Traces of ancient geysers preserved in the travertine of Siwaqa,Jordan: conditions of their formation     

Ikhlas Alhejoj  Klaus Bandel  Elias Salameh  Khitam Alzughoul 《Environmental Earth Sciences》2018,77(7):281

A Pleistocene travertine quarrying on a hill in Siwaqa area, central Jordan, excavated solid, well-stratified travertine beds of about 12 m in thickness. The fabric and composition of the travertine indicate original deposition from hot spring water. At present, the area and its surrounding are devoid of any perennial water, except for periodic flood flows that collect at Siwaqa dam 4–5 km to the west of the quarry area, joining the catchment of the River Mujib. The travertine overlies combusted oil shale. The exposed hot spring travertine consists predominantly of well-bedded limestone, interrupted by horizons of chaotic angular debris, indicating ejection from below such as those produced by geysers. The article discusses the origins of the mottled and angular rock fragments, their transportation due to explosive geyser, the conditions and possible causes that produced the pressures leading to steam outbreaks and are responsible for the observed redistribution of travertine layers.  相似文献   

Government-Funded Deep Geophysical Surveys to Encourage Mineral Exploration: Results from the Western Australian “Exploration Incentives Scheme”     

Michael Dentith  Klaus Gessner  Simon Johnson  Ruth Murdie  Perla Pina-Varas  Jessica Spratt  Ian Tyler  Huaiyu Yuan 《《地质学报》英文版》2018,92(Z1):16-17

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Rutile R632 – A New Natural Reference Material for U‐Pb and Zr Determination          下载免费PDF全文

Emelie Axelsson  Jonas Pape  Jasper Berndt  Fernando Corfu  Klaus Mezger  Michael M. Raith 《Geostandards and Geoanalytical Research》2018,42(3):319-338

A new natural rutile reference material is presented, suitable for U‐Pb dating and Zr‐in‐rutile thermometry by microbeam methods. U‐Pb dating of rutile R632 using laser ablation ICP‐MS with both magnetic sector field and quadrupole instruments as well as isotope dilution‐thermal ionisation mass spectrometry yielded a concordia age of 496 ± 2 Ma. The high U content (> 300 μg g^?1) enabled measurement of high‐precision U‐Pb ages despite its young age. The sample was found to have a Zr content of 4294 ± 196 μg g^?1, which makes it an excellent complementary reference material for Zr‐in‐rutile thermometry. Individual rutile grains have homogeneous compositions of a number of other trace elements including V, Cr, Fe, Nb, Mo, Sn, Sb, Hf, Ta and W. This newly characterised material significantly expands the range of available rutile reference materials relevant for age and temperature determinations.  相似文献   

Application of Bayesian Generative Adversarial Networks to Geological Facies Modeling     

Feng  Runhai  Grana  Dario  Mukerji  Tapan  Mosegaard  Klaus 《Mathematical Geosciences》2022,54(5):831-855

Mathematical Geosciences - Geological facies modeling is a key component in exploration and characterization of subsurface reservoirs. While traditional geostatistical approaches are still commonly...  相似文献   

Empirical assessment of rockfall and debris flow risk along the Karakoram Highway,Pakistan     

Ali  Sajid  Haider  Rashid  Abbas  Wahid  Basharat  Muhammad  Reicherter  Klaus 《Natural Hazards》2021,106(3):2437-2460

Natural Hazards - The Karakoram Highway links north Pakistan with southwest China. It passes through unique geomorphological, geological and tectonic setting. This study focused 200-km-long section...  相似文献   

Blind Source Separation for Compositional Time Series     

Nordhausen  Klaus  Fischer  Gregor  Filzmoser  Peter 《Mathematical Geosciences》2021,53(5):905-924

Many geological phenomena are regularly measured over time to follow developments and changes. For many of these phenomena, the absolute values are not of interest, but rather the relative information, which means that the data are compositional time series. Thus, the serial nature and the compositional geometry should be considered when analyzing the data. Multivariate time series are already challenging, especially if they are higher dimensional, and latent variable models are a popular way to deal with this kind of data. Blind source separation techniques are well-established latent factor models for time series, with many variants covering quite different time series models. Here, several such methods and their assumptions are reviewed, and it is shown how they can be applied to high-dimensional compositional time series. Also, a novel blind source separation method is suggested which is quite flexible regarding the assumptions of the latent time series. The methodology is illustrated using simulations and in an application to light absorbance data from water samples taken from a small stream in Lower Austria.

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A new type of article for Terra Nova          下载免费PDF全文

Max Coleman  Jean Braun  Georges Calas  Carlo Doglioni  Klaus Mezger  Jason Phipps Morgan 《地学学报》2015,27(6):399-399

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Variability of winter extreme precipitation in Southeast China: contributions of SST anomalies     

Ling Zhang  Frank Sielmann  Klaus Fraedrich  Xiuhua Zhu  Xiefei Zhi 《Climate Dynamics》2015,45(9-10):2557-2570

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Experimental impact cratering: A summary of the major results of the MEMIN research unit          下载免费PDF全文

Thomas Kenkmann  Alex Deutsch  Klaus Thoma  Matthias Ebert  Michael H. Poelchau  Elmar Buhl  Eva-Regine Carl  Andreas N. Danilewsky  Georg Dresen  Anja Dufresne  Nathanaël Durr  Lars Ehm  Christian Grosse  Max Gulde  Nicole Güldemeister  Christopher Hamann  Lutz Hecht  Stefan Hiermaier  Tobias Hoerth  Astrid Kowitz  Falko Langenhorst  Bernd Lexow  Hanns-Peter Liermann  Robert Luther  Ulrich Mansfeld  Dorothee Moser  Manuel Raith  Wolf Uwe Reimold  Martin Sauer  Frank Schäfer  Ralf Thomas Schmitt  Frank Sommer  Jakob Wilk  Rebecca Winkler  Kai Wünnemann 《Meteoritics & planetary science》2018,53(8):1543-1568

This paper reviews major findings of the Multidisciplinary Experimental and Modeling Impact Crater Research Network (MEMIN). MEMIN is a consortium, funded from 2009 till 2017 by the German Research Foundation, and is aimed at investigating impact cratering processes by experimental and modeling approaches. The vision of this network has been to comprehensively quantify impact processes by conducting a strictly controlled experimental campaign at the laboratory scale, together with a multidisciplinary analytical approach. Central to MEMIN has been the use of powerful two-stage light-gas accelerators capable of producing impact craters in the decimeter size range in solid rocks that allowed detailed spatial analyses of petrophysical, structural, and geochemical changes in target rocks and ejecta. In addition, explosive setups, membrane-driven diamond anvil cells, as well as laser irradiation and split Hopkinson pressure bar technologies have been used to study the response of minerals and rocks to shock and dynamic loading as well as high-temperature conditions. We used Seeberger sandstone, Taunus quartzite, Carrara marble, and Weibern tuff as major target rock types. In concert with the experiments we conducted mesoscale numerical simulations of shock wave propagation in heterogeneous rocks resolving the complex response of grains and pores to compressive, shear, and tensile loading and macroscale modeling of crater formation and fracturing. Major results comprise (1) projectile–target interaction, (2) various aspects of shock metamorphism with special focus on low shock pressures and effects of target porosity and water saturation, (3) crater morphologies and cratering efficiencies in various nonporous and porous lithologies, (4) in situ target damage, (5) ejecta dynamics, and (6) geophysical survey of experimental craters.  相似文献   

Numerical modeling of toxic nonaqueous phase liquid removal from contaminated groundwater systems: mesh effect and discretization error estimation          下载免费PDF全文

Chongbin Zhao  Thomas Poulet  Klaus Regenauer‐Lieb 《国际地质力学数值与分析法杂志》2015,39(6):571-593

Numerical modeling has now become an indispensable tool for investigating the fundamental mechanisms of toxic nonaqueous phase liquid (NAPL) removal from contaminated groundwater systems. Because the domain of a contaminated groundwater system may involve irregular shapes in geometry, it is necessary to use general quadrilateral elements, in which two neighbor sides are no longer perpendicular to each other. This can cause numerical errors on the computational simulation results due to mesh discretization effect. After the dimensionless governing equations of NAPL dissolution problems are briefly described, the propagation theory of the mesh discretization error associated with a NAPL dissolution system is first presented for a rectangular domain and then extended to a trapezoidal domain. This leads to the establishment of the finger‐amplitude growing theory that is associated with both the corner effect that takes place just at the entrance of the flow in a trapezoidal domain and the mesh discretization effect that occurs in the whole NAPL dissolution system of the trapezoidal domain. This theory can be used to make the approximate error estimation of the corresponding computational simulation results. The related theoretical analysis and numerical results have demonstrated the following: (1) both the corner effect and the mesh discretization effect can be quantitatively viewed as a kind of small perturbation, which can grow in unstable NAPL dissolution systems, so that they can have some considerable effects on the computational results of such systems; (2) the proposed finger‐amplitude growing theory associated with the corner effect at the entrance of a trapezoidal domain is useful for correctly explaining why the finger at either the top or bottom boundary grows much faster than that within the interior of the trapezoidal domain; (3) the proposed finger‐amplitude growing theory associated with the mesh discretization error in the NAPL dissolution system of a trapezoidal domain can be used for quantitatively assessing the correctness of computational simulations of NAPL dissolution front instability problems in trapezoidal domains, so that we can ensure that the computational simulation results are controlled by the physics of the NAPL dissolution system, rather than by the numerical artifacts. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献