IMPLICATIONS OF A LOWER PENNSYLVANIAN ULTISOL FOR EQUATORIAL PANGEAN CLIMATES AND EARLY, OLIGOTROPHIC, FOREST ECOSYSTEMS

A well-formed, upland soil profile, preserved beneath the Lower Pennsy lvanian, Lykens Valley #2 coal in the Southern Anthracite Field of nor theastern Pennsylvania, is geologically the oldest example of an Ultis ol yet identified, The Lykens Valley paleosol is a complete soil profi le that exhibits characteristics consistent with a sustained period of soil formation in a highly oxidizing and leaching upland environment, This paleosol provides evidence that an active and complex forest eco system occupied tropical uplands at a time when coal formation dominat ed the adjacent lowland environments, In addition, it provides insight s for understanding the evolution of land plants, the development of o ligotrophic, terrestrial ecological interactions, and global carbon cy cling. The distribution of kaolinite, illite, chlorite, and aluminum a nd iron hydroxides within the profile shows that this paleosol formed in a warm, moist, oxidizing environment, Further, on the basis of mode rn analogs, this profile suggests that a stable substrate may have per sisted for as long as a hundred thousand years, The formation of Ultis ols during the Lower Pennsylvanian demonstrates that plant communities had complex rooting systems that were capable of collecting nutrients and surviving in a base-poor and well-drained environment at a much e arlier time than previous Upper Pennsylvanian estimates, The existence of a viable, upland-forest plant community greatly increases the land area available for terrestrial primary productivity and carbon pumpin g in equatorial Pangea and should thus have a major impact on global c limate during the Lower Pennsylvanian.