High-resolution carbon isotope (δ13Ccarb) chemostratigraphy of the lower Permian from the US midcontinent: Checking the pulse of the late Paleozoic ice age

High-resolution stable isotope chemostratigraphy (delta C-13(carb) and delta O-18) from the Asselian and Sakmarian stages (Cisuralian Series, Permian System) was carried out on the Newby 2-28R core from Stevens County, SW Kansas. The cyclothemic strata of the Council Grove and Chase groups sampled in this study record the rapid rise and fall of sea level due to the expansion and contraction of glacial mass during the early Permian in the waning phases of the late Paleozoic ice age. Lithologies interpreted to be deposited during higher sea-level stand consistently show elevated delta C-13(carb) values when compared with shallower-water parts of each cycle and show as much as a 6.0% shift in delta C-13(carb) within single cycles. The delta C-13(carb) values recorded here mirror changes in sea level throughout the sampled interval, indicating a close correspondence between at least the local carbon cycle of the U.S. midcontinent and Anadarko Basin with global ice-sheet dynamics and eustatic sea level. As has been seen in previous studies, however, this basin contains generally lower absolute values of delta C-13(carb) compared to other basins, such as those in Russia (Moscow Basin), China (Yangtze Platform), and Nevada (Great Basin). The data presented here represent the first high-resolution analysis of carbon cycle dynamics during the early Permian, and it remains to be seen if the heartbeat of the late Paleozoic ice age preserved in this region is recognizable globally.