Development of the Turonian Conulus Lagerstätte in the Wielkanoc quarry, Miechów Upland (South Poland)

Abstract

Geneza nagromadzenia jeżowców rodzaju Conulus w skondensowanej warstwie wapieni turońskich w kamieniołomie Wielkanoc (południowa Polska) Turonian sandy limestones and organodetrital limestones exposed in the Wielkanoc quarry, Miechów Upland, South Poland, lie on Oxfordian massive limestones, truncated with an abrasion surface. The bed situated ca. 2.5 m above the abrasion surface contains a parautochthonous and monotypic assemblage of the species Conulus subrotundus Mantell, 1822; thus the concentration can be referred to as the Conulus Lagerstätte. The microfacies analysis of the Conulus Lagerstätte indicates its development to have been determined by the existence of eco-events producing an increased population of Conulus subrotundus, and of sedimentological factors, that is waning of the loose sediment from the sea floor and erosion of the consolidated deposit rich in the earlier fossilised echinoids. The episodes of material accumulation, its consolidation and erosion in high-energy environment (action of bottom current) led to the increase of amount of echinoids as the intraclasts according to the model of lag sediment deposition.