GEOCHRONOLOGY AND PEDOLOGY OF BURIED PALEOINDIAN LANDSCAPES IN LARGE KANSAS STREAMS

A recent study of the effects of late Quaternary landscape evolution on the archaeological record in valleys of large Kansas streams documented widespread, deeply buried Paleoindian landscapes represented by paleosols in terrace fills. Also, buried Paleoindian landscapes were recorded in alluvial fans on the margins of valley floors of large rivers in western Kansas.

Over 50 localities were investigated along a steep bio-climatic gradient extending from the moist subhumid forest-prairie border of eastern Kansas to the dry subhumid and semi-arid shortgrass prairie of western Kansas. A suite of nearly 200 radiocarbon ages indicates that most large streams, including the Neosho, Chikaskia, Smoky Hill, Solomon, Pawnee, and Cimarron rivers, were characterized by slow aggradation accompanied by cumulic soil development from ca. 11,500 to 10,000 ¹⁴C yrs B.P. In the valleys of some large streams, such as the Ninnescah and Saline rivers, these processes continued into the early Holocene. Rapid alluviation during the middle and/or late Holocene resulted in deep burial of pedo-complexes that may harbor Early, Middle, and Late Paleoindian cultural deposits. In many valleys, the Paleoindian landscapes are 5-12 m below surface. Hence, the paucity of recorded stratified Paleoindian sites is probably related to poor visibility (i.e., deep burial) instead of limited human occupation in the valleys of large streams during the terminal Pleistocene and early Holocene. This interpretation is supported by the recent discovery of stratified Late Paleoindian cultural deposits 8-10 m below a terrace surface in the valley of lower Mill Creek, a large tributary of the Kansas River.

In sum, the thick, dark, cumulic A horizons of soils representing buried Paleoindian landscapes in the valleys of large Kansas streams are distinct stratigraphic markers that can be targeted in archaeological surveys employing deep exploration methods, such as coring, trenching and stream-bank inspection. This soil-stratigraphic approach has great potential for shedding new light on the early archaeological record of Kansas and the Central Plains.