COMPARATIVE EARTH HISTORY AND LATE PERMIAN MASS EXTINCTION

The repeated association during the late Neoproterozoic Era of large c arbon-isotopic excursions, continental glaciation, and stratigraphical ly anomalous carbonate precipitation provides a framework for interpre ting the reprise of these conditions on the Late Permian Earth. A pale oceanographic model that was developed to explain these stratigraphica lly linked phenomena suggests that the overturn of anoxic deep oceans during the Late Permian introduced high concentrations of carbon dioxi de into surficial environments. The predicted physiological and climat ic consequences for marine and terrestrial organisms are in good accor d with the observed timing and selectivity of Late Permian mass extinc tion.