Dune Formation Research Articles

Unexpected forms of sand dunes on Mars

Martian Geology On Earth, wind and water passing over sand result in the formation of large dunes or small ripples, collectively called bedforms. Lapotre et al. analyzed images of bedforms on Mars, taken from orbit and from the Curiosity rover on the surface. They found a third size of bedform on

Ecological Studies on The Vegetation of Sand Bar of Lake Burollos Protectorate and Effect of Salinity on Some Developing Species

Plant communities of Lake Burollos sand bar were analyzed using 30 stands (each 5×5 m) representing the different habitats by multivariate analysis. Four vegetation groups were identified using TWINSPAN analysis. These groups represent the main habitats recognized in the sand bar; Group A represents stabilized sand dunes indicated by Pancratium maritimum L., and Cyperus capitatus Burm F.; Group B of sand flat and mobile dunes with Alhagi Gracorum Boiss, and Elymus Farctus Viv as indicator species; Group C represents the salt marsh habitat with the indicator species Arthrocnemum Macrostachyum Moric. K., and Juncus Rigidus Desf; Young fore-dunes are represented by group D and the indicator species Cakile Maritime Scop. These groups are separated mainly on the basis of soil salinity, and age of sand dune formations along CCA-axis 1 and 2, respectively. The first axis of CCA separates halophytic species from psammophytes along soil salinity, organic carbon, and calcium carbonates gradients. The behavior of each species against the environmental severity and its relative importance in sand bar stabilization is explained. Responses of seed germination to salinity were examined musing 12 species collected from salt marshes stable dunes and fore dunes along the sand bar of Lake Burollos. Six concentrations of salt were added to plants grown in pots supported by nonabsorbent foam growth rate and the percentage of living material was measured. Also, a SWOT analysis will give more information to identify the key internal and external factors that are important to the conservation of plants in the Lake Burollos Protectorate Area.

CONTRIBUIÇÃO DO TRANSPORTE EÓLICO NO PROCESSO DE EVOLUÇÃO DA LINHA DE COSTA

This paper evaluates the eolian transport importance for the morphological behavior of a 20 Km stretch on the coast of Ceara between the Ceara river mouth and the Cumbuco Beach. The research consisted of the comparison between the sand volume involved in the coastline migration between 1974 and 2001 and the dune formation potential that is based on the relationship developed by the formed angle between the coastline position and the eolian transport dominant direction. The resulting material volume from the coastline migration was calculated by multiplying the advanced or retreated area by the sum of the active berm height and the closing depth. The dune formation potential, calculated for each studied segment, demonstrated (1) to keep an excellent correlation with the measured volumes for the coastline migration and (2) that most of the segments have been submitted to a sedimentary deficit potential caused by the wind, excluding a few stretches where there is a beach feedback tendency by the eolian transport, through a 'bypass' process. The results have showed that the eolian activity may be fundamental for the coastline equilibrium, reinforcing, this way, the idea that the works involving the coastal dynamics need the eolian transport study so that they may appropriately represent the coastal dynamics of the studied area.

Soil Paleocatenas, Prehistoric Land Use, and Coastal Landscape Dynamics at Druridge Bay, Northeast England

Coastal erosion of sand dune systems along Druridge Bay, northeast England, has progressively exposed parts of the subdune mid‐Holocene landscape, including paleocatenas, indicating former soil hydrosequences with localized wetland habitats, and archaeological evidence of human activities and land use from the Late Mesolithic to the Romano‐British period. Archaeological investigations and pedostratigraphic studies of paleosols provide a unique spatial–chronological framework to interpret soil and land use change over several millennia in the context of a changing coastal environment. Evidence includes dating of archaeological remains, the stratigraphy, morphology and micromorphology of buried soils and sediments, and the palynology and radiocarbon dating of subdune peats. Early Bronze Age burial sites were preferentially located on well‐drained hillocks also used for grazing. Adjacent wetland depressions provided areas of marshy grassland and swamp over deep fen peat soils that started to develop c. 5435 cal. yr B.P. in response to a rising groundwater table stimulated partly by slow sea‐level rise. The backslopes of the paleocatena were occupied by imperfectly to poorly drained soils that supported open oak‐hazel woodland with evidence for progressive clearance and use for agriculture. Windblown sand started to accumulate on the study site sometime between 3930 and 3670 cal. yr B.P., well before the Little Ice Age date for dune formation suggested by previous researchers.

The north-eastern aeolian ‘European Sand Belt’ as potential record of environmental changes: A case study from Eastern Latvia and Southern Estonia

Abstract The Latvian and Estonian inland dunes belong to the north-eastern part of the ‘European Sand Belt’ (ESB). These dunes are widely distributed over broad glaciolacustrine plains and Late Glacial alluvial deltas, considered to be potential sources for the aeolian material. Little is known about these aeolian sediments and their substratum; here we present a detailed sedimentary structural and textural characterisation together with a luminescence-based chronology. Through a comparison between grain-size, rounding of quartz grains and surface characteristics in medium/coarse (0.5–0.8 mm) sand, and the light mineral content, we found an alternation of aeolian and periglacial components. Further, short-lasting aeolian abrasion and/or transportation periods, and a significant contribution of a nearby sediment source are suggested. Luminescence dating points to aeolian sand accumulation and dune formation between ∼16 ka and ∼9 ka. However, we also observed some presumably watertable controlled environmental conditions at ∼13 ka; this corresponds with the occurrence of an ice-dammed/proglacial lake.

Coastal environment of the past millennium recorded by a coastal dune in Fujian, China

Coastal dune is a common aeolian geomorphology in a sandy coast, which records the evolution process of the aeolian landscape system and reflects the complex interaction among land surface, atmosphere and ocean. Coast is a sensitive area to global climate change. Restricted by chronology, most previous researches in China focused only on the cause of formation of coastal dunes. In recent years, the development of optically stimulated luminescence (OSL) dating provides a good method and acts as a carrier for coastal dunes to paleoclimate and paleoenvironmental studies. In this study, we selected an aeolian dune at the Anshan archaeological site, Fujian, China as the research object based on field observations. For determining their sedimentary stages and the primary influencing factors, we used the OSL dating method to construct a chronological framework for the aeolian dune. In addition, the sizes of grains were analyzed for identifying factors influencing the winter monsoon during the Medieval Warm Period (MWP) and the Little Ice Age (LIA) in this area. The results showed that the deposition of the aeolian dune was closely related to variations in the winter monsoon intensity. The changes of the winter monsoon were similar to the tendency of the East Asian winter monsoon, although there were several sub-fluctuations. From an overall perspective, the winter monsoon was strengthened during the MWP (1050–1300). The results of a power spectrum analysis showed that the intensity of the East Asian winter monsoon is correlated with sunspot activity.

Luminescence geochronology and paleoenvironmental implications of coastal deposits of southeast Cyprus

Quaternary stratigraphy and sea level changes have been extensively investigated in many areas of the Mediterranean. However, numerical dating of coastal deposits and the associated paleoenvironmental information are limited for the coasts of Cyprus, principally based on radiometric and radiation-exposure geochronological techniques on fossils which bear a range of limitations and uncertainties. As such, optically stimulated luminescence (OSL) dating techniques are deemed to be the most suitable in direct dating of the coastal sediments of Cyprus. In the southeastern Cyprus, coastal dunes (aeolianites) now forming elongated ridges appear as morphological features running parallel to the current shoreline presenting an indicator of sea level and climate changes of great paleoenvironmental significance. We present our first chronological results for the exposed aeolianites and underlying littoral deposits formed along the southeastern coastal Cyprus ranging from 78.4 ± 9.9 to 56.2 ± 7.4 ka. The post-infrared–infrared stimulated luminescence (pIR-IRSL) revealed that dune formation took place during the marine isotope stages (MISs) 3, 4, and possibly 5a. Late Holocene reworking is proposed for a distinctively isolated dune with an age of ~1.3 ka ago. This study also showed that pIR-IRSL dating of feldspars may be a reliable alternative to quartz OSL dating when the quartz luminescence characteristics are unsuitable.

EFICIENCIA DE LA Ammophila arenaria EN ATRAPAR SEDIMENTOS TRANSPORTADOS POR EL VIENTO.

The object of this paper was to evaluate the efficiency of the Ammophila arenaria in catching sediments. It was made by comparing sectors with dense vegetation cover and bare dunes (blowout), on foredunes at the central coast of Chile (38° 05 ' S). Vertical sand traps were placed across transects at the beginning of the dune formation, and at the base and the top of the foredune, in order to determine the aeolian sediment transport rates. The results showed that in the windward slope with dense vegetation the sand grains were trapped and an insignificant amount (3%) advanced behind the dunes. On the other hand, on the blowout, the sand windblown increased exponentially to the top reaching values up to 447% with respect to those found at the base of the blowout. The great capacity of the Ammophila arenaria in catching sediments is verified and it considers that foredunes with dense covers of Ammophila arenaria are like true natural traps for the evaluation of aeolian sand transport rates.

CFD–DEM simulations of current-induced dune formation and morphological evolution

Understanding the fundamental mechanisms of sediment transport, particularly those during the formation and evolution of bedforms, is of critical scientific importance and has engineering relevance. Traditional approaches of sediment transport simulations heavily rely on empirical models, which are not able to capture the physics-rich, regime-dependent behaviors of the process. With the increase of available computational resources in the past decade, CFD–DEM (computational fluid dynamics–discrete element method) has emerged as a viable high-fidelity method for the study of sediment transport. However, a comprehensive, quantitative study of the generation and migration of different sediment bed patterns using CFD–DEM is still lacking. In this work, current-induced sediment transport problems in a wide range of regimes are simulated, including ‘flat bed in motion’, ‘small dune’, ‘vortex dune’ and suspended transport. Simulations are performed by using SediFoam, an open-source, massively parallel CFD–DEM solver developed by the authors. This is a general-purpose solver for particle-laden flows tailed for particle transport problems. Validation tests are performed to demonstrate the capability of CFD–DEM in the full range of sediment transport regimes. Comparison of simulation results with experimental and numerical benchmark data demonstrates the merits of CFD–DEM approach. In addition, the improvements of the present simulations over existing studies using CFD–DEM are presented. The present solver gives more accurate prediction of sediment transport rate by properly accounting for the influence of particle volume fraction on the fluid flow. In summary, this work demonstrates that CFD–DEM is a promising particle-resolving approach for probing the physics of current-induced sediment transport.

Exploring Integrated Geophysics and Geotechnics as a Paleolandscape Reconstruction Tool: Archaeological Prospection of (Prehistoric) Sites Buried Deeply below the Scheldt Polders (NW Belgium)

AbstractDuring extensive construction works in Antwerp harbour, well preserved Late Glacial dune formations were discovered buried deeply below the Scheldt polders and covered by peat, organic matter (OM) rich clays and marine clayey to sandy sediments. First, coring based archaeological prospection strategies for evaluating prehistoric occupation levels in wetland landscapes are reviewed. Next, a more effective approach including near surface geophysical and geotechnical techniques is proposed and tested in Doelpolder Noord. The results indicate that high resolution electromagnetic induction survey at multiple coil spacing provides a suitable approximation of the prehistoric landscape variability but is challenged by variations in groundwater brackishness. Gridded cone penetration tests provide a solution in such cases and serve as an excellent interpretation tool for the conductivity data in general. Due to the required effort, electrical resistance imaging and shear wave land seismics were judged inefficient. Finally, a small dune with indications of paleosol conservation and estimated suitability for Final Palaeolithic to Early Neolithic occupation is sampled by Dutch hand augering and Sonic Drill Aqualock coring. Archaeological indicators for prehistoric occupation such as burnt bone and flint fragments were retrieved from these samples after sieving. Copyright © 2016 John Wiley & Sons, Ltd.

Origin of the reworked deposit in Sarugamori Sand Dunes : investigation of dune formation in Shimokita, northeast Japan

Origin of the reworked deposit in Sarugamori Sand Dunes : investigation of dune formation in Shimokita, northeast Japan

Assessing Late Pleistocene and Holocene phases of aeolian activity on the Nyírség alluvial fan, Hungary

There have been several studies addressing the timing and extension of Late Pleistocene and Holocene Aeolian activity in the Nyírség, the former alluvial fan of the Tisza River. Some of these already applied numerical dating techniques, however usually focused on one dune form or one site. This paper is an attempt on the one hand to review former age data and on the other hand to add new data from various sites to the landform evolution of the second largest sand dune area of the Carpathian Basin.The paper focuses on the Late Pleistocene–Holocene landform evolution of the second largest sand dune area of Hungary (Nyírség). Recent age data were obtained from investigations applying several methods (radiocarbon, OSL and palynological examinations) in order to determine the periods of sand movement and paleosoil formation in the area more accurately.According to the results, six sand movement periods can be identified during the Late Glacial and Holocen (Oldest Dryas, Younger Dryas, Preboreal Phase, Boreal Phase, Atlantic Phase, Subatlantic Phase).In between periods with intensive aeolian activity paleosoil formation occurred in the Bølling-Allerød Interstadial and in the Preboreal and Subatlantic Phases.

Middle to Late Pleistocene dunefields in rocky coast settings at Cala Xuclar (Eivissa, Western Mediterranean): Recognition, architecture and luminescence chronology

This study focuses on cliff-front anchored and sand-ramp aeolian dune accumulations in Cala Xuclar, Eivissa (Ibiza), Western Mediterranean, during different sea level falling stages from Middle to Late Pleistocene times. Stratigraphic mapping, conventional lithostratigraphic logging and OSL datings are used to reconstruct dune formation and evolution. Facies analyses result in the identification of six sedimentary units, three of which correspond to dune deposits formed at MIS 6 (145 ka), MIS 5d-c (∼100 ka) and MIS 4 (77–73 ka) respectively. Additionally there is a beach deposit at (∼2 m above present msl, which resembles the MIS 5a. This study concludes that each dune system corresponds to a relatively low sea-level stand that exposed enormous amounts of marine carbonate sands that was transported inland by migrating dunes under strong north–westerly winds. Therefore, sea-level fall and the related sediment supply owe likely to be key factors in the formation of these aeolianites systems.

Experimental flow characterization of sand particles for pneumatic transport in horizontal circular pipes

This work presents an experimental study carried out to simulate characteristics of turbulent air-sand particles flow through transparent horizontal pipes with various flow conditions. Experimental analysis focuses on the determination of critical pickup velocity of the solid particles from the horizontal sand layers. Mainly the effects of layer height and pipe diameter on the pickup velocity are investigated. Critical pickup velocity is determined by extrapolating the weight loss curves plotted as a function of corrected velocity above the sand layer. Experimental results show significant effects of layer height and pipe diameter on the pickup velocity. Saltation velocity and dune formation mechanisms are also discussed. Critical pick up velocity of solid particles is found to increase with increasing blockage ratio and pipe diameter. Inclination angle for larger sand bed heights caused leading edge effect on air flow entering the reduced cross sectional area above the layer. Sand particles pickup rate is found to decrease with time as a consequence of decreasing layer height. Experimental results have been correlated and compared with previous studies.

A Review on Late Quaternary Environmental Change in the Namibia, South-Western Africa

This paper focuses on the review of geomorphology and late Quaternary environmental change in the Namibia, south-western Africa. The relationship between geomorphology and climate in Namibia reveals the degree and extent to which its landscapes are determined by changing environmental conditions. Case studies of late Quaternary environmental changes in the northern, western and central Namibia are presented. Geomorphological analysis showed that the modern-scale landscape of the south and central Namibia is controlled primarily by tectonics and also by the lithology, base level and climate. At present there is debate on the behavior of Quaternary hydroclimate in the Namibia in response to precessional (19–23 kyr cycle) insolation variations and the effect of glacial versus interglacial boundary conditions. Clues from marine records regarding these debates were obtained. lower leaf-wax δD and higher δ13C (more C4 grasses) recorded in marine sediments over the last 140 ka indicates wetter summer conditions and increased seasonality during the Late Quaternary, particularly during Southern Hemisphere insolation maxima relative to minima and during the last glacial period relative to the Holocene and the last interglacial period. In the central and south-western Namibia, CNB dating suggests that the Namib Sand Sea has a residence time of at least 1 million years. Depositional ages of luminescence dating for dune sediments yields three broad areas of the sand sea, including MIS 5, later in the Pleistocene around the Last Glacial Maximum and the Holocene. The high coincidence of the luminescence ages of the linear dune complexes in the Kalahari over a distance of about 150 km suggests that dune activation in the south-western Kalahari was not the result of local effects but due to sub continental climatic changes. The major dates for dune forms in Kalahari at present are of Holocene age. In the northern Namibia, landscape degradation and desertification are developed during the Holocene. Humification of soils in this region suggests open savanna environments in the past and does not accord with the shrub lands and thornbush savanna at present. Landscape degradation seems to have started in pre-colonial times most likely as a consequence of cattle farming. These examples from different regions of the Namibia offers pointers as to how geomorphological evidence of Quaternary change can be used to assist in the better management of contemporary and future environmental conditions.

Factors controlling the formation of coppice dunes (nebkhas) in the Negev Desert

AbstractDue to their role in increasing fertility, coppice dunes (nebkhas) are regarded by many researchers as important contributors to aridland ecosystems. Yet, despite their frequent occurrence, little information exists regarding the rate and factors that control their formation. The goal of the current study is to examine the formation rate and factors that determine the establishment of coppice dunes in the Hallamish dune field in the western Negev Desert. The rate in which sand and fines, hereafter aeolian input (AI) was trapped and its particle size distribution (PSD) were examined by means of the solidification of 2 m × 2 m plots using surface stabilizers, and by the installation of three pairs of artificial shrubs (SH), three pairs of artificial trees (TR), and a pair of control (CT) plots. Measurements were annually conducted during June 2004 and June 2008, with monthly collection during June 2004 and May 2006. The PSD was compared to coppice dunes located on the fine‐grained playa surface. AI was trapped at SH, while it was not trapped at TR and CT. The annual rate of AI accretion under the canopy was highly variable ranging between 1405 and 13 260 g m−2, with a four‐year average of 5676 g m−2, i.e. 3.8 mm a−1. It depended upon the wind power, with drift potential having a threshold velocity of Ut > 10 m s−1 yielding the higher correlations with the monthly AI (r2 = 0.59–0.84). No significant relations were obtained between the monthly AI and shrub height. Sand saltation, suspension and creep are seen responsible for mound formation, which based on the current rates of sand accretion are relatively fast with a 60 cm‐high coppice dune forming within ~150–160 years. The current data highlight the problematic design of some previous research using conventional traps and confining the measurements only to certain seasons. Copyright © 2015 John Wiley & Sons, Ltd.

Grain‐size characteristics of dune networks in china's tengger desert

Grain‐size characteristics of dune networks in the Tengger Desert of northwestern China were investigated. Grain‐size parameters (mean, standard deviation, skew, and kurtosis) were determined on dune surfaces at windward toe, stoss, crest and leeward toe locations. Multiple discriminant analyses were applied to distinguish deposition environments. Results indicated that the aeolian sediment is mainly composed of very fine and fine sand in the dune networks of the Tengger Desert. Sorting improves as grain size becomes finer. However, the relationships between mean grain size, skew, and kurtosis vary in space. There is a negative relationship between skew and sorting; similarly, the relationships between sorting and skew, and skew and kurtosis change in space. The sediment deposition environment includes aeolian sediment and lacustrine sediment. The lacustrine sediment provides the source material for dune windward toe and stoss formation and development, but the aeolian sediment provides the source material for dune crest and leeward toe formation and development. According to the log‐probability of grain size distributions, aeolian sediments in dune networks are composed of two distinct saltation populations.

“VEGET ATION IMPACT ON THE DUNE STABI LITY AND FORMATION ON THE LITHUANIAN COAST OF THE BALTIC SEA”

"Corrigendum. 'Veget ation impact on the dune stabi lity and formation on the Lithuanian coast of the Baltic sea'."Journal of Environmental Engineering and Landscape Management, 23(4), p. 312

Evidence of Sequence and Age of Ancestral Lake Erie Lake-Levels, Northwest Ohio

While the general scheme of the retreat of the Late Wisconsinan glacier from the ancestral Lake Erie basin is understood, the sequence and timing of those movements that caused lake-level changes are not well documented. Ground penetrating radar (GPR), electrical resistivity (ER), and optically stimulated luminescence (OSL) techniques were used to analyze beach and sand dune formations in the Wauseon area in northwest Ohio. The beaches showed no evidence of being flooded after deposition. Thirteen (13) new OSL ages revealed a short time of approximately 1000 years (16.9–15.9 ka) for formation of the Maumee, Arkona and Whittlesey shorelines. Evidence supporting the Ypsilanti lowstand in the ancestral Lake Erie basin was not observed within two sequences of glacial lacustrine sediments. The results of OSL dating of sand dunes indicate a period of older activity (~14–15 ka) and confirmation of previous work that documented activity during the Younger Dryas cold period (~13–11.5 ka).

Spits formed in Glacial Lake Algonquin indicate strong easterly winds over the Laurentian Great Lakes during late Pleistocene

We report on a unique, new dataset: 49 spits that formed in the various phases of Glacial Lake Algonquin in the northern Great Lakes region, between approximately 13,200 and 11,500 years BP. The spits, which are now subaerially exposed well above the level of the current Great Lakes, trail off from former Lake Algonquin islands and headlands. Several exceed 10 km in length. Steep, eroded headlands coupled with their coarse-textured sediments, suggest that spit development was driven by large waves and strong longshore currents. The lake’s islands and exposed headlands are usually strongly eroded on their eastern margins. Additionally, spits within ≈150–200 km of the former ice margin, and especially the very large spits in northern Michigan, trail to the west, particularly the WNW and SW. Some small spits that lie farther south trail to the east, and others, within confined bays, better reflect the localized littoral circulation systems. Together, these features provide on-the-ground evidence for persistent, easterly, summertime winds in the late Pleistocene in the northern Great Lakes region, supporting paleoclimate models that show southeasterly to easterly air flows, originating from a glacial anticyclone above the Laurentide Ice Sheet. Our research suggests that strong, anticyclonically driven, easterly winds were a key part of the regional circulation within ≈150–200 km of the southern ice margin, while acknowledging that winds may have been more dominantly westerly at locations farther south. The latter conclusion reconciles with the record of loess transport and dune formation on westerly winds during this (and earlier) time periods in the south-central Great Lakes region and the Great Plains of North America.