11,685 research outputs found

    Data on the terrestrial Isopoda fauna of the Alsó-hegy, Aggtelek National Park, Hungary

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    Field surveys in dolines of Alsó-hegy, Aggtelek Karst (Hungary) yielded 10 terrestrial isopod species. Despite of the relatively low species richness, we would like to emphasize the high naturalness of the area indicated by the presence of endemic and rare species

    Geomorphology of the Durmitor Mountains and surrounding plateau Jezerska Površ (Montenegro)

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    The geomorphological map of the northeastern Durmitor Mountains and the plateau Jezerska Povrs. (1: 10,000, 47 km(2), Montenegro, Dinaric Alps) was prepared from an intensive fieldwork campaign and remote sensing analysis, and was compiled within a GIS. The basic components of the legend are (i) processes/genesis, (ii) materials, (iii) morphometry/morphography, (iv) hydrography, (v) vegetation and (vi) anthropogenic features. The geomorphological setting of the area consists of Mesozoic limestones which are physically deformed by Quaternary glacial and periglacial activity and chemically affected during interglacials. Glacial deposits on the plateau of three middle-to-late Pleistocene glacial phases are intersected by a well-developed network of palaeo meltwater channels. In the mountains, Holocene glacier retreat left behind a series of well-preserved recessional moraines. The map serves as a valuable tool for Quaternary research in the Durmitor Mountains, and also in other mountains of the Western Balkans

    Seasonal changes in dry matter yield from Karst pastures as influenced by morphoclimatic features

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    Pastures are strongly affected by local environmental variables in terms of their species richness, plant composition and herbage production. A multi-site monitoring study was conducted over three years to investigate the influence of morphoclimatic factors on the seasonal variations in dry matter (DM) yield from Karst pastures. Seven sites located on the Italian and Slovenian Karst regions were investigated that differed in terms of their geological and geomorphological features, as well as their soil types. At each site, the daily DM yield (kg ha-1 d-1) was determined using Corral-Fenlon method which permits to simulate herbage utilization from grazing herds. The morphoclimatic features were also analysed, with the aim to evaluate the link between seasonal DM yield and geomorphological and environmental factors. Generalized non-linear mixed models were built to study the observed seasonal variations in DM yield, using day of the year (DOY), growing degree days (GDD), and cumulative rainfall. Furthermore, environmental descriptors were included in the model in order to evaluate their effects on DM yield. The seasonal variations in yield showed two growing periods (spring and late summer), which were described by Gaussian curves. For the spring growing period, the model improved when the interaction between soil granulometry and growing degree days corresponding to the curve peak was taken into account. This confirms the influence of soil type and air temperature on pasture yield. For the late summer growing period, the interaction between the sand classes and the number of rainy days from the beginning of the period to the peak of the curve improved the model. The curve parameters of our models are correlated with environmental descriptors depending on the lithology and particle size of soils. The results are essential for the optimization of pasture management and avoiding degradation due to over- or under-grazing

    Bunker Cave stalagmites: an archive for central European Holocene climate variability

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    Holocene climate was characterised by variability on multi-centennial to multi-decadal time scales. In central Europe, these fluctuations were most pronounced during winter. Here we present a record of past winter climate variability for the last 10.8 ka based on four speleothems from Bunker Cave, western Germany. Due to its central European location, the cave site is particularly well suited to record changes in precipitation and temperature in response to changes in the North Atlantic realm. We present high-resolution records of δ18O, δ13C values and Mg/Ca ratios. Changes in the Mg/Ca ratio are attributed to past meteoric precipitation variability. The stable C isotope composition of the speleothems most likely reflects changes in vegetation and precipitation, and variations in the δ18O signal are interpreted as variations in meteoric precipitation and temperature. We found cold and dry periods between 8 and 7 ka, 6.5 and 5.5 ka, 4 and 3 ka as well as between 0.7 and 0.2 ka. The proxy signals in the Bunker Cave stalagmites compare well with other isotope records and, thus, seem representative for central European Holocene climate variability. The prominent 8.2 ka event and the Little Ice Age cold events are both recorded in the Bunker Cave record. However, these events show a contrasting relationship between climate and δ18O, which is explained by different causes underlying the two climate anomalies. Whereas the Little Ice Age is attributed to a pronounced negative phase of the North Atlantic Oscillation, the 8.2 ka event was triggered by cooler conditions in the North Atlantic due to a slowdown of the thermohaline circulation

    Book reviews and Book notice

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    Book reviews and Book notice from Volume 2, Number 2, 1968 of Earth Science Journal

    Fold structure and underground drainage pattern in the alpine karst system Hochifen-Gottesacker

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    Abstract.: This paper summarises seven years of hydrogeological research in the alpine karst system Hochifen-Gottesacker (Germany/Austria). Geologically, the site belongs to the Helvetic nappes and consists of Cretaceous sedimentary rocks. The Schrattenkalk limestone forms a relatively thin karst aquifer above or between thick marl aquicludes, forcing groundwater to flow parallel to the strata. The limestone is intensively cut by faults and fractures favouring karstification. The fault offsets are relatively small, so that their influence on the large-scale groundwater flow paths is limited. The site is thus ideal to study the influence of fold structures on the drainage pattern. Multi-tracer tests with a total of 16 injections demonstrated that troughs of plunging synclines form the main underground flow paths, while crests of anticlines act as local groundwater divides in the higher karst zones where the base of the aquifer is above the level of the surrounding valleys. In an adjacent valley that receives inflow from several synclines, tracer tests confirmed a major underground drainage system running across the folds. An axial culmination in the area is part of the continental water divide Rhine-Danube; an axial depression acts as a zone of confluenc

    Hydrochemistry and stable isotopes (δ 18 O and δ 2 H) tools applied to the study of karst aquifers in Southern Mediterranean basin (Teboursouk area, NW Tunisia)

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    Karst aquifers receive increasing attention in Mediterranean countries as they provide large supplies water used for drinkable and irrigation purposes as well as for electricity production. In Teboursouk basin, Northwestern Tunisia, characterized by a typical karst landscape, the water hosted in the carbonates aquifers provides large parts of water supply for drinkable water and agriculture purposes. Groundwater circulation in karst aquifers is characterized by short residence time and low water-rock interaction caused by high karstification processes in the study area. Ion exchange process, rock dissolution and rainfall infiltration are the principal factors of water mineralization and spatial distribution of groundwater chemistry. The present work attempted to study karstic groundwater in Teboursouk region using hydrochemistry and stable isotopes (δ18O and δ2H) tools. Karst aquifers have good water quality with low salinity levels expressed by TDS values largely below 1.5 g/l with Ca-SO4-Cl water type prevailing in the study area. The aquifers have been recharged by rainfall originating from a mixture of Atlantic and Mediterranean vapor masses

    The role of GPR techniques in determining ice cave properties: Peña Castil ice cave, Picos de Europa

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    Producción CientíficaThe structure and ice content of ice caves are poorly understood. Ground penetrating radar (GPR) can provide useful insights but has only rarely been applied to ice caves. This paper interprets GPR images (radargrams) in terms of internal structure, stratification, compaction, thickness and volume of the ice block in the Peña Castil ice cave (Central Massif of Picos de Europa, northern Spain), providing the endokarst geometry of the ice cave in GPR data reflections. Eight radargrams were obtained by applying a shielded ground‐coupled antenna with a nominal frequency of 400 MHz. Although the radargrams do not depict the ice–basal bedrock interface, they suggest that the ice block is at least 54 m deep and similarly thick. Some curved reflection signatures suggest a potential vertical displacement in the block of ice, and thus certain dynamics in the ice body. Other images show numerous interbedded clasts and thin sediment layers imaged as banded reflections. In this particular cave a direct visual inspection of the ice stratigraphy is a difficult task but GPR provides clear reflectivity patterns of some of its internal features, making GPR a suitable instrument for this and future studies to achieve a better and broader understanding of the internal behavior of ice caves.Ministerio de Economía, Industria y Competitividad (project CGL2015-68144-R)Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente (project OAPN-053/2010
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