Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
Interpretation of chemistry of the Kouty type granites (the Melechov massif of the Moldanubian Pluton)
Abstract
Published as well as archived whole-rock chemistry data of the Kouty type granite from the Melechov massif s.s. (Moldanubian Batholith) have been evaluated. The samples can be divided into two groups. The first group includes rocks in areas between the Melechov stock and the Lipnice granite, and also to the SE of the Lipnice type occurrences. Granites from this group have higher contents of K, Ti, Sr, Zr, Y and REE, a higher Zr/Y ratio, as well as lower Na and Sn contents and Sr/Eu ratios. Additional samples which are close to fuzzy contacts with the metamorphic rocks also resemble this group. Gradual transitions from this group to the Lipnice type are probable. Compositional differences between the Kouty and Lipnice types have their origin in the granitised material. The second group forms the western part of the massif. A higher fractional crystallization is expressed there in decreasing amounts of Mg, Fe, Sr, Zr and REE, a decreasing Zr/Y ratio, and an increasing Sr/Eu ratio. The source of the Melechov type granite magma, which intruded into the Kouty type, could not have evolved from the source of the Kouty type via fractional crystallization. This is because the Melechov type has a significantly higher Sr content and Eu/Eu* ratio. The author supports the hypothesis that the Kouty (and Lipnice) granite types represent, at most, only slightly migrated melt (the vicinity of the Melechov stock is an exception).
