Mega-ripples in Iran: A new analog for transverse aeolian ridges on Mars

Foroutan, M.; Zimbelman, J. R.

doi:10.1016/j.icarus.2016.03.025

Cited by 46 publications

(30 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reversing dunes form under a bidirectional wind regime, where the two dominant wind directions are opposite in direction. Foroutan and Zimbelman (2016) and . analyzed orbital images of TAR-like bedforms in the Lut desert in Iran and found them to closely resemble TARs morphologically and morphometrically.…”

Section: Tar Formation Theoriesmentioning

confidence: 99%

High-resolution investigations of Transverse Aeolian Ridges on Mars

Berman

Balme

Michalski

et al. 2018

Icarus

View full text Add to dashboard Cite

Transverse Aeolian Ridges (TARs) are the most pervasive aeolian feature on Mars. Their small size requires high-resolution data for thorough analyses. We have utilized Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) and High Resolution Image Stereo Experiment (HiRISE) images, along with MRO Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectroscopic data to study TARs in detail. TAR deposits, along with related dark dune material and layered terrains, have been mapped in six study areas in order to identify sediment pathways and determine whether TARs are sourced locally or from global wind-born materials. TAR morphology and orientation were mapped in grids within each study area; the results show that TARs are probably locally sourced. We constructed four HiRISE Digital Terrain Models (DTMs) to measure TAR heights, widths, spacing, areas, symmetry, and to calculate sediment volumes. Results show that TARs have average heights of ~1.5 m, are very symmetrical, and are similar in form to terrestrial megaripples. Orthorectified HiRISE images taken 3 years apart were analyzed for TAR movement and none was found. Superposed craters on equatorial TARs give ages of ~2 Ma, suggesting that these are relatively ancient and generally inactive aeolian deposits. CRISM data were analyzed over TAR deposits, dark dune material, and light-toned terrains. Although the surfaces were somewhat obscured by dust cover, the results did not show any remarkable difference between TARs and other deposits. We conclude that TARs may be sourced from local materials and form in a similar way to terrestrial megaripples.

show abstract

Section: Tar Formation Theoriesmentioning

confidence: 99%

High-resolution investigations of Transverse Aeolian Ridges on Mars

Berman

Balme

Michalski

et al. 2018

Icarus

View full text Add to dashboard Cite

show abstract

“…This work was focused on typical aeolian ripples with heights and lengths of the orders of 0.01 and 0.1 m, respectively, with mean grain sizes (d) between about 0.1 and 0.5 mm that we believe to be in equilibrium or near equilibrium with the wind. We did not consider megaripples [20][21][22] or transverse aeolian ridges [23][24][25], although both of these bed forms have received considerable and appropriate attention in the literature.…”

Section: Introductionmentioning

confidence: 99%

Aeolian Ripple Migration and Associated Creep Transport Rates

et al. 2019

View full text Add to dashboard Cite

Wind-formed ripples are distinctive features of many sandy aeolian environments, and their development and migration are basic responses to sand transport via saltation. Using data from the literature and from original field experiments, we presented empirical models linking dimensionless migration rates, urgd (ur is the ripple migration speed, g is the gravity acceleration, and d is the grain diameter) with dimensionless shear velocity, u*/u*t (u* is shear velocity and u*t is fluid threshold shear velocity). Data from previous studies provided 34 usable cases from four wind tunnel experiments and 93 cases from two field experiments. Original data comprising 68 cases were obtained from sites in Ceará, Brazil (26) and California, USA (42), using combinations of sonic anemometry, sand traps, photogrammetry, and laser distance sensors and particle counters. The results supported earlier findings of distinctively different relationships between urgd and u*/u*t for wind tunnel and field data. With our data, we could also estimate the contribution of creep transport associated with ripple migration to total transport rates. We calculated ripple-creep transport for 1 ≤ u*/u*t ≤ 2.5 and found that this accounted for about 3.6% (standard deviation = 2.3%) of total transport.

show abstract

“…TARs have decameter-scale wavelengths, intermediate between the small centimeter-scale wind ripples and the large kilometer-scale dunes [17]. TARs were first named by Bourke et al [18] and the precise information on their origin and sediment source, formation mechanisms, composition, distribution, activity, age, and superposition relationships are yet to be confirmed [19]. However, several interpretations [2,20] envisage them as granule ripples under a surface layer of mm-sized particles, too coarse to be moved by the present-day Martian winds [17].…”

Section: Introductionmentioning

confidence: 99%

Distribution and Morphologies of Transverse Aeolian Ridges in ExoMars 2020 Rover Landing Site

et al. 2019

View full text Add to dashboard Cite

Aeolian processes are believed to play a major role in the landscape evolution of Mars. Investigations on Martian aeolian landforms such as ripples, transverse aeolian ridges (TARs), and dunes, and aeolian sediment flux measurements are important to enhance our understanding of past and present wind regimes, the ongoing dust cycle, landscape evolution, and geochemistry. These aeolian bedforms are often comprised of loose sand and sharply undulating topography and thus pose a threat to mobility and maneuvers of Mars rovers. Here we present a first-hand account of the distribution, morphologies, and morphometrics of TARs in Oxia Planum, the recently selected ExoMars 2020 Rover landing site. The gridded mapping was performed for contiguous stretches of TARs within all the landing ellipses using 57 sub-meter high resolution imaging science experiment (HiRISE) scenes. We also provide the morphological descriptions for all types of TARs present within the landing ellipses. We use HiRISE digital terrain models (DTMs) along with the images to derive morphometric information for TARs in Oxia Planum. In general, the average areal TAR coverage was found to be 5.4% (±4.9% standard deviation), increasing from west to east within the landing ellipses. We report the average TAR morphometrics in the form of crest–ridge width (131.1 ± 106.2 m), down-wind TAR length (17.6 ± 10.1 m), wavelength (37.3 ± 11.6 m), plan view aspect ratio (7.1 ± 2.3), inter-bedform spacing (2.1 ± 1.1), slope (10.6° ± 6.1°), predominant orientations (NE-SW and E-W), and height (1.2 ± 0.8 m). While simple TARs are predominant, we report other TAR morphologies such as forked TAR, wavy TAR with associated smaller secondary ripples, barchan-like TAR, networked TAR, and mini-TARs from the region. Our results can help in planning the rover traverses in terms of both safe passage and scientific returns favoring aeolian research, particularly improving our understanding of TARs.

show abstract

Mega-ripples in Iran: A new analog for transverse aeolian ridges on Mars

Cited by 46 publications

References 17 publications

High-resolution investigations of Transverse Aeolian Ridges on Mars

High-resolution investigations of Transverse Aeolian Ridges on Mars

Aeolian Ripple Migration and Associated Creep Transport Rates

Distribution and Morphologies of Transverse Aeolian Ridges in ExoMars 2020 Rover Landing Site

Contact Info

Product

Resources

About