FROM NEVADA SOILS TO TENNESSEE DEPRESSIONS: INVESTIGATING FEATURES AT VARIOUS SCALES

The results of two projects, one conducted on petrocalcic soils in Nevada and one on curious depressions on the Cumberland Plateau of Tennessee will be presented. Other ongoing research projects may be discussed if time allows. First discussed will be research on the development of the Mormon Mesa and related soils in Nevada. Understanding the development of petrocalcic soil horizons is important because they are understudied and hold a record of past climate and geomorphic change since their formation. Micro- and macromorphic examination of the mineralogy and morphological features of petrocalcic horizons near Mormon Mesa, reveals detrital carbonate clasts that are selectively dissolved in the pedogenic carbonate matrix. Recognition that this occurs is significant because selective removal of clasts in these materials could cause misinterpretation of detrital clast provenance if preserved in the geologic record. The second research project that will be discussed is an investigation into large depressions in thick sandstones atop the Cumberland plateau in Tennessee. Geomorphic descriptions along with geophysical techniques including seismic refraction tomography, electrical resistivity tomography, and multi-channel analysis of surface waves were used to test an over 70-year-old hypothesis regarding the collapse origin for these features. Evidence was found to support their collapse origin and future work is planned to determine the development of their current shape and relationship to underlying structures on the plateau.