Record details

    Petrophysical and geochemical constraints on alteration processes in granites
    Janoušek, Vojtěch
    Machek, Matěj
    Petrovský, Eduard
    René, Miloš
    Roxerová, Zuzana
    Staněk, Martin
Publication type
    článek v periodiku
Source title - serial
    Studia geophysica et geodaetica
    Roč. 57, č. November
Thesaurus term
    petrophysical properties, AMS, density, porosity, geochemistry, greisenization, Krudum Granite Body (KGB)
Abstract (in english)
   The hydrothermal alteration of granites has large influence on their petrophysical properties. To reveal the impact of alteration on magnetic and porosity properties of granites we have conducted a complex study of effects of two largely independent alteration processes, related to chemically different fluids, in granites of the Vysoký Kámen stock (the Krudum granite body, Czech Republic). It includes the whole-rock geochemical, magnetic and pore-space characterization. The alkali feldspathization resulted in decomposition of Li-mica, quartz removal, depletion in mafic cations and growth of new alkali feldspars (albite, K-feldspar), decreasing the overall magnetic susceptibility and disrupting the pore space by its discontinuation. The preservation of anisotropy of magnetic susceptibility (AMS) pattern is likely connected with insignificant influence of the feldspathization process on the paramagnetic a diamagnetic phases orientation acquired during the magma emplacement. The greisen
   ization, on the other hand had considerably more significant effects on microstructure and physical properties of the granite. The microstructure was modified by the growth of large amounts of new phases (lithium mica, quartz and topaz). This changed the mineral density of the rock, the porosity, size and character of pores to larger, flatter and probably more connected. This led also to the complete reworking of the original AMS during the greisenization.
    Česká geologická služba
Contributor code
    ČGS (RIV)
Source format
Import date
    15. 10. 2014