Konkrecje fosforytowe z pstrych margli węglowiec kich (Karpaty Fliszowe) – Studium mineralogiczno-genetyczne

Abstract

PHOSPHORlTE CONCRETlONS OF THE WĘGLÓWKA VARlEGATED MARLS (CARPATHIAN FLYSCH)On the basis of mineralogical investigations the presence of phosphorite and phosphate-carbonate concretions in the Węglówka marls of Maestrichtian-Danian age was established and their mineralogical composition determined. The phosphate substance of these concretions is of francolite-kurskite composition. Among carbonate admixtures calcite, rhodochrosite and sideroplesite were found. The problem of carbonate-apatites and the genesis of concretionary pelitic clay phosphorites are discussed. In the writer's opinion they are products of early diagenetic processes; carbon dioxide and fluorine, controlling the solubility of calcium phosphates and the physico-chemical conditions of the environment, are the most important factors in their origin. The increased concentration of fluorine is to be attributed to the acid exhalations of the Upper Cretaceous volcanism strictly contemporaneous with the formation of phosphorites. Some suggestions are also advanced regarding the probable paleogeographic changes in the axial zone of the geosyncline at that time.