A study of 8 depositional sequences along an outcrop transect from southern Kansas to western Iowa reveals 2 distinct types of sequence boundaries. Wet climates produce sequence boundaries with large incised valleys infilled with fluvial sandstone to estuarine mudstone. It is infilled with fluvial conglomerate and sandstone through estuarine mudstone. In addition, coals are common at the sb and within the valley fill indicating high paleowater tables. Drier climates produce sequence boundaries with incised valleys that are narrower and shallower, typically a few hundred meters wide and up to 10 m deep.
Coals are absent and plant assemblages are dominated by conifers.
Examples include the Captain Creek Ls. And Stanton Ls. incised valleys. These valleys are typically infilled with a lower limestone conglomerate, locally derived from adjacent valley walls, followed by a thin upper estuarine mudstone to siltstone facies. The interfluve paleosol in the Stanton Ls., and Aridisol, confirms that the sb formed in a dry climate. Our study provides a model by which incised valley systems can be interpreted both in terms of sea-level history and climate.