Roaming the Rocky Mountains and Environs: Geological Field Trips
Prepared following the 2007 GSA Annual Meeting in Denver, Colorado, these 15 guides illustrate the latest geological and archeological thinking on a variety of current research themes. Regional-scale topics include landscape responses to dynamic processes of volcanism and uplift in Yellowstone and western Colorado, geomorphic evolution along the Front Range of Colorado and on the High Plains of South Dakota, and geoarchaeological research in central Colorado and western Nebraska. A series of papers illustrates tectonic and stratigraphic processes through time and space, with discussions of Precambrian structures in western Colorado, Jurassic deposition in south-central Colorado, and near-shore stratigraphic patterns in the Cretaceous strata of the Book Cliffs. One paper reviews potential seismic signatures in Cretaceous and Early Tertiary strata in northern Wyoming and Montana, and another discusses patterns of extension in southern Nevada and adjacent portions of California. Other topics in this well-rounded volume include the history of volcanism and gold mineralization at Cripple Creek, development of coalbed methane resources in the Powder River Basin, and a long-lived subsurface coal fire in western Colorado. Follow in the footsteps of these field trips, and see for yourself the patterns and evidence discussed.
Geoarchaeology of the Clary Ranch Paleoindian sites, western Nebraska
Published:January 01, 2008
David W. May, Matthew G. Hill, Adam C. Holven, Thomas J. Loebel, David J. Rapson, Holmes A. Semken, Jr., James L. Theler, 2008. "Geoarchaeology of the Clary Ranch Paleoindian sites, western Nebraska", Roaming the Rocky Mountains and Environs: Geological Field Trips, Robert G. Raynolds
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This field trip addresses multidisciplinary field research conducted since 2001 in Ash Hollow basin at both archaeological sites and cut bank exposures. Six lithostratigraphic units (I through VI, from oldest to youngest) are recognized in alluvium near the base of the valley fill below the 18-m-high Terrace 2 in the basin. Unit I is presumably Late Wisconsin, while units II through VI are early Holocene alluvial units comprised of silt loam and distinguished on the basis of color, sedimentary structures, and texture. Unit V contains the cultural material (multiple components at both archaeological sites), and was deposited at a rate of between about 0.1 and 1.5 cm/year, based on calibrated radiocarbon ages of charcoal in cut bank exposures. With such rapid rates of sedimentation, artifacts at both the Clary Ranch site (25GD106) and O.V. Clary site (25GD50) were well preserved. Landscape evolution is reconstructed in the context of the Late-Paleoindian components at the two archaeological sites.
Keywords: geoarchaeology, Early Holocene, Nebraska, Paleoindian.