Martinec Z 1993: Effect of lateral density variations of topographical masses in view of improving geoid model accuracy over Canada. Contract report for Geodetic Survey of Canada, Ottawa, Canada
A detailed petrographic and mineral-chemical study on metapelites from the Meliatic accretionary wedge complex (Bôrka Nappe, Western Carpathians, Slovak Republic) reveals the HP character of the samples using quantitative phase diagrams contoured with mineral composition, H2O mode isopleths and garnet-phengite thermometry. The presented PT pseudosections prove that small-scale differences in bulk rock composition are responsible for the variations in the mineral assemblages formed at the same PT conditions. The peak conditions indicate blueschist facies metamorphism (520–620 °C, 11–14 kbar) and are correlated with the 150–165 Ma subduction of the Mesozoic Meliata Oceanic branch of the Neotethys. Continuous decrease of P and T from peak conditions enabled the metapelitic rocks to preserve their HP assemblages. The presented HP conditions and retrograde PT path with decreasing P and T are characteristic of subduction zone tectonic settings which are in agreement with most of the geodynamic and tectonic reconstructions for the area.
Authors:P. Varga, Z. Bus, B. Süle, A. Schreider, C. Bizouard, D. Gambis, and C. Denis
In its first part this work focuses on connection of length of day (LOD) with centered and eccentric geomagnetic dipole fields described with the use of Gaussian coefficients derived from global geomagnetic observations is discussed for the epoch 1900–2000. The statistical comparison of temporal variation of earth magnetic and astronomical data shows close correlation of geomagnetic dipole momentum
and ΔLOD. It should be mentioned that the time-correlation is closer when the centred geomagnetic dipole is used for statistical modelling. In the same time no relation was found between ΔLOD and the orientation variations of the geomagnetic dipole.In the second part of present study the connection of geomagnetic field and the LOD is investigated in geological time-scale. A significant ΔLOD was found which coincides in time with the geomagnetic Mesozoic low. The reason of this coincidence is enigmatic.
Authors:Petya Kovacheva, Boyan Todorov, and Rumyana Djingova
This paper deals with the influence of sharp temperature variations on the geochemical fractionation and bioavailability of 241Am, 60Co and 137Cs in Fluvisol soil. The study was performed using soil contaminated with aqueous solutions of 241Am, 60Co and 137Cs in the laboratory and stored for three years at temperatures within the range of 10–18 ºC and soil moisture from 20 to 30 wt %. Afterward the soil was divided into three equal parts and conditioned for one month at 10–18 ºC, −18 ºC and 40 ºC temperature regimes, respectively. The impact of the storage conditions on geochemical forms of the radionuclides was investigated using single extraction of exchangeable 137Cs with 1 M NH4NO3 and sequential extraction of 241Am and 60Co, and by gamma-spectrometric measurement. The influence of temperature rise up to 40 ºC over a period of one month on the transfer factors (TFs) of the radionuclides from the investigated soil to orchard grass (Dactylis glomerata L.) was evaluated. The results showed that deep freezing and a sharp temperature increase continuing for one month led to re-distribution of 241Amand 60Co between the soil phases and provoked an increase of the exchangeable 137Cs. Freezing led to a decrease of 241Am in the residual fraction and an increase of oxide-bound americium. The storage at frozen conditions led to decrease of oxide bounded 60Co and increased immobilization in the residual fraction. Conditioning at high temperature increased the migration ability of 241Amand 137Cs, while immobilization of 60Co was registered. Conditioning at a sharp temperature increase before the growing season led to higher values of the TFs of all the studied radionuclides. This effect was highest for 137Cs. The sharp temperature change of contaminated Fluvisol soil lasting one month was found to create a risk of increased migration and bioaccumulation of radionuclides.
We have obtained empirical laws for the variation of the Earth parameters with geologic time that are in agreement with coral fossil data obtained by Wells and Runcorn. Our model predicts that the day is lengthening at a rate of 2 ms/century at the present time. The length of the day when the Earth was formed is found to be 6 hours and the synodic month 56 days. The angular momentum of the Earth-Moon system is found to be increasing with time. The origin of the presently observed acceleration of the Moon is explained. The model predicts that the Moon is accelerating at 20.6 arc sec/cy2 at the present time.
Authors:József Fekete, Csanád Sajgó, István Horváth, Zoltán Kárpáti, István Vetõ, and Magdolna Hetényi
The geochemical facies of Hungarian thermal waters were the object of this study. Samples were separated into groups by relative ages (δ18O values). Mature and immature subgroups were formed on the basis of dissolved (semi)volatile organic compounds. The oldest (connate) waters form one group with a small number of samples. The subgroups containing different small molecular-sized soluble aromatics differ sharply in their chemical features (sodium, hydrogen carbonate, iodine, ammonium etc. content). The origin of the organic matter may differ in the subgroups as inferred by their different δ18O values and ten times greater halogen contents.
Our results show that the decomposition of organic matter produces small molecular-sized aromatic compounds and also influences the amounts of inorganic components in thermal waters, through the increase of feldspar hydrolysis and carbonate dissolution.
Authors:Anita Erőss, Ferenc Zsemle, and Eszter Pulay
2014 : A Boltív-forrás vízhozamának és fizikai, kémiai paramétereinek változása a csapadékesemények és a Duna vízállás függvényében. Értékelés archív adatok és recens mérések alapján (Temporal variation of the discharge and physico-chemical parameters
The spatio-temporal patterns of the seismicity are shown. The earthquake occurrence is connected to the strain rate on the basis of Kostrov (1974) equation. It is shown that in the Pannonian Basin the seismic rates are 10-7-10-6. This values were derived from the local earthquake catalogues of the area of Komárom, Dunaharaszti (near Budapest) and Kecskemét. It is shown that the earthquake occurrence in Hungary has a well expressed diurnal periodicity. Similar phenomenon was detected in the case of earthquakes of all Europe and in Turkey in case of weak (ML = 3.0) seismic events.