Earth has experienced extreme past climates, and recent studies posit a controversial hypothesis that a cold global climate, including tropical low-altitude glaciation, existed in the Pennsylvanian Period. Paleohydraulic analysis of storm-generated, hummocky bedforms in shallow marine Pennsylvanian deposits of the Ancestral Rocky Mountains of Pangea allows for reconstruction of wave parameters, which reflect paleoclimate because physical marine conditions and ocean−atmospheric linkages are highly latitude- and temperature-dependent. The results indicate large waves and gale to hurricane strength winds of cyclonic storms, driven by high Coriolis vorticity and high sea-surface temperatures. These refute both published extremely low paleolatitude (5°) estimates for the Colorado (USA) region, and the idea of a cold equatorial Pennsylvanian climate, the latter of which has profound implications for biological, geochemical, and oceanographic reconstructions.
Myrow et al. (Fri,) studied this question.