Abstract

Cumulic paleosols in core from the Lower Permian (Asselian–Sakmarian) Council Grove Group of western Kansas contain a diverse suite of pedogenic features, including carbonate nodules, gleying, fossil burrows, rhizoliths, peds, and cutans. Abundant gleying, burrowing by organisms with a high soil-moisture requirement, and extensive plant growth are evidence of at least intermittently high soil moisture during this time. Paleosol character was strongly influenced by regional topography and paleogeographic position, as well as the climate changes accompanying hierarchical glacioeustatic cycles. The distribution of pedogenic features across formations also indicates a shift toward more humid conditions during a larger 3rd-order regression.

Climatic variability during the interval of soil formation resulted in overprinting and close stratigraphic juxtaposition of both humid and arid climate indicators. Variability is likely the result of exposure to multiple 5th-order eustatic and climatic cycles during the lowstands of 4th-order cycles. Fifth-order cycles are expressed as lithologic changes in stratigraphically equivalent outcrops across the state, but lack of accommodation space prevented cycles from being expressed as differing lithologies in the study area. Biologic activity assisted in consolidation and stabilization of eolian and alluvially deposited sediments.

This study emphasizes that detailed, quantitative study of pedogenic features can reveal important paleoclimatic and paleoenvironmental information in otherwise lithologically similar paleosols. Close juxtaposition of opposing climatic indicators over intervals of known sea-level change adds evidence to the hypothesis of a link between sea-level change and climate change in the Early Permian. Pedogenic features thus support a semiarid or wetter climate for the midcontinent during the Early Permian.