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1.
Sedimentary architecture and genesis of residual dune ridges in a temperate climate are presented and implications for their use as archive of changes in long-term precipitation and wind climate are discussed. Residual dunes are common features of wet aeolian systems, where they form sets of shallow ridges, oriented perpendicular to the prevailing wind direction. Residual dune ridges of the study area are vegetated and typically elevate 0.6 to 2.5 m above the surrounding interdune flats. They develop on the lower stoss side of active transgressive dunes, triggered by periods of elevated groundwater table and hence colonization of the foot of the dune by rapid growing pioneer vegetation. Stabilized by plants, the growing ridge detaches from the active transgressive dune and gets abandoned within years in the course of the downwind-migration of the transgressive dune. Grain-size data suggest a main sediment supply from the transgressive dune and only minor input from other sources. Ground-penetrating radar reveals that the residual dune ridges are composed of windward-dipping as well as leeward-dipping sedimentary beds. Leeward-dipping strata reflect sediment supply from the parental dune, whereas windward-dipping beds are seen to result from sediment redistribution along the ridge and sediment supply from the adjacent swales during the ridge growth period. Multi-annual to multi-decadal variability in precipitation leads to the development of sequences composed of tens of ridges, spanning time periods of several centuries. Spacing of individual ridges in these sequences is controlled not by long-term variability in precipitation alone, but probably also reflects variable wind intensity which affects the migration rate of the parental dune. The important role of vegetation in ridge construction makes these landforms a demonstrative example of landscape development by geo-biosphere interacting processes.  相似文献   

2.
The evolution of the shore-normal profile shape of accreting tidal flats is controlled mainly by tidally induced mud and sand transport. To understand the evolution processes, a model is developed to simulate the tidal flat profile changes in response to spring-neap tidal cycles. The model treats both sand and mud transport patterns over the tidal flats and adopts an algorithm to deal with the areas near the high water (HW) level on springs. The model is applied to an accreting tidal flat on the central Jiangsu coast, to investigate the relationship between the equilibrium profile shape of the tidal flat and the various influencing factors (e.g. initial profile shape of tidal flat, tidal range and sediment supply). Based on the modeling results the following conclusions are derived: (1) the accreting tidal flat tends to be convex in profile shape when it reaches an equilibrium state; (2) sediment supply is a key factor affecting the width and accretion-erosion status of the tidal flat; (3) filling the area close to high water (HW) on spring tides is essential for reproducing the shape evolution and the morphodynamic behavior of tidal flats; (4) after an equilibrium shape is formed, a tidal flat with abundant sediment supply can steadily prograde to seaward, at the same time maintaining the equilibrium shape; and (5) the modeled width and the slope of the tidal flat are consistent with those of the central Jiangsu coast when the parameters adopted in the model are appropriate for the local conditions.  相似文献   

3.
With both sides of the Taklimakan Desert highway line as the study area, three typical aeolian sand landforms, i.e. complex dune ridge, barchan dune and flat sand land, were selected as sand beds for the observation, analysis and research of the characteristics of aeolian sand movement such as aeolian sand stream structure, sand transport intensity, etc. in the Taklimakan Desert. The results show that there is a linear relation between the height and the log of sand transport rate over transverse dune chain, longitudinal dune ridge and flat sand land, i.e. the sand transport percentage decreases exponentially with increasing height. Sand transport rate within the 10 cm height above the bed surface accounts for 80%-95% of the total sand transport rate of the observed height (40 cm), while the sand transport rate in 20 cm occupies 98% of the total amount. Sand transport rate (g·cm-1·min-1) differs greatly with respect to different landform types and different topographic positions. Based on the investig  相似文献   

4.
Within the greater Ar Rub' al Khali (Empty Quarter) sand sea lies an internal depocentre, the Al Liwa Basin, which comprises a variety of mega‐scale dune types. Crescentic dunes dominant the north of the basin while megadunes of stellate or star form are a major landform of the south‐eastern reaches. Their development into dune fields is determined by the style and rate of dune–dune interactions, the boundary conditions imposed by a multi‐modal wind regime, fluctuating groundwater levels, and sediment availability under an assortment of climatic conditions throughout the Quaternary. As a result, dune field patterns are a collective response to these perturbations in space, time and environment. The R‐statistic is a collective measure of these responses, and is a metric capable of identifying the degree of pattern maturity or self‐organization of the aeolian system, and the pathways from which patterns evolve. The spatial signature of the southerly located star dunes is characterized by two definitive patterns of organization: the first, one of complete spatial randomness, the second, a low degree of spatial uniformity. In isolation, these results appear to be unrelated to those for crescentic dunes of the region in which a significantly higher degree of pattern dispersion is the norm. However, when spatial statistical measures are integrated with the theoretical understanding of dune–dune interactions and the involvement of environmental agents, the complex morphodynamic pathways and linkages between regional dune fields is better understood. In this case, both constructive (e.g. merging, lateral linking) and regenerative activity (e.g. calving) have played important roles in the development of dune size, and associated adjustments in spacing, and dune numbers, and subsequently dune field patterns. Synergetic patterns are emblematic of this vast dunescape, whereby transitional geographic, morphologic, dimensional and environmental modifications exist between the mega‐crescentic and mega‐stellate dunes of the Empty Quarter. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

5.
On June 29, 2009, version 1 of the ASTER GDEM (Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model) was made available at no cost or restrictions to users worldwide via electronic download. The ASTER GDEM provides expanded spatial coverage and better resolution than other global digital elevation models (DEMs). In this paper we demonstrate how the ASTER GDEM provides new opportunities for investigating large aeolian sand dunes in three‐dimensions. Two dune‐specific spatial analysis methods are presented to illustrate potential applications of these data for discriminating dune generations and quantifying spatial variations of sediment supply. Moreover, we review how existing and emerging fields of dune pattern analysis and simulation modeling will be able to make significant advances through application of these data, potentially leading to future progress in studies of dune morphodynamics, environmental controls, and paleoenvironmental reconstructions. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

6.
Wind characteristics and aeolian transport were measured on a naturally evolving beach and dune and a nearby site where the beach is raked and sand‐trapping fences are deployed. The beaches were composed of moderately well sorted to very well sorted fine to medium sand. The backshore at the raked site was wider and the foredune was more densely vegetated and about 1 m higher than at the unraked site. Wind speeds were monitored using anemometers placed at 1 m elevation and sand transport was monitored using vertical traps during oblique onshore, alongshore and offshore winds occurring in March and April 2009. Inundation of the low backshore through isolated swash channels prevented formation of a continuously decreasing cross‐shore moisture gradient. The surface of the berm crest was dryer than the backshore, making the berm crest the greatest source of offshore losses during offshore winds. The lack of storm wrack on the raked beach reduced the potential for sediment accumulation seaward of the dune crest during onshore winds, and the higher dune crest reduced wind speeds and sediment transport from the dune to the backshore during offshore winds. Accretion at wrack seaward of the dune toe on the unraked beach resulted in a wider dune field and higher, narrower backshore. Although fresh wrack is an effective local trap for aeolian transport, wrack that becomes buried appears to have little effect as a barrier and can supply dry sand for subsequent transport. Aeolian transport rates were greater on the narrower but dryer backshore of the unraked site. Vegetation growth may be necessary to trap sand within zones of buried wrack in order to allow new incipient foredunes to evolve. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

7.
Ephemeral aeolian sand strips are commonplace on beaches. Their formation during high energy sand transport events often precedes the development of protodunes and their dynamics present interesting feedback mechanisms with surface moisture patterns. However, due to their temporary nature, little is known of their formation, mobility or the specifics of their interaction with beach surface characteristics. Similarly surface moisture has an important influence on sediment availability and transport in aeolian beach systems, yet it is difficult to quantify accurately due to its inherent variability over both short spatial and temporal scales. Whilst soil moisture probes and remote sensing imagery techniques can quantify large changes well, their resolution over mainly dry sand, close to the aeolian transport threshold is not ideal, particularly where moisture gradients close to the surface are large. In this study we employed a terrestrial laser scanner to monitor beach surface moisture variability during a three and a half hour period after a rain event and investigated relationships between bedform development, surface roughness and surface moisture. Our results demonstrate that as the beach surface dries, sand transport increases, with sediment erosion occurring at the wet/dry surface boundary, and deposition further downwind. This dynamic structure, dependent upon changing surface moisture characteristics, results in the formation of a rippled sand strip and ultimately a protodune. Our findings highlight dynamic mobility relationships and confirm the need to consider transient bedforms and surface moisture across a variety of scales when measuring aeolian transport in beach settings. The terrestrial laser scanner provides a suitable apparatus with which to accomplish this. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

8.
Changes in wind speed and sediment transport are evaluated at a gap and adjacent crest of a 2 to 3 m high, 40 m wide foredune built by sand fences and vegetation plantings on a wide, nourished fine sand beach at Ocean City, New Jersey. Anemometer masts, cylindrical sand traps and erosion pins were placed on the beach and dune during two obliquely onshore wind events in February and March 2003. Results reveal that: (1) changes in the alongshore continuity of the beach and dune system can act as boundaries to aeolian transport when winds blow at an angle to the shoreline; (2) oblique winds blowing across poorly vegetated patches in the dune increase the potential for creating an irregular crest elevation; (3) transport rates and deflation rates can be greater within the foredune than on the beach, if the dune surface is poorly vegetated and the beach has not had time to dry following tidal inundation; (4) frozen ground does not prevent surface deflation; and (5) remnant sand fences and fresh storm wrack have great local but temporary effect on transport rates. Temporal and spatial differences due to sand fences and wrack, changes in sediment availability due to time‐dependent differences in surface moisture and frozen ground, combined with complex topography and patchy vegetation make it difficult to specify cause–effect relationships. Effects of individual roughness elements on the beach and dune on wind flow and sediment transport can be quantified at specific locations at the event scale, but extrapolation of each event to longer temporal and spatial scales remains qualitative. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

9.
Farewell Spit is a 25 km long barrier spit that marks the end of a littoral drift system, almost 1000 km in length that runs along South Island, New Zealand. The spit is composed of barchan dunes over 20 m high, sand sheets over 1 km wide and vegetated linear dunes. Analysis of aerial photography indicates a rapid colonization of the spit by vegetation which has expanded in area by 75% since 1950. Vegetation colonization preferentially occurs on the southern side of the spit, with its northern margin characterized by barchan dunes which migrate at rates of up to 64 m/yr. Sand sourced from longshore drift appears to be the primary source of beach sediment, which is then transported into the dune field by the persistent westerly winds of the Roaring 40s. While there has been significant dune roll‐over on the surface of the spit, its overall area has remained much the same for the past 54 years. Occasional cyclone events cause erosion, but this is balanced by aeolian sediment transport. It would appear that extension of the subaerial portion of the spit is related to the development of shells banks at its downdrift end which are periodically welded to the main spit by dune extension. Farewell Spit therefore provides an ideal example of a barrier environment where longshore sediment supply and aeolian transport dominates geomorphic evolution. This differentiates the study site from other barrier environments where overwash or tidal inlet development often characterizes recent landform evolution. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

10.
Analyses of shoreline and bathymetry change near Calais, northern coast of France, showed that shoreline evolution during the 20th century was strongly related with shoreface and nearshore bathymetry variations. Coastal erosion generally corresponds to areas of nearshore seabed lowering while shoreline progradation is essentially associated with areas of seafloor aggradation, notably east of Calais where an extensive sand flat experienced seaward shoreline displacement up to more than 300 m between 1949 and 2000. Mapping of bathymetry changes since 1911 revealed that significant variation in nearshore morphology was caused by the onshore and alongshore migration of a prominent tidal sand bank that eventually welded to the shore. Comparison of bathymetry data showed that the volume of the bank increased by about 10×107 m3 during the 20th century, indicating that the bank was acting as a sediment sink for some of the sand transiting alongshore in the coastal zone. Several lines of evidence show that the bank also represented a major sediment source for the prograding tidal flat, supplying significant amounts of sand to the accreting upper beach. Simulation of wave propagation using the SWAN wave model (Booij et al., 1999) suggests that the onshore movement of the sand bank resulted in a decrease of wave energy in the nearshore zone, leading to more dissipative conditions. Such conditions would have increased nearshore sediment supply, favoring aeolian dune development on the upper beach and shoreline progradation. Our results suggest that the onshore migration of nearshore sand banks may represent one of the most important, and possibly the primary mechanism responsible for supplying marine sand to beaches and coastal dunes in this macrotidal coastal environment.  相似文献   

11.
Sediment budget data from an 18‐month topographic survey were analysed with data from brief experiments on wind parameters, beach moisture contents, bedforms and sand mobilization in order to monitor conditions and patterns of embryo dune development over a flat 150–1000 m wide accreting upper beach. The surface conditions over the upper beach locally affect aeolian transport, but net dune development over time depends on sustained strong winds and their orientation. Incoming marine sand supplied by storms and onshore winds is reorganized by the dominant offshore to longshore winds into elongated embryo dunes over this upper beach, imprinting a regional morphology of long‐term longshore dune ridge development. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

12.
In this study, the decadal evolution of a washover fan on the west coast of Denmark is examined from its initial generation in 1990 until 2015. Since its inception, the bare and flat washover fan surface has recovered and accreted slowly due to re-activation by overwash during surges and due to aeolian activity and dune formation, stimulated by vegetation growth. The volume of sand on the washover has increased steadily at an average rate of about 23 m3/yr per unit length of shoreline, and a total of 175,000 m3 of sand is now deposited on the fan, while at the same time the shoreline has receded by some 250 m. The evolution can be divided into three stages: 1) An initiation phase when storm surge levels and energetic wave conditions caused a breach in the foredunes and overwash processes formed a washover fan with a relatively low elevation above mean sea level; 2) An initial recovery phase during which waves supplied sand to the fan during frequent overwash activity and winds transported this sand into marginal dunes surrounding the fan; and 3) A later recovery phase when the surface of the fan had accreted to a level where vegetation could survive and trap sediment into new foredune growth across the fan. The rate of accretion has been overall linear but scales with neither annual overwash frequency, nor with aeolian transport potential. Instead, the linear accretion is more closely related to the steady onshore migration of nearshore bars that weld to the beach and provide a sand supply for transfer to the fan. The fan evolution demonstrates the importance of washover fans in preserving barrier resilience during transgressional phases caused by increasing mean sea level. © 2019 John Wiley & Sons, Ltd.  相似文献   

13.
This paper discusses a model which simulates dune development resulting from aeolian saltation transport. The model was developed for application to coastal foredunes, but is also applicable to sandy deserts with transverse dunes. Sediment transport is calculated using published deterministic and empirical relationships, describing the influence of meteorological conditions, topography, sediment characteristics and vegetation. A so-called adaptation length is incorporated to calculate the development of transport equilibrium along the profile. Changes in topography are derived from the predicted transport, using the continuity equation. Vegetation height is incorporated in the model as a dynamic variable. Vegetation can be buried during transport events, which results in important changes in the sediment transport rates. The sediment transport model is dynamically linked to a second-order closure air flow model, which predicts friction velocities over the profile, influenced by topography and surface roughness. Modelling results are shown for (a) the growth and migration of bare, initially sine-shaped dunes, and (b) dune building on a partly vegetated and initially flat surface. Results show that the bare symmetrical dunes change into asymmetric shapes with a slipface on the lee side. This result could only be achieved in combination with the secondorder closure model for the calculation of air flow. The simulations with the partly vegetated surfaces reveal that the resulting dune morphology strongly depends on the value of the adaptation length parameter and on the vegetation height. The latter result implies that the dynamical interaction between aeolian activity and vegetation (reaction to burial, growth rates) is highly relevant in dune geomorphology and deserves much attention in future studies. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

14.
Early‐stage aeolian bedforms, or protodunes, are elemental in the continuum of dune development and act as essential precursors to mature dunes. Despite this, we know very little about the processes and feedback mechanisms that shape these nascent bedforms. Whilst theory and conceptual models have offered some explanation for protodune existence and development, until now, we have lacked the technical capability to measure such small bedforms in aeolian settings. Here, we employ terrestrial laser scanning to measure morphological change at the high frequency and spatial resolution required to gain new insights into protodune behaviour. On a 0.06 m high protodune, we observe vertical growth of the crest by 0.005 m in two hours. Our direct measurements of sand transport on the protodune account for such growth, with a reduction in time‐averaged sediment flux of 18% observed over the crestal region. Detailed measurements of form also establish key points of morphological change on the protodune. The position on the stoss slope where erosion switches to deposition is found at a point 0.07 m upwind of the crest. This finding supports recent models that explain vertical dune growth through an upwind shift of this switching point. Observations also show characteristic changes in the asymmetric cross‐section of the protodune. Flow‐form feedbacks result in a steepening of the lee slope and a decline in lower stoss slope steepness (by 3°), constituting a reshaping of protodune form towards more mature dune morphology. The approaches and findings applied here, (a) demonstrate an ability to quantify processes at requisite spatial and temporal scales for monitoring early‐stage dune evolution, (b) highlight the crucial role of form‐flow feedbacks in enabling early‐stage bedform growth, alluding to a fluctuation in feedbacks that require better representation in dune models, and (c) provide a new stimulus for advancing understanding of aeolian bedforms. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

15.
Vegetation plays an important role in shaping the morphology of aeolian dune landscapes in coastal and semi‐arid environments, where ecogeomorphic interactions are complex and not well quantified. We present a Discrete ECogeomorphic Aeolian Landscape model (DECAL) capable of simulating realistic looking vegetated dune forms, permitting exploration of relationships between ecological and morphological processes at different temporal and spatial scales. The cellular automaton algorithm applies three simple rules that lead to self‐organization of complex dune environments, including nebkhas with distinctive deposition tails that form in association with mesquite‐type shrubs, and hairpin (long‐walled) parabolic dunes with trailing ridges that evolve from blowouts in association with vegetation succession. Changing the conditions of simulations produces differing landscapes that conform qualitatively to observations of real‐world dunes. The model mimics the response of the morphology to changes in sediment supply, vegetation distribution, density and growth characteristics, as well as initial disturbances. The introduction of vegetation into the model links spatial and temporal scales, previously dimensionless in bare‐sand cellular automata. Grid resolutions coarser than the representative size of the modelled vegetation elements yield similar morphologies, but when cell size is reduced to much smaller dimensions, the resultant landscape evolution is dramatically different. The model furthermore demonstrates that the relative response characteristics of the multiple vegetation types and their mutual feedback with geomorphological processes impart a significant influence on landscape equilibria, suggesting that vegetation induces a characteristic length scale in aeolian environments. This simple vegetated dune model illustrates the power and versatility of a cellular automaton approach for exploring the effects of interactions between ecology and geomorphology in complex earth surface systems. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

16.
The complex morphodynamic interactions between nearshore, shoreface and dune systems are usually simplified by studying these zones and their associated processes in isolation. However, the established relationships between each of them suggests that an integrated approach is required to examine the genesis, evolution and adaptation of the entire morphodynamic system. The Cabopino dune system in the southern Spanish Mediterranean Sea provides a clear example of a linked morphodynamic system in which a relatively large dune system has been generated and grown through the supply of sediments from an adjacent littoral supply environment. Here, we present a conceptual model of how the nearshore has provided suitable conditions for beach and dune development. We purport that synchronization of sediment activation in the marine and aeolian sections of the system have played a major role in this microtidal setting in which temporal aspects are not only tied to storm action, but to large sedimentary features moving alongshore. © 2019 John Wiley & Sons, Ltd.  相似文献   

17.
Aeolian sand landforms in the Yarlung Zangbo River valley can be divided into 4 classes and 21 types. The river valley has favourable environment conditions for the development of aeolian sand landforms. Simulation of MM4 mid-scale climate model showed that the near-surface flow field and wind vector field during the winter half year in the river valley are generally favourable for the aeolian sand deposition and as a whole they also affect the distribution mneu and sites of aeolian sand landforms. Sand dunes and sand dune grouup in the river valley developed mainly in three ways, namely windward retarding deposition, leeward back flow deposition and bend circumfluence deposition. Through alternating positive-reverse processes of sand dune formation under wind actions and sand dune vanishing under water actions, sand dunes developed fmm primary zone thmugh main-body zone then to vanishing zone where climbing dunes and falling dunes are declining and are even disappearing. Project supported by the National Natural Science Foundation of China (Grant No. 49471009) and Xi’an State Key Laboratory of Loess and Quaternary Geology (Grant No. 9401)  相似文献   

18.
盐湖中的矿物沉积记录着丰富的环境气候变化信息,是古环境研究的重要对象.在无地表径流补给的盐湖中,其矿物组成及沉积特征与有地表径流补给的湖泊相比是否有一定的特殊性,是值得探讨的问题.采集巴丹吉林沙漠33个不同矿化度地下水补给型湖泊的表层沉积物和10个地表风积砂样品,通过X衍射的方法,分析样品的矿物组成.结果显示:湖泊表层沉积物主要为石英、长石、辉石、云母等碎屑矿物,部分湖泊含有少量的碳酸盐和氯化物盐类矿物.湖泊沉积物的矿物组成与湖水矿化度的关系较为密切,淡水湖仅分布碎屑矿物,微咸水湖含有碎屑矿物和碳酸盐类矿物,盐湖含有碎屑矿物、碳酸盐类矿物和氯化物.风积砂样品中主要为碎屑矿物,占总矿物含量的90%,对湖泊沉积物的矿物组成影响较大,但对湖泊沉积物中的盐类矿物没有贡献,表明湖泊表层沉积物中盐类矿物主要是自生作用形成的.虽然本地区湖泊边缘的沉积物中盐类矿物种类相对较少并且含量较低,但其盐类矿物组成与分布能够响应湖水矿化度的变化,其环境指示意义与有径流补给的盐湖相同,可以指示其湖水的盐度.因此,可以从巴丹吉林沙漠地下水补给型湖泊沉积的盐类矿物中提取相应的古环境信息,用于恢复古气候和古环境的研究.  相似文献   

19.
A forward modeling approach is proposed to simulate the preservation potential of tidal flat deposits. The preservation potential is expressed as a function of net deposition rate and a factor that represents the vertical flux of suspended load, or seabed lowering during erosion periods associated with bedload transport. The model takes into account a number of geometric parameters of a tidal flat sediment system and sediment dynamic processes. The former includes high water level, total sediment supply, the annual rate of the supply, the ratio of mud to bilk sediment in the supply, the bed slope of the tidal flat profile, as well as the slope of the stratigraphic boundary; the latter includes spring-neap cycles of tidal water level changes, boundary layer processes, resuspension of fine-grained sediments, bedload transport due to tidal currents, and bed elevation changes in response to sediment movement. Using this model, numerical experiments are carried out for a tidal flat system on the Jiangsu coast, eastern China, with the input data being derived from literature and from a series of sediment cores collected along an onshore–offshore transect. The results show that the preservation potential is highest over the upper part of the inter-tidal zone and in the lower part of the sub-tidal zone, and lowest near mean sea level and at low water on springs. The preservation potential tends to decrease with the advancement of the shoreline. The bed slope, tidal current direction and resuspension intensity influence the spatial distributions of the preservation potential. An implication of these results is that the temporal resolution of the tidal flat record depends upon the location and depth within the deposit; this should be taken into account in the interpretation of sedimentary records. Further studies are required to improve the model, on the hydrodynamic processes associated with extremely shallow water depths, sediment dynamic modeling of bed slope and profile shape, and the combined action of tides and waves for sediment transport on tidal flats.  相似文献   

20.
The wide spatial coverage of sand dunes in continental interiors makes the understanding of their activity and accumulation history valuable for palaeoenvironmental reconstructions and the interpretation of landscape evolution. Nevertheless, the study of aeolian landscape development at the million-year timescale is hampered by the complex interaction of factors determining dune migration and the inherently self-destructive nature of their chronostratigraphy, thus limiting the applicability of traditional dating methods. This study presents a standalone program that simulates aeolian transport based on luminescence-derived chronologies coupled with numerical modelling of the accumulation of cosmogenic nuclides. This integrative approach to modelling the history of aeolian landforms reveals phases of emergence of aeolian sand into the landscape, and provides a data-based scheme that facilitates the morphodynamical study of aeolian processes over multiple timescales and up to several millions of years. The application of the program for reanalysing previously reported data from the Australian Simpson Desert reveals multiple pulses of sand dispersion into central Australia at 3.8–3.4, 2.9–2.5 and 1.5–1 Ma, corresponding to pronounced changes in climatic conditions and landscape deformation events. The synchronicity of the results with the established environmental framework that would promote the production and aeolian distribution of sand exemplifies the applicability of process-based modelling in constructing a timeframe of key landscape evolution events in arid environments by studying aeolian deposits. The dependence of the parameters used to determine environmental settings on sand transportation patterns additionally makes the program a powerful tool to further investigate the triggers and mechanisms of aeolian processes.  相似文献   

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