Stehende interne Wellen in rechteckigen Becken     

Dr. Karl-Heinz Keunecke 《Ocean Dynamics》1970,23(2):61-79

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Accelerated plate motion and rates of volcanicity as controls on Archean climates     

Karl-Heinz Wyrwoll  David McConchie 《Climatic change》1986,8(3):257-265

Although vulcanicity is seen as a possible mechanism of climatic change, under present rates of eruptions it is difficult to envisage volcanic activity acting independently of other factors in causing significant and lasting global climate changes. This note considers the global plate-tectonic regime which may have prevailed during the Archean, and which, as a consequence, should have resulted in rates of volcanic eruptions significantly higher than at present. From this would follow atmospheric CO₂ levels significantly higher than those which prevail today. In this note we attempt to establish a link between the Archean global plate-tectonic regime and the high atmospheric CO₂ levels which are thought to have existed at that time.  相似文献   

Zur Staubdichte in Reflexionsnebeln     

Karl-Heinz Schmidt 《Astronomische Nachrichten》1970,292(2):87-91

Assuming an isotropic scattering function of interstellar grains from a discussion of the Hubble relation of the reflection nebulae it follows that for such objects with the illuminating star outside of the nebula a lower limit of the dust density depending on the absolute magnitude of the illuminating star is necessary in order to image the nebula on the Palomar Observatory Sky Survey. The albedo of the grains is larger than γ = 0.6.  相似文献   

DuneXpress     

Eberhard Grün  Ralf Srama  Nicolas Altobelli  Kathrin Altwegg  James Carpenter  Luigi Colangeli  Karl-Heinz Glassmeier  Stefan Helfert  Hartmut Henkel  Mihaly Horanyi  Annette Jäckel  Sascha Kempf  Markus Landgraf  Neil McBride  Georg Moragas-Klostermeyer  Pasquale Palumbo  Han Scholten  Andre Srowig  Zoltan Sternovsky  Xavier Vo 《Experimental Astronomy》2009,23(3):981-999

The DuneXpress observatory will characterize interstellar and interplanetary dust in-situ, in order to provide crucial information not achievable with remote sensing astronomical methods. Galactic interstellar dust constitutes the solid phase of matter from which stars and planetary systems form. Interplanetary dust, from comets and asteroids, represents remnant material from bodies at different stages of early solar system evolution. Thus, studies of interstellar and interplanetary dust with DuneXpress in Earth orbit will provide a comparison between the composition of the interstellar medium and primitive planetary objects. Hence DuneXpress will provide insights into the physical conditions during planetary system formation. This comparison of interstellar and interplanetary dust addresses directly themes of highest priority in astrophysics and solar system science, which are described in ESA’s Cosmic Vision. The discoveries of interstellar dust in the outer and inner solar system during the last decade suggest an innovative approach to the characterization of cosmic dust. DuneXpress establishes the next logical step beyond NASA’s Stardust mission, with four major advancements in cosmic dust research: (1) analysis of the elemental and isotopic composition of individual interstellar grains passing through the solar system, (2) determination of the size distribution of interstellar dust at 1 AU from 10^− 14 to 10^− 9 g, (3) characterization of the interstellar dust flow through the planetary system, (4) establish the interrelation of interplanetary dust with comets and asteroids. Additionally, in supporting the dust science objectives, DuneXpress will characterize dust charging in the solar wind and in the Earth’s magnetotail. The science payload consists of two dust telescopes of a total of 0.1 m² sensitive area, three dust cameras totaling 0.4 m² sensitive area, and a nano-dust detector. The dust telescopes measure high-resolution mass spectra of both positive and negative ions released upon impact of dust particles. The dust cameras employ different detection methods and are optimized for (1) large area impact detection and trajectory analysis of submicron sized and larger dust grains, (2) the determination of physical properties, such as flux, mass, speed, and electrical charge. A nano-dust detector searches for nanometer-sized dust particles in interplanetary space. A plasma monitor supports the dust charge measurements, thereby, providing additional information on the dust particles. About 1,000 grains are expected to be recorded by this payload every year, with 20% of these grains providing elemental composition. During the mission submicron to micron-sized interstellar grains are expected to be recorded in statistically significant numbers. DuneXpress will open a new window to dusty universe that will provide unprecedented information on cosmic dust and on the objects from which it is derived.  相似文献   

青藏高原东北部隆升：来自宁夏同心小洪沟剖面的证据   总被引：3，自引：0，他引：3  

林秀斌  陈汉林  Karl-Heinz Wyrwoll  程晓敢  王旭龙  付可昂  廖林  肖骏  Krapez Bryan 《地质学报》2009,83(4):455-467

青藏高原边界地区的研究,尤其是砾石研究,对探讨青藏高原的隆升过程及隆升机制具有重要意义。本文选取青藏高原东北部香山山前小洪沟剖面,对出露的新生界各层位的砾石进行统计。统计结果显示,该剖面寺口子组上段、红柳沟组下段、红柳沟组上段、第四系以及现今河床出露的砾石成分主要为砂岩和石英砂岩,这与香山地区岩性相符合;砾石主要呈次圆状和次棱角状;长短轴比主要为1至2之间,为近圆状;砾石主要集中在中砾和小砾类别;分选好至中等好。砾石粒径分布显示出向细粒成分偏的特征,主要呈尖峰正态分布。这些特征表明各层位砾石相似的搬运过程,为中距离山前河流冲积砾石。沉积分析表明该砾石与气候振荡无必然联系,为构造隆升的产物。砾石沉积年龄由邻区磁性地层定年结果来限定。砾石特征结合邻区沉积分析表明香山地区在寺口子组沉积时（始新世）沉积之前已具有相当大的高程;至清水营组沉积时（渐新世）,该山体被剥蚀剥蚀夷平;到红柳沟组沉积时（中新世早、中期）,香山经历了再次的隆升;至干河沟组沉积时（中新世晚期到上新世）,构造趋于稳定;到更新世时,再次出现隆升事件。始新世香山山体可能与晚白垩世至新生代早期的构造事件有关,中新世的隆升时间可以作为印－藏碰撞效应到达香山地区的时限,显示青藏高原东北边界新生代的变形隆升时间较前人研究结果早,且存在多期隆升。  相似文献   

International wood trade and forest change: A global analysis     

Thomas Kastner  Karl-Heinz ErbSanderine Nonhebel 《Global Environmental Change》2011,21(3):947-956

Throughout history, humans have transformed natural forests into agricultural land, settlement areas and managed forests. Studies on the dynamics of forest change are one of the mainstays in land change science. The forest transition theory offers a powerful tool to analyze changes in human interference with forests. At the national level, a range of factors have been found to influence a country's forest change. The role of international wood product trade has, however, rarely been studied based on empirical data. We offer a global assessment of how this trade helps shape observed forest change, by relating forest stock change to net trade of wood products for the period 1997-2007 and by localizing the origin of wood consumed in a given nation. For many nations, traded wood products have a relevant impact on the course of ongoing forest transitions. We develop a general typology of how wood product trade can influence forest change and place various nations within this framework. We find that many wealthy nations with returning forests seem to accelerate this return by importing wood products. These imports appear to be provided by two main types of wood exporters: (a) by wealthy countries with low population densities and stable forests and (b) by relatively poor countries with declining forests, employing increasing population and welfare levels. We discuss these findings in the light of general theories on land use transitions and forest change and conclude by highlighting implications for national forest policies and global environmental governance, aiming at reducing negative impacts of wood products and enhancing the positive role they can play in replacing more fossil fuel intensive products.  相似文献   

The Namuskluft and Dreigratberg sections in southern Namibia (Kalahari Craton,Gariep Belt): a geological history of Neoproterozoic rifting and recycling of cratonic crust during the dispersal of Rodinia until the amalgamation of Gondwana     

Mandy Hofmann  Ulf Linnemann  Karl-Heinz Hoffmann  Axel Gerdes  Katja Eckelmann  Andreas Gärtner 《International Journal of Earth Sciences》2014,103(5):1187-1202

This paper presents combined U/Pb, Th/U and Hf isotope analyses on detrital and magmatic zircon grains together with whole-rock geochemical analyses of two basement and eight sedimentary rock samples from the Namuskluft and the Dreigratberg in southern Namibia (Gariep Belt). The sedimentary sections evolved during the Cryogenian on the SW part of the Kalahari Craton and where therefore deposited in an active rift setting during the break-up of Rodinia. Due to insufficient palaeomagnetic data, the position of the Kalahari Craton within Rodinia is still under discussion. There are possibilities to locate Kalahari along the western side of Australia/Mawsonland (Pisarevski et al. in Proterozoic East Gondwana: supercontinent assembly and break-up, Geological Society, London, 2003; Evans in Ancient Orogens and modern analogues. Geological Society, London, 2009; and others) or together with the Congo-Sao Francisco and Rio de la Plata Cratons (Li et al. in Prec Res 45: 203–2014, 2008; Frimmel et al. in Int J Earth Sci (Geol Rundsch) 100: 323–354, 2011; and others). It is sill unclear which craton rifted away from the Kalahari Craton during the Cryogenian. Although Middle to Upper Cryogenian magmatic activity is known for the SE Kalahari Craton (our working area) (Richtersveld Suite, Rosh Pinah Fm), all the presented samples show no U/Pb zircon ages younger than ca. 1.0 Ga and non-older than 2.06 Ga. The obtained U/Pb ages fit very well to the exposed basement of the Kalahari Craton (1.0–1.4 Ga Namaqua Province, 1.7–2.0 Ga Vioolsdrif Granite Suite and Orange River Group) and allow no correlation with a foreign craton such as the Rio de la Plata or Australia/Mawsonland. Lu–Hf isotopic signatures of detrital zircon point to the recycling of mainly Palaeoproterozoic and to a smaller amount of Archean crust in the source areas. εHf(t) signatures range between ?24 and +14.8, which relate to T_DM model ages between 1.05 and 3.1 Ga. Only few detrital zircon grains derived from magmas generated from Mesoproterozoic crustal material show more juvenile εHf(t) signatures of +14, +8 to +4 with T_DM model ages of 1.05–1.6 Ga. During Neoproterozoic deposition, only old cratonic crust with an inherited continental arc signature was available in the source area clearly demonstrated by Hf isotope composition of detrital zircon and geochemical bulk analysis of sedimentary rocks. The granodiorites of the Palaeoproterozoic basement underlying Namuskluft section are ca. 1.9 Ga old and show εHf(t) signatures of ?3 to ?5.5 with T_DM model ages of 2.4–2.7 Ga. These basement rocks demonstrate the extreme uplift and deep erosion of the underlying Kalahari Craton at its western margin before general subsidence during Cryogenian and Ediacaran time. The sedimentary sequence of the two examined sections (Namuskluft and Dreigratberg) proposes the presence of a basin and an increasing subsidence at the SW part of the Kalahari Craton during the Cryogenian. Therefore, we propose the initial formation of an intra-cratonic sag basin during the Lower Cryogenian that evolved later to a rift basin at the cratonic margin due to increasing crustal tension and rifting together with the opening of the Adamastor Ocean. As the zircons of the sedimentary rocks filling this basin show neither rift-related U/Pb ages nor an exotic craton as a possible source area, the only plausible sedimentary transport direction providing the found U/Pb ages would be from the E or the SE, directly from the heart of the Kalahari Craton. Due to subsidence and ongoing sedimentation from E/SE directions, the rift-related magmatic rocks were simply covered by the input of old intra-cratonic material that explains the absence of Neoproterozoic zircon grains in our samples. The geochemical analyses show the erosion of a continental arc and related sedimentary rocks with an overall felsic provenance. The source area was a deeply eroded and incised magmatic arc that evolved on continental crust, without any evidence for a passive margin. All of this can be explained by the erosion of rocks related to the Namaqua Belt, which represents one of the two major peaks of zircon U–Pb ages in all analysed samples. Therefore, the Namaqua Belt was well exposed during the Cryogenian, available to erosion and apart from the also well-exposed Palaeoproterozoic basement of the Kalahari Craton one potential source area for the sedimentary rocks in the investigated areas.  相似文献   

Validity of ocean surface temperatures monitored from satellites     

Szekielda  Karl-Heinz 《ICES Journal of Marine Science》1973,35(1):78-86

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Hydraulic fracturing wastewater in Germany: composition, treatment, concerns   总被引：2，自引：2，他引：0  

Oliver Olsson  Dirk Weichgrebe  Karl-Heinz Rosenwinkel 《Environmental Earth Sciences》2013,70(8):3895-3906

When studying technical methods and measures that could be applicable for flowback treatment, recycling and/or disposal, it is important to characterize the volumes and composition of hydraulic fracturing flowback. In this work, water volumes and water quality data are considered for investigating flowback at three selected drilling sites in Germany. The analysis highlighted an increase of chloride concentrations up to saturation limit over the time. High salinity concentrations were used as indicator for estimating the percentage of hydraulic fracturing fluid and formation water in flowback. For the studied shale gas well a proportion of formation water, 69 %, and hydraulic fracturing fluid, 31 %, in flowback were derived. Thus, 92 % of the hydraulic fracturing fluid remained in the formation. The physical/chemical properties of flowback were categorized in groups to enable the allocation of applicable treatment methods. The analysis revealed that no single technology can meet suitable effluent characteristics, thus two or more treatment systems might be used in series operation. In particular, for flowback containing high salinity concentrations the only treatment options are evaporation or crystallization. Hence, methodological distinctions need to be made between concentration, elimination, disposal and recycling, whereby for the existing concentrate treatment or disposal measures need to be completed and scaled up into the process.  相似文献   

Mean-field electrodynamics: critical analysis of various analytical approaches to the mean electromotive force     

Karl-Heinz Rädler  Matthias Rheinhardt 《地球物理与天体物理流体动力学》2013,107(2):117-154

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