New chronology and extended palaeoenvironmental data to the 1975 loess profile of Madaras brickyard,South Hungary     

Pál Sümegi  Sándor Gulyás  Dávid Molnár  Gábor Bozsó  István Fekete  László Makó  Péter Cseh  Mihály Molnár  Balázs P. Sümegi  Peter Almond  Christian Zeeden  Tünde Törőcsik  Janina J. Nett  András Markó  Frank Lehmkuhl 《第四纪科学杂志》2021,36(8):1364-1381

The 10 m thick Madaras loess–palaeosol profile is one of the Hungarian outcrops that yielded Upper Palaeolithic artefacts in 1966. To clarify the nature of the deposits and establish a reliable litho- and chronostratigraphy, a profile was opened and sampled at 25 cm intervals on the northern side of the brickyard in 1975. Analyses focused on grain size, carbonate content and the mollusc fauna. The chronology was based on the mollusc composition and a single date from the archaeological layer at the depth of ca 7 m below the surface. The 1975 profile was destroyed by mining but the reposited samples allowed an extended analysis of this important Marine Isotope Stage 2 record to which archaeological features were directly assigned. A new absolute chronology was built based on 11 ¹⁴C dates. Environmental magnetic, geochemical and palaeoecological investigations allowed a refined view of site evolution with reliable chronology for the Last Glacial Maximum. Our results corroborated those of previous investigations done on other coeval loess–palaeosol sequences of the Southern Carpathian Basin. This also allowed for a temporal correlation to another local record with the published high-resolution chronology of the same brickyard and enabled modelling of local-scale heterogeneity of the environment in the long run.  相似文献   

Geochemistry of the earth's surface edited by H. Ármannsson,Balkema, Rotterdam, 1999. No. of pages: 574. Price: $125, ?81. ISBN 90 5809 073 6.     

A. Rosell‐Mel 《地球表面变化过程与地形》2001,26(3):343-343

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Numerical model and dynamic analysis of multi degree of freedom masonry arches     

László P. Kollár  Tamás Ther 《地震工程与结构动力学》2019,48(7):709-730

A new model is presented for planar multi-block arches subjected to earthquakes. The blocks are assumed to be rigid, and every interface between the blocks may split open and may close, ie, the blocks may impact to each other. During impact, both the classical Housner's approach and improved models with lower energy dissipation are considered. The arch model is verified by comparisons with the available results in the literature. Using the new model, it was found that the circular arch moves as a four-hinge mechanism typically only at the beginning of excitation, and several cracks split open during motion; furthermore, that modeling a multi-block arch by a single degree of freedom (SDOF) four-hinge mechanism may significantly overestimate its collapse load. While, in accordance with the literature, the overturning curves of single blocks and arches with symmetrically located four hinges are similar; for multi-block arches where several hinges may occur they can be very different.  相似文献   

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   

Land cover classification of VHR airborne images for citrus grove identification     

J. Amorós López  E. Izquierdo VerdiguierL. Gómez Chova  J. Muñoz MaríJ.Z. Rodríguez Barreiro  G. Camps VallsJ. Calpe Maravilla 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(1):115-123

Managing land resources using remote sensing techniques is becoming a common practice. However, data analysis procedures should satisfy the high accuracy levels demanded by users (public or private companies and governments) in order to be extensively used. This paper presents a multi-stage classification scheme to update the citrus Geographical Information System (GIS) of the Comunidad Valenciana region (Spain). Spain is the first citrus fruit producer in Europe and the fourth in the world. In particular, citrus fruits represent 67% of the agricultural production in this region, with a total production of 4.24 million tons (campaign 2006-2007). The citrus GIS inventory, created in 2001, needs to be regularly updated in order to monitor changes quickly enough, and allow appropriate policy making and citrus production forecasting. Automatic methods are proposed in this work to facilitate this update, whose processing scheme is summarized as follows. First, an object-oriented feature extraction process is carried out for each cadastral parcel from very high spatial resolution aerial images (0.5 m). Next, several automatic classifiers (decision trees, artificial neural networks, and support vector machines) are trained and combined to improve the final classification accuracy. Finally, the citrus GIS is automatically updated if a high enough level of confidence, based on the agreement between classifiers, is achieved. This is the case for 85% of the parcels and accuracy results exceed 94%. The remaining parcels are classified by expert photo-interpreters in order to guarantee the high accuracy demanded by policy makers.  相似文献   

Mineralogy,diagenesis and hydrochemical evolution in a probertite–glauberite–halite saline lake (Miocene,Emet Basin,Turkey)     

Javier García-Veigas  Laura Rosell  Federico Ortí  İbrahim Gündoğan  Cahit Helvacı 《Chemical Geology》2011,280(3-4):352-364

The Emet basin is one of the Neogene basins in western Turkey containing significant amounts of borate minerals, mainly colemanite. The petrologic study of core samples from two exploratory wells in the Do?anlar sector, under optic and electron microscopy, reveals a complex mineral association in which probertite, glauberite, and halite constitute the major primary phases (without mineral precursors) precipitated in a saline lake placed in a volcano-sedimentary context. Other sulfates (anhydrite, gypsum, thenardite, celestite and kalistrontite), borates (colemanite, ulexite, hydroboracite, tunellite, kaliborite and aristarainite), and sulfides (arsenopyrite, realgar and orpiment) are attributed to early diagenesis. So far, the Do?anlar deposit is the most important deposit of probertite known up to now.Chemical changes in the groundwater inflow led to the precipitation of Ca-bearing borates (colemanite) in the tuff-flat environment surrounding the lake, while Na–Ca sulfates and borates (glauberite and probertite) precipitated in the center of the lake. Fluid inclusion compositions in halite indicate that the advanced brines correspond to the Na-K-Cl-SO₄ type. During restricted stages of the saline lake, the residual brines seeped through the tuff-flat sediments, leading to transformations of previous precipitates that resulted in the formation of K-bearing minerals.The abundance of coccoid-like biogenic dolomite, colloidal arsenopyrite and the isotopic composition of sulfates are indicative of bacterial sulfate reduction. In contrast, arsenic sulfides are attributed to acidophilic micro-organisms in oxidizing conditions. Fluctuations of redox conditions in both free and interstitial brines control the biological influence in some diagenetic transformations.  相似文献   

Factors controlling the morphology and volume (V)–length (L) relations of permanent gullies in the northern Ethiopian Highlands     

Amaury Frankl  Jean Poesen  Nelles Scholiers  Miró Jacob  Mitiku Haile  Jozef Deckers  Jan Nyssen 《地球表面变化过程与地形》2013,38(14):1672-1684

Small‐scale aerial photographs and high‐resolution satellite images, available for Ethiopia since the second half of the twentieth century as for most countries, allow only the length of gullies to be determined. Understanding the development of gully volumes therefore requires that empirical relations between gully volume (V) and length (L) are established in the field. So far, such V–L relations have been proposed for a limited number of gullies/environments and were especially developed for ephemeral gullies. In this study, V–L relations were established for permanent gullies in northern Ethiopia, having a total length of 152 km. In order to take the regional variability in environmental characteristics into account, factors that control gully cross‐sectional morphology were studied from 811 cross‐sections. This indicated that the lithology and the presence of check dams or low‐active channels were the most important controls of gully cross‐sectional shape and size. Cross‐sectional size could be fairly well predicted by their drainage area. The V–L relation for the complete dataset was V = 0 · 562 L ^1·381 (n = 33, r² = 0 · 94, with 34 · 9% of the network having check dams and/or being low‐active). Producing such relations for the different lithologies and percentages of the gully network having check dams and/or being low‐active allows historical gully development from historical remote sensing data to be assessed. In addition, gully volume was also related to its catchments area (A) and catchment slope gradient (S_c). This study demonstrates that V–L and V–A × S_c relations can be very suitable for planners to assess gully volume, but that the establishment of such relations is necessarily region‐specific. Copyright © 2013 John Wiley & Sons, Ltd.  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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Deep electrical resistivity structure of the northern Gibraltar Arc (western Mediterranean): evidence of lithospheric slab break‐off     

Oriol Rosell  Anna Martí  Àlex Marcuello  Juanjo Ledo  Pilar Queralt  Eduard Roca  Joan Campanyà 《地学学报》2011,23(3):179-186

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Geochemical controls on leaching of lignite-fired combustion by-products from Greece     

Maria Izquierdo  Nikolaos Koukouzas  Sofia Touliou  Kyriakos D. Panopoulos  Xavier Querol  Grigorios Itskos 《Applied Geochemistry》2011,26(9-10):1599-1606

The mobility of inorganic pollutants is of key concern for a range of industrial and engineering applications of fly ash produced during the combustion of lignite in power generation. This paper investigates the role that the geochemical features of lignite, the ash composition and the partitioning of elements during combustion play in determining leaching properties of lignite fired by-products. The work is based on surveys on three lignite-fired power plants in Greece. Calcium-rich ashes show a high abatement potential for SO₂ and other gaseous pollutants. For most elements, the concentrations in the parent lignite and the ashes follow the same trend. Relative enrichments in Cd, Co, Cr, Cu, Mo, Ni, Pb, U, V, W, Zn fingerprint the regional and local geological settings of the lignite basins. The total and leachable concentrations of highly volatile elements are strongly influenced by the interaction with ubiquitous free lime. A broad array of elements is highly insoluble in alkaline ash, while a few oxyanionic-forming elements display substantial mobility. Their mode of occurrence in the parent lignite plays a primary role in the leaching of combustion ashes. The outcomes of this study may assist in addressing the impact of co-firing high ash or high Ca alternative fuels on the leaching properties of combustion by-products.  相似文献