Browsing by Subject "Arizona"

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Arizona, A. elegans
(Society for the Study of Amphibians and Reptiles, 1976) Dixon, James R.; Fleet, Robert R.; Wilson, Larry David
Arizona’s Rising STEM Occupational Demands and Declining Participation in the Scientific Workforce: An Examination of Attitudes among African Americans toward STEM College Majors and Careers
(Texas Education Review, 2017) Jackson, Jerlando F. L.; Charleston, LaVar J.; Lewis, Chance W.; Gilbert, Juan E.; Parrish, Walter P. III
According to the Bureau of Labor Statistics (2008), science, technology, engineering, and math (STEM) occupations constitute a growing sector of Arizona’s economy. However, the number of African Americans earning degrees related to these occupations has not kept pace with this growth. Increasing the participation of African Americans in STEM education fields and subsequent related occupations in Arizona is vital to growing and maintaining the state’s economic stature. This objective is made even more compelling given that each year, from 2008– 2018, there are 3,671 projected job openings in STEM fields in Arizona. This study explores the extent to which the attitudes held by African Americans in Arizona toward STEM related majors and careers influence their likelihood of joining the state’s scientific workforce. Our analyses reveal the importance of career consideration, confidence in one’s ability to be successful in a STEM related field, and family support of the pursuit of STEM education and careers.
El Choque de Arizona con los Derechos Humanos: la Ley SB 1070
(2011) Gilman, Denise
Este artículo analiza la legislación antiinmigrante adoptada en Arizona, Estados Unidos, conocida como la Ley SB 1070, desde la perspectiva de los derechos humanos. Describe el impacto sumamente negativo que tiene la ley sobre los individuos que afecta. Al mismo tiempo considera la xenofobia que la motivó y el ambiente discriminatorio que trae como consecuencia en contra de las minorías étnicas y raciales, particularmente los latinos. Al hacerlo, pone en duda la efectividad de la Ley SB 1070, y otras medidas represivas, para controlar la migración irregular. Procede a analizar las violaciones graves de derechos humanos que implica la ley, en relación con el derecho a la igualdad y la libertad y la obligación general de un Estado de promover un ambiente respetuoso de los derechos humanos, especialmente para personas tradicionalmente marginalizadas, como son los inmigrantes irregulares. El artículo concluye con un análisis de la ambivalencia imperante en Estados Unidos hacia el uso de los derechos humanos como marco para cuestionar la Ley SB 1070 y medidas similares. El artículo llama a la mayor utilización del derecho internacional de los derechos humanos como herramienta para impulsar cambios en la política y legislación de los Estados Unidos en materia migratoria.
Estimation of Gas Permeabilities for the Maricopa Site, Arizona
(1998) Scanlon, Bridget R.; Angle, Edward S.; Liang, Jinhuo
Upward and downward migration of gases from waste-disposal facilities is a critical issue for low-level radioactive waste disposal. Gaseous radionuclides in low-level waste include H-3, C-14, and Rn-222. Upward migration of gases to the surface can be important, particularly during operation of the facility (Kozak and Olague, 1994). High tritium values (for example 1,100 TU at 24 m depth, 162 TU at 109 m depth) have been found adjacent to the Beatty site, Nevada, that cannot readily be explained by liquid or combined liquid and vapor transport (Prudic and Striegl, 1995; Striegl et al., 1996). Because disposal practices at Beatty varied in the past and included disposal of as much as 2,000 m3 of liquid waste, further research in tritium movement at Beatty is warranted. Transport mechanisms for gases include not only diffusion but also advection. Analysis of gas transport is important at many low-level waste disposal facilities as shown by the intensive program to monitor concentrations and concentration gradients of gaseous radionuclides proposed for the California low-level radioactive waste disposal facility (Harding Lawson & Assoc., 1991). Performance assessment calculations require information on parameters related to gas transport to predict long-term migration of gases in the subsurface. The purpose of this study is to evaluate different techniques of estimating gas transport parameters and monitoring subsurface gas migration. The objective of this study is to examine different techniques for evaluating gas permeability. Pneumatic pressure tests will be conducted to estimate vertical and horizontal air permeabilities at different levels. In addition, permeabilities will be calculated from atmospheric breathing data that will include evaluation of subsurface response to barometric pressure fluctuations. Computer simulations suggest that air from the surface can move several meters into the ground during typical barometric pressure cycles (Massmann and Farrier, 1992). Gas ports will be installed at different depths in two boreholes to evaluate atmospheric pumping. The results of this study will provide valuable information on subsurface gas transport processes and the various techniques to obtain data on parameters required for simulation of such processes. These data will be required for performance assessment calculations.
Evaluation of the Razorback Sucker (Xyrauchen texanus) and Colorado Squawfish (Ptychocheilus lucius) reintroduction programs in central Arizona based on surveys of fish populations in the Salt and Verde rivers from 1986 to 1990
(Nongame and Endangered Wildlife Program, Arizona Game and Fish Department, Phoenix, Arizona, USA, 1993-09) Hendrickson, Dean A.
Between 1981 and 1990, more than 11 million hatchery-produced razorback suckers (Xyrauchen texanus) and 750,000 Colorado squawfish (Ptychocheilus lucius) were stocked to historic ranges in the Verde and Salt rivers in Arizona, where natural populations had been extirpated. Efforts to date have focused on broad-scale stockings and general fish surveys to evaluate success. Only 519 razorbacks and 444 squawfish were taken in several years of intensive electrofishing and netting surveys during all seasons throughout large segments of both rivers. Survival of razorbacks appears better in the upper Verde River than in the Salt River, while squawfish appear to fare better in the Salt River than do razorbacks. Most recaptures of either species were taken within weeks of stockings; relatively few individuals were verified to have lived more than a few months in the wild. Large populations of razor backs have not established in mainstreams, although groups have persisted in small, isolated, peripheral habitats where emigration is blocked or impeded. Despite growth to maturity of at least some razorbacks, no evidence of wild reproduction was found. The few squawfish known to have over-wintered in the wild were also taken from a habitat closed to downstream emigration. Proximate impediments to large-scale successful recruitment of stocked individuals to wild populations clearly include predation, principally by exotic flathead catfish and smallmouth bass, and coincident inability of hatcheries to produce large numbers of individuals for release at sizes large enough to escape predation. Despite limited success, it is recommended that stockings of both species continue for two reasons. Large-scale field experiments easily accomplished under the "experimental, non-essential" designation with readily available hatchery fish can elucidate mechanisms of recruitment failure for hatchery stock. These should emphasize experimental analyses of factors affecting mortality, movements and habitat use of stocked fish. Effects of fish condition, transport and stocking stress, size, stocking season, and parasites are other variables which need research. Along with experiments, continued stockings, especially in the case of razorbacks, even with low recruitment rates, appear very likely to contribute to establishment of long-lived populations, and are therefore recommended for both species. Stockings should be as extensive as possible, and focus on releases to closed, peripheral riverine and reservoir habitats (e .g. isolated backwaters), preferably with low or reduced predator populations. While direct stocking of larger individuals would likely increase survival rates in the wild, absolute numbers stocked would remain small given existing facilities . Stockings of far greater numbers of small individuals to such isolated, "wild" habitats and subsequent "wild" growth there prior to release, via either natural or artificial mechanisms, to larger, adjoining habitats, will likely prove to be the most economical and successful approach to establishing multiple, new populations oflong-lived individuals. Recommendations for immediate habitat management actions for both species include manipulations of predator populations and maximization of availability of backwater habitats. A broad-scale, annual field monitoring effort should continue, but most importantly the program should shift to emphasize experimental research. Effectiveness of the reintroduction program could be greatly improved by high-level administrative adjustments with particular attention to development of program objectives, coordination among production, research and monitoring components and frequent evaluation of progress toward objectives.
Field and petrographic analysis of mylonitic fabrics : implications for tectonic corrugation development, Tanque Verde Ridge, Arizona, USA
(2005-12-24) Perry, Ethan R.; Mosher, Sharon, 1951-
Tanque Verde Ridge (TVR) in Saguaro National Park, Arizona, USA, represents a large-scale lineation-parallel ridge (tectonic corrugation) within the Santa Catalina-Rincon Core Complex. Field and petrographic features record a history of lineation-parallel extension and boudinage occurring across a ductile to brittle deformational continuum during core complex exhumation. Lineation-perpendicular ductile to brittle features suggest the importance of extension orthogonal to lineations during exhumation and need to be factored into the debate on tectonic corrugation evolution. TVR is a foliation-defined antiformal flexure, concordantly bounded at the toe by a brittle detachment fault system. The footwall mylonite is strongly foliated (suggestive of flattening, rather than constriction) and lineated (WSW-trending). Ductile, micro- (thin section) to macro- (hundreds of meters) scale features are oriented both lineation-parallel (e.g., S-C' fabrics, asymmetric porphyroclasts, shear zones) and perpendicular (e.g., shear zones, asymmetric quartz fabrics). These features record dominantly WSW, and secondarily NNW and SSE, directed non-coaxial shear, respectively. Across the corrugation, foliation flexures exhibit both lineation-parallel and perpendicular fold axes. Distended necks of micro- to meso-scale boudins contain NNW-SSE striking zones of intense brittle fracturing, brecciation and cataclasis. The ductile, mylonitic foliation is passively affected across these boudin neck zones as foliation dip varies from sub-horizontal to >45°. This suggests a temporal link between mylonite formation, extension-related deformation and the development of the corrugated surface. Oriented thin sections and field observations from across TVR and across outcrop-scale corrugation-like features constrain the conditions during mylonite development to lower-amphibolite facies and the spatial relationship of micro- to meso-structural features across the corrugation. On the basis of field and petrographic evidence, a new model for the evolution of tectonic corrugations is proposed, whereby original anastamozing shear zones within the deep-seated, ductile shear zone are amplified in response to bidirectional extension (including boudinage, and spatially related brittle fracturing). Shear zone modification is progressive and is synchronous with non-coaxial simple shear. Overall flattening of the shear zone is predicted in response to this extension. Notably, mylonitic fabrics at TVR do not record a history of large-scale constrictional deformation. Tectonic corrugations can initiate at depth as a result of original shear zone morphologies, be modified by boudinage during bidirectional extension, and be translated up-dip during progressive core complex exhumation. Corrugations are manifestations of deep-seated, multi-scale processes that influence shear zone dynamics during large-scale crustal extension.
Final Project report - Interim progress report on a study of the utility of data obtainable from otoliths to management of Humpback Chub (Gila cypha) in the Grand Canyon
(1997-06-13) Hendrickson, Dean A.
This study was initiated with the objective of studying various aspects of the physical and chemical structure of otoliths of humpback chub from the Grand Canyon of Arizona, and primarily from the Little Colorado River (LCR). These studies were to shed light on the utility of otolith studies for improving knowledge of the life history of this endangered species, and to evaluate the potential application of these techniques to questions posed by resource managers. Whole fish specimens, skeletons, or preserved heads of specimens were provided to the author by a diversity of Arizona Game and Fish field crews who collected from 1989 through 1993. The author, with assistance of Dr. Ed Brothers, extracted, prepared and examined otoliths. Data analysis and reporting was the sole responsibility of the author. Specifically, the study was to obtain age estimates (years of age) from otoliths of 50 selected skeletonized adult specimens of Gila cypha collected from the Grand Canyon by Arizona Game and Fish Department in 1989 and 1990. It was also to obtain age estimates (days of age) for 100 selected young-of-the-year (y.o.y.) Gila cypha collected during the same and subsequent years. Age estimates for y.o.y. were predicated on the assumption that increments counted in the otoliths were deposited daily, and that increment counts could thus be translated to days of life since the date of first increment formation (generally within the first few days following spawning). Since that hypothesis had not been specifically tested in this species, the study also was to test the hypothesis that increments form on a daily basis, both in the field and in hatchery experiments. Since at least some humpback chub appear to move across a typically strong thermal gradient at the interface of mainstem Colorado River (MCR) waters and the discharge of the LCR, which is generally much warmer than MCR, it was hypothesized that this transition might lead to the formation of marks, both physical and chemical, in otoliths and that these marks might be used to reconstruct individual life histories with respect to timing of this inter-river movement. Though studies conducted since initiation of the present study {9017} have recently made significant contributions toward documentation of movements of adult humpback chub in the mainstem Colorado, still very little is known of movements of y.o.y. It had been hypothesized that if swept out of the LCR into the mainstem Colorado, the transition might be lethal or have other deleterious impacts on y.o.y. survival and growth. A mark in otoliths that unambiguously conveyed information about extent and timing of movements across this inter-river interface, could thus be valuable in furthering understanding of population dynamics and movements. It was thus proposed to search for such marks in otoliths and to conduct experiments to study the effects of temperature changes on otolith structure. The original study design also called for an analysis of the feasibility of determining annual growth period duration from otoliths of post young-of-the-year individuals of Gila cypha for all growth periods throughout the life of specimens. At the time of study design, there was considerable discussion and application of chemical analyses of otoliths in the literature of fishery management and stock identification. Studies at this time indicated considerable promise for the techniques, and likely applicability to reconstruction of detailed individual life histories of humpback chub. It was hypothesized that individuals that moved across the MCR-LCR temperature and water quality gradient would deposit a chemical/structural signal in their otoliths that reflected this transtion from one river to the other. Since the temporal structure of otolith deposition and specimen birth date could be recovered from the otoliths as well, the absolute date of the movement event, and fish size at the time, might be accurately recoverable as well. It was therefore proposed to carry out analyses of micro-spatial (=chronological) variation in elemental composition in otoliths of 20 selected individual Gila cypha specimens from the Grand Canyon for evaluation of the utility of such techniques for reconstruction of movement history of individuals. In addition it was hoped to compare total elemental composition among otoliths of 5 selected individual specimens of young-of-the-year Gila cypha captured in the Little Colorado River, otoliths of 5 hatchery-reared young-of-the-year Gila cypha, and otoliths of 5 selected Gila cypha suspected or known to have moved between the Little Colorado River and mainstem Colorado River in the Grand Canyon as a means of investigating the effect of these diverse environments on otolith composition. An accidental spill of isotopes into the LCR drainage {9018} was thought to potentially provide isotopic signatures in otoliths. If some of the isotopes characteristic of the spill were found in otoliths, their presence might serve as an unambiguous marker indicating time spent in the LCR. It was therefore proposed to determine the isotopic composition of a subsamplc of the same (or comparable) specimens used for microchemical composition studies. Since otolith isotopic composition had been indicated in other studies tu he highly correlated with ambient temperature, isotopic compositional changes during the temporal sequence of otolith deposition thus might also reflect inter-river transitions. Specimens from experiments designed to determine the effects of ambient temperature on otolith increment deposition were therefore to be examined for isotopic composition as well in an attempt to better understand the effect of temperature on isotopic composition of otoliths. In the course of these studies a bibliography of literature relevant to methods and problems of estimating age and growth of Gila cypha and chemical composition of otoliths as related to application of otolith chemistry to reconstruction of the environmental history of individuals was compiled and is provided with this report. Though this bibliography can hardly be claimed to he comprehensive since the literature in this field has become very extensive, it should serve as a starting point for future researchers interested in otolith studies. Finally, the appendices of this report provide an inventory of all specimens of Gila cypha from the Grand Canyon used (and not used) in this study, and the earlier interim report on early results from this study (less the bibliography, which has been updated in this report). Some questions answered in that report, such as comparisons of ageing techniques using the asteriscus and opercle, are not reiterated here, and the figures provided there amply illustrate all otolith structural features and variations discussed in this report.
Geographic variation in morphology of Agosia chrysogaster, a Sonoran desert cyprinid fish
(Arizona State Univeristy, Tempe, AZ, 1987-05) Hendrickson, Dean A.
Morphometric analyses of Agosia chrysogaster (Girard) indicated a northern morph native to Bill Williams, Gila, Sonoyta and de la Concepcion basins of Arizona, New Mexico and Sonora, and a southern form from Willcox Playa of Arizona and Rios Sonora, Yaqui, Mayo, Fuerte and Sinaloa of Sonora and Sinaloa, Mexico. The latter is smaller, and less sexually dimorphic, but has longer pre- and postdorsal body lengths. Populations in the geographically intermediate Rios Sonoyta and Sonora are morphologically intermediate. Males differ more between morphs than do females. Meristic characters show considerable overlap between morphs, but the northern form has higher mean lateral line scale counts. Highly tuberculate nuptial males, characteristic of the northern morph, were not found in the south, nor were "spawning" pits characteristic of breeding activities of the former. Morphs differ on a multivariate axis on which temporal variation at single localities is also reflected. Distances among some intra-locality samples on this axis were greater than least inter-morph morphological distances. Measures of morphological dissimilarity were weakly correlated with inter-sample differences in elevation, latitude, and longitude, but more highly correlated with an index of hydrologic isolation among localities. Differentiation among basins thus appears to reflect hydrographic isolation, rather than ecological conditions. Electrophoretic data on A. chrysogaster produced relationships patterns largely incongruent with results of the morphological analyses, and with unexpected geographic area relationships.
Geothermochronometric and stratigraphic constraints on the structural and thermal evolution of low-angle normal fault systems : case studies from southwestern Nevada and west-central Arizona
(2016-12) Prior, Michael Gordon; Stockli, Daniel F.; Behr, Whitney M; Ketcham, Richard A; Spencer, Jon E; Wells, Michael L
The structural evolution of low-angle normal faults (detachment faults) has been an extensively debated topic since the initial recognition of these structures throughout the western U.S. Cordillera and their subsequent identification within extensional provinces across the globe. An improved understanding of how detachment faulting occurred at a variety of scales within continental extensional provinces can help refine structural models of how complex detachment fault systems evolved during progressive extensional deformation. This dissertation addresses the evolution of detachment fault systems using a thermochronometric approach that is coupled to hanging wall stratigraphic data in order to evaluate how the thermal history along detachment faults can evolution inform our understanding of the spatial, geometric, and temporal evolution of these fundamental extensional structures. Evaluating the accuracy of thermochronometrically-derived fault slip rates within large magnitude extensional systems has important implications for slip rate interpretations that can be significantly affected by various structural complexities within the footwall and hanging wall. Three new and distinct case studies are presented in order to understand the temporal and spatial development of low-angle normal fault systems and the resulting metamorphic core complexes that have developed within varied extensional settings. Chapter 1 utilizes (U-Th)/He thermochronometry to understand the significance of small-scale (100’s to 1000 m scale) fault blocks within the Bullfrog Hills-Bare Mountain detachment fault system that accommodated transtensional deformation within the southern Walker Lane in southwestern Nevada. The timing of Miocene extensional exhumation was determined in the Bullfrog Hills and Bare Mountain Nevada as well as the effects of several main detachment faults, faults with multiple segments, small scale incisement and excisement detachment faults, and preexisting contractional structures on detachment fault evolution and the interpretation of thermochronometric data from within detachment fault domains. Chapter 2 focused on evaluating the larger scale (km to 10’s of km) structural evolution of progressive detachment fault breakaways that developed along the Buckskin-Rawhide detachment fault system during large-magnitude (~40-50 km) Miocene displacement in the lower Colorado River extensional corridor of west-central Arizona. By coupling geothermochronometry data from within the pre-and synextensional sedimentary record preserved within the Lincoln Ranch hanging-wall basin, this study constrains the timing of a tertiary detachment fault breakaway and provides new insights on the timing of subaerial footwall exposure. Chapter 3 applies a high-density sampling strategy along an ~55 km long, slip-parallel transect within the Harquahala Mountains of west-central Arizona, one of the lesser studied examples of a classic Cordilleran metamorphic core complex in the lower Colorado River extensional corridor. Apatite and zircon (U-Th)/He ages throughout the Eagle Eye detachment fault footwall are combined with geothermochronometry data from sedimentary and basaltic hanging-wall rocks in order to determine the inception and duration of extension, fault displacement magnitude, fault slip rates, fault geometry, and timing of subaerial footwall exposure along the Eagle Eye detachment fault. New results are used to evaluate the structural evolution of the regionally correlative lower Colorado River extensional corridor detachment fault system at the southern extent of the Whipple tilt domain, which has important implications for the coherent behavior of regionally extensive continental detachment fault systems.
Interim progress report on a study of the utility of data obtainable from otoliths to management of Humpback Chub (Gila cypha) in the Grand Canyon
(1993-02-05) Hendrickson, Dean A.
Daily growth increments of otoliths of fishes have been useful in many fishery applications since they have been demonstrated to provide a precise method of ageing individuals and reconstructing individual growth and, possibly, movement or habitat histories. These techniques have not been previously applied to humpback chub, but are believed to have considerable potential for providing knowledge of this difficult to sample and little-understood species. Large temperature and water quality gradients apparently traversed by individuals of this species in the Grand Canyon are of a magnitude likely to produce structural and/or chemical signals in the crystalline calcareous otoliths. If so, since otoliths grow by accretion of daily increments (much like trees develop yearly growth rings), and are stable structures, which unlike scales, are not susceptible to reabsorption except in the most extreme conditions, they retain a structural and chemical chronology of habitats occupied. If the relationships of ambient physical and chemical conditions to otolith structure and composition can be described, a chronology of habitat occupancy and growth for individuals could theoretically be reconstructed with daily precision. Such reconstructions of growth rates, birth dates, movement histories, and possibly, birth place (based on chemistry at otolith formation or during early life), could provide extremely valuable life-history information regarding timing of spawning, cohort recruitment, mortality rates, and data on other population parameters critical for management of this endangered species. The feasibility of using otoliths and opercles of humpback chub for age estimation of individuals has been preliminarily investigated by examining otoliths and opercles from a total of 47 juvenile (ages 0 through 1 +)and 43 adult (estimated ages 2- 23) specimens collected in the Little Colorado River (71 specimens) and mainstream Colorado River (19 specimens) at various places in the Grand Canyon between 1988 and 1992. Studies are continuing, and at this point, due to both sample size and numerous other limitations, and ongoing refinements of techniques, conclusions made here are highly preliminary. Structures prepared and examined included opercles of 35 specimens, one asteriscus from each of 47 specimens and a lapillus from each of 56 specimens. Seventeen specimens were evaluated using all three calcareous structures (lapillus, asteriscus and opercle). The sagitta was also examined, but found to be unsuitable for ageing purposes due to its long, delicate form and irregular increments after the larval/juvenile stage. Additional lapilli have been removed from other available specimens, and a complete inventory of specimens available for further study of calcified structures is provided. Studies of micro-spatial variation in chemical composition of selected lapilli is in progress, using the highly accurate proton probe at the Institute of Geological and Nuclear Sciences in Lower Hutt, New Zealand. This method of analysis shows great promise of overcoming what has been indicated in recent literature to be significant inaccuracies of other techniques (Energy Dispersive X-ray diffraction and Wave Length dispersive X-ray diffraction) used in many of the published studies of microspatial elemental analysis of otoliths.
Katy Murdza Interview
(2023-06-06) Institute for Diversity & Civic Life; Department of Religious Studies
This interview is with Katy Murdza, the Texas regional organizer for the Immigrant Legal Resource Center, in Houston, TX. Katy describes her start in immigration activism during college, her work at a detention center through the Dilley Pro Bono Project, and her work with SA Stand Coalition and Houston Leads. She compares life in the places she has lived and also recalls her travels, including being in the Peace Corps in Panama. Katy describes the connections between the causes she organizes for and believes in, such as immigration reform, abolition, and transit.
Landscape preservation and biodiversity planning : the Kino Heritage Fruit Trees Project and beyond
(2014-05) Yaquinto, Robert Giacomo; Holleran, Michael
This report argues that historic landscape preservation efforts need to embrace biodiversity planning. Historic landscape preservation sites need to develop biodiversity plans because they are uniquely qualified to provide the continuous monitoring that successful biodiversity planning requires. Not only will biodiversity monitoring at various historic landscape sites contribute to a nationwide collection of biodiversity planning data, but it will also provide a rich source of information that can be presented to draw a wider audience into the biodiversity discussion. After considering three precedents: Old Sturbridge Village, Old World Wisconsin, and Tucson Botanical Gardens, the report focuses on the Kino Heritage Fruit Trees Project and its real and potential impacts on biodiversity planning in southern Arizona and more broadly. Finally, the report considers how seed libraries and seed swaps might serve a similar purpose in other parts of the country.
Letter to David Nicol from H.B. Stenzel on 1945-02-27
(1945-02-27) Stenzel, H.B.
Letter to H.B. Stenzel from C.E. Needham on 1939-08-01
(1939-08-01) Needham, C.E.
Letter to Kenneth E. Caster from H.B. Stenzel on 1944-11-14
(1944-11-14) Stenzel, Henryk B.
Observations on the osteology of scutellosaurus lawleri Colbert, 1981 (Ornithischia: Thyreophora) on the basis on new specimens from the Lower Jurassic Kayenta Formation of Arizona
(2016-05) Breeden, Benjamin Thomas, III; Rowe, Timothy, 1953-; Bell, Christopher J; Martindale, Rowan C
Scutellosaurus lawleri is a basal thyreophoran dinosaur from the Lower Jurassic Kayenta Formation, and it is the most abundantly known ornithischian dinosaur from the Lower Jurassic of North America. Despite its abundance in the fossil record, certain aspects of its anatomy have remained poorly understood due to the incomplete nature of the holotype, paratype, and referred specimens. I report here nearly 30 new specimens of Scutellosaurus lawleri collected along the Adeii Eechii Cliffs of northern Arizona between 1997 and 2000 by field parties from The University of Texas at Austin. Among this new material are two disarticulated associated skeletons, each preserving anatomy that is poorly known or not previously reported for the taxon, including the nasal, maxilla, lacrimal, postorbital, quadratojugal, squamosal, opisthotic, scapula, and ilium. These specimens have both been compressed taphonomically, making their removal from the surrounding matrix in their field jackets difficult without risk of damage to the fossil bone, so the specimens were CT scanned to aid with preparation. A phylogenetic analysis supports the position of Scutellosaurus lawleri as the basalmost member of Thyreophora. New autapomorphies identified include six premaxillary teeth, narrow and elongate frontals, a humerus substantially longer than the scapula, and neural spines of the proximal caudal vertebrae that are greater than 50% taller than the centra.
The osteology of Sarahsaurus aurifontanalis and geochemical observations of the dinosaurs from the type quarry of Sarahsaurus (Kayenta Formation), Coconino County, Arizona
(2013-05) Marsh, Adam Douglas; Rowe, Timothy, 1953-
Sarahsaurus aurifontanalis is the most recent sauropodomorph dinosaur to be discovered and named from the Early Jurassic of North America. The dinosaur is represented by a mostly complete and articulated holotype specimen that preserves a unique manual phalangeal count of 2-3-4-2-2 and accessory pubic foramen adjacent to the obturator foramen. The holotype of Sarahsaurus comprises a braincase and isolated cranial elements, but the skull previously referred to this taxon, MCZ 8893, can only be provisionally referred to Sarahsaurus until additional crania are found associated with postcranial material. Sarahsaurus comes from the middle third of the Kayenta Formation, which is considered to be Early Jurassic in age despite the absence of a radiometric date from that unit. A new technique used to obtain a U-Pb radiometric date from the type quarry of Sarahsaurus in the Kayenta Formation was influenced by secondary uranium enrichment in the open system of the fossil bone. That suggests that uranium within the Kayenta Formation may be the result of the movement of groundwater during the Laramide orogeny in the Late Cretaceous and Early Eocene, and lends support to the hypothesis that the uplift of the Colorado Plateau began relatively early in Late Cretaceous to the Eocene.
Postsecondary Achievement of Deaf People in Arizona: 2017
(2017) Garberoglio, Carrie Lou; Cawthon, Stephanie; Sales, Adam
Reactivation of fractures as discrete shear zones from fluid enhanced reaction softening, Harquahala metamorphic core complex, west-central Arizona
(2014-05) Pollard, Brittney Maryah; Mosher, Sharon, 1951-
Discrete (mm- to m-scale) mylonitic shear zones in the northeastern Harquahala metamorphic core complex, Arizona, show evidence of fluid-mineral interactions catalyzing deformation and metamorphism. Many contain a deformed central epidote vein with adjacent bleached haloes and flanking paired shear zones that indicate significant fluid-rock interaction during deformation. An integration of structural and geochemical methods was employed to understand timing, metamorphic conditions, and physiochemical processes responsible for producing the discrete shear zones. Field and microstructural evidence suggest the zones initiated on antecedent fractures. Electron backscatter diffraction (EBSD) analyses show a significant coaxial contribution to the shear, and quartz deformation predominately by prism slip, along with some rhomb slip, suggesting amphibolite-facies conditions during shearing. Fourier Transform Infrared spectroscopy analyses of quartz reveal higher water contents within shear zones than within country rocks, indicating fluid infiltration synchronous with shearing. Stable isotope analyses of quartz and feldspar from mylonites are consistent with an igneous or metamorphic fluid origin. Microstructural observations suggest that the zone morphology with epidote veins, bleached haloes, and flanking discrete paired shear zones was developed predominantly from reaction softening mechanisms. The increase in deformation from bleached rock to flanking shear zones is marked by progressive modal increases in biotite and myrmekite, and modal decreases in K-feldspar, and locally epidote and titanite. Myrmekitic textures recrystallized readily and resulted in progressively greater grain size reduction of feldspar, which aided in the progressive alignment and linkage of the biotite grains, which together concentrated the deformation in bands. Volume reduction resulting from some of the metamorphic reactions may have led to a positive feedback cycle among fluid infiltration, metamorphism and deformation. U-Pb isotope analyses of syn-metamorphic titanite yield an age of ~70 Ma, suggesting the shear zones formed during cooling of the Late Cretaceous (75.5±1.3 Ma) Brown’s Canyon pluton, consistent with their top-to-the-southwest sense of shear, rather than during top-to-the-northeast directed Miocene metamorphic core complex exhumation. Petrography, EBSD analyses, and U-Pb dating of titanite from other (non-discrete) mylonites in the area imply most formed synchronously with the discrete shear zone mylonites. Only rare, scattered mylonites show features consistent with metamorphic core complex exhumation.
Reproductive Biology of Longfin Dace (Agosia chrysogaster) in a Sonoran Desert Stream, Arizona
(1982-05) Kepner, William G.
The longfin dace, Agosia chrysogaster Girard, is the most abundant native minnow of low elevation (< 1,500 m) streams in Arizona, parts of southwestern New Mexico, and northern Mexico. Reproductive life history of longfin dace was examined over a 12-month period (1977-78) in Aravaipa Creek, Graham and Pinal counties, Arizona. Adult males and females are sexually dimorphic, clearly distinguishable by differences in size of fins. Gravid females and tuberculate males persisted throughout the year and spawned in shallow saucer-shaped depressions in sand-bottomed backwaters and runs. Although individual spawning activity was asynchronous, populations reached peak spawning condition at least twice within the year. Peak reproductive activity was during increased discharge in spring and late summer. Fecundity was primarily a function of size. Ovary weight was highly correlated with fecundity and was the most reliable indicator of total mature ova produced.