Abstract On this field trip, you will visit two important archaeological cave sites that provide the most compelling evidence for latest Pleistocene and earliest Holocene human occupation in the Bonneville Basin. Danger Cave, located near Wendover, Utah/Nevada, is famed for its deeply stratified archaeological deposits dating as old as 10,300 radiocarbon yr B.P., when the remnant of Lake Bonneville stood at the Gilbert shoreline. Bonneville Estates Rockshelter, located south of Danger Cave at the Lake Bonneville highstand shoreline, also contains well-preserved stratified deposits, including artifacts and cultural features dated to at least 11,000 radiocarbon yr B.P., making it one of the oldest known archaeological occupations in the Great Basin. We describe results of our recent research at these sites and show the stratigraphic evidence for these earliest human occupations. We also review recent work at the Old River Bed Delta, on Dugway Proving Ground, that has documented hundreds of Paleoarchaic occupation sites dating 11,000–8500 radiocarbon yr B.P. Together these localities give us an unparalleled picture of human occupation during the first few thousand years of known human occupation in the region, during a time of dramatic environmental change. Packrat middens, pollen sampling localities, and geomorphic features that illustrate the history of Pleistocene Lake Bonneville and the environmental history of the western Bonneville Basin will also be observed on this trip .

Abstract Donald R. Currey spent over two decades researching and exploring relics of ancient Lake Bonneville in the eastern Great Basin. Shoreline and deepwater deposits of Lake Bonneville document coastal processes, lake chemistry, and environmental change during the late Pleistocene and Holocene. This field guide summarizes findings at many of the classic localities researched by Currey and colleagues that contributed to the current understanding of this impressive pluvial lake and its interglacial successor, Great Salt Lake. Subjects include coastal processes at Antelope Island and the Stockton Bar; lake history, chemistry and environmental change at Stansbury Island, the Public Shooting Grounds and Hansel Valley; deltaic depositional processes at Big Cottonwood Canyon, American Fork Canyon and Brigham City; and the relative chronology of glacial and lacustrine deposition at Little Cottonwood Canyon and Bells Canyon.

Abstract Playas are among the most common of desert landforms, with more than 50,000 worldwide and with great variation in size and physical characteristics. They range from a hectare or less to hundreds of square kilometers, and they may support aircraft landings or be totally impassable to land vehicles. Because they possess distinctive physical attributes and are common elements of arid and semiarid landscapes, which occupy nearly 30% of the Earth's land surface, they have had significant effects on military history and operations for centuries. This significance is not apt to diminish. The single most important determinant of playa-surface conditions is the combination of surface and ground-water hydrology. Playas with ground water that is sufficiently deep to preclude capillary rise favor hard surface crusts. Prolonged capillary or direct ground-water discharge in arid environments readily builds up evaporite mineral assemblages including halite, gypsum, and calcite. Changing hydrologic conditions resulting either naturally or from human activity, for example, ground-water extraction, can result in alteration of relief and surface hardness of playas over both short- and longer-time spans. Military use by ground forces includes both expeditious and evasive maneuvering of ground vehicles. Air and spaceborne vehicles, including fixed and rotary wing craft and spacecraft, have used numerous playas in their natural state as landing platforms, and many other playas are readily available in remote, unpopulated areas of the globe. Future uses are apt to take advantage of the unique attributes of this arid-region feature—the flattest of all landforms.