Obliquity-driven mountain permafrost-related fluvial magnetic susceptibility cycles in the Quaternary mid-latitude long-term (2.5 Ma) fluvial Maros Fan in the Pannonian Basin     

Zoltán Püspöki  Philip L. Gibbard  László Ferenc Kiss  Richard W. McIntosh  Edit Thamó-Bozsó  Zita Krassay  Bálint Szappanos  Vera Maigut  Péter Kovács  Dominik Karácsony  Ferenc Stercel  Ferenc Visnovitz  Krisztina Demény  László Bereczki  Teodóra Szőcs  Ágnes Rotár-Szalkai  Tamás Fancsik 《Boreas: An International Journal of Quaternary Research》2023,52(3):402-426

Magnetic susceptibility (MS) of the Quaternary long-term mid-latitude Maros fluvial fan (Pannonian Basin) was recorded to understand the stratigraphical features of source-proximal fluvial depositional settings. Three fully cored 500-m-deep boreholes were sampled at 0.5-m intervals; low-field and frequency dependent MS were measured, and complementary hysteresis and SEM-EDAX investigations were performed on selected samples. Logged susceptibility data were also used to log correlations established by a simultaneous comparison of wireline log and laboratory measurements. Time-series analyses of the susceptibility records reveal a ~41-ka and ~100-ka cyclicity. Towards the source-distal sections the intensity of the ~41-ka cycles decreases, while that of the ~100-ka cycles remains strong. Stratigraphical and spectral similarities were observed between the Maros fluvial fan and Chinese loess records; however, based on complementary magnetic data, the magnetic phase of the Maros Fan sections is related to the detrital magnetite that originates from the catchment during early postglacial permafrost degradations. The amplification of the ~41-ka cycles can be attributed to the very high susceptibility values in source-proximal settings and to the special stratigraphical feature of the distributive fluvial systems. This comprises the increased avulsion frequency on the fluvial fans in ‘glacial recession periods’, in concert with the ‘early postglacial’ occurrence of the permafrost-related magnetite originating from the catchment. As a local phenomenon, this is significant since it records the obliquity-driven variations in permafrost development in a catchment. However, fluvial and alluvial fans are widespread depositional landforms within the Eurasian mountain range and were possibly the same during the Quaternary deglaciations. Thus, obliquity-driven magnetic susceptibility variations in source-proximal fan deposits attached or adjacent to regions of loess deposition should also be considered when scanning for potential source material of aeolian deposits.  相似文献   

Normal modes of synchronous rotation     

Ferenc Varadi  Susanna Musotto  William Moore  Gerald Schubert 《Icarus》2005,176(1):235-249

The dynamics of synchronous rotation and physical librations are revisited in order to establish a conceptually simple and general theoretical framework applicable to a variety of problems. Our motivation comes from disagreements between the results of numerical simulations and those of previous theoretical studies, and also because different theoretical studies disagree on basic features of the dynamics. We approach the problem by decomposing the orientation matrix of the body into perfectly synchronous rotation and deviation from the equilibrium state. The normal modes of the linearized equations are computed in the case of a circular satellite orbit, yielding both the periods and the eigenspaces of three librations. Libration in longitude decouples from the other two, vertical modes. There is a fast vertical mode with a period very close to the average rotational period. It corresponds to tilting the body around a horizontal axis while retaining nearly principal-axis rotation. In the inertial frame, this mode appears as nutation and free precession. The other vertical mode, a slow one, is the free wobble. The effects of the nodal precession of the orbit are investigated from the point of view of Cassini states. We test our theory using numerical simulations of the full equations of the dynamics and discuss the disagreements among our study and previous ones. The numerical simulations also reveal that in the case of eccentric orbits large departures from principal-axis rotation are possible due to a resonance between free precession and wobble. We also revisit the history of the Moon's rotational state and show that it switched from one Cassini state to another when it was at 46.2 Earth radii. This number disagrees with the value 34.2 derived in a previous study.  相似文献   

Capture in the Circular and Elliptic Restricted Three-Body Problem     

Zoltán Makó  Ferenc Szenkovits 《Celestial Mechanics and Dynamical Astronomy》2004,90(1-2):51-58

In this paper the authors provide a study of the phenomenon of the gravitational capture by using the models of the circular and elliptic restricted three-body problem. In the first part the inadequacy of the circular restricted three-body problem in the study of the phenomenon of the capture in the case of NEAs is shown. In the model of the spatial elliptic restricted three-body problem criteria of the capture are deduced by using the pulsating Hill-regions. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Origin and weathering of landslide material in a loess area: a geochemical study of the Kulcs landslide,Hungary     

Beatrix Udvardi  István János Kovács  Csaba Szabó  György Falus  Gábor Újvári  Anikó Besnyi  Éva Bertalan  Ferenc Budai  Zsolt Horváth 《Environmental Earth Sciences》2016,75(19):1299

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Association of gold with uraninite and pyrobitumen in the metavolcanic rock hosted hydrothermal Au-U mineralisation at Rompas,Peräpohja Schist Belt,northern Finland     

Ferenc Molnár  Harry Oduro  Nick D. J. Cook  Esa Pohjolainen  Ágnes Takács  Hugh O’Brien  Lassi Pakkanen  Bo Johanson  Richard Wirth 《Mineralium Deposita》2016,51(5):681-702

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Stable and unstable orbits around Mercury     

Zoltán Makó  Ferenc Szenkovits  Júlia Salamon  Robert Oláh-Gál 《Celestial Mechanics and Dynamical Astronomy》2010,108(4):357-370

This paper provides a study of the stable and unstable regions around the smaller primary in the framework of the spatial elliptic restricted three-body problem. The definitions and methods used to determine stable and unstable regions are extended to three dimensions. New results concerning the stable and unstable regions around Mercury are obtained in the Sun–Mercury system.  相似文献   

Multiobjective analysis of a public wellfield using artificial neural networks   总被引：3，自引：0，他引：3  

Coppola EA  Szidarovszky F  Davis D  Spayd S  Poulton MM  Roman E 《Ground water》2007,45(1):53-61

As competition for increasingly scarce ground water resources grows, many decision makers may come to rely upon rigorous multiobjective techniques to help identify appropriate and defensible policies, particularly when disparate stakeholder groups are involved. In this study, decision analysis was conducted on a public water supply wellfield to balance water supply needs with well vulnerability to contamination from a nearby ground water contaminant plume. With few alternative water sources, decision makers must balance the conflicting objectives of maximizing water supply volume from noncontaminated wells while minimizing their vulnerability to contamination from the plume. Artificial neural networks (ANNs) were developed with simulation data from a numerical ground water flow model developed for the study area. The ANN-derived state transition equations were embedded into a multiobjective optimization model, from which the Pareto frontier or trade-off curve between water supply and wellfield vulnerability was identified. Relative preference values and power factors were assigned to the three stakeholders, namely the company whose waste contaminated the aquifer, the community supplied by the wells, and the water utility company that owns and operates the wells. A compromise pumping policy that effectively balances the two conflicting objectives in accordance with the preferences of the three stakeholder groups was then identified using various distance-based methods.  相似文献   

Loss of 40Ar(rad) from leucite-bearing basanite at low temperature: implications on K/Ar dating.     

Kadosa Balogh  Károly Németh  Tetsumaru Itaya  Ferenc Molnár  Robert Stewart  Ngo X. Thanh  Hironobu Hyodo  Lajos Daróczi 《Central European Journal of Geosciences》2010,2(3):385-398

The Bakony-Balaton Highland Volcanic Field (BBHVF) is located in the central part of Transdanubia, Pannonian Basin, with over 50 alkali basaltic volcanoes. The basanite plug of Hegyestu erupted in the first phase of volcanic activity. K/Ar and Ar/Ar ages were published for the BBHVF. K/Ar and Ar/Ar ages of the leucite-bearing basanite of Hegyestás were conflicting. This is caused by the special Ar retention feature of leucite in this basanite. K/Ar ages measured in the usual way were 25–45% younger, but after HCl treatment of the rock, or after reducing the baking temperature of the argon extraction line from 250°C to 150°C, they became similar to the Ar/Ar ages. All Ar/Ar determinations were performed after HF treatment. HCl treatment dissolved olivine, nepheline, leucite, magnetite and from 1-1 sample analcime or calcite. K dissolution studies from different locations of Hegyestü have shown that K content is mostly ≈2%, but it may decrease to ≈0.3%. HCl treatment dissolved 28.0–63.5% of the K content. The calculated K concentration for the dissolved part of samples with ~2%K was 4.02-6.42%: showing that leucite is responsible for the low temperature loss of ⁴⁰Ar(rad). Ar may release at low temperature from very finegrained mineral, or when the Ar release mechanism changes. A ⁴⁰Ar(rad) degassing spectrum has been recorded in the 55–295°C range of baking temperature and the data were plotted in the Arrhenius diagram. The diagram shows that a change of the structure in the 145–295°C range caused the loss of ⁴⁰Ar(rad). On fractions of HCl treated rock 7.56±0.17 Ma isochron K/Ar age has been determined. This is regarded as minimum age of eruption and it is similar to the Ar/Ar isochron age (7.78±0.07 Ma).  相似文献   

Managing the inconceivable: participatory assessments of impacts and responses to extreme climate change     

Ferenc L. Toth  Eva Hizsnyik 《Climatic change》2008,91(1-2):81-101

A comprehensive understanding of the implications of extreme climate change requires an in-depth exploration of the perceptions and reactions of the affected stakeholder groups and the lay public. The project on “Atlantic sea level rise: Adaptation to imaginable worst-case climate change” (Atlantis) has studied one such case, the collapse of the West Antarctic Ice Sheet and a subsequent 5–6 m sea-level rise. Possible methods are presented for assessing the societal consequences of impacts and adaptation options in selected European regions by involving representatives of pertinent stakeholders. Results of a comprehensive review of participatory integrated assessment methods with a view to their applicability in climate impact studies are summarized including Simulation-Gaming techniques, the Policy Exercise method, and the Focus Group technique. Succinct presentations of these three methods are provided together with short summaries of relevant earlier applications to gain insights into the possible design options. Building on these insights, four basic versions of design procedures suitable for use in the Atlantis project are presented. They draw on design elements of several methods and combine them to fit the characteristics and fulfill the needs of addressing the problem of extreme sea-level rise. The selected participatory techniques and the procedure designs might well be useful in other studies assessing climate change impacts and exploring adaptation options.  相似文献   

Trends in planetary wave activity inferred from Hungarian radio wave absorption measurements     

Jan Lastovička  Ferenc Märcz 《Studia Geophysica et Geodaetica》1995,39(4):420-424

Summary The nighttime and sunset LF radio wave absorption measured at Nagycenk, western Hungary over 1967–1991 is used to infer planetary wave activity and its long-term trend in the upper middle atmosphere (85 – 100 km). The very moderate positive and mostly statistically insignificant trends are consistent with the pattern provided by previous analyses of various day- and night-time absorption measurements. The trends could be of anthropogenic origin.  相似文献