Depositional rates and dating techniques of modern deposits in the Brno reservoir (Czech Republic) during the last 70 years     

Slavomír Nehyba  Daniel Nývlt  Uwe Schkade  Gerald Kirchner  Eva Franců 《Journal of Paleolimnology》2011,45(1):41-55

Facies analysis, magnetic susceptibility, and analysis of grain size, TOC content and isotopes (¹³⁷Cs, ²¹⁰Pb, ²²⁶Ra, ²²⁸Ra, and ²³⁸U concentrations) were used to determine the history of the modern deposits of the Brno reservoir. The sedimentary succession can be subdivided into two main units. The lower unit is formed predominantly by medium- to coarse-grained silty sands and is interpreted as a fluvial succession deposited before the Svratka River was dammed. The upper unit consists of brownish planar laminated silts and rarely of clayey or sandy silts and is interpreted as a product of the reservoir deposition. The concentrations of ²³⁸U reflect the history of uranium mining in the upper part of the Svratka River catchment. As a consequence, ²¹⁰Pb radionuclide concentrations cannot be used for establishing a sediment chronology. Concentrations of ¹³⁷Cs show two marked peaks, the upper of which is attributed to the Chernobyl reactor accident in 1986, and the lower one is attributed to the maximum rate of atomic weapons testing in 1963. From these peaks, mean depositional rates of 3.2 cm year⁻¹ for the time period of 1986–2007 and of 3.4 cm year⁻¹ between 1963 and 1986 are calculated. Based on the known age of the reservoir, which was constructed in 1939, we can also calculate mean depositional rate for the time period of 1939–1963, which is 3.1 cm year⁻¹.  相似文献   

Understanding the active tectonics in Australia: constraints from isotope dating and tracing     

I.Tongu? UYSAL  ZHAO Jianxin  Uwe RING 《《地质学报》英文版》2013,87(Z1):389-389

  相似文献   

Geostandards and Geoanalytical Research Bibliographic Review 2011     

Klaus Peter Jochum  Uwe Nohl  Nadja Rothbarth  Beate Schwager  Brigitte Stoll  Ulrike Weis 《Geostandards and Geoanalytical Research》2012,36(4):415-419

  相似文献   

The Impact Crater Bandwagon (Some problems with the terrestrial impact cratering record)     

Wolf Uwe Reimold 《Meteoritics & planetary science》2007,42(9):1467-1472

  相似文献   

Lessons Learned and Future Challenges for Integrated and Participatory Approaches to Mountain Research——Conclusions from the Mountain Symposium and this Special Issue     

Franz Heidhues  Karl Stahr  Uwe Jens Nagel  David Thomas  Andreas Neef 《山地科学学报》2006,(4)

  相似文献   

Geostandards and Geoanalytical Research Bibliographic Review 2015   总被引：1，自引：0，他引：1       下载免费PDF全文

Ulrike Weis  Beate Schwager  Uwe Nohl  Patricia Karlowski  Laura M. Otter  Brigitte Stoll  Klaus Peter Jochum 《Geostandards and Geoanalytical Research》2016,40(4):599-601

  相似文献   

Delineation of spatial-temporal patterns of groundwater/surface-water interaction along a river reach (Aa River,Belgium) with transient thermal modeling     

Christian Anibas  Abebe Debele Tolche  Gert Ghysels  Jiri Nossent  Uwe Schneidewind  Marijke Huysmans  Okke Batelaan 《Hydrogeology Journal》2018,26(3):819-835

Among the advances made in analytical and numerical analysis methods to quantify groundwater/surface-water interaction, one methodology that stands out is the use of heat as an environmental tracer. A large data set of river and riverbed temperature profiles from the Aa River in Belgium has been used to examine the spatial-temporal variations of groundwater/surface-water interaction. Exchange fluxes were calculated with the numerical heat-transport code STRIVE. The code was applied in transient mode to overcome previous limitations of steady-state analysis, and allowed for the calculation of model quality. In autumn and winter the mean exchange fluxes reached ?90 mm d^?1, while in spring and early summer fluxes were ?42 mm d^?1. Predominantly gaining conditions occurred along the river reach; however, in a few areas the direction of flow changed in time. The river banks showed elevated fluxes up to a factor of 3 compared to the center of the river. Higher fluxes were detected in the upstream section of the reach. Due to the influence of exchange fluxes along the river banks, larger temporal variations were found in the downstream section. The exchange fluxes at the river banks seemed more driven by variable local exchange flows, while the center of the river was dominated by deep and steady regional groundwater flows. These spatial and temporal differences in groundwater/surface-water exchange show the importance of long-term investigations on the driving forces of hyporheic processes across different scales.  相似文献   

Stereo analysis of high-resolution SAR images for building height estimation in cases of orthogonal aspect directions     

Uwe Soergel  Eckart Michaelsen  Antje Thiele  Erich Cadario  Ulrich Thoennessen 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(5):490-500

SAR stereo image analysis for 3D information extraction is mostly carried out based on imagery taken under same-side or opposite-side viewing conditions. For urban scenes in practice stereo is up to now usually restricted to the first configuration, because increasing image dissimilarity connected with rising illumination direction differences leads to a lack of suitable features for matching, especially in the case of low or medium resolution data. However, due to two developments SAR stereo from arbitrary viewing conditions becomes an interesting option for urban information extraction. The first one is the availability of airborne sensor systems, which are capable of more flexible data acquisition in comparison to satellite sensors. This flexibility enables multi-aspect analysis of objects in built-up areas for various kinds of purpose, such as building recognition, road network extraction, or traffic monitoring. The second development is the significant improvement of the geometric resolution providing a high level of detail especially of roof features, which can be observed from a wide span of viewpoints. In this paper, high-resolution SAR images of an urban scene are analyzed in order to infer buildings and their height from the different layover effects in views taken from orthogonal aspect angles. High level object matching is proposed that relies on symbolic data, representing suitable features of urban objects. Here, a knowledge-based approach is applied, which is realized by a production system that codes a set of suitable principles of perceptual grouping in its production rules. The images are analyzed separately for the presence of certain object groups and their characteristics frequently appearing on buildings, such as salient rows of point targets, rectangular structures or symmetries. The stereo analysis is then accomplished by means of productions that combine and match these 2D image objects and infer their height by 3D clustering. The approach is tested using real SAR data of an urban scene.  相似文献   

Regression models for daily stream temperature simulation: case studies for the river Elbe,Germany     

Hagen Koch  Uwe Grünewald 《水文研究》2010,24(26):3826-3836

Daily stream temperatures are needed in a number of analyses. Such analyses might focus on aquatic organisms or industrial activities. To protect aquatic systems, industrial activities, for example, water withdrawals or discharges, are sometimes restricted. To evaluate where new industrial settings should be placed or if climate change will affect already existing industrial settings, the simulation of stream temperature is needed. Stream temperature models with weekly or monthly time scale might not be sufficient for this kind of analysis. Different regression models to simulate daily stream temperature for the river Elbe (Germany) are developed and their performance is estimated. For the calibration period the Nash–Sutcliffe coefficient (NSC) for the simplest model is 0·97, and the root mean squared error (RMSE) is 1·48 °C. For the most sophisticated model the NSC also is 0·97. However, the RMSE is 1·32 °C. For the validation period the NSC for the simplest model is 0·96, and the RMSE is 1·45 °C. The NSC for the most sophisticated model is 0·97, and the RMSE is 1·25 °C. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Hydrogen bonding in coquimbite, nominally Fe2(SO4)3·9H2O, and the relationship between coquimbite and paracoquimbite     

Juraj Majzlan  Tamara Ðorđević  Uwe Kolitsch  Jürg Schefer 《Mineralogy and Petrology》2010,100(3-4):241-248

Using single-crystal X-ray diffraction at 293, 200 and 100 K, and neutron diffraction at 50 K, we have refined the positions of all atoms, including hydrogen atoms (previously undetermined), in the structure of coquimbite ( $ P {\bar 3}1c $ , a?=?10.924(2)/10.882(2) Å, c?=?17.086(3) / 17.154(3) Å, V?=?1765.8(3)/1759.2(5) ų, at 293 / 50 K, respectively). The use of neutron diffraction allowed us to determine precise and accurate hydrogen positions. The O–H distances in coquimbite at 50 K vary between 0.98 and 1.01 Å. In addition to H₂O molecules coordinated to the Al³⁺ and Fe³⁺ ions, there are rings of six “free” H₂O molecules in the coquimbite structure. These rings can be visualized as flattened octahedra with the distance between oxygen and the geometric center of the polyhedron of 2.46 Å. The hydrogen-bonding scheme undergoes no changes with decreasing temperature and the unit cell shrinks linearly from 293 to 100 K. A review of the available data on coquimbite and its “dimorph” paracoquimbite indicates that paracoquimbite may form in phases closer to the nominal composition of Fe₂(SO₄)₃·9H₂O. Coquimbite, on the other hand, has a composition approximating Fe_1.5Al_0.5(SO₄)₃·9H₂O. Hence, even a “simple” sulfate Fe_2-x Al _x (SO₄)₃·9H₂O may be structurally rather complex.  相似文献