FIRST CONTINUOUS FURONGIAN (LATE CAMBRIAN) CARBON ISOTOPE EXCURSIONS FROM THE EASTERN SINO-KOREAN (NORTH CHINA) BLOCK

Late Cambrian witnessed rapid changes in the global carbon cycle, which is preserved in the geologic record as the form of major carbon perturbations. The Furongian series contain two key carbon excursions, the SPICE (Steptoean Positive Isotopic Carbon Excursion) and the TOCE (Top of Cambrian Excursion), also known as the HERB (Hellnmaria-Red Tops Boundary). We report these Furongian carbon isotope excursions from the Sesong and Hwajeol formations deposited in the inner to outer shelf environments of Taebaeksan Basin, Korea, located in the easternmost margin of the Sino-Korean (North China) Block. We integrated detailed facies analysis, trilobite and conodont biostratigraphy and isotope chemostratigraphy from one 210 m-thick drill core and three supplementary outcrop sections. Carbon isotope data of the studied intervals have a major positive excursion of magnitude 4.78‰ (-1.97 to +2.81) in the lower Paibian interval (about 45 m), and a major negative excursion of magnitude 5.61‰ (-0.58 to -6.19) in the base of conodont Eoconodontus notchpeakensis Biozone corresponding to the middle part of stage 10 (about 5 m). In addition, a few minor negative excursions are recorded between these two major excursions. The carbon isotope pattern show pre-SPICE, rising limb, plateau, and falling limb of SPICE, and minor excursions in the post-SPICE, then TOCE, respectively.

Previous studies of Furongian carbon excursions of the Sino-Korean Block show that except for the Liaoning Province, the SPICE was not clearly reported across the North China, while the TOCE was only partially reported from Jilin Province (Dayangcha section). The present continuous carbon isotope data from late Miaolingian through Furongian from the Taebaeksan Basin, Korea, would provide major reference for regional and global correlation.