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31.
An improved, iteratively re‐weighted factor analysis procedure is presented to interpret engineering geophysical sounding logs in shallow unsaturated sediments. We simultaneously process cone resistance, electric resistivity, and nuclear data acquired by direct‐push tools to give robust estimates of factor variables and water content in unconsolidated heterogeneous formations. The statistical procedure is based on the iterative re‐weighting of the deviations between the measured and calculated data using the most frequent value method famous for its robustness and high statistical efficiency. The iterative approach improves the result of factor analysis for not normally distributed data and extremely noisy measurements. By detecting a strong regression relation between one of the extracted factors and the fractional volume of water, we establish an independent method for water content estimation along the penetration hole. We verify the estimated values of water volume by using a highly over‐determined, quality‐checked interval inversion procedure. The multidimensional extension of the statistical method allows the estimation of water content distribution along both the vertical and the horizontal coordinates. Numerical tests using engineering geophysical sounding data measured in a Hungarian loessy–sandy formation demonstrate the feasibility of the most frequent value‐based factor analysis, which can be efficiently used for a more reliable hydrogeophysical characterisation of the unsaturated zone. 相似文献
32.
Kálmán Török Bianka Németh Friedrich Koller Júlia Dégi Eszter Badenszki Csaba Szabó Aberra Mogessie 《Mineralogy and Petrology》2014,108(1):33-47
Felsic to mafic granulite xenoliths from late Neogene basalt pyroclastics in four localities of the western Pannonian Basin (Beistein, Kapfenstein, Szigliget and Káptalantóti (Sabar-hegy) were studied to find out their metamorphic and fluid history. The characteristic mineral assemblage of the granulites consists of Pl + Opx + Qtz ± Cpx ± Bt ± Grt ± Kfs. Based on abundant magmatic relic microstructural domains occurring in these rocks, the potential precursors might have been predominantly felsic igneous or high to ultrahigh temperature rocks. Ternary feldspar thermometry provides a rough estimate of temperatures of about 920–1070 °C. The first fluid invasion event, which is linked with this early high to ultrahigh temperature stage is characterised by primary pure CO2 inclusions in apatite and zircon. The densest primary CO2 inclusions indicate 0.52–0.64 GPa pressure at the estimated temperature range of crystallization. According to mineral equilibria and geothermobarometry, the high to ultrahigh temperature rock cooled and crystallized to granulite of predominantly felsic composition at about 750–870 °C and 0.50–0.75 GPa in the middle crust, between 20 and 29 km depths. The second fluid invasion event is recorded by primary CO2-rich fluid inclusions hosted in the granulitic mineral assemblage (plagioclase, quartz and orthopyroxene). In addition to CO2, Raman spectroscopy revealed the presence of minor N2, H2S, CO and H2O in these inclusions. Partial melting of biotite-bearing assemblages could be connected to the next fluid invasion shown by secondary CO2-rich fluids recorded along with healed fractures in plagioclase, clinopyroxene and orthopyroxene. This event could have happened at depths similar to the previous ones. The final step in the granulite evolution was the sampling in the middle crust and transportation to the surface in form of xenoliths by mafic melt. This event generated temperature increase and pressure decrease and thus, limited melting of the xenoliths. The youngest fluid inclusion generation, observed mostly in healed fractures of felsic minerals, could be associated with this event. 相似文献
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34.
Norbert P. Szabó 《Acta Geophysica》2011,59(5):935-953
In the paper factor analysis is applied to well-logging data in order to extract petrophysical information about sedimentary
structures. Statistical processing of well logs used in hydrocarbon exploration results in a factor log, which correlates
with shale volume of the formations. The so-called factor index is defined analogously with natural gamma ray index for describing
a linear relationship between one special factor and shale content. Then a general formula valid for a longer depth interval
is introduced to express a nonlinear relationship between the above quantities. The method can be considered as an independent
source of shale volume estimation, which exploits information inherent in all types of well logs being sensitive to the presence
of shale. For demonstration, two wellbore data sets originated from different areas of the Pannonian Basin of Central Europe
are processed, after which the shale volume is computed and compared to estimations coming from independent inverse modeling. 相似文献
35.
Multiple provenance of detrital zircons from the Permian–Triassic boundary in the Bükk Mts., Hungary
Norbert Zajzon Zsófia Szabó Tamás Gábor Weiszburg Teresa Elizabeth Jeffries 《International Journal of Earth Sciences》2011,100(1):125-138
Detailed zircon analyses were carried out on samples from the Bálvány North section, which contains the Permian–Triassic boundary.
A fine-grained sandstone bed within the “boundary shale” contains a significant amount of zircon crystals. Pupin morphological,
scanning electron microscopy [secondary electron, back-scattered electron, cathodoluminescence (CL)] and laser ablation inductively
coupled mass spectrometry (LA-ICP-MS) investigations were done in selected single grains to combine morphological information
with radiometric ages, and infer the provenance of zircons. Three populations are distinguished on the basis of Pupin morphology.
Their centres of gravity are S17, S2 and P1. The LA-ICP-MS radiometric ages reveal three main age groups and a smaller one,
apart from a few scattered old ages. The largest group, comprising ca. 50% of the measured grains, has an age of 470–440 Ma.
The two other main groups, which together represent ca. 25% of the measured grains, are around 280 and 600 Ma. The 280 Ma
group contains slightly more grains than the 600 Ma group. A small group has an age of 370–340 Ma. In addition, there are
some older grains with ages of 850, 969, 1,050 and 2,150 Ma. Based on the zircon morphology no clear separation of the different
age groups could be made. Both the 280 Ma and the 470–440 Ma age groups tend to show zircon crystals derived from three types
of sources: crustal granites, calc-alkaline granitoids and alkali granites and/or their volcanic equivalents. Zircons in the
450 Ma group have a magmatic rim around their altered, relict core, as revealed by CL images. Post-magmatic processes also
affected the rim. The age of the core is possibly reset during the formation of the magmatic rim. This suggestion is supported
by the LA-ICP-MS data, because no difference was seen between the core and the rim. The different roundness of the zircons,
the well-sorted crystals and the at least five different source rocks indicate previous concentration of the grains, before
their transportation into the “boundary shale”. Austroalpine and Southern Alpine rocks could be the sources of the zircon
crystals, which fit well into the paleogeographical model of the area, which suggests that the Bükk Mts. was located in the
foreground of the Alpine units. 相似文献
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Gyula M. Szabó Giannantonio Milani Carlo Vinante Rolando Ligustri Giovanni Sostero Roberto Trabatti 《Earth, Moon, and Planets》2010,107(2-4):253-265
We have launched the Cometary Archives for Amateur Astronomers, CARA, aiming at coordinated collection of homogeneous, long-time based, continuous data set of bright comet observations. The project is based on a collaboration between professional and amateur astronomers. The archived quantity is a set of the photometric Afρ, measured in I, R or red continuum 647/10 nm filters. To derive coma profiles, Afρ is measured in at least different radii selected from a set of 50,000, 25,000, 12,500, 6,000 and 3,000 km. The data are free to download for registered users, special requests are available upon personal contact. We also provide aspecific code with a tutorial for the aperture photrometry of comets. The purpose of this paper is to introduce the observing methods, tools, software supports and web resources of project CARA. 相似文献
38.
The shape of sedimentary particles may carry important information on their history. Current approaches to shape classification
(e.g. the Zingg or the Sneed and Folk system) rely on shape indices derived from the measurement of the three principal axes
of the approximating tri-axial ellipsoid. While these systems have undoubtedly proved to be useful tools, their application
inevitably requires tedious and ambiguous measurements, also classification involves the introduction of arbitrarily chosen
constants. Here we propose an alternative classification system based on the (integer) number of static equilibria. The latter
are points of the surface where the pebble is at rest on a horizontal, frictionless support. As opposed to the Zingg system,
our method relies on counting rather than measuring. We show that equilibria typically exist on two well-separated (micro
and macro) scales. Equilibria can be readily counted by simple hand experiments, i.e. the new classification scheme is practically
applicable. Based on statistical results from two different locations we demonstrate that pebbles are well mixed with respect
to the new classes, i.e. the new classification is reliable and stable in that sense. We also show that the Zingg statistics
can be extracted from the new statistics; however, substantial additional information is also available. From the practical
point of view, E-classification is substantially faster than the Zingg method. 相似文献
39.
István Kovács Attila Demény György Czuppon Christophe Lécuyer Francois Fourel Qun-Ke Xia Jia Liu Zsanett Pintér Edit Király Kálmán Török Ábel Szabó Etienne Deloule György Falus Tamás Fancsik Zoltán Zajacz Judit Sándorné Kovács Beatrix Udvardi 《Contributions to Mineralogy and Petrology》2016,171(5):38
40.
The aim of this paper was to analyze the ground and low vegetation points of a Light Detection and Ranging (LiDAR) point cloud from the aspect of the generated digital terrain model (DTM). We determined the height difference between the surveyed surface and the DTM and the level of interspersion of ground and low vegetation points in a floodplain. Finally, we performed a supervised classification with topographic (elevation, slope and aspect) variables and an Normalized Difference Vegetation Index (NDVI) layer to identify swales and point bars as floodplain forms. Cross sections of field surveys provided reference data to express the magnitude of the bias on the DTM caused by the vegetation, and we proved that the bias can reach the 60% of the relative height and depth of the floodplain forms (mean error was 0.15 ± 0.12 m). A landscape metric, the Aggregation Index, provided an appropriate tool to analyze and quantify the interspersion of the ground and vegetation points: indicating a high level of interspersion of the classified points, i.e. proved that vegetation points where the last echoes reflected from the vegetation became ground points. Floodplain classification performed best with the common use of DTM, slope, aspect and NDVI coverages, with 71% overall accuracy. 相似文献