High-resolution integrated conodont biostratigraphy and carbon isotope (δ13Ccarb) chemostratigraphy of the Ordovician of Sweden, with comparison to South China and North America

Based on the new Kinnekulle-1 core from the classical Kinnekulle Table Mountain, this study provides an integrated high-resolution biostratigraphic and chemostratigraphic framework for the late Early through Late Ordovician of southern Sweden. The studied succession is 115.8 m thick and composed largely of limestone and argillaceous limestone with subordinate mudstone and shale. Based on 140 conodont samples, 14 conodont zones and five subzones were identified, spanning from the Oepikodus evae zone in the latest Floian (stage slice Fl3) through the Amorphognathus ordovicicus zone in the Hirnantian (Hi2). The new zonation supports a highly resolved carbon isotope stratigraphy based on 844 samples. This unusually condensed succession includes many of the carbon isotope anomalies crucial for intercontinental correlation, but also several associated with significant stratigraphic gaps. The resulting chemostratigraphy includes the basal Dapingian negative isotopic carbon excursion (BDNICE), parts of the middle Darriwilian isotopic carbon excursion (MDICE), the Lower Sandbian negative isotopic carbon excursion (LSNICE), parts of the Sandbian isotopic carbon excursion (SAICE), parts of the Guttenberg isotopic carbon excursion (GICE), the Moe (Whitewater) excursion, provisionally the Paroveja excursion, and the Hirnantian isotopic carbon excursion (HICE), the latter associated with brachiopods of the Hirnantia Fauna. We integrated this new record with previous records from the area to provide a coherent Ordovician carbon isotope stratigraphy for southernmost Scandinavia, for further comparison with the East Baltic carbon isotope zonation and key sections in South China and North America. The study identifies and discusses significant challenges with global chemostratigraphic correlation in the Upper Ordovician.