Genetic relationship between silver–lead–zinc mineralization in the Wutong deposit,Guangxi Province and Mesozoic granitic magmatism in the Nanling belt,southeast China     

Pilar Lecumberri-Sanchez  Rolf L. Romer  Volker Lüders  Robert J. Bodnar 《Mineralium Deposita》2014,49(3):353-369

More than 50 % of the world's total reserves of tungsten are in China and most tungsten deposits are located in the Nanling range in southeast China. This study explores the potential genetic relationship between tungsten–tin (W–Sn) mineralization and shallower Ag–Pb–Zn deposits in the Nanling range based on data from the Wutong deposit, Guangxi Province. The lead, oxygen, carbon, sulfur, and strontium isotopic compositions of minerals at Wutong indicate that a single crustal-derived fluid was responsible for mineralization. Wutong likely formed at relatively low temperatures (～200–300 °C) and low pressures, as indicated by the similarity between homogenization temperatures of fluid inclusions and those estimated from S isotopic compositions of minerals. The hübnerite age (92.3–104.4 Ma) indicates that the Wutong mineralization is likely related to nearby Late Yanshanian (Cretaceous) S-type granites derived from Proterozoic crust. This mineralization event coincides with the last W–Sn mineralization event and the Cretaceous peak of mineralization in the Nanling range.  相似文献   

Deep seismic reflectivity patterns in specific tectonic units of Western and Central Europe   总被引：2，自引：0，他引：2  

Petra Sadowiak  Thomas Wever  Rolf Meissner 《Geophysical Journal International》1991,105(1):45-54

  相似文献   

‘PALEOVAN’, International Continental Scientific Drilling Program (ICDP): site survey results and perspectives     

Thomas Litt  Sebastian Krastel  Michael Sturm  Rolf Kipfer  Sefer Örcen  Georg Heumann  Sven Oliver Franz  Umut B. Ülgen  Frank Niessen 《Quaternary Science Reviews》2009,28(15-16):1555-1567

Lake Van is the fourth largest terminal lake in the world (volume 607 km³, area 3570 km², maximum depth 460 m), extending for 130 km WSW–ENE on the Eastern Anatolian High Plateau, Turkey. The sedimentary record of Lake Van, partly laminated, has the potential to obtain a long and continuous continental sequence that covers several glacial–interglacial cycles (ca 500 kyr). Therefore, Lake Van is a key site within the International Continental Scientific Drilling Program (ICDP) for the investigation of the Quaternary climate evolution in the Near East (‘PALEOVAN’). As preparation for an ICDP drilling campaign, a site survey was carried out during the past years. We collected 50 seismic profiles with a total length of ～850 km to identify continuous undisturbed sedimentary sequences for potential ICDP locations. Based on the seismic results, we cored 10 different locations to water depths of up to 420 m. Multidisciplinary scientific work at positions of a proposed ICDP drill site included measurements of magnetic susceptibility, physical properties, stable isotopes, XRF scans, and pollen and spores. This core extends back to the Last Glacial Maximum (LGM), a more extended record than all the other Lake Van cores obtained to date. Both coring and seismic data do not show any indication that the deepest part of the lake (Tatvan Basin, Ahlat Ridge) was dry or almost dry during past times. These results show potential for obtaining a continuous undisturbed, long continental palaeoclimate record. In addition, this paper discusses the potential of ‘PALEOVAN’ to establish new results on the dynamics of lake level fluctuations, noble gas concentration in pore water of the lake sediment, history of volcanism and volcanic activities based on tephrostratigraphy, and paleoseismic and earthquake activities.  相似文献   

Time variable Earth’s gravity field from SLR satellites   总被引：4，自引：4，他引：0  

Krzysztof Sośnica  Adrian Jäggi  Ulrich Meyer  Daniela Thaller  Gerhard Beutler  Daniel Arnold  Rolf Dach 《Journal of Geodesy》2015,89(10):945-960

  相似文献   

A consistent combination of GNSS and SLR with minimum constraints   总被引：1，自引：1，他引：0  

Susanne Glaser  Mathias Fritsche  Krzysztof Sośnica  Carlos Javier Rodríguez-Solano  Kan Wang  Rolf Dach  Urs Hugentobler  Markus Rothacher  Reinhard Dietrich 《Journal of Geodesy》2015,89(12):1165-1180

  相似文献   

A comment on the article “A collinearity diagnosis of the GNSS geocenter determination” by P. Rebischung,Z. Altamimi,and T. Springer     

Michael Meindl  Gerhard Beutler  Daniela Thaller  Rolf Dach  Stefan Schaer  Adrian Jäggi 《Journal of Geodesy》2015,89(2):189-194

  相似文献   

Calcite Dissolution Kinetics     

Rolf?S.?ArvidsonEmail author  Cornelius?Fischer  Andreas?Luttge 《Aquatic Geochemistry》2015,21(5):415-422

We compare the canonical treatment of calcite’s dissolution rate from the literature in a closed system, particle batch reactor, with the alternative approach suggested by Truesdale (Aquat Geochem, 2015). We show that the decay of rate over time can be understood in terms of the evolution and distribution of reactive sites on the surface of these particles. We also emphasize that interpretation of observed rates must not exclude the fundamental role of crystal defects, whose importance is already implicitly reflected in the common form of rate laws in geochemistry. The empirical behavior of overall rate in closed systems, such as those described by Truesdale, may thus reflect relationships between defect centers and the generation of steps over the calcite surface (previously documented for silicates), such that below a critical free energy limit, there is insufficient driving force to open hollow cores and thus a loss of reaction mechanism. Dissolution in this very-near-equilibrium regime will be dependent on the distribution of extant steps and the energetics of new kink site nucleation. However, these sensitivities are complicated in the case of particle systems by grain boundaries, edges, corners, and other terminations. Such discontinuities constitute a defect class whose overall kinetic importance will be strongly tied to particle diameter and which can act independently of the internal strain field imposed by screw and edge dislocations.  相似文献   

Investigations on the runoff generation at the profile and plot scales,Swiss Emmental     

Alexandre Badoux  Jonas Witzig  Peter F. Germann  Hans Kienholz  Peter Lüscher  Rolf Weingartner  Christoph Hegg 《水文研究》2006,20(2):377-394

This article describes an investigation on runoff generation at different scales in the forested catchment of the Sperbelgraben in the Emmental region (Swiss Prealps) where studies in the field of forest hydrology have a history of 100 years. It focuses on the analysis of soil profiles and the subsequent sprinkling experiments above them (1 m²), as well as on surface runoff measurements on larger plots (50 to 110 m²). In the Sperbelgraben investigation area, two very distinct runoff reactions could be observed. On the one hand, very high production of saturation overland flow was registered on wet areas of gleyic soils, with runoff coefficients between 0·39 and 0·94 for profile irrigation. On the other hand, almost no surface runoff was measured on Cambisols, with the exception at some sites of a hydrophobic reaction detected at the beginning of storms after dry periods (coefficients for profile irrigation: 0·01–0·16). This pattern was observed during 1 m² soil plot irrigation and on surface runoff plots. Apart from a less distinctive signal of the water‐repellent litter layer on the larger surface runoff plots, the dominant hydrological processes at the two scales are the same. The determined runoff reaction at the two scales corresponds well with information from a forest site type map describing soil and vegetation characteristics and used as a substitute for a soil map in this study. Theoretical considerations describing forest influence on flood discharge are discussed and evaluated to be in good agreement with observations. These findings are a sound foundation for application in hydrological catchment modelling. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Zum Problem der Bruchbildung,Schieferung und Faltung     

Rolf Hoeppener 《International Journal of Earth Sciences》1956,45(2):247-283

  相似文献   

Sequestration of a Biologically Labile Organic Carbon in Soils by Humified Organic Matter     

Allessandro Piccolo  Riccardo Spaccini  Rolf Nieder  Joerg Richter 《Climatic change》2004,67(2-3):329-343

In a long-term (one year) experiment, a sandy Podzol and a silty-loamy Loess soil were treated with labile (polysaccharides, AG) and stable (mature compost, CMP, and two humic acids from compost, HAC, and lignite, HAL) organic matter and the organic carbon (OC) lost by mineralization was periodically evaluated. The stable materials alone induced a significant reduction of OC losses in Podzol CMP <, HAL, <, HAC, Control), whereas the same treatments, except for CMP, produced an OC loss larger than control in Loess. This was attributed to the diverse textural and physical status of the two soils. The added stable organic matter became protected in the Podzol soil within the aggregates formed by the interaction with the coarse inorganic phase, while it was more easily decomposed in the Loess soils due to the strength of the native humic-clay complexes. In both soils, when the stable organic materials were mixed with polysaccharides (AG), the OC losses from this labile fraction were significantly reduced, being CMP more OC sequestering than HAC and HAL, in the order. These results confirmed that labile organic matter in soils can be protected from biodegradation by repartition into the hydrophobic domains of the stable, humified organic matter. This study suggests that mature compost and humic acids may usefully integrate management practices aimed to sequester organic carbon in soils.  相似文献