[en] A geological report about ornamental granites was done in 3rd mining reservation judicial District Colonia Province Uruguay.

[en] This report is a preliminary stage of an Uruguayan granites project.

[en] Uranium behaviour in accessory spbene and products of its alteration at different stages of granitoid transformation with characteristic association of zirconium-apatite-sphene and magnetite of accessory minerals, is shown. The products of sphene alteration (due to propylitization of granatoids the sphene is replaced by leucoxene) are determined by MS-46 electron probe microanalyzer and MA-1 lazer microanalyzer. Uranium distribution in leucoxene is studied by the method of fragmentary radiography. Leucoxene pseudomorphoses at a high oxygen potential are capable of giving into solution Uranium previously sorbed by leucoxene. This fact should be taken into account when determining source of metal of hydrogenous deposits

[en] During anatexis, uranium fractionation into the melt increases with the proportion of U located outside the lattice of weakly soluble accessory minerals. Low degree of partial melting, high f_O2 and P_CO2 improve U fractionation into the silicate liquid. The study of two different samplings, free of meteoric alteration, allows to characterize the U distribution related to magmatic and late-magmatic processes. During the evolution of peraluminous magma, the proportion of U to be imputed to uraninite increases whereas the proportion to be imputed to monazite decreases. Uraninite has a clear magmatic origin and follows incompatible-element enrichment. A superimposed uraninite distribution occurs in late-magmatic shear zones and is related to the fluid oversaturation of highly evolved endogranitic intrusions. This process strongly enhances the U fertility of a granitic body. The effects of various types of alterations, currently observed in peraluminous granites, on U mobility, are briefly reviewed. Meteoric alteration strongly disturbs previous U distributions, but high U contents are generally partly preserved. Pervasive migration (low water/rock ratio) hardly proceeds in metal mobilization. Besides the nature of the fluids, the efficiency of U mobilization increases with the intensity of the spatial overlap between magmatic (and ductile) shear zones enriched in uraninite and brittle structures favouring hydrothermal circulations. 100 refs.; 16 figs.; 3 tabs

[en] In May 1984, a petite sismique estimate of the deformation modulus (E) was carried out at the Spent Fuel Test - Climax (SFT-C) at the Nevada Test site. The first part of the experiment was to repeat an earlier suite of measurements that were taken before the spent fuel was emplaced to see if any changes had resulted from heating the rock mass. The results of this measurement indicate a decrease in the modulus. However, these results are suspect in view of the findings in the second part of the experiment, which was designed to minimize the effects due to spurious resonances in the source and geophone locations. These effects were thought to bias the earlier measurements. The measurements indicate that the rock acts as a low-pass filter to the propagating wavefield. Furthermore, it is noted that the blow from a hammer is not a purely impulsive source. Therefore, depending on the type of source used and the distance away from the source, a different peak frequency and, hence, E could be measured for the same rock mass. Unless these effects are somehow factored out of a petite sismique survey, the value of E obtained could be severely biased. 20 figures

[en] A detailed description of the title pluton is presented. (P.A.)

[en] Statements of geological nature can be made on the basis of investigations of the bedrock exposed in southern Black Forest and these can, in the form of prognoses, be applied to the crystalline Basement of northern Switzerland. Such statements relate to the average proportions of the main lithological groups at the bedrock surface and the surface area of the granite body. Some of the prognoses can be compared and checked with the results from the deep drilling programme in northern Switzerland. Further, analogical interferences from the situation in the southern Black Forest allow predictions to be made on the anticipated block structure of the crystalline Basement. (author)

[en] Formation processes of caoline crust of weathering on garnites are accompanied with uranium evacuation (on the average 66%) and thorium (82%). Main uranium share in granites is related to accessor minerals, alterated biotite and intergranular sufures, in caoline crust of weathering - with caolinite, selvages of iron and titanium oxides and hydroxides. Two mechanisms of uranium extraction from accessor minerals exiting in parallel have been established: uranium transition to solution from edge parts of grains and microcracks and gradual solutions of minerals with transfer of all their components to the solution

[en] The DINAMIGE in the black granites exploitation project framework was carried out a serious study about mining titles which they have been required in Florida Province.

[en] This report shows the results obtained in the two first stages of the granitic massif geological -economic study around the Soca district.