Geochemical exploration of a Precambrian Batholith, source of a Cu-W mineralization of the tourmaline breccia in Southern Finland     

Gabor Gal  Kai Front  Kristiina Aro 《Journal of Geochemical Exploration》1981,15(1-3)

The Hämeenkyrö batholith is a round-shaped plutonic body of an areal size of 147 km². It is composed of calc-alkaline to alkaline rocks that intruded previously metamorphosed Svecofennian volcanogenic and sedimentary schists 1860 Ma ago. The Cu-W bearing tourmaline breccia of the Ylörvi deposit occurs in metavolcanic rocks close to the eastern contact of the batholith.The average sampling density in the batholith was 1 sample per km², and 175 samples were analyzed for Cu, Au, Ag, Ni, Pb, Co, Zn, S by AAS for SiO₂, TiO₂, Al₂O₃, FeO, MnO, MgO, CaO, Na₂O, K₂O, As, Sn and P by X-ray fluorescence. Mo and W were determined colorimetrically. Barth mesonorms were calculated for each sample and the rock type was determined according to Streckeisen's classification. Element distributions are displayed on contour maps.The rock types of the batholith exhibit an asymmetric concentric arrangement, the order from the center towards the margin being alkali-feldspar granite, syenogranite, monzogranite, quartz monzonite, quartz syenite, alkali-feldspar, quartz syenite, syenite and alkali-feldspar syenite. Anomalously high Cu, As, Sn, S, K₂O and Na₂O contents have been found at the eastern margin of the batholith in a N—S-trending zone, which is characterized by hydrothermal alteration phenomena, propylitization, tourmalinization and scapolitization. Three anomalous areas have been defined within this zone, one of them is associated with the Ylöjärvi deposit and the other two are regarded as exploration targets.  相似文献   

The effect of the irregularities of the shape of the Earth's core-mantle boundary on the observed acceleration of gravity     

Jiří Trešl  Reviewer M. Pick 《Studia Geophysica et Geodaetica》1981,25(1):5-13

Summary The disturbing gravitational effect of the irregularities of the shape of the coremantle boundary are studied at a point on the Earth's surface. The effect is computed for models of local and zonal distribution of the disturbing masses under the assumption that the total mass of the Earth remains constant. Formulae giving the disturbing gravitational effect as a function of the distribution of the disturbing masses and of the position of the point of observation on the Earth's surface are derived for the individual models. Numerical values of the disturbances have been calculate in all cases.  相似文献   

Determination of polar motion by Doppler tracking of artificial satellite     

D. Gambis  F. Nouël 《Journal of Geodesy》1980,54(1):103-118

Doppler tracking of artificial satellites has been applied to determine the pole components through an experiment called MEDOC. In addition to developing scientific aspects dealing with polar motion, it is proposed to promote new observational techniques and to investigate the possibility of operating an international permanent service. So far, nearly two years of bi-daily solutions have been derived. Each improvement of computational procedures, data processing and station component determination has contributed to better precision in the computed pole positions. MEDOC pole coordinate solutions show good agreement with DMA and BIH global solutions corrected for annual terms. Differences of the smoothed values are less than one meter for both components. The MEDOC experiment was initiated by the GRGS (Groupe de Recherches de Géodésie Spatiale) and took place in 1977 and 1978. The experiment as presently organized will continue up to 1980. Future improvements are still foreseen by increasing the number of observing sites and refinement of the force models, but already international involvement is taking place in the MEDOC experiment.  相似文献   

An effective method of frequency analyses of time series of geo-physical quantities     

František Pechala  Nina Věková  Reviewer J. Anděl 《Studia Geophysica et Geodaetica》1980,24(3):302-313

a u uma naau ¶rt; m¶rt; ¶rt; aaua ¶rt;auu uu. naau ¶rt; naam , ¶rt;mu mau a, m aa naau ¶rt;am n a au aauu uu auumu m amu m aaa um ¶rt;uam. m¶rt; m ¶rt;mam mu ¶rt;a nu auu u m mu, ma m nuu ma a a .  相似文献   

Dynamic properties of the probe for measuring the temperature gradient     

Milan Krešl  Reviewer J. Vitovec 《Studia Geophysica et Geodaetica》1976,20(2):186-192

Summary The paper analyses the behaviour of a probe for direct measurements of temperature increase with depth in boreholes and derives transient characteristics of a gradient probe using the electrothermal analogy.  相似文献   

Magnetohydrodynamic oscillations due to precessional motion     

Jiří Trešl  Reviewer G. Siráň 《Studia Geophysica et Geodaetica》1977,21(1):27-34

Summary The motion of a non-viscous liquid medium with an ideal electrical conductivity, enclosed in the ellipsoidal cavity of an envelope subject to precessional motion, is investigated. Inside the cavity there is a toroidal magnetic field. It is proved that the precessional motion of the envelope generates forced oscillations of the medium with a period of 24 hours and two different types of eigen oscillations. Expressions for computing the amplitudes and frequencies of all types of oscillations are derived. The maximum values of disturbance fields are determined for geophysically acceptable parameters.  相似文献   

Determination of the ⁸⁷Rb decay constant     

D.W. Davis  J. Gray  G.l. Gumming  H. Baadsgaard 《Geochimica et cosmochimica acta》1977,41(12):1745-1749

The decay constant ⁸⁷Rb has been redetermined by measuring the amount of radiogenic ⁸⁷Sr produced over a period of 19 years, in 20 g samples of purified RbClO₄, using isotope dilution techniques. The rubidium sample was spiked with ⁸⁴Sr and the nanogram quantities of strontium separated by coprecipitation with Ba(NO₃)₂. Analyses were carried out on a 25cm, 90° sector mass spectrometer equipped with a Spiraltron electron multiplier. Measurement of three independent ratios permitted continuous monitoring of the ion beam fractionation. The average of nine determinations gives a value for the decay constant of $\text{1.419(±0.012) × 10}{}^{\mathrm{?11}}\text{yr}{}^{\mathrm{?1}}\text{(2σ)}$. [$\text{τ}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 4.89(±0.04) × 10}{}^{10}\text{yr}$.]  相似文献   

Tveitite,a new calcium yttrium fluoride     

Sveinung Bergstøl  Brenda B. Jensen  Henrich Neumann 《Lithos》1977,10(1):81-87

Tveitite is a new mineral with formula of the type $\text{Ca}{}_{\mathrm{1?x}}\text{(}\text{Y, RE}\text{)}{}_{\mathrm{x}}\text{F}{}_{\mathrm{2+x}}\text{where}\text{x}$ is approximately 0.3. It is found in a cleavelandite pegmatite at Høydalen in Tørdal, Telemark, S. Norway. The sub-cell is thought to be monoclinic, $\text{a}\text{′=3.924,}\text{b}\text{′=3.893,}\text{c}\text{′=5.525, ß=90°26′,}\text{Z}\text{=2}$. The structure is very similar to that of fluorite and can be described in terms of a pseudo-cubic cell $\text{[1}\text{1}\text{0]}{}_0\text{= 5.527, [110]}{}_0\text{= 5.527,}\text{c}\text{= 5.525, α = 90°18′, γ = 89°37′}$ which contains approximately 1[YCa₃F₉]. The mineral shows twinning in at lest three different directions giving a grating structure probably due to high-low inversion. DTA studies show an inversion point at about 670°C. Material heated above this temperature gives X-ray diffraction patterns corresponding to yttrofluorite (a₀ 5.528). The effect of trivalent ions on the stability of fluorite is discussed.  相似文献   

Industrial minerals and rocks, aggregates and natural stones in the Nordic countries     

Kurt Johansson Rune B. Larsen Markku J. Lehtinen Lars Persson Mika Raeisaenen Stig A. Schack Pedersen Paer Weihed Nils-Gunnar Wik 《《幕》》2008,31(1):133-139

The Nordic countries, including Greenland, have a long tradition in mining. The industrial minerals sector is expanding in most Nordic countries and extensive development has taken place during the last few years. The main commodities mined are carbonate rocks, quartz, feldspar, apatite, olivine and talc.
A number of diferent types of dimension stones are quarried in all countries. Rock aggregates are increasingly important, replacing sand and gravel aggregate as construction materials in some countries due to the need to protect ground water supplies.  相似文献   

Biological structures as a source of habitat heterogeneity and biodiversity on the deep ocean margins   总被引：1，自引：0，他引：1  

Lene Buhl-Mortensen  Ann Vanreusel  rew J. Gooday  Lisa A. Levin  Imants G. Priede  Pål Buhl-Mortensen  Hendrik Gheerardyn  Nicola J. King  & Maarten Raes 《Marine Ecology》2010,31(1):21-50

Biological structures exert a major influence on species diversity at both local and regional scales on deep continental margins. Some organisms use other species as substrates for attachment, shelter, feeding or parasitism, but there may also be mutual benefits from the association. Here, we highlight the structural attributes and biotic effects of the habitats that corals, sea pens, sponges and xenophyophores offer other organisms. The environmental setting of the biological structures influences their species composition. The importance of benthic species as substrates seems to increase with depth as the complexity of the surrounding geological substrate and food supply decline. There are marked differences in the degree of mutualistic relationships between habitat-forming taxa. This is especially evident for scleractinian corals, which have high numbers of facultative associates (commensals) and few obligate associates (mutualists), and gorgonians, with their few commensals and many obligate associates. Size, flexibility and architectural complexity of the habitat-forming organism are positively related to species diversity for both sessile and mobile species. This is mainly evident for commensal species sharing a facultative relationship with their host. Habitat complexity is enhanced by the architecture of biological structures, as well as by biological interactions. Colony morphology has a great influence on feeding efficiency for suspension feeders. Suspension feeding, habitat-forming organisms modify the environment to optimize their food uptake. This environmental advantage is also passed on to associated filter-feeding species. These effects are poorly understood but represent key points for understanding ecosystems and biodiversity on continental margins. In this paper we explore the contributions of organisms and the biotic structures they create (rather than physical modifications) to habitat heterogeneity and diversity on the deep continental margins.  相似文献