The Dynamic Holocene Dune Fields of the Great Plains and Rocky Mountain Basins, U.S.A.

Abstract

Publisher Summary This chapter discusses the dynamic Holocene dune fields of the Great Plains and Rocky mountain basin. Late Wisconsin glaciation, in the form of a continental ice sheet and the alpine glaciers in the Rocky Mountains, was associated with a considerably cooler climate than the present. Fauna and flora of the late Wisconsin also provide evidence of colder or at least considerably cooler conditions than at present in the northern Great Plains. The late Wisconsin floral evidence suggests that boreal spruce forest covered much of the central and northern Great Plains just prior to the retreat of the Wisconsin glacier. Very little late Pleistocene–Holocene sediments underlie the dune sand outside of the general area of the Dismal, Middle, and the North Loup rivers. In the northern and northwestern portions of the sand sea the dune sand generally rests directly on the Ogallala Group sediments. It is suggested that the climatic and other changes necessary to allow eolian sedimentation to replace alluvial sedimentation took place over the same period of time across much of the central and eastern Sand Hills but the beginning of eolian sedimentation was not necessarily synchronous throughout the entire area.