Global Upper Ordovician correlation by means of δ13C chemostratigraphy: implications of the discovery of the Guttenberg δ13C excursion (GICE) in Malaysia

Abstract Apart from a single study of the early Katian δ13C chemostratigraphy in two regions in China, no investigations of the Sandbian and Katian chemostratigraphy have been published from anywhere in Asia. A recent study of the conodont biostratigraphy of the classical Ordovician succession on Langkawi Islands, peninsular Malaysia, showed the presence there of strata coeval with those having the Guttenberg Carbon Excursion (GICE) on the Yangtze Platform. In an effort to establish for the first time the presence of this widespread δ13C excursion in southern Asia, a series of samples from the upper part of the Kaki Bukit Formation was isotopically analysed. This resulted in the discovery of a conspicuous δ13C excursion with peak values of ~ 2 ‰ above the baseline values. The excursion is located just above theBaltoniodus alobatusSubzone and near the level of the first appearance ofHamarodus europaeus, hence the same stratigraphic position as the GICE on the Yangtze Platform. Using the GICE, the Malaysian study interval is closely correlated with the GICE intervals at three localities representing an approximately 23 000 km long transect from Malaysia across Baltoscandia to central North America. This shows the usefulness of δ13C chemostratigraphy to clarify previously obscure stratigraphic relationships between geographically very widely separated localities.