Record details

Title
    Textures of rare-metal granites as exploration tool
Statement of responsibility
    Reimar Seltmann, Miroslav Štemprok
Author
    Müller, Axel
    Seltmann, Reimar
    Štemprok, Miroslav
Language
    anglicky
Source title - monograph
    31st International Geological Congress: abstracts Volume
Pages
    s. [1]
Notes
    Kopie z CD-ROM 31st International Geological Congress, Rio de Janeiro - Brazil, August 6-17-2000 - Abstracts Volume, Sg 605e.pdf
Subject group
    degazace
    granit
    intruze
    kontakt
    kovy vzácné
    krušnohorský pluton
    krystalizace
    metalogeneze
    morfologie
    rudy Sn
    rudy W
    struktury
    těkavé látky
Geographical name
    Cínovec (Teplice)
    ČR-Čechy
    Francie
    Portugalsko
    Rusko
Keyword
    Exploration
    Granites
    Rare-metal
    Textures
    Tool
Abstract (in english)
   Bodies of mineralized rare-metal (RM) granites are commonly interpreted from geophysical data (gravity, magnetics, seismics) as horizontal or moderately inclined plates connected with the sources of felsic magmas by thin steep feeding channels. Recognizing the nature of upper contacts of these bodies is of importance for mineral exploration as they host most of the deposits of granitic affiliation (Sn, W, Mo, Nb, Ta, Be, Cs, Rb). Apical parts of granitic bodies of plutonic and batholith size contain in places fine-grained porphyritic and/or aphyric granites, two-phase and aplitic granites as well as specific pegmatitic rims (stockscheiders). Even small granite cupolas are formed by two or more magmatic pulses whose products are commonly overprinted by postmagmatic or late magmatic alterations.
   The crystallization of the granites near the upper contact is characterized by rapid cooling and loss of volatiles, thermal contraction, oscillation growth (manifested on quartz by CL), repeated brecciation and metasomatic pervasive and joint controlled alterations related or unrelated to ore mineralizationsThe complex origin of granite textures along the upper contacts is caused not only by the temperature gradient at the time of intrusion across the contact zone and a sudden release of pressure but also by the later emplacement of younger granites along the upper contact of solidified granites and massive alterations caused by orthomagmatic and meteoric fluids circulating in fissures and joints of solid granites.
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    11. 10. 2007
Import date
    8. 8. 2012