Aeolian sedimentology

The study focuses on the Holocene appearance, chronology and drivers of beach sand deposition and inland aeolian sand transport along the Caesarea-Hadera dunefield. The dunefield extends 5.5 km inland from the current shoreline in the north-central coastal plain of Israel around the famous ruins of the Roman-Byzantine metropolis and port city of Caesarea.
Beach sand, sand sheets, a linear and transverse dune, and parabolic and transverse interdunes along 2 transects were sampled down to their substrate. Twenty-four samples dated by optically stimulated luminescence (OSL) cluster into three main age groups indicating times of sand deposition; about 5.9–3.3 ka, 1.2–1.1 ka (800–1000 AD) and 190–120 years ago (1825-1895 AD). The 5.9–3.3 ka age group along with previous studies indicates that beach sand started to accumulate substantially when rates of global sea level rise largely declined around 6–5 ka. Until about 4 ka, when local sea level almost reached its present level, sand sheets intermittently encroached up to 2.5 km inland.
Historical and archaeological evidence points to sand mobilization since the first millennium AD while sand sheet ages in the range of 1.2–1.1 ka, coevally found throughout the current dunefield represent sand stabilization probably due to vegetation reestablishment. The stabilization is attributed to gradual and fluctuating decline in human activity from the middle Early Islamic period until the 10-11th centuries. Historical and chronological evidence of the existence of dunes from the early 19th century suggest that the transverse and coppice dune morphologies were probably present only in the last few centuries.
The study illustrates the initial role of natural processes, in this case mainly the middle Holocene decline in sea level rise rates and the primary and later role of fluctuating past human environments upon Holocene coastal sand and dune mobilizations and stabilizations. The study emphasizes distinctions between sand sheets and dunes and portrays the importance of sand bodies as sensors of changes in past and present human environments. The results also exemplify the role of OSL in identifying deposition and stabilization phases in time transgressive sands.

Detailed stratigraphic analysis and numerical dating (OSL, IRSL, ESR, 14C) of Pleistocene coversands in
southwest France enable the construction of a renewed chronostratigraphic framework for sand deposition.
The chronological data obtained from sandsheet units testify to the development of transgressive
dunefields since at least the Middle Pleistocene (MIS 10). Three main phases of accumulation occurred
during the Last Glacial. The oldest one (64e42 ka) is associated with wet sandsheet facies, histic horizons
and zibar-type dune fields, which reflect deposition in a context strongly influenced by the groundwater
table. The Late Pleniglacial (24e14 ka) corresponds to the main phase of coversand extension in a drier
context. Silty gley horizons suggest, however, local interruptions of sand drifting during GS 2.1. Lateglacial
stabilization of the coversands may not have occurred before GI-1c (Allerød), which was typified
by the development of cumulic arenosols. These were covered by parabolic dunes during the Younger
Dryas. The variations in extent of the emerged continental shelf during the glacialeinterglacial cycles
may explain the uneven geographical distribution of sand deposition through time. Because of coastline
retreat up to 100 km north of 45
N during the LGM lowstand, the coversands were unable to reach the
northern part of the basin. Comparison with other European regions highlights stronger affinities of the
French record with Portugal than with the Netherlands and Great Britain, probably because of reduced
influence of permafrost.

The study of active and stabilized late Quaternary aeolian landforms provides important proxies for past climate events and environmental transitions. Despite an overall increase in the study of aeolian landforms in previously glaciated and coastal settings in eastern North America, the history of aeolian sedimentation in many unglaciated inland alluvial settings remain poorly understood. This study reports on the geochronology and depositional history of aeolian landforms and sediments in the unglaciated upper Ohio Valley at the Sandy Springs site. Aeolian landforms and sediments include complex, linear, barchan-like, and climbing dunes; an interdune sand sheet; and sandy loess that blankets high valley surfaces. At Sandy Springs, aeolian dune sands and sandy loess are restricted to intermediate (S2) and higher (S3) geomorphic surfaces. Eight optically stimulated luminescence age estimates constrain the initiation of aeolian processes on the S2 surface to sometime after 17 ka and episodic deposition on the S2 and S3 surfaces between 11 and 1.4 ka. The distribution of aeolian sediments at Sandy Springs is influenced by several past factors including local wind fetch potential, sediment availability, and underlying alluvial topography. Sediment availability is interpreted as the primary factor controlling aeolian processes and appear linked to several pan-regional paleoclimate events. Sandy loess deposition at ca. 8.2 ka on the S3 surface may reflect hydrologic variability and cooling, associated with the final pulse of meltwater into the North Atlantic from the Laurentide Ice Sheet. Dune reactivation and erosion at ca. 4.5 ka on the S2 surface indicate enhanced sediment availability possibly associated with drought conditions. These results illustrate that the deciphering the coupled fluvial-aeolian records in this catchment of the Ohio River provides new insight into the nature of changing surface processes against the backdrop of climate variability over the past ca. 20 ka.

ABSTRACT  This study identifies anthropogenically disturbed areas and barren playa surfaces as the two primary dust source types that repeatedly contribute to dust storm events in the eastern Great Basin of western Utah, U.S.A. This semi-arid desert region is an important contributor to dust production in North America, with this study being the first to specifically identify and characterize regional dust sources. From 2004 to 2010, a total of 51 dust event days (DEDs) affected the air quality in Salt Lake City, UT. MODIS satellite imagery during 16 of these DEDs was analyzed to identify dust plumes, and assess the characteristics of dust source areas. A total of 168 plumes were identified, and showed mobilization of dust from Quaternary deposits located within the Bonneville Basin. This analysis identifies 4 major and 5 secondary source areas for dust in this region, which pro- duce dust primarily during the spring and fall months and during moderate or greater drought conditions, with a Palmer Drought Index (PDI) of −2 or less. The largest number of observed dust plumes (~60% of all plumes) originated from playas (ephemeral lakes) and are classified as barren land cover with a silty clay soil sediment surface. Playa surfaces in this region undergo numerous recurrent anthropogenic disturbances, including mili- tary operations and anthropogenic water withdrawal. Anthropogenic disturbance is necessary to produce dust from the vegetated landscape in the eastern Great Basin, as evidenced by the new dust source active from 2008 to 2010 in the area burned by the 2007 Milford Flat Fire; this fire was the largest in Utah's history due to extensive cover of invasive cheatgrass (Bromus tectorum) along with drought conditions. However, dust mobili- zation from the Milford Flat Burned Area was limited to regions that had been significantly disturbed by post-fire land management techniques that consisted of seeding, followed by chaining or tilling of the soil. Dust storms in the eastern Great Basin negatively impact air quality and transportation in the populated regions of Utah; this study details an improved forecasting protocol for dust storm events that will benefit transportation planning and improve public health.

The Nahal Oz Reservoirin the coastal, semi-arid southwestern Israel was designed to enhance local irrigation of crops using reclaimed sewage water during the dry summer months. On March 2001, part of the western dike of the reservoir was breached and generated a flow release of 3.5 * 10 6 m 3 of secondary irrigation water that was channeled down the 1st order ephemeral loess stream (Nahal Yare'akh). The consequent 12-hour flood surge, with an estimated peak discharge of 1000 m 3 s −1 , inflicted severe loess erosion, agricultural, property and infrastructural damage downstream ($6 million). Post-flood mapping documented the geomorphic response to the flood which included channel scour and widening along the initial 2 km downstream of the reservoir where a spillway channel was formed. The increase in the crosssectional area was about 60% and had an estimated 170,000 m 3 of sediment bed, bank and floodplain erosion. Calculated maximum shear stress and stream power along this section are estimated at 300 Nm −2 and 900 wm −2 , respectively. The peak discharge at the end of this segment was estimated at 800 m 3 s −1 indicating only minor attenuation along this segment. Two km downstream of the breach, a wide braided fan indicated deposition of the eroded sediments. At the end of this segment the floodwater diverged into several watercourses and inundated tilled agricultural fields and neighborhoods. Downstream, 9 km from the reservoir, the discharge attenuated to 100 m 3 s −1 , slightly above bankfull. Further downstream and upon reaching the large Shikma stream the flow was already very low. This reduction in discharge is attributed to the anthropogenic infrastructureroads, neighborhoods and agricultural fields and the large transmission losses typical of sandy ephemeral streams. The study shows that channels within erodible materials respond to high peak discharges very locally. Erosional thresholds that severely incised the channel are only maintained for 2 km below the breached reservoir and as distance from the source area increases, available energy is substantially reduced due to high transmission losses, gentler valley gradients, very wide shallow flow and the ability of the drainage network to accommodate large discharges. Consequently, the geomorphic impact was limited to the first 2.6 km with only minor erosional or depositional evidence downstream. The current natural flow regime has only minor impact on the newly formed channel geometry below the breached dam. Accordingly, the channel geometry may be preserved for a relatively long time. However, channel recovery in this segment was rapid and within a few years all bare loess surfaces exposed during the flood have been covered by dense vegetation. The analysis also shows that Nahal Oz Reservoir's dam-break flood transmission losses and flood attenuation rates were extreme in comparison to other case studies. This artificial flood event in a desert environment offers a rare opportunity to quantify channel and bank erosion evolution processes during an extremely high-magnitude flood within highly erodible fine sediment as well as to detect the recovery processes a few years later.

Using ground-penetrating radar, optically stimulated luminescence dating,
particle-size distribution and morphological analysis, the study of the construction
phases of a vegetated linear dune in the arid north-western Negev
dunefield of Israel during the last millennium improves current knowledge
about vegetated linear dunes that developed in the late Pleistocene. Vertical
accretion in rapid pulses forming horizontally bedded units along the axis of
vegetated linear dunes, regardless of their age, was found to be characteristic
of vegetated linear dunes. The combination of the unique topographic feature
of a longitudinal 5 m step-like fall in dune crest elevation with the substantial
narrowing of dune width constitutes a distinct morphological marker for interpreting
local dune growth and stabilization of the last, albeit localized, dune
mobilization episode at ca 0
5 ka. Evidence for lateral dune migration was not
observed. Where local sediment supply exists, short episodes of powerful
winds within the Holocene (with recurrence intervals separated by hundreds
of years) can lead to the construction of vegetated linear dunes. The spatially
constrained extent of such young dunes in the north-western Negev may be
due to limited sand availability because most of the Negev dunes were stable
during the Holocene. These findings imply that vegetated linear dune construction
can occur in glacial and interglacial (including Holocene) environments
in semi-arid to arid climates if certain conditions are met. In times of
increased wind power during the Anthropocene, a period characterized by
simultaneous rises in the human impact on the landscape and in climate variability
(i.e. drought), local growth of vegetated linear dunes can be expected.
This study demonstrates that ground-penetrating radar is a reliable tool

A B S T R A C T Large amounts of mineral dust are exported from North Africa across the Atlantic Ocean, impacting the atmosphere and ocean during transport and after deposition through biogeochemical processes. In order to characterize the isotopic signature of dust from different seasons and years, in relation to their bulk particle size, and to obtain a general idea of its provenance, Saharan dust was collected using subsurface sediment traps moored in the tropical North Atlantic Ocean in 2012–2013, and by shipboard aerosol collection during three transAtlantic research cruises in 2005, 2012 and 2015. The samples were analysed for radiogenic Strontium (Sr), Neodymium (Nd), and Hafnium (Hf) isotopes, rare earth element (REE; La-Lu) abundances and particle size. In addition, soil sediments from Mauritania, a potential source area, were analysed and compared to the Atlantic dust samples. The results indicate no relation between Sr and Nd isotopic compositions and dust particle size. In contrast, Hf isotopic compositions show a strong relation with particle size, associated to the so-called zircon effect. We explored alternative sources of lithogenic particles to the sediment traps such as Amazon River sediments. Our results reveal that the sediment-trap samples bear distinctly different geochemical signatures from sediments from the Amazon Basin and Amazon River tributaries, and confirm that the primary source of lithogenic particles is northern Africa. The collected dust samples show close relations to African dust aerosols collected at Barbados and samples from the Bodélé Depression, although differences between seasons are observed, which we relate to differences in source areas.

Gypsum (CaSO 4 Á2H 2 O) has been identified as a major component of part of Olympia Undae in the northern polar region of Mars, along with the mafic minerals more typical of Martian dune fields. The source and age of the gypsum is disputed, with the proposed explanations having vastly different implications for Mars' geological history. Furthermore, the transport of low density gypsum grains relative to and concurrently with denser grains has yet to be investigated in an aeolian setting. To address this knowledge gap, we performed a field study at White Sands National Monument (WSNM) in New Mexico, USA. Although gypsum dominates the bulk of the dune field, a dolomite-rich [CaMg(CO 3) 2 ] transport pathway along the northern border of WSNM provides a suitable analog site to study the transport of gypsum grains relative to the somewhat harder and denser carbonate grains. We collected samples along the stoss slope of a dune and on two coarse-grained ripples at the upwind margin of the dune field where minerals other than gypsum were most common. For comparison, additional samples were taken along the stoss slope of a dune outside the dolomite transport pathway, in the center of the dune field. Visible and near-infrared (VNIR), X-ray powder diffraction (XRD), and Raman analyses of different sample size fractions reveal that dolomite is only prevalent in grains larger than $1 mm. Other minerals, most notably calcite, are also present in smaller quantities among the coarse grains. The abundance of these coarse grains, relative to gypsum grains of the same size, drops off sharply at the upwind margin of the dune field. In contrast , gypsum dominated the finer fraction (<$1 mm) at all sample sites, displaying no spatial variation. Estimates of sediment fluxes indicate that, although mineralogical differentiation of wind-transported grains occurs gradually in creep, the process is much more rapid when winds are strong enough to saltate the P1 mm grains. The observed grain segregation is consistent with the WSNM dune field formative friction velocity (0.39 m/s) proposed by Jerolmack et al. (2011): winds significantly weaker than this value would not lift the large grains into differentiation-inducing saltation, whereas the observed differentiated trend would be obliterated by significantly stronger winds. When applied to Olympia Undae, a similar sediment flux analysis suggests that the strongest winds modeled by the Mars Climate Database (MCD) are consistent with the observed concentration of gypsum at dune crests. Density-driven differentiation in transport should not influence sediment fluxes of finer grains (<1 mm) as strongly on Earth, suggesting that the high ratio of fine gypsum grains to other minerals at WSNM is caused by a relatively high production and/or abrasion rate of gypsum sand. The observed preferential transport of coarse-grained gypsum in the dune field conceals a broader range of coarse-grained minerals present on Alkali Flat, contributing to the problem that mineralogy determined through both remote sensing of dune fields and analysis of dune foresets does not fully represent that of the source regions. Unlike quartz, the concentration of gypsum in WSNM occurs not because it is more resistant to weathering and erosion than other minerals, but rather because it is more readily produced (in the case of finer grains) and transported (in the case of coarser grains) than other minerals present in the region.

Aeolian dunes controlled by regional climate have been formed in many coastal areas of the Mediterranean Sea during the Quaternary. Generally, they are formed under a landward blowing wind, and comprise numerous reworked penecontemporaneous shallow marine carbonate grains. Along the eastern mid-Adriatic Sea late Pleistocene aeolian and alluvial sands occur as isolated patches in karstic depressions on several islands and the Pelješac Peninsula. At most localities the sands consist of a mixture of mostly carbonate rock fragments and siliciclastic material. Higher proportion of shallow marine bioclasts was found only at one locality. The terrestrial material was transported to the coastal area by at least two rivers: palaeo-Cetina and Palaeo-Neretva River, and was subsequently reworked and transported by wind, resulting in aeolian deposition. Sandy units of various thicknesses exhibiting sharp erosional bedding planes and cross-bedding are interpreted as representing aeolian dunes and sand sheets controlled by a complex wind regime. The mineralogical composition at almost all localities indicates near-river flood-plains as the main sand source. Although the area was affected by strong winds blowing landward and parallel to the coast, they significantly deviated due to the local topography produced by the tectonically deformed and karstified carbonate basement. In this way, the late Pleistocene aeolian deposits on the mid-Adriatic islands differ from deposits from most Quaternary Mediterranean coastal aeolian belts, since they contain very small quantities of penecontemporaneous shallow marine carbonate grains and were deposited by winds blowing in varying directions instead of prevailing landward blowing winds.

Pyroclastic density currents represent one of the most destructive hazards associated with explosive volcanism. This destructive nature does not only urge the need for but also prevents the obtainment of in situ measurements of their physical characteristics. The resulting deposits offer, however, evidence of the physics of their sedimentation phase. Deposits of dilute pyroclastic density currents frequently exhibit repeated cycles of deposition and erosion, yielding insights into the turbulent shearing along the ground. The utilization of such field observations can be greatly enhanced by the calibration of physical properties of such flows under well-constrained laboratory conditions. Here, wind tunnel measurements were performed using pyroclastic particles. The saltation threshold and surface roughness length were calculated for wind above a pyroclastic bed. The results serve as an aid in linking field observations to quantitative values of turbulent shear at the base of a flow. Scoria and pumice particles were investigated as a function of grain size (1 ϕ fractions between 0.125 and 4 mm), as well as the influence of bedslope (−20°to +25°in 10°steps). The results point to the dominant control of density, grain size and, contrary to previous assumptions, differ moderately from results obtained for round beads. Properly utilized, the dataset enables the establishment of a link between the grain size of natural deposits and the shearing extant during their emplacement. Depending on the type of sedimentary structure observed in the field, the saltation threshold can be used as a minimal or a maximal shearing limit during emplacement of dilute pyroclastic density current deposits. Stoss-aggrading laminations likely involve the saltation threshold as an upper limit, whereas for truncation events it must have been overcome. The effect of particle concentration within the flow, a critical parameter for pyroclastic density currents and the extent of validity of the data, are discussed.

The White Sands Dune Field, New Mexico (USA), provides a unique opportunity to study sources and eolian transport of sand. End member mixing analysis provides unbiased correlation of the grain size distributions of populations that mix sands from four different local source surface types. Textural differences between sources allow local transport paths to be deduced. In total, 1214 surface samples from 10 dunes and 2 downwind-oriented transects were collected. Neither elevation on the dune, lee or stoss location nor distance downwind correlated with mean grain size, coarsest 10% (D 90), or sorting. Instead, grain size distributions are controlled by mixing of locally sourced sand populations. Adjacent dunes can have different mean grain sizes, resulting from different local source populations. Local within-dune and between-dune variability resulting from different sand sources dominates any larger-scale trends across and within dunes. Four sand populations are identified, based on microscopically observable differences in grain size, shape and angularity. Each correlates with high loading of a different statistical factor, derived from End Member Mixing Analysis. End Member 1 (EM1) correlates with well-sorted populations of finer-grained, equant, rounded sands. EM2 correlates with samples that contain moderately sorted populations containing angular blades and crystal aggregates associated with erosional interdunes. EM3 is associated with samples of moderately to poorly sorted fine-grained sand containing fine sand-sized gypsum needles collected from areas of vegetated interdunes, and EM4 is associated with moderately well sorted coarse-and very coarse-grained sands collected from granule ripples. These results suggest that downwind mixing of different populations and segregation by different depositional processes influence grain size distributions in the dune field, rather than by dune-scale or erg-scale transport and sorting.

This paper explores historical evolution of blowouts at Cape Cod National Seashore (CCNS), USA — a site that
hosts one of the world's highest densities of active and stabilized blowouts. The Spatial–Temporal Analysis of
Moving Polygons (STAMP) method is applied to a multi-decadal dataset of aerial photography and LiDAR to
extract patterns of two-dimensional movement andmorphometric changes in erosional deflation basins and depositional
lobes. Blowout development in CCNS is characterized by several geometric (overlap) and movement
(proximity) responses, including: i) generation and disappearance, ii) extension and contraction, iii) union or
division, iv) clustering and v) divergence by stabilization. Other possible movement events include migration,
amalgamation and proximal stabilization, but they were not observed in this study. Generation events were
more frequent than disappearance events; the former were highest between 1985 and 1994, while the latter
were highest between 2000 and 2005. High rates of areal change in erosional basins occurred between 1998
and 2000 (+3932 m2 a−1), the lowest rate (+333 m2 a−1) between 2005 and 2009, and the maximum rate
(+4589 m2 a−1) between 2009 and 2011. Union events occurred mostly in recent years (2000–2012), while
only one division was observed earlier (1985–1994). Net areal changes of lobes showed gradual growth from a
period of contraction (−1119 m2 a−1) between 1998 and 2000 to rapid extension (+2030 m2 a−1) by 2010,
which is roughly concurrent with rapid growth of erosional basins between 2005 and 2009. Blowouts extended
radially in this multi-modal wind regime and, despite odd shapes initially, they became simpler in form (more
circular) and larger over time. Net extension of erosional basins was toward ESE (109°) while depositional
lobes extended SSE (147°). Lobes were aligned with the strongest (winter) sand drift vector although their
magnitude of areal extension was only 33% that of the basins. These differences in extension responses likely
result from more complex and evolving flow-form interactions inside erosional basins. Historical photographs
and CCNS documents suggest that blowout evolution may be influenced by land-use changes, such as revegetation
campaigns in 1985 that were followed by high blowout generation. High magnitude regional storm events
(e.g., hurricanes) also play a role. The analytical framework presented provides a systematic means for twodimensional
geomorphic change detection and pattern analysis that can be applied to other landscapes.

High spatial resolution U^Pb dates of zircons from two consanguineous ignimbrites of contrasting composition, the high-silica rhyolitic Toconao and the overlying dacitic Atana ignimbrites, erupted from La Pacana caldera, north Chile, are presented in this study. Zircons from Atana and Toconao pumice clasts yield apparent 238 U/ 206 Pb ages of 4.11 þ 0.20 Ma and 4.65 þ 0.13 Ma (2c), respectively. These data combined with previously published geochemical and stratigraphic data, reveal that the two ignimbrites were erupted from a stratified magma chamber. The Atana zircon U^Pb ages closely agree with the eruption age of Atana previously determined by K^Ar dating (V4.0 þ 0.1 Ma) and do not support long ( s 1 Ma) residence times. Xenocrystic zircons were found only in the Toconao bulk ignimbrite, which were probably entrained during eruption and transport. Apparent 238 U/ 206 Pb zircon ages of V13 Ma in these xenocrysts provide the first evidence that the onset of felsic magmatism within the Altiplano^Puna ignimbrite province occurred approximately 3 Myr earlier than previously documented. ß

Recent research on quasi-instantaneous turbulent kinematic Reynolds stresses (RS, − u′w′) and decomposed quadrant event activity (e.g., ejections and sweeps) over dunes in fluvial settings and in wind tunnels has shown that turbulent stresses at the toe of a dune often exceed time-averaged, streamwise shear stress (ρ u * 2 ) estimates. It is believed that semi-coherent turbulent structures are conveyed toward the bed along concave streamlines in this region and that impact of these structures cause fluctuations in local surface stresses that assist in grain entrainment. This has been hypothesized to explain how sand is supplied to the windward slope through a region of flow stagnation. Toward the crest, surface stress increases and becomes dominated by streamwise accelerations resulting from streamline compression and convexity that suppress vertical motions. High-frequency (32 Hz) measurements of turbulent wind flow from 3-D ultrasonic anemometers are analyzed for oblique onshore flow over a vegetated coastal foredune in Prince Edward Island, Canada. Reynolds stress and quadrant activity distributions varied with height (0.60 m and 1.66 m) and location over the dune. In general, quadrant 2 ejection (u′ b 0, w′ > 0) and quadrant 4 sweep activity (u′ >0, w′ b 0) dominated momentum transfer and RS generation over quadrant 1 outward interaction (u′ >0, w′ > 0) and quadrant 3 inward interaction (u′ b 0, w′ b 0) activity. On the lower stoss slope, significant ejection and sweep event activity was most frequent (85 to 92%, ejections plus sweeps), whereas, at the upper crest, significant ejection and sweep activity became less frequent while significant outward and inward interactions increased in frequency (25 to 36%). An 'exuberance effect' (i.e., changing shape of quadrant frequency distribution skewed toward ejection and sweep activity) is observed whereby streamline compression and convexity effects inhibit vertical fluctuations in flow and, thus, reduce the frequency of ejections and sweep activity toward the crest. In separated flow in the lee of the crest, quadrant distributions were more symmetrical as a result of more mixed, multi-directional flow. These trends in turbulent event distributions and Reynolds stress have implications for sediment transport dynamics across the dune and may help to explain sand transport potential and dune maintenance. For example, areas with a high frequency of ejection and sweep activity may have higher rates of sediment entrainment and transport, whereas areas with lower ejection and sweep activity and an increase in outward and inward interactions, which contribute negatively to Reynolds stress generation, may experience a greater potential for deposition. Further research on associations between quadrant event activity and coincident sand transport is required to confirm this hypothesis and the resultant significance of the flow exuberance effect in aeolian dune morphodynamics.

Loess is common in the Mid-Atlantic region of the United States south of the Late Wisconsinan glacial border particularly along rivers draining the glaciated areas of Pennsylvania, New Jersey, and New York. The broadest deposits occur on the flat landscapes of the Delmarva Peninsula in Maryland where two episodes of deposition have been identified. The earlier Miles Point Loess has a limited distribution and is buried by the more widespread Paw Paw Loess. OSL and 14C dates place deposition of the Miles Point Loess during MIS 3. The well developed paleosol formed in the Miles Point Loess acts as a stratigraphic marker. The Paw Paw Loess buries Clovis age cultural materials which date deposition to the end of the Pleistocene. Loess deposits and paleosols are critical in understanding regional landscape evolution, Late Pleistocene environments, and early North American cultural history. Mapping the extent of loess in the Mid-Atlantic using the Natural Resources Conservation Service's gSSURGO database overrepresents loess in some areas and underrepresents in others.

CITATIONS 16 READS 109 2 authors: Some of the authors of this publication are also working on these related projects: Project: "Sedimentology and geochemistry of shales and carbonates of the Pilmatué Member, Agrio Formation, Neuquén Basin" View project

A B S T R A C T Dunefields are very common in the northern coastal zone of northeast Brazil. They have the potential to yield important information about paleoclimate, paleo-winds and regional winds and their response to sea-level fluctuations during the Holocene. We reconstructed the coastal dunes geochronological evolution of northwest Ceará State – Brazil, in the last 3000 cal yrs BP, using detailed analyses of lithostratigraphy, microfossil (for-aminifera), wind regime, dune monitoring and 8 radiocarbon dates. The chronology was based on 14 C dating in eolianites and monitoring transversal mobile dunes movement processes. Radiocarbon date results indicated that the dunes corresponding to eolianites revealed ages between 2760–2480 and 980–750 cal yrs BP, suggesting that the vast transversal mobile dunefields were formed after this period in similar condition to the current sea-level. We considered that the material transportation by the prevailing east winds towards the transversal dunes is estimated in the order of 11.0 m/year, thus the current aeolian system is less than 1000 yrs BP.

This paper describes a sensor for measuring the mass flux of aeolian sand transport based on a low-cost piezo-electric transducer. The device is able to measure time series of aeolian sand transport. Maximum fluxes of 27 mg per second can be achieved. The design includes a sand trap, an electronic amplifier circuit and an embedded system for data collection. A field test was performed, where the basis for signal interpretation and the corresponding measurements of aeolian sand transport are presented. The sensor successfully measures fluxes driven by sea breezes of 10 m s −1 , showing the importance of this process for dune-building in the region.

A rapid assessment of burial age for sedimentary materials is useful to aid in-situ interpretation of sites and sequences during fieldwork. This can assist with targeted field sampling strategies for full dating back in the laboratory, for example when the study is concerned with reconstructing landscape dynamics during a specific time period. Field-based  luminescence measurements are possible using a portable luminescence reader; the challenge is translating relative portable luminescence reader signal intensities of samples into an estimate of age. This study uses a portable luminescence reader for the first time in the analysis of African dunefield sediments. Samples from the Namib Sand Sea (NSS) with established luminescence ages are used to assess what in-situ information about relative sample age can be gleamed at and between sites using the portable luminescence reader, and to establish whether first-order estimates of sample age can be obtained. Two sites in the NSS, which are of modern, very late Holocene and last interglacial age were selected for this assessment and a simple calibration between portable luminescence reader signals and sample age is made. Results show that portable luminescence reader signals differ by over two orders of magnitude between late Holocene and last interglacial age samples and that useful relative-age information can be established using bulk material in the field. Predicted ages from portable luminescence reader signals using a linear regression appear to be indicative and useful. Further development of this calibration using a wider range of sample ages would confirm its applicability in the NSS, and a similar approach is applicable to other sand sea environments.

The Dawlish Sandstone Formation is a Late Permian succession of mixed aeolian and¯uvial deposits in the Wessex Basin (SW England). It is used to illustrate two contrasting types of¯uvial/aeolian bounding surface (planar and incised). Planar bounding surfaces separate tabular bodies of¯uvial conglomerate and aeolian dune sandstone. They were produced primarily by wind scour to groundwater table, with the later emplacement of conglomerates resulting in local¯uvial erosion of cemented aeolian dune sandstones. Incised bounding surfaces were produced by¯uvial downcutting. The erosive relief was in®lled with mixed aeolian/¯uvial deposits. The Dawlish Sandstone Formation may provide the ®rst outcrop example of these incised valley ®lls, which have recently been identi®ed as a major component of the subsurface Rotliegend in the Southern North Sea Basin. The potential variability of aeolian/¯uvial sedimentary architecture has important implications for well-to-well correlation and reservoir modelling. q

Infra-red stimulated luminescence (IRSL) dating has been applied to potassium-rich feldspars separated from aeolian sands from seven sites in Lapland. A single aliquot additive dose procedure has been used to show that the sands were well bleached at deposition, despite the high latitudes of the sampling sites. The IRSL dates have been compared with independent age control in the form of radiocarbon dates on charcoal from within the same sections and all show good agreement. Independently controlled IRSL ages as young as 500 years show that this method can be accurately applied to geologically recent sediments. The primary phase of dune stabilisation across Lapland has been shown to have occurred later than was previously thought during the Mid-Holocene. The most recent deflation episode occurred during the last 800 years. within the Little Ice Age, and thus may be a climatically controlled event.

Seven Late Archaic sites located in the Western Shore division of the Coastal Plain physiographic province of central and northern Anne Arundel County, Maryland contain strata apparently buried by
aeolian sands. Components typically found buried at these sites are represented by Late Archaic projectile point types such as Brewerton, Poplar Island, Bare Island, and Susquehanna Broadspear. It is postulated that localized climatic conditions prevalent during the drier Sub-Boreal period caused defoliation which allowed soil erosion and, thus, subsequent deposition of wind-blown sediments responsible for site burial. Initial data seem to indicate that individual sites are not buried to a uniform depth, a situation possibly explained by various discrete natural (e.g., trees) and cultural (e.g., hearths) factors which served to control the amount of aeolian deposition. Due to the dynamics of localized dune formation, the same processes responsible for site burial may also result in site deflation. Hence, the question of whether or not these buried cultural deposits are actually found in situ remains unresolved.

Laguna Las Vueltas (LLV) area retains the morphology of a late Pleistocene watershed that was flooded during a mid-Holocene marine transgression. Sediments associated with a paleosol dated at 22,582 cal yr BP reflect subaerial exposure of the area prior to the submergence during the marine transgression. This transgression produced an extensive tidal flat near the mouth of the former LLV watershed by 7,477 cal yr BP. Subsequent decoupling of the Las Vueltas valley from the sea occurred through the growth of a baymouth barrier and a beach-ridge plain to the east. This decoupling turned the lagoon into a pan environment in which subsequent lake-level fluctuations were controlled by climate. A lunette dune developed at the pans in the former lagoon, providing a narrow corridor where humans trapped, killed and processed guanacos as early as 3,402 cal yr BP. Changes in aeolian sedimentation hint at increased aridity during the past 500 years. RESUMEN. Evolución geomorfológica del área de Laguna Las Vueltas (Tierra del Fuego, Argentina) durante el Pleistoceno tardío y Holoceno. El área de Laguna Las Vueltas (LLV) conserva la morfología de una cuenca hídrica del Pleistoceno tardío que fue inundada durante la transgresión marina del Holoceno medio. Los sedimentos asociados con un paleosuelo datado en 22.582 cal yr AP reflejan la exposición subaérea del área con anterioridad a la transgresión marina. Esta transgresión provocó hacia 7.477 cal yr AP una extensa planicie de marea en la zona baja de la cuenca de la LLV. La subsecuente desvinculación del valle de la LLV con el mar ocurrió a partir del desarrollo de una barrera litoral y una planicie de cordones de playa hacia el este. Este desacople convirtió a la albufera en una laguna somera (pan), donde las subsiguientes fluctuaciones de nivel del agua estuvieron controladas por el clima. Una duna de tipo "lunette" se desarrolló en el área de la antigua albufera, dando lugar a un corredor angosto donde los grupos humanos atraparon, mataron y procesaron guanacos desde al menos 3.402 años cal yr AP. Los cambios en la tasa de sedimentación eólica sugieren un incremento de la aridez en los últimos 500 años.

The eolianites, distributed along the northwestern part of Ceará State coast, are formed by arenaceous rock deposits of quartz-bioclastic composition, cemented by calcium carbonate. This unit establishes an unique record of aeolian activity with peculiar features, rare on the brazilian littoral, whose particular characteristics, preserved in its structures and composition, highlight a large potentiality to provide relevant informations about coastal environment conditions at the time of its formation. The lithified character of these deposits has provided its preservation along the time; however, more friable parts have facilitated erosive wind action, contributing for the discontinuity of distribution and morphology of eolianites. The eolianite deposits invariably display outcrops with large scale sedimentary inner structures, mainly plane-parallel and planar cross-strata, although cross-braided and festooned forms are also relatively well represented, besides other less common. The deposits display aeolian abrasion “ruin” morphology and have a high rigidity comparatively to other aeolian deposits. The correlation between them and current active dunes has lead to the interpretation that most of eolianites records are representative of an evolution phase represented by the formation of compound dunes, with parabolic dunes accumulation at the final stage. An important aspect of these deposits is also the presence of ancient human occupation records, represented by man fragments of manufactured lithics tools and fires.

The aim of this paper is to estimate the amount of aeolian dust, tansferred by dry and wet processes, that is deposited to the eleven marine regions of the Mediterranean-Black Sea Marine System (MBMS) and to compare it to the riverine influxes (i.e. suspended and dissolved sediment loads). This research is based on information for aeolian dust deposition at several coastal stations, around the MBMS, following an extended research of the available literature. For data elaboration, processing, and visualization a G.I.S. environment was utilized. The total annual amount of dust input for the whole system has been estimated to 59.9 × 10 6 tonnes, of which 57.2×10 6 tonnes are deposited in the Mediterranean Sea and only 2.7 × 10 6 tonnes in the Black Sea. The contribution of dust input (load), corresponding to 6.2% and 0.8% of the total amount of suspended and dissolved load, for the Mediterranean and Black Sea respectively, reveals the significant role of the aeolian dust inputs to the MBMS marine environment, in particular, at its southern Mediterranean domain.

A hypothesis of aeolian-induced cyclic meandering was developed during the study made for improvement of a deltaic river mouth.
To cite this article: Lustig, TL. Aeolian-induced Cyclic Meandering of an Ephemeral Deltaic River Mouth [online]. In: Third Australian Conference on Coastal and Ocean Engineering, 1977: The Coast, the Ocean and Man, The. Barton, A.C.T.: Institution of Engineers, Australia, 1977: [230]-[236]. Availability: <https://search.informit.com.au/documentSummary;dn=922642558349659;res=IELENG> ISBN: 085825073X. [cited 01 Aug 18].

Des rejets de la laverie minière de Hammam Zriba (Zaghouan, Tunisie) sont mis en
place au cours de l’édification de la digue à fond plat par décantation. Cette zone
est  soumise  souvent  à  des  phénomènes  météorologiques  (tempêtes  de  vent  et/ou
pluie) qui aggravent ces impacts soit par ruissellement des particules minérales via
le réseau hydraulique soit par la déflation éolienne via l’air. Cette étude consiste à
adopter une approche expérimentale pour quantifier le flux d’érosion éolienne, et
évaluer l’impact de la pollution minière sur les zones urbaines. La méthodologie
adoptée consiste en la mise en place de pièges à sable verticaux (type Rosen 1978)
pendant un événement érosif exceptionnel (tempête de vent du 22 mai 2013). Les
flux d’érosion éolienne mesurés varient entre 1,8 et 6,4 kg/mn/m. La validation des
flux d’érosion éolienne montre que les modèles semi-empirique de Zingg (1953) 
et empirique de Bagnold (1941) s’accordent le mieux aux conditions in-situ.

The northwestern (NW) Negev Desert dunefield covering an area of only 1,300 km2, comprises the eastern end of
the northern Sinai Peninsula – NW Negev erg and is probably the most densely dated dune body in the INQUA
Dunes Atlas chronologic database. Over 230 luminescence ages (TL, IRSL, and mainly OSL) and radiocarbon
dates have been retrieved over the past course of 20 years from calcic and sandy palaeosols serving as dune
substrates, sand sheets, vegetated linear dunes (VLDs), fluvial deposits, and archaeological sites. Despite being
from different deposit types and aeolian morphologies, and based on different methodologies, the chronologies
usually show good compatibility. By reviewing and reassessing the significance of the Eastern Mediterranean
INQUA Dunes Atlas chronologies, along with detailed stratigraphic, structural and geomorphologic data and
understandings, the major, and possibly extreme, episodes of aeolian activity and stability are outlined. Repetitive
chronostratigraphic sequences in VLDs indicate that this dune type, at least in the Negev, comprises a reliable
recorder of main dune mobilization periods.
This presentation demonstrates that certain combinations of research finds, using different OSL dating strategies
and other regional and local late Quaternary records and in particular aeolian ones, are required assets for providing
for acceptable local and regional palaeoclimatic interpretations. The distribution of the VLD chronologies points
to rapid mobilization during the Heinrich 1 and Younger Dryas, characterized by powerful winds, though VLDs
also form in late Holocene palaeoenvironments. Time slices illustrate the different sensitivities of the studied
aeolian landforms to the source, availability, and supply of sediment; long- and short-term climate change, local
human-induced environmental changes and also their joint effects, that enable evaluation of aeolian responses to
future environmental and climate changes.

An analysis of LiDAR data for various coastal counties in North Carolina along with areas recently made available in South Carolina have revealed visual evidence for widespread and large-scale (i.e., kilometers long) eolian activity in the Coastal Plain uplands. These generally low-relief geomorphic features include large swaths or ribbons of coalescing parabolic dunes, transverse or nested parabolic dunes, flat blowout regions near the point of dune origin, and hummocky terrain typical of eolian geomorphic features. Although dune topography in the Coastal Plain has been recognized and mapped prior to the development of LiDAR, these deposits appear to represent an under-recognized or at least under-appreciated geomorphic feature within many areas of the Coastal Plain of North and South Carolina. Eolian features appear associated with dominant westerly winds within flat upland regions of the Coastal Plain and often originate from incised upland terraces and incised headwater regions of small upland feeder streams. As such, eolian deposition may be linked to periods of downcutting and fluvial incision-providing a sand source for eolian remobilization downwind of incised terraces and streams. These dunes, although likely Pleistocene in origin, have implications for archaeological sites in the Coastal Plain uplands where limited Holocene reworking of a plentiful sand source may have contributed to site burial and preservation. Future work should focus on ground truthing these features to verify an eolian origin along with the application of luminescence (OSL) dating to determine the timing of eolian events and linkages to regional paleoclimate data.