Skały silikoklastyczne górnego arenigu (volkhov) z otworu wiertniczego B5–1/01 (N Polska)

Two silicoclastic beds separated by the 0.75 m thick bed of marly limestone were discovered inside the upper portion of the section of Pieszkowo Red Limestone Formation in the offshore B5–1/01 borehole (Fig. 1). The lower bed (0.2 m thick) consists of brownish-grey limy sandstones with intraclasts. The upper one (0.25 m thick) is represented by light grey quartz sandstones and limy quartz sandstones with glauconite. The beds under study belong to theMegistaspis limbata Trilobite Zone (Late Arenig) and can be the equivalent of quartz sandstones in the carbonate Kriukai Formation in western Latvia (Figs 2, 3). The Latvian sandstones are known as “Volkhov collector” and considered a potential hydrocarbon reservoir (Todorovskaya et al., 1976; Laškov & Vosilus, 1987).