CHEMOSTRATIGRAPHY OF THE FURONGIAN (UPPER CAMBRIAN) DEPOSITS OF THE SINO-KOREAN CRATON: INSIGHTS ON GLOBAL CORRELATION AND TRILOBITE EXTINCTIONS

We report a compilation of biostratigraphic data paired with new high-resolution carbonate carbon isotope data from middle to upper Cambrian strata of the Sino-Korean Craton. Within the compilation of trilobite biostratigraphy three Furongian extinction events are recognized, in stratigraphic order, between the Neodrepanura and Chuangia biozones, the Chuangia and Changsahnia/Irvingella biozones, and the Kaolishania and Asioptychaspis/Tsinania biozones. These extinctions appear to be correlative to three extinction events recorded on the Laurentia paleocontinent. The Neodrepanura extinction has been previously correlated with the global end-Marjumid extinction that occurs at the Cambrian Series 3–Furongian boundary at the onset of the Stepteoan Positive Carbon Isotope Excursion (SPICE). The Chuangia extinction is broadly correlative with the end-Steptoean extinction. The Kaolishania extinction is broadly correlative with the end-Sunwaptan extinction and occurs at the onset of a +2‰ δ¹³C excursion, which is also present in Laurentia. Until now the Steptoean and Sunwaptan extinctions have only been identified in Laurentia and the presence of correlative extinction events on the Sino-Korean Craton suggests they were global in magnitude. Furthermore, the onset of positive δ¹³C excursions at the Neodrepanura and Kaolishania extinctions suggest a common driver for these events, and the isotope data are consistent with models that postulate episodes of increased oceanic anoxia may have served as the ‘kill-mechanisms’ for these extinctions.