in albedo but have apparent thermal inertias that are lower than the surrounding plains. The apparent thermal inertia values of the southern cones range from values comparable to the surrounding plains to slightly lower. From the TES thermal inertia map, we infer that the thermal inertia values of the pitted cones are between those of basaltic fine dust and sand, while those of the surrounding plains are closer to that of basaltic sand. While a unique interpretation of the origin of the pitted cones is not possible with the available data, we do not find compelling evidence to suggest an origin related to either basaltic volcanism or ground-ice. Instead, an origin for these features through some combination of mud volcanism and evaporite deposition around geysers and/or springs is most consistent with the observations. Copyright 2005 by the American Geophysical Union.

Acidalia Planitia

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site] (Released 25 July 2002) The lineations seen in this THEMIS visible image occur in Acidalia Planitia, and create what is referred to as 'patterned ground' or 'polygonal terrain.' The lineations are fissures, or cracks in the ground and are possibly evidence that there was once subsurface ice or water in the region. On Earth, similar features occur when ice or water is removed from the subsurface. The removal of material causes the ground to slump, and the surface expression of this slumping is the presence of these fissures, which tend to align themselves along common orientations, and in some cases, into polygonal shapes. There are other hypotheses, not all of which involve liquid or frozen water, regarding the formation of patterned ground. Desiccation of wet soils on Earth forms mud cracks, which are similar in appearance to the martian features, but occur on a much smaller scale. Alternatively, oriented cracks form when lava flows cool. The cracks formed by this process would be on about the same scale as those seen in this image. The best example of polygonal terrain occurs about halfway down the image. The largest fractures, as in other places in the image, run from the lower left to the upper right of the image. In some cases, though, smaller fractures occur in other orientations, creating the polygonal terrain. Scientists have been aware of these features on the surface of Mars since the Viking era, but the THEMIS visible camera will allow scientists to map these features at higher resolution with more coverage over the high latitude regions where they are most common, perhaps giving further insight into the mechanism(s) of their formation.

Summer season variability of the north residual cap of Mars as observed by the Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES)

USGS Publications Warehouse

Calvin, W.M.; Titus, T.N.

2008-01-01

Previous observations have noted the change in albedo in a number of North Pole bright outliers and in the distribution of bright ice deposits between Mariner 9, Viking, and Mars Global Surveyor (MGS) data sets. Changes over the summer season as well as between regions at the same season (Ls) in different years have been observed. We used the bolometric albedo and brightness temperature channels of the Thermal Emission Spectrometer (TES) on the MGS spacecraft to monitor north polar residual ice cap variations between Mars years and within the summer season for three northern Martian summers between July 1999 and April 2003. Large-scale brightness variations are observed in four general areas: (1) the patchy outlying frost deposits from 90 to 270??E, 75 to 80??N; (2) the large "tail" below the Chasma Boreale and its associated plateau from 315 to 45??E, 80 to 85??N, that we call the "Boreale Tongue" and in Hyperboreae Undae; (3) the troughed terrain in the region from 0 to 120??E longitude (the lower right on a polar stereographic projection) we have called "Shackleton's Grooves" and (4) the unit mapped as residual ice in Olympia Planitia. We also note two areas which seem to persist as cool and bright throughout the summer and between Mars years. One is at the "source" of Chasma Boreale (???15??E, 85??N) dubbed "McMurdo", and the "Cool and Bright Anomaly (CABA)" noted by Kieffer and Titus 2001. TES Mapping of Mars' north seasonal cap. Icarus 154, 162-180] at ???330??E, 87??N called here "Vostok". Overall defrosting occurs early in the summer as the temperatures rise and then after the peak temperatures are reached (Ls???110) higher elevations and outlier bright deposits cold trap and re-accumulate new frost. Persistent bright areas are associated with either higher elevations or higher background albedos suggesting complex feedback mechanisms including cold-trapping of frost due to albedo and elevation effects, as well as influence of mesoscale atmospheric dynamics. ?? 2007 Elsevier Ltd. All rights reserved.

Geomorphological Evidence for Excess Ice in the Southern Hemisphere of Mars

NASA Astrophysics Data System (ADS)

Viola, D.; McEwen, A. S.

2016-12-01

Abundant water ice is present in the polar caps and in the subsurface at mid to high latitudes on Mars. Subsurface ice can either be confined to regolith pore spaces (pore-filling) or "excess ice" that exceeds the available pore space. The latitudinal bounds of modern excess ice in the northern hemisphere of Mars have been constrained by observations of recent ice-exposing impacts (Dundas et al., 2014, JGR: Planets): >25 have been found as of July 2016 at latitudes above 38°N. However, new impact craters are less commonly found in the southern hemisphere since impacts into relatively dust-free surfaces are difficult to discover; only 5 ice-exposing impacts have been found, all at >55°S. Therefore, we propose the use of other surface morphological features to define the present mid-latitude excess ice boundary in the southern hemisphere. We primarily focus on "expanded craters" that show evidence for thermokarstic diameter enlargement. These craters likely form when an impact exposes a subsurface excess ice layer that subsequently sublimates, leading to an apparent widening of the crater. It is important to note that expanded craters suggest that ice was present both at the time of impact and today, since the widespread loss of an excess ice layer would lead to the collapse of these features. Expanded craters have been mapped across a broad region of the northern plains, and their distribution is consistent with the latitudinal limits of new ice-exposing craters. We also observe expanded craters in and around Hellas Planitia, and will use images from the Context Camera (CTX) on the Mars Reconnaissance Orbiter (MRO) to conduct preliminary mapping of their broader distribution across the southern hemisphere. We will also identify additional features that suggest present or past ice: scallops, polygonal patterned ground, and pedestal craters. This data will be used to infer the latitudinal limit and longitudinal variations of modern excess ice in the southern hemisphere of Mars. This has implications on the history and preservation of water ice on Mars, and may be of interest for future human exploration.

Debris-flow origin for the Simud/Tiu deposit on Mars

USGS Publications Warehouse

Tanaka, K.L.

1999-01-01

A late Hesperian smooth plains deposit on Mars interpreted as a debris flow extends more than 2000 km from Hydraotes Chaos, through Simud and Tiu Valles, and into Chryse Planitia. The Simud/Tiu deposit widens out to >1000 km and embays streamlined landforms and knobs made up of sedimentary and perhaps volcanic deposits that were carved by earlier channeling activity. Morphologic features of the Simud/Tiu deposit observed in Viking and Pathfinder images are generally consistent with a debris-flow origin, but some of the deposit's salient features are not readily explained by catastrophic flooding or ice flow. Internal depressions appear to be bounded by linear scarps along flow margins where differential shearing may have occurred and in areas where flow spreading may have produced zones of extensional breakup and thinning within the flow. Possible flow lobes within the deposit may have formed by successive flow surges within the flow unit. The Pathfinder landing site is on the Simud/Tiu deposit, and the observations there are consistent with debris flow. The low, longitudinal ridges at the site may have formed by clast interactions as the flow ground to a halt. Imbricated, planar rocks on the ridges, such as in the Rock Garden, also may have been emplaced by debris or ice flow. However, stream energy calculations at Ares Vallis and channel geology indicate that flooding probably was incapable of emplacing the meter-size boulders observed at the Pathfinder site. Dewatering of pressurized zones in the debris flow or underlying material may be responsible for mud eruptions that formed a couple of patches of low pancakelike shields up to 5 km in diameter and for probable water flows that formed two small rille channels a few kilometers long. Local irregular grooves may be cracks that resulted from later desiccation and contraction of the flow material. The debris-flow unit apparently coalesced from outflows of water-fluidized debris originating from beneath chaotic and hummocky terrains within and along the margins of Simud and Tiu Valles. The deposit is onlapped from the north by another flow deposit originating from Acidalia Planitia. If the Simud/Tiu debris flow had entered a standing body of water, a turbidity current may have arisen from the debris flow and then backflowed over the debris flow to account for the Acidalia deposit.

Valles Marineris and Chryse Outflow Channels

NASA Image and Video Library

1998-06-08

A color image of Valles Marineris, the great canyon and the south Chryse basin-Valles Marineris outflow channels of Mars; north toward top. The scene shows the entire Valles Marineris canyon system, over 3,000 km long and averaging 8 km deep, extending from Noctis Labyrinthus, the arcuate system of graben to the west, to the chaotic terrain to the east and related outflow canyons that drain toward the Chryse basin. Eos and Capri Chasmata (south to north) are two canyons connected to Valles Marineris. Ganges Chasma lies directly north. The chaos in the southeast part of the image gives rise to several outflow channels, Shalbatana, Simud, Tiu, and Ares Valles (left to right), that drained north into the Chryse basin. The mouth of Ares Valles is the site of the Mars Pathfinder lander. This image is a composite of Viking medium-resolution images in black and white and low-resolution images in color; Mercator projection. The image roughly extends from latitude 20 degrees S. to 20 degrees N. and from longitude 15 degrees to 102.5 degrees. The connected chasma or valleys of Valles Marineris may have formed from a combination of erosional collapse and structural activity. Layers of material in the eastern canyons might consist of carbonates deposited in ancient lakes, eolian deposits, or volcanic materials. Huge ancient river channels began from Valles Marineris and from adjacent canyons and ran north. Many of the channels flowed north into Chryse Basin. The south Chryse outflow channels are cut an average of 1 km into the cratered highland terrain. This terrain is about 9 km above datum near Valles Marineris and steadily decreases in elevation to 1 km below datum in the Chryse basin. Shalbatana is relatively narrow (10 km wide) but can reach 3 km in depth. The channel begins at a 2- to 3-km-deep circular depression within a large impact crater, whose floor is partly covered by chaotic material, and ends in Simud Valles. Tiu and Simud Valles consist of a complex of connected channel floors and chaotic terrain and extend as far south as and connect to eastern Valles Marineris. Ares Vallis originates from discontinuous patches of chaotic terrain within large craters. In the Chryse basin the Ares channel forks; one branch continues northwest into central Chryse Planitia and the other extends north into eastern Chryse Planitia. http://photojournal.jpl.nasa.gov/catalog/PIA00426

Constraining the Date of the Martian Dynamo Shutdown by Means of Crater Magnetization Signatures

NASA Astrophysics Data System (ADS)

Vervelidou, Foteini; Lesur, Vincent; Grott, Matthias; Morschhauser, Achim; Lillis, Robert J.

2017-11-01

Mars is believed to have possessed a dynamo that ceased operating approximately 4 Ga ago, although the exact time is still under debate. The scope of this study is to constrain the possible timing of its cessation by studying the magnetization signatures of craters. The study uses the latest available model of the lithospheric magnetic field of Mars, which is based on Mars Global Surveyor data. We tackle the problem of nonuniqueness that characterizes the inversion of magnetic field data for the magnetization by inferring only the visible part of the magnetization, that is, the part of the magnetization that gives rise to the observed magnetic field. Further on, we demonstrate that a zero visible magnetization is a valid proxy for the entire magnetization being zero under the assumption of a magnetization distribution of induced geometry. This assumption holds for craters whose thermoremanent magnetization has not been significantly altered since its acquisition. Our results show that the dynamo shut off after the impacts that created the Acidalia and SE Elysium basins and before the crust within the Utopia basin cooled below its magnetic blocking temperature. Accounting for the age uncertainties in the dating of these craters, we estimate that the dynamo shut off at an N(300) crater retention age of 2.5-3.2 or an absolute model age of 4.12-4.14 Ga. Moreover, the Martian dynamo may have been weaker in its early stage, which if true implies that the driving mechanism of the Martian dynamo was not the same throughout its history.

Geologic map of the Ganiki Planitia quadrangle (V-14), Venus

USGS Publications Warehouse

Grosfils, Eric B.; Long, Sylvan M.; Venechuk, Elizabeth M.; Hurwitz, Debra M.; Richards, Joseph W.; Drury, Dorothy E.; Hardin, Johanna

2011-01-01

The Ganiki Planitia (V-14) quadrangle on Venus, which extends from 25° N. to 50° N. and from 180° E. to 210° E., derives its name from the extensive suite of plains that dominates the geology of the northern part of the region. With a surface area of nearly 6.5 x 106 km2 (roughly two-thirds that of the United States), the quadrangle is located northwest of the Beta-Atla-Themis volcanic zone and southeast of the Atalanta Planitia lowlands, areas proposed to be the result of large scale mantle upwelling and downwelling, respectively. The region immediately south of Ganiki Planitia is dominated by Atla Regio, a major volcanic rise beneath which localized upwelling appears to be ongoing, whereas the area just to the north is dominated by the orderly system of north-trending deformation belts that characterize Vinmara Planitia. The Ganiki Planitia quadrangle thus lies at the intersection between several physiographic regions where extensive mantle flow-induced tectonic and volcanic processes are thought to have occurred. The geology of the V-14 quadrangle is characterized by a complex array of volcanic, tectonic, and impact-derived features. There are eleven impact craters with diameters from 4 to 64 km, as well as four diffuse 'splotch' features interpreted to be the product of near-surface bolide explosions. Tectonic activity has produced heavily deformed tesserae, belts of complex deformation and rifts as well as a distributed system of fractures and wrinkle ridges. Volcanic activity has produced extensive regional plains deposits, and in the northwest corner of the quadrangle these plains host the initial (or terminal) 700 km of the Baltis Vallis canali, an enigmatic volcanic feature with a net length of ~7,000 km that is the longest channel on Venus. Major volcanic centers in V-14 include eight large volcanoes and eight coronae; all but one of these sixteen features was noted during a previous global survey. The V-14 quadrangle contains an abundance of minor volcanic features including individual shield volcanoes and localized fissure eruptions as well as many small annular structures and domes, which often serve as the source for local lava flows. The topographic and geophysical characteristics of the Ganiki Planitia quadrangle are less complex than the surface geology, but they yield equally valuable information about the region’s formation and evolution. Referenced to the mean planetary radius of 6051.84 km, the average elevation in the quadrangle is -0.26±0.86 km (2σ) with a full range of -2.58 km to 1.85 km. The highest 2.5 percent of elevations in the quadrangle (above 0.60 km) are associated primarily with the major tessera blocks and the peaks of a few volcanic edifices, whereas the lowest 2.5 percent (below -1.12 km) mostly occur within corona interiors and in the northwest corner of the quadrangle where the plains begin to merge into the Atalanta Planitia lowlands. At the ~4.6 km/pixel scale of the topography data, the mean point-to-point topographic slope is 0.63° and topographic slopes greater than 2° cover less than 5 percent of the region. Overall, the topography of the Ganiki Planitia quadrangle can be characterized as flat, low lying, and nearly devoid of abrupt topographic variation. Complementing this gentle topography, the geoid anomaly has a generally linear gradient that decreases north-northwest from a high of ~20 m at the southern edge of the quadrangle (the northern border of the Atla Regio anomaly) to a low of -30 to -40 m along the northern edge (Konopliv and others, 1999). The vertical component of the gravity anomaly varies from ~50 mGal to -40 mGal, and integrated analysis of the gravity and topography data indicates that dynamically supported regions and areas of thickened crust are both present within the quadrangle. Because the Ganiki Planitia quadrangle is a plains-dominated lowland area that lies between several major physiographic provinces (namely, Atla Regio, Atalanta Planitia, and Vinmara Planitia), a geologic map of the region may yield insight into a wide array of important problems in Venusian geology. The current mapping effort and analysis complements previous efforts to characterize aspects of the region’s geology, for example stratigraphy near parabolic halo crater sites, volcanic plains emplacement, wrinkle ridges, volcanic feature distribution, volcano deformation, coronae characteristics, lithospheric flexure, and various features along a 30±7.58° N. geotraverse. Our current research focuses on addressing four specific questions. Has the dominant style of volcanic expression within the quadrangle varied in a systematic fashion over time? Does the tectonic deformation within the quadrangle record significant regional patterns that vary spatially or temporally, and if so what are the scales, orientations and sources of the stress fields driving this deformation? If mantle upwelling and downwelling have played a significant role in the formation of Atla Regio and Atalanta Planitia as has been proposed, does the geology of Ganiki Planitia record evidence of northwest-directed lateral mantle flow connecting the two sites? Finally, can integration of the tectonic and volcanic histories preserved within the quadrangle help constrain competing resurfacing models for Venus?

Investigating Mars: Kaiser Crater Dunes

NASA Image and Video Library

2018-01-31

This VIS image of the floor of Kaiser Crater contains a large variety of sand dune shapes and sizes. The "whiter" material is the hard crater floor surface. Kaiser Crater is located in the southern hemisphere in the Noachis region west of Hellas Planitia. Kaiser Crater is just one of several large craters with extensive dune fields on the crater floor. Other nearby dune filled craters are Proctor, Russell, and Rabe. Kaiser Crater is 207 km (129 miles) in diameter. The dunes are located in the southern part of the crater floor. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 35430 Latitude: -46.8699 Longitude: 19.4731 Instrument: VIS Captured: 2009-12-09 14:09 https://photojournal.jpl.nasa.gov/catalog/PIA22263

Pitted Landforms in Southern Hellas Planitia

NASA Image and Video Library

2015-03-25

This image is of a portion of the Southern plains region within Hellas, the largest impact basin on Mars, with a diameter of about 2300 kilometers 1400 miles, as observed by NASA Mars Reconnaissance Orbiter. There are three main phenomena apparent in this image. First, the faint dark streaks that criss-cross the terrain are dust devil tracks that clear the bright dust along their way. Second, the subtle overall bumpy "basketball" texture of the surface is formed by repeated seasonal freezing and thawing of the ice-rich regolith and is common at higher latitudes. Third, the large, elliptical, scalloped depressions are common in permafrost terrains in both hemispheres, where thick, latitude-dependent sedimentary mantles comprise the surface units. These mantles are composed of ice-rich sediments that degrade as the ice sublimates away and is heated either by the Sun or by locally higher geothermal gradients. Sublimation, or the direct change in phase from ice to gas, occurs on Mars because of its low density atmosphere. These depressions have steeper pole-facing slopes, whereas the equator-facing slopes gently fade into the surrounding terrain. At full resolution (see close up view), numerous sublimation pits and networks of polygonal cracks are visible on the steeper, unstable pole-ward facing slopes. The overall morphology of this terrain is characteristic of what is called "thermokarstic degradation processes," which is a term used to describe the formation of pits in an ice-rich terrain due to loss of ice creating pits and collapse features. http://photojournal.jpl.nasa.gov/catalog/PIA19350

Investigating Mars: Kaiser Crater Dunes

NASA Image and Video Library

2018-01-30

At the top of this VIS image crescent shaped dunes are visible. As the dunes approach a break in elevation the forms change to connect the crescents together forming long aligned dune forms. Kaiser Crater is located in the southern hemisphere in the Noachis region west of Hellas Planitia. Kaiser Crater is just one of several large craters with extensive dune fields on the crater floor. Other nearby dune filled craters are Proctor, Russell, and Rabe. Kaiser Crater is 207 km (129 miles) in diameter. The dunes are located in the southern part of the crater floor. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 34157 Latitude: -46.9336 Longitude: 18.9272 Instrument: VIS Captured: 2009-08-26 18:49 https://photojournal.jpl.nasa.gov/catalog/PIA22262

Lobo Vallis

NASA Image and Video Library

2018-04-20

Today's VIS image shows a small portion of Lobo Vallis near where it recombines with Kasei Valles and empties into Chryse Planitia. Kasei Valles is a huge channel system that drained the higher elevations of Tharsis into the low of Chryse Planitia. Orbit Number: 71206 Latitude: 28.9604 Longitude: 303.568 Instrument: VIS Captured: 2018-01-02 06:02 https://photojournal.jpl.nasa.gov/catalog/PIA22374

State of Utopia v. Jamie Davidson. 2002-2003 Oklahoma High School Mock Trial Program.

ERIC Educational Resources Information Center

Benischek, Sandra; Davis, Courtney; Horton, Johnathan; Longwell, Nicole; Williams, Keri

In the spring of 2001, illegal drug use had risen by 40% among teens in the town of Springdale, Utopia. School administrators and the Springdale Police Department decided to implement a crackdown on teen drug use in all high schools in Springdale. A high school principal received a tip on a hotline that Jamie Davidson, a senior, had been seen…

Geologic map of the Rusalka Planitia Quadrangle (V-25), Venus

USGS Publications Warehouse

Young, Duncan A.; Hansen, Vicki L.

2003-01-01

The Rusalka Planitia quadrangle (herein referred to as V-25) occupies an 8.1 million square kilometer swath of lowlands nestled within the eastern highlands of Aphrodite Terra on Venus. The region (25?-0? N., 150?-180? E.) is framed by the crustal plateau Thetis Regio to the southwest, the coronae of the Diana-Dali chasmata complex to the south, and volcanic rise Atla Regio to the west. Regions to the north, and the quadrangle itself, are part of the vast lowlands, which cover four-fifths of the surface of Venus. The often-unspectacular lowlands of Venus are typically lumped together as ridged or regional plains. However, detailed mapping reveals the mode of resurfacing in V-25's lowlands: a mix of corona-related flow fields and local edifice clusters within planitia superimposed on a background of less clearly interpretable extended flow fields, large volcanoes, probable corona fragments, and edifice-flow complexes. The history detailed within the Rusalka Planitia quadrangle is that of the extended evolution of long-wavelength topographic basins in the presence of episodes of extensive corona-related volcanism, pervasive low-intensity small-scale eruptions, and an early phase of regional circumferential shortening centered on central Aphrodite Terra. Structural reactivation both obscures and illuminates the tectonic development of the region. The data are consistent with progressive lithospheric thickening, although the critical lack of an independent temporal marker on Venus severely hampers our ability to test this claim and correlate between localities. Two broad circular basins dominate V-25 geology: northern Rusalka Planitia lies in the southern half of the quadrangle, whereas the smaller Llorona Planitia sits along the northwestern corner of V-25. Similar large topographic basins occur throughout the lowlands of Venus, and gravity data suggest that some basins may represent dynamic topography over mantle downwellings. Both planitiae include coronae and associated lava flows, as well as fields of volcanic shields. Within each basin, the local geologic histories are relatively well constrained; correlations between the planitiae are difficult without making assumptions. The region between the two basins contains large volcanoes, corona fragments, deformation belts, and shield fields embedded within a topographically higher heterogeneous expanse of rolling plains. V-25's most prominent structural grain is a suite of wrinkle ridges that arc around the southwest corner of the quadrangle. A patchy suite of northeast-trending assorted lineaments underlies much of the map area. Although these lineaments originally were narrow fractures, this structural suite appears to have subsequently opened up along extensional troughs near Corpman crater in the southwest corner of the map area and been reactivated as wrinkle ridges at Ran Colles in the middle of the southern boundary of V-25. Nineteen impact craters dot the quadrangle. Craters Yazruk, du Chatelet, and Caccini contribute large geology- obscuring ejecta halos. Crater densities are too low for either relative or absolute age dating. Ten splotches, presumably associated with meteor airbursts, also occur across V-25.

Chronology of wrinkle ridge formation and rate of crustal shortening on Lunae Planum, Mars

NASA Astrophysics Data System (ADS)

Karagoz, Oguzcan; Aksoy, M. Ersen; Erkeling, Gino

2017-04-01

The Lunae Planum, a plain between the Tharsis Montes and the Acidalia Planitia on Mars, represents a transitional zone from a volcanic rise to a lowland plain, respectively. From West to East at N20°, topography changes from 600 m to -750 m. Here, several wrinkle ridges that are compressional tectonic features formed by folding and thrust faulting [1], mark the surficial deformation of the martian crust. From the analysis of >25 wrinkle ridges in earlier studies a total shortening of ˜1840 m and a compressive strain of 0.29% has been suggested for the Lunae Planum [2]. In this study, we investigate the chronological order of geomorphic structures and determine the timing and duration of the crustal shortening of Lunae Planum. We use remote sensing mapping techniques [3] and crater size-frequency distribution measurements (CSFD) [e.g.,4,5]. In our analyses, we use HRSC (12.5 m/pixel), CTX (6 m/pixel) and HiRISE (0.3 m/pixel) satellite images and digital terrain models to document geomorphic structures such as wrinkles ridges, impact craters, crater ejecta blankets and intermontane plains. Our CSFD measurements of wrinkle ridges reveal an age distribution from 3.9 Ga to 3.0 Ga, with surfaces getting younger towards the East. Our findings are in accordance with earlier observations of greater shortening amounts towards the West (in older ridges) [2]. The age distribution of wrinkle ridges suggests a 9 Ma time interval for the proposed 1840 m horizontal shortening at a deformation rate of 2.04 x 10-3 mm/yr for compressional deformation on the Lunae Planum. [1] Watters, T.R., 2004, Elastic dislocation modeling of wrinkle ridges on Mars, Icarus, 171, 284-294. [2] Plescia, J.B., 1991.Wrinkle ridges in Lunae Planum, Mars: implications for shortening and strain. Geophys. Res. Lett. 18, 913-916. [3] Greeley, R. and Guest, J.E., 1987. Geologic map of the eastern equatorial region of Mars. USGS Miscellaneous Investigations Series Map. [4] Hartmann, W. K., and Neukum, G., 2001, Cratering chronology and the evolution of Mars. Space Sci. Rev. 96, 165-194. [5] Ivanov, B., 2001, Mars / Moon cratering ration estimates. Space Sci. Rev. 96, 87-104.

Stratigraphical evidence of late Amazonian periglaciation and glaciation in the Astapus Colles region of Mars

NASA Astrophysics Data System (ADS)

Soare, Richard J.; Osinski, Gordon R.

2009-07-01

Recent modeling of the meteorological conditions during and following times of high obliquity suggests that an icy mantle could have been emplaced in western Utopia Planitia by atmospheric deposition during the late Amazonian period [Costard, F.M., Forget, F., Madeleine, J.B., Soare, R.J., Kargel, J.S., 2008. Lunar Planet. Sci. 39. Abstract 1274; Madeleine, B., Forget, F., Head, J.W., Levrard, B., Montmessin, F., 2007. Lunar Planet. Sci. 38. Abstract 1778]. Astapus Colles (ABa) is a late Amazonian geological unit - located in this hypothesized area of accumulation - that comprises an icy mantle tens of meters thick [Tanaka, K.L., Skinner, J.A., Hare, T.M., 2005. US Geol. Surv. Sci. Invest., Map 2888]. For the most part, this unit drapes the early Amazonian Vastitas Borealis interior unit (ABvi); to a lesser degree it overlies the early Amazonian Vastitas Borealis marginal unit (ABvm) and the early to late Hesperian UP plains unit HBu2 [Tanaka, K.L., Skinner, J.A., Hare, T.M., 2005. US Geol. Surv. Sci. Invest., Map 2888]. Landscapes possibly modified by late-Amazonian periglacial processes [Costard, F.M., Kargel, J.S., 1995. Icarus 114, 93-112; McBride, S.A., Allen, C.C., Bell, M.S., 2005. Lunar Planet. Sci. 36. Abstract 1090; Morgenstern, A., Hauber, E., Reiss, D., van Gasselt, S., Grosse, G., Schirrmeister, L., 2007. J. Geophys. Res. 112, doi:10.1029/2006JE002869. E06010; Seibert, N.M., Kargel, J.S., 2001. Geophys. Res. Lett. 28, 899-902; Soare, R.J., Kargel, J.S., Osinski, G.R., Costard, F., 2007. Icarus 191, 95-112; Soare, R.J., Osinski, G.R., Roehm, C.L., 2008. Earth Planet. Sci. Lett. 272, 382-393] and glacial processes [Milliken, R.E., Mustard, J.F., Goldsby, D.L., 2003. J. Geophys. Res. 108 (E6), doi:10.1029/2002JE002005. 5057; Mustard, J.F., Cooper, C.D., Rifkin, M.K., 2001. Nature 412, 411-414; Tanaka, K.L., Skinner, J.A., Hare, T.M., 2005. US Geol. Surv. Sci. Invest., Map 2888] have been reported within the region. Researchers have assumed that the periglacial and glacial landscapes occur within the same geological unit, the ABa [i.e., Morgenstern, A., Hauber, E., Reiss, D., van Gasselt, S., Grosse, G., Schirrmeister, L., 2007. J. Geophys. Res. 112; doi:10.1029/2006JE002869. E06010; Tanaka, K.L., Skinner, J.A., Hare, T.M., 2005. US Geol. Surv. Sci. Invest., Map 2888]. In this study we use HiRISE (High Resolution Image Science Experiment, Mars Reconnaissance Orbiter) imagery to identify the stratigraphical separation of the two landscapes and show that periglacial landscape modification has occurred in the geological units that underlie the ABa, not in the ABa itself. Moreover, we suggest that the periglacial landscape extends well beyond the perimeter of the ABa and could be the product of "wet" cold-climate processes. These processes involve freeze-thaw cycles and intermittently stable liquid-water at or near the surface. By contrast, we propose that the ABa is a very recent late-Amazonian geological unit formed principally by "dry" cold-climate processes. These processes comprise accumulation (by atmospheric deposition) and ablation (by sublimation).

Proposed Mars Surveyor Landing Sites in Northern Meridiani Sinus, Southern Elysium Planitia, and Argyre Planitia

NASA Technical Reports Server (NTRS)

Parker, T. J.; Edgett, K. S.

1998-01-01

Our objective is to propose two landing sites that the Mars Surveyor 2001 Lander and Athena Rover could go to on Mars that should meet the safety requirements of the spacecraft landing system and optimize surface operations (chiefly driven by power and communications requirements). An additional site within Argyre Planitia, initially proposed by Parker to the Mars Surveyor Landing Site program, is also proposed for potential consideration for post-2001 missions to Mars, as it is well outside the current latitude limits for the Athena Rover. All three sites are designed to be situated as close to a diversity of geologic units within a few kilometers of the landing site so that diversity can be placed in a geologic context. This objective is very different from the Mars Pathfinder requirement to land at a site with a maximum chance for containing a diversity of rocks within a few tens of meters of the lander. That requirement was driven by the Sojourner mobility limit of a few tens of meters. It can be argued that the Athena project, with its much larger mobility capability, might actually want to avoid such a site, because placing collected samples in geologic context would be difficult. While it has been argued, both before and after the Mars Pathfinder landing, that the provenance for local blocks may be determined by orbiter spectra, primarily from the MGS TES instrument, our ability to do so has yet to be demonstrated. Indeed, several months after conclusion of the Pathfinder mission, we have yet to reach a consensus on the composition of local materials. Our primary data set for selecting a landing site within the latitude and elevation constraints of the 2001 mission is the Viking Orbiter image archive. The site must be selected to place the landing ellipse so as to avoid obvious hazards, such as steep slopes, large or numerous craters, or abundant large knobs. For this purpose, we chose a resolution limit of better than 50 m/pixel. This necessarily excludes from the present study images from current and future orbiter spacecraft, until such data does become readily available. Within each proposed region, it may be possible to identify additional sites once these data become available. Second, the fine-component thermal inertia data, should be greater than about 5 or 6 cgs Units (10(exp -3) cal/sq cm s(exp -0.5)/K). Low thermal inertias imply dusty environments, which could pose a mobility hazard. Similarly, the albedo of the site should not be particularly high, which would also suggest dusty surfaces. Low albedos are preferred, as they often coincide with low Viking red:violet ratios and indicate less dusty surfaces. Next, the Modeled Block Abundance should also not be too high or too low. Based on the Viking Lander and Mars Pathfinder experiences, percentages of blocks should be on the order of 5-25%. Too many blocks could pose a hazard to the landing and mobility. Too few blocks could also indicate a dusty surface. Primary Landing Site: Northern Meridiani Sinus (Proposed by T. J. Parker and K., S. Edgett) Vital Statistics: (1) Latitude, Longitude: 0-3 N, 350-2 W. *Elevation (Viking): about0.5-1.5 Ian. (2) Viking Orbiter Image coverage: Excellent coverage by 15 - 25 m/pixel images (orbits 709A and 410B). Possible stereo coverage in region where two orbits overlap (probably small parallax angle, as these orbits are not listed in NASA Contractor Report 3501) (3) Albedo: about .18 -.26 (4) Block Abundance: 5-26% (5)Fine-Component Thermal Inertia: 5-9 cgs units This region consists of bright deposits similar to those described by Edgett et al, that also lie within a prominent dark albedo region. These deposits are flat-lying, to such a degree that they ramp against topography rather than draping over it. This led Edgett and Parker to suggest that they may be subaqueous sediments, possibly lacustrine or marine evaporites, laid down sometime from the late Noachian to middle Hesperian (age determination pending crater counts). A contact between this material and elevated, dissected highlands to the south was identified , and is described by Edgett et al. Our desire in proposing this landing site is to sample the edge of this deposit where it has been exposed through etching, presumably eolian deflation (the deposit, though in the highlands, is itself only lightly to moderately cratered). This should enable access to in situ stratigraphy. The actual landing site will be selected where slopes are not expected to be steep, such that the rover itself should be able to traverse them and sample layered materials on the way, either up or down the slope. Perhaps due to uncertainties at this time as to the friability or meter-scale roughness of the deposit, it might make sense to place the landing ellipse on the exhumed highland surface adjacent to the deflated margin of the deposit and plan on driving to the deposit rather than landing on it and driving downslope. This should also enable imaging the margin for evidence of layering should it prove too difficult to climb. A target ellipse on the highland surface should also allow Athena access to ancient Noachian highland materials, particularly if placed near crater ejecta or an inlier of knobby material. Secondary Landing Site: Southern Elysium Planitia (Proposed by T. J. Parker) Vital Statistics: (1) Latitude, Longitude: 1.5-3.5 S, 195-198 W. (2) Elevation (Viking): -1.0 km. (3) Viking Orbiter Image coverage: Excellent coverage by 15 - 25 m/pixel images (orbit 725). Possible stereo coverage between images from beginning and end of orbit that overlap (probably small parallax angle) (4) Albedo: about .27-.28 (5) Block Abundance: 4-7% (6) Fine-Component Thermal Inertia: about 3 cgs units This region consists of eroded knobby material, probably of Noachian age, though much of the crater population has been destroyed, that is onlapped at a sharp contact by an extensive plains unit in southern Elysium Planitia that is Amazonian in age. The plains materials have been attributed to unusually low-viscosity flood lavas from fissures south of the Elysium volcanic rise, or to lacustrine materials associated with a large, Amazonian lake at the source of Marte Vallis. Parker and Schenk presented evidence in support of the latter interpretation, though they attributed the putative shore morphology to an embayment of a northern plains ocean into the southern Elysium region. Detailed examination of the margin of the deposit, showing erosion, not simply burial, of small crater rims and fluidized ejecta blankets, also points to lacustrine or marine sedimentation rather than volcanic plains burial. The plains surface exhibits a "crusty" appearance that many researchers have attributed to pressure ridges in lava flows. In a lacustrine context, they also resemble pressure ridges in desiccated evaporite deposits and salt-rimmed pools (now dry) similar in scale and morphology to spectacular, hundred meter-scale pool rims in alkaline Lake Natron, East African Rift. The eroded highland margin surface adjacent to these plains appears to be fairly smooth, even at 15 m/pixel. Isolated knob inliers are scattered from a few kilometers to several tens of "kilometers apart. Heights of the knobs have not been measured yet but, based on experience with similar features in the Pathfinder landing ellipse, are probably typically on the order of several tens of meters high and smaller, though some of the largest knobs in the region are probably up to a few hundred meters high. Two craters larger than a kilometer in diameter, with fluidized deposits, lie nearby the proposed landing site. Very high-resolution images from MOC should help to determine whether a landing site navigable by the Athena rover could be placed in this region. The space between knobs and craters is large enough to enable placement of a target landing ellipse between them but still provide access to one or more of them and to the margin of the Elysium plains material. Post -2001 Mars Surveyor Landing Site: Argyre Planitia (Proposed by T. J. Parker) Vital Statistics: (1) Latitude, Longitude: 55-56 S, 41-43 W. (2) Elevation (Viking): 1.0 km. (3) Viking Orbiter Image coverage: Excellent coverage by 40 m/pixel images (orbits 567B, 568B, and 569B). Excellent stereo coverage with large parallax angles over the entire landing site region, and much of central and southern Argyre. (4) Albedo: about .23-.24 (5) Block Abundance: No data (6) Fine-Component Thermal Inertia: No data The floors of both the Argyre and Hellas basins contain etched layered materials that are probably thick accumulations of channel or lacustrine sediments. The deposits in Hellas are much more eroded than those in Argyre, and Hellas lacks a channel outlet. Argyre is unique in that Uzboi Vallis flowed out of the basin, requiring overflow of a standing body of water within Argyre. This makes it the largest impact basin on Mars with channels both draining into it and flowing out from it. Hellas' channels may be catastrophic flood channels, whereas Argyre was fed by modest-scale valley networks, though the outlet at Uzboi Vallis was a catastrophic flood Highland craters and basins of this kind should be high-priority landing targets for missions intended to focus on the search for either prebiotic organic materials or even simple fossil microorganisms. Basins with internally-draining valley networks should be preferred over flood channels, as they could have provided the long-term influx of water favorable to the origin of life. (Catastrophic floods are not conducive to fossil preservation, due to their very short durations and high transportation energies). They also afford an opportunity to study the evolution of the planet's climate and volatiles during the period of time between the late Noachian and early Hesperian, when a drastic change from a proposed early warm, wet climate to one more closely resembling the modern environment is thought to have occurred. Large basin

Modeling glacial flow on and onto Pluto's Sputnik Planitia

NASA Astrophysics Data System (ADS)

Umurhan, O. M.; Howard, A. D.; Moore, J. M.; Earle, A. M.; White, O. L.; Schenk, P. M.; Binzel, R. P.; Stern, S. A.; Beyer, R. A.; Nimmo, F.; McKinnon, W. B.; Ennico, K.; Olkin, C. B.; Weaver, H. A.; Young, L. A.

2017-05-01

Observations of Pluto's surface made by the New Horizons spacecraft indicate present-day N2 ice glaciation in and around the basin informally known as Sputnik Planitia. Motivated by these observations, we have developed an evolutionary glacial flow model of solid N2 ice that takes into account its published thermophysical and rheological properties. This model assumes that glacial ice flows laminarly and has a low aspect ratio which permits a vertically integrated mathematical formulation. We assess the conditions for the validity of laminar N2 ice motion by revisiting the problem of the onset of solid-state buoyant convection of N2 ice for a variety of bottom thermal boundary conditions. Subject to uncertainties in N2 ice rheology, N2 ice layers are estimated to flow laminarly for thicknesses less than 400-1000 m. The resulting mass-flux formulation for when the N2 ice flows as a laminar dry glacier is characterized by an Arrhenius-Glen functional form. The flow model developed is used here to qualitatively answer some questions motivated by features we interpret to be a result of glacial flow found on Sputnik Planitia. We find that the wavy transverse dark features found along the northern shoreline of Sputnik Planitia may be a transitory imprint of shallow topography just beneath the ice surface suggesting the possibility that a major shoreward flow event happened relatively recently, within the last few hundred years. Model results also support the interpretation that the prominent darkened features resembling flow lobes observed along the eastern shoreline of the Sputnik Planitia basin may be the result of a basally wet N2 glacier flowing into the basin from the pitted highlands of eastern Tombaugh Regio.

General geology and geomorphology of the Mars Pathfinder landing site

USGS Publications Warehouse

Ward, A.W.; Gaddis, L.R.; Kirk, R.L.; Soderblom, L.A.; Tanaka, K.L.; Golombek, M.P.; Parker, T.J.; Greeley, Ronald; Kuzmin, R.O.

1999-01-01

The Mars Pathfinder (MPF) spacecraft landed on relatively young (late Hesperian-early Amazonian; 3.1-0.7 Ga) plains in Chryse Planitia near the mouth of Ares Vallis. Images returned from the spacecraft reveal a complex landscape of ridges and troughs, large hills and crater rims, rocks and boulders of various sizes and shapes, and surficial deposits, indicating a complex, multistage geologic history of the landing site. After the deposition of one or more bedrock units, depositional and erosional fluvial processes shaped much of the present landscape. Multiple erosional events are inferred on the basis of observations of numerous channels, different orientations of many streamlined tails from their associated knobs and hills, and superposition of lineations and streamlines. Medium- and small-scale features, interpreted to be related to late-stage drainage of floodwaters, are recognized in several areas at the landing site. Streamlined knobs and hills seen in Viking orbiter images support this inference, as they seem to be complex forms, partly erosional and partly depositional, and may also indicate a series of scouring and depositional events that, in some cases, further eroded or partially buried these landforms. Although features such as these are cited as evidence for catastrophic flooding at Ares Vallis, some of these features may also be ascribed to alternative primary or secondary depositional processes, such as glacial or mass-wasting processes. Close inspection of the landing site reveals rocks that are interpreted to be volcanic in origin and others that may be conglomeratic. If such sedimentary rocks are confirmed, fluvial processes have had a greater significance on Mars than previously thought. For the last several hundred million to few billion years, eolian processes have been dominant. Dunes and dune-like features, ventifacts, and deflation and exhumation features around several rocks probably are the most recent landforms. The relatively pristine nature of the overall landscape at the MPF site suggests weathering and erosion processes on Mars are exceptionally slow.

Isidis Crater Landslide

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

The landslide in this VIS image is located inside an impact crater located south of the Isidis Planitia region of Mars. As with the previous unnamed crater landslide, this one formed due to slope failure of the inner crater rim.

Image information: VIS instrument. Latitude -2.9, Longitude 90.8 East (269.2 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Yardangs: Nature's Weathervanes

NASA Image and Video Library

2017-11-28

The prominent tear-shaped features in this image from NASA's Mars Reconnaissance Orbiter (MRO) are erosional features called yardangs. Yardangs are composed of sand grains that have clumped together and have become more resistant to erosion than their surrounding materials. As the winds of Mars blow and erode away at the landscape, the more cohesive rock is left behind as a standing feature. (This Context Camera image shows several examples of yardangs that overlie the darker iron-rich material that makes up the lava plains in the southern portion of Elysium Planitia.) Resistant as they may be, the yardangs are not permanent, and will eventually be eroded away by the persistence of the Martian winds. For scientists observing the Red Planet, yardangs serve as a useful indicator of regional prevailing wind direction. The sandy structures are slowly eroded down and carved into elongated shapes that point in the downwind direction, like giant weathervanes. In this instance, the yardangs are all aligned, pointing towards north-northwest. This shows that the winds in this area generally gust in that direction. The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. [The original image scale is 55.8 centimeters (21 inches) per pixel (with 2 x 2 binning); objects on the order of 167 centimeters (65.7 inches) across are resolved.] North is up. https://photojournal.jpl.nasa.gov/catalog/PIA22119

Map of Martian Thorium at Mid-Latitudes

NASA Technical Reports Server (NTRS)

2003-01-01

This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element thorium. Thorium is a naturally radioactive element that exists in rocks and soils in extremely small amounts. The region of highest thorium content, shown in red, is found in the northern part of Acidalia Planitia (50 degrees latitude, -30 degrees longitude). Areas of low thorium content, shown in blue, are spread widely across the planet with significant low abundances located to the north of Olympus Mons (near 55 degrees latitude, -155 degrees longitude), to the east of the Tharsis volcanoes (-10 degrees latitude, -80 degrees longitude) and to the south and east of Elysium Mons (20 degrees latitude, 160 degrees longitude). Contours of constant surface elevation are also shown. The long continuous contour line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Analysis of terrestrial and Martian volcanic compositions using thermal emission spectroscopy

NASA Astrophysics Data System (ADS)

Wyatt, Michael Bruce

2002-11-01

This dissertation comprises four separate parts that address the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) investigation objective of determining and mapping the composition and distribution of surface minerals and rocks on Mars from orbit. In Part 1, laboratory thermal infrared spectra (5 25 μm, at 2 cm-1 spectral sampling), deconvolved modal mineralogies, and derived mineral and bulk rock chemistries of basalt, basaltic andesite, andesite, and dacite were used to evaluate and revise volcanic rock classification schemes. Multiple steps of classification were required to distinguish volcanic rocks, reflecting the mineralogic diversity and continuum of compositions that exists in volcanic rock types. In Part 2, laboratory spectral data were convolved to TES 10 cm-1 sampling to ascertain whether adequate results for volcanic rock classification can be obtained with lower spectral resolution, comparable to that obtained from Mars orbit. Modeled spectra, modeled modal mineralogies, and derived bulk rock chemistries at low (10 cm-1) spectral sampling provide good matches to measured and high (2 cm-1) spectral sampling modeled values. These results demonstrate the feasibility of using similar techniques and classification schemes for the interpretation of terrestrial laboratory samples and TES-resolution data. In Part 3, new deconvolved mineral abundances from TES data and terrestrial basalts using a spectral end-member set representing minerals common in unaltered and low-temperature aqueously altered basalts were used to reclassify martian surface lithologies. The new formulations maintain the dominance of unaltered basalt in the southern highlands, but indicate the northern lowlands can be interpreted as weathered basalt. The coincidence between locations of altered basalt and a previously suggested northern ocean basin implies that lowland plains materials may be basalts altered under submarine conditions and/or weathered basaltic sediment transported into this depocenter. In Part 4, results from the previous parts are applied to examine the distribution of TES-derived surface compositions in the Oxia Palus region on Mars through high-spatial resolution mapping. Features of interest within Oxia Palus include volcanic/sedimentary materials in southern Acidalia Planitia, low-albedo crater floors and wind streaks in western Arabia Terra, and channel outflow deposits of the Mars Pathfinder (MP) landing site.

A highland sample strategy for Pathfinder

NASA Technical Reports Server (NTRS)

Dehon, Rene A.

1994-01-01

Potential landing sites are confined to latitudes between 0 deg and 30 deg N and surfaces below 0 km elevation. The landing ellipse is 100 x 200 km oriented N 74 deg E. The constraints essentially eliminate the slopes of Elysium Mons, Olympus Mons, Tharsis Ridge, Lunae Plaunum, all the southern highlands, and almost all the Noachian material of Arabia Terra. Those areas that remain as potential landing sites are chiefly lowland plains of Amazonis Chryse, Isidis, and Elysium Planitia. Any attempt to sample highland material further constrains the possible landing sites by eliminating areas of Hesperian or Amazonian lavas and sediments. One possible sampling strategy is to sample materials within those few 'highland' terrains that extend to low elevations. A second strategy is to sample materials at the mouth of an outflow channel that drains from the highlands. Potential landing sites include outflow channel material at the edge of Chryse Planitia and highland materials bordering southern Amazonis Planitia.

An Analysis and Comparison of Two Short Writings: "Inaugural Address at the University of St. Andrew's" by J.S. Mill and "The University of Utopia" by R.M. Hutchins, Based on Five Criteria.

ERIC Educational Resources Information Center

Poirier, Jeannine M.

Focusing on the concept of education for work vs. education for living, the author presents a comparative analysis of two works on liberal education, each of which was originally delivered orally to university students: "The Inaugural Address at the University of St. Andrew" by John Stuart Mill and "The University of Utopia" by…

Scientific rationale for selecting northwest Isidis Planitia (14 deg - 17 deg N latitude, 278 deg - 281 deg longitude) as a potential Mars Pathfinder landing site

NASA Technical Reports Server (NTRS)

Parker, Tim J.; Rice, Jim W.

1994-01-01

The northwest Isidis Basin offers a unique opportunity to land near a fretted terrain lowland/upland boundary that meets both the latitudinal and elevation requirements imposed on the spacecraft. The landing site lies east of erosional scarps and among remnant massif inselbergs of the Syrtis Major volcanic plains. The plains surface throughout Isidis exhibits abundant, low-relief mounds that are the local expression of the 'thumbprint terrain' that is common within a few hundred kilometers of the lowland/upland boundary. The massif inselbergs are not as numerous nor as massive as those fretted terrains to the northwest, so local slopes are not expected to be steep. Neither feature should pose a serious threat to the lander. Landing on or adjacent to one of these features would enhance the science return and would help to pinpoint the landing site in Viking and subsequent orbiter images by offering views of landmarks beyond the local horizon.

Beagle-2 landing site atlas

NASA Astrophysics Data System (ADS)

Michael, G.; Chicarro, A.; Rodionova, J.; Shevchenko, V.; Ilukhina, J.; Kozlova, K.

2003-04-01

The Beagle-2 lander of the Mars Express mission will come to rest on the surface of Isidis Planitia in late December 2003 to carry out a range of geochemistry and exobiology experi-ments. We are compiling an atlas of the presently available data products pertinent to the landing site at 11.6N 90.75E, which is intended for distribution both as a printed and an electronic resource. The atlas will include Viking and MOC-WA image mosaics, and a catalogue of high-resolution im-ages from MOC and THEMIS with location maps. There will be various MOLA topography-based products: colour-scaled, contoured, and shaded maps, slope, and detrended relief. Simulated camera panoramas from various potential landing locations may assist in determining the spacecraft’s position. Other maps, both raw, and in composites with image mosa-ics, will cover TES thermal inertia and spectroscopy, and Odyssey gamma and neutron spectroscopy. Maps at the scale of the Isidis context will additionally cover geology, tem-perature cycles, and atmospheric circulation. Sample are shown below.

Map of Martian Thorium at Mid-Latitudes

NASA Image and Video Library

2003-03-13

This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element thorium. Thorium is a naturally radioactive element that exists in rocks and soils in extremely small amounts. The region of highest thorium content, shown in red, is found in the northern part of Acidalia Planitia (50 degrees latitude, -30 degrees longitude). Areas of low thorium content, shown in blue, are spread widely across the planet with significant low abundances located to the north of Olympus Mons (near 55 degrees latitude, -155 degrees longitude), to the east of the Tharsis volcanoes (-10 degrees latitude, -80 degrees longitude) and to the south and east of Elysium Mons (20 degrees latitude, 160 degrees longitude). Contours of constant surface elevation are also shown. The long continuous contour line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south. http://photojournal.jpl.nasa.gov/catalog/PIA04257

Generation of Martian chaos and channels by debris flows

NASA Technical Reports Server (NTRS)

Nummedal, D.; Prior, D. B.

1981-01-01

A debris flow mechanism is proposed to account for the formation of chaos and the large channels debouching into Crysae Planitia from the adjacent southern uplands of Mars. Based on considerations of the juxtaposition of individual channel environments, the morphological assemblages within each environment and flow dynamics, it is suggested that the debris flows were triggered by the large-scale failure of subsurface sediments, possibly initiated by a seismic event. During the initial, slow-moving phase of the flow, the debris would have formed gently sinuous channels with multiple side-wall slumps, grooves and ridges, and elongate erosional remnants. The flow would have gained mobility as the debris moved downslope, producing travel distances greatly in excess of those characteristic of terrestrial examples, and eroded, streamlined remnants at the distal reaches of the channel. Finally, due to internal and boundary friction, the flow would have been slowed down once it entered the Chryse plains, resulting in a thin debris blanket with no depositional relief.

Selection of the InSight landing site

USGS Publications Warehouse

Golombek, M.; Kipp, D.; Warner, N.; Daubar, Ingrid J.; Fergason, Robin L.; Kirk, Randolph L.; Beyer, R.; Huertas, A.; Piqueux, Sylvain; Putzig, N.E.; Campbell, B.A.; Morgan, G. A.; Charalambous, C.; Pike, W. T.; Gwinner, K.; Calef, F.; Kass, D.; Mischna, M A; Ashley, J.; Bloom, C.; Wigton, N.; Hare, T.; Schwartz, C.; Gengl, H.; Redmond, L.; Trautman, M.; Sweeney, J.; Grima, C.; Smith, I. B.; Sklyanskiy, E.; Lisano, M.; Benardini, J.; Smrekar, S.E.; Lognonne, P.; Banerdt, W. B.

2017-01-01

The selection of the Discovery Program InSight landing site took over four years from initial identification of possible areas that met engineering constraints, to downselection via targeted data from orbiters (especially Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) and High-Resolution Imaging Science Experiment (HiRISE) images), to selection and certification via sophisticated entry, descent and landing (EDL) simulations. Constraints on elevation (≤−2.5 km">≤−2.5 km≤−2.5 km for sufficient atmosphere to slow the lander), latitude (initially 15°S–5°N and later 3°N–5°N for solar power and thermal management of the spacecraft), ellipse size (130 km by 27 km from ballistic entry and descent), and a load bearing surface without thick deposits of dust, severely limited acceptable areas to western Elysium Planitia. Within this area, 16 prospective ellipses were identified, which lie ∼600 km north of the Mars Science Laboratory (MSL) rover. Mapping of terrains in rapidly acquired CTX images identified especially benign smooth terrain and led to the downselection to four northern ellipses. Acquisition of nearly continuous HiRISE, additional Thermal Emission Imaging System (THEMIS), and High Resolution Stereo Camera (HRSC) images, along with radar data confirmed that ellipse E9 met all landing site constraints: with slopes <15° at 84 m and 2 m length scales for radar tracking and touchdown stability, low rock abundance (<10 %) to avoid impact and spacecraft tip over, instrument deployment constraints, which included identical slope and rock abundance constraints, a radar reflective and load bearing surface, and a fragmented regolith ∼5 m thick for full penetration of the heat flow probe. Unlike other Mars landers, science objectives did not directly influence landing site selection.

Near-Surface Geologic Units Exposed Along Ares Vallis and in Adjacent Areas: A Potential Source of Sediment at the Mars Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

Treiman, Allan H.

1997-01-01

A sequence of layers, bright and dark, is exposed on the walls of canyons, impact craters and mesas throughout the Ares Vallis region, Chryse Planitia, and Xanthe Terra, Mars. Four layers can be seen: two pairs of alternating dark and bright albedo. The upper dark layer forms the top surface of many walls and mesas. The upper dark-bright pair was stripped as a unit from many streamlined mesas and from the walls of Ares Valles, leaving a bench at the top of the lower dark layer, approximately 250 m below the highland surface on streamlined islands and on the walls of Ares Vallis itself. Along Ares Vallis, the scarp between the highlands surface and this bench is commonly angular in plan view (not smoothly curving), suggesting that erosion of the upper dark-bright pair of layers controlled by planes of weakness, like fractures or joints. These near-surface layers in the Ares Vallis area have similar thicknesses, colors, and resistances to erosion to layers exposed near the tops of walls in Valles Marineris (Treiman et al.) and may represent the same pedogenic hardpan units. From this correlation, and from analogies with hardpans on Earth, the light-color layers may be cemented by calcite or gypsum. The dark layers are likely cemented by an iron-bearing mineral. Mars Pathfinder instruments should permit recognition and useful analyses of hardpan fragments, provided that clean uncoated surfaces are accessible. Even in hardpan-cemented materials, it should be possible to determine the broad types of lithologies in the Martian highlands. However, detailed geochemical modeling of highland rocks and soils may be compromised by the presence of hardpan cement minerals.

Investigating Mars: Kaiser Crater Dunes

NASA Image and Video Library

2018-01-23

Kaiser Crater is located in the southern hemisphere in the Noachis region west of Hellas Planitia. Kaiser Crater is just one of several large craters with extensive dune fields on the crater floor. Other nearby dune filled craters are Proctor, Russell, and Rabe. Kaiser Crater is 207 km (129 miles) in diameter. The dunes are located in the southeastern part of the crater floor. Most of the individual dunes in Kaiser Crater are barchan dunes. Barchan dunes are crescent shaped with the points of the crescent pointing downwind. The sand is blown up the low angle side of the dune and then tumbles down the steep slip face. This dune type forms on hard surfaces where there is limited amounts of sand. Barchan dunes can merge together over time with increased sand in the local area. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 1036 Latitude: -46.7795 Longitude: 20.2075 Instrument: VIS Captured: 2002-03-09 20:07 https://photojournal.jpl.nasa.gov/catalog/PIA22172

Investigating Mars: Kaiser Crater Dunes

NASA Image and Video Library

2018-01-29

This VIS image of Kaiser Crater shows a region of the dunes with varied appearances. The different dune forms developed due to different amounts of available sand, different wind directions, and the texture of the crater floor. The dune forms change from the bottom to the top of the image - large long connected dunes, to large individual dunes, to the very small individual dunes at the top of the image. Kaiser Crater is located in the southern hemisphere in the Noachis region west of Hellas Planitia. Kaiser Crater is just one of several large craters with extensive dune fields on the crater floor. Other nearby dune filled craters are Proctor, Russell, and Rabe. Kaiser Crater is 207 km (129 miles) in diameter. The dunes are located in the southern part of the crater floor. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 17686 Latitude: -46.6956 Longitude: 19.8394 Instrument: VIS Captured: 2005-12-09 13:25 https://photojournal.jpl.nasa.gov/catalog/PIA22261

Investigating Mars: Kaiser Crater Dunes

NASA Image and Video Library

2018-01-24

This VIS image of Kaiser Crater shows individual dunes and where the dunes have coalesced into longer dune forms. The addition of sand makes the dunes larger and the intra-dune areas go from sand-free to complete coverage of the hard surface of the crater floor. With a continued influx of sand the region will transition from individual dunes to a sand sheet with surface dune forms. Kaiser Crater is located in the southern hemisphere in the Noachis region west of Hellas Planitia. Kaiser Crater is just one of several large craters with extensive dune fields on the crater floor. Other nearby dune filled craters are Proctor, Russell, and Rabe. Kaiser Crater is 207 km (129 miles) in diameter. The dunes are located in the southern part of the crater floor. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 1423 Latitude: -46.9573 Longitude: 18.6192 Instrument: VIS Captured: 2002-04-10 16:44 https://photojournal.jpl.nasa.gov/catalog/PIA22173

Chaotic Terrain

NASA Technical Reports Server (NTRS)

2003-01-01

[figure removed for brevity, see original site]

Released 4 June 2003

Chaotic terrain on Mars is thought to form when there is a sudden removal of subsurface water or ice, causing the surface material to slump and break into blocks. The chaotic terrain in this THEMIS visible image is confined to a crater just south of Elysium Planitia. It is common to see chaotic terrain in the vicinity of the catastrophic outflow channels on Mars, but the terrain in this image is on the opposite side of the planet from these channels, making it somewhat of an oddity.

Image information: VIS instrument. Latitude -5.9, Longitude 108.1 East (251.9 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Utopia documents: linking scholarly literature with research data

PubMed Central

Attwood, T. K.; Kell, D. B.; McDermott, P.; Marsh, J.; Pettifer, S. R.; Thorne, D.

2010-01-01

Motivation: In recent years, the gulf between the mass of accumulating-research data and the massive literature describing and analyzing those data has widened. The need for intelligent tools to bridge this gap, to rescue the knowledge being systematically isolated in literature and data silos, is now widely acknowledged. Results: To this end, we have developed Utopia Documents, a novel PDF reader that semantically integrates visualization and data-analysis tools with published research articles. In a successful pilot with editors of the Biochemical Journal (BJ), the system has been used to transform static document features into objects that can be linked, annotated, visualized and analyzed interactively (http://www.biochemj.org/bj/424/3/). Utopia Documents is now used routinely by BJ editors to mark up article content prior to publication. Recent additions include integration of various text-mining and biodatabase plugins, demonstrating the system's ability to seamlessly integrate on-line content with PDF articles. Availability: http://getutopia.com Contact: teresa.k.attwood@manchester.ac.uk PMID:20823323

Near Surface Stratigraphy and Regolith Production in Southwestern Elysium Planitia, Mars: Implications for Hesperian-Amazonian Terrains and the InSight Lander Mission

NASA Astrophysics Data System (ADS)

Warner, N. H.; Golombek, M. P.; Sweeney, J.; Fergason, R.; Kirk, R.; Schwartz, C.

2017-10-01

The presence of rocks in the ejecta of craters at the InSight landing site in southwestern Elysium Planitia indicates a strong, rock-producing unit at depth. A finer regolith above is inferred by the lack of rocks in the ejecta of 10-m-scale craters. This regolith should be penetrable by the mole of the Heat Flow and Physical Properties Package (HP3). An analysis of the size-frequency distribution (SFD) of 7988 rocky ejecta craters (RECs) across four candidate landing ellipses reveals that all craters >200 m in diameter and {<}750 ± 30 Ma in age have boulder-sized rocks in their ejecta. The frequency of RECs however decreases significantly below this diameter (D), represented by a roll-off in the SFD slope. At 30 m < D < 200 m, the slope of the cumulative SFD declines to near zero at D < 30 m. Surface modification, resolution limits, or human counting error cannot account for the magnitude of this roll-off. Rather, a significant population of <200 m diameter fresh non-rocky ejecta craters (NRECs) here indicates the presence of a relatively fine-grained regolith that prevents smaller craters from excavating the strong rock-producing unit. Depth to excavation relationships and the REC size thresholds indicate the region is capped by a regolith that is almost everywhere 3 m thick but may be as thick as 12 to 18 m. The lower bound of the thickness range is independently confirmed by the depth to the inner crater in concentric or nested craters. The data indicate that 85% of the InSight landing region is covered by a regolith that is at least 3 m thick. The probability of encountering rockier material at depths >3 m by the HP3 however increases significantly due to the increase in boulder-size rocks in the lower regolith column, near the interface of the bedrock.

Mars Shoreline Tests: Contact between Lycus Sulci and Amazonis Planitia

NASA Technical Reports Server (NTRS)

1999-01-01

This picture is the first MOC high resolution image that showed the contact between the Lycus Sulci uplands and Amazonis Planitia lowlands. In this subframe of MOC image SPO 1-225/03, Amazonis and Lycus Sulci are separated by a subtle rise that runs diagonally across the scene from near the lower left toward the upper right. The Amazonis plains are toward the top of the picture, the Lycus Sulci uplands are toward the bottom. Both surfaces have been cratered by small meteoroid impacts. The Amazonis plains surface has many small, nearly parallel ridges that may have formed by wind erosion. These ridges are not found on the Lycus Sulci surface. None of the features seen in this image look like typical seashore landforms found on Earth--i.e., there are no beaches, windblown coastal dunes, or even the wave-cut cliff that was thought to exist on the basis of previous Viking images. The picture is illuminated from the lower right and was acquired in April 1998. [figure removed for brevity, see original site]

Lycus Sulci is the name of a region of hills and ridges located north and northwest of the famous giant volcano, Olympus Mons (see inset, above). Viking images of the area where the western margin of the Lycus Sulci meets the smooth Amazonis plains (upper left in the figure above) led some researchers to conclude that the two surfaces were in contact along a cliff. The proposed cliff faces toward the smooth plains, and thus it was suggested that this might be the kind of cliff that forms from erosion by waves in a body of water as they break against a coastline. During the first year that Mars Global Surveyor (MGS) was orbiting the red planet (1997-1998), the Mars Orbiter Camera (MOC) acquired three high-resolution images along the contact between the Lycus Sulci hills and the Amazonis plains. The location of the portion of each image that is illustrated below is shown in this figure by a small, white box identified by the archival image number (e.g., 'SPO2-428/03' refers to the 3rd image taken on the 428th orbit during the Science Phasing Orbits 2 phase of the MGS mission). The regional context view shown here is a portion of Viking orbiter image 851A29; its center is near 32oN, 114oW and it is illuminated from the right. [figure removed for brevity, see original site] MRPS 95319

Lycus Sulci and Amazonis Planitia are shown here separated by a rise that runs diagonally across the scene from near the lower left toward the upper right. This picture is a subframe of MOC image SPO2-428/03, taken in July 1998. The Lycus Sulci uplands here are more roughly-textured than in the previous image, and the flat Amazonis plains appear to be more smooth and lack the small parallel ridges seen in the earlier view. The lack of the small ridges might be real, or they might be present but cannot be seen because this picture has a lower resolution than the previous one. This image, too, shows that the contact between Amazonis and Lycus Sulci is not a cliff, and once again there are no features that can be unambiguously identified as coastal landforms. [figure removed for brevity, see original site] MRPS 95320

This is the third MOC image obtained during the first year of MGS operations that shows the contact between Lycus Sulci and Amazonis Planitia. This picture, a subframe of SPO2-483/08, was taken in August 1998. The Lycus Sulciup lands at this location dominate the lower half of the picture, while the Amazonis plains cover the upper half. The uplands here exhibit many small buttes (bumps or knobs in lower right of the scene), and the contact zone between the upland and lowland includes a triangular-shaped ridge (center/right). As with the earlier views of the contact between Lycus Sulci and Amazonis, no features of obvious origin by coastal processes (e.g., erosion by waves crashing against ashore) are seen. The scene is illuminated from the right. [figure removed for brevity, see original site] [figure removed for brevity, see original site]

The first picture above shows the regional context of a Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) high-resolution image that was targeted in August 1998 with the intent to test the hypothesis that the northern plains of Mars were once the site of a vast ocean of liquid water. The second picture shows the resulting MOC image, numbered SPO2-515/05 and located at 40.0oN, 6.0oW in the transition zone between the Cydonia region and Acidalia Planitia, Mars.

The context image (first picture) includes several dark lines, some of which are labeled I and some are labeled G. These dark lines were proposed in previous, peer-reviewed scientific papers to be possible ocean shorelines located along the margins of the martian northern plains. Line I was called the Interior Plains Boundary, and line G was called the Gradational Boundary. The MGS MOC high resolution image was targeted such that it would examine the nature of line I, the Interior Plains Boundary.

The second figure shows the MOC high resolution view. The picture on the left side of the figure (second image) is the full MOC image and the white box indicates the location of the expanded view to the right. In the expanded view (the center of the figure), the location of line I--the proposed shoreline--is shown by a dashed curve. The dashed curve follows a subtle, shallow trough. None of the types of coastal landforms common on Earth--such as a beach, wave-cut cliff or terrace, or coastal dune fields, are seen at this location. If an ocean had once been present, then the water would have covered the top 2/3 of the expanded view--i.e., water would have lapped up against the rounded mounds in the lower 1/3 of this picture. Instead of coastal landforms, the MOC image exhibits a dark surface in its upper 1/3. The dark surface covers older, rounded hills and has a low, lobate escarpment along its southern margin. This escarpment faces south--that is, it faces toward the once-proposed coastline. In other words, the escarpment faces in a direction opposite of what would be expected for a coastal environment.

The context picture uses Viking orbiter image 561a24 as a base. [figure removed for brevity, see original site] [figure removed for brevity, see original site] MRPS 50586

Mars Global Surveyor's (MGS) Mars Orbiter Camera (MOC) took the above picture (second of the two) of some massifs and mesas in the Cydonia region of Mars in early September 1998. The purpose of this image--number SPO2-532/04--was to test the hypothesis that the martian northern plains were once the site of an ocean or large sea. According to this hypothesis, and according to peer-reviewed and published maps, each one of the mesas and massifs in the two pictures above should have shorelines around their margins. The hypothesis holds that these were once islands and that waves would lap--and sometimes crash--against these landforms, rip off huge chunks of rock, and create steep cliffs and stair-stepped terraces in the rock.

The first picture above shows the regional context of the MOC high resolution view in Cydonia. The context picture, from Viking orbiter image 227S11, is illuminated from the right. The second picture above is a figure that shows the full SPO2-532/04 MOC image and two expanded views of portions of this image. Mesas are flat-topped uplands, and massifs are the more triangular, massive peaks. If an ocean had been present in this region, terraces that indicate erosion or bathtub rings of salt or carbonate deposits left by the retreat of this ocean as it dried up might be found around each mesa and massif. No such features are found, nor is it at all obvious why these mesas and massifs were portrayed in previously published figures as having shorelines around them. The MOC image is illuminated from the left. [figure removed for brevity, see original site] [figure removed for brevity, see original site]

If the northern plains of Mars had ever been the site of a vast ocean, then any highlands that protrude above these plains might be expected to exhibit shorelines. The somewhat curved, flat-topped mesa seen in Viking image 026A72 (first image)is bounded by a dark band. Prior to the Mars Global Surveyor (MGS) mission, this mesa was interpreted by some researchers as having been a possible island in an ancient, northern plains ocean. The dark band was interpreted to be a shoreline resulting from the action of waves lapping against the island's coast.

A high resolution image of the banded mesa--located on the Acidalia plains around 45oN, 7oW--was acquired by the MGS Mars Orbiter Camera (MOC) in August 1998, over twenty years after the Viking image was taken. A subframe of this image--SPO2-515/06--is shown in the second image. In the MOC image, the dark band resolves into a series of narrower bright and dark bands. Each band has a slightly different texture and brightness. Furthermore, what appeared to be a sunlit escarpment bounding the north side of the mesa in the Viking image appears in the MOC image to be only a shallow slope rather than a scarp or cliff. The origin of the different bands is not known, but the most likely explanation that would be consistent with other MOC observations of Mars is that the mesa consists of layered rock, and that each band is an outcropping of a different layer of this rock. The different textures would result from the differing resistance to erosion of each layer. Both images shown here are illuminated from the left.

What Eating at Pluto?

NASA Image and Video Library

2016-03-10

Scientists on NASA's New Horizons mission have discovered what looks like a giant bite-mark on the planet's surface. In this image, north is up. The southern portion of the left inset above shows the cratered plateau uplands informally named Vega Terra (note that all feature names are informal). This terrain is separated from the young, nearly uncratered, mottled plains of Piri Planitia in the center of the image by a generally north-facing jagged scarp called Piri Rupes. The scarp breaks up into isolated mesas in several places. Cutting diagonally across Piri Planitia is the long extensional fault of Inanna Fossa, which stretches eastward 370 miles (600 kilometers) from here to the western edge of the great nitrogen ice plains of Sputnik Planum. Compositional data from the New Horizons spacecraft's Ralph/Linear Etalon Imaging Spectral Array (LEISA) instrument, shown in the right inset, indicate that the plateau uplands south of Piri Rupes are rich in methane ice (shown in false color as purple). Scientists speculate that sublimation of methane may be causing the plateau material to erode along the face of the scarp cliffs, causing them to retreat south and leave the plains of Piri Planitia in their wake. Compositional data also show that the surface of Piri Planitia is more enriched in water ice (shown in false color as blue) than the plateau uplands, which may indicate that Piri Planitia's surface is made of water ice bedrock, on top of which the layer of retreating methane ice had been sitting. Because the surface of Pluto is so cold, the water ice behaves like rock and is immobile. The light/dark mottled pattern of Piri Planitia in the left inset is reflected in the composition map, with the lighter areas corresponding to areas richer in methane – these may be remnants of methane that have not yet sublimated away entirely. The inset at left shows about 650 feet (200 meters) per pixel; the image measures approximately 280 miles (450 kilometers) long by 255 miles (410 kilometers) wide. It was obtained by New Horizons at a range of approximately 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before the spacecraft's closest approach to Pluto on July 14, 2015.The LEISA data at right was gathered when the spacecraft was about 29,000 miles (47,000 kilometers) from Pluto; best resolution is 1.7 miles (2.7 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20531

Thermal Springs and the Search for Past Life on Mars

NASA Technical Reports Server (NTRS)

DesMarais, D. J.; Farmer, J. D.; Walter, M. R.

1995-01-01

Ancient thermal spring sites have several features which make them significant targets in a search for past life. Chemical (including redox) reactions in hydrothermal systems possibly played a role in the origin of life on Earth and elsewhere. Spring waters frequently contain reduced species (sulfur compounds, Fe(sup +2), etc.) which can provide chemical energy for organic synthesis. Relatively cool hydrothermal systems can sustain abundant microbial life (on Earth, at temperatures greater than 110 C). A spring site on Mars perhaps might even have maintained liquid water for periods sufficiently long to sustain surface-dwelling biota had they existed. On Earth, a variety of microbial mat communities can be sampled along the wide range of temperatures surrounding the spring, thus offering an opportunity to sample a broad biological diversity. Thermal spring waters frequently deposit minerals (carbonates, silica, etc.) which can entomb and preserve both fluid inclusions and microbial communities. These deposits can be highly fossiliferous and preserve biological inclusions for geologically long periods of time. Such deposits can cover several square km on Earth, and their distinctive mineralogy (e.g., silica- and/or carbonate-rich) can contrast sharply with that of the surrounding region. As with Martian volcanoes, Martian thermal spring complexes and their deposits might typically be much larger than their counterparts on Earth. Thus Martian spring deposits are perhaps readily detectable and even accessible. Elysium Planitia is an example of a promising region where hydrothermal activity very likely remobilized ground ice and sustained springs.

Radar, visual and thermal characteristics of Mars: Rough planar surfaces

USGS Publications Warehouse

Schaber, G.G.

1980-01-01

High-resolution Viking Orbiter images (10 to 15 m/pixel) contain significant information on Martian surface roughness at 25- to 100-m lateral scales, whereas Earth-based radar observations of Mars are sensitive to roughness at lateral scales of 1 to 30 m, or more. High-rms slopes predicted for the Tharsis-Memnonia-Amazonis volcanic plains from extremely weak radar returns (low peak radar cross section) are qualitatively confirmed by the Viking image data. Large-scale, curvilinear (but parallel) ridges on lava flows in the Memnonia Fossae region are interpreted as innate flow morphology caused by compressional foldover of moving lava sheets of possible rhyolite-dacite composition. The presence or absence of a recent mantle of fine-grained eolian material on the volcanic surfaces studied was determined by the visibility of fresh impact craters with diameters less than 50 m. Lava flows south and west of Arsia Mons, and within the large region of low thermal inertia centered on Tharsis Montes (H. H. Kieffer et al., 1977, J. Geophys. Res.82, 4249-4291), were found to possess such a recent mantle. At predawn residual temperatures ??? -10K (south boundary of this low-temperature region), lava flows are shown to have relatively old eolian mantles. Lava flows with surfaces modified by eolian erosion and deposition occur west-northwest of Apollinaris Patera at the border of the cratered equatorial uplands and southern Elysium Planitia. Nearby yardangs, for which radar observations indicate very high-rms slopes, are similar to terrestrial features of similar origin. ?? 1980.

Proposed Mars Surveyor landing sites in northern Meridiani Sinus, southern Elysium Planitia, and Argyre Planitia

NASA Astrophysics Data System (ADS)

Parker, T. J.; Edgett, K. S.

1998-01-01

Introduction: Our objective is to propose two landing sites that the Mars Surveyor 2001 Lander and Athena rover could go to on Mars that would meet the safety requirements of the spacecraft landing system and optimize surface operations (chiefly driven by power and communications requirements). An additional site within Argyre Planitia, initially proposed by Parker to the Mars Surveyor Landing Site program, is also proposed for potential consideration for post-2001 missions to Mars, as it is well outside the current latitude limits for the Athena rover. All three sites are designed to be situated as close to a diversity of geologic units within a few kilometers of the landing site so that diversity can be placed in a geologic context. This objective is very different from the Mars Pathfinder requirement to land at a site with a maximum chance for containing a diversity of rocks within a few tens of meters of the lander. That requirements was driven by the Sojourner mobility limit of a few tens of meters. It can be argued that the Athena project, with its much larger mobility capability, might actually want to avoid such a site, because placing collected samples in geologic context would be difficult. While it has been argued, both before and after the Mars Pathfinder landing, that the provenance for local blocks may be determined by orbiter spectra, primarily from the MGS TES instrument, our ability to do so has yet to be demonstrated. Indeed, several months after conclusion of the Pathfinder mission, we have yet to reach a consensus on the composition of local materials. Our primary data set for selecting a landing site within the latitude and elevation constraints for the 2001 mission is the Viking Orbiter image archive. The site must be selected to place the landing ellipse so as to avoid obvious hazards, such as steep slopes, large or numerous craters, or abundant large knobs. For this purpose, we chose a resolution limit of better than 50 m/pixel. This necessarily excludes from the present study images from current and future orbiter spacecraft, until such data does become readily available. Within each proposed region, it may be possible to identify additional sites once these data become available. Second, the fine-component thermal inertia data [1], compiled by P. Christensen and made available to the Mars Pathfinder project, should be greater than about 5 or 6 cgs units (10^-3 cal cm^-2 s^-0.5 K^-1). Low thermal inertias imply dusty environments, which could pose a mobility hazard. Similarly, the albedo ([2] digital file made available to the Mars Pathfinder project by P. Christensen) of the site should not be particularly high, which would also suggest dusty surfaces. Low albedos are preferred, as they often coincide with low Viking red:violet ratios and indicate less dusty surfaces. Next, the Modeled Block Abundance [1] should also not bee too high or too low. Based on the Viking Lander and Mars Pathfinder experiences, percentages of blocks should be on the order of 5-22%. Too many blocks could pose a hazard to the landing and mobility. Too few blocks could also indicate a dusty surface. Primary Landing Site: Northern Meridiani Sinus (Proposed by T. J. Parker and K. S. Edgett) Vital Statistics: *Latitude, Longitude: 0-3°N, 350-2°W. *Elevation (Viking): ~0.5-1.5 km. *Viking Orbiter Image coverage: Excellent coverage by 15-25 m/pixel images (orbits 709A and 410B). Possible stereo coverage in region where two orbits overlap (probably small parallax angle, as these orbits are not listed in NASA Contractor Report 3501) *Albedo: ~0.18-0.26 *Block Abundance: 5-26% *Fine-Component Thermal Inertia: 5-9 cgs units This region consists of bright deposits similar to those described by Edgett et al. [3], that also lie within a prominent dark albedo region. These deposits are flat-lying, to such a degree that they ramp against topography rather than draping over it. This led Edgett and Parker [4] to suggest that they may be subaqueous sediments, possibly lacustrine or marine evaporates, laid down sometime from the late Noachian to middle Hesperian (age determination pending crater counts). A contact between this material and elevated, dissected highlands to the south was identified [4], and this is described by Edgett et al. [3]. Our desire in proposing this landing site is to sample the edge of this deposit where it has been exposed through etching, presumably Eolian deflation (the deposit, though in the highlands, is itself only moderately cratered). This should enable access to in situ stratigraphy. The actual landing site will be selected where slopes are not expected to be steep, such that the rover itself should be able to traverse them and sample layered materials on the way, either up or down the slope. Perhaps due to uncertainties at this time as to the friability or meter-scale roughness of the deposit, it might make sense to place the landing ellipse on the exhumed highland surface adjacent to the deposit rather than landing on it and driving downslope. This should also enable imaging the margin for evidence of layering should it prove too difficult to climb. A target ellipse on the highland surface should also allow Athena access to ancient Noachian highland materials, particularly if placed near crater ejecta or an inlier of knobby material. Secondary Landing Site: Southern Elysium Planitia (Proposed by T. J. Parker) Vital Statistics: *Latitude, Longitude: 1.5-3.5°S, 195-198°W. *Elevation (Viking): -1.0 km. *Viking Orbiter Image coverage: Excellent coverage by 15-25 m/pixel images (orbit 725). Possible stereo coverage between images from beginning and end of orbit that overlap (probably small parallax angle, as these orbits are not listed in [5]) *Albedo: ~0.27-0.28 *Block Abundance: 4-7% *Fine-Component Thermal Inertia: ~3 cgs units This region consists of eroded knobby material, probably of Noachian age, though much of the crater population has been destroyed, that is onlapped at a sharp contact by an extensive plains unit in southern Elysium Planitia that is Amazonian in age. The plains materials have been attributed to unusually low-viscosity flood lavas [6] from fissures south of the Elysium volcanic rise, or to lacustrine material associated with a large, Amazonian lake at the source of Marte Vallis [7]. Parker and Schenk [8] presented evidence in support of the latter interpretation, though they attributed the putative shore morphology to an embayment of a northern plains ocean into the southern Elysium region. Detailed examination of the margin of the deposit, showing erosion, not simply burial, of small crater rims and fluidized ejecta blankets, also points to lacustrine or marine sedimentation rather than volcanic plains burial. The plains surface exhibits a "crusty" appearance that many researchers have attributed to pressure ridges in lava flows. In a lacustrine context, they also resemble pressure ridges in desiccated evaporite deposits and salt-rimmed pools (now dry) similar in scale and morphology to spectacular, hundred meter-scale pool rims in alkaline Lake Natron, East African Rift. The eroded highland margin surface adjacent to these plains appears to be fairly smooth, even at 15 m/pixel. Isolated knob inliers are scattered from a few kilometers to several tens of kilometers apart. Heights of the knobs have not been measured yet but, based on experience with similar features in the Pathfinder landing ellipse, are probably typically on the order of several tens of meters high and smaller, though some of the largest knobs in the region are probably up to a few hundred meters high. Two craters larger than a kilometer in diameter, with fluidized ejecta deposits, lie nearby the proposed landing site. Very high-resolution images from MOC should help to determine whether a landing site navigable by the Athena rover could be placed in this region. The space between knobs and craters is large enough to enable placement of a target landing ellipse between them but still provide access to one or more of them and to the margin of the Elysium plains material. Post-2001 Mars Surveyor Landing Site: Argyre Planitia (Proposed by T. J. Parker) Vital Statistics: *Latitude, Longitude: 55-56°S, 41-43°W. *Elevation (Viking): 1.0 km. *Viking Orbiter Image coverage: Excellent coverage by 40 m/pixel images (orbits 567B, 568B, 569B). Excellent stereo coverage with large parallax angles over the entire landing site region, and much of central and southern Argyre. *Albedo: ~0.23â0.24 *Block Abundance: No data *Fine-Component Thermal Inertia: No data The floors of both the Argyre and Hellas basins contain etched layered materials that are probably thick accumulations of channel or lacustrine sediments [9, 10]. The deposits in Hellas are much more eroded than those in Argyre, and Hellas lacks a channel outlet. Argyre is unique in that Uzboi Vallis flowed out of the basin, requiring overflow of a standing body of water within Argyre [11]. This makes it the largest impact basin on Mars with channels both draining into it and flowing out from it. Hellas' channels may be catastrophic flood channels, whereas Argyre was fed by modest-scale valley networks, though the outlet at Uzboi Vallis was a catastrophic flood. Highland craters and basins of this kind should be high-priority landing targets for missions intended to focus on the search for either prebiotic organic materials or even simple fossil microorganisms. Basins with internally-draining valley networks should be preferred over flood channels, as they could have provided the long-term influx of water favorable to the origin of life. (Catastrophic floods are not conducive to fossil preservation, due to their very short durations and high transportation energies). They also afford an opportunity to study the evolution of the planet's climate and volatiles during the period of time between the late Noachian and early Hesperian, when a drastic change from a proposed early warm, wet climate to one more closely resembling the modern environment is thought to have occurred. Large basins of this type are better targets than smaller ones, because the local environment would be less susceptible to freezing or drying caused by large swings in climate. REFERENCES: [1] P. Christensen (1986) Icarus 68: 217-238. [2] L. K. Pleskot and E. D. Miner (1981) Icarus 45: 179-201. [3] K. S. Edgett et al. (1998) this volume. [4] K. S. Edgett and T. J. Parker (1997) GRL 24: 2897-2900. [5] K. R. Blasius et al. (1982) NASA Cont. Rept. No. 3501. [6] J. B. Plescia (1990) Icarus 88: 465-490. [7] D. H. Scott and M. G. Chapman (1991) Proc. LPSC XXI: 669-677. [8] T. J. Parker and P. M. Schenk (1995) LPSC XXVI, 2p. [9] T. J. Parker (1994) Ph.D., Univ. of So. Cal., 200p. [10] J. M. Moore and K. S. Edgett (1993) GRL 20: 1599-1602. [11] T. J. Parker and D. S. Gorsline (1991) LPSC XXII: 1033-1034.

Laboratory Measurements of Oxygen Gas Release from Basaltic Minerals Exposed to UV- Radiation: Implications for the Viking Gas Exchange Experiments

NASA Astrophysics Data System (ADS)

Hurowitz, J. A.; Yen, A. S.

2007-12-01

The biology experiments onboard the Viking Landers determined that the Martian soils at Chryse and Utopia Planitia contain an unknown chemical compound of a highly oxidizing nature. The Gas Exchange Experiments (GEx) demonstrated that the humidification of a 1-cc Martian soil sample resulted in the production of as much as 790 nanomoles of oxygen gas. Yen et al. (2000) have provided experimental evidence that superoxide radicals can be generated on plagioclase feldspar (labradorite) grain surfaces by exposure to ultraviolet (UV) light in the presence of oxygen gas. Adsorbed superoxide radicals are thought to react readily with water vapor, and produce oxygen gas in quantities sufficient to explain the Viking GEx results. Direct evidence for the formation of oxygen gas, however, was not provided in the experiments of Yen et al (2000). Accordingly, the motivation of this study is to determine whether superoxide radicals adsorbed on labradorite surfaces are capable of producing oxygen gas upon exposure to water vapor. We have constructed an experimental apparatus that is capable of monitoring oxygen gas release from basaltic mineral powders that have been exposed to UV-radiation under Martian atmospheric pressure conditions. The apparatus consists of a stainless-steel vacuum chamber with a UV- transparent window where sample radiation exposures are performed. The vacuum chamber has multiple valved ports for injection of gases and water vapor. The vacuum chamber is connected via a precision leak valve to a quadrupole mass spectrometer, which measures changes in the composition of the headspace gases over our mineral samples. We will report on the results of our experiments, which are aimed at detecting and quantifying oxygen gas release from UV-exposed basaltic mineral samples using this new experimental facility. These results will further constrain whether superoxide ions adsorbed on mineral surfaces provide a viable explanation for the Viking GEx results, which have been of considerable controversy in the roughly three decades since the measurements were first made.

Utopia Providing Trusted Social Network Relationships within an Un-trusted Environment

NASA Astrophysics Data System (ADS)

Gauvin, William; Liu, Benyuan; Fu, Xinwen; Wang, Jie

This paper introduces an unobtrusive method and distributed solution set to aid users of on-line social networking sites, by creating a trusted environment in which every member has the ability to identify each other within their private social network by name, gender, age, location, and the specific usage patterns adopted by the group. Utopia protects members by understanding how the social network is created and the specific aspects of the group that make it unique and identifiable. The main focus of Utopia is the protection of the group, and their privacy within a social network from predators and spammers that characteristically do not fit within the well defined usage boundaries of the social network as a whole. The solution set provides defensive, as well as offensive tools to identify these threats. Once identified, client desktop tools are used to prevent these predators from further interaction within the group. In addition, offensive tools are used to determine the origin of the predator to allow actions to be taken by automated tools and law enforcement to alleviate the threat.

Evidence for Recent Liquid Water on Mars: 'Dry' Processes on One Slope; 'Wet' Processes on Another

NASA Technical Reports Server (NTRS)

2000-01-01

[figure removed for brevity, see original site] [figure removed for brevity, see original site]

How can martian gullies--thought to be caused in part by seepage and runoff of liquid water--be distinguished from the more typical, 'dry' slope erosion processes that also occur on Mars? For one thing, most--though not all--of the gully landforms occur on slopes that face away from the martian equator and toward the pole. For another, slopes that face toward the equator exhibit the same types of features as seen on nearly every other non-gullied slope on Mars.

The example shown here comes from northwestern Elysium Planitia in the martian northern hemisphere. The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) high resolution view (A, left) shows a portion of a 10 kilometer-(6.2 mi)-diameter meteor impact crater at a resolution of about 9 meters (29.5 ft) per pixel. The crater is shown in the context image (B, middle). The north-facing (or, pole-ward) slope in the MOC view is shadowed because sunlight illuminates the scene from the lower left. In this shadowed area, a series of martian gullies--defined by their erosional alcoves, deep channels, and apron deposits--are seen. On the sunlit south-facing (or equator-ward) slope, a scene more typical of most martian impact craters is present--the upper slopes show layered bedrock, the lower slopes show light-toned streaks of dry debris that has slid down the slope forming talus deposits that are distinctly different from the lobe-like form of gully aprons. The picture in (C) has been rotated so that the two slopes--one with gullies (right) and one without (left)--can be compared.

The crater is located at 36.7oN, 252.3oW. The MOC image was acquired in November 1999 and covers an area 3 km (1.9 mi) wide by 14 km (8.7 mi) long; north is toward the upper right (in A) and it is illuminated by sunlight from the lower left. The Viking 1 orbiter context image (B) was obtained in 1978 and is illuminated from the left; north is up. The MOC image has been rotated in the Explanatory Figure (C) such that north is toward the upper left, illumination is from the lower right.

Visible and Near-Infrared Spectroscopy of Hephaestus Fossae Cratered Cones, Mars

NASA Astrophysics Data System (ADS)

Dapremont, A.; Wray, J. J.

2017-12-01

Hephaestus Fossae are a system of sub-parallel fractures on Mars (> 500 km long) interpreted as near-surface tensional cracks [1]. Images of the Martian surface from the High Resolution Imaging Science Experiment have revealed cratered cones within the Hephaestus Fossae region. A volcanic origin (cinder/tuff cones) has been proposed for these features based on morphometric measurements and fine-scale surface characteristics [2]. In an effort to further constrain the origin of these cones as the products of igneous or sedimentary volcanism, we use data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). We take advantage of CRISM's S (0.4 - 1.0 microns) and L (1.0 - 3.9 microns) detector wavelength ranges to investigate the presence or absence of spectral signatures consistent with previous identifications of igneous and mud volcanism products on Mars [3,4]. Hephaestus Fossae cratered cone rims exhibit a consistent nanophase ferric oxide signature. We also identify ferrous phases and 3-micron absorptions (attributed to fundamental vibrational stretch frequencies in H2O) on the crater rims of several cones. Mafic signatures on cratered cone rims support an igneous provenance for these features. The 3-micron absorptions are consistent with the presence of structurally bound or adsorbed water. Our CRISM observations are similar to those of small edifice features in Chryse Planitia, which were interpreted as mud volcanism products based on their enrichment of nanophase ferric minerals and 3-micron absorptions on summit crater rims [3]. Hydrothermal activity was invoked for a Coprates Chasma pitted cone (scoria/tuff cone) based on CRISM identification of partially dehydrated opaline silica, which we do not observe in Hephaestus Fossae [4]. Our spectral observations are more consistent with mud volcanism, but we do not definitively rule out an igneous volcanic origin for the cones in our study region. We demonstrate that VNIR spectroscopy is a valuable tool in developing criteria to determine the origin (igneous/sedimentary/periglacial) of cone features on Mars. [1] Skinner and Tanaka (2007) Icarus 186: 41-59. [2] Dundas et al (2007) LPSC XXXVIII Abs #2116. [3] Komatsu et al (2016) Icarus 268: 56-75. [4] Brož et al (2017) Earth and Planetary Sci Letters 473: 122-130.

Zeolite Formation and Weathering Processes in Dry Valleys of Antartica: Martian Analogs

NASA Technical Reports Server (NTRS)

Gibson, E. K., Jr.; Wentworth, S. J.; McKay, D. S.; Socki, R. A.

2004-01-01

Terrestrial weathering processes in cold-desert climates such as the Dry Valleys of Antarctica may provide an excellent analog to chemical weathering and diagenesis of soils on Mars. Detailed studies of soil development and the chemical and mineralogical alterations occurring within soil columns in Wright Valley, Antarctica show incredible complexity in the upper meter of soil. Previous workers noted the ice-free Dry Valleys are the best terrestrial approximations to contemporary Mars. Images returned from the Pathfinder and Spirit landers show similarities to surfaces observed within the Dry Valleys. Similarities to Mars that exist in these valleys are: mean temperatures always below freezing (-20 C), no rainfall, sparse snowfall-rapidly removed by sublimation, desiccating winds, diurnal freeze-thaw cycles (even during daylight hours), low humidity, oxidative environment, relatively high solar radiation and low magnetic fields . The Dry Valley soils contain irregular distributions and low abundances of soil microorganisms that are somewhat unusual on Earth. Physical processes-such as sand abrasion-are dominant mechanisms of rock weathering in Antarctica. However, chemical weathering is also an important process even in such extreme climates. For example, ionic migration occurs even in frozen soils along liquid films on individual soil particles. It has also been shown that water with liquid-like properties is present in soils at temperatures on the order of approx.-80 C and it has been observed that the percentage of oxidized iron increases with increasing soil age and enrichments in oxidized iron occurs toward the surface. The presence of evaporates is evident and appear similar to "evaporite sites" within the Pathfinder and Spirit sites. Evaporites indicate ionic migration and chemical activity even in the permanently frozen zone. The presence of evaporates indicates that chemical weathering of rocks and possibly soils has been active. Authogenic zeolites have been identified within the soil columns because they are fragile; i.e. they are euhedral, unabraded, and unfractured, strongly suggesting in situ formation. Their presence in Antarctic samples is another indication that diagenic processes are active in cold-desert environments. The presence of zeolites, and other clays along with halites, sulfates, carbonates, and hydrates are to be expected within the soil columns on Mars at the Gusev and Isidis Planitia regions. The presence of such water-bearing minerals beneath the surface supplies one of the requirements to support biological activity on Mars.

Ambrosius Holbein's memento mori map for Sir Thomas More's Utopia. The meanings of a masterpiece of early sixteenth century graphic art.

PubMed

Bishop, M

2005-07-23

This paper describes how, and asks why, the Renaissance artist Ambrosius Holbein hid a skull within the overall design of his woodcut map of Sir Thomas More's Utopia. (Fig. 2) This map was prepared for the 1518 Froben edition of the book, and was probably commissioned by Erasmus of Rotterdam. Its identification now is made easier by the habits of interpretation with which all dentists are equipped thanks to their skill in dental radiology, and by the recognition of teeth appearing in an unlikely disguise.

Geologic Mapping of V-19

NASA Technical Reports Server (NTRS)

Martin, Paula; Stofan, E. R.; Guest, J. E.

2010-01-01

A geologic map of the Sedna Planitia (V-19) quadrangle is being completed at 1:5,000,000 scale as part of the NASA Planetary Geologic Mapping Program, and will be submitted for review by September 2010. Overview: The Sedna Planitia quadrangle (V-19) extends from 25 N - 50 N latitude, 330 - 0 longitude. The quadrangle contains the northernmost portion of western Eistla Regio and the Sedna Planitia lowlands. Sedna Planitia consists of low-lying plains units, with numerous small volcanic edifices including shields, domes and cones. The quadrangle also contains several tholi, the large flowfield Neago Fluctus, the Manzan-Gurme Tesserae, and Zorile Dorsa and Karra-mahte Fossae which run NW-SE through the southwestern part of the quadrangle. There are six coronae in the quadrangle (Table 1), the largest of which is Nissaba (300 km x 220 km), and there are fourteen impact craters (Table 2). The V-19 quadrangle contains a variety of mappable volcanic landforms including two shield volcanoes (Evaki Tholus and Toci Tholus) and the southern portion of a large flow field (Neago Fluctus). A total of sixteen units associated with volcanoes have been mapped in this quadrangle, with multiple units mapped at Sif Mons, Sachs Patera and Neago Fluctus. An oddly textured, radarbright flow is also mapped in the Sedna plains, which appears to have originated from a several hundred kilometer long fissure. The six coronae within V-19 have a total of eighteen associated flow units. Several edifice fields are also mapped, in which the small volcanic edifices both predate and postdate the other units. Impact crater materials are also mapped.

The Origin of the Terra Meridiani Sediments: Volatile Transport and the Formation of Sulfate Bearing Layered Deposits on Mars

NASA Technical Reports Server (NTRS)

Niles, P.B.

2008-01-01

The chemistry, sedimentology, and geology of the Meridiani sedimentary deposits are best explained by eolian reworking of the sublimation residue of a large scale ice/dust deposit. This large ice deposit was located in close proximity to Terra Meridiani and incorporated large amounts of dust, sand, and SO2 aerosols generated by impacts and volcanism during early martian history. Sulfate formation and chemical weathering of the initial igneous material is hypothesized to have occurred inside of the ice when the darker mineral grains were heated by solar radiant energy. This created conditions in which small films of liquid water were created in and around the mineral grains. This water dissolved the SO2 and reacted with the mineral grains forming an acidic environment under low water/rock conditions. Subsequent sublimation of this ice deposit left behind large amounts of weathered sublimation residue which became the source material for the eolian process that deposited the Terra Meridiani deposit. The following features of the Meridiani sediments are best explained by this model: The large scale of the deposit, its mineralogic similarity across large distances, the cation-conservative nature of the weathering processes, the presence of acidic groundwaters on a basaltic planet, the accumulation of a thick sedimentary sequence outside of a topographic basin, and the low water/rock ratio needed to explain the presence of very soluble minerals and elements in the deposit. Remote sensing studies have linked the Meridiani deposits to a number of other martian surface features through mineralogic similarities, geomorphic similarities, and regional associations. These include layered deposits in Arabia Terra, interior layered deposits in the Valles Marineris system, southern Elysium/Aeolis, Amazonis Planitia, and the Hellas basin, Aram Chaos, Aureum Chaos, and Ioni Chaos. The common properties shared by these deposits suggest that all of these deposits share a common formation process which must have acted over a large area of Mars. The results of this study suggest a mechanism for volatile transport on Mars without invoking an early greenhouse. They also imply a common formation mechanism for most of the sulfate minerals and layered deposits on Mars, which explains their common occurrence.

Geometry of Thrust Faults Beneath Amenthes Rupes, Mars

NASA Technical Reports Server (NTRS)

Vidal, A.; Mueller, K. M.; Golombek, M. P.

2005-01-01

Amenthes Rupes is a 380 km-long lobate fault scarp located in the eastern hemisphere of Mars near the dichotomy boundary. The scarp is marked by about 1 km of vertical separation across a northeast dipping thrust fault (top to the SW) and offsets heavily-cratered terrain of Late Noachian age, the visible portion of which was in place by 3.92 Ga and the buried portion in place between 4.08 and 4.27 Ga. The timing of scarp formation is difficult to closely constrain. Previous geologic mapping shows that near the northern end of Amenthes Rupes, Hesperian age basalts terminate at the scarp, suggesting that fault slip predated the emplacement of these flows at 3.69 to 3.9 Ga. Maxwell and McGill also suggest the faulting ceased before the final emplacement of the Late Hesperian lavas on Isidis Planitia. The trend of the faults at Amenthes, like many thrust faults at the dichotomy boundary, parallels the boundary itself. Schultz and Watters used a dislocation modeling program to match surface topography and vertical offset of the scarp at Amenthes Rupes, varying the dip and depth of faulting, assuming a slip of 1.5 km on the fault. They modeled faulting below Amenthes Rupes as having a dip of between 25 and 30 degrees and a depth of 25 to 35 km, based on the best match to topography. Assuming a 25 degree dip and surface measurements of vertical offset of between 0.3 and 1.2 km, Watters later estimated the maximum displacement on the Amenthes Rupes fault to be 2.90 km. However, these studies did not determine the geometry of the thrust using quantitative constraints that included shortening estimates. Amenthes Rupes deforms large preexisting impact craters. We use these craters to constrain shortening across the scarp and combine this with vertical separation to infer fault geometry. Fault dip was also estimated using measurements of scarp morphology. Measurements were based on 460 m (1/128 per pixel) digital elevation data from the Mars Orbiter Laser Altimeter (MOLA), an instrument on the Mars Global Surveyor (MGS) satellite.

Using THEMIS thermal infrared observations of rays from Corinto crater to study secondary crater formation on Mars

NASA Astrophysics Data System (ADS)

Williams, J. P.

2017-12-01

Corinto crater (16.95°N, 141.72°E), a 13.8 km diameter crater in Elysium Planitia, displays dramatic rays in Mars Odyssey's Thermal Emission Imaging System (THEMIS) nighttime infrared imagery where high concentrations of secondary craters have altered the thermophysical properties of the martian surface. The THEMIS observations provide a record of secondary crater formation in the region and ray segments are identified up to 2000 km ( 145 crater radii) distance [1][2]. Secondary craters are likely to have the largest influence on model surfaces ages between 0.1 to a few Myr as there is the potential for one or two sizeable craters to project secondary craters onto those surfaces and thus alter the crater size-frequency distribution (CSFD) with an instantaneous spike in crater production [3]. Corinto crater is estimated to be less than a few Ma [4] placing the formation of its secondaries within this formative time period. Secondary craters superposed on relatively young impact craters that predate Corinto provide observations of the secondary crater populations. Crater counts at 520 and 660 km distance from Corinto (38 and 48 crater radii respectively), were conducted. Higher crater densities were observed within ray segments, however secondary craters still influenced the CSFD where ray segments were not apparent, resulting in steepening in the CSFD. Randomness analysis confirms an increase in clustering as diameters decrease suggesting an increasing fraction of secondary craters at smaller diameters, both within the ray and outside. The counts demonstrate that even at nearly 50 crater radii, Corinto secondaries still influence the observed CSFD, even outside of any obvious rays. Crater populations used to derive model ages on many geologically young regions on Mars, such as glacial and periglacial landforms related to obliquity excursions that occur on 106 - 107 yr cycles, should be used cautiously and analyzed for any evidence, either morphologic or statistical, for secondary cratering that may potentially influence the derived age. [1] Williams et al. (2017) MAPS, in press. [2] Bloom et al. (2014) Mars 8th, #1289. [3] Hartmann and Daubar (2017), MAPS, 52, 493- 510. [4] Hundal et al. (2017), LPSC, #1726.

Stickney Crater on Phobos and some other outstanding planetary depressions as features of crustal wave interference origin

NASA Astrophysics Data System (ADS)

Kochemasov, G. G.

2011-10-01

Some not fully understood (enigmatic) large planetary depressions and geoid minima on planets and satellites are better understood as regular wave woven features, not random large impacts [1]. A main reason for this is their similar tectonic position in a regular sectoral network produced by interfering crossing standing waves warping any celestial body. These waves arise in the bodies due to their movements in keplerian elliptical orbits with changing accelerations. The fundamental wave1 produces universal tectonic dichotomy, its first overtone wave2 superposes on it sectoring - a regular network of risen and fallen blocks [2, 3]. Thus, deeply subsided sectoral blocks are formed on uplifted highland segments -hemispheres [1]. Examples of this pattern are shown in Fig. 1 to 8 on various globes and irregular bodies. The Moon - the SPA basin, Earth - Indian geoid min imum, Phobos - Stickney Crater, Miranda - an ovoid, Phoebe - a sector, Mars - Hellas Planitia, Lutetia - a deep sector indentation. Fig. 9 - a geometrical model of dichotomy and sectors format ion by wave interference.

Geologic Map of the Snegurochka Planitia Quadrangle (V-1): Implications for the Volcanic History of the North Polar Region of Venus

NASA Technical Reports Server (NTRS)

Hurwitz, D. M.; Head, J. W.

2010-01-01

Geologic mapping of Snegurochka Planitia (V-1) reveals a complex stratigraphy of tectonic and volcanic features that can provide insight into the geologic history of Venus and Archean Earth [1,2], including 1) episodes of both localized crustal uplift and mantle downwelling, 2) shifts from local to regional volcanic activity, and 3) a shift back to local volcanic activity. We present our interpretations of the volcanic history of the region surrounding the north pole of Venus and explore how analysis of new data support our interpretations

Triggering a Wet Climate on Mars: The Role of Outflow Channels in Martian Water Cycles

NASA Astrophysics Data System (ADS)

Santiago, D.; Asphaug, E. I.; Colaprete, A.

2011-12-01

The triggering of a robust water cycle on Mars has been hypothesized to be caused by gigantic flooding events evidenced by outflow channels. Here we use the Ames Mars General Circulation Model (MGCM) to study how these presumably abrupt eruptions of water (Carr,1996) affected the climate of Mars. We model where the water ultimately went as part of a transient hydrologic cycle. Chryse Planitia, east of Tharsis, has evidence for multiple water outflow channels. One of the largest channels is Ares Valles, which was carved by floods with estimated water volumes of order 10^5 km^2 (Andrews-Hanna, 2007 & Carr, 1996). Outflow discharge rate estimates range from 10^6 to 10^7 m^3/seconds or greater (Andrews-Hanna & Phillips, 2007, Harrison & Grimm, 2008). Studies suggest that outflow channels formed with smaller, successive floods instead of a single large flood (Wilson, et al.,2004). Warner et al. (2009) suggest up to six outflow events for the formation of Ares Valles, while estimates for another large outflow, Kasei Valles, might have been flooded by over two thousand floods with a total water volume of 5.5 x 10^5 km^3 (Harrison & Grimm, 2008). By adding water to the surface of Mars at the given outflow rate, as an expanding one-layer lake, we are able to study quantitatively how these outflow events influenced Mars climate, particularly the hydrologic cycle. In particular: Could sudden introductions of large amounts of water on the Martian surface lead to a new equilibrated water cycle? Can we tie certain fluvial surface features to transient or sustained water cycles? What are the roles of water vapor and water ice clouds to sudden changes in the water cycle on Mars? How are radiative feedbacks involved with this? What is the ultimate fate of the outflow water? This work uses the NASA Ames MGCM version 2.1 and other schemes that are part of the NASA Ames MGCM suite of tools. Various versions of the MGCM developed at Ames have been used extensively to examine dust and volatile distributions on Mars (e.g., Kahre et al., 2006, 2008). The MGCM 2.1 currently has a well-developed water ice cloud formation scheme (Montmessin et al., 2002, 2004a), which includes calculation of cloud particle concentrations, nucleation, growth, and gravitational sedimentation. For examining the effect of a large water outflow on the climate of Mars, we include water tracers, with an advanced cloud particle scheme Preliminary results suggest that water may have been transported globally for years post-outflow. Post-outflow water cloud formation increases dramatically, with water ice clouds and water vapor potentially transporting water globally. The global mass of water vapor and of water ice clouds increases substantially, with the post-outflow patterns settling into annual cycles, with increasing water entering the atmosphere from the surface over time. Future work will examine the radiative effects of the water vapor and water ice clouds, and the longer-term persistence of a new hydrological or climate regime Detailed comparisons of post-outflow precipitation locations with fluvial features on Mars will be done.

Investigating Mars: Kaiser Crater Dunes

NASA Image and Video Library

2018-02-02

This is a false color image of Kaiser Crater. In this combination of filters "blue" typically means basaltic sand. This VIS image crosses 3/4 of the crater and demonstrates how extensive the dunes are on the floor of Kaiser Crater. Kaiser Crater is located in the southern hemisphere in the Noachis region west of Hellas Planitia. Kaiser Crater is just one of several large craters with extensive dune fields on the crater floor. Other nearby dune filled craters are Proctor, Russell, and Rabe. Kaiser Crater is 207 km (129 miles) in diameter. The dunes are located in the southern part of the crater floor. The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 66602 Latitude: -47.0551 Longitude: 19.446 Instrument: VIS Captured: 2016-12-18 21:42 https://photojournal.jpl.nasa.gov/catalog/PIA22265

Scaly-skinned Mars

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site]

The style of erosion along the highlands-lowlands boundary of southern Elysium Planitia has produced a strange pattern of troughs that look like the skin of a reptile. In reality, a very clear process of landscape degradation is evident in this image. Some process has produced polygon-shaped troughs that create zones of weakness in the uppermost crust. It is likely that wind-blown particles deepen and widen the troughs, producing isolated knobs and mesas. Ultimately, the erosional reworking of the landscape is so complete that all signs of the upper layer are removed, leaving the smooth lowland surface to the north.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Quantitative characterization of the small-scale fracture patterns on the plains of Venus

NASA Technical Reports Server (NTRS)

Sammis, Charles G.; Bowman, David D.

1995-01-01

The objectives of this research project were to (1) compile a comprehensive database of the occurrence of regularly spaced kilometer scale lineations on the volcanic plains of Venus in an effort to verify the effectiveness of the shear-lag model developed by Banerdt and Sammis (1992), and (2) develop a model for the formation of irregular kilometer scale lineations such as typified in the gridded plains region of Guinevere Planitia. Attached to this report is the paper 'A Tectonic Model for the Formation of the Gridded Plains on Guinevere Planitia, Venus, and Implications for the Elastic Thickness of the Lithosphere'.

Geologic Map of the Snegurochka Planitia Quadrangle (V-1): Implications for Tectonic and Volcanic History of the North Polar Region of Venus

NASA Technical Reports Server (NTRS)

Hurwitz, D. M.; Head, J. W.

2009-01-01

Geologic mapping of Snegurochka Planitia (V-1) reveals a complex stratigraphy of tectonic and volcanic features that can provide insight into the geologic history of Venus and Archean Earth [1,2], including 1) episodes of both localized crustal uplift and mantle downwelling, 2) shifts from local to regional volcanic activity, and 3) a shift back to local volcanic activity. We present our progress in mapping the spatial and stratigraphic relationships of material units and our initial interpretations of the tectonic and volcanic history of the region surrounding the north pole of Venus

Small-scale volcanoes on Mars: distribution and types

NASA Astrophysics Data System (ADS)

Broz, Petr; Hauber, Ernst

2015-04-01

Volcanoes differ in sizes, as does the amount of magma which ascends to a planetary surface. On Earth, the size of volcanoes is anti-correlated with their frequency, i.e. small volcanoes are much more numerous than large ones. The most common terrestrial volcanoes are scoria cones (

Automated forward mechanical modeling of wrinkle ridges on Mars

NASA Astrophysics Data System (ADS)

Nahm, Amanda; Peterson, Samuel

2016-04-01

One of the main goals of the InSight mission to Mars is to understand the internal structure of Mars [1], in part through passive seismology. Understanding the shallow surface structure of the landing site is critical to the robust interpretation of recorded seismic signals. Faults, such as the wrinkle ridges abundant in the proposed landing site in Elysium Planitia, can be used to determine the subsurface structure of the regions they deform. Here, we test a new automated method for modeling of the topography of a wrinkle ridge (WR) in Elysium Planitia, allowing for faster and more robust determination of subsurface fault geometry for interpretation of the local subsurface structure. We perform forward mechanical modeling of fault-related topography [e.g., 2, 3], utilizing the modeling program Coulomb [4, 5] to model surface displacements surface induced by blind thrust faulting. Fault lengths are difficult to determine for WR; we initially assume a fault length of 30 km, but also test the effects of different fault lengths on model results. At present, we model the wrinkle ridge as a single blind thrust fault with a constant fault dip, though WR are likely to have more complicated fault geometry [e.g., 6-8]. Typically, the modeling is performed using the Coulomb GUI. This approach can be time consuming, requiring user inputs to change model parameters and to calculate the associated displacements for each model, which limits the number of models and parameter space that can be tested. To reduce active user computation time, we have developed a method in which the Coulomb GUI is bypassed. The general modeling procedure remains unchanged, and a set of input files is generated before modeling with ranges of pre-defined parameter values. The displacement calculations are divided into two suites. For Suite 1, a total of 3770 input files were generated in which the fault displacement (D), dip angle (δ), depth to upper fault tip (t), and depth to lower fault tip (B) were varied. A second set of input files was created (Suite 2) after the best-fit model from Suite 1 was determined, in which fault parameters were varied with a smaller range and incremental changes, resulting in a total of 28,080 input files. RMS values were calculated for each Coulomb model. RMS values for Suite 1 models were calculated over the entire profile and for a restricted x range; the latter shows a reduced RMS misfit by 1.2 m. The minimum RMS value for Suite 2 models decreases again by 0.2 m, resulting in an overall reduction of the RMS value of ~1.4 m (18%). Models with different fault lengths (15, 30, and 60 km) are visually indistinguishable. Values for δ, t, B, and RMS misfit are either the same or very similar for each best fit model. These results indicate that the subsurface structure can be reliably determined from forward mechanical modeling even with uncertainty in fault length. Future work will test this method with the more realistic WR fault geometry. References: [1] Banerdt et al. (2013), 44th LPSC, #1915. [2] Cohen (1999), Adv. Geophys., 41, 133-231. [3] Schultz and Lin (2001), JGR, 106, 16549-16566. [4] Lin and Stein (2004), JGR, 109, B02303, doi:10.1029/2003JB002607. [5] Toda et al. (2005), JGR, 103, 24543-24565. [6] Okubo and Schultz (2004), GSAB, 116, 597-605. [7] Watters (2004), Icarus, 171, 284-294. [8] Schultz (2000), JGR, 105, 12035-12052.

Geologic history of the polar regions of Mars based on Mars Global survey data. I. Noachian and Hesperian Periods

USGS Publications Warehouse

Tanaka, K.L.; Kolb, E.J.

2001-01-01

During the Noachian Period, the south polar region of Mars underwent intense cratering, construction of three groups of volcanoes, widespread contractional deformation, resurfacing of low areas, and local dissection of valley networks; no evidence for polar deposits, ice sheets, or glaciation is recognized. South polar Hesperian geology is broadly characterized by waning impacts, volcanism, and tectonism. Emplacement of the polar Dorsa Argentea Formation (DAF) occurred during the Hesperian Period. Mars Orbiter Laser Altimeter topographic data and Mars Orbiter Camera images elucidate stratigraphic, morphologic, and topographic relations, permitting the dividing of the DAF into eight members, which surround and underlie about half of the Amazonian south polar layered deposits. The lobate fronts and lack of typical volcanic-flow morphology of the six plains units indicate that they may be made up of debris flows. We think that these flows, tens of meters to 200 m thick, may have originated by the discharge of huge volumes of slurry fluidized by ground water or liquid CO2, perhaps triggered by local impacts, igneous activity, or basal melting beneath polar deposits. The cavi and rugged members include irregular depressions that penetrate the subsurface; some of the pits have raised rims. The depressions may have formed by collapse due to expulsion of subsurface material in which local explosive activity built up the raised rims. Further, smaller eruptions of volatile-rich material may have resulted in narrow, sinuous channel deposits within aggrading fine-grained unconsolidated material perhaps produced by gaseous discharge of subsurface volatiles; preferential erosion of the latter material could have produced the Dorsa Argentea-type ginuous ridges associated mainly with the DAF. Alternatively, the ridges may be eskers, but the lack of associated glacial and fluvial morphologies casts doubt on this interpretation. The knobby, degraded materials forming Scandia Colles may represent the only Noachian geologic record exposed in the north polar region. Most of the north polar region was buried by water- or debris-ocean sediments during the Hesperian Period, originating from uplands areas and perhaps knobby terrains in the northern plains. The sediments either mantle or were deformed by wrinkle ridges radial and concentric to Utopia basin and concentric to northern Tharsis. Sources of stress probably included sediment loading in the northern plains and regional magmatic and loading activity at Tharsis. Polar layered deposits began piling up during the Early Amazonian or later. ?? 2001 Elsevier Science.

Geologic History of the Polar Regions of Mars Based on Mars Global Surveyor Data. I. Noachian and Hesperian Periods

NASA Astrophysics Data System (ADS)

Tanaka, Kenneth L.; Kolb, Eric J.

2001-11-01

During the Noachian Period, the south polar region of Mars underwent intense cratering, construction of three groups of volcanoes, widespread contractional deformation, resurfacing of low areas, and local dissection of valley networks; no evidence for polar deposits, ice sheets, or glaciation is recognized. South polar Hesperian geology is broadly characterized by waning impacts, volcanism, and tectonism. Emplacement of the polar Dorsa Argentea Formation (DAF) occurred during the Hesperian Period. Mars Orbiter Laser Altimeter topographic data and Mars Orbiter Camera images elucidate stratigraphic, morphologic, and topographic relations, permitting the dividing of the DAF into eight members, which surround and underlie about half of the Amazonian south polar layered deposits. The lobate fronts and lack of typical volcanic-flow morphology of the six plains units indicate that they may be made up of debris flows. We think that these flows, tens of meters to 200 m thick, may have originated by the discharge of huge volumes of slurry fluidized by ground water or liquid CO 2, perhaps triggered by local impacts, igneous activity, or basal melting beneath polar deposits. The cavi and rugged members include irregular depressions that penetrate the subsurface; some of the pits have raised rims. The depressions may have formed by collapse due to expulsion of subsurface material in which local explosive activity built up the raised rims. Further, smaller eruptions of volatile-rich material may have resulted in narrow, sinuous channel deposits within aggrading fine-grained unconsolidated material perhaps produced by gaseous discharge of subsurface volatiles; preferential erosion of the latter material could have produced the Dorsa Argentea-type sinuous ridges associated mainly with the DAF. Alternatively, the ridges may be eskers, but the lack of associated glacial and fluvial morphologies casts doubt on this interpretation. The knobby, degraded materials forming Scandia Colles may represent the only Noachian geologic record exposed in the north polar region. Most of the north polar region was buried by water- or debris-ocean sediments during the Hesperian Period, originating from uplands areas and perhaps knobby terrains in the northern plains. The sediments either mantle or were deformed by wrinkle ridges radial and concentric to Utopia basin and concentric to northern Tharsis. Sources of stress probably included sediment loading in the northern plains and regional magmatic and loading activity at Tharsis. Polar layered deposits began piling up during the Early Amazonian or later.

Recent Flood Volcanism on Mars: Implications for Climate Change, Layered Deposits, and Lava-Water Interactions

NASA Astrophysics Data System (ADS)

Keszthelyi, L.; McEwen, A.

2001-05-01

In many ways, the high-resolution imaging of volcanic features on Mars has been disappointing due to the significantly degraded state of the ancient surfaces. One major exception has been the recent volcanism in the Cerberus Plains and Amazonis Planitia (Keszthelyi et al., 2000). Crater counts suggest some lava surfaces are less than 10 Ma (Hartmann and Berman, 2000), though rapid burial and very recent exhumation would allow for somewhat older eruptions. Investigation of the platy-ridged portion of the 1783-1784 Laki flow field in Iceland revealed that these lava flows have a morphology unlike any in Hawaii. We have called this form of lava "rubbly pahoehoe" and find it in several terrestrial flood basalt settings (Keszthelyi and Thordarson, 2000). Rubbly pahoehoe on Iceland and Mars transitions into undisrupted inflated pahoehoe flows at their margins. These flows are hypothesized to form as surges in flow rate travel through large inflating sheet flows. This allows emplacement underneath a thick mobile insulating crust, permitting lava to travel great distances in a rapid but laminar manner. Thermal modeling suggests eruption rates on the order of 105 m3/s feeding these sheets of lava, a rate about an order of magnitude larger than typical for terrestrial flood basalt eruptions. These huge eruptions potentially have significant climatic implications. If the dissolved volatile content of the Martian flood lavas were similar to that of large terrestrial basaltic eruptions (Thordarson and Self, 1996; McSween et al., 2001) we would expect on the order of 300 Gt of highly acidic gas to be released. Simultaneously, several thousand cubic kilometers of highly vesicular basaltic ash should be produced. Further gas release and ash production would come from the rootless cone fields found on the lavas (Lanagan et al., submitted). The acid-laced ash may be deposited to form the Medussae Fossae Formation and perhaps other finely layered sedimentary deposits seen on Mars. There is evidence from MOC and MOLA that recent floods of both water and lava originated from Cerberus Rupes, a fracture system which has been active very recently (it cuts the young lavas). This may be the very best place on Mars to search for current geothermal activity. Keszthelyi et al. (2000) JGR 105, 15027-15049. Hartmann and Berman (2000) JGR, 105, 15011-15025. Thordarson and Self (1996) JVGR 74, 49-73. Keszthelyi and Thordarson, (2000) GSA Ann. Meet. Abst. #5293. McSween, et al. (2001), Nature 409, 487-490. Lanagan et al., (submitted) GRL.

Radar scattering properties of pancakelike domes on Venus

NASA Technical Reports Server (NTRS)

Ford, P. G.; Pettengill, G. H.

1992-01-01

Magellan radar images have disclosed the presence of a large number of almost perfectly circular domes, presumably of volcanic origin, in many regions of Venus several with diameters of 30 km or more. Their high degree of symmetry has permitted measurements of their shape, as determined by the Magellan altimeter to be compared with models of dome production from the eruption of high-viscosity magmas. In this work, we examine in detail the radar images of domes in Rusalka Planitia (2.8 deg S, 150.9 deg E) and Tinatin Planitia (12.2 deg N, 7.5 deg E), selected for their circular symmetry and apparent absence of modification due to large-scale slumping or tectonic rifting.

A record of igneous evolution in Elysium, a major martian volcanic province

PubMed Central

Susko, David; Karunatillake, Suniti; Kodikara, Gayantha; Skok, J. R.; Wray, James; Heldmann, Jennifer; Cousin, Agnes; Judice, Taylor

2017-01-01

A major knowledge gap exists on how eruptive compositions of a single martian volcanic province change over time. Here we seek to fill that gap by assessing the compositional evolution of Elysium, a major martian volcanic province. A unique geochemical signature overlaps with the southeastern flows of this volcano, which provides the context for this study of variability of martian magmatism. The southeastern lava fields of Elysium Planitia show distinct chemistry in the shallow subsurface (down to several decimeters) relative to the rest of the martian mid-to-low latitudes (average crust) and flows in northwest Elysium. By impact crater counting chronology we estimated the age of the southeastern province to be 0.85 ± 0.08 Ga younger than the northwestern fields. This study of the geochemical and temporal differences between the NW and SE Elysium lava fields is the first to demonstrate compositional variation within a single volcanic province on Mars. We interpret the geochemical and temporal differences between the SE and NW lava fields to be consistent with primary magmatic processes, such as mantle heterogeneity or change in depth of melt formation within the martian mantle due to crustal loading. PMID:28233797

Evidence for Regional Basin Formation in Early Post-Tessera Venus History: Geology of the Lavinia Planitia Area (V55)

NASA Technical Reports Server (NTRS)

Head, J. W.; Ivanov, M. A.

1995-01-01

On Venus, global topography shows the presence of highs and lows including regional highly deformed plateaus (tesserae), broad rifted volcanic rises, linear lows flanking uplands, and more equidimensional lowlands (e.g. Lavinia and Atalanta planitiae) Each of these terrain types on Venus has relatively distinctive characteristics, but origins are uncertain in terms of mode of formation, time of formation, and potential evolutionary links. There is a high level of uncertainty about the formation and evolution of lowlands on Venus. We have undertaken the mapping of a specific lowlands region of Venus to address several of these major questions. Using geologic mapping we have tried to establish: What is the sequence of events in the formation and evolution of large-scale equidimensional basins on Venus? When do the compressional features typical of basin interiors occur? What is the total volume of lava that occurs in the basins and is this similar to other non-basin areas? How much subsidence and downwarping has occurred after the last major plains units? WE have undertaken an analysis of the geology of the V55 Lavinia Planitia quadrangle in order to address many of these issues and we report on the results here.

No Mystery! Water Carved the Outflow Channels on Mars

NASA Astrophysics Data System (ADS)

Coleman, N.

2002-12-01

The enormous outflow channels of Chryse Planitia provide the best evidence that large amounts of water were once released onto the martian surface. The role of water has recently been challenged by the White Mars hypothesis, which claims that the channels were cut by CO2 gas-supported debris flows that also resurfaced the northern plains. Hoffman [Icarus, 2000] refers to a volumetric "misfit" between outburst channels and the chaos source zones. He explains that chaos collapse "...involves regolith alone which generates its own fluids from liquid CO2 and CO2-bearing ices within its own volume." Hoffman [LPSC 32, #1257] argues that release of liquid CO2 produced Aromatum Chaos, and a hypothetical energetic "jet" of gas and debris carved Ravi Vallis. He notes that water would have had to be locally recharged in many episodes to provide enough discharge to form the chaos and channel. However, these assertions appear incorrect because the fluid source was a distant surface impoundment, not local recharge. Carr [Water on Mars, 1996] describes a 400-km-long zone of subsidence that extends northward from Ganges Chasma to the source of Shalbatana Vallis. MOLA data reveal that this subsidence also extends eastward to Aromatum Chaos, the source of Ravi Vallis. The field relations show that a liquid-filled impoundment in Ganges Chasma drained northward via subterranean flowpaths to maintain surface flows in Shalbatana and Ravi Valles. The fact that the flows began at a surface impoundment virtually eliminates liquid CO2 as the flowing agent. Liquid CO2 would not be stable at the surface unless the atmospheric pressure exceeded 5 atm. A recent study by Stewart and Nimmo [JGR, in press] suggests that CO2 in liquid, solid, or clathrate form could not be preserved within the crust over geologic time. Liquid water is much closer to its stability field even on present-day Mars. Large outflow channels, such as Kasei and Tiu-Simud Valles, likely formed through the release of floodwaters dammed by ice and debris, analogous to the scabland flooding of eastern Washington. The water sources were probably ice-covered impoundments in ancestral Valles Marineris canyons. Subice volcanism was a possible source of heat to create liquid water. The former existence of transient water bodies near the surface can help to calibrate models of a volcanic-hydrologic climax during the Hesperian.

Petrologic Modeling of Magmatic Evolution in The Elysium Volcanic Province

NASA Astrophysics Data System (ADS)

Susko, D.; Karunatillake, S.; Hood, D.

2017-12-01

The Elysium Volcanic Province (EVP) on Mars is a massive expanse of land made up of many hundreds of lava flows of various ages1. The variable surface ages within this volcanic province have distinct elemental compositions based on the derived values from the Gamma Ray Spectrometer (GRS) suite2. Without seismic data or ophiolite sequences on Mars, the compositions of lavas on the surface provide some of the only information to study the properties of the interior of the planet. The Amazonian surface age and isolated nature of the EVP in the northern lowlands of Mars make it ideal for analyzing the mantle beneath Elysium during the most recent geologic era on Mars. The MELTS algorithm is one of the most commonly used programs for simulating compositions and mineral phases of basaltic melt crystallization3. It has been used extensively for both terrestrial applications4 and for other planetary bodies3,5. The pMELTS calibration of the algorithm allows for higher pressure (10-30 kbars) regimes, and is more appropriate for modeling melt compositions and equilibrium conditions for a source within the martian mantle. We use the pMELTS program to model how partial melting of the martian mantle could evolve magmas into the surface compositions derived from the GRS instrument, and how the mantle beneath Elysium has changed over time. We attribute changes to lithospheric loading by long term, episodic volcanism within the EVP throughout its history. 1. Vaucher, J. et al. The volcanic history of central Elysium Planitia: Implications for martian magmatism. Icarus 204, 418-442 (2009). 2. Susko, D. et al. A record of igneous evolution in Elysium, a major martian volcanic province. Scientific Reports 7, 43177 (2017). 3. El Maarry, M. R. et al. Gamma-ray constraints on the chemical composition of the martian surface in the Tharsis region: A signature of partial melting of the mantle? Journal of Volcanology and Geothermal Research 185, 116-122 (2009). 4. Ding, S. & Dasgupta, R. The fate of sulfide during decompression melting of peridotite - implications for sulfur inventory of the MORB-source depleted upper mantle. Earth and Planetary Science Letters 459, 183-195 (2017). 5. Sakaia, R., Nagaharaa, H., Ozawaa, K. & Tachibanab, S. Composition of the lunar magma ocean constrained by the conditions for the crust formation. Icarus 229, 45-56 (2014).

A Mid-Summer's Dust Devil

NASA Technical Reports Server (NTRS)

2001-01-01

One objective for the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) in the Extended Mission is to continue looking for changes and dynamic events taking place on the red planet. The feature shown here elicited gasps of excitement among the MOC Operations Staff when it was received in early April 2001.

The feature is a dust devil. Dust devils are spinning, columnar vortices of wind that move across the landscape, pick up dust, and look somewhat like miniature tornadoes. Dust devils are a common occurrence in dry and desert landscapes on Earth as well as Mars. When this dust devil was spied in Amazonis Planitia on April 10th, the MOC was looking straight down. Usually when the camera is looking down the dust devil will appear as a circular, fuzzy patch with a straight shadow indicating its columnar shape. In this case, however, the dust devil is somewhat curved and kinked--its shape is best seen in the shadow it casts to the right. A thin, light-toned track has been left by the dust devil as it moved eastward across the landscape. Usually, such tracks are darker than the surroundings, in this case the light tone might indicate that the dust being removed by the passing dust devil is darker than the surface underneath the thin veneer of dust.

Dust devils most typically form when the ground heats up during the day, warming the air immediately above the surface. As the warmed air nearest the surface begins to rise, it spins. The spinning column begins to move across the surface and picks up loose dust (if any is present). The dust makes the vortex visible and gives it the 'dust devil' or tornado-like appearance. This dust devil occurred at an optimal time for dust devils whether on Earth or Mars--around 2 p.m. local time in the middle of Northern Hemisphere Summer. North is up, sunlight illuminates the scene from the left (west), and 500 meters is about 547 yards. The shadow cast by the dust devil goes off the edge of the image, but the length shown here (about 1.5 km) indicates that the dust devil was a bit more than 1 km (0.62 mi) in height.

Geology of Southern Guinevere Planitia, Venus, based on analyses of Goldstone radar data

NASA Technical Reports Server (NTRS)

Arvidson, R. E.; Plaut, J. J.; Jurgens, R. F.; Saunders, R. S.; Slade, M. A.

1989-01-01

The ensemble of 41 backscatter images of Venus acquired by the S Band (12.6 cm) Goldstone radar system covers approx. 35 million km and includes the equatorial portion of Guinevere Planitia, Navka Planitia, Heng-O Chasma, and Tinatin Planitia, and parts of Devana Chasma and Phoebe Regio. The images and associated altimetry data combine relatively high spatial resolution (1 to 10 km) with small incidence angles (less than 10 deg) for regions not covered by either Venera Orbiter or Arecibo radar data. Systematic analyses of the Goldstone data show that: (1) Volcanic plains dominate, including groups of small volcanic constructs, radar bright flows on a NW-SE arm of Phoebe Regio and on Ushas Mons and circular volcano-tectonic depressions; (2) Some of the regions imaged by Goldstone have high radar cross sections, including the flows on Ushas Mons and the NW-SE arm of Phoebe Regio, and several other unnamed hills, ridged terrains, and plains areas; (3) A 1000 km diameter multiringed structure is observed and appears to have a morphology not observed in Venera data (The northern section corresponds to Heng-O Chasma); (4) A 150 km wide, 2 km deep, 1400 km long rift valley with upturned flanks is located on the western flank of Phoebe Regio and extends into Devana Chasma; (5) A number of structures can be discerned in the Goldstone data, mainly trending NW-SE and NE-SW, directions similar to those discerned in Pioneer-Venus topography throughout the equatorial region; and (6) The abundance of circular and impact features is similar to the plains global average defined from Venera and Arecibo data, implying that the terrain imaged by Goldstone has typical crater retention ages, measured in hundreds of millions of years. The rate of resurfacing is less than or equal to 4 km/Ga.

Geological Map of the Fredegonade (V-57) Quadrangle, Venus: Status Report

NASA Technical Reports Server (NTRS)

Ivanov, M. A.; Head, J. W.

2010-01-01

The Fredegonde quadrangle (V-57; 50-75degS, 60-120degE, Fig. 1) corresponds to the northeastern edge of Lada Terra and covers a broad area of the topographic province of midlands (0-2 km above MPR [1,2]). This province is most abundant on Venus and displays a wide variety of units and structures [3-11]. The sequence of events that formed the characteristic features of the midlands is crucially important in understanding of the timing and modes of evolution of this topographic province. Topographically, the Fredegonde quadrangle is within a transition zone between the elevated portion of Lada Terra to the west (Quetzalpetlatl-Boala Coronae rise, approx.3.5 km) and the lowland of Aino Planitia to the north and northeast (approx.-0.5 km). This transition is one of the key features of the V-57 quadrangle. In this respect the quadrangle resembles the region of V-4 quadrangle [12] that shows transition between the midlands and the lowlands of Atalanta Planitia. One of the main goals of our mapping within the V-57 quadrangle is comparison of this region with the other transitional topographic zones such as quadrangles V-4 and V-3 [13]. The most prominent features in the V-57 quadrangle are linear deformational zones of grooves and large coronae. The zones characterize the central and NW portions of the map area and represent broad (up to 100s of km wide) ridges that are 100s of m high. Morphologically and topographically, these zones are almost identical to the groove belt/corona complexes at the western edge of Atalanta Planitia [12]. Within the Fredegonde area, however, the zones are oriented at high angles to the general trend of elongated Aino Planitia, whereas within the V-4 quadrangle they are parallel to the edge of Atalanta Planitia. Relatively small (100s of km across, 100s of m deep) equidimensional basins occur between the corona-groove-chains in the area of V-57 quadrangle. These basins are similar to those that populate the area of the V-3 quadrangle [13]. Broad regional plains cover the surface of the basins in both regions. In contrast to Fredegonde, the area of the V-3 quadrangle displays a greater diversity of units and features [13]. Here we describe units that make up the surface within the V-57 quadrangle and present a summary of our geological map that shows the areal distribution of the major groups of units.

Student Evaluation of UTOPIA

ERIC Educational Resources Information Center

Pearson, M.; Carswell, D. J.

1978-01-01

Reports some reactions and opinions of the students to a course in nuclear and radiation chemistry using programmed instructional aids. Concludes that the findings were very favorable to the course. (GA)

Thermal analysis of fractures at Cerberus Fossae, Mars: Detection of air convection in the porous debris apron

NASA Astrophysics Data System (ADS)

Antoine, R.; Lopez, T.; Baratoux, D.; Rabinowicz, M.; Kurita, K.

2011-08-01

This study investigates the cause of high nighttime temperatures within Cerberus Fossae, a system of fractures affecting the Central Elysium Planitia. The inner parts (walls and floor) of the fractures are up to 40 K warmer than the surrounding plains. However, several temperature profiles exhibit a local temperature minima occurring in the central part of the fractures. We examined first the influence of cooling efficiency at night in the case of a strong reduction of the sky proportion induced by the fracture's geometry. However, the lack of correlation between temperature and sky proportion, calculated from extracted Mars Orbiter Laser Altimeter (MOLA) profiles argues against this hypothesis. Albedo variations were considered but appear to be limited within the fractures, and are generally not correlated with the temperatures. Variations of the thermal properties of bedrocks exposures, debris aprons and sand dunes inferred from high-resolution images do not either correlate with temperature variations within the fractures. As none of these factors taken alone, or combined, can satisfactorily explain the temperature variations within and near the fracture, we suggest that geothermal heat transported by air convection within the porous debris aprons may contribute to explain high temperatures at night and the local minima on the fracture floor. The conditions for the occurrence of the suggested phenomenon and the consequences on the surface temperature are numerically explored. A conservative geothermal gradient of 20 mW/m 2 was used in the simulations, this value being consistent with either inferred lithosphere elastic thicknesses below the shield volcanoes of the Tharsis dome or values predicted from numerical simulations of the thermal evolution of Mars. The model results indicate that temperature differences of 10-20 K between the central and upper parts of the fracture are explained in the case of high Darcy velocities which require high permeability values (5 × 10 -6 m 2). The presence of coarse material composing the debris aprons may explain why this key criteria was met in the context of Cerberus Fossae.

Blind tests of methods for InSight Mars mission: Open scientific challenge

NASA Astrophysics Data System (ADS)

Clinton, John; Ceylan, Savas; Giardini, Domenico; Khan, Amir; van Driel, Martin; Böse, Maren; Euchner, Fabian; Garcia, Raphael F.; Drilleau, Mélanie; Lognonné, Philippe; Panning, Mark; Banerdt, Bruce

2017-04-01

The Marsquake Service (MQS) will be the ground segment service within the InSight mission to Mars, which will deploy a single seismic station on Elysium Planitia in November 2018. The main tasks of the MQS are the identification and characterisation of seismicity, and managing the Martian seismic event catalogue. In advance of the mission, we have developed a series of single station event location methods that rely on a priori 1D and 3D structural models. In coordination with the Mars Structural Service, we expect to use iterative inversion techniques to revise these structural models and event locations. In order to seek methodological advancements and test our current approaches, we have designed a blind test case using Martian synthetics combined with realistic noise models for the Martian surface. We invite all scientific parties that are interested in single station approaches and in exploring the Martian time-series to participate and contribute to our blind test. We anticipate the test will can improve currently developed location and structural inversion techniques, and also allow us explore new single station techniques for moment tensor and magnitude determination. The waveforms for our test case are computed employing AxiSEM and Instaseis for a randomly selected 1D background model and event catalogue that is statistically consistent with our current expectation of Martian seismicity. Realistic seismic surface noise is superimposed to generate a continuous time-series spanning 6 months. The event catalog includes impacts as well as Martian quakes. The temporal distribution of the seismicity in the timeseries, as well as the true structural model, are not be known to any participating parties including MQS till the end of competition. We provide our internal tools such as event location codes, suite of background models, seismic phase travel times, in order to support researchers who are willing to use/improve our current methods. Following the deadline of our blind test in late 2017, we plan to combine all outcomes in an article with all participants as co-authors.

A numerical circulation model with topography for the Martian Southern Hemisphere

NASA Technical Reports Server (NTRS)

Mass, C.; Sagan, C.

1975-01-01

A quasi-geostrophic numerical model, including friction, radiation, and the observed planetary topography, is applied to the general circulation of the Martian atmosphere in the Southern Hemisphere at latitudes south of about 35 deg. Near equilibrium weather systems developed after about 5 model days. To avoid violating the quasi-geostrophic approximation, only 0.8 of the already smoothed relief was employed. Weather systems and velocity fields are strikingly tied to topography. A 2mb middle latitude jet stream is found of remarkably terrestrial aspect. Highest surface velocities, both horizontal and vertical, are predicted in western Hellas Planitia and eastern Argyre Planitia, which are observed to be preferred sites of origin of major Martian dust storms. Mean horizontal velocities and vertical velocities are found just above the surface velocity boundary layer.

The Erebus Montes Debris-Apron Population: Investigation of Amazonian Landscape Evolution

NASA Astrophysics Data System (ADS)

van Gasselt, S.; Orgel, C.; Schulz, J.

2014-04-01

Lobate debris aprons are considered to be indicators for the presence of ice and water reservoirs on Mars and are therefore sensitive to climate variability. The northern hemisphere of Mars is characterized by three major populations of debris aprons (see, e.g. [12]): (1) the Tempe Terra/Mareotis Fossae region [2, 5], (2) the Deuteronilus/Protonilus Mensae [1, 4, 8], and (3) the Phlegra Montes (PM) [3]. The broader PM area can subdivided inro a number of smaller populations dispersed across parts of Arcadia Planitia (see figure 1) of which the Erebus Montes located at 180-195oE, 25-41oN form a well-confined set of features. We here focus on age and erosional characteristics of the northern Erebus Montes (see inset in figure 1). Our study makes use of panchromatic image data obtained by the High Resolution Stereo Camera (HRSC) [9, 6] onboard Mars Express and the Context Camera (CTX) [7] onboard Mars Reconnaissance Orbiter. Image data analyses are supported by digital terrain-model data derived from HRSC based stereo imaging [10] and from Mars Orbiter Laser Altimeter (MOLA) [11]. We performed detailed geologic mapping at a scale of 1:10,000 and analysed age relationships and erosion rates based on a similar approach as outlined in [5] for the northern part of the Erebus Montes. The aim of this study is to compare feature characteristics to other populations in order to assess timing and the overarching control of landforms evolution in the Martian northern hemisphere. The EM compare geologically relatively well with the Phlegra Montes in terms of individual feature morphologies. The concentration based on cluster analysis (figure 1) shows an up to 10 times higher concentration of remnants per 25 km2 area peaking at 3.4×10-3 features for Erebus Montes. Debris aprons show well-defined age signals ranging from 15 Myr up to 145 Myr. Some units even show continuous degradation implying active denudation of the Noachian to Hesperian-aged remnant massifs. Based on the current status of investigations latitudinally dependent age trends cannot be observed which is likely to be related to the small extent of the northern region. Erosion rates determined at selected remnants are comparable to the Tempe Terra region with 0.1-0.3 mm·a-1 (100-300 B) [5], depending on the model that has been used for our calculations. An explanation for such high Amazonian rates could be that much of the apron material has not been accumulated through denudation processes but by atmospheric deposition and removal of material from high-relief areas.

ET versus Alien : Popular Attitudes to bringing back Biological Material from Space

NASA Astrophysics Data System (ADS)

Evans, D.

The general public tend to react to radical scientific innovation in extreme ways, seeing them alternatively as a passport to utopia or a ticket to hell. The possible discovery of alien life forms has generated both types of reaction, as a brief survey of Hollywood movies shows. In this fanciful world, alens are either the friendly beings of ET and Close Encounters, who show us a way to improve ourselves, or the frightening monsters of Alien and Independence Day, who are bent on our destruction. Yet most astrobiologists would agree that both types of scenario are extremely unlikely. If we do encounter other life forms, the scientific consensus is that such life is vastly more likely to be microbial than to be an advanced, intelligent multicellular species. The public focus on the improbable stories of Hollywood means that they are little prepared to engage in sensible dialogue about plans for sample return missions from Mars and other planets. Unless scientific organisations take steps to encourage a more realistic understanding of the kinds of life we are most likely to encounter in space, we risk seeing public debate on these matters degenerate into the same hysteria and idiocy as that which has surrounded the use of GM foods and stem cell research.

Kos, Dresden, Utopia... A journey through idealism past and present in public health.

PubMed

Mackenbach, Johan

2005-01-01

This essay reviews some of the sources of idealism in public health, on the basis of an intellectual journey to Kos (home to Hippocrates and his altruistic legacy), Dresden (where the Deutsches Hygiene Museum illustrates the historical connections between fascism and public health), and Utopia (exemplified by Etienne Cabet's Icarie, a fantasy of an ideal city which has nevertheless been partly realized). It is suggested that the large-scale altruism of public health has to be balanced with the value of individual autonomy, and that some degree of dreaming of a better and healthier world is indispensable for further progress in public health. The main conclusion is that the ethical foundations of public health are not always self-evident, and that critical reflection on these foundations was, is, and will always be necessary.

The rapid formation of Sputnik Planitia early in Pluto's history.

PubMed

Hamilton, Douglas P; Stern, S A; Moore, J M; Young, L A

2016-11-30

Pluto's Sputnik Planitia is a bright, roughly circular feature that resembles a polar ice cap. It is approximately 1,000 kilometres across and is centred on a latitude of 25 degrees north and a longitude of 175 degrees, almost directly opposite the side of Pluto that always faces Charon as a result of tidal locking. One explanation for its location includes the formation of a basin in a giant impact, with subsequent upwelling of a dense interior ocean. Once the basin was established, ice would naturally have accumulated there. Then, provided that the basin was a positive gravity anomaly (with or without the ocean), true polar wander could have moved the feature towards the Pluto-Charon tidal axis, on the far side of Pluto from Charon. Here we report modelling that shows that ice quickly accumulates on Pluto near latitudes of 30 degrees north and south, even in the absence of a basin, because, averaged over its orbital period, those are Pluto's coldest regions. Within a million years of Charon's formation, ice deposits on Pluto concentrate into a single cap centred near a latitude of 30 degrees, owing to the runaway albedo effect. This accumulation of ice causes a positive gravity signature that locks, as Pluto's rotation slows, to a longitude directly opposite Charon. Once locked, Charon raises a permanent tidal bulge on Pluto, which greatly enhances the gravity signature of the ice cap. Meanwhile, the weight of the ice in Sputnik Planitia causes the crust under it to slump, creating its own basin (as has happened on Earth in Greenland). Even if the feature is now a modest negative gravity anomaly, it remains locked in place because of the permanent tidal bulge raised by Charon. Any movement of the feature away from 30 degrees latitude is countered by the preferential recondensation of ices near the coldest extremities of the cap. Therefore, our modelling suggests that Sputnik Planitia formed shortly after Charon did and has been stable, albeit gradually losing volume, over the age of the Solar System.

The rapid formation of Sputnik Planitia early in Pluto's history

NASA Astrophysics Data System (ADS)

Hamilton, Douglas P.; Stern, S. A.; Moore, J. M.; Young, L. A.; Binzel, R. P.; Buie, M. W.; Buratti, B. J.; Cheng, A. F.; Ennico, K.; Grundy, W. M.; Linscott, I. R.; McKinnon, W. B.; Olkin, C. B.; Reitsema, H. J.; Reuter, D. C.; Schenk, P.; Showalter, M. R.; Spencer, J. R.; Tyler, G. L.; Weaver, H. A.

2016-12-01

Pluto's Sputnik Planitia is a bright, roughly circular feature that resembles a polar ice cap. It is approximately 1,000 kilometres across and is centred on a latitude of 25 degrees north and a longitude of 175 degrees, almost directly opposite the side of Pluto that always faces Charon as a result of tidal locking. One explanation for its location includes the formation of a basin in a giant impact, with subsequent upwelling of a dense interior ocean. Once the basin was established, ice would naturally have accumulated there. Then, provided that the basin was a positive gravity anomaly (with or without the ocean), true polar wander could have moved the feature towards the Pluto-Charon tidal axis, on the far side of Pluto from Charon. Here we report modelling that shows that ice quickly accumulates on Pluto near latitudes of 30 degrees north and south, even in the absence of a basin, because, averaged over its orbital period, those are Pluto's coldest regions. Within a million years of Charon's formation, ice deposits on Pluto concentrate into a single cap centred near a latitude of 30 degrees, owing to the runaway albedo effect. This accumulation of ice causes a positive gravity signature that locks, as Pluto's rotation slows, to a longitude directly opposite Charon. Once locked, Charon raises a permanent tidal bulge on Pluto, which greatly enhances the gravity signature of the ice cap. Meanwhile, the weight of the ice in Sputnik Planitia causes the crust under it to slump, creating its own basin (as has happened on Earth in Greenland). Even if the feature is now a modest negative gravity anomaly, it remains locked in place because of the permanent tidal bulge raised by Charon. Any movement of the feature away from 30 degrees latitude is countered by the preferential recondensation of ices near the coldest extremities of the cap. Therefore, our modelling suggests that Sputnik Planitia formed shortly after Charon did and has been stable, albeit gradually losing volume, over the age of the Solar System.

Mars Express Scientific Overview After One Martian Year in Orbit

NASA Astrophysics Data System (ADS)

Chicarro, A. F.

2005-12-01

The ESA Mars Express mission was successfully launched on 02 June 2003 from Baikonur, Kazakh-stan, onboard a Russian Soyuz rocket with a Fregat upper stage. The mission comprises an orbiter space-craft, which has been placed in a polar martian orbit, and the small Beagle-2 lander, due to land in Isidis Planitia but whose fate remains unknown. In addition to global studies of the surface, subsurface and at-mosphere of Mars, with an unprecedented spatial and spectral resolution, the unifying theme of the mis-sion is the search for water in its various states everywhere on the planet. Following the Mars Express spacecraft commissioning in January 2004, most experiments onboard be-gan their own calibration and testing phase already acquiring scientific data. This phase lasted until June 2004 when all the instruments started their routine operations. The MARSIS radar antennas, however, were deployed in May-June 2005, following comprehensive simulations of boom deployment and mitiga-tion of potential risks, to benefit from nightime conditions required for subsurface sounding before the pericentre natural drift in latitude, when illumination conditions become favourable to the other instru-ments. Initial science results are summarised below. The High-Resolution Stereo Colour Imager (HRSC) has shown breathtaking views of the planet, in particular of karstic regions near the Valles Marineris canyon (pointing to liquid water as the erosional agent responsible for modifying tectonic and impact features in the area) and of several large volcanoes (Olympus Mons caldera and glaciation features surrounding Hecates Tholus). The IR Mineralogical Mapping Spectrometer (OMEGA) has provided unprecedented maps of water ice and CO2 ice occurrence in the South pole, showing where the two ices mix and where they do not. The Planetary Fourier Spec-trometer (PFS) has confirmed the presence of methane for the first time, which would indicate current volcanic activity and/or biological processes. The UV and IR Atmospheric Spectrometer (SPICAM) has provided the first complete vertical profile of CO2 density and temperature, and has simultaneously meas-ured the distribution of water vapour and ozone. The Energetic Neutral Atoms Analyser (ASPERA) has identified the solar wind interaction with the upper atmosphere and has measured the properties of the planetary wind in the Mars tail. The Radio Science Experiment (MaRS) has studied for the first time the surface roughness by pointing the spacecraft high-gain antenna to the Martian surface, which reflects the signal before sending it to Earth. Also, the martian interior has been probed by studying the gravity anomalies affecting the orbit due to mass variations of the crust. Finally, preliminary results of the subsur-face sounding radar (MARSIS) indicate strong echoes coming from the surface but lack of echoes under the young smooth Northern plains, which may indicate the presence of thick and homogeneous plains deposits. Water is the unifying theme of the mission to be studied by all instruments using different techniques. Mars Express is already hinting at a quantum leap in our understanding of the planet's geological evolu-tion, to be complemented by the ground truth being provided by the American MER rovers. The nominal lifetime of the orbiter spacecraft is of one Martian year (687 days), potentially to be ex-tended by another Martian year to complete global coverage and observe all seasons twice. Mars Express is the first European mission to another planet.

Topography of Sputnik Planitia Basin on Pluto: What We Know and Don't Know

NASA Astrophysics Data System (ADS)

Schenk, P.; Beyer, R. A.; McKinnon, W. B.; Moore, J.; Spencer, J. R.; Stern, A.; Weaver, H. A., Jr.; Olkin, C.; Ennico Smith, K.

2017-12-01

Pluto's topography is complex and reflects a diversity of geologic processes throughout its history. The most dominant feature is the deep 1200-by-2000-km-wide topographic depression enclosing the Sputnik Planitia nitrogen-rich ice sheet. Centered in the encounter hemisphere this large basin is ideally suited for topographic analysis. Despite this, considerable effort is required to constrain the true depth of this giant feature due to the uncertainties in controlling MVIC line-scan images, our primary source for long-wavelength information. Here we will summarize the current state of knowledge of this feature, as processing continues. Current estimates are that the floor of the observed basin (i.e., the top of the ice sheet) is 2-2.5 km depressed below the mean elevation of the surface. There is a highly eroded annular raised arched-ridge surrounding most of the basin that rises up to 1 km above mean surface. The surface of most of the ice sheet appears to be remarkably level within the limits of measurement ( 125 m). Comparison to other similar-sized depressions on Mars and the Moon support the interpretation that this is a large ancient impact structure. The outer 20-40- km of the ice sheet can be either depressed or raised several hundred meters, with the depressed moat forming north of 30° latitude or so, the raised portions forming south of this and corresponding to areas where glacier-like flow of material from the elevated rim regions meets the ice sheet. This suggests that the equatorial areas are areas of net accumulation of ice and the areas to the north are net deflation or lateral flow. The ice sheet is also characterized by polygonal and ovoid `cells' diagnostic of convection. These have shading patterns consistent with cell centers being raised in elevation. Preliminary shape-from-shading measurements suggest elevations of 100-200 m, consistent with weak stereo observations, though much more work is required on all these topics. Interpolation of d/D statistics for smaller craters implies a minimum depth of the original basin floor of 10 km below the rim (assuming that low angle or low-impact-velocity effects do not produce an anomalous basin profile). Pending updates, this would imply a possible maximum thickness of the observed ice sheet of 6 km.

Tidal-Rotational Dynamics of Solar System Worlds, from the Moon to Pluto

NASA Astrophysics Data System (ADS)

Keane, James Tuttle

The spins of planetary bodies are not stagnant; they evolve in response to both external and internal forces. One way a planet's spin can change is through true polar wander. True polar wander is the reorientation of a planetary body with respect to its angular momentum vector, and occurs when mass is redistributed within the body, changing its principal axes of inertia. True polar wander can literally reshape a world, and has important implications for a variety of processes--from the long-term stability of polar volatiles in the permanently shadowed regions of airless worlds like the Moon and Mercury, to the global tectonic patterns of icy worlds like Pluto. In this dissertation, we investigate three specific instances of planetary true polar wander, and their associated consequences. In Chapter 2 we investigate the classic problem of the Moon's dynamical figure. By considering the effects of a fossil figure supported by an elastic lithosphere, and the contribution of impact basins to the figure, we find that the lunar figure is consistent with the Moon's lithosphere freezing in when the Moon was much closer to the Earth, on a low eccentricity synchronous orbit. The South Pole-Aitken impact basin is the single largest perturbation to the Moon's figure and resulted in tens of degrees of true polar wander after its formation. In Chapter 3 we continue our analyses of the lunar figure in light of the discovery of a lunar "volatile" paleopole, preserved in the distribution of hydrogen near the Moon's poles. We find that the formation and evolution of the Procellarum KREEP Terrain significantly altered the Moon's orientation, implying that some fraction of the Moon's polar volatiles are ancient--predating the geologic activity within the Procellarum region. In Chapter 4 we investigate how the formation of the giant, basin-filling glacier, Sputnik Planitia reoriented Pluto. This reorientation is recorded in both the present- day location of Sputnik Planitia (near the Pluto-Charon tidal axis), and the tectonic record of Pluto. This reorientation likely reflects a coupling between Pluto's volatile cycles and rotational dynamics, and may be active on other worlds with comparably large, mobile volatile reservoirs. Finally, in Chapter 5 we consider the broader context of these studies, and touch on future investigations of true polar wander on Mercury, Venus, Mars, Vesta, Ceres, and other worlds in our solar system.

Crater

NASA Image and Video Library

2015-09-03

This relatively young crater is located on the northern plains of Arcadia Planitia. Orbit Number: 60388 Latitude: 61.6777 Longitude: 228.91 Instrument: VIS Captured: 2015-07-26 03:01 http://photojournal.jpl.nasa.gov/catalog/PIA19766

Observed Changes at Viking Lander 1

NASA Technical Reports Server (NTRS)

Moore, H. J.

1985-01-01

A local dust storm raged in Chryse Planitia, Mars, in June 1981. The changes wrought in the vicinity of the lander (Mutch Memorial Station) by this storm sometime near Sol 1742 were partly described previously. Here, changes related to the storm are itemized, evidence for wind directions during the peak of the storm are cited, and two observations unrelated to the storm are noted. The observations suggest that the eroding winds of the Sol 1742 storm were more easterly (N. 35 deg to 90 deg E.) than those (N. 5 deg to 11 deg E.) that formed the large wind tails; and fragments in erosional residues are 0.7 cm and larger, but smaller ones may be present. Some fragments 0.4 to 0.5 cm and smaller were somehow removed, at least locally; wind speeds of the 1742 local storm were probably greater than those of a previous local dust storm (25 to 30 m/s) that occurred during the same season on Sol 423 because the earlier storm did not alter the surface; the major, if not entire, amount of erosion by the storm occurred between Sols 1728 and 1757; and erosion chiefly occurred where the surface configuration and material properties were altered by the lander and its sampler.

The effect of giant impactors on the magnetic field energy of an early Martian dynamo.

NASA Astrophysics Data System (ADS)

Drummond, McGregor; Thieulot, Cedric; Monteux, Julien

2016-04-01

Through the cratering record embedded on its surface, Mars is one of the key planets required for investigating the formation and impact frequency in the early history of our Solar System. This record also holds clues to the events that may have caused the observed hemispheric dichotomy and cessation of the magnetic field that was present within the first 500 Myr of the planets' formation. We investigate the influence of giant impacts on the early Martian dynamo using the numerical dynamo modelling code PARODY-JA [1]. We hypothesize that the input heat from a giant impact will decrease the total heat flux at the CMB through mantle heating which leads to a decrease in the Rayleigh number of the core. As boundary conditions for the heat flux anomaly size, we use numerical results of a 750 km diameter impactor from the Monteux and Arkani-Hamed, 2014 [2] study which investigated impact heating and core merging of giant impacts in early Mars. We also determine the decrease in Rayleigh number from the change in total heat flux at the CMB using these results, where the decrease after impact is due to shock heating at the CMB. We calculate the time-averaged total magnetic field energy for an initial homogeneous heat flux model using a range of Rayleigh numbers (5 x 103 - 1 x 10^5). The Rayleigh number is then decreased for three new models - homogeneous, north pole impact and equatorial impact - and the time-averaged energy again determined. We find that the energy decreases more in our impact models, compared with the homogeneous, along with a variation in energy between the north pole and equatorial impact models. We conclude that giant impacts in Mars' early history would have decreased the total magnetic energy of the field and the decrease in energy is also dependent on the location of the impact. The magnetic field could have been disrupted beyond recovery from a planetesimal-sized collision; such as the suggested Borealis basin forming impact, or through the cumulative effect of multiple large impactors; such as Utopia, Hellas and Isidis basin forming impacts. [1] Aubert, J., Aurnou, J. & Wicht, J., 2008. The magnetic structure of convection-driven numerical dynamos. Geophys. J. Int., 172, 945--956. [2] Monteux, J., Arkani-Hamed, J., 2014. Consequences of giant impacts in early Mars: core merging and Martian dynamo evolution. J. Geophys. Res. (Planets) 119, 480--505.

Observed glacier and volatile distribution on Pluto from atmosphere-topography processes.

PubMed

Bertrand, Tanguy; Forget, François

2016-12-01

Pluto has a variety of surface frosts and landforms as well as a complex atmosphere. There is ongoing geological activity related to the massive Sputnik Planitia glacier, mostly made of nitrogen (N 2 ) ice mixed with solid carbon monoxide and methane, covering the 4-kilometre-deep, 1,000-kilometre-wide basin of Sputnik Planitia near the anti-Charon point. The glacier has been suggested to arise from a source region connected to the deep interior, or from a sink collecting the volatiles released planetwide. Thin deposits of N 2 frost, however, were also detected at mid-northern latitudes and methane ice was observed to cover most of Pluto except for the darker, frost-free equatorial regions. Here we report numerical simulations of the evolution of N 2 , methane and carbon monoxide on Pluto over thousands of years. The model predicts N 2 ice accumulation in the deepest low-latitude basin and the threefold increase in atmospheric pressure that has been observed to occur since 1988. This points to atmospheric-topographic processes as the origin of Sputnik Planitia's N 2 glacier. The same simulations also reproduce the observed quantities of volatiles in the atmosphere and show frosts of methane, and sometimes N 2 , that seasonally cover the mid- and high latitudes, explaining the bright northern polar cap reported in the 1990s and the observed ice distribution in 2015. The model also predicts that most of these seasonal frosts should disappear in the next decade.

Martian Rootless Cones as Indicators of Recent Deposits of Shallow Equatorial Ground Ice

NASA Astrophysics Data System (ADS)

Lanagan, P. D.; McEwen, A. S.; Keszthelyi, L. P.; Thordarson, T.

2001-05-01

Small, cratered cones have been identified in high-resolution Mars Orbiter Camera images of the Cerberus Plains and Amazonis Planitia, Mars [1].These cones occur in small clusters independent of obvious fissures, are superimposed on fresh lava flows, and do not appear to issue lavas themselves. Observed cones have basal diameters <250m and large summit craters. The structures are similar in both morphology and dimensions to the larger of Icelandic rootless cones,or pseudocraters [2], which form due to phreatomagmatic explosions caused by mechanical mixtures of tube-fed lavas with near-surface water-saturated substrates[3]. If the martian cones form in a similar manner as terrestrial rootless cones,then they may provide constraints on the spatial and temporal distribution of martian ground ice. Lavas associated with the western Amazonis cone fields(24N, 171W) show well-preserved surface morphologies and few superimposed impact craters. Impact crater statistics indicate that these lavas and superimposed cones may have been emplaced less than 10 Ma, indicating near-surface ice must have been present at the time. The presence of young rootless cones helps constrain the origins of ground ice. Relic ground ice is unlikely to be a volatile source for rootless eruptions as regolith in equatorial regions is likely to be desiccated to a depth of 200-m [4]. Vapor exchange between the regolith and atmosphere due to obliquity variations [5] may input enough water into the subsurface to reproduce martian cones of observed diameters calculated by explosion models[6]. However, surficial waters released in outflow events may be required to recharge requisite quantities of ground ice. Most proposed rootless cone fields appear in or close to fluvial features of the Cerberus Plains and Marte Valles[7]. Nested summit craters of some cones indicate a multi-stage constructional process, which would require recharge of aquifers beneath the erupting cones. Such a process would require the substrate to be permeable and contain enough ground ice to allow water to flow to the explosion point. [1]Lanagan, P. D. et al.(2001)Geophys Res Let, submitted. [2]Thorarinsson, S.(1953)Bull Vol, 14, 3-44. [3]Thordarson, T.(2000)Volcano-Ice Interactions on Earth and Mars, 36. [4]Clifford, S. M., and Hillel, D.(1983)J Geophys Res, 88, 2456-2474. [5]Mellon, M. T., and B. M. Jakosky.(1995)J Geophys Res, 100, 11781-11799. [6]Fagents, S. A. and R. Greeley.(2000)Volcano-Ice Interactions on Earth and Mars, 13. [7]Burr, D. M. et al.(2001)Geophys Res Abs.

Soft robot design methodology for `push-button' manufacturing

NASA Astrophysics Data System (ADS)

Paik, Jamie

2018-06-01

`Push-button' or fully automated manufacturing would enable the production of robots with zero intervention from human hands. Realizing this utopia requires a fundamental shift from a sequential (design-materials-manufacturing) to a concurrent design methodology.

Scandinavia: A Racial Utopia?

ERIC Educational Resources Information Center

Weisbord, Robert G.

1972-01-01

Isolated personal observations have shaped the racial image of the Nordic countries--that Scandinavia is a racial paradise; this image is, however, simplistic, superficial, and one-dimensional. There is no gainsaying that prejudice against certain ethnic groups exists in Scandinavia. (Author)

Discriminating utopian from dystopian literature: Why is walden two considered a dystopia?

PubMed Central

Newman, Bobby

1993-01-01

Skinner thought of Walden Two as a utopia, but many literary critics consider it a dystopia. The present paper examines works by several authors of utopian literature in an effort to determine what elements lead critics to classify works as “dystopian.” Common elements seem to include (a) suspicion of scientific social planning, (b) the unhappiness of the characters portrayed, (c) suspicion of sources of control of behavior outside the individual, (d) violation of a presumed inherent need to struggle, and (e) suspicion of behavioral methods of governance. The elements Walden Two shares with other utopias and dystopias are examined, and the conclusion is offered that Walden Two could not be considered a dystopia for any of the traditional reasons. Instead, the negative view of Walden Two seems to be an outgrowth of literary devices and general negative reactions to behavioral determinism. PMID:22478144

Mass Wasting

NASA Image and Video Library

2011-12-06

Mass Wasting is the term given to the process of change on a surface due to gravity things moving downhill due to the force of gravity. Dark streaks mark the slopes of craters and hills in this region of Amazonis Planitia.

Geologic Mapping of V-19

NASA Technical Reports Server (NTRS)

Martin, P.; Stofan, E. R.; Guest, J. E.

2009-01-01

A geologic map of the Sedna Planitia (V-19) quadrangle is being completed at the 1:5,000,000 scale as part of the NASA Planetary Geologic Mapping Program, and will be submitted for review by September 2009.

Rehabilitation with Cystic Fibrosis: From Utopia to Reality.

ERIC Educational Resources Information Center

Goldberg, Richard T.; And Others

1980-01-01

The paper dispels some of the myths regarding cystic fibrosis (a genetic metabolism disorder), provides information on the latest developments in rehabilitation, summarizes research in the field, and projects future needs of the patient with cystic fibrosis. (SBH)

Geological Mapping of the North Polar Region of Venus (V-1 Snegurochka Planitia): Significant Problems and Comparisons to the Earth's Archean

NASA Technical Reports Server (NTRS)

Head, James W.; Hurwitz, D. M.; Ivanov, M. A.; Basilevsky, A. T.; Kumar, P. Senthil

2008-01-01

The geological features, structures, thermal conditions, interpreted processes, and outstanding questions related to both the Earth's Archean and Venus share many similarities and we are using a problem-oriented approach to Venus mapping, guided by perspectives from the Archean record of the Earth, to gain new insight into both. The Earth's preserved and well-documented Archean record provides important insight into high heat-flux tectonic and magmatic environments and structures and Venus reveals the current configuration and recent geological record of analogous high-temperature environments unmodified by subsequent several billion years of segmentation and overprinting, as on Earth. We have problems on which progress might be made through comparison. Here we present the major goals of the geological mapping of the V-1 Snegurochka Planitia Quadrangle, and themes that could provide important insights into both planets:

Geologic Map of the Meskhent Tessera Quadrangle (V-3), Venus: Evidence for Early Formation and Preservation of Regional Topography

NASA Technical Reports Server (NTRS)

Ivanov, M. A.; Head, James W.

2008-01-01

The area of the Meskhent Tessera quadrangle (V-3, 50-75degN, 60-120degE, Fig. 1) corresponds to a transition zone from the uplands of Ishtar Terra to the west to the lowlands of Atalanta Planitia to the east. The topographic configuration, gravity signature, and presence of large tesserae in Ishtar Terra are consistent with extensive areas of thickened crust and tectonically stabilized lithosphere representing ancient and now extinct regimes of mantle convection. The gravity and topographic characteristics of Atalanta Planitia have been cited as evidence for large-scale mantle downwelling. Thus, the region of Meskhent Tessera quadrangle represents an important sample for the study of the regional history of long-wavelength topography (highlands, midlands, and lowlands), interaction between the downwelling and areas of thickened crust/lithosphere, formation of associated tectonic features, and emplacement of volcanic plains.

Basin-forming impacts on Mars and the coupled thermal evolution of the interior

NASA Astrophysics Data System (ADS)

Arkani-Hamed, J.; Roberts, J. H.

2015-12-01

The youngest of the Noachian giant impact basins on Mars, are either weakly magnetized or completely demagnetized, indicating that a global magnetic field was not present and that a core dynamo was not operating at the time those basins formed. Shock heating from this sequence of basin-forming impacts modified the pattern of mantle convection. The heating produced by the eight largest impacts (Acidalia, Amazonis, Ares, Chryse, Daedalia, Hellas, Scopolus, and Utopia) penetrates below the core-mantle boundary (CMB). Here, we extend previous workon coupled thermal evolution into 3D, in order to accurately model the spatial relationship between impact basins. At the time of each impact we introduce a temperature perturbation resulting from shock heating into the core and mantle. Stratification of the core occurs very quickly compared to mantle dynamics, and we horizontally average the temperature in the core.We model mantle convection using the 3D finite element code CitcomS, and the thermal evolution of the core using a 1D parameterization.Each impact alters the pattern of mantle dynamics and a significant amount of impact melt is produced in the near surface. However, only the outermost part of the core is affected; the inner core temperature is still adiabatic. Immediately following the impact, the inner core may remain convective. The top of the core will cool by conduction into the deeper core faster than across the CMB, deepening the zone of stable stratification. Further core cooling results in formation of a convecting zone at the top of the core that propagates downwards as the thermal gradient becomes adiabatic at greater depths. Our goal is to obtain a better estimate of the time scale for restoration of post-impact core dynamo activity. Because the disappearance of the magnetic field exposes the early atmosphere to solar wind activity, constraining the history of the dynamo is critical for understanding climate evolution and habitability of the surface.

MRO Context Camera (CTX) Investigation Primary Mission Results

NASA Astrophysics Data System (ADS)

Edgett, K. S.; Malin, M. C.; Science; Operations Teams, M.

2008-12-01

The Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) acquires panchromatic images of Mars at ~6 m/pixel; the majority cover areas 30 km wide by 43 to 313 km long. As of 31 August 2008, 36% of Mars was imaged at 6 m/pixel and 10.8% was covered more than once. Areas imaged multiple times include stereopairs and locations covered repeatedly to monitor dust-raising events, seasonal frost patterns, or landforms and albedo features known or anticipated to change. CTX provides context for data acquired by other MRO science instruments, as well. Using our knowledge of imaging performance as a function of seasonal atmospheric, frost, and insolation conditions from the 4 Mars-year Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) investigation, we undertook several time-dependent campaigns to create 6 m/pixel mosaics of regions such as Hellas Planitia, the south polar residual cap (covered in spring and in summer), and the north polar region. In addition, we obtained 6 m/pixel mosaics of the Valles Marineris, Sinus Meridiani, Marte Valles, Athabasca Valles, portions of the northern plains, fretted terrain and chaotic terrain, large volcanoes, yardang-forming materials in Amazonis and Aeolis, the small volcanoes and platy flows south of Cerberus, and many other regions. We monitored thousands of mid-latitude gullies, and we used our MOC experience to target dust-raising events that repeat every year at the same locations. Retreat of cliffs formed in layers of CO2 ice in the south polar cap was observed for the 5th southern summer since 1999. Dozens of new impact craters and crater clusters were observed; all formed since 1999 and some formed during the MRO Primary Mission. We routinely re-targeted the new impact sites to see how they change and alert other MRO instrument teams so they could observe them. CTX images of the cratered highlands emphasize the view that the upper crust of Mars is layered with interbedded filled and buried valleys, fluvial channels, and impact craters ranging in diameter from meters to hundreds of kilometers. CTX observations reiterate a critical MOC result regarding small, sub-kilometer diameter craters: the substrates most resistant to erosion retain the most small craters (and the boulders produced by the impacts). CTX images provide many examples in which a younger, harder substrate (e.g., a lava flow) is more heavily cratered (with < 1 km diameter craters) than subjacent, older rock units. One example occurs in the form of lava flows located immediately west of Meridiani Planum; similar flows underlie the hematite-bearing, plains- forming rock in nearby Miyamoto Crater. Northern Meridiani also exhibits exhumed, low-order streams (of the scale of hillslope rills and creeks); these were filled, buried, lithified, and later returned to the surface by erosion-some of them in inverted form. Terrain immediately west of Juventae Chasma exhibits similar inverted streams and rills that were first documented by MOC and provide key evidence for rainfall and hillslope runoff. CTX data show that there are many hundreds of inverted fluvial channels, of a variety of sizes, all over the planet, especially in Arabia Terra, Solis Planum, and Thaumasia. We also used CTX to map a small, unnamed outflow channel system west of Bond Crater, and we have been documenting all of the small Martian volcanoes, typically < 30 km across, including those occurring in the Labyrinthus Noctis. CTX data are widely available, as they are archived with the NASA Planetary Data System on a rolling basis every 6 months.

Geologic Map of the Aino Planitia (V46) Quadrangle, Venus 1:5,000,000

USGS Publications Warehouse

Stofan, Ellen R.; Guest, John E.

2003-01-01

The Aino Planitia quadrangle (V-46) extends from 25?-50? S. latitude, 60?-90? E. longitude. The quadrangle was mapped at 1:5,000,000 scale as part of the NASA Planetary Geologic Mapping Program. Aino Planitia is a lowland region in the southern hemisphere of Venus and is southwest of Thetis Regio in western Aphrodite Terra. It is dominated by low-lying plains units that are characterized by northeast-trending wrinkle ridges and numerous small volcanic edifices, including shields, domes, and cones. The quadrangle contains a major volcano, Kunapipi Mons, and portions of Juno Chasma. A northern extension of the Lada Terra highland is in the southwestern portion of the map. Eight coronae are mapped in the quadrangle, the largest of which is the 500-km-diameter Copia Corona. The region is dominated by plains that are interpreted to be of volcanic origin. Most of the plains units are composites of flow units of differing ages. The overall topography of V-46 consists of low-lying plains slightly below Mean Planetary Radius (MPR, 6051.84 km). The summit of Kunapipi Mons is the highest point in the quadrangle, at about 2.2 km above MPR; the lowest points in rifts and troughs are at about 1.7 km below MPR. The regions that are the roughest at Magellan radar wavelengths in the quadrangle occur along the rim of Copia Corona, with most regions being relatively smooth (roughness comparable to the average Venus surface. Emissivity values in the quadrangle vary from 0.82-0.90.

Composition and Mineralogy of Low Albedo Northern Circumpolar Deposits on Mars Using MGS/TES Data

NASA Astrophysics Data System (ADS)

Bell, J. F.; Horgan, B.; Noe Dobrea, E. Z.

2009-12-01

The northern high latitude non-ice geology of Mars is dominated by large, low-albedo sand dunes and sand sheet deposits. These materials have experienced a complex geologic history, including evidence preserved in the morphology for aeolian deposition, transport, and erosion (e.g., Tanaka et al., Icarus, 196, 318, 2008), and evidence preserved in the mineralogy for aqueous alteration processes (e.g., Langevin et al., Science, 307, 1584, 2005). These low-albedo materials span the circumpolar plains of Vastitas Borealis north of about 75 deg. latitude, and extend down to about 30 deg. north in the Acidalia Planitia region (from about 15 to 45 deg. west) where they are the type locality for the Mars Global Surveyor Thermal Emission Spectrometer (MGS/TES) "Surface Type 2" global compositional endmember. We are assessing both the morphology and primary (mafic) and secondary mineralogy of north polar sand deposits using high spatial and spectral resolution data sets, working to test hypotheses for the formation and evolution of these materials throughout Martian history. Here we report on our initial mineralogic analyses of TES mid-IR spectra of these low albedo materials. Because of the relatively low surface temperatures at high northern latitudes on Mars, assembling a high-quality TES data set that covers a significant fraction of representative terrains is a challenge. Ultimately we were able to identify and assemble a data subset of more than 5000 TES emissivity spectra having temperatures above 250K and covering surface regions with bolometric albedo below 0.15 during times of relatively clear atmospheric conditions. These spectra cover only a few percent of the north polar low albedo deposits, but they provide representative sampling of many terrains. We are performing atmospheric corrections and deriving estimated mineral abundances for these spectra using an iterative linear matrix inversion spectral unmixing method (Noe Dobrea et al., JGR, 111, 2006) and laboratory-derived mineral endmembers from the publicly-available TES library. This method allows us to compute best-fit abundances for all possible endmember combinations within a user-defined library subset, and to estimate average abundances for each modeled mineral. Minerals not detected above a minimum detection threshold are discarded, which then allows us to converge on models with the most statistically accurate representation of the likely mineral assemblage. The best-fit models of our average polar sand deposit spectra (using 68 spectrally-unique endmembers chosen to represent a range of potential primary and secondary mineralogies relevant to Mars) included "expected" mafic minerals (olivine, pyroxene, feldspar) plus a silica-bearing amorphous phase. The best models also included minor amounts of other phases, however, like Mg-, Al-, and Fe-bearing sulfates and iron oxides. Our TES mid-IR results enhance and augment previous interpretations (Horgan et al., JGR, 114, 2009) of the composition and mineralogy of these regions from Mars Express/OMEGA near-IR imaging spectroscopic observations, allowing us to explore the processes and relationships between primary minerals and previously-identified secondary alteration products in the region like polyhydrated sulfates.

Utopias past and future

NASA Astrophysics Data System (ADS)

Tyler, David J.; Blain, Barry

2016-05-01

In reply to Robert P Crease's article “Diversifying utopia” (March p29, http://ow.ly/104lZw), which discussed the near-absence of women in the novel New Atlantis, which was written in the 17th century by the natural philosopher Francis Bacon.

MOLA Topography of Impact Basins in the Northern Hemisphere of Mars

NASA Technical Reports Server (NTRS)

Frey, Herbert; Sakimoto, S. E. H.; Roark, J. H.

1998-01-01

Coverage of the northern hemisphere of Mars by the Mars Orbiter Laser Altimeter (MOLA) during the aerobraking hiatus and the two Science Phasing Operation periods provides improved definition and characterization of large impact basins. Gridded MOLA data show the Utopia Basin has a pronounced bowl-like structure, as opposed to the interior rises suggested by the earlier USGS DEM. The elevation structure is concentric about the basin center as mapped by McGill. In particular, the proposed inner ring closely follows the -4 km contour over much of the southern, western and northwestern sides. Higher topography along portions of the dichotomy boundary aligns with the basin's outer ring. High topography in the polar region also occurs where the outer ring should lie, raising the possibility that perhaps some of the polar topography is due to basin structure as well as ice. Two MOLA passes near Phison Rupes provide evidence for a large "stealth" hole where Viking imagery show little evidence of any major structure. The 2 km deep, 600 km wide depression at 31OW, 3ON is as large as the Cassini impact basin 1000 km to the SW. While Cassini is easily recognized in image data, the "MOLA Hole" is not. If this depression is a deeply eroded and buried impact basin (as perhaps suggested by a decrease in the crater density and somewhat smoother terrain than in adjacent areas), it is not clear why it has managed to maintain its great depth. In Tempe at the dichotomy boundary a 300 km wide impact basin is revealed by pronounced bowl-like topography centered at 87W, 47N, even though only about 1/3 of the basin rim structure is obvious. The basin lies on a sloping boundary zone, with the more buried N rim up to 2 km below the rugged S rim. A similar N-S asymmetry in basin ring structure occurs for the much larger Isidis Basin, where the S rim rises 6 km but the subdued N rim rises barely 2 km above the floor. There is essentially no topographic expression of the main ring in the NE quadrant of Isidis where, if it exists, it lies below Hesperian-age plains.

Sublimation pit distribution indicates convection cell surface velocities of ∼10 cm per year in Sputnik Planitia, Pluto

NASA Astrophysics Data System (ADS)

Buhler, Peter B.; Ingersoll, Andrew P.

2018-01-01

The ∼106 km2 Sputnik Planitia, Pluto is the upper surface of a vast basin of nitrogen ice. Cellular landforms in Sputnik Planitia with areas in the range of a few × 102-103 km2 are likely the surface manifestation of convective overturn in the nitrogen ice. The cells have sublimation pits on them, with smaller pits near their centers and larger pits near their edges. We map pits on seven cells and find that the pit radii increase by between 2.1 ± 0.4 × 10-3 and 5.9 ± 0.8 × 10-3 m m-1 away from the cell center, depending on the cell. This is a lower bound on the size increase because of the finite resolution of the data. Accounting for resolution yields upper bounds on the size vs. distance distribution of between 4.2 ± 0.2 × 10-3 and 23.4 ± 1.5 × 10-3 m m-1. We then use an analytic model to calculate that pit radii grow via sublimation at a rate of 3.6-0.6+2.1 ×10-4 m yr-1, which allows us to convert the pit size vs. distance distribution into a pit age vs. distance distribution. This yields surface velocities between 1.5-0.2+1.0 and 6.2-1.4+3.4 cm yr-1 for the slowest cell and surface velocities between 8.1-1.0+5.5 and 17.9-5.1+8.9 cm yr-1 for the fastest cell. These convection rates imply that the surface ages at the edge of cells reach ∼4.2-8.9 × 105 yr. The rates are comparable to rates of ∼6 cm yr-1 that were previously obtained from modeling of the convective overturn in Sputnik Planitia (McKinnon et al., 2016). Finally, we investigate the surface rheology of the convection cells and estimate that the minimum ice viscosity necessary to support the geometry of the observed pits is of order 1016-1017 Pa s, based on the argument that pits would relax away before growing to their observed radii of several hundred meters if the viscosity were lower than this value.

Martian Highlands at Night in Infrared

NASA Technical Reports Server (NTRS)

2002-01-01

This nighttime temperature image from the camera system on NASA's Mars Odyssey spacecraft shows the ancient, heavily cratered surface of the highlands between Isidis and Elysium Planitia. The image is entered near 9 degrees north latitude, 109 degrees east longitude, and covers an area approximately 32 kilometers (20 miles) wide by 120 kilometers (75 miles) long. The bright 'splashes' extending outward from the three large craters are the remnants of the rocky material thrown out when the impact occurred. The nighttime temperature differences are due primarily to differences in the abundance of rocky materials that retain their heat at night and stay relatively warm. Fine grained dust and sand cool off more rapidly at night. The circular rims of the craters in this region are warm at night, showing that rocks are still present on the steep walls inside the craters. The 'splash' ejecta patterns are also warmer than their surroundings, and are covered by material that was blasted out when the craters formed. The temperatures in this scene vary from approximately -105 degrees Celsius (-157 degrees Fahrenheit)(darkest) to -75 degrees Celsius (-103 degrees Fahrenheit) (lightest). This image was acquired using the instrument's infrared Band 9, centered at 12.6 micrometers. North is toward the left in this image.

The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the 2001 Mars Odyssey mission for NASA's Office of Space Science in Washington, D.C. Investigators at Arizona State University in Tempe, the University of Arizona in Tucson and NASA's Johnson Space Center, Houston, operate the science instruments. Additional science partners are located at the Russian Aviation and Space Agency and at Los Alamos National Laboratories, New Mexico. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL.

Regional Stratigraphy from Stereo Imaging near the Hypanis Fan Deposit: Marking the Extent of the Largest Delta on Mars?

NASA Astrophysics Data System (ADS)

Adler, J.; Harrison, T. N.; Bell, J. F., III; Mayer, D. P.

2017-12-01

The layered fan-shaped sedimentary deposit at the terminus of Hypanis Valles has been classified by some as an ancient delta marking the presence of a sea in Chryse Planitia, Mars. The deposit's age is estimated to be 3.6 Ga based on crater counts in the upstream catchment. We further our research on the Hypanis deposit and its relative age by analyzing digital terrain models and high-resolution orbital images of two key study areas: Lederberg crater rim and the distal island deposits. We constructed a 2 m/pix digital terrain model from our requested HiRISE stereo images (0.5 m/pix) of the Lederberg rim northwest of Hypanis, as well as a 24 m/pix digital terrain model from CTX stereo images (6 m/pix) of the island structures northeast of Hypanis. Both terrain models were controlled to MOLA shot data. We added these elevation models to a regional elevation mosaic in order to assess stratigraphy. We found that the Lederberg crater rim has polygonally fractured units, consistent with those in the plains near Hypanis, as well as an example of a distinct mildly sinuous ridge with smooth cones along its profile. We hypothesize that the formation of rounded cones in this region of Xanthe Terra near Hypanis is related to the presence of wrinkle ridges and degraded crater rims. Furthermore, we investigate whether these cones are the youngest geologic formations in the region, postdating the aqueous periods in which the delta and hydrovolcanic cones were formed. We also analyzed the elevation profiles of potential deltaic distal island deposits, and found that some islands are likely part of the main lobe of Hypanis, while others more closely match the chaos units to the east. From our analysis, it is unlikely that the large northern island was once part of the Hypanis deposit. Rather, a larger laterally continuous unit likely once draped the region post-Hypanis formation and has subsequently been eroded.

Styles of Phreatomagmatic Activity Adjacent to Volcanic Constructs on Mars

NASA Astrophysics Data System (ADS)

Wilson, L.; Mouginis-Mark, P.

2001-05-01

Early in the analysis of Viking Orbiter data, it was recognized that there were numerous sites on Mars where igneous intrusions may have interacted with ice near the surface. Hrad Vallis (34N, 142E) in Western Elysium Planitia, and Olympica Fossae (25N, 245E) to the southwest of Ceraunius Fossae, were two such candidate areas. New images from the Mars Orbiter Camera show striking differences between these two sites, revealing a wide diversity of depositional and erosional features. We are therefore exploring several potential terrestrial analogs to better constrain models of heat transfer from the igneous intrusion, the style of "eruption" of the water/sediment mixtures, and the hydrologic conditions in the substrate at the time of emplacement. We have found layering at the source of Hrad Vallis, and several nearby impact craters 270 - 530 m diameter that are almost totally mantled, consistent with the deposition of 20 - 30 m of sediment around the source graben. Prominent sub-radial ridges occur within this 8,400 km2 deposit; close to the source, these ridges have a spacing of 100 - 120 m but grade to smaller ridges 60 m apart within 2 km of the source. No "de-watering" features are visible on this unit. In contrast, Olympica Fossae displays no depositional features near the source graben. We interpret these morphologic differences to be due to a higher sediment load of the fluid that reached the surface at Hrad Vallis compared with Olympica Fossae. At neither site are there signs of "weeping" graben walls, indicating that the source of the water was probably at a depth greater than that of the graben (about 60 - 100 m). With due allowance for bulking and for errors of measurement, the volumes of the deposits are comparable to the volumes of their parent source depressions. We envisage that these deposits were created by phreatomagmatic explosions in which heat from a sill-like intrusion melts ice occupying pore space in crustal rocks and boils the resulting water. Calculations show that steam pressures of 1-3 MPa can readily loft the overburden from depths of a few hundred meters and lead to ejecta speeds greater than 100 m/s. Condensation of the water vapor during the explosion process leads to emplacement of a wet deposit, and plausible variations in ice content of the crustal rocks explain the sediment load variations.

Trans-Spatial Utopias

ERIC Educational Resources Information Center

Kramsch, Claire

2018-01-01

The "trans-" perspectives offered in this special issue are heady stuff. Post-structuralism (philosophy) meets the digital age (electronics), meets globalization (economics), and meets translingual practice (linguistics) to create a perfectly utopian or placeless space for future exploration. I want to first add my voice to the…

Geology of the V28 Quadrangle: Hecate Chasma, Venus

NASA Technical Reports Server (NTRS)

Stofan, E. R.; Guest, J. E.; Brian, A. W.

2000-01-01

The Hecate Chasma Quadrangle (V28), mapped at 1:5,000,000 scale, extends from 0-25 N and 240-270 Longitude. The quadrangle has thirteen impact craters, several large volcanoes, many coronae, three chasmata, and northern Hinemoa Planitia.

Ripples and Dunes

NASA Image and Video Library

2006-05-27

This MOC image shows dark sand dunes on the floor of an impact crater west of Hellas Planitia. Portions of the crater floor are exposed near the center and lower right corner of the image but, in general, the floor is covered by large, windblown ripples

Volcanic cones in Hydraotes chaos : implications for the chaotic terrains formation

NASA Astrophysics Data System (ADS)

Meresse, S.; Costard, F.; Mangold, N.; Masson, P.; Neukum, G.

2006-12-01

Numerous geologic scenarios have been proposed for the chaotic terrains formation. They include (1) sub-ice volcanism and other magma-ice interactions and (2) catastrophic release of groundwater from confined aquifers. The lack of volcanic morphology in the chaos was an handicap for the hypothesis of magma-ice interactions but the HRSC (High Resolution Stereo Camera) images have recently revealed possible volcanic cones inside the Hydraotes chaos. About thirty cones lie on the lowest parts of the chaos at elevation between -4300 and -5100 meters. They have basal diameters of 500-1900 m and heights exceeding 100 m. They are observed on young surface: the south smooth floor and inside the narrow valleys separating the mesas. The cones are relatively fresh. Similar morphologies of small cone-shaped structures have been previously identified in the northern lowlands of Mars (Chryse, Acidalia, Amazonis, Isidis and Elysuim Planitia) but their origin remains uncertain. A number of volcanic or cold climate landforms were proposed as potential terrestrial analogues : Icelandic pseudocraters (or rootless cones), cinder cones, tuff cones, pingos and spatter cones. The morphologic measurements made on the Hydraotes cones argue rather for a volcanic origin in comparison with terrestrial analogues. These first volcanic cones observed in Hydraotes chaos suggest that volcanic or subvolcanic activity might have played an important part in the chaotic terrains formation and outflow channels genesis.

The Pragmatic University: A Feasible Utopia?

ERIC Educational Resources Information Center

Badley, Graham

2016-01-01

"Imaginings" of the modern university include such ideas as "the ecological university" and "the pragmatic university". In his attempt to separate utopian from dystopian visions of the university, Ronald Barnett concentrates on an analysis of the ecological university and ignores, for example, the case of the…

Vulcan Planitia, Type Example of Outer Solar System Ammonia-Water Cryovolcanism

NASA Astrophysics Data System (ADS)

McKinnon, W. B.; Beyer, R. A.; Schenk, P. M.; Moore, J. M.; Singer, K. N.; White, O. L.; Spencer, J. R.; Cook, J. C.; Grundy, W. M.; Cruikshank, D. P.; Weaver, H. A.; Young, L. A.; Olkin, C. B.; Stern, S. A.; Robbins, S. J.; New Horizons GGI Team; New Horizons Composition Team

2018-06-01

Pluto's moon Charon offered the first clear (ground-based) evidence for the ammonia-water volcanism predicted long ago by J.S. Lewis. New Horizons then obtained compelling evidence for an ammonia-bearing cryovolcanic plain. But how did it get there?

Geologic Mapping of Ejecta Deposits in Oppia Quadrangle, Asteroid (4) Vesta

NASA Technical Reports Server (NTRS)

Garry, W. Brent; Williams, David A.; Yingst, R. Aileen; Mest, Scott C.; Buczkowski, Debra L.; Tosi, Federico; Schafer, Michael; LeCorre, Lucille; Reddy, Vishnu; Jaumann, Ralf;

Thermal convection as a possible mechanism for the origin of polygonal structures on Pluto's surface

NASA Astrophysics Data System (ADS)

Vilella, Kenny; Deschamps, Frédéric

2017-05-01

High-resolution pictures of Pluto's surface obtained by the New Horizons spacecraft revealed, among other surface features, a large nitrogen ice glacier informally named Sputnik Planitia. The surface of this glacier is separated into a network of polygonal cells with a wavelength of ˜20-40 km. This network is similar to the convective patterns obtained under certain conditions by laboratory experiments, suggesting that it is the surface expression of thermal convection. Here we investigate the surface planform obtained for different convective systems in 3-D Cartesian geometry with different modes of heating and rheologies. We find that bottom heated systems, as assumed by previous studies, do not produce surface planforms consistent with the observed pattern. Alternatively, for a certain range of Rayleigh-Roberts number, RaH, a volumetrically heated system produces a surface planform similar to this pattern. We then combine scaling laws with values of RaH within its possible range to establish relationships between the critical parameters of Sputnik Planitia. In particular, our calculations indicate that the glacier thickness and the surface heat flux are in the ranges 2-10 km and 0.1-10 mW m-2, respectively. However, a difficulty is to identify a proper source of internal heating. We propose that the long-term variations of surface temperature caused by variations in Pluto's orbit over millions of years produces secular cooling equivalent to internal heating. We find that this source of heating is sufficient to trigger thermal convection, but additional investigations are needed to determine under which conditions it can produce surface patterns similar to those of Sputnik Planitia.

Arecibo radar imagery of Mars: II. Chryse-Xanthe, polar caps, and other regions

NASA Astrophysics Data System (ADS)

Harmon, John K.; Nolan, Michael C.

2017-01-01

We conclude our radar imaging survey of Mars, which maps spatial variations in depolarized radar reflectivity using Arecibo S-band (λ12.6 cm) observations from 2005-2012. Whereas our earlier paper (Harmon et al., 2012, Arecibo radar imagery of Mars: the major volcanic provinces. Icarus 220, 990-1030) covered the volcanic regions of Tharsis, Elysium, and Amazonis, this paper includes non-volcanic regions where hydrologic and impact processes can be the dominant resurfacing agents affecting radar backscatter. Many of the more prominent and interesting radar-bright features outside the major volcanic provinces are located in and around Chryse Planitia and Xanthe Terra. These features are identified with: a basin in northeast Lunae Planum containing the combined deposits from Maja Vallis and Ganges Catena outflows; channel outwash plains in western and southern Chryse basin; plateaus bordering chasma/chaos zones, where surface modification may have resulted from hydrologic action associated with incipient chaos formation; and some bright-ejecta craters in Chryse basin, of a type otherwise rare on Mars. Dark-halo craters have also been identified in Chryse and elsewhere that are similar to those seen in the volcanic provinces. Although the cratered highlands are relatively radar-bland, they do exhibit some bright depolarized features; these include eroded crater rims, several unusual ejecta flows and impact melts, and terrain-softened plains. The rims of large impact basins (Hellas, Argyre, Isidis) show a variety of radar-bright features provisionally identified with massif slopes, erosion sediments, eroded pyroclastics, impact melts, and glacial deposits. The interiors of these basins are largely radar-dark, which is consistent with coverage by rock-free sediments. Tempe Terra and Acheron Fossae show bright features possibly associated with rift volcanism or eroded tectonic structures, and northwest Tempe Terra shows one very bright feature associated with glacial or other ice processes in the dichotomy boundary region. The first delay-Doppler images of the radar-bright features from the north and south polar icecaps are presented. Both poles show the circular polarization inversion and high reflectivity characteristic of coherent volume backscatter from relatively clean ice. The south polar feature is primarily backscatter from the residual CO2 icecap (with a lesser contribution from the polar layered deposits), whose finite optical depth probably accounts for the feature's strong S/X-band wavelength dependence. Conversely, the north polar radar feature appears to be mostly backscatter from the H2O-ice-rich polar layered deposits rather than from the thin residual H2O cap. The north polar region shows additional radar-bright features from Korolev Crater and a few other outlying circumpolar ice deposits.

Identification of Volcanic Landforms and Processes on Earth and Mars using Geospatial Analysis (Invited)

NASA Astrophysics Data System (ADS)

Fagents, S. A.; Hamilton, C. W.

2009-12-01

Nearest neighbor (NN) analysis enables the identification of landforms using non-morphological parameters and can be useful for constraining the geological processes contributing to observed patterns of spatial distribution. Explosive interactions between lava and water can generate volcanic rootless cone (VRC) groups that are well suited to geospatial analyses because they consist of a large number of landforms that share a common formation mechanism. We have applied NN analysis tools to quantitatively compare the spatial distribution of VRCs in the Laki lava flow in Iceland to analogous landforms in the Tartarus Colles Region of eastern Elysium Planitia, Mars. Our results show that rootless eruption sites on both Earth and Mars exhibit systematic variations in spatial organization that are related to variations in the distribution of resources (lava and water) at different scales. Field observations in Iceland reveal that VRC groups are composite structures formed by the emplacement of chronologically and spatially distinct domains. Regionally, rootless cones cluster into groups and domains, but within domains NN distances exhibit random to repelled distributions. This suggests that on regional scales VRCs cluster in locations that contain sufficient resources, whereas on local scales rootless eruption sites tend to self-organize into distributions that maximize the utilization of limited resources (typically groundwater). Within the Laki lava flow, near-surface water is abundant and pre-eruption topography appears to exert the greatest control on both lava inundation regions and clustering of rootless eruption sites. In contrast, lava thickness appears to be the controlling factor in the formation of rootless eruption sites in the Tartarus Colles Region. A critical lava thickness may be required to initiate rootless eruptions on Mars because the lava flows must contain sufficient heat for transferred thermal energy to reach the underlying cryosphere and volatilize buried ground ice. In both environments, the spatial distribution of rootless eruption sites on local scales may either be random, which indicates that rootless eruption sites form independently of one another, or repelled, which implies resource limitation. Where competition for limited groundwater causes rootless eruption sites to develop greater than random NN separation, rootless eruption sites can be modeled as a system of pumping wells that extract water from a shared aquifer, thereby generating repelled distributions due to non-initiation or early cessation of rootless explosive activity at sites with insufficient access to groundwater. Thus statistical NN analyses can be combined with field observations and remote sensing to obtain information about self-organization processes within geological systems and the effects of environmental resource limitation on the spatial distribution of volcanic landforms. NN analyses may also be used to quantitatively compare the spatial distribution of landforms in different planetary environments and for supplying non-morphological evidence to discriminate between feature identities and geological formation mechanisms.

Education, Erasmian Humanism and More's "Utopia"

ERIC Educational Resources Information Center

Parrish, John M.

2010-01-01

The humanist movement of the Northern Renaissance--often called "Christian humanism" or "Erasmian humanism" (after its most famous member, Desiderius Erasmus)--had a lasting impact on many areas of European intellectual and cultural life. This paper reviews the contribution of Erasmus and his circle to the theory and practice…

Classical Music as Enforced Utopia

ERIC Educational Resources Information Center

Leech-Wilkinson, Daniel

2016-01-01

In classical music composition, whatever thematic or harmonic conflicts may be engineered along the way, everything always turns out for the best. Similar utopian thinking underlies performance: performers see their job as faithfully carrying out their master's (the composer's) wishes. The more perfectly they represent them, the happier the…

Toward a Critical Utopian and Pedagogical Methodology

ERIC Educational Resources Information Center

Firth, Rhiannon

2013-01-01

This article explores the possibility of developing an ethico-politically coherent and practical research framework for studying the learning and knowledge-production and dissemination processes of utopian groups and movements. It seeks to develop understanding of utopias by identifying and conceptualizing their pedagogical aspects. At the same…

Sendero Luminoso: Case Study in Insurgency

DTIC Science & Technology

1993-01-01

utopia is premised on the spiritual rejuvenation of its chosen people, the Quechua -speaking "cosmic race." This messianic movement seeks to cleanse Peru...The Quechua -speaking top echelon also provided a link with the Indian masses whom Guzman hoped to politicize. At the same time, however, his

Chronicle of Higher Education. Volume 51, Number 19, January 14, 2005

ERIC Educational Resources Information Center

Chronicle of Higher Education, 2005

2005-01-01

"Chronicle of Higher Education" presents an abundant source of news and information for college and university faculty members and administrators. This January 14, 2005 issue of "Chronicle for Higher Education" includes the following articles: (1) "Utopia College: A Distinctive Alternative" (Nemko, Marty); (2)…

Social Actualization: A Theory of Community Living Arrangements and a Practical Utopia.

ERIC Educational Resources Information Center

Slawski, Carl

Characteristics of successful living arrangements in intentional communities are presented by examining kibbutz life. The first section discusses four bases for establishing and maintaining an intentional community: interest, justice, cultural flowering, and love (deep interpersonal and intergroup relationships and religious values). The second…

Geologic Mapping of the Beta-Atla-Themis (BAT) Region of Venus: A Progress Report

NASA Technical Reports Server (NTRS)

Bleamaster, Leslie F., III

2009-01-01

The BAT province is of particular interest with respect to evaluating Venus geologic, tectonic, and volcanic history and provides tests of global paradigms regarding her thermal evolution. The BAT is "ringed" by volcano-tectonic troughs (Parga, Hecate, and Devana Chasmata), has an anomalously high-density of volcanic features with concentrations 2-4 times the global average [1], and is spatially coincident with "young terrain" as illustrated by Average Surface Model Ages [2, 3]. The BAT province is key to understanding Venus current volcanic and tectonic modes, which may provide insight for evaluating Venus historical record. Several quadrangles, two 1:5,000,000 scale - Isabella (V-50) Quadrangle and Devana Chasma (V-29) Quadrangle and two 1:10,000,000 scale - Helen Planitia (I-2477) and Guinevere Planitia (I-2457), are in various stages of production (Figure 1). This abstract will report on their levels of completion as well as highlight some current results and outstanding issues.

Geologic Map of the Diana Chasma Quadrangle (V-37), Venus

USGS Publications Warehouse

Hansen, V.L.; DeShon, H.R.

2002-01-01

Diana Chasma quadrangle hosts some of the steepest topography on Venus. Altimetry measurements range from -2.5 to 4.7 km (0.0 = mean planetary radius), with a surface mean of 0.6 km. Fractures and faults within the central fracture/rift zone create large blocks of down-dropped material, especially along the east-central edge of the map area. The Dali and Diana chasmata display slopes of >30°, the steepest and deepest trenches on Venus. Both chasmata host landslide deposits presumably sourced from the steep chasmata walls. The tessera inlier, coronae, and ridge belts sit topographically above Rusalka and Zhibek planitiae. Rusalka Planitia topography describes broad undulations having northwest-trending ridges spaced ~200 km apart. The most distinctive ridge, Vetsorgo Dorsum, centered at 6.5° S., 163° E., is a Class I ridge belt owing to its simple arch morphology. The central interior of Markham crater sits topographically lower than the surrounding region, which slopes downward to the east.

Geologic Map of the Helen Planitia Quadrangle (V-52), Venus

USGS Publications Warehouse

Lopez, Ivan; Hansen, Vicki L.

2008-01-01

The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the Venusian atmosphere on October 12, 1994. Magellan Mission objectives included (1) improving the knowledge of the geological processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving the knowledge of the geophysics of Venus by analysis of Venusian gravity. The Helen Planitia quadrangle (V-52), located in the southern hemisphere of Venus between lat 25 deg S. and 50 deg S. and between long 240 deg E. and 270 deg E., covers approximately 8,000,000 km2. Regionally, the map area is located at the southern limit of an area of enhanced tectonomagmatic activity and extensional deformation, marked by a triangle that has highland apexes at Beta, Atla, and Themis Regiones (BAT anomaly) and is connected by the large extensional belts of Devana, Hecate, and Parga Chasmata. The BAT anomaly covers approximately 20 percent of the Venusian surface.

Utopian Education and Anti-Utopian Anthropology

ERIC Educational Resources Information Center

Papastephanou, Marianna

2013-01-01

This article explores the connection of education, utopia and anthropology, aiming to tease out some educational implications of anti-utopian anthropological essentialism and to show why these should be staved off. It will be shown how an anthropology that tarnishes human nature operates and how it affects educational intervention in the shaping…

A Paradoxical Academic Identity: Fate, Utopia and Critical Hope

ERIC Educational Resources Information Center

Sutton, Paul

2015-01-01

Using a dialectical mode of exposition, I offer a reflexive sociological theorisation of the paradox that characterises my academic identity: a fatalistic disenchantment concerning the colonisation of Higher Education (HE) by neoliberalism co-exists with a utopianism concerning HE's emancipatory possibilities. I begin with a discussion of Weber's…

Project Solo; Newsletter Number Four.

ERIC Educational Resources Information Center

Pittsburgh Univ., PA. Project Solo.

A paper titled "Myopia, Cornucopia and Utopia" makes up the major portion of this Project Solo Newsletter. It emphasizes the danger involved in the belief that the larger the system the better, and points out that although the computer utilizes technology, the human with judgment utilizes the computer. Some details of the Project Solo…

An Analytical Index to the Internet: Dreams of Utopia.

ERIC Educational Resources Information Center

Casey, Carol

1999-01-01

Explores the need for analytical indexes to access Internet resources. Considers bibliographic control, Web site design, keyword search engines, hierarchical subject indexes, and special indexes and compilations of links, and concludes that the creation of small, focused indexes may be the best solution for accessing specific types of digital…

A Heterotopology of the Academy: Mapping Assemblages as Possibilised Heterotopias

ERIC Educational Resources Information Center

Charteris, Jennifer; Jones, Marguerite; Nye, Adele; Reyes, Vicente

2017-01-01

Heterotopias are counter-sites of enacted utopias through which reality is simultaneously represented, contested and inverted. They are physical or mental spaces where, although norms of behaviours are suspended, there are connections with a plethora of other spaces. This article constructs a collective biography as a heterotopology of the…

UNESCO, the Faure Report, the Delors Report, and the Political Utopia of Lifelong Learning

ERIC Educational Resources Information Center

Elfert, Maren

2015-01-01

Two education reports commissioned by the United Nations Educational, Scientific and Cultural Organization (UNESCO), Learning to be, otherwise known as the "Faure report" (1972) and "Learning: The treasure within," otherwise known as the "Delors report" (1996), have been associated with the establishment of lifelong…

The Kibbutz in the 1970's: From Utopia Towards Modernization.

ERIC Educational Resources Information Center

Rayman, Paula

The document examines the evolution of kibbutzim in Israel. The author suggests that a primary factor in the kibbutz development is the nature and structure of Israeli modernization efforts. The efforts encompass national ideology, industrialization, and legitimization of certain forms of social interaction. This mode of modernization stands in…

We, John Dewey's Audience of Today

ERIC Educational Resources Information Center

da Cunha, Marcus Vinicius

2016-01-01

This article suggests that John Dewey's "Democracy and Education" does not describe education in an existing society, but it conveys a utopia, in the sense coined by Mannheim: utopian thought aims at instigating actions towards the transformation of reality, intending to attain a better world in the future. Today's readers of Dewey (his…

Learning, Change, and the Utopia of Play

ERIC Educational Resources Information Center

Moulthrop, Stuart

2007-01-01

This article looks at some of the rhetoric surrounding video games and other forms of interactive software as additions or alternatives to school curricula. It focuses particularly on the need to articulate ways to "read" videogames in order to achieve significant cultural impact. Noting that reading, even as metaphor, tends to invoke…

Human Rights, Cosmopolitanism and Utopias: Implications for Citizenship Education

ERIC Educational Resources Information Center

Starkey, Hugh

2012-01-01

Citizenship education, defined as learning to live together, requires agreement on certain common principles. One central purpose of a state education system is the transmission of common normative standards such as the human rights and fundamental freedoms that underpin liberal democratic societies. The paper identifies the conceptual roots of…