North Polar Region of Mars: Imaging Results from Viking 2

Cutts, J. A.; Blasius, K. R.; Briggs, G. A.; Carr, M. H.; Greeley, R.; Masursky, H.

doi:10.1126/science.194.4271.1329

Cited by 128 publications

(91 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dunes were first identified on Mars from Mariner 9 images (McCauley et al,1972;Cutts and Smith, 1973). Later, Mariner and Viking orbiter images revealed a series of extensive ergs around the north pole ice cap (Cutts et al, 1976;Tsoar et al, 1979) and large dune fields in craters in the southern hemisphere (Cutts and Smith, 1973;Thomas, 1981;Lancaster and Greeley, 1987).…”

Section: Introductionmentioning

confidence: 99%

Transverse Aeolian Ridges (TARs) on Mars

et al. 2008

View full text Add to dashboard Cite

Aeolian processes are probably the dominant ongoing surface process on Mars; Large Dark Dunes (LDDs), particularly common aeolian landforms, were first recognized in the early 1970s. Recent, higher resolution images have revealed another, morphologically distinct, large population of smaller, ripple-like aeolian bedforms that have been termed "Transverse Aeolian Ridges" (TARs) as it is unknown whether they formed as large ripples or small dunes. We have begun a new study of TARs that examines their distribution, orientation, and morphology using N 10,000 high-resolution Mars Orbiter Camera (1.5 to 8 m/pixel resolution) images in a 45°longitude wide, pole-to-pole survey. The aim of this study is to assess whether TARs are active, to identify possible sediment sources and pathways, and to determine the volumes of sediment that they comprise. We present results from the first half of this study, in which we examine the northern hemisphere, and describe a new three-part classification scheme used to aid the survey. Our results show that TARs are abundant but not ubiquitous: preferentially forming proximal to friable, layered terrains such as those found in Terra Meridiani -the location of the ongoing Mars Exploration Rover "Opportunity" mission. TAR distribution in the northern hemisphere shows a strong latitudinal dependence with very few TARs being found north of ∼ 30°N. We also find that in most cases TARs are less mobile than LDDs, a conclusion possibly explained by Mars Exploration Rover Opportunity observations that show TARlike ripples to have a core of fine material armored by a monolayer of granule-sized particles. This could disallow significant bedform movement under the current wind regime. That TARs are essentially inactive is confirmed by superposition relations with slope streaks and LDDs and by observations of superposed impact craters. We suggest that observations made by the Opportunity Rover in Terra Meridiani indicate that the small aeolian bedforms common here are ripples and not small dunes. Farther south, these bedforms transition into larger features indistinguishable from TARs, suggesting that TARs (in the Meridiani area at least) are ripples and not dunes.

show abstract

Section: Introductionmentioning

confidence: 99%

Transverse Aeolian Ridges (TARs) on Mars

et al. 2008

View full text Add to dashboard Cite

show abstract

“…The Martian polar layered deposits appear to record climate variations over at least the last 10 to 100 million years [Murray et al, 1972;Cutts, 1973;Cutts et al, 1976Cutts et al, , 1979 Dark dunes nearly surround the north polar layered deposits on Mars [Tsoar et al, 1979;Dial, 1984], forming a "sand sea" or "erg." By analogy with aeolian dunes on Earth, the dark dunes on Mars are believed to have been formed by saltation or traction of sand-sized particles in response to Martian winds.…”

Section: Introductionmentioning

confidence: 99%

Dark material in the polar layered deposits and dunes on Mars

Herkenhoff¹,

Vasavada²

1999

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

“…Cutts et al (1976) note that in an area of 8 x 1@ km 2 of layered terrain in the north, not one crater as large as 300 m was observed. If this lack of craters was due solely to age it would imply a surface less than 1 my old.…”

Section: Depositional Ratesmentioning

confidence: 99%

“…The layered deposits are believed to be accumulations of volatiles and dust with both the relative and absolute accumulation rate of each component being somehow modulated by climatic variations (Murray et al, 1972;Cutts, 1973;Cutts et al, 1976;Sharp, 1974). The summer remnant caps provide clues as to how the modulation might be effected.…”

Section: Climatic Variations As a Cause Of The Layeringmentioning

confidence: 99%

Periodic climate change on Mars: Review of evidence and effects on distribution of volatiles

Carr

1982

Icarus

Self Cite

View full text Add to dashboard Cite

The polar regions of Mars preserve, in both their layering and their topography, a record of recent climate changes. Because of the coincidence of the growth of the northern seasonal cap with global dust storms, dust may be currently accumulating on the northern cap, but conditions at the poles will alternate with the precessional cycle. Deposition is also modulated by changes in eccentricity and obliquity, which interact complexly, affecting initiation of global dust storms, the stability of volatiles at the surface, and global wind regimes. Formation of spiral valleys and low undulations on the surface of the layered deposits may result from preferential sublimation of volatiles on sunward-facing slopes and condensation on the adjacent flats, with the rates also modulated by astronomically caused insolation variations. Lack of impact craters on the surface and lack of interruption of the layers by impact scars suggest that the polar deposits are no more than a few million years old. Older deposits may have been periodically removed, as indicated by etch-pitted terrain at the south pole and by superposition relations around the periphery of the present layered deposits. Evidence of ancient periodic climate changes that occurred before formation of the present layered terrain is fragmentary but includes pedestal craters, parallel moraine-like ridges, and etched ground at high latitudes. Perturbation of the orbital motions also results in adsorption and desorption of volatiles in the regolith, which leads to variations in atmospheric pressure and partial dehydration of the equatorial near-surface materials.

show abstract

North Polar Region of Mars: Imaging Results from Viking 2

Cited by 128 publications

References 17 publications

Transverse Aeolian Ridges (TARs) on Mars

Transverse Aeolian Ridges (TARs) on Mars

Dark material in the polar layered deposits and dunes on Mars

Periodic climate change on Mars: Review of evidence and effects on distribution of volatiles

Contact Info

Product

Resources

About