Aeolian Landscape Research Articles

Monsoon control on evolution of the western Indian aeolian landscape: Insights from U-Pb detrital zircon geochronology and Sr-Nd-Hf isotope studies of the Thar Desert sand dunes

Evolution of landscape is linked to the interplay of tectonics, lithology, and climate. To better understand the evolution of aeolian landscape of the western Indian subcontinent and its major driver/s, we carried out a quantitative provenance analysis of the sand dunes of Thar Desert and desert river Luni using whole rock Sr-Nd-Hf isotopes and detrital zircon U-Pb geochronology. Our findings show Himalayan origin for the Thar sands. River Indus consistently contributed about 30–40 % of the total dune sand across the desert. The sand dunes in the north and the west of the desert are dominated by sediments derived from the source rocks drained by Sutlej river and its tributary Beas river whereas the dunes of central Thar are dominated by sediments supplied by rocks drained by Jhelum, Ravi and Chenab rivers. Analysis of detrital zircon U-Pb age spectra of sediments from desert river Luni reveal that dune sand of southern Thar Desert forms nearly 80 % of its present-day sediment load. Notably, the Thar dune sands show remarkable compositional similarity to the early to middle Holocene Indus delta sediments suggesting shared source/s. Existing paleolimnological and climatic records suggest a wetter environment in the Thar during early to middle Holocene. This evidence coupled with compositional similarities between the Thar dunes and the Indus delta sediments from the same period, indicate a probable extension of the Indus-Sutlej floodplain into southeast Thar during that time. Subsequent aridification of the region in the late Holocene likely led to seasonal winds recycling this fluvial sand to form the present-day Thar dunes, and shaping the current aeolian landscape in western India.

Landscape-Scale Modeling to Forecast Fluvial-Aeolian Sediment Connectivity in River Valleys.

Sedimentary landforms on Earth and other planetary bodies are built through scour, transport, and deposition of sediment. Sediment connectivity refers to the hypothesis that pathways of sediment transport do not occur in isolation, but rather are mechanistically linked. In dryland river systems, one such example of sediment connectivity is the transport of fluvially deposited sediment by wind. However, predictive tools that can forecast fluvial-aeolian sediment connectivity at meaningful scales are rare. Here we develop a suite of models for quantifying the availability of river-sourced sediment for aeolian transport as a function of river flow, wind regime, and land cover across 168 km of the Colorado River in Grand Canyon, USA. We compare and validate these models using topographic changes observed over 10 years in a coupled river sandbar-aeolian dunefield setting. The models provide a path forward for directly linking fluvial hydrology with the management and understanding of aeolian landscapes.

The fault in our TARs: A critical review of research paradigms for intermediate‐scale bedforms on Mars

AbstractWe provide a critical review of research paradigms for classifying intermediate‐scale aeolian bedforms on Mars and the new terminology that has emerged. The systematic classification of bedforms has always been challenging and debated, and no paradigmatic knowledge organization system exists beyond general agreement on the importance of a distinction between ripples and dunes. The diverse aeolian landscapes of Mars have introduced further topics and challenges to these debates. We argue that Martian aeolian geomorphology's knowledge organization system for intermediate‐scale bedforms is preparadigmatic and that consensus over terminology and their definitions has not been established in the literature. A preparadigmatic science can be functional only if scientists operating in the discipline provide precise, falsifiable definitions or use abductive logic. Drawing on evidence and examples from the literature, we argue that the replacement of the conventional abductive paradigm used in bedform classification with inductive logic has created an emerging disciplinary paradigm based on scientific hesitancy and a dependence on complex inductive research structures, epitomized by the concepts of ‘transverse aeolian ridges’ (TARs) and ‘large Martian ripples’ (LMRs). We show that TAR and, increasingly, LMR are inductive constructs that have been popularized despite them causing significant confusion. Notably, we highlight how the terms are irreconcilably used as both a class of bedform and as a non‐genetic placeholder term for bedforms. Suggestions for moving beyond the need for TAR and LMR are provided, focusing on a return to more direct and local hypothesis‐driven research inspired by W.M. Davis's notion of outrageous geological hypotheses. Recent debate surrounding bedforms in Gale crater is presented as an example of the productivity of such an approach, and it is recommended that TAR and LMR no longer be used.

Do topographic changes tell us about variability in aeolian sediment transport and dune mobility? Analysis of monthly to decadal surface changes in a partially vegetated and biocrust covered dunefield

Vegetation and biological soil crust (biocrust) cover can have a stabilizing effect on dunes by fixing sediment in-place and increasing surface roughness, thus limiting dune mobility, sediment transport, and erosion. These biological effects influence rates of aeolian activity and thus surficial changes, though variability in wind and sediment supply may obscure these topographic effects. In this study, we compare monthly measures of sediment transport and decadal estimates of dune mobility to repeat topographic changes measured as a net volume change in sediment storage (difference in volume between all positive and negative topographic changes) and total volume change (absolute summed volume of all positive and negative changes) for areas of bare, vegetated, and biocrusted sand within a dunefield with limited sediment supply and unimodal winds. We found that monthly net volume changes normalized by area were similar between bare sand and sand with at least 20 % vegetation cover. However, total volume change was significantly greater for bare sand and correlated with monthly sediment flux estimates (R2 = 0.46), though the relationship was significantly improved by including monthly changes in surface roughness (R2 = 0.8). Longer-term decadal trends in topographic change showed larger total volume changes with the greatest decreases in vegetation canopy cover. Additionally, decadal total volume changes strongly correlated with estimates of dune mobility (R2 = 0.99). We also found that increased total volume changes did not necessarily signal increased net volume changes for all land cover types. Specifically, increases in total volume change for bare sand resulted in near equal or lower net volume changes, as both positive (deposition) and negative (erosion) change increased with sediment transport. Conversely, less mobile land covers, such as biocrust covered sand, increased in erosion without significant increases in total volume change, demonstrating that more stable surfaces might exhibit a larger topographic change imbalance than mobile sediment surfaces under the same conditions. This study highlights the importance of considering multiple measures of topographic change for interpreting sediment mobility, transport, and availability. Additionally, we hypothesize a novel framework for remote sensing-based empirical studies aimed at interpreting aeolian landscape evolution resulting from climate change effects on weather as well as biological controls such as vegetation and biocrusts.

Landscape dynamics of the aeolian savanna: Santos Luzardo National Park 1988–2018

This research defines the savanna aeolian landscape dynamics of the ‘Santos Luzardo’ National Park in the Llanos of Venezuela between 1988 and 2018, using images from the LANDSAT series to elaborate and compare ecosystems maps. The ecosystem dynamics show that the landscape changes naturally since the transitions occurred towards other types of natural savanna due to soil water seasonality. The savannas are the dominant matrix of the landscape, occupying between 69.1 and 76.7%. The dynamics of transformation of the aeolian savanna landscape are mainly associated with soil water content. The application of temporal studies contributes to understanding the aeolian savanna landscape transformation processes and evaluating their conservation status.

Exploring the transition between water- and wind-dominated landscapes in Deep Springs, California, as an analog for transitioning landscapes on Mars

Abstract. Many planetary surfaces have been shaped by eolian and fluvial processes, and understanding the resulting landscape is of critical importance to understanding changes in climate. Surface features on Earth and Mars are commonly observed using a variety of remote sensing methods. The observed geomorphology provides evidence of present processes and paleo-processes, but interpretations are limited by the resolution of the data and similarity to well-understood systems on Earth. In this work, we study a complex fluvio-lacustrine and eolian landscape at Deep Springs playa, California, using field measurements and remote sensing as an analog for a wet-to-dry-transitioning landscape on Mars. The playa system in arid Deep Springs reflects fluvio-lacustrine processes in its interior but transitions to eolian-dominated processes along the playa margin. Weather station data and field observations collected over 34 months illustrate the interplay between eolian and lacustrine processes and provide context for interpreting the observed geomorphology in aerial images. Our results showed a consistent distal-to-proximal geomorphic transition in the landscape defined by the changing expression of polygonal fractures, wave ripples, and evaporite deposits. Crescent-shaped sedimentary deposits, originally suspected to be related to barchan dunes, proved unrelated to eolian processes. We discuss the processes, sedimentary features, and climate drivers at Deep Springs to provide a potential framework for identifying and interpreting similar interactions between fluvio-lacustrine and eolian geomorphology elsewhere on Earth, on Mars, and beyond.

Establishing cordgrass plants cluster their shoots to avoid ecosystem engineering

Abstract Vegetated coastal ecosystems such as salt marshes, dunes and seagrass meadows occur at the land–sea interface—a dynamic environment typified by harsh growing conditions. These ecosystems are known as biogeomorphic landscapes because their functioning depends on biophysical interactions by which organisms engineer landforms to their own benefit. The strength of such biogeomorphic feedbacks depends on plant traits, such as stem flexibility and shoot density. Recent work demonstrated that dune grasses with similar morphological traits can build contrasting landscapes due to differences in their spatial shoot organization. However, in contrast to dune grasses that trap and stabilize sand particles in aeolian landscapes, flow attenuation in aquatic environments can generate scouring around plant stems and cause uprooting, leading to establishment thresholds for young plants. Yet, it remains unknown how findings from aeolian landscapes translate to aquatic systems and how young clonally expanding plants in hydrodynamically exposed conditions overcome these establishment thresholds by optimizing shoot placement. Here, we measured shoot patterns of 90 establishing cordgrass patches Spartina anglica at 18 European field sites that cover a broad range of hydrodynamic conditions. Next, we carried out a field experiment to investigate how observed spatial shoot patterns affect plant–sediment feedbacks. Surprisingly, field survey analyses reveal highly consistent clustered shoot patterns, regardless of environmental conditions. Experimental results demonstrate that this clustered pattern minimizes scouring compared to densely clumped organizations typically observed in established patches. Synthesis. In contrast to earlier findings highlighting that establishing dune grasses optimize their landscape engineering capacity via a flexible shoot placement strategy, we find that cordgrass instead follows a fixed strategy that minimizes engineering effects in its early life stages. We suggest that marsh grasses avoid physical stress and associated establishment thresholds in their early life stage, and switch to an ecosystem engineering strategy once established. These findings shed new light on how plant traits interact with their environment to shape the landscape and pave the way for improved restoration designs by mimicking the natural shoot organization of establishing vegetation. Read the free Plain Language Summary for this article on the Journal blog.

Formation and reorganization time scales of aeolian landscapes

AbstractLandscapes created through sediment transport are shaped by the interaction of flow and form. In landscapes where wind is the agent of geomorphic work, this is clear at the small scale; equilibrium dune morphology is linked to the wind climate and the supply of sediment. At larger scales, this linkage becomes ambiguous because the form of giant dunes and dune fields integrates long histories of varied wind and sand supply. Without a framework to assess aeolian landscape evolution at this scale, the time taken to form and reorganize dune fields has been largely unexplored quantitatively. We show that these time scales can be understood by linking modern wind and topographic data sets for one of the most expansive and morphologically diverse unvegetated dune fields, the Rub’ al Khali (southern Arabian Peninsula). By linking sediment flux to the surface area and slope of dunes, and growth to the divergence in that flux, we fully couple form and flow at the dune field scale. Our results show quantitatively how dune field formation and reorganization are outpaced by climate change and the implications for stratigraphic interpretation.

Optically stimulated luminescence dating and paleoclimatic implications of the Holocene dune sands in the Hunshandake Sandy Land, Northeast China

Aeolian sediments are important geological archives of paleoclimate changes. Due to the fragile ecosystem of desert, sand dune mobility is particularly sensitive to climate change, and is thus important for revealing the stabilization and mobilization processes of dunes during the geological past. In northeastern China, several sandy lands are located in the East Asian monsoonal region, and desert evolution has been used to infer the waxing and waning of monsoonal climate. However, the relationship between dynamic aeolian landscapes and forcing mechanisms is still under debate due to the complex nature of the aeolian dune systems. In this study, we analyse two aeolian sand dune sections in the Hunshandake Sandy Land, northeast China, located at the northern edge of the East Asian summer monsoon, explore regional paleoclimatic changes during the Holocene. We carried out high-resolution optically stimulated luminescence (OSL) dating to develop a well-constrained chronology for the dune sands, as well as analyses of multiple climatic proxies including magnetic susceptibility, particle size, and color parameters, to obtain knowledge about dune mobility and climatic changes. Our results indicate that the early Holocene was characterized by the accumulation of aeolian dune sands, implying an arid climate, driven by an enhanced East Asian winter monsoon. Paleosols were generally developed in the mid-Holocene (∼8 and 4 ka) when the sand dunes were stabilized by vegetation under a relatively warm and humid climate driven by an enhanced East Asian summer monsoon. In the late Holocene, from ∼4 ka to the present, climate returned to an arid and semi-arid phase, marked by aeolian dune sands with some weakly-developed paleosols. Through comparison of the aeolian record with the other East Asian monsoonal records and the sea-surface temperature of the North Pacific, we suggest that the evolution of the East Asian monsoon, which was paced by both the melting and expansion from the Northern Hemisphere ice sheet as well as the changes of solar radiation, played an important role in driving climate change in the Hunshandake Sandy Land during the Holocene.

High-resolution, spatially resolved quantification of wind erosion rates based on UAV images (case study: Sistan region, southeastern Iran).

Estimating the quantitative distribution of wind erosion rates is one of the most important requirements for managing affected environments and optimizing locations to control wind erosion. This study develops high-resolution maps for wind erosion with unmanned aerial vehicles or UAV images in the Sistan region-an area in southeastern Iran with severe wind erosion. Aerial imaging by UAV was done during period of erosive winds. Changes in the amount of wind erosion were measured for 7months. Digital elevation models or DEM with a spatial resolution of 6mm, orthophoto mosaic images with a resolution of 3mm, were prepared before and after the erosion event. Three erosive facies consisting of surface, edge, and blowout were identified. The amount of erosion in different geomorphological landscapes or facies was measured according to differences of DEMs (DOD). The effect of physical factors of the geomorphological landscapes on wind erosion was investigated by calculating the correlation between the erosion, roughness, and slope in the geomorphological landscapes. The results showed that the highest and lowest mean of eroded soil were 22mm and 4mm in the blowout and surface facies, respectively. The average rate of wind erosion was 201 t/ha during the study period, which indicates the high intensity of wind erosion in the Sistan plain. Overall, UAV-as an aerial imaging technique collecting ground data-can be a helpful tool in the aeolian geomorphology especially for collecting data for measuring the rate of soil erosion by the wind in the aeolian landscapes located in remote regions.

Late Holocene environmental and hydro-climatic variability inferred from a shallow lake record, blowout dunes, Argentinian western Pampas, South America

The Pampas plains of southern South America were predominantly dry, eolian-shaped landscapes, besides some interposed humid phases, during most of the late Pleistocene-Middle Holocene, evolving to humid-subhumid grasslands hosting an increasingly large number of shallow lakes in the late Holocene. These lakes proved to preserve in their sediments worthy evidence to interpret past environmental-ecological conditions, offering tools to analyze climatic variability and human impacts during the last millennia. This is the case of the shallow lake Primera Laguna, located in the western and driest edge of the Pampas. Here, we present a multiproxy study from this shallow lake with the aims of contributing to reconstruct its past stages, infer the climatic scenarios that drove its evolution, evaluate the potential anthropogenic role in these changes, and correlate/analyze this record with available data from other Pampean lakes. We analyzed a high-resolution palynological record, accompanied by macroscopic charcoal accumulation rates, C/N, C and N stable isotopes, magnetic susceptibility, and sediment geochemistry, of a 41-cm long sediment core, extracted from the deepest sector of the lake. An age-depth model based on AMS chronology indicates a preserved lake history for the past ∼1400 cal yr BP. Ecological and sedimentological interpretations allowed us to propose four main periods during this time lapse. For the first period (1375–1069 cal yr BP, 575–881 CE), the integrative interpretation indicates a very low shallow lake –mostly oligotrophic, alkaline, and clear water–, dominated by the accumulation of epiclastic silty fine sand from the surrounded eolian landscape and covered by xerophytic vegetation. In the second period, between 1069 and 738 cal yr BP (881–1212 CE), we inferred a trend to rising lake levels and mesotrophic conditions, and more pollen taxa than the previous period, and with lake margins dominated by cattails and sedges. The third period (738–193 cal yr BP, 1212–1757 CE) was characterized by more variable and lower lake levels compared to previous periods and more frequent desiccation processes at the lake margins. Then, during the fourth period (last 195 cal yr, 1757–2015 CE), there was a gradual transition towards a larger and more stable shallow lake with a deeper water column, and under a turbid state probably related to eutrophication. From the comparison between Primera Laguna record and the previously studied Nassau shallow lake, located in the same eolian landscape, we found a synchronic evolution, implying common drivers of change in terms of climatic variability and human impact. Correlation with shallow lakes from the more humid belt of the Pampas suggests widespread increases of water availability in the region since ∼1500 cal yr BP, variable/lower lake levels during ∼600–200 cal yr BP, and a shift to positive hydrological balances up to the present highstands.

Multisource Classification of Meridiani Planum's Aeolian Landscape Using HiRISE and Opportunity Images Analysis Based on Deep Learning

The aim of the research was to analyze the possibilities of using deep learning methods for classifying multi-source image data for Mars. It should be emphasized that the main goal of the research was to develop a methodology for integrating image data acquired from orbiters (MRO mission's HIRISE camera) and in situ (Opportunity rover's NAVCAM camera) and to use their combined analytical potential. We used a VGG-16-based network for this study, which is well-characterized in the literature and has been successfully applied in a wide range of applications. The article proposes a methodology for the supervised classification of landforms on Mars. The proposed solution was evaluated using the Meridiani Planum area, utilizing neural network deep learning and was based on multi-source image data. We found that our approach classified aeolian reliefs correctly for more than 94% of the test dataset. The classification accuracy increased to almost 96% when using panoramas developed from Opportunity's images and the derivatives of the digital terrain models used during the classification process. It is possible to broaden the proposed concept of multi-source classification and the customized deep learning system to the analysis of other regions of Mars and to multispectral imaging without losing the generalizability of the solution.

Using photographic measurement and gigapixel panoramas to study changes in a Lake Michigan sand dune

Detailed measurements of changes in aeolian landscapes help researchers better understand aeolian processes and monitor the effects of climate change in these systems. This study focuses on a photographic method to measure sand surface changes. It introduces custom erosion pins (photoscale pins) designed to allow proper scaling of measurements taken from digital images or high resolution (gigapixel) panoramas. Furthermore, this study discusses errors associated with measuring photoscale pins photographically. Resolution errors arise when marking object boundaries on digital images. These typically affect measurement precision, but even so, differences between repeated measurements of the same pin average 0.58 mm. Perspective errors arise when pins are tilted relative to the camera’s line of sight and introduce bias, affecting measurement accuracy. Photographic measurement can allow remote surveillance, reduce site disturbance, increase the frequency of observation, and reduce measurement error compared to manual measurement of erosion pins. A study of sand movement in a dune complex on the southeastern shoreline of Lake Michigan provides an example of the method’s application. Photoscale pin measurements that bracket a wind event associated with Hurricane Sandy show average surface elevation changes of 3.97 cm/pin. Regional wind data, pin measurements, and surface changes recorded in gigapixel panoramas suggest that vegetation baffling, recirculation eddies, and topographic steering played roles in sand deposition and erosion at the site. Photographic measurement of erosion pins can complement wind instrumentation and other tools as aeolian research increasingly incorporates multiple techniques to study surface changes in greater detail both in time and space.

The Cosmolian program for simulating aeolian dynamics and its application to central Australia

AbstractThe 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.

The Aeolian Environment of the Landing Site for the ExoMars Rosalind Franklin Rover in Oxia Planum, Mars

AbstractAeolian features at Oxia Planum—the 2023 landing site for the ExoMars Rosalind Franklin Rover (ERFR)—are important for Mars exploration because they record information about past and current wind regimes, sand transport vectors, and lend insight to the abrasion, deposition, and transport of granular material. To characterize the wind regime and erosional history of Oxia Planum we used a combination of manual observational and machine‐learning techniques to analyze the morphometrics, distribution, and orientation of 10,753 aeolian bedforms (Transverse Aeolian Ridges[TARs]) and landforms (Periodic Bedrock Ridges [PBRs]) around the ERFR landing ellipses. We found that, irrespective of the scale of the TARs, crestline azimuths are consistent across the study area and we infer that the bedform forming winds blew from NW‐NNW toward SE‐SSE. PBR azimuths show a substantively different orientation to the aeolian bedforms, and we infer that the winds necessary to abrade PBRs had a N‐NNE or S‐SSE orientation (180° ambiguity). From observations of active dust devils and windstreaks from repeat imagery, we infer a W‐WNW or E‐ESE (180° ambiguity) wind dominates today. Finally, we compare the inferred wind direction results from the aeolian landscape to modeled wind data from Mars Global Circulation Models. We note that, despite landscape evidence to the contrary, modeled contemporary wind direction lacks the consistent directionality to be responsible for the orientation of aeolian features in Oxia Planum. These results characterize aeolian features ERFR will encounter and suggests multiple wind regimes have influenced the surficial expression of the landing site.

Ancient Aeolian Landscapes of the South of Western Siberia: Issues of Protection and Nature Management

One of the distinctive features of the West Siberian Plain is the wide distribution on its territory of cover sandy deposits, which act as parent rocks over a large area within the region for a wide range of climatic conditions. This feature of Western Siberia is due to geological and geomorphological conditions and the history of relief development in the Late Quaternary. Soils formed on sandy deposits play an important role in the sustainable functioning of the landscapes of the entire West Siberian region. This article discusses the issue of the protection of unique ancient aeolian landscapes on the example of the south of Western Siberia.

Unveiling buried aeolian landscapes: reconstructing a late Holocene dune environment using 3D ground‐penetrating radar

ABSTRACTAcross the UK, sandy beaches and dunes protect coastal infrastructure from waves and extreme water levels during large‐scale storms, while providing important habitats and recreational opportunities. Understanding their long‐term evolution is vital in managing their condition in a changing climate. Recently, ground‐penetrating radar (GPR) methods have grown in popularity in geomorphological applications, yielding centimetre‐scale resolution images of near‐surface stratigraphy and structure, thus allowing landscape evolution to be reconstructed. Additionally, abrupt changes in palaeo‐environments can be visualized in three dimensions. Although often complemented by core data, GPR allows interpretations to be extended into areas with minimal ground‐truth control. Nonetheless, GPR data interpretation can be non‐intuitive and ambiguous, and radargrams may not initially resemble the expected subsurface geometry. Interpretation can be made yet more onerous when handling the large 3D data volumes that are facilitated with modern GPR technology. Here we describe the development of novel semi‐automated GPR feature‐extraction tools, based on ‘edge detection’ and ‘thresholding’ methods, which detect regions of increased GPR reflectivity which can be applied to aid in the reconstruction of a range Quaternary landscapes. Since reflectivity can be related to lithological and/or pore fluid changes, the 3D architecture of the palaeo‐landscape can be reconstructed from the features extracted from a geophysical dataset. We present 500 MHz GPR data collected over a buried Holocene coastal dune system in North Wales, UK, now reclaimed for use as an airfield. Core data from the site, reaching a maximum depth 2 m, suggest rapid vertical changes from sand to silty‐organic units, and GPR profiles suggest similar lateral complexity. By applying thresholding methods to GPR depth slices, these lateral complexities are effectively and automatically mapped. Furthermore, automatic extraction of the local reflection power yields a strong correlation with the depth variation of organic content, suggesting it is a cause of reflectivity contrast. GPR‐interpolated analyses away from core control thus offer a powerful proxy for parameters derived from invasive core logging. The GPR data collected at Llanbedr airfield highlight a complex dune system to a depth of 2.8 m, probably deposited in several phases over ~700 years, similar to elsewhere in North Wales.

Псаммофитная растительность Баргузинской котловины (Республика Бурятия)

Псаммофитная растительность Баргузинской котловины (Республика Бурятия)

Evolution and formation of Martian aoli landscape

The entire surface of Mars is characterized by aeolian activity with typical elements on its surface. The conditions of formation and evolution of the Martian aeolian landscapes are considered. Using the MGD3 base, a hypsometric map of the Hellas Planitia region with longitudinal dunes at a scale of 1: 100,000 was created. It is important that the study of aeolian landforms on Mars makes it possible to better understand the Martian climate and the global circulation of its atmosphere.

The Teewah Transect: GPR-Derived Insights into the Younger Dune Morphosequences on the Great Sandy Coast, Queensland, Australia

Gontz, A.; McCallum, A.; Ellerton, D.; Patton, N., and Shulmeister, J., 2020. The Teewah Transect: GPR-Derived Insights into the Younger Dune Morphosequences on the Great Sandy Coast, Queensland, Australia. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 500-504. Coconut Creek (Florida), ISSN 0749-0208. The world's largest sand islands lie off the coast of southeast Queensland, Australia. Between these islands, mainland coastal sand masses, bedrock promontories and rivers exist in low-lying areas. Sediment is sourced from one of the world's longest downdrift systems, transporting sand eroded from sandstones in New South Wales north over 1000 km. Recent work has shown the coastal dune fields have been periodically active for the last million years, at times of high and intermediate sea-levels, and identified a series of aeolian morphosequences that exhibit an onlapping relationship with evidence of significant reworking of more seaward morphosequences to create more landward low-relief aeolian landscapes. In 2012, a campaign that collected over 300 km of ground penetrating radar data was begun to understand the stratigraphic framework of this sand-rich system.. One of the surveys acquired a transect over the dune environment of the southern tip of the Cooloola Sand Mass near the town of Teewah. At this location, the dune field narrows to less than 1.5 km with 20-25 m of relief. The seaward side is characterized by eroding dunes and high bluffs. Moving inland over the highest portion of the dune field, the landscape slopes gently to a near sea level with a pluvial-fluviallacustrine dominated system that drains directly to the Noosa River and the Coral Sea. GPR surveys revealed a complex stratigraphy including primary sediment structures related to aeolian processes overprinted with podzol soil development resulting in post depositional features that range from well-developed soil sequences to incipient horizons. Recent GIS mapping has identified this area as consisting of primarily Holocene systems. The Teewah Transect is presented as a case study demonstrating a spatial relationship of the morphosequences and examines the aeolian-soil relationships at the far southern tip of the Cooloola Sand Mass.