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

2012 ◽  
Vol 78 (3) ◽  
pp. 492-501 ◽  
Author(s):  
Tímea Kiss ◽  
György Sipos ◽  
Barbara Mauz ◽  
Gábor Mezősi

AbstractAlmost 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 8.2 ka, and also demonstrate for the first time that during the Atlantic Phase (6.4 and 5.3 ka), 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 0.4–0.1 ka) as a result of vegetation changes and human activity.

2013 ◽  
Vol 79 (3) ◽  
pp. 403-412 ◽  
Author(s):  
Mingrui Qiang ◽  
Fahu Chen ◽  
Lei Song ◽  
Xingxing Liu ◽  
Mingzhi Li ◽  
...  

AbstractAeolian deposits at four sites in the Gonghe Basin were used to reconstruct the history of aeolian activity over the late Quaternary. These deposits include well-sorted aeolian sand, paleosols and/or loess. Aeolian sand represents dune-field expansion and/or dune buildup, whereas paleosols indicate stabilization of dunes, accompanying ameliorated vegetation cover. On the basis of 25 dates by optically stimulated luminescence (OSL), it appears that aeolian activities occurred episodically at 33.5, 20.3, 13.9, 11.8–11.0, 9.4, 7.8, and 5.7 (5.5) ka, which is largely consistent with the recent findings from the adjacent semi-arid areas. Aeolian sand mobility occurring during the early to mid Holocene conflicts with a climatic optimum inferred from lacustrine records in the northeastern Qinghai-Tibetan Plateau. This inconsistency may be resolved by interpreting aeolian activity as a response to decreased effective moisture due to enhanced evaporation, induced by higher summer insolation at that time, together with local terrain and its effects on moisture. Our results suggest that aeolian sand and paleosol cannot be simply ascribed to regional dry and wet climates, respectively, and they most likely reflect changes in effective moisture.


2015 ◽  
Vol 83 (1) ◽  
pp. 178-186 ◽  
Author(s):  
Markus Fuchs ◽  
Rebecca Reverman ◽  
Lewis A. Owen ◽  
Kurt L. Frankel

AbstractLarge alluvial fans characterize the piedmonts of the White Mountains, California–Nevada, USA, with large boulders strewn across their surfaces. The boulders are interpreted as flash floods deposits with an unclear trigger for the transport process. Several triggers are possible, including glacial lake outburst floods (GLOFs), thunderstorms or rainfall on snow cover. From a paleoenvironmental perspective, the origin of the flash floods is of fundamental importance. The alluvial fans that flank the White Mountains at Leidy Creek display particularly impressive examples of these deposits. The boulder deposits and the source catchment at Leidy Creek were examined using 10Be terrestrial cosmogenic nuclide (TCN) surface exposure dating to help elucidate their age and origin. All boulders dated on the alluvial fans date to the Holocene. This is in accordance with the geomorphic analyses of the Leidy Creek catchment and its terraces and sediment ridges, which were also dated to the Holocene using optically stimulated luminescence (OSL) and 10Be surface exposure. The results suggest that the boulders on the alluvial fan were deposited by flash floods during thunderstorm events affecting the catchment of the Leidy Creek valley. Paleomonsoonal-induced mid-Holocene flash floods are the most plausible explanation for the discharges needed for these boulder aggradations, but a regional dataset is needed to confirm this explanation.


Author(s):  
Philip L. Gibbard ◽  
Mark D. Bateman ◽  
Jane Leathard ◽  
R.G. West

Abstract Previous investigation of isolated landforms, on the eastern margin of the East Anglian Fenland, England, has demonstrated that they represent an ice-marginal delta and alluvial fan complex deposited at the margin of an ice lobe that entered the Fenland during the ‘Tottenhill glaciation’ (termed the ‘Skertchly Line’). They have been attributed, based on regional correlations, to a glaciation during the Late Wolstonian (i.e. Late Saalian) Substage (Drenthe Stadial, early Marine Isotope Stage (MIS) 6). This paper aimed to test this correlation by directly optically luminescence dating, for the first time, sediments found within the Skertchly Line at Shouldham Thorpe, Norfolk, and Maidscross Hill, Suffolk, together with those in associated kame terrace deposits at Watlington, Norfolk. Ages ranged from 244 ± 10 ka to 12.8 ± 0.46 ka, all the results being younger than MIS 8 with some clearly showing the landforms have been subsequently subjected to periglacial processes, particularly during the Late Devensian Substage (∼MIS 2). Most of the remainder fall within the range 169–212 ka and could be assigned to MIS 6, thus confirming the previously proposed age of the glaciation. The local and regional implications of these conclusions are discussed, the maximum ice limit being linked to that of the Amersfoort–Nijmegen glaciotectonic ridge limit in the central Netherlands.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Fernando Gázquez ◽  
Thomas K. Bauska ◽  
Laia Comas-Bru ◽  
Bassam Ghaleb ◽  
José-María Calaforra ◽  
...  

Abstract Carbonate cave deposits (speleothems) have been used widely for paleoclimate reconstructions; however, few studies have examined the utility of other speleothem-forming minerals for this purpose. Here we demonstrate for the first time that stable isotopes (δ17O, δ18O and δD) of structurally-bound gypsum (CaSO4·2H2O) hydration water (GHW) can be used to infer paleoclimate. Specifically, we used a 63 cm-long gypsum stalactite from Sima Blanca Cave to reconstruct the climate history of SE Spain from ~ 800 BCE to ~ 800 CE. The gypsum stalactite indicates wet conditions in the cave and humid climate from ~ 200 BCE to 100 CE, at the time of the Roman Empire apogee in Hispania. From ~ 100 CE to ~ 600 CE, evaporation in the cave increased in response to regional aridification that peaked at ~ 500–600 CE, roughly coinciding with the transition between the Iberian Roman Humid Period and the Migration Period. Our record agrees with most Mediterranean and Iberian paleoclimate archives, demonstrating that stable isotopes of GHW in subaerial gypsum speleothems are a useful tool for paleoclimate reconstructions.


2019 ◽  
Vol 56 (2) ◽  
pp. 175-182
Author(s):  
Timothy G. Fisher ◽  
Jennifer Horton ◽  
Kenneth Lepper ◽  
Henry Loope

The last aeolian activity of a significant number of inland sand dunes in the southern Great Lakes region (SGLR) was several thousands of years after deglaciation. At Mongo, Indiana, a field of parabolic sand dunes with a variety of morphologies are within the channel bottom of the Pigeon River meltwater channel, with some dunes having climbed up the channel wall onto the adjacent upland surface. The optically stimulated luminescence (OSL) samples from the channel-bottom dunes have a mean age of 14.2 ± 1.6 ka (n = 2) and the OSL samples from upland dunes have a mean age of 12.3 ± 1.6 ka (n = 4). Dunes and outwash ages and geomorphic setting constrain both the position of the Huron-Erie and Saginaw lobes. The oldest dune age is also a minimum age for cessation of local meltwater flow from the Huron-Erie Lobe of the Laurentide Ice Sheet and formation of the adjacent Sturgis Moraine of the Saginaw Lobe. The final activity of the dunes is coincident with late glacial stadial and interstadial events as recorded in the Greenland ice core records, a similar finding to all other studies of dunes in the SGLR. It is now well recognized that many dunes were last active before, during, and after the Younger Dryas stadial, presumably in response to a climate that was windier and less favorable for vegetation.


2016 ◽  
Vol 86 (3) ◽  
pp. 260-270 ◽  
Author(s):  
Isabel Lemus-Lauzon ◽  
Najat Bhiry ◽  
James Woollett

AbstractWe reconstructed the late Holocene vegetation of the Nain region (northern Labrador, northeastern Canada) in order to assess the influence of climate and historic land use on past shifts in forest composition. Chronostratigraphy was used in combination with macrofossil and pollen data from monoliths sampled from four peatlands. Paleoecological reconstructions produced a vegetation history spanning 4900 years for the Nain region that is largely concordant with other studies in Labrador. An initial open forest tundra phase was followed by an increase in tree cover at around 2800 cal yr BP. Paludification began ∼200 cal yr BP. A decline in Picea and its subsequent disappearance from most of the sites occurred ∼170 cal yr BP (AD 1780) in a period of relatively mild conditions during the Little Ice Age. This event was followed by the establishment of Larix laricina in the region. Local anthropogenic factors are likely responsible for these later developments, as they were not observed in other regional studies. The period around AD 1780 corresponds to the establishment of the Moravian missionaries on the Labrador coast, which increased the need for fuel and lumber. We conclude that changes in land use are reflected in the patterns of vegetation and hydrological change at the study sites.


2020 ◽  
Vol 21 (3) ◽  
pp. 1076 ◽  
Author(s):  
Bhakti Prinsi ◽  
Osvaldo Failla ◽  
Attilio Scienza ◽  
Luca Espen

Salinity represents a very limiting factor that affects the fertility of agricultural soils. Although grapevine is moderately susceptible to salinity, both natural causes and agricultural practices could worsen the impact of this abiotic stress. A promising possibility to reduce this problem in vineyards is the use of appropriate graft combinations. The responses of grapevine rootstocks to this abiotic stress at the root level still remain poorly investigated. In order to obtain further information on the multifaceted responses induced by salt stress at the biochemical level, in the present work we analyzed the changes that occurred under control and salt conditions in the root proteomes of two grapevine rootstock genotypes, M4 and 101.14. Moreover, we compared the results considering that M4 and 101.14 were previously described to have lower and higher susceptibility to salt stress, respectively. This study highlighted the greater capability of M4 to maintain and adapt energy metabolism (i.e., synthesis of ATP and NAD(P)H) and to sustain the activation of salt-protective mechanisms (i.e., Na sequestration into the vacuole and synthesis of osmoprotectant compounds). Comparitively, in 101.14 the energy metabolism was deeply affected and there was an evident induction of the enzymatic antioxidant system that occurred, pointing to a metabolic scenario typical of a suffering tissue. Overall, this study describes for the first time in grapevine roots some of the more crucial events that characterize positive (M4) or negative (101.14) responses evoked by salt stress conditions.


2006 ◽  
Vol 80 (2) ◽  
pp. 207-212 ◽  
Author(s):  
T. Romig ◽  
D. Thoma ◽  
A.-K. Weible

AbstractTransmission of the fox tapeworm Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, is known to depend on various environmental factors which are subject to human influence. Epidemiological data suggest that in most endemic regions anthropogenic landscape changes (e.g. deforestation and agricultural practices) have led to more favourable conditions for the parasite's animal hosts, especially arvicolid rodents, thereby increasing the risk for parasite transmission and human disease. Examples are the conversion of forests or crop fields into meadows and pastures in Europe, China and North America, and overgrazing of natural grassland in central Asia. Other anthropogenic factors include interference with host population densities by wildlife disease control, changing hunting pressure and provision of new habitats, e.g. in urban areas. Domestic dogs may, under certain conditions, get involved in the otherwise largely wildlife-based transmission, and thereby greatly increase the infection pressure to humans. The introduction of neozootic host species may increase transmission, or even initiate the parasite's life-cycle in previously non-endemic regions. Lastly, the parasite itself may be accidentally introduced into non-endemic areas, if suitable host populations are present (e.g. in northern Japan).


2009 ◽  
Vol 72 (3) ◽  
pp. 431-442 ◽  
Author(s):  
Irene Zembo ◽  
Laura Panzeri ◽  
Anna Galli ◽  
Riccardo Bersezio ◽  
Marco Martini ◽  
...  

AbstractOptically Stimulated Luminescence (OSL) enables the chronology of the late Pleistocene evolution for the Val d'Agri intermontane basin of Southern Apennines to be defined in the frame of Mediterranean geodynamic and climate changes. Quartz sand from braided floodplain and alluvial fan depositional systems was analyzed using the coarse-grained, single-aliquot regenerative-dose (SAR) technique. The obtained optical ages are mostly consistent with other assessments (radiocarbon, tephrochronology) and stratigraphic constraints. OSL allows for the dating to 56–43 ka of an asymmetric subsidence stage that forced alluvial fan progradation, filling of a former lacustrine area, and development of an axial alluvial plain. A short period of Mediterranean-type pedogenesis, recorded at the top of the prograding-aggrading fans (OSL age bracket 43–32 ka), corresponds with MIS 3. During the subsequent stage of decline of vegetation cover, possibly corresponding to MIS 2, the latest progradation of alluvial fans occurred. The subsequent uplift and breakthrough of the basin threshold during the latest Pleistocene and Holocene induced entrenchment of the drainage network. The results presented here provide an example of the usefulness of OSL dating in intermontane continental settings where other geochronological constraints are scarce.


2017 ◽  
Vol 38 (3) ◽  
pp. 265-289 ◽  
Author(s):  
Edyta Kalińska-Nartiša ◽  
Kristaps Lamsters ◽  
Jānis Karušs ◽  
Māris Krievāns ◽  
Agnis Rečs ◽  
...  

Abstract It is assumed that close to the margins of ice-sheets, glacial, fluvial and aeolian processes overlap, and combined with weathering processes, produce numerous sediments, in which quartz is a common mineral. Quartz grains, if available, may serve as a powerful tool in determining the depositional history, transportation mode and postdepositional processes. However, quartz grain studies in some modern glacial areas are still sparse. In this study, we examine for the first time quartz grains sampled from the modern glacial and proglacial environments of the Russell Glacier, southwest Greenland in binocular microscope and scanning electron microscope, to analyze their shape, character of surface and microtextures. We debate whether the investigated quartz grains reveal glacial characteristics and to what extent they carry a signal of another transportation and sedimentary processes. Although glacial fracturing and abrasion occur in grain suites, most mechanical origin features are not of a high frequency or freshness, potentially suggesting a reduced shear stress in the glacier from its limited thickness and influence of the pressurized water at the ice-bed. In contrast, the signal that originates from the fluvial environment is much stronger derived by numerous aqueous-induced features present on quartz grain surfaces. Aeolian-induced microtextures on grain surfaces increase among the samples the closest to the ice margin, which may be due to enhanced aeolian activity, but are practically absent in sediments taken from the small scale aeolian landforms. In contrast, aeolian grains have been found in the bigger-size (1.0–2.0 mm) investigated fraction. These grains gained the strongest aeolian abrasion, possibly due to changes in transportation mode.


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