Parent Material Contribution to Jemez River Basin, NM Soils Using Quantitative XRD and XRF.

The Jemez River Basin lies within the Valles Caldera National Preserve in New Mexico.  The geology of this area includes examples of rhyolite, pumice, and tuffs with some zeolitized rock units. Soils in the Jemez River Basin are part of the critical zone which extends from vegetation heights down to the groundwater depths.  Recently, this area was established as part of the University of Arizona led Jemez River Basin-Santa Catalina Mountains Critical Zone Observatory.  In order to better understand soil development and processes in the basin, soil and parent material samples were collected and analyzed for mineralogy and chemistry.  In order to determine the contribution of individual parent material types to soil sample mineralogy, rock samples were used as standards within quantitative mineralogical software (Rockjock; Eberl, 2007).    Rock and soil samples were analyzed for mineralogy using x-ray diffraction.  Rock mineralogy was quantitatively determined using a combination of Rockjock (Eberl, 2007) and Rietveld analysis.  X-ray fluorescence analysis of both rock and soil samples provided elemental compositions.  Quantitative elemental ratios were then used to constrain and/or confirm the quantitative mineralogy results.