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Mineralogy of the Greenheugh Pediment and Underlying Murray Formation from the Mars Science Laboratory CheMin Instrument

The Mars Science Laboratory Curiosity rover has been investigating a sequence of ancient fluvio-lacustrine and eolian units in Gale crater. For much of the mission, Curiosity has studied the fluvio-lacustrine deposits of the Murray formation. Curiosity has also studied the ancient eolian Stimson formation in a few locations, which unconformably overlies the Murray fm. The Stimson formation was previously studied at the Naukluft and Emerson Plateaus and recently studied at the Greenheugh pediment capping unit. The Curiosity science team also investigated the Murray formation directly underlying the pediment. Curiosity drilled the “Edinburgh” target within the pediment capping unit and the “Hutton” target in the Murray formation near the contact with the pediment and delivered these materials to the CheMin X-ray diffractometer to characterize bulk mineralogy. Edinburgh contains abundant plagioclase, pyroxene, magnetite, olivine, and X-ray amorphous materials, with 10 wt.% smectite and minor sanidine. The mineralogy of the Stimson at Greenheugh is distinct from the mineralogy of the Stimson at Naukluft and Emerson because previous Stimson targets did not contain olivine or clay minerals. This suggests sediments in the pediment may have a different source and/or different aqueous alteration history than those from Naukluft and Emerson. Hutton contains abundant plagioclase, pyroxene, magnetite, and X-ray amorphous materials, 6 wt.% smectite, and minor cristobalite, opal-CT, sanidine, hematite, fluorapatite, and anhydrite. Other Murray targets in the surrounding Glen Torridon region that are farther from the pediment contact contain ~30 wt.% smectite and lack cristobalite and opal-CT. Cristobalite and/or opal-CT are present in a few other targets elsewhere along the traverse, including the top of the nearby Vera Rubin ridge and the top of the Pahrump Hills outcrop. Stimson overlies the Pahrump Hills, and, based on projections of the pediment slope, the Stimson may have overlain Vera Rubin ridge. The proximity of the low-smectite and cristobalite- and/or opal-CT-bearing outcrops to the contact between the Murray and Stimson suggests the contact provided a conduit for diagenetic fluids that altered clay minerals and formed crystalline and paracrystalline silica.

E. B. Rampe↗

NASA NTRS1972

Directions of strong winds on Mars inferred

Asymmetrical crater shadings and diffuse light and dark streaks visible on the photography returned by the 1969 Mars flyby of Mariners 6 and 7 are probably eolian in origin. Wind directions inferred from mapping of these features parallel motions of observed global dust storms or relate to expected patterns of topographic funneling of winds.

Howard, A. D.↗

NASA NTRS1972

Dynamics of plankton populations in upwelling areas

There are no author-identified significant results in this report. Repeated coverage over the test site along the northwest coast of Africa showed that the structure of chlorophyll distribution is much more complicated than expected from continuous recordings. ERTS-1 data showed a very fast change in the chlorophyll distribution and it seems that also the concentration changes quickly. ERTS-1 showed on some frames offshore transportation of dust from the Sahara. All frames from Channel 7 will be arranged as a montage to derive the transportation pattern of dust. This step is important in biological aspects of interpreting ERTS-1 data, because the dissolution kinetics of eolian dust particles may influence significantly the chemistry of the surface water. Since visibility and the biochemistry of the test site off Africa are influenced by the dust transport, dust collection will be included in the ground truth program. Besides chlorophyll and other hydrographical parameters, the dust load in the test area will be measured. The collection plan is discussed along with a description of the high volume air sampler and the Anderson particle sizing head sampler to be used for the dust measurements.

Szekielda, K.↗

NASA NTRS1973

Major crustal fractures in the Baltic Shield

The author has identified the following significant results. Black and white prints and transparencies of images 1039-09315, 1039-09322, and 1040-09371 with all bands of MSS have been used for the analyses. Bands 4 and 5 reveal the major urban areas, agricultural and timbering areas, highways as well as airfields, and an open pit mine. Even the border between Norway and Finland is clearly visible. Lakes, rivers, and wet swamps were best discerned on IR bands 6 and 7. Block fields formed by frost action are best seen on bands 4 and 5. The ancient shoreline on image 1039-09322 is seen as a narrow block field on bands 4 and 5. The effects of the Quaternary ice sheet on the morphography can be seen quite well in the images. The peat bogs are best seen in band 5, but can also be traced in bands 6 and 7. Eskers, glaciofluvial deposits, and deltas are distinguishable in bands 4 and 5, but can be traced in places also in the IR bands. Fluvial deposits are seen in the image 1039-09322 in the valleys of the Tornio and Kemi Rivers. They are easily discerned in bands 4 and 5, evidently because of the cultivated fields and pasture lands. Bands 4, 5, and 6 of image 1039-09315 reveal parts of eskers and glaciofluvial deltas which are affected by eolian activity. It seems evident that ERTS-1 imagery will be a great help in mapping Quaternary features.

Tuominen, H. V.↗

NASA NTRS1973

An overview of geologic results from Mariner 9

A summary of Mariner 9 mission operations insofar as they affected acquisition of geologic data is reported. Selected results with a minimum of supporting evidence are presented to give the geologic highlights of the mission. Volcanic features, tectonic features, channels, polar features, eolian features, impact craters, and the geological history of Mars are outlined.

Masursky, H.↗

NASA NTRS1973

Mariner 9 evidence for wind erosion in the equatorial and mid-latitude regions of Mars

Evidence for extensive wind erosion principally in the equatorial and mid-latitude regions of Mars is presented and compared with selected erosional landforms from the coastal desert of Peru known to be of eolian origin. The evidence for widespread erosion on Mars prompted an examination of certain aspects of its wind regime that are thought to be significant geologically.

Mccauley, J. F.↗

NASA NTRS1973

Mariner 9 observations of the surface of Mars in the north polar region

The recession rate of the north polar cap, as monitored by Mariner 9, was not significantly different than has been observed from earth in the past. Thus, the dynamic planet-wide dust storm does not seem to have had a noticeable effect on the thickeness of the CO2 deposit which developed during the standard mission. The dominant role of local topography in controlling the configuration of the retreating cap is confirmed. At narrow-angle resolution the retreating frost has high-lighted topographic detail that may represent Martian polar eolian deposits. At wide angle resolution the topography of the smooth plains, rugged etch pitted terrain, and complex central polar deposits is emphasized by the frost.

Soderblom, L. A.↗

NASA NTRS1973

Wind erosion in the Martian polar regions

Photographic evidence suggests that many topographic features of the polar regions of Mars may have been sculptured by wind action. In the case of the pitted terrain, this is established by relating the orientations of elongate basins and grooves to patterns of albedo markings that are generally accepted to be wind-formed. Small-scale flutes and other textures of laminated terrain recognized outside the perennial ice cap in the south polar region are also attributed to eolian action. Winds flowing off the polar cap and spiraling toward the west seem to be responsible. More speculatively the large-scale circumpolar features which underlie the residual polar caps may be related to wind erosion. Rotational motion localized on circular segments of the perennial frost deposits are proposed as a mechanism.

Cutts, J. A.↗

NASA NTRS1973

Mars: South polar pits and etched terrain

Martian south polar pits and etched terrain attest to alternating episodes of eolian deposition and erosion. Sometimes the south polar area has served as a sump for the accumulation of airborne debris and associated particles of frozen volatiles. At other times, the wind patterns or wind effectiveness change, and the atmosphere begins to remove the blanket of material it has earlier spread over the south polar region.

Sharp, R. P.↗

NASA NTRS1972

Preliminary Mariner 9 report on the geology of Mars.

Mariner 9 results indicate that Mars is geologically far more heterogeneous than previously suspected from earlier flyby missions; the surface has been shaped by volcanic, tectonic, erosional, and depositional activity. The equatorial region between 30 deg N and 30 deg S latitude is depicted in four geologic sketch maps, and seventeen geologic units are defined on the basis of their textural characteristics. The maps and the brief descriptions of geological units portrayed are followed by a series of more interpretive discussions dealing with topical problems and a summary geologic history. Topics covered include cratering, circular basins, volcanism, canyons, chaotic terrain, channels, and eolian activity.

Mccauley, J. F.↗

NASA NTRS1973

A generalized geologic map of Mars.

A geologic map of Mars has been constructed largely on the basis of photographic evidence. Four classes of units are recognized: (1) primitive cratered terrain, (2) sparsely cratered volcanic eolian plains, (3) circular radially symmetric volcanic constructs such as shield volcanoes, domes, and craters, and (4) tectonic erosional units such as chaotic and channel deposits. Grabens are the main structural features; compressional and strike slip features are almost completely absent. Most grabens are part of a set radial to the main volcanic area, Tharsis.

Carr, M. H.↗

NASA NTRS1973

Latitudinal distribution of a debris mantle on the Martian surface.

Mariner 9 narrow angle pictures show that many areas on Mars are buried by debris mantles that later have been partially eroded. A survey of the present debris distributions shows that they are symmetrically disposed about the polar regions, extending poleward from the 30 N and 30 S latitudes. These blankets are inferred to represent eolian debris derived from circumpolar layered deposits; the process of equatorward redistribution of debris by wind action is probably still continuing.

Soderblom, L. A.↗

NASA NTRS1973

Mariner 9 observations of the surface of Mars in the north polar region.

During the Mariner 9 extended mission the recession of the north polar ice caps was monitored for 130 days. The edge of the cap displayed a peculiar polygonal outline during most of this period. Regional topographic control is suggested as the most likely cause of the polygonality. Whereas densely cratered terrain dominates the south polar region, moderately cratered plains underlie the polar deposits in the north polar region. The mottled cratered plains have been mantled by light deposits located in annular rings south of 70 N. The erosional boundaries between these deposits and the subjacent cratered plains are gradational, show no local topographic relief, and display a spiral serrated circumpolar pattern suggesting eolian erosion. Smooth plains and 'etch-pitted' plains underlie the central polar layered deposits in both polar regions. In addition, these plains have one other morphological variant in the north. Here they display a pattern of very coherent ripple-like waveforms varying in wavelength from several hundred meters to a few kilometers.

Soderblom, L. A.↗

NASA NTRS1973

Photogeologic mapping of Meridiani Sinus region from Mariner 6 and 7 imagery

Photogeologic mapping of Mariner photographs characterizes major stratigraphic units of the Martian equatorial region. The low resolution photomosaic ship across Meridiani Sinus Deucalionus Regio is divided into regional map units based on albedo and crater density. High resolution frames reveal map units defined by varying surface texture, crater densities, and degree of crater sharpness. Mariner photographs provide clear evidence of eolian action and channelization by fluid flow.

Dehon, R. A.↗

NASA NTRS1975

Particle motion in atmospheric boundary layers of Mars and Earth

To study the eolian mechanics of saltating particles, both an experimental investigation of the flow field around a model crater in an atmospheric boundary layer wind tunnel and numerical solutions of the two- and three-dimensional equations of motion of a single particle under the influence of a turbulent boundary layer were conducted. Two-dimensional particle motion was calculated for flow near the surfaces of both Earth and Mars. For the case of Earth both a turbulent boundary layer with a viscous sublayer and one without were calculated. For the case of Mars it was only necessary to calculate turbulent boundary layer flow with a laminar sublayer because of the low values of friction Reynolds number; however, it was necessary to include the effects of slip flow on a particle caused by the rarefied Martian atmosphere. In the equations of motion the lift force functions were developed to act on a single particle only in the laminar sublayer or a corresponding small region of high shear near the surface for a fully turbulent boundary layer. The lift force functions were developed from the analytical work by Saffman concerning the lift force acting on a particle in simple shear flow.

White, B. R.↗

NASA NTRS1975

The geology of Mars - A brief review of some recent results

Some Mariner 9 data on geologic provinces, volcanic processes, geophysical models, Eolian activity, surface water, and atmospheric composition on Mars are presented. Ways in which this data is expected to be augmented by the Viking mission are briefly reviewed. Information given in map form includes permanent ice, layered deposits, etched plains, volcanic constructs (shields, domes, or cones), volcanic plains, moderately cratered plains, cratered plains, hummocky terrain, channel deposit, undivided plains, and grooved terrain.

Mutch, T. A.↗

NASA NTRS1975

A size-frequency study of large Martian craters

The log normal frequency distribution law was used to analyze the crater population on the surface of Mars. Resulting data show possible evidence for the size frequency evolution of crater producing bodies. Some regions on Mars display excessive depletion of either large or small craters; the most likely causes of the depletion are considered. Apparently, eolian sedimentation has markedly altered the population of the small craters south of -30 deg latitude. The general effects of crater obliteration in the Southern Hemisphere appear to be confined to diameters of less than 20 km. A strong depletion of large craters in a large region just south of Deuteronilus Mensae, and in a small region centered at 35 deg latitude and 10 deg west longitude, may indicate locations of subsurface ice.

Woronow, A.↗

NASA NTRS1976

Albedo boundaries on Mars in 1972 - Results from Mariner 9

A map of 'albedo' boundaries (light and dark markings) on Mars was prepared from Mariner 9 images. After special digital processing, these pictures provide detailed locations of albedo boundaries, which is significant in interpreting recent eolian activity. Derivation of absolute albedo values from the spacecraft data was not attempted. The map correlates well with telescopic observations of Mars after the 1971 dust storm.

Batson, R. M.↗