Oxygen isotope values from high-latitudes: Clues for Permian sea-surface temperature gradients and Late Palaeozoic deglaciation

Abstract The Permian was a period of waning large-scale continental glaciations in the southern Hemisphere. The waning of these ice sheets during the Early Permian led to discharge of 18 O-depleted ice–melt water into the oceans. This, coupled with rising seawater temperatures, resulted in a concomitant decline of about 2.5‰ in the δ 18 O of seawater, as recorded by brachiopod shells from low-latitude ( δ 18 O, by about 2.5‰, than their coeval low-latitude counterparts, suggesting a Permian sea-surface temperature (SST) gradient of about 9 to 12 °C between tropical–subtropical ( δ 18 O seawater records suggest that the global warming that resulted in the waning of the Permo-Carboniferous ice sheets during the Sakmarian was followed by another cooling during the late Kungurian and by renewed warming during the Mid- and Late Permian.