Download or read book Three Dimensional and Multi Temporal Dune Field Pattern Analysis in the Olympia Undae Dune Field Mars written by William David Middlebrook and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fields of sand dunes are ubiquitous in the north polar region of Mars and provide a record of sand transport processes influenced by Mars' polar climate. Spatial and temporal variations in dunes, ripples, coarse-grained ripples, and exposed dune cross-strata were analyzed in two areas of the Olympia Undae Dune Field in order to assess the influence of the Martian polar boundary conditions on ripple and dune activity and on pattern development. Two- and three-dimensional parameters, including dune crest length, spacing, width, slope, and height, were statistically assessed using regression analysis and descriptive statistics. Sediment fluxes were calculated using Co-registration of Optically Sensed Imagery and Correlation (COSICorr), a program that precisely co-registers and correlates imagery, and by measuring dune displacement. Two-dimensional pattern analysis indicates the co-existence of two populations of dunes that can be interpreted as two generations or as forming simultaneously under sediment availability limited conditions. Three-dimensional pattern analysis shows an asymmetry in slope profiles of the primary dunes and is consistent with primary dunes forming transversely to constructional winds. Four different types of ripple crestline patterns are identified and likely arise due to differences in grain size and dune-modified wind speeds and secondary flow directions. Maximum measured ripple displacement in the center of Olympia Undae study area is ~1.4 m yr−1 ± 0.13 m. Assuming a mean ripple height of 0.11 m and a 4:1 saltation to reptation ratio, the sediment flux is ~0.42 m3 m−1 yr−1. Adjacent to the polar ice cap, barchan dune crest displacements range between 0.25 m yr−1 and 2.80 m yr−1 and dune heights between 11 m and 31 m. Mean sediment flux is 3.5 m3 m−1 yr−1. Results indicate that there is a spatial decay in sediment transport across the field and that fluxes near the cap are comparable to those found in Nili Patera, Mars and Victoria Valley, Antarctica. Overall the polar boundary conditions seasonally limit sand availability by seasonal frost cover and subsurface ice. The polar boundary conditions are most influential at the dune pattern scale, but appear to have little influence on the ripple pattern or ripple mobility. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155559

Download or read book Martian Gullies and their Earth Analogues written by S.J. Conway and published by Geological Society of London. This book was released on 2019-01-21 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gullies on Mars resemble terrestrial gullies involved in the transport of abundant material down steep slopes by liquid water. However, liquid water should not be stable at the Martian surface. The articles in this volume present the two main opposing theories for Martian gully formation: climate-driven melting of surficial water-ice deposits and seasonal dry-ice sublimation. The evidence presented ranges from remote-sensing observations, to experimental simulations, to comparison with Earth analogues. The opposing hypotheses imply either that Mars has been unusually wet in the last few million years or that it has remained a cold dry desert – both with profound implications for understanding the water budget of Mars and its habitability. The debate questions the limits of remote-sensing data and how we interpret active processes on extra-terrestrial planetary surfaces, even beyond those on Mars, as summarized by the review paper at the beginning of the book.

Download or read book Sand Dunes of the Northern Hemisphere written by Qi Lu and published by CRC Press. This book was released on 2023-03-10 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book in two volumes, and with a foreword by the renowned Professor M.A.J. Williams, draws on evidence from coastal and inland regions, including desert dunes, wind-blown dust, river and lake sediments, glacial moraines, plant and animal fossils, isotope geochemistry, soils and prehistoric archaeology to better understand the genesis and development of dunes systems in selected northern hemisphere sand dunes from Asia, Africa and the Middle East regions. The collection of research papers and case studies that are presented in this book provide the reader with a wealth of information about the distribution and types of sand dunes and an insight into the complexity of sand dune formation, migration and management. Research in many countries across the northern hemisphere shows that dunes, whether coastal or inland, are under pressure around the world. Much of the pressure comes from human activities, and the anthropogenic disturbance, when coupled with global warming and alterations to the amount, frequency and temporal distribution of precipitation could lead to more serious management challenges in the future. There is much that we still need to find out about the origin, genesis and development of sand dunes so that they can be managed better. The difficult and complex questions being repeatedly raised can be answered only by interdisciplinary endeavours. Geomorphologists, geologists, palaeontologists, climatologists, ecologists, and others, can work together on research projects that better define the origin, evolution and development of dunes, both inland and along the coasts. Many chapters in this book attempt to reconstruct past climatic changes in deserts and their margins at a variety of scales in space and time in the expectation that such information might assist in preparing us for future global warming and drying.

Download or read book Dune Worlds written by Ralph D. Lorenz and published by Springer Science & Business Media. This book was released on 2014-04-22 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes how sand dunes work, why they are the way they are in different settings, and how they are being studied. Particular attention is paid to their formation and appearance elsewhere in the solar system. New developments in knowledge about dunes make for an interesting story – like the dunes themselves, dune science is dynamic – and the visual appeal of Aeolian geomorphology ensures that this is an attractive volume. The book is divided into 4 parts, the first of which introduces dunes as a planetary phenomenon, showing a landscape reflecting the balance of geological processes – volcanism, impact, tectonics, erosion, deposition of sediments. Dunes are then considered as emergent dynamical systems: the interaction of sand and wind conspires to generate very characteristic and reproducible shapes. Analogies are given with other emergent structures such as patterned ground before the influence of dunes on desert peoples and infrastructure is studied, together with their use as forensic climatological indicators. Dune Physics is looked at with regard to the mechanics of sand, the physics of wind, saltation – interaction of sand and air – dunes versus ripples and transverse Aeolian ridges, the classification of dune morphology and the sources and sinks of sand. Dune Trafficability considers soil mechanics, effects on mobility on Earth, Mars and elsewhere. In the second part, Earth, Mars, Titan and other moons and planets are examined, beginning with a survey of the major deserts and dunefields on Earth. The authors then turn to Mars and its environment, sediment type, dune stratigraphy, sediment source and sinks and the association of dunes with topographic features. Titan follows - its thick, cold atmosphere, methane dampness, low gravity, morphology – interaction with topography and the implications of dunes for climate and winds. Dunes elsewhere conclude this part. There are few dunefields on Venus, but there is a .possibility of Aeolian transport on Triton and volcanic-related windstreaks on Io.

Download or read book Modeling Aeolian Dune and Dune Field Evolution written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling aeolian dune and dune field evolution.

Download or read book Aeolian Dune Dynamics and the Stratigraphic Record written by Sarah Christian Brothers and published by . This book was released on 2016 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dunes and dune fields are dynamic features that respond to the unique boundary conditions under which they evolve by changing migration habits, types and frequencies of interactions, and morphologies. As such, dunes convey information about changing atmospheric and surface conditions on planetary bodies including Earth, Mars, Venus, and Titan, and the stratigraphic record left by these bedforms is used to interpret the evolution of paleoclimate and surface environments. In four parts this work examines how the dynamics of individual dunes, dune fields, and aeolian systems influence stratigraphic architectures across multiple spatial scales. At White Sands Dune Field, New Mexico, the decadal histories of defect and bedform repulsion-type interactions are traced through a time-series of images. The resultant stratigraphic architectures are derived from plan-view exposures and ground penetrating radar sensing of dune interiors. This is the first documentation of the unique stratigraphic architectures that result from interactions between dunes. Within Chasma Boreale, Planum Boreum, Mars, boundary conditions controlling the discrete geomorphic expressions of the Hyperboreae Undae dune fields are evaluated using morphologic distributions. The distributions reveal that dune field expressions change over short horizontal scales and are dependent upon wind regime and sediment state, which operate under the background condition of dune induration by ice. Hyperboreae Undae form only part of the Chasma Boreale sediment system, however. Perennial layered ice deposits also are present on the floor of the reentrant. The changing balance of ice- and sand-dominated processes in space and time have resulted in an accumulation that transitions between ancient aeolian cavi unit-style accumulation and modern layered ice deposit-style accumulation. These accumulations can be interpreted through aeolian sequence stratigraphy. Findings from the Chasma Boreale transitional sediment system are applied to nearby outcrops of a transitional section of ancient cavi unit, which formed in an environment analogous to the modern Chasma Boreale sediment system. A sequence interpretation of the transitional cavi unit stratigraphic succession demonstrates how the aeolian system transitioned into overlying water ice deposits without a gap in the geologic record, verifying that the cavi unit and NPLD should be unified under a sequence stratigraphic framework.

Download or read book Dunes written by Andrew Warren and published by John Wiley & Sons. This book was released on 2013-04-03 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dunes is the first book in over a decade to incorporate the latest research in this active and fast-developing field. It discusses the shapes, sizes, patterns, distribution, history and care of wind-blown dunes, and covers all aspects of dunes, terrestrial and in the Solar System. The only book to cover all dunes, terrestrial and in the Solar System, in deserts, on coasts, and in the past Represents the most current update on the research of dunes for over a decade Incorporates the latest research to come out of China where the field is most rapidly expanding Discusses the most recent range of skills and technology now focused on the study of dunes Brings up-to-date a rapidly expanding field

Download or read book Aeolian Dune field Boundary Conditions and Dune Interactions Related to Dune field Pattern Formation on Earth and Mars written by Ryan Cotter Ewing and published by . This book was released on 2009 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Patterns and Paleoshorelines of White Sands Dune Field New Mexico written by Elke Elise Baitis and published by . This book was released on 2011 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dune field at White Sands, New Mexico, shows a well-defined pattern of dunes and interdune areas, as well as spatial variations in this pattern. The purpose of this research is to determine which measured pattern parameters are most consistent across the dune field and to determine the cause of depositional spatial variability. This was accomplished using an airborne LiDAR generated digital-elevation model (DEM) collected in June 2007 and covering 39 km2 of the dune field. Properties of the dune field are defined by measurements from three dune populations: 1) 110 randomly selected dunes, 2) 247 dunes along transects oriented in the net transport direction, and 3) 171 dunes from three zones within the field where differences in pattern are visible. Measurements of eight common dune parameters show that the lowest coefficients of variation occur with dune orientation and crestline sinuosity, which largely define the field pattern. Cross-plotting of parameters shows generally poor correlations, which is thought to reflect variation around field-scale means that are comparable to other dune fields globally. Removing the dunes from the LiDAR DEM reveals a depositional substrate with breaks in slope interpreted as three paleoshorelines associated with Pleistocene Lake Otero. The paleoshorelines are antecedent boundary conditions that exert the primary control on spatial variability within the dune pattern.

Download or read book UNDERSTANDING FORMATION AND EVOLUTION OF DUNE FIELDS BY SPATIAL MAPPING AND ANALYSIS written by Paul W. O'Malley and published by . This book was released on 2019 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: The morphology of vegetation-stabilized parabolic dunes has been seen as a source of climate information from their periods of stabilization. Several dune fields in the upper Muskegon River Valley in central Michigan, including fields not previously described in the literature, were mapped using Geographic Information System (GIS) based techniques. The mapping used terrain analyses, derived from a digital elevation model (DEM) and a Light Detection and Ranging (LiDAR) based terrain model in tandem with semi-automated based extraction followed by manual refinement of delineation and visualization techniques (VT). Terrain parameters and VT also guided digitization of dune crestlines. The morphology of the mapped dunes was characterized in terms of slope and aspect relationships, and comparisons were evaluated. Directional statistics were used to describe crestline orientations and circular variance. The morphology of these dune fields likely reflects a climate having an unequal bimodal wind regime, the dominant regime being northwesterly and the secondary regime being southerly or southwesterly. Based on visual interpretations, the location of downwind, compound parabolic forms are linked to locations likely to have had shallow groundwater, or to possibly suitable locations for parkland that could have induced precipitation ridges marking downwind dune field margins. Elongated dune forms are linked to rising terrain. Exploratory data analysis (EDA), primarily based on slope and aspect correlations, revealed a strongly asymmetric distribution in slopes of the fields, indicating the potential that a bimodal wind regime was present when the dunes stabilized. Cross-cutting relationships between dunes and terraces of the Muskegon River were observed which place formation of the dunes before the formation of paleo-meanders by a forerunner to that stream. The planform and distribution of the dunes in the dune fields also appear closely tied to the changing groundwater availability.

Download or read book Dune Pattern Dynamics on a Multi decadal Scale at the White Sands Dune Field New Mexico written by David Rachal and published by . This book was released on 2007 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pattern Analysis of Aeolian Dune Crests in White Sands New Mexico written by Joe Kendall Salinas and published by . This book was released on 2015 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aeolian dune fields are among the most significant examples of patterns seen in nature. Laterally linked barchanoid dunes create a crescentic region within the White Sands Dune Field in New Mexico. Physical mapping of the dunes within the crescentic region using Google Earth allowed for naturally occurring patterns and downwind trends in Aeolian systems to be identified. The patterns have been interpreted as the outcome of self-organizing phenomena that arise within the complex system of sediment transport. The dimensions (arc length and width) of the mapped dune crest segments consistently decrease in the downwind direction across White Sands. However, the sinuosity of the dune crest segments (the curvature of the laterally linked bedforms) is consistent across White Sand Dune Field. Lastly the numbers of mapped segments within a dune crest were recorded in the downwind direction. This information regarding the change in the quantity of segments downwind shows that as dune crest lengths increase in size, the number of dune segments within a dune crest increase downwind. These measured parameters allow for a better understanding of the morphology of crescentic dunes as they exchange sediment and migrate downwind. The data is also complementary to previous pattern analyses conducted in White Sands.

Download or read book Geomorphology of Desert Dunes written by Nicholas Lancaster and published by Cambridge University Press. This book was released on 2023-02-28 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sand dunes are a globally important depositional landform and sedimentary system. Their origins and dynamics are important in understanding how deserts have evolved in response to climate change and changes in sand supply and mobility, and how they will continue to evolve in the future. This book provides a state-of-the-art review of the characteristics of desert dunes and their sediments, and explores their dynamics on timescales from days to millennia as they respond to changes in wind speed and direction, precipitation and sand supply. This extensively revised edition reflects the advances in our understanding of desert dunes, their dynamics and history; and covers recent developments including the luminescence dating revolution, ground penetrating radar and advances in numerical modeling. Also covering dunes on Mars and Titan, this authoritative reference is a must-have for researchers and graduate students working on desert dunes and aeolian geomorphology.

Download or read book Sand Dunes of the Northern Hemisphere Distribution Formation Migration and Management written by Lu Qi and published by CRC Press. This book was released on 2024-01-09 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 2 of the book ‘Sand Dunes of the Northern Hemisphere’ is sub-titled Characteristics, Dynamics and Provenance of Sand Dunes in the Northern Hemisphere. It brings together a vast body of information and insight into sand dune and desert systems from North Asia, Central Asia, North Africa and the Middle East. Chapters from the Russian Federation include studies on dune systems within the permafrost zone and there is a case study from temperate zone dune system in coastal Japan. Volume 2: Characteristics, Dynamics and Provenance of Sand Dunes in the Northern Hemisphere of 16 chapters in three Parts, focusses on Saharan Africa, Egypt, and Middle East and gives attention to sand mobility and encroachment with case studies from a number of countries where these matters are of concern. We also include chapters on the remote dunes in the permafrost zone and in the hyper-arid deserts of Iran. Case studies are used to highlight the characteristics of dunes and their interaction with humans in several widely divergent settings. Volume 2 concludes with some musing on the value of study of the past as key to the future and speculates on what the future might hold in the light of a warmer and drier Earth and a rise in sea level that threaten large tracts of low-lying land with marine incursions and destruction from storm surge. PART 4 Sand Mobility and Encroachment The seven chapters in this Part examine the real-world impact of sand encroachment and dune migration on people and their economic activities and the health, welfare and financial implications related to destruction of infrastructure, including human habitations. PART 5 Sand Dune Landscapes Distribution, Formation and Management Seven Case studies from several geographic regions in Africa, the Middle East, north-east Asia are presented here to demonstrate the underlying mechanisms in dune formation and the diverse approaches to their management. Human impacts such as sand mining, tourism development, combine with natural forces like climate variability to challenge the realization of an optimum management strategy. PART 6 Concluding Thoughts: Coping with an Unknown Future from a Little-known Past The two chapters in Part 6 have special roles. We are privileged to publish new research findings that are summarized here in Chapter 38 from extensive and detailed work conducted in the Kyzyl Kum, and Karakum sand seas of Central Asia. There is a strong belief that further study of the little-known past such as revealed in this study could unlock clues as to what a future Earth might look like. This leads on to speculation in Chapter 39 about the implications of what we already know about global change (not only climate change) and the impact of the Anthropocene on the dune systems, both inland and coastal. Sea level rise, marine incursions and an increase in extreme weather events will affect dune systems and sand seas on the Northern Hemisphere (and beyond).

Download or read book Implications of Dune Pattern Analysis for Titan s Surface History written by Christopher Jon Savage and published by . This book was released on 2011 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analyzing dune parameters such as dune width and spacing can be useful in determining the reaction of dunes to changes in atmospheric and sedimentary conditions currently and in the recent geological past. Dune parameters, dune width and spacing, were measured for linear dunes in regions across Saturn's moon Titan from images T21, 23, 28, 44, and 48 collected by Synthetic Aperture RADAR aboard the Cassini spacecraft in order to reconstruct the surface history of Titan. Dunes in the five study swaths are all linear in form, but lack superimposed or flanking dunes. They have a mean width of 1.3 km and mean crest spacing of 2.7 km, wider and farther apart on average than similar terrestrial dunes in the Namib and Agneitir Sand Seas though larger linear dunes exist on Earth. Because of the lack of superimposed and flanking dunes and their size, Titan's dunes are classified as very large simple linear dunes. The large size, spacing and uniform morphology are all indicators that Titan's dunes are very mature and long-lived features. The ratio of dune width to spacing for Titan's dunes is similar to that found in terrestrial dunes in that dune spacing tends to be twice dune width. In addition to being similar in size, this is further evidence that terrestrial dunes can be used as analogues for Titan's dunes and vice versa and that the essential dune-forming processes are the same on both bodies. Dune width and spacing decrease northward, which is attributed to, but not limited to, increased maturity of dune fields to the south or increased sediment stabilization to the north. Sediment stabilization may be caused by Titan's asymmetric seasons and a net transport of moisture from south to north. The majority of dunes have spacings consistent with an upper limit of 2 to 4 km established by the atmospheric boundary layer, further evidence they are mature. Dunes are more widely spaced in the south are evidence they have been growing toward a steady state for a longer period of time than those in the north. Titan's large linear dunes have long reconstitution times. This is in part due to the fact that winds sufficient for saltation are reached only near the Titan equinox every 14 Earth years. Based on rates for similar terrestrial dunes the reconstitution time for Titan's dune is 600,000 Earth years or more, and therefore substantial changes in dune form should not be observable over Cassini's lifetime. Cumulative probability plots of dune parameters measured at different locations across Titan indicate there is a single population of dunes on Titan. This suggests that, unlike analogous dunes in the Namib and Agneitir Sands Seas, dune-forming conditions that currently exist on Titan are either the only dune-friendly conditions in the moon's history, or the current conditions have been stable and active long enough to erase any evidence of past conditions.

Download or read book Modeling Aeolian Dune and Dune Field Evolution written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling aeolian dune and dune field evolution.

Download or read book Implications of Dune Pattern Analysis for Titan s Surface History written by Christopher Savage Savage and published by . This book was released on 2011 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analyzing dune parameters such as dune width and spacing can be useful in determining the reaction of dunes to changes in atmospheric and sedimentary conditions currently and in the recent geological past. Dune parameters, dune width and spacing, were measured for linear dunes in regions across Saturn's moon Titan from images T21, 23, 28, 44, and 48 collected by Synthetic Aperture RADAR aboard the Cassini spacecraft in order to reconstruct the surface history of Titan. Dunes in the five study swaths are all linear in form, but lack superimposed or flanking dunes. They have a mean width of 1.3 km and mean crest spacing of 2.7 km, wider and farther apart on average than similar terrestrial dunes in the Namib and Agneitir Sand Seas though larger linear dunes exist on Earth. Because of the lack of superimposed and flanking dunes and their size, Titan's dunes are classified as very large simple linear dunes. The large size, spacing and uniform morphology are all indicators that Titan's dunes are very mature and long-lived features. The ratio of dune width to spacing for Titan's dunes is similar to that found in terrestrial dunes in that dune spacing tends to be twice dune width. In addition to being similar in size, this is further evidence that terrestrial dunes can be used as analogues for Titan's dunes and vice versa and that the essential dune-forming processes are the same on both bodies. Dune width and spacing decrease northward, which is attributed to, but not limited to, increased maturity of dune fields to the south or increased sediment stabilization to the north. Sediment stabilization may be caused by Titan's asymmetric seasons and a net transport of moisture from south to north. The majority of dunes have spacings consistent with an upper limit of 2 to 4 km established by the atmospheric boundary layer, further evidence they are mature. Dunes are more widely spaced in the south are evidence they have been growing toward a steady state for a longer period of time than those in the north. Titan's large linear dunes have long reconstitution times. This is in part due to the fact that winds sufficient for saltation are reached only near the Titan equinox every 14 Earth years. Based on rates for similar terrestrial dunes the reconstitution time for Titan's dune is 600,000 Earth years or more, and therefore substantial changes in dune form should not be observable over Cassini's lifetime. Cumulative probability plots of dune parameters measured at different locations across Titan indicate there is a single population of dunes on Titan. This suggests that, unlike analogous dunes in the Namib and Agneitir Sands Seas, dune-forming conditions that currently exist on Titan are either the only dune-friendly conditions in the moon's history, or the current conditions have been stable and active long enough to erase any evidence of past conditions.