Optically stimulated luminescence dating of fluvioglacial (sandur) sediments from north-eastern Germany     

Christopher Lüthgens  Matthias Krbetschek  Margot Böse  Margret C. Fuchs 《Quaternary Geochronology》2010,5(2-3):237-243

This study presents first results of a project which aims to develop an absolute chronology of the Weichselian ice marginal positions in north-eastern Germany using Optically Stimulated Luminescence (OSL) dating. Owing to the special geomorphological and stratigraphical setting, many of the sampling sites were situated close to the former ice margin. At some sections the sediments showed an incomplete resetting of the OSL signal. For this study the representative sandur sediment section from the Beelitz outwash cone was chosen to elaborate a strategy to reliably detect insufficient bleaching and to choose an appropriate age model for the calculation of the true burial dose of each sample. The age determined for the formation of the Beelitz outwash cone is 34.1 ± 3.0 ka. Although this age might still be a maximum age, this study shows that by applying the proposed methodological strategy, plausible ages can be derived from insufficiently bleached, ice proximal sandur sediments.  相似文献   

A 20 ka sediment record from the Hajar Mountain range in N-Oman,and its implication for detecting arid–humid periods on the southeastern Arabian Peninsula     

Markus Fuchs  Andreas Buerkert 《Earth and Planetary Science Letters》2008,265(3-4):546-558

Playa-like sediments from the Hajar Mountain range in northern Oman (22.83°N, 59.00°E; 1050 m asl) document variations of the paleoenvironmental and paleoclimate conditions over the last 20 ka. Based on high-resolution sediment sampling and their OSL dating, sedimentation rates were calculated and used as a proxy for paleorainfall. The results show that the Glacial to Lateglacial was characterized by arid conditions with a following transitional period of even less rainfall. At 10.5 ka, sedimentation rates increases abruptly, indicating the onset of the early Holocene humid period (EHHP). Rainfall reaches its maximum at 9–8 ka (EHHP-2) and a decreasing sedimentation rate after 8 ka characterizes the arid period of the middle to late Holocene. Variations of the hydrological regime are associated with the intensity of the boreal summer Indian monsoon and its related position of the ITCZ. For the onset of the EHHP, a northerly shift of the ITCZ is postulated, thus confirming earlier results from the southern Arabian Peninsula.  相似文献   

M. CHAICHIAN,N.F. NELIPA: Introduction to Gauge Field Theories. Texts and Monographs in Physics. Springer-Verlag Berlin-Heidelberg-New York-Tokyo, 1984. XII + 332 Seiten,Preis: DM 112.— approx. US $ 40.80. ISBN 3-540-13008-X     

H. Fuchs 《Astronomische Nachrichten》1986,307(3):200-200

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Secular Post-NEWTONian Effects for the Restricted Three-Body Problem in TREDER'S Dynamics with Induced Inertia     

H. Fuchs 《Astronomische Nachrichten》1979,300(5):239-242

In the framework of TREDER'S dynamics, in which according to the MACH -EINSTEIN -doctrin the inertial masses are induced by the gravitational interaction with the particles of the cosmos, we calculate the secular post-NEWTON ian effects for the restricted three-body problem. The dominant secular post-NEWTON ian variation of nodes and apsides is shown to be the same as in EINSTEIN'S theory of gravitation. The formulation of the gravodynamics in the HERTZ ian configuration space allows – as in General Relativity – the explanation of the effect as an “geodetic precession” of the lines of nodes and apsides.  相似文献   

Seismic anisotropy of the subcrustal lithosphere as evidence for dynamical processes in the upper mantle   总被引：4，自引：0，他引：4  

K. Fuchs 《Geophysical Journal International》1977,49(1):167-179

Summary. Anisotropy of seismic waves in the uppermost mantle has not only been observed in the oceanic but recently also in the continental lithosphere. Laboratory experiments on the formation of preferred orientation of olivine crystals suggest plastic flow às the most likely mechanism for the genesis of anisotropy in the upper mantle. Since the direction of maximum velocity correlates in the ocean and on the continent with a number of tectonic features, a causal connection between anisotropy and dynamical processes related to plate motions must be suspected.  相似文献   

1. Alfred-Wegener-Conference on geophysical,geochemical and petrological evidence on deformation and composition of the continental subcrustal lithosphere     

K. Fuchs 《GeoJournal》1983,7(1):89-91

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Conflicts between explicit and implicit population distribution policies in Asian development plans     

Fuchs RJ 《Population geography : a journal of the Association of Population Geographers of India》1981,3(1-2):41-56

Conflicts between explicit and implicit population distribution policies in Asian development plans are examined. Various implicit policies and their possible consequences for spatial distribution are discussed. The development plans of China and Thailand are analyzed with particular attention to population distribution goals, the principal explicit policies aimed at promoting those goals, and the implicit policies that might conflict with explicit goals.  相似文献   

On the use of collocation methods for the construction of stellar models     

Richard L. Smith  Hans Fuchs 《Astrophysics and Space Science》1977,50(1):63-73

Collocation with piecewise continuous polynomials is studied for use in the numerical modelling of stellar evolution. Accuracy and convergence of the method are demonstrated for a 5M star with a convective core. Collocation should be further studied since it is likely to lead to significant gains in computational efficiency for the construction of stellar models.  相似文献   

Paleolimnological features of a mega-lake phase in the Makgadikgadi Basin (Kalahari,Botswana) during Marine Isotope Stage 5 inferred from diatoms     

Mareike Schmidt  Markus Fuchs  Andrew C. G. Henderson  Annette Kossler  Melanie J. Leng  Anson W. Mackay  Elisha Shemang  Frank Riedel 《Journal of Paleolimnology》2017,58(3):373-390

The Makgadikgadi–Okavango–Zambezi basin (MOZB) is a structural depression in the south-western branch of the East African Rift System of the northern and middle Kalahari, central southern Africa. In the present day, the mainly dry subbasins of the MOZB are part of a long-lived lacustrine system that has likely existed since Early Pleistocene and from which an extant freshwater fish radiation emerged seeding all major river systems of southern Africa. During hydrologically favourable periods the subbasins were connected as a single mega-lake termed Lake Palaeo-Makgadikgadi. Previous geomorphological studies and OSL dates have provided evidence for repeated mega-lake periods since approximately 300 ka. The environmental and climatic implications of such large scale late Quaternary lake-level fluctuations are controversial, with the duration of mega-lake phases poorly constrained. Here, we present the first evidence for a Marine Isotope Stage (MIS) 5 mega-lake period (about 935–940 m a.s.l.) reconstructed from a diatom-rich, 30-cm-thick lacustrine sediment section, exposed close to a palaeo-shoreline of the Makgadikgadi Basin. Based upon the environmental setting and in comparison with sedimentation rates of other similar lake environments, we tentatively estimated that the highstand lasted approximately 1 ka during MIS 5d–b. The 30-cm section was sampled in 0.5-cm steps. Diatom species diversity ranges from 19 to 30 through the section. The dominant species are Pseudostaurosira brevistriata, Rhopalodia gibberula, Cyclotella meneghiniana and Epithemia sorex. The total of 60 sediment samples provide us with a record at decadal to bi-decadal resolution. Based on diatom assemblages and their oxygen isotope composition (δ¹⁸O) we infer an alkaline and mostly oligohaline lake with shallow water conditions prevailing in MIS 5, and is potentially analogous to a Heinrich event. The climate over southern Africa during MIS 5 has been considered very arid but the hydromorphological context of our sediment section indicates that we captured a mega-lake period providing evidence that short-term excursions to significantly higher humidity existed. A hydrologically more favourable environment during MIS 5 than formerly presumed is in line with the early human occupation of the Kalahari.  相似文献   

Rockfall in the Port Hills of Christchurch: Seismic and non‐seismic fatality risk on roads          下载免费PDF全文

Stefan Unterrader  Peter Almond  Sven Fuchs 《New Zealand geographer》2018,74(1):3-14

Numerous rockfalls released during the 2010–2011 Canterbury earthquake sequence affected vital road sections for local commuters. We quantified rockfall fatality risk on two main routes by adapting a risk approach for roads originally developed for snow avalanche risk. We present results of the collective and individual fatality risks for traffic flow and waiting traffic. Waiting traffic scenarios particularly address the critical spatial‐temporal dynamics of risk, which should be acknowledged in operational risk management. Comparing our results with other risks commonly experienced in New Zealand indicates that local rockfall risk is close to tolerability thresholds and likely exceeds acceptable risk.  相似文献