Grain size characteristics in the Hexi Corridor Desert

Zhang, Zhengcai; Dong, Zhibao

doi:10.1016/j.aeolia.2015.05.006

Cited by 59 publications

(62 citation statements)

References 25 publications

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“…The mean grain size was the smallest for the lacustrine sediment and gravel under layer (0.08 and 0.11 mm, respectively) and larger for the dune surface (0.25 to 0.47 mm). The mean grain size for all of the sand dune surfaces decreased from upwind (SD2 is 0.47 mm) to downwind (SD3 is 0.30 mm), which was a similar behavior as in the observations by Zhang and Dong [35]. In dune SD3, the mean grain size was smaller on the windward slope than on the two limbs (0.30 mm on the windward slope (SD3T-a); 0.39 mm at SD3T-b; 0.42 and 0.35 at SD3T-c and SD3T-d, respectively).…”

Section: Grain Size Parameterssupporting

confidence: 86%

“…There were 13% that was platykurtic, and 87% were mesokurtic. In a study that was performed approximately 60 km downwind of our study area, Zhang and Dong [35] reported that the sand was mainly moderately sorted (46%) and well sorted (29%), the skewness is mainly symmetrical (40%) and negative (27%), and the kurtosis is mainly mesokurtic (37%) and platykurtic (29%). Based on the findings from the study area and those of [15], the sorting increased, the skewness graded toward symmetrical, and the kurtosis graded toward mesokurtic, with an increasing distance downwind that was consistent with the conclusions that were developed by Zhang et al [15] from a study that was performed in the Hexi Corridor Desert.…”

Section: Grain Size Parametersmentioning

confidence: 92%

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Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China

Zhang

Dong

et al. 2018

Geosciences

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Crescent-shaped barchan dunes often display an asymmetric shape, with one limb longer than the other. As shown in previous studies, asymmetric bimodal winds constitute one major cause of barchan asymmetry, but the heterogeneous conditions of sand availability or flux, as well as topographic influences, may be also important. Understanding the morphology and dynamics of asymmetric barchans may have an impact in a broad range of areas, particularly as these dunes may serve as a proxy for planetary wind regimes and soil conditions in extraterrestrial environments. However, in addition to the existing theories and numerical models that explain barchan asymmetry, direct measurements of migration rates and morphologic changes of real asymmetric barchans over a time span of several years would be beneficial. Therefore, here we report such measurements, which we have acquired by investigating asymmetric barchans in the Hexi Corridor, northwest of China. We have found that dune interactions and asymmetric influx conditions are the most important causes of barchan asymmetry in this field. Particle size distributions in the Hexi Corridor display strong variations over different parts of the asymmetric barchans, as well as over different dunes, with gravel particles being incorporated from the substrate as the dunes migrate. Our observations have shown that upwind sediment sources are important for dune formation in the Hexi Corridor, and that interdune interactions affect dune shape in different ways, depending on their offset. The asymmetric barchans in the Hexi Corridor are active, with an average migration rate (MR) between 8 and 53 m year −1 , in spite of the different asymmetric shapes. Our data for dune migration rates can be described well by a scaling of MR = A/(W + W0), where W is the barchan cross-wind width, A ≈ 2835 m 2 s −1 , and W0 ≈ 44 m. A similar scaling fits very well the migration rate as a function of dune along-wind width L, (i.e., MR = B/(L + L0), with B ≈ 1722 m 2 s −1 and L0 ≈ 13 m). Linear relations are also found between both dune widths and the average limb and windward side lengths, thus indicating that the morphometric relations that are predicted from models for steady-state, symmetric crescent-shaped dunes can be applied to different transitional morphologies of interacting, asymmetric barchans.

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Section: Grain Size Parameterssupporting

confidence: 86%

Section: Grain Size Parametersmentioning

confidence: 92%

Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China

Zhang

Dong

et al. 2018

Geosciences

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“…Grain size parameter, such as mean grain size and content of different sand grain size category controlled sand entrainment, transport distance, and so on. Mean grain size decreased with sand transport distance (Dong et al, ; Mischke, ; Qian et al, ; Zhang & Dong, ). Table shows the content of grain size category for barchan dunes, linear dunes, raked dunes, and transported sand.…”

Section: Resultsmentioning

confidence: 99%

Formation and development of dunes in the northern Qarhan Desert, central Qaidam Basin, China

et al. 2017

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The Qarhan Desert in the Qaidam Basin is a high‐elevation geomorphic depression characterized by low temperatures, resulting in an environment similar to those predicted to exist on Mars. As a result, this desert has attracted many aeolian researchers. However, relatively little research has addressed the factors that control dune formation in this region. In this paper, we used observational wind data and sediment characteristics to analyze the formation and development of 3 dune types. The spatial distribution of the Qarhan Desert dune types is controlled by both wind regime and surface characteristics (primarily surface barriers, i.e., yardangs). Linear dunes formed on the leeside of yardangs and became elongated under a bimodal wind regime. The elongation direction of the linear dunes (295°) was similar to the direction of potential sand transport (290° to 296°). Linear dune development experienced different erosion and deposition processes under different climate regimes, and the dunes can be divided into developed and developing linear dunes at present. The movement of developed linear dunes included elongation and lateral movement; however, the movement of developing linear dunes was restricted to elongation. The mean elongation movement rate of the developing and developed linear dunes was approximately 16.87 and 4.84 m/yr, respectively.

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“…3), their origin indicates an accumulation on a dry substrate (Mountney, 2012) by migrating wind ripples (Hunter, 1977;Rodríguez-López et al, 2008). By applying grain size parameters it is possible to diagnose particular sedimentary environments as the strength of the transporting environment (Mz), the changeability and dynamics of transport (σ) and the variation in the strength of the transporting environment (Folk, 1971;Folk & Ward, 1957;Visher, 1969;Zhang & Dong, 2015). In an aeolian environment, sediment grain size distribution controls creep, saltation and suspension in landform (dune) formation and development (Zhang & Dong, 2015).…”

Section: What Does the Aeolian-glaciolacustrine Contact Look Like?mentioning

confidence: 99%

“…By applying grain size parameters it is possible to diagnose particular sedimentary environments as the strength of the transporting environment (Mz), the changeability and dynamics of transport (σ) and the variation in the strength of the transporting environment (Folk, 1971;Folk & Ward, 1957;Visher, 1969;Zhang & Dong, 2015). In an aeolian environment, sediment grain size distribution controls creep, saltation and suspension in landform (dune) formation and development (Zhang & Dong, 2015). Since medium-and fine-grained and moderately sorted sands prevail at the site investigated, and the range of these values is rather narrow with a single-segmented cumulative curves (Fig.…”

Section: What Does the Aeolian-glaciolacustrine Contact Look Like?mentioning

confidence: 99%

An aeolian or a glaciolacustrine record? A case study from Mieļupīte, Middle Gauja Lowland, northeast Latvia

Nartišs

Kalińska

2017

Geologos

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In the Middle Gauja Lowland, northeast Latvia, dunes are distributed over a vast glaciolacustrine plain that formed during the retreat of the Fennoscandian ice sheet. Such a direct contact between aeolian and glaciolacustrine sediments can be used to infer depositional settings and decipher to what extent these sediments bear an aeolian component. Our proxies, although preliminary, reveal a limited range of variation in grain-size parameters, a significant presence of quartz grains with silica precipitation and matt-surface grains of various rounding degrees and massive structure combined with horizontal lamination. These are indicative of periglacial-aeolian depositional conditions in the foreland of the Linkuva ice-marginal zone. Sedimentary characteristics do not match a single luminescence date of 9.2±0.6 ka, which significantly postdates the minimum age of the Linkuva ice-marginal zone with 10Be ages between 15.4 and 12.0 ka. Whether deposition started directly after drainage of the Middle Gauja ice-dammed lake or if there is a gap of 2.8-6.2 ka is a matter of debate; only future studies at higher OSL resolution could resolve this.

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Grain size characteristics in the Hexi Corridor Desert

Cited by 59 publications

References 25 publications

Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China

Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China

Formation and development of dunes in the northern Qarhan Desert, central Qaidam Basin, China

An aeolian or a glaciolacustrine record? A case study from Mieļupīte, Middle Gauja Lowland, northeast Latvia

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