Long‐Term Sediment Export Estimates from Northern Jordan using Roman Cisterns as Sediment Traps     

Sabine Kraushaar  Gregor Ollesch  Christian Siebert  Hans‐Joerg Vogel  Markus Fuchs 《Geoarchaeology》2015,30(4):369-378

Roman cisterns served as rainwater storage devices for centuries and are densely distributed in parts of northern Jordan. A major earthquake hit the region ca. A.D. 750 and in a short time many settlements were abandoned. As a consequence, most cisterns were not maintained, and they filled with sediments that today provide a postabandonment depositional record. In two field surveys, we mapped the locations of more than 100 cisterns in the Wadi Al‐Arab basin and selected two for detailed stratigraphic analysis that included ¹⁴C and optically stimulated luminescence dating. Catchment basin area for each cistern was determined by differential GPS. Both cisterns filled with sediments after the great earthquake and consequent abandonment of the region. Calculated sediment volumes are translated to long‐term average sediment export rates of 2.6–6.6 t ha⁻¹a⁻¹, which are comparable to erosion and sediment yield rates from other studies within the Mediterranean region. Our pilot study suggests that this approach can be applied elsewhere to calculate long‐term sediment export rates on hill slopes containing relict cisterns.  相似文献   

Tectonic and climatic forcing on the Panj river system during the Quaternary     

Margret C. Fuchs  Richard Gloaguen  Eric Pohl 《International Journal of Earth Sciences》2013,102(7):1985-2003

Surface processes involve complex feedback effects between tectonic and climatic influences in the high mountains of Pamir. The ongoing India–Asia collision provokes the development of east–west-trending mountain ranges that impose structural control on flow directions of the Pamir rivers. The evolving relief is further controlled by strong moisture gradients. The decreasing precipitations from the southern and western margins of the Pamir Plateau to its center, in their turn, control the emplacement of glaciers. Chronologies of glacial records from the Pamir Plateau attest for strong climatic variability during the Quaternary. Corresponding remnants of glacial advances suggest glacial morphodynamic restricted to >4,000 m a.s.l. since marine isotope stage 4. The Panj, the trunk river of Pamir, deflects from the predominant westward drainage, connecting its main tributaries at the western margin of the drainage basin. The geometry of the river network and the pattern of incision characterize the Panj as a composite river. River reaches of indicated low incision coincide with west-trending valleys, parallel to domes and their bounding faults. Valley shape ratios reflect increased incision in north-trending sections, but do not match with changes in the catchment geometry or erodibility of rock types. Modelled riverbed profiles distinguish three Panj reaches. The upstream increase in convexity suggests successive river captures in response to local base-level changes. The northward-deflected river reaches link the local base levels, which coincide with the southern boundaries of the Shakhdara and Yazgulom Dome and Darvaz Range. We argue that tectonics plays a large role controlling the drainage system of the Panj and hence surface processes in the Pamir mountains.  相似文献   

A spatially explicit assessment of current and future hotspots of hunger in Sub-Saharan Africa in the context of global change   总被引：7，自引：0，他引：7  

Junguo Liu  Steffen Fritz  C.F.A. van Wesenbeeck  Michael Fuchs  Liangzhi You  Michael Obersteiner  Hong Yang 《Global and Planetary Change》2008,64(3-4):222

Hunger knows no boundaries or borders. While much research has focused on undernutrition on a national scale, this report evaluates it at subnational levels for Sub-Saharan Africa (SSA) to pinpoint hotspots where the greatest challenges exist. Undernutrition is assessed with a spatial resolution of 30 arc-minutes by investigating anthropometric data on weight and length of individuals. The impact of climate change on production of six major crops (cassava, maize, wheat, sorghum, rice and millet) is analyzed with a GIS-based Environmental Policy Integrated Climate (GEPIC) model with the same spatial resolution. Future hotspots of hunger are projected in the context of the anticipated climate, social, economic, and bio-physical changes. The results show that some regions in northern and southwestern Nigeria, Sudan and Angola with a currently high number of people with undernutrition might be able to improve their food security situation mainly through increasing purchasing power. In the near future, regions located in Ethiopia, Uganda, Rwanda and Burundi, southwestern Niger, and Madagascar are likely to remain hotspots of food insecurity, while regions located in Tanzania, Mozambique and the Democratic Republic of Congo might face more serious undernutrition. It is likely that both the groups of regions will suffer from lower capacity of importing food as well as lower per capita calorie availability, while the latter group will probably have sharper reduction in per capita calorie availability. Special attention must be paid to the hotspot areas in order to meet the hunger alleviation goals in SSA.  相似文献   

Vorläufige Ergebnisse von Gefügeuntersuchungen in den Kitzbühler Alpen     

Alfred Fuchs 《Mineralogy and Petrology》1954,4(1-4):193-202

Ohne ZusammenfassungMit 4 Diagrammen.  相似文献   

Progress report on rhenish massif seismic experiment     

J. Mechie  C. Prodehl  K. Fuchs  W. Kaminski  J. Flick  A. Hirn  J. Ansorge  R. King 《Tectonophysics》1982,90(1-2)

This paper presents some data and results from a seismic refraction experiment, completed mainly in 1979 in the Rhenish Massif, Federal Republic of Germany and extending through Luxembourg and Belgium into the Paris Basin in France.Velocity-depth functions have been derived for each record section independently, based on the assumption that velocity varies only with depth: these models are being improved upon by time-term and ray-tracing methods capable of handling laterally varying velocity structures and by calculating synthetic seismograms.The P_g phase which is observed very clearly on all record sections represents a refracted wave, with velocity generally > 6 km/s, from depths below 1.5–5.5 km. Along the 600 km long main profile one intracrustal reflection can usually be recognized, while from the three shorter crossing profiles in the massif two intracrustal reflectors can always be seen. Beneath much of the main profile the crust-mantle boundary is either a first order discontinuity or thin (< 1 km) transition zone at ~30 km depth. However, beneath the Ardennes and West Eifel there is a 6–12 km thick transition zone before a velocity of 8.1 km/s is reached at ~36 km depth. Beneath the crossing profiles, there is generally a transition zone < 3 km thick between crust and mantle. In some cases, there can be recognized at the top of the mantle a thin high velocity layer which is underlain by a low velocity layer which, in turn, is underlain by a reflector 4–11 km below the crust-mantle boundary.  相似文献   

Primordial refractory metal particles in the Allende meteorite     

M. Blander  L.H. Fuchs  C. Horowitz  R. Land 《Geochimica et cosmochimica acta》1980,44(2):217-223

Refractory metal particles containing Os, Re, W, Mo, Ir, and Ru were observed in a Ca-Al-rich inclusion in the Allende meteorite. These particles are the closest to unaltered primordial metal condensates from a nebula yet reported, and appear to have been isolated from the nebula before the condensation of refractories was complete. Computer calculations of condensation indicate that the temperature of isolation appears to be close to the calculated temperature of first formation of oxides (~ 1620 K at 10^?4 atm) indicating that isolation may have been effected by coating of the particles by oxides.  相似文献   

Preface     

Karl Fuchs  H.P. Boot 《Tectonophysics》1979,56(1-2)

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Composition of metal in type III carbonaceous chondrites and its relevance to the source-assignment of lunar metal     

Louis H. Fuchs  Edward Olsen 《Earth and Planetary Science Letters》1973,18(3):379-384

The metal in seven Type III carbonaceous chondrites has been measured for concentrations of Ni, Co and Cr. Cobalt in kamacite is 3.2 to 5.5 times greater than in taenite on composite grains containing both phases. No correlation was found between the metal compositions and sub-type classification. Ni and Co contents of kamacite from several of the Type III's studied fall outside of the range for these elements in bulk meteoritic metal and are relevant to the assignment of a meteoritic vs a non-meteoritic origin for lunar metal particles in the fines and breccias.  相似文献   

Aircraft icing in visual meterological conditions below low stratus clouds     

W. Fuchs  K. -P. Schickel 《Atmospheric Research》1995,36(3-4)

There are many reports about icing slightly below stratus clouds in visual meteorological conditions (VMC), which obviously occurs very often but not only in polar regions and over the sea. Calculations of the ice shape at the leading edge of aircraft wings and the main rotor blades of helicopters by computers of GMGO (German Military Geophysical Office) and DLR (Deutsche Forschungsanstalt für Luft- and Raumfahrt) show, that this specific ice accretion, which often accumulates to severe icing, depends mostly on two meteorological parameters: liquid water content (LWC) and air temperature, but does not depend on the size of the drizzle droplets in the case of helicopters.  相似文献   

Chronostratigraphy of a sediment record from the Hajar mountain range in north Oman: Implications for optical dating of insufficiently bleached sediments     

M. Fuchs  C. Woda  A. Bürkert 《Quaternary Geochronology》2007,2(1-4):202-207

In this study we report on optical stimulated luminescence (OSL) ages of quartz extracted from a sedimentary record in the N-Oman mountain range. Equivalent dose (D_E) distributions derived from single aliquot measurements (SAR) of small aliquots (ca. 200 grains) were investigated to test whether the skewness and broadness of the dose distribution can be used as criteria for the identification of insufficient bleaching. Furthermore, the methods proposed by Lepper and McKeever [2002 An objective methodology for dose distribution analysis. Radiation Protection Dosimetry 101 (1–4), 349-352]. Singhvi [Juyal, N., Chamyal, L.S., Bhandari, S., Bushan, R., Singhvi, A.K., in press. Continental record of the southwest monsoon during the last 130 ka: evidence from the southern margin of the Thar Desert, India. Quaternary Science Review] and Fuchs and Lang [2001 Fuchs, M., Lang, A., 2001. OSL dating of coarse-grain fluvial quartz using single-aliquot protocols on sediments from NE Peloponnese, Greece. Quaternary Science Review 20, 783–787.] to derive D_E's from insufficiently bleached sediments were compared. At first, the investigations were carried out on artificially bleached, irradiated and mixed quartz material from the Oman study area to simulate insufficiently bleached sediments. Then, the various statistical methods for identifying insufficient bleaching and D_E derivation were applied to the natural samples from the study area, where 18 samples were measured. For the identification of insufficient bleaching the preferential parameter is the broadness of a distribution. For D_E calculation, both the Singhvi method and the Fuchs and Lang method produce similar results, which are consistent with the stratigraphic order. A drawback of both methods is their sensitivity to low outliers. The Lepper and McKeever method was not applied to the natural samples, due to limitations in its application to a small number of aliquots and due to the ambiguous identification of the rising limb of the dose distributions.  相似文献