BOUNDING DISCONTINUITIES IN SUSQUEHANNA VALLEY ALLUVIUM - USING STRATIGRAPHY TO RECONSTRUCT PREHISTORIC LANDSCAPES AND ARCHAEOLOGICAL SITE FORMATION

The alluvial deposits of the North Branch of the Susquehanna River represent an archive of environmental change as well as a repository of artifacts and cultural features made by prehistoric people. While many local factors affected how frequently the river flooded and when it stored sediment within the valley, stratified archaeological sites exhibit remarkably consistent discontinuities that bound discrete packages here referred to as members of the Wyoming Valley alloformation. Bounding surfaces have been traced through 23 sections of both culturally sterile alluvium and archaeological excavation profiles. The latter include some Paleoindian as well as Early Archaic contexts.

Micromorphology of soils that formed on upper bounding surfaces, x-ray diffraction analyses of clay minerals formed by weathering under particular Holocene climates, and magnetic mineralogy of both inherited and pedogenic magnetic phases provide a framework for correlation throughout the valley from Binghamton, New York downstream to Harrisburg, Pennsylvania. A total of 139 radiocarbon dates constrain the age of the bounding surfaces, and calibration to calendar years suggests some human presence by at least 13,000 years before present.