Major element geochemistry of Neoproterozoic successions of Varanger Pensinsula, North Norway, and Sredni and Rybachi Peninsulas, North- west Kola, Russia: provenance patterns and basin evolution

Abstract

Major element analyses of 461 samples of Neoproterozoic sedimentary rocks were classified by using petrochemical plots and statistically treated in cluster analyses. In general, the studied siliciclastic rocks represent two major associations. The first contains arkoses to quartz arenites with predominantly illitic shales; it includes the majority of the studied formations and may be interpreted as a product of denudation of the continental crust. The second association comprises greywackes and lithic arenites associated with shales which contain some chlorite and Na-feldspars. The chemistry suggests that there was a contribution from a basic, Na-rich crust or volcanic source. The geochemistry is in accord with interpretations of sedimentary environments and basin development based on other methods. It also indicates a temporarily cold and dry climate which is compatible with sedimentary facies analysis and the fact that there was no continental vegetation. Formations which are represented by interbedded variegated siliciclastic and carbonate rocks and exhibit traces of evaporites constitute another important climatic indicator.