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Sample records for jurassic navajo sandstone

  1. A New Basal Sauropodomorph Dinosaur from the Lower Jurassic Navajo Sandstone of Southern Utah

    PubMed Central

    Sertich, Joseph J. W.; Loewen, Mark A.

    2010-01-01

    Background Basal sauropodomorphs, or ‘prosauropods,’ are a globally widespread paraphyletic assemblage of terrestrial herbivorous dinosaurs from the Late Triassic and Early Jurassic. In contrast to several other landmasses, the North American record of sauropodomorphs during this time interval remains sparse, limited to Early Jurassic occurrences of a single well-known taxon from eastern North America and several fragmentary specimens from western North America. Methodology/Principal Findings On the basis of a partial skeleton, we describe here a new basal sauropodomorph dinosaur from the Lower Jurassic Navajo Sandstone of southern Utah, Seitaad ruessi gen. et sp. nov. The partially articulated skeleton of Seitaad was likely buried post-mortem in the base of a collapsed dune foreset. The new taxon is characterized by a plate-like medial process of the scapula, a prominent proximal expansion of the deltopectoral crest of the humerus, a strongly inclined distal articular surface of the radius, and a proximally and laterally hypertrophied proximal metacarpal I. Conclusions/Significance Phylogenetic analysis recovers Seitaad as a derived basal sauropodomorph closely related to plateosaurid or massospondylid ‘prosauropods’ and its presence in western North America is not unexpected for a member of this highly cosmopolitan clade. This occurrence represents one of the most complete vertebrate body fossil specimens yet recovered from the Navajo Sandstone and one of the few basal sauropodomorph taxa currently known from North America. PMID:20352090

  2. Supercritical CO2 Migration under Cross-Bedded Structures: Outcrop Analog from the Jurassic Navajo Sandstone

    NASA Astrophysics Data System (ADS)

    Lee, S.; Allen, J.; Han, W.; Lu, C.; McPherson, B. J.

    2011-12-01

    Jurassic aeolian sandstones (e.g. Navajo and White Rim Sandstones) on the Colorado Plateau of Utah have been considered potential sinks for geologic CO2 sequestration due to their regional lateral continuity, thickness, high porosity and permeability, presence of seal strata and proximity to large point sources of anthropogenic CO2. However, aeolian deposits usually exhibit inherent internal complexities induced by migrating bedforms of different sizes and their resulting bounding surfaces. Therefore, CO2 plume migration in such complex media should be well defined and successively linked in models for better characterization of the plume behavior. Based on an outcrop analog of the upper Navajo Sandstone in the western flank of the San Rafael Swell, Utah, we identified five different bedform types with dune and interdune facies to represent the spatial continuity of lithofacies units. Using generated 3D geometrical facies patterns of cross-bedded structures in the Navajo Sandstone, we performed numerical simulations to understand the detailed behavior of CO2 plume migration under the different cross-bedded bedforms. Our numerical simulation results indicate that cross-bedded structures (bedform types) play an important role on governing the rate and directionality of CO2 migration, resulting in changes of imbibition processes of CO2. CO2 migration tends to follow wind ripple laminations and reactivation surfaces updip. Our results suggest that geologically-based upscaling of CO2 migration is crucial in cross-bedded formations as part of reservoir or basin scale models. Furthermore, comparative modeling studies between 3D models and 2D cross-sections extracted from 3D models showed the significant three-dimensional interplay in a cross-bedded structure and the need to correctly capture the geologic heterogeneity to predict realistic CO2 plume behavior. Our outcrop analog approach presented in this study also demonstrates an alternative method for assessing geologic CO2 storage in deep formations when scarce data is available.

  3. Topographic inversion of early interdune deposits, Navajo Sandstone (Lower Jurassic), Colorado Plateau, USA

    NASA Astrophysics Data System (ADS)

    Bromley, Michael

    1992-09-01

    Outliers of Navajo Sandstone (Lower Jurassic Glen Canyon Group) form low paleohills east of the main body of the Formation in the Salt Anticline region of southwestern Colorado. The paleohills consist of interdune deposits which developed topographic inversion during erosion of the Jurassic J-2 unconformity owing to a tough shell of early cemented sandstones and cherty limestones. The interdune deposits accumulated over playa mudstones of the Kayenta Formation which formed in a structural low between the Uncompahgre Uplift and the Paradox Valley salt anticline. Open-framework textures indicate the early formation of quartz or chert cement in sandstone beds immediately above the impermeable playa mudstones. The mudstones enhanced the subsequent formation of wet interdune deposits keeping groundwater near the surface. Microcrystalline quartz cements and fresh feldspars suggest that groundwater was alkaline. A source of alkalinity may have been eolian dust carried from emergent Pennsylvanian evaporite intrusions upwind of the playa deposits. The high specific surface of siliceous and evaporite dusts combined with shallow groundwater and high evaporation rates resulted in the rapid formation of quartzitic silcrete crusts above the playa mudstone aquacludes. As these early silcretes were buried, the impermeable mudstone foundations beneath them continued to serve as aquacludes. The inclined potentiometric surface of perched water tables above the isolated aquacludes intersected the land surface at progressively higher levels as the mudstone lenses were buried. Groundwater moving laterally from above the aquacludes carried dissolved material towards the inclined water tables at their margins. This mobilized material was redeposited as early cement where the capillary fringe intersected the land surface. As the land surface aggraded vertically, the zone of cement formation migrated laterally in response of a change of the relative positions of the land surface and an inclined perched water table. The final products of this process were topographic remnants of Navajo Sandstone with a resistant rind of cemented material enclosing a core of leached, compacted and friable sandstones. Erosion of the J-2 unconformity left the cemented rind in relief while removing all material around it. The resulting hills survived the onlap of the Middle Jurassic Entrada Formation, leaving considerable relief beneath the unconformity.

  4. An example of liquefaction-induced interdune sedimentation from the early Jurassic Navajo Sandstone, USA

    NASA Astrophysics Data System (ADS)

    Bryant, Gerald; Monegato, Giovanni; Miall, Andrew

    2013-11-01

    Extensive outcrops of Navajo Sandstone in the southwestern United States expose eolian dune deposits that are subdivided in a complex array of foresets and bounding surfaces. In the Glen Canyon region, and other places, this architecture is frequently disrupted by large-scale, soft-sediment deformation features. These features have been attributed to episodic liquefaction events that affected saturated sand below the level of the interdune surface. Though erosional truncation of deformation features indicates that liquefaction often occurred in the uppermost levels of Navajo dune deposits, very few paleotopographic disruptions due to subsurface deformation have been documented. Navajo Sandstone outcrops in West Canyon, Utah, provide unusually comprehensive exposure of architectural details linking large-scale deformation features and associated interdune deposits, enabling a well constrained appraisal of their genesis. At this location, a 23 m succession of sandstone, mudstone, carbonate, and chert deposits overlies a zone of deformation that extends, laterally, for hundreds of meters. This horizontally stratified lens occupies an abrupt synform along a bounding surface between successive crossbeds that otherwise appears as a featureless, sub-horizontal plane. Large-scale foresets below this bounding surface oversteepen at the margins of the synform and grade downdip into contorted stratification and structureless expanses. The authors propose that liquefaction in the Jurassic erg caused localized subsidence of a minor portion of a dry interdune surface to a position several meters below the contemporary water table. A succession of hyperpycnal sand flows, lacustrine evaporites, and eolian sheet and dune deposits filled this depression prior to the advance of large dunes across the site. The process/response dynamics evident in this outcrop suggest that deformation may have exercised significant, non-systematic control over depositional architectures in areas of the erg prone to liquefaction. Similar dynamics are unknown from modern desert environments and their intrinsic scale defies laboratory simulation; therefore, close investigation of these ancient features is essential for exploring the full range of depositional controls that may be encountered in other ancient eolianites on Earth and in eolian accumulations on other planets.

  5. Implications to exploration of porosity relationships and paragenetic sequences, Jurassic Navajo (Nugget) sandstone, Utah, and southwestern Wyoming

    SciTech Connect

    Uygur, K.; Picard, M.D.

    1984-07-01

    The authors have studied in outcrop and in the subsurface the reservoir characteristics and diagenesis of the Early Jurassic, eolian, Navajo (Nugget) Sandstone in Utah and southwestern Wyoming. Principal topics include: texture, framework constituents, intergranular and intragranular cements, matrix, directional porosity, porosity types, and hydraulic conductivity. Characteristics of the sandstone are related to variations in dune and interdune environments, fluctuating ground water chemistry, and postdepositional environments. Diagenesis, in which an open-system diagenetic model is considered, superimposes and is influenced by these variations and events. Compaction of the sandstone due to mechanical rearrangement of detrital grains and intergranular pressure solution played little or no role in modification of porosity or hydraulic conductivity. Likely, they account for not more than 5% of the porosity reduction. Greatest porosity reduction (16%) was by cementation. Present mean total porosity is 19%, ranging from 3 to 35%.

  6. Porosity and grain size controls on compaction band formation in Jurassic Navajo Sandstone

    NASA Astrophysics Data System (ADS)

    Schultz, Richard A.; Okubo, Chris H.; Fossen, Haakon

    2010-11-01

    Determining the rock properties that permit or impede the growth of compaction bands in sedimentary sequences is a critical problem of importance to studies of strain localization and characterization of subsurface geologic reservoirs. We determine the porosity and average grain size of a sequence of stratigraphic layers of Navajo Sandstone that are then used in a critical state model to infer plastic yield envelopes for the layers. Pure compaction bands are formed in layers having the largest average grain sizes (0.42-0.45 mm) and porosities (28%), and correspondingly the smallest values of critical pressure (˜22 MPa) in the sequence. The results suggest that compaction bands formed in these layers after burial to ˜1.5 km depth in association with thrust faulting beneath the nearby East Kaibab monocline, and that hardening of the yield caps accompanied compactional deformation of the layers.

  7. Porosity and grain size controls on compaction band formation in Jurassic Navajo Sandstone

    USGS Publications Warehouse

    Schultz, Richard A.; Okubo, Chris H.; Fossen, Haakon

    2010-01-01

    Determining the rock properties that permit or impede the growth of compaction bands in sedimentary sequences is a critical problem of importance to studies of strain localization and characterization of subsurface geologic reservoirs. We determine the porosity and average grain size of a sequence of stratigraphic layers of Navajo Sandstone that are then used in a critical state model to infer plastic yield envelopes for the layers. Pure compaction bands are formed in layers having the largest average grain sizes (0.420.45 mm) and porosities (28%), and correspondingly the smallest values of critical pressure (-22 MPa) in the sequence. The results suggest that compaction bands formed in these layers after burial to -1.5 km depth in association with thrust faulting beneath the nearby East Kaibab monocline, and that hardening of the yield caps accompanied compactional deformation of the layers.

  8. Contrasting styles of large-scale displacement of unconsolidated sand: examples from the early Jurassic Navajo Sandstone on the Colorado Plateau, USA

    NASA Astrophysics Data System (ADS)

    Bryant, Gerald

    2015-04-01

    Large-scale soft-sediment deformation features in the Navajo Sandstone have been a topic of interest for nearly 40 years, ever since they were first explored as a criterion for discriminating between marine and continental processes in the depositional environment. For much of this time, evidence for large-scale sediment displacements was commonly attributed to processes of mass wasting. That is, gravity-driven movements of surficial sand. These slope failures were attributed to the inherent susceptibility of dune sand responding to environmental triggers such as earthquakes, floods, impacts, and the differential loading associated with dune topography. During the last decade, a new wave of research is focusing on the event significance of deformation features in more detail, revealing a broad diversity of large-scale deformation morphologies. This research has led to a better appreciation of subsurface dynamics in the early Jurassic deformation events recorded in the Navajo Sandstone, including the important role of intrastratal sediment flow. This report documents two illustrative examples of large-scale sediment displacements represented in extensive outcrops of the Navajo Sandstone along the Utah/Arizona border. Architectural relationships in these outcrops provide definitive constraints that enable the recognition of a large-scale sediment outflow, at one location, and an equally large-scale subsurface flow at the other. At both sites, evidence for associated processes of liquefaction appear at depths of at least 40 m below the original depositional surface, which is nearly an order of magnitude greater than has commonly been reported from modern settings. The surficial, mass flow feature displays attributes that are consistent with much smaller-scale sediment eruptions (sand volcanoes) that are often documented from modern earthquake zones, including the development of hydraulic pressure from localized, subsurface liquefaction and the subsequent escape of fluidized sand toward the unconfined conditions of the surface. The origin of the forces that produced the lateral, subsurface movement of a large body of sand at the other site is not readily apparent. The various constraints on modeling the generation of the lateral force required to produce the observed displacement are considered here, along with photodocumentation of key outcrop relationships.

  9. Sandstone Formation on the Navajo Loop Trail

    USGS Multimedia Gallery

    Views along the Navajo Loop Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandston...

  10. Ground-water conditions in the Navajo Sandstone in the central Virgin River basin, Utah

    USGS Publications Warehouse

    Cordova, R.M.

    1978-01-01

    The central Virgin River basin, Utah, includes about 1,000 square miles (2,600 square kilometers) in the drainage basin of the Virgin River downstream from the Hurricane Cliffs. The Navajo Sandstone of Late Triassic(?) and Jurassic age crops out in 234 square miles (606 square kilometers) of the basin and underlies younger rocks in about 450 square miles (1,200 square kilometers) of the basin.

  11. Downslope coarsening in aeolian grainflows of the Navajo Sandstone

    NASA Astrophysics Data System (ADS)

    Loope, David B.; Elder, James F.; Sweeney, Mark R.

    2012-07-01

    Downslope coarsening in grainflows has been observed on present-day dunes and generated in labs, but few previous studies have examined vertical sorting in ancient aeolian grainflows. We studied the grainflow strata of the Jurassic Navajo Sandstone in the southern Utah portion of its outcrop belt from Zion National Park (west) to Coyote Buttes and The Dive (east). At each study site, thick sets of grainflow-dominated cross-strata that were deposited by large transverse dunes comprise the bulk of the Navajo Sandstone. We studied three stratigraphic columns, one per site, composed almost exclusively of aeolian cross-strata. For each column, samples were obtained from one grainflow stratum in each consecutive set of the column, for a total of 139 samples from thirty-two sets of cross-strata. To investigate grading perpendicular to bedding within individual grainflows, we collected fourteen samples from four superimposed grainflow strata at The Dive. Samples were analyzed with a Malvern Mastersizer 2000 laser diffraction particle analyser. The median grain size of grainflow samples ranges from fine sand (164 ?m) to coarse sand (617 ?m). Using Folk and Ward criteria, samples are well-sorted to moderately-well-sorted. All but one of the twenty-eight sets showed at least slight downslope coarsening, but in general, downslope coarsening was not as well-developed or as consistent as that reported in laboratory subaqueous grainflows. Because coarse sand should be quickly sequestered within preserved cross-strata when bedforms climb, grain-size studies may help to test hypotheses for the stacking of sets of cross-strata.

  12. Blueberries on Earth and Mars: Correlations Between Concretions in Navajo Sandstone and Terra Meridiani on Mars.

    NASA Astrophysics Data System (ADS)

    Mahaney, W. C.; Milner, M. W.; Netoff, D.; Dohm, J.; Kalm, V.; Krinsley, D.; Sodhi, R. N.; Anderson, R. C.; Boccia, S.; Malloch, D.; Kapran, B.; Havics, A.

    2008-12-01

    Concretionary Fe-Mn-rich nodular authigenic constituents of Jurassic Navajo sandstone (moki marbles) bear a certain relationship to similar concretionary forms ('blueberries') observed on Mars. Their origin on Earth is considered to invoke variable redox conditions with underground fluids penetrating porous quartz-rich sandstone leading to precipitation of hematite and goethite-rich material from solution, generally forming around a central nucleus of fine particles of quartz and orthoclase, recently verified by XRD and SEM-EDS analyses. At the outer rim/inner nucleus boundary, bulbous lobes of fine-grained quartz often invade and fracture the outer rim armored matrix. The bulbous forms are interpreted to result from fluid explusion from the inner concretionary mass, a response to pressure changes accompanying overburden loading. Moki marbles, harder than enclosing rock, often weather out of in situ sandstone outcrops that form a surface lag deposit of varnished marbles that locally resemble desert pavement. The marbles appear morphologically similar to 'blueberries' identified on the martian surface in Terra Meridiani through the MER-1 Opportunity rover. On Earth, redox fluids responsible for the genesis of marbles may have emanated from deep in the crust (often influenced by magmatic processes). These fluids, cooling to ambient temperatures, may have played a role in the genesis of the cemented outer rim of the concretions. The low frequency of fungi filaments in the marbles, contrasts with a high occurrence in Fe-encrusted sands of the Navajo formation [1], indicating that microbial content is of secondary importance in marble genesis relative to the fluctuating influx of ambient groundwater. Nevertheless, the presence of filaments in terrestrial concretions hints at the possibility of discovering fossil/extant life on Mars, and thus should be considered as prime targets for future reconnaissance missions to Mars. 1] Mahaney, W.C., et al. (2004), Icarus, 171, 39-53.

  13. Geohydrology of the Navajo sandstone in western Kane, southwestern Garfield, and southeastern Iron counties, Utah

    USGS Publications Warehouse

    Freethey, G.W.

    1988-01-01

    The upper Navajo and Lamb Point aquifers in the Navajo Sandstone are the principal source of water for the city of Kanab, irrigation, stock, and for rural homes in the study area. Well logs and outcrop descriptions indicate the Navajo Sandstone consists of the Lamb Point Tongue and an unnamed upper member that are separated by the Tenney Canyon Tongue of the Kayenta Formation. The main Kayenta Formation underlies the Lamb Point Tongue. The Lamb Point Tongue and the upper member of the Navajo Sandstone are saturated and hydraulically connected through the Tenney Canyon Tongue. Available data indicate that precipitation percolates to the groundwater reservoir where the Navajo Sandstone crops out. Estimates of the rate of recharge at the outcrop range from 0.1 to as much as 2.8 in/yr. Water level data indicate that water moves from the upper member of the Navajo Sandstone, through the Tenney Canyon Tongue, and into the Lamb Point Tongue. Lateral flow is generally from the outcrop areas toward the incised canyons formed by tributaries of Kanab Creek and Johnson Wash. Direction and rate of groundwater movement and the location and character of the natural hydrologic boundaries in the northern part of the area where the Navajo Sandstone is buried cannot be determined conclusively without additional water level data. (Author 's abstract)

  14. CO2-Driven Convection Produced the Vertical Distribution of Sandstone Colors and Iron Concretions in Navajo Sandstone at Zion National Park, Utah (USA)

    NASA Astrophysics Data System (ADS)

    Kettler, R. M.; Loope, D. B.

    2011-12-01

    Along cliff faces exposed in Zion National Park (SW Utah), the porous and permeable Navajo Sandstone (Jurassic) is 700 m thick, and is capped by impermeable mudrocks and evaporites of the Carmel Formation. Previous workers have documented an areally extensive color pattern that is easily visible across much of southwestern and south-central Utah: the uppermost Navajo Sandstone is nearly white, the middle third of the formation is pink, and the lowermost fraction is reddish brown. To the northwest of the park, however, the formation is uniformly red (likely its primary color; G.B. Nielsen et al., 2009). Spheroidal concretions with dense, iron-oxide-cemented rinds and iron-poor cores are abundant in the pink and brown sandstones. Rhomb-shaped clots of iron oxide cement that are pseudomorphous after siderite are present in the cores of the largest concretions. The color variations are evidence that iron was transported from the upper portion of the Navajo SS to the lower portion. The pseudomorphs are evidence that the concretions are the oxidized remains of siderite-cemented precursors. The vertical iron transport and the precipitation of siderite require similar vertical transport of reducing, CO2-rich formation waters through the Navajo Sandstone. We argue that this circulation was driven in part by groundwater convection beneath a CO2 accumulation that was trapped below the Navajo-Carmel contact. This circulation caused aqueous iron and aqueous carbonate to be displaced downward and to accumulate (in the form of siderite) in the lower Navajo Sandstone. There are numerous CO2 reservoirs in the Colorado Plateau region; the gas was derived mainly from mantle sources. We hypothesize that, in the late Tertiary, the Carmel Formation capped a broad, structurally high accumulation of CO2 and CH4 in the Navajo Sandstone. The CH4 bleached the upper portion of the sandstone, releasing Fe2+ into the formation water. CO2 dissolved in the water, thereby increasing its density, and causing it to sink. The alkalinity of this down-welling water gradually increased as aqueous CO2 was either consumed via alteration of detrital feldspar grains or lost via degassing. Siderite then started to precipitate, and continued to precipitate as long as a source of iron was present in the down-welling water. Finally, the siderite was oxidized when uplift of the Colorado Plateau led to loss of the gas cap and ingress of oxidizing groundwater. Increased interest in the fate of CO2 injected into porous rocks has prompted detailed modeling of the convective overturn of the formation waters that underlie CO2 accumulations. The distribution and paragenesis of iron oxides in the Navajo Sandstone of southwestern Utah provide a well-exposed end product of this important geologic process.

  15. Characterization of Navajo Sandstone concretions: Mars comparison and criteria for distinguishing diagenetic origins

    NASA Astrophysics Data System (ADS)

    Potter, Sally L.; Chan, Marjorie A.; Petersen, Erich U.; Dyar, M. Darby; Sklute, Elizabeth

    2011-01-01

    The eolian Jurassic Navajo Sandstone spheroidal hydrous ferric oxide (HFO) concretions are divided into two size classes: macro-concretions of > 5 mm diameter and micro-concretions of < 5 mm diameter. Three internal structural end-members of macro-concretions are described as rind, layered, and solid. Two end-members of micro-concretions are rind and solid. Chemical and mineralogical gradients (μm- to mm-scale) are identified with QEMSCAN (Quantitative Elemental Mineralogy using a SCANning electron microscope) and visible to near infrared (VNIR) reflectance spectroscopy. Three HFO phases are identified using VNIR reflectance spectroscopy. An amorphous HFO phase is typically located in the rinds. Goethite is present along interior edges of rinds and throughout the interiors of layered and solid concretions. Hematite is present in the centers of rind concretions. A synthesis of petrographic, mineralogical and chemical analyses suggests that concretions grow pervasively (as opposed to radially expanding). Our model proposes that concretions precipitate initially as an amorphous HFO that sets the radius and retains some original porosity. Subsequent precipitation fills remaining pore space with younger mineral phases. Inward digitate cement crystal growth corroborates concretion growth from a set radius toward the centers. Internal structure is modified during late stage precipitation that diffuses reactants through semi-permeable rinds and overprints the interiors with younger cements. Physical characterization of textures and minerals provides diagnostic criteria for understanding how similar concretions ("blueberries") form in Meridiani Planum, Mars. The analogous Navajo Sandstone concretions show similar characteristics of in situ self-organized spacing, spheroidal geometries, internal structures, conjoined forms, and precursor HFO phases that dehydrate to goethite or hematite. These characteristics indicate a common origin via groundwater diagenesis.

  16. Naturally weathered feldspar surfaces in the Navajo Sandstone aquifer, Black Mesa, Arizona: Electron microscopic characterization

    USGS Publications Warehouse

    Zhu, Chen; Veblen, D.R.; Blum, A.E.; Chipera, S.J.

    2006-01-01

    Naturally weathered feldspar surfaces in the Jurassic Navajo Sandstone at Black Mesa, Arizona, was characterized with high-resolution transmission and analytical electron microscope (HRTEM-AEM) and field emission gun scanning electron microscope (FEG-SEM). Here, we report the first HRTEM observation of a 10-nm thick amorphous layer on naturally weathered K-feldspar in currently slightly alkaline groundwater. The amorphous layer is probably deficient in K and enriched in Si. In addition to the amorphous layer, the feldspar surfaces are also partially coated with tightly adhered kaolin platelets. Outside of the kaolin coatings, feldspar grains are covered with a continuous 3-5 ??m thick layer of authigenic smectite, which also coats quartz and other sediment grains. Authigenic K-feldspar overgrowth and etch pits were also found on feldspar grains. These characteristics of the aged feldspar surfaces accentuate the differences in reactivity between the freshly ground feldspar powders used in laboratory experiments and feldspar grains in natural systems, and may partially contribute to the commonly observed apparent laboratory-field dissolution rate discrepancy. At Black Mesa, feldspars in the Navajo Sandstone are dissolving at ???105 times slower than laboratory rate at comparable temperature and pH under far from equilibrium condition. The tightly adhered kaolin platelets reduce the feldspar reactive surface area, and the authigenic K-feldspar overgrowth reduces the feldspar reactivity. However, the continuous smectite coating layer does not appear to constitute a diffusion barrier. The exact role of the amorphous layer on feldspar dissolution kinetics depends on the origin of the layer (leached layer versus re-precipitated silica), which is uncertain at present. However, the nanometer thin layer can be detected only with HRTEM, and thus our study raises the possibility of its wide occurrence in geological systems. Rate laws and proposed mechanisms should consider the possibility of this amorphous layer on feldspar surface. ?? 2006 Elsevier Inc. All rights reserved.

  17. Diagenetic analogs to hematite regions on Mars: examples from Jurassic sandstones of southern Utah, USA

    NASA Astrophysics Data System (ADS)

    Beitler, Brenda; Chan, Marjorie A.; Parry, William T.; Ormo, Jens O.; Komatsu, Goro

    2004-11-01

    Diagenetic hematite concretions are common in the eolian Jurassic Navajo Sandstone in southern Utah (and some correlative units in Arizona and Nevada). The zones of alteration formed by structurally and stratigraphically influenced subsurface groundwater flow and localized iron oxide precipitation within porous sedimentary rocks. In many geologic systems on Earth, iron is a sensitive fluid flow indicator1. Mobilization and precipitation of iron oxides and sulfides requires specific variations in fluid chemistry. Precipitation of iron oxides in discrete concretionary zones further requires specific host rock characteristics. These characteristic color variations and zones of mineralization in the Jurassic Navajo Sandstone occur in a variety of cementation patterns with structural and stratigraphic relationships that have been well documented. Iron for the concretions is likely sourced internally from hematite grain coatings. Near surface, meteoric waters and processes of weathering commonly distribute disseminated iron films that impart a pink to orange-red color to the sandstone early in the depositional or burial history. The disseminated iron oxides are commonly mobilized and removed by reducing fluids, leaving the sandstone white. When these fluids mix with oxidizing groundwater in the Utah example, concentrated hematite precipitates, typically in the form of spherical balls. Many other concretion geometries commonly occur where anisotropy and preferential fluid flow pathways exist. Some of these shapes include pipes, sheets, bulbs, angular bricks, and repetitive bands. The differing geometries appear to be primarily a function of permeability barriers and pathways. Both sandstone coloration and the presence of hematite concretions (+/- other iron oxide minerals) record evidence of past fluid flow and reactions in subsurface sedimentary rocks. These are products of low-temperature, near-surface, hydrologic, chemical diagenetic reactions. Biomediation can also enhance the diagenetic precipitation of cements. In addition to elucidating a complex history of fluid flow in Utah subsurface, analysis of these concretions can help us to better understand the recently discovered hematite concretions on Mars. The NASA Mars Exploration Rover (MER), Opportunity has discovered spherical nodules in Meridiani Planum, that have been identified to be predominately hematite in composition5,6. These Mars concretions bear a remarkable resemblance to hematite-cemented concretions in sandstones of southern Utah. Hematite is one of few minerals currently found on Mars that can be genetically linked directly to water-related processes7. Although the general process of chemical precipitation has been proposed, diagenetic concretionary precipitation, or ferruginization, has been previously overlooked as a potential formation mechanism. This terrestrial analog in Utah has important implications for biomediated precipitation and for subsurface and potentially atmospheric chemical conditions on Mars.

  18. Aquifer tests of the Navajo sandstone near Caineville, Wayne County, Utah

    USGS Publications Warehouse

    Hood, J.W.; Danielson, T.W.

    1979-01-01

    Ground water in the Navajo Sandstone near Caineville, Wayne County, Utah, was studied during 1975-77 as part of an investigation of water in bedrock in the lower Dirty Devil River basin area. The purpose of the study near Caineville was to determine the water-bearing properties of the Navajo by utilizing data obtained mainly during test drilling and aquifer testing by the Intermountain Power Project.

  19. Eolian sabkha sandstones in the Nugget Sandstone (Jurassic), Vernal area, Utah

    SciTech Connect

    Schenk, C.J.; Peterson, F. )

    1991-06-01

    The Jurassic Nugget Sandstone in the Vernal, Utah, area is characterized by thick (up to 25 m) sets of cross-stratified eolian dune sandstone separated by either erosional planar bounding surfaces or thin (mostly < 3 m) sandstones interpreted as sabkha sandstones. Structures in Nugget sabkha sandstones are predominantly wavy or irregular bedding and thin, remnant sets of dune cross-strata consisting of eolian ripple and avalanche strata. The types of sedimentary structures and erosional features in Nugget sabkha sandstones indicate a close relationship between sand deposition and erosion and fluctuations in the local water table. Thin, remnant eolian dune sets are common in Nugget sabkha sandstones. The remnant sets form when dunes migrating across a sabkha are partially wetted as the water table rises slightly (on a scale of tens of centimeters); the lower part of the dune with wetted sand remains on the sabkha as the rest of the dune continues to migrate. Typically, ripple strata of the dune apron and the toes of avalanche strata are preserved in dune remnants. The avalanche strata, being slightly coarser grained, are preferentially deflated, leaving microtopography. This topography is commonly filled in with ripple strata that form as dry sand again blows across the sabkha. Stacked sets of remnant dunes separated by erosional surfaces illustrate the control of sand deposition on eolian sabkhas by the local water table.

  20. Slope and deep shelf gully sandstones, Upper Jurassic, east Greenland

    SciTech Connect

    Surlyk, F.

    1987-04-01

    The Upper Jurassic Hareelv Formation of Jameson Land, East Greenland, occurs in an area of 60 x 75 km. It consists of 200-500 m of black shale with thick, closely spaced sandstone bodies. The sandstones fill deep, steep-walled gullies and elongate scours, or form more regular, laterally extensive, parallel-sided, but erosive gully mouth or lobe deposits. Both types of sandstone bodies occur completely juxtaposed, and systematic vertical or lateral trends in bed thickness or grain size have not been observed. The sands were deposited in a deep-water shelf basin by high-density turbidity currents traveling from basin-margin source areas. A northeastern source area was represented by a short-lived, rapidly prograding delta, whereas the main, northwestern source area was a shallow, sandy barrier occurring along the length of a major north-northeast-striking fault-controlled slope. Voluminous turbidity currents probably were triggered by earthquakes in the fault zone. The resulting slope and basinal sand bodies are up to 50 m thick and hundreds of meters wide, and may be more than 5 km long in a downcurrent direction. They occur in a thick, rich oil-prone source rock. Thus, they may form potential stratigraphic reservoirs and help drain the source rock. The Hareelv Formation shows important similarities to the ramp facies model for delta-fed sand-rich turbidite systems; however, the formation is mainly tectonically controlled and independent of eustatic sea level changes. The Hareelv Formation may serve as a model for an unusual type of stratigraphic hydrocarbon reservoir, and at least one North Sea oil field seems to have formed in an analogous setting. 10 figures.

  1. Mineralogical Characterization of Navajo Sandstone Iron Oxide Concretions Using QEMSCAN and Reflectance Spectroscopy; Analogue for Martian Diagenetic Processes

    NASA Astrophysics Data System (ADS)

    Potter, S. L.; Chan, M. A.; Petersen, E. U.

    2008-03-01

    The Navajo Sandstone concretions were evaluated to detect mineralogical changes and chemical gradients. Sequential relationships suggest an evolution of phases of cements. The Mars "blueberries" may have a similar evolution of cements.

  2. Conditions and implications for compaction band formation in the Navajo Sandstone, Utah

    NASA Astrophysics Data System (ADS)

    Fossen, Haakon; Schultz, Richard A.; Torabi, Anita

    2011-10-01

    Observations from quartz-rich eolian Navajo Sandstone in the Buckskin Gulch site in southernmost Utah show that pure compaction bands only occur in sandstones where current porosity > 0.29 3, permeability > 10 7 darcy, and grain size > 0.4 mm - properties restricted to the lower and most coarse-grained and well-sorted parts of grain flow units within the dune units. Hence a direct correlation between stratigraphy and band occurrence has been established that can be used to predict deformation band occurrences in similar sandstone reservoirs. We show that the pure compaction bands formed perpendicular to a subhorizontal ?1, bisecting conjugate sets of shear-enhanced compaction bands. The latter bands locally developed into shear-dominated bands that transect entire dune units, suggesting that an increase in the amount of simple shear promotes band propagation into less porous and permeable lithologies. Stress considerations indicate that, as a continuous and overlapping sequence of events, pure compaction bands in quartz-rich Navajo Sandstone initiated at 10-20 MPa (1 km depth), followed by shear-enhanced compaction bands that locally developed into more stratigraphically extensive shear-dominated bands. The rare combination of special lithologic and stress conditions may explain why pure compaction bands are rarely observed in naturally deformed sandstones.

  3. Frisco City sandstone: Upper Jurassic play in southern Alabama

    SciTech Connect

    Montgomery, S.L.; Baria, L.R.; Handford, C.R.

    1997-10-01

    The Frisco City sandstone play in southern Alabama is an example of hydrocarbon entrapment on the flanks of basement erosional features, with principal reservoirs occurring in proximal alluvial-fan to marine shoreface facies. Productive fields are developed on four-way closures of complex geometry, with reservoir sandstones showing maximum thickness along the margins of basement highs that are roughly 1.3-5.18 km{sup 2} in size and have 136-151 m of relief. Detailed analysis of sandstone facies indicates a downdip progression from alluvial-fan through wadi, eolian, beach, tidal-flat, and shoreface deposits. A sequence stratigraphic model based on identification of backstepping strata representing successive transgressive events is useful in predicting maximum reservoir occurrence in the vicinity of inselbergs. Reservoir quality in productive sandstones is high, with porosities ranging from 13 to 27% and permeabilities of 50 md to 5 d. Hydrocarbon occurrence is related to the distribution of high-quality source rock in the Smackover Formation and to maturation history.

  4. Lower Jurassic Navaho-Aztec-Equivalent Sandstones in southern Arizona and their paleogeographic significance

    SciTech Connect

    Bilodeau, W.L.; Keith, S.B.

    1986-06-01

    Thick sequences of Lower Jurassic rhyolitic and andesitic volcanic rocks in several mountain ranges of southern Arizona contain interbedded quartzarenites. Locally up to 250 m thick, these sandstone lenses, composed of well-sorted and well-rounded quartz grains, commonly contain large-scale cross-stratification and are considered to be eolian sand deposits. The eolian sands were blown up against the continental side of the Early Jurassic volcanic arc that trended northwest-southeast across the southwestern margin of the North American continent and/or plate at that time. Paleocurrent data suggest southerly eolian transport of the sands from the Colorado Plateau area. Correlation of these sandstones with the Lower Jurassic Navaho and Aztec Sandstones is indicated by the paleocurrent data as well as radiometric dating of the interbedded volcanics. Eolian sand transport southward across central Arizona in the Early Jurassic indicates that the Mogollon highlands either did not then exist, or were merely low, discontinuous inselbergs on a broad back-arc ramp, more appropriately called the Mogollon slope.

  5. Haynesville sandstone reservoirs in the Updip Jurassic trend of Alabama

    SciTech Connect

    Kugler, R.L.; Mink, R.M.

    1994-09-01

    Subsequent to the 1986 drilling of the 1 Carolyn McCollough Unit 1-13 well, which initiated production from the Frisco City sand of the Haynesville Formation in Monroe County, Alabama, seven Haynesville fields have been established in Covington, Escambia, and Monroe counties. Initial flow rates of several hundred BOPD are typical for wells in these fields, and maximum rates exceed 2000 BOPD in North Frisco City field. As of August 1993, these fields produced more than 3,400,000 bbl of oil and 4,000,000 mcf of gas from depths of 12,000 to 13,000 ft. Haynesville sandstone reservoirs are concentrated in two distinct areas: (1) an eastern area (Hickory Branch, North Rome, and West Falco fields; API oil gravity = 40{degrees}) in the Conecuh embayment and (2) a western area (Frisco City, North Frisco City, southeast Frisco City, and Megargel fields; API oil gravity = 58-59{degrees}) on the Conecuh ridge complex. Eastern fields are productive from Haynesville sandstone, which is not continuous with the two distinct, productive sandstone bodies in western fields, the Frisco City sand and the Megargel sand. Hydrocarbon traps are structural or combination traps associated with basement paleohighs. Reservoir bodies generally consist of conglomerate (igneous clasts in western fields; limestone clasts in eastern fields), sandstone (subarkose-arkose), and shale (some of which is red) in stacked fining-upward sequences. Shale at the tops of these sequences is bioturbated. These marine strata were deposited in shoal-water braid-delta fronts. Petrophysical properties differ between the two areas. Maximum and average permeability in western fields (k{sub max} = 2000 md; k{sub ave} = 850-1800 md) is an order of magnitude higher than in eastern fields. The distribution of diagenetic components, including a variety of carbonate minerals, evaporate minerals (anhydrite and halite in western fields), and carbonate-replaced pseudomatrix, commonly is related to depositional architecture.

  6. Temperatures of quartz cementation in Jurassic sandstones from the Norwegian continental shelf -- evidence from fluid inclusions

    SciTech Connect

    Walderhaug, O. )

    1994-04-01

    Recent studies of fluid inclusions in quartz overgrowths have shown quartz cementation to have taken place at temperatures within the range 60--145 C in several sandstones from the North Sea and offshore mid-Norway (Malley et al. 1986; Konnerup-Madsen and Dypvik 1988; Burley et al. 1989; Walderhaug 1990; Ehrenberg 1990; Saigal et al. 1992; Nedkvitne et al. 1993). This study aims at determining whether these results are typical for quartz cementation of sandstones by presenting homogenization temperatures for 274 aqueous and 366 hydrocarbon inclusions in quartz overgrowths from Jurassic reservoir sandstones on the Norwegian continental shelf, and by reviewing previously published fluid-inclusion data. Possible explanations for different ranges of homogenization temperatures in different sandstones are also discussed, and possible sources of quartz cement and the effect of hydrocarbon emplacement on quartz cementation are considered.

  7. 3D visualization of liquefaction-induced dune collapse in the Navajo Sandstone, Utah, USA

    NASA Astrophysics Data System (ADS)

    Ford, Colby; Nick, Kevin; Bryant, Gerald

    2015-04-01

    The eolian Navajo Sandstone outcrop on the Canyon Overlook Trail in Zion National Park in Southern Utah is dissected by modern erosion in a way which reveals a great deal of the three-dimensional architecture of a major soft-sediment deformation event. The feature is bounded below by a well-developed interdune complex made up of two superimposed carbonate lenses, above by an irregular truncational surface, and incorporates 3 - 10 m of sandstone over an approximately 2 km area. The material above the deformed interval is undeformed cross-bedded sandstone, with crossbeds downlapping onto the surface of truncation. The stratigraphic confinement of deformation and the irregularity of the upper bounding surface suggests a deformation process which created topography, which was in turn covered by the next upwind dune before it could be eroded flat. The deformed material itself is laterally segmented by a stacked succession of shear surfaces, which all strike approximately perpendicular to the paleo-wind direction and dip at decreasing angles in the down paleo-wind direction. These factors point to the collapse of a major dune into the downwind interdune area, likely initiated by liquefaction in the interdune complex. The foundering of the dune's toe into the liquefied area created a powerful lateral stress field which did not extend significantly into the subsurface. The dune collapse process has been used in the past to describe other soft-sediment deformation features in the Navajo Sandstone, but this site provides a wealth of physical details which were not previously associated with dune collapse. Shear surfaces originate in the interdune deposit as slip between laminae, then the cohesive muds provided support as they were thrust upward to angles of up to 50 degrees. The margins of the site also contain important paleoenvironmental indicators. Dinosaur tracks are exposed both at the extreme upwind and downwind margins of the interdune deposit in and slightly above the deformed interval. In addition, a smaller liquefaction feature is visible in the deposit just below the interdune deposit, far enough away from the main feature to suggest that it is a separate event, not directly caused by the dune collapse. It may have been an earlier episode, or was initiated by the same trigger, but it illustrates the susceptibility of this particular interdune to liquefaction. Details such as the confinement of deformation between irregular bounding surfaces, development of major shear planes, and nearby indicators of liquefaction may be used as new and more robust criteria for the recognition of dune collapse features in other localities and deposits.

  8. Net-Infiltration Map of the Navajo Sandstone Outcrop Area in Western Washington County, Utah

    USGS Publications Warehouse

    Heilweil, Victor M.; McKinney, Tim S.

    2007-01-01

    As populations grow in the arid southwestern United States and desert bedrock aquifers are increasingly targeted for future development, understanding and quantifying the spatial variability of net infiltration and recharge becomes critically important for inventorying ground-water resources and mapping contamination vulnerability. A Geographic Information System (GIS)-based model utilizing readily available soils, topographic, precipitation, and outcrop data has been developed for predicting net infiltration to exposed and soil-covered areas of the Navajo Sandstone outcrop of southwestern Utah. The Navajo Sandstone is an important regional bedrock aquifer. The GIS model determines the net-infiltration percentage of precipitation by using an empirical equation. This relation is derived from least squares linear regression between three surficial parameters (soil coarseness, topographic slope, and downgradient distance from outcrop) and the percentage of estimated net infiltration based on environmental tracer data from excavations and boreholes at Sand Hollow Reservoir in the southeastern part of the study area. Processed GIS raster layers are applied as parameters in the empirical equation for determining net infiltration for soil-covered areas as a percentage of precipitation. This net-infiltration percentage is multiplied by average annual Parameter-elevation Regressions on Independent Slopes Model (PRISM) precipitation data to obtain an infiltration rate for each model cell. Additionally, net infiltration on exposed outcrop areas is set to 10 percent of precipitation on the basis of borehole net-infiltration estimates. Soils and outcrop net-infiltration rates are merged to form a final map. Areas of low, medium, and high potential for ground-water recharge have been identified, and estimates of net infiltration range from 0.1 to 66 millimeters per year (mm/yr). Estimated net-infiltration rates of less than 10 mm/yr are considered low, rates of 10 to 50 mm/yr are considered medium, and rates of more than 50 mm/yr are considered high. A comparison of estimated net-infiltration rates (determined from tritium data) to predicted rates (determined from GIS methods) at 12 sites in Sand Hollow and at Anderson Junction indicates an average difference of about 50 percent. Two of the predicted values were lower, five were higher, and five were within the estimated range. While such uncertainty is relatively small compared with the three order-of-magnitude range in predicted net-infiltration rates, the net-infiltration map is best suited for evaluating relative spatial distribution rather than for precise quantification of recharge to the Navajo aquifer at specific locations. An important potential use for this map is land-use zoning for protecting high net-infiltration parts of the aquifer from potential surface contamination.

  9. Oxfordian-Kimmeridgian (Late Jurassic) reservoir sandstones in the Witch Ground Graben, U. K. North Sea

    SciTech Connect

    Harker, S.D. Ltd., Aberdeen ); Mantel, K.A. ); Morton, D.J. ); Riley, L.A. )

    1991-03-01

    Oil-bearing Late Jurassic Oxfordian-Kimmeridgian sandstones of the Sgiath and Piper formations are of major economic importance in the Witch Ground Graben. They form the reservoirs in Scott, which in 1993 will be the largest producing North Sea oil field to come on stream for more than a decade. Together with Scott, the Piper, Saltire, Tartan, Highlander, Petronella, Rob Roy, and Ivanhoe fields contained almost 2 Bbbl of recoverable reserves in these formations. The Sgiath and Piper represent two phases of Late Jurassic transgression and regression, initially represented by paralic deposited sand culminating in a wave-dominated delta sequence. The history of the Sgiath and Piper formations is reviewed and lithostratigraphic and biostratigraphic correlations presented to illustrate the distribution of the reservoir sandstones.

  10. Groundwater-silicates Reaction Kinetics in the Navajo Sandstone Aquifer, Black Mesa, Arizona (Invited)

    NASA Astrophysics Data System (ADS)

    Zhu, C.

    2009-12-01

    Despite numerous studies of soil profiles and watersheds for critical zone processes, the studies of reaction kinetics in groundwater systems are relatively a few. Yet, aquifers are major sites for water-rock interaction, and a significant segment of the hydrological cycle and global elemental cycling. In this presentation, I will show a multi-discipline study of the Navajo sandstone aquifer at Black Mesa, Arizona. The aeolian sandstone represents some simplest lithology, and the study area has unusually abundant hydrologic, geochemical, isotopic, and paleoclimate data. Solute fluxes along flow paths are supplemented by travel time bounded by 14C and excess 4-He data, from which orders of magnitude estimates of the in situ silicate dissolution rates were calculated. These rates show two to five orders of magnitude slower than those from laboratory experiments at comparable temperature and pH and at far from equilibrium conditions, and are much slower than those derived from studies of soils and watersheds. Data from some new analytical and microscopic methods show that the reaction kinetics are complex. Stable Si isotopes of dissolved Si in groundwater along a 100 km flow path show 2 per mil variation and as low as -1.42‰, representing the most negative dissolved Si isotope composition so far found for natural waters. Near atomic scale transmission electron microscopy show a thin (~ 10 nm) amorphous layer is present on naturally weathered K-feldspars in the aquifer, which requires re-consideration of the details of surface reaction controlled mechanism. However, the new hypothesis of strongly coupled dissolution and precipitation reactions that we have been advancing in recent years appear to be able to explain part of the well-known apparent field-lab discrepancy. The slow precipitation of secondary minerals raised the groundwater saturation state with respect to feldspars to close to equilibrium, and thus retard the feldspar dissolution rates. Our recent laboratory experiments that complement the field study supports the hypothesis. Zhu, C. (2005) In situ feldspar dissolution rates in an aquifer. Geochimica et Cosmochimica Acta v. 69, no.6, 1435-1453, 2005. Zhu, C. Veblen, D.R., Blum, A.E, Chipera, S. (2006) Naturally weathered feldspar surfaces in the Navajo Sandstone aquifer, Black Mesa, Arizona: Electron microscopic characterization. Geochimica et Cosmochimica Acta v. 70, no.18, 4600-4616, 2006 doi:10.1016/j.gca.2006.07.013. Georg, R. B., Zhu, C. Reynolds, R.C., and Halliday, A.N. (2009) Stable silicon isotopes of groundwater, feldspars, and clay coatings in the Navajo Sandstone aquifer, Black Mesa, Arizona, USA. Geochimica et Cosmochimica Acta, v.73, 229-2241. Fu, Q., P ‡Lu, H. ‡Konishi, R. Dilmore, H. Xu, W. E. Seyfried, Jr., and C. Zhu (2009) Coupled alkali-feldspar Dissolution and Secondary Mineral Precipitation in Batch Systems: 1. New Experimental Data at 200°C and 300 bars. Chemical Geology, 91(3), 955-964. Zhu, C., and ‡Lu, P. (2009) Alkali Feldspar Dissolution and Secondary Mineral Precipitation in Batch Systems: 3. Saturation States of Product Minerals and Reaction Paths. Geochimica et Cosmochimica Acta. v.73, p.3171-3120. doi: 10.1016/j.gca.2009.03.015.

  11. Phreatic drainage conduits within quartz sandstone: Evidence from the Jurassic Precipice Sandstone, Carnarvon Range, Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Wray, Robert A. L.

    2009-09-01

    Discrete underground drainage conduits in quartz sandstones are far less common than in limestones. This paper provides field evidence from the quartzose Precipice Sandstone in the Carnarvon Range of south-central Queensland, Australia, for tubular underground drainage networks similar in many ways to limestone conduits. Diameters range from less than 1 or 2 cm to over 1.5 m, most display a near-circular to oval cross-section that seems to suggest phreatic or epiphreatic development, and the internal surfaces of many are case-hardened by secondary silica deposits. A number of the region's perennial springs appear to be fed by such tubes. The dominant vertical jointing of the quartz sandstone and relatively high permeability of the sandstone are important controls on tube formation. Solutional weathering of the sandstone is widespread, and is followed by the removal of loosened sand grains by flowing underground water, the process of 'arenisation'. Tube development would appear to have been happening for a very long time, and may still be occurring. A model for tube network formation is proposed. These findings highlight our potentially poor understanding of groundwater flow within some quartz sandstones, and may have important groundwater management implications.

  12. Diagenetic history of fluvial and lacustrine sandstones of the Hartford Basin (Triassic Jurassic), Newark Supergroup, USA

    NASA Astrophysics Data System (ADS)

    Wolela, A. M.; Gierlowski-Kordesch, E. H.

    2007-04-01

    The early introduction of clays into continental sandstones has been attributed to mechanical infiltration by percolation of clay-rich surface waters into grain framework or cutans formed from pedogenic processes. The discovery of pedogenic mud aggregates as traction-load mud in ancient fluvial deposits suggests that permeability and porosity of terrigenous sandstones can be influenced at deposition and control early diagenetic patterns. This study compares diagenesis in fluvial (subaerially exposed) sandstones with lacustrine (subaqueous) sandstones in a Triassic-Jurassic continental rift basin (Hartford Basin, Newark Supergroup). Diversity of diagenetic minerals and sequence of diagenetic alteration can be directly related to depositional environment. The fluvial sandstones in the New Haven Arkose, East Berlin Formation, and Shuttle Meadow Formation of the Hartford Basin are dominated by concretionary calcite and early calcite cement, infiltrated clays (illite-smectite), pedogenic mud aggregates (smectite and illite-smectite), grain coating clays (illite/hematite, illite-chlorite/hematite), quartz overgrowths, late stage carbonate cements (calcite, ferroan calcite), pore-filling clays (illite, kaolinite with minor amounts of smectite, smectite-chlorite, illite-smectite) and hematite. However, pedogenic processes in these fluvial sandstones retarded the development of quartz and feldspar overgrowths, and carbonate authigenesis, as well as the quality of diagenetically enhanced porosity. Dark gray-black lacustrine (subaqueous) sandstones and mudrocks in the East Berlin and Shuttle Meadow Formations are dominated by pyrite, concretionary dolomite and early dolomite cement, radial grain coating clays (smectite-chlorite, illite-smectite), late stage carbonate cements (dolomite, ferroan dolomite, ankerite), albite and pore-filling clays (smectite-chlorite, illite-smectite, illite-chlorite). Clay minerals exist as detrital, mechanically infiltrated, and neoformed clay. The fluvial sandstones in the New Haven Arkose are dominated by illite. The East Berlin and Shuttle Meadow Formations are dominated by illite in the fluvial sequences and smectite-chlorite and illite-smectite in the lacustrine sandstones. Dolomite, ferroan dolomite, and ankerite are restricted to lacustrine sandstones, whereas calcite and ferroan calcite to fluvial sandstones. Albite predominantly precipitated in lacustrine rather than fluvial environments through intergranular dissolution of plagioclase by acidic meteoric water, dissolution of unstable mafic minerals, and sodium-rich brines and evaporites developed from groundwater. Albitization and carbonate cementation are the most pronounced late stage diagenetic processes affecting both types of Hartford sandstones.

  13. Major discoveries in eolian sandstone: facies distribution and stratigraphy of Jurassic Norphlet sandstone, Mobile Bay, Alabama

    SciTech Connect

    Levy, J.B.

    1985-02-01

    Recent exploratory and development drilling in Mobile Bay, southwest Alabama, has proven prolific gas production from the Norphlet sandstone at depths greater than 20,000 ft with individual well tests of 10-27 MMCFGD. Excellent reservoir qualities are a function of preserved primary porosity and permeability developed in an eolian setting. In Mobile Bay, thick eolian sediments (200-600 ft) lie directly on Pine Hill or Louann evaporites. Three facies of the Norphlet have been recognized: (1) a thin (20-30 ft) basal wet sand flat or sabkha facies, (2) a massive dune facies, and (3) a thin (30-40 ft) upper marine reworked facies. The wet sand flat or sabkha facies is characterized by irregular to wavy horizontally bedded sandstone associated with adhesion ripples. It is probably sporadically developed in response to localized wet lows during earliest Norphlet deposition. The majority of the Norphlet section is characterized by massive wedge-planar and tabular-planar cross-stratified sandstone, interpreted to be stacked dune and dry interdune deposits. Individual dune sets range in height from a few feet to 90 ft. Cross-bed sets exhibit internal stratification patterns similar to large- and small-scale dunes described by G. Kocurek and R. Dott, Jr. The marine reworked facies is characterized by structureless to diffuse or wavy laminated sandstone that reflects a reworking of the dune deposits by the ensuing Smackover transgression. Reservoir quality is affected by textural properties determined by depositional processes associated with these various facies. Diagenetic patterns further reducing reservoir quality occur in the depositionally less-porous sediments. Dune facies sediments exhibit the best reservoir qualities. Variations of reservoir quality within the dune facies are related to dune height and dune versus interdune accumulations.

  14. Acoustic Emission and Ultrasonic Characterization of Jurassic Navajo Formation Deformation During Axisymmetric Compression Testing

    NASA Astrophysics Data System (ADS)

    Rinehart, A. J.; Dewers, T. A.; Holcomb, D. J.; Broome, S. T.

    2011-12-01

    Linking continuum-scale and microscale brittle damage in rock remains a challenge impacting CO2 sequestration, secondary recovery, structural monitoring, and other geotechnical engineering applications. We examine if the mode of micromechanical failure scales directly up to continuum-scale damage-induced velocity anisotropy. Axisymmetric drained lab-dry compression experiments are performed on facies of moderately cemented finely laminated quartz arenite from the Jurassic Navajo Formation, a target reservoir rock for CO2 sequestration in Utah. The tests are 1 unconfined uniaxial compression test, 1 hydrostatic compression test, and 3 triaxial compression tests. Microscale damage is monitored using acoustic emissions (AE) and continuum scale damage is monitored with ultrasonic velocity scans. During the non-hydrostatic tests, three to five unload loops are performed pre-failure, with one unload loop performed post-failure. While stresses are increasing, AEs are monitored continuously using 1.6-mm diameter, 0.5-mm thick PZT-5A pins attached circumferentially around the cylindrical sample, and with 6-mm diameter, 2-mm thick PZT-5A discs at the ends of the sample. Before and after each unload loop, the test is paused and the AE transducers sequentially emit an ultrasonic pulse to measure wave speeds. The resulting elastic wave is detected by the other AE transducers. Post-test, the changing anisotropic velocity structure of the rock during compression and failure is compared to the locations, frequency, and relative moment tensors of the AEs measured between ultrasonic scans. Pre- and post-test visual and x-ray CT scan observations of the sample are compared to the acoustic metrics. These tiered observations of rock damage will further elucidate the scaling of microscale brittle failure to the continuum-scale This work was supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001114. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  15. Reservoir quality of Lower Jurassic muddy sandstone reservoirs, western Sverdrup Basin, Arctic Canada: an SEM study

    SciTech Connect

    Chowdhury, A.N.

    1986-05-01

    Clayey sandstones of the Lower Jurassic King Christian Formation, deposited in progradational sequences of shelf and deltaic environments, are the principal gas reservoirs in the deeper areas (about 2000 m and greater burial depth) of the western Sverdrup basin. The sandstones are dominantly fine-grained and argillaceous. Clay content ranges from 8% to greater than 30%. A scanning electron microscope (SEM) study of these compacted and tight sandstones revealed abundant leached porosity and microporosity in the interstitial detrital clay matrix. Clay diagenesis revealed by SEM includes dissolution of illitic clay matrix and carbonaceous clays, and growth of kaolinite and illite. Clay diagenesis occurred during intermediate to deep burial. The intensity of clay mineral transformation correlates well with organic metamorphic facies. Burial leaching of the clay matrix can be attributed to an increase of P/sub CO/sub 2// and a buildup of H/sup +/ in the pore fluids. Acidic fluids possibly migrated into the reservoir from the underlying and overlying source shales associated with increasing maturation temperatures. Hydrocarbon production from the deeper reservoirs in the western Sverdrup basin will be primarily from secondary leached porosity in the clay matrix, where late-stage cementation was arrested by earlier hydrocarbon migration. Full reservoir quality and potential of these clayey sandstones can be evaluated only by detailed SEM examination of core materials and well cuttings.

  16. Petrology and diagenesis of Upper Triassic and Lower Jurassic graben-fill sandstones of Jameson land basin, central east Greenland

    SciTech Connect

    Davee, K.W.; Mansfield, C.F.

    1986-05-01

    Sands of the Upper Triassic-Lower Jurassic Kap Stewart and Lower Jurassic Neill Klinter Formations were deposited during the early development of a major Jurassic rift basin. Depositional environments have been interpreted as alluvial fan, fluvial, and deltaic for the Kap Stewart, and as tidal estuary for the Neill Klinter. Most of these sandstones are fine to medium-grained quartz and subarkosic wackestones. Clay matrix is abundant and comprises mostly diagenetic kaolinite, illite, and complex clay mixtures derived from the breakdown of labile framework grains, especially plagioclase and biotite. Early emplacement of carbonate cement in some sandstones prevented development of diagenetic clay matrix. The carbonate cement is poikilotopic and constitutes up to 30% of some samples. The current high level of maturity indicated by the quartz-feldspar-lithic composition for these sandstones results from selective diagenetic decomposition of labile grains. The original, more feldspathic compositions reflect less maturity and an earlier stage of basin fill than the Middle Jurassic, high-porosity arenites, which also contain abundant quartz and up to 25% feldspar. Because of Upper Triassic and Lower Jurassic sands were deposited in continental and low-energy marine environments, they likely underwent greater in-situ alteration but less winnowing of labile grains than the overlying Middle Jurassic sands deposited in higher energy marine settings.

  17. Diagenetic quartzarenite and destruction of secondary porosity: An example from the Middle Jurassic Brent sandstone of northwest Europe

    NASA Astrophysics Data System (ADS)

    Harris, Nicholas B.

    1989-04-01

    Significant amounts of feldspar have been dissolved from Middle Jurassic sandstone oil reservoirs in the North Sea (northwest Europe) during burial diagenesis. Sandstones of the Middle Jurassic Brent Group become increasingly quartzose with increasing burial depth. At Stafford field (2500 m depth), sandstones are arkose to subarkose; at Hutton field (3050 m depth), they are subarkose to quartzarenite; and at Lyell field (3500 m depth), sandstones are typically quartzarenite. In spite of extensive feldspar dissolution, the abundance of secondary porosity due to feldspar dissolution is similar for all fields, averaging 2.9% of the total rock volume. Thus, far more feldspar has been dissolved than is recorded as secondary porosity. The limit on preservation of secondary porosity may be largely the effect of the mechanical strength of the rock. An excessive number of large secondary pores lowers the rock strength below the point at which the rock can withstand overburden stress, thus causing collapse of some of the secondary pores.

  18. Diagenetic quartzarenite and destruction of secondary porosity: An example from the Middle Jurassic Brent sandstone of northwest Europe

    SciTech Connect

    Harris, N.B. )

    1989-04-01

    Significant amounts of feldspar have been dissolved from Middle Jurassic sandstone oil reservoirs in the North Sea (northwest Europe) during burial diagenesis Sandstones of the Middle Jurassic Brent Group become increasingly quartzose with increasing burial depth. At Statfjord field (2500 m depth), sandstones are arkose to subarkose; at Hutton field (3050 m depth), they are subarkose to quartzarenite, and at Lyell field (3500 m depth), sandstones are typically quartzarenite. In spite of extensive feldspar dissolution, the abundance of secondary porosity due to feldspar dissolution is similar for all fields, averaging 2.9% of the total rock volume. Thus, far more feldspar has been dissolved than is recorded as secondary porosity. The limit on preservation of secondary porosity may be largely the effect of the mechanical strength of the rock. An excessive number of large secondary pores lowers the rock strength below the point at which the rock can withstand overburden stress, thus causing collapse of some of the secondary pores.

  19. Paleomagnetic Data from the Chugwater Group and Lower Jurassic Nugget Sandstone, Gros Ventre Range, Northwest Wyoming

    NASA Astrophysics Data System (ADS)

    Purcell, C. W.; Geissman, J. W.

    2001-12-01

    The Gros Ventre Range in northwest Wyoming is a Laramide style, Precambrian-cored basement uplift defined by a series of west-northwest trending high-angle reverse faults on its southwest margin. The northeast flank of the range contains a typically gently dipping sequence of Paleozoic to lower Tertiary strata. Southwest of the range, east-verging structures of the Sevier fold-thrust belt come within a few kilometers of the southwest-verging Laramide style, basement involved reverse faults. We have collected paleomagnetic data from hematite-cemented siltstones and fine sandstones of the Triassic Chugwater Group (Lower Triassic(?) Red Peak Formation, Alcova Limestone, Crow Mountain Sandstone, Popo Agie Formation, and Jelm Formation) and hematite-cemented fine to medium sandstones of the Lower Jurassic Nugget Sandstone to determine if the orientation of the Gros Ventre Range has been affected by vertical axis rotation during Cretaceous to early Tertiary contraction of this part of the Cordillera, possibly as a result of differential shortening along basement involved Laramide-style structures. Locally along the northeast flank of the range these strata are deformed large-amplitude overturned to upright folds with west-nortwest trending fold axes, affording rigorous fold tests. We have collected appropriate strata from five general localities along the Gros Ventre River valley, along the northeast margin of the range. NRM directions from much of the collection (over 600 samples) and preliminary thermal demagnetization results are interpreted to indicate that the Gros Ventre Range (assuming that the Phanerozoic section is not detached) has not experienced appreciable vertical axis rotation.

  20. Relationship Between Petrographic Characteristics and the Engineering Properties of Jurassic Sandstones, Hamedan, Iran

    NASA Astrophysics Data System (ADS)

    Heidari, M.; Momeni, A. A.; Rafiei, B.; Khodabakhsh, S.; Torabi-Kaveh, M.

    2013-09-01

    To study the relationship between engineering properties and petrographic characteristics, 20 rock samples were collected from Jurassic sandstones in the Hamedan region, western Iran. The specimens were tested to determine uniaxial compressive strength, point load strength index, tangent modulus, porosity, and dry and saturated unit weights. Samples were also subjected to petrographic examination, which included the observation of 11 parameters and modal analysis. Based on the results of a statistical analysis, polynomial prediction equations were developed to estimate physical and mechanical properties from petrographic characteristics. The results show that textural characteristics are more important than mineral compositions for predicting engineering characteristics. The packing density, packing proximity and grain shape are the petrographic properties that significantly affect the engineering properties of samples. Multivariate linear regression analysis was performed, employing four steps comprising various combinations of petrographic characteristics for each engineering parameter. The optimal equation, along with the relevant combination of petrographic characteristics for estimating the engineering properties of the rock samples is proposed.

  1. Three-dimensional analysis of eolian systems in Jurassic Wingate sandstone

    SciTech Connect

    Nation, M.J.; Blakey, R.C.

    1989-03-01

    Regional bounding surfaces in ancient eolian sequences aid in establishing lateral profiles not previously obtainable using standard stratigraphic methods. Correlation of detailed measured sections permits three-dimensional analysis of erg dynamics in the Jurassic Wingate Sandstone on the Colorado Plateau. Four periods of erg development marked by contrasting styles of eolian architecture are documented in the Salt Anticline region (in ascending stratigraphic order): (1) discontinuous sand sheets, isolated dunes, and aqueous environments; (2) large compound dunes with decreasing amounts of dune margin material; (3) compound dunes and draas alternating with locally thick sandsheet deposits; and (4) widespread dunes and draas prior to erosion by Kayenta fluvial systems. Regional bounding surface characteristics reflect different mechanisms for erg stabilization, including deflation to the water table, climate change, and negative net sand budget. Lateral reconstruction and correlation of erg sequences indicate significant intrabasinal paleogeographic and tectonic controls on eolian systems. Localities removed from the Salt Anticline region contain much larger compound draa deposits and lack extensive accumulations of sand-sheet material. Regional comparison of these characteristics suggests that the salt uplifts modified eolian processes within the Wingate depositional basin. Existence of additional geographic variations not associated with salt tectonism is indicated by local accumulations of noneolian deposits in northeastern Arizona. The use of regional bounding surfaces to construct lateral profiles is a powerful method to establish three-dimensional models of eolian systems. Analysis of erg dynamics in other ancient eolian formations is possible utilizing the criteria documented in the Wingate Sandstone.

  2. Reconstruction of eolian sequences - a function of scale, Jurassic Page sandstone, Arizona

    SciTech Connect

    Kocurek, G.; Knight, J.; Havholm, K.

    1989-03-01

    Interpretation of sequences of ergs and bed forms that comprise an eolian unit is strongly dependent on the scale of mapping. A pentagon-shaped, three-dimensional outcrop of eolian Middle Jurassic Page sandstone near Page, Arizona, measuring 36 m high and nearly 1 km in perimeter, was mapped with the aid of an electronic tacheometer. The extent and orientation of bounding surfaces and sets of cross-strata were mapped in detail, foreset orientation were measured, and a general depiction was made of the lateral and vertical distribution of stratification types within sets and of features associated with the surfaces. The level of mapping is at a middle scale with respect to architectural elements and proved adequate for an interpretation of most bed forms in terms of shape (two or three dimensions, sinuosity, symmetry, and crestline-phase relationships), size (height and width), aerodynamics (overall primary and secondary airflow patterns), and migration behavior (degree of climb and recognition of cyclicity). These interpretations allow the determination of bed-form hierarchy (simple dunes or draas) and of the bed-form type according to the descriptive (crescentic, linear) and dynamic (transverse, oblique, longitudinal) classifications. In conjunction with this level of mapping, large-scale or regional mapping was used in order to identify distinct, stacked, dune-field, and erg deposits that comprise the Page sandstone. Local mapping of the out-crop at a fine scale was necessary for refined interpretation of cyclicity, bed-form size, migration rate, and airflow pattern.

  3. Controls on eolian facies architecture, Middle Jurassic Page Sandstone, Colorado plateau

    SciTech Connect

    Havholm, K.G.; Kocurek, G. )

    1991-03-01

    Eolian systems to not fit simply into basin sedimentation models developed for marine/coastal sequences. Therefore a new conceptual framework was developed linking eolian basin-scale sedimentation patterns to conditions and events within and external to the eolian environment. Controlling factors at this scale are eolian sediment budget, sand supply, water-table fluctuation, and subsidence. These parameters and their relative rates predict eolian system type, genetic stratigraphy, mode of preservation, and resulting facies architecture. This conceptual model allows interpretation of the genetic or event stratigraphy of an eolian sandstone and inference of basinal conditions during its formation. The Page Sandstone, an erg system adjacent to the Middle Jurassic Carmel interior seaway, consists of two laterally continuous accumulations of dry eolian systems, relatively uninterrupted by super surfaces (Harris Wash and upper Thousand Pockets); these are separated by a contrasting eolian condensed zone, which consists of lenses of dry dunefield accumulations truncated by multiple wet super surfaces. The Harris Wash and upper Thousand Pockets represent times of high sand supply and positive sediment budget, with water table well below the sediment surface during a relative lowstand of the Carmel sea. The condensed zone indicates a time of low sand supply, a high but fluctuating water table, and a sediment budget fluctuating from positive to negative. It corresponds to a relative Carmel sea-level rise. In the Page Sandstone single or multiple super surfaces in the eolian system correspond to maximum flood surfaces in the marine system. In contrast, relative sea-level lowstands are represented by erg accumulations uninterrupted by hiatal surfaces.

  4. The stratigraphy of Oxfordian-Kimmeridgian (Late Jurassic) reservoir sandstones in the Witch Ground Graben, United Kingdom North Sea

    SciTech Connect

    Harker, S.D. ); Mantel, K.A. ); Morton, D.J. ); Riley, L.A. )

    1993-10-01

    Oil-bearing Upper Jurassic Oxfordian-Kimmeridgian sandstones of the Sgiath and Piper formations are of major economic importance in the Witch Ground Gaben, United Kingdom North Sea. They form the reservoirs in 14 fields that originally contained 2 billion bbl of oil reserves, including Scott Field, which in 1993 will be the largest producing United Kingdom North Sea oil field to come on stream in more than a decade. The Sgiath and Piper formations represent Late Jurassic transgressive and regressive phases that began with paralic deposition and culminated in a wave-dominated delta system. These phases preceded the major grabel rifting episode (late Kimmeridgian to early Ryazanian) and deposition of the Kimmeridge Clay Formation, the principal source rock of the Witch Ground Graben oil fields. A threefold subdivision of the middle to upper Oxfordian Sgiath Formation is formally proposed, with Scott field well 15/21a-15 as the designated reference well. The basal Skene Member consists of thinly interbedded paralic carbonaceous shales, coals, and sandstones. This is overlain by transgressive marine shales of the Saltire Member. The upper-most Oxfordian Scott Member consists of shallow marine sandstones that prograded to the southwest. The contact of the Sgiath and Piper formations is a basinwide transgressive marine shale (I shale), which can act as an effective barrier to fluid communication between the Sgiath and Piper reservoir sandstones.

  5. Detrital Zircon Ages from Late Jurassic-Early Cretaceous Myrgovaam Basin Sandstones (Rauchua Trough), Western Chukotka, NE Russia

    NASA Astrophysics Data System (ADS)

    Miller, E. L.; Toro, J.; Gehrels, G.; Tuchkova, M.; Katkov, S.

    2004-12-01

    Late Jurassic to Early Cretaceous Myrgovaam Basin sediments (previously Rauchua Trough) are regionally significant because of the stratigraphic constraints they provide on the age and progression of deformation in the Chukotka fold belt, a possible along-strike continuation of the Alaskan Brooks Range fold-and-thrust belt. Existing descriptions of the structural and stratigraphic relations of Myrgovaam Basin sediments to underlying strata are contradictory. Some maps portray the basin fill as deposited unconformably over deformed Triassic and Jurassic strata of the Chukotka fold-belt. In other publications, the deposits are described as structurally detached and imbricated by N-verging thrust sheets (Baranov, 1996). Field studies reveal that underlying strata are tightly folded compared to overlying strata and that the contact is a structural discordance not an unconformity. More locally, we observed arkosic sandstones typical of the Myrgovaam Basin interbedded with underlying Late Jurassic strata or present as submarine channel deposits cut into older rocks, suggesting an original stratigraphic relationship. To reconcile these observations we suggest regional deformation post-dates deposition of Myrgovaam Basin deposits, and that the disharmony in deformational style between underlying thin-bedded Triassic sandstones and shales and (stratigraphically) overlying massive quartzites, is due to their different mechanical properties. Petrographic studies indicate that fine-grained Triassic-early Jurassic sandstones represent a distal recycled orogen source, while Myrgovaam Basin sandstones originated from a proximal orogenic source containing granitoid and crystalline basement rocks (microcline, biotite, muscovite and fragments of multiply deformed schist) and intermediate to felsic volcanic rocks. Laser Ablation ICPMS was used to date zircons (100 grains) from sandstones of the Myrgovaam Basin and compare them to those in Triassic sandstones (300 grains) and verify that Myrgovaam Basin deposits represent a major change in clastic source regions. Zircon populations from Triassic sandstones have age peaks in cumulative probability plots at 247, 298, 380, 453, 504 and 566 Ma (63 percent of zircon population). Only 12 percent of the grains are older than 1.8 Ga. In contrast, zircons from Rauchua Formation sandstones have age peaks at 180, 270, 322, 390-420 (43 percent of the grains). Over 40 percent of the zircons are 1.8-2.2 Ga. The immaturity of sandstones of the Myrgovaam Basin and their abundance of Precambrian zircons, suggest basement-involved faulting during deposition. Since Myrgovaam Basin deposits likely pre-date folding in the Chukotka fold-belt, faulting could be related to either the onset of rifting of the Arctic Alaska-Chukotka plate away from its parental continent or to the beginning of collision-related thrust faulting, but there are no known exposures of 1.8-2.2 Ga rocks in Chukotka. Jurassic zircons, representing a very small part of the population, suggest a proximal magmatic source and provide a maximum age for these strata.

  6. Navajo Dome

    USGS Multimedia Gallery

    Navajo Dome, one of the more notable features within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the...

  7. Navajo Peak

    USGS Multimedia Gallery

    A view of Navajo Peak from Rainbow Point in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the s...

  8. Ground-water flow in the Navajo sandstone in parts of Emery, Grand, Carbon, Wayne, Garfield, and Kane counties, southeast Utah

    USGS Publications Warehouse

    Weiss, Emanuel

    1987-01-01

    A finite-difference model of one layer was constructed to determine groundwater flow directions and magnitudes in the Navajo Sandstone of southeast Utah. Hydraulic head data, hydraulic conductivity data, precipitation data, and other data collected in the area were used in constructing and calibrating the model. Sensitivity of the model to unknown aspects of the groundwater system was investigated. Simulation error attributable to grid-size error was unexpectedly large, but compared to the uncertainty in the groundwater system, simulation error was not large. (USGS)

  9. U Pb ages of detrital zircons from Permian and Jurassic eolian sandstones of the Colorado Plateau, USA: paleogeographic implications

    NASA Astrophysics Data System (ADS)

    Dickinson, William R.; Gehrels, George E.

    2003-12-01

    Detrital zircon grains ( n=468) from eolian sandstones of Permian and Jurassic sand seas on the Colorado Plateau of southwest Laurentia fall into six separable age populations defined by discrete peaks on age-probability plots. The eolian sands include significant contributions from all Precambrian age belts of the Laurentian craton and all key plutonic assemblages of the Appalachian orogen marking the Laurentia-Gondwana suture within Pangaea. Nearly half the detrital zircon grains were derived ultimately from Grenvillian (1315-1000 Ma), Pan-African (750-500 Ma), and Paleozoic (500-310 Ma) bedrock sources lying within or along the flank of the Appalachian orogen. Recycled origins for Appalachian-derived grains, except for temporary residence of synorogenic detritus in the Appalachian foreland basin or in deformed Ouachita flysch and molasses along tectonic strike, are precluded by regional geology and known geochronology from other Laurentian sedimentary assemblages. We infer that transcontinental Permian and Jurassic river systems transported detritus of Appalachian provenance westward across the subdued surface of the Laurentian craton, for deposition as proximate sources for eolian systems feeding the ergs, on unconsolidated fluvial plains, deltas, and strandlines that lay up-paleowind along or near the Cordilleran paleoshoreline north and northeast of the Colorado Plateau. The postulated river systems headed in the remnant Appalachian orogen (Permian) or the incipient Atlantic rift belt (Jurassic), and additional transport of the Appalachian-derived detritus toward the Colorado Plateau was achieved by longshore drift of sediment southward along the Cordilleran paleoshoreline under the influence of prevailing trade winds in the Permian-Jurassic tropics. Only a quarter of the eolianite detrital zircons were derived or recycled from Mesoproterozoic (1470-1335 Ma) and younger Paleoproterozoic (1800-1615 Ma) basement of the Ancestral Rocky Mountains province adjacent to the Colorado Plateau. The final quarter of eolianite detrital zircons were derived from older Paleoproterozoic (2200-1800 Ma) and Archaean (3015-2580 Ma) basement of the Laurentian shield, or recycled from its sedimentary cover. Both Laurentian shield and Ancestral Rockies detritus may have entered the same transcontinental river systems (through tributary streams), or the same Cordilleran strandline system (by longshore drift), responsible for the delivery of Appalachian-derived sediment to positions near the Colorado Plateau ergs. As Colorado Plateau ergs received contributions from all the potential bedrock sources contiguous with Permian-Jurassic Laurentia and its orogenic-taphrogenic margins, detrital zircon studies of analogous ancient erg deposits elsewhere may help test reconstructions of Rodinia and other ancient paleocontinents by providing proxy records of the full age ranges of bedrock sources distributed across the surfaces of entire landmasses.

  10. Hydrocarbon-bearing sandstone in the Upper Jurassic Naknek Formation on the south shore of Kamishak Bay

    USGS Publications Warehouse

    Stanley, Richard G.; Herriott, Trystan M.; Helmold, Kenneth P.; Gillis, Robert J.; Lillis, Paul G.

    2013-01-01

    The presence of an active petroleum system in Kamishak Bay is demonstrated by an outcrop of hydrocarbon-bearing sandstone in the Upper Jurassic Naknek Formation near the south shore of the bay (fig. 1). The outcrop is about 140 km southwest of Homer on a small, unnamed island near the mouth of the Douglas River (fig. 17). The existence of this outcrop was kindly reported to us by Les Magoon (U.S. Geological Survey, emeritus), who also provided a topographic map showing its exact position. The outcrop was mentioned very briefly in publications by Magoon and others (1975, p. 19) and by Lyle and Morehouse (1977, p. E-1), but to our knowledge there are no detailed descriptions of this outcrop or its hydrocarbons in the published scientific literature.

  11. Haynesville sandstone reservoirs in the updip-Jurassic trend of Alabama

    SciTech Connect

    Kugler, R.L.; Mink, R.M.

    1994-12-31

    Since the 1986 drilling of the 1 Carolyn McCollough Unit 1-13 well, which initiated production from the Frisco City sandstone of the Haynesville Formation in Monroe County, Alabama, seven Haynesville fields have been established in Covington, Escambia, and Monroe Counties. Initial flow rates of several hundred BOPD are typical in wells in these fields, and maximum rates exceed 2,000 BOPD in North Frisco City field. As of August 1993, these fields had produced more than 3,400,000 bbl of oil and 4,000,000 Mcf of gas from depths of 12,000 to 13,000 ft. Haynesville sandstone reservoirs are concentrated in two distinct areas: (1) an eastern area (Hickory Branch, North Rome, and West Falco fields; API oil gravity = 40{degrees}) in the Conecuh embayment and (2) a western area (Frisco City, North Frisco City, southeast Frisco City, and Megargel fields, API oil gravity = 58-59{degrees}) on the Conecuh ridge complex. Eastern fields are productive from Haynesville sandstone, which is not continuous with the two distinct, productive sandstone bodies in western fields, the Frisco City sandstone and the Megargel sandstone. Hydrocarbon traps are structural or combination traps associated with basement paleohighs. Reservoir bodies generally consist of conglomerate (igneous clasts in western fields; limestone clasts in eastern fields), sandstone (subarkose-arkose), and shale (some of which is red) in stacked upward-fining sequences. Shale at the tops of these sequences is bioturbated. These marine strata were deposited in shoal-water braid-delta fronts. Maximum and average permeability in western fields (k{sub max} = 2,000 md; k{sub ave} = 850-1,800 md) is an order of magnitude higher than that in eastern fields. The distribution of diagenetic components, including a variety of carbonate minerals, evaporite minerals (anhydrite and halite in western fields), and carbonate-replaced pseudomatrix, commonly is related to depositional architecture.

  12. Stratigraphic analysis of eolian interactions with marine and fluvial deposits, Middle Jurassic Page Sandstone and Carmel Formation, Colorado Plateau, U.S.A.

    SciTech Connect

    Blakey, R.C.; Jones, L.S.; Havholm, K.G.

    1996-03-01

    The eolian Page Sandstone (Middle Jurassic) in south-central Utah and adjacent Arizona consists of multiple mostly eolian sequences and sequence-bounding unconformities (super surfaces). The super surfaces are a powerful correlation tool that provide the basis for a detailed regional stratigraphic analysis of the Page Sandstone and coeval parts of the marine and coastal-plain Carmel Formation. Some Page Sandstone upper surfaces correlate with sharp lithologic breaks in the Carmel Formation that are interpreted as marine flooding surfaces. Others correlate with fluvial surfaces in the Carmel Formation. This study demonstrates that a sequence stratigraphic framework can be applied to sparsely fossiliferous eolian, sabkha, and restricted marine deposits in a marine-coastal setting. Using detailed sedimentologic and stratigraphic studies, tectonic, eustatic, and possibly climatic signals can be differentiated within the complex, cyclic facies patterns displayed in the Page Sandstone and Carmel Formation.

  13. Sandstone Texture

    USGS Multimedia Gallery

    Views along the Navajo Loop Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandston...

  14. Simulation analysis of water-level changes in the Navajo sandstone due to changes in the altitude of Lake Powell near Wahweap Bay, Utah and Arizona

    USGS Publications Warehouse

    Thomas, B.E.

    1986-01-01

    A two-dimensional, finite difference, digital computer model was used to simulate various concepts of groundwater flow near Wahweap Bay, Lake Powell. The filling of Lake Powell started in March 1963; and by 1983 the lake had risen almost 550 ft. This resulted in a maximum observed water level rise of 395 ft in a well in the Navajo Sandstone 1 mi from the lake. A steady-state model was prepared with subsurface recharge rates of 5,720 acre-ft/yr, 10,440 acre-ft/yr, and 14,820 acre-ft/yr, resulting in a range of hydraulic conductivity of 0.25 to 3.38 ft/da. Comparing measured and simulated water level changes resulted in a range of specific yield of 0.02 to 0.15. Using larger values for hydraulic conductivity in the model area corresponding to the axis of the Wahweap syncline and the Echo monocline was instrumental in attaining a reasonable match for the water level distribution. This supports previous concepts that areas where rocks are structurally deformed more readily transmit groundwater because of the higher degree of fracturing. Using the most likely simulation of the flow system, groundwater storage in the Navajo increased by about 25,000 acre ft/mi of shoreline form 1963-83, but the flow system will require about 400 yr to reach a state of equilibrium. (Author 's abstract)

  15. Investigation of exfoliation joints in Navajo sandstone at the Zion National Park and in granite at the Yosemite National Park by tectonofractographic techniques

    SciTech Connect

    Bahat, D.; Grossenbacher, K.; Karasaki, K.

    1995-04-01

    Tectonofractographic techniques have been applied to the study of joint exfoliation in the Navajo sandstone at Zion National Park and in the granite at Yosemite National Park. New types of fracture surface morphologies have been observed which enabled the discerning of incipient joints and consequent fracture growth in these rocks. Incipient jointing in the sandstone is mostly manifested by elliptical and circular fractures (meters to tens meters across) initiating from independent origins. They interfere with each other and grow to larger circular fractures producing exfoliation surfaces up to hundreds of meters across. Less frequently, series of large concentric undulations demonstrate the propagation of a large fracture front producing exfoliation from an individual origin. One such fracture front reveals refraction of undulations at a layer boundary. Certain en echelon fringes surround the joint mirror plane with well defined rims of en echelons and hackles which enable the determination of the tensile fracture stress, {sigma}f. Arches in Zion National Park are ubiquitous in shape and size, revealing stages in their evolution by a mechanical process, which was associated with exfoliation, but independent of local faulting. Exfoliation and arching mostly occurred on vertical surfaces of N-NNW and NE sets of prominent joints, but there are also deviations from this general trend. In Yosemite National Park large exfoliations (hundreds of meters in size) developed on the El Capitan cliff by the interaction and merging of many previous smaller incipient joints that vary in size from meters to tens of meter.

  16. Reconstruction and geochemical modelling of the diagenetic history of the middle Jurassic Oseberg sandstone reservoir, Oseberg Field, Norwegian North Sea

    SciTech Connect

    Girard, J.P.; Sanjuan, B.; Fouillac, C.

    1995-08-01

    A detailed multidisciplinary integrated study of the Middle Jurassic Oseberg reservoir in 13 wells of the Oseberg field, Norwegian North Sea, was carried out in order to (1) reconstruct precisely the timing, conditions and spatial variation of diagenetic transformations (2) characterize the nature and origin of the diagenetic fluids, and (3) develop a geochemical model of the observed diagenesis. The 20-60 in thick Oseberg Formation occurs at depths of 2.5 to 3.2 km, and at present temperatures ranging from 100 to 125{degrees}C. The detrital assemblage is mainly composed of quartz, K-feldspar, albrite, muscovite and lithic clay clasts, and is very homogeneous throughout the study area. The chronological sequence of diagenetic phases established from petrographic observations includes: minor siderite and pyrite, K-feldspar overgrowths, ankerite, feldspar dissolution, vermiform, kaolinite, quartz overgrowths, poikilotopic Fe-rich calcite, dickite. Diagenetic temperatures were determined from fluid inclusions in ankerite, quarts and calcite. Combination with modelled burial/thermal history permitted to constrain approximate ages and duration of major diagenetic events. Isotopic compositions of diagenetic cements indicate that meteoric water was (and still is) a major constituant of diagenetic fluids. Present formation waters are fairly similar chemically and isotopically at reservoir scale and represent mixing of three endmembers: seawater, meteoric water and primary evaporative brine. Stability diagrams and chemical geothermometers suggest that formation fluids are close to equilibrium with the host sandstone at present reservoir temperatures. Geochemical modelling of the diagenetic evolution of water-reservoir interactions was carried out using the EQ3/6 code and the Allan{sup TM}/Neptunix integrated simulator system. Results emphasize the importance of circulations of large volumes of fluid within the reservoir throughout the diagenetic history.

  17. Geologically-sensible modelling of the spatial distribution of permeability in eolian deposits: Page Sandstone (Jurassic), northern Arizona

    SciTech Connect

    Goggin, D.J.

    1988-01-01

    The spatial arrangement of permeability, one of the fundamental rock properties affecting fluid movement in petroleum reservoirs, is often poorly defined in current industry models. In addition, these models usually downplay many of the geological factors that contribute to the resulting spatial distribution of permeability in the interwell region of a productive interval. In a detailed study of outcrops of eolian (windblown) deposits, more than 10,000 localized permeability measurements were collected using a field minipermeameter on eleven different formations scattered over a six-state region of the midwestern and southwestern United States. Although most of these measurements were concentrated on a Page Sandstone (Jurassic) outcrop in Northern Arizona, the wide variety of sampling techniques applied in this study permitted the development of a generalized geostatistical model of the spatial arrangement of permeability in eolian deposits. Based on the knowledge of how bedding units and stratification types control the permeability distribution, a geologically-based, geostatistical permeability generation scheme was developed. This nested-kriging approach, the outer loop which handles the between-unit trends in permeability and the inner loop which handles the within-unit cross-bedding, accounts for the two geologic volume-scales of permeability variation present in the generalized geostatistical model. In order to establish the accuracy and reliability of the field permeameter used in this study, a careful theoretical and experimental analysis of the device response is made for a variety of field and laboratory applications. Two non-linear deviations associated with gas flow measurements of permeability in porous media are addressed.

  18. Degradation processes and consolidation of Late Jurassic sandstone dinosaur tracks in museum environment (Museum of Lourinhã, Portugal)

    NASA Astrophysics Data System (ADS)

    Leal, Sofia; mateus, Octavio; Tomas, Carla; Dionisio, Amelia

    2014-05-01

    The current study aims to conciliate conservation and restoration museology diagnosis with paleontological and geological curational needs and has, as subject of study, dinosaur footprints (vertebrates fossils). The footprints have been being exposed since 2004 in the paleontology hall of the Museum of Lourinhã, Portugal, and are part of a important paleontological collection of Late Jurassic vertebrate fossils from Lourinhã Formation. Presently, it is considered a unique heritage in danger of disappearing due to high decay level of disaggregation of its geological structure. The dinosaur footprints, (ML557) found, more precisely, on a coastline cliff in Lourinhã, Porto das Barcas, Lagido do Forno (coordinate 39° 14. 178'N, 9° 20. 397'W), Jurassic period, on the 5th of June 2001, by Jesper Milàn. This cliff of high slope presents sedimentary stratigraphic characteristics of a sandstone/siltstone of gray and red colors, by the '' Munsell scale and Color Chart''. Geological the tracks are Late Jurassic in age, and colected in the Lourinhã Formation, Praia Azul Member, of the Lusitanian Basin. There are three natural infills tridactyl tracks, possibly ascribed to ornithopod, a bipedal herbivore, resultant of a left foot movement, right and left. Footprints have 300-400mm of wide and 330-360mm of height with round fingers, which are elongated due to some degradation/erosion. In 2001, the footprints were collected from the field, cleaned, consolidated and glued in the laboratory of the Museum of Lourinhã before being exhibited in a museum display. Stone matrix was removed and a consolidation product applied, probably a polyvinyl acetate, of the brand Plexigum. The footprint with broken central digit was glued with an epoxy resin, Araldite. Both applied products were confirmed by analysis of µ-FTIR (Fourier Transform Infrared Spectroscopy) and both presented colour change and detachment surface problems. After collecting and storing, in 2004, footprints were transferred to the current public paleontology hall, ground floor, placed on the floor without any protection framework or environmental control (temperature and relative humidity). Presently, footprints show major geological structure disintegration/deterioration problems and were diagnosed several pathologies :"Blistering", "Powdering", "Exfoliation"' as well as "Dirt", "Fracture"', "Inscriptions", "Consolidates" and "Adhesives". Several laboratorial analysed were conducted to evaluate the presence of salts. Moreover a microclimatic study was conducted inside the museum to evaluate the influence of thermohygrometric parameters on the decay processes observed. As future procedures, all tracks will suffer a superficial cleaning (dust removal) with brush without any solvent and also the application of a consolidant aiming to restore some coehesion of these footprints. Since stone consolidation is a very risky intervention, several laboratory tests are being conducted with stone samples taken from the same layer and location from Porto das Barcas and using different commercial consolidation products.

  19. Provenance of Late Carboniferous to Jurassic sandstones for southern Taimyr, Arctic Russia: A comparison of heavy mineral analysis by optical and QEMSCAN methods

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaojing; Pease, Victoria; Omma, Jenny; Benedictus, Aukje

    2015-11-01

    Sandstone framework-grain petrography, optical and QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) heavy mineral analysis carried out on 40 samples collected from east and west southern Taimyr are used to constrain the provenance and tectonic history of Late Carboniferous to Late Jurassic siliciclastic sequences. The tectonic settings of provenance evolved gradually from a mix of volcanic arc and recycled orogen to craton interior. Much of the detritus in the Late Paleozoic to Mesozoic siliciclastic succession came from proximal sources with contributions from multi-type source rocks including acid igneous rocks, basalts, sedimentary rocks and low to medium-grade metamorphic rocks. Carboniferous to Permian sandstones contain low-diversity suites of heavy minerals, including apatite, tourmaline, zircon, rutile, Cr-spinel, monazite and titanite. Cr-spinel indicates probable influx from exposed ophiolitic basement. Abundant euhedral zircon and apatite suggest a volcanic arc source related with Uralian collision. The appearance of garnet in the early Triassic signals the unroofing of a metamorphic source. The abrupt increase of clinopyroxene in Middle to Late Triassic sandstones indicates the influx of detritus from basic rocks related with Siberian Trap magmatism. The decrease of Cr-spinel and an abundance of staurolite in Jurassic samples indicate that unroofing of an ophiolitic source ceased and that stripping of a different thrust sheet containing plenty of staurolite-bearing metamorphic rocks commenced.

  20. Periodic Spacing of Channel-Spanning Potholes in Navajo Sandstone, Henry Mountains Utah: Implications for Propagation of Incision Pulses across Tributary Junctions

    NASA Astrophysics Data System (ADS)

    Barnes, C. M.; Sklar, L. S.; Whipple, K. X.; Johnson, J. P.

    2004-12-01

    Incision of the Colorado River at Glen Canyon over the past ~1 Ma triggered pulses of incision that have migrated upstream through tributary drainages. The rate of incision of small tributaries often lags behind that of trunk streams, creatng over-steepened reaches at the tributary junction. In the arid Colorado Plateau, many of these low-order tributaries in massive lithologies have developed sequences of channel-spanning, periodically-spaced pothole bedforms. Although the dynamics of pothole formation and evolution are poorly understood, the occurrence of potholes correlates with super-critical flow and tools-limited conditions. We are exploring the hypothesis that pothole spacing and other profile attributes can be used to reconstruct the propagation of waves of incision through a drainage network. Here we report preliminary results of a field study of potholed reaches in steep, low-order channels draining Navajo Sandstone in the Henry Mountains, Utah. Our survey focused on channels where overlying sedimentary units and pediment deposits have largely been removed from the Navajo Sandstone. We surveyed six tributaries of the middle fork of Trail Canyon, and one tributary of Milk Creek, which are, in turn, minor tributaries of the Colorado River. We surveyed the long profile of each channel using a 5-m rod, 100-m tape, and a clinometer. In bedrock reaches, we focused on quantifying the spacing of alternating pothole steps and bedrock chutes, and the elevation change within and between potholes steps. We also characterized individual potholes by width, depth, maximum sediment size captured, and direction of flow recirculation. In alluviated reaches, we measured the bankfull width and depth to estimate relative differences in bankfull discharge. We also measured channel geometry in higher-order trunk streams at the junctions with the surveyed tributaries. Our preliminary results include the successful prediction of locations where potholed channels were found, by comparing topographic and geologic maps to estimate the character and quantity of coarse sediment supply. Where diorite pediments and overlying sedimentary rocks have been removed by erosion from above the Navajo Sandstone, pothole channels are common. Although the presence of grinders contributes to pothole abrasion, observations suggest that low supply rates of coarse sediment are essential for pothole development. Particularly important is low supply of the relatively hard diorite derived from the laccolithic cores of nearby Mt. Hillers and Mt. Holmes. In many potholes the only sediments present were sand-sized and finer. In each of the surveyed tributary channels we observed regular spacing of pothole bed forms. Preliminary analysis suggests a characteristic spacing of pothole steps that varies systematically with reach gradient, drainage area and other tributary attributes. Further analysis will allow us to explore the relationships between the morphology of potholed channels and the relative incision rates of the tributary and the trunk streams. It may be possible, for example, to assess the relative incisional efficiency of tributaries with differing extents of pothole development.

  1. Field guide to sedimentary structures in the Navajo and Entrada sandstones in southern Utah and northern Arizona: Chapter in Field-trip guidebook, 100th annual meeting, The Geological Society of America, Phoenix, Arizona, October 26-29, 1987

    USGS Publications Warehouse

    Rubin, David M.; Hunter, Ralph E.

    1987-01-01

    This field-trip guide describes the common sedimentary structures that occur in eolian sands. The outcrops that are described occur in the Navajo and Entiaia Sandstones between the areas of Page, Arizona and St. George, Utah (figure I), but the sedimentary structuresof these two sandstones are typical of most eolian deposits. The main part of the guide discusses the geologic setting and the origin of the various structures, and the road log discusses which structures are best displayed at selected outcrops.

  2. Bryce Canyon's Navajo Loop Trail

    USGS Multimedia Gallery

    Views along the Navajo Loop Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandston...

  3. Erosional remnants and adjacent unconformities along an eolian-marine boundary of the Page Sandstone and Carmel Formation, Middle Jurassic, south-central Utah

    SciTech Connect

    Jones, L.S.; Blakey, R.C. . Dept. of Geology)

    1993-09-01

    Sandstone ridges along the marine-eolian boundary of the Middle Jurassic Page Sandstone (eolian) with the lower Carmel Formation (restricted marine) in south-central Utah have been identified as erosional remnants consisting of strata of siliciclastic sabkha and eolian origin. The ridges lie within two distinct units of the Thousand Pockets Tongue of the Page. Two equally plausible models explain the genesis of these ridges. One model involves (1) early cementation of eolian and sabkha strata, (2) wind erosion leading to development of yardangs and unconformities, (3) yardang tilting due to evaporite dissolution, and (4) renewed deposition and burial. The alternative model explains ridge development through (1) subsidence, with tilting, of eolian and sabkha strata into evaporites due to loading from linear dunes, (2) evaporite dissolution and unconformity development, and (3) renewed deposition and burial. These models provide important clues about the nature of a missing part of the rock record. Reconstruction of units that were deposited but later eroded improves paleogeographic interpretation and here indicates that the Carmel paleo-shoreline was considerably farther to the northwest than previously believed.

  4. Diagenesis of Eolian and fluvial feldspathic sandstones, Norphlet formation (upper Jurassic), Rankin County, Mississippi, and Mobile County, Alabama

    SciTech Connect

    McBride, E.F.; Land, L.S.; Mack, L.E.

    1987-09-01

    Norphlet sandstones in seven cores from Mississippi and Alabama are arkoses and subarkoses deposited in eolian-dune, interdune, and fluvial environments. Similar to the deeply buried (> 5 km) Tertiary feldspathic sandstones of the Gulf basin, all detrital plagioclase that survived dissolution has been albitized. Fluvial red sandstone lost all initial porosity by the introduction of preburial pedogenic calcite and compaction. Initial porosity of eolian sands was reduced by compaction to an average of 29%; and later by cementation by quartz, carbonates, anhydrite, halite, K-feldspar, and illite. Quartz and anhydrite cements precipitated between 90/sup 0/ and 100/sup 0/C (approximately 2.3 km deep), carbonates and halite cements formed below 120/sup 0/C (< 3 km), and late-stage illite cement formed between 130/sup 0/ and 150/sup 0/C (4-5 km deep). Cements are patchy, and some, especially quartz and anhydrite, are texture-selective, being more abundant in coarser laminae. Secondary porosity, which makes up approximately half the porosity in thin sections, formed by dissolution of detrital grains (feldspar, rock fragments) and cements (anhydrite, carbonate, halite). Reservoir bitumen records an early phase of oil entrapment. Reservoir quality is influenced by the abundance of reservoir bitumen and thread-like illite, both of which bridge pores. Isotopic data suggest that during the first 30 to 40 m.y. of burial, subsurface diagenesis of the Norphlet Formation was dominated by deep-circulating, hot, meteoric water. This phenomenon may be characteristic of the early diagenetic history of rifted basins. 10 figures, 5 tables.

  5. Hoodoo on the Navajo Loop Trail

    USGS Multimedia Gallery

    Views along the Navajo Loop Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandston...

  6. Cedars on the Navajo Loop Trail

    USGS Multimedia Gallery

    Views along the Navajo Loop Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandston...

  7. Snow on the Navajo Loop Trail

    USGS Multimedia Gallery

    Views along the Navajo Loop Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandston...

  8. THE NAVAJOS.

    ERIC Educational Resources Information Center

    Navajo Tribe Public Relations and Information Dept., Window Rock, AZ.

    A STUDY OF NAVAJO AMERICAN INDIANS IS PRESENTED. INCLUDED ARE THE TRIBE'S HISTORY, RESOURCES, ECONOMIC SITUATION, AND WAYS TO IMPROVE IT. THE NAVAJOS ARE DIFFERENT FROM OTHER AMERICAN INDIAN TRIBES IN THAT THEY ARE RAPIDLY INCREASING, THEY HAVE INCREASED THE SIZE OF THEIR RESERVATION, THEY STILL LIVE IN ISOLATION AND IN A PRIMITIVE FASHION, AND…

  9. Triassic and Jurassic rocks at Currie, Nevada Preliminary paleontologic evidence

    SciTech Connect

    Johnson, E.A.; Dubiel, R.F.; Brouwers, E.M. ); Litwin, R.J. ); Ash, S.R. ); Good, S.C. )

    1993-04-01

    A sequence of continental rocks overlies the Lower Triassic Thaynes Formation in a poorly exposed syncline near Currie in northeastern NV. The authors recognize four lithostratigraphic units above the Thaynes near Currie and provide new paleontologic data. In ascending order, unit 1 (120 ft) consists of reddish-brown, very fine grained sandstone. Unit 2 (50 ft) consists of light-gray, trough cross-stratified, coarse-grained, conglomeratic sandstone. Unit 3 (at least 500 ft) consists of green, red, and brown sandstone and mudstone. Unit 4 occurs as isolated outcrops of reddish-orange, fine- to medium-grained sandstone. New fossil evidence, while not definitive, constrain the age of this sequence. Plant megafossils in unit 1 include (1) a specimen with narrow ovate leaves, possibly from an early Mesozoic conifer and (2) abundant fragments of probable Neocalamites. The presence of these fossils and the absence of any angiosperm leaves or wood fragments suggest an early Mesozoic age. Ostracodes in unit 3 are exclusively Darwinula sp., and their association with conchostracans in the absence of younger ostracodes suggests a Triassic age. Finally, two small outcrops, previously mapped as Triassic/Jurassic, contain the gastropods Pilidae indet. and Lymnaea sp., which resemble Late Cretaceous to Paleocene faunas. The sequence is similar to the nearest Lower Mesozoic section on the Colorado Plateau at Cove Fort, Utah, 165 miles to the southeast. The authors' new evidence supports the longstanding correlation of units 1--4 with the Lower Triassic Moenkopi Formation (part), the Shinarump and Petrified Forest Members of the Upper Triassic Chinle Formation, and the Lower Jurassic Navajo Sandstone of the Plateau. These rocks at Currie demonstrate that the Early Mesozoic depositional systems of the Colorado Plateau extended at least this far west and provide constraints on Early Mesozoic tectonism in the eastern Great Basin.

  10. Navajo Games.

    ERIC Educational Resources Information Center

    Cliff, Janet M.

    1990-01-01

    Reviews 163 sources on Navajo games, play, and toys. Includes an annotated bibliography of those materials. Examines relationships between games and religion, origin myths, and ceremonies. Discusses attitudes toward games, gambling, and cheating; and the dichotomy between children's and adults' games. Describes specific toys, games, and play…

  11. Two Bridges Formation on the Navajo Loop Trail

    USGS Multimedia Gallery

    Views along the Navajo Loop Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandston...

  12. Annual monsoon rains recorded by Jurassic dunes.

    PubMed

    Loope, D B; Rowe, C M; Joeckel, R M

    2001-07-01

    Pangaea, the largest landmass in the Earth's history, was nearly bisected by the Equator during the late Palaeozoic and early Mesozoic eras. Modelling experiments and stratigraphic studies have suggested that the supercontinent generated a monsoonal atmospheric circulation that led to extreme seasonality, but direct evidence for annual rainfall periodicity has been lacking. In the Mesozoic era, about 190 million years ago, thick deposits of wind-blown sand accumulated in dunes of a vast, low-latitude desert at Pangaea's western margin. These deposits are now situated in the southwestern USA. Here we analyse slump masses in the annual depositional cycles within these deposits, which have been described for some outcrops of the Navajo Sandstone. Twenty-four slumps, which were generated by heavy rainfall, appear within one interval representing 36 years of dune migration. We interpret the positions of 20 of these masses to indicate slumping during summer monsoon rains, with the other four having been the result of winter storms. The slumped lee faces of these Jurassic dunes therefore represent a prehistoric record of yearly rain events. PMID:11452305

  13. From Back-arc Drifting to Arc Accretion: the Late Jurassic-Early Cretaceous Evolution of the Guerrero Terrane Recorded by a Major Provenance Change in Sandstones from the Sierra de los Cuarzos, Central Mexico

    NASA Astrophysics Data System (ADS)

    Palacios Garcia, N. B.; Martini, M.

    2014-12-01

    The Guerrero terrane composed of Middle Jurassic-Early Cretaceous arc assemblages, were drifted from the North American continental mainland during lower Early Cretaceous spreading in the Arperos back arc basin, and subsequently accreted back to the continental margin in the late Aptian. Although the accretion of the Guerrero terrane represents one of the major tectonic processes that shaped the southern North American Pacific margin, the stratigraphic record related to such a regional event was not yet recognized in central Mexico. Due to the Sierra de los Cuarzos is located just 50 km east of the Guerrero terrane suture belt, its stratigraphic record should be highly sensitive to first order tectonic changes and would record a syn-tectonic deposits related to this major event. In that study area, were identified two main Upper Jurassic-Lower Cretaceous clastic units. The Sierra de los Cuarzos formation represents the lowermost exposed stratigraphic record. Sedimentary structures, sandstones composition, and U-Pb detrital zircon ages document that the Sierra de los Cuarzos formation reflects a vigorous mass wasting along the margin of the North American continental mainland, representing the eastern side of the Arperos back arc basin. Sandstones of the Sierra de los Cuarzos formation are free from detrital contributions related to the Guerrero terrane juvenile sources, indicating that the Arperos Basin acted like an efficient sedimentological barrier that inhibited the influence of the arc massifs on the continental mainland deposits. The Sierra de los Cuarzos formation is overlain by submarine slope deposits of the Pelones formation, which mark a sudden change in the depositional conditions. Provenance analysis documents that sandstones from the Pelones formation were fed by the mafic to intermediate arc assemblages of the Guerrero terrane, as well as by quartz-rich sources of the continental mainland, suggesting that, by the time of deposition of the Pelones formation, the Arperos Basin was closed and the Guerrero terrane was juxtaposed to the continental domain. Based on these data, we interpret the Pelones formation as the record of the major crustal reorganization in central Mexico related to the inversion of the Arperos back arc basin and accretion of the Guerrero terrane to the continental mainland.

  14. Architectural studies of Jurassic-Cretaceous fluvial units, Colorado Plateau

    SciTech Connect

    Miall, A.D.; Bromley, M.H.; Cowan, E.J.; Turner-Peterson, C.E.

    1989-03-01

    A sixfold hierarchy of architectural elements and bounding surfaces evolved from outcrop studies of three fluvial units: Westwater Canyon member (WCM), Morrison Formation, Upper Jurassic; Torrivio sandstone member (TSM), Gallup Sandstone, Upper Cretaceous, northwestern New Mexico; and Kayenta Formation (KF), Lower Jurassic, southwestern Colorado. This hierarchy is discussed.

  15. Eolian-fluvial interaction in the Page Sandstone (Middle Jurassic) in south-central Utah, USA a case study of erg-margin processes

    NASA Astrophysics Data System (ADS)

    Jones, Lawrence S.; Blakey, Ronald C.

    1997-03-01

    Channel- and lens-shaped deposits of non-eolian red sandstone are enclosed within the eolian Leche-e Member of the Page Sandstone in south-central Utah. Detailed analysis of lithology and geometry, and regional correlation of the red sandstone deposits suggests that the channel-shaped scours and in-filling deposits were formed by ephemeral stream processes, in contrast to earlier interpretations that suggested a marine estuarine origin. We hypothesize that ephemeral streams transporting volcanic debris flowed toward the north and northeast along the western edge of the Page erg. Local avulsion, possibly caused by eolian damming of an adjacent drainage, led to stream flow into low areas of the Page erg. Entrainment of loose eolian sand, combined with fluid loss via infiltration, led to a rapid increase in sediment/fluid ratio during flow events, initially resulting in sandy debris flow deposition. Subsequent floods entrained less material from the underlying, more cohesive, debris flow deposits, had a lower sediment/water ratio, and hence left deposits containing some evidence of flow turbulence. Eventually, stream drainage avulsed again, probably back to a more northerly course into the Carmel sea, fluvial deposition within the erg ceased, and eolian deposits covered the now intercalated fluvial complex.

  16. Navajo Electrification Demonstraiton Project

    SciTech Connect

    Larry Ahasteen, Project Manager

    2006-07-17

    This is a final technical report required by DOE for the Navajo Electrification Demonstration Program, This report covers the electric line extension project for Navajo families that currently without electric power.

  17. Strong Navajo Marriages

    ERIC Educational Resources Information Center

    Skogrand, Linda; Mueller, Mary Lou; Arrington, Rachel; LeBlanc, Heidi; Spotted Elk, Davina; Dayzie, Irene; Rosenbrand, Reva

    2008-01-01

    The purpose of this qualitative study, conducted in two Navajo Nation chapters, was to learn what makes Navajo marriages strong because no research has been done on this topic. Twenty-one Navajo couples (42 individuals) who felt they had strong marriages volunteered to participate in the study. Couples identified the following marital strengths:…

  18. The Navajo Language Program at Navajo Community College - Context and Collaboration.

    ERIC Educational Resources Information Center

    Slate, Clay; Pfeiffer, Anita

    Over the last 10 years, there has been considerable expansion of the Navajo Language Program at Navajo Community College (NCC). The guiding principle for this development has been that the seminal work be done by Navajos, in Navajo, for a Navajo audience, and for Navajo purposes. Navajos who speak Navajo have a richness of resource and an access

  19. Navajo Education and the Future.

    ERIC Educational Resources Information Center

    Roessel, Robert A., Jr.

    1999-01-01

    A veteran Navajo educator reflects on the War on Poverty's contributions to American Indian education and quality of life and offers his vision of the future: Navajo funding of educational programs that preserve their culture; a single system of schools replacing the Navajo reservation's overlapping systems; the Navajo Nation as 51st state; and

  20. Navajo-ABLE: Replication Model Navajo Assistive Technology Loan Program. Final Program Evaluation.

    ERIC Educational Resources Information Center

    Norton, Katie Jebb

    This final report discusses the activities and outcomes of the Navajo Assistive Bank of Loanable Equipment (Navajo-ABLE), a federally funded program designed to provide assistive technology (AT) devices, services, technical information, funding information, and training for Navajo children and youth with disabilities. The program was operated and

  1. NAVAJO ELECTRIFICATION DEMONSTRATION PROJECT

    SciTech Connect

    Terry W. Battiest

    2008-06-11

    The Navajo Electrification Demonstration Project (NEDP) is a multi-year project which addresses the electricity needs of the unserved and underserved Navajo Nation, the largest American Indian tribe in the United States. The program serves to cumulatively provide off-grid electricty for families living away from the electricty infrastructure, line extensions for unserved families living nearby (less than 1/2 mile away from) the electricity, and, under the current project called NEDP-4, the construction of a substation to increase the capacity and improve the quality of service into the central core region of the Navajo Nation.

  2. Marine Jurassic lithostratigraphy of Thailand

    NASA Astrophysics Data System (ADS)

    Meesook, A.; Grant-Mackie, J. A.

    Marine Jurassic rocks of Thailand are well-exposed in the Mae Sot and Umphang areas and less extensively near Mae Hong Son, Kanchanaburi, Chumphon and Nakhon Si Thammarat, in the north, west, and south respectively. They are generally underlain unconformably by Triassic and overlain by Quaternary strata. Based mainly on five measured sections, fourteen new lithostratigraphic units are established: (in ascending order) Pa Lan, Mai Hung and Kong Mu Formations of the Huai Pong Group in the Mae Hong Son area; Khun Huai, Doi Yot and Pha De Formations of the Hua Fai Group in the Mae Sot area; Klo Tho, Ta Sue Kho, Pu Khloe Khi and Lu Kloc Tu Formations of the Umphang Group in the Umphang area; and the Khao Lak Formation in the Chumphon area. Mudstone, siltstone, sandstone, limestone and marl are the dominant lithologies. Mudstones, siltstones and sandstones are widespread; limestones are confined to the Mae Sot, Umphang, Kanchanaburi and Mae Hong Son areas; marls are found only in Mae Sot. The sequences are approximately 900 m thick in Mae Sot and 450 m thick in Umphang and are rather thinner in the other areas, particularly in the south. Based on ammonites, with additional data from bivalves and foraminifera, the marine Jurassic is largely Toarcian-Aalenian plus some Bajocian. Late Jurassic ages given previously for strata in the Mae Sot and Umphang areas have not been confirmed.

  3. Contemporary Navajo Affairs: Navajo History Volume III, Part B.

    ERIC Educational Resources Information Center

    Eck, Norman K.

    Written specifically for Navajo junior high through college students, but also serving those interested in modern reservation developments and processs, the third volume of a curricular series on Navajo history provides a synthesis of data and pictorial records on current events in the areas of Navajo government, economic development, and health.

  4. Social Services: The Navajo Way.

    ERIC Educational Resources Information Center

    Belone, Cecilia; Gonzalez-Santin, Edwin; Gustavsson, Nora; MacEachron, Ann E.; Perry, Timothy

    2002-01-01

    Explores the Navajo Nation Division of Social Services' efforts to transform the Bureau of Indian Affairs service delivery paradigm into a more holistic case management paradigm for child and family services congruent with Navajo culture and rural location. Discusses a composite case to illustrate issues experienced by many Navajo clients.

  5. A Navajo Paradigm for Long Life Happiness--and for Reversing Navajo Language Shift.

    ERIC Educational Resources Information Center

    House, Deborah

    1997-01-01

    Describes a Navajo model by which individuals may assume responsibility for reversing Navajo language shift. Argues that reversing Navajo language shift requires that Navajos acknowledge the problem, that Navajo principles of balance and the natural order be applied to the problem, and that Navajo individuals and families make a commitment to

  6. Hydrogeology of the Mercosul aquifer system in the Paran and Chaco-Paran Basins, South America, and comparison with the Navajo-Nugget aquifer system, USA

    NASA Astrophysics Data System (ADS)

    Arjo, L. M.; Frana, A. B.; Potter, P. E.

    1999-06-01

    The giant Mercosul aquifer system consists of Triassic-Jurassic eolian-fluvio-lacustrine sandstones confined by Cretaceous basalt flows, and it covers about 1,195,500 km2 (461,583 miles2) in South America. The aquifer system encompasses all of the Paran Basin and part of the Chaco-Paran Basin and is one of the world's largest. The eolian Botucatu Sandstone and its equivalents form an important part of this system. Maps of structure, thickness of overlying rocks, and water temperature, and a potentiometric map, all based on 322 wells, define hydrogeologic characteristics and provide the basis for establishing guidelines for the long-term equilibrium use of this important multinational aquifer system. The Mercosul aquifer system is divided into two domains - the larger and better understood Paran Basin and the smaller and less well understood Chaco-Paran Basin. Most of the northern part of the Paran Basin has axially-directed groundwater flow, whereas the southern part of the aquifer discharges mostly to the southwest into the Corrientes Province of Argentina, with negligible discharge into the Atlantic Ocean. The Mercosul aquifer system is conservatively estimated to have been flushed at least 180 times since deposition. Various factors are responsible for this flushing, including appreciable rainfall since the end of the Cretaceous Period, probable uplift of the basins' borders in Late Cretaceous time, simple basin geometry, long-term riverine and groundwater flow to the southwest (ancestral and present Paran River Systems), and stable cratonic setting. Key hydraulic properties of the Mercosul aquifer system are compared to those of the eolian Jurassic Navajo-Nugget System of the western United States. The results demonstrate the importance of tectonics and climate on the evolution of sub-continental aquifer systems.

  7. Fault evolution in volcanic tuffs and quartz-rich eolian sandstone as mechanical analogs for faulting in Martian pyroclastic deposits

    NASA Astrophysics Data System (ADS)

    Okubo, C. H.

    2014-12-01

    In order to establish a foundation for studies of faulting in Martian rocks and soils in volcanic terrain, the distribution of brittle strain around faults within the North Menan Butte Tuff in the eastern Snake River Plain, Idaho and the Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah, has been recently described. These studies employed a combination of macroscopic and microscopic observations, including measurements of in situ permeability as a proxy for non-localized brittle deformation of the host rock. In areas where the tuff retained its primary granular nature at the time of deformation, initial plastic yielding in both tuffs occurred along deformation bands. Both compactional and dilational types of deformation bands were observed, and faulting occurred along clusters of deformation bands. Where secondary alteration processes imparted a massive texture to the tuff, brittle deformation was accommodated along fractures. Host-rock permeability exhibits little variation from non-deformed values in the North Menan Butte Tuff, whereas host rock permeability is reduced by roughly an order of magnitude through compaction alone (no alteration) in the Joe Lott Tuff. To create a bridge between these observations in tuff and the more substantial body of work centered on deformation band formation and faulting in quartz-rich sandstones, the same techniques employed in the North Menan Butte Tuff and the Joe Lott Tuff have also been applied to a kilometer-scale fault in the Jurassic Navajo Sandstone in the Waterpocket Fold, Utah. These observations demonstrate that the manifestation of strain and evolution of faulting in the Mars-analog tuffs are comparable to that in quartz-rich sandstones. Therefore, current understanding of brittle deformation in quartz-rich sandstones can be used to inform investigations into fault growth within porous tuffs on Mars. A discussion of these observations, practical limitations, and directions for future work are presented here.

  8. Sandstone Quarry

    USGS Multimedia Gallery

    A view of the Sandstone Quarry in Red Rock Canyon. Red Rock Canyon is a National Conservation Area managed by the Bureau of Land Management, located just outside of Las Vegas, Nevada. It is part of the Mojave Desert....

  9. Provenance of Norphlet sandstone, northern Gulf Coast

    SciTech Connect

    Ryan, W.P.; Ward, W.C.; Kuglar, R.L.

    1987-09-01

    The Upper Jurassic Norphlet sandstone of the northern Gulf Coast is predominantly subarkose, with some arkose in the eastern area and sublitharenite and quartzarenite in the western area. Despite great depths of burial and despite feldspar and rock-fragment constituents, diagenesis has not appreciably altered the composition of Norphlet sandstone. Therefore, reconstruction of original composition of Norphlet sandstone presented little difficulty. Variation in detrital modes of the Norphlet suggests compositionally distinct source terranes. Samples from Florida, Alabama, and Mississippi reflect the influence of metamorphic and plutonic rocks of the Appalachian Piedmont Province and of Triassic-Jurassic volcanic rocks. Sandstones in east Texas, northern Louisiana, and southern Arkansas were derived from sedimentary and metasedimentary rocks of the Ouachita system. The Arbuckle Mountains and Llano uplift may have supplied trace amounts of quartzo-feldspathic and volcanic-rock fragments to the extreme western part of the study area. Norphlet sandstones represent a mixture of collision-orogen-derived sediment from the Appalachian and/or Ouachita system and continental-block-derived sediment from paleohighs and uplifts within the Gulf basin. However, Norphlet sandstones plot in the craton-interior and transitional-continental fields on Q-F-L and QM-F-Lt tectonic-provenance diagrams, because of mineralogically mature source rocks, elimination of unstable grains by abrasion and sorting during deposition, and/or sediment mixing from different source terranes.

  10. So Many Kinds of Navajos.

    ERIC Educational Resources Information Center

    Underhill, Ruth

    Written for both American Indian and non-Indian school children, the purpose of this book is to present a picture of the varied ways of life on the Navajo Reservation in 1970. Facts relating to health, education, employment, and living conditions are presented from the viewpoint of Denny Lincoln, a 12 year old orphan who is placed in a Navajo

  11. The Navajos, A Critical Bibliography.

    ERIC Educational Resources Information Center

    Iverson, Peter

    Perhaps the most significant issue in the history of the Navajos is the tribe's success in maintaining its traditional culture while adapting to the massive pressures of Euramerican society. Few tribal groups have had to contend with as many and as diverse cultural and political competitors for as long a period of time as have the Navajos--Spain,

  12. Dinetah: Navajo History. Volume II.

    ERIC Educational Resources Information Center

    Roessel, Robert A., Jr.

    Using archaeological data, written chronicles of Spanish explorers and missionaries, and oral narratives and legends, the book traces the history of the Navajo people to their original homeland, Dinetah, located primarily off the present reservation in an area south and east of Farmington, New Mexico. The book discusses various theories on Navajo

  13. Navajo Nation Educational Hearings, 1975.

    ERIC Educational Resources Information Center

    Navajo Tribe, Window Rock, AZ.

    Part of an effort by the Navajo Division of Education to formulate a comprehensive educational plan, this document includes testimony by people representing the five agency divisions on the Reservation (Shiprock, Crownpoint, Chinle, Tuba City, and Fort Defiance) and the public school districts serving Navajos. Also included is a synthesis of the

  14. NAVAJO NATION HAZARDOUS WASTE SITES

    EPA Science Inventory

    This point coverage represents the locations of hazardous waste sites on the Navajo Nation Indian Reservation. The point locations were delineated on 1:24,000 scale US Geological Survey (USGS) topographic maps by staff from the Navajo Nation EPA, Resource Conservation & Reco...

  15. Navajo Education, 1948-1978: Its Progress and Its Problems. Volume III, Part A, Navajo History.

    ERIC Educational Resources Information Center

    Roessel, Robert A., Jr.

    One in a continuing series on Navajo history and culture, this volume presents extensive information about Navajo education from 1948 through 1978 and analyzes that information from a Navajo viewpoint with the purpose of promoting quality education directed and controlled by Navajo people. Following a brief introduction to the series and to Navajo

  16. Sandstone Cliffs

    USGS Multimedia Gallery

    Views along the Queen's Garden Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sands...

  17. Navajo Coal: Demands, Attitudes, and Environment.

    ERIC Educational Resources Information Center

    Goodman, James M.

    The operation of several coal mines with vast proven reserves on the Navajo reservation is a manifestation of conflict between: a power hungry external world; the preservationist attitudes of traditional Navajo culture; the disadvantaged socio-economic status of the average Navajo wage earner; and the Navajo Nation's long term needs for internal

  18. To Be A Navajo. Second Edition, 1976.

    ERIC Educational Resources Information Center

    Begay, Shirley M., Ed.

    Designed to provide culturally relevant and interesting reading material in Navajo for Navajo speaking children, this booklet presents 20 short stories written and illustrated by students at Rough Rock Demonstration School. Intended to encourage Navajo speaking children, and others, to read and to instill pride in being a Navajo, the stories…

  19. A History of Navajo Clans. First Edition.

    ERIC Educational Resources Information Center

    Lynch, Regina H.; And Others

    Pen and ink drawings illustrate characterizations of 29 Navajo clans in this book, which is intended to acquaint young Navajo people and others with Navajo history and culture. The introduction discusses the significance of the Navajo clan system and the relationship among family bonds, self-esteem, and cultural values. The illustrated text tells

  20. Jurassic Paleolatitudes, Paleogeography, and Climate Transitions In the Mexican Subcontinen

    NASA Astrophysics Data System (ADS)

    Molina-Garza, R. S.; Geissman, J. W.; Lawton, T. F.

    2014-12-01

    Jurassic northward migration of Mexico, trailing the North America plate, resulted in temporal evolution of climate-sensitive depositional environments. Lower-Middle Jurassic rocks in central Mexico contain a record of warm-humid conditions, which are indicated by coal and compositionally mature sandstone deposited in continental environments. Preliminary paleomagnetic data indicate that these rocks were deposited at near-equatorial paleolatitudes. The Middle Jurassic (ca. 170 Ma) Diquiyú volcanic sequence in central Oaxaca give an overall mean of D=82.2º/ I= +4.1º (n=10; k=17.3, α95=12º). In the Late Jurassic, the Gulf of Mexico formed as a subsidiary basin of the Atlantic Ocean, when the supercontinent Pangaea ruptured. Upper Jurassic strata, including eolianite and widespread evaporite deposits, across Mexico indicate dry-arid conditions. Available paleomagnetic data (compaction-corrected) from eolianites in northeast Mexico indicate deposition at ~15-20ºN. As North America moved northward during Jurassic opening of the Atlantic, different latitudinal regions experienced coeval Late Jurassic climatic shifts. Climate transitions have been widely recognized in the Colorado plateau region. The plateau left the horse-latitudes in the late Middle Jurassic to reach temperate humid climates at ~40ºN in the latest Jurassic. In turn, the southern end of the North America plate (central Mexico) reached arid horse-latitudes in the Late Jurassic. At that time, epeiric platforms developed in the circum-Gulf region after a long period of margin extension. We suggest that Upper Jurassic hydrocarbon source rocks in the circum-Gulf region accumulated on these platforms as warm epeiric hypersaline seas and the Gulf of Mexico itself were fertilized by an influx of wind-blown silt from continental regions. Additional nutrients were brought to shallow zones of photosynthesis by ocean upwelling driven by changes in the continental landmass configuration.

  1. Jurassic petroleum trends in eastern Gulf Coastal Plain and central and eastern Gulf of Mexico

    SciTech Connect

    Mancini, E.A.; Mink, R.M.; Bearden, B.L.

    1986-05-01

    Three Jurassic petroleum trends can be delineated in Mississippi, Alabama, and Florida, and in the central and eastern Gulf of Mexico. These trends are recognized by characteristic petroleum traps, reservoirs, and hydrocarbon types. The source for the Jurassic hydrocarbons is Smackover algal mudstones. The Jurassic oil trend includes the area north of the regional peripheral fault systems in the tri-state area, and extends into the area north of the Destin anticline. Traps are basement highs and salt anticlines, with Smackover grainstones and dolostones and Norphlet marine, eolian, and wadi sandstones as reservoirs. This trend has potential for Jurassic oil accumulations in the eastern Gulf of Mexico. The Jurassic oil and gas-condensate trend includes the onshore area between the regional peripheral fault systems and Wiggins arch and extends into the area of the Destin anticline. Traps are basement highs, salt related anticlines, and extensional faults. Cotton Valley fluvial-deltaic sandstones, Haynesville carbonates and fluvial-deltaic sandstones, Smackover grainstones, packstones, dolostones, and marine sandstones, and Norphlet marine, eolian, and wadi sandstones serve as reservoirs. This trend contains most of the Jurassic fields in the eastern Gulf coastal plain. The trend has high potential for significant petroleum accumulations in the eastern Gulf of Mexico. The Jurassic deep natural gas trend includes the onshore area south of the Wiggins arch and extends into the Mississippi-Alabama shelf. Traps are faulted salt anticlines with basement highs as potential traps. Cotton Valley deltaic-strandplain sandstones and Norphlet eolian sandstones are the reservoirs. Several gas discoveries below 20,000 ft have been made in this trend in Mississippi and offshore Alabama. The trend has excellent potential for major gas accumulations in coastal Alabama and central Gulf of Mexico.

  2. Situational Navajo: A School-Based, Verb-Centered Way of Teaching Navajo.

    ERIC Educational Resources Information Center

    Holm, Wayne; Silentman, Irene; Wallace, Laura

    This paper describes situational Navajo language immersion programs, explaining that situational classrooms recreate a situation in which students need Navajo to communicate and noting that Navajo is a very verb centered language. Situational Navajo takes many of the recurring situations in the school and family setting and makes them the core of

  3. Porosity prediction in sandstones using erosional unconformities

    SciTech Connect

    Shanmugam, G.

    1989-03-01

    Erosional unconformities of subaerial origin are created by tectonic uplifts and eustatic sea level fall. Most erosional unconformities developed on sandstones are planes of increased porosity because uplifted sandstones are exposed to undersaturated CO/sub 2/-charged meteoric waters that result in dissolution of unstable framework grains and cements. The chemical weathering of sandstones is intensified in humid regions by the heavy rainfall, soil zones, lush vegetation, and accompanying voluminous production of organic and inorganic acids. Erosional unconformities are considered hydrologically open systems because of abundant supply of fresh meteoric water and relatively unrestricted transport of dissolved constituents away from the site of dissolution, causing a net gain in porosity near unconformities. Thus, porosity in sandstones tends to increase toward overlying unconformities. Such porosity trends have been observed in hydrocarbon-bearing sandstone reservoirs in Alaska, Algeria, Australia, China, Libya, Netherlands, Norwegian North Sea, Norwegian Sea, and Texas. A common attribute of these reservoirs is that they were all subaerially exposed under heavy rainfall conditions. An empirical model has been developed for the Triassic and Jurassic sandstone reservoirs in the Norwegian North Sea on the basis of the observed relationship that shows an increase in porosity in these reservoirs with increasing proximity to the overlying base of Cretaceous unconformity. An important practical attribute of this model is that it allows for the prediction of porosity in the neighboring undrilled areas by recognizing the base of Cretaceous unconformity in seismic reflection profiles and by constructing subcrop maps.

  4. A Jurassic Shock-Aftershock Earthquake Sequence Recorded by Small Clastic Pipes and Dikes within Dune Cross-Strata, Zion National Park, Utah

    NASA Astrophysics Data System (ADS)

    Loope, D. B.; Zlotnik, V. A.; Kettler, R. M.; Pederson, D. T.

    2012-12-01

    Eolian sandstones of south-central and southeast Utah contain large volumes of contorted cross-strata that have long been recognized as products of liquefaction caused by seismic shaking. Unlike most sites where Navajo Sandstone is exposed, in Zion National Park (southwestern Utah), the Navajo contains very, very few contorted strata. We have, however, mapped the distribution of more than 1,000 small-scale, vertical pipes and dikes in uncontorted cross-strata of the Navajo at two small study sites in Zion. Pipes are 2-5 cm in diameter and up to 3 m long; dikes are ~6 cm wide. Clusters of the water-escape structures lie directly above and below numerous, near-horizontal bounding surfaces. Dikes are restricted to the wind-ripple strata that lie above the bounding surfaces. Pipes are common both above and below the bounding surfaces. In map view, most pipes are arranged in lines. Near the bounding surfaces, pipes merge upward with shallow dikes trending parallel to the lines of pipes. Pipes formed in grainflows—homogeneous, well-sorted sand lacking cohesion. Dikes formed above the bounding surface, in more-cohesive, poorly sorted, wind-ripple strata. As liquefaction began, expansion of subsurface sand caused spreading within the unliquified (capping) beds near the land surface. Dikes intruded cracks in the wind-ripple strata, and pipes rose from the better-sorted sand to interdune surfaces, following trends of cracks. Because the wind-ripple strata had low cohesive strength, a depression formed around each rupture, and ejected sand built upward to a flat-topped surface rather than forming the cone of a classic sand volcano. In one 3 m2 portion of the map area, a cluster of about 20 pipes and dikes, many with truncated tops, record eight stratigraphically distinct seismic events. The large dunes that deposited the Navajo cross-strata likely moved ~1m/yr. When, in response to seismic shaking, a few liters of fluidized sand erupted onto the lowermost portion of the dune lee slope through a pipe, the erupted sand dried and was buried by climbing wind-ripple strata as the large dune continued to advance downwind. The mapped cluster recording eight distinct seismic events lies within thin-laminated sediment that was deposited by wind ripples during 1 m (~ 1 year) of southeastward dune migration. We conclude that the small pipes and dikes of our study sites are products of numerous >MM 5 earthquakes, some of which recurred at intervals of less than 2 months. We interpret one small cluster of pipes and dikes with well-defined upward terminations as a distinct shock-aftershock sequence. Because the largest modern earthquakes can produce surface liquefaction only up to about 175 km from their epicenters, the Jurassic epicenters must have been well within that distance. The tendency of modern plate boundaries to produce high-frequency aftershocks suggests that the epicenter for this Jurassic sequence lay to the southwest, within the plate boundary zone (not within continental rocks to the east). As eolian dunes steadily migrate over interdune surfaces underlain by water-saturated dune cross-strata, the thin, distinct laminae produced by the wind ripples that occupy dune toes can faithfully record high-frequency seismic events.

  5. Navajo Pawn: A Misunderstood Traditional Trading Practice

    ERIC Educational Resources Information Center

    Kiser, William S.

    2012-01-01

    Navajo trading has been a crucial component of that tribe's localized economy for generations and has been the subject of much scholarship over the years. The role of the Navajo trader in influencing the types and styles of crafts that Navajos created as well as providing tribal members with an outlet for those items remains important to their

  6. Navajo History: The Land and the People.

    ERIC Educational Resources Information Center

    Acrey, Bill P.

    This textbook for high school, college, or adult readers covers the history and culture of the Navajo People from their own perspective from the coming of American control in 1846 until 1978. Topics include the last Navajo war, the Long Walk, the impact of Navajo agents on policy, early traders and flourishing of crafts, settlement of reservation…

  7. Heterogeneity of eolian sandstones and enhanced oil recovery

    SciTech Connect

    Schenk, C.J.; Krystinik, L.F. )

    1989-09-01

    Eolian sandstones constitute a heterogeneous group of hydrocarbon reservoirs because of significant variations in sedimentology, diagenesis, and structural setting. Simple eolian reservoirs are associated with stratigraphic traps and generally produce from eolian-dune sandstones with preserved topographic relief. The main forms of heterogeneity in simple reservoirs are the stacking of stratification types (ripple, sandflow, and grainfall strata) and diagenetic variations within the eolian-dune sandstone. Simple reservoirs pose little difficulty to secondary and tertiary recovery technologies, provided directional permeabilities and fluid-flow pathways are known from careful analysis of core, dipmeter data, porosity logs, and, if possible, outcrop studies. Examples of simple eolian reservoirs are the Permian upper part of the Minnelusa Formation, Powder River basin, Wyoming, and the Jurassic Entrada Sandstone, San Juan basin, New Mexico. Complex eolian reservoirs are generally associated with structural traps where productive eolian-dune sandstones are intercalated with nonproductive sabkha, sand-sheet, or fluvial deposits, resulting in strongly layered reservoir behavior with respect to fluid flow and difficulties for EOR application. Heterogeneity in complex reservoirs is also caused by stratification types, diagenesis, and fractures in some reservoirs. Examples of complex eolian reservoirs include the Pennsylvanian-Permian Tensleep and Weber Sandstones of Wyoming and Colorado and the Jurassic Nugget Sandstone of Utah and Wyoming.

  8. Social services: the Navajo way.

    PubMed

    Belone, Cecilia; Gonzalez-Santin, Edwin; Gustavsson, Nora; MacEachron, Ann E; Perry, Timothy

    2002-01-01

    The development of child welfare services in Indian Country followed enactment of the 1975 Indian Education and Self-Determination Act and the 1978 Indian Child Welfare Act. These acts allow tribal contracting with the Bureau of Indian Affairs (BIA) to provide social services. Because the BIA model has not fit well with Navajo needs, the Navajo Nation Division of Social Services is creating a more holistic case management paradigm for child and family services, which is more congruent with its culture and its rural, sparsely populated land. PMID:12380626

  9. Tough Issues for Navajo Youth and Navajo Schools. Draft.

    ERIC Educational Resources Information Center

    Trotter, Robert T., II; And Others

    In 1990, the Native American Prevention Project of AIDS and Substance Abuse began to develop, implement, and evaluate culturally sensitive in-school prevention programs for Navajo youth and their families. This project paper combines ethnographic interviews and observations with baseline quantitative data collection. A baseline survey of 174 9th-

  10. Language Shift among the Navajos: Identity Politics and Cultural Continuity.

    ERIC Educational Resources Information Center

    House, Deborah

    Despite public discourse affirming the importance of maintaining the Navajo language and despite extensive language maintenance efforts by Navajo schools, the Navajo people are experiencing a rapid shift from Navajo to English. This book draws on fieldwork conducted in the small community of Tsaile, on the Navajo Reservation in northeastern

  11. EDUCATIONAL ACHIEVEMENT AND THE NAVAJO.

    ERIC Educational Resources Information Center

    HAAS, JOHN; MELVILLE, ROBERT

    A STUDY WAS DEVISED TO APPRAISE THE ACADEMIC ACHIEVEMENT OF NAVAJO STUDENTS LIVING IN DORMITORIES AWAY FROM THE INDIAN RESERVATION. THE FOLLOWING SEVEN FACTORS WERE CHOSEN TO BE INVESTIGATED AS BEING DIRECTLY RELATED TO ACHIEVEMENT--(1) INTELLIGENCE, (2) READING ABILITY, (3) ANXIETY, (4) SELF-CONCEPT, (5) MOTIVATION, (6) VERBAL DEVELOPMENT, (7)

  12. The Navajo Social Studies Project.

    ERIC Educational Resources Information Center

    Cata, Juanita

    The philosophy undergirding a social studies program developed for the BIA by the University of New Mexico is discussed to aid the teacher in helping Navajo children view with insight their own unique culture and the cultures about them. A beginning or pre-school teaching unit ("When I Come to School") dealing with easily mastered classroom…

  13. Memo to Navajo Community Schools.

    ERIC Educational Resources Information Center

    Lee, George P.

    This handbook contains general resource information for program planning in Navajo education. Contained are listings on: 1) Key Questions; 2) Community Education and Local Control; 3) Education Laboratories; 4) Steps in Starting A Community College; 5) Recommended Books; 6) Bibliography of Instructional Resources; 7) Program Planning and Proposal…

  14. Navajos and National Nuclear Policy.

    ERIC Educational Resources Information Center

    Barry, Tom

    1979-01-01

    Describes the history of nuclear development in New Mexico, notes the cumulative detrimental effect on the Navajo Nation, and emphasizes federal inaction regarding health and safety standards and regulation in the nuclear power industry. Journal availability: see RC 503 522. (SB)

  15. Traditional Navajo Maps and Wayfinding

    ERIC Educational Resources Information Center

    Francis, Harris; Kelley, Klara

    2005-01-01

    An example of the way finding process when using verbal and other traditional maps among the Navajo Indians of the southwestern United States is presented. The scholarly literature on the Southwest offers examples of verbal maps that construct both linear space, such as trails, and broad geographical space, including hunting territories and large

  16. Traditional Navajo Maps and Wayfinding

    ERIC Educational Resources Information Center

    Francis, Harris; Kelley, Klara

    2005-01-01

    An example of the way finding process when using verbal and other traditional maps among the Navajo Indians of the southwestern United States is presented. The scholarly literature on the Southwest offers examples of verbal maps that construct both linear space, such as trails, and broad geographical space, including hunting territories and large…

  17. Traders on the Navajo Reservation. A Report on the Economic Bondage of the Navajo People.

    ERIC Educational Resources Information Center

    Southwestern Indian Development, Inc., Window Rock, AZ.

    Conducted in 1969 by 8 Navajo students, this study investigates the Anglo trader in terms of his socioeconomic influence on the American Indians of the Navajo Reservation. Limited to 30 randomly selected trading posts located in the central and eastern portions of the Navajo Reservation, this study reflects findings derived from personal

  18. Petrophysical Properties of Sandstones Containing Deformation Bands Versus Those With Fractures: the Importance of Grain Contact Strength to Fault-Zone Structure

    NASA Astrophysics Data System (ADS)

    Schneider, J. R.; Tobin, H. J.; Goodwin, L. B.

    2010-12-01

    In upper crustal fault zones, the majority of slip accumulates within a fault core, which is surrounded by a less deformed damage zone. Both the width and structural character of the damage zone affect its mechanical and hydrologic properties. Fault-related deformation can change rock mechanical properties, causing stress orientations to rotate in fault damage zones, and affecting seismicity over time. In addition, the types, densities, and orientations of structures in fault zones exert a first-order control on fault-zone permeability structure, permeability anisotropy, and flow pathways. For example, open-fracture damage zones enhance fault-parallel flow, whereas cataclastic deformation band networks slow flow in every direction except parallel to the line of intersection between bands. To improve our understanding of controls on damage zone character, we explored relationships between fault-zone structure and lithologic characteristics such as porosity and cement mineralogy in faulted quartz-rich sandstones. The sandstones chosen from fault sites in the Jurassic Navajo and Entrada sandstones in Utah, and the Cretaceous Mesaverde sandstone in Wyoming, exhibit a wide range in porosity. Samples collected include even greater variability in cements, from clay coatings on grains to patchy carbonate cement to grain-bridging quartz overgrowths and iron oxide cements. These variables demonstrably influence damage zone character, resulting in fractures in some locations and deformation bands in others (even within a single fault zone) and affecting deformation-band damage zone width. They likely influenced grain-contact strength also. Because ultrasonic velocity and related elastic moduli also vary with grain-contact strength, we measured P and S wave velocities as a function of confining pressure to 20 MPa as a sensitive proxy for grain-contact strength. More than 40 samples, including both host rock and rock with deformation bands, have been analyzed. Samples containing deformation bands display different ultrasonic velocities than adjacent samples lacking deformation bands. These data are used to evaluate the relative importance of the variables affecting deformation in clastic rocks. Establishing a quantitative link between fault structures, cements, porosity, and lithology and ultrasonic velocity will ultimately allow results to be directly applied to borehole geophysics and seismic reflection studies to improve prediction of fault-zone characteristics and fluid flow properties in quartz-rich sandstone reservoirs.

  19. Geohydrology and effects of water use in the Black Mesa area, Navajo and Hopi Indian Reservations, Arizona

    USGS Publications Warehouse

    Eychaner, James H.

    1983-01-01

    The N aquifer is the main source of water in the 5,400-square-mile Black Mesa area in the Navajo and Hopi Indian Reservations in northeastern Arizona. The N aquifer consists of the Navajo Sandstone and parts of the underlying Kayenta Formation and Wingate Sandstone of Jurassic and Triassic age. Maximum saturated thickness of the aquifer is about 1,050 feet in the northwestern part of the area, and the aquifer thins to extinction to the southeast. Water is under confined conditions in the central 3,300 square miles of the area. To the east, north, and west of Black Mesa, the aquifer is exposed at the surface, and water is unconfined. The aquifer was in equilibrium before about 1965. Recharge of about 13,000 acre-feet per year was balanced primarily by discharge near Moenkopi Wash and Laguna Creek and by evapotranspiration. At least 180 million acre-feet of water was in storage. The estimated average hydraulic conductivity of the aquifer is 0.65 foot per day. The confined storage coefficient is estimated to be about 0.0004 where the aquifer is thickest, and the estimated unconfined storage coefficient ranges from 0.10 to 0.15. Ground-water withdrawals that averaged 5,300 acre-feet per year from 1976 to 1979 have caused water levels to decline in wells in the confined part of the aquifer. Withdrawals include an average of 3,700 acre-feet per year to supply a coal-slurry pipeline from a coal mine on Black Mesa. Six observation wells equipped with water-level recorders have been used to monitor aquifer response. The water level in one well 32 miles south of the mine declined 17 feet from 1972 through 1979 and 3.5 feet during 1979. A mathematical model of the N aquifer was developed and calibrated for equilibrium and nonequilibrium conditions. The model was used in part to improve estimates of aquifer characteristics and the water budget, and it successfully reproduced the observed response of the aquifer through 1979. The model results indicate that about 95 percent of the 44,000 acre-feet of water pumped from 1965 to 1979 was withdrawn from storage, but the reduction amounted to less than 0.03 percent of total storage. Water-level declines through 1979 were estimated to be more than 100 feet in an area of 200 square miles. Four projections of future water-level changes were made using the model. The most probable projection indicates that water-level declines would exceed 100 feet in an area of 440 square miles by 2001. Most of the decline would be recovered within a few years if withdrawals at the mine ceased. By 1990, however, municipal-supply pumpage is expected to exceed pumpage at the mine, and this pumpage would continue to have significant impacts on water levels in the Black Mesa area.

  20. "1970" Inter-Agency Health Meeting (Navajo).

    ERIC Educational Resources Information Center

    Arizona Commission of Indian Affairs, Phoenix.

    An inter-agency health meeting regarding health services for Navajo Indians is reported on in this document. The meeting, sponsored by the Arizona Commission of Indian Affairs, involved agencies such as the U.S. Public Health Service, Bureau of Indian Affairs, and the Navajo Tribe. Included in the proceedings are reports and remarks by…

  1. Defining Student Success through Navajo Perspectives

    ERIC Educational Resources Information Center

    Bowman, Colleen Wilma

    2013-01-01

    The purpose of this qualitative study was to determine the definition of student success as defined by the Navajo people. The data collection method used was the focus group. The data were collected from two geographical settings from two public schools located within the boundaries of the Navajo Indian Reservation. The focus group participants…

  2. Navajo Art--A Way of Life.

    ERIC Educational Resources Information Center

    Clover, Faith

    This curriculum unit on Navajo art consists of three lessons, each of which can stand alone or be used in conjunction with the others. Teacher and students will explore Navajo traditions in the unit and use the insight gained to create artworks that connect people to their community and natural environment. The key artworks provide the foundation

  3. Classroom Management in a Navajo Middle School

    ERIC Educational Resources Information Center

    McCarthy, Jane; Benally, Joe

    2003-01-01

    Classroom management presents a serious challenge in most schools, but especially in schools on a Navajo Reservation that have been traditionally academically low-performing schools. There appears to be a mismatch between the attitudes, skills, and behaviors Navajo children bring with them to school and the expectations schools have for their

  4. Defining Student Success through Navajo Perspectives

    ERIC Educational Resources Information Center

    Bowman, Colleen Wilma

    2013-01-01

    The purpose of this qualitative study was to determine the definition of student success as defined by the Navajo people. The data collection method used was the focus group. The data were collected from two geographical settings from two public schools located within the boundaries of the Navajo Indian Reservation. The focus group participants

  5. Sovereignty: The Navajo Nation and Taxation.

    ERIC Educational Resources Information Center

    Benson, Michael

    Contending that it is wrong for the Navajo Government to continue to neglect its citizens by not implementing a taxation program, this monograph is written to generate interest in and discussion of a taxation program and the Navajo Tax Commission, created in 1974. Specifically, this booklet presents basic information re: the financing of the…

  6. Navajo generating plant and Grand Canyon haze

    SciTech Connect

    Norris, J.E.

    1991-01-15

    This article examines the question of whether the Navajo generating plant pollution is contributing to pollution of the air in the Grand Canyon region. The topics include the regulatory context of the plant, the experiment known as the Winter Haze Intensive Tracer Experiment (WHITEX), the National Research Council evaluation of the WHITEX, and The Navajo Generating Station Visibility Study.

  7. An Ethnography of the Navajo Reproductive Cycle.

    ERIC Educational Resources Information Center

    Wright, Anne

    1982-01-01

    Describes the reproductive cycle (menarche, menstrual cycle, fertility and contraceptive use, and menopause) as experienced by two groups of contemporary Navajo women. Eighty Navajo women, 40 traditional and 40 acculturated, participated in the 1978 research project which focused on influences of menopause. (ERB)

  8. Navajo Educational Values and Facility Design.

    ERIC Educational Resources Information Center

    Dore, Christopher D.

    The Bilingual Education Act of 1968 and the Indian Education Act of 1972 have brought Navajo education into a new period, characterized by a return to a more traditional curriculum, within the parameters of the bicultural life ways of the contemporary Navajo. This document addresses the issue of designing educational facilities that contribute

  9. Entrepreneurship and Economic Development: The Navajo Model.

    ERIC Educational Resources Information Center

    Devlin, J. Stuart; Carlin, William B.

    The Navajo Nation, in the summer of 1987, sponsored the Special Pre-Business Introduction for Navajo Students (SPINS) program through the business colleges at three universities: (1) University of Arizona; (2) University of New Mexico; and (3) New Mexico State University. SPINS provided entrepreneurial training, through entrepreneurship workshops,

  10. Navajo History to 1846: The Land and the People.

    ERIC Educational Resources Information Center

    Acrey, Bill P.

    This textbook for high school, college, or adult readers covers major areas of Navajo history from prehistoric times to 1846 from the Navajo point of view. A brief description of pre-Navajo cultures including the Hohokam, Mogollon, and Anasazi precedes the more detailed history of the arrival of the Navajo and contact with the Pueblo peoples.…

  11. The Anglo Revolution in New Mexico: The Navajo Mine.

    ERIC Educational Resources Information Center

    Simpson, Thomas K.

    1979-01-01

    The "Navajo Mine" is a section of the Navajo Reservation in New Mexico containing highly valuable coal deposits to which the Navajo have in fact given up their title through long-term lease agreements with an Anglo corporation. This article applies the idea of the "Anglo" revolution to the Navajo Mine. (NQ)

  12. Some Remarks on Navajo Geometry and Piagetian Genetic Theory.

    ERIC Educational Resources Information Center

    Pinxten, Rik

    1991-01-01

    Examines aspects of Navajo cosmology relevant to understanding Navajo spatial representations. Compares Navajo children's spatial knowledge with Piaget's findings about the development of geometric concepts in Swiss children. Describes classroom activities whereby Navajo children explore the geometry inherent in their cultural and physical…

  13. When Navajos Had Too Many Sheep: the 1940's.

    ERIC Educational Resources Information Center

    Boyce, George A.

    The book is the story of the Navajos during the decade of forced stock reduction on the Navajo Reservation. This decade was marked by confusion, frustration, and bitterness on the part of the Navajo Nation. It is of the 1940's, during which the Navajos faced their greatest crisis since their removal to military confinement from 1864 to 1868, that

  14. Family Planning Attitudes of Traditional and Acculturated Navajo Indians.

    ERIC Educational Resources Information Center

    Ackerman, Alan; And Others

    To determine whether various indices of "acculturation" would predict attitudes towards family planning was the major purpose of a survey conducted among a highly educated group of Navajo people at Navajo Community College (NCC). Owned and operated by the Navajo Tribe, NCC served as a target survey model due to its 90% population of Navajo

  15. Microstructural analysis of quartz grains in Vasyugan suite sandstones of layer Ui1-21 in Kazanskoe deposit

    NASA Astrophysics Data System (ADS)

    Cherdantseva, D.; Krasnoshchekova, L.

    2014-08-01

    Microstructural analysis of quartz grains in sandstones revealed preferred directions which define and influence porosity and permeability anisotropy in oil and gas reservoirs In this research, we investigated the Upper Jurassic sandstone reservoir sediments from 14 wells in Kazanskoe field. The authors studied: the orientation of elongated quartz grains, and intergranular fracture within grains, as well as the pore space in oriented thin sections of sandstones. The analysis of elongated quartz grains in the bedding plane showed three main types of preferred directions in quartz grain orientation along different axes in sandstone reservoirs. Obtained results allow identifying a variability of facies and dynamic depositional environment for Upper Jurassic sandstone formation. Subsequently, these results can be used in field modeling, as well as pattern optimization of injection and production wells.

  16. Final Report - Navajo Electrification Demonstration Project - FY2004

    SciTech Connect

    Kenneth L. Craig, Interim General Manager

    2007-03-31

    The Navajo Electrification Demonstration Project (NEDP) is a multi-year projects which addresses the needs of unserved Navajo Nation residents without basic electricity services. The Navajo Nation is the United States' largest tribe, in terms of population and land. An estimated 18,000 Navajo Nation homes do not have basic grid-tied electricity--and this third year of funding, known as NEDP-3, provided 351 power line extensions to Navajo families.

  17. Event cementation in sandstones

    SciTech Connect

    Robinson, A. ); Gluyas, J. )

    1991-08-01

    Precipitation of quartz overgrowths on sand grains is a common cause of porosity reduction in sandstones. The amount of quartz overgrowths (cement) often increases with depth so that the process of cementation is generally considered to be a direct response to burial and to proceed throughout the burial history of a sandstone. The authors show that some Mesozoic and Cenozoic sandstones are cemented during events 1-10 m.y. in length, periods one to two orders of magnitude less than their burial histories. Burial alone is unlikely to be the cause of quartz cementation. This new knowledge should markedly change our perception of porosity evolution in sandstones.

  18. Final Report Navajo Transmission Project (NTP)

    SciTech Connect

    Bennie Hoisington; Steven Begay

    2006-09-14

    The Din Power Authority is developing the Navajo Transmission Project (NTP) to relieve the constraints on the transmission of electricity west of the Four Corners area and to improve the operation flexibility and reliability of the extra-high-voltage transmission system in the region. The NTP creates the wholesale transmission capacity for more economical power transfers, sales, and purchases in the region. It will facilitate the development of Navajo energy resources, improve economic conditions on the Navajo Nation as well as allow DPA to participate in the western electrical utility industry.

  19. Bryce Canyon Sandstone

    USGS Multimedia Gallery

    Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandstone that forms their base. Bryce Canyon is also home to large numbe...

  20. Snow-covered Sandstone

    USGS Multimedia Gallery

    Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandstone that forms their base. Bryce Canyon is also home to large numbe...

  1. Capitol Reef Sandstone Monolith

    USGS Multimedia Gallery

    A sandstone monolith within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  2. Capitol Reef Sandstone Cliff

    USGS Multimedia Gallery

    A sandstone cliff within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  3. Chapter 2. Assessment of undiscovered conventional oil and gas resources--Upper Jurassic-Lower Cretaceous Cotton Valley group, Jurassic Smackover interior salt basins total petroleum system, in the East Texas basin and Louisiana-Mississippi salt basins provinces.

    USGS Publications Warehouse

    Dyman, T.S.; Condon, S.M.

    2006-01-01

    The Jurassic Smackover Interior Salt Basins Total Petroleum System is defined for this assessment to include (1) Upper Jurassic Smackover Formation carbonates and calcareous shales and (2) Upper Jurassic and Lower Cretaceous Cotton Valley Group organic-rich shales. The Jurassic Smackover Interior Salt Basins Total Petroleum System includes four conventional Cotton Valley assessment units: Cotton Valley Blanket Sandstone Gas (AU 50490201), Cotton Valley Massive Sandstone Gas (AU 50490202), Cotton Valley Updip Oil and Gas (AU 50490203), and Cotton Valley Hypothetical Updip Oil (AU 50490204). Together, these four assessment units are estimated to contain a mean undiscovered conventional resource of 29.81 million barrels of oil, 605.03 billion cubic feet of gas, and 19.00 million barrels of natural gas liquids. The Cotton Valley Group represents the first major influx of clastic sediment into the ancestral Gulf of Mexico. Major depocenters were located in south-central Mississippi, along the Louisiana-Mississippi border, and in northeast Texas. Reservoir properties and production characteristics were used to identify two Cotton Valley Group sandstone trends across northern Louisiana and east Texas: a high-permeability blanket-sandstone trend and a downdip, low-permeability massive-sandstone trend. Pressure gradients throughout most of both trends are normal, which is characteristic of conventional rather than continuous basin-center gas accumulations. Indications that accumulations in this trend are conventional rather than continuous include (1) gas-water contacts in at least seven fields across the blanket-sandstone trend, (2) relatively high reservoir permeabilities, and (3) high gas-production rates without fracture stimulation. Permeability is sufficiently low in the massive-sandstone trend that gas-water transition zones are vertically extensive and gas-water contacts are poorly defined. The interpreted presence of gas-water contacts within the Cotton Valley massive-sandstone trend, however, suggests that accumulations in this trend are also conventional.

  4. Pennsylvanian to Jurassic eolian transportation systems in the western United States

    USGS Publications Warehouse

    Peterson, F.

    1988-01-01

    The direction of sediment transport in eolian sandstones of Pennsylvanian to Jurassic age was interpreted from crossbedding resultants (vector means) obtained from studies of eolian rocks in the western U.S., supplemented by data from the few eolian units of eastern North America. These were compiled from the published or unpublished (theses) literature, from unpublished field data contributed by colleagues, or from measurements made for this study. In addition, new paleogeographic maps were compiled to evaluate the influence of geographic features on the atmospheric circulation patterns that are inferred from the crossbedding studies. Regionally, the crossbedding indicates northeasterly, northerly, or northwesterly winds (present coordinates) from Pennsylvanian through most of Middle Jurassic time. A rather abrupt change in wind directions occurred in late Middle Jurassic time (late part of the Callovian Age) when westerly wind patterns developed. By the Late Jurassic the winds shifted to southwesterly. Calculations of the consistency factor (vector mean strength) made from region-wide analyses of the resultants indicate fairly unidirectional winds from the Pennsylvanian through the Early Jurassic. Middle Jurassic circulation was more varied, judging from crossbedding studies in the lower part of the Entrada Sandstone. Crossbedding in Upper Jurassic eolian rocks of Wyoming and South Dakota yielded a random pattern but Upper Jurassic rocks farther south on the Colorado Plateau and adjoining areas show a return to a fairly unidirectional pattern. Comparing the resultants with their reconstructed paleogeographic setting shows surprisingly little influence of major geographic features on overall circulation patterns. However, the greatest amount of local variation occurred at or near highly indented shorelines where the temperature contrast between land and water produces local wind currents that may vary appreciably from regional circulation patterns. Although they do not cause noticeable horizontal deflections in wind patterns, small and low topographic highs appear to be able to promote the development of a dune field if a source of sand is available and if streams do not enter the growing dune field. ?? 1988.

  5. Navajo Indian medicine: implications for healing.

    PubMed

    Coulehan, J L

    1980-01-01

    Traditional medicine men coexist with physicians and hospitals on the 25,000 square mile Navajo Indian Reservation. Most seriously ill Navajos utilize both systems of health care. This natural experiment of coexistence emphasizes several general characteristics of all healing. Traditional ceremonies are successful because they are integrated into Navajo belief systems and meet needs of sick people not dealt with by the available Western medicine. Physicians and other healers simply remove obstacles to the body's restoration of homeostasis or, as the Navajo say, to harmony. Reductionism limits the spectrum of obstacles considered relevant (eg, causes of illness), but an alternate model might include emotional, social, or spiritual phenomena equally as significant to healing as are biochemical phenomena. In that context, nonmedical healers, as well as physicians, can potentially influence factors relevant to getting well. PMID:7350261

  6. Dynamics of a Phreatomagmatic Eruption at Narbona Pass Volcano, Navajo Volcanic Field, Navajo Nation, New Mexico

    NASA Astrophysics Data System (ADS)

    Brand, B. D.; Clarke, A. B.; Semken, S. C.; Sandoval, C.

    2005-12-01

    We incorporate field investigations and analytical techniques to reconstruct vent geometry and evolution, magma/water ratio, zone of fragmentation and efficiency of fragmentation of a mid-Tertiary phreatomagmatic eruption. Narbona Pass maar, located in the Chuska Mountains of northwest New Mexico, is a center in the (28-19 Ma) Navajo Volcanic Field. Minette magma erupted through a sandstone aquifer approximately 25 Ma (Cather et al., 2003) creating a phreatomagmatic sequence of bedded tuffs capped by trachybasalt lava flows. Nine stratigraphic columns were measured documenting the types, proportions and distribution of deposits around the crater. Inner crater units include massive tuff breccias, interpreted as debris flows back into the crater, and large, symmetrical cross-strata, interpreted as base surge deposits. Outer crater deposits consist of alternating bedded tuff sequences of large, symmetrical to anti-dune cross-strata, both normal and reverse graded, planar-bedded lapilli tuff, and massive lapilli tuffs and tuff breccias. Soft sediment deformation occurs only intermittently throughout the deposits and no accretionary lapilli were found, both indicative of a relatively dry phreatomagmatic eruption. The contact between pyroclastic deposits and the substrate indicates that the thickest sections were deposited in a paleo-valley (Ehrenberg, 1978). Paleo-valley fill deposits are coarser-grained than the rest of the sequence, but otherwise exhibit the same cross strata as previously described. The percentage and composition of accidental sandstone fragments remain vertically consistent through the tuff sequence, possibly suggesting a fixed zone of fragmentation. However, the accidental lithics vary in percentage depending on location around the edifice, suggesting eruption asymmetry. Zones rich in dike- and sill-sourced accidental lithics are also common in the sequence. Several angular unconformities were observed indicating partial cone collapse and enlargement of the crater during the eruption. The end of the pyroclastic sequence is characterized by fine-grained ash deposits with abundant cross-stratification and soft sediment deformation, suggesting there was no gradual drying out period before the final magmatic stage. Instead the eruption may have suddenly depleted the external water source, the zone of magma flux may have dropped below the aquifer, or the eruption may have paused before the final effusive phase.

  7. Sedimentology and sequence stratigraphy of the Lower Jurassic Kayenta Formation, Colorado Plateau, United States

    NASA Astrophysics Data System (ADS)

    Sanabria, Diego Ignacio

    2001-07-01

    Detailed outcrop analysis of the Lower Jurassic Kayenta Formation provides the basis for the formulation of a new sequence stratigraphic model for arid to semi-arid continental deposits and the generation of a comprehensive set of sedimentologic criteria for the recognition of ephemeral stream deposits. Criteria for the recognition of ephemeral deposits in the ancient record were divided into three categories according to the scale of the feature being considered. The first category takes into account sedimentary structures commonly found in the record of ephemeral stream deposits including hyperconcentrated and debris flow deposits, planar parallel bedding, sigmoidal cross-bedding, hummocky cross-bedding, climbing ripple lamination, scour-and-fill structures, convolute bedding, overturned cross-bedding, ball-and-pillow structures, pocket structures, pillars, mud curls, flaser lamination, algal lamination, termite nests, and vertebrate tracks. The second category is concerned with the mesoscale facies architecture of ephemeral stream deposits and includes waning flow successions, bedform climb, downstream accretion, terminal wadi splays, and channel-fill successions indicating catastrophic flooding. At the large-scale facies architecture level, the third category, ephemeral stream deposits are commonly arranged in depositional units characterized by a downstream decrease in grain size and scale of sedimentary structures resulting from deposition in terminal fan systems. Outcrops of the Kayenta Formation and its transition to the Navajo Sandstone along the Vermilion and Echo Cliffs of Northern Arizona indicate that wet/dry climatic cyclicity exerted a major control on regional facies architecture. Two scales of wet/dry climatic cyclicity can be recognized in northern Arizona. Three sequence sets composed of rocks accumulated under predominantly dry or wet conditions are the expression of long-term climatic cyclicity. Short-term climatic cyclicity, on the other hand, is represented by high-frequency sequences composed of eolian or ephemeral fluvial deposits overlain by perennial fluvial sediments. Increased evapotranspiration rates, depressed water tables, and accumulation of eolian or ephemeral fluvial deposits characterize the dry portion of these cycles. The wet part of the cycles is marked by an increase in precipitation and the establishment of perennial fluvial systems and lacustrine basins. This depositional model constitutes a valuable tool for correlation of similar deposits in the subsurface.

  8. Diagenetic pathways for sandstones: The role of initial composition

    SciTech Connect

    Harris, N.B.

    1995-09-01

    The initial composition of a clastic section is critical in determining the diagenetic reactions that a sandstone will undergo during burial, reactions which strongly influence its reservoir properties. The role of initial composition is illustrated for Middle Jurassic sandstones of northwest Europe (including the Brent sandstone of the North Sea) and Tertiary sandstones of the Gulf of Mexico. The composition of the former evolves from arkose to quartz arenite, with massive dissolution first of plagioclase and subsequently K-feldspar. As the bulk composition changes, the suite of clay minerals changes from kaolinite-dominated to illite-dominated, suite of clay minerals changes from kaolinite-dominated to illite-dominated, typically accompanied by a pronounced decrease in permeability. The Gulf of Mexico sandstones are also initially arkoses. Their composition, however, evolves toward a mixture of quartz and compositionally pure albite. Kaolinite remains the dominant authigenic clay within the sandstones; however detrital clays change from a Na-rich, smectitic mixed layer clay to a K-rich, illitic mixed layer clay. The contrasting diagenetic pathways result from differing mineralogy in the clastic section. The smectite-rich mudstones in the Gulf of Mexico provide a powerful sink for potassium and source of sodium. The resulting low potassium activity results in K-feldspar dissolution; it also prevents illite formation, while high sodium activity stabilizes albite. The Middle Jurassic clastic section in northwest Europe contains relatively little smectite, thus lacks the potassium sink and sodium source. Sodium activity is low, so plagioclases preferentially dissolve. K-feldspars also dissolve, but the potassium here is available for illite formation.

  9. The Role of Changing Woman and the Twins in the Navajo Origin Myth. An Effort to Correlate Navajo Legends With the Present Navajo Culture and Educational Needs.

    ERIC Educational Resources Information Center

    Mecham, Edward M.

    The Navajo origin myth is discussed by comparing recorded versions of the story of Changing Woman and the Twins. The myth clarifies the significance of many present-day tribal ceremonies and customs and provides a basis for the traditional upbringing of the Navajo child. The Navajo defines wrong as "that which produces disharmony within society,"

  10. Dual Language = Saad Ahaah Sinil. A Navajo-English Dictionary. Revised Edition.

    ERIC Educational Resources Information Center

    Austin, Martha, Ed.; Lynch, Regina, Ed.

    A dual-language Navajo-English dictionary provides a chart of the Navajo kinship system, a two-page map of the Navajo Nation, and English equivalents for Navajo words in 46 linguistic and cultural categories. Included are words for: races (Indian and other ethnic groups); Navajo clans; age groups; Navajo ceremonies; body parts; sickness; clothing;

  11. Origins of relief along contacts between eolian sandstones and overlying marine strata

    SciTech Connect

    Eschner, T.B.; Kocurek, G.

    1988-08-01

    Origins of large-scale relief along eolian-marine unit contacts, which form significant stratigraphic traps for hydrocarbons, can be recognized as inherited, reworked, and/or erosional. The Permian Rotliegende-Weissliegende Sandstone and Yellow Sands of Europe may best exemplify inherited relief in that dunes are preserved largely intact. Reworked relief, which shows significant destruction of original dune topography but with remnants of the bedforms preserved, is shown by relict Holocene dunes of coastal Australia, the Jurassic Entrada Sandstone of the San Juan basin, and the Pennsylvanian-Permian Minnelusa Formation of Wyoming. Erosional relief results from post-eolian processes and is exemplified by the Jurassic Entrada Sandstone of northeastern Utah. 11 figs., 1 tab.

  12. Deformation of Aztec Sandstone at Valley of Fire of Nevada: failure modes, sequence of deformation, structural products and their interplay with paleo fluids

    NASA Astrophysics Data System (ADS)

    Aydin, A.

    2014-12-01

    The Valley of Fire State Park, 60 km NE of Las Vegas, is a beacon of knowledge for deformation of Aztec Sandstone, a cross-bedded quartz arenite deposited in the Aztec-Navajo-Nugget erg in early Jurassic. It displays great diversity of physical properties, different localization types and micromechanics. The two deformation episodes, the Sevier folding & thrusting and the Basin & Range extension affected the area. The appearance of compaction bands marks the earliest deformation structure and their distribution, orientation, and dimension are controlled by the depositional architecture and loading. The earliest shear structures in the area are the Muddy Mountain, Summit, and Willow Tank thrusts and numerous small-scale bed-parallel faults. They altogether produced several kilometers of E-SE transport and shortening in the late Cretaceous and display numerous shear bands in its damage zone within the Aztec Sandstone. Shear bands also occur along dune boundaries and cross-bed interfaces. These observations indicate that the early deformation of the sandstone was accommodated by strain localization with various kinematics. The younger generation of faults in the area is of mid-Miocene age, and crops out pervasively. It includes a series of small offset normal faults (less than a few ten meters) which can be identified at steep cliff faces. These faults are highly segmented and are surrounded by a dense population of splay fractures. A large number of these splays were later sheared sequentially resulting in a well-defined network of left- and right-lateral strike-slip faults with slip magnitudes up to a few kilometers in the Park. The formation mechanisms of both the normal and strike-slip faults can be characterized as the sliding along planes of initial weaknesses and the accompanying cataclastic deformation. Some of the initial weak planes are associated with the depositional elements such as interdune boundaries and cross-bed interfaces while others are joint zones apparently not physically connected to any observable normal fault or dune boundary fault, but consistent with the earlier extension direction. The specific kinematics of this latter period of faulting is thought to be dictated by the orientation of the depositional and structural weaknesses and the orientation and rotation of the driving stresses.

  13. Navajo Health Authority, Board of Commissioners, Annual Report, June 1975.

    ERIC Educational Resources Information Center

    Atcitty, Thomas E.

    The Navajo Health Authority (NHA) was created by the Navajo Tribal Council to guide and assist the Navajo people to improve their health and well-being. Its goals are to: (1) develop health manpower training programs appropriate to support the development of the American Indian Medical School and to meet the needs of the American Indians in

  14. Health Problems of the Navajo Area and Suggested Interventions.

    ERIC Educational Resources Information Center

    Kaltenbach, Charles

    Analysis of morbidity, mortality, and demographic data on Navajo people was undertaken to identify leading health problems in the Navajo area and to suggest intervention activities. Comparisons with total U.S. population were made to provide perspective. Data on Navajo mortality showed: a ratio of male to female deaths of 2:1, more than 50 percent

  15. Mother Tongue Literacy and Language Renewal: The Case of Navajo.

    ERIC Educational Resources Information Center

    McCarty, Teresa L.; Dick, Galena Sells

    This paper discusses the contribution of school-based mother-tongue literacy to the maintenance and renewal of endangered languages, with Navajo as the case in point. Although Navajo claims the most speakers among U.S. indigenous languages, the absolute number and relative proportion of Navajo speakers have declined drastically in the last 30

  16. The Fears of Navajo Children: Adaptation or Pathology?

    ERIC Educational Resources Information Center

    Tikalsky, Frank D.

    1988-01-01

    Examines the literature concerning the fears of children generally and Navajo children specifically, and reviews a recent cross-cultural study with Navajo informants. Suggests that high fear frequencies in Navajo children may not indicate pathology, but may demonstrate a cultural pattern with important adaptive value. Contains 10 references. (SV)

  17. A Manual for Navajo Community School Board Members.

    ERIC Educational Resources Information Center

    Stout, Irving W., Ed.

    In August of 1969, the Navajo Tribe adopted a school code pertaining to the development and operation of Navajo Community School Boards. The code provided the legal basis for such organization and its operation on the reservation. This document furnishes a broad general outline of the duties and responsibilities of Navajo School Board members.

  18. The Navajo Code Talkers: A Secret World War II Memorandum.

    ERIC Educational Resources Information Center

    Jevec, Adam; Potter, Lee Ann

    2001-01-01

    Provides background information on the development of and work performed by the Navajo code talkers during World War II. Includes teaching activities for classroom use as well as examples from the code. Includes the Navajo dictionary and words with the English and Navajo meaning. (CMK)

  19. 78 FR 17422 - Navajo Nation; Major Disaster and Related Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-21

    ... SECURITY Federal Emergency Management Agency Navajo Nation; Major Disaster and Related Determinations... Presidential declaration of a major disaster for the Navajo Nation (FEMA-4104-DR), dated March 5, 2013, and...''), as follows: I have determined that the damage to the lands associated with the Navajo...

  20. 78 FR 17743 - Navajo Nation Disaster #AZ-00026

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-22

    ... ADMINISTRATION Navajo Nation Disaster AZ-00026 AGENCY: U.S. Small Business Administration. ACTION: Notice... for the Navajo Nation (FEMA-4104- DR), dated 03/05/2013. Incident: Severe Freeze. Incident Period: 12...: Primary Areas: Navajo Nation and Associated Lands. The Interest Rates are: For Physical Damage:...

  1. Prospects for the Survival of the Navajo Language: A Reconsideration.

    ERIC Educational Resources Information Center

    Spolsky, Bernard

    This paper aims to reassess conclusions drawn in 1975 about the prospects for survival of the Navajo language. A study done at that time uncovered evidence that there was increasing knowledge of English among Navajo children, although knowledge of English was highly, positively correlated to the level of isolation from Navajo speakers. As a result

  2. Health Problems of the Navajo Area and Suggested Interventions.

    ERIC Educational Resources Information Center

    Kaltenbach, Charles

    Analysis of morbidity, mortality, and demographic data on Navajo people was undertaken to identify leading health problems in the Navajo area and to suggest intervention activities. Comparisons with total U.S. population were made to provide perspective. Data on Navajo mortality showed: a ratio of male to female deaths of 2:1, more than 50 percent…

  3. U.S. SCHOOL ADMINISTRATORS LEARN OF NAVAJO "REVOLUTION".

    ERIC Educational Resources Information Center

    BENHAM, WILLIAM J., JR.

    NAVAJO CULTURE AND LANGUAGE ARE QUITE DIFFERENT FROM THAT OF OTHER AMERICANS, AND HELP TO ACCOUNT FOR GENERALLY LOW SUCCESS OF NAVAJO CHILDREN IN THE CLASSROOM. BY NOVEMBER 1966, WHEN TITLE I OF THE ELEMENTARY AND SECONDARY EDUCATION ACT HAD BECOME AVAILABLE TO FEDERAL SCHOOLS, THE NAVAJO TRIBAL COUNCIL'S EDUCATION COMMITTEE HAD DECIDED THAT WHAT

  4. Verb Nominalization and Categorization in Navajo Children's Speech.

    ERIC Educational Resources Information Center

    Iris, Madelyn Anne

    Verb nominalization in Navajo is a strategy by which children create category labels when the adult lexical item is not known; it allows for the creation of uniquely descriptive category labels. This study was based on a series of interviews with Navajo children aged four-and-a-half to approximately ten years, all native speakers of Navajo with…

  5. Navajos: A Source Booklet for Teachers and Students.

    ERIC Educational Resources Information Center

    David, Anna, Ed.

    As part of the National Education Association (NEA) Mastery in Learning Project, faculty and students of the Greasewood/Toyei Consolidated Boarding School developed a booklet of Navajo students' work. The purpose of the booklet is to promote better understanding of the Navajo culture. Navajo culture emphasizes respect for the earth, reverence of

  6. Middle Jurassic sand reservoirs of Tazovskoe field (West Siberia)

    NASA Astrophysics Data System (ADS)

    Kurasov, I. A.

    2012-12-01

    Perspectives of Tazovskoe field Jurassic strata development are associated with lithological and mineralogical characteristics of reservoirs, which are the main reserve of the region, because of the high rate of depletion of the most prolific Cenomanian gas pools. Tazovskoye field is multibedded and is unique in terms of hydrocarbon reserves. Middle Jurassic strata occur everywhere and are represented by rocks of the Tyumenskaya formation, comprising layers J2 - J5. The producing horizons are composed of sandstones, sandy siltstones, cemented by shaly-carbonate cement mass. According to laboratory data, the Jurassic reservoirs are characterized by a wide range of porosity (up to 22.5%) and mainly low permeability (up to 2 mD), except for a few samples of J3 reservoir with permeability up to 100-150 mD. Test objects were the core samples taken from 7 intervals of the well T-83 and logging data from 4 intervals of wells 73, 93 in the Tazovskoye field. Depth and core recovery from T-83 well of the Tazovskoye field are shown in Table 1. Total linear core recovery from the Jurassic strata was 79.4 m. Late Bajocian-Bathonian alluvial-lacustrine strata compose the first regressive cycle of sedimentation in the Tazovskoye field. They are represented by alternating thin sandy, siltstone-sandy, siltstone, shaly-siltstone, siltstone-shaly, and shaly rocks with coal interbeds. They include three main productive formations: J2, J3 and J4. Above in the vertical section, the Upper Jurassic rocks occur, while lower, basal strata of the Callovian stage overlay them with a distinct unconformity. In the Upper Jurassic time, the main transgression phase of the Jurassic period occurred over the whole territory of the Western Siberia. These strata are built by non-uniform alternating sandstones, siltstones and shales with coal interbeds of the continental genesis (alluvial-lacustrine); The reservoirs contain cyclites that as a rule have binary structure, less often - ternary structure: the lower element of cyclites is represented by sandy and siltstone-sandy strata formed in a channel and in a point-bar, the upper element of cyclites is represented by siltstone, siltstone-shaly, shaly, and carbonaceous-shaly strata formed in the floodplain or in lacustrine-boggy sedimentation environment; The producing strata of J2-J4 formations are characterized in general by moderate porosity (11-17%) and low permeability (1 mD); This genetic type of the Middle Jurassic reservoirs is typical throughout the Pur-Taz petroleum region, as well is possible for the Nadym-Pur petroleum region, except for the most eastern areas of Nadym, where these rocks have flysch nature, and therefore one can predict their presence in adjacent fields, where the Jurassic reservoirs are not discovered yet.Core recoveries from T83 well;

  7. Jurassic Park: Adventure in Learning.

    ERIC Educational Resources Information Center

    Shams, Marcia; Boteler, Trina

    1993-01-01

    Describes using the movie "Jurassic Park" as a foundation for a middle school interdisciplinary unit involving science, math, language arts, history, and geography. Suggested books and activities are presented. (PR)

  8. Sedimentology and invertebrate paleontology of Triassic and Jurassic Lacustrine deposits, Culpeper Basin, northern Virginia

    NASA Astrophysics Data System (ADS)

    Gore, P. J. W.

    The Culpeper Basin contains late Triassic and early Jurassic continental sedimentary rocks. Lacustrine rocks are present in the Bull Run Formation, Buckland Formation, and Waterfall formation. The lacustrine rocks were grouped into eight lithofacies using cluster analysis: (1) red massive siltstone or mudstone, (2) gray massive siltsone or mudstone, (3) disrupted graded siltstone and mudstone, (4) laminated mudstone, (5) limestone, (6) black shale, (7) red laminated and cross-laminated siltstone, sandstone, and mudstone, and (8) sandstone. Freshwater invertebrate fossils (conchostracans, notostracans, ostracodes, and pelecypods) which inhabited shallow water are abundant in some lacustrine beds. The Culpeper Basin notostracans (Triops) are the first to be reported from the Triassic of North America. The conchostracans, Cyzicus and Cornia may be useful for correlation in the Culpeper Basin. Cyzicus is present in the Triassic Bull Run Formation. Cornia is present in the Jurassic Waterfall Formation. This is the first report of Cornia from the Newark Supergroup.

  9. JURASSIC Retrieval Processing

    NASA Astrophysics Data System (ADS)

    Blank, J.; Ungermann, J.; Guggenmoser, T.; Kaufmann, M.; Riese, M.

    2012-04-01

    The Gimballed Limb Observer for Radiance Imaging in the Atmosphere (GLORIA) is an aircraft based infrared limb-sounder. This presentation will give an overview of the retrieval techniques used for the analysis of data produced by the GLORIA instrument. For data processing, the JUelich RApid Spectral SImulation Code 2 (JURASSIC2) was developed. It consists of a set of programs to retrieve atmospheric profiles from GLORIA measurements. The GLORIA Michelson interferometer can run with a wide range of parameters. In the dynamics mode, spectra are generate with a medium spectral and a very high temporal and spatial resolution. Each sample can contain thousands of spectral lines for each contributing trace gas. In the JURASSIC retrieval code this is handled by using a radiative transport model based on the Emissivity Growth Approximation. Deciding which samples should be included in the retrieval is a non-trivial task and requires specific domain knowledge. To ease this problem we developed an automatic selection program by analysing the Shannon information content. By taking into account data for all relevant trace gases and instrument effects, optimal integrated spectral windows are computed. This includes considerations for cross-influence of trace gases, which has non-obvious consequence for the contribution of spectral samples. We developed methods to assess the influence of spectral windows on the retrieval. While we can not exhaustively search the whole range of possible spectral sample combinations, it is possible to optimize information content using a genetic algorithm. The GLORIA instrument is mounted with a viewing direction perpendicular to the flight direction. A gimbal frame makes it possible to move the instrument 45 to both direction. By flying on a circular path, it is possible to generate images of an area of interest from a wide range of angles. These can be analyzed in a 3D-tomographic fashion, which yields superior spatial resolution along line of site. Usually limb instruments have a resolution of several hundred kilometers. In studies we have shown to get a resolution of 35km in all horizontal directions. Even when only linear flight patterns can be realized, resolutions of ?70km can be obtained. This technique can be used to observe features of the Upper Troposphere Lower Stratosphere (UTLS), where important mixing processes take place. Especially tropopause folds are difficult to image, as their main features need to be along line of flight when using common 1D approach.

  10. Map showing ground-water conditions in the Kaibito and Tuba City areas, Coconino and Navajo counties, Arizona, 1978

    USGS Publications Warehouse

    Farrar, C.D.

    1978-01-01

    The Kaibito and Tuba City areas include about 2,500 square miles in north-central Arizona. Ground water is obtained from the N aquifer and from alluvium. The N aquifer consists of Navajo Sandstone, Kayenta Formation, Moenave Formation, and the Lukachukai Member of the Wingate Sandstone. The main source of ground water is the Navajo Sandstone. Ground-water development has been slight in the areas. In 1977 the estimated ground-water withdrawals were about 350 acre-feet in the Kaibito area and 650 acre-feet in the Tuba City area. Water levels ranged from flowing at the land surface to 1,360 feet below the land surface. The chemical quality of the water in the N aquifer does not vary greatly in the areas. Dissolved-solids concentrations in the water range from 101 to 669 milligrams per liter but generally are less than 300 milligrams per liter. Along some of the valleys in the Kaibito and Tuba City areas, the alluvium yields water to many shallow dug wells. The water levels generally are from 5 to 15 feet below the land surface. Dissolved-solids concentrations in water from the alluvium usually are less than 600 milligrams per liter. Information shown on the map (scale 1:125,000) includes depth to water, altitude of the water level, and specific conductance and fluoride concentrations. (Woodard-USGS)

  11. Middle Jurassic incised valley fill (eolian/estuarine) and nearshore marine petroleum reservoirs, Powder River basin

    SciTech Connect

    Ahlbrandt, T.S.; Fox, J.E.

    1997-07-01

    Paleovalleys incised into the Triassic Spearfish Formation (Chugwater equivalent) are filled with a vertical sequence of eolian, estuarine, and marine sandstones of the Middle Jurassic (Bathonian age) Canyon Springs Sandstone Member of the Sundance Formation. An outcrop exemplifying this is located at Red Canyon in the southern Black Hills, Fall River County, South Dakota. These paleovalleys locally have more than 300 ft of relief and are as much as several miles wide. Because they slope in a westerly direction, and Jurassic seas transgressed into the area from the west there was greater marine-influence and more stratigraphic complexity in the subsurface, to the west, as compared to the Black Hills outcrops. In the subsurface two distinctive reservoir sandstone beds within the Canyon Springs Sandstone Member fill the paleovalleys. These are the eolian lower Canyon Springs unit (LCS) and the estuarine upper Canyon Springs unit (UCS), separated by the marine {open_quotes}Limestone Marker{close_quotes} and estuarine {open_quotes}Brown Shale{close_quotes}. The LCS and UCS contain significant proven hydrocarbon reservoirs in Wyoming (about 500 MMBO in-place in 9 fields, 188 MMBO produced through 1993) and are prospective in western South Dakota, western Nebraska and northern Colorado. Also prospective is the Callovian-age Hulett Sandstone Member which consists of multiple prograding shoreface to foreshore parasequences, as interpreted from the Red Canyon locality. Petrographic, outcrop and subsurface studies demonstrate the viability of both the Canyon Springs Sandstone and Hulett Sandstone members as superior hydrocarbon reservoirs in both stratigraphic and structural traps. Examples of fields with hydrocarbon production from the Canyon Springs in paleovalleys include Lance Creek field (56 MMBO produced) and the more recently discovered Red Bird field (300 MBO produced), both in Niobrara County, Wyoming.

  12. Language Learning in the American Southwestern Borderlands: Navajo Speakers and Their Transition to Academic English Literacy.

    ERIC Educational Resources Information Center

    Dyc, Gloria

    2002-01-01

    The Navajo Nation wants a 2-year Navajo language requirement for regional colleges. At the same time, literacy in academic English is required for Navajo students wishing to enter the sciences, medicine, and law. The difficulties students face as they make the transition from English to Navajo and from Navajo to English are described. Four

  13. Navajo Participation in Labor Unions. Lake Powell Research Project Bulletin Number 15, December 1975.

    ERIC Educational Resources Information Center

    Robbins, Lynn A.

    Navajo participation in labor unions and Navajo labor relations have undergone rapid and fundamental changes since the development of industry around Lake Powell and on Black Mesa. Early attempts to unionize Navajo workers met with stiff resistance from employees and the Navajo Tribal Council. Union entry into the Navajo Reservation was viewed as

  14. The Navajo Way of Life: A Resource Unit with Activities for Grades 4-6.

    ERIC Educational Resources Information Center

    Cordova, Dahlia

    A resource unit on the Navajo way of life, for grades 4-6, contains sections on Navajo history, art, and crafts, homes, music, poetry and games; Navajo and Pueblo cookery (including recipes); traditional Navajo dress, ceremony and legends; and successful Navajos, past and present. Sections include text, vocabulary words, drawings, maps, and

  15. Reclaiming Indigenous Intellectual, Political, and Geographic Space: A Path for Navajo Nationhood

    ERIC Educational Resources Information Center

    Lee, Lloyd L.

    2008-01-01

    For millennia, Navajo society was self-sufficient. After 1863, beginning with Kit Carson's murderous rampage among the Navajo and the subsequent removal to the Bosque Redondo reservation, Navajo nationhood changed. Navajo society began a slow transformation away from the distinct Dine way of life. In the twentieth century Navajo nationalism was

  16. Determinants of Blood Pressure in Navajo Adolescents.

    ERIC Educational Resources Information Center

    Coulehan, John L.; And Others

    1990-01-01

    Among 580 Navajo adolescents, 11.1 percent of males and 1.6 percent of females had high blood pressure. Blood pressure was related to age in males and to body mass index in females but was not related to level of acculturation or traditionality. Contains 17 references. (SV)

  17. Aquia Creek Sandstone

    USGS Multimedia Gallery

    This Aquia Creek Sandstone originated from a quarry about 40 miles south of Washington, D.C., in Stafford County, Va. This type of stone was used in the construction of many of D.C.'s most famous landmarks, including the White House and the U.S. Capitol building....

  18. Sand and sandstone

    SciTech Connect

    Pettijohn, F.J.; Potter, P.E.; Siever, R.

    1987-01-01

    Here is a new, second edition of a classical textbook in sedimentology, petrology, and petrography of sand and sandstones. It has been extensively revised and updated, including: new techniques and their utility; new literature; new illustrations; new, explicitly stated problems for the student; and a wider scope.

  19. Sandstone and Moon

    USGS Multimedia Gallery

    Views along the Queen's Garden Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sands...

  20. Lichen on Sandstone

    USGS Multimedia Gallery

    Lichen on sandstone in Pine Creek Canyon. Lichen is a composite organism made up of algae and fungi, which form a symbiotic relationship. Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Roc...

  1. Controls on the variability of net infiltration to desert sandstone

    USGS Publications Warehouse

    Heilweil, V.M.; McKinney, T.S.; Zhdanov, M.S.; Watt, D.E.

    2007-01-01

    As populations grow in and climates and desert bedrock aquifers are increasingly targeted for future development, understanding and quantifying the spatial variability of net infiltration becomes critically important for accurately inventorying water resources and mapping contamination vulnerability. This paper presents a conceptual model of net infiltration to desert sandstone and then develops an empirical equation for its spatial quantification at the watershed scale using linear least squares inversion methods for evaluating controlling parameters (independent variables) based on estimated net infiltration rates (dependent variables). Net infiltration rates used for this regression analysis were calculated from environmental tracers in boreholes and more than 3000 linear meters of vadose zone excavations in an upland basin in southwestern Utah underlain by Navajo sandstone. Soil coarseness, distance to upgradient outcrop, and topographic slope were shown to be the primary physical parameters controlling the spatial variability of net infiltration. Although the method should be transferable to other desert sandstone settings for determining the relative spatial distribution of net infiltration, further study is needed to evaluate the effects of other potential parameters such as slope aspect, outcrop parameters, and climate on absolute net infiltration rates. Copyright 2007 by the American Geophysical Union.

  2. Frisco City sand: New Jurassic reservoir in southwest Alabama

    SciTech Connect

    Mann, S.D.; Mink, R.M.; Bearden, B.L. ); Schneeflock, R.D. Jr. )

    1989-09-01

    The first commercial production of hydrocarbons from the Jurassic Haynesville Formation in southwestern Alabama was from the Frisco City field. The field currently produces 57.8{degree} API gravity oil on 160-ac well spacing from a depth of approximately 12,000 ft. Perforations are in the Frisco City sand interval, in the lower part of the Haynesville Formation. Average porosity is 15% and average permeability is 45 md. Currently, the field has two producing wells with cumulative production of over 138,876 bbl of oil and 213,144 mcf of gas. The hydrocarbon trap in the Frisco City field is a combination structural-stratigraphic trap. The Frisco City sand reservoir is located on a faulted anticline. The stratigraphic trap is produced by a permeability barrier near the crest of the structure and termination against a basement high. The lower part of the Haynesville Formation in this area is comprised of (in ascending order) the Buckner Anhydrite Member, the Frisco City sand, and interbedded shale and anhydrite. Sandstones of the Frisco City sand interval were deposited in a shallow marine setting and have a sheetlike morphology. The sandstones are poorly to moderately sorted, angular to rounded arkose, and contain angular to rounded pebbles. The sandstones are interbedded with thin, sandy, mudstones that contribute, along with patchy carbonate and anhydrite cement, to considerable reservoir heterogeneity. Porosity is predominantly primary intergranular with a small amount of framework grain dissolution and decementation.

  3. The Achievement Gap. A Comparison of Anglo and Navajo Student Writing Samples.

    ERIC Educational Resources Information Center

    Ashmore, Rhea; Shields, Carolyn

    2002-01-01

    Compares writing performance of Anglo American and Navajo students in grades 7 and 11 by gender and ethnicity. Finds, for example, that Navajo female students' writing is longer and more expressive than that of Navajo males. (Contains 40 references.) (PKP)

  4. Effects of stratigraphic heterogeneity on permeability in eolian sandstone sequence, Page sandstone, northern Arizona

    SciTech Connect

    Chandler, M.A.; Kocurek, G.; Goggin, D.J.; Lake, L.W.

    1989-05-01

    Outcrop and core data from the eolian Middle Jurassic Page Sandstone of northern Arizona show that realistic reservoir characterization can be based on the stratigraphic architecture. Outcrop displays of differential weathering, coloration, cementation, and seepage reflect stratigraphic control of fluid flow within the sandstone. Measurements of permeability using a field permeameter and conventional analysis yield a five-order-of-magnitude range of values between distinct populations. Extra-erg and/or interdune deposits are least permeable (0.67-1800 md), followed by wind-ripple strata (900-5200 md), with grain-flow strata being the most permeable (3700-12,000 md). Extra-erg and interdune deposits and some extensive bounding surfaces form significant flow barriers and tend to compartmentalize the reservoir. Reservoir characteristics of the dune cross-strata are a function of the types, distributions, and orientations of the internal stratification. Directional-flow properties within the strata are most pronounced within wind-ripple laminae. Recognition of the levels of reservoir heterogeneity is sampling-scale dependent. General models for flow within single sets of cross-strata as well as within eolian sequences can be generated based upon relative permeability between stratigraphic units. 9 figures.

  5. Lung cancer among Navajo uranium miners

    SciTech Connect

    Gottlieb, L.S.; Husen, L.A.

    1982-04-01

    Lung cancer has been a rare disease among the Indians of the southwestern United States. However, the advent of uranium mining in the area has been associated with an increased incidence of lung cancer among Navajo uranium miners. This study centers on Navajo men with lung cancer who were admitted to the hospital from February 1965 to May 1979. Of a total of 17 patients with lung cancer, 16 were uranium miners, and one was a nonminer. The mean value of cumulative radon exposure for this group was 1139.5 working level months (WLMs). The predominant cancer type was the small cell undifferentiated category (62.5 percent). The low frequency of cigarette smoking in this group supports the view that radiation is the primary cause of lung cancer among uranium miners and that cigarette smoking acts as a promoting agent.

  6. Long term effects of CO2 on 3-D pore structure and 3-D phase distribution in reservoir sandstones from the Green River well (Utah, USA)

    NASA Astrophysics Data System (ADS)

    Barnhoorn, Auke; Kisoensingh, Shailesh

    2014-05-01

    Reservoir sandstones and cap rocks from the Green River area in Utah (USA) have been naturally exposed to CO2 fluids for hundreds of thousands of years, leading to compositional and microstructural alterations of the rocks. A 300m long section of this section of these Green river reservoir and cap rocks has been cored in 2012. Here, results of a high-resolution micro X-ray tomography study of a suite of samples from the well are reported detailing the 3D pore structure and phase distribution changes due to long term CO2 exposure. The reservoir sandstones from the Green River well (Utah) reveal the presence of various degrees of carbonate precipitation in the pores. Both reservoir sandstones (the shallower Entrada Formation and the deeper Navajo Formation) show variations in carbonate content and porosity structure. The Entrada sandstone exhibits widespread carbonate precipitation (up to 60% of infill of the original porosity), with the largest amount of carbonates at the boundary with the underlying Carmel cap rock. In an interval of a meter from the contact, carbonate precipitation decreases sharply till ~20%. The porosity is significantly reduced in the lowest 1 meter. The reduction in porosity lead to a reduction in pore connectivity and thereby permeability by the long-term CO2 exposure. On the other hand the Navajo sandstone shows predominantly only isolated spots of carbonate precipitation (up to 20% of the original porosity). Widespread carbonate precipitation is absent in the Navajo reservoir sandstone samples. Because carbonate precipitation is not present throughout, the large-scale permeability of the formation is likely not significantly affected by the CO2 exposure. The results show how the 3D distribution of the phases and the 3D shapes of the pores are affected by long term CO2 exposure and can be used as an example for potential changes to be expected in reservoir sandstones due to CO2 storage in future CO2 sequestration endeavours.

  7. Incidence and prevalence of Parkinson's disease among Navajo people living in the Navajo nation.

    PubMed

    Gordon, Paul H; Mehal, Jason M; Holman, Robert C; Bartholomew, Michael L; Cheek, James E; Rowland, Andrew S

    2015-04-15

    Parkinson's disease (PD) is largely unstudied among American Indians. Unique populations might harbor clues to elusive causes. We describe the incidence and prevalence of PD among Navajo people residing in the Navajo Nation, home to the largest American Indian tribe in the United States. We analyzed 2001-2011 inpatient and outpatient visit data for Navajo people obtained from the Indian Health Service, which provides health care to American Indian people living on the Navajo Reservation. Cases were defined by at least two inpatient or outpatient visits with the diagnosis of PD. Crude and age-adjusted incidence and prevalence rates were calculated overall as well as by age, sex, region of residence, and time period. Five hundred twenty-four Navajo people with median age-at-onset of 74.0 years were diagnosed with PD during the study period, yielding an average annual crude incidence rate of 22.5/100,000. Age-specific incidence was 232.0 for patients 65 years of age or older and 302.0 for 80 years of age or older. Age-adjusted incidence was 35.9 overall (238.1 for ?65 years), was higher in men than in women (47.5 vs. 27.7; P<0.001), varied by region (P=0.03), and was similar between time periods (2002-2004 vs. 2009-2011). The age-adjusted point prevalence rate was 261.0. The rate of PD among Navajo People appears to be as high as or higher than rates reported in many other populations. Rates increased to the highest age group, consistent with population-based studies. Further investigation is warranted to examine risk factors for PD in this remote population. PMID:25649219

  8. Replacement geometry and fabrics of Smackover (Jurassic) dolomite, southern Alabama

    SciTech Connect

    Barrett, M.L.

    1986-09-01

    The intensity of dolomitization and associated reservoir development in the Smackover Formation, Conecuh Ridge-Wiggens arch areas, is not predictable by comparison with time-temperature index methods or porosity-depth curves. Major alteration patterns and associated dolomite fabrics reflect the early paleotopographic settings, where high fluid flux and massive replacement are associated with Late Jurassic basement highs. This large-scale replacement is most important in the lowermost Smackover section overlying the Norphlet sandstone from Chunchula field into the Manila Embayment. The heterogeneous nature of dolomite reservoir development is evident in Chunchula field, where local pods of permeable dolomite cut across sedimentary facies boundaries. Predicting the orientation of a dolomite permeability barrier where there is little well control can be facilitated by mapping the regional thickness variations; the extension of impermeable dolomite trends is generally parallel to isopach trends.

  9. Middle Jurassic strata link Wallowa, Olds Ferry, and Izee terranes in the accreted Blue Mountains island arc, northeastern Oregon

    SciTech Connect

    White, J.D.L. ); Vallier, T. ); Stanley, G.D. Jr. ); Ash, S.R. ); White, D.L.

    1992-08-01

    Middle Jurassic strata atop the Wallowa terrane in northeastern Oregon link the Wallowa, Izee, and Olds Ferry terranes as related elements of a single long-lived and complex oceanic feature, the Blue Mountains island arc. Middle Jurassic strata in the Wallowa terrane include a dacitic ash-flow deposit and contain fossil corals and bivalves of North American affinity. Plant fossils in fluvial sandstones support a Jurassic age and indicate a seasonal temperate climate. Corals in a transgressive sequence traditionally overlying the fluvial units are of Bajocian age and are closely related to endemic varieties of the Western Interior embayment. They are unlike Middle Jurassic corals in other Cordilleran terranes; their presence suggests that the Blue Mountains island arc first approached the North American craton at high paleolatitudes in Middle Jurassic time. The authors consider the Bajocian marine strata and underlying fluvial volcaniclastic units to be a basin-margin equivalent of the Izee terrane, a largely Middle Jurassic (Bajocian) succession of basinal volcaniclastic and volcanic rocks known to overlie the Olds Ferry and Baker terranes.

  10. Potential tight gas resources in a frontier province - Jurassic through Tertiary strata beneath the Brooks Range foothills, Arctic Alaska

    USGS Publications Warehouse

    Nelson, Philip H.; Bird, Kenneth J.; Houseknecht, David W.; Potter, Christopher J.; Moore, Thomas E.

    2006-01-01

    Beneath the foothills of the Brooks Range, rocks of the Lower Cretaceous-Tertiary Brookian and Jurassic-Lower Cretaceous Beaufortian megasequences have been deeply buried and exhumed, and now exhibit characteristics of 'tight gas sandstones'. The data recovered from drilling, well tests, and cores exhibit the potential for substantial gas reserves over a large area. These data include recovery of gas from drillstem tests, indications of overpressure from well tests and mud weights, low porosity and permeability in sandstones, and vitrinite reflectance values ranging from 1.0 to 2.0 percent throughout substantial depth intervals.

  11. Recent Jurassic discoveries in southeastern Cass County, Texas

    SciTech Connect

    Aubrey, J.

    1984-09-01

    Southeastern Cass County had lain virtually dormant as a prospective Jurassic oil and gas province since the mid-1960s, when East Linden field was discovered and developed. Then, in 1978, Hilliard Oil and Gas drilled the 1 Johnson and discovered Kildare field (Smackover). Subsequent development thru 1982 proved additional reserves in several Cotton Valley sandstones as well, reconfirming southeastern Cass County as territory for viable Jurassic drilling. Additional drilling occurred when Marshall Exploration redrilled and expanded the old Bloomburg field and Heflin redrilled Queen City field. All of this drilling was successful in the Smackover reservoir, finding sour gas and condensate. Wildcat activity included the two Smackover completions finding South Atlanta field, as well as two completions in formations that are highly debated as to their nomenclature. Cities Service reportedly their well in the Eagle Mills. This well brought national attention to southeastern Cass County, when it was reported on the CBS Saturday evening news. The well initially flowed at rates that were as high as 1800 BOPD, 1396 MCFGD, and 32 BWPD, with pressure of 3250 psi. Just as the excitement was dying down, Primary Fuels, Inc. reentered and deepened the Highland Resources 1 Glass and completed that well in a zone correlative to the Cities Service 1-A Pruitt. The 1 glass potentialed for 200 BOPD, 570 MCFGD, and 32 BWPD, at pressure of 2900 psi. The producing zone was determined to be the Norphlet, which once again was made wildcatters of all previous upper Smackover explorers.

  12. Mask of Black God: The Pleiades in Navajo Cosmology

    ERIC Educational Resources Information Center

    Schulz, Teresa M.

    2005-01-01

    One Navajo legend attributes the creation of the primary stars and constellations to Black God. Today, a famous star cluster--the Pleiades--often appears on the traditional mask worn by chanters impersonating Black God during special ceremonies. In this case study, students learn about the Pleiades in Navajo cosmology while honing their…

  13. Navajo Uranium Education Programs: The Search for Environmental Justice

    ERIC Educational Resources Information Center

    Charley, Perry H.; Dawson, Susan E.; Madsen, Gary E.; Spykerman, Bryan R.

    2004-01-01

    Uranium mining and milling in the Four Corners' area of the American Southwest has had serious negative impacts on American Indian workers, their families, and their communities. In this article, we will examine Navajo education programs which inform citizens about risks and health impacts associated with radiation exposures. Because the Navajo

  14. Social Interaction Patterns and Relative Urban Success: the Denver Navajo

    ERIC Educational Resources Information Center

    Snyder, Peter Z.

    1973-01-01

    This examination of the social factors of urban adaptation of Navajo Indian migrants to Denver, Colorado--based on reference-membership group theory--attempts to isolate primary groups within the Navajo urban enclave'' to investigate the relationship of group membership to adaptation. (JM)

  15. "Dine Bikeya": Teaching about Navajo Citizenship and Sovereignty

    ERIC Educational Resources Information Center

    Washington, Elizabeth Yeager; van Hover, Stephanie

    2011-01-01

    The Navajo Nation, comprising the largest land area allocated mainly to a Native American jurisdiction in the United States, offers a unique opportunity to enhance students' understandings of citizenship rights and sovereignty. For example, what does sovereignty mean on the reservation? What is the relationship between the Navajo Nation and the

  16. Navajo Archaeologist Is Not an Oxymoron: A Tribal Archaeologist's Experience

    ERIC Educational Resources Information Center

    Two Bears, Davina R.

    2006-01-01

    Many Navajos, or Dines, and Native American people in general, are archaeologists or are becoming archaeologists. The distinction between "Native Americans" and "archaeologists" in academia, or elsewhere, is no longer accurate. This fact should not come as such a surprise. As the epigraph, a quote by Richard Begay, demonstrates, Navajo people, for

  17. Oral History Shares the Wealth of a Navajo Community.

    ERIC Educational Resources Information Center

    Begay, Sara L.; Jimmie, Mary; Lockard, Louise

    This paper describes a collaborative project in which K-3 Navajo students used oral history interviews, archival photos, and primary documents to explore the history of their communities. Participating students attended schools that were implementing the Dine (Navajo) Language and Culture teaching perspective, which is based on the premises that

  18. Navajo Archaeologist Is Not an Oxymoron: A Tribal Archaeologist's Experience

    ERIC Educational Resources Information Center

    Two Bears, Davina R.

    2006-01-01

    Many Navajos, or Dines, and Native American people in general, are archaeologists or are becoming archaeologists. The distinction between "Native Americans" and "archaeologists" in academia, or elsewhere, is no longer accurate. This fact should not come as such a surprise. As the epigraph, a quote by Richard Begay, demonstrates, Navajo people, for…

  19. Mask of Black God: The Pleiades in Navajo Cosmology

    ERIC Educational Resources Information Center

    Schulz, Teresa M.

    2005-01-01

    One Navajo legend attributes the creation of the primary stars and constellations to Black God. Today, a famous star cluster--the Pleiades--often appears on the traditional mask worn by chanters impersonating Black God during special ceremonies. In this case study, students learn about the Pleiades in Navajo cosmology while honing their

  20. Navajo Area Health and Physical Education Curriculum Guidelines.

    ERIC Educational Resources Information Center

    Tomah, Kent; And Others

    Based on health education needs of Navajo children as established by the Navajo Area health and physical education committees, this curriculum guideline for health and physical education is delineated into three phases reflecting emphasis of instructional techniques (introductory, exploration/extended learning, widened learning) and three levels…

  1. The Navajo Agricultural Projects Industry: Subsistence Farming to Corporate Agribusiness.

    ERIC Educational Resources Information Center

    Barry, Tom

    1979-01-01

    Originally designed to create small farms for individual Navajos, the irrigation project has grown into a single 110,000-acre corporate agribusiness, the land's management has fallen out of the grasp of individual Navajos, and the idea of subsistence farming has been plowed under for the planting of major money-making crops. (NQ)

  2. Oedipal equivalents in a clan culture: reflections on Navajo ways.

    PubMed

    Proskauer, S

    1980-02-01

    Patterns have emerged in anthropological and clinical work with Navajos which seem inconsistent with out present formulation of the Oedipus complex and its place in the emotional maturation process. This paper evolved out of an effort to reconcile psychoanalytic concepts with Navajo symptoms, experiences, feelings, and beliefs. PMID:7355180

  3. Navajo Community College--The President's Report, 1979-80.

    ERIC Educational Resources Information Center

    Jackson, Dean C.

    An overview of the Navajo Community College (NCC) is presented with a message from the president and facts pertaining to both the Tsaile and Shiprock campuses. NCC President Jackson states that the uniqueness of NCC lies primarily in the instructional area which promotes the use of educational concepts contained in the Navajo culture to reinforce

  4. Palaeoenvironmental and sequence stratigraphic analyses of the Jurassic Datta Formation, Salt Range, Pakistan

    NASA Astrophysics Data System (ADS)

    Iqbal, Shahid; Jan, Irfan U.; Akhter, M. Gulraiz; Bibi, Mehwish

    2015-06-01

    The Lower Jurassic Datta Formation, western Salt Range, Pakistan, comprises three facies associations: (1) channel belt facies association (CBFA), (2) channel margin, and overbank facies association (CMOFA), and (3) lagoonal facies association (LFA). A cyclic fining-upward trend in the succession is represented by basal quartzose conglomerate/pebbly sandstone, through coarse to fine quartzose sandstone to siltstone and shales/claystone, which contains some carbonate accumulation. Two prominent depositional sequences are recognized in the Datta Formation with the lower high and upper low magnitude cycles. The Datta Formation thus represents a thick sedimentary succession and in the study area, i.e., western Salt Range, mainly channel belt, flood plain and/or delta top facies are exposed. The palaeocurrent analysis shows that the source area with acidic plutonic rocks laid to S-SE in the Indian shield, aravalies or older sedimentary rocks of the Indus Basin (i.e., Khewra, Tobra and Warchha formations). A tentative stratigraphic correlation of the Datta Formation with the lower Jurassic Lathi Formation, India invites further work in parts of India, which will elaborate the extent of the Datta Formation in the Greater Indian peninsula and develop palaeogeographic setting for this Lower Jurassic deltaic rock unit.

  5. Laughter: The Navajo Way. Humorous Stories of the People (in Navajo and English) Volume One.

    ERIC Educational Resources Information Center

    Wilson, Alan; Dennison, Gene

    This book has been prepared for the use of teachers, ethnologists, linguists, Indian studies scholars, language students and those who have an interest in the languages and cultures of the earlier inhabitants of this continent. The stories reflect the Navajo love for and genius with words and humor. Most of the humor represented is of three basic

  6. Revisiting the Navajo way: lessons for contemporary healing.

    PubMed

    Schneider, Gregory W; DeHaven, Mark J

    2003-01-01

    Given the paradox of the success of modern medical technology and the growing patient dissatisfaction with present-day medicine, critics have called for a reevaluation of contemporary medical practice. This paper offers a phenomenological analysis of traditional Navajo healers and their ceremonies to highlight key aspects of healing. A phenomenological view of medical practice takes into account three key features: the lifeworld, the lived body, and understanding. Because of their closeness to a phenomenological view, traditional Navajo mythology and healing practices offer insight into the healing process. Contemporary physicians can appreciate the phenomenological elements of Navajo healing ceremonies, including the Mountain Chant. Navajo healers help patients make sense of their illnesses and direct their lives accordingly, an outcome available to contemporary practitioners, who are also gifted with the benefits of new technologies. By examining scientific medicine, Navajo healing practices, and phenomenology as complementary disciplines, the authors provide the groundwork for reestablishing a more therapeutic view of health. PMID:12878811

  7. Composition, provenance and source weathering of Mesozoic sandstones from Western-Central Mediterranean Alpine Chains

    NASA Astrophysics Data System (ADS)

    Perri, F.

    2014-03-01

    Forty-two Mesozoic sandstone samples from three different sedimentary successions of the Internal Domains along the Western-Central Mediterranean Alpine Chains (Betic Cordillera, Rif Chain and Calabria-Peloritani Arc) were chemically analyzed to characterize their composition and the degree of weathering in the source area(s). The Rif Chain sandstones have SiO2 contents higher than those of the Calabria-Peloritani Arc and Betic Cordillera sandstones, whereas Al2O3 contents are higher in the Calabria-Peloritani Arc sandstones rather than in the Rif Chain and Betic Cordillera sandstones. The indices of compositional variability (ICV) of the studied samples are generally less than 1, suggesting that the samples are compositionally mature and were likely dominated by recycling. Recycling processes are also shown by the Al-Zr-Ti diagram indicating zircon addition and, thus, recycling processes. The Chemical Index of Alteration (CIA) values are quite homogeneous for the Calabria-Peloritani Arc (mean = 76) and Betic Cordillera sandstones (mean = 55), whereas the Rif Chain sandstones are characterized by CIA values ranging from 54 to 76. The CIW and PIA values are high for all the studied sandstones indicating intense weathering at the source areas. The different values of weathering rates among the studied sandstones may be related to variations of paleoclimatic conditions during the Mesozoic, that further favored recycling processes. Thus, these differences among the studied samples, may be related to an increase in continental palaeoweathering conditions and sediment recycling effects from the Middle Triassic to the earliest Jurassic due to rising humidity. In addition, regional tectonic movements promoted structural changes that allowed sedimentary recycling and subsidence, which in turn caused diagenetic K-metasomatism. These processes could significantly affect the CIW and PIA weathering indices, which likely monitor a cumulative effect, including several cycles of weathering at the source. The source areas are mainly composed of intermediate-felsic rocks with minor, but not negligible, mafic supply, as suggested by provenance proxies.

  8. Sandstone Cliffs in Capitol Reef

    USGS Multimedia Gallery

    Sandstone cliffs in Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  9. Sandstone Cliff in Capitol Reef

    USGS Multimedia Gallery

    A sandstone cliff in Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  10. Sandstone Monolith in Capitol Reef

    USGS Multimedia Gallery

    A sandstone monolith in Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  11. Sandstone Spire in Capitol Reef

    USGS Multimedia Gallery

    A view of a sandstone spire in Capitol Reef National Park. This area, known as the Fruita, is made up of three primary layers. The bottom sandstone layer is known as the Moenkopi Formation and is about 245 million years old. The middle gray-green layer is known as the Chinle Formation and was laid d...

  12. 25 CFR 161.307 - When may a permittee commence grazing on Navajo Partitioned Land?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When may a permittee commence grazing on Navajo... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements 161.307 When may a permittee commence grazing on Navajo Partitioned Land? The permittee may graze on Navajo Partitioned Land on the...

  13. Teaching Dine Language and Culture in Navajo Schools: Voices from the Community.

    ERIC Educational Resources Information Center

    Batchelder, Ann

    Since 1984 the Navajo Nation has mandated instruction in Navajo language and culture in K-12 schools within its boundaries. In 1998-99, a survey and follow-up interviews with 48 individuals in 20 Navajo communities examined community attitudes and beliefs about the value of Navajo language and culture studies and the extent to which the schools

  14. 25 CFR 161.800 - How does the Navajo Nation provide concurrence to BIA?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How does the Navajo Nation provide concurrence to BIA... NAVAJO PARTITIONED LANDS GRAZING PERMITS Concurrence/Appeals/Amendments 161.800 How does the Navajo... Navajo Nation under section 640d-9(e)(1)(A) of the Settlement Act. (b) For any action requiring...

  15. From a Place Deep inside: Culturally Appropriate Curriculum as the Embodiment of Navajo-ness in Classroom Pedagogy

    ERIC Educational Resources Information Center

    Yazzie-Mintz, Tarajean

    2007-01-01

    Three Navajo teachers' conceptions of culturally appropriate curriculum and pedagogy highlight the benefits of reflective practice within different educational and school contexts. Each teacher provides a way of thinking about culturally appropriate curriculum, and its implementation in classroom practice for different Navajo students. The ways in

  16. Collapsing the Fear of Mathematics: A Study of the Effects of Navajo Culture on Navajo Student Performance in Mathematics

    ERIC Educational Resources Information Center

    Fowler, Henry H.

    2010-01-01

    Collapsing the Fear of Mathematics: A Study of the Effects of Navajo Culture on Navajo Student Performance in Mathematics by Henry H Fowler Abstract American schools are in a state of "mediocrity" because of the low expectations in math (National Commission on Excellence in Education, 1983; No Child Left Behind Act of 2001; Duncan, 2009).

  17. Looking after the Land: The Navajo Dryland Environments Laboratory Researches the Environmental Needs of the Navajo Nation.

    ERIC Educational Resources Information Center

    Semken, Steven C.

    1992-01-01

    Describes the formation and operations of the Navajo Dryland Environments Laboratory (NDEL). NDEL, established by the Waste-Management Education and Research Consortium of New Mexico on the campus of Navajo Community College, focuses on environmental geology, hydrology, and resource management of the Colorado Plateau drylands. (DMM)

  18. Diné (Navajo) Ethno- and Archaeoastronomy

    NASA Astrophysics Data System (ADS)

    Chamberlain, Von Del

    The Navajo (Diné) are an Athabascan-speaking people who migrated from the far northwest of America into the desert southwest where they became the largest surviving Native American culture. Three words portray Diné philosophy - beauty, harmony, and balance. Their traditions are rich with astronomical symbolism found in literature, ceremony, iconography, artifacts, rock art, and the sacred landscape. This chapter summarizes Diné astronomical traditions, identification of stars known to be important to the Diné, and how these are depicted on artifacts and rock art.

  19. Late Jurassic weather forecast, Four Corners area: Dry, hot, and partly sunny

    SciTech Connect

    Turner-Peterson, C.E.; Fishman, N.S. )

    1989-09-01

    Interfingering between members of the Upper Jurassic Morrison Formation and inferences based on their various environments of deposition permit interpretation of a persistent paleoclimate during the Late Jurassic in the Colorado Plateau region. Paleoclimate interpretation is based on evaporites in the Tidwell member, at the base of the Morrison; eolian deposits in the Recapture and Bluff Sandstone members; and saline, alkaline-lake deposits (which indicate high evaporation rates) in the Brushy Basin member at the top of the Morrison. Interfingering of these members with all other members of the Morrison Formation implies that a semiarid to arid climate was likely throughout Morrison time. The semiarid to arid interpretation is consistent with the global climatic zone inferred from the paleogeographic/paleotectonic setting. The Four Corners area during the Late Jurassic was in the middle latitudes of the Northern Hemisphere and thus was affected by prevailing westerly winds. A magmatic arc located several hundred kilometers to the west of the Morrison depositional basin may have caused a broad rain-shadow effect, which contributed to a dry continental climate downwind. A typical Late Jurassic day in the Four Corners area is predicted to have been hot and dry, although seasonally heavy rains probably fed intermittent streams that transported sediments into the region. Explosive eruptions of silicic volcanic ash may have darkened the skies episodically, and thus partly sunny would have been a conservative forecast.

  20. Geology and ground water of the Red Lake area, Navajo Indian Reservation, Arizona and New Mexico

    USGS Publications Warehouse

    Akers, J.P.; McClymonds, N.E.; Harshbarger, John William

    1962-01-01

    The Red Lake area in the Navajo Indian Reservation, Arizona and New Mexico, was studied by the U.S. Geological Survey to determine if 1 mgd (mil- lion gallons per day) of water could be obtained for the requirements of a proposed sawmill. Geologic mapping and stratigraphic studies indicated three favorable areas where ground water may be developed. Test holes were drilled under contract in the areas, and pumping tests indicate that 500,000 gpd (gal- lons per day) is available from alluvium along Tohdildonih Wash near Frog Rock, 100,000 gpd is available from the Shinarump member of the Chinle forma- tion and the De Chelly sandstone near Red Lake, and 800,000 gpd is available from alluvium and cinder beds in lapiUi tuff in Buell Park, an eroded diatreme. The diatreme at Buell Park is about 2% miles in diameter. It was formed by several explosions in which lapilli tuff and cinders were erupted. These materials, together with later basaltic intrusive and extrusive rock, now fill the diatreme. The tuff and cinders are water bearing, 'and they receive re- charge from rainwater and snowmelt moving through overlying alluvium and from storage in the De Chelly sandstone which encloses the east half of the diatreme. The quality of water from all areas is suitable for domestic use. However, special treatment may be necessary to make the water suitable for pulp processing.

  1. Navajo coal and air quality in Shiprock, New Mexico

    USGS Publications Warehouse

    Bunnell, Joseph E.; Garcia, Linda V.

    2006-01-01

    Among the Navajo people, high levels of respiratory disease, such as asthma, exist in a population with low rates of cigarette smoking. Air quality outdoors and indoors affects respiratory health. Many Navajo Nation residents burn locally mined coal in their homes for heat, as coal is the most economical energy source. The U.S. Geological Survey and Dine College, in cooperation with the Navajo Division of Health, are conducting a study in the Shiprock, New Mexico, area to determine if indoor use of this coal might be contributing to some of the respiratory health problems experienced by the residents. Researchers in this study will (1) examine respiratory health data, (2) identify stove type and use, (3) analyze samples of coal that are used locally, and (4) measure and characterize air quality inside selected homes. This Fact Sheet summarizes the interim results of the study in both English and Navajo. This Fact Sheet is available in three versions: * English [800-KB PDF file ] * Navajo [computer must have Navajo language fonts installed - 304-KB PDF file] * Image of the Navajo language version [19.8-MB PDF file

  2. Sandstone-body and shale-body dimensions in a braided fluvial system: Salt wash sandstone member (Morrison formation), Garfield County, Utah

    USGS Publications Warehouse

    Robinson, J.W.; McCabea, P.J.

    1997-01-01

    Excellent three-dimensional exposures of the Upper Jurassic Salt Wash Sandstone Member of the Morrison Formation in the Henry Mountains area of southern Utah allow measurement of the thickness and width of fluvial sandstone and shale bodies from extensive photomosaics. The Salt Wash Sandstone Member is composed of fluvial channel fill, abandoned channel fill, and overbank/flood-plain strata that were deposited on a broad alluvial plain of low-sinuosity, sandy, braided streams flowing northeast. A hierarchy of sandstone and shale bodies in the Salt Wash Sandstone Member includes, in ascending order, trough cross-bedding, fining-upward units/mudstone intraclast conglomerates, singlestory sandstone bodies/basal conglomerate, abandoned channel fill, multistory sandstone bodies, and overbank/flood-plain heterolithic strata. Trough cross-beds have an average width:thickness ratio (W:T) of 8.5:1 in the lower interval of the Salt Wash Sandstone Member and 10.4:1 in the upper interval. Fining-upward units are 0.5-3.0 m thick and 3-11 m wide. Single-story sandstone bodies in the upper interval are wider and thicker than their counterparts in the lower interval, based on average W:T, linear regression analysis, and cumulative relative frequency graphs. Multistory sandstone bodies are composed of two to eight stories, range up to 30 m thick and over 1500 m wide (W:T > 50:1), and are also larger in the upper interval. Heterolithic units between sandstone bodies include abandoned channel fill (W:T = 33:1) and overbank/flood-plain deposits (W:T = 70:1). Understanding W:T ratios from the component parts of an ancient, sandy, braided stream deposit can be applied in several ways to similar strata in other basins; for example, to (1) determine the width of a unit when only the thickness is known, (2) create correlation guidelines and maximum correlation lengths, (3) aid in interpreting the controls on fluvial architecture, and (4) place additional constraints on input variables to stratigraphie and fluid-flow modeling. The usefulness of these types of data demonstrates the need to develop more data sets from other depositional environments.

  3. Navajo minettes in the Cerros de las Mujeres, New Mexico

    NASA Astrophysics Data System (ADS)

    Vaniman, D.; Laughlin, A. W.; Gladney, E. S.

    1985-06-01

    The Cerros de las Mujeres in west-central New Mexico are three mafic minette plugs that should be considered part of the Navajo volcanic fields on the central Colorado Plateau. This newly recognized occurrence extends the Navajo volcanic fields to the southeastern margin of the Colorado Plateau, within 45 km of the extensional tectonic setting in which the Mogollon ash-flow tuff cauldrons occur. The Cerros de las Mujeres provide additional evidence for contemporaneous sodic and potassic volcanism within the Navajo volcanic fields.

  4. Diagenesis of Upper Jurassic Norphlet Formation, Mobile and Baldwin Counties and offshore Alabama

    SciTech Connect

    Vaughan, R.L. Jr.; Benson, D.J.

    1988-09-01

    The Upper Jurassic Norphlet Formation is an important deep gas reservoir in Mobile and Baldwin Counties and offshore Alabama. The producing reservoir consists of a well-sorted fine-grained subarkose to arkose. Sedimentological studies indicate this unit was deposited on a broad desert plain in environments ranging from eolian dune and interdune to wadi and beach-shoreface. Diagenetic minerals comprise from 5 to 20% of the bulk volume of the sandstone. Porosity ranges from less than 3% to more than 25% and averages around 10%. Most of the porosity consists of hybrid solution-enlarged intergranular and intragranular pores resulting from the dissolution of cements, framework grains, and grain replacements.

  5. Sandstone Formations in Capitol Reef

    USGS Multimedia Gallery

    Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  6. Jurassic depositional history and vanadium-uranium deposits, slick rock district, Colorado plateau

    NASA Astrophysics Data System (ADS)

    Tyler, N.

    1981-08-01

    The Jurassic interval studied in the Slick Rock vanadium-uranium district consists of the upper units of the San Rafael group (the Summerville formation and the Junction Creek sandstone) and the Tidwell and Salt Wash members of the Morrison formation. The dominantly argillaceous Summerville formation is interpreted as a lacustrine deposit. A salt cast-bearing seven meter thick arenite sequence in the central portions of the Summerville assemblage is inferred to have been deposited in the nearshore and evaporative foreshore setting during a major lacustrine regression. As the Summerville lake dried up, sand dunes migrated across the lacustrine plain. These are now preserved as the eolian Junction Creek sandstone in the southern part of the study area.

  7. Middle Jurassic incised valley fill (eolian/estuarine) and nearshore marine petroleum reservoirs, Powder River Basin

    USGS Publications Warehouse

    Ahlbrandt, T.S.; Fox, J.E.

    1997-01-01

    Paleovalleys incised into the Triassic Spearfish Formation (Chugwater equivalent) are filled with a vertical sequence of eolian, estuarine, and marine sandstones of the Middle Jurassic (Bathonian age) Canyon Springs Sandstone Member of the Sundance Formation. An outcrop exemplifying this is located at Red Canyon in the southern Black Hills, Fall River County, South Dakota. These paleovalleys locally have more than 300 ft of relief and are as much as several miles wide. Because they slope in a westerly direction, and Jurassic seas transgressed into the area from the west there was greater marine-influence and more stratigraphic complexity in the subsurface, to the west, as compared to the Black Hills outcrops. In the subsurface two distinctive reservoir sandstone beds within the Canyon Springs Sandstone Member fill the paleovalleys. These are the eolian lower Canyon Springs unit (LCS) and the estuarine upper Canyon Springs unit (UCS), separated by the marine "Limestone Marker" and estuarine "Brown Shale". The LCS and UCS contain significant proven hydrocarbon reservoirs in Wyoming (about 500 MMBO in-place in 9 fields, 188 MMBO produced through 1993) and are prospective in western South Dakota, western Nebraska and northern Colorado. Also prospective is the Callovian-age Hulett Sandstone Member which consists of multiple prograding shoreface to foreshore parasequences, as interpreted from the Red Canyon locality. Petrographic, outcrop and subsurface studies demonstrate the viability of both the Canyon Springs Sandstone and Hulett Sandstone members as superior hydrocarbon reservoirs in both stratigraphic and structural traps. Examples of fields with hydrocarbon production from the Canyon Springs in paleovalleys include Lance Creek field (56 MMBO produced) and the more recently discovered Red Bird field (300 MBO produced), both in Niobrara County, Wyoming. At Red Bird field the primary exploration target was the Pennsylvanian "Leo sands" of the Minnelusa Formation, and production from the Canyon Springs was not anticipated. Canyon Springs reservoirs are easily bypassed because they are relatively unconsolidated, underpressured, low-resistivity, and difficult to evaluate from petrophysics, drill-stem tests, or well cuttings.

  8. Uranium mining and lung cancer in Navajo men.

    PubMed

    Samet, J M; Kutvirt, D M; Waxweiler, R J; Key, C R

    1984-06-01

    We performed a population-based case-control study to examine the association between uranium mining and lung cancer in Navajo men, a predominantly nonsmoking population. The 32 cases included all those occurring among Navajo men between 1969 and 1982, as ascertained by the New Mexico Tumor Registry. For each case in a Navajo man, two controls with nonrespiratory cancer were selected. Of the 32 Navajo patients, 72 per cent had been employed as uranium miners, whereas no controls had documented experience in this industry. The lower 95 per cent confidence limit for the relative risk of lung cancer associated with uranium mining was 14.4. Information on cigarette smoking was available for 21 of the 23 affected uranium miners; eight were nonsmokers and median consumption by the remainder was one to three cigarettes daily. These results demonstrate that in a rural nonsmoking population most of the lung cancer may be attributable to one hazardous occupation. PMID:6717538

  9. TECHNICAL SUPPORT TO NAVAJO NATION ON URANIUM MINING TENORM WASTES.

    EPA Science Inventory

    Assistance is being provided to the Navajo Nation to establish its own radiation protection standards, radiation action levels, identification of safe drinking water sources, safe disposal of radioactive TENORM wastes from abandoned uranium mines, and to locate and decontaminate ...

  10. Navajo coal and air quality in Shiprock, New Mexico

    USGS Publications Warehouse

    Bunnell, Joseph E.; Garcia, Linda V.

    2006-01-01

    Among the Navajo people, high levels of respiratory disease, such as asthma, exist in a population with low rates of cigarette smoking. Air quality outdoors and indoors affects respiratory health. Many Navajo Nation residents burn locally mined coal in their homes for heat, as coal is the most economical energy source. The U.S. Geological Survey and Dine College, in cooperation with the Navajo Division of Health, are conducting a study in the Shiprock, New Mexico, area to determine if indoor use of this coal might be contributing to some of the respiratory health problems experienced by the residents. Researchers in this study will (1) examine respiratory health data, (2) identify stove type and use, (3) analyze samples of coal that are used locally, and (4) measure and characterize air quality inside selected homes. This Fact Sheet summarizes the interim results of the study in both English and Navajo.

  11. Uranium mining and lung cancer in Navajo men

    SciTech Connect

    Samet, J.M.; Kutvirt, D.M.; Waxweiler, R.J.; Key, C.R.

    1984-06-07

    We performed a population-based case-control study to examine the association between uranium mining and lung cancer in Navajo men, a predominantly nonsmoking population. The 32 cases included all those occurring among Navajo men between 1969 and 1982, as ascertained by the New Mexico Tumor Registry. For each case in a Navajo man, two controls with nonrespiratory cancer were selected. Of the 32 Navajo patients, 72 per cent had been employed as uranium miners, whereas no controls had documented experience in this industry. The lower 95 per cent confidence limit for the relative risk of lung cancer associated with uranium mining was 14.4. Information on cigarette smoking was available for 21 of the 23 affected uranium miners; eight were nonsmokers and median consumption by the remainder was one to three cigarettes daily. These results demonstrate that in a rural nonsmoking population most of the lung cancer may be attributable to one hazardous occupation.

  12. Assistive Technology Provision Within the Navajo Nation

    PubMed Central

    Ripat, Jacquie D.

    2014-01-01

    In this study we explored the factors that affect assistive technology (AT) provision within the Navajo Nation using a qualitative approach to inquiry. Focus groups were held in which AT users discussed their awareness of AT and their need for, use of, and satisfaction with AT devices and services. Twenty-eight individuals who used wheelchairs, orthotics or prosthetics, hearing aids, communication aids, vision aids, and other AT participated in one of seven focus groups. Seven AT providers discussed the facilitators and barriers that affect AT provision. The findings revealed six themes common to both stakeholder groups and two additional themes for AT users. The central theme for AT users centered on (not) feeling understood; the central theme for AT providers revolved around the processes, activities, and roles the providers engaged in at times for different clients. Activities to increase awareness and to promote successful AT provision and satisfaction with AT devices were proposed. PMID:25147224

  13. Navajo: A Century of Progress, 1868-1968.

    ERIC Educational Resources Information Center

    Link, Martin A., Ed.

    The year 1968 marks the 100th anniversary of the signing of the Treaty of Peace between the Navajo tribe and the U.S. Government. The treaty, signed by 29 Navajo headmen and 10 officers of the U.S. Army on June 1, 1968, brought to an end a tragic period of suffering, hardship, deprivation, and exile at the Bosque Redondo, New Mexico. During the

  14. Jurassic Magmatism, Metamorphism and Basin Development in the Pontides: AN Early Black Sea?

    NASA Astrophysics Data System (ADS)

    Okay, A. I.; Sunal, G.; Sherlock, S. C.

    2011-12-01

    The Jurassic system in the circum-Black Sea region is characterized by extensive basic magmatism and deposition of thick clastic and volcano-clastic sequences in the Caucasus, Pontides and the Crimea. Acidic to intermediate calc-alkaline granitoidic rocks also crop out in the Central Pontides in Turkey. Recently we also discovered a Jurassic gneiss-dominated metamorphic series in the Central Pontides, which crop out over a large area of 25 km by 5 km and is in close spatial association with the Jurassic magmatic rocks. The metamorphic rocks, known as the Gene Complex, consist of gneiss, gneissic micaschist, migmatite and minor amounts of amphibolite and marble and are cut by granitic veins tens of meters thick. They are unconformably overlain by the Lower Cretaceous sandstones and conglomerates. The critical mineral paragenesis in the gneisses is cordierite + garnet + biotite + quartz + potassium-feldspar. Based on the mineral chemistry of the critical mineral paragenesis, the peak P-T conditions during the metamorphism have been estimated as 720 40 C temperature and 4 1 kbar pressure. Muscovite and biotite Ar-Ar ages from the gneisses are Late Jurassic (150-140 Ma range). The acidic to intermediate magmatism associated with low pressure - high temperature metamorphism and deposition of over 2000-m-thick clastic and volcanoclastic sedimentary sequences during the Jurassic in the Pontides is best explained by the presence of arc-related basins in the region. However, there is no evidence for continuity between this Paleo-Black Sea basin and the present one, generally considered to be of Early Cretaceous age.

  15. Petrography and diagenesis of Eagle Mills sandstones, subsurface - Northeast Texas and southwest Arkansas

    SciTech Connect

    Dawson, W.C.; Callender, C.A. )

    1991-03-01

    The Eagle Mills Formation (Triassic-Jurassic) has been penetrated by several deep wells (12,000 to 18,000 ft) in northeast Texas and southwest Arkansas. It consists of green, red, and pink conglomeratic lithic arenites and fine- to coarse-grained feldspathic arenites, interbedded with red and greenish gray shales and siltstones. Lithic arenites contain basalt, chert, quartzite, and dolomite rock fragments; plagioclase is the predominant feldspar. All Eagle Mills sandstones have low textural and mineralogic maturities. Eagle Mills red beds and associated intrusive igneous rocks (diabase and basalt dikes and sills) represent the fillings of grabens or rift basins that actively subsided during deposition (in alluvial, fluvial-deltaic, and lacustrine paleoenvironments). Eagle Mills lithic and feldspathic sandstones have undergone a complex diagenetic history, including chlorite cementation (pore linings and pore fillings), compaction, quartz and feldspar overgrowths, dolomite cementation, chloritization and albitization of detrital feldspars, local dissolution of framework grains (igneous lithics and feldspars), precipitation of kaolinite, late Fe-calcite cementation, and saddle dolomite formation. Cement mineralogies are strongly correlative with lithofacies. Lithic sandstones contain the highest frequency of chlorite cements, whereas feldspathic sandstones are preferentially cemented with carbonates and anhydrite; quartz and feldspar overgrowths are ubiquitous. The suite of authigenic minerals in Eagle Mills sandstones records progressive burial into a deep, high-temperature (120-150C), semiclosed, diagenetic regime.

  16. Protecting the Navajo People through tribal regulation of research.

    PubMed

    Brugge, Doug; Missaghian, Mariam

    2006-07-01

    This essay explores the process and issues related to community collaborative research that involves Native Americans generally, and specifically examines the Navajo Nation's efforts to regulate research within its jurisdiction. Researchers need to account for both the experience of Native Americans and their own preconceptions about Native Americans when conducting research about Native Americans. The Navajo Nation institutionalized an approach to protecting members of the nation when it took over Institutional Review Board (IRB) responsibilities from the US Indian Health Service (IHS) in 1996. While written regulations for the Navajo Nation IRB are not dissimilar, and in some ways are less detailed than those of the IHS IRB, in practice the Navajo Nation allows less flexibility. Primary examples of this include not allowing expedited review and requiring prepublication review of all manuscripts. Because of its broad mandate, the Navajo Nation IRB may also require review of some projects that would not normally be subject to IRB approval, including investigative journalism and secondary research about Navajo People that does not involve direct data collection from human subjects. PMID:16909151

  17. A Jurassic mammal from South America.

    PubMed

    Rauhut, Oliver W M; Martin, Thomas; Ortiz-Jaureguizar, Edgardo; Puerta, Pablo

    2002-03-14

    The Jurassic period is an important stage in early mammalian evolution, as it saw the first diversification of this group, leading to the stem lineages of monotremes and modern therian mammals. However, the fossil record of Jurassic mammals is extremely poor, particularly in the southern continents. Jurassic mammals from Gondwanaland are so far only known from Tanzania and Madagascar, and from trackway evidence from Argentina. Here we report a Jurassic mammal represented by a dentary, which is the first, to our knowledge, from South America. The tiny fossil from the Middle to Late Jurassic of Patagonia is a representative of the recently termed Australosphenida, a group of mammals from Gondwanaland that evolved tribosphenic molars convergently to the Northern Hemisphere Tribosphenida, and probably gave rise to the monotremes. Together with other mammalian evidence from the Southern Hemisphere, the discovery of this new mammal indicates that the Australosphenida had diversified and were widespread in Gondwanaland well before the end of the Jurassic, and that mammalian faunas from the Southern Hemisphere already showed a marked distinction from their northern counterparts by the Middle to Late Jurassic. PMID:11894091

  18. Provenance changes for sandstones from the Sierra de los Cuarzos (central Mexico): the possible record of a terrane accretion

    NASA Astrophysics Data System (ADS)

    Palacios García, N. B.; Martini, M.

    2012-04-01

    The Guerrero terrane is composed of Late Jurassic-Early Cretaceous arc successions exposed along the western Pacific margin of Mexico. Several lines of evidence indicate that the Guerrero terrane represents the Mexican leading-edge of the North American plate, which was drifted in the paleo-Pacific domain during Late Jurassic-Early Cretaceous back-arc spreading, and subsequently accreted back to the Mexican continental core before the Albian. In this paper, we present new stratigraphic data and a detailed provenance analysis of sandstones from the Sierra de Los Cuarzos area, which is located in central Mexico, ~50 km to the east of the Guerrero terrane suture belt. In the Sierra de Los Cuarzos is exposed a Mesozoic succession composed of: 1) quartz-rich turbidites grading upward to 2) calcareous slump deposits, which are overlain by 3) volcaniclastic sandstone and scarce conglomerate hosting 20 cm- to 100 m-wide blocks and slabs of basalt. Sandstone provenance and paleocurrent marks indicate that turbidites and slumps deposits were fed by sources from the Mexican continental core. Similar Late Jurassic-Early Cretaceous turbidites and calcareous slump deposits are exposed in the Sierra de Guanajuato, ~50 km to the west of the Sierra de Los Cuarzos area, and are preliminarily correlated with the lower units (1 and 2) of the study area. On the other hand, provenance analysis indicates that volcaniclastic sandstones from unit 3 were principally fed by the arc successions exposed in the Guerrero terrane. The drastic change in provenance of sandstones from the Sierra de los Cuarzos suggests a complex depositional history, characterized by the contribution of distinct supplying sources during the infilling of the basin. In this paper, it is explored the possibility of a syn-tectonic origin for the volcaniclastic rocks of the Sierra de Los Cuarzos, related to the accretion of the Guerrero terrane to the Mexican continental core.

  19. A glimpse of provenance through the diagenetic haze in Smackover sandstones of the Gulf Coast

    SciTech Connect

    Dworkin, S.I. )

    1990-05-01

    Late Jurassic Smackover sandstones deposited in the four interior salt basins of the Gulf Coast have been extensively altered, yet their provenance signature has not been grossly modified on QFL and QmFLt plots. Recalculating framework compositions to account for diagenesis suggests that Smackover sandstones were derived from the Ouachita fold and thrust belt and the interior portion of the North American craton. Differences in framework composition between the four basins result from both diagenesis and provenance. Detrital quartz and rock fragments have been lime modified by diagenesis. The south Texas and Mississippi basin sandstones contain more polycrystalline quartz than the other two basins. Rock fragments in the three eastern basins consist primarily of SRFs and low-grade MRFs; south Texas sandstones contain mostly gneiss and schist. Feldspar composition is controlled by the pore fluid chemistry. The South Texas and Mississippi basins contain potassium-rich K-spar whereas the east Texas and Louisiana basins contain mostly albite. A uniform 6% loss (whole rock) of feldspar can be recognized petrographically in all four basins but this loss does not significantly shift the provenance fields on QFL and QmFLt plots. Mississippi basin sandstones plot primarily in the craton interior provenance field supporting derivation of these sands from the ancestral Mississippi river, East Texas sandstones are also dominated by a cratonic provenance area. Louisiana sandstones plot in the recycled orogen field and were primarily derived from a local source in the Ouachita fold belt. The provenance of south Texas sands was the interior zone of the Ouachitas, as indicated by the presence of high-grade metamorphic rock fragments and Rb-Sr dates of detrital muscovite.

  20. Paleomagnetism of Jurassic Carbonates from Germany

    NASA Astrophysics Data System (ADS)

    Bachtadse, V.; Settles, E. K.; Soffel, H.

    2014-12-01

    Although the distribution of paleomagnetic data for the Jurassic of stable Europe is notorious for its wide spread and lack of any recognizable age control of pole positions it was only recently that the Jurassic has moved closer to the focus of paleomagnetic research (Kent and Irving, 2010; Muttoni et al. 2013). Here we present paleomagnetic data for carbonate rocks of early and late Jurassic age from southern (Franconia and Swabia) and northern Germany. A total of 406 samples from 37 localities in northern Germany and 180 samples from 19 localities in southern Germany were collected and subjected to detailed demagnetization experiments. All localities are dated biostratigraphically covering the Oxfordian to Tithonian (northern Germany) and the Pliensbachian (southern Germany) in time. After removal of a component of magnetization of secondary origin, stable magnetizations could be identified in 176 samples from 17 sites in northern Germany (D=003.2°, I=53.2°, k=79.4, α95=4.5°). Similar directions (D=001.2°, I=43.3°, k=18.6, α95=13.2°) were isolated in 108 sampled from 8 sites of coeval rocks from southern Germany. Positive fold and reversal tests support our interpretation that the resulting mean direction of is of primary origin e.g. late Jurassic in age. Unfortunately, however, the situation for the early Jurassic of southern Germany is less favourable. Here, only 15 samples from 2 sites yielded magnetizations which were interpreted to be of primary origin (D=025.3°, I=59.4°, k=51.0, α95=11.2°) . The resulting paleo north pole positions for the Lower and Upper Jurassic of Germany plot at comparable latitudes (70°N) but are separated in longitude by roughly 60°. This is compatible with the apparent polar wander path proposed by Kent and Irving (2010). Taking into consideration that the only reliable paleopole for the middle Jurassic of stable Europe is indistinguishable from the late Jurassic paleopole lends additional support to the proposed late Jurassic jump connecting the connecting the early/mid Jurassic standstill to the Jurassic/Cretaceous hook of the Kent and Irving (2010) apparent polar wander path.

  1. Jurassic-Neocomian biostratigraphy, North Slope, Alaska

    SciTech Connect

    Mickey, M.B.; Haga, H.

    1985-04-01

    The foraminiferal and palynological biostratigraphy of subsurface Jurassic and Neocomian (Early Cretaceous) age strata from the North Slope were investigated to better define biostratigraphic zone boundaries and to help clarify the correlation of the stratigraphic units in the National Petroleum Reserve in Alaska (NPRA). Through use of micropaleontologic data, eight principal biostratigraphic units have been identified. The Neocomian and Jurassic strata have each been subdivided into four main units.

  2. World petroleum systems with Jurassic source rocks

    SciTech Connect

    Klemme, H.D. )

    1993-11-08

    Fourteen petroleum systems with Upper Jurassic source rocks contain one quarter of the world's discovered oil and gas. Eleven other systems with Lower and Middle Jurassic source rocks presently have a minor but significant amount of discovered oil and gas. The purpose of this article is to review the systems geologically, describe their location in space and time on a continental scale, estimate their relative petroleum system recovery efficiencies, and outline the effect their essential elements and processes have on their petroleum plumbing.

  3. 78 FR 32273 - Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing Permits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... for Navajo Partitioned Lands Grazing Permits authorized by OMB Control Number 1076-0162. This.... Data OMB Control Number: 1076-0162. Title: Navajo Partitioned Lands Grazing Permits, 25 CFR 161....

  4. STEM Summer Academy on the Navajo Reservation

    NASA Astrophysics Data System (ADS)

    Alexander, C. J.

    2012-12-01

    The US Rosetta Project is the NASA contribution to the International Rosetta Mission, an ESA cornerstone mission to comet Churyumov-Gerasimenko. While the project's outreach efforts span multi-media, and a variety of age and ethnic groups, a special emphasis has been made to find a way to provide meaningful outreach to the reservation communities. Because language preservation is an issue of urgent concern to the reservation communities, and because Rosetta, uniquely among NASA missions, has been named after the notion that keys to missing understanding of elements of the ancient past were found in the language on the original Rosetta stone, the US Rosetta Project has embarked upon outreach with a focus on STEM vocabulary in ancient US languages of the Navajo, Hopi, Ojibwe, and other tribal communities as the project expands. NASA image and science are used and described in the native language, alongside lay English and scientific English curriculum elements. Additionally, science (geology/chemistry/botany/physics) elements drawn from the reservation environment, including geomorphology, geochemistry, soil physics, are included and discussed in the native language as much as possible — with their analogs in other planetary environments (such as Mars). In this paper we will report on the most recent Summer Science Academy [2012], a four week summer course for middle school children, created in collaboration with teachers and administrators in the Chinle Unified School District. The concept of the Academy was initiated in 2011, and the first Academy was conducted shortly thereafter, in June 2011 with 14 children, 3 instructors, and a NASA teacher workshop. The community requested three topics: geology, astronomy, and botany. The 2012 Academy built on the curriculum already developed with more robust field trips, addressed to specific science topics, additional quantitative measurements and activities, with more written material for the cultural components from Navajo contributors. In 2012, the Academy was conducted with 45 children and 4 instructors. Following up on lessons learned in previous reports, it is clear that community involvement and buy-in is critical to the success of the program. This means that the US Rosetta Project modified its goals and curriculum to accommodate the teaching desires of teachers in the district, and the capabilities of the medicine men that agreed to participate. The use of NASA material and imagery can be shown to have a positive impact on the accessibility of the overall STEM material. Metrics used in the program will be discussed. Future work to extract STEM language elements to enhance the program will include organized Elder's Round Tables for discussion, and recording, of language with first speakers. Work on this project was supported by NASA at California Institute of Technology/Jet Propulsion Laboratory.

  5. Regional Jurassic geologic framework of Alabama coastal waters area and adjacent Federal waters area

    USGS Publications Warehouse

    Mink, R.M.; Bearden, B.L.; Mancini, E.A.

    1989-01-01

    To date, numerous Jurassic hydrocarbon fields and pools have been discovered in the Cotton Valley Group, Haynesville Formation, Smackover Formation and Norphlet Formation in the tri-state area of Mississippi, Alabama and Florida, and in Alabama State coastal waters and adjacent Federal waters area. Petroleum traps are basement highs, salt anticlines, faulted salt anticlines and extensional faults associated with salt movement. Reservoirs include continental and marine sandstones, limestones and dolostones. Hydrocarbon types are oil, condensate and natural gas. The onshore stratigraphic and structural information can be used to establish a regional geologic framework for the Jurassic for the State coastal waters and adjacent Federal waters areas. Evaluation of the geologic information along with the hydrocarbon data from the tri-state area indicates that at least three Jurassic hydrocarbon trends (oil, oil and gas condensate, and deep natural gas) can be identified onshore. These onshore hydrocarbon trends can be projected into the Mobile area in the Central Gulf of Mexico and into the Pensacola, Destin Dome and Apalachicola areas in the Eastern Gulf of Mexico. Substantial reserves of natural gas are expected to be present in Alabama State waters and the northern portion of the Mobile area. Significant accumulations of oil and gas condensate may be encountered in the Pensacola, Destin Dome, and Apalachicola areas. ?? 1989.

  6. Jurassic sequence stratigraphy of the eastern Gulf Coastal Plain: Applications to hydrocarbon exploration

    SciTech Connect

    Tew, B.H.; Mancini, E.A.; Mink, R.M. )

    1991-03-01

    Based on regional stratigraphic and sedimentologic data, three unconformity-bounded depositional sequences associated with cycles of relative sea-level change and coastal onlap are recognized for Jurassic strata in the eastern Gulf Coastal Plain area. These sequences are designated, in ascending order, the LZAGC (Lower Zuni A Gulf Coast)-3.1, the LZAGC-4.1, and the LZAGC-4.2 sequences and include Callovian through Kimmeridgian Stage strata. An understanding of the relationship of Jurassic reservoirs to sequence stratigraphy can serve as an aid to hydrocarbon exploration in the eastern gulf area. The most extensive and productive Jurassic hydrocarbon reservoirs in the study area occur within the progradational, regressive highstand deposits of the LZAGC-3.1 and LZAGC-4.1 depositional sequences. For example, the majority of Norphlet sandstone reservoirs in the onshore and offshore Alabama area are interpreted to have accumulated in eolian dune, interdune, and wadi (fluvial) depositional environments, which occurred in association with the highstand regressive system of the LZAGC-3.1 sequence. The most important Smackover reservoirs generally consist of partially to completely dolomitized ooid and peloid packstones and grainstones in the upper portion of the unit. These reservoirs occur in subtidal to supratidal, shoaling-upward carbonate mudstone to grainstone cycles in the highstand regressive system of the LZAGC-4.1 sequence. In addition, minor reservoirs that are discontinuous and not well developed are associated with the shelf margin and transgressive systems of the LZAGC-4.1.

  7. Lower Cretaceous and Upper Jurassic oil reservoirs of the updip basement structure play: Southwest Alabama

    SciTech Connect

    Mink, R.M.; Mancini, E.A.

    1995-10-01

    Exploration for Lower Cretaceous and Upper Jurassic reservoirs associated with updip basement structures currently is the most active exploratory oil play in Alabama. High initial flow rates, on the order of hundreds to thousands of barrels of oil per day, are commonly encountered at depths between 8,200 and 14,500 feet. Fifty-one fields have been established and 25 million barrels of oil have been produced from these fields developed in Lower Cretaceous Hosston and Upper Jurassic Haynesville, Smackover, and Norphlet reservoirs. Production from Smackover carbonates began at Toxey field in 1967 and from Haynesville sandstones at Frisco City field in 1986. As of September 1994, Smackover wells averaged 88 barrels of oil per day and Haynesville wells averaged 284 barrels of oil per day. In 1994, production was established in the Norphlet at North Excel field and in the Hosston at Pleasant Home field. Reservoirs in the updip basement structure play cluster in three distinct areas; (1) a western area on the Choctaw ridge complex, (2) a central area on the Conecuh ridge complex, and (3) an eastern area in the Conecuh embayment. Reservoir lithologies include Smackover limestones and dolostones and Hosston, Haynesville, Smackover, and Norphlet sandstones. Hydrocarbon traps are structural or combination traps where reservoirs occur on the flanks or over the crests of basement palohighs. An understanding of the complex reservoir properties and trap relationships is the key to successful discovery and development of Lower Cretaceous and Upper Jurassic oil reservoirs of the updip basement structure play of southwest Alabama.

  8. The Trading Post System on the Navajo Reservation. Staff Report to the Federal Trade Commission.

    ERIC Educational Resources Information Center

    Federal Trade Commission, Los Angeles, CA.

    Since the late 19th century, trading posts have been a prominant feature in Navajo economic life. Today, due to geographic isolation and an absence of economic alternatives, many Navajos are still dependent upon trading posts. This report of a Federal Trade Commission (FTC) investigation details the system on the Navajo Reservation, including the…

  9. A Little History of North American Indians: The Navajos. New Edition.

    ERIC Educational Resources Information Center

    Lipps, Oscar H.

    This reprint of a 1909 volume portrays the life and history of the Navajo people, based on the personal experiences of an unusually enlightened white observer. The first three chapters cover the Navajo's early history, discovery by Spanish explorers, evidence of a prehistoric and possibly ancestral race, and the beauties of the Navajo's rugged…

  10. 40 CFR 147.3400 - Navajo Indian lands-Class II wells.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Navajo Indian lands-Class II wells. 147.3400 Section 147.3400 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) STATE, TRIBAL, AND EPA-ADMINISTERED UNDERGROUND INJECTION CONTROL PROGRAMS Navajo Indian Lands § 147.3400 Navajo...

  11. Peer Group Evaluation of Narrative Competence: A Navajo Example. Working Papers in Sociolinguistics, No. 47.

    ERIC Educational Resources Information Center

    Brady, Margaret

    The narrative performances of Navajo children were examined to determine the ways in which the skills of competently structuring a narrative are informally learned within the peer group. Ten- and eleven-year-old Navajo children, living near Window Rock, Arizona, were evaluated in telling stories about the most traditional figures of Navajo belief,

  12. 25 CFR 700.843 - Permitting procedures for Navajo Nation Lands.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Permitting procedures for Navajo Nation Lands. 700.843 Section 700.843 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing 700.843 Permitting procedures for Navajo Nation Lands. (a)...

  13. 25 CFR 161.802 - How will the Navajo Nation recommend amendments to this part?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How will the Navajo Nation recommend amendments to this... WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Concurrence/Appeals/Amendments 161.802 How will the Navajo Nation recommend amendments to this part? The Resources Committee will have final authority...

  14. The Image of the Scientist through the Eyes of Navajo Children.

    ERIC Educational Resources Information Center

    Monhardt, Rebecca M.

    2003-01-01

    A study of Navajo children's attitude towards scientists asked 94 southern Utah Navajo students in grades 4-6 to draw a scientist. Although many students appeared to have no conception of what a scientist is, the drawings provided unique insights into Navajo students' perceptions, racial and gender sterotypes, and world views. Implications for

  15. 78 FR 23277 - Navajo Nation; Amendment No. 1 to Notice of a Major Disaster Declaration

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-18

    ... SECURITY Federal Emergency Management Agency Navajo Nation; Amendment No. 1 to Notice of a Major Disaster... notice of a major disaster declaration for the Navajo Nation (FEMA-4104-DR), dated March 5, 2013, and... for the Navajo Nation is hereby amended to include the following area among those areas determined...

  16. Students' Perspectives on Navajo Language and Learning: Voices of the Students

    ERIC Educational Resources Information Center

    Shepard, Marlena

    2012-01-01

    To determine if Navajo language classes made a difference in students' lives, thirty Navajo language and culture students were selected to be interviewed. The students selected were those who were in the language and culture programs in the elementary, middle and high school. The focus was to find out the students' perspectives on Navajo

  17. A Little History of North American Indians: The Navajos. New Edition.

    ERIC Educational Resources Information Center

    Lipps, Oscar H.

    This reprint of a 1909 volume portrays the life and history of the Navajo people, based on the personal experiences of an unusually enlightened white observer. The first three chapters cover the Navajo's early history, discovery by Spanish explorers, evidence of a prehistoric and possibly ancestral race, and the beauties of the Navajo's rugged

  18. The Construction of an Intercultural Sensitizer Training Non-Navajo Personnel.

    ERIC Educational Resources Information Center

    Salzman, Michael B.

    1990-01-01

    The Navajo Intercultural Sensitizer consists of 48 "critical incidents" of cross-cultural conflict and possible interpretations, presented in a programed learning format. Initial interpretations of the incidents differed significantly between similarly educated Anglos and Navajos overall, but not between Anglos and younger (under age 30) Navajos.

  19. A quantitative model of ground-water flow during formation of tabular sandstone uranium deposits

    USGS Publications Warehouse

    Sanford, R.F.

    1994-01-01

    Presents a quantitative simulation of regional groundwater flow during uranium deposition in the Westwater Canyon Member and Jackpile Sandstone Member of the Upper Jurassic Morrison Formation in the San Juan basin. Topographic slope, shoreline position, and density contrasts in the lake and pore fluids controlled the directions of flow and recharge-discharge areas. The most important results for uranium ore deposit formation are that regional groundwater discharged throughout the basin, regional discharge was concentrated along the shore line or playa margin, flow was dominantly gravity driven, and compaction dewatering was negligible. A strong association is found between the tabular sandstone uranium deposits and major inferred zones of mixed local and regional groundwater discharge. -from Author

  20. Operation Sandstone: 1948. Technical report

    SciTech Connect

    Berkhouse, L.H.; Hallowell, J.H.; McMullan, F.W.; Davis, S.E.; Jones, C.B.

    1983-12-19

    SANDSTONE was a three-detonation atmospheric nuclear weapon test series conducted during the spring of 1948 at Enewetak Atoll in the Marshall Islands. Report emphasis is on the radiological safety of the personnel. Available records on personnel exposure are summarized.

  1. A New Classification of Sandstone.

    ERIC Educational Resources Information Center

    Brewer, Roger Clay; And Others

    1990-01-01

    Introduced is a sandstone classification scheme intended for use with thin-sections and hand specimens. Detailed is a step-by-step classification scheme. A graphic presentation of the scheme is presented. This method is compared with other existing schemes. (CW)

  2. Preliminary bedrock and surficial geologic map of the west half of the Sanders 30' x 60' quadrangle, Navajo and Apache Counties, northern Arizona

    USGS Publications Warehouse

    Amoroso, Lee; Priest, Susan S.; Hiza-Redsteer, Margaret

    2014-01-01

    The bedrock and surficial geologic map of the west half of the Sanders 30' x 60' quadrangle was completed in a cooperative effort of the U.S. Geological Survey (USGS) and the Navajo Nation to provide regional geologic information for management and planning officials. This report provides baseline geologic information that will be useful in future studies of groundwater and surface water resources, geologic hazards, and the distribution of soils and plants. The west half of the Sanders quadrangle encompasses approximately 2,509 km2 (980 mi2) within Navajo and Apache Counties of northern Arizona and is bounded by lat 3530' to 35 N., long 10930' to 110 W. The majority of the land within the map area lies within the Navajo Nation. South of the Navajo Nation, private and State lands form a checkerboard pattern east and west of Petrified Forest National Park. In the west half of the Sanders quadrangle, Mesozoic bedrock is nearly flat lying except near folds. A shallow Cenozoic erosional basin that developed about 20 Ma in the western part of the map area cut across late Paleozoic and Mesozoic rocks that were subsequently filled with flat-lying Miocene and Pliocene mudstone and argillaceous sandstone and fluvial sediments of the Bidahochi Formation and associated volcanic rocks of the Hopi Buttes volcanic field. The Bidahochi rocks are capped by Pliocene(?) and Pleistocene fluvial sediments and Quaternary eolian and alluvial deposits. Erosion along northeast-southwest-oriented drainages have exposed elongated ridges of Bidahochi Formation and basin-fill deposits that are exposed through shallow eolian cover of similarly oriented longitudinal dunes. Stokes (1964) concluded that the accumulation of longitudinal sand bodies and the development of confined parallel drainages are simultaneous processes resulting in parallel sets of drainages and ridges oriented along the prevailing southwest wind direction on the southern Colorado Plateau.

  3. Upper Jurassic carbonate deposition, Smackover and Buckner Formations, east Texas

    SciTech Connect

    Cooper, S.D.; McGillis, K.A.; Moore, C.H.; Stewart, S.K.; Wilkinson, S.E.

    1983-03-01

    Examination of cores from the upper Smackover Formation from 30 wells in east Texas confirms the presence of a belt of blanket high-energy ooid sandstone throughout much of the area. In the easternmost part of the study area, ooid grainstones grade updip into lower energy lagoonal facies including pellet and Favreina wackestones and packstones. Lower in the Smackover, low-energy skeletal, pellet and oncolite wackestones and packstones dominate. Two cores contain coralgal fragments suggesting nearby reef development. The overlying lower Buckner Formation is composed dominantly of red beds and evaporites deposited in a sabkha setting. Environments and depocenters within the Buckner are thought to have ben partly controlled by movement of the underlying Louann Salt and by rejuvenation of basement structures. Movement along the Mexia-Talco fault system began in Late Jurassic time and may have affected Smackover and Buckner deposition to an as yet undetermined extent. The extent of the influence of the incipient Sabine uplift on deposition in east Texas has not been determined. The major influence of Louann Salt movement on Smackover and Buckner deposition is confined to the western half of the study area. Salt movement began after the close of Smackover time. Withdrawal of Louann Salt into ridges formed a series of strike-trending linear troughs in the western part of the study area. A second linear zone of thickened Buckner section, apparently unrelated to Louann Salt movement, lies to the northeast of the area of salt structures.

  4. Upper Jurassic ramp carbonate and associated evaporite, Neuquen Province, Argentina

    SciTech Connect

    Nickelsen, B.H.; Merrill, D.A.

    1986-05-01

    The Oxfordian La Manga Limestone (10-65 m) and overlying Auquilco Gypsum (315 m maximum thickness) crop out along the west flank of the Neuquen basin, Neuquen Province, Argentina (36/sup 0/40/sup 0/S lat.). The contact with the underlying Lotena Sandstone is gradational, and both formations are cut by the Late Jurassic Araucanian angular unconformity. Seven lithofacies have been identified within sections measured through the entire interval along the northeast to southwest trending, 30-km long Sierra de la Vaca Muerta ridge (38/sup 0/30'-39/sup 0/S). The La Manga Limestone is interpreted as a temperate ramp carbonate that developed over the Lotena Formation siliciclastic shelf. Interpretations of lithofacies from southwest to northeast are: behind-barrier subtidal lagoon with washovers; coral and red algae biostromes; ooid and peloid sand shoals; downslope wackestone and packstone mud mounds; and deep-water carbonate turbidites. A minor regression separates La Manga and Auquilco Formations. Lithofacies of the Auquilco Formation indicate a shallowing-up sequence comprised of initially deep (hundreds of meters) subaqueous evaporite deposition followed by shallow, subtidal carbonate peloidal and shell fragment grainstones and evaporites. Thickness of the subaqueous evaporite gives an order of magnitude estimate of Auquilco basin depths of a few hundred meters at most. The Neuquen basin has an intermediate proportion of carbonate in comparison to relatively carbonate-poor basins to the south and carbonate-rich basins to the north.

  5. Navajo-Hopi Land Commission Renewable Energy Development Project (NREP)

    SciTech Connect

    Thomas Benally, Deputy Director,

    2012-05-15

    The Navajo Hopi Land Commission Office (NHLCO), a Navajo Nation executive branch agency has conducted activities to determine capacity-building, institution-building, outreach and management activities to initiate the development of large-scale renewable energy - 100 megawatt (MW) or larger - generating projects on land in Northwestern New Mexico in the first year of a multi-year program. The Navajo Hopi Land Commission Renewable Energy Development Project (NREP) is a one year program that will develop and market a strategic business plan; form multi-agency and public-private project partnerships; compile site-specific solar, wind and infrastructure data; and develop and use project communication and marketing tools to support outreach efforts targeting the public, vendors, investors and government audiences.

  6. The Scalpel and the Silver Bear. The First Navajo Woman Surgeon Combines Western Medicine and Traditional Healing.

    ERIC Educational Resources Information Center

    Alvord, Lori Arviso; Van Pelt, Elizabeth Cohen

    In this autobiography, Lori Arviso Alvord describes her journey to become the first Navajo woman surgeon and her realization of the benefits of Navajo philosophy to the healing process. Raised on the Navajo reservation by a White mother and a Navajo father and grandmother, Alvord learned to walk in two worlds. Encouraged to get an education, she

  7. A subsurface study of the Denkman sandstone member, Norphlet Formation, hatters Pond field, Mobile County, Alabama

    SciTech Connect

    Young, L.M.; Anderson, E.G.; Baria, L.R. ); Higginbotham, R.S.

    1990-09-01

    Hatters Pond field is in east-central Mobile County in southwestern Alabama and it produces from both the Norphlet and Smackover formations. The structural trap involves salt movement along the west side of the Mobile Fault System that resulted in a faulted salt anticline. The Norphlet Formation of southwestern Alabama consists of red to gray siltstone and pinkish to gray sandstone with conglomerate layers. Three facies have been distinguished within the Norphlet Formation: a lower shale, a red siltstone sequence, and an upper quartzose unit. The thickness of the formation ranges from a feather edge to more than 800 ft (234.8 m) in southwestern Alabama. The Upper Jurassic Denkman Sandstone Member of the Norphlet Formation at Hatters Pond field is a medium- to fine-grained, well-sorted arkosic sandstone between the underlying Norphlet redbed lithofacies and the carbonates of the overlying Smackover Formation. Here, the Denkman Member can be subdivided into a massive upper unit and a low- to high-angle cross-stratified lower unit. The sandstones are quartz-rich with a high percentage of feldspars. The majority of the feldspar grains observed are potassium feldspar. Microcline is usually less altered when compared with other types of feldspar grains. The major types of feldspar replacement include illitization, hematitization, dolomitization, chloritization, calcitization, vacuolization, and anhydritization. Carbonate replacement of feldspars is very abundant, mostly by ferroan dolomite. Rock fragments are not abundant in the Denkman Member, although there is good evidence of a metamorphic/volcanic source area. The sandstones are cemented by dolomite, calcite, anhydrite, and quartz and feldspar overgrowths. The lower Denkman unit is slightly more porous than the upper Denkman unit. The pore-lining authigenic clay, illite, greatly reduces permeability and porosity in these sandstones.

  8. Sedimentology and palaeontology of upper Karoo aeolian strata (Early Jurassic) in the Tuli Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Bordy, Emese M.; Catuneanu, Octavian

    2002-08-01

    The Karoo Supergroup in the Tuli Basin (South Africa) consists of a sedimentary sequence composed of four stratigraphic units, namely the Basal, Middle and Upper units, and Clarens Formation. The units were deposited in continental settings from approximately Late Carboniferous to Middle Jurassic. This paper focuses on the Clarens Formation, which was examined in terms of sedimentary facies and palaeo-environments based on evidence provided by primary sedimentary structures, palaeo-flow measurements and palaeontological findings. Two main facies associations have been identified: (i) massive and large-scale planar cross-bedded sandstones of aeolian origin; and (ii) horizontally and cross-stratified sandstones of fluvial origin. Most of the sandstone lithofacies of the Clarens Formation were generated as transverse aeolian dunes produced by northwesterly winds in a relatively wet erg milieu. Direct evidence of aquatic subenvironments comes from local small ephemeral stream deposits, whereas palaeontological data provide indirect evidence. Fossils of the Clarens Formation include petrified logs of Agathoxylon sp. wood type and several trace fossils which were produced by insects and vertebrates. The upper part of the Clarens Formation lacks both direct and indirect evidence of aquatic conditions, and this suggests aridification that led to the dominance of dry sand sea conditions.

  9. Geographic information system (G.I.S.) research project at Navajo Community College - Shiprock Campus

    SciTech Connect

    Yazzie, R.; Peter, C.; Aaspas, B.; Isely, D.; Grey, R.

    1995-12-31

    The Navajo and Hopi GIS Project was established to assess the feasibility and impact of implementing GIS techology at Tribal institutions. Los Alamos and Lawrence Livermore National Laboratories funded the Navajo and Hopi Geographic Information System (G.I.S.) Project and assigned a mentor from LANL to help guide the project for three summer months of 1995. The six organizations involved were: LANL, LLNL, Navajo Community College, Navajo Nation Land Office, Northern Arizona University and San Juan College. The Navajo Land Office provided the system software, hardware and training. Northern Arizona University selected two students to work at Hopi Water Resource Department. Navajo Community College provided two students and two faculty members. San Juan College provided one student to work with the N.C.C. group. This made up two project teams which led to two project sites. The project sites are the Water Resource Department on the Hopi reservation and Navajo Community College in Shiprock, New Mexico.

  10. Geohydrology and effects of water use in the Black Mesa area, Navajo and Hopi Indian Reservations, Arizona

    USGS Publications Warehouse

    Eychaner, James H.

    1981-01-01

    The main source of water in the 5,400-square-mile Black Mesa area is the N aquifer, which consists of the Navajo Sandstone and underlying Kayenta Formation and Wingate Sandstone. Water is under confined conditions in the central 3,300 square miles. Transmissivity is less than 1,000 feet squared per day. Storage coefficient is less than 0.0004 in the confined part of the aquifer and at least 0.1 in the unconfined part. Recharge is about 13,000 acre-feet per year, and storage at equilibrium, which was before 1965, was at least 180 million acre-feet. Ground-water withdrawals were less than 400 acre-feet per year before 1970 and increased to 5,300 acre-feet per year 1976-1979. By 1980, municipal-supply pumpage is expected to exceed that for a coal-slurry pipeline. Water levels have declined throughout the confined part of the aquifer. Decline of more than 100 feet was calculated for an area of 200 square miles through 1979 and was projected for 440 square miles through 2001. In the unconfined part, project declines averaged less than 1 foot. If pumping for coal slurry stopped, most of the decline would recover within 10 years. (USGS)

  11. Late Jurassic salamandroid from western Liaoning, China.

    PubMed

    Gao, Ke-Qin; Shubin, Neil H

    2012-04-10

    A Jurassic salamander, Beiyanerpeton jianpingensis (gen. et sp. nov.), from a recently found site in western Liaoning Province, China is the earliest known record of Salamandroidea. As a Late Jurassic record of the group, it extends the range of the clade by ~40 Ma. The Late Jurassic taxon is neotenic and represented by exceptionally preserved specimens, including fully articulated cranial and postcranial skeletons and bony gill structures close to the cheek region. The fossil beds, consisting of dark-brown volcanic ash shales of the Upper Jurassic Tiaojishan (Lanqi) Formation (Oxfordian), underlie trachyandesite rocks that have yielded a SHRIMP zircon U-Pb date of 157 ± 3 Ma. The fossiliferous beds are substantially older than the Jehol Group, including the Yixian Formation ((40)Ar/(39)Ar dates of 122-129 Ma), but slightly younger than the Middle Jurassic Daohugou horizon ((40)Ar/(39)Ar date of 164 ± 4 Ma). The early fossil taxon shares with extant salamandroids derived character states, including: separated nasals lacking a midline contact, angular fused to the prearticular in the lower jaw, and double-headed ribs on the presacral vertebrae. In contrast to extant salamandroids, however, the salamander shows a discrete and tooth-bearing palatine, and unequivocally nonpedicellate and monocuspid marginal teeth in large and presumably mature individuals. The finding provides insights into the evolution of key characters of salamanders, and also provides direct evidence supporting the hypothesis that the split between Cryptobranchoidea and Salamandroidea had taken placed before the Late Jurassic Oxfordian time. In this aspect, both paleontological and molecular data now come to agree. PMID:22411790

  12. Tidal influence within Pennsylvanian sandstones

    SciTech Connect

    Archer, A.W. )

    1991-08-01

    Within Pennsylvanian-age strata of the Illinois basin, large-scale linear sand bodies have been previously interpreted as fluvial and deltaic in origin. Nonetheless, analyses of fine-scale sedimentology and bed forms within such sandstones and the associated shales indicate that tidal processes greatly influenced the depositional environments within such lithofacies. Recent work on Mid-Continent Pennsylvanian-age sandstones indicates the occurrence of similar depositional environments. Based upon the pervasive tidal influence observed within such strata, environmental analogs other than fluvial and deltaic bear consideration. In general, tidally influenced estuarine models seem particularly appropriate. Within such settings, the changeover from a fluvially dominated deposystem to tidally influenced estuary occurs during transgressive phases. Despite the tidal influence that can be interpreted from the sedimentology, the strata contain few, if any, marine indicators because of the low salinities that occurred during deposition. Ongoing work in the Mid-Continent indicates that Morrowan, Atokan, Desmoinesian, Missourian, and Virgilian sands share a number of similarities with the tidally influenced environments delineated in the Illinois basin studies. Thus a tidal/estuarine interpretation might be a generalizable model for many Pennsylvanian sandstones. In addition, enhanced understanding of the siliciclastic parts of Mid-Continent cyclothems provides a more useful framework for documentation of carbonate/siliciclastic interrelationships. Oscillations of carbonate/siliciclastic environments may be more readily explainable by climatic cycles rather than by traditionally popular depth-related facies models.

  13. Eruptive conditions and depositional processes of Narbona Pass Maar volcano, Navajo volcanic field, Navajo Nation, New Mexico (USA)

    NASA Astrophysics Data System (ADS)

    Brand, Brittany D.; Clarke, Amanda B.; Semken, Steven

    2009-01-01

    Phreatomagmatic deposits at Narbona Pass, a mid-Tertiary maar in the Navajo volcanic field (NVF), New Mexico (USA), were characterized in order to reconstruct the evolution and dynamic conditions of the eruption. Our findings shed light on the temporal evolution of the eruption, dominant depositional mechanisms, influence of liquid water on deposit characteristics, geometry and evolution of the vent, efficiency of fragmentation, and the relative importance of magmatic and external volatiles. The basal deposits form a thick (5-20 m), massive lapilli tuff to tuff-breccia deposit. This is overlain by alternating bedded sequences of symmetrical to antidune cross-stratified tuff and lapilli tuff; and diffusely-stratified, clast-supported, reversely-graded lapilli tuffs that pinch and swell laterally. This sequence is interpreted to reflect an initial vent-clearing phase that produced concentrated pyroclastic density currents, followed by a pulsating eruption that produced multiple density currents with varying particle concentrations and flow conditions to yield the well-stratified deposits. Only minor localized soft-sediment deformation was observed, no accretionary lapilli were found, and grain accretion occurs on the lee side of dunes. This suggests that little to no liquid water existed in the density currents during deposition. Juvenile material is dominantly present as blocky fine ash and finely vesiculated fine to coarse lapilli pumice. This indicates that phreatomagmatic fragmentation was predominant, but also that the magma was volatile-rich and vesiculating at the time of eruption. This is the first study to document a significant magmatic volatile component in an NVF maar-diatreme eruption. The top of the phreatomagmatic sequence abruptly contacts the overlying minette lava flows, indicating no gradual drying-out period between the explosive and effusive phases. The lithology of the accidental clasts is consistent throughout the vertical pyroclastic stratigraphy, suggesting that the diatreme eruption did not penetrate below the base of the uppermost country rock unit, a sandstone aquifer 360 m thick. By comparison, other NVF diatremes several tens of kilometers away were excavated to depths of 1,000 m beneath the paleosurface (e.g., Delaney PT. Ship Rock, New Mexico: the vent of a violent volcanic eruption. In: Beus SS (ed) Geological society of America Centennial Field Guide, Rocky Mountain Section 2:411-415 (1987)). This can be accounted for by structurally controlled variations in aquifer thickness beneath different regions of the volcanic field. Variations in accidental clast composition and bedding style around the edifice are indicative of a laterally migrating or widening vent that encountered lateral variations in subsurface geology. We offer reasonable evidence that this subsurface lithology controlled the availability of external water to the magma, which in turn controlled characteristics of deposits and their distribution around the vent.

  14. Physical stratigraphy of Swift-Morrison and Kootenai-Colorado depositional sequences in the Late Jurassic-Early Cretaceous overfilled backarc and foreland basins, western Montana

    SciTech Connect

    Meyers, J.H. . Dept. of Geology); O'Malley, P.J. . Dept. of Geosciences)

    1993-04-01

    Late Jurassic-Early Cretaceous sedimentation in western Montana includes two depositional sequences. The older sequence (Swift-Morrison Formations) was deposited in the Sundance foreland basin and ensuing Morrison back-arc basin. The younger sequence (Kootenal Formation-Colorado Group) was deposited in the overfilled early Rocky Mountain foreland basin. Swift strata record coastal onlap and marine progradation over a dissected structural complex (Belt Island) and include a laterally restricted basal conglomerate (0--4 m-thick) representing estuarine paleovalley fill, and an overlying pervasive 16--25 m-thick upward-fining sandstone body dominated by tidal features. To the south, the sandstone body is conformably overlain by distal alluvial-fan and coastal-plain green mudstone, interbedded thin micritic limestone, and red mudstone of the lower and middle Morrison Formation. Morrison red mudstones contain thin sheet sandstones and sparse thick lenticular sandstones, representing northeastward dispersal of detritus in a mud-dominated distal alluvial fan. Northward, the Morrison thins and is mostly green and gray mudstone with thin interbedded sheet sandstone and rare intraformational-pebble-bearing ribbon sandstone. To the south, Kootenai rocks unconformably overlie the Morrison Formation and include a thick basal sandstone deposited in northeast-flowing truck rivers whose courses were controlled by subtle structural topography developed along reactivated basement faults. In the Great Falls area this sandstone (K1-Cutbank of Foster, 1992) may represent distributary channels in a prograding fluvial-dominated delta in the Sunburst sea. Overlying mudstones and thick nodular limestones (K2) represent alluvial-plain sedimentation and paleosol development. Thin shallow-marine sandstone (K3-Sunburst) caps the fluvial-deltaic sequence in the Great Falls area.

  15. Navajo Uranium Education Programs: The Search for Environmental Justice

    ERIC Educational Resources Information Center

    Charley, Perry H.; Dawson, Susan E.; Madsen, Gary E.; Spykerman, Bryan R.

    2004-01-01

    Uranium mining and milling in the Four Corners' area of the American Southwest has had serious negative impacts on American Indian workers, their families, and their communities. In this article, we will examine Navajo education programs which inform citizens about risks and health impacts associated with radiation exposures. Because the Navajo…

  16. Learning to Construct Verbs in Navajo and Quechua

    ERIC Educational Resources Information Center

    Courtney, Ellen H.; Saville-Troike, Muriel

    2002-01-01

    Navajo and Quechua, both languages with a highly complex morphology, provide intriguing insights into the acquisition of inflectional systems. The development of the verb in the two languages is especially interesting, since the morphology encodes diverse grammatical notions, with the complex verb often constituting the entire sentence. While the

  17. The Missing Link in Navajo Indian Economic Development.

    ERIC Educational Resources Information Center

    Billy, Bahe

    Although off-reservation economic development programs have been emphasized in the past, the Navajo Tribe also needs to emphasize on-reservation economic development in order to prevent the loss of well-educated Indian youth who leave frustrating on-reservation Bureau of Indian Affairs (BIA) jobs to aid outside enterprises in the mining of natural

  18. Indian Reservation Labor Markets: A Navajo Assessment and Challenge.

    ERIC Educational Resources Information Center

    Pottinger, Richard

    1985-01-01

    Assesses report by 1983 Commission on Indian Reservation Economies, which links slow economic growth on Indian reservations to lack of education. Contradicts report's conclusions using data from Navajo reservation. Examines apparent federal assumptions regarding reservation economies. Challenges these assumptions and suggests alternative approach

  19. Prospects for the Survival of the Navajo Language: A Reconsideration.

    ERIC Educational Resources Information Center

    Spolsky, Bernard

    2002-01-01

    Discusses endangerment of the Navajo language, blaming schooling, but noting several other factors that weaken language loyalty. Explains that vernacular literacy, traditional and introduced religion, and political structure have failed to establish a counterforce to language loss. Economic changes have led to new living patterns that, together

  20. Navajo Health Authority, Board of Commissioners, Annual Report, June 1977.

    ERIC Educational Resources Information Center

    Navajo Health Authority, Window Rock, AZ.

    Major developments for the Navajo Health Authority (NHA) and the new American Indian School of Medicine (AISOM) during 1976-77 are highlighted in this fifth annual report by NHA commissioners. Developments cited include renovation of the Shiprock Community Center for use by AISOM, last year of funding from the Area Health Education Center…

  1. Career Unit. The Art of Navajo Rug Weaving.

    ERIC Educational Resources Information Center

    Robb, Edna; And Others

    This career exploration instructional unit on Navajo rug weaving is one of several resulting from the rural southwestern Colorado CEPAC Project (Career Education Process of Attitude Change). This unit consists of (1) five unit objectives (to recognize the importance of sheep in the Indians' life, to realize the time required to prepare wool for…

  2. Successful newborn screening for SCID in the Navajo Nation.

    PubMed

    Kwan, Antonia; Hu, Diana; Song, Miran; Gomes, Heidi; Brown, Denise R; Bourque, Trudy; Gonzalez-Espinosa, Diana; Lin, Zhili; Cowan, Morton J; Puck, Jennifer M

    2015-05-01

    Newborn screening (NBS) for severe combined immunodeficiency (SCID) identifies affected infants before the onset of life-threatening infections, permitting optimal treatment. Navajo Native Americans have a founder mutation in the DNA repair enzyme Artemis, resulting in frequent Artemis SCID (SCID-A). A pilot study at 2 Navajo hospitals assessed the feasibility of SCID NBS in this population. Dried blood spots from 1800 infants were assayed by PCR for T-cell receptor excision circles (TRECs), a biomarker for nave T cells. Starting in February 2012, TREC testing transitioned to standard care throughout the Navajo Area Indian Health Service, and a total of 7900 infants were screened through July 2014. One infant had low TRECs and was diagnosed with non-SCID T lymphopenia, while 4 had undetectable TRECs due to SCID-A, all of whom were referred for hematopoietic cell transplantation. This report establishes the incidence of SCID-A and demonstrates effectiveness of TREC NBS in the Navajo. PMID:25762520

  3. Hand involvement in Navajo neurohepatopathy: a case report.

    PubMed

    Cheema, Tahseen A; Swanson, Scott

    2011-06-01

    We report a case of Navajo neurohepatopathy with severe involvement of the hands. It is a progressive sensorimotor neuropathy with distal weakness, areflexia, and reduced sensation in the extremities associated with acral mutilation. The role of possible surgical intervention is demonstrated in this case. PMID:22654708

  4. "Dine Bizaad" (Navajo Language) at a Crossroads: Extinction or Renewal?

    ERIC Educational Resources Information Center

    Benally, AnCita; Viri, Denis

    2005-01-01

    Until about 20 years ago, the Navajo language was one of the most resilient American Indian languages in modern U.S. history. Today, at the dawn of the 21st century, that has all changed. Some changes can be attributed to the normal dynamics of cultural transmission that affect language use. Some others, such as the dramatic shift toward English

  5. Ethnic Identity and Psychosocial Functioning in Navajo Adolescents

    ERIC Educational Resources Information Center

    Jones, Matthew D.; Galliher, Renee V.

    2007-01-01

    The current study assessed associations among theoretically driven measures of ethnic identity and psychosocial adjustment among 137 Navajo adolescents. For both sexes, measures of students' sense of affirmation and belonging to their ethnic heritage emerged as a strong predictor of positive psychosocial functioning. Less-consistent patterns of

  6. Prevalence of Hepatitis A Virus Antibody Among Navajo School Children.

    ERIC Educational Resources Information Center

    Williams, Robert

    1986-01-01

    A serologic investigation of prevalence of immunity to hepatitis A (anti-HAV) was conducted in a rural school adjacent to a Navajo reservation in New Mexico. The results show rates of anti-HAV that are the highest reported at the ages tested in any subpopulation in the United States, comparable only with those in developing countries. (KH)

  7. Decolonizing the Navajo Nation: The Lessons of the Naabaahii

    ERIC Educational Resources Information Center

    Lee, Lloyd L.

    2011-01-01

    This paper discusses ways Dine peoples can use cultural knowledge to rebuild and decolonize the Navajo Nation. In the past, leaders, warriors, and all peoples worked together to sustain their community's way of life. These stories and strategies can be helpful in rectifying and resolving many challenges and problems Dine peoples face in the…

  8. The Navajo Way: From High School to College.

    ERIC Educational Resources Information Center

    Noon, John

    Written for college-bound Navajo high school seniors and dedicated to all Native Americans, this guide presents information relative to preparation for college entrance. The following topics are discussed in detail: (1) choosing a college (financial help, college major, college size, the minority population at college, community size, and personal

  9. Career Unit. The Art of Navajo Rug Weaving.

    ERIC Educational Resources Information Center

    Robb, Edna; And Others

    This career exploration instructional unit on Navajo rug weaving is one of several resulting from the rural southwestern Colorado CEPAC Project (Career Education Process of Attitude Change). This unit consists of (1) five unit objectives (to recognize the importance of sheep in the Indians' life, to realize the time required to prepare wool for

  10. Of Saints and Lamanites: An Analysis of Navajo Mormonism.

    ERIC Educational Resources Information Center

    Pavlik, Steve

    1992-01-01

    Many Navajos have affiliated with the Mormon church because of the inherent place of Native Americans in church doctrine, the church's opposition to alcohol, deterioration of tribal social order, Mormon tolerance of Indian culture, and material benefits of church association, including the Indian Student Placement Program. Contains 55 references.…

  11. Ethnic Identity and Psychosocial Functioning in Navajo Adolescents

    ERIC Educational Resources Information Center

    Jones, Matthew D.; Galliher, Renee V.

    2007-01-01

    The current study assessed associations among theoretically driven measures of ethnic identity and psychosocial adjustment among 137 Navajo adolescents. For both sexes, measures of students' sense of affirmation and belonging to their ethnic heritage emerged as a strong predictor of positive psychosocial functioning. Less-consistent patterns of…

  12. Salinity increases in the navajo aquifer in southeastern Utah

    USGS Publications Warehouse

    Naftz, D.L.; Spangler, L.E.

    1994-01-01

    Salinity increases in water in some parts of the Navajo aquifer in southeastern Utah have been documented previously. The purpose of this paper is to use bromide, iodide, and chloride concentrations and del oxygen-18 and deuterium values in water from the study area to determine if oil-field brines (OFB) could be the source of increased salinity. Mixing-model results indicate that the bromide-to-chloride X 10,000 weight ratio characteristic of OFB in and outside the study area could not be causing the bromide depletion with increasing salinity in the Navajo aquifer. Mixing-model results indicate that a mixture of one percent OFB with 99 percent Navajo aquifer water would more than double the bromide-to-chloride weight ratio, instead of the observed decrease in the weight ratio with increasing chloride concentration. The trend of the mixing line representing the isotopically enriched samples from the Navajo aquifer does not indicate OFB as the source of isotopically enriched water; however, the simulated isotopic composition of injection water could be a salinity source. The lighter isotopic composition of OFB samples from the Aneth, Ratherford, White Mesa Unit, and McElmo Creek injection sites relative to the Ismay site is a result of continued recycling of injection water mixed with various proportions of isotopically lighter make-up water from the alluvial aquifer along the San Juan River. A mixing model using the isotopic composition of the simulated injection water suggests that enriched samples from the Navajo aquifer are composed of 36 to 75 percent of the simulated injection water. However, chloride concentrations predicted by the isotopic mixing model are up to 13.4 times larger than the measured chloride concentrations in isotopically enriched samples from the Navajo aquifer, indicating that injection water is not the source of increased salinity. Geochemical data consistently show that OFB and associated injection water from the Greater Aneth Oil Field are not the source of salinity increases in the Navajo aquifer.

  13. Can Orbital Forcing Help Explain Reconstructed Monsoon Winds for the Early Jurassic?

    NASA Astrophysics Data System (ADS)

    Rowe, C. M.; Oglesby, R. J.; Loope, D. B.; van der Voo, R. J.

    2007-12-01

    Wind-blown sediments provide direct evidence of atmospheric circulation, which is otherwise very difficult to obtain from the geologic record. Eolian sandstones cover large portions of the Colorado Plateau of the southwestern US. These Early Permian through Early Jurassic sandstones reflect dunes that migrated under a distinctive wind regime that apparently varied little in direction through their 100 Myr span. To the north, the dominant winds came from the NE, curving to NW over the southern portion of the outcrops. Basic concepts of climate would suggest that the NE winds are consistent with low latitude trade winds in the northern hemisphere, and the NW winds consistent with cross-equatorial flow induced by a strong summer monsoonal circulation in the southern hemisphere of Pangea. The dunes in the south also reflect a seasonal wind reversal; during much of the year, slightly weaker winds were from the SE. Southernmost outcrops of the sandstones contain abundant trace fossils and slump structures, suggesting they were deposited at the relatively wet, southern edge of an extensive desert. Conventional wisdom, largely based on paleomagnetic evidence, would place the Colorado Plateau along or just north of the equator during the Early Permian, then moving north through the Triassic to lie near 20N by the Early Jurassic. Yet the constancy of the wind regime indicated by the dip directions of the cross-strata suggests that the dunes and the Plateau stayed within the same climatic zone, despite the hypothesized large northward movement of Pangea. The wind regimes recorded by the dunes are consistent with paleogeographic reconstructions of the late Permian, with the Colorado Plateau straddling the equator, but are very much at odds with a northward movement to about 20 N by the early Jurassic. Previous modeling work, including our own, has produced nearly symmetric monsoon circulations (i.e., monsoons of nearly equal strength in each hemisphere) in part due to the use of present-day orbital parameters. These simulations, therefore, represent an orbital state that does not represent the extremal states that may have affected dune migration. To help resolve the discrepancy between the paleomag and paleowind Pangean positions, climate simulations with the NCAR CCSM3 were made using end members for orbital parameters.

  14. Regional porosity trends of the Upper Jurassic Norphlet Formation in southwestern Alabama and vicinity, with comparisons to formations of other basins

    USGS Publications Warehouse

    Schmoker, J.W.; Schenk, C.J.

    1994-01-01

    Sandstone porosity of the Upper Jurassic Norphlet Formation decreases systematically as depth and thermal maturity increase over a wide range. Median porosity is about 25% where equivalent vitrinite reflectance (Ro) is slightly over 0.7% in the northern part of the study area (Clarke County, Mississippi). Median porosity is reduced to 8% where Ro approaches 2.7% in the southern part of the study area. Based on the comparisons at similar Ro levels, median (50th-percentile) Norphlet porosity exceeds porosities of "typical' sandstones in other basins by more than a factor of two throughout the study area. Even the lower (10th-percentile) Norphlet porosities are higher than median porosities of sandstones in general. -from Authors

  15. Discovering the "-Ologies" on the Jurassic Coast

    ERIC Educational Resources Information Center

    Peacock, Alan

    2007-01-01

    The Jurassic Coast is Britain's only natural World Heritage site, a tangible time-line that takes one through 185 million years of history in 95 miles of coast. It provides individuals with a world-famous educational resource and an unrivalled outdoor classroom that has played a key role in the study of earth sciences. The author is keen to ignite

  16. Jurassic stratigraphy of the Wiggins Arch, Mississippi

    SciTech Connect

    Rhodes, J.A.; Maxwell, G.B. )

    1993-09-01

    Mobil and Shell jointly explored the Wiggins arch area in southern Mississippi from 1985 to 1991. The effort concentrated on the Jurassic Norphlet and Smackover formations. Two wells were drilled into Paleozoic crystalline rocks and one well into the Pine Hill formation. Two of these wells were located on the southern side of the Wiggins arch and provide significant data for interpreting Jurassic stratigraphy. The Mobil No. 1 U.S.A. well encountered a complete Jurassic section, but with some significantly different facies than those encountered by wells to the north. A granite wash section is the equivalent to the Frisco City formation previously only found 100 mi to the north-northeast. All 300 ft of Smackover is crystalline dolomite. The Norphlet section is entirely granite wash. The Pine Hill anhydrite is unusually thick and interpreted to be equivalent to the Louann Salt. Correlations to other wells on the Wiggins arch, particularly the Conoco No. 1 Higgins, indicate that the Jurassic can be divided into three transgressive events separated by the Norphlet/Pine Hill and Frisco City/Buckner regressive events.

  17. Jurassic evolution of the Tien-Shan

    SciTech Connect

    Bebeshev, I.I.

    1994-09-01

    Complex studies led to identification of three stages in Jurassic deposits. The stages reflect development periods of the studied deposits. Each stage is represented by a paleogeographic map that indicates the evolution of ancient landforms in the Tien-Shan region in time and space.

  18. Discovering the "-Ologies" on the Jurassic Coast

    ERIC Educational Resources Information Center

    Peacock, Alan

    2007-01-01

    The Jurassic Coast is Britain's only natural World Heritage site, a tangible time-line that takes one through 185 million years of history in 95 miles of coast. It provides individuals with a world-famous educational resource and an unrivalled outdoor classroom that has played a key role in the study of earth sciences. The author is keen to ignite…

  19. Dine bikeyah bik'ah (Navajo oil): An ethnohistory, 1922-1960

    NASA Astrophysics Data System (ADS)

    Chamberlain, Kathleen Patricia

    1998-11-01

    Oil was discovered on the Navajo reservation in 1922, and as a result, the U.S. Department of the Interior pressured Navajos into leasing their lands to develop it. This study reveals that, at first, government officials hoped Navajos would quietly acquiesce, but instead Navajos fought for control. Moreover, oil development served as a basis for tribal debates over such issues as assimilation, land use, and the environment, especially the destruction of grazing areas and sacred sites. Manuscript collections and federal government documents provided the minutes of many tribal council meetings from 1923 to 1960, correspondence between Navajo, Interior Department, and oil company personnel, and royalty and leasing data. Research revealed a tremendous diversity of opinion not only between Navajos and non-Navajos, but between Navajos themselves. Interviews conducted in Farmington, Aztec, Gallup, and Albuquerque, New Mexico, added further complexity and provided local "color." The main difficulty, of course, was locating the Navajo voice and particularly the voices of those not involved in tribal government. A second problem was the paucity of accurate production and royalty documents. Oil company reports were not subject to verification during this period, so it is unlikely that those available provide correct figures. Moreover, oil companies deny possessing archives. This study attempts to balance Navajo and non-Navajo responses to oil development on reservation land from 1922 to 1960 and to suggest future research beyond this period. When dealing with two very diverse cultures, however, there is a tendency to vilify one of them and to examine the other uncritically, perhaps even romantically. Research revealed many complex individuals within both cultures, men and women with varying ambitions and viewpoints. This study presents a tumultuous period in Navajo history and focuses on the successes and failures, abilities and weaknesses of both Navajos and Anglo-Americans.

  20. Geologic map of the Winslow 30 60 quadrangle, Coconino and Navajo Counties, northern Arizona

    USGS Publications Warehouse

    Billingsley, George H.; Block, Debra; Redsteer, Margaret Hiza

    2013-01-01

    The Winslow 30 60 quadrangle encompasses approximately 5,018 km2 (1,960 mi2) within Coconino and Navajo Counties of northern Arizona. It is characterized by gently dipping Paleozoic and Mesozoic strata that dip 1 to 2 northeastward in the southwestern part of the quadrangle and become nearly flat-lying in the northeastern part of the quadrangle. In the northeastern part, a shallow Cenozoic erosional basin developed about 20 million years ago, which subsequently was filled with flat-lying Miocene and Pliocene lacustrine sediments of the Bidahochi Formation, as well as associated volcanic rocks of the Hopi Buttes Volcanic Field. The lacustrine sediments and volcanic rocks unconformably overlie Triassic, Jurassic, and Cretaceous strata. Beginning about early Pliocene time, the Little Colorado River and its tributaries began to remove large volumes of Paleozoic and Mesozoic bedrock from the map area. This erosional development has continued through Pleistocene and Holocene time. Fluvial sediments accumulated episodically throughout this erosional cycle, as indicated by isolated Pliocene(?) and Pleistocene Little Colorado River terrace-gravel deposits on Tucker Mesa and Toltec Divide west of Winslow and younger terrace-gravel deposits along the margins of the Little Colorado River Valley. These gravel deposits suggest that the ancestral Little Colorado River and its valley has eroded and migrated northeastward toward its present location and largely parallels the strike of the Chinle Formation. Today, the Little Colorado River meanders within a 5-km (3-mi) wide valley between Winslow and Leupp, where soft strata of the Chinle Formation is mostly covered by an unknown thickness of Holocene flood-plain deposits. In modern times, the Little Colorado River channel has changed its position as much as a 1.5 km (1 mi) during flood events, but for much of the year the channel is a dry river bed. Surficial alluvial and eolian deposits cover extensive parts of the bedrock outcrops over the entire Winslow quadrangle.

  1. "Still, She Didn't See What I Was Trying to Say": Towards a History of Framing Navajo English in Navajo Written Poetry

    ERIC Educational Resources Information Center

    Webster, Anthony K.

    2010-01-01

    This paper outlines the ways that Navajo poetry was framed in the late 1960s and early 1970s, as "unsophisticated" and non-literary by the introductory materials written by non-Native Americans for collections of Native American poetry. At issue was a view that saw the use of Navajo English, a distinctive vernacular dialect, as a deficient form of

  2. Middle Jurassic non-marine siliciclastic facies in southern central Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Al-Aswad, Ahmad A.

    1995-04-01

    Middle Jurassic deposits of Saudi Arabia show distinct lateral facies variation, where the carbonates in the north are replaced by siliciclastic rocks in the south. In southern central Saudi Arabia, the Middle Jurassic deposits are composed exclusively of siliciclastic rocks, mainly sandstone with minor shale and siltstone, and rare conglomerate. Five stratigraphical sections were measured and studied along the southern Tuwaiq escarpments, where these rocks are well-exposed. A fluvial depositional environment is proposed here for the Middle Jurassic rocks in southern central Saudi Arabia based on sedimentological and petrological evidence. Eight different lithofacies were recognized in these deposits and each is described and interpreted. Cyclic sedimentation is prominent in all the sections studied; the most frequent transition is from medium-coarse pebbly sand to fine sands/silts/muds indicating a transition from sand flat or channel bar deposition, in which the upper flow regime dominates, to overbank deposition, where the lower flow regime prevails. Sandy bedform and downstream-accretion macroforms are the most common fluvial architectural elements. A braided stream system is the most appropriate model for these rocks, but the geomorphology of the streams was not constant in either space or time. However, the streams were braided most of the time, especially in the vicinity of the upstream source area in the southern highlands, and they changed their morphology gradually northward to become more sinuous, but never reached the stage where they become true meandering rivers. The change in stream morphology affected the distribution of fluviual facies and resulted in the presence of a proximal fluvial facies dominating in the south and a distal facies prevailing in the north. The streams flowed from south to north with little or no contribution from east-flowing tributaries. At this time, the Central Arabian Arch was a negative, submerged structural feature subsiding under the accumulating shelf carbonate sediments, whereas the Hadramaut and Mukalla Arches were positive features controlling the sedimentation pattern in southern central Arabia. Although the Middle Jurassic rocks, both in the north and in the south, form a slightly diachronous, contiguous sedimentary body, they differ from each other significantly. Therefore, it is recommended here that the Middle Jurassic siliciclastic facies in southern central Saudi Arabia be separated from the Dhruma Formation and be recognized as a new stratigraphical unit with formational rank.

  3. South and North Barents Triassic-Jurassic total petroleum system of the Russian offshore Arctic

    USGS Publications Warehouse

    Lindquist, Sandra J.

    1999-01-01

    One major gas-prone petroleum system characterizes the sparsely explored South and North Barents Basin Provinces of the Russian Arctic in the eastern Barents Sea. More than 13 billion barrels of oil equivalent (79 trillion cubic feet of gas) known ultimately recoverable gas reserves in seven fields were sourced from Triassic marine and continental shales and stored in Jurassic (97%) and Triassic (3%) marine and continental sandstone reservoir rocks. The basins contain 18-20 kilometers of pre-Upper Permian carbonate and post-Upper Permian siliciclastic sedimentary fill. Late Permian-Triassic(?) rifting and subsidence resulted in the deposition of as much as 9 kilometers of Triassic strata, locally injected with sills. Rapidly buried Lower Triassic source rocks generated hydrocarbons as early as Late Triassic into stratigraphic traps and structural closures that were modified periodically. Thermal cooling and deformation associated with Cenozoic uplift impacted seal integrity and generation processes, modified traps, and caused gas expansion and remigration.

  4. Characterization of Petroleum Residue in the Entrada Sandstone, Colorado National Monument

    USGS Publications Warehouse

    Lillis, Paul G.; King, J. David

    2007-01-01

    Introduction As part of the U.S. Geological Survey's (USGS) petroleum resource assessment of the Uinta-Piceance Province, Colorado and Utah, in 2000 (USGS Uinta-Piceance Assessment Team, 2003), some 170 oils, oil stains, and oil seeps were geochemically characterized and divided into genetic types (Lillis and others, 2003). Recognized oil types include Minturn, Phosphoria, Grassy Trail Creek, Mancos, Mesaverde, and Green River. Subsequent to that study, the existence and general locality of petroleum residue in the Middle Jurassic Entrada Sandstone in Colorado National Monument (CNM) was brought to the attention of the authors (Scott and others, 2001). Because the analysis of such non-commercial petroleum deposits commonly yields valuable regional resource-trend information, we collected and characterized the reported CNM petroleum residue and compared the results with identified oil types in the Uinta-Piceance Province. Three samples of Entrada Sandstone with petroleum residue were collected near Little Park Road along the south edge of the CNM in sec.20, T.12S., R.101W. The approximate extent of the petroleum staining was determined by field testing with solvent, and the stains appear to be restricted to the upper part of the 'board beds' unit (informal name, Scott and others, 2001) of the Entrada Sandstone between the two fault traces of the Glade Park fault.

  5. Snow-covered Sandstone at Bryce Canyon

    USGS Multimedia Gallery

    Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandstone that forms their base. Bryce Canyon is also home to large numbe...

  6. Sandstone Strata in Capitol Reef National Park

    USGS Multimedia Gallery

    A detail view of some sandstone strata within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  7. Field manual for the collection of Navajo Nation streamflow-gage data

    USGS Publications Warehouse

    Hart, Robert J.; Fisk, Gregory G.

    2014-01-01

    The Field Manual for the Collection of Navajo Nation Streamflow-Gage Data (Navajo Field Manual) is based on established (standard) U.S. Geological Survey streamflow-gaging methods and provides guidelines specifically designed for the Navajo Department of Water Resources personnel who establish and maintain streamflow gages. The Navajo Field Manual addresses field visits, including essential field equipment and the selection of and routine visits to streamflow-gaging stations, examines surveying methods for determining peak flows (indirect measurements), discusses safety considerations, and defines basic terms.

  8. Navajo Generating Station and Air Visibility Regulations: Alternatives and Impacts

    SciTech Connect

    Hurlbut, D. J.; Haase, S.; Brinkman, G.; Funk, K.; Gelman, R.; Lantz, E.; Larney, C.; Peterson, D.; Worley, C.; Liebsch, E.

    2012-01-01

    Pursuant to the Clean Air Act, the U.S. Environmental Protection Agency (EPA) announced in 2009 its intent to issue rules for controlling emissions from Navajo Generating Station that could affect visibility at the Grand Canyon and at several other national parks and wilderness areas. The final rule will conform to what EPA determines is the best available retrofit technology (BART) for the control of haze-causing air pollutants, especially nitrogen oxides. While EPA is ultimately responsible for setting Navajo Generating Station's BART standards in its final rule, it will be the U.S. Department of the Interior's responsibility to manage compliance and the related impacts. This study aims to assist both Interior and EPA by providing an objective assessment of issues relating to the power sector.

  9. Coping with arsenic-based pesticides on Dine (Navajo) textiles

    NASA Astrophysics Data System (ADS)

    Anderson, Jae R.

    Arsenic-based pesticide residues have been detected on Arizona State Museum's (ASM) Dine (Navajo) textile collection using a handheld portable X-ray (pXRF) spectrometer. The removal of this toxic pesticide from historic textiles in museums collections is necessary to reduce potential health risks to Native American communities, museum professionals, and visitors. The research objective was divided into three interconnected stages: (1) empirically calibrate the pXRF instrument for arsenic contaminated cotton and wool textiles; (2) engineer an aqueous washing treatment exploring the effects of time, temperature, agitation, and pH conditions to efficiently remove arsenic from wool textiles while minimizing damage to the structure and properties of the textile; (3) demonstrate the devised aqueous washing treatment method on three historic Navajo textiles known to have arsenic-based pesticide residues. The preliminary results removed 96% of arsenic from a high arsenic concentration (~1000 ppm) textile opposed to minimal change for low arsenic concentration textiles (<100 ppm).

  10. Depositional setting of the Jurassic Haynesville seismic sequence in the Apalachicola Basin, northeastern Gulf of Mexico

    SciTech Connect

    Dobson, L.M.; Buffler, R.T. )

    1990-05-01

    Seismic and well data from the northeastern Gulf of Mexico were used to define the seismic stratigraphy, geologic history, and depositional setting of the Jurassic (Kimmeridgian) Haynesville sequence in the Apalachicola basin. The data show that Haynesville clastic sedimentation updip was coeval with Haynesville carbonate deposition downdip. The regional Jurassic seismic stratigraphic framework includes, in ascending order, the Louann Salt Norphlet-Smackover, Haynesville, and Cotton Valley sequences. In the vicinity of Destin dome, wells have penetrated Haynesville sandstones, shales, and anhydrites. These clastics correlate with low amplitude, low-continuity reflections that characterize the Haynesville over a broad area updip. Similar reflections within the overlying (Tithonian-earliest Berriasian) Cotton Valley clastic sequence make seismic definition of the top Haynesville sequence boundary difficult updip. As Haynesville clastics are replaced by carbonates downdip, a high amplitude reflection marks the top of the sequence. Haynesville carbonates conformably overlie (Oxfordian) Smackover carbonates in the basin center, and the lower sequence boundary cannot be defined where disrupted by growth faults associated with early movement of the (Callovian ) Louann Salt. Sigmoid clinoforms document Haynesville shelf margin development Seismic facies also include oblique clinoforms that prograde eastward into the basin from the Southern Platform and Middle Ground Arch. No wells penetrate this facies. Mapping of the seismic facies and correlation with well data suggest a depositional setting for the Haynesville sequence in which influx of terrigenous clastics probably derived from adjacent land areas to the north and northeast filled a broad lagoon behind a carbonate shelf margin.

  11. Bird-like anatomy, posture, and behavior revealed by an early jurassic theropod dinosaur resting trace

    USGS Publications Warehouse

    Milner, A.R.C.; Harris, J.D.; Lockley, M.G.; Kirkland, J.I.; Matthews, N.A.

    2009-01-01

    Background: Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb. Methodology/Principal Findings: Here we describe a well-preserved theropod trackway in a Lower Jurassic (???198 millionyear- old) lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity. Conclusions/Significance: The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods.

  12. Sequence stratigraphy of middle and upper Jurassic strata of Southwestern Alabama

    SciTech Connect

    Wade, W.J.; Moore, C.H. Jr. )

    1993-09-01

    Middle and Upper Jurassic systems tracts of southwestern Alabama differ from those of the western Gulf rim, showing: (1) profound influence of antecedent topography; (2) low early subsidence rates; and (3) greater clastic influx from adjacent uplands. Werner Anhydrite and Louann Salt represent the earliest marine incursion onto the Gulf rim following initial rifting; they onlap upper Paleozoic basement and garben-filling Eagle Mills red beds. Because basin-wide evaporative drawdowns overprint even higher order eustatic sea level changes, transgressive systems tracts (TST) and highstand systems tracts (HST) are indistinguishable. Anhydrite and shale caps accumulated via interstratal halite dissolution. Oxfordian Norphlet siliciclastics form a continental lowstand systems tract as illustrated by abrupt contact with underlying marine evaporites without intervening progradational marginal marine facies. Marine-reworked uppermost Norphlet sandstone marks the base of a subsequent TST, which includes overstepping lower Smackover lithofacies (laminated mudstone, algal-laminated mudstone, and pellet wackestone). The upper Smackover HST is characterized by formation of rimmed shelves upon which algal mounds and aggrading ooid grainstone parasequences accumulated. Shallow lagoonal carbonate and evaporite saltern deposition occurred behind ooid shoals; fine-grained siliciclastics accumulated in updip areas. Equivalents of Smackover A, Smackover B, Bossier, and Gilmer sequences are largely masked by influx of Haynesville and Cotton Valley continental clastics. Lack of biostratigraphic data, a consequence of restricted fauna, precludes useful age assignments for these sequences in Alabama. Middle and Upper Jurassic systems tracts of southwestern Alabama are regionally atypical and cannot serve as a model for Gulf-wide sequences.

  13. Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace

    PubMed Central

    Milner, Andrew R. C.; Harris, Jerald D.; Lockley, Martin G.; Kirkland, James I.; Matthews, Neffra A.

    2009-01-01

    Background Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb. Methodology/Principal Findings Here we describe a well-preserved theropod trackway in a Lower Jurassic (∼198 million-year-old) lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity. Conclusions/Significance The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods. PMID:19259260

  14. Recoverable natural gas reserves from Jurassic Norphlet Formation, Alabama coastal waters

    SciTech Connect

    Mancini, E.A.; Mink, R.M.; Bearden, B.L.; Hamilton, R.P.

    1987-09-01

    To date, 11 Norphlet gas fields have been established in offshore Alabama. These fields are part of a deep Jurassic gas trend that extends across southern Mississippi and Alabama into the Gulf of Mexico. Recoverable gas reserves of 4.9-8.1 tcf are estimated for the Norphlet Formation in Alabama's coastal waters. Proven gas reserves are estimated to be 3.7-4.6 tcf and potential reserves are estimated to be 1.2-3.5 tcf. The natural gas is trapped in a series of generally east-west-trending salt anticlines. The mechanism of structure formation appears to be salt flowage that has formed broad, low-relief anticlines, most of which are faulted, and many of which are related to small-scale growth faults. Salt movement is the critical factor in the formation of these petroleum traps. The primary Norphlet reservoir lithofacies are eolian dune and interdune sandstones that range in thickness from 140 to over 600 ft in Alabama's coastal waters. Gas pay can exceed 280 ft in thickness. Porosity is principally secondary, developed as a result of decementation and grain dissolution. Jurassic Smackover algal carbonate mudstones were the main source for the Norphlet hydrocarbons. The seal for the gas is the nonpermeable upper portion of the Norphlet Formation. The overlying lower Smackover carbonates are also nonpermeable and may serve as part of the seal.

  15. Didactyl Tracks of Paravian Theropods (Maniraptora) from the ?Middle Jurassic of Africa

    PubMed Central

    Mudroch, Alexander; Richter, Ute; Joger, Ulrich; Kosma, Ralf; Id, Oumarou; Maga, Abdoulaye

    2011-01-01

    Background A new dinosaur tracksite from ?Middle Jurassic sediments of the Irhazer Group on the plains of Agadez (Rep. Niger, northwest Africa) revealed extraordinarily well preserved didactyl tracks of a digitigrade bipedal trackmaker. The distinct morphology of the pes imprints indicates a theropod trackmaker from a paravian maniraptoran closely related to birds. Methodology/Principal Findings The early age and the morphological traits of the tracks allow for description of the new ichnotaxon Paravipus didactyloides. A total of 120 tracks are assigned to 5 individual trackways. The medium-sized tracks with an average footprint length of 27.5 cm and footprint width of 23.1 cm are deeply imprinted into the track bearing sandstone. Conclusions/Significance A comparison with other didactyl tracks gives new insights into the foot morphology of advanced maniraptoran theropods and contributes to knowledge of their evolutionary history. The new ichnotaxon takes an important position in the ichnological fossil record of Gondwana and the mid-Jurassic biota worldwide, because it is among the earliest known records of paravian maniraptorans and of didactyl theropod tracks from Africa. PMID:21339816

  16. Norphlet formation (Upper Jurassic) of southwestern and offshore Alabama: environments of deposition and petroleum geology

    SciTech Connect

    Mancini, E.A.; Bearden, B.L.; Mink, R.M.; Wilkerson, R.P.

    1985-06-01

    Upper Jurassic Norphlet sediments in southwestern and offshore Alabama accumulated under arid climatic conditions. The Appalachian Mountains of the eastern United States extended into southwestern Alabama to provide a barrier for air and water circulation during the deposition of the Norphlet Formation. These mountains produced topographic conditions that contributed to the arid climate, and they affected sedimentation. Norphlet paleogeography in southwestern Alabama was dominated by a broad desert plain, rimmed to the north and east by the Appalachians and to the south by a developing shallow sea. The desert plain extended westward into eastern and central Mississippi. Norphlet hydrocarbon potential in southwestern and offshore Alabama is excellent; six oil and gas fields already have been established. Petroleum traps discovered to date are primarily structural traps involving salt anticlines, faulted salt anticlines, and extensional fault traps associated with salt movement. Reservoir rocks consist primarily of quartz-rich sandstones that are eolian, wadi, and marine in origin. Porosity is principally secondary (dissolution) with some intergranular porosity. Smackover algal carbonate mudstones were probably the source for the Norphlet hydrocarbons. Jurassic oil generation and migration probably were initiated in the Early Cretaceous.

  17. Jurassic hydrocarbon exploration of southern Florida

    SciTech Connect

    Mitchell-Tapping, H.J.

    1994-09-01

    South Florida Jurassic exploration has been overlooked as a viable exploration target due to lack of data and plate-tectonics application. In Florida, {open_quotes}basement{close_quotes} is defined as crystalline, igneous, metamorphic, and unmetamorphosed sediments of Paleozoic age. Age-dating of zircons has proven that the Florida lower Paleozoic terrane is not akin to that of North America but is part of the West African Guinean shield. Previous published reconstructions of late Paleozoic fits of crustal plates and continents have failed to account for the differences in peninsula Florida basement and the geologic and tectonic continuities of peninsula Florida, Yucatan, Cuba, Hispaniola, and Bahamas. Pre-Atlantic reconstruction of the Gulf of Mexico in this study proposes that there was a Florida connection to Yucatan-Cuba-Africa during the Triassic. This reconstruction also shows that the Jurassic sediments that are well known in the northern Gulf Coast should have been deposited in similar depositional environments in southern Florida. Deep drilling on the Florida peninsula has confirmed this hypothesis. By using plate tectonic reconstruction based on the rising of the North Atlantic Ocean and evidence from petrology of basement samples from deep wells together with petrographic analyses of Jurassic sediments, a Smackover-equivalent exploration play can be developed. Petrographic and petrophysical analysis of these wells that have encountered Jurassic marine shales, anhydrite, dolomite, carbonate, and elastic sediments has determined that these sediments are from shallow-water subtidal, tidal, intertidal, and supratidal environments. Excellent gas shows, oil stain in the pores and high TOC values in the marine shales, indicate that large accumulations of hydrocarbon are present.

  18. The Lowell Observatory Navajo-Hopi Astronomy Outreach Program

    NASA Astrophysics Data System (ADS)

    Herrmann, K. A.; Hunter, D. A.; Bosh, A. S.; Johnson, M.; Schindler, K.

    2012-08-01

    We present an overview of the Lowell Observatory Navajo-Hopi Astronomy Outreach Program, which is modeled after the ASP's Project ASTRO (Richter & Fraknoi 1994). Since 1996, our missions have been (1) to use the inherent excitement about the night sky to help teachers get Navajo and Hopi students excited about science and education, and (2) to help teachers of Navajo and Hopi students learn about astronomy and hands-on activities so that they will be better able to incorporate astronomy in their classrooms. Lowell astronomers pair up for a school year with an elementary or middle school (5th-8th grade) teacher and make numerous visits to their teachers' classes, partnering with the educators in leading discussions linked with hands-on activities. Lowell staff also work with educators and amateur astronomers to offer evening star parties that involve the family members of the students as well as the general community. Toward the end of the school year, teachers bring their classes to Lowell Observatory. The classes spend some time exploring the Steele Visitor Center and participating in tours and programs. They also voyage to Lowell's research facility in the evening to observe at two of Lowell's research telescopes. Furthermore, we offer biennial teacher workshops in Flagstaff to provide teachers with tools, curricula materials, and personalized training so that they are able to include astronomy in their classrooms. We also work with tribal educators to incorporate traditional astronomical knowledge. Funding for the program comes from many different sources.

  19. A gestural account of the velar fricative in Navajo.

    PubMed

    Iskarous, Khalil; McDonough, Joyce; Whalen, D H

    2012-05-01

    Using the framework of Articulatory Phonology, we offer a phonological account of the allophonic variation undergone by the velar fricative phoneme in Navajo, a Southern or Apachean Athabaskan language spoken in Arizona and New Mexico. The Navajo velar fricative strongly coarticulates with the following vowel, varying in both place and manner of articulation. The variation in this velar fricative seems greater than the variation of velars in many well-studied languages. The coronal central fricatives in the inventory, in contrast, are quite phonetically stable. The back fricative of Navajo thus highlights 1) the linguistic use of an extreme form of coarticulation and 2) the mechanism by which languages can control coarticulation. It is argued that the task dynamic model underlying Articulatory Phonology, with the mechanism of gestural blending controlling coarticulation, can account for the multiplicity of linguistically-controlled ways in which velars coarticulate with surrounding vowels without requiring any changes of input specification due to context. The ability of phonological and morphological constraints to restrict the amount of coarticulation argues against strict separation of phonetics and phonology. PMID:24765216

  20. A gestural account of the velar fricative in Navajo

    PubMed Central

    ISKAROUS, KHALIL; MCDONOUGH, JOYCE; WHALEN, D. H.

    2013-01-01

    Using the framework of Articulatory Phonology, we offer a phonological account of the allophonic variation undergone by the velar fricative phoneme in Navajo, a Southern or Apachean Athabaskan language spoken in Arizona and New Mexico. The Navajo velar fricative strongly coarticulates with the following vowel, varying in both place and manner of articulation. The variation in this velar fricative seems greater than the variation of velars in many well-studied languages. The coronal central fricatives in the inventory, in contrast, are quite phonetically stable. The back fricative of Navajo thus highlights 1) the linguistic use of an extreme form of coarticulation and 2) the mechanism by which languages can control coarticulation. It is argued that the task dynamic model underlying Articulatory Phonology, with the mechanism of gestural blending controlling coarticulation, can account for the multiplicity of linguistically-controlled ways in which velars coarticulate with surrounding vowels without requiring any changes of input specification due to context. The ability of phonological and morphological constraints to restrict the amount of coarticulation argues against strict separation of phonetics and phonology. PMID:24765216

  1. Bedrock aquifers in the northern San Rafael Swell area, Utah, with special emphasis on the Navajo Sandstone

    USGS Publications Warehouse

    Hood, J.W.; Patterson, D.J.

    1984-01-01

    The northern San Rafael Swell area in southeastern Utah includes about 2,880 square miles (7,460 square kilometers) and ranges in altitude from about 3,290 to 7,921 feet (1,195 to 2,414 meters). Precipitation, the main source of water in the area, ranges from slightly less than 6 inches (152 millimeters) to slightly more than 12 inches (305 millimeters).

  2. Bedrock aquifers in the lower Dirty Devil River basin area, Utah, with special emphasis on the Navajo sandstone

    USGS Publications Warehouse

    Hood, J.W.; Danielson, T.W.

    1981-01-01

    The lower Dirty Devil River basin area in southeastern Utah has an area of about 4,300 square miles (11,140 square kilometers) and ranges in altitude from about 3,700 to more than 11,000 feet (1,130 to 3,350 meters) above mean sea level. Precipitation, the main source of water in the area, ranges from slightly less than 6 inches (152 millimeters) per year in the lowlands to more than 30 inches per year (762 millimeters) in the Henry Mountains and along the western boundary.

  3. Blueberries on Earth and Mars: Some Correlations Between Andean Paleosols, Geothermal Pipes in Navajo Sandstone and Terra Meridiani on Mars

    NASA Astrophysics Data System (ADS)

    Mahaney, W. C.; Milner, M. W.; Netoff, D. I.; Dohm, J. M.; Sodhi, R. N. S.; Aufreiter, S.; Hancock, R. G. V.; Bezada, M.; Kalm, V.; Malloch, D.

    2006-03-01

    The origin of "blueberries" on Mars and their relationship to similar concretionary forms on Earth invokes a process of variable redox conditions in underground fluids. The possible role of microorganisms in the origin of bluberries opens an avenue for biological investigations.

  4. Iron Isotopes in Spherical Hematite and Goethite Concretions from the Navajo Sandstone (Utah, USA): A Prospective Study for "Martian Blueberries"

    NASA Astrophysics Data System (ADS)

    Busigny, V.; Dauphas, N.

    2006-03-01

    Iron isotopes of terrestrial hematite and goethite concretions provide clues on fluid transport, reservoir sizes, redox variations and biotic versus abiotic processes. This opens several avenues of research for future work on Martian blueberries.

  5. Middle Jurassic Oseberg delta, northern North Sea: A sedimentological and sequence stratigraphic interpretation

    SciTech Connect

    Muto, T.; Steel R.J.

    1997-07-01

    The Aalenian Oseberg Formation (0-80 m thick) is an important reservoir unit in the Middle Jurassic Brent Group in the northern North Sea, consisting of multiple sets of sandy Gilbert-type deltas. Small-scale (1.5-10 m) fining-upward units seen in the gamma-ray log correspond with individual delta sets, as independently confirmed by steepening-upward trends seen in the dip log. Within each set, the steep foreset slopes typically show thinly bedded sandstone facies (avalanche grain flows), whereas the lower foreset slopes, toesets, and bottomsets are formed largely by massive sandstone facies (sandy debris flows). On an intermediate scale (up to 40 m), the gamma-ray logs show both fining-upward and coarsening-upward trends through stacked delta sets, and these trends, traceable between wells, are interpreted in terms of decelerating and accelerating rates of relative sea level rise, respectively. The relative abundance of the sandy debris-flow deposits reflects a periodic and significant instability of the delta`s upper foreset slope, probably during times of increased water depth in front of the delta. The normal progradation of individual Gilbert-type sets, however, is likely to have been along a subhorizontal topography during periods of little or no change in water depth. The long-term change to produce the observed vertical stacking of deltaic sets was one of a generally rising relative sea level.

  6. Model for isopaching Jurassic-age Norphlet Formation in Mobile Bay, Alabama area

    SciTech Connect

    Torres, L.F.

    1989-03-01

    Deep gas was discovered in the Norphlet Sandstone of Mobile Bay Alabama in 1979. Sixteen wells, of which Exxon Company, U.S.A. has had an interest in eight, have tested gas from depths greater than 20,000 ft and at an average rate of 19 million ft/sub 3/ of gas per day. The dominant structural features in Mobile Bay are large east-west-trending salt-supported anticlines associated with salt pull-apart listric normal faulting. Throws on these faults measure up to 1000 ft. Individual structures have dimensions as large as 15 mi in an east-west strike direction and 8 mi in a north-south dip direction. The Jurassic age (Callovian) Norphlet of Mobile Bay is characterized by eolian dune sand deposits up to 700 ft thick. An important factor affecting future development drilling is the accurate prediction of reservoir thickness. This presentation shows that an integrated study of seismic and well data has facilitated the development of a geological model for isopaching the Norphlet Formation. The isopach exhibits a strong north-northwest-south-southeast orientation of parallel thicks and thins. These trends are believed to be the result of original eolian deposition of complex linear dunes in the Norphlet Sandstone. The major east-west structural grain of faults and anticlines overprints this preserved depositional trend.

  7. Reservoir sandstone bodies in lower Silurian Clinton sandstone interval, eastern Ohio

    SciTech Connect

    Coogan, A.H.

    1987-09-01

    The stratigraphic relationships of the sandstones, shales, limestones, dolomites, and related beds of the Lower Silurian Clinton sandstone interval in Ohio have been examined using several thousand well logs from Medina County to Coshocton County in eastern Ohio. This north-south band of counties lies semiparallel to the north-northeast-trending depositional edge of the Clinton lower deltaic and coastal plain. Continuous and discontinuous bar sandstones with patterns similar to barrier island deposits are found at the edge of the deltaic plain. The thicker sandstone reservoirs in these deposits have been prolific oil and gas pools. The discontinuous bar sands are more common, however, and where drilling is sparse or where only the cleaner sandstones are mapped, these bar sands appear as isolated, thick, porous sandstone bodies. Examples exist in Holmes and Wayne Counties, Ohio. Elongate, nearly straight, narrow sandstone bodies occur on the lower deltaic plain, and were deposited in channels that were fluvial or partly estuarine. The channel sandstones are less than 1000 ft wide, extend for distances up to 10 mi and can be seen in Coshocton, Summit, and Medina Counties. The reservoirs in these sandstones are prolific oil and gas producers, but they are not easy to locate. At the seaward end of the elongate channel, sandstones are thick, localized sand bodies that fit in the sedimentological picture as river mouth bars. An example from Medina County illustrates this reservoir geometry at the site of excellent oil production from the Clinton interval.

  8. Exploration models for submarine slope sandstones

    SciTech Connect

    Slatt, R.M.

    1986-09-01

    Recent published studies have demonstrated a far greater potential than previously recognized for submarine slope sandstones to contain significant oil and gas reserves in the Gulf Coast and elsewhere. Comparison of modern slopes with outcrop and subsurface analogs from several areas provided the framework for developing the following submarine slope sandstone exploration models: submarine canyon fill, slope gully/channel fill, slope spillover sand sheets, and intraslope basin fill. Submarine canyon fill is mainly shale, but sandstone beds that form stratigraphic traps may be present. Canyon shale fill juxtaposed against older sandstones can also form stratigraphic traps. Gully/channel fills are sandstones deposited on shallow-gradient slopes or ramps. The proximity of these sandstones to slope shales provides opportunities for stratigraphic traps to develop. Spillover sand sheets are resedimented from a shelf to a shallow-gradient slope and are associated with gully/channel fills. Intraslope basin fill is mainly shale, but elongate, sheetlike, or fan-shaped turbidite sandstones can provide stratigraphic traps. In all of these deposits, slope shales may be sufficiently enriched in organic carbon to be potential hydrocarbon source rocks; the potential for organic-rich shales to accumulate is highest in intraslope basin fill.

  9. Sandstone compaction: Basis for porosity predictive capabilities

    SciTech Connect

    Houseknecht, D.W.; Dincau, A.R.; Freeman, C.W. )

    1991-03-01

    Prediction of sandstone porosity must be based on understanding physical and chemical processes that are genetically linked to geologic history. Petrographic studies of sandstones of diverse geologic history indicate that reduction of intergranular volume (IGV) by compaction is the primary control of porosity in most cases. Moreover, these studies demonstrate that compaction can commonly be related to geologic history. Maximum depth of burial exerts a primary control on compaction in nondeformed and mildly deformed basins. For example, Miocene sandstones of Louisiana and Tertiary and Cretaceous sandstones of the Green River basin display progressive compaction to the depth limit of conventional core control. Compaction has reduced average IGV to less than 20% at 7.5 km (25,000 ft) depth in Miocene sandstones of Louisiana and to less than 10% at 5.3 km (17,500 ft) depth in Cretaceous sandstones in the Green River basin. Differences in absolute values of IGV in these basins reflect other geologic variables that have influenced compaction, including thermal maturity and age. In both basins, a progressive gradation from predominantly mechanical compaction-shallow to predominantly chemical compaction-deep is observed. Previous work in older basins indicates that chemical compaction remains an important agent of porosity modification in sandstones that undergo additional physical, chemical, and thermal stress. Compaction progressively reduces the intergranular volume of sandstones, thereby directly controlling intergranular porosity and influencing chemical diagenesis by modifying plumbing systems. Thus quantification of compaction in sandstones of diverse geologic history is fundamental to the development of porosity predictive capabilities.

  10. Survey of Navajo Community Studies, 1936-1974. Lake Powell Research Project Bulletin Number 6, March 1975.

    ERIC Educational Resources Information Center

    Henderson, Eric B.; Levy, Jerrold E.

    Extant Navajo community studies conducted since the 1930's were surveyed. Data for selected social, economic, and demographic variables as reported in these studies were compared. Each community study was placed in one of three geographic classifications: western Navajo, eastern Navajo, and off-reservation. Each on-reservation area was subdivided

  11. 25 CFR 161.713 - How will BIA determine the amount of damages to Navajo Partitioned Lands?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How will BIA determine the amount of damages to Navajo... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Trespass Penalties, Damages, and Costs 161.713 How will BIA determine the amount of damages to Navajo Partitioned Lands? (a) BIA will determine...

  12. Rural Navajo Students in Kayenta Unified School District's Special Education Programs: The Effects of Home Location and Language.

    ERIC Educational Resources Information Center

    Heimbecker, Connie; Bradley-Wilkinson, Evangeline; Nelson, Bernita; Smith, Jody; Whitehair, Marsha; Begay, Mary H.; Bradley, Brian; Gamble, Armanda; McCarty, Nellie; Medina, Catherine; Nelson, Jacob; Pettigrew, Bobbie; Sealander, Karen; Snyder, Maria; White, Sherri; Redsteer, Denise; Prater, Greg

    In Kayenta Unified School District (KUSD) on the Navajo Reservation, 92 percent of students come from homes where Navajo is the primary language, but many students entering school are not fluent in either English or Navajo. A survey of 23 educators examined the effects of language and culture on the likelihood that a student would be placed in

  13. Up against Giants: The National Indian Youth Council, the Navajo Nation, and Coal Gasification, 1974-77

    ERIC Educational Resources Information Center

    Shreve, Bradley Glenn

    2006-01-01

    In the spring of 1977, members of the National Indian Youth Council (NIYC), along with the Coalition for Navajo Liberation, barraged the Secretary of the Interior and the chairman of the Navajo Nation with petitions calling for a halt to the proposed construction of several coal gasification plants on the Navajo Reservation in northwestern New…

  14. Up against Giants: The National Indian Youth Council, the Navajo Nation, and Coal Gasification, 1974-77

    ERIC Educational Resources Information Center

    Shreve, Bradley Glenn

    2006-01-01

    In the spring of 1977, members of the National Indian Youth Council (NIYC), along with the Coalition for Navajo Liberation, barraged the Secretary of the Interior and the chairman of the Navajo Nation with petitions calling for a halt to the proposed construction of several coal gasification plants on the Navajo Reservation in northwestern New

  15. 25 CFR 161.102 - What notifications are required that tribal laws apply to grazing permits on the Navajo...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws... tribal law or tribal policy that relates to this part. The Navajo Nation must notify BIA of the content... Navajo Nation law on their grazing permits. BIA will: (1) Provide individual written notice; or (2)...

  16. 25 CFR 161.102 - What notifications are required that tribal laws apply to grazing permits on the Navajo...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws... tribal law or tribal policy that relates to this part. The Navajo Nation must notify BIA of the content... Navajo Nation law on their grazing permits. BIA will: (1) Provide individual written notice; or (2)...

  17. 25 CFR 161.102 - What notifications are required that tribal laws apply to grazing permits on the Navajo...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws... tribal law or tribal policy that relates to this part. The Navajo Nation must notify BIA of the content... Navajo Nation law on their grazing permits. BIA will: (1) Provide individual written notice; or (2)...

  18. 25 CFR 161.102 - What notifications are required that tribal laws apply to grazing permits on the Navajo...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws... tribal law or tribal policy that relates to this part. The Navajo Nation must notify BIA of the content... Navajo Nation law on their grazing permits. BIA will: (1) Provide individual written notice; or (2)...

  19. 25 CFR 161.102 - What notifications are required that tribal laws apply to grazing permits on the Navajo...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws... tribal law or tribal policy that relates to this part. The Navajo Nation must notify BIA of the content... Navajo Nation law on their grazing permits. BIA will: (1) Provide individual written notice; or (2)...

  20. Total petroleum systems of the Pelagian Province, Tunisia, Libya, Italy, and Malta; the Bou Dabbous, Tertiary and Jurassic-Cretaceous composite

    USGS Publications Warehouse

    Klett, T.R.

    2001-01-01

    Undiscovered conventional oil and gas resources were assessed within total petroleum systems of the Pelagian Province (2048) as part of the U.S. Geological Survey World Petroleum Assessment 2000. The Pelagian Province is located mainly in eastern Tunisia and northwestern Libya. Small portions of the province extend into Malta and offshore Italy. Although several petroleum systems may exist, only two ?composite? total petroleum systems were identified. Each total petroleum system comprises a single assessment unit. These total petroleum systems are called the Bou Dabbous?Tertiary and Jurassic-Cretaceous Composite, named after the source-rock intervals and reservoir-rock ages. The main source rocks include mudstone of the Eocene Bou Dabbous Formation; Cretaceous Bahloul, Lower Fahdene, and M?Cherga Formations; and Jurassic Nara Formation. Known reservoirs are in carbonate rocks and sandstone intervals throughout the Upper Jurassic, Cretaceous, and Tertiary sections. Traps for known accumulations include fault blocks, low-amplitude anticlines, high-amplitude anticlines associated with reverse faults, wrench fault structures, and stratigraphic traps. The estimated means of the undiscovered conventional petroleum volumes in total petroleum systems of the Pelagian Province are as follows: [MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids] Total Petroleum System MMBO BCFG MMBNGL Bou Dabbous?Tertiary 667 2,746 64 Jurassic-Cretaceous Composite 403 2,280 27

  1. Clastic Pipes: Proxies of High Water Tables and Strong Ground Motion, Jurassic Carmel Formation, Southern Utah

    NASA Astrophysics Data System (ADS)

    Wheatley, David; Chan, Marjorie

    2015-04-01

    Multiple soft sediment deformation features from bed-scale to basin-scale are well preserved within the Jurassic Carmel Formation of Southern Utah. Field mapping reveals thousands of small-scale clastic injectite pipes (10 cm to 10 m diameter, up to 20 m tall) in extremely high densities (up to 500+ pipes per 0.075 square kilometers). The pipes weather out in positive relief from the surrounding host strata of massive sandstone (sabkha) and crossbedded sands with minor conglomerate and shale (fluvial) deposits. The host rock shows both brittle and ductile deformation. Reverse, normal, and antithetical faulting is common with increased frequency, including ring faults, surrounding the pipes. The pipes formed from liquefaction and subsequent fluidization induced by strong ground motion. Down-dropped, graben blocks and ring faults surrounding pipes indicate initial sediment volume increase during pipe emplacement followed by sediment volume decrease during dewatering. Complex crosscutting relationships indicate several injection events where some pipe events reached the surface as sand blows. Multiple ash layers provide excellent stratigraphic and temporal constraints for the pipe system with the host strata deposited between 166 and 164 Ma. Common volcanic fragments and rounded volcanic cobbles occur within sandstone and conglomerate beds, and pipes. Isolated volcanic clasts in massive sandstone indicate explosive volcanic events that could have been the exogenic trigger for earthquakes. The distribution of pipes are roughly parallel to the Middle Jurassic paleoshoreline located in marginal environments between the shallow epicontinental Sundance Sea and continental dryland. At the vertical stratigraphic facies change from dominantly fluvial sediments to dominantly massive sabkha sediments, there is a 1-2 m-thick floodplain mudstone that was a likely seal for underlying, overpressurized sediments. The combination of loose porous sediment at a critical depth of water saturation made the system extremely susceptible to liquefaction. Fluid inclusions of carbonate nodules present on the pipe margins indicate salinity, temperature, and character of possible early diagenetic fluids before significant burial. These inclusions can reveal information about brines from point sources or fed via groundwater. Overall, the combination of clastic pipes and their related soft deformation structures in the host rock provide proxies for the existence of high water table conditions within arid climate regimes and transitional paleoenvironments previously assumed to be devoid of significant amounts of water. The pipe distribution and evidence of multiple injectite events paralleling an ancient paleoshoreline provides basin-scale insights on repeated paleoseismicity and volcanism along the convergent boundary of the Cordilleran.

  2. Implications of an eolian sandstone unit of Basal Morrison Formation, central Wyoming

    SciTech Connect

    Weed, D.D.; Vondra, C.F.

    1987-05-01

    A laterally discontinuous fine-grained quartzarenite occurs at the base of the Upper Jurassic Morrison Formation in the southern Big Horn and Powder River basins and in the Wind River basin. The sandstone unit is interpreted to be an eolianite. Evidence for this includes high-angle (20-35/sup 0/), medium to large-scale planar cross-beds that are tangential at the base, inversely graded foresets, and discrete dune formation in some areas. Cross-bed set thickness ranges from 1 to 10 m. Soft sediment deformation in the form of small-scale contortions is common in dune cross-stratification. The eolianite is 10-55 m thick and conformably overlies the transitional marine Windy Hill Sandstone Member of the upper Sundance Formation. Paleocurrent data suggest a northward transportation direction. On exposed planar surfaces of foresets, nonmarine ichnofauna are present including small vertebrate trackways. This eolian facies represents a unique setting within the predominantly fluvial and lacustrine mudstones of the Morrison Formation and may be indicative of localized small-scale uplifts associated with Sevier compressional activity to the west. Based upon lithology and stratigraphic position of the eolianite, the geological history of central Wyoming during late Oxfordian to early Kimmeridgian time can be reconstructed as follows: as the Sundance sea withdrew from central Wyoming, a blanket of lagoonal, lacustrine, and flood-plain mudstones and small channel sandstones were deposited in an area of very low topographical relief. In response to compression to the west, subtle uplifts occurred locally in south-central and southeastern Wyoming, resulting in erosion of the upper Sundance marine sandstones. Patches of windblown eroded fine sands were subsequently deposited within the nonmarine mudstones in nearby eolian environments to the north.

  3. Dine Baa Hane Bi Naaltsoos: Collected Papers from the Seventh through Tenth Navajo Studies Conferences.

    ERIC Educational Resources Information Center

    Piper, June-el, Ed.

    This document contains 29 papers presented at the 7th-10th Navajo Studies Conferences, 1994-97. The papers are arranged in five sections: "Aesthetics: Rugs, Baskets, and Rock Art"; "Doing Anthropology"; "Health"; "Economics"; and "Contact between Cultures." The papers are: "The First Navajo Studies Conference: Reflections by the Cofounders"…

  4. Racing against Time: A Report on the Leupp Navajo Immersion Project.

    ERIC Educational Resources Information Center

    Fillerup, Michael

    This paper describes a federally funded language preservation program at Leupp Public School, part of Flagstaff (Arizona) Unified School District but located on the Navajo Reservation. Funded in 1997 for 5 years, this schoolwide project is designed to help elementary students become proficient speakers, readers, and writers of Navajo while…

  5. The Circulation and Silence of Weaving Knowledge in Contemporary Navajo Life

    ERIC Educational Resources Information Center

    Yohe, Jill Ahlberg

    2012-01-01

    This article draws upon ethnographic fieldwork within a Navajo community to illustrate how weaving knowledge and practices shape contemporary notions of community identity and belonging. The ongoing exchange of Navajo weaving taboos and the careful management of weaving teachings offers community members various opportunities to share and keep…

  6. 40 CFR 147.3400 - Navajo Indian lands-Class II wells.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained or inspected at the Navajo Nation... General of the Navajo Nation Pursuant to 40 CFR 145.24”, August 27, 2001. (2) “Statement of the...

  7. Dine Baa Hane Bi Naaltsoos: Collected Papers from the Seventh through Tenth Navajo Studies Conferences.

    ERIC Educational Resources Information Center

    Piper, June-el, Ed.

    This document contains 29 papers presented at the 7th-10th Navajo Studies Conferences, 1994-97. The papers are arranged in five sections: "Aesthetics: Rugs, Baskets, and Rock Art"; "Doing Anthropology"; "Health"; "Economics"; and "Contact between Cultures." The papers are: "The First Navajo Studies Conference: Reflections by the Cofounders"

  8. Emerging Role of the Teacher Aide in Navajo Education. A Guide Book.

    ERIC Educational Resources Information Center

    Pratt, Wayne T., Ed.; Ramey, Joseph H., Ed.

    Based on the experiences of 52 Navajo teacher aides in a 10 week training course (1974), this teacher aide guide book for all grade levels is primarily descriptive, though "helpful hints" are provided for teacher aides in Bureau of Indian Affairs schools for Navajo children. Emphasizing the importance of the teacher aide's role in the "team

  9. "Please Read Loose": Intimate Grammars and Unexpected Languages in Contemporary Navajo Literature

    ERIC Educational Resources Information Center

    Webster, Anthony K.

    2011-01-01

    This paper uses Philip Deloria's "Indians in Unexpected Places" as a lens by which to understand the expectations and reviews of Navajo author Blackhorse Mitchell's "Miracle Hill." Written in Navajo English, the book, from an introduction by T. D. Allen to a number of reviews of the book in the popular press, consistently misrecognized the

  10. An Initial Exploration of the Navajo Nation's Language and Culture Initiative.

    ERIC Educational Resources Information Center

    Bachelder, Ann; Markel, Sherry

    This paper presents some preliminary findings from an opinion survey on the nature and depth of language and cultural studies to be included in school curricula as required by the Navajo Tribe's Language and Culture Mandate (1984). A 10-question survey was sent to 20 elementary and secondary schools in the Navajo Nation in New Mexico and Arizona.

  11. Peoples, Resources, and Lifestyles: The Hopi-Navajo Land Partition Act of 1974.

    ERIC Educational Resources Information Center

    Goodman, James M.

    The Hopi and Navajo tribes have been engaged in a long and complex land dispute within the 1882 Executive Order Area (Joint Use Area) of Arizona, an area recently redefined via the Partition Act of 1974 which calls for the relocation of 5 to 10,000 Navajos. This rearrangement of political domain threatens to influence the future management and…

  12. Bringing Navajo Storytelling Practices into Schools: The Importance of Maintaining Cultural Integrity

    ERIC Educational Resources Information Center

    Eder, Donna J.

    2007-01-01

    This article examines storytelling practices among Navajos as one example of a non-Western approach to education. The article discusses two stories--one regarding the perspectives of Navajo storytellers concerning the importance of the context of storytelling practices and the other about the research process that led to these perspectives. Eight

  13. Psychosocial and health impacts of uranium mining and milling on Navajo lands.

    PubMed

    Dawson, Susan E; Madsen, Gary E

    2011-11-01

    The uranium industry in the American Southwest has had profoundly negative impacts on American Indian communities. Navajo workers experienced significant health problems, including lung cancer and nonmalignant respiratory diseases, and psychosocial problems, such as depression and anxiety. There were four uranium processing mills and approximately 1,200 uranium mines on the Navajo Nation's over 27,000 square miles. In this paper, a chronology is presented of how uranium mining and milling impacted the lives of Navajo workers and their families. Local community leaders organized meetings across the reservation to inform workers and their families about the relationship between worker exposures and possible health problems. A reservation-wide effort resulted in activists working with political leaders and attorneys to write radiation compensation legislation, which was passed in 1990 as the Radiation Exposure Compensation Act (RECA) and included underground uranium miners, atomic downwinders, and nuclear test-site workers. Later efforts resulted in the inclusion of surface miners, ore truck haulers, and millworkers in the RECA Amendments of 2000. On the Navajo Nation, the Office of Navajo Uranium Workers was created to assist workers and their families to apply for RECA funds. Present issues concerning the Navajo and other uranium-impacted groups include those who worked in mining and milling after 1971 and are excluded from RECA. Perceptions about uranium health impacts have contributed recently to the Navajo people rejecting a resumption of uranium mining and milling on Navajo lands. PMID:21979550

  14. Reaching American Indian Special/Elementary Educators through a Partnership with a Navajo Nation School District.

    ERIC Educational Resources Information Center

    Heimbecker, Connie; Medina, Catherine; Peterson, Patricia; Redsteer, Denise; Prater, Greg

    2002-01-01

    This article describes the Reaching American Indian Special/Elementary Educators (RAISE) program, a community-based native teacher education program located on the Navajo reservation in Kayenta, Arizona. The preservice teacher preparation partnership program is designed for uncertified Navajo special and elementary education preservice students

  15. Teenage Mothering on the Navajo Reservation: An Examination of Intergenerational Perceptions and Beliefs.

    ERIC Educational Resources Information Center

    Dalla, Rochelle L.; Gamble, Wendy C.

    2001-01-01

    A study examined attitudes towards teenage motherhood among 25 Navajo reservation residents, including 8 teenage mothers, their mothers, and 4 teenage fathers. Findings indicate that teenage parenting was discouraged despite the matrilineal nature of Navajo society, men were frequently absent from family life, single maternity was preferable to

  16. Working with Navajo Special Education Students on the Reservation: Cultural Implications.

    ERIC Educational Resources Information Center

    Watt, Carolyn; Sorgnit, Heather; Medina, Catherine; Jennings, Marianne; Heimbecker, Connie; Gonnie, Pat; Dugi, Audrelia; Bowsley, Virginia; Prater, Greg

    A study in the Kayenta Unified School District (Arizona) on the Navajo Nation--the largest reservation in the United States--examined cultural and language barriers in teaching Navajo special education students. Questionnaires were returned from 26 teachers at all grade levels, and interviews were conducted with 5 teachers and the district

  17. A Dine (Navajo) Perspective on Self-Determination: An Exposition of an Egalitarian Place

    ERIC Educational Resources Information Center

    Manuelito, Kathryn D.

    2006-01-01

    Worldview of any culture and society is explicated through epistemological principles that frame the way one sees the world. Dine (Navajo) worldview is explicated through epistemology that has been rejected and debased by the dominant society since contact centuries ago. However, enduring powerful Dine (Navajo) worldview persists in contemporary

  18. The Navajo Way: Arizona's Tale of Two CTE Programs

    ERIC Educational Resources Information Center

    Helfman, Alan

    2001-01-01

    Arizona has begun an organized effort at career planning designed to create graduates who know who they are, know where they are going and know how they are going to get there. The Navajos are well on their way to achieving these kinds of student outcomes. This article focuses on two Navajo schools: Ganado High School, a comprehensive high school

  19. 30 CFR 756.14 - Approval of amendments to the Navajo Nation's abandoned mine land plan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Approval of amendments to the Navajo Nation's... PROGRAMS 756.14 Approval of amendments to the Navajo Nation's abandoned mine land plan. (a) Revisions to... Water Subsequent to Certification II(O) (1)Exclusion of Noncoal Reclamation Sites II(P) (1), (2),...

  20. 30 CFR 756.14 - Approval of amendments to the Navajo Nation's abandoned mine land plan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Approval of amendments to the Navajo Nation's... PROGRAMS 756.14 Approval of amendments to the Navajo Nation's abandoned mine land plan. (a) Revisions to... Water Subsequent to Certification II(O) (1)Exclusion of Noncoal Reclamation Sites II(P) (1), (2),...

  1. 30 CFR 756.14 - Approval of amendments to the Navajo Nation's abandoned mine land plan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Approval of amendments to the Navajo Nation's... PROGRAMS 756.14 Approval of amendments to the Navajo Nation's abandoned mine land plan. (a) Revisions to... Water Subsequent to Certification II(O) (1)Exclusion of Noncoal Reclamation Sites II(P) (1), (2),...

  2. The Circulation and Silence of Weaving Knowledge in Contemporary Navajo Life

    ERIC Educational Resources Information Center

    Yohe, Jill Ahlberg

    2012-01-01

    This article draws upon ethnographic fieldwork within a Navajo community to illustrate how weaving knowledge and practices shape contemporary notions of community identity and belonging. The ongoing exchange of Navajo weaving taboos and the careful management of weaving teachings offers community members various opportunities to share and keep

  3. 40 CFR 147.3400 - Navajo Indian lands-Class II wells.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained or inspected at the Navajo Nation... General of the Navajo Nation Pursuant to 40 CFR 145.24”, August 27, 2001. (2) “Statement of the Attorney.... 147.3400 Section 147.3400 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  4. 78 FR 36716 - Approval of Air Quality Implementation Plans; Navajo Nation; Regional Haze Requirements for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-19

    ... FR 8274). List of Subjects in 40 CFR Part 49 Environmental protection, Air pollution control, Indians... X ) from the Navajo Generating Station (NGS), located on the Navajo Nation. EPA provided a three... on the proposed BART determination for NGS. DATES: EPA will announce dates and locations for...

  5. Navajo Language Maintenance III: Accessibility of School and Town as a Factor in Language Shift.

    ERIC Educational Resources Information Center

    Spolsky, Bernard

    Two centers of diffusion of the English language are (1) schools on the Navajo Reservation and (2) off-Reservation towns; these diffusion centers were studied to examine factors involved in language shift, especially in terms of internal (on-Reservation) and external (off-Reservation) contacts with English. Teachers in schools with Navajo pupils

  6. No One Remembers a Winter Like This: A Year at the Navajo Agency, 1882-1883.

    ERIC Educational Resources Information Center

    Lockard, Louise

    This paper documents a single year in the history of Navajo education from the perspective of the Navajo Agent Dennis Matthew Riordan. It draws on Riordan's correspondence, 1882-83, with the Secretary of the Interior, with Captain Richard Henry Pratt at the Carlisle Indian Industrial School, and with his brother. In December 1882, Riordan arrived…

  7. 30 CFR 756.13 - Approval of the Navajo Nation's abandoned mine land plan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Approval of the Navajo Nation's abandoned mine land plan. 756.13 Section 756.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.13 Approval of the Navajo...

  8. Remote detection of fluid-related diagenetic mineralogical variations in the Wingate Sandstone at different spatial and spectral resolutions

    NASA Astrophysics Data System (ADS)

    Okyay, Unal; Khan, Shuhab D.

    2016-02-01

    Well-exposed eolian units of the Jurassic system on the Colorado Plateau including the Wingate Sandstone, show prominent color variations throughout southeastern Utah due to diagenetic changes that include precipitation and/or removal of iron oxide, clay, and carbonate cement. Spatially variable characteristic diagenetic changes suggest fluid-rock interactions through the sandstone. Distinctive spectral signatures of diagenetic minerals can be used to map diagenetic mineral variability and possibly fluid-flow pathways. The main objective of this work was to identify characteristic diagenetic minerals, and map their spatial variability from regional to outcrop scale in Wingate Sandstone exposures of Lisbon Valley, Utah. Laboratory reflectance spectroscopy analysis of the samples facilitated identification of diagnostic spectral characteristics of the common diagenetic minerals and their relative abundances between altered and unaltered Wingate Sandstone. Comparison of reflectance spectroscopy with satellite, airborne, and ground-based imaging spectroscopy data provided a method for mapping and evaluating spatial variations of diagenetic minerals. The Feature-oriented Principal Component Selection method was used on Advanced Spaceborne Thermal Emission and Reflection Radiometer data so as to map common mineral groups throughout the broader Wingate Sandstone exposure in the area. The Minimum Noise Fraction and Spectral Angle Mapper methods were applied on airborne HyMap and ground-based hyperspectral imaging data to identify and map mineralogical changes. The satellite and airborne data showed that out of 25.55 km2 total exposure of Wingate Sandstone in Lisbon Valley, unaltered sandstone cover 12.55 km2, and altered sandstone cover 8.90 km2 in the northwest flank and 5.09 km2 in the southern flank of the anticline. The ground-based hyperspectral data demonstrated the ability to identify and map mineral assemblages with two-dimensional lateral continuity on near-vertical rock faces. The results showed that 39.71% of the scanned outcrop is bleached and 20.60% is unbleached while 6.33% remain unclassified, and 33.36% is masked-out as vegetation. The bleached and unbleached areas are alternating throughout the vertical face of the outcrop. The relative hematite abundance observed in the unbleached areas are somewhat symmetrical. This indicates fairly similar reaction intensities along the upper and lower reaction fronts observed in the vertical section. The distribution geometry and relative abundances of diagenetic minerals not only suggest multiple paths of fluid-flow in Wingate Sandstone but also provides some insight about relative direction of past fluid-flow.

  9. Sedimentological setting of sandstone-type uranium deposits in coal measures on the southwest margin of the Turpan-Hami Basin, China

    NASA Astrophysics Data System (ADS)

    Wu, Liqun; Jiao, Yangquan; Roger, Mason; Yang, Shengke

    2009-09-01

    Sandstone-type uranium deposits usually exist in coal measures. This stratigraphy study found that the Jurassic coal measures (Shuixigou Group) at the southwest margin of the Turpan-Hami Basin consist of the Badaowan, Sangonghe and Xishanyao formations, which correspond to sequences A, B and C, respectively. Sequence C can be divided into the lowstand systems tract (LST), expanding lacustrine systems tract (EST) and highstand systems tract (HST). Uranium mineralization mainly develops in sequence C, in which LST and HST are the main mineralization strata while EST is the secondary mineralization stratum. High-resolution study of depositional systems tracts indicates that the fine sediments around the boundaries of parasequences can form the confining beds of uranium metallogenetic fluid systems. Within parasequences, the braided channel sandstones and part large-scale braided distributary channel sandstones have a close relationship with strong interlayer oxidation and uranium mineralization. Periodical development of parasequences conduces to the frequent growth of large skeletal sandstones and confining beds. That is the essential reason for the complexity of uranium mineralization in depositional systems tracts. The study also found that different depositional systems lead to obvious differences in the spatial distribution structures of skeletal sandstones and confining beds. LST and HST mainly comprise braided stream depositional systems, where uranium skeletal sandstones develop and are always located in the middle and lower parts of the parasequences, while confining beds are always located in the upper part of parasequences. While EST mainly comprises braided delta depositional systems, where uranium skeletal sandstones have a relatively small scale and are always located in the middle part of parasequences, confining beds are always located in the lower and upper parts of parasequences. Thus, the study of depositional systems tracts in sequence is only suitable for the primary exploration stage of sandstone-type uranium deposits, and parasequences are the best evaluation units in the advanced exploration stage.

  10. Suitability of Frigg, re, and Sognefjord Formation sandstones (North Sea) for storage of CO2

    NASA Astrophysics Data System (ADS)

    Saether, O. M.; Webb, J. C.; Wissing, B. W.; Be, R.

    2012-12-01

    The steady increase in concentration of CO2 in the atmosphere owing to the combustion of hydrocarbons is considered a major factor contributing to global warming. The storage of CO2 as subcritical gas in depleted oil and gas reservoirs and deep aquifers is considered a viable mitigation for reducing the impact of global temperature increase as a consequence of increased atmospheric CO2 (Hitcheon 1999, Bachu 2008). The volume of CO2 stored in the subsurface as supercritical liquid in any given sedimentary rock formation could be limited to <1% of the total pore space. Storage of larger volumes might lead to increased pressure and cause injection rates to undergo exponential decline (Ehlig-Economides and Economides 2010). Petrographic investigations of samples of sandstone from three quartz-rich sandstone formations in the Norwegian part of the North Sea, i.e. Tertiary Frigg Formation, Lower Jurassic re Formation, and Upper Jurassic Sognefjord Formation, reveal that all three sandstone formations exhibit features that favor suitability for CO2 storage. Favorable features include: 1) Abundant effective porosity 2) Stable mineralogy (i.e. abundant quartz) 3) Lack of chemically unstable detrital minerals (i.e. potassium and plagioclase feldspar, carbonates, volcanic rock fragments) 4) Lack of acid-soluble cements (e.g. iron-chlorite clay, siderite, calcite, or dolomite) 5) Lack of fresh-water sensitive (expansive) clay mineral cements (e.g. montmorillonite and mixed-layer illite-smectite (ML-IS). Intergranular porosity for each of the formations is estimated to be 28-31% of total rock volume for the Frigg Formation, 19-34% for the re Formation, and 16-29% for the Sognefjord Formation. Intergranular porosity of sandstones in each of the three formations is very well connected. Pore-throat radii of intergranular pores are interpreted to be significantly larger than 0.5 ?m. Pore throats are not occluded by clay mineral cements, resulting in excellent estimated permeability. Microporosity within pore-filling kaolinite cement for the Frigg Formation is 2-5% of total rock volume, for the re Formation 3-6%, and for the Sognefjord Formation 3-10%. Irreducible water saturation caused by high specific surface area of kaolinite cements and pore throat radii within kaolinite cement of <0.5 ?m is interpreted to be minor, with the exception of one sample from the Sognefjord Formation.

  11. Jurassic platform development, northwestern Gulf of Mexico

    SciTech Connect

    Moore, C.H. Jr.

    1987-05-01

    Triassic and Early Jurassic rifting set the stage for the subsequent development of carbonate platforms in the Late Jurassic. These platforms formed along the interior margins of salt basins separated from the main ancestral Gulf of Mexico by a series of positive features. A major sea level rise, after deposition of the Louann Salt (late Callovian), drowned the interior salt basins around the margins of the Gulf of Mexico, leading to an anoxic event. Organic-rich sediments of the lower Smackover were deposited as a basin-fill sequence, forming one of the major hydrocarbon source rocks of the region. As sea level rise slowed in the late Oxfordian, carbonate production began to catch up with sea level rise along the basin margins, leading to the initial development of a rimmed carbonate platform. The platform margin was marked by high-energy ooid grainstones, while crustacean pellet muds were deposited in the platform interior. A high-energy ooid-dominated platform (upper Smackover) developed in the late Oxfordian when sea level reached a standstill. During the subsequent Kimmeridgian sea level rise, a second rimmed carbonate platform, the Haynesville, was developed. During the initial rise, grainstones were deposited on the platform margin, while the interior was dominated by evaporites (Buckner) and siliciclastics. As sea level slowed and reached a standstill, the platform margin facies extended shoreward (Gilmer) and a high-energy platform, analogous to the upper Smackover, was formed. The Smackover and Haynesville platforms of the northwestern gulf show a parallel evolution in response to cyclic changes in Upper Jurassic sea level.

  12. Paleoenvironments and hydrocarbon potential of Upper Jurassic Norphlet Formation of southwestern Alabama and adjacent coastal water area

    SciTech Connect

    Mancini, E.A.; Mink, R.M.; Bearden, B.L.

    1984-09-01

    Upper Jurassic Norphlet sediments in southwestern Alabama and the adjacent coastal water area accumulated under arid climatic conditions. The Appalachian Mountains of the eastern United States extended into southwestern Alabama, providing a barrier for air and water circulation during Norphlet deposition. Norphlet paleogeography was dominated by a broad desert plain rimmed to the north and east by the Appalachians and to the south by a developing shallow sea. Initiation of Norphlet sedimentation was a result of erosion of the southern Appalachians. Norphlet conglomerates were deposited in coalescing alluvial fans in proximity to an Appalachian source. The conglomeratic sandstones grade downdip into red-bed lithofacies that accumulated in distal portions of alluvial fan and wadi systems. Quartzose sandstones (Denkman Member) were deposited as dune and interdune sediments on a broad desert plain. The source of the sand was the updip and adjacent alluvial fan, plain, and wadi deposits. A marine transgression was initiated late in Denkman deposition, resulting in the reworking of previously deposited Norphlet sediments. Norphlet hydrocarbon potential in southwestern and offshore Alabama is excellent with four oil and gas fields already established. Petroleum traps discovered to date are primarily structural traps involving salt anticlines, faulted salt anticlines, and extensional fault traps associated with salt movement. Reservoir rocks consist of quartzose sandstones, which are principally eolian in origin. Smackover algal carbonate mudstones were probably the source for the Norphlet hydrocarbons.

  13. Materials Prepared All or in Part as Result of Office of Education Small Research Grant OEG-9-9-120076-0050(057) [To Navajo Community College].

    ERIC Educational Resources Information Center

    Gorman, Howard; And Others

    Through funds provided by the U.S. Office of Education and the Navajo Community College, a major accomplishment was realized in the development of a Navajo Studies Curriculum that reflects the thinking of the Navajos themselves. The most successful aspect of the project was the identification on the part of the Navajos of what they wanted included

  14. The Law of the People (Dine Bibee Haz'Aannii): A Bicultural Approach to Legal Education for Navajo Students, Volume 2.

    ERIC Educational Resources Information Center

    Vicenti, Dan; And Others

    Volume 2 of a 4-volume bilingual bicultural law-related curriculum deals with the evolution of a Navajo legal system. Navajo "law" was referred to by Navajos as "religion", thus Anglos viewed the Navajo as having no "law." Because of the complexity of this topic, it is suggested that the first sections covering this view be read and digested by

  15. The Navajo Atlas: Environments, Resources, People, and History of the Dine Bikeyah. The Civilization of the American Indian Series, Volume 157.

    ERIC Educational Resources Information Center

    Goodman, James M.

    The 48 maps and descriptive narratives in this atlas of the Navajo Reservation are divided into six sections. Part I, Navajo Country, displays Navajo land in relationship to the United States and the region, and becomes more detailed to place locations within the Dine Bikeyah, or Navajo Land, including administrative and political subdivisions of

  16. Cardiovascular disease in Navajo Indians with type 2 diabetes.

    PubMed Central

    Hoy, W; Light, A; Megill, D

    1995-01-01

    Rates of both type 2 diabetes and cardiovascular disease have risen sharply in recent years among Navajo Indians, the largest reservation-based American Indian tribe, but the association between the two conditions is not entirely clear. Rates of cardiovascular disease and some possible associations in several hundred diabetic and non-diabetic Navajos were estimated. Nearly one-third (30.9 percent) of those with diabetes had formal diagnoses of cardiovascular disease--25.3 percent had heart disease, 4.4 percent had cerebrovascular disease, and 4.1 percent had peripheral vascular disease. (The percentages exceed the total because some people had more than one diagnosis. Age-adjusted rates were 5.2 times those of nondiabetics for heart disease, 10.2 times for cerebrovascular disease, and 6.8 times for peripheral vascular disease. Accentuation of risk was most marked in young diabetics and in female diabetics. Hypertensive diabetics had a twofold increase in heart disease and more than a fivefold increase in cerebral and peripheral vascular disease over nonhypertensive diabetics. Age, blood pressure, cholesterol levels, and albumenuria were independent risk factors for cardiovascular disease. Triglyceride levels or body weight were not. Male sex and diabetes duration were independent risk factors for cerebral and peripheral vascular disease but not for heart disease. In view of the impressive segregation of cardiovascular disease in the diabetic Navajo population, the prevention of diabetes through population-based health promotion seems basic to its containment. Over the short term, vigorous treatment of hypertension in subjects who are already diabetic is mandatory. PMID:7838949

  17. Irrigation management with remote sensing. [Navajo Indian Irrigation Project

    NASA Technical Reports Server (NTRS)

    Harlan, C.; Heilman, J. L.; Moore, D.; Myers, V. (principal investigators)

    1982-01-01

    Two visible/near IR hand held radiometers and a hand held thermoradiometer were used along with soil moisture and lysimetric measurements in a study of soil moisture distribution in afalfa fields on the Navajo Indian Irrigation Project near farmington, New Mexico. Radiances from irrigated plots were measured and converted to reflectances. Surface soil water contents (o cm to 4 cm) were determined gravimetrically on samples collected at the same time as the spectral measurements. The relationship between the spectral measurements and the crop coefficient were evaluated to demonstrate potential for using spectral measurement to estimate crop coefficient.

  18. Jurassic climate mode governed by ocean gateway

    NASA Astrophysics Data System (ADS)

    Korte, Christoph; Hesselbo, Stephen P.; Ullmann, Clemens V.; Dietl, Gerd; Ruhl, Micha; Schweigert, Günter; Thibault, Nicolas

    2015-12-01

    The Jurassic (~201-145 Myr ago) was long considered a warm `greenhouse' period; more recently cool, even `icehouse' episodes have been postulated. However, the mechanisms governing transition between so-called Warm Modes and Cool Modes are poorly known. Here we present a new large high-quality oxygen-isotope dataset from an interval that includes previously suggested mode transitions. Our results show an especially abrupt earliest Middle Jurassic (~174 Ma) mid-latitude cooling of seawater by as much as 10 °C in the north-south Laurasian Seaway, a marine passage that connected the equatorial Tethys Ocean to the Boreal Sea. Coincidence in timing with large-scale regional lithospheric updoming of the North Sea region is striking, and we hypothesize that northward oceanic heat transport was impeded by uplift, triggering Cool Mode conditions more widely. This extreme climate-mode transition provides a counter-example to other Mesozoic transitions linked to quantitative change in atmospheric greenhouse gas content.

  19. Jurassic climate mode governed by ocean gateway

    PubMed Central

    Korte, Christoph; Hesselbo, Stephen P.; Ullmann, Clemens V.; Dietl, Gerd; Ruhl, Micha; Schweigert, Günter; Thibault, Nicolas

    2015-01-01

    The Jurassic (∼201–145 Myr ago) was long considered a warm ‘greenhouse' period; more recently cool, even ‘icehouse' episodes have been postulated. However, the mechanisms governing transition between so-called Warm Modes and Cool Modes are poorly known. Here we present a new large high-quality oxygen-isotope dataset from an interval that includes previously suggested mode transitions. Our results show an especially abrupt earliest Middle Jurassic (∼174 Ma) mid-latitude cooling of seawater by as much as 10 °C in the north–south Laurasian Seaway, a marine passage that connected the equatorial Tethys Ocean to the Boreal Sea. Coincidence in timing with large-scale regional lithospheric updoming of the North Sea region is striking, and we hypothesize that northward oceanic heat transport was impeded by uplift, triggering Cool Mode conditions more widely. This extreme climate-mode transition provides a counter-example to other Mesozoic transitions linked to quantitative change in atmospheric greenhouse gas content. PMID:26658694

  20. Jurassic climate mode governed by ocean gateway.

    PubMed

    Korte, Christoph; Hesselbo, Stephen P; Ullmann, Clemens V; Dietl, Gerd; Ruhl, Micha; Schweigert, Günter; Thibault, Nicolas

    2015-01-01

    The Jurassic (∼201-145 Myr ago) was long considered a warm 'greenhouse' period; more recently cool, even 'icehouse' episodes have been postulated. However, the mechanisms governing transition between so-called Warm Modes and Cool Modes are poorly known. Here we present a new large high-quality oxygen-isotope dataset from an interval that includes previously suggested mode transitions. Our results show an especially abrupt earliest Middle Jurassic (∼174 Ma) mid-latitude cooling of seawater by as much as 10 °C in the north-south Laurasian Seaway, a marine passage that connected the equatorial Tethys Ocean to the Boreal Sea. Coincidence in timing with large-scale regional lithospheric updoming of the North Sea region is striking, and we hypothesize that northward oceanic heat transport was impeded by uplift, triggering Cool Mode conditions more widely. This extreme climate-mode transition provides a counter-example to other Mesozoic transitions linked to quantitative change in atmospheric greenhouse gas content. PMID:26658694

  1. "Sydney sandstone": Heritage Stone from Australia

    NASA Astrophysics Data System (ADS)

    Cooper, Barry; Kramar, Sabina

    2014-05-01

    Sydney is Australia's oldest city being founded in 1788. The city was fortunate to be established on an extensive and a relatively undeformed layer of lithified quartz sandstone of Triassic age that has proved to be an ideal building stone. The stone has been long identified by geologists as the Hawkesbury Sandstone. On the other hand the term "Sydney sandstone" has also been widely used over a long period, even to the extent of being utilised as the title of published books, so its formal designation as a heritage stone will immediately formalise this term. The oldest international usage is believed to be its use in the construction of the Stone Store at Kerikeri, New Zealand (1832-1836). In the late 19th century, public buildings such as hospitals, court houses as well as the prominent Sydney Town Hall, Sydney General Post Office, Art Gallery of New South Wales, State Library of New South Wales as well as numerous schools, churches, office building buildings, University, hotels, houses, retaining walls were all constructed using Sydney sandstone. Innumerable sculptures utilising the gold-coloured stone also embellished the city ranging from decorative friezes and capitals on building to significant monuments. Also in the late 19th and early 20th century, Sydney sandstone was used for major construction in most other major Australian cities especially Melbourne, Adelaide and Brisbane to the extent that complaints were expressed that suitable local stone materials were being neglected. Quarrying of Sydney sandstone continues today. In 2000 it was recorded noted that there were 33 significant operating Sydney sandstone quarries including aggregate and dimension stone operations. In addition sandstone continues to be sourced today from construction sites across the city area. Today major dimension stone producers (eg Gosford Quarries) sell Sydney sandstone not only into the Sydney market but also on national and international markets as cladding and paving products as well as block. Recent international projects by Gosford Quarries include Mishima Golf Club in Japan, Al Awadi Tower in Kuwait, New World Resort in China and a Hard Rock Café in Florida, USA. Arguably Sydney sandstone is Australia's most prominent potential Global Heritage Stone Resource and details are readily available in existing publications to make the nomination.

  2. Lithological and Petrographic Analyses of Carbonates and Sandstones From the Southern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Garcia-Avendao, A.; Urrutia-Fucugauchi, J.

    2012-04-01

    We present results of sedimentological and petrological studies of drill cores from the Bay of Campeche in the southern Gulf of Mexico. Based on reports on drill cores obtained from oil exploratory wells in the Cantarell Complex located 80 kilometres offshore in the Bay of Campeche and studies related to regional geology composite simplified stratigraphic columns for offshore Campeche region have been constructed up to depths of approximately 5000 m. The stratigraphic column is formed by a thick sediment sequence of Middle Jurassic age (evaporites, Callovian), Late Jurassic (terrigenous, calcareous clays and calcareous layers), Lower Cretaceous (carbonates), Upper Cretaceous-Paleogene (calcareous breccias), Paleogene-Neogene (terrigenous-carbonates intercalations) and Quaternary (terrigenous). The core samples studied come from wells in the Sihil and Akal fields in Cantarell. Analysis of reports on lithological descriptions indicates that these wells sample dolomitized sedimentary breccias from the Upper Cretaceous-Paleocene and fine-grained sandstones from the Late Jurassic Tithonian, respectively. Based on results of petrographic studies, the texture, cementing material and porosity of the units have been documented. The thin sections for carbonates were classified based on their texture according to Dunham (1962) for carbonate rocks, classified according to their components using the ternary diagrams of Folk (1974). Percentages refer to the data presented in tables, which were obtained by point-counting technique (with a total 250). Photomicrographs of scanning electron microscope (SEM) provide magnification for easy documentation of crystalline arrangements and description of micro-porous for different types of carbonates such as dolomite, in addition to the morphology of authigenic clays. Results of these studies and previous works in the area permit characterization of diagenetic processes of the carbonate sediments in the Campeche Bay, and provide information related to oil maturation, storage and potential flow in the Cantarell reservoirs.

  3. Navajo Coal Combustion and Respiratory Health Near Shiprock, New Mexico

    PubMed Central

    Bunnell, Joseph E.; Garcia, Linda V.; Furst, Jill M.; Lerch, Harry; Olea, Ricardo A.; Suitt, Stephen E.; Kolker, Allan

    2010-01-01

    Indoor air pollution has been identified as a major risk factor for acute and chronic respiratory diseases throughout the world. In the sovereign Navajo Nation, an American Indian reservation located in the Four Corners area of the USA, people burn coal in their homes for heat. To explore whether/how indoor coal combustion might contribute to poor respiratory health of residents, this study examined respiratory health data, identified household risk factors such as fuel and stove type and use, analyzed samples of locally used coal, and measured and characterized fine particulate airborne matter inside selected homes. In twenty-five percent of homes surveyed coal was burned in stoves not designed for that fuel, and indoor air quality was frequently found to be of a level to raise concerns. The average winter 24-hour PM2.5 concentration in 20 homes was 36.0 μg/m3. This is the first time that PM2.5 has been quantified and characterized inside Navajo reservation residents' homes. PMID:20671946

  4. Navajo Coal Combustion and Respiratory Health Near Shiprock, New Mexico

    DOE PAGESBeta

    Bunnell, Joseph E.; Garcia, Linda V.; Furst, Jill M.; Lerch, Harry; Olea, Ricardo A.; Suitt, Stephen E.; Kolker, Allan

    2010-01-01

    Indoormore » air pollution has been identified as a major risk factor for acute and chronic respiratory diseases throughout the world. In the sovereign Navajo Nation, an American Indian reservation located in the Four Corners area of the USA, people burn coal in their homes for heat. To explore whether/how indoor coal combustion might contribute to poor respiratory health of residents, this study examined respiratory health data, identified household risk factors such as fuel and stove type and use, analyzed samples of locally used coal, and measured and characterized fine particulate airborne matter inside selected homes. In twenty-five percent of homes surveyed coal was burned in stoves not designed for that fuel, and indoor air quality was frequently found to be of a level to raise concerns. The average winter 24-hour PM 2.5 concentration in 20 homes was 36.0  μ g/ m 3 . This is the first time that PM 2.5 has been quantified and characterized inside Navajo reservation residents' homes.« less

  5. Vegetation surveys: A 12-year history at Navajo Mine

    SciTech Connect

    Wood, M.K.; Buchanan, B.A.; Denetclaw, P.

    1995-09-01

    Since 1983, vegetal surveys on referenced lands have been conducted each year during July, at Navajo Mine. Cover is estimated using a line-intercept technique. Forty 30 m (98.4 feet) transects are used to characterize each of eight native plant communities. Production is estimated by clipping a 10 cm x 10 m (0.33 foot x 32.8 feet) area along each transect. Mean perennial cover after 12 years was 2.33% and the yearly value for cover has ranged from 0.82% to 4.27%. Mean perennial production for the same period was 234 lbs/acre and the yearly values ranged from 95 to 524 lbs/acre. The current revegetation success standard for reclamation at Navajo Mine is 5% perennial cover and 250 pounds per acre production. Since 1983, the cover value has never been met by the native communities, and the production standard has been met in only three years. A yearly normalized mean, reflecting the seasonal changes in climatic conditions, seems to be a better revegetation success standard than using a mean value representing the {open_quotes}long-term{close_quotes} conditions of a reference area.

  6. Cross-bedding Related Anisotropy and its Role in the Orientation of Joints in an Aeolian Sandstone

    NASA Astrophysics Data System (ADS)

    Deng, S.; Cilona, A.; Mapeli, C.; Panfilau, A.; Aydin, A.; Prasad, M.

    2014-12-01

    Previous research revealed that the cross-bedding related anisotropy in aeolian sandstones affects the orientation of compaction bands, also known as anticracks. We hypothesize that cross-bedding should a have similar influence on the orientation of the joints within the same rock at the same location. To test this hypothesis, we investigated the relationship between the cross-beds and the cross-bed package confined joints in the Jurassic aeolian Aztec Sandstone cropping out in the Valley of Fire State Park, Nevada. The field data demonstrates that the cross-bed package confined joints occur at high-angle to bedding and trend roughly parallel to the dip direction of the cross-beds. This shows that the cross-bed orientation and the associated anisotropy also exert a strong control on the formation and orientation of the joints. In order to characterize the anisotropy due to cross-bedding in the Aztec Sandstone, we measured the P-wave velocities parallel and perpendicular to bedding from 11 samples in the laboratory using a bench-top ultrasonic assembly. The measured P-wave anisotropy is about 13% on average. Based on these results, a numerical model based on the generalized Hooke's law for anisotropic materials is analyzed assuming the cross-bedded sandstone to be transversely isotropic. Using this model, we tested various cross-bed orientations as well as different strain boundary conditions (uniaxial, axisymmetric and triaxial). It is possible to define a boundary condition under which the modeled results roughly match with the observed relationship between cross-bed package confined joints and cross-beds. These results have important implications for fluid flow through aeolian sandstones in reservoirs and aquifers.

  7. Lower Cretaceous Avile Sandstone, Neuquen basin, Argentina - Exploration model for a lowstand clastic wedge in a back-arc basin

    SciTech Connect

    Ryer, T.A. )

    1991-03-01

    The Neuquen basin of western Argentina is a back-arc basin that was occupied by epeiric seas during much of Jurassic and Cretaceous time. The Avile Sandstone Member of the Agrio Formation records a pronounced but short-lived regression of the Agrio sea during middle Hauterivian (Early Cretaceous) time. Abrupt lowering of relative sea level resulted in emergence and erosion of the Agrio sea floor; shoreline and fluvial facies characteristic of the Centenario Formation shifted basinward. The Avile rests erosionally upon lower Agrio shale over a large area; well-sorted, porous sandstones within the member pinch out laterally against the base-Avile erosional surface. Avile deposition closed with an abrupt transgression of the shoreline to the approximate position it had occupied prior to the Avile regression. The transgressive deposits are carbonate rich, reflecting starvation of the basin as a consequence of sea-level rise. The Avile lowstand clastic wedge consists predominantly of sandstones deposited in fluvial to shallow-marine paleoenvironments; eolian sandstones probably constitute an important component in the eastern part of the area. The sandstones locally have excellent reservoir characteristics; they constitute the reservoirs in the Puesto Hernandez, Chihuido de la Sierra Negra, and Filo Morado fields. The pinch-out of the Avile lowstand clastic wedge has the potential to form stratigraphic traps in favorable structural positions. The depositional model indicates that there may be a viable stratigraphic play to be made along the Avile pinch-out in the deep, relatively undrilled, northwestern part of the Neuquen basin.

  8. New Perspectives on the Old Red Sandstone

    NASA Astrophysics Data System (ADS)

    Miall, Andrew D.

    The Old Red Sandstone is amongst the most distinctive and well-known stratigraphic units in the British Isles. It is mainly of Devonian age; in fact, its lower boundary was used to define the base of the Devonian until relatively recently and it was called "Old" back in the nineteenth century to distinguish it from a superficially similar succession of Triassic age named the New Red Sandstone. The Old Red Sandstone has long been known to be a non-marine syntectonic to post-tectonic deposit associated with the Caledonian Orogeny One of the most famous outcrops of the red sandstone is at Siccar Point in northeast England at one of several outcrops named "Hutton's unconformity" where it lies, with marked angularity on Silurian lithic sandstones and shales. It was at these outcrops, toward the end of the eigthteenth century that James Hutton first came to understand the meaning of angular unconformities as structures representing vast amounts of missing time during which major upheavals of the Earth's crust occurred.

  9. Architecture and development of the alluvial sediments of the Upper Jurassic Tordillo Formation in the Caada Ancha Valley, northern Neuqun Basin, Argentina

    NASA Astrophysics Data System (ADS)

    Lpez-Gmez, Jos; Martn-Chivelet, Javier; Palma, Ricardo M.

    2009-07-01

    The Upper Jurassic Tordillo Formation at Caada Ancha area, northern Neuqun Basin, Argentina, comprises a multi-stage suit of predominantly alluvial sediments that is heterolithic in nature. In that suit, several lithofacies, architectural elements, and bounding surfaces of different order have been identified and their lateral and vertical distribution characterized. This analysis allowed the differentiation of 3 main units (lower, middle and upper), 20 subunits (C-1 to C-20), and the characterization of their alluvial styles. The lower unit (which comprises subunits C-1 to C-4) is mainly formed by fine- to medium-grained sandstones, which become medium- to coarse-grained towards the top. These sandstones characterize settings ranging from floodplains with isolated, unconfined flows, to more complex, vertically stacked, multi-storey sheet sandstones of braided fluvial systems. The middle unit (C-5 to C-10) is dominated by pale brown-grey fine-to coarse-grained sands and medium size subangular to angular conglomerates, which reflect amalgamated complexes of sandstone sheets and downstream accretion macroforms. Remarkably, this alluvial sedimentation was episodically punctuated by volcaniclastic flows. The upper unit (C-11 to C-20) consists of finer sediments, mainly pink to white fine-to medium grained sandstones and red to green siltstones. Towards the top, bioturbation becomes important, and also the presence of volcanosedimentary flows is noticeable. Fluvial settings include braided sheet sandstones with waning flood deposits evolving to isolated high-sinuosity fluvial systems, with flash flood deposits. At the top of this unit, facies may suggest marine influence. Vertical changes in the fluvial style result from both climatic and tectonic controls. A semiarid to arid climate and the active tectonism linked to the eastward migration of the Andean volcanic arc determined major bounding surfaces, fluvial style evolution and the presence of the volcano-sedimentary deposits. Different stages of high and low subsidence rates has been deduced from the vertical stacking of sediments.

  10. Mixed fluvial systems of the Messak Sandstone, a deposit of the Nubian lithofacies, southwestern Libya

    NASA Astrophysics Data System (ADS)

    Lorenz, John C.

    1987-11-01

    The Messak Sandstone is a coarse-grained to pebbly, tabular-crossbedded deposit of the widespread nubian lithofacies. It was deposited during Late Jurassic and/or Early Cretaceous time at the northern edge of the Murzuq basin, in southwestern Libya. Although the sedimentary record is predominantly one of braided fluvial systems, a common subfacies within the formation is interpreted to record the passage of straight-crested sand waves across laterally migrating point bars in sinuous rivers, similar to parts of the modern Ganga and Yamuna rivers. Because the sand waves were larger on the lower parts of the point bar, lateral migration created diagnostic thinning-upward cosets of tabular crossbeds, as well as fining-upward grain-size trends. Common thick, interbedded claystones, deposited in associated paludal and lacustrine environments, and high variance in crossbed dispersion patterns, also suggest the local presence of sinuous fluvial systems within the overall braided regime. The Messak Sandstone contains some of the features that led to the proposal of an unconventional low-sinuosity fluvial environment for the Nubian lithofacies in Egypt, and the continuously high water levels of this model may explain channel-scale clay drapes and overturned crossbeds in the Messak. However, most of the Messak characteristics are incompatible with a low-sinuosity model, suggesting instead that the fluvial channels in the Murzuq basin alternated between braided and high-sinuosity channel patterns.

  11. Mechanism of formation of wiggly compaction bands in porous sandstone: 1. Observations and conceptual model

    NASA Astrophysics Data System (ADS)

    Liu, Chun; Pollard, David D.; Deng, Shang; Aydin, Atilla

    2015-12-01

    Field observations are combined with microscopic analyses to investigate the mechanism of formation of wiggly compaction bands (CBs) in the porous Jurassic aeolian Aztec Sandstone exposed at Valley of Fire State Park, Nevada. Among the three types of CBs (T1, T2, and T3), we focused on the wiggly CBs (T3), which show a chevron (T31) or wavy (T32) pattern with typical corner angles of approximately 90 or 130, respectively. Where corner angles of wiggly CBs increase to 180, they become straight CBs (T33). Image analyses of thin sections using an optical microscope show host rock porosity increases downslope in this dune, and the predominant type of wiggly CBs also varies from chevron to straight CBs. Specifically, band type varies continuously from chevron to wavy to straight where the porosity and grain sorting of the host rock increase systematically. Based on the crack and anticrack models, we infer that the change from chevron to straight CBs is due to increasing failure angle of the sandstone and this may correlate with increasing grain sorting. Wavy CBs with intermediate failure angle and host rock porosity are an intermediate stage between chevron and straight CBs. Previous sedimentological studies also have suggested that grain size and sorting degree increase downslope on the downwind side of sand dunes due to a sieving process of the wind-blown grains. Therefore, the transition of wiggly CB types in this regard correlates with increasing sorting and perhaps with increasing porosity downslope.

  12. DEFORMATION AND FRACTURE OF POORLY CONSOLIDATED MEDIA - Borehole Failure Mechanisms in High-Porosity Sandstone

    SciTech Connect

    Bezalel c. Haimson

    2005-06-10

    We investigated failure mechanisms around boreholes and the formation of borehole breakouts in high-porosity sandstone, with particular interest to grain-scale micromechanics of failure leading to the hitherto unrecognized fracture-like borehole breakouts and apparent compaction band formation in poorly consolidated granular materials. We also looked at a variety of drilling-related factors that contribute to the type, size and shape of borehole breakouts. The objective was to assess their effect on the ability to establish correlations between breakout geometry and in situ stress magnitudes, as well as on borehole stability prediction, and hydrocarbon/water extraction in general. We identified two classes of medium to high porosity (12-30%) sandstones, arkosic, consisting of 50-70% quartz and 15 to 50% feldspar, and quartz-rich sandstones, in which quartz grain contents varied from 90 to 100%. In arkose sandstones critical far-field stress magnitudes induced compressive failure around boreholes in the form of V-shaped (dog-eared) breakouts, the result of dilatant intra-and trans-granular microcracking subparallel to both the maximum horizontal far-field stress and to the borehole wall. On the other hand, boreholes in quartz-rich sandstones failed by developing fracture-like breakouts. These are long and very narrow (several grain diameters) tabular failure zones perpendicular to the maximum stress. Evidence provided mainly by SEM observations suggests a failure process initiated by localized grain-bond loosening along the least horizontal far-field stress springline, the packing of these grains into a lower porosity compaction band resembling those discovered in Navajo and Aztec sandstones, and the emptying of the loosened grains by the circulating drilling fluid starting from the borehole wall. Although the immediate several grain layers at the breakout tip often contain some cracked or even crushed grains, the failure mechanism enabled by the formation of the compaction band is largely non-dilatant, a major departure from the dilatant mechanism observed in Tablerock sandstone. The experimental results suggest that unlike our previous assertion, the strength of grain bonding and the mineral composition, rather than the porosity, are major factors in the formation of compaction bands and the ensuing fracture-like breakouts. Some breakout dimensions in all rocks were correlatable to the far-field principal stresses, and could potentially be used (in conjunction with other information) as indicators of their magnitudes. However, we found that several factors can significantly influence breakout geometry. Larger boreholes and increased drilling-fluid flow rates produce longer fracture-like breakouts, suggesting that breakouts in field-scale wellbores could reach considerable lengths. On the other hand, increased drilling-fluid weight and increased drill-bit penetration rate resulted in a decrease in breakout length. These results indicate that breakout growth can be controlled to some degree by manipulating drilling variables. Realizing how drilling variables impact borehole breakout formation is important in understanding the process by which breakouts form and their potential use as indicators of the far-field in situ stress magnitudes and as sources of sand production. As our research indicates, the final breakout size and mechanism of formation can be a function of several variables and conditions, meaning there is still much to be understood about this phenomenon.

  13. Sedimentary evolution and palaeogeography of mid-Jurassic deposits of the Central High Atlas, Morocco

    NASA Astrophysics Data System (ADS)

    Ait Addi, Abdellah; Chafiki, Driss

    2013-08-01

    In the axis of the Moroccan Central High Atlas rift basin, Toarcian-Middle Jurassic deposits, excepting the early Toarcian Tagoudite Formation, are represented by two formations - Agoudim and Tazigzaout - comprising clays, marls and limestones. On the margins of the basin, the lateral equivalents of these two formations are dolostone-dominated and show the lithological and environmental characteristics of the Bin El Ouidane Group recognized in the NW part of the Central High Atlas (Beni-Mellal/Azilal area). This group is overlain by clays and limestones of the Tillouguite Formation and by Bathonian red beds (silts, sandstones and conglomerates) of the Anemzi Formation. From the Toarcian to Aalenian (Agoudim Members I and II) the contrasting palaeogeographical evolution is marked by a relatively deep central basin bordered by shallow marine carbonates. The Aalenian-Lower Bajocian interval (Agoudim Member II) contains lenticular biodetritic limestones within hemipelagic deposits. These facies resulted from recurrent faulting (tectonic pulses), which was at the origin of the individualization of a series of ridges and depocentres within the High Atlas trough. During the Bajocian (Agoudim Members III and IV) the palaeogeography became homogeneous across the Central High Atlas and corresponded to a carbonate ramp with coral patch reefs. During the ?Late Bajocian (Tazigzaout Lower Member) a new palaeogeography developed with reappearance of the central depocentres. During the latest Bajocian-earliest Bathonian (Tazigzaout Upper Member) a very homogeneous carbonate ramp was again established. These times of uniform palaeogeography are interpreted as relative stable tectonic periods that were progressive stages leading to the ending of the Toarcian-Middle Jurassic sedimentary cycles in the Central High Atlas rift basin of Morocco.

  14. Pangaean climate during the Early Jurassic: GCM simulations and the sedimentary record of paleoclimate

    SciTech Connect

    Chandler, M.A.; Rind, D.; Ruedy, R.

    1992-05-01

    Results from new simulations of the Early Jurassic climate show that increased ocean heat transport may have been the primary force generating warmer climates during the past 180 m.y. The simulations, conducted using the general circulation model (GCM) at the Goddard Institute for Space Studies, include realistic representations of paleocontinental distribution, topography, epeiric seas, and vegetation, in order to facilitate comparisons between model results and paleoclimate data. three major features of the simulated Early Jurassic climate include the following. (1) A global warming, compared to the present, of 5 {degrees}C to 10 {degrees}C, with temperature increases at high latitudes five times this global average. Average summer temperatures exceed 35 {degrees}C in low-latitude regions of western Pangaea where eolian sandstones testify to the presence of vast deserts. (2) Simulated precipitation and evaporation patterns agree closely with the moisture distribution interpreted from evaporites, and coal deposits. High rainfall rates are associated primarily with monsoons that originate over the warm Tethys Ocean. Unlike the {open_quotes}megamonsoons{close_quotes} proposed in previous studies, these systems are found to be associated with localized pressure cells whose positions are controlled by topography and coastal geography. (3) Decreases in planetary albedo, occurring because of reductions in sea ice, snow cover, and low clouds, and increases in atmospheric water vapor are the positive climate feedbacks that amplify the global warming. Similar to other Mesozoic climate simulations, our model finds that large seasonal temperature fluctuations occurred over mid- and high-latitude continental interiors, refuting paleoclimate evidence that suggests more equable conditions. 101 refs., 9 figs., 3 tabs.

  15. Vertebrate fossils and trace fossils in Upper Jurassic-Lower cretaceous red beds in the Atacama region, Chile

    NASA Astrophysics Data System (ADS)

    Bell, C. M.; Suárez, M.

    Pterosaur, dinosaur, and crocodile bones are recorded here for the first time in Upper Jurassic-Lower Cretaceous red beds in the Atacama region east of Copiapó, Chile. Trace fossils produced by vertebrate animals include the footprints of theropod dinosaurs and the depressions of sandstone laminae interpreted as burrows and foot impressions. The fossils occur in the 1500-meter-thick Quebrada Monardes Formation, which consists predominantly of the aeolian and alluvial deposits of a semi-arid terrestrial environment. Vertebrate fossils are very rare in Chile. Dinosaur bones and footprints have previously been recorded at only seven locations, and pterosaur remains at only one location. The newly discovered dinosaur bones are the oldest to be described in Chile.

  16. Solar membrane distillation: desalination for the Navajo Nation.

    PubMed

    Karanikola, Vasiliki; Corral, Andrea F; Mette, Patrick; Jiang, Hua; Arnoldand, Robert G; Ela, Wendell P

    2014-01-01

    Provision of clean water is among the most serious, long-term challenges in the world. To an ever increasing degree, sustainable water supply depends on the utilization of water of impaired initial quality. This is particularly true in developing nations and in water-stressed areas such as the American Southwest. One clear example is the Navajo Nation. The reservation covers 27,000 square miles, mainly in northeastern Arizona. Low population density coupled with water scarcity and impairment makes provision of clean water particularly challenging. The Navajos rely primarily on ground water, which is often present in deep aquifers or of brackish quality. Commonly, reverse osmosis (RO) is chosen to desalinate brackish ground water, since RO costs are competitive with those of thermal desalination, even for seawater applications. However, both conventional thermal distillation and RO are energy intensive, complex processes that discourage decentralized or rural implementation. In addition, both technologies demand technical experience for operation and maintenance, and are susceptible to scaling and fouling unless extensive feed pretreatment is employed. Membrane distillation (MD), driven by vapor pressure gradients, can potentially overcome many of these drawbacks. MD can operate using low-grade, sub-boiling sources of heat and does not require extensive operational experience. This presentation discusses a project on the Navajo Nation, Arizona (Native American tribal lands) that is designed to investigate and deploy an autonomous (off-grid) system to pump and treat brackish groundwater using solar energy. ?ench-scale, hollow fiber MD experiment results showed permeate water fluxes from 21 L/m2d can be achieved with transmembrane temperature differences between 40 and 80?C. Tests run with various feed salt concentrations indicate that the permeate flux decreases only about 25% as the concentration increases from 0 to 14% (w/w), which is four times seawater salt concentration. The quality of the permeate water remains constant at about 1 mg/L regardless of the changes in the influent salt concentration. A nine-month MD field trial, using hollow fiber membranes and completely off-the-shelf components demonstrated that a scaled-up solar-driven MD system was practical and economically viable. Based on these results, a pilot scale unit will be constructed and deployed on the tribal lands. PMID:24552961

  17. Root grooves on sandstone bedrock, Ouachita Mountains

    NASA Astrophysics Data System (ADS)

    Turkington, A. T.

    2010-12-01

    This study presents findings demonstrating the existence of root grooves on siliceous sandstone. It is clear from biochemical studies that weathering in ecosystems with vigorous plant growth is more rapid than in non-vegetated areas, and previous studies of the interactions between tree roots and bedrock have demonstrated the importance of trees in breaking down bedrock through biophysical and biomechanical processes, including treethrow. However, the development of root grooves has rarely been reported on bedrock other than limestone or calcareous substrate. This poster will show the existence of tree root grooves on siliceous sandstone in the Ouachita Mountains, and will discuss the processes that have led to their genesis and development.

  18. Diagenesis and fluid flow in the San Juan Basin, New Mexico - regional zonation in the mineralogy and stable isotope composition of clay minerals in sandstone.

    USGS Publications Warehouse

    Whitney, G.; Northrop, H.R.

    1987-01-01

    The Westwater Canyon Member of the Upper Jurassic Morrison Formation is a relatively homogeneous, hydrologically continuous 100-m-thick sequence of massive fluvial sandstone, bounded above and below by relatively heterogeneous, hydrologically discontinuous units and has served as a primary conduit for fluids within this stratigraphic interval. Patterns of mineral-fluid reactions suggest a basinwide hydrologic regime in which warm, evolved fluids migrated up-dip from the center of the basin under the influence of a regional hydraulic head. -from Authors

  19. Main phytostratigraphic boundaries in the Jurassic deposits of Western Siberia

    NASA Astrophysics Data System (ADS)

    Mogutcheva, N. K.

    2014-05-01

    The study of the large collections of plant remains gained from cores of numerous boreholes drilled in Western Siberia made it possible to determine the taxonomic composition of the Jurassic flora of this region, the stages of its evolution, and the sequence of floral assemblages, which characterize the regional stratigraphic horizons indirectly correlated via series of parallel faunal, microfaunal, spore and pollen zonal scales with a general stratigraphic scale. The compositions of floral assemblages was established in the Hettangian-lower part of the upper Pliensbachian, upper part of the upper Pliensbachian, lower Toarcian, upper Toarcian, Aalenian, Bajocian, Bathonian, and Callovian-Oxfordian sediments. Criteria were elaborated to substantiate the Triassic-Jurassic and Lower-Middle Jurassic boundaries. Lithologically and biostrati-graphically, the Middle-Upper Jurassic boundary is poorly expressed.

  20. A review of Yellow Dirt: A Poisoned Land and the Betrayal of the Navajos.

    PubMed

    Adams, Nicole

    2015-05-01

    Yellow Dirt is a thorough account of the past and present state of the Navajo Nation with regards to uranium mining. Through a journalistic approach Judy Pasternak weaves the story of the betrayal of the Navajo people. This book highlights the impact of environment on health and this review calls all nurses to be aware of these impacts and incorporate this type of knowledge into their practice. PMID:25172455

  1. Upper Jurassic and Lower Cretaceous facies relationships in a passive margin basin, western North Atlantic

    SciTech Connect

    Prather, B.E.

    1988-02-01

    Correlation of facies from hydrocarbon-bearing continental and transitional marine sandstones to time-equivalent high-energy shelf-margin carbonates provide insight into hydrocarbon habitats of the Baltimore Canyon basin. These facies occur within a thick (> 10,000 ft) prograded wedge of shelf sediments in this passive margin basin. Wells drilled to test structural closures in shallow-water (< 600 ft) areas of Baltimore Canyon penetrate clastic facies which are time-equivalent to the downdip carbonate facies tested in deep-water wells. Numerous hydrocarbon shows, including a noncommercial gas and gas-condensate accumulation, occur with sandstone units that were deposited in prograding continental/fluvial and transitional marine environments located updip of the Oxfordian/Kimmeridgian carbonate shelf edge. The continental and transitional facies are overlain by a fine-grained deltaic complex which forms a regionally extensive top seal unit. The deltaic complex was deposited during aggradation of the Kimmeridgian through Berriasian shelf-margin carbonates penetrated by the deep-water wells. Deep-water wells (> 5000 ft) drilled off the continental shelf edge to test large structural closures along the downdip termination of the Upper Jurassic/Lower Cretaceous carbonate shelf edge encountered no significant hydrocarbon shows. Reservoir rocks in these wells consist of (1) oolite grainstone which was deposited within a shoal-water complex located at the Aptian shelf edge, and (2) coral-stromatoporoid grainstone and boundstone which formed an aggraded shelf-margin complex located at the Kimmeridgian through Berriasian shelf edge. Structural closures with reservoir and top seals are present in both updip and downdip trends. The absence of hydrocarbon shows in downdip carbonate reservoirs suggests a lack of source rocks available to charge objectives at the shelf margin.

  2. Natural gas plays in Jurassic reservoirs of southwestern Alabama and the Florida panhandle area

    SciTech Connect

    Mancini, E.A. Univ. of Alabama, Tuscaloosa ); Mink, R.M.; Tew, B.H.; Bearden, B.L. )

    1990-09-01

    Three Jurassic natural gas trends can be delineated in Alabama and the Florida panhandle area. They include a deep natural gas trend, a natural gas and condensate trend, and an oil and associated natural gas trend. These trends are recognized by hydrocarbon types, basinal position, and relationship to regional structural features. Within these natural gas trends, at least eight distinct natural gas plays can be identified. These plays are recognized by characteristic petroleum traps and reservoirs. The deep natural gas trend includes the Mobile Bay area play, which is characterized by faulted salt anticlines associated with the Lower Mobile Bay fault system and Norphlet eolian sandstone reservoirs exhibiting primary and secondary porosity at depths exceeding 20,000 ft. The natural gas and condensate trend includes the Mississippi Interior Salt basin play, Mobile graben play, Wiggins arch flank play, and the Pollard fault system play. The Mississippi Interior Salt basin play is typified by salt anticlines associated with salt tectonism in the Mississippi Interior Salt basin and Smackover dolomitized peloidal and pelmoldic grainstone and packstone reservoirs at depths of approximately 16,000 ft. The Mobile graben play is exemplified by faulted salt anticlines associated with the Mobile graben and Smackover dolostone reservoirs at depths of approximately 18,000 ft. The Wiggins arch flank play is characterized by structural traps consisting of salt anticlines associated with stratigraphic thinning and Smackover dolostone reservoirs at depths of approximately 18,000 ft. The Pollard fault system play is typified by combination petroleum traps. The structural component is associated with the Pollard fault system and reservoirs at depths of approximately 15,000 ft. These reservoirs are dominantly Smackover dolomitized oomoldic and pelmoldic grainstones and packstones and Norphlet marine, eolian, and wadi sandstones exhibiting primary and secondary porosity.

  3. Dinosaur ichnofauna of the Upper Jurassic/Lower Cretaceous of the Paraná Basin (Brazil and Uruguay)

    NASA Astrophysics Data System (ADS)

    Francischini, H.; Dentzien–Dias, P. C.; Fernandes, M. A.; Schultz, C. L.

    2015-11-01

    Upper Jurassic and Lower Cretaceous sedimentary layers are represented in the Brazilian Paraná Basin by the fluvio-aeolian Guará Formation and the Botucatu Formation palaeoerg, respectively, overlapped by the volcanic Serra Geral Formation. In Uruguay, the corresponding sedimentary units are named Batoví and Rivera Members (both from the Tacuarembó Formation), and the lava flows constitute the Arapey Formation (also in Paraná Basin). Despite the lack of body fossils in the mentioned Brazilian formations, Guará/Batoví dinosaur fauna is composed of theropod, ornithopod and wide-gauge sauropod tracks and isolated footprints, as well as theropod teeth. In turn, the Botucatu/Rivera dinosaur fauna is represented by theropod and ornithopod ichnofossils smaller than those from the underlying units. The analysis of these dinosaur ichnological records and comparisons with other global Mesozoic ichnofauna indicates that there is a size reduction in dinosaur fauna in the more arid Botucatu/Rivera environment, which is dominated by aeolian dunes. The absence of sauropod trackways in the Botucatu Sandstone fits with the increasingly arid conditions because it is difficult for heavy animals to walk on sandy dunes, as well as to obtain the required amount of food resources. This comparison between the Upper Jurassic and Lower Cretaceous dinosaur fauna in south Brazil and Uruguay demonstrates the influence of aridization on the size of animals occupying each habitat.

  4. Navajo Generating Station and Clean-Energy Alternatives: Options for Renewables

    SciTech Connect

    Hurlbut, D. J.; Haase, S.; Turchi, C. S.; Burman, K.

    2012-06-01

    In January 2012, the National Renewable Energy Laboratory delivered to the Department of the Interior the first part of a study on Navajo Generating Station (Navajo GS) and the likely impacts of BART compliance options. That document establishes a comprehensive baseline for the analysis of clean energy alternatives, and their ability to achieve benefits similar to those that Navajo GS currently provides. This analysis is a supplement to NREL's January 2012 study. It provides a high level examination of several clean energy alternatives, based on the previous analysis. Each has particular characteristics affecting its relevance as an alternative to Navajo GS. It is assumed that the development of any alternative resource (or portfolio of resources) to replace all or a portion of Navajo GS would occur at the end of a staged transition plan designed to reduce economic disruption. We assume that replacing the federal government's 24.3% share of Navajo GS would be a cooperative responsibility of both the U.S. Bureau of Reclamation (USBR) and the Central Arizona Water Conservation District (CAWCD).

  5. Healthy Gardens/Healthy Lives: Navajo perceptions of growing food locally to prevent diabetes and cancer

    PubMed Central

    Beresford, Shirley A.A.; Ornelas, India; Topaha, Carmelita; Becenti, Tonia; Thomas, Dustin; Vela, Jaime G.

    2013-01-01

    Poor access to nutritious foods, departure from traditional diets, and reduced physical activity are associated with a rise in type-2 diabetes and certain types of cancers among the Navajo. Diabetes in particular is of concern because of its increased prevalence among Navajo youth. Gardening can successfully address issues of poor availability of fruits and vegetables and offer many other social and health benefits. Our assessment aimed to determine Navajo attitudes about gardening and health in San Juan County, New Mexico. We conducted seven focus groups (including 31 people) to assess knowledge and attitudes related to gardening, and uncover barriers and facilitators to participation in a garden project. Each group session was moderated by two Navajo students. Transcripts revealed that many Navajo are aware of adverse health issues, predominantly obesity and diabetes, which occur on the reservation. Participants expressed a preference for educational approaches that incorporated cultural traditions, respect for elders, use of visual aids and experiential learning. Several social and agronomic barriers to gardening were also mentioned. Results suggested a broad interest in promoting gardening especially to reduce the risk of diabetes with the added value of enhancing social capital in Navajo communities. PMID:23855020

  6. Healthy gardens/healthy lives: Navajo perceptions of growing food locally to prevent diabetes and cancer.

    PubMed

    Lombard, Kevin A; Beresford, Shirley A A; Ornelas, India J; Topaha, Carmelita; Becenti, Tonia; Thomas, Dustin; Vela, Jaime G

    2014-03-01

    Poor access to nutritious foods, departure from traditional diets, and reduced physical activity are associated with a rise in type 2 diabetes and certain types of cancers among the Navajo. Diabetes in particular is of concern because of its increased prevalence among Navajo youth. Gardening can successfully address issues of poor availability of fruits and vegetables and offer many other social and health benefits. Our assessment aimed to determine Navajo attitudes about gardening and health in San Juan County, New Mexico. We conducted seven focus groups (including 31 people) to assess knowledge and attitudes related to gardening and uncover barriers and facilitators to participation in a garden project. Each group session was moderated by two Navajo students. Transcripts revealed that many Navajo are aware of adverse health issues that occur on the reservation, predominantly obesity and diabetes. Participants expressed a preference for educational approaches that incorporated cultural traditions, respect for elders, use of visual aids, and experiential learning. Several social and agronomic barriers to gardening were also mentioned. Results suggested a broad interest in promoting gardening especially to reduce the risk of diabetes with the added value of enhancing social capital in Navajo communities. PMID:23855020

  7. Fractures and stresses in Bone Spring sandstones

    SciTech Connect

    Lorenz, J.C.; Warpinski, N.R.; Sattler, A.R.; Northrop, D.A.

    1990-09-01

    This project is a collaboration between Sandia National Laboratories and Harvey E. Yates Company being conducted under the auspices of the Oil Recovery Technology Partnership. The project seeks to apply perspectives related to the effects of natural fractures, stress, and sedimentology to the simulation and production of low-permeability gas reservoirs to low-permeability oil reservoirs as typified by the Bone Spring sandstones of the Permian Basin, southeast New Mexico. This report presents the results and analysis obtained in 1989 from 233 ft of oriented core, comprehensive suite of logs, various in situ stress measurements, and detailed well tests conducted in conjunction with the drilling of two development wells. Natural fractures were observed in core and logs in the interbed carbonates, but there was no direct evidence of fractures in the sandstones. However, production tests of the sandstones indicated permeabilities and behavior typical of a dual porosity reservoir. A general northeast trend for the maximum principal horizontal stress was observed in an elastic strain recovery measurements and in strikes of drilling-induced fractures; this direction is subparallel to the principal fracture trend observed in the interbed carbonates. Many of the results presented are believed to be new information for the Bone Spring sandstones. 57 figs., 18 tabs.

  8. Late Jurassic plutonism in the southwest U.S. Cordillera

    USGS Publications Warehouse

    Barth, A.P.; Wooden, J.L.; Howard, K.A.; Richards, J.L.

    2008-01-01

    Although plate reconstructions suggest that subduction was an approximately steady-state process from the mid-Mesozoic through the early Tertiary, recent precise geochronologic studies suggest highly episodic emplacement of voluminous continental-margin batholiths in the U.S. Cordillera. In central and southern California and western Arizona, major episodes of batholithic magmatism are known to have occurred in Permian-Triassic, Middle Jurassic, and late Early to Late Cretaceous time. However, recent studies of forearc-basin and continental-interior sediments suggest that Late Jurassic time was probably also a period of significant magmatism, although few dated plutons of this age have been recognized. We describe a belt of Late Jurassic plutonic and hypabyssal rocks at least 200 km in length that extends from the northwestern Mojave Desert through the Transverse Ranges. The belt lies outboard of both the voluminous Middle Jurassic arc and the ca. 148 Ma Independence dike swarm at these latitudes. The plutons include two intrusive suites emplaced between 157 and 149 Ma: a calc-alkaline suite compositionally unlike Permian-Triassic and Middle Jurassic mon-zonitic suites but similar to Late Cretaceous arc plutons emplaced across this region, and a contemporaneous but not comagmatic alkaline suite. The Late Jurassic was thus a time of both tectonic and magmatic transitions in the southern Cordillera. ?? 2008 The Geological Society of America.

  9. Triassic/Jurassic faulting patterns of Conecuh Ridge, southwest Alabama

    SciTech Connect

    Hutley, J.K.

    1985-02-01

    Two major fault systems influenced Jurassic structure and deposition on the Conecuh Ridge, southwest Alabama. Identification and dating of these fault systems are based on seismic-stratigraphic interpretation of a 7-township grid in Monroe and Conecuh Counties. Relative time of faulting is determined by fault geometry and by formation isopachs and isochrons. Smackover and Norphlet Formations, both Late Jurassic in age, are mappable seismic reflectors and are thus reliable for seismicstratigraphic dating. The earlier of the 2 fault systems is a series of horsts and grabens that trends northeast-southwest and is Late Triassic to Early Jurassic in age. The system formed in response to tensional stress associated with the opening of the Atlantic Ocean. The resulting topography was a series of northeast-southwest-trending ridges. Upper Triassic Eagle Mills and Jurassic Werner Formations were deposited in the grabens. The later fault system is also a series of horsts and grabens trending perpendicular to the first. This system was caused by tensional stress related to a pulse in the opening of the Gulf of Mexico. Faulting began in Early Jurassic and continued into Late Jurassic, becoming progressively younger basinward. At the basin margin, faulting produced a very irregular shoreline. Submerged horst blocks became centers for shoaling or carbonate buildups. Today, these blocks are exploration targets in southwest Alabama.

  10. Total petroleum systems of the Bonaparte Gulf Basin area, Australia; Jurassic, Early Cretaceous-Mesozoic; Keyling, Hyland Bay-Permian; Milligans-Carboniferous, Permian

    USGS Publications Warehouse

    Bishop, M.G.

    1999-01-01

    The Bonaparte Gulf Basin Province (USGS #3910) of northern Australia contains three important hydrocarbon source-rock intervals. The oldest source-rock interval and associated reservoir rocks is the Milligans-Carboniferous, Permian petroleum system. This petroleum system is located at the southern end of Joseph Bonaparte Gulf and includes both onshore and offshore areas within a northwest to southeast trending Paleozoic rift that was initiated in the Devonian. The Milligans Formation is a Carboniferous marine shale that sources accumulations of both oil and gas in Carboniferous and Permian deltaic, marine shelf carbonate, and shallow to deep marine sandstones. The second petroleum system in the Paleozoic rift is the Keyling, Hyland Bay-Permian. Source rocks include Lower Permian Keyling Formation delta-plain coals and marginal marine shales combined with Upper Permian Hyland Bay Formation prodelta shales. These source-rock intervals provide gas and condensate for fluvial, deltaic, and shallow marine sandstone reservoirs primarily within several members of the Hyland Bay Formation. The Keyling, Hyland Bay-Permian petroleum system is located in the Joseph Bonaparte Gulf, north of the Milligans-Carboniferous, Permian petroleum system, and may extend northwest under the Vulcan graben sub-basin. The third and youngest petroleum system is the Jurassic, Early Cretaceous-Mesozoic system that is located seaward of Joseph Bonaparte Gulf on the Australian continental shelf, and trends southwest-northeast. Source-rock intervals in the Vulcan graben sub-basin include deltaic mudstones of the Middle Jurassic Plover Formation and organic-rich marine shales of the Upper Jurassic Vulcan Formation and Lower Cretaceous Echuca Shoals Formation. These intervals produce gas, oil, and condensate that accumulates in, shallow- to deep-marine sandstone reservoirs of the Challis and Vulcan Formations of Jurassic to Cretaceous age. Organic-rich, marginal marine claystones and coals of the Plover Formation (Lower to Upper Jurassic), combined with marine claystones of the Flamingo Group and Darwin Formation (Upper Jurassic to Lower Cretaceous) comprise the source rocks for the remaining area of the system. These claystones and coals source oil, gas, and condensate accumulations in reservoirs of continental to marine sandstones of the Plover Formation and Flamingo Group. Shales of the regionally distributed Lower Cretaceous Bathurst Island Group and intraformational shales act as seals for hydrocarbons trapped in anticlines and fault blocks, which are the major traps of the province. Production in the Bonaparte Gulf Basin Province began in 1986 using floating production facilities, and had been limited to three offshore fields located in the Vulcan graben sub-basin. Cumulative production from these fields totaled more than 124 million barrels of oil before the facilities were removed after production fell substantially in 1995. Production began in 1998 from three offshore wells in the Zone of Cooperation through floating production facilities. After forty years of exploration, a new infrastructure of pipelines and facilities are planned to tap already discovered offshore reserves and to support additional development.

  11. Spectral Induced Polarization of Sandstones: Temperature Effects

    NASA Astrophysics Data System (ADS)

    Binley, A.; Kruschwitz, S.; Lesmes, D.

    2007-12-01

    There is growing interest in the use of spectral induced polarization (SIP) for a wide range of environmental applications, in particular those focused on hydrogeological investigations. Recent experimental work has demonstrated that the mean relaxation time of electrical impedance spectra measured in sandstones is linked to the grain surface area and strongly correlated to some measure of a dominant pore throat size. Such empirically derived relationships lead to potential models of SIP - hydraulic conductivity, which has immense value for the hydrological community. Furthermore, the links between surface area and electrical response may lead to other, equally exciting, applications, such as in characterizing geochemical reactivity of sediments. However, there is a need to understand the fundamental behavior of SIP in such porous media in order for such models to be applied usefully. In an attempt to address this, we focus here on the influence of temperature on the SIP behavior of a range of sandstones. Classical models of dielectric dispersion in colloids have proposed direct inverse relationships between relaxation time and temperature. Through a series of experimental trials we have studied this behavior: examining the impedance spectra (in the 1 mHz to 1 kHz range) of four different sandstones over a temperature range of 5 to 30 degrees Celsius. Analysis of the spectra with the widely used Pelton Cole-Cole model has confirmed hypothesized effects on a mean relaxation time but revealed that the responses to temperature change is a function of physical properties of the sandstone. In addition, the analysis has illustrated how temperature effects on surface complex conductivity of the sandstones differ as a function of pore fluid and formation factor. The results add to the growing experimental evidence of controls on spectral impedance in porous media and help ascertain generalized petrophysical models for a wide range of applications.

  12. Nature of the Jurassic Magnetic Quiet Zone

    NASA Astrophysics Data System (ADS)

    Tominaga, Masako; Tivey, Maurice A.; Sager, William W.

    2015-10-01

    The nature of the Jurassic Quiet Zone (JQZ), a region of low-amplitude oceanic magnetic anomalies, has been a long-standing debate with implications for the history and behavior of the Earth's geomagnetic field and plate tectonics. To understand the origin of the JQZ, we studied high-resolution sea surface magnetic anomalies from the Hawaiian magnetic lineations and correlated them with the Japanese magnetic lineations. The comparison shows the following: (i) excellent correlation of anomaly shapes from M29 to M42; (ii) remarkable similarity of anomaly amplitude envelope, which decreases back in time from M19 to M38, with a minimum at M41, then increases back in time from M42; and (iii) refined locations of pre-M25 lineations in the Hawaiian lineation set. Based on these correlations, our study presents evidence of regionally and possibly globally coherent pre-M29 magnetic anomalies in the JQZ and a robust extension of Hawaiian isochrons back to M42 in the Pacific crust.

  13. Jurassic sequence stratigraphy in Mississippi interior salt basin: an aid to petroleum exploration in eastern Gulf of Mexico area

    SciTech Connect

    Mancini, E.A.; Mink, R.M.; Tew, B.H.

    1988-02-01

    An understanding of sequence stratigraphy of Jurassic units in onshore basins can serve as an aid to identify potential petroleum reservoir and source rocks in the eastern Gulf of Mexico area. Three depositional sequences associated with cycles of eustatic sea level change and coastal onlap have been identified in the Mississippi Interior Salt basin. Three depositional sequences probably correspond to the J2.4, J3.1, and J3.2 sequences of Vail et al for Callovian through Kimmeridgian strata. In the Mississippi Interior salt basin, the lower depositional sequence is bounded by a basal type 2 unconformity and an upper type 2 unconformity in the Callovian. This sequence includes Louann evaporites (transgressive), Pine Hill anhydrites and shales (condensed section), and Norphlet eolian sandstones (highstand regressive). The middle depositional sequence reflects relative sea level rise in the late Callovian. This sequence includes Norphlet marine sandstones and lower Smackover packstones and mudstones (transgressive), middle Smackover mudstones (condensed section), and upper Smackover grainstones and anhydrites (highstand regressive).

  14. Architectural elements and bounding surfaces in fluvial deposits: anatomy of the Kayenta formation (lower jurassic), Southwest Colorado

    NASA Astrophysics Data System (ADS)

    Miall, Andrew D.

    1988-03-01

    Three well-exposed outcrops in the Kayenta Formation (Lower Jurassic), near Dove Creek in southwestern Colorado, were studied using lateral profiles, in order to test recent regarding architectural-element analysis and the classification and interpretation of internal bounding surfaces. Examination of bounding surfaces within and between elements in the Kayenta outcrops raises problems in applying the three-fold classification of Allen (1983). Enlarging this classification to a six-fold hierarchy permits the discrimination of surfaces intermediate between Allen's second- and third-order types, corresponding to the upper bounding surfaces of macroforms, and internal erosional "reactivation" surfaces within the macroforms. Examples of the first five types of surface occur in the Kayenta outcrops at Dove Creek. The new classifications is offered as a general solution to the problem of description of complex, three-dimensional fluvial sandstone bodies. The Kayenta Formation at Dove Creek consists of a multistorey sandstone body, including the deposits of lateral- and downstream-accreted macroforms. The storeys show no internal cyclicity, neither within individual elements nor through the overall vertical thickness of the formation. Low paleocurrent variance indicates low sinuosity flow, whereas macroform geometry and orientation suggest low to moderate sinuosity. The many internal minor erosion surfaces draped with mud and followed by intraclast breccias imply frequent rapid stage fluctuation, consistent with variable (seasonal? monsonal? ephemmeral?) flow. The results suggest a fluvial architecture similar to that of the South Saskatchewan River, through with a three-dimensional geometry unlike that interpreted from surface studies of that river.

  15. Stratigraphy and facies architecture of the fluvial aeolian lacustrine Sergi Formation (Upper Jurassic), Recncavo Basin, Brazil

    NASA Astrophysics Data System (ADS)

    Scherer, Claiton M. S.; Lavina, Ernesto L. C.; Dias Filho, Dorval C.; Oliveira, Flvio M.; Bongiolo, Daniela E.; Aguiar, Eduardo S.

    2007-02-01

    The Sergi Formation encompasses an upper Jurassic fluvial-eolian-lacustrine succession deposited within a wide intracratonic basin. Its sand bodies represent the largest and more important reservoirs in the Recncavo Basin, hosting 362 million m 3 of oil in place. The main goal of this paper is to provide a detailed stratigraphic analysis of the Sergi Formation based on core and outcrop data. It was achieved through the recognition and correlation of regional surfaces that have allowed the subdivision of this unit into distinct depositional sequences, and the reconstruction of its depositional history. The studied succession can be subdivided into three unconformity-bounded sequences. Sequence I is composed of lacustrine mudstone at its base, which is overlain by fine- to medium-grained sandstone related to aeolian dune and sand sheet and ephemeral fluvial stream deposits. Fluvial strata indicate northeastward-flowing streams whereas aeolian dune deposits suggest the action of southwestward-blowing winds. The regional unconformity bounding sequences I and II denotes both a climate change and tectonic rearrangement of the basin. This surface delineates a change in the depositional style, from fluvial-aeolian-lacustrine (Sequence I) to entirely fluvial (Sequence II). The latter includes coarse-grained to conglomeratic sandstone deposited within northwestward-flowing braided channel-belts. Changes in fluvial palaeocurrent, from sequence I to II, indicate rearrangement of the drainage system related to basin tectonism. Furthermore, a change in the fluvial discharge regime took place as a result of a change from a drier to a wetter climate. Fluvial deposition in Sequence I was related to ephemeral streams whereas fluvial facies architecture of the Sequence II deposits indicates perennial braided streams with significant discharge variation. Another regional unconformity, this time related to a stratigraphic base level fall and consequent widespread, basinwide aeolian deflation, separates the braided fluvial facies of Sequence II from the fine- to medium-grained sandstones ascribed to sheet-floods, aeolian dunes and aeolian sand sheets of Sequence III. The resumption of aeolian sedimentation indicates a return to drier conditions in the basin. The abrupt change from fluvial-aeolian deposits to the lacustrine deposits of the overlying Itaparica Formation suggest a rapid rise of the water table and consequent basinwide flooding.

  16. Undiscovered hydrocarbon resources in the U.S. Gulf Coast Jurassic Norphlet and Smackover Formations

    USGS Publications Warehouse

    Pearson, Ofori N.

    2011-01-01

    The U.S. Geological Survey has completed assessments of undiscovered technically recoverable oil and gas resources in the Jurassic Norphlet and Smackover formations of the onshore coastal plain and State waters of the U.S. Gulf Coast. The Norphlet Formation consists of sandstones and interbedded shales and siltstones deposited during a marine transgression. Along its northeast margin, deposition of the Norphlet was in alluvial fans, fluvial systems, and dune and clastic sabkha environments. Mudstones of the underlying Smackover Formation act as source rocks for Norphlet reservoirs. The Norphlet was divided into the following three assessment units (AUs): the Norphlet Salt Basins and Updip AU, the Norphlet Mobile Bay Deep Gas AU, and the Norphlet South Texas Gas AU. The lower part of the Smackover consists primarily of dark carbonate mudstone and argillaceous limestone deposited in low-energy environments, and is one of the Gulf of Mexico Basins major source rocks. The upper part of the Smackover is comprised primarily of grain-supported carbonates deposited in high-energy environments. The Smackover was divided into the following four AUs: the Smackover Updip and Peripheral Fault Zone AU, the Smackover Salt Basin AU, the Smackover South Texas AU, and the Smackover Downdip Continuous Gas AU. Although the Norphlet and Smackover formations have been the focus of extensive exploration and production, they probably still contain significant undiscovered oil and gas resources.

  17. Geologic study and engineering review of Jurassic Smackover Formation of Thomasville field, Rankin County, Mississippi

    SciTech Connect

    Shew, R.D.; Garner, M.M.

    1986-09-01

    The Jurassic (Oxfordian) Smackover Formation in Thomasville field, Rankin County, Mississippi, produces sour gas from deep (19,000 + ft), geopressured (> 0.88 psi/ft) siliciclastics that are interbedded with nonreservoir carbonates. The siliciclastics are moderately to moderately well-sorted, fine to medium-grained subarkosic sandstones. They are characterized by low average porosities (7.0%) and permeabilities (0.35 md) resulting from both diagenetic and primary textural controls. Secondary and altered primary porosity are present. Permeability is reduced by several diagenetic events, including the formation of anthraxolite and authigenic fibrous illite. Smackover carbonate ramp deposition was interrupted in Thomasville by the periodic influx of siliciclastics. Siliciclastics were delivered to the basin of deposition by ancestral drainage systems and distributed on the ramp by current and storm processes. They are interpreted to be shallow marine (beach and bar), inner shelf (sand waves and storm deposits), and outer shelf to upper basinal (storm and turbidite channels) deposits based on sedimentary structures, trace fossils, and lateral and vertical facies association with the interbedded carbonates. The carbonates indicate a shoaling-upward sequence, with outer shelf and upper basinal mudstones and wackestones at the base grading upward through shelf packstones, high-energy ooid grainstone shoals, and asphalt intertidal mudstones to grainstones. Rock properties and interpretations of the depositional environments were based on core and drill-cutting analyses. These analyses supplemented the use of computer-enhanced wireline logs to establish rock-log calibrations, correlation markers, structural growth, and reservoir continuity.

  18. Todilto Formation: a Jurassic salina and its petroleum potential in east-central New Mexico

    SciTech Connect

    Lucas, S.G.; Kietzke, K.K.

    1986-03-01

    Todilto Formation of northern New Mexico and southwestern Colorado was deposited during the Middle Jurassic (middle Callovian) by a landlocked, saline lake (salina) developed in the Entrada erg. Evaporative pumping drew marine water from the Curtis sea in eastern Utah, which percolated through porous Entrada dune sands into the salina basin. The Todilto salina deposited organic-rich limestone (source rock) within a porous eolian sandstone (reservoir rock). In the San Juan basin, organic-rich Todilto limestones are a primary source of Entrada oil. There, the Todilto Limestone is generally overlain by a thick, impermeable gypsum sequence that allows Todilto hydrocarbons to migrate only into the underlying Entrada. In east-central New Mexico, the Todilto limestones pinch out into the Entrada and are not overlain by gypsum. Therefore, Todilto hydrocarbons should migrate either into the main Entrada body below the Todilto or into the Exeter member of the Entrada above. The Todilto/Entrada in east-central New Mexico has generally been overlooked in oil exploration because of its limited outcrop area and because burial depths did not seem sufficient for hydrocarbon maturation. However, until the late Cenozoic, the Todilto probably was continuous from western Quay County to the Four Corners, and east-central New Mexico was covered by a thick sequence of Cretaceous marine rocks. Furthermore, migrating Todilto hydrocarbons need not be restricted to existing Todilto outcrops, but may be expected up Entrada paleodip wherever porosity and stratigraphic traps allow accumulation.

  19. Sedimentological evolution, diagenesis and hydrocarbon potentiality of late Jurassic carbonates, Eastern Region, Yemen Arab Republic

    SciTech Connect

    El-anbaawy, M.I.H.; Al-thour, K.A. )

    1989-01-01

    On the basis of the lateral and vertical distribution of the lithofacies identified within the Late Jurassic Amran sequence (Thoma Member) in Jabal Al-Balaq area, Marib, Y.A.R., three megafacies were recognized. Proceeding from the shore landwards they are: Ooid bank, including barriers such as reefs and carbonate sand shoals adjacent to the margin of a shallow platform having intertidal to subtidal agitated water, the bank being composed of skeletal packstone, oolitic grainstone and oncolitic packstone; Shelf lagoon, behind the shoal, characterized by less turbulent pelletoidal wackestone, sandy mudstone and algal stromatolite (boundstone); Alluvial coastal plain, including tidal sand flat of the marine shoreline-intertidal area, where cross-bedded sandstone and alluvial fan toe conglomerate were deposited. The apparent small-scale facies variations which are the result of the allocyclic tectonically controlled sea level fluctuations, reflect a complex interfingering of the depositional environments and the resulting rock types. The paragenetic sequence of the post-depositional processes within the siliciclastics inferred is: iron oxide cementation, authigenic growth of mica clays, generation of pressure solution and compaction, and generation of quartz overgrowths. It is indicated that the compaction process followed the neomorphism and cementation within the carbonates.

  20. A Giant Pliosaurid Skull from the Late Jurassic of England

    PubMed Central

    Benson, Roger B. J.; Evans, Mark; Smith, Adam S.; Sassoon, Judyth; Moore-Faye, Scott; Ketchum, Hilary F.; Forrest, Richard

    2013-01-01

    Pliosaurids were a long-lived and cosmopolitan group of marine predators that spanned 110 million years and occupied the upper tiers of marine ecosystems from the Middle Jurassic until the early Late Cretaceous. A well-preserved giant pliosaurid skull from the Late Jurassic Kimmeridge Clay Formation of Dorset, United Kingdom, represents a new species, Pliosaurus kevani. This specimen is described in detail, and the taxonomy and systematics of Late Jurassic pliosaurids is revised. We name two additional new species, Pliosaurus carpenteri and Pliosaurus westburyensis, based on previously described relatively complete, well-preserved remains. Most or all Late Jurassic pliosaurids represent a globally distributed monophyletic group (the genus Pliosaurus, excluding ‘Pliosaurus’ andrewsi). Despite its high species diversity, and geographically widespread, temporally extensive occurrence, Pliosaurus shows relatively less morphological and ecological variation than is seen in earlier, multi-genus pliosaurid assemblages such as that of the Middle Jurassic Oxford Clay Formation. It also shows less ecological variation than the pliosaurid-like Cretaceous clade Polycotylidae. Species of Pliosaurus had robust skulls, large body sizes (with skull lengths of 1.7–2.1 metres), and trihedral or subtrihedral teeth suggesting macropredaceous habits. Our data support a trend of decreasing length of the mandibular symphysis through Late Jurassic time, as previously suggested. This may be correlated with increasing adaptation to feeding on large prey. Maximum body size of pliosaurids increased from their first appearance in the Early Jurassic until the Early Cretaceous (skull lengths up to 2360 mm). However, some reduction occurred before their final extinction in the early Late Cretaceous (skull lengths up to 1750 mm). PMID:23741520

  1. Impact Crater Identified on the Navajo Nation Near Chinle, Arizona

    NASA Astrophysics Data System (ADS)

    Shoemaker, E. M.; Roddy, D. J.; Moore, C. B.; Pfeilsticker, R.; Curley, C. L.; Dunkelman, T.; Kuerzel, K.; Taylor, M.; Shoemaker, C.; Donnelly, P.

    1995-09-01

    A small impact crater has been identified about 8 km north of Chinle, Arizona on the Navajo Nation. Preliminary studies show that the crater is elongate in a N-S direction, measuring about 23 by 34 m in diameter, with a depth of about 1.3 m. The impact origin of the crater is identified by its shape, subsurface deformation, and an iron-nickel oxide fragment. We estimate the age to be about 150 to 250 years. The impact site is on the east side of the Chinle Valley at an altitude of 1685 m and is about 2 km east of Chinle Wash. The crater formed on an alluvial surface that slopes gently west toward the Wash. About 2 m of reddish brown alluvial sand and silt of the Jeddito Formation of late Pleistocene age rests on the Petrified Forest Member of the Chinle Formation of late Triassic age. A moderately developed late Pleistocene pedocal soil has developed on the Jeddito. Several thin discontinuous caliche horizons occur at a depth of about 1 m. The caliche horizons provided easily traced markers by which we could delimit the original walls of the crater and recognize deformation along the crater walls. Three trenches were excavated down to the top of the Chinle bedrock: 1) an east- west trench 31 m long across the center of the crater, 2) a north-south trench 13 m long in the north crater rim, and 3) a north-south trench 12 m long in the south crater rim. Excavation width was about 1 m and provided excellent exposures of the subsurface stratigraphy and deformation. The trenches revealed that the original crater was about 23 m wide and 27 m long. The original rim crests have entirely eroded away so that no perceptible raised rim remains. At the center of the crater, the original depth was about 3 m; material washed from the rims now fills the crater floor to a depth of 1.5 m. The crater is symmetrical; however, the deepest part of the original crater lies south of the center and was not reached in the south trench. The east-west trench showed that the initial floor of the crater was scoured down to the Jeddito-Chinle contact across the center of the crater. Some of the Chinle was excavated by impact south of the center, as seen in the trench in the south wall. The original crater walls slope inward about 30 degrees on the east and west sides, about 20 degrees on the north, and about 45 degrees on the south. Beds are dragged up along the east, west, and south walls, but not along the north wall. The deformation is restricted to within about 0.5 m of the wall. From the asymmetry of shape and deformation in the walls, we believe that the impacting body struck at an oblique angle and was traveling from north to south. A small, magnetic, iron oxide fragment, about 1 mm across, was collected from material excavated from the south crater wall area. Analyses of this fragment by electron microprobe detected a significant nickel concentration of 5%. Two senior Navajo women (70-80 year age range) independently remember this crater as being much deeper during their childhood and both suggest that the impact was witnessed 3 to 4 generations ago. Interestingly, many persons in the Navajo community thought that this crater was of impact origin. Additional work is planned, including a broader aerial search for other possible impact sites.

  2. The Navajos' Long Walk for Education (Dine Nizaagoo lina Bihooaah Yikanaaskai). A History of Navajo Education (Dine Ohoot aahii Baa Hane).

    ERIC Educational Resources Information Center

    Thompson, Hildegard

    Comprised of nine chapters, this book documents the educational history of the Navajo Nation. Written by one "who was there" as Director of Indian Education during the Truman, Eisenhower, Kennedy, and Johnson administrations, this book describes the labors of many, many American Indians and Anglos who worked together to bring about universal

  3. Evaluating Reading Materials in Navajo: Report of a Teachers' Conference (Gallup, New Mexico, April 28-29, 1972). Navajo Reading Study Progress Report No. 18.

    ERIC Educational Resources Information Center

    Gradman, Harry L.; Young, Robert W.

    Elementary-grade reading materials produced in the Navajo language were evaluated at a teacher's conference held in Gallup, New Mexico, on April 28-29, 1972. Participants, mostly teachers, at the conference numbered approximately 45. The 5 texts evaluated were "Mosilgai" (School Cat), "Jasper," Pabii Doo Masi" (Puppy and Cat), "Da'iida" (Eat), and…

  4. Fractures and stresses in Bone Spring sandstones

    SciTech Connect

    Warpinski, N.R.; Sattler, A.R.; Lorenz, J.C.; Northrop, D.A.

    1992-06-01

    This project was a collaboration between Sandia National Laboratories and the Harvey E. Yates Company (Heyco), Roswell, NM, conducted under the auspices of Department of Energy's Oil Recovery Technology Partnership. The project applied Sandia perspectives on the effects of natural fractures, stress, and sedimentology for the stimulation and production of low permeability gas reservoirs to low permeability oil reservoirs, such as those typified by the Bone Spring sandstones of the Delaware Basin, southeast New Mexico. This report details the results and analyses obtained in 1990 from core, logs, stress, and other data taken from three additional development wells. An overall summary gives results from all five wells studied in this project in 1989--1990. Most of the results presented are believed to be new information for the Bone Spring sandstones.

  5. Radionuclide transport in sandstones with WIPP brine

    SciTech Connect

    Weed, H.C.; Bazan, F.; Fontanilla, J.; Garrison, J.; Rego, J.; Winslow, A.M.

    1981-02-01

    Retardation factors (R) have been measured for the transport of /sup 3/H, /sup 95m/Tc, and /sup 85/Sr in WIPP brine using St. Peter, Berea, Kayenta, and San Felipe sandstone cores. If tritium is assumed to have R=1, /sup 95m/Tc has R=1.0 to 1.3 and therefore is essentially not retarded. Strontium-85 has R = 1.0 to 1.3 on St. Peter, Berea, and Kayenta, but R=3 on San Felipe. This is attributed to sorption on the matrix material of San Felipe, which has 45 volume % matrix compared with 1 to 10 volume % for the others. Retardation factors (R/sub s/) for /sup 85/Sr calculated from static sorption measurements are unity for all the sandstones. Therefore, the static and transport results for /sup 85/Sr disagree in the case of San Felipe, but agree for St. Peter, Berea, and Kayenta.

  6. True triaxial testing of Castlegate sandstone.

    SciTech Connect

    Ingraham, M. D.; Holcomb, David Joseph; Issen, Kathleen A.

    2010-03-01

    Deformation bands in high porosity sandstone are an important geological feature for geologists and petroleum engineers; however, their formation is not fully understood. Axisymmetric compression, the common test for this material, is not sufficient to fully evaluate localization criteria. This study seeks to investigate the influence of the second principal stress on the failure and the formation of deformation bands in Castlegate sandstone. Experimental results from tests run in the axisymmetric compression stress state, as well as a stress state between axisymmetric compression and pure shear will be presented. Samples are tested using a custom triaxial testing rig at Sandia National Laboratories capable of applying stresses up to 400 MPa. Acoustic emissions are used to locate deformation bands should they not be visible on the specimen exterior. It is suspected that the second invariant of stress has a strong contribution to the failure mode and band formation. These results could have significant bearing on petroleum extraction as well as carbon dioxide sequestration.

  7. Synkinematic quartz cementation in partially open fractures in sandstones

    NASA Astrophysics Data System (ADS)

    Ukar, Estibalitz; Laubach, Stephen E.; Fall, Andras; Eichhubl, Peter

    2014-05-01

    Faults and networks of naturally open fractures can provide open conduits for fluid flow, and may play a significant role in hydrocarbon recovery, hydrogeology, and CO2 sequestration. However, sandstone fracture systems are commonly infilled, at least to some degree, by quartz cement, which can stiffen and occlude fractures. Such cement deposits can systematically reduce the overall permeability enhancement due to open fractures (by reducing open fracture length) and result in permeability anisotropies. Thus, it is important to identify the factors that control the precipitation of quartz in fractures in order to identify potential fluid conduits under the present-day stress field. In many sandstones, quartz nucleates syntaxially on quartz grain or cement substrate of the fracture wall, and extends between fracture walls only locally, forming pillars or bridges. Scanning electron microscope cathodoluminescence (SEM-CL) images reveal that the core of these bridges are made up of bands of broken and resealed cement containing wall-parallel fluid inclusion planes. The fluid inclusion-rich core is usually surrounded by a layer of inclusion-poor clear quartz that comprises the lateral cement. Such crack-seal textures indicate that this phase was precipitating while the fractures were actively opening (synkinematic growth). Rapid quartz accumulation is generally believed to require temperatures of 80C or more. Fluid inclusion thermometry and Raman spectroscopy of two-phase aqueous fluid-inclusions trapped in crack-seal bands may be used to track the P-T-X evolution of pore fluids during fracture opening and crack-seal cementation of quartz. Quartz cement bridges across opening mode fractures in the Cretaceous Travis Peak Formation of the tectonically quiescent East Texas Basin indicate individual fractures opened over a 48 m.y. time span at rates of 16-23 m/m.y. Similarly, the Upper Cretaceous Mesaverde Group in the Piceance Basin, Colorado contains fractures that have recorded opening histories that lasted several tens of millions of years. Quartz bridges will form when the increase in fracture aperture is small for single fracture events, the rate of precipitation is greater than the rate of fracture aperture, and fresh non-euhedral nucleation surfaces continue to be created by fracturing. Because of the vast difference in growth rates between the c-axis (fast) and the a-axis (slow) of quartz crystals, the crystallographic orientation of quartz may play a role on the morphology and size of such bridges, and therefore degree of cement infill in fractures. SEM-based backscattered electron diffraction (EBSD) was used to explore the effect of the crystallographic orientation of quartz on the growth of quartz bridges in fractures from the Jurassic-Cretaceous Nikanassin Formation, northwestern Alberta Foothills, the Travis Peak Formation, East Texas, and the Cretaceous Mesaverde Group, Piceance Basin, Colorado. We find that, in all samples, most c-axes are oblique rather than perpendicular to the fracture wall, and well-developed bridges that are oriented at a low angle to the fracture wall are widespread. We conclude that precipitation on anhedral (fractured) surfaces exerts a larger control on the growth of quartz bridges than the orientation of the crystallographic c-axis.

  8. Early Jurassic black shales: Global anoxia or regional "Dead Zones"?

    NASA Astrophysics Data System (ADS)

    van de Schootbrugge, B.; Payne, J.; Wignall, P.

    2012-12-01

    The so-called "Schwarzer Jura" or "Black Jurassic" in Germany is informally used to designate a series of organic-rich sediments that roughly span the Early Jurassic (201.6 - 175.6 Myr), and which culminate in the Toarcian Oceanic Anoxic Event. Based on organic and inorganic geochemical as well as (micro)palaeontological data from several recently drilled cores, black shales deposited directly following the end-Triassic extinction (201.6 Ma) during the Hettangian are extremely similar to Toarcian black shales. Both events are characterized by laminated black shales that contain high amounts of the biomarker isorenieratane, a fossilized pigment derived from green sulphur bacteria. Furthermore, the two intervals show similar changes in phytoplankton assemblages from chromophyte (red) to chlorophyte (green) algae. Combined, the evidence suggests that photic zone euxinia developed repeatedly during the Early Jurassic, making wide swaths of shelf area inhospitable to benthic life. In the oceans today such areas are called "Dead Zones" and they are increasing in number and extent due to the combined effects of man-made eutrophication and global warming. During the Early Jurassic, regional anoxic events developed in response to flood basalt volcanism, which triggered global warming, increased run-off, and changes in ocean circulation. The patchiness of Early Jurassic anoxia allows comparisons to be made with present-day "Dead Zones", while at the same time ocean de-oxygenation in the past may serve to predict future perturbations in the Earth system.

  9. The Triassic-Jurassic boundary in eastern North America

    NASA Technical Reports Server (NTRS)

    Olsen, P. E.; Comet, B.

    1988-01-01

    Rift basins of the Atlantic passive margin in eastern North America are filled with thousands of meters of continental rocks termed the Newark Supergroup which provide an unprecedented opportunity to examine the fine scale structure of the Triassic-Jurassic mass extinction in continental environments. Time control, vital to the understanding of the mechanisms behind mass extinctions, is provided by lake-level cycles apparently controlled by orbitally induced climate change allowing resolution at the less than 21,000 year level. Correlation with other provinces is provided by a developing high resolution magnetostratigraphy and palynologically-based biostratigraphy. A large number of at least local vertebrate and palynomorph extinctions are concentrated around the boundary with survivors constituting the earliest Jurassic assemblages, apparently without the introduction of new taxa. The palynofloral transition is marked by the dramatic elimination of a relatively high diversity Triassic pollen assemblage with the survivors making up a Jurassic assemblage of very low diversity overwhelmingly dominated by Corollina. Based principally on palynological correlations, the hypothesis that these continental taxonomic transitions were synchronous with the massive Triassic-Jurassic marine extinctions is strongly corroborated. An extremely rapid, perhaps catastrophic, taxonomic turnover at the Triassic-Jurassic boundary, synchronous in continental and marine realms is hypothesized and discussed.

  10. Supraregional seismites in Triassic - Jurassic boundary strata

    NASA Astrophysics Data System (ADS)

    Lindström, Sofie; Pedersen, Gunver K.; van de Schootbrugge, Bas; Johansson, Leif; Petersen, Henrik I.; Dybkjær, Karen; Weibel, Rikke; Hansen, Katrine H.; Erlström, Mikael; Alwmark, Carl; Nielsen, Lars Henrik; Oschmann, Wolfgang; Tegner, Christian

    2014-05-01

    The end-Triassic mass extinction event (201.564 Ma) was synchronous with the earliest volcanic phase during the emplacement of the Central Atlantic Magmatic Province (CAMP), a large igneous province (LIP) formed during the initial breakup of Pangea. Volcanic degassing of CO2 and other volatile gases, and/or thermogenic methane, from the CAMP is generally regarded as the main cause of the end-Triassic biotic crisis. However, discrepancies in the durations of the ETE (50 Kyrs) and the CAMP volcanism (600 Kyrs) as well as temporal offsets between carbon cycle perturbations and biotic turnovers suggest a more complex scenario that require further studies of the temporal succession of events in Triassic-Jurassic (TJ) boundary strata. Here, we present and examine multiple episodes of soft-sediment deformation (seismite) within uppermost Rhaetian marine and terrestrial strata of Denmark, Sweden and Germany. These seismites are stratigraphically constrained by palynology and C-isotopes to the latest Rhaetian, and are synchronous to the single seismite layer from the UK, which similarly predates the T/J boundary, and has been explained by an extraterrestrial bolide impact. Instead, we argue that the multiple episodes of soft-sediment deformation, interbedded by undisturbed strata, were formed from repeated intense earthquake activity restricted to an interval within the latest Rhaetian bracketed by two negative excursions in δ13C and also containing palynological evidence for deforestation and fern proliferation. The fact that these biotic changes coincide with repeated seismic activity has implications for the end-Triassic extinction and the CAMP scenario. We discuss the temporal position of the seismites in regards to other end-Triassic events, and argue that their supraregional distribution in pre-TJ-boundary strata of NW Europe may be linked to intensified earthquake activity during CAMP emplacement, rather than an extraterrestrial impact.

  11. Matrix versus fracture permeability in a regional sandstone aquifer (Wajid sandstone, SW Saudi Arabia)

    NASA Astrophysics Data System (ADS)

    Al Ajmi, Hussain; Hinderer, Matthias; Rausch, Randolf; Hornung, Jens; Bassis, Alexander; Keller, Martin; Schth, Christoph

    2014-06-01

    Sandstones are often characterized as fractured aquifers. We present a case study of the Wajid sandstone, which forms a regional aquifer system in SW Saudi Arabia, where matrix, fracture, and large-scale hydraulic conductivities are coincident. The measurements deal with different scales and methods and are based on porosity and permeability measurements in the laboratory, as well as pumping tests in the field. Porosities of the sandstone samples in general are high and range between less than 5 % and more than 45 %. Gas permeabilities for strongly cemented samples are < 1 mD, whereas most samples range in between 500 and 5,000 mD. There is only a weak anisotropy with preference of the horizontal x-, y-directions. Hydraulic conductivities of the matrix samples (5.5 10-6 m/s and 1.1 10-5 m/s for the Upper and Lower Wajid sandstone, respectively) were in the same order of magnitude compared to hydraulic conductivities derived from pumping tests (8.3 10-5 m/s and 2.2 10-5 m/s for the Upper and Lower Wajid sandstone, respectively).

  12. A Feasibility Study to Evaluate Wind Energy Potential on the Navajo Nation

    SciTech Connect

    Terry Battiest

    2012-11-30

    The project, A Feasibility Study to Evaluate Wind Energy Potential on the Navajo Nation, is funded under a solicitation issued by the U.S. Department of Energy Tribal Energy Program. Funding provided by the grant allowed the Navajo Nation to measure wind potential at two sites, one located within the boundaries of the Navajo Nation and the other off-reservation during the project period (September 5, 2005 - September 30, 2009). The recipient for the grant award is the Navajo Tribal Utility Authority (NTUA). The grant allowed the Navajo Nation and NTUA manage the wind feasibility from initial site selection through the decision-making process to commit to a site for wind generation development. The grant activities help to develop human capacity at NTUA and help NTUA to engage in renewable energy generation activities, including not only wind but also solar and biomass. The final report also includes information about development activities regarding the sited included in the grant-funded feasibility study.

  13. Petrographic and geochemical characterization of the Triassic and Jurassic magmatic and volcanic rocks of southeastern Ecuador

    NASA Astrophysics Data System (ADS)

    Villares, Fabián; Eguez, Arturo; Yanez, Ernesto

    2014-05-01

    Formely, the subandean zone in the southeastern Ecuador involved large volcanic and magmatic rocks included in the Misahualli Formation and Zamora batholith, both as expression of the Jurassic cal-alcaline volcanic arc. The aim of the project carried out by the INIGEMM (Instituto Nacional de Investigación Geológico Minero Metalúrgico) was discriminate the volcanic products including a continuous set going from basalts to ryolithes and volcanoclastic rocks. Geochemical characterization was done using representative 16 whole - rock chemical analysis. The oldest rocks of the investigated area called Pachicutza Unit, include greenish to black, massive basalts and basaltic andesites, locally showing pillows structures. The texture is aphanitic to microporphyritic with slight crystal growth of plagioclase and pyroxenes. The Unit include also local pyroclastic breccias and tuffs showing variable skarnification related to the intrusion of the jurassic Zamora Batholith. Two samples of basalts show tholeiitic affinity, corresponding to an N- MORB, probably representing an early stage in opening of a regional Triassic rift reported since Colombia to Peru in the Andes. These geochemical characteristics are similar to the amphibolites of Monte Olivo Unit in the Real Cordillera. The Jurassic large volcanic assembly of the Misahualli Formation was also differenciated. Basal volcanics include green, subporphyritic andesites and volcanic breccias possibly generated at an early stage of the volcanic arc, caused by a change of extensive to compressive regime. Continental volcano sedimentary and sedimentary rock were discriminate as Nueva Esperanza and Suarez Units, respectively. The volcanosedimentary sequence include massive to laminate tuffs and tuffites of intermediate composition. The sediments of the Suarez Unit include dominant conglomerats and sandstones of fluvial domain. The regional volcanic sequence is completed by the Las Peñas Unit that includes aphanitic to porphyritic andesites and coarse volcanic breccias. Three geochemical analysis of the lavas show andesitic composition, have medium to high-K calc-alkaline and represent the products of a subduction zone. All intrusions in the area were mapped as Zamora Batholith. Nevetheless, the field observations confirm a large Jurassic batholith but also other significant minor intrusion that intrudes the cretaceous sedimentary formations of the area. Thus, magmatic rocks in the area are named as Zamora batholithic complex. Petrography of the Zamora Batholith ranges from tonalite to monzo-granite with the same qualitative mineralogy. Rocks are composed by different proportions of plagioclase, amphibole, K-feldspar, quartz, biotite, opaques and epidote, as accessory minerals has zircon, sphene and apatite. Zamora Granitoids ranged from dioritic to granitic compositions ( 60.09 - . 73.6 wt % SiO2). The Zamora Granitoids have medium to high-K calc-alkaline and represent the products of a subduction zone. Products are generated within a magmatic arc in normal conditions of maturity. The Zamora Granitoids are I - type intrusions.

  14. Navajo birth outcomes in the Shiprock uranium mining area

    SciTech Connect

    Shields, L.M.; Wiese, W.H.; Skipper, B.J.; Charley, B.; Benally, L. )

    1992-11-01

    The role of environmental radiation in the etiology of birth defects, stillbirths, and other adverse outcomes of pregnancy was evaluated for 13,329 Navajos born at the Public Health Service/Indian Health Service Hospital in the Shiprock, NM, uranium mining area (1964-1981). More than 320 kinds of defective congenital conditions were abstracted from hospital records. Using a nested case-control design, families of 266 pairs of index and control births were interviewed. The only statistically significant association between uranium operations and unfavorable birth outcome was identified with the mother living near tailings or mine dumps. Among the fathers who worked in the mines, those of the index cases had histories of more years of work exposure but not necessarily greater gonadal dosage of radiation. Also, birth defects increased significantly when either parent worked in the Shiprock electronics assembly plant. Overall, the associations between adverse pregnancy outcome and exposure to radiation were weak and must be interpreted with caution with respect to implying a biogenetic basis.

  15. Effects of Coupled Structural and Diagenetic Processes on Deformation Localization and Fluid Flow Properties in Sandstone Reservoirs of the Southwestern United States

    NASA Astrophysics Data System (ADS)

    Elliott, S. J.; Eichhubl, P.; Landry, C. J.

    2014-12-01

    Fluid flow tends to be restricted perpendicular to deformation bands through the combined effects of mechanical grain size reduction, porosity loss, and preferred cementation relative to the adjacent host rock. Deformation bands that occur in association with reservoir scale faults can impact reservoir-scale fluid flow and fault seal behavior, potentially imparting a permeability anisotropy to reservoir rocks. We use a combination of Hg-intrusion porosimetry, high-resolution 2D-image analysis of pore size distributions, and detailed compositional analyses obtained from integrating petrographic and SEM-based imaging techniques, including SEM-cathodoluminescence, backscattered electron imaging, and energy-dispersive X-ray spectroscopy, to (1) assess the effects of coupled chemical and mechanical processes leading to deformation localization within various detrital compositions [Cedar Mesa, Navajo, and Entrada sandstones] and (2) to quantify the effect of these processes on single and multiphase fluid flow as a function of host rock properties, structural position, and deformation band textural and diagenetic properties. Within each sample, bands of differing kinematic properties and structural style, i.e. shear bands, shear enhanced compaction bands etc., were identified and pre-kinematic pore-filling cements, as well as syn- and post-kinematic cements including various clay minerals, were distinguished for both the host rock and associated deformation bands. Although the deformation bands display a variety of textures and diagenetic attributes, initial petrophysical results suggest that the flow properties - permeability and capillary pressure curves - of the bands in the formations studied are very similar. However, both individual and clustered deformation bands of the Navajo Sandstone contain open or partially cemented cross-cutting fractures that could act as flow pathways across the deformation bands.

  16. Petrographic and geochemical constraints on the formation and diagenesis of anhydrite cements, Smackover sandstones, Gulf of Mexico

    SciTech Connect

    Dworkin, S.I. . Dept. of Geology); Land, L.S. . Dept. of Geological Sciences)

    1994-04-01

    Anhydrite cement is common in sedimentary rocks, yet its origin is poorly understood. The high concentration of sulfate in sea water and the lack of appreciable sulfate in most other natural waters suggests that anhydrite cement may have a marine origin, but the relatively late timing of most anhydrite cement tends to preclude sea water as the source of sulfate. Anhydrite cement is present in Upper Jurassic sandstones in the Gulf of Mexico as poikilotopic masses in which detrital grains are replaced and as smaller patches that have replaced single detrital grains. Anhydrite is a relatively late cement and postdates all other volumetrically significant authigenic phases, including K-feldspar, dolomite, quartz, and most calcite cements. The expected isotopic composition and trace-element concentration of marine-derived Late Jurassic anhydrite cement is predicted based on analyses of bedded anhydrite and on analyses found in literature. The expected chemical signature is: [delta][sup 34]S ([per thousand]CDT) = +16, [delta][sup 18]O ([per thousand]SMOW) = +14, [sup 87]Sr/[sup 86]Sr = 0.7069, Sr = 1500--2500 ppm, Ba < 20 ppm, and Mg > 200 ppm. When geochemical analyses of Smackover anhydrite cements are compared to the predicted composition, it is apparent that most of the cement is not of marine origin. The chemistry of Louisiana and Mississippi basin anhydrite cements indicates that the sulfate was derived from dissolved bedded anhydrite and was reprecipitated in the sandstones from fluids that had undergone extensive water-rock interaction after considerable burial. This study suggests that late anhydrite cements in sedimentary rocks are most likely derived from remobilized calcium sulfate deposits.

  17. "Enemies Like a Road Covered with Ice": The Utah Navajos' Experience during the Long Walk Period, 1858-1868

    ERIC Educational Resources Information Center

    Hornsby, Sarah; McPherson, Robert S.

    2009-01-01

    Much has been written of the Navajo Long Walk period when the Navajo people, following what appears to be a fairly short resistance, surrendered in droves to the US military, collected at Fort Defiance and other designated sites, then moved in a series of "long walks" to Fort Sumner (Hweeldi) on the Pecos River in eastern New Mexico. There was

  18. The Role of Education in American Indian Self-Determination: Lessons from the Ramah Navajo Community School

    ERIC Educational Resources Information Center

    Manuelito, Kathryn

    2005-01-01

    Since 1975 the Indian Self-Determination and Educational Assistance Act has enabled American Indian communities to enact self-determination through community-based schooling. In this study conducted by a Navajo researcher, the Ramah Navajo community defined self-determination and how it was operationalized within the community and school. The

  19. Concurrent and Longitudinal Effects of Ethnic Identity and Experiences of Discrimination on Psychosocial Adjustment of Navajo Adolescents

    ERIC Educational Resources Information Center

    Galliher, Renee V.; Jones, Matthew D.; Dahl, Angie

    2011-01-01

    In this study, we examined concurrent and longitudinal relations among Navajo adolescents' ethnic identity, experiences of discrimination, and psychosocial outcomes (i.e., self-esteem, substance use, and social functioning). At Time 1, 137 Navajo adolescents (67 male, 70 female), primarily in Grades 9 and 10, completed a written survey assessing

  20. The Role of Education in American Indian Self-Determination: Lessons from the Ramah Navajo Community School

    ERIC Educational Resources Information Center

    Manuelito, Kathryn

    2005-01-01

    Since 1975 the Indian Self-Determination and Educational Assistance Act has enabled American Indian communities to enact self-determination through community-based schooling. In this study conducted by a Navajo researcher, the Ramah Navajo community defined self-determination and how it was operationalized within the community and school. The…

  1. 78 FR 2685 - Notice of Intent To Prepare a Programmatic Environmental Impact Statement (EIS) for the Navajo...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-14

    ...) for the Navajo Nation Integrated Weed Management Plan Within Coconino, Navajo, and Apache Counties... Department of Transportation serving as cooperating agencies, intends to prepare an EIS for a proposed weed... . SUPPLEMENTARY INFORMATION: The BIA is proposing to develop a ten-year integrated weed management plan for...

  2. Harvestmen (Arachnida: Opiliones) from the Middle Jurassic of China

    NASA Astrophysics Data System (ADS)

    Huang, Diying; Selden, Paul A.; Dunlop, Jason A.

    2009-08-01

    Harvestmen (Arachnida: Opiliones) are familiar animals in most terrestrial habitats but are rare as fossils, with only a handful of species known from each of the Palaeozoic, Mesozoic, and Cenozoic eras. Fossil harvestmen from Middle Jurassic (ca. 165 Ma) strata of Daohugou, Inner Mongolia, China, are described as Mesobunus martensi gen. et sp. nov. and Daohugopilio sheari gen. et sp. nov.; the two genera differ primarily in the relative length of their legs and details of the pedipalps. Jurassic arachnids are extremely rare and these fossils represent the first Jurassic, and only the fourth Mesozoic, record of Opiliones. These remarkably well-preserved and modern-looking fossils are assigned to the Eupnoi, whereby M. martensi demonstrably belongs in Sclerosomatidae. It thus represents the oldest record of a modern harvestman family and implies a high degree of evolutionary stasis among one of the most widespread and abundant groups of long-legged, round-bodied harvestmen.

  3. Constraints on Upper Jurassic palaeogeography in the Ula Gyda trend

    SciTech Connect

    Mundal, I.; Milton, N.; Robinson, N.

    1995-08-01

    BP Norway`s semi-regional 3D database in the Central Trough covers an area of nearly 3000 sq.km. around BP Norway`s two producing fields, Ula and Gyda, and includes strategic acreage within tie-back distance to the fields. Prospectivity in the Ula Gyda trend involves complex salt influenced structures and localized Upper Jurassic depositional systems. The objective of this paper is to demonstrate how the understanding of the semi-regional structures and salt tectonics helped constrain the interpretation of the Upper Jurassic palaeogeography. The control of basement structures (Permian) on cover structures (Upper Jurassic/Base Cretaceous) through Zechstein Salt was interpreted using the 3D semi-regional dataset. Analogue sandbox experiments from the Austin Geodynamics Laboratory provide support for the complex structures which were interpreted on the 3D seismic data. Sandbox models mimic the interpreted monoclinal drape of the Triassic and Jurassic section over the critical basin bounding fault in the Base Zechstein. Structural cells can be identified with the help of the salt isochore. The understanding of the relationship between structural development and salt distribution was a major control on the interpretation. This interpretation coupled with the Upper Jurassic reservoir distribution from well data provided the primary evidence for the gross depositional environment maps which were used in prospect evaluation in the area. 3D visualization and shaded relief displays of the interpreted horizons and isochores played a significant part in developing an understanding of the interplay between the deeper structures and the likely Upper Jurassic palaeogeography and depocentres.

  4. Jurassic faults of southwest Alabama and offshore areas

    SciTech Connect

    Mink, R.M.; Tew, B.H.; Bearden, B.L.; Mancini, E.A. )

    1991-03-01

    Four fault groups affecting Jurassic strata occur in the southwest and offshore Alabama areas. They include the regional basement rift trend, the regional peripheral fault trend, the Mobile graben fault system, and the Lower Mobile Bay fault system. The regional basement system rift and regional peripheral fault trends are distinct and rim the inner margin of the eastern Gulf Coastal Plain. The regional basement rift trend is genetically related to the breakup of Pangea and the opening of the Gulf of Mexico in the Late Triassic-Early Jurassic. This fault trend is thought to have formed contemporaneously with deposition of Late Triassic-Early Jurassic Eagle Mills Formation and to displace pre-Mesozoic rocks. The regional peripheral fault trend consists of a group of en echelon extensional faults that are parallel or subparallel to regional strike of Gulf Coastal Plain strata and correspond to the approximate updip limit of thick Louann Salt. Nondiapiric salt features are associated with the trend and maximum structural development is exhibited in the Haynesville-Smackover section. No hydrocarbon accumulations have been documented in the pre-Jurassic strata of southwest and offshore Alabama. Productive hydrocarbon reservoirs occur in Jurassic strata along the trends of the fault groups, suggesting a significant relationship between structural development in the Jurassic and hydrocarbon accumulation. Hydrocarbon traps are generally structural or contain a major structural component and include salt anticlines, faulted salt anticlines, and extensional fault traps. All of the major hydrocarbon accumulations are associated with movement of the Louann Salt along the regional peripheral fault trend, the Mobile graben fault system, or the Lower Mobile Bay fault system.

  5. The second Jurassic dinosaur rush and the dawn of dinomania.

    PubMed

    Brinkman, Paul D

    2010-09-01

    During the second Jurassic dinosaur rush museum paleontologists raced to display the world's first mounted sauropod dinosaur. The American Museum of Natural History triumphed in 1905 when its Brontosaurus debuted before an admiring crowd of wealthy New Yorkers. The Carnegie Museum of Natural History in Pittsburgh, the Field Columbian Museum in Chicago and other institutions were quick to follow with their own sauropod displays. Thereafter, dinomania spread far and wide, and big, showpiece dinosaurs became a museum staple. This brief but intensely competitive period of acquisitiveness fostered important Jurassic dinosaur revisions and crucial innovations in paleontological field and lab techniques. PMID:20667597

  6. NASA and the Navajo Nation: A Collaborative Partnership Bringing Science and Cultural Knowledge Together

    NASA Astrophysics Data System (ADS)

    Carron, A.; Scalice, D.

    2010-12-01

    The NASA and the Navajo Nation project series began in 2005 with a question: are you, the Navajo education community, interested in partnering with NASA on educational initiatives? The answer was yes, and guidelines and priorities were put forward. We were very clear from the start that this effort was being enacted for the benefit of Navajo students and teachers, and may not be transferrable or applicable or scalable to other communities. Six years later, we are finalizing our second set of classroom materials and hosting teacher workshops. These materials bring together science and cultural knowledge in a dual-learning environment in which each 'way of knowing' is allowed to co-exist and interact, and a learner-centered environment wherein the ways in which they interact are not prescribed.

  7. Geological model of the Jurassic section in the State of Kuwait

    SciTech Connect

    Yousif, S.; Nouman, G.

    1995-11-01

    Until the end of the seventies, the knowledge of Jurassic Geology in the State of Kuwait was very limited, since only one deep well was drilled and bottomed in the Triassic sediments. Few scattered wells partially penetrated the Jurassic sequence. During the eighties, appreciable number of wells were drilled through the Jurassic, and added a remarkable volume of information. consequently it was necessary to analyze the new data, in order to try to construct a geological model for the Jurassic in the State of Kuwait. This paper includes a number of isopach maps explaining the Jurassic depositional basin which also helps in trying to explain the Jurassic basin in the Arabian Gulf basin. Structural evolution of the Jurassic sequence indicated an inversion of relief when compared with the Cretaceous sequence. In fact, the main Cretaceous arches were sites of sedimentation troughs during the Jurassic period. This fact marks a revolution in the concepts for the Jurassic oil exploration. One of the very effective methods of the definition of the Jurassic structures is the isopaching of the Gotnia Formation. Najmah, Sargelu and Marrat Formations include the main Jurassic reservoirs which were detected as a result of the exploration activities during the eighties. Selective stratigraphic and structural cross sections have been prepared to demonstrate and explain the nature of the Jurassic sediments.

  8. Assessments of aquifer sensitivity on Navajo Nation and adjacent lands and ground-water vulnerability to pesticide contamination on the Navajo Indian Irrigation Project, Arizona, New Mexico, and Utah

    USGS Publications Warehouse

    Blanchard, Paul J.

    2002-01-01

    The U.S. Environmental Protection Agency requested that the Navajo Nation conduct an assessment of aquifer sensitivity on Navajo Nation lands and an assessment of ground-water vulnerability to pesticide contamination on the Navajo Indian Irrigation Project. Navajo Nation lands include about 17,000 square miles in northeastern Arizona, northwestern New Mexico, and southeastern Utah. The Navajo Indian Irrigation Project in northwestern New Mexico is the largest area of agriculture on the Navajo Nation. The Navajo Indian Irrigation Project began operation in 1976; presently (2001) about 62,000 acres are available for irrigated agriculture. Numerous pesticides have been used on the Navajo Indian Irrigation Project during its operation. Aquifer sensitivity is defined by the U.S. Environmental Protection Agency as 'The relative ease with which a contaminant [pesticide] applied on or near a land surface can migrate to the aquifer of interest. Aquifer sensitivity is a function of the intrinsic characteristics of the geologic material in question, any underlying saturated materials, and the overlying unsaturated zone. Sensitivity is not dependent on agronomic practices or pesticide characteristics.' Ground-water vulnerability is defined by the U.S. Environmental Protection Agency as 'The relative ease with which a contaminant [pesticide] applied on or near a land surface can migrate to the aquifer of interest under a given set of agronomic management practices, pesticide characteristics, and aquifer sensitivity conditions.' The results of the aquifer sensitivity assessment on Navajo Nation and adjacent lands indicated relative sensitivity within the boundaries of the study area. About 22 percent of the study area was not an area of recharge to bedrock aquifers or an area of unconsolidated deposits and was thus assessed to have an insignificant potential for contamination. About 72 percent of the Navajo Nation study area was assessed to be in the categories of most potential or intermediate potential for contamination. About 6 percent of the study area was assessed to have the least potential for contamination, mostly in areas where the slope of the land surface is more than 12 percent. Nearly all fields on the Navajo Indian Irrigation Project were assessed to have the most potential for contamination. The assessment of ground-water vulnerability to pesticide contamination on the Navajo Indian Irrigation Project was based on pesticide application to various crops on part of the Navajo Indian Irrigation Project during 1997-99. The assessment indicated that ground water underlying fields of beans, wheat, barley, and alfalfa was most vulnerable to pesticide contamination; ground water underlying fields of corn and potatoes was intermediately vulnerable to pesticide contamination; and ground water underlying fields of hay was least vulnerable to pesticide contamination.

  9. Influence de la diagenèse d'enfouissement sur l'homogénéisation isotopique K-Ar des illites: exemple du Jurassique-Crétacé du bassin d'Agadir, MarocInfluence of burial diagenesis on K-Ar isotopic homogenisation of illites: example from Jurassic-Cretaceous sediments in the Agadir Basin, Morocco

    NASA Astrophysics Data System (ADS)

    Daoudi, L.; Portugal-Ferreira, M.; Igmoullan, B.

    2001-05-01

    The clay assemblages of the Late Jurassic-Early Cretaceous sediments of the Agadir Basin are affected by burial diagenesis. Apparent ages of these formations, from the K-Ar dating of fine grain size fractions (< 2 μm), decrease downward. This indicates an opening of the K-Ar isotopic system of detrital Hercynian minerals during burial. The extent of the isotopic rehomogenisation is more important in sandstones than in clayey marl facies. During burial diagenesis, a temperature of 165°C in clayey marl and 110°C in sandstone can be enough for isotopic rehomogenisation of fine-grained Hercynian illite. The migration of pore water seems to favour the diffusion of radiogenic 40Ar in sandstones.

  10. 57 Fe Mssbauer and X-ray characterisation of sandstones

    NASA Astrophysics Data System (ADS)

    Mulaba-Bafubiandi, A. F.; Waanders, F. B.

    2013-04-01

    Sandstones from the Free State province in South Africa have been mined and processed mainly by small scale and artisanal miners in the rural areas. In the present investigation basic fire proof and water absorption tests, X-ray and ?-ray based characterisation techniques were used to study the sandstones. The collected samples were grouped according to their apparent colour in day light conditions and the elemental analysis showed the presence of a high amount of oxygen (>52%) and silicon (>38%) with Mn, Al, Fe and Ca as major elements in proportions related to the colour distribution of the various sandstones. The uniaxial compressive stress was found to be the highest (56 MPa) for the greyish sandstone and the lowest (8 MPa) for the white sandstone sample, also associated with the lowest (Al+Fe)/Si value of 0.082. The humidity test showed that the 6 % water absorption was lower than the recommended ASTM value of 8 %. The sandstone samples were also subjected to various high temperatures to simulate possible fire conditions and it was found that the non alteration of the mineral species might be one of the reasons why the sandstones are regarded as the most refractory amongst the building materials typically used. Mssbauer spectroscopy revealed that iron is present in all the sandstones, mainly as Fe3 + with the black sandstone showing an additional presence of 3 % Fe2 + indicating that a higher iron content coupled to higher silicon content, contributes to an increase in the uniaxial compressive strength.

  11. Seawater can damage Saudi sandstone oil reservoirs

    SciTech Connect

    Dahab, A.S. )

    1990-12-10

    Experiments have shown that formation damage from waterflooding of the Aramco and Alkhafji sandstones of Saudi Arabia will not occur if the salinity of the injected brines is higher than 20% NaCl. Because the connate water in these reservoirs has a high salt content of up to 231,000 ppm, Saudi oil fields are almost always susceptible to formation damage when flooded with seawater (about 38,500 ppm). The productive behavior of a reservoir can be affected by clay crystals developed within rock pores.

  12. Apatite Fission-Track Analysis of the Middle Jurassic Todos Santos Formation from Chiapas, Mexico.

    NASA Astrophysics Data System (ADS)

    Abdullin, Fanis; Solé, Jesús; Shchepetilnikova, Valentina; Solari, Luigi; Ortega-Obregón, Carlos

    2014-05-01

    The Sierra de Chiapas (SCH), located in the south of Mexico, is a complex geological province that can be divided on four different lithological or tectonic areas: (1) the Chiapas Massif Complex (CMC); (2) the Central Depression; (3) the Strike-slip Fault Province, and (4) the Chiapas Fold-and-thrust Belt. The CMC mostly consists of Permian granitoids and meta-granitoids, and represents the basement of the SCH. During the Jurassic period red beds and salt were deposited on this territory, related to the main pulse of rifting and opening of the Gulf of Mexico. Most of the Cretaceous stratigraphy contains limestones and dolomites deposited on a marine platform setting during the postrift stage of the Gulf of Mexico rift. During the Cenozoic Era took place the major clastic sedimentation along the SCH. According the published low-temperature geochronology data (Witt et al., 2012), SCH has three main phases of thermo-tectonic history: (1) slow exhumation between 35 and 25 Ma, that affected mainly the basement (CMC) and is probably related to the migration of the Chortís block; (2) fast exhumation during the Middle-Late Miocene caused by strike-slip deformation that affects almost all Chiapas territory; (3) period of rapid cooling from 6 to 5 Ma, that affects the Chiapas Fold-and-thrust Belt, coincident with the landward migration of the Caribbean-North America plate boundaries. The two last events were the most significant on the formation of the present-day topography of the SCH. However, the stratigraphy of the SCH shows traces of the existence of earlier tectonic events. This study presents preliminary results of apatite fission-track (AFT) dating of sandstones from the Todos Santos Formation (Middle Jurassic). The analyses are performed with in situ uranium determination using LA-ICP-MS (e.g., Hasebe et al., 2004). The AFT data indicate that this Formation has suffered high-grade diagenesis (probably over 150 ºC) and the obtained cooling ages, about 70-60 Ma, correspond to a Late Cretaceous event. This tectonic event is contemporaneous with a startup of the Laramide Orogeny occurred in North America. The constructed time-temperature paths show the rapid cooling during the Middle-Late Miocene (15-10 Ma), like other published data. References: Hasebe et al. (2004) Chemical Geology, 207, 135-145 Witt et al. (2012) Tectonics, 31, TC6001, doi:10.1029/2012TC003141

  13. Stratigraphy of the Jurassic system in northern Egypt

    SciTech Connect

    Keeley, M.L.; Shaw, D.; Forbes, G.A.

    1988-08-01

    A regional synthesis is presented of the stratigraphy of Jurassic strata in Egypt north of 30/degree/N, based on the study of about 80 wells and outcrops from northeastern Egypt. Almost all fossil groups have been investigated for biostratigraphic control. Published work on ammonite faunas from Gebel el Maghara (north Sinai) is integrated with extensive original work on palynofloras (and, to a lesser extent, ostracod/foraminiferal faunas) recovered from marine rocks in the subsurface. The recovery of rich dinocyst assemblages enables the recognition of a ten-fold zonation scheme, largely within the Middle-Late Jurassic sedimentary package. The upper limit of this package is marked by the Cimmerian erosional event; strata younger than Oxfordian are rarely preserved. Only east of 30/degree/E is significant sedimentation known to have occurred immediately prior to the major early Bajocian transgressive event. Thereafter mean sea level rose steadily. The Lower Triassic-Lower Jurassic sedimentary package is poorly understood, largely the result of scanty and ambiguous stratigraphic evidence. However, regional correlations suggest that only very thin earliest Jurassic (Hettangian ) clastic deposition succeeded a sequence of Upper Triassic carbonates and evaporites (Wadi en Natrun Formation) in the north. Arising from these studies is a standard lithostratigraphical scheme. The upper sedimentary package, the Gebel el Maghara Group, comprises three formations (Masajid, Khatatba, and Inmar) and seven members; new units are defined and old units redefined.

  14. Jurassic Park as a Teaching Tool in the Chemistry Classroom.

    ERIC Educational Resources Information Center

    Jollis, W. Gary, Jr.

    1996-01-01

    Describes how the science fiction novel "Jurassic Park" has been used to provide the focus for summate discussions among gifted high school students participating in a state-sponsored, science-intensive summer program. Discusses adaptations of this approach for use in chemistry classes from the high school to intermediate college level. (JRH)

  15. Evidence for a Mid-Jurassic Adaptive Radiation in Mammals.

    PubMed

    Close, Roger A; Friedman, Matt; Lloyd, Graeme T; Benson, Roger B J

    2015-08-17

    A series of spectacular discoveries have transformed our understanding of Mesozoic mammals in recent years. These finds reveal hitherto-unsuspected ecomorphological diversity that suggests that mammals experienced a major adaptive radiation during the Middle to Late Jurassic. Patterns of mammalian macroevolution must be reinterpreted in light of these new discoveries, but only taxonomic diversity and limited aspects of morphological disparity have been quantified. We assess rates of morphological evolution and temporal patterns of disparity using large datasets of discrete characters. Rates of morphological evolution were significantly elevated prior to the Late Jurassic, with a pronounced peak occurring during the Early to Middle Jurassic. This intense burst of phenotypic innovation coincided with a stepwise increase in apparent long-term standing diversity and the attainment of maximum disparity, supporting a "short-fuse" model of early mammalian diversification. Rates then declined sharply, and remained significantly low until the end of the Mesozoic, even among therians. This supports the "long-fuse" model of diversification in Mesozoic therians. Our findings demonstrate that sustained morphological innovation in Triassic stem-group mammals culminated in a global adaptive radiation of crown-group members during the Early to Middle Jurassic. PMID:26190074

  16. Benthic aquatic ecosystems across the Permian-Triassic transition: record from biogenic structures in fluvial sandstones, central Transantarctic Mountains

    NASA Astrophysics Data System (ADS)

    Miller, M. F.

    2000-07-01

    The effect of the Permian extinction in communities inhabiting sandy stream bottoms can be evaluated using trace fossils as proxies for body fossils. Permian and Triassic sandstones exposed in the Beardmore and Shackleton Glacier areas (central Transantarctic Mountains) were deposited in sandy braided streams and contain four types of trace fossils (vertical shafts and horizontal, bilobed and chevron traces). These traces were produced by a single type of animal that moved in the top 30 cm of sediment and dominated the benthic community. Evidence for a single producer includes similar size (diameter) of all traces and change within single specimens from one trace type to another. The animal was not affected by the Permian extinction event, as evidenced by its equal abundance within the Permian (Buckley Formation) and Triassic (Fremouw Formation) fluvial sandstones in the Beardmore Glacier area. Based on trace morphology and on domination of modern sandy river ecosystems by insects, the producer most likely was an insect, although its more precise identity is problematic. Although families of insects with modern aquatic burrowers are not known before the Jurassic, these trace fossils may show that these burrowers were present earlier than the insect body-fossil record suggests. Alternatively, archaic insect groups, many of which became extinct at the end-Permian and are known to have been aquatic but not infaunal, may have included some active burrowers that were unscathed by the Permian extinction.

  17. Jurassic deposits of the southern part of the Irkutsk sedimentary basin

    NASA Astrophysics Data System (ADS)

    Akulov, N. I.; Frolov, A. O.; Mashchuk, I. M.; Akulova, V. V.

    2015-07-01

    This work presents new data on the lithology, paleontology, stratigraphy, and correlation of Jurassic deposits of the Irkutsk coal-bearing basin. According to the detailed analysis of the lithology and paleontology of the reference sections, the Jurassic deposits of the southern part of this basin are subdivided into four formations: Baikal'skaya, Dabatskaya, Cheremkhovskaya, and Prisayanskaya. The Lower Jurassic coarse deposits of the Baikal'skaya Formation are regarded as the most ancient; the Middle Jurassic deposits of the Prisayanskaya Formation are the youngest. The industrial coal-bearing deposits of the Cheremkhovskaya Formation formed in the Early Jurassic, from the Pliensbachian to Toarcian.

  18. Organic-inorganic interactions and sandstone diagenesis

    SciTech Connect

    Surdam, R.C.; Crossey, L.J.; Sven Hagen, E.; Heasler, H.P.

    1989-01-01

    The maturation of organic material in hydrocarbon source rocks and inorganic diagenetic reactions in reservoir sandstones are a natural consequence when a prism of sedimentary rocks is buried. The authors can predict the distribution of porosity and permeability enhancement in potential hydrocarbon reservoirs by integrating the reaction processes characterizing the progressive diagenesis of a reservoir/source rock system. A variety of observations suggests that the organic solvents needed to increase aluminosilicate and carbonate solubilities in sandstones can be generated either by thermal or oxidative cracking of carbonylic or phenolic groups from kerogen in adjacent source rocks. For example, nuclear magnetic resonance (NMR) spectra of kerogen show that peripheral carbonylic and phenolic groups are released from the kerogen molecule before liquid hydrocarbons are generated. Experimental data indicate these water-soluble organic species can significantly affect the stability of both carbonates and aluminosilicates. Water-soluble organic acid anions (carboxylic) have been observed in oil-field waters in concentrations up to 10,000 ppm, and they commonly dominate the alkalinity in the fluid phase from 80/degrees/ to 120/degrees/C.

  19. Hydrocarbon potential of a new Jurassic play, central Tunisia

    SciTech Connect

    Beall, A.O. ); Law, C.W. )

    1996-01-01

    A largely unrecognized Jurassic Sag Basin has been identified in central Tunisia, proximal to the Permo-Carboniferous flexure delineating the northern boundary of the Saharan platform of north Africa. The northwestern margin of the Sag is delineated by an extensive region of salt-cored anticlines and localized salt diapirs extending north and west. Due to lack of deep drilling, delineation of the Sag is largely based on regional gravity data. Subsidence of the Jurassic Sag Basin is characterized by rapid expansion of Jurassic sediments from 400 m. of tidal flat and shelf carbonate at the western outcrop to over 2000 meters of tidal flat and basinal carbonate and shale within the basin center, a five-fold expansion. Rapid loading of the basin continued into Lower Cretaceous time, marked by lateral flowage of Triassic salt into pronounced structural trends. Published source rock data and interpreted subsurface well data provided the basis for GENEX 1-D hydrocarbon generation and expulsion modeling of the Sag. Middle Jurassic black source shales typically contain Type II and Type III kerogens with T.O.C.'s ranging up to 4 percent. Modeling results indicate that middle Jurassic shales are presently mature for liquid generation within portions of the Sag, with maximum generation taking place during the Tertiary. Potential hydrocarbon generation yields, based on 60 meters of mature source shale, are 20,000 BOE/acre for gas and 75,000 BOE/acre for liquids. Prospects within the region could contain an estimated potential reserve of several T.C.F. or over 1 billion barrels of oil.

  20. Hydrocarbon potential of a new Jurassic play, central Tunisia

    SciTech Connect

    Beall, A.O.; Law, C.W.

    1996-12-31

    A largely unrecognized Jurassic Sag Basin has been identified in central Tunisia, proximal to the Permo-Carboniferous flexure delineating the northern boundary of the Saharan platform of north Africa. The northwestern margin of the Sag is delineated by an extensive region of salt-cored anticlines and localized salt diapirs extending north and west. Due to lack of deep drilling, delineation of the Sag is largely based on regional gravity data. Subsidence of the Jurassic Sag Basin is characterized by rapid expansion of Jurassic sediments from 400 m. of tidal flat and shelf carbonate at the western outcrop to over 2000 meters of tidal flat and basinal carbonate and shale within the basin center, a five-fold expansion. Rapid loading of the basin continued into Lower Cretaceous time, marked by lateral flowage of Triassic salt into pronounced structural trends. Published source rock data and interpreted subsurface well data provided the basis for GENEX 1-D hydrocarbon generation and expulsion modeling of the Sag. Middle Jurassic black source shales typically contain Type II and Type III kerogens with T.O.C.`s ranging up to 4 percent. Modeling results indicate that middle Jurassic shales are presently mature for liquid generation within portions of the Sag, with maximum generation taking place during the Tertiary. Potential hydrocarbon generation yields, based on 60 meters of mature source shale, are 20,000 BOE/acre for gas and 75,000 BOE/acre for liquids. Prospects within the region could contain an estimated potential reserve of several T.C.F. or over 1 billion barrels of oil.

  1. Geochemistry of vanadium in an epigenetic, sandstone-hosted vanadium- uranium deposit, Henry Basin, Utah

    USGS Publications Warehouse

    Wanty, R.B.; Goldhaber, M.B.; Northrop, H.R.

    1990-01-01

    The epigenetic Tony M vanadium-uranium orebody in south-central Utah is hosted in fluvial sandstones of the Morrison Formation (Upper Jurassic). Measurements of the relative amounts of V+3 and V +4 in ore minerals show that V+3 is more abundant. Thermodynamic calculations show that vanadium was more likely transported to the site of mineralization as V+4. The ore formed as V+4 was reduced by hydrogen sulfide, followed by hydrolysis and precipitation of V+3 in oxide minerals or chlorite. Uranium was transported as uranyl ion (U+6), or some complex thereof, and reduced by hydrogen sulfide, forming coffinite. Detrital organic matter in the rocks served as the carbon source for sulfate-reducing bacteria. Vanadium most likely was derived from the dissolution of iron-titanium oxides. Uranium probably was derived from the overlying Brushy Basin Member of the Morrison Formation. Previous studies have shown that the ore formed at the density-stratified interface between a basinal brine and dilute meteoric water. The mineralization processes described above occurred within the mixing zone between these two fluids. -from Authors

  2. Preservation of anomalously high porosity in deeply buried sandstones by grain-coating chlorite: Examples from the Norwegian Continental Shelf

    SciTech Connect

    Ehrenberg, S.N. )

    1993-07-01

    Five Lower to Middle Jurassic sandstone reservoirs from the Norwegian sector provide examples of deep porosity preservation caused by grain-coating, authigenic chlorite. Wide porosity variations in clean sandstones correlate with an abundance of grain-coating chlorite and consequent inhibition of quarts cementation. Maximum porosities tend to decrease with increasing depth but generally are 10-15% higher than would be predicted from regional trends of mean porosity vs. depth. It is proposed in this paper that the high chlorite content of the porous zones reflects syndepositional concentration of Fe-rich marine clays analogous to minerals of the modern verdine facies. Fe-clay mineralization would have been localized where Fe-rich river water was discharged into the sea. The syndepositional clays were transformed during burial diagenesis into grain coatings of radially oriented chlorite crystals. Petrographic relationships indicate that these coatings grew mainly before the beginning of quartz cementation and feldspar grain dissolution (probably within the first 2 km of burial) but after grain contacts had become adjusted by mechanical compaction. The Norwegian examples demonstrate that a wide range of nearshore marine sand-body types is susceptible to chlorite mineralization. The distribution of anomalous porosity and the proportion of the net sand affected depend upon sedimentary facies architecture and the pattern of discharge of Fe-rich river water during sand deposition. This phenomenon can be critically important for hydrocarbon exploration because it can provide good reservoir quality at depths far below the [open quotes]economic basement[close quotes] originally defined on the basis of sandstones lacking chlorite coatings. 58 refs., 25 figs., 1 tab.

  3. Building a Seismic Sequence Stratigraphy Model Using HorizonCubes: A Jurassic Case Study in the Arabian Basin

    NASA Astrophysics Data System (ADS)

    AlYousuf, T. Y.

    2012-12-01

    Understanding the regional stratigraphic framework of the Middle and Upper Jurassic (Late Callovian-Oxfordian - Early Kimmeridgian) formations in the Arabian Basin is extremely important for unlocking the area's hydrocarbon potential. With recent advances in computing power and interpretation software, seismic sequence stratigraphy has become an important tool in reservoir characterization, and for reducing exploration risk. This paper provides a workflow that can be used to model seismic horizons using a dip steering volume. The workflow consists of data conditioning to produce a dip steering volume to generate a volume of densely spaced, automatically tracked seismic horizons, a "HorizonCube". The horizons are derived from the dip and azimuth information stored in the dip steered seismic volume model. In the Wheeler domain, the seismic volume is recomputed and flattened accordingly to match the Wheeler transformed HorizonCube. Based on the HorizonCube model, it is possible to identify stratigraphic carbonate buildups and depositional sequences. Isolating the horizon cube into smaller packages shows the dynamic variation in the deposition of sediments through time and space during the Jurassic period, starting from the top of Minjur sandstone to the Arab D limestone. The geologist is also able to identify system tracts with stratigraphic surfaces and estimate a stratigraphic base level curve. The approach is extended to integrate with the well correlation panel for better confidence in picking well tops. Visualizing system tract-interpretations together with the HorizonCube and overlaying the seismic and Wheeler-transformed domains helps to identify depositional features of interest that may form stratigraphic traps.

  4. Comparison of geology of Jurassic Norphlet Mary Ann field, Mobile Bay, Alabama, to onshore regional Norphlet trends

    SciTech Connect

    Marzono, M.; Pense, G.; Andronaco, P.

    1988-09-01

    The geology of the Mary Ann field is better understood in light of regional studies, which help to establish a depositional model in terms of both facies and thickness variations. These studies also illustrate major differences between onshore and offshore Norphlet deposits concerning topics such as diagenesis, hydrocarbon trapping, and migration. The Jurassic Norphlet sandstone was deposited in an arid basin extending from east Texas to Florida by a fluvial-eolian depositional system, prior to the transgression of the Smackover Formation. Until discovery of the Mary Ann field in 1979, Norphlet production was restricted to onshore areas, mostly along the Pickens-Pollard fault system in Mississippi, Alabama, and Florida. The Mary Ann field is a Norphlet dry-gas accumulation, and was the first offshore field in the Gulf of Mexico to establish economic reserves in the Jurassic. The field is located in Mobile Bay, approximately 25 mi (40 km) south of Mobile, Alabama. Formed by a deep-seated (more than 20,000 ft or 6096 m) faulted salt pillow, Mary Ann field produces from a series of stacked eolian dune sands situated near the Norphlet paleocoastline. Five lithofacies have been recognized in cores from the Mobil 76 No. 2 well. Each lithofacies has a distinct reservoir quality. Optimum reservoir faces are the dune and sheet sands. Nonreservoir facies are interdune (wet and dry), marine reworked, and evaporitic sands. Following deposition, these sediments have undergone varying amounts of diagenesis. Early cementation of well-sorted sands supported the pore system during compaction. However, late cementation by chlorite, silica, and alteration of liquid hydrocarbons to an asphaltic residue have completely occluded the pore system in parts of the reservoir.

  5. Geologic aspects of reservoir souring - Brent Group sandstones, North Sea: The use of conventional and laser extraction techniques in sulfur isotope studies of authigenic pyrite

    SciTech Connect

    Brint, J.F. ); Fallick, A.E. )

    1991-03-01

    The Middle Jurassic Brent Group sandstones are prolific oil reservoirs in the North Sea. Recently, a number of Brent wells have experienced increased levels of hydrogen sulfide contamination during production. A study involving the characterization of all iron-bearing minerals to understand the controls of mineralogy on the nature and timing of souring has been undertaken. The potential of iron minerals to scavenge hydrogen sulfide and hence delay/inhibit souring by precipitation of pyrite has been investigated by determining its distribution, quantity, and origin. Authigenic pyrite occurs as disseminated (framboidal, cubic, and octahedral) crystals and as a pore-filling cement. The pyrite has formed throughout the diagenetic history of the sandstones. however, most of the pyrite is considered to be a late cement formed during burial diagenesis. Conventional separation and sulfur isotope analysis of the authigenic pyrite was conducted on samples from oil- and water-bearing sequences to give a bulk signature for all pyrite present. Subsequently, laser sulfur isotope analysis was used to characterize the signature and origin of the different pyrite morphologies present. The enhanced level of sulfur isotope signature characterization can be used to improve the knowledge of the origin and timing of the different pyrite morphologies. This allows closer reconciliation of the isotopic data to the diagenetic history of the Brent sandstones. Calculations have been made using the known quantities of iron in these minerals and the hydrogen sulfide concentrations present. This indicates the effect of sulfide precipitation on the hydrogen sulfide levels remaining in the reservoir.

  6. The Navajo Environmental Protection Commission: Developing the Capabilities for Environmental Impact Assessment and Regulation

    ERIC Educational Resources Information Center

    Cortner, Hanna J.

    1976-01-01

    To develop effective/efficient environmental impact assessment and regulatory capabilities, the Navajo Environmental Protection Commission will need to commit more of its limited resources to building the political support which will exert real influence at the pre-commitment stages of development decision making. (JC)

  7. Qualitative Study of the Use of Traditional Healing by Asthmatic Navajo Families

    ERIC Educational Resources Information Center

    Van Sickle, David; Morgan, Frank; Wright, Anne L.

    2003-01-01

    Despite increasing prevalence of asthma among American Indians and/or Alaska Natives, little is known about their use of traditional healing in its management. A convenience sample of 24 Navajo families with asthmatic members (n=35) was interviewed between June 1997 and September 1998. While 46% of families had previously used traditional healing,…

  8. Learn in Beauty: A Professional Development Project for Navajo Bilingual Teachers.

    ERIC Educational Resources Information Center

    Lockard, Louise; de Groat, Jennie; Bedonie, Clara

    The Learn in Beauty Project at Northern Arizona University worked with a consortium of seven Navajo Nation school districts seeking to implement the Dine Language and Culture teaching perspective. This perspective is based on the premises that education is best when it reflects a sense of place; education should be based on the philosophy and…

  9. 40 CFR 49.5512 - Federal Implementation Plan Provisions for Four Corners Power Plant, Navajo Nation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Federal Implementation Plan Provisions for Four Corners Power Plant, Navajo Nation. 49.5512 Section 49.5512 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE INDIAN COUNTRY: AIR QUALITY PLANNING AND MANAGEMENT Implementation Plans...

  10. Native American Navajo Teenage Parenting Women, Cross-Generational Support and Implications for Policy.

    ERIC Educational Resources Information Center

    Dalla, Rochelle L.; Gamble, Wendy C.

    This study examined teenage parenting among Native Americans, focusing on the support received from grandmothers. The sample was comprised of 15 subjects living on a Navajo reservation: 8 adolescent mothers between 16 to 19 years--most with one child and enrolled either in high school or in an alternative education program; and seven women…

  11. 75 FR 16174 - Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing Permits; Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-31

    ... collection of information was published on February 24, 2010 (75 FR 8731). No comments were received. This... collection is currently authorized by OMB Control Number 1076-0162, which expires March 31, 2010. The... collection activity. III. Data OMB Control Number: 1076-0162. Title: Navajo Partitioned Lands Grazing...

  12. The Economic Contributions of Women in a Rural Western Navajo Community.

    ERIC Educational Resources Information Center

    Russell, Scott C.; McDonald, Mark B.

    1982-01-01

    Examines and enumerates economic changes that have occurred in the traditional rural Navajo community of Shonto. While women's net income contributions to Shonto's economy has declined, their position has seen only a slight erosion; their activities (sheep and goat husbandry, agriculture, arts and crafts) are still considered necessary and…

  13. Perspectives of Adjustment: Rural Navajo and Papago Youth. Volume 2 of a Four Volume Final Report.

    ERIC Educational Resources Information Center

    Belding, Nancye; And Others

    Based on a literature survey (1965-70 publications) and personal interviews with southwestern Indian leaders, urban employers, and college teachers (recognized authorities on Indian problems), this research program was directed toward optimizing the benefits of youth projects for Navajo and Papago Indians and focused on factors related to social

  14. SUSTAINABILITY OF MOUNTAIN SOURCES OF WATER FOR THE NAVAJO NATION UNDER THE IMPACT OF CLIMATE CHANGE

    EPA Science Inventory

    This model may assist Navajo communities to implement strategies that prepare the communities for impacts of climate change. Other tribes may be encouraged to develop similar hydrologic models to help understand the hydrologic responses of climate change in their area and h...

  15. The Economic Contributions of Women in a Rural Western Navajo Community.

    ERIC Educational Resources Information Center

    Russell, Scott C.; McDonald, Mark B.

    1982-01-01

    Examines and enumerates economic changes that have occurred in the traditional rural Navajo community of Shonto. While women's net income contributions to Shonto's economy has declined, their position has seen only a slight erosion; their activities (sheep and goat husbandry, agriculture, arts and crafts) are still considered necessary and

  16. Of Mother Earth and Father Sky: A Photographic Study of Navajo Culture.

    ERIC Educational Resources Information Center

    McCarty, T. L.; And Others

    Utilizing 52 black and white photographs, the book tells a story about the Navajo people, their hopes and problems, the strategies they have adopted to cope with the problems, their interactions with each other and with the land, and their feelings about the land which provides a basis for their livelihood. Part of a series of curriculum materials

  17. Mathematics Anxiety and Learning Style of the Navajo Middle School Student.

    ERIC Educational Resources Information Center

    Hadfield, Oakley D.; And Others

    1992-01-01

    Presents a study to investigate the prevalence of mathematics anxiety in Navajo middle school students (n=358) and to explore possible relationships between learning styles and mathematics anxiety and achievement. Multiple regression procedures indicated that spatial ability and mathematics achievement were negatively correlated to mathematics

  18. The Navajo Learning Network and the NASA Life Sciences/AFOSR Infrastructure Development Project

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The NSF-funded Navajo Learning Network project, with help from NASA Life Sciences and AFOSR, enabled Dine College to take a giant leap forward technologically - in a way that could never had been possible had these projects been managed separately. The combination of these and other efforts created a network of over 500 computers located at ten sites across the Navajo reservation. Additionally, the college was able to install a modern telephone system which shares network data, and purchase a new higher education management system. The NASA Life Sciences funds further allowed the college library system to go online and become available to the entire campus community. NSF, NASA and AFOSR are committed to improving minority access to higher education opportunities and promoting faculty development and undergraduate research through infrastructure support and development. This project has begun to address critical inequalities in access to science, mathematics, engineering and technology for Navajo students and educators. As a result, Navajo K-12 education has been bolstered and Dine College will therefore better prepare students to transfer successfully to four-year institutions. Due to the integration of the NSF and NASA/AFOSR components of the project, a unified project report is appropriate.

  19. Navajo Electrification for Sustainable Development: The Potential Economic and Social Benefits

    ERIC Educational Resources Information Center

    Ballentine, Crystal; DeSouza, Anil; Bain, Craig; Majure, Lisa; Smith, Dean Howard; Turek, Jill

    2004-01-01

    The concomitant secondary consequences of an electrification program and the potential long-term benefits of such a program are described. An electrification program can stimulate a move toward true self-determination and self-sufficiency for the Navajo nation.

  20. Student Teachers' Reflections on Service and Learning in Navajo Reservation Communities: Contextualizing the Classroom Experience

    ERIC Educational Resources Information Center

    Statchowski, Laura L.; Frey, Cristopher J.

    2005-01-01

    This report reviews service learning activities performed by student teachers in the American Indian Reservation Project in their placement communities across the Navajo Nation. Parameters for this required, academic assignment included the selection of activities independent of their schools' academic or extracurricular programs; completion of

  1. Cross Country, Rodeo, Archery: Navajo Athletic Programs Give Students Running Start

    ERIC Educational Resources Information Center

    Johnson, Natasha Kaye

    2009-01-01

    While tribal college athletic programs were not designed to market the colleges, there is no denying they have generated positive attention and have perhaps even helped to highlight the colleges' purpose. Dine College and Navajo Technical College are among a handful of tribal colleges who have made athletic programs a priority. They have since

  2. Using the WISC-III with Navajo Children: A Need for Local Norms.

    ERIC Educational Resources Information Center

    McLellan, Mary J.; Nellis, Leah

    2003-01-01

    The Wechsler Intelligence Scale for Children-Third Edition (WISC-III) was administered to 175 Navajo children at 2 reservation elementary schools. Local normative information was developed to reduce test bias associated with the English-laden content in the test. A procedure was developed for converting WISC-III scores, enabling comparison of

  3. The Goal Wheel: Adapting Navajo Philosophy and the Medicine Wheel to Work with Adolescents

    ERIC Educational Resources Information Center

    Garner, Holly; Bruce, Mary Alice; Stellern, John

    2011-01-01

    The purpose of this article is to describe a group counseling model that is based on the indigenous medicine wheel as well as Navajo philosophy by which to help troubled adolescents restore harmony and balance in their lives, through establishing goals and sequential steps to accomplish these goals. The authors call this model the Goal Wheel. A

  4. Methods and Resources for the Construction and Maintenance of a Navajo Population Register.

    ERIC Educational Resources Information Center

    Kelly, William H.

    The most feasible method for constructing a Navajo population register was to produce a preliminary register from data contained in existing records and to perfect and extend this register either through subsequent clerical and record-accumulating operations, the existing school census operation, a special program of field enumeration, or a

  5. The Goal Wheel: Adapting Navajo Philosophy and the Medicine Wheel to Work with Adolescents

    ERIC Educational Resources Information Center

    Garner, Holly; Bruce, Mary Alice; Stellern, John

    2011-01-01

    The purpose of this article is to describe a group counseling model that is based on the indigenous medicine wheel as well as Navajo philosophy by which to help troubled adolescents restore harmony and balance in their lives, through establishing goals and sequential steps to accomplish these goals. The authors call this model the Goal Wheel. A…

  6. Cross Country, Rodeo, Archery: Navajo Athletic Programs Give Students Running Start

    ERIC Educational Resources Information Center

    Johnson, Natasha Kaye

    2009-01-01

    While tribal college athletic programs were not designed to market the colleges, there is no denying they have generated positive attention and have perhaps even helped to highlight the colleges' purpose. Dine College and Navajo Technical College are among a handful of tribal colleges who have made athletic programs a priority. They have since…

  7. Classroom Resiliency--A Comparison of Navajo Elementary Students' Perceptions of Their Classroom Environment

    ERIC Educational Resources Information Center

    Piechowski, Alta Begay

    2011-01-01

    The purpose of this study was to determine if there was a gender difference in how students perceived their classroom environment on the Navajo Nation public school. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be

  8. The Cognitive Consequences of Specific Experiences; Weaving versus Schooling among the Navajo.

    ERIC Educational Resources Information Center

    Rogoff, Barbara; Gauvain, Mary

    1984-01-01

    Reports on a study (of 79 Navajo women) that compared the predictiveness of two types of learning experience (schooling and weaving) for pattern continuation skills across varying domains and contexts. Questions the notion that what is learned in particular experiences automatically improves skills in general. (KH)

  9. From Break Dancing to Heavy Metal: Navajo Youth, Resistance, and Identity.

    ERIC Educational Resources Information Center

    Deyhle, Donna

    1998-01-01

    Research on Navajo youth lives and choices examines the messages conveyed through their breakdancing and heavy-metal music. Central to the messages is resistance to assimilation into mainstream culture and maintenance of their cultural identity in a racially divided community. (MMU)

  10. 25 CFR 161.101 - How will tribal laws be enforced on the Navajo Partitioned Lands?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... testimony set forth at 43 CFR part 2, subpart E; (ii) Constitute a waiver of the sovereign immunity of the... 25 CFR, so long as the new waiver does not violate a federal statute or judicial decision or conflict... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to...

  11. 25 CFR 161.101 - How will tribal laws be enforced on the Navajo Partitioned Lands?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... testimony set forth at 43 CFR part 2, subpart E; (ii) Constitute a waiver of the sovereign immunity of the... 25 CFR, so long as the new waiver does not violate a federal statute or judicial decision or conflict... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to...

  12. 25 CFR 161.101 - How will tribal laws be enforced on the Navajo Partitioned Lands?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... testimony set forth at 43 CFR part 2, subpart E; (ii) Constitute a waiver of the sovereign immunity of the... 25 CFR, so long as the new waiver does not violate a federal statute or judicial decision or conflict... WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits ...

  13. 25 CFR 161.101 - How will tribal laws be enforced on the Navajo Partitioned Lands?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... testimony set forth at 43 CFR part 2, subpart E; (ii) Constitute a waiver of the sovereign immunity of the... 25 CFR, so long as the new waiver does not violate a federal statute or judicial decision or conflict... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to...

  14. 25 CFR 161.101 - How will tribal laws be enforced on the Navajo Partitioned Lands?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... testimony set forth at 43 CFR part 2, subpart E; (ii) Constitute a waiver of the sovereign immunity of the... 25 CFR, so long as the new waiver does not violate a federal statute or judicial decision or conflict... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to...

  15. Maslow's Hierarchy of Needs and Navajo Students' Struggle for Self Esteem.

    ERIC Educational Resources Information Center

    Walker, Kay

    1996-01-01

    Maslow's theory of a hierarchy of needs is used to analyze Navajo youths' struggles for identity, fulfillment, and self-esteem. Answers to the challenges of substance abuse, violence, and gang membership are offered based upon George Bearden's eight-step plan, which stresses the importance of understanding human needs to perceive and transform

  16. 30 CFR 756.15 - Required amendments to the Navajo Nation's abandoned mine land plan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... abandoned mine land plan. 756.15 Section 756.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS 756.15 Required amendments to the Navajo Nation's abandoned mine land plan. Pursuant to 30...

  17. Behavioral Characteristics of Gifted Navajo Students as Correlated with Intellectual Ability and Creativity.

    ERIC Educational Resources Information Center

    Julien, Paul Daniel; Ostertag, Bruce Andrew

    The Structure of Intellect Learning Abilities (SOI-LA) Test was administered to 244 Navajo students (second through eighth grades) at Leupp Boarding School in northern Arizona to determine behavioral characteristics in regard to intellectual and creative ability. Comparison of SOI-LA test scores of Leupp students with norm scores revealed 54 of…

  18. 30 CFR 756.14 - Approval of amendments to the Navajo Nation's abandoned mine land plan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Approval of amendments to the Navajo Nation's abandoned mine land plan. 756.14 Section 756.14 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.14 Approval...

  19. Sandstone porosity as a function of thermal maturity

    USGS Publications Warehouse

    Schmoker, J.W.; Gautier, D.L.

    1988-01-01

    The commonly observed exponential dependence of sandstone porosity upon depth follows as a special case from this power-function relation when temperature increases linearly with depth. The consideration of sandstone porosity in terms of time-temperature exposure offers advantages in the comparison of porosity data from diverse geologic settings. -from Authors

  20. Diagenesis of the Almond sandstone in the Washakie Basin

    SciTech Connect

    Yin, Peigui; Liu, Jie; Surdam, C.R. . Dept. of Geology and Geophysics)

    1992-01-01

    The marginal marine and nonmarine Almond sandstones are mostly sublitharenite, litharenite, and lithic arkose. The sandstones are fine-to very-fine-grained, and are well-sorted. The framework composition, authigenic minerals, and porosity and permeability distributions in the Almond sandstones are different below and above 8,000 feet, resulting in a variation in hydrocarbon reservoir types. The shallow conventional reservoirs are permeable, producing both liquid oil and gas, whereas the deep gas-bearing sandstones are very tight and overpressured. Porosity of the shallow Almond sandstones have been significantly enhanced by dissolution of the feldspar grains and lithic fragments. Quartz overgrowth cement and authigenic clay rims have occluded most of the intergranular pores, as well as the previously leached pores. The Almond sandstones have been buried deeper than their present depths. The sandstones in each part of the Washakie Basin have experienced different uplift and subsidence. Reconstruction of the burial history and diagenetic modeling are essential steps for understanding the diagenetic evolution of the Almond sandstones.