Upper Visean conodonts from Orlej in the Cracow Upland: stratigraphical and paleothermal implications

Abstract

The conodont fauna from the Upper Vis¾an deposits of the Cracow Upland, contacted by the subvolcanic porphyry intrusion, and exposed at the Orlej Quarry includes stratigraphically important forms, indicative of the Gnathodus girtyi collinsoni Zone. The conodont-bearing algal-foraminiferal boundstones in their postdepositional history underwent the thermal influence of the porphyric intrusion of Zalas. The employment of conodont alteration index (CAI) indicates that the layer of algal-foraminiferal boundstones occurring 80 m off the contact with intrusion was heated over a temperature of 210° C during the period not shorter than 800 years.