Morphology, mobility and grain size characteristics in new sand dunes (Case study: young Erg of Abshirin)

Document Type : Full length article


Desert Management Department, International Desert Research Center, University of Tehran, Tehran, Iran



The aim of the paper is to assess the morphological characteristics, mobility, and distribution of sediment particle size as maturity indicators of young dunes. The results indicated that according to the Equivalent Sand Thickness (EST) parameter and the wind direction variability parameter, the morphology of the sand dunes was determined as linear. The climatic index of sand dune mobility using meteorological data of Qom, Kashan, and Ardestan synoptic stations in a 27-year period showed that the sand mobility index (M) for sand dunes is 210, which is in the range of fully active dunes. The Grain Size Distribution and the scatterplots diagrams of sorting, skewness, and kurtosis versus the mean size of particles in differentiating the types of sand dunes showed that the relationship of sorting and skewness versus the mean size is effective in showing the dune's mobility. Sediment grain size parameters can be used as an indicator for transport environment and spatial changes. The studies of this research showed that based on grain size characteristics and climatic index, the sand dunes are the simple linear type with full activity. The transport environment in the dune sediments of the upwind sector is more energetic than the dune sediments of the downwind sector
Extended Abstract
Dune fields in arid and semi-arid regions typically form part of local to regional scale sand transport systems, which comprise source areas, transport pathways, and depositional sinks. The range of states of new sand dunes morphology and mobility generally follows the ratio between wind energy for sand transport, aeolian depositions characteristics, and many other environmental factors such as vegetation cover, humidity, and topography. Several parameters have been proposed to account for the morphology and mobility of the sand dunes. Wasson and Hyde considered dune forms as a function of the equivalent sand thickness (EST) parameter and wind direction change (RDP/DP) parameter. The range of states of dune mobility generally follows a climatic gradient. The climatic index of dune mobility developed by Lancaster has been applied to various environments. This index provides a measure of sand mobility (M) as a function of the ratio between the annual percentage of the time the wind is above the threshold for sand transport (W) and the effective annual precipitation (P/PE), where PE is potential evapotranspiration calculated using the Thornthwaite method. The grain size characteristics of the dune sands are closely related to factors such as the dynamic processes of the dunes, sand availability, vegetation, mode and distance of transportation from the source zones, and the energy conditions of the transporting medium. Textural and compositional variables widely used in grain-scale studies are the grain-size parameters (mean size, sorting, skewness, and kurtosis), and the specific gravity mean grain size is widely employed in dynamic interpretations, transport equations and sedimentary environment differentiation. Sorting is very useful in studies of sedimentary environments and aeolian dynamics. Dune sands tend to be better sorted than river sands. Skewness is likewise used to describe grain size distributions in aeolian environments and models to pattern the sediment transport trends. The distinction between the sand types can be numerically stated by computing the distribution curve's skewness (the third moment). On the phi scale, the skewness of dune sands is generally positive, whereas that of beach sands is generally negative. Finally, kurtosis is the less employed grain size parameter, and even Friedman (1961) affirms that it is not an environment-sensitive parameter. An aeolian sedimentary environment dominates the studied area and includes Active depositional dunes that have been formed in the last few decades. This research aims to analyze the characteristics of new sand dunes, including morphology, sediment physics, dunes mobility, and the relationship evaluation between factors to understand the nature of new sand dunes as one of the indicators of dry environments.
The characteristics of new sand dunes were evaluated based on meteorological, remote sensing data, observations, and field sampling. MODIS remote sensing data is used to study the sand dunes' morphology. The meteorological data were derived from two stations of Qom and Kashan. The analysis of the elongation and form of the dunes as the wind direction indicator showed that the area is affected by the winds region of the Qom. The samples were collected from linear sand dunes within varying morphologies. A total of 16 dune sites were studied. Grain size analysis of all samples was carried out using standard dry sieving and sedimentation techniques. Graphic grain-size parameters were estimated following Folk and Ward and using GRADISTAT software. The four size parameters were calculated, namely, mean size, sorting, skewness, and kurtosis. Scatter plot diagrams of mean size versus sorting, skewness, and kurtosis were plotted as scatter diagrams to evaluate their interrelationship and effectiveness in differentiating between the various sand dunes.
Results and Discussion
Anemometry analysis shows that the wind in the region blows from three directions as westerly, north-westerly, and easterly, respectively, based on frequency and speed. Sand-moving winds in the area are strongly controlled from two primary directional sectors, westerly and north-westerly. Total potential sand transport (drift potential, DP) ranges from 202 (Qom station) to 87 (Kashan station) vector units (VU). Different types of sand dunes were identified in Erg Absherin; (a) prebarchanic dunes, (b) wedge-shaped dunes, and (c) simple immaturity linear dunes to silk dunes. The grain size distribution of the samples showed that the sand dunes have an average size range of medium to fine sand. The histograms of the size distribution indicated that they are all unimodal, with a modal class varying between medium to fine sand size. The sands of the studied dunes are poorly sorted; they range in size from 0.46 to 1.12 phi. The young and immature dunes of the northern area are relatively less sorted than the mature dunes. The interrelationship between mean size and skewness shows a general trend of skewness from medium to fine particles. Positivity of skewness increases with the increase in the mean grain size. In the same way, a general decreasing trend is recognized in the interrelationship between mean size and kurtosis, so sediments with a smaller mean size (larger phi) have leptokurtic. The state of dune mobility was determined based on the Lancaster dune mobility index test. The data showed that the sand mobility index (M) for sand dunes is 210, which is in the range of fully active dunes.
The landscape of Kashan deserts is dominated by desert sand dunes, which occupy a considerable area of this region. Many of these new dunes have been formed and developed in the last few decades. Therefore, they provide the form and aeolian deposits with special features. The immaturity of crescent-shaped sand dunes (prebarchanic) to Seif dunes, lack of vegetation cover, and topographical characteristics indicate that the Erg is active. The spatial distribution of sand dunes showed that the linear morphology is consistent with the behavior of Qom station's wind and sand flux patterns. The harmony of the wind and storm rose patterns indicated that both effectively shape the dunes. The value of the dune mobility index exhibits that the dunes are fully active. The Aeolian Sediment Availability was compared with Glaser's diagram. Most of the samples were located in the aeolian mobility sector according to Gläser criteria. In terms of grain size distribution, there are differences in the grain size distributions for different dune types. The dunes are mostly composed of medium to magnificent sands. The sorting parameter indicates that the sands on the southern dunes (downwind) are better sorted than on the northern dunes (upwind). Under the conditions of low wind activity in the south of Erg, the frequency of finer particles and better sorting will increase. In general, the study of the analysis of this new and young Erg indicates that the dunes are characterized by linear or elongated, active, and mobile in an Aoelaian high-energy environment with sands of medium to fine, poorly to moderately well-sorted and finely skewed.
There is no funding support.
Authors’ Contribution
All of the authors approved the content of the manuscript and agreed on all aspects of the work.
Conflict of Interest
Authors declared no conflict of interest.
We are grateful to all the scientific consultants of this paper.


Main Subjects

  1. Afrasinei, G. M., Melis, M. T., Arras, C., Pistis, M., Buttau, C., & Ghiglieri, G. (2018). Spatiotemporal and spectral analysis of sand encroachment dynamics in southern Tunisia. European Journal of Remote Sensing, 51(1), 352-374.
  2. Alcántara-Carrió, J. (1999). Dinámica sedimentaria eólica en el Istmo de Jandía. Modelización y cuantificación del transporte. Unpublished Ph. D. thesis. University of Las Palmas de Gran Canaria, Ed. Cabildo Insular de Gran Canaria, Las Palmas de Gran Canaria.
  3. Alcántara Carrió, J., & Alonso Bilbao, I. (2001). Aeolian sediment availability in coastal areas defined from sedimentary parameters. Application to a case study in Fuerteventura. Scientia Marina.
  4. Arens, S. M., Slings, Q., & De Vries, C. N. (2004). Mobility of a remobilised parabolic dune in Kennemerland, The Netherlands. Geomorphology, 59(1-4), 175-188.
  5. Ash, J. E., & Wasson, R. J. (1983). Vegetation and sand mobility in the Australian desert dunefield. Zeitschrift fur Geomorphologie, 45(Supp.), 7-25.
  6. Ayazi, Z., Mesbahzadeh, T., Ahmadi, H., & Mashhadi, N. (2017). Investigation potential sedimentation geomorphology facies with usage wind erosion meter and IRIFR. E. A model (case study, Kashan-Aran). Desert Management, 4(8), 70-83.  [In Persia].
  7. Bagnold, R.A. (1941). The Physics of Blown Sand and Desert Dunes. Methuen, London. 265 pp.
  8. Bertolini, G., Hartley, A. J., Marques, J. C., & Paim, J. C. (2023). Controls on grain‐size distribution in an ancient sand sea. Sedimentology70(4), 1281-1301.
  9. Besler, H. (1983). The response diagram: distinction between aeolian mobility and stability of sands and aeolian residuals by grain size parameters. Zeitschrift für Geomorphologie. Supplementband45, 287-301.
  10. Blott, S. J., & Pye, K. (2001). GRADISTAT: a grain size distribution and statistics package for the analysis of unconsolidated sediments. Earth surface processes and Landforms26(11), 1237-1248.
  11. Blount, G., & Lancaster, N. (1990). Development of the Gran Desierto sand sea, northwestern Mexico. Geology18(8), 724-728.<0724:DOTGDS>2.3.CO;2
  12. Bullard, J. E., Thomas, D. S. G., Livingstone, I., & Wiggs, G. S. F. (1997). Dunefield activity and interactions with climatic variability in the southwest Kalahari Desert. Earth Surface Processes and Landforms: The Journal of the British Geomorphological Group22(2), 165-174.<165::AID-ESP687>3.0.CO;2-9
  13. Folk, R. L., & Ward, W. C. (1957). Brazos River bar [Texas]; a study in the significance of grain size parameters. Journal of sedimentary research27(1), 3-26.
  14. Friedman, G. M. (1961). Distinction between dune, beach, and river sands from their textural characteristics. Journal of Sedimentary Research31(4), 514-529.
  15. Fryberger, S. G., Dean, G., & McKee, E. D. (1979). Dune forms and wind regime. A study of global sand seas1052, 137-170.
  16. Gaylord, D. R., & Stetler, L. D. (1994). Aeolian-climatic thresholds and sand dunes at the Hanford Site, south-central Washington, USA. Journal of Arid Environments28(2), 95-116.
  17. Gläser, B. (1984). Quantitative untersuchungen zur morphogenese und mobilität des Alt-dünenkomplexes in der Provinz Weiber Nil. Beiträge zur morphodynamik im Relief des Jebel-Marra-Massivs und in seinem Vorland (Darfur/Republik Sudan), 202-217.
  18. Goudie, A., & Viles, H. (2014). Landscapes and landforms of Namibia. Springer.
  19. Hardisty, J., & Whitehouse, R. J. S. (1988). Evidence for a new sand transport process from experiments on Saharan dunes. Nature332(6164), 532-534.
  20. Hasani Darabad, F. Mashhadi, N. (2017). The relationship between Wind-Rose and Storm-Rose with dry and wet periods of normal amberothermic curve (case study: Qom synoptic station). International Conference on Natural Resources Management in Developing Countries. [In Persian].
  21. Hasani Dorabad, F., Mashhadi, N., & Keshtkar, A. (2023). Evaluating the Impacts of Climate fluctuations on wind processes (Case study: Abshirin ecosystem). Journal of Range and Watershed Managment, 76(1), 77-101 Doi:10.22059/JRWM.2023.354591.1693. [In Persian].
  22. Howard, A. D., Morton, J. B., GAD‐EL‐HAK, M. O. H. A. M. E. D., & Pierce, D. B. (1978). Sand transport model of barchan dune equilibrium. Sedimentology25(3), 307-338.
  23. IRIMO. I.R. of Iran Meteorological Organization. Meteorological Organization Report.
  24. Kasper-Zubillaga, J. J., & Carranza-Edwards, A. (2005). Grain size discrimination between sands of desert and coastal dunes from northwestern Mexico. Revista Mexicana de Ciencias Geológicas22(3), 383-390.
  25. Khalaf, F. (1989). Textural characteristics and genesis of the aeolian sediments in the Kuwaiti desert. Sedimentology36(2), 253-271.
  26. Klintenberg, P., & Seely, M. (2004). Land degradation monitoring in Namibia: A first approximation. Environmental Monitoring and Assessment99, 5-21.
  27. Kocurek, G., & Ewing, R. C. (2005). Aeolian dune field self-organization–implications for the formation of simple versus complex dune-field patterns. Geomorphology72(1-4), 94-105.
  28. Lancaster, N. (1988). Development of linear dunes in the southwestern Kalahari, southern Africa. Journal of arid environments14(3), 233-244.
  29. Lancaster, N., & Tchakerian, V. P. (1996). Geomorphology and sediments of sand ramps in the Mojave Desert. Geomorphology17(1-3), 151-165.
  30. Lancaster, N., & Helm, P. (2000). A test of a climatic index of dune mobility using measurements from the southwestern United States. Earth Surface Processes and Landforms: The Journal of the British Geomorphological Research Group25(2), 197-207.<197::AID-ESP82>3.0.CO;2-H
  31. Lancaster, N. (2005). Aeolian erosion, transport and deposition, in Selley, R.C., Robin, L., Cocks, M., and Plimer, I.R., eds., Encyclopedia of Geology. Oxford, Elsevier, p. 612–627.
  32. Lancaster N. (2009). Aeolian features and processes, In: Young R, Norby L (eds) Geological Monitoring: Boulder, Colorado.Geological Society of America: 1–25.
  33. Lancaster, N., Baker, S., Bacon, S., & McCarley-Holder, G. (2015). Owens Lake dune fields: composition, sources of sand, and transport pathways. Catena134, 41-49.
  34. Le Roux, J. P. (1994). A spreadsheet template for determining sediment transport vectors from grain-size parameters. Computers & Geosciences20(3), 433-440.
  35. Liu, S., & Wang, T. (2014). Aeolian processes and landscape change under human disturbances on the Sonid grassland of inner Mongolian Plateau, northern China. Environmental earth sciences71, 2399-2407.
  36. Lopez, O. M., Hegy, M. C., & Missimer, T. M. (2020). Statistical comparisons of grain size characteristics, hydraulic conductivity, and porosity of barchan desert dunes to coastal dunes. Aeolian research43, 100576.
  37. Mainguet, M. (1986). The wind and desertification processes in the Saharo-Sahelian and Sahelian regions. In Physics of desertification (pp. 210-240). Dordrecht: Springer Netherlands.
  38. Mashhadi, N., AHMADI, H., Ekhtesasi, M. R., FEYZNIA, S., & Feghhi, G. (2007). Analysis of sand dunes to determine wind direction and detect sand source sites (case study: Khartooran Erg, Iran).
  39. Mashhadi, N., Feiznia, S., & Abdi, S. (2019). Dynamic and Genetic Analysis of Aeolian Sedimentation to Determine Origin and Source of Sand Dunes (Case Study: Reza Abad, Sabzevar). Physical Geography Research Quarterly51(3), 389-402. Doi: 10.22059/JPHGR.2019.254097.1007190 [In Persia].
  40. Mashhadi, N. 2022. The effect of the aeolian process on the natural environment of the desert (Case study: New Erg of Ab shirin), The 4th National Conference on Environmental Engineering and Management. [In Persia].
  41. Muhs, D. R., & Maat, P. B. (1993). The potential response of eolian sands to greenhouse warming and precipitation reduction on the Great Plains of the USA. Journal of Arid Environments25(4), 351-361.
  42. Muhs, D. R., & Holliday, V. T. (1995). Evidence of active dune sand on the Great Plains in the 19th century from accounts of early explorers. Quaternary Research43(2), 198-208.
  43. Muhs, D. R., Reynolds, R. L., Been, J., & Skipp, G. (2003). Eolian sand transport pathways in the southwestern United States: importance of the Colorado River and local sources. Quaternary International104(1), 3-18.
  44. Muhs, D. R. (2004). Mineralogical maturity in dunefields of North America, Africa and Australia. Geomorphology59(1-4), 247-269.
  45. Okin, G. S., & Gillette, D. A. (2001). Distribution of vegetation in wind‐dominated landscapes: Implications for wind erosion modeling and landscape processes. Journal of Geophysical Research: Atmospheres106(D9), 9673-9683.
  46. Parteli, E. J., Durán, O., Bourke, M. C., Tsoar, H., Pöschel, T., & Herrmann, H. (2014). Origins of barchan dune asymmetry: Insights from numerical simulations. Aeolian Research12, 121-133.
  47. Pye, K., & Tsoar, H. (2008). Aeolian Sand and Sand Dunes. Springer Science & Business Media.
  48. Rahi, G., Bahreini, F., & Khosroshahi, M. (2022). Monitoring and Predicting the Effect of Climatic Factors on Sand-Mobility Using Lancaster Index: A Case Study of Dayer, Bushehr Province. Desert Ecosystem Engineering11(36), 41-54. Doi:10.22052/DEEJ.2021.11.36.41. [In Persia].
  49. Rout, U. (2018). Geochemical, Textural and Mineralogical Analysis Of Aeolian Sediments.
  50. Sherman, D. J., & Hotta, S. H. I. N. T. A. R. O. (1990). Aeolian sediment transport: theory and measurement. Coastal Dunes: form and process17, 37.
  51. Stetler, L. D., & Gaylord, D. R. (1996). Evaluating eolian-climatic interactions using a regional climate model from Hanford, Washington (USA). Geomorphology17(1-3), 99-113.
  52. Syvitski, J. P., & Kettner, A. (2011). Sediment flux and the Anthropocene. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences369(1938), 957-975.
  53. Talbot, M. R. (1981). Environmental responses to climatic change in the West African Sahel over the past 20,000 years.
  54. Tavakolifard, A., Ghasemiye, H., Nazari Samani, A. A., Mashhadi, N., & Mirzavand, M. (2012). Investigation of role of different land uses in the sand storm by using wind rose and storm rose (Case study, Kashan). Environ. Erosion Res. J2(2), 25-41. [In Persian].
  55. Tavakkolifard, A., Ghasemieh, H., Samani, A. A. N., & Mashhadi, N. (2013). Determining the risk of sand transportation to residential areas around Kashan Erg using anemometry data analysis.
  56. Tavakolifard, A., Ghasemiye, H., Nazari Samani, A. A. & Mashhadi, N. (2015). 'Investigation morphology and sand dunes activity in different parts based on Lancaster index (Case stydy: Kashan Erg). Desert Ecosystem Engineering, 3(5), pp. 37-48. [In Persia].
  57. Tchakerian, V. P. (1991). Late Quaternary aeolian geomorphology of the Dale Lake sand sheet, southern Mojave Desert, California. Physical Geography12(4), 347-369.
  58. Thomas, D. S. G., & Tsoar, H. (1990). The geomorphological role of vegetation in desert dune systems. Vegetation and erosion, 471-489.
  59. Wasson, R. J., & Hyde, R. (1983). Factors determining desert dune type. Nature304(5924), 337-339.
  60. Wasson, R. J. (1984). Late Quaternary palaeoenvironments in the desert dunefields of Australia. In Late Cainozic palaeoclimates of the Southern Hemisphere. International symposium held by the South African Society for Quaternary Research; Swaziland (pp. 419-432).
  61. Wang, X., Dong, Z., Zhang, J., & Chen, G. (2002). Geomorphology of sand dunes in the Northeast Taklimakan Desert. Geomorphology42(3-4), 183-195.
  62. Wang, X., Dong, Z., Zhang, J., Qu, J., & Zhao, A. (2003). Grain size characteristics of dune sands in the central Taklimakan Sand Sea. Sedimentary Geology161(1-2), 1-14.
  63. Wolfe, S. A. (1997). Impact of increased aridity on sand dune activity in the Canadian Prairies. Journal of Arid Environments36(3), 421-432.
  64. Yousefi, M. E., Ghodrati, M., & Khosroshahi, M. (2021). Monitoring and Forecasting of Effective Climatic Factors on the Mobility of Sand Dunes in Semnan province. [In Persia].
  65. Zandifar, S., Khosroshahi, M., Ebrahimikhusfi, Z., & Naeimi, M. (2021). Using Lancaster Index to Analyse of the Sand Dunes Activity in Arid lands and Sensitivity Analysis of the Factors Affecting it (Case Study: Buin-Zahra City). Desert Management8(16), 1-16. Doi 10.22034/JDMAL.2021.243137. [In Persia].
  66. Zhang, H., Fan, J., Cao, W., Harris, W., Li, Y., Chi, W., & Wang, S. (2018). Response of wind erosion dynamics to climate change and human activity in Inner Mongolia, China during 1990 to 2015. Science of the Total Environment639, 1038-1050.
  67. Zhang, X. Y., Gong, S. L., Zhao, T. L., Arimoto, R., Wang, Y. Q., & Zhou, Z. J. (2003). Sources of Asian dust and role of climate change versus desertification in Asian dust emission. Geophysical Research Letters30(24).
  68. Zhang, Z., & Dong, Z. (2015). Grain size characteristics in the Hexi Corridor Desert. Aeolian Research18, 55-67.
  69. Zhao, C., Zhang, H., Wang, M., Jiang, H., Peng, J., & Wang, Y. (2021). Impacts of climate change on wind erosion in Southern Africa between 1991 and 2015. Land Degradation & Development32(6), 2169-2182.
  70. Zhao, Y., Wu, J., He, C., & Ding, G. (2017). Linking wind erosion to ecosystem services in drylands: a landscape ecological approach. Landscape Ecology32, 2399-2417.