Chronostratigraphy ; Dating ; Dune ; Eolian features ; Holocene ; Quaternary ; Sand ; United States ; Wyoming
The primary subject of this paper is a test of optical dating using sand-sized quartz grains from an independently well-dated Holocene dune sequence from the Ferrisdunefield, Clear Creek, Wyoming. The use of a stratigraphic sequence provides
Eolian activity had begun in the Ferris-Lost Soldier area by at least ca. 9,950 to 10,330 years b.p. Major depositional intervals (indicating widespread Ferrisdune activity) correlate with two radiocarbon-dated periods of drought. The first
occurred between ca. 7,660 and 6,460 years b.p.| the second occurred following ca. 6,460 years b.p. (and lasted until ca. 5,500 years b.p.). Since the last major depositional (drought) interval, the climate in the Ferris-Lost Soldier area has moderated
. Drought intervals have been short and vegetation has largely stabilized the dunes.
Aeolian features ; Aeolian transport ; Arid area ; Desert ; Dune ; Earth surface processes ; Sand ; Wind
Longitudinal dunefields characteried by nearly uniform interdune spacing are distinguished from longitudinal dunefields characterized by fairly variable interdune spacing and high frequencies of dune coalescence. The empirical and theoretical
timescale is estimated for the formation of desert longitudinal dunefields.
evidence indicating that the former may be due to helical air currents aligned with the dunes is reviewed. Hypotheses arguing that the latter may arise indirectly from horizontal pressure gradients or bidirectional wind regimes are dicussed An evolutionary
Aeolian dunefield self-organization - implications for the formation of simple versus complex dune-field patterns
Auto-organisation ; Dune ; Eolien ; Géomorphologie littorale ; Simulation par ordinateur ; Système complexe
Aeolian features ; Coastal geomorphology ; Dune ; Self-organizing behaviour
Les dunes et les champs de dunes comme systèmes complexes. Implications pour les types de champs de dunes simples et complexes. Les variations à l'intérieur de types de dunes simples. Les surfaces géomorphologiques et les archives de roches.
The AA. demonstrate the effect seasonal inter-dune freshwater ponds have on the bleaching of the color of sand dunes by iron reduction in the anaerobic conditions they create. By combining spectral measurements of field samples of dune sand together
with the analysis of satellite images covering 3 dunefields in the NE Brazil, they demonstrate its existence in the field. Interpretations of dunes age based on their color should be handled with care.
Sedimentology and development of parabolic dunes, Grande Prairie dunefield, Alberta
Alberta ; Canada ; Dune ; Eolien ; Grande Prairie ; Géographie de l'Amérique ; Structure sédimentaire ; Sédimentologie
Etude des variations de la forme des dunes paraboliques en fonction du régime sédimentaire et des séquences sédimentaires préservées dans les dunes de Grande Prairie, Alberta, Canada.
Aeolian features ; Dune ; Earth surface processes ; Model ; Simulation ; Wind speed
The AA. analyse Werner's dune-field simulation model for the uni-directional wind regime leading to the evolution of transverse dunes. Following this, they introduce 2 revisions to the Werner model, which lead to dunes that more closely resemble
those in nature. The first revision incorporates wind structure over a dune, and the second considers the wind speedup and the equilibrium dune shape.
Results of field work studying the mecanism of movement and advance for longitudinal dunes shows that wind that encounters longitudinal dunes obliquely is deflected on the lee flank and blows along that flank parallel to the crest line.
Aquitaine ; Barchan ; C 14 dating ; Classification ; Coastal environment ; Dune ; France ; Geochronology ; Geomorphology ; Holocene ; Palaeosol
The coastal dunefield of Aquitaine is one of the most extensive in Europe, which was fixed during the 19th century. This paper proposes a new chronology and a morphological classification for the dune systems found in Médoc.
Aeolian features ; Bahia ; Barchan ; Brazil ; Coastal deposit ; Coastal dune ; Coastal environment ; Geochronology ; Holocene ; Quaternary ; River mouth ; Sea level
This paper documents the morphology and the environmental controls responsible for the formation and evolution of the São Francisco strandplain dunefields with major emphasis on the active dunes. Three morphological provinces in the active coastal
dunesfields are recognized. This study suggests that the aeolian sedimentation is a relatively recent phenomenon at the Quaternary strandplain of the São Francisco River.
Aeolian features ; Classification ; Coastal environment ; Delaware ; Dune ; Estuary ; Human impact ; New Jersey ; Sand ; Topography ; United States of America
are derived from field surveys conducted in two relatively large ria-type estuaries (Raritan Bay and Delaware Bay) on the northeastern coast of the United States. A generic classification is presented for typical dune forms, identifying their dimensions
The purposes of this paper are to identify the processes on estuarine shorelines that affect aeolian transport and dune development and to provide an explanation for the great variety in dune types and their dimensions. Data on dune characteristics
Bagnold's model for the formation of seif dunes from barchans supported by Lancaster (1980), is reviewed. A new model was developed based on field work done in the northern Sinai desert that does not differentiate between the effects of strong
Nearest neighbor methods applied to dunefield organization : the Coral Pink Sand Dunes, Utah, USA
Analyse de voisinage ; Dune ; Eolien ; Etats-Unis ; Géomorphologie ; Photographie aérienne ; Système d'information géographique ; Technique de recherche ; Utah
Aeolian features ; Aerial photography ; Dune ; Geographical information system ; Geomorphology ; Research technique ; United States of America ; Utah
Using the Coral Pink Sand Dunes in southern Utah as a model, this study tests nearest neighbor analysis adapted as a method to objectively identify and characterize differences in two dimensional dune patterns within a dunefield and to identify
changes in dune patterns over time. Reducing transverse and barchanoid dunes from linear to three-point features in planar space emphasizes the clustering that occurs when dune lengths and wave lengths are more disorganized or random. This clustering may
Analyse statistique ; Auto-organisation ; California ; Domaine aride ; Dune ; Eolien ; Etats-Unis ; Géomorphométrie ; Mauritanie ; Namibie ; New Mexico ; Système
Aeolian features ; Arid area ; California ; Dune ; Geomorphometry ; Mauritania ; Namibia ; New Mexico ; Self-organizing behaviour ; Statistical analysis ; System ; United States of America
, the Agneitir in Mauritania, and the Namib in Namibia. The results are consistent with models of dunefields as self-organizing complex systems in which a characteristic pattern emerges as a function of constructional time.
As a basic form of pattern analysis, the parameters of dune spacing, defect density, crest orientation and crest length are measured from remote images and treated statistically for dunes at White Sands in New Mexico, the Algodones in California
Morphological development of dunes in a subarctic environment, central Kobuk Valley, northwestern Alaska
Alaska ; Barkhane ; Dune ; Eolien ; Fluviatile ; Géographie physique ; Kobuk vallée ; Paléo-environnement ; Photo-interprétation ; Transport éolien ; Zone froide ; Zone subarctique
The morphology of the dunefields is described by airphoto interpretation supplemented by field observations. Dune forms indicate that both present-day and former wind directions are parallel to the valley axis. Therefore it is proposed that wind
Cette image de SEASAT couvre la majeure partie du champ de dunes de Sonora. Les différentes structures éoliennes y apparaissent en clair parce que les surfaces lisses sans végétation des dunes réfléchissent spéculairement l'énergie du radar.
Aeolian features ; Aggregate ; Clay ; Dune ; Indiana ; Lithology ; Pedogenesis ; Stratigraphy ; United States of America ; Weathering
Three parabolic dunes from the Fair Oaks Dunefield in northern Indiana were excavated, in order to study the properties and genesis of lamellae. In this paper, the AA. demonstrate petrogenic (depositional) origin of these lamellae.
Aeolian features ; Digital elevation model ; Dune ; Geographical information system ; Geomorphometry ; Lake ; Michigan ; Sand ; United States of America
This study assesses the geography and volume of coastal dune sand along Lakes Huron and Michigan in Lower Michigan. Dunefield extents were obtained from digital maps of critical dune area and soil parent material. Volumetric estimates were
determined by establishing basal surface elevations and then calculating the average height of overlying dune deposits using digital elevation model (DEM) data within a raster GIS framework. Results and discussion.
A new expression describing the migration of aeolian dunes
Analyse quantitative ; Chine ; Domaine aride ; Dune ; Eolien ; Equation semi-analytique ; Gansu ; Granulométrie ; Mars ; Minqin ; Sable ; Simulation ; Transport éolien ; Vitesse de frottement ; Vitesse du vent
Aeolian features ; Aeolian transport ; Arid area ; China ; Dune ; Friction velocity ; Gansu ; Grain size distribution ; Mars planet ; Quantitative analysis ; Sand ; Simulation ; Wind speed
Based on quantitative simulations on the formation and evolution of aeolian dunefields, a semi-analytical equation describing the migration of aeolian sand dunes with respect to dune height, annual wind regime, frictional wind speed, and sand grain
diameter is proposed in this paper through analyzing the migration speeds of aeolian sand dunes with different heights in a dunefield. The migration speeds of aeolian sand dunes on Earth predicted by the equation is consistent with field observations
proposed by this paper can also be used to determine the annual wind regime and wind speed in dunefields for given dune speed and sand diameter.
, and it can be applied to describe the migration of underwater sand dunes and aeolian snow dunes on Earth, as well as that of aeolian sand dunes on other planets, for example Martian sand dunes. In addition, the A-W (annual wind regime-wind speed) method