Podrobnosti záznamu

    Trace element composition of quartz from the Variscan Altenberg-Teplice caldera (Krušné hory/Erzgebirge Mts, Czech Republic/Germany): Insights into the volcano-plutonic complex evolution
    Ackerman, Lukáš
    Breiter, Karel
    Svojtka, Martin
    Švecová, K.
Typ dokumentu
    článek v odborném periodiku
Zdrojový dokument - seriál
    Chemical Geology
    326/327, 9 October
    s. 36-50
    Projekt: GAP210/10/1105, GA ČR3cav_un_auth*0263315
    Rozsah: 16 s. : WWW
Předmětová kategorie
    Laser-ablation ICP-MS
    Ti-in-Quartz thermobarometry
    Variscan magmatites
Klíčové slovo
Abstrakt (anglicky)
   The internal structures and appropriate trace-element distribution of quartz grains were studied using laser ablation ICP-MS technique combined with a hot- and scanning cathodoluminiscence analysis. Studied Variscan magmatic suite is located in the Altenberg-Teplice Caldera (eastern Krušné Hory/Erzebirge - along the Czech Republic/Germany border) and is composed from co-magmatic volcanics (peraluminous basal rhyolite and associated dacite, overlying three units of subaluminous Teplice rhyolite and granite porphyry), and plutonic granites (two intrusions of A-type biotite and zinnwaldite granites). The trace-element distribution in granite prorphyry and rhyolite quartz shows distinct zonality in cathodoluminiscence images and chemical compositions: core is poor in Ti, outer rim zones enriched with Ti, whereas Al records an opposite trend. In contrast, quartz from granites are very weakly zonated or homogenous.
   Based on the chemical composition of quartz and their zoning, we assume that quartz crystals began to crystallize gradually in the primary deep-seated magma chamber with P-T condition of 750 °C and 10 kbar in an environment with increasing concentration of Al and decreasing concentration of Ti. Early stage was followed by subsequent adiabatic ascent into the shallow magma chamber (estimated by Ti-in-quartz thermobarometry at ca. 700 °C, 2 kbar; ) during which crystal rims rich in Ti originated and then extruded. After caldera collapse, part of the magma intuded as granite; and in the environment of residual melt rich in water and flux agents, grew later in form of snowball-quartz with a high content of Al and low Ti.
    AV ČR Brno, Geologický ústav
Kód přispěvatele
    AV ČR, GLÚ
Zdrojový formát
Datum importu
    19. 3. 2014