Record details

    Geochemistry of the stratified volcanosedimentary complex in the central part of the České středohoří Mts., North Bohemia
    Balogh, K.
    Cajz, Vladimír
    Erban, V.
    Ulrych, Jaromír
Publication type
    článek v odborném periodiku
Source title - serial
    Roč. 27, -
    s. 27-49
    Projekt: IAA3111601, GA AV ČR
    Projekt: T014961 and T029897, Hungarian Science Foundation Projects Nos., HU
    Rozsah: 23 s.
    Výzkumný záměr: CEZ:AV0Z3013912
Subject category
    České středohoří Mts.
Abstract (in english)
   On the basis of a new volcanological model and geochemical investigation in the České středohoří Mts., the following volcanostratigraphic formations were recognized: (i) the Lower Fm. - lavas and volcaniclastics of basanitic character (36-26 Ma; Mg# = 57-76; 87Sr/86Sr = 0.703128 -0.703526 and 143Nd/144Nd = 0.512738-0.512849) corresponding to primitive upper mantle products; (ii) the Upper Fm. - lavas and volcaniclastics of trachybasaltic type (31-25 Ma; Mg# = 41-58 87Sr/86Sr = 0.704428-0.704649 and 143Nd /144Nd = 0.512679-0.512742) representing differentiated and partly crustal-contaminated evolved products; (iii) the Uppermost Fm. - flow(s) of basanite (24 Ma), similar in geochemical characteristics to those of the Lower Fm. Volcaniclastic products of the Lower Fm. (Mg# = 51-69) and the Upper Fm. (Mg# = 45-51) also substantially differ in bulk composition. The volcaniclastics underwent alteration to a different degree, which has significantly changed their geochemical signatures.
   Enrichment and depletion in elements, normalized to the massive rocks of the same formation, are highly variable. However, contents of Ti, Al, Si, Fe and (Mn) are relatively stable and these elements represent typical immobile components, whereas Ca, Na, K and Mg contents are Lower; contents of H2O and CO2 are significantly higher. Trace elements such as Nb, Ta, Zr, Hf, REE and Y seem to behave as immobile, whereas Sr, Cu, Ni, Co, Cr, (Th, U) as mobile. The alteration products are mostly represented by minerals of the smectite and zeolite groups.
    AV ČR Brno, Geologický ústav
Contributor code
    AV ČR, GLÚ
Source format
Import date
    8. 8. 2012