Drift Sand

Large-amplitude meanders may form in low-energy rivers despite generally limited mobility in theses systems. Exceptionally large meanders which even extend beyond the valley sides have developed in the Overijsselse Vecht river (the Netherlands) between ca. 1400 CE (Common Era) and the early 1900s, when channelization occurred. Previous studies have attributed the enhanced lateral dynamics of this river to changes in river regime due to increased discharges, reflecting climate and/or land-use alterations in the catchment. This paper focuses on local aspects that may explain why exceptionally large meanders developed at specific sites. Through an integrated analysis based on archaeological, historical, and geomorphological data along with optically stimulated luminescence dating, we investigated the relative impact of three direct and indirect anthropogenic causes for the local morphological change and enhanced lateral migration rates: (1) lack of strategies to manage fluvial erosion; (2) a strong increase in the number of farmsteads and related intensified local land use from the High Middle Ages onwards; and (3) (human-induced) drift-sand activity directly adjacent to the river bends, causing a change in bank stability. Combined, these factors led locally to meander amplitudes well beyond the valley sides. Lessons learned at this site are relevant for management and restoration of meandering rivers in similar settings elsewhere, particularly in meeting the need to estimate spatial demands of (restored) low-energy fluvial systems and manage bank erosion.

The lithostratigraphy, age and human occupation of the Late Glacial and Holocene aeolian succession of a Late Palaeolithic Ahrensburg site in the excavation Geldrop-A2 (municipality of Heeze-Leende) have been investigated. The exposure revealed a stacked sequence of aeolian sand units and intercalated soils (Older Coversand II, Younger Coversand I (YCI), Usselo Soil, Younger Coversand II (YCII), Holocene podzol, drift sand). Fourteen optically stimulated luminescence dates on quartz and three radiocarbon dates provide the age control of the aeolian deposition (coversands, drift sand), landscape stability (soils) and human occupation. The upper part of the YCI unit was dated to the early Late Glacial. The well-developed Usselo Soil was formed during a phase of landscape stability during the late Allerød interstadial and onset of the Younger Dryas stadial. During the Younger Dryas, low aeolian dunes were formed locally (YCII), as a response to landscape instability due to cooling and ...

Highlights  We detected the anatomical response of exposed roots to gully erosion events.  We used an experimental approach to test the methodological accuracy.  Scars on exposed roots are coincident with changes in wood anatomy.  Exposed root analysis can be used to determine gully erosion rates.

In the Laarder Wasmeren area in the western Netherlands, Late Pleistocene cover sands and overlying early Holocene drift sands show various paleosols, which can be characterized as more or less incipient podzols. We dated those soils and sands by radiocarbon analysis and OSL, and we used biostratigraphical dating based on the known chronology of the vegetation history. Apart from Usselo soils of Allerød age, we found early Holocene soils-showing Usselo soil characteristics but with relatively advanced podzolisation-covered by Early Holocene-early Middle Holocene drift sands. We discuss their age and origin, and reflect on the role of fires and ecosystem degradation in the early development of heathland, podzols and drift sands in the Netherlands, prior to any Neolithic farming. We hypothesize about the possible role of Mesolithic man, stimulating habitats for Corylus avellana by burning pine forest, in the longer term inducing the observed ecosystem degradation (transformation of forest into open short vegetation, acidification and concurrent podzolisation, wind erosion). This hypothesis is in line with studies in adjacent NW-European countries, which are reviewed, and an alternative for the theory of Vera (2000), who assumed that open forests and short vegetation resulted from grazing pressure by large herbivores.

The lithostratigraphy, age and human occupation of the Late Glacial and Holocene aeolian succession of a Late Palaeolithic Ahrensburg site in the excavation Geldrop-A2 (municipality of Heeze-Leende) have been investigated. The exposure revealed a stacked sequence of aeolian sand units and intercalated soils (Older Coversand II, Younger Coversand I (YCI), Usselo Soil, Younger Coversand II (YCII), Holocene podzol, drift sand). Fourteen optically stimulated luminescence dates on quartz and three radiocarbon dates provide the age control of the aeolian deposition (coversands, drift sand), landscape stability (soils) and human occupation. The upper part of the YCI unit was dated to the early Late Glacial. The well-developed Usselo Soil was formed during a phase of landscape stability during the late Allerød interstadial and onset of the Younger Dryas stadial. During the Younger Dryas, low aeolian dunes were formed locally (YCII), as a response to landscape instability due to cooling and ...

Buried soil surfaces are rich sources of information about past fauna, vegetation development, glacier dynamics, and climate variations However, in Denmark such former surfaces are very rare, as they rarely have escaped the intensive erosion below and in front of the Scandinavian ice sheets during the previous cold stages. Here we present a well-drained paleosol found extensively in a large gravel pit in the central part of Jutland, Denmark. The paleosol is suggested denoted the "Asklev paleosol". The Asklev paleosol is a well developed Podzol in sandy till of late Saalian age-the Asklev Till. The Asklev podsol is covered by fluvial sand in which another weaker podsol is present. Thermo-luminescense dating of the sand layer revealed an age of c. 100 ka BP, i.e. that the soil surface was buried in the early Weichelian. The surface was thus stable during the entire Eemain interglacial and subject to pedogenesis for >15.000 years. Discordantly resting on the fluvial sand is about 1.5 m of sandy till with an undisturbed grey lower part and a brown cryoturbated upper part. Fabric analyses from the lower grey part of the till reveal an ice movement from the SSE. This till is deposited during MIS 4 in middle Weichselian Thin sections from the Podzol' show that the buried A-horizons micromorphology is not fully comparable to present-day Podzols in the region as it has a well developed argillic horizon below despite the parent material low in clay (< 3%). In contrast to modern Danish Podzols it also retain ample evidence of burning (charcoal) and frost features (capping). The Asklev paleosol classify as a Placic Podzol, but is a typical bi-sequum with a Bt-horizon at depth. Its content of organic C is up to 38 mg C/g soil in the A-horizon, 8.4 mg C/g soil in the Bhs-horizon, which decreases to <1 mg C/g soil in the C-horizon. Carbon-to-nitrogen ratios range from 80 in the E-horizon to 25 in the C-horizon. Concentrations of heavy metals is low with maximums of 3.7 mg Ni/kg soil, 16.4 mg Cr/kg soil, <0.05 mg Cd/kg soil, 6.7 mg Pb/kg soil and 33 mg Cu/kg soil. Arsenic concentrations vary from <0.1 mg/kg soil in the E-horizon to 4.7 mg/kg soil in the Bt-horizon. Comparing the geochemistry of the Asklev paleosol with a modern analogue Podzol in a nearby natural, ancient woodland reveal a general higher content of heavy metals in the paleosol. These differences reflect a combination of different parent materials, modern-day pollution rates, losses/additions during the c. 90 ka where the soil has experienced permafrost, and the c. 10 ka with moist conditions during the present interglacial. The combined methods together reflect a soil surface from the previous interglacial which may act as an important reference for modern-day soil chemical status and e.g. pollution rates, especially if enough sites with the Asklev paleosol is analysed.

Large-amplitude meanders may form in low-energy rivers despite generally limited mobility in theses systems. Exceptionally large meanders which even extend beyond the valley sides have developed in the Overijsselse Vecht river (the Netherlands) between ca. 1400 CE (Common Era) and the early 1900s, when channelization occurred. Previous studies have attributed the enhanced lateral dynamics of this river to changes in river regime due to increased discharges, reflecting climate and/or land-use alterations in the catchment. This paper focuses on local aspects that may explain why exceptionally large meanders developed at specific sites. Through an integrated analysis based on archaeological, historical, and geomorphological data along with optically stimulated luminescence dating, we investigated the relative impact of three direct and indirect anthropogenic causes for the local morphological change and enhanced lateral migration rates: (1) lack of strategies to manage fluvial erosion;...

The geomorphological analysis of two sections cut into a sandy landscape in northeast Belgium enabled the establishment of a chronology for a sequence of events during the last 15 ka that illustrate the polycyclical nature of the evolution of such landscapes. Field descriptions, analytical sediment and soil characterization, and pollen analysis are combined with the optically stimulated luminescence dating method to unravel the recent geomorphological history of the investigated site. The principal results include apparently discontinuous sand deposition between $15 and 12 ka, landscape stabilization and Podzol formation between $12 and 1 ka, the development of a drift sand landscape between $650 and 200 a, and renewed stabilization over the last two centuries. The results are discussed in the light of climate, land-use and vegetation changes and compared with findings at similar sites in the European Sand Belt.

A study was made of the applicability of three different techniques for equivalent dose (D e) determination in the optical dating of quartz: the single-aliquot regenerative-dose technique (SAR), the single-aliquot additive-dose technique (SAAD) and the multiple-aliquot additive-dose technique (MAAD). For this purpose, quartz grains were extracted from a sequence of Upper Pleniglacial to Late-glacial coversands exposed at the locality of Ossendrecht in the southwestern Netherlands, a site for which both radiocarbon and earlier luminescence dates are available, providing independent age control. Upon testing the different assumptions underlying each of the three OSL techniques investigated, the SAR protocol was found to be the technique of choice. The optical ages obtained with this protocol were in good agreement with the chronostratigraphical position of the sediments investigated and with the available chronostratigraphical information on the same and equivalent deposits. This confirms the suitability of the SAR technique for dating coversands. Furthermore, a small laboratory intercomparison of SAR-based D e determinations yielded results that were in fair overall agreement.

Earlywood, latewood, total ring width and cross-sectional earlywood vessel lumen areas were measured in twenty-one Fraxinus nigra trees located in the southern boreal region of Quebec, Canada. Two of the trees survived a severe fire in 1923 during which year almost no latewood was produced. In 1924 both trees produced rings with a strong decrease in the size of the largest earlywood vessels. This synchronized size decrease in cross-sectional earlywood vessel lumen area was not observed in other years and is likely a response of the trees to either direct injury or changes in environmental conditions associated with fire. Vessel characteristics in ring-porous species have the potential to be used in conjunction with other indicators of fire to extend fire history reconstructions on a spatial scale.

The chronology of polycyclic driftsand sequences in cultural landscapes has mainly been based on the combination of radiocarbon (14 C) dating of intercalated organic horizons and pollen analysis. This approach, however, yields indirect age information for the sediment units. Also, as soils are dynamic systems, the pedogenetical interpretation of the 14 C ages is often quite difficult. To improve the results of radiocarbon dating, we applied fractionated 14 C dating, sustained by soil micromorphology and pyrolysis-gas chromatography/mass spectrometry. The results indicate the complexity of the sources and decomposition processes of SOM, and, consequently, provide information as to why radiocarbon dates are not always reliable for the geochronology of driftsand deposits. We then performed an optically stimulated luminescence (OSL) dating study of the driftsand beds in the sequence. This approach yields direct sedimentation ages, and allows differentiating the instable (sand drifting) period from the stable (soil formation) period in each individual cycle of the sequence. Post-depositional mixing of the sands, however, may upset the reliability of the OSL chronology.

Background and Objectives: Studying responses in woody plants upon water limitation is gaining importance due to the predicted increase in frequency and intensity of droughts in Europe. We studied the variation in radial growth and in wood anatomical traits caused by water limited growth conditions in offspring from Quercus petraea (Matt.) Liebl., Q. robur L. and their morphological intermediates grown in the same environment. Materials and Methods: Cross sections were prepared from the stems of 210 three-year-old potted seedlings, comprising control plants and seedlings that experienced from late spring until early autumn of the first growing season two sequential periods of water with-holding each followed by plentiful re-watering. Pith radius, ring width of the three growing seasons and latewood vessel diameter in second and third growing season were measured. Presence of intra-annual density fluctuations, dendritic patterns of latewood vessels and the level of ring closure of ea...

We performed Q-band ESR spectroscopy on several single quartz grains from different geological deposits. Various properties of Tirelated impurity centres in quartz relevant for ESR dating were studied. It will be shown that some properties, such as sensitivity change and response to artificial g-irradiation, may vary from grain to grain. It is concluded that single grain ESR dating is feasible at a pure experimental level. r

Aims This paper aims to analyze the reliability of exposed roots oriented perpendicular to the slope to quantify sheet erosion rates based on accurate reconstruction of topography using terrestrial laser scanner (TLS). Methods The study was performed in an experimental sandy badland located in Central Spain. Sampling procedures were conducted in three different homogenous hydrological response units (HRU). We derived eroded soil thickness from by obtaining accurate microtopographic data using TLS. In addition, dendrogeomorphic procedures , based on anatomical changes in root rings, were used to determine the first year of exposure of 46 Pinus pinaster roots. Results Results indicate that medium-term (±30 year) erosion rates obtained from roots growing perpendicular to the slope were significantly different from those obtained from exposed roots growing parallel to the slope (p-value <0.05). However, at short term (up to 5 years), result agree with those obtained from erosion pin monitoring at the study site, which confirms the potential of reconstructions based on perpendicular roots. Conclusion The utility of exposed perpendicular roots coupled with accurate eroded soil estimation has been proved. It allows the extension of the applicability of dendrogeomorphic approaches, particularly for ungauged badlands where instrumental data is scarce or completely missing.

Holocene drift-sand activity is commonly linked directly to population pressure and agricultural activity. The first occurrence of small-scale Holocene aeolian activity took place during the Neolithic, whereas large scale drift-sand activity started during the Middle Ages (especially after AD 1100) due to intensification of farming and demographic pressure. Although demographic pressure is widely accepted to be the main cause behind drift-sand activity, this is currently not supported by studies that link spatial and temporal patterns in landscape management and drift sand occurrence on a supra-regional scale. Population size gradually increased from the Neolithic period onwards but was interrupted during the late-Roman period and the beginning of the Early Middle Ages (roughly 4 th-5 th century). This resulted in a regional reforestation phase, probably coinciding with decreased drift-sand dynamics. In this contribution, we compare events of drift-sand activity with locations characterised by intensified demographic pressure on the landscape for three periods: the Roman period, the Early Middle Ages and the Late Middle Ages for characteristic Pleistocene sand regions in the Netherlands. For this, we compiled a new supra-regional overview of drift-sand activity dates (14 C, OSL, archaeological and historical), that we compared with existing national soil maps, historical-route networks and vegetation reconstructions. Here we present the first results of this spatial comparison and assess the relative importance of environmental factors (e.g., landscape setting) and demographic pressure on the formation of drift sands for these periods.

A new site with Lateglacial palaeosols covered by 0.8 - 2.4 m thick aeolian sands is presented. The buried soils were subjected to multidisciplinary analyses (pedology, micromorphology, geochronology, dendrology, palynology, macrofossils). The buried soil cover comprises a catena from relatively dry (‘Nano’-Podzol, Arenosol) via moist (Histic Gleysol, Gleysol) to wet conditions (Histosol). Dry soils are similar to the so-called Usselo soil, as described from sites in NW Europe and central Poland. The buried soil surface covers ca. 3.4 km2. Pollen analyses date this surface into the late Allerød. Due to a possible contamination by younger carbon, radiocarbon dates are too young. OSL dates indicate that the covering by aeolian sands most probably occurred during the Younger Dryas. Botanical analyses enables the reconstruction of a vegetation pattern typical for the late Allerød. Large wooden remains of pine and birch were recorded.

Lavaka represent a typical erosional landform in Madagascar. The chronology of their formation remains, however, under discussion. Our research focuses on the Ankarokaroka lavaka, a spectacular landform located in NW Madagascar (Ankarafantsika natural reserve), which is characterized by the presence of sandy units of regional extension at its top. The two main units correspond to white and red sands, and are closely associated with specific vegetations (dry dense forest for the white sands, savannah grasslands for the red sands). We applied a geochronological approach based on Optically Stimulated Luminescence (for the coversands) associated with radiocarbon dating performed on archaeological remains found at the contact between the sands and the lavaka. The combination of this approach with field work and sedimentological analyses makes it possible to show that the sands experienced a complex history, both in terms of sedimentation and post-sedimentary pedogenesis (podzolization of the white sands, rubefaction of the red sands). The numerical ages furthermore indicate that the Ankarokaroka lavaka formed between 18.5 ± 2.3 ka ago and the 14th century AD. The present study demonstrates that this lavaka has a climatic origin, and highlights the potential of OSL to date sediments associated with Madagascar lavaka.

We present the results of an interdisciplinary study on the human‐induced transformation of a late Holocene landscape on a ca. 6 km² large interfluve between the rivers Kleine Nete and Grote Nete in the Campine area, north‐eastern Belgium. Descriptions of cross‐sections and hand‐drillings, soil profile analyses, palynology, optically stimulated luminescence (OSL) dating, historical archives and GIS‐data were used to establish a chronology of land‐use changes and their impact on the landscape during the last millennium. The first evidence of geomorphological changes in the slightly undulating deforested late Holocene sandy landscape is a thin layer of drift sand dated to between 1200‐1500 AD. It is thought to have been caused by destruction of the heather vegetation due to grazing and perhaps an early form of plaggen agriculture. Between 1500‐1750 AD clear evidence is seen for a strong land‐use intensification, including further destruction of the heather vegetation, wind-enhanced er...

SUMMARY Due to the likelihood of global climate change, the frequency and magni- tude of natural hazards such as mass movements may likewise change, thus favouring the refinement of methods to detect and quantify geomor- phic events when precise records are not available. Geomorphic events typically have a significant effect on tree growth, e.g., reaction wood marked by changes in

In dendrogeomorphology, abrupt changes in wood anatomy are frequently used to date the exact year of burial and exposure events. However, few studies have addressed the precision and underlying mechanisms of these changes. In a field experiment, performed in a drift-sand area in the Netherlands, we buried the stems of mature pedunculate oak trees (Quercus robur L.) up to a height of 50 cm and analysed the responses in ring width and earlywood-vessel characteristics, while monitoring the course of temperature above and below the soil surface.

The geomorphological analysis of two sections cut into a sandy landscape in north-east Belgium enabled the establishment of a chronology for a sequence of events during the last 15 ka that illustrate the polycyclical nature of the evolution of such landscapes. Field descriptions, analytical sediment and soil characterization, and pollen analysis are combined with the optically stimulated luminescence dating method to unravel the recent geomorphological history of the investigated site. The principal results include apparently discontinuous sand deposition between $15 and 12 ka, landscape stabilization and Podzol formation between $12 and 1 ka, the development of a drift sand landscape between $650 and 200 a, and renewed stabilization over the last two centuries. The results are discussed in the light of climate, land-use and vegetation changes and compared with findings at similar sites in the European Sand Belt.

During the Holocene, Late Glacial aeolian deposits throughout the European sand belt were reactivated as sand drifts (e.g. KOSTER 1982; HILGERS 2007; TOLKSDORF and KAISER 2012). The well-documented lack of synchronicity in the temporal and spatial distribution of Holocene dune activity clearly argues against any single major external force as the main trigger of this reactivation process, but rather points towards localised nuclei and human impact (CASTEL 1991; HILGERS 2007; TOLKSDORF and KAISER 2012). In the Netherlands, most sand drifts date from the high to post-medieval period (KOSTER 1978; CASTEL 1991; KOSTER et al. 1993). Their formation was probably connected to an intensification of land use in settlement peripheries (outfields), but contextual evidence for this is scarce (JUNGERIUS and RIKSEN 2010: 66).
In recent years archaeological excavations have produced a growing body of evidence for the existence of prehistoric sand drifts along terraced Dutch river valleys (fig. 1). The archaeological context of these sand drifts strongly suggests that they are (largely) anthropogenic in origin and that they were originally situated in settlement infields. We conclude that early reclamations of dunefields along river valleys had disproportionately large consequences, as they exposed a landscape in a state of incipient instability to erosion and ‘desertification’.