Holocene Aeolian Activity Research Articles

Evidence for Holocene Aeolian Activity at the Close of the Middle Bronze Age in the Eastern Carpathian Basin: Geoarchaeological Results from the Mureş River Valley, Romania

While extensive Pleistocene loess deposits have been identified across Eurasia, Holocene age loess (typically nonglaciogenic) is rarely recognized. We explore possible loess deposits in the Mureş River Valley of western Romania, providing a regional signal of increased aridity during the mid‐late Holocene. This proposed aridity may be responsible for the abandonment of Middle Bronze Age tell settlements along the major drainages of the eastern Carpathian Basin (Pannonian plain). This hypothesis centers on a proposed aeolian deposit (the “Pecica deposit”), a ca. 50–80 cm thick, relatively homogeneous, gray layer blanketing the top of the Bronze Age tell of Pecica—Şanţul Mare. Comparing the morphological, geochemical, and physical characteristics of this specific tell deposit with two representative profiles near the site containing glaciogenic calcareous loess and potential Holocene loess deposits developed in Chernozems, we find significant similarities to support this hypothesis. We then review various forms of proxy data published from elsewhere in Central and Eastern Europe suggesting a warming trend during this period. The temporal placement of the Pecica deposit is bracketed using diagnostic artifacts, radiocarbon dates, and the degree of soil development, suggesting a period of increased aridity likely occurring soon after the 17th century B.C.

Holocene aeolian sand mobilization, vegetation history and human impact on the stabilized sand dune area of the southern Nyírség, Hungary

Almost 20% of the territory of Hungary is covered by stabilized dunes formed during the Pleistocene. With the climate amelioration during the early Holocene the aeolian activity ceased. However, various environmental and anthropogenic factors could have reactivated the aeolian processes. Today, there is an increasing climatic stress on the dune fields of the Carpathian Basin, which is coupled with inadequate land use. It is therefore necessary to determine the timing and circumstances of sand mobilization during the Holocene. The site of the present study is located in a dune–interdune system on the southern part of the Nyírség alluvial fan, where periods of Holocene aeolian activity and environmental change were investigated using palynological and sedimentological methods, optically stimulated luminescence and radiocarbon dating. The data achieved show climate-driven Boreal aeolian activity at approximately 8.2ka, and also demonstrate for the first time that during the Atlantic Phase (6.4 and 5.3ka), in spite of the relatively humid climate and dense vegetation, aeolian activity has taken place, induced probably by agricultural practices. Following Subboreal morphological stability, aeolian activity occurred several times in the Subatlantic Phase (2.4–2.2, 1.2–0.8 and 0.4–0.1ka) as a result of vegetation changes and human activity.

Wood charcoal from an inland dune complex at Joldelund (Northern Germany). Information on Holocene vegetation and landscape changes

The charcoal content of an inland dune complex close to Joldelund in Northern Germany was analysed as part of a project which aims to reconstruct Holocene aeolian activity in high spatial and temporal resolution. The eleven investigated profiles contained numerous charcoal-enriched layers, providing evidence for the potential of inland dunes as palaeoarchives for anthracology. Earlier studies have found Late Roman Iron Age settlement activity and iron ore productions in the research area and in its vicinity. Charcoal assemblages date to Roman Iron Age as well as Early, High and Late Medieval Times, according to radiocarbon dating of single, species-identified charcoal fragments and the stratigraphic correlation of sedimentary units. The dominance of Quercus (oak) and significant proportions of Ericaceae-charcoal (probably Calluna vulgaris, heather) especially in the Early and High Medieval samples indicate the presence of a heathland with Quercus trees, which was managed by fire. In the younger layers of sand, a greater diversity of taxa were found, including the dominant Quercus, Fagus (beech), Alnus (alder), Betula (birch), Corylus (hazel), Fraxinus (ash), Salix (willow), Populus-Salix (poplar-willow-type), Acer (maple), Pinus (pine), Maloideae (apple subfamily), Tilia (lime), as well as some Ericaceae. The diversity of species indicates that some charcoals were transported by wind together with the sand from the surrounding areas, and do not represent the local vegetation on the dunes, but rather a nonspecific regional input. The differences in the charcoal assemblages and thus the possible correlation of aeolian units support the stratigraphic correlation of the sedimentary aeolian units. The comparison with the available pollen data from nearby mires showed a good agreement of the proportions of woody taxa, with only few exceptions.

Late Quaternary eolian sand depositional record for southwestern Kansas: Landscape sensitivity to droughts

Eolian deposits and landforms are ubiquitous in western Kansas, particularly south of the Arkansas River with the presence of a stabilized dune field. Stratigraphic studies and associated optical dating reveal a complex depositional history for this dune field spanning the late Quaternary. The oldest eolian deposits from ca. 16 to 12 ka completely or partially bury high terraces with ages of ca. 16 and 33 ka. It is unknown whether these eolian deposits reflect regional aridity and/or a change in sediment availability with the transition of the Arkansas River from a single channel to a braided system. There is pervasive evidence for episodic eolian erosion and deposition ca. 9.8 to 6.3 ka, generally coincident with loess deposition on upland surfaces [Olson, C.G., Nettleton, W.D., Porter, D.A., Brasher, B.R., 1997. Middle Holocene aeolian activity on the High Plains of west-central Kansas. Holocene, 7(3): 255–261], and thus it is inferred to reflect regional aridity. Sites within the dune field show a sequence of eolian sands and weak buried soils, reflecting either dune migration or sand sheet accretion at ca. 1490, 430, 380–320, 180, and 70 yr ago, which correspond well with continental-scale droughts in the tree-ring record. Eolian sand in the Arkansas River dune field may be derived principally with variability in fluvial activity and in climate during the late Pleistocene to the middle Holocene, with substantial reactivation of eolian systems during decadal-scale drought variability in the past 2000 yr.

Luminescence chronology of fluvial and aeolian deposits in the Russian Altai (Southern Siberia)

Geomorphological investigations in the Russian Altai Mountains provide evidence for the extent and timing of Late Quaternary glaciations and aeolian sediments. Infrared optically stimulated luminescence (IR-OSL) and thermoluminescence (TL) dating of aeolian sediments from the central part of the Russian Altai were carried out on silty and sandy sediments that cover fluvial and glacio-fluvial terraces. Most samples from loess, loess-like sediments and sandy loess taken from different terrace sequences within the Altai Mountains provide IRSL ages suggesting a main aeolian deposition period between 25 and 15 ka. These data are consistent with those from the adjacent Mongolian Altai. Sand and silt layers within moraines yielded IRSL age estimates between 22 and 19 ka and correlate to the ice margins of the Last Glacial Maximum. Aeolian dune sands overlying or neighbouring the loess-like sediments and the fluvial terraces at some places provide evidence for Late Glacial (around 15 ka) and Early Holocene (around 9 ka) aeolian activity. The youngest sand sheets gave deposition ages of about 1.5 ka. These sediments covered graves and are related to overgrazing. They provide evidence for the significant human impact on the environment. Fluvial sediments, including silt and sandy gravel intermingled with charcoal, yielded contradicting radiocarbon and luminescence ages. IRSL age estimates obtained for the silty layers range from 19 to 18 ka and are significantly older than the radiocarbon ages, which gave sub-recent ages between 1170 and 910 BP. These data indicate fluvial sedimentation of debris and mudflows in a period of deforestation and strong soil erosion related to mining activities during the 9th and 10th century.

Late Holocene aeolian activity in the Cimarron River valley of west–central Oklahoma

This investigation uses a multidisciplinary approach including geomorphic surface mapping, soil stratigraphic analysis, radiocarbon dating and optically stimulated luminescence (OSL) dating to investigate the chronology of soil formation and aeolian activation periods recorded in ridge dune deposits as well as the spatial variability of aeolian processes during active aeolian episodes. This study shows that aeolian landforms superimposed on fluvial terraces adjacent to the Cimarron River in southeastern Major County and northwestern Kingfisher County, Oklahoma are the product of distinct late Holocene climatic conditions, in which periods of dune activity are episodic and accumulation of sediments is relatively rapid. Soil-forming processes operated on the stabilized dunes during intervening periods. We also demonstrate that the synthesis of geomorphic techniques, soil stratigraphy, 14C dating and OSL dating can provide complimentary and high-resolution data about aeolian activity in the Southern Plains.

Holocene Eolian Activity in South-central Saskatchewan and the Southern Canadian Prairies*

The chronology and stratigraphy of eolian deposits at two sites in south-central Saskatchewan were studied in order to extend the spatial and temporal record of dune activity on the Canadian prairies. Optical ages document the timing of valley-infilling by sand dunes in the Qu’Appelle River area, and of cliff-top eolian deposition along the South Saskatchewan River. These ages, along with published radiocarbon and optical ages, are used to develop a chronology of eolian activity for south-central Saskatchewan. Optical ages of eolian sands ranging from 5.7 to 0.14 ka (before AD 2000), with intervening paleosols, indicate alternating periods of eolian activity and dune stability during the late Holocene, supported by published radiocarbon ages. Other published radiocarbon ages ranging from 11.3 to 8.4 cal ka BP indicate early Holocene eolian activity. Mid-Holocene ages are predominantly absent from the chronology and this is interpreted as being due to extensive eolian reworking during at least the latter part of the mid-Holocene. The chronology in south-central Saskatchewan is similar to other parts of the southern Canadian prairies. It is likely that preserved mid-Holocene eolian deposits occur within depositional basins in the southern Canadian prairies, and at sites near the southern boreal forest boundary with the prairie ecozone.

Late-Holocene inland dune activity in the UK: a case study from Breckland, East Anglia

Inland dunefields found in Breckland, East Anglia, UK, have previously been correlated with the widespread late-Devensian coversands of the region and a seventeenth-century‘sandflood’ which is known to have inundated the village of Santon Downham. A programme of optically stimulated luminescence and radiocarbon dating undertaken on the dunes at Wangford Warren and Santon Downham reveals that episodic aeolian activity has taken place during the last 7000 years. Five sand depositional phases on Breckland dunes are identified: c. 6500, c. 1600-1100, c. 500, c. 400-335 and c. 200-30 years before present. Between c. 2120 and 1840 years ago and within the period 1100-300 years ago quiescent periods allowed the development of fen peat and soils. Local controlling factors on aeolian activity in Breckland appear to be related to anthropogenic activities and livestock (sheep and rabbits) reducing vegetation cover, and decreased precipitation and sea levels which led to lowering of water tables. Breckland aeolian activity, when compared to the national and subcontinental Holocene aeolian activity record, shows a high level of concordance. The underlying forcing factor for late-Holocene dune activity in the UK and elsewhere in Europe appears to be climatic instability in the North Atlantic, associated with both the‘Little Ice Age’ and previous similar events which led to increased storminess, climatic variability and lower temperatures.

Late-Holocene dune activity linked to hydrological drought, Nebraska Sand Hills, USA

Dunefields of the Great Plains contain stratigraphic records of episodic Holocene aeolian activity, potentially providing a valuable record of climatic change. It has been dif” cult to establish unambiguous links between activity at speci” c sites and regional palaeoclimate, however. Here we demonstrate that widespread late-Holocene aeolian activity in the Nebraska Sand Hills, the largest dune” eld on the Great Plains of North America, occurred during a period of hydrological drought. Aeolian sand sheets are interbedded with peat that accumulated in interdunes throughout much of the Holocene. The youngest of these sand sheets was deposited between 950 and 650 cal. BP, about the same time as the most recent major episode of aeolian activity at upland sites up to 120 km apart. Sand sheets could only have advanced across the interdunes if the local groundwater‘ ow systems that maintain interdune wetlands were temporarily reduced or eliminated by a reduction in recharge. Both reduced recharge and upland aeolian activity are best explained by regional megadrought.

A continuous record of Holocene eolian activity in West Greenland

Eolian landforms are widespread alongside proglacial valley-sandurs in West Greenland and comprise low-relief sand sheets, climbing dunes, and upland loess. Sedimentary facies mainly reflect distance to outwash-source zones and the influence of vegetation cover. The sediments show stratification types typical for poorly to moderately vegetated sand-sheets, alternately laminated silt/peat sequences, and unstratified loess. Twenty-five accelerator mass spectrometry 14C dates provide the basis for the chronostratigraphy of the inland eolian deposits. 14C dates from interstratified sand-sheets suggest that the bulk of eolian sands were deposited prior to 3400 cal yr B.P. and after 550 cal yr B.P. This two-phase formation for the inland dunes most likely reflects local changes in proglacial floodplain development and meltwater rerouting associated with a significant recession of the Greenland ice sheet during the mid Holocene climate optimum. Subsequent floodplain regeneration and renewed sand-sheet formation after 550 cal yr B.P. followed when the ice margin readvanced to its present position. In contrast, atmospheric deposition of regionally derived silt in upland peat mires has been continuous since at least 4750 cal yr B.P. Silt influx data demonstrate a strongly episodic history of the intensity of eolian activity over the past five millennia, which tentatively reflects alternating periods of (winter) aridity associated with the variable incursion of maritime air masses over the interior ice-free areas of West Greenland.

The timing of coversand deposition in northwest Norfolk, UK: a cautionary tale

Coversand deposits, consisting largely of reworked fluvial and glaciofluvial sediments, blanket the landscape in discrete areas of northern and eastern England. A newly discovered zone of coversand deposits has been found in northwest Norfolk, which shows stratigraphic evidence of episodic sand accretion. The presence of involutions within the coversand at Leziate signifies the occurrence of post-depositional periglacial activity. Infra-red stimulated luminescence (IRSL) dating of feldspars has been undertaken on five samples from four sites within the new coversand zone. Three of the samples were insufficiently zeroed at deposition to provide accurate dates for deposition of the sand sheets, challenging the assumption that coversands are all well bleached, with consequent implications for existing thermoluminescence (TL) dates on UK coversands. An IRSL age of 12,825±1910 yr for well-bleached sands at Leziate shows that sand accretion occurred during the period of rapid climate transition at the end of the Last Glacial. Late Holocene aeolian activity resulted in sand emplacement at Ling Common.

Holocene aeolian activity in the southwestern Kalahari Desert, southern Africa: significance and relationships to late-Pleistocene dune-building events

Little is known about the timing of dune-building episodes in the southwestern Kalahari Desert. Previously, arid phases when dune activity occurred have been inferred from gaps in chronologies derived from information that attests to former humid periods. To redress this, optically stimulated luminescence (OSL) dating was applied to sediment samples taken from a range of aeolian landforms in the SW Kalahari. Four periods of dune building are identified in the late Pleistocene and Holocene. Holocene aeolian activity at 6 ka and 1-2 ka led to the construction of localised dune forms, in contrast to late Pleistocene times when the extensive field of linear dunes that dominates the region was emplaced. Late-Holocene aridity was however sufficient to allow rapid emplacement of the lunette dune at Witpan. The record of aeolian activity is evaluated in the context of humid chronologies and an ocean-atmosphere model of Holocene climate change, with good agreement obtained. It is concluded that the application of optical dating to a range of aeolian landforms has the potential to establish the style as well as timing of dune-building. It is also demonstrated that the climate during dune-building periods must have differed significantly from the prevailing semi-arid climate with drought periods of today, which may have been the predominant climate regime through much of the Holocene.

Middle Holocene aeolian activity on the High Plains of west-central Kansas

The uppermost surficial stratigraphic unit south of the Arkansas River in the Kansas High Plains is a previously unidentified middle Holocene or younger loess. The unit fits both a loess-thickness and a particle- size model for loess distribution with increasing distance from source. A soil immediately below this unit is radiocarbon dated 6000 to 6700 years BP. The radiocarbon ages indicate that the loess unit is younger than the commonly reported ranges for Bignell Loess in the Great Plains and demonstrate a need for re-examining Holocene loess stratigraphy of the Great Plains. In some locations closest to the Arkansas valley source, this middle Holocene unit is overlain by, or interfingers with, dune sands. The presence of these aeolian sands indicates that, following a period of relative landscape stability and soil development, a shift toward a middle- Holocene climate in which aeolian processes dominated occurred about 6000 years ago on the High Plains of west-central Kansas.

Late Holocene Eolian Activity in the Mineralogically Mature Nebraska Sand Hills

The age of sand dunes in the Nebraska Sand Hills has been controversial, with some investigators suggesting a full-glacial age and others suggesting that they were last active in the late Holocene. New accelerator mass spectrometry radiocarbon ages of unaltered bison bones and organic-rich sediments suggest that eolian sand deposition occurred at least twice in the past 300014C yr B.P. in three widely separated localities and as many as three times in the past 80014C yr at three other localities. These late Holocene episodes of eolian activity are probably the result of droughts more intense than the 1930s “Dust Bowl” period, based on independent Great Plains climate records from lake sediments and tree rings. However, new geochemical data indicate that the Nebraska Sand Hills are mineralogically mature. Eolian sands in Nebraska have lower K-feldspar (and K2O, Rb, and Ba) contents than most possible source sediments and lower K-feldspar contents than dunes of similar age in Colorado. The most likely explanation for mineralogical maturity is reduction of sand-sized K-feldspar to silt-sized particles via ballistic impacts due to strong winds over many cycles of eolian activity. Therefore, dunes of the Nebraska Sand Hills must have had a long history, probably extending over more than one glacial–interglacial cycle, and the potential for reactivation is high, with or without a future greenhouse warming.

Response of eolian geomorphic systems to minor climate change: examples from the southern Californian deserts

Eolian processes and landforms are sensitive to changes in atmospheric parameters and surface conditions that affect sediment supply and mobility. The response of eolian geomorphic systems to minor climate change can be examined through process-response models based on a combination of relations between short-term changes in climatic variables and eolian activity and the geologic and geomorphic record of Holocene eolian activity. At both time scales, eolian activity in southern Californian deserts is strongly controlled by variations in precipitation. Wind energy is not a limiting factor in this region. Formation of eolian deposits is a product of climatic changes that increase sediment supply from fluvial and lacustrine sources and may, therefore, be closely tied to periods of channel cutting and geomorphic instability. During intervening periods, eolian deposits migrate away from sediment source areas and are reworked, modified, and degraded. Remobilization of existing dormant dunes is a product of reduced vegetation cover and soil moisture in periods of drier climates. The major control on these processes is decadal to annual changes in rainfall that determine vegetation cover and soil moisture content.

Holocene eolian activity in the Minot dune field, North Dakota

Stabilized eolian sand is common over much of the Great Plains region of the United States and Canada, including a subhumid area of ~1500 km2near Minot, North Dakota. Eolian landforms consist of sand sheets and northwest-trending parabolic dunes. Dunes and sand sheets in the Minot field are presently stabilized by a cover of prairie grasses or oak woodland. Stratigraphic studies and accelerator mass spectrometry radiocarbon dating of paleosols indicate at least two periods of eolian sand movement in the late Holocene. Pedologic data suggest that all of the dune field has experienced late Holocene dune activity, though not all parts of the dune field may have been active simultaneously. Similar immobile element (Ti, Zr, La, Ce) concentrations support the interpretation that eolian sands are derived from local glaciofluvial and glaciolacustrine sediments. However, glaciolacustrine and glaciofluvial source sediments have high Ca concentrations from carbonate minerals, whereas dune sands are depleted in Ca. Because noneolian-derived soils in the area are calcareous, these data indicate that the Minot dune field may have had extended periods of activity in the Holocene, such that eolian abrasion removed soft carbonate minerals. The southwest-facing parts of some presently stabilized dunes were active during the 1930s drought, but were revegetated during the wetter years of the 1940s. These observations indicate that severe droughts accompanied by high temperatures are the most likely cause of Holocene eolian activity.

Rates, timing, and cyclicity of Holocene eolian activity in north-central United States: Evidence from varved lake sediments

Most of the sediment components that accumulated in Elk Lake, northwestern Minnesota, during the Holocene are autochthonous or biogenic, delivered to the sediment-water interface on a seasonal schedule, preserved in distinct annual laminae (varves). The main allochthonous component is detrital clastic material, as measured by bulk-sediment concentrations of aluminum, sodium, potassium, titanium, and quartz, that enters the lake mostly as eolian dust. The eolian clastic influx to Elk Lake was considerably greater during the mid-Holocene (8–4 ka) than it has been for the past 4000 yr, when periods of increased eolian activity correspond to the time of the Little Ice age and the dust bowl. Geochemical records of eolian activity exhibit distinct cyclicities with dominant periodicities of 400 and 84 yr.

Evidence of holocene aeolian activity in sand dunes from lapland

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.

Thermoluminescence and optically stimulated luminescence dating of Spanish dunes

The second largest expanse of sand dunes and sand sheets in inland Spain is found between the valleys of the Rio Jucar and the Rio Guadiana, to the south of Madrid. The dunes in the Guadiana valley on the San Juan alluvial plain are composed of sands or silty clays. The clay dunes are associated with clay-saline playas to the south and southwest of the town of Alcazar de San Juan. Preserved aeolian landforms indicate a multicyclic origin for the aeolian deposits that overlie Upper Pleistocene alluvial deposits. Both the present day and palaeowind directions are dominantly from the west, northwest and southwest. The results of thermoluminescence and optically stimulated luminescence dating of different samples from these dunes are discussed. The dating results exhibit good agreement between the two luminescence methods for most samples. The dates obtained span the last glacial-interglacial cycle and also indicate Late Holocene aeolian activity.

Estimates of Late Glacial and Holocene aeolian activity in Belgium, Poland and Sweden

A set of textural features is proposed as a measure of the degree of transformation of alluvial source deposits into aeolian ones. Analysis of grain‐size distribution, quartz‐grain rounding and frosting. heavy‐mineral and overall mineral composition and micromorphology of quartz‐grain surfaces in dune and source deposits in Poland. Belgium and Sweden, enabled a variable degree of sediment transformation to be distinguished. The degree of transformation is termed degree of aeolization. It is shown to be dependent upon the total duration of aeolian episodes. The degree of aeolization of the dune deposits investigated is highest in Poland, intermediate in Belgium and lowest in Sweden.