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11.
Miroslav Štemprok 《Mineralium Deposita》1967,2(2):102-118
Zusammenfassung Die Zinnvererzungen im Erzgebirge stehen in engen räumlichen Beziehungen zu den Granitkontakten. Dieses Merkmal wird durch eine strukturelle Rolle der konsolidierten Endokontaktpartien der Granite beim Aufstieg der Erzlösungen erklärt. Die Mineralisationslösungen stammen aus den tieferen Teilen der Erdkruste; die Lagerstätten stehenin einer paragenetischen Stellung zu den Graniten. Die Zinn-Wolfram Mineralisation verlief in mehreren Mineralisationsstadien. In den Quarzgängen konnte eine deutliche innere Gangmetasomatose beobachtet werden, bei der ine ältere Quarzgangfüllung verdrängt wurde. Die symmetrischen Salbänder mancher Mineralien um die Quarzgänge sind durch Verdrängung des Quarzes vom Gangkontakt aus gebildet worden. Die Abschnitte der Quarzgänge mit Feldspäten die den Pegmatiten sehr ähnlich sehen, sind durch Metasomatose nach der Greisenbildung entstanden. Die Granitbildung wurde von extensiven Nebengesteinsumwandlungen begleitet bei der Kalifeldspatbildung (I–II), Albitisierung, Vergreisung, Serizitisierung, Kaolinitisierung, und Hämatitisierung unterschieden werden. Die wichtigsten geologischen und mineralogischen Merkmale der Lagerstätten sind in Tabellen zusammengefaßt.
The tin-tungsten mineralization in the Kruné hory Mts. /Erzgebirge shows a close spatial association with the granite contacts. This feature is explained by the structural control of solid endocontact part of the granite bodies for the import of postmagmatic solutions. The mineralizing solutions were derived from the deeper parts of the earth's crust, the ore deposits being thus in a paragenetic position to the granites. The tin-tungsten mineralization occurred during an interrupted process of metallization in the course of several stages. In the quartz veins a distinct intravenous metasomatism was observed with the replacement of earlier quartz vein fillings. The symmetrical selvages of some minerals around quartz veins originated by the replacement of quartz from the wall contact. The sections of the quartz veins with felspars resembling very closely the pegmatites were formed by the post-greisen metasomatism of the quartz veins. The emplacement of granites was accompanied by extensive wall- rock alterations of which potash- felspatization (I and II), albitization, greisenization, sericitization, kaolinization and hematitization were distinguished. The main geological and mineralogical features of the deposits are summarized in tables.相似文献
12.
13.
Vladimír Kropáček Miroslav Krs Reviewer V. Bucha 《Studia Geophysica et Geodaetica》1975,19(3):261-274
Summary The paper is devoted to the study of the magnetic properties, of the volume magnetic susceptibility in a weak magnetic field, of the specific magnetic susceptibility in a strong magnetic field, of natural remanent magnetization and its stability in A.C. fields, and of the temperature dependence of magnetic susceptibility of natural Mn-oxides. Samples of pyrolusite, polianite, manganite, hausmannite, psilomelan and wad from different localities all over the world were studied; the measured values are statistically treated so that the given values are valid in general. Hausmannite displayed typical values of the magnetic susceptibility, different from the values of the other Mn-oxides. In general, many natural Mn-oxides contain heterogeneous admixtures of Fe-oxides, which are responsible for their ferromagnetic properties. A high degree of magnetic hardness, predetermining the minerals for palaeomagnetic research, was proved with many of the natural Mn-oxides. 相似文献
14.
Summary The paper discusses geophysical phenomena observed over tholeiitic dykes detected in the Eastern Desert of Egypt (Nubian Block). The dykes show specific physical properties and are either normally or reversely polarized along their whole length over 120 km. Dykes of similar properties may also be interpreted from airborne geophysical maps in Saudi Arabia (Arabian Block). Magnetic fields of the tholeiitic dykes were interpreted quantitatively: they fit the magnetic pattern over the Red Sea. The study emphasizes those geophysical phenomena which may serve as criteria for recognition of regions with rift tectonics development. 相似文献
15.
Işık Yilmaz Marian Marschalko David Lamich Marián Drusa Jiří Machačík Silvie Heviánková Miroslav Kyncl Eva Lacková Iva Bestová David Krčmář Egon Stutz Martin Bednárik 《Environmental Earth Sciences》2014,72(8):2947-2955
In engineering geology a number of factors affecting foundation conditions are taken into consideration during engineering-geological investigations. This article deals with the factor of heat sourced from a structure (brick kiln) as a restrictive factor in foundation engineering in clay soils and introduces a documentation of soil deformation observations as an impact of the heat transmission into the geological environment. It was carried out in Southern Moravia in the Czech Republic, where the dominant foundation soils are Neogeneous clays where differential settlements of a tunnel kiln structure occurred as a result of ignoring the boundary conditions of temperature changes in the soil environment. The brick kilns caused heterogeneous spatial changes in the subsoil temperatures. This consequently resulted in differential settlements due to temperature changes originating from the kilns. The differential settlements reached as much as 150 mm. The major objective of the article is to highlight the importance of the heat transmission from buildings into the geological environment as a factor which should be considered in engineering geology and its application in planning. A new procedure for reducing or elimination of ground movements sourced from underlying clayey soils depending on the heat changes was also suggested in this context. 相似文献
16.
From the assumption of symmetry of ratio of Fermion masses and masses of bosons ratio results the hypothetical mass of quark-lepton bosonm
wes and hypothetical mass of electron neutrinom
ve. 相似文献
17.
From the observed present parameters of the Universe and the model properties of an expansive non-decelerative universe it results that the value of Boltzmann's constant (coefficient)k does not change only before the end of radiation era, but also in the matter era; with the increase of gauge factora, it decreases as (a
–1)1/4. 相似文献
18.
Timothy J. Galvin Miroslav D. Filipović Evan J. Crawford Graeme Wong Jeff L. Payne Ain De Horta Graeme L. White Nick Tothill Danica Drašković Thomas G. Pannuti Caleb K. Grimes Benjamin J. Cahall William C. Millar Seppo Laine 《Astrophysics and Space Science》2012,340(1):133-142
A series of new radio-continuum (λ=20 cm) mosaic images focused on the NGC?300 galactic system were produced using archived observational data from the VLA and/or ATCA. These new images are both very sensitive (rms?=60 μJy) and feature high angular resolution (<10?″). The most prominent new feature is the galaxy’s extended radio-continuum emission, which does not match its optical appearance. Using these newly created images a number of previously unidentified discrete sources have been discovered. Furthermore, we demonstrate that a joint deconvolution approach to imaging this complete data-set is inferior when compared to an immerge approach. 相似文献
19.
The reaction of CN? with cyanoacetylene (HC3N), has been studied as a function of the HC3N pressure in a quadrupole tandem mass spectrometer. The mass spectra revealed the fast depletion of the CN? parent ion and formation of larger anions of rapidly growing size. Most of the ions observed were found to belong to two series of products: (HC3N)x·C2p+1N? and (HC3N)x·C2pN? resulting from the sequential additions of HC3N molecules and loss of HCN or HCCN molecules. The mechanism and energetics of the first two reaction steps are briefly discussed. The laboratory data are compared with those from the Cassini CAPS-ELS spectrometer. It is believed that the reactions observed could account for the growth of anions in Titan’s ionosphere. 相似文献
20.
Filip Oulehle Milan Fischer Jakub Hruška Tomáš Chuman Pavel Krám Tomáš Navrátil Miroslav Tesař Miroslav Trnka 《水文研究》2021,35(5):e14204
In 1994, a network of small catchments (GEOMON) was established in the Czech Republic to determine input–output element fluxes in semi-natural forest ecosystems recovering from anthropogenic acidification. The network consists from 16 catchments and the primary observations of elements fluxes were complemented by monitoring of biomass stock, element pools in soil and vegetation, and the main water balance components. Over last three decades, reductions of SO2, NOx and NH3 emissions were followed by sulphur (S) and nitrogen (N) deposition reductions of 75% and 30%, respectively. Steeper declines of strong acid anion concentrations compared to cations (Ca, Mg, Na, K, NH4) in precipitation resulted in precipitation pH increase from 4.5 to 5.2 in bulk precipitation and from 4.0 to 5.1 in spruce throughfall. Stream chemistry responded to changes in deposition: S leaching declined. However at majority of catchments soils acted as a net source of S to runoff, delaying recovery. Stream pH increased at acidic streams (pH < 6) and aluminium concentration decreased. Stream nitrate (NO3) concentration declined by 60%, considerably more than N deposition. Stream NO3 concentration was tightly positively related to stream total dissolved nitrogen to total phosphorus (P) ratio, suggesting the role of P availability on N retention. Trends in dissolved organic carbon fluxes responded to both acidification recovery and to runoff temporal variation. An exceptional drought occurred between 2014 and 2019. Over this recent period, streamflow decreased by ≈ 40% on average compared to 1990s, due to the increases of soil evaporation and vegetation transpiration by ≈ 30% and declines in precipitation by ≈ 15% on average across the elevational gradient. Sharp decreases of stream runoff at catchments <650 m a.s.l. corresponded to areas of recent forest decline caused by bark beetle infestation on drought stressed spruce forests. Understanding of the interactions among legacies of acidification and eutrophication, drought effects on the water cycle and forest disturbance dynamics is requisite for effective management of forested ecosystems under anthropogenic influence. 相似文献