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| Grain size distribution at four developmental stages of crescent dunes in the hinterland of the Taklimakan Desert, China |
| JIA Wenru1, ZHANG Chunlai1*, LI Shengyu2, WANG Haifeng2, MA Xuexi2,3, WANG Ningbo2 |
1 State Key Laboratory of Earth Surface Processes and Resource Ecology, Ministry of Education Engineering Center of Desertification and Blown-sand Control, Beijing Normal University, Beijing 100875, China;
2 Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China;
3 Xinjiang Academy of Forestry Science, Urumqi 830046, China |
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Abstract Although scientists have performed many studies on crescent (barchan) dunes in the Taklimakan Desert, few studies reported the changes in grain size at different development stages of crescent dunes. In order to evaluate the changing trends of surface sediment grain size with dune development, we investigated the grain size characteristics at four developmental stages (oval sand pile, shield dune, incipient crescent dune and mature crescent dune) of crescent dunes by measuring the morphology of sand dune and observing the near-surface wind regime. The dunes have developed in a wide inter-dune corridor between high compound longitudinal ridges in China’s Taklimakan Desert. The surface sediments at four developmental stages of the crescent dunes were primarily composed of fine sands, followed by very fine and medium sands. Mean grain sizes ranged from 2.8 to 3.1 φ, with a unimodal distribution. The sands were moderately well-sorted, their distribution varied from platykurtic to very platykurtic, and symmetrical or skewed towards the fine particles. From oval sand piles through shield and incipient crescent dunes to mature crescent dunes, incipient grain size gradually increased, particles became finer, sorting became better, kurtosis and skewness increased. Grain sizes on the surface layer became coarser upwards from the toe of the windward slope and then became finer towards the bottom of the leeward slope. We found that the coarsest particles at different positions at the four developmental stages were different. The coarsest particles were distributed at the top of the oval sand piles and shield dunes, versus at the middle of the windward slope of the incipient and mature crescent dunes. Correlations between the mean grain size and other grain size parameters showed that as mean grain size became finer, sorting became better and kurtosis became wider, but skewness changed only slightly. In addition, grain size variation in the surface sediments correlated with the movement speed of the dunes in the study area. In the open ground among tall-complex longitudinal ridges in the hinterland of the Taklimakan Desert where aeolian environment is characterized by comparatively strong wind and unsaturated sand flow, faster dune movement corresponded to coarser grain size.
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Received: 26 December 2015
Published: 15 June 2016
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| Fund: This research was supported by the National Natural Science Foundation of China (41571011, 41330746). |
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Corresponding Authors:
ZHANG Chunlai
E-mail: clzhang@bnu.edu.cn
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| Anderson R S, Haff P K. 1988. Simulation of Eolian saltation. Science, 241(4867): 820–823. Bagnold R A. 1941. The Physics of Blown Sand and Desert Dune. London: Methuen, 85–96. Ding G D. 2010. Aeolian Physics (2nd ed.). Beijing: China Forestry Publishing House, 105–110. (in Chinese) Folk R L, Ward W C. 1957. Brazos river bar: a study in the significance of grain size parameters. Journal of Sedimentary Petrology, 27(1): 3–26. Ha S, Wang G Y, Dong G R. 2001. Lee-face airflow, depositional types and its significance. Acta Sedimentologica Sinica, 19(1): 96–100. (in Chinese)Hesp P A, Hastings K. 1998. Width, height and slope relationships and aerodynamic maintenance of barchans. Geomorphology, 22(2): 193–204. Ji Q H. 1996. Application of grain size analysis in the studies of Taklimakan Desert. Journal of Desert Research, 16(2): 173–179. (in Chinese)Lancaster N. 1985. Variations in wind velocity and sand transport on the windward flanks of desert sand dunes. Sedimentology, 32(4): 581–593. Lancaster N. 1989. The Namib Sand Sea: Dune Forms, Processes and Sediments. Rotterdam: Balkema, 192. Lancaster N. 1995. Geomorphology of Desert Dunes. New York: Routledge. Lancaster N, Nickling W G, Neuman C M. 2002. Particle size and sorting characteristics of sand in transport on the stoss slope of a small reversing dune. Geomorphology, 43(3–4): 233–242. Ling Y Q, Wu Z, Liu S Z, et al. 1998. Simulated study on barchan dune forms. Scientia Geographica Sinica, 18(1): 88–93. (in Chinese)Liu X W, Li S, Shen J Y. 1999. Wind tunnel simulation experiment of mountain dunes. Journal of Arid Environments, 42(1): 49–59. Livingstone I. 1989. Temporal trends in grain-size measures on a linear sand dune. Sedimentology, 36(6): 1017–1022. Livingstone I. 2013. Aeolian geomorphology of the Namib Sand Sea. Journal of Arid Environments, 93: 30–39. Nickling W G, Neuman C M, Lancaster N. 2002. Grainfall processes in the lee of transverse dunes, Silver Peak, Nevada. Sedimentology, 49(1): 191–209. Pye K, Tsoar H. 1990. Aeolian Sand and Sand Dunes. London: Unwin Hyman, 396. Schatz V, Herrmann H J. 2006. Flow separation in the lee side of transverse dunes: a numerical investigation. Geomorphology, 81(1–2): 207–216. Shanbei Department, Chengdu Institute of Geology. 1978. Grain Size Analysis of Sediments (Rocks) and Its Application. Beijing: Geology Press, 55–133. (in Chinese) Tsoar H. 2006. Dynamic processes acting on a longitudinal (seif) sand dune. Sedimentology, 30(4): 567–578. Vincent P J. 1984. Particle size variation over a transverse dune in the Nafud as Sirr, central Saudi Arabia. Journal of Arid Environments, 7(4): 329–336. Wang X M, Dong Z B, Zhang J W, et al. 2002. Relations between morphology, air flow, sand flux and particle size on transverse dunes, Taklimakan Sand Sea, China. Earth Surface Processes and Landforms, 27(5): 515–526. Wang X M, Dong Z B, Zhang J W, et al. 2003. Grain size characteristics of dune sands in the central Taklimakan Sand Sea. Sedimentary Geology, 161(1–2): 1–14. Watson A. 1986. Grain-size variations on a longitudinal dune and a barchan dune. Sedimentary Geology, 46(1–2): 49–66. White B R, Tsoar H. 1998. Slope effect on saltation over a climbing sand dune. Geomorphology, 22(2): 159–180. Wu Z. 2003. Geomorphology of Wind-drift Sands and Their Controlled Engineering. Beijing: Science Press, 165–170. (in Chinese)Zhang C L, Hao Q Z, Zou X Y, et al. 1999. Response of morphology and deposits to surface flow on windward slope of barchan dune. Journal of Desert Research, 19(4): 359–363. (in Chinese)Zhu Z D, Chen Z P, Wu Z. 1981. Study on Aeolian landform in Taklimakan Desert. Beijing: Science Press. (in Chinese)Zu R P, Zhang K C, Qu J J, et al. 2005. The intensity of sand-drift activities in Taklimakan Desert. Geographical Research, 24(5): 699–707. (in Chinese) |
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