Sand dunes are among the most widespread aeolian features present on Mars, serving as unique indicators of the interaction between the atmosphere and surface. On a planetary body, dunes accumulate where a supply of sand-sized grains exists or may be abraded, is carried downwind by winds of saltation strength, and is subsequently deposited where these winds weaken below the threshold for sand transport. As a result, the study of dune processes contributes to both atmospheric and sedimentary science. Both the presence and morphology of sand dunes are sensitive to subtle shifts in wind circulation patterns and wind strengths, which are thought to be influenced by changes in Martian orbital parameters. The spatial distribution of aeolian sand relates to patterns of sedimentary deposition and erosion of source materials, giving clues to the sedimentary history of the surrounding terrain. Dunes are particularly suited to comprehensive planetary studies in part because they are abundant on the Martian surface over a wide range of elevations and terrain types, and in part because they are large enough to be studied using the wide suite of spacecraft data now available. Thus a global scale study of Martian dunes serves a dual purpose in furthering understanding of both climatic and sedimentary processes, two fundamental topics currently driving Martian science.
This consortium and website were put together to facilitate exchange of information that pertains to Martian dune studies. Currently the consortium is made up of members from the USGS Astrogeology Team, Arizona State University, NASA Ames Research Center, and Planetary Science Institute.
Why Study Planetary Dunes?
Previous aeolian studies of the Martian surface relied on Mariner 9 and Viking Orbiter images to examine and map aeolian morphologies. More recent studies, using high-resolution images like Mars Global Surveyor (MGS) Mars Orbiter Camera narrow angle (MOC NA) and Mars 2001 Odyssey Orbiter Thermal Emission Imaging System (THEMIS) visible range images (VIS), have enabled scientists to re-examine surficial areas from earlier investigations and see new aeolian deposits unresolved by previous instruments. As a result of the influx of high resolution data, the Martian stratigraphic column is undergoing rapid evolution as are the interpretations of much of Mars' geologic history, contributing to new insights about Martian aeolian processes and relationships. Surface images from both orbiting spacecraft (e.g., from MGS MOC NA) and Mars Exploration Rovers (MER) demonstrate how ubiquitous erosional and depositional features of aeolian origin are on the Martian surface.
The Mars Global Digital Dune Database (MGD3)
Current releases of THEMIS infrared (IR) images (100 m/px resolution) provide nearly complete coverage of the Martian surface. As such, these images can robustly serve as a basis for a planet-wide inventory of moderate to large-scale dune deposits. Within a global context, dune forms and regional distributions can easily be compared to global datasets (e.g., Mars Orbiter Laser Altimeter (MOLA) elevations and Thermal Emission Spectrometer (TES) derived thermal inertia values) and models (e.g. General Circulation Models (GCMs)) to provide a better understanding of the planet-wide processes that have shaped the Martian surface.
The digital dune database makes it possible to look at dunes in a global context, comparing their geographic location and attributes to other global coverages, such as geologic maps, GCMs, MOLA and TES. Such comparisons provide significant perspective on local, regional, and global-scale aeolian processes that have shaped and continue to influence the surface of Mars.
The Mars Global Digital Dune Database has been one of the primary driving factors for the Mars-Dunes Consortium.
The MGD3 includes seven major data layers: 1) The Dune Field feature class (polygon) includes ~550 dune fields on Mars between +65 and -65. 2) The Crater feature class (polygon) includes ~ 400 craters on Mars between +65 and -65 that are occupied by dune fields in the database. 3) and 4) The Crater centroid to Dune centroid Azimuth feature class (polyline and point versions) is based on polylines that extend from crater centroid to the centroid of a dune field within the crater on Mars between +65 and -65. 5) The Raw Slipface feature class (polyline) includes >10,000 polylines that were digitized on slipfaces, based on gross morphology of dunes, to represent wind direction responsible for that morphology. 6) The Average Slipface Azimuth feature class (point) was created by averaging raw slipface azimuths for the ~ 200 dune fields in which measurements were possible. Dune fields with multidirectional winds have more than one average, resulting in ~270 average slipface azimuths. 7) The GCM feature class (polyline) represents output from the Ames Mars General Circulation Model (GCM) for the area from +70 to -70. Only output records with a shear stress value > .0225 N/m2 are included.
MGD3: Where are Dunes Found on Mars?
MGD3is complete for the +65 to -65 portion of Mars. The distribution of the dunes can be seen in the above map of that region (top). The database is in progress for the -65 to -90 portion of Mars. The distribution of possible dunes is shown in the table below. Based on possible dunes, the total dune field area in the -65 to -90 area is estimated to be about 50,000 km2. The map of +65 to +90, above right, shows the possible location of dunes. An areal estimate of dune fields is not yet available for that region.
|Latitudinal Region||Number of Dune Fields||% of Total Number of Dune Fields||Area of Dune Fields (km2)||% of Total Area|
|30° to 65° N||9||1.6||1507||2.2|
|0° to 30° N||36||6.6||5165||7.4|
|0° to 30° S||37||6.8||13,275||19.0|
|30° to 65° S||465||85.0||49,803||71.4|
The following table summarizes the geographic distribution of the dunes in the database, (+65 to -65) by latitudinal band. Remember that only moderate to large dune fields are included in this database. The distribution of smaller dune fields may not follow this pattern.
The following table summarizes the quantity of dune fields in craters by number of dune fields and by area of dune fields for the Latitudinal bands and for the Argyre, Hellas and Valles Marineris regions.
|Latitudinal Region||Number of Dune Fields||Area of Dune Fields (km2)||Number of Dune Fields in Craters||Area of Dune Fields in Craters (km2)||% of Dune Fields in Craters (by area)|
|0° to 30° S||37||13,275||17||4326||32.6|
|30° to 65° S||465||49,803||368||39,990||80.3|
|Argyre and surrounding rough terrain||47||5347||12||2453||45.9|
|Hellas and surrounding rough terrain||18||1310||2||87||6.6|
Thermal Emission Imaging System - Infrared Band (THEMIS IR)
THEMIS IR images were chosen because they provided planet-wide coverage of Mars at a resolution (100 m/pixel) capable of revealing many dune features. Due to small particle size, dunes have a lower thermal inertia than surrounding rock, accompanied by a large diurnal temperature change. The dunes are relatively warm in the daytime images, appearing light in tone, making them easy to detect. In nighttime images the pattern reverses with the relatively cool dunes appearing dark.
Thermal Emission Imaging System - Visible Band (THEMIS Vis)
The higher resolution THEMIS VIS images are used, when available, to verify that the features are dunes and to classify the dune types.
Mars Orbital Camera (MOC)
Because of the higher spacial resolution, MOC images are used to identify and analyize slip faces and dune types.
High Resolution Imaging Science Experiment (HiRISE)
Though HiRISE images have not yet been used on the MGD3, these images shoudl offer even higher resolution that will better identify dune types, and should be able to show improved detail within the dunes.
Compact Reconnaissance Imaging Spectrometer for Mars (CRISM)
CRISM images, like HiRISE, have not yet been used for the MGD3. Also like HiRISE though, CRISM will offer greater detail and a better understanding of the dunes on Mars.
Aeolian Abstracts and Papers
- Disappearing and shrinking dunes on Mars 2007-04 European Geophysical Union M. C. Bourke, K. S. Edgett, B. A. Cantor
- Mars Digital Dune Database: Progress and Application (in documentation) 2007-03 38th Lunar and Planetary Science Conference Abstract # 1360 R. K. Hayward, L. K. Fenton, T. N. Titus, T. M. Hare, K. F. Mullins, T. Colaprete, M. C. Bourke, P. R. Christensen
- Mars Digital Dune Database: More Preliminary Science Results (in documentation) 2007-03 38th Lunar and Planetary Science Conference LPI Contribution No. 1338, p.1486 L. K. Fenton, R. K. Hayward, K. F. Mullins, T. N. Titus, T. Colaprete
- Pilot Study of Higher Order Neighbor Statistics for Crescentic Dunes of the Martian North Polar Region 2007-03 38th Lunar and Planetary Science Conference LPI Contribution No. 1338, p.1414 A. J. Wheeler, M. A. Bishop
- Dark Dunes in Martian Craters 2007-03 38th Lunar and Planetary Science Conference LPI Contribution No. 1338, p.1569 D. Tirsch, R. Jaumann, D. Reiss, J. Helbert, F. Forget, E. Millour, F. Poulet, G. Neukum
- Stratigraphy and landscape evolution of Chasma Boreale 2007-03 38th Lunar and Planetary Science Conference Abstract # 1856 K. Tanaka, M. C. Bourke
- Constraints on the structure and composition of sand dunes within Olympia Undae using Mars Odyssey Neutron Spectrometer data (on the web) 2007-03 38th Lunar and Planetary Science Conference Abstract # 2311 W. C. Feldman, M. C. Bourke, R. C. Elphic, S. Maurice, T. H. Prettyman, D. J. Lawrence, J. J. Hagerty
- First Evidence of Dune Movement on Mars 2006-12 Eos, Transactions, American Geophysical Union, Fall MeetingAbstract # P31B-0128 M. C. Bourke, K. S. Edgett
- Dune migration and slip face advancement in the Rabe Crater dune field, Mars 2006-10 Geophysical Research Letters 33(20), L20201, doi: 10.1029/2006GL027133 L. K. Fenton
- A comparison of methods used to estimate the height of sand dunes on Mars 2006-09 Geomorphology 81 M. C. Bourke, M. Balm, R. Beyer, K. K. Williams, J. Zimbelman
- Barchan dune morphodynamics and linear dune formation on Mars 2006-07 Sixth International Conference of Aeolain Research, Guelph, Canada M. C. Bourke
- Transverse aeolian ridges (TARs) on Mars 2006-07 Sixth International Conference of Aeolain Research, Guelph, Canada M. Balm, D. C. Berman, M. C. Bourke
- Thermal properties of sand from Thermal Emission Spectrometer (TES) and Thermal Emission Imaging System (THEMIS): Spatial variations within the Proctor Crater dune field on Mars 2006-06 Journal of Geophysical Research 111(E6), E06014, doi:10.1029/2004JE002363 L. K. Fenton, M. T. Mellon
- A new model for linear dune formation: merged barchan convoys on Mars. 2006-03 37th Lunar and Planetary Science Conference Abstract # 1362 M. C. Bourke
- Potential sand sources for the dune fields in Noachis Terra, Mars 2005-11 Journal of Geophysical Research 110(E11), E11004, doi:10.1029/2005JE002436 L. K. Fenton
- Aeolian processes in Proctor Crater on Mars: Mesoscale modeling of dune-forming winds 2005-06 Journal of Geophysical Research 110(E6), E06005, doi:10.1029/2004JE002309 L. K. Fenton, A. D. Toigo, M. I. Richardson
- Alluvial fans on dunes in Kaiser Crater suggest niveo-aeolian and denivation processes on Mars 2005-03 36th Lunar and Planetary Science Conference Abstract # 2372 M. C. Bourke
- Preliminary results from a new study of transverse aeolian ridges (TARS) on Mars 2005-03 36th Lunar and Planetary Science Conference Abstract # 1892 M. Balm, M. C. Bourke
- Seasonal Movement of Material on Dunes in Proctor Crater, Mars: Possible Present-Day Sand Saltation 2005-03 36th Lunar and Planetary Science Conference Abstract #2169 L. K. Fenton
- Mars Digital Dune Database (in documentation) 2004-12 Eos, Transactions, American Geophysical Union, Fall MeetingSuppl., 85 (46), abstract P31B-0984. R. K. Hayward, T. N. Titus, K. F. Mullins, L. K. Fenton, M. C. Bourke, P. R. Christensen
- Niveo-aeolian and Denivation Deposits on Mars 2004-12 Eos, Transactions, American Geophysical Union, Fall MeetingAbstract # P21B-01 M. C. Bourke
- Dynamics of unusual debris flows on Martian sand dunes 2004-08 Geophysical Research Letters 31, 10.1029/2004GL020313 H. Miyamoto, J. M. Dohm, V. R. Baker, R. Beyer, M. C. Bourke
- Aeolian sediment transport pathways and aerodynamics at troughs on Mars 2004-07 Journal of Geophysical Research 109, E7, DOI:10.1029/2003JE002155. M. C. Bourke, J. Bullard, O. Barnouin-Jha
- A comparative analysis of barchan dunes in the intra-crater dune fields and the north polar sand sea 2004-03 35th Lunar and Planetary Science Conference Abstract # 1453 M. C. Bourke, M. Balm, J. Zimbelman
- Thermal Properties of Sand from TES and THEMIS: Do Martian Dunes Make a Good Control for Thermal Inertia Calculations? 2004-03 35th Lunar and Planetary Science Conference Abstract #1974 L. K. Fenton, R. L. Fergason
- Aeolian processes in Proctor Crater on Mars: Sedimentary history as analyzed from multiple data sets 2003-12 Journal of Geophysical Research 108(E12), 5129, doi:10.1029/2002JE002015 L. K. Fenton, J. L. Bandfield, A. W. Ward
- Temporal Invariance of Wind Orientations as Recorded by Aeolian Features in Proctor Crater 2003-07 Sixth International Conference on Mars, Pasadena, CA, USAAbstract #3267 L. K. Fenton, M. I. Richardson, A. D. Toigo
- Gone but not forgotten: the aeolian modification of fluvial surfaces on Mars. 2003-03 34th Lunar and Planetary Science Conference Abstract # 1643 M. C. Bourke
- The variability of transverse aeolian ridges in troughs on Mars 2003-03 34th Lunar and Planetary Science Conference Abstract # 2090 M. C. Bourke, S. A. Wilson, J. Zimbelman
- Sand Transport in Proctor Crater on Mars Based on Dune Morphology and Mesoscale Modeling 2002-03 33rd Lunar and Planetary Science Conference Abstract #1953 L. K. Fenton, M. I. Richardson, A. D. Toigo
- Martian surface winds: Insensitivity to orbital changes and implications for aeolian processes 2001-12 Journal of Geophysical Research 106(E12), p. 32,885-32,902, doi:10.1029/2000JE001407 L. K. Fenton, M. I. Richardson
- Global Martian Sand Transport as Predicted by the GDFL Mars GCM 2000-03 31st Lunar and Planetary Science Conference Abstract #2072 L. K. Fenton, M. I. Richardson
- Longitudinal dunes on Mars: Relation to current wind regimes 1995-03 Journal of Geophysical Research Vol. 100, no. E3, p. 5381-5395 P. Lee, P. C. Thomas
- The particle size of Martian aeolian dunes 1991-12 Journal of Geophysical Research vol. 96, Dec. 25, 1991, p. 22,765-22,776 K. S. Edgett, P. R. Christensen
- Speculation on Martian north polar wind circulation and the resultant orientations of polar sand dunes 1983-09 Icarus vol. 55, Sept. 1983, p. 420-431. NASA-supported research. A. W. Ward, K. B. Doyle
K-12 Educational Resources
- Astronomy for Kids
- "The Universe is a place that is vast beyond imagining, and what we will try to do is help you understand a little more about it. There are several sections to the site, but none of them takes a terribly long time to read, and all of them should be easily understood by kids of all ages. Grownups are welcome, too, as long as they promise to behave."
- ASU Mars Education Program
- A good source for materials and other resources for educators.
- ASU Mars Student Imaging Project (MSIP)
- If you are at least a 5th grader, Get Involved with active Mars missions.
- JPL's Mars Education Program
- "Join us on a journey of exploration and discovery as NASA embarks on a 10 year study of the red planet Mars! This site is intended to be useful to students, their teachers, informal education professionals and the general public."
- Mars Exploration: Fun Zone!
- Games and activities for kids of many different ages. Lots of fun, but requires Flash Player (you probably have this).
- Mars Exploration: Mars for Students
- Homework help, Create a colony on Mars, Talk to scientists, Build a Mars spacecraft, See space in detail without a telescope, and much more.
- Space and Science Study Guide
- Astronomy takes a close look at the planets, stars, comets, meteors, and other objects found in outer space.
- Space Today - Exploring Mars
- "A New Era of Red Planet Exploration: What We Know About Mars And How We Know It." A good source of information on both the planet Mars and Mars exploration.
- StarDate-Online: Mars
- "StarDate is the public education and outreach arm of the University of Texas McDonald Observatory. Our English and Spanish radio programs air daily on more than 500 stations. And our popular bimonthly astronomy magazine is the perfect skywatching companion for amateur astronomers or anyone interested in celestial events and space exploration. We also offer astronomy resources to teachers, the media, and the public."