Search results for "Loess"
showing 10 items of 30 documents
Combining land preparation and vegetation restoration for optimal soil eco-hydrological services in the Loess Plateau, China
2019
Abstract In semiarid terrestrial ecosystems, optimized eco-rehabilitation strategies, such as land preparations and planting vegetation, are keys to achieve a successful ecological restoration. Land preparations and vegetation are supposed to have the coupled and respective impacts on soil ecosystem services, which are still unclear now. In this study, eighteen experimental plots with six different combinations and repetitions of land preparations and vegetation were built in the Chinese Loess Plateau in 2014 and soil moisture storages (SMS), soil carbon stocks (SCS) and other soil nutrient stocks were calculated at 0–100 cm, also the effects of land preparations and planting vegetation on …
RADIUS - rapid particle analysis of digital images by ultra-high-resolution scanning of thin sections
2005
RADIUS is a newly developed particle-size measurement technique, based on evaluation of digital images of thin sections. Analyses are performed with sub-millimetre sample resolution and are thus designed to work on a single lamina of laminated sediments. The method covers grain sizes from medium silt to coarse sand. The application contains pattern-recognition modules that allow the detection of typical particle distributions of loess, organic detritus, turbidites and tephra layers. Cutting and hiding effects of particles on thin sections are corrected by empirical correction matrices. The calculated analysis results are compared with manually counted and measured samples to calibrate the a…
14. Abrupt cooling events at the very end of the last interglacial
2007
Abstract A comparison of a last interglacial annually laminated and varve counted maar lake record from the Eifel/Germany, with a laminated lake sediment record from Northern Germany, shows that high-resolution cores can be correlated across central Europe by dust/loess content, if the resolution of grain-size data is on the order of decades/centuries. Phases of widespread dust dispersal are the same as the cold events in the Greenland ice and North Atlantic sea-surface temperature patterns. The first occurrence of dust in Northern Germany and in the Eifel is during the late Eemian aridity pulse (LEAP, Sirocko et al., 2005) which is called C26 in ocean records (McManus, this volume). This c…
Occurrence and Genesis of Palygorskite and Associated Clay Minerals in a Pleistocene Calcrete Complex, Sde Boqer, Negev Desert, Israel
1996
AbstractPalygorskite and associated clay minerals have been studied in a Pleistocene calcrete complex from the Negev desert (Sde Boqer, Israel). This complex is divided into five main parts: the chalky and marly bedrock overlain by its weathered product, a brecciated calcrete hardpan; the laminar crust; loess pockets trapped in the calcrete; and the overlying soft surficial soil. The distribution of clay minerals is directly dependent on the position of the sample in the calcrete complex. Smectite is inherited from the bedrock in the calcrete with an aeolian enrichment in loess pockets and upper soft soil. The source of kaolinite is mainly detrital, related to desert dust. Illite is partly …
Mineralverwitterung, tonmineralbildung und rubefizierung in Terrae calcis der slowakei Ein beitrag zum paläoklimatischen aussagewert von kalkstein-Ro…
1984
Mineral weathering, clay mineral formation and rubefication of Terrae calcis in Slovakia — A contribution to paleoclimatic evidence of limestone Rotlehm (terra rossa) in Central Europe Limestone Rotlehm (Terra rossa) is very often interpreted as a product of intensive mineral weathering and clay formation under subtropic (to tropic) climate. Especially the formation of hematite in soils as the main process of rubefication is generally believed to occur only in warm climates with a seasonal alternation of precipitation and drought. Fossil or relict Terrae rossae in Central Europe are therefore very often considered as witnesses of a corresponding paleoclimate. On the other side many authors …
Periglacial transport distance of Pb derived from small-scale ore veins in the Rhenish Slate Mountains
2008
Abstract The spatial extent of metal contamination caused by small-scale ore veins is increased by periglacial solifluction. Our objectives were (1) to examine the spatial distribution of Pb in cover beds that migrated over Pb ore veins, (2) to calculate the transport distance of ore-derived Pb, and (3) to determine controls on the transport distance. We examined six transects (320–775 m long) in the Rhenish Slate Mountains in West Germany. The transects included four west-exposed and two east-exposed slopes with inclinations between 2–20°. All transects were forest-covered and located at 280–450 m above sea level. Soils were Dystric Cambisols and Stagnic Luvisols. Samples of 120 B horizons…
Luminescence dating of loess deposits from the Remagen-Schwalbenberg site, Western Germany
2015
Geochronometria 42(1), 67-77 (2015). doi:10.1515/geochr-2015-0008
Sensitivity of extreme rainfall to temperature in semi-arid Mediterranean regions
2019
Abstract Warmer air has the potential to hold more water vapour and, therefore, to provide more water to rainfall events. Studying the relationship between rainfall and temperature represents an emerging issue in hydrology and meteorology, since it can be considered fundamental for evaluating the effects of global warming on future precipitation. Various approaches have been tested across different parts of the world, in many cases observing an intensification of extreme precipitation at higher temperatures consistent with the well-known thermodynamic Clausius-Clapeyron relation (CC-scaling rate of 6–7%°C−1). However, at different locations for hourly time-scales, the temperature-extreme ra…
New national and regional bryophyte records, 42
2015
1. Acaulon triquetrum (Spruce) Mull.Hal.Contributors: S. Grdovic, A. Sabovljevic and M.S. SabovljevicSerbia: Belgrade, Bežanijska kosa, on loess soil, 16 March 2013, leg./det. Aneta Sabovljevic & M...
A comparison of nonparametric methods in the graduation of mortality: Application to data from the Valencia Region (Spain)
2006
[EN] The nonparametric graduation of mortality data aims to estimate death rates by carrying out a smoothing of the crude rates obtained directly from original data. The main difference with regard to parametric models is that the assumption of an age-dependent function is unnecessary, which is advantageous when the information behind the model is unknown, as one cause of error is often the choice of an inappropriate model. This paper reviews the various alternatives and presents their application to mortality data from the Valencia Region, Spain. The comparison leads us to the conclusion that the best model is a smoothing by means of Generalised Additive Models (GAM) with splines. The most…