Sedimentary record of subaerial volcanic activity in the basal Ordovician shoal-marine deposits: the T enice Formation of the Prague Basin, Bohemian Massif, Czech Republic

The basal Ordovician T enice Formation represents an initial member of the preserved infill of the Prague Basin. Volcanic admixture in sediments preserved in the south-western part of the basin suggests subaerial volcanic activity during the deposition of the T enice Formation. Three principal lithofacies associations were defined within sedimentary record of the T enice Formation based on petrography and observed sedimentary structures: i) graded conglomerates, ii) lithic sandstones and iii) volcanigenic deposits. The studied sediments were mostly deposited as subtidal sand dunes, locally interbedded with volcaniclastic rocks. They are considered deposits of a marine lower shoreface influenced by ebb-tide currents. Volcaniclastic intercalations are interpreted as deposits of debris flows and turbidity currents that redeposited volcaniclastic material derived from subaerial K ivoklát-Rokycany and Stra ice volcanic complexes.