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In the desert southwestern United States, water resources are stressed due to anthropogenic use, drought and climate change. Arid land spring sites are considered hotspots for biodiversity, providing refugia to aquatic habitats during dry seasons. To quantify the importance of desert land springs, this research applied an interdisciplinary approach to assess 78 springs of Cibola National Forest, New Mexico. Of specific importance are several springs that provide habitats for the endangered Zuni Bluehead Sucker (ZBS), Zuni Mountains, New Mexico. Inputs to the three remaining ZBS habitats include spring waters and shallow alluvium waters from stream channels upstream from spring discharge. This research used hydrogeochemical methods to determine flow paths, mixing scenarios, residence time and recharge mechanism for ground, surface and spring waters for the ZBS habitats. Continuous monitoring of physico-chemical parameters at the three ZBS habitats lead me to propose a water quality stability classification (WQSC) that differs upstream and downstream from spring inputs: 1) high WQSC (downstream from perennial spring), 2) medium WQSC (perennial waters upstream from spring) and 3) low WQSC (stream areas that dry). Sampling of biological communities showed that biodiversity varies with and may be influenced by the WQSC. Hydrogeochemical analysis indicate that springs are from confined regional and local aquifers. Isotopologues (δ18O, δD, 3H) indicate that spring waters discharge from confined aquifers and are recharged primarily through snowmelt with a residence time greater than 70 years. In contrast, waters in the shallow alluvium are recharged from both snow and rain events. Geochemical mixing models explain seasonal inputs to ZBS habitats, where spring waters provide up to 99% of water during dry seasons. Continuous monitoring indicates that springs provide input of geochemically stable waters that maintain appropriate physico-chemical parameters (dissolved oxygen co

The timing and processes of development of the high topography and high relief of the southern Rocky Mountains of Wyoming, Colorado and New Mexico has been controversial for over a hundred years. The Mesozoic and Paleozoic rocks in the region formed a 3-4 km thick sub-horizontal stratigraphy that resided at elevations of zero to minus 4 km at the end of the Cretaceous. These units have been differentially uplifted/subsided and are presently at elevations of -10 to 4 km elevations, and have been eroded from above the core of many Precambrian basement cored uplifts exposed in > 4 km peaks. This study applies several different methodologies towards understanding the timing and relative importance of the events that uplifted and shaped the Rocky Mountains. These studies include incision studies (Chapter 1), detrital zircon analysis of Cenozoic fluvial deposits resting on the Rocky Mountain Erosion Surface (Chapter 2), and low temperature apatite fission track (AFT) and U-Th/He (AHe) low temperature thermochronology to look at differential cooling histories across the Rockies (Chapter 3). Chapter 4 investigates a project in which I designed and deployed a mobile device application for enhancing the traditional geoscience field education and research experience. Incision studies (Chapter 1) investigated the timing and rate of incision of the Black Canyon of the Gunnison by the Gunnison River. Canyon geometry is shaped by a headward-migrating knickzone presently located within the Painted Wall section of the Black Canyon. Average bedrock incision rates over the last 0.64 Ma surrounding the knickpoint vary from 150 m/Ma (downstream), to 400-550 m/Ma (within), to 90-95 m/Ma (upstream), suggesting it is a transient feature. Lava Creek B ash constrains strath terraces along a paleo-profile of the river. Within the paleo-Bostwick River tributary, we determine an incision rate of 400-550 m/Ma, reflecting incision at 2-3 times regional incision rates. We interpret this to be inci

A subsurface model was developed to characterize the influence of heterogeneity on solute phase plume migration of the Jet Fuel spill of Kirtland Air Force Base. Core –logs from KAFB boreholes were compiled, and lithology was interpolated across the study area using transition probability geostatistics (T-PROGS). High conductivity materials in the travel path resulted in a faster than average breakthrough time while, if low conductivity materials were placed in the travel path, particles were either forced to divert around the low K material, which added time and changed the direction of travel, or were forced by the hydraulic gradient to move through the materials, which also added travel time. Because these models indicate that material placement and facies dimensions significantly affect particle path, well arrival time, and breakthrough arrival time, heterogeneity should not be neglected when building groundwater models to predict movement of the KAFB Bulk Fuels Facility saturated plume.

The Mars Science Laboratory (MSL) rover is utilizing laser-induced breakdown spectroscopy (LIBS) instrumentation to determine compositions of rocks shot in Gale crater, Mars, from a distance of 1.56-7 meters. At the same time, martian breccia meteorite Northwest Africa (NWA) 7034 was analyzed with the ChemCam engineering model laboratory LIBS instrument at Los Alamos National Laboratory (LANL) at a 1.6 m standoff distance under 7 Torr CO2. Each LIBS location was pulsed with 150 shots at 3 Hz and 13.5 mJ/pulse. Comparison of NWA 7034 LIBS results with the bulk composition acquired with electron probe microanalysis (EPMA) show agreement within LIBS instrument error. Comparison of NWA 7034 data with targets from Gale shows chemical and textural similarities. This study helps bridge the gap between Mars in situ and martian meteorite data by using LIBS data to determine compositions of heterogeneous rock samples outside the compositional range previously observed on Mars.

A detailed history of drought variability in the Colorado River Basin for the last half millennium was obtained using tree ring-widths of precipitation sensitive trees as a proxy record of past climatic conditions. A one-dimensional edge detection filter was applied to standardized ring-width indices to identify years with rapid change in ring-width magnitude that may reflect changes in state. Both standardized indices and edge detection outputs were mapped to analyze how the spatial pattern of drought changes over time. A Principal Components Analysis was performed for both the mapped index and edge detection outputs to determine whether there were specific patterns within the data. This data analysis identified repeating spatial patterns between each of the identified drought periods during drought onset, with the first principal component of the edge detection accounting for 60% of the variance in the edge data. A temporal mapping of principal component loadings suggests that the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation play a significant role in forcing drought onset patterns. Superposed Epoch Analysis and a species-sensitivity analysis revealed that there are differences that exist between the droughts, including variation in the timing of the peak index year relative to the onset of drought (peak edge year), in magnitude of drought response, and in the migration patterns of drought onset, making it difficult to classify the droughts. The edge detection filter was found to be successful in identifying periods of drought onset, illustrating drought onset, and capturing migration of drought areas. The Principal Component Analysis loading patterns suggest that there are specific regions within the Colorado River Basin that vary synchronously during drought onset. Having a better understanding of these repeating regional variations in the Colorado River Basin will lead to improved drought predictability, and aid in water management in t

This dissertation details the results obtained from investigations conducted at an Aguas Buenas (300 BC-AD 800) to early Chiriquí phase (AD 900-1550) site known as El Cholo (SJ-59ECh), a mound complex located in the Upper General Valley of southern Costa Rica. Using data from surface collection along with horizontal and stratigraphic excavations, this investigation analyzed site formation and associated behavioral processes underlying the construction of a set of interconnected mounds comprising the architectural core of El Cholo. Previous research suggested that mounded sites in the Upper General area were likely seats of emergent elites with monumental constructions occupying a central position within a two-tiered settlement hierarchy. I therefore set out to identify patterns that would support or falsify this assertion, additionally proposing alternative hypotheses utilizing social models involving corporate/network dynamics and heterarchical, practice-based social processes. Evidence suggests that the mounds at El Cholo, as opposed to being residential spaces, were rather likely accretional mortuary structures, with successive funerary behavior consisting of a ceremonial mixture of interment, fire ritual and deposition of fragmented ceramic and lithic artifacts. This pattern, identified throughout the site and at different times, yielded a multi-stage occupational profile. Radiometric data suggests that activity ranged from as early as the 2nd century AD to as late as the 11th century AD. The modest nature of offerings and the diffuse and relatively uniform nature of mortuary ritual and attendant ceremonial material have implications for previous assumptions of hierarchy in the mid to late Formative in the Upper General Valley, supporting the likelihood that El Cholo may have been a manifestation of collective, corporate, heterarchically based groups rather than the result of centralized managerial processes. As such, this study re-evaluates the prevailin

Current standard geostatistical approaches to subsurface heterogeneity studies may not capture realistic facies geometries and fluid flow paths. Multiple-point statistics (MPS) has shown promise in portraying complex geometries realistically; however, realizations are limited by the reliability of the model of heterogeneity upon which MPS relies, that is the Training Image (TI). Attempting to increase realism captured in TIs, a quantitative outcrop analog-based approach utilizing terrestrial lidar and high-resolution, calibrated digital photography is combined with lithofacies analysis to produce TIs. Terrestrial lidar scans and high-resolution digital imagery were acquired of a Westwater Canyon Member, Morrison Formation outcrop in Ojito Wilderness, New Mexico, USA. The resulting point cloud was used to develop a cm scale mesh. Digital images of the outcrop were processed through a series of photogrammetric techniques to delineate different facies and sedimentary structures. The classified images were projected onto the high-resolution mesh creating a physically plausible Digital Outcrop Model (DOM), portions of which were used to build MPS TIs. The resulting MPS realization appears to capture realistic geometries of the deposit and empirically honors facies distributions.

Laser-induced breakdown spectroscopy (LIBS) is an emission spectroscopy analysis technique that continues to be developed for the study of solids, liquids and gases. Geological applications for LIBS are a particularly exciting area of research, in part due to the capabilities of the technique to quickly and simultaneously detect nearly all major, minor and trace elements on unprepared samples either in a laboratory setting or in situ. A significant advancement in LIBS research is the recent deployment of ChemCam to the surface of Mars at Gale crater onboard the Mars Science Laboratory (MSL) rover, Curiosity. ChemCam consists of a LIBS instrument and a high resolution micro-imager (RMI) and is the first extraterrestrial application for LIBS. While the state of LIBS research is rapidly developing, there are still many aspects of the techniques that warrant additional study. In this work, I have primarily focused on avenues of investigation that are most applicable to ChemCam. To encompass the range of LIBS research and applications with respect to geological materials, I have compiled a body of work that explores aspects of the fundamentals of LIBS plasma temperature as a function of distance, sample classification based on a spectral matching technique called Partial Least Square-Discriminant Analysis, and the quantification of several trace elements (Li, Rb, Sr, and Rb) using ChemCam spectra. Trace element abundances and implications for geological processes on Mars for the first 100 sols of martian rocks and soils analyzed by ChemCam are also discussed.

Much of the current literature on ancient fluvial systems is based on studies of modern rivers, but fails to differentiate between degradational and aggradational systems. That is a problem because degradational systems are not preserved and therefore are not representative of fluvial systems found in the rock record. Current research is attempting to rectify this shortcoming by exploring distributive fluvial systems (DFS) in active sedimentary basins, which have the highest likelihood of being preserved. DFS are sediment deposits that occur when rivers exit the confinement of mountain valleys and become laterally mobile in broad sedimentary basins. They are characterized by a radial pattern of channels from an apex of channel networks. The main mechanisms through which channel networks on DFS evolve are bifurcation and avulsion. Instabilities in river channels that lead to bifurcation and avulsion are related to the 1) slope of the river channel, 2) the slope of the ground perpendicular to the channel, and 3) the ratio of the slope of the floodplain or valley perpendicular to the channel-belt, relative to the down-stream or down–valley slope of the existing channel (Mackey and Bridge, 1995; Jones and Schumm, 1999; and Karssenberg and Bridge, 2008). This study sought to find a correlation between bifurcation and slope on large (>30 km) braided DFS by measuring long-profile slopes, cross-profile slopes, and slope ratios along active distributive channels. Using digital elevation models and Landsat images, a database of 1,253 long-profile slope values, 1,245 cross-profile values, and 1,112 slope ratios along 98 large DFS was compiled to gain a better understanding of slope relationships along large braided DFS and to determine if there is a correlation between bifurcation and slope. This study found a high statistically significant difference between slope ratios of non-bifurcating and bifurcating areas. Non-bifurcating areas were also found to have shallower gradient

Knowing the occurrence and distribution of soluble ionic salts allows us to model the aqueous history and geochemical conditions of surface solutions on Mars. Salts deposited as coatings are particularly important for attaining this knowledge because the thermal infrared (TIR) remote sensing method for determining mineral abundance is limited to the top few hundred micrometers of the surface. To better understand the TIR properties of salt coatings, we investigated the effects of coating thickness and texture on the TIR reflectance spectra of halite- and calcite-coated glasses. We evaluated salt coating textures that could occur on Mars: 1) continuous, uniformly thick layers of salt without exposed substrate; 2) discontinuous particulate salt coatings with variable thickness and exposed substrate. Salt-coated glasses have spectral features attributable to the substrate and the coating. Partially transmissive coatings decrease the intensity of substrate absorption bands as thickness increases. This decrease in intensity is exponential for continuous and coarse particulate (< 50 μm) halite coatings and linear for fine particulate halite coatings (< 2 μm). All halite coating textures and continuous calcite v coatings have spectral features indicating nonlinear mixing of the coating and substrate spectra. Therefore, coatings may result in significant challenges to modeling mineral abundances on Mars using a linear deconvolution algorithm for TIR spectra. An exception is fine particulate calcite coatings (< 8 μm), which are effectively optically thick and display linear spectral mixing. We find that halite coatings can cause an increase in a reflectance minimum (emissivity maximum) found previously to be useful for identifying chloride deposits on Mars. Continuous and coarse particulate halite coatings that are thicker and cover more substrate increase the reflectance minimum and are easier to detect in remotely sensed TIR spectra. Fine particulate halite does not increa

The causal mechanisms for the onset and patterns of post-Miocene erosion of the western Great Plains remain the subject of an enthusiastic debate between the roles of climatically-modulated geomorphic parameters and tectonic rock uplift as drivers of long-term erosion. This study distinguishes between these drivers on the plains of New Mexico and Colorado where post-Miocene erosion and late Cenozoic volcanism of the Jemez lineament have produced distinctive modern landscapes characterized by deep bedrock canyons and inverted, basalt-capped mesas. 40Ar/39Ar ages are used to define an episodic eruption history in the Raton-Clayton volcanic field and to quantify denudation rates from flow-capped paleosurfaces. Several datasets indicate patterns of surface topography that are consistent with dynamic rock uplift along a NE-trending flexural bulge above the Jemez low-velocity mantle anomaly, but are not well-explained by climate. They include: (1) crude volcanic "belts" of similar age, (2) retreating erosional escarpments, (3) differential landscape denudation measured from a NE-trending hinge-line of "low-to-no" erosion, (4) a NE-trending zone of broad (50-100km) convexities in stream profiles identified by an analysis of channel steepness (5) reorganization of stream networks from ESE-flowing streams, to a SSE flowing Canadian River that takes advantage of a relative base level fall in the SE, and (6) a ~150-km-long, 40Ar/39Ar-dated composite paleosurface which indicates total tilting of 64 millidegrees/Ma (and ~34 millidegrees/Ma of tectonic tilting) since 3.4 Ma. Proposed mantle-driven rock uplift along the NE-trending Jemez zone is overprinted on N-S trending mid-Tertiary uplift of the Rocky Mountain orogenic plateau relative to the Great Plains.

High precision uranium-series (U-series) geochronology provides data on timing of travertine deposition at Soda Dam, and a paleohydrologic record for the Valles Caldera hydrothermal system in Northern New Mexico for at least the last 500 ka. Travertine-depositing springs occur in San Diego Canyon, the only surface drainage outlet for the Valles Caldera, along the intersection of the Jemez fault zone (JFZ) and the Jemez River. This travertine-depositing hot spring system is part of the Valles Caldera geothermal system, which has been active throughout the Quaternary and explored for the past three decades for geothermal energy potential. New dates, compiled with previous dating, provide improved geochronologic and geologic context with respect to incision rates of the Jemez River and the episodic nature of travertine deposition. The largest volume deposit (deposit A), high in the landscape on the west side of the river, yields stratigraphic ages ranging from >500 ka (outside of U-series range) to 287 ka, and caps paleo Jemez River gravels at 132 m above the modern river. Deposit A is intruded by spar calcite dikes of 486, 455, and 339 ka that are interpreted as episodes of elevated hydrologic head in the hydrologic system generated by caldera paleolakes that were present in several unresolved intervals throughout the recent Quaternary, beginning immediately after the formation of the caldera 1.25 Ma. Intrusions also occur at 207, 211, 111 and 96 ka, during interglacial Marine Isotope Stage's (MIS) 9, 7 and 5. Deposit Ai is inset into deposit A and yields stratigraphic ages of 183 to 132 ka. Ancestral Jemez River gravels cemented by calcite rinds provide a terrace 30 m above the modern river and yield an age of 201 ka, producing a robust bedrock incision rate of 160 m/Ma for the last 200 ka. A cross-cutting calcite sill in deposit Ai yields ages of 111 and 210 ka, again suggesting locally elevated head during MIS 5 and MIS 7. Deposit B is a fissure/mound deposit on th

According to the University of New Mexico's Office of Graduate Studies, this dissertation follows a hybrid format; the chapters were written as manuscripts to be submitted to peer-reviewed journals. Chapter 1 was published in the journal Quaternary Research (May, 2011) and chapters 2 and 3 will be submitted to appropriate journals soon after this dissertation is published. Chapter 1 announces new age determinations for previously unstudied topographically-controlled eolian deposits and older ages for sand sheets than were reported by previous investigators. Chapter 2 focuses on the distribution, age, and geomorphic implications of topographically-controlled eolian deposits on Black Mesa. Chapter 3 describes the role of advanced soil profile development on the stability of eolian systems; a factor generally overlooked by researchers interested in quantifying the relative activity of sand dunes. Appendix A contains the results of tests that determine the efficacy of samples used in optically stimulated luminescence dating in all three manuscripts.

This dissertation investigates Late Intermediate Period (AD 1000-1400) hilltop settlements of the central Andean highlands. Rather than a traditional warfare-centered political perspective, the research employs primarily an ecological model in which to evaluate the widespread settlement shift to high altitude ridge tops beginning ca. AD 1000. More specifically, the research investigates the multi-faceted role that climate change may have played in the establishment of LIP hilltop settlements. I examine the concomitant shifts in the local ecology and the economic organization of hilltop communities. Using a multi-scalar and methodologically diverse research design, incorporating ethnohistory, field survey, excavation and GIS, I examine the archaeological and physical landscape around a sample of large Chanka hilltop settlements. Specifically, I adopt a settlement ecology approach in which to evaluate the individual factors which contributed to the high elevation settlement pattern. I argue that the relocation of local populations to high elevation aggregated sites was symptomatic of large scale environmental, rather than political change. More specifically, I argue that regional hilltop settlement was linked to a change in subsistence with a new emphasis on high altitude agro-pastoralism, which would have been an effective risk reduction strategy, most effectively organized from these new settlement locations. In this context, I assert that regional conflict is more accurately understood as an outcome of resource and economic stress during a time of increased aridity. On a broader scale this study makes important contributions towards a growing scholarship concerning how prehistoric populations responded and survived in the face of a multitude of co-occurring crises, including political instability, economic stress and climate change.

In northeastern Arizona, on the Colorado Plateau, landscapes associated with weakly cemented sandstones are sensitive to Holocene climate changes on millennial to decadal scales. It is hypothesized that these climate changes affect processes of weathering, erosion and plant community establishment on hillslopes in this semiarid environment. In small basins formed at the base of Black Mesa escarpment west of Chinle, Arizona, Jurassic sandstones cemented mainly by clay minerals weather by hydration, favoring relatively high erodibility. Two end member slope forms related to aspect-induced topoclimates are present in this area: (1) transport-limited slopes mantled by 10-20 cm of weathered materials and (2) bedrock slopes lacking accumulations of weathered materials. In addition to being ideal end-members of a continuous hillslope morphology series, these two slope types and their associated plant communities can be considered end-member ecological systems. The zone of transition, or ecotone, between them represents a gradational change that, due to the slope form-aspect relations, may have shifted spatially during the late Holocene. We identified two sub basins that encompass the full range of aspects and analyzed the hillslopes by characterizing vegetation, measuring soil thicknesses and estimating erosion rates. In contrast to south-facing, more xeric slopes, north-facing, more mesic slopes have substantially thicker mantles, less exposed bedrock and the greatest tree and herbaceous cover. On the more transitional aspects, there is an intermediate amount of vegetation and bare bedrock cover and intermediate soil thicknesses compared to the aspect-related end member slope forms. Hillslope erosion rates vary by slope aspect and slope position. The soil geomorphic and dendrogeomorphic data indicate that, through feedback mechanisms linking weathering, erosion and vegetative growth, the hillslope transition zones are responding dynamically to late Holocene climate change

Closed basin lakes provide important data on paleo- and modern environmental conditions because of their sensitivity to climate variability, particularly variations in precipitation. In arid and semi-arid regions throughout the world, playas play an important role in biological communities, agriculture, and as a major dust source when they are dry. The ability to monitor these lakes at a high temporal resolution is critical to understanding their response to climate variability as well as improving our interpretation of their paleoenvironmental record, yet such monitoring is currently conducted on few playas. There are several challenges to effectively monitoring playa systems, but the integrated use of Landsat and MODIS sensors allows a simple, reliable way to monitor rapidly changing playa lake inundation. This study produced long-term, high spatial resolution datasets as well as high temporal resolution datasets of playa lake inundation areas. The use of a single threshold and a single spectral band for each sensor provides the basis for continual and automatic monitoring of small, rapidly changing water bodies in arid regions. A dataset of this extent has not been compiled for a playa system like the pluvial Lake Palomas (PLP) playas. In addition, this study uses the inundation areas time series produced by the multi-scale remote sensing methodology to quantify previously unknown parameters of playa inundation in the PLP basin including the duration, peak area, seasonality and interannual variability of playa lake inundation. The location of sub-basins within the PLP basin and the geographic distribution of summer and winter precipitation cause distinct flooding patterns in individual playas. Effective precipitation must reach a specific threshold before inundation area can increase. High intensity precipitation that currently occurs primarily during the summer is required for initial inundation, and cool-season precipitation helps maintain lake areas during dri

Here we summarize all current knowledge about the Maria Fold and Thrust Belt and McCoy Basin tectonic provinces of southeastern California. We also present new geologic mapping, structural analysis from macroscopic to microscopic scale, U-Pb zircon ages and Ar-Ar hornblende and biotite ages from key areas in the Maria Fold and Thrust Belt and McCoy Basin to resolve kinematics and timing of polyphase deformation events related to the Mesozoic Cordilleran Orogeny in southeastern California. The Maria Fold and Thrust Belt (MFTB) is an east-west trending belt of amphibolite grade metamorphic rocks characterized by largely south-vergent folds and ductile shear zones that place Jurassic and Proterozoic crystalline rocks over Paleozoic and Mesozoic sedimentary and volcanic rocks correlative to strata observed on the Colorado Plateau and in southeastern Arizona. Rocks in the MFTB have undergone polyphase ductile deformation and high grade metamorphism. The McCoy Basin trends subparallel with the MFTB and is defined by exposures of Jurassic-Cretaceous McCoy Mountains Formation, a > 7 km thick siliciclastic wedge of sandstone, siltstone and conglomerate. In contrast with the MFTB, rocks in the McCoy Basin have undergone primarily brittle deformation and have undergone low grade regional metamorphism. Important questions remain regarding the tectonic evolution of these two tectonic provinces, the relationship of these two provinces to each other and their relationship to the Cordillera at large. Resolving kinematics and timing of polyphase deformation in the MFTB and assessing synorogenic response in the McCoy Basin using established and new methods of structural geology and geochronology will resolve these questions and illuminate fundamental geologic processes related to orogenesis. This dissertation is divided into three chapters, with the goal of assessing kinematics and timing of deformation in the MFTB and McCoy Basin. A general encompassing hypothesis for investigations