Characteristics of the mantle sources and crystallization history of the subvolcanic alkaline rock series: Geochemical and Sr-Nd isotope signature (an example from the České středohoří Mts., Ohře/Eger Rift)

Continental intraplate magmatism is commonly expressed in subvolcanic complexes, for which it is important to characterize the mantle sources. That necessitates distinguishing the effect upon mantle signature of fractional crystallization and assimilation processes during magma ascent and residence in the crust before final emplacement. To achieve that goal, major, minor and trace element data, together with Sr and Nd isotope systematics will be determined. An excellent case area is provided by the subvolcanic rock association of the Roztoky Intrusive Centre, which comprises a hypabyssal low-alkali series of essexite-monzodiorite-sodalite-syenite and dykes of both high- and low-alkali character. Existing data on the genetically related basaltic lava piles and felsic intrusions of the České středohoří Mts. will provide a valuable comparison. Temperature-time profiles of individual subvolcanic rock types will be constructed using fission-track methodology on apatites.