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Full-Text Articles in Physical and Environmental Geography
Radiocarbon Chronology And Δ13c Analysis Of Mid-To Late-Holocene Aeolian Environments, Guadalupe Mountains National Park, Texas, Usa, David Wilkins, Donald Currey
Radiocarbon Chronology And Δ13c Analysis Of Mid-To Late-Holocene Aeolian Environments, Guadalupe Mountains National Park, Texas, Usa, David Wilkins, Donald Currey
David E. Wilkins
The Red Dunes of Guadalupe Mountains National Park are quartzose sand sheets and dunes stabilized by sparse plant cover. Stratigraphy, radiocarbon dating, and δ13C analysis were examined in two of the larger arroyos for correlating evidence of aeolian deposition, which in this basin is taken as an indication of arid conditions. Four quartz-sand lithostratigraphic units, representing intervals of aeolian activity, are identified. Radiocarbon dates provide constraint on the timing of the three youngest quartz-sand units. A mid-Holocene aeolian interval, represented by a single radiocarbon date of 6350± 70 BP, is interpreted as transitional to an altithermal regime. A neopluvial period, …
A Two-Component Aggregation Model, Thomas A. Chisholm Jr
A Two-Component Aggregation Model, Thomas A. Chisholm Jr
Dissertations, Theses, and Masters Projects
An aggregation model which allows specification of primary particle size, density, and fractal dimension for two different particle types was written. Three stickiness values are used, the stickiness of each particle type to itself and the stickiness between particle types. Aggregation mechanisms considered include differential settling and turbulent shear. The model is used in three forms. In its simplest form, it operates on a closed system with aggregates breaking up when their size approaches the Kolmogorov scale. If the system begins with two types of primary particles, larger aggregates have uniform composition. A second version of the model includes removal …