A new solar observing station     

Jaroslav Halenka 《Studia Geophysica et Geodaetica》1959,3(3):294-295

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Josef petřík (1866–1966)     

Josef Ryšavý Jaroslav Pudr 《Studia Geophysica et Geodaetica》1966,10(4):486-486

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Computation of spectra of some simple functions using various types of Windows     

Jaroslav Střeštík  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1982,26(2):145-159

Summary In the introductory part of the paper, a method of computing spectra by computer is described, which cuts down the computer time required without using the Fast Fourier Transformation. Windows which can be used to adjust the resultant spectrum are described. The spectra of a constant, a linear function, a sine function, of the superposition of two sine functions and of the superposition of a sine function with a constant and linear function are described in detail and it is demonstrated how these spectra change when different types of windows are used. The suitability of the separate windows for various purposes is discussed. Finally, in the case of the superposition of two sine oscillations it is shown under what conditions the two frequency components can be distinguished.  相似文献   

Inception and demise of a Neoproterozoic ocean basin: evidence from the Ougda complex,western Hoggar (Algeria)     

J. Dostal  R. Caby  C. Dupuy  C. Mevel  J. V. Owen 《International Journal of Earth Sciences》1996,85(4):619-631

The Neoproterozoic Ougda magmatic complex occurs within platformal carbonate rocks in the western part of the Pan-African fold belt of the Tuareg shield (NW Africa). It is composed of - 800 Ma old, relatively high P-T (i.e., Grt + Cpx-bearing: P > 5 kbar; T≈900'Q, tholeiitic mafic/ultramafic cumulates and related rocks intruded by intermediate to mafic calcalkali plutons (e.g., Cpx+Hbl-bearing gabbro) and dikes. Apparent contrasts in structural level of crystallization indicate that the calc-alkali rocks are significantly younger than the tholeiites, which temporally correlate with a period of regional extension in this part of Africa. Intrusion of the calc-alkali rocks may have occurred during the formation of an arc after the tholeiitic rocks had been (diapirically?) emplaced within the shelf carbonates, and prior to (> 630 Ma) the Pan-African orogeny. Data reported herein indicate that the Ougda complex records the inception and demise of a Neoproterozoic ocean basin. Similar crustal sections have been described from collisional (e.g., Aleutian islands) and extensional (e.g., Ivreä-Verbano zone) settings, indicating that processes operating in both environments can generate nearly indistinguishable igneous suites; the prevalence of shallow-level calc-alkali rocks in both settings may mask the presence of more mafic, tholeiitic rocks at depth.  相似文献   

Trace element evidence for the origin of ocean island basalts: an example from the Austral Islands (French Polynesia)     

C. Dupuy  H. G. Barsczus  J. M. Liotard  J. Dostal 《Contributions to Mineralogy and Petrology》1988,98(3):293-302

The Austral Islands, a volcanic chain in the South-Central Pacific Ocean (French Polynesia) are composed mainly of alkali basalts and basanites with subordinate amounts of olivine tholeiites and strongly undersaturated rocks (phonolite foidites and phonolite tephrites). The basaltic rocks have geochemical features typical of oceanic island suites. The distribution of incompatible trace elements indicate that the lavas were derived from a heterogeneous mantle source. The chondrite-normalized patterns of the incompatible elements in basaltic rocks of the Austral Islands are complementary to those of island arc tholeiites. As supported by isotope data, the observed trace element heterogeneities of the source are probably due to mixing of the upper mantle with subducted oceanic crust from which island arc tholeiitic magma was previously extracted.  相似文献   

Relation between the field of surface heat flow and the distribution ofP n -wave velocities for continents     

Jaroslav Kubík  Reviewer A. Janáčková  Reviewer V. Červený 《Studia Geophysica et Geodaetica》1988,32(3):287-299

Summary The dependence between P_n-wave velocities and the surface heat flow, temperature at the core-mantl boundary and thickness of the Earth's crust for continents (Europe, Asia, North America and Australia) was investigated statistically in connection with the problem of lateral inhomogeneities in the upper mantle. The relations obtained were compared with those determined under laboratory conditions. The conclusion is that temperature and pressure effects may provide additional explanations of the regional variations of P_n-wave velocities observed in most continents.

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auum ¶rt;auu mu n¶rt; a nmu uua(P_n ), nm mn nm, mnam a u m mum a u¶rt;aa u n uuuma ¶rt;¶rt;m mu P_n. nua ¶rt;a mama aam u¶rt;au nu m n¶rt; amuu u u ¶rt;au u mnam a¶rt;um mmmuu mamau n¶rt;aa am. am ¶rt;, m ua uu m P_n- ¶rt; amu muma n¶rt;m auu m¶rt;uauu u a nmu muua.

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Magnitudes of detectable and localizable shocks in nw bohemia     

Vladimír Tobyáš  Jaroslav Fiedler  Dana Knaislová  Dana Procházková  Reviewer I. Pšenčík 《Studia Geophysica et Geodaetica》1985,29(1):68-74

Summary The effectiveness of recording seismic phenomena in the Kruné hory (Mts.) region in NW Bohemia by selected stations in the CSR, GDR and Poland has been estimated. Magnitude isolines of the weakest earthquakes, which can be localized and detected with an 0.9 probability, were calculated on the basis of the level of seismic disturbances at the individual stations and of the empirical dependence of the attenuation of seismic waves with distance.

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a a mum umauu uu u amu ¶rt; ana¶rt; uu uau mauu a mumuu , u a a uu n a m¶rt; mau u nuu auumu amau uu m amu u auma uuuu aum¶rt; a a mu, m mm 0.9 auuam u aum.

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On the problem of sudden commencements of geomagnetic storms as manifestations of shock waves     

Jaroslav Halenka  Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1984,28(2):164-171

nma nu SS u nmau u nau a¶rt;a ¶rt;u nma u u a au 11-mu ua. u ¶rt; nm ¶rt; n. a¶rt;am nuu nu SS u.  相似文献   

On the possibility of long-range forecasts of geomagnetic activity     

Jaroslav Halenka  Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1984,28(3):294-305

Summary The relation between geomagnetic activity and solar activity is studied in long intervals and in individual 11-year cycles, characterized by certain basic parameters, in connection with investigating the prognostic significance of long-term fluctuations of geomagnetic activity [1, 2]. A number of properties as well as sufficiently close relations with a prognostic significance have been found, such as the secular variation of geomagnetic activity, the 22-year cycle of change in the form of the behaviour of geomagnetic activity in 11-year cycles, long-term concurrence of solar and geomagnetic activity and its changes within the 11-year cycle, relations between solar and geomagnetic parameters characterizing the 11-year cycle.

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a auu uu u ¶rt; uaum amum ¶rt;u nma u u m¶rt; 11-mu ua am mu ¶rt; ¶rt;m nuauaum amumu.

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Geochemistry and petrogenesis of ophiolites from Northern Pindos (Greece)   总被引：1，自引：0，他引：1  

C. Dupuy  J. Dostal  S. Capedri  G. Venturelli 《Bulletin of Volcanology》1984,47(1):39-46

The ophiolitic complex of Northern Pindos (Greece) contains ocean-floor basalts and low-Ti mafic rocks. The former rocks are similar to recent mid-ocean ridge basalts with a light REE depletion and a La/Yb ratio < 2. The low-Ti rocks resemble boninites in their high Mg and very low Ti and Zr contents and in their REE patterns which have convex-downwards shape with a slight light REE enrichment. However, their Zr/Ti, Ti/V and Zr/Y ratios are lower than in boninites. Both rock-types could be generated by dynamic partial melting of a rising upper mantle diapir. Slight enrichment in light REE, Sr, Rb and Ba in low-Ti rocks could be the result of either metasomatic or alteration processes. Although a subduction zone origin of the sequence is possible, the geochemical data do not necessarily imply such a setting.  相似文献