Ordowickie akritarchy bloku górnośląskiego

Lower Palaeozoic sediments of the Upper Silesia Block have not been equally well investigated. Lower Cambrian sediments found in the southern and eastern marginal parts are so far best recognized. Sediments younger than Lower Cambrian (Middle Cambrian and Ordovician) are documented only in some boreholes. This paper presents new data about the distribution of Ordovician acritarch assemblages in this area. Ordovician microfossils were documented in three boreholes: 45–WB, 43–WB and 24–WB. In case of the latter, they represent the first stratigraphic record. The oldest assemblages of Llanvirn age were recorded in the borehole 43–WB. The Llanvirn and Caradoc sediments may also occur in the borehole 24–WB. Acritarchs known mainly from Middle Ordovician–Caradoc occur in the profile 45–WB. The microfossil assemblages recorded in Ordovician sediments of the Upper Silesia Block show mixed character, with genera and species typical for both Baltic and Mediterranean provinces.