Results of the earth-tide measurements at the Pecný station (CSSR)     

Zdeněk Šimon  Stanislav Holub  Reviewer J. Pícha 《Studia Geophysica et Geodaetica》1980,24(1):12-16

¶rt;mam mam a¶rt;u, m u a nuu mauu nu¶rt; 1970–1977. nauaumGs 11 No 131, 201 uGs 15 No 228. a¶rt; ¶rt;uam mauau ¶rt;u um. ¶rt;uu au naam nuu nu¶rt; ma. 2,uuu au ma. 3.

---

---

Paper presented at the IUGG XVII Plenary Meeting, Canberra, Dec. 1979.  相似文献   

On the character of the connection between geomagnetic activity and chromospheric flares     

Jaroslav Halenka 《Studia Geophysica et Geodaetica》1964,8(3):255-267

  相似文献   

Isotopic age and metamorphic history of the banded gneiss at Danmarkshavn,East Greenland     

Rudolf H. Steiger  Gorica Harnik-Šoptrajanova  Emil Zimmermann  Niels Henriksen 《Contributions to Mineralogy and Petrology》1976,57(1):1-24

Along the northern part of the East Greenland coast the Caledonian structures are superimposed on an older fold system called the Carolinidian. Traces of this Carolinidian belt are preserved in a few isolated fragments within the Caledonian fold belt. According to Haller (1970) one of these fragments exhibiting the typical Carolinidian NNW to NW-trending infrastructural folds is the peninsula of Germania Land which is accessible near the Danish weather station Danmarkshavn. The rock sampled there is a banded gneiss of granodioritic composition with steeply inclined, NNW-trending layers. Isotopic age determinations yielded essentially two groups of ages: 1) 3,000±150 m.y. (zircon suite and Rb/Sr whole rock analyses of layers) and 2) 320–380 m.y. (Rb/Sr mineral isochrons, U-Th-Pb on sphene, K/Ar on hornblende and biotite). The egg-shaped zircons support a sedimentary origin of the banded gneiss and in conjunction with the Rb/Sr whole rock ages determine the age of formation of the banded gneiss (or its last high grade metamorphism) some 3,000 m.y. ago. No other Precambrian metamorphism or orogeny is recorded in the rock. The ages between 320–380 m.y. date a thermal event of lower amphibolite facies grade related to a late Caledonian spasm.The new isotopic data reveal the existence of very old rocks in the hinterland — away from the direction of thrusting—of the East Greenland Caledonian belt. With respect to the age of the Carolinidian fold system three geological interpretations are compatible with the results of this study:

1.	the Carolinidian fold system formed approximately 3,000 m.y. ago;
2.	the banded gneiss represents part of an old basement: the Carolinidian orogeny is younger than 3,000 m.y. Its marked structural imprint on the Danmarkshavn area was accompanied by very low grade metamorphism not recognised in the isotopic record;
3.	the fold structures observed in the Danmarkshavn area are not of Carolinidian age but belong to an earlier fold system preserved in the basement.

  相似文献   

Uranium in spinel peridotite inclusions in basalts from Sardinia   总被引：2，自引：0，他引：2  

Jaroslav Dostal  Silvio Capedri 《Contributions to Mineralogy and Petrology》1976,54(4):245-254

The uranium distribution in spinel peridotite inclusions and their host basalt from Sardinia, Italy, was determined by fission-track mapping. Whole-rock U concentrations range from 14 to 55 ppb. Although the partitioning of U among major silicate phases of the inclusions — olivine, orthopyroxene and clinopyroxene — remains roughly constant, the U content in the minerals is highly variable, e.g. ranging from 27 ppb to 177 ppb in clinopyroxene. The U variation in the minerals shows no apparent correlation with their major element chemistry. Liquid which equilibrated with the assemblages of inclusions with high U content, had U concentrations higher than those found in basaltic rocks. It is suggested that the inclusions were contaminated with a phase strongly enriched in U and subsequently recrystallized. The available data show that spinel peridotite inclusions of basaltic rocks frequently have complex multistage evolution and thus cannot provide a representative picture of the upper mantle radioactivity.  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   

On some properties of Venedikov's method of tidal analysis     

Bernard Ducarme  Reviewer J. Pícha  Reviewer Z. Šimon 《Studia Geophysica et Geodaetica》1976,20(3):301-303

  相似文献   

Images of post-flare coronal structures in X-rays   总被引：1，自引：0，他引：1  

Zdeněk Švestka  Paul Hick 《Solar physics》1986,104(1):187-190

This is an extended abstract of several papers mentioned in the references describing extensive coronal structures related to radio continua and imaged in > 3.5 keV X-rays.Proceedings of the Workshop on Radio Continua during Solar Flares, held at Duino (Trieste), Italy, 27–31 May, 1985.  相似文献   

Evolution of the optical and hard X-ray activity of AM Her in a season dominated by the high states     

Vojtěch Šimon 《Astrophysics and Space Science》2016,361(7):235

  相似文献   

Some remarks on the estimation of geothermal topocorrections     

Jan Šafanda  Reviewer C. Matyska 《Studia Geophysica et Geodaetica》1987,31(3):284-300

Summary The paper deals with some problems connected with the evaluation of the temperature gradient topocorrections for the purposes of the Earth's heat flow measurements. Some errors, occurring in the routine use of the method, suggested by Jeffreys and Bullard (JB method), are discussed. An example of simple topographic features is used to compare this method with the results obtained by a numerical solution of the heat conduction equation (NS method) by means of the finite difference method. The calculations have shown that the NS method is more precise, but its results are very sensitive to the approximation of the surface used. A stepwise approximation of the surface used in a 3-D model of a real mountainous region causes artificial oscillations of the surface values of the topocorrections, and the accuracy of the obtained results is comparable with that of the JB method. Thus, we are faced with the problem of a more appropriate approximation of the relief without the mentioned negative consequences to the superficial values of the topocorrections.

---

¶rt;am n, a mnauu ua¶rt;uma mnam nu uu mn nma. u m uu, nu n mu nuu m¶rt;a, m n¶rt; u u a¶rt; (J B m¶rt;). a nu nm mnau mm m¶rt; a u u au mnn¶rt;mu (NS m¶rt;) n n am. uu naau, m NS m¶rt; m JB m¶rt;, m mam u mum annuauu nmu. B a - ¶rt;u ¶rt;mum amu nu¶rt;um mnama annuau u au nm au mnu u mm n mam aua mm JB m¶rt;a. a naa, m n unau num NS m¶rt;a a¶rt; nmu a¶rt; nuuu nmu.

  相似文献   

Lead isotope and trace element composition of K-feldspars from peraluminous granitoids of the Late Devonian South Mountain Batholith (Nova Scotia, Canada): implications for petrogenesis and tectonic reconstruction     

Jaroslav Dostal  A. K. Chatterjee 《Contributions to Mineralogy and Petrology》2010,159(4):563-578

The South Mountain Batholith (SMB) of southwestern Nova Scotia (Canada) is a Late Devonian (~375 Ma) composite intrusion, which crops over an area of about 7,300 km². This peraluminous granitoid body consists of rocks ranging from granodiorite through monzogranite and leucomonzogranite to leucogranite that locally host greisen tin-base metal mineralization. K-feldspar displays large compositional variations of trace elements and Pb isotopic ratios, particularly in the highly fractionated rocks. Many variations are consistent with processes of fractional crystallization, but a distinct enrichment of Rb, Li and Cs accompanied by low K/Rb, Ba/Rb, Eu/Eu* and K/Cs ratios point to the role of fluids during the late stages of magmatic evolution. The correlation of Pb isotopic ratios with the enriched elements and their ratios implies that the isotopic variations are an integral part of the evolution of the SMB. Together with well-defined isochronal relationships of Pb systems in the feldspars, the correlation suggests that fractional crystallization accompanied in the late stages by fluid fractionation led to the formation of Li–F-rich leucogranites. Internally derived U-rich fluids fractionated U/Pb ratios, which in turn produced distinct variations of ²⁰⁶Pb/²⁰⁴Pb and ²³⁸U/²⁰⁴Pb ratios in K-feldspars. This implies that the Pb isotopic values of K-feldspar, which have traditionally been used for tectonic reconstructions, might have been modified in many granitic rocks. Thus, only early magmatic K-feldspars, which show no discernible effects of fluid fractionation yield the initial Pb isotopic compositions of the parental granitic magmas and their sources. The data also show that the geochemical characteristics of the leucogranites are the results of magmatic evolution rather than a distinctive source.  相似文献