Author
Agenbroad, Brian PeterIssue Date
2019Advisor
Rasmussen, Craig
Metadata
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The University of Arizona.Rights
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author.Abstract
The accumulation of pedogenic carbonates is important to understanding carbon cycling, to include carbon sequestration, in arid and semi-arid regions. Carbonate accumulation in southern Arizona displays significant spatial variation, particularly in alluvial deposits that dominate basins in the region. Improved understanding of the controls on pedogenic carbonate accumulation is needed. Here it is hypothesized that carbonate accumulation in alluvial fans is controlled significantly by parent material composition. To address this hypothesis, samples were taken from a chronosequence consisting of multiple buried horizons and carbonate accumulations. Parent materials include calcareous and non-calcareous meta-sedimentary rocks, diabase, granites and schist. Measurements included carbonate concentration using a traditional method of hydrochloric acid digestion. This was compared to results generated with an infrared spectral curves for calcium carbonate concentration. Bulk elemental content was obtained via X-ray fluorescence analysis for quantification of immobile element accumulation. Pedogenic iron contents extracted by both sodium dithionite and ammonium oxalate, were taken as indicators for changes in weathering. Results indicate that a mix of eolian material and calcareous rocks are the dominant sources of carbonate accumulations.Type
textElectronic Thesis
Degree Name
M.S.Degree Level
mastersDegree Program
Graduate CollegeSoil, Water and Environmental Science