Application of the Fujita-Ziegler paleoclimate model: Early Permian and Late Cretaceous examples

The Fujita-Ziegler model is a new semi-quantitative technique for reconstructing atmospheric circulation and resulting rainfall patterns of the geological past using uniformitarian assumptions. In this paper, we evaluate the performance of the model when applied to geographic and climatic conditions that were significantly different from the Recent. A Late Cretaceous (Maastrichtian) reconstruction permits a test of the performance of the technique during a time that apparently lacked polar ice caps and steep latitudinal temperature gradients. An Early Permian (Sakmarian) reconstruction is used to evaluate the performance of the technique when the equator-to-pole temperature gradient was steep, more like today, but all major land masses had merged to form one large supercontinent, Pangea. For both the Maastrichtian and Sakmarian, the model produced more detailed retrodictions of surface air pressure and precipitation continuity than previously published paleoclimate reconstructions. The results compare favorably with the known distribution of climatically sensitive sediments such as coals, evaporites, and phosphorites. Although the model considers complex relationships among land and sea distribution, air pressure, surface winds, ocean currents, and specific precipitation mechanisms, it is still relatively simple and easy to apply. Therefore, it is an excellent learning tool for the student of paleoclimate and should be an important technique to complement other methods of paleoclimate reconstruction.