The study of the Berkha Island reef massif (Novaya Zemlya), based on lithological and geochemical data

Abstract The geological structure of the Berkha Island is a high-level biogenic buildup – a reef massif. It is a paragenetic facies combination including a reef plateau, a reef core, a buttress, a forereef and pinnacles. The development of this reef massif continued for about 30 Ma. The reef growth started in the Late Visean with formation of mud bank and vanished in the Late Bashkirian with formation of solitary tower-shaped pinnacles. Geochemical methods showed high purity of reef carbonates and proved the existence of subaerial exposures during the formations of the reef massif. According to the petrochemical module analyses, enables to suggest progressive climate aridization with time, confirmed by geological data: there is a coeval anhydrite strata to the south of Berkha Island. The combination of positive lithological, structural and paleoclimate factors raises the evaluation of the hydrocarbon potential of the area; moreover, the presence of solid bitumen has been reported from forereef facies of Berkha Island.