Addendum to the chemostratigraphy of the uppermost Callovian–middle Oxfordian interval of the Tethyan Fatricum domain (Tatra Mts, Krížna Nappe, southern Poland)

Abstract

New isotope (δ¹³C, δ¹⁸O of bulk carbonates) and carbonate content data from the uppermost Callovian–middle Oxfordian radiolarites of the Fatricum domain belonging to the north-western segment of the Tethys are added to previously published data. The new data supplement the Długa Valley section, the most nearly complete Bajocian–lower Tithonian section of the Krížna Nappe in the Tatra Mts. The uppermost Callovian and Lower Oxfordian bulk δ¹³C values (from 3.1 to 3.3‰) remain nearly constant with highly positive values. Therefore, the positive excursion identified in bulk carbonate δ¹³C values is interpreted as a record of the upper Callovian–middle Oxfordian global phenomenon. In this interval, a significant increase of CaCO₃ content is recorded, which accompanies facies change from ribbon radiolarites with siliceous shale partings to calcareous radiolarites with rare shale intercalations. The abrupt CaCO₃ increase may reflect a turning point in Early Oxfordian carbonate production and recovery of the marine carbonate factory.