Earth and Planetary Sciences ETDs


Lyman Persico

Publication Date



This dissertation follows the hybrid format as defined by the University of New Mexico's Office of Graduate Studies. The three chapters were written as manuscripts to be submitted to different peer-reviewed journals. Chapter 1 is submitted to the journal Earth Surface Processes and Landforms. Chapter 2 will be submitted to the journal Climatic Change soon after this dissertation is published. Chapter 3 is already published in the journal Quaternary Research (November, 2011). Chapter 1 explores differences between historical and natural variability in fluvial systems in the Greater Yellowstone Ecosystem. I used beaver-pond and other fluvial deposits as proxy records of beaver occupation to compare historical fluvial activity to that throughout the Holocene. The Holocene record prior to Euro-American activities provides a better indication of the natural range of variability in beaver-influenced small stream systems of the GYE. Chapter 2 focuses on how stream discharge on small streams in the GYE has varied in the 20th century and also during severe drought during the Medieval Climatic Anomaly. Using the Palmer Drought Severity Index as a proxy for summer stream discharge I have concluded that many small streams in the GYE turn ephemeral during the summer months of severe drought years. Chapter 3 explores the role of rock type in hillslope soil formation and slope morphology in the Sandia Mountains of New Mexico. Resistant rock types have a profound impact on slopes by increasing the amount of coarse colluvium that traps and preserves eolian material. Accretion of eolian material along these slopes limits runoff and prevents attainment of a steady-state balance between soil production and downslope transport.

Degree Name

Earth and Planetary Sciences

Level of Degree


Department Name

Department of Earth and Planetary Sciences

First Advisor

Meyer, Grant

First Committee Member (Chair)

McFadden, Leslie

Second Committee Member

Weissmann, Gary

Third Committee Member

Coonrod, Julia




Geomorphology, Climate Change, Drought, Castor canadensis, Greater Yellowstone Ecosystem, Fluvial Systems, Soil Geomorphology, Hillslope Processes, Soil Stratigraphy, Soil Production, Sandia Mountains, New Mexico

Document Type