New insights into Southern Caucasian glacial–interglacial climate conditions inferred from Quaternary gastropod fauna     

Christiane Richter  Daniel Wolf  Frank Walther  Stefan Meng  Lilit Sahakyan  Hayk Hovakimyan  Tilmann Wolpert  Markus Fuchs  Dominik Faust 《第四纪科学杂志》2020,35(5):634-649

In the present study, we performed gastropod analyses on loess–palaeosol sequences from northeast Armenia (Southern Caucasia) covering at least three glacial–interglacial cycles. The elaborated ecostratigraphy shows significant patterns of species composition related to the succession of pedocomplexes and loess, respectively. Pedocomplexes included species that can be associated with high-grass to forest-steppe biomes, indicating increased humidity for these sections compared to the loess layers. In contrast, loess layers that relate to glacial periods are associated with gastropod species of semidesert environments with shrub- and shortgrass-steppes, indicating semiarid to arid conditions. Furthermore, the loess deposits do not show any evidence for cold-adapted gastropod species. Therefore, we suggest that average July temperatures in the study area were above 10 °C, even during periods of loess deposition. Consequently, we propose that the limiting factor for tree growth during glacial periods was aridity, rather than temperature. In addition, we observe environmental differences between the various glacial times, with our results indicating a trend towards steadily increasing aridity in Southern Caucasia across the Middle to Late Pleistocene.  相似文献   

Integrating structural geology and petroleum systems modeling – A pilot project from Bolivia's fold and thrust belt     

Friedemann Baur  Matias Di Benedetto  Thomas Fuchs  Carolyn Lampe  Simone Sciamanna 《Marine and Petroleum Geology》2009

For the first time, a new approach to petroleum systems analysis is presented which allows full integration of tectonic and palinspastic restoration with three-dimensional (3D), PVT-controlled, multi-component, three-phase petroleum migration analysis through time. A systematic modeling study has been applied to a study area dominated by fold and thrust belts located in the Sub Andean orogeny near Tarija, Bolivia. The project has been performed with a special focus on the simulation technique and on the correct distribution of temperature, source-rock maturity and pressure development through time with reference to its input data. This is the first pilot project presenting a 3D numerical model in a compressional structural regime to which the basin modeling approach has been applied to explain the observed distribution of temperature, pressure, maturity and petroleum accumulations in general.  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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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   

The loess sequence of Dolní Věstonice,Czech Republic: A new OSL‐based chronology of the Last Climatic Cycle     

Markus Fuchs  Sebastian Kreutzer  Denis‐Didier Rousseau  Pierre Antoine  Christine Hatté  France Lagroix  Olivier Moine  Caroline Gauthier  Jiri Svoboda  Lenka Lisá 《Boreas: An International Journal of Quaternary Research》2013,42(3):664-677

The Dolní Věstonice loess section in the Czech Republic is well known for its high‐resolution loess–palaeosol sequence of the last interglacial–glacial climatic cycle (Upper Pleistocene). The loess section is situated in a climatic transition zone between oceanic and continental climates and is therefore of great value in reconstructing past regional climate conditions and their interaction with climate systems, in particular that of the North Atlantic. Based on a combination of optically stimulated luminescence (OSL) ages, stratigraphic field observations and magnetic susceptibility measurements, a chrono‐climatic interpretation of the Dolní Věstonice loess section is presented. To establish a reliable Upper Pleistocene chronology, a quartz OSL approach was applied for equivalent dose (D_e) determination. Monomineralic quartz extracts of three distinct grain sizes, fine (4–11 μm), middle (38–63 μm) and coarse (90–200 μm), were used and compared. Within error limits, the calculated OSL ages are the same for the different grain sizes, and the OSL ages are in stratigraphic order. The established OSL chronology is in agreement with a Weichselian litho‐ and pedostratigraphy. The Dolní Věstonice loess section is characterized by four pedosedimentary subsequences. At the base of the profile, subsequence I is characterized by a distinct Early Glacial soil complex, OSL‐dated to c. 110 to 70 ka, representing one of the most complete records of environmental change in the European loess belt. Subsequence II is allocated to the Lower Pleniglacial and is characterized by laminated sandy loess. Middle Pleniglacial subsequence III is represented by a brown soil complex, and is followed by the uppermost subsequence IV, characterized by a thick body of laminated sandy loess, indicating strong wind activity and a high sedimentation rate of more than ～1 mm a^?1 during the Upper Pleniglacial. According to the OSL chronology, as well as to the sedimentological and palaeopedological investigations, it is likely that the sequence at Dolní Věstonice has recorded most of the climatic events expressed in the NGRIP δ¹⁸O reference record between 110 and 70 ka.  相似文献   

Comment on ‘Where are the halo stars?’     

Burkhard Fuchs  Hartmut Jahreiß 《New Astronomy》2002,7(8):541-542

We comment briefly on a recent paper by Fuhrmann which claims that about half of the sample of halo stars in the solar neighbourhood presented by Fuchs and Jahreiß [A&A 329 (1998) 81] are actually thick disc stars. By referring to star counts in the CADIS survey we argue that this is rather unlikely.  相似文献   

The search for the origin of the Local Bubble redivivus     

B. Fuchs  D. Breitschwerdt  M. A. de Avillez  C. Dettbarn  C. Flynn 《Monthly notices of the Royal Astronomical Society》2006,373(3):993-1003

We present a new unbiased search and analysis of all B stars in the solar neighbourhood (within a volume of 400 pc diameter) using the Arivel data base to track down the remains of the OB associations, which hosted the supernovae (SNe) responsible for the Local Bubble (LB) in the interstellar gas. We find after careful dereddening and by comparison with theoretical isochrones, that besides the Upper Scorpius the Upper Centaurus Lupus and Lower Centaurus Crux subgroups are the youngest stellar associations in the solar neighbourhood with ages of 20–30 Myr, in agreement with previous work. In search for the 'smoking gun' of the origin of the LB, we have traced the paths of the associations back into the past and found that they entered the present bubble region 10–15 Myr ago. We argue that the LB began to form then and estimate that 14–20 SNe have gone off since. It is shown that the implied energy input is sufficient to excavate a bubble of the presently observed size.  相似文献