Stromatoporoid growth orientation as a tool in palaeotopography: a case study from the Kadzielnia Quarry, Holy Cross Mountains, central Poland

Abstract

Growth orientation of stromatoporoids has allowed reconstruction of the palaeotopographic position of a large Frasnian organic buildup exposed in the Kadzielnia Quarry in the Holy Cross Mountains, central Poland. Two main, mature stage, stromatoporoid growth modes have been discerned: erect and semi-buried. The growth orientations of the stromatoporoids were studied in 17 sections that expose four different facies in the quarry. The inclinations of the basal surfaces of specimens and direction of the growth axes were measured and compared in terms of different growth modes, facies and positions in the organic buildup. The results support the earlier opinions that the inclined contact between the Kadzielnia stromatoporoid-coral limestones and the detrital limestones is depositional and represents an inclined depositional surface, and that the Kadzielnia buildup developed in a calm water setting below the storm wave base on a slope or at its foot. General conclusions emerging from the studies are: 1) stromatoporoid growth directions hold a key to reconstructing ancient topography; 2) erect stromatoporoids that grew on inclined surfaces changed the growth axes to the vertical direction during their growth; and 3) stromatoporoid growth directions and particularly the changing mode of growth of erect forms support the view that Palaeozoic stromatoporoids acted photosensitively.