Radon variations in a Hungarian village     

E. Tóth  F. Deak  C. S. Gyurkócza  Z. S. Kasztovszky  R. Kuczi  G. Marx  B. Nagy  S. Oberstedt  L. Sajó-Bohus  C. S. Sükösd  G. Toth  N. Vajda 《Environmental Geology》1997,31(1-2):123-127

 A steady radon exhalation is assumed in most publications. In a village of North-East Hungary, however, high radon concentrations have been measured, differing strongly in neighbouring houses and varying in time, due to the interplay of geochemical phenomena. Received: 20 November 1995 · Accepted: 18 June 1996  相似文献   

Using Mesoproterozoic sedimentary geochemistry to reconstruct basin tectonic geography and link organic carbon productivity to nutrient flux from a Northern Australian large igneous Province     

Bo Yang  Alan S. Collins  Grant M. Cox  Amber J. M. Jarrett  Steven Denyszyn  Morgan L. Blades  Juraj Farkaš  Stijn Glorie 《Basin Research》2020,32(6):1734-1750

The Beetaloo Sub-basin, northern Australia, is considered the main depocentre of the 1,000-km scale Mesoproterozoic Wilton package of the greater McArthur Basin – the host to one of the oldest hydrocarbon global resources. The ca. 1.40–1.31 Ga upper Roper Group and the latest Mesoproterozoic to early Neoproterozoic unnamed group of the Beetaloo Sub-basin, together, record ca. 500 million years of depositional history within the North Australia Craton. Whole-rock shale Sm–Nd and Pb isotope data from these sediments reveal sedimentary provenance and their evolution from ca. 1.35 to 0.85 Ga. Furthermore, these data, together with shale major/trace elements data from this study and pyrolysis data from previous publications, are used to develop a dynamic tectonic geography model that links the organic carbon production and burial to an enhanced weathering of nutrients from a large igneous province. The ca. 1.35–1.31 Ga Kyalla Formation of the upper Roper Group is composed of isotopically evolved sedimentary detritus that passes up, into more isotopically juvenile Pb values towards the top of the formation. The increase in juvenile compositions coincides with elevated total organic carbon (TOC) contents of these sediments. The coherently enriched juvenile compositions and TOC the upper portions of the Kyalla Formation are interpreted to reflect an increase in nutrient supply associated with the weathering of basaltic sources (e.g. phosphorous). Possible, relatively juvenile, basaltic sources include the Wankanki Supersuite in the western Musgraves and the Derim Derim–Galiwinku large igneous province (LIP). The transition into juvenile, basaltic sources directly before a supersequence-bounding unconformity is here interpreted to reflect uplift and erosion of the Derim Derim–Galiwinku LIP, rather than an influx of southern Musgrave sources. A new baddeleyite crystallisation age of 1,312.9 ± 0.7 Ma provides both a tight constraint on the age of this LIP, along with its associated magmatic uplift, as well as providing a minimum age constraint for Roper Group deposition. The unconformably overlying lower and upper Jamison sandstones are at least 300 million years younger than the Kyalla Formation and were sourced from the Musgrave Province. An up-section increase in isotopically juvenile compositions seen in these rocks is interpreted to document the progressive exhumation of the western Musgrave Province. The overlying Hayfield mudstone received detritus from both the Musgrave and Arunta regions, and its isotopic geochemistry reveals affinities with other early Neoproterozoic basins (e.g. Amadeus, Victoria and Officer basins), indicating the potential for inter-basin correlations.  相似文献   

Effect of cofactors of adjusted and unadjusted quantities on their functions     

Juraj Šütti  Reviewer L. Kubáčková 《Studia Geophysica et Geodaetica》1984,28(1):11-18

aamuam uu am a (m u naamuu n) u u (a) uu a uu mu uu. mam (19), (28) naam, m amua am mau u m ¶rt; am amu: a) na ¶rt;um am, n n a uu am u uu a uu; ) ma ¶rt;um am, m aam uu a uu.  相似文献   

The effect of initial data in adjusting conditional observations     

Juraj Šütti  Reviewer J. Kašpar 《Studia Geophysica et Geodaetica》1973,17(2):100-105

Summary In the introduction the effect of neglecting the accuracy of the initial data is mentioned in adjusting conditional observations, because this essentially causes the accuracy of the adjusted quantities to be overrated. The effect of changes (errors) of the initial data is investigated for two cases: a) when the initial data are given, unmeasured quantities; b) when the initial data are given and measured quantities which form the conditions of adjustment (e.g., gyrotheodolite directional angles). This effect was rejected in a change of the corrections, in the vrst case according to (14), and in the second according to (18). The effect of the changes (errors) of the initial data was also investigated with regard to the matrix of the co-factors of the adjusted quantities. This matrix, taking into account the errors of the initial data described by matrixQww, and the errors of the measurements themselves, described by matrix (26), is expressed by (31).Dedicated to 90th Birthday of Professor Frantiek Fiala  相似文献   

Displacement of points determined by spatial intersection     

Juraj Šütti  Reviewer B. Delong 《Studia Geophysica et Geodaetica》1976,20(4):329-337

Summary A procprocedure is presented for the direct determination of the components of the vector of spatial displacement of a point by spatial intersection. The horizontal, vertical and slope distances are determined by integrated surveying systems (electronic tacheometers), and the first survey is adjusted using conditional observations. The vector of displacement on the individual intervals of observation is determined by means of the matrix equation (33) into which it is only necessary to substitute the appropriate vectors of the observational differences.  相似文献   

Oxygen and carbon isotope ratios in the martian atmosphere     

Vladimir A. Krasnopolsky  Jean Pierre Maillard  Tobias C. Owen  Robert A. Toth  Michael D. Smith 《Icarus》2007,192(2):396-403

Oxygen and carbon isotope ratios in the martian CO₂ are key values to study evolution of volatiles on Mars. The major problems in spectroscopic determinations of these ratios on Mars are uncertainties associated with: (1) equivalent widths of the observed absorption lines, (2) line strengths in spectroscopic databases, and (3) thermal structure of the martian atmosphere during the observation. We have made special efforts to reduce all these uncertainties. We observed Mars using the Fourier Transform Spectrometer at the Canada–France–Hawaii Telescope. While the oxygen and carbon isotope ratios on Mars were byproducts in the previous observations, our observation was specifically aimed at these isotope ratios. We covered a range of 6022 to 6308 cm⁻¹ with the highest resolving power of ν/δν=3.5×10⁵ and a signal-to-noise ratio of 180 in the middle of the spectrum. The chosen spectral range involves 475 lines of the main isotope, 184 lines of ¹³CO₂, 181 lines of CO¹⁸O, and 119 lines of CO¹⁷O. (Lines with strengths exceeding 10⁻²⁷ cm at 218 K are considered here.) Due to the high spectral resolution, most of the lines are not blended. Uncertainties of retrieved isotope abundances are in inverse proportion to resolving power, signal-to-noise ratio, and square root of the number of lines. Laboratory studies of the CO₂ isotope spectra in the range of our observation achieved an accuracy of 1% in the line strengths. Detailed observations of temperature profiles using MGS/TES and data on temperature variations with local time from two GCMs are used to simulate each absorption line at various heights in each part of the instrument field of view and then sum up the results. Thermal radiation of Mars' surface and atmosphere is negligible in the chosen spectral range, and this reduces errors associated with uncertainties in the thermal structure on Mars. Using a combination of all these factors, the highest accuracy has been achieved in measuring the CO₂ isotope ratios: ¹³C/¹²C = 0.978 ± 0.020 and ¹⁸O/¹⁶O = 1.018 ± 0.018 times the terrestrial standards. Heavy isotopes in the atmosphere are enriched by nonthermal escape and sputtering, and depleted by fractionation with solid-phase reservoirs. The retrieved ratios show that isotope fractionation between CO₂ and oxygen and carbon reservoirs in the solid phase is almost balanced by nonthermal escape and sputtering of O and C from Mars.  相似文献   

Heat capacity, entropy, and magnetic properties of jarosite-group compounds     

Juraj Majzlan  Peter Glasnák  Robert A. Fisher  Mary Anne White  Michel B. Johnson  Brian Woodfield  Juliana Boerio-Goates 《Physics and Chemistry of Minerals》2010,37(9):635-651

Jarosite phases are common minerals in acidic, sulfate-rich environments. Here, we report heat capacities (C _p) and standard entropies (S°) for a number of jarosite samples. Most samples are close to the nominal composition AFe₃(SO₄)₂(OH)₆, where A = K, Na, Rb, and NH₄. One of the samples has a significant number of defects on the Fe sites and is called the defect jarosite; others are referred to as A-jarosite. The samples, their compositions, and the entropies at T = 298.15 K are:

Sample	Chemical composition	S o/(J mol−1 K−1)
K-jarosite	K0.92(H3O)0.08Fe2.97(SO4)2(OH)5.90(H2O)0.10	427.4 ± 0.7
Na-jarosite	Na0.95(H3O)0.05Fe3.00(SO4)2(OH)6.00	436.4 ± 4.4
Rb-jarosite	RbFe2.98(SO4)2(OH)5.95(H2O)0.05	411.9 ± 4.1
NH4-jarosite	(NH4)0.87(H3O)0.13Fe3.00(SO4)2(OH)6.00	447.2 ± 4.5
Defect jarosite	K0.94(H3O)0.06Fe2.34(SO4)2(OH)4.01(H2O)1.99	412.7 ± 4.1

There are additional configurational entropies of 13.14 and 8.23 J mol⁻¹ K⁻¹ in defect and NH₄-jarosite, respectively. A detailed analysis of the synchrotron X-ray diffraction patterns showed a large anisotropic peak broadening for defect and NH₄-jarosite. The fits to the low-temperature (approx. <12 K) C _p data showed that our samples can be divided into two groups. The first group is populated by the K-, Na-, Rb-, and NH₄-jarosite samples, antiferromagnetic at low temperatures. The second group contains the H₃O-jarosite (studied previously) and the defect jarosite. H₃O- and defect jarosite are spin glasses and their low-T C _p was fit with the expression C _p = γT + ΣB _j T _j , where j = (3, 5, 7, 9). The linear term is typical for spin glasses and the sum represents the lattice contribution to C _p. Surprisingly, the C _p of the K-, Na-, Rb-, and NH₄-jarosite samples, which are usually considered to be antiferromagnetic at low temperatures, also contains a large linear term. This finding suggests that even these phases do not order completely, but have a partial spin-glass character below their Néel transition temperature.  相似文献   

The Fall of the Košice Meteorite          下载免费PDF全文

Pavel P. Povinec  Juraj Tóth 《Meteoritics & planetary science》2015,50(5):851-852

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First lightcurve observations and rotation of minor planet 127 Johanna     

Imre Toth 《Planetary and Space Science》1997,45(12):1625-1637

Photoelectric observations of the minor planet 127 Johanna were made in the UBV (RI)_c photometric system during its apparition in 1991 at the Piszkéstetõ mountain-station of Konkoly Observatory from August to December, when it showed a brightness variation with an amplitude of about 0.2 magnitude. The derived H, G values in the two-parameter magnitude system in V are 8.459 ± 0.013 and 0.114 ± 0.020, respectively. The determined V linear phase coefficient is of 0.036 ± 0.001 (mag/deg). The value of G and the observed values of color indices (U-B), (B-V) confirm that this asteroid belongs to the C taxonomic class as it was previously classified. The estimated effective diameter is between 96 and 118 km if the assumed V geometric albedo is of 0.06 and 0.04, respectively. The available data suggest a pure principal axis rotation mode. The mean synodic rotational period of the asteroid 127 Johanna is 6.94 ± 0.29 h. The uncertainty is due to the changing of aspect geometry. This value of the synodic rotation period means that this asteroid has an intermediate rotation period. The sense of rotation is prograde as indicated by the temporal evolution of the time derivative of the ecliptic longitude of the phase angle bisector as well as with the increasing synodic period of rotation during the same interval (October/November and December in 1991). The composite lightcurves created for short arc time data reveal structures with breakings and linear portions in V; this fact and the Fourier coefficients indicate a probably irregularly shaped body. There are slight indications that the B-V is redder close to the brightness minimum and the V-R_c is redder at the brightness maximum, and the periodic behavior cannot be proved in V-I_c. The less full rotational phase coverage of the observational data is insufficient to construct a shape model. The accurate pole orientation obviously cannot be determined using one opposition lightcurve data only. Further observations are required to get a more accurate knowledge of the physical parameters of this asteroid. For this purpose, a good opportunity to perform observations arose in December 1996, when this asteroid was in opposition at the northernmost declination.  相似文献   

Abrupt climate change near the poles     

Klaus Keller  Richard S. J. Tol  Ferenc L. Toth  Gary W. Yohe 《Climatic change》2008,90(1-2):1-4

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