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1

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

PubMed Central

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.

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

2010-01-01

2

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

NASA Astrophysics Data System (ADS)

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.

Bryant, Gerald; Monegato, Giovanni; Miall, Andrew

2013-11-01

3

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

Microsoft Academic Search

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

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

2010-01-01

4

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

USGS Publications Warehouse

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.

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

2010-01-01

5

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

NASA Astrophysics Data System (ADS)

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.

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

2010-11-01

6

Tracing paleofluid circulations using iron isotopes: A study of hematite and goethite concretions from the Navajo Sandstone (Utah, USA)  

Microsoft Academic Search

Iron concentrations and isotopic compositions were measured in spherical hematite and goethite concretions, together with associated red (Fe-oxide coated) and white (bleached) sandstones from the Jurassic Navajo formation, Utah (USA). Earlier studies showed that, in the Navajo Sandstone, reducing fluids (presumably rich in hydrocarbons) mobilized Fe present as Fe-oxide coatings on detrital quartz grains. Dissolved Fe then precipitated as spherical

Vincent Busigny; Nicolas Dauphas

2007-01-01

7

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

NASA Astrophysics Data System (ADS)

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.

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

8

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

NASA Astrophysics Data System (ADS)

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 ˜10 5 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.

Zhu, Chen; Veblen, David R.; Blum, Alex E.; Chipera, Stephen J.

2006-09-01

9

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

NASA Astrophysics Data System (ADS)

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 (?m- 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.

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

2011-01-01

10

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

USGS Publications Warehouse

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.

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

1979-01-01

11

The Middle Jurassic Entrada Sandstone near Gallup, New Mexico  

USGS Publications Warehouse

Near Gallup, New Mexico, the Middle Jurassic Entrada Sandstone consists of, in ascending order, the Iyanbito Member, the Rehoboth Member, and an upper sandstone member. The Rehoboth Member is named herein to replace the middle siltstone member, with a type section located 26 km east of Gallup. The Iyanbito Member has been erroneously equated with the Wingate Sandstone of northeast Arizona, and the Rehoboth Member has been miscorrelated with the Dewey Bridge Member of the Entrada in Utah. The Dewey Bridge is an older unit that does not extend into New Mexico. The Iyanbito Member, east of Gallup, overlies the J-2 unconformity and the eroded tops of the Owl Rock and Petrified Forest Members of the Chinle Formation. The Wingate Sandstone of the Lower Jurassic Glen Canyon Group overlies the J-0 unconformity and the underlying Rock Point Member (topmost unit) of the Chinle Formation in northeast Arizona. Both the Wingate Sandstone and the Rock Point Member are missing east of Gallup below the J-2 unconformity. Similarly, the Wingate is missing southwest of Gallup, near Lupton, Arizona, but the Rock Point Member is present and underlies the Iyanbito from Zuni northward to Toadlena, New Mexico. The Wingate and other formations of the Glen Canyon Group thin and wedge out southward and eastward in northeast Arizona. The J-2 unconformity truncates the Wingate Sandstone and the underlying J-0 unconformity, 5 km north of Toadlena.

Robertson, J. F.; O'Sullivan, R. B.

2001-01-01

12

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

NASA Astrophysics Data System (ADS)

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.

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

2008-03-01

13

Oxidative dissolution of uraninite precipitated on Navajo sandstone  

Microsoft Academic Search

Column and batch experiments were conducted with sandstone and ground water samples to investigate oxidation of uraninite precipitated by microbially mediated reduction of U(VI), a contaminant in ground water beneath a uranium mill tailings site near Tuba City, AZ, USA. Uraninite precipitated together with mackinawite (FeS0.9) because Fe(III) from the sandstone and sulfate, another contaminant in the water were reduced

A Abdelouas; W Lutze; H. E Nuttall

1999-01-01

14

Oxidative dissolution of uraninite precipitated on Navajo sandstone  

NASA Astrophysics Data System (ADS)

Column and batch experiments were conducted with sandstone and ground water samples to investigate oxidation of uraninite precipitated by microbially mediated reduction of U(VI), a contaminant in ground water beneath a uranium mill tailings site near Tuba City, AZ, USA. Uraninite precipitated together with mackinawite (FeS 0.9) because Fe(III) from the sandstone and sulfate, another contaminant in the water were reduced together with U(VI). After completion of U(VI) reduction, experiments were conducted to find out whether uraninite is protected by mackinawite against reoxidation. Uncontaminated ground water from the same site, containing 7 mg/l of dissolved oxygen, was passed through the columns or mixed with sandstone in batch experiments. The results showed that small masses of uraninite, 0.1 ?g/g of sandstone, are protected by mackinawite from reoxidation. Uraninite masses on the order of 0.1 ?g/g correspond to U(VI) concentrations of 0.5 mg/l, typically encountered in uranium contaminated ground waters. Mackinawite is an effective buffer and is formed in sufficient quantity to provide long-term protection of uraninite. Uranium concentrations in ground water passed through the columns are too low (4 ?g/l) to distinguish between dissolution and oxidative dissolution of uraninite. However, batch experiments showed that uraninite oxidation takes place.

Abdelouas, A.; Lutze, W.; Nuttall, H. E.

1999-03-01

15

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

USGS Publications Warehouse

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.

Heilweil, Victor M.; McKinney, Tim S.

2007-01-01

16

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

NASA Astrophysics Data System (ADS)

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.

Zhu, C.

2009-12-01

17

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

18

Frisco City sandstone: Upper Jurassic play in southern Alabama  

Microsoft Academic Search

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 km² in

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

1997-01-01

19

Haynesville sandstone reservoirs in the Updip Jurassic trend of Alabama  

SciTech Connect

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.

Kugler, R.L.; Mink, R.M. [Geological Survey of Alabama, Tuscaloosa, AL (United States)

1994-09-01

20

Compaction bands: a structural analog for anti-mode I cracks in aeolian sandstone  

Microsoft Academic Search

We present evidence for the existence of tabular zones of localized deformation in aeolian sandstone, that accommodate pure compaction. In this sense they are analogs for anticracks or closing mode I fractures such as pressure solution surfaces or stylolites. The so called “compaction bands” are exposed in outcrops of the Jurassic Navajo Sandstone in the Kaibab monocline, Utah. They are

P. N. Mollema; M. A. Antonellini

1996-01-01

21

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

SciTech Connect

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.

Levy, J.B.

1985-02-01

22

Sedimentology and sequence stratigraphy of paralic and shallow marine Upper Jurassic sandstones in the northern Danish Central Graben  

Microsoft Academic Search

Paralic and shallow marine sandstones were deposited in the Danish Central Graben during Late Jurassic rifting when half-grabens were developed and the overall eustatic sea level rose. During the Kimmeridgian, an extensive plateau area consisting of the Heno Plateau and the Gertrud Plateau was situated between two highs, the Mandal High to the north, and the combined Inge and Mads

Peter N. Johannessen

23

Rb-Sr and K-Ar dating of clay diagenesis in Jurassic sandstone oil reservoir, North Sea  

SciTech Connect

Rb-Sr and K-Ar isotopic determinations were combined with scanning electron microscopy (SEM) observations and x-ray diffractometry (XRD) controls to date the diagenetic formation of clay minerals from oil-bearing sandstones of the Middle Jurassic Brent Sandstone in the North Sea. The separated clay fractions often contain detrital components, especially K-feldspars, which are reduced to sizes smaller than 0.4 ..mu..m either by intense in-situ alteration or by destructive sample preparation. Direct Rb-Sr and K-Ar isotopic dating of diagenetic illite therefore was not possible. Isotopic data obtained on mixtures of detrital and newly formed components showed, however, that illite formed about 40 to 45 Ma. This value also was obtained directly on clay fractions separated by a gentle method of disaggregation. Illitization is related to emplacement of hydrocarbons and associated waters into the formation. Aqueous and hydrocarbon fluids simultaneously trapped in quartz-overgrowth inclusions indicate late silicification contemporaneous with this fluid migration. Minimum trapping temperatures of at least 110/sup 0/C for these fluid inclusions are too high for the present burial depth. Hot fluids are assumed to have originated in deep source rocks beneath the Brent reservoirs and migrated upward during the middle Eocene. 7 figures, 3 tables.

Liewig, N.; Clauer, N.; Sommer, F.

1987-12-01

24

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

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.

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

1995-04-01

25

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

SciTech Connect

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.

Blakey, R.C.; Jones, L.S. [Northern Arizona Univ., Flagstaff, AZ (United States). Dept. of Geology; Havholm, K.G. [Univ. of Wisconsin, EauClaire, WI (United States). Dept. of Geology

1996-03-01

26

Navajo Nation  

NSDL National Science Digital Library

This site is an informational website about Navajo culture. Information includes the meaning of the Navajo flag, the origin of the Navajo people, the four worlds of the Navajo, the significance of the four directions (north, south, east, west) to the Navajo, language, family and culture. Users may also follow links to information on other Native American cultures, an ancient civilization index, and an alphabetical list of all files in the Crystalinks website.

Ellie, Crystal; Crystalinks

27

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)

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.

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

2004-12-01

28

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

29

Navajo (Dine)  

NSDL National Science Digital Library

This website consists of a fact sheet that provides a brief account of the ancient and modern history the Navajo peoples. The text discusses the Navajo transition from nomadic hunting and gathering people in the early Spanish period to the sheep herding, blanket-weaving peoples of the nineteenth century. Links within the text lead to a glossary of terms and additional information about the history and cultural heritage of the Navajo peoples.

John, Grahame; Colorado Plateau Field Station; Northern Arizona University

30

Navajo Indians  

NSDL National Science Digital Library

Let's learn about Utah History! Let's learn about the Navajo Indians. Learning Objective After reading and researching information about the Navajo tribe, students will be able understand the culture and traditions of this tribe and make comparisons to their own culture, by researching, writing about and creating Navajo jewelry and completing a cultural comparison worksheet. Grades 3 4th Grade Content Area(s) Social Studies Content Targets History, culture ...

Chamberlain, Keshia

2009-11-28

31

THE NAVAJOS.  

ERIC Educational Resources Information Center

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…

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

32

Navajo Country  

NSDL National Science Digital Library

This map of the Navajo Nation illustrates settlements, landforms, water features, parks, forests, and neighboring Indian reservations. The map index provides links to additional information about some of these features.

Harrison, Lapahie

33

Reservoir characterization of tight gas sand: Taylor sandstone (upper Cotton Valley group, upper Jurassic), Rusk County, Texas  

SciTech Connect

An integrated petrographic, sedimentologic, and log analysis study of the Taylor sandstone in Rusk County, Texas, was conducted to understand the geologic controls on reservoir performance and to identify pay zones for reserves calculations. The Taylor sandstone interval consists of tightly cemented, fine-grained quartzose sandstones interbedded with mudstones, siltstones, and carbonates that occur in upward-coarsening sequences. Helium permeability rarely exceeds 0.1 md, and porosity is rarely greater than 10%. Relationships between porosity and permeability are diffuse because of a string diagenetic overprint. Six major rock types or petrofacies are distinguished on the basis of pore type and dominant cement mineralogy. Three sandstone petrofacies - primary macroporous quartz cemented, moldic macroporous quartz cemented, and microporous clay cemented - have reservoir potential. Although these petrofacies have similar porosities and permeabilities, fluid saturations differ considerably due to differences in pore geometry as indicated by petrographic and capillary pressure analyses. These three reservoir-quality petrofacies can each be identified directly on wireline logs by applying cutoffs to the porosity and normalized gamma-ray logs.

Vavra, C.L.; Scheihing, M.H.; Klein, J.D.

1989-03-01

34

Navajo Nation Teacher Education Initiative.  

ERIC Educational Resources Information Center

The Navajo Teacher Education Initiative was developed in 1992 to improve the quality of Navajo education through the recruitment and training of prospective Navajo educators. Currently, the 242 schools on or near the Navajo Nation are staffed primarily by non-Navajo teachers who often do not understand the significance of Navajo culture, history,…

Rude, Harvey; Gorman, Roxanne

35

Navajo Electrification Demonstraiton Project  

SciTech Connect

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.

Larry Ahasteen, Project Manager

2006-07-17

36

Strong Navajo Marriages  

ERIC Educational Resources Information Center

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:…

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

2008-01-01

37

Regional Diagenesis of Sandstones in the Upper Jurassic Morrison Formation, San Juan Basin, New Mexico and Colorado: Geologic, Chemical, and Kinetic Constraints.  

National Technical Information Service (NTIS)

The Upper Jurassic Morrison Formation is the major uranium- and vanadium-bearing unit on the Colorado Plateau and, as such, has been the focus of numerous sedimentologic, petrologic, and geochemical studies. As a result, most research has concentrated on ...

P. L. Hansley

1990-01-01

38

Sandstone/Shale-Brine-CO2 interactions: Implications for Geological Carbon Sequestration  

NASA Astrophysics Data System (ADS)

The injection of CO2 into deep saline aquifers is presently being considered as an option for greenhouse gas mitigation. However, significant amount of CO2-water-rock interactions brings uncertainties to this potential option because these interactions may either enhance or decrease the potential storage capacity of the reservoirs by dissolution of primary minerals and precipitation of secondary clays. In addition, these reactions may enhance or compromise the mechanical properties of the seals or cap rocks. A series of Sandstone/Shale-Brine-CO2 hydrothermal experiments have been performed at 200 oC, with the addition of CO2 (PCO2 up to 300 bars). Navajo sandstone samples were collected from Black Mesa, Arizona. The Jurassic Navajo/Nugget Sandstone is identified as regionally extensive in the western U.S. and selected as the target for one of the large-volume injection tests by the Big Sky Carbon Sequestration Partnership. Shale chips were obtained from the basal Eau Claire Formation in Southwest of Indiana. Eau Claire Shale overlies Mt. Simon Sandstone which is recognized as a highly promising host reservoir targeted for carbon sequestration by the Midwest Geological Sequestration Consortium (MGSC). Experiments of Navajo sandstones show that silicate minerals in the sandstone display dissolution textures. The formation of carbonate minerals (mineral trapping) is thermodynamically favored and experimentally observed. The chemical reactions likely increase the porosity of the sandstone due to silicate dissolution. However, allophane and illite/smectite cements fill voids of sandstone grains. There is no evidence that suggests the removal of clay coating due to chemical reactions. It is uncertain whether the mechanical forces near in the injection well would mobilize the smectite and allophane and cause pore clogging. In contrast, for CO2-brine-shale system, only minor dissolution of K-feldspar and anhydrite was observed. However, precipitation of pore-filling and pore-bridging illite and/or smectite, carbonates and halite efflorescence reduce the permeability and tend to make the rock more compact, thereby locally enhancing the integrity of the repository.

Lu, P.; Liu, F.; Fu, Q.; Seyfried, W. E.; Hedges, S.; Griffith, C.; Soong, Y.; Zhu, C.

2009-12-01

39

Navajo Biographies. Volume I.  

ERIC Educational Resources Information Center

The life stories of eight Navajo ("Dine", their term for themselves) leaders are presented in volume one of this collection of biographies. Interspersed with portraits, drawings, and maps, the narrative chronologically covers the time period from 1766 when the Navajos lived on land under the rule of Spain into the twentieth century and dealings…

Hoffman, Virginia

40

Navajo Biographies. Volume II.  

ERIC Educational Resources Information Center

The second of two volumes, this collection contains biographies of seven Navajo men and women chosen to represent Navajo leadership in the twentieth century. Originally appearing in a 1970 publication of the Rough Rock Demonstration School, the biographies appear here unchanged in order to make them available once again. In addition to the life…

Johnson, Broderick H.; Hoffman, Virginia

41

Our Friends -- The Navajos.  

ERIC Educational Resources Information Center

Papers in this collection reflect the academic and on-reservation learning experiences of institute participants exposed to: Indian arts and crafts; the Navajo language; the Navajo people in their own homes, schools, and communities; basic knowledge of Indians; ceremonies, community meetings, and neighboring reservations; and major problems and…

Navajo Community Coll. Press, Tsaile, AZ.

42

The Sociolinguistics of Navajo Literacy.  

ERIC Educational Resources Information Center

Develops a critique of the "special diglossia" idea: the notion that Navajos speak Navajo but read and write English. Describes uses for English and Navajo literacy in one community on the Navajo reservation. Applies concepts such as institution, ideology, power, and empowerment to these uses. (JS)

McLaughlin, Daniel

1989-01-01

43

Kinaalda: A Navajo Puberty Ceremony.  

ERIC Educational Resources Information Center

A bilingual (Navajo-English) book from the Navajo Curriculum Center, on the Kinaalda, the Navajo girls' puberty ceremony, is intended for Navajo students at the secondary and junior college level and contains a section introducing the ceremony and sections on early life experiences and the initiation into womanhood. All text in the three sections…

Begay, Shirley M.; And Others

44

Diabetes in Navajo Youth  

PubMed Central

OBJECTIVE—To estimate the prevalence and incidence of diabetes, clinical characteristics, and risk factors for chronic complications among Navajo youth, using data collected by the SEARCH for Diabetes in Youth Study (SEARCH study). RESEARCH DESIGN AND METHODS—The SEARCH study identified all prevalent cases of diabetes in 2001 and all incident cases in 2002–2005 among Navajo youth. We estimated denominators with the user population for eligible health care facilities. Youth with diabetes also attended a research visit that included questionnaires, physical examination, blood and urine collection, and extended medical record abstraction. RESULTS—Diabetes is infrequent among Navajo youth aged <10 years. However, both prevalence and incidence of diabetes are high in older youth. Among adolescents aged 15–19 years, 1 in 359 Navajo youth had diabetes in 2001 and 1 in 2,542 developed diabetes annually. The vast majority of diabetes among Navajo youth with diabetes is type 2, although type 1 diabetes is also present, especially among younger children. Navajo youth with either diabetes type were likely to have poor glycemic control, high prevalence of unhealthy behaviors, and evidence of severely depressed mood. Youth with type 2 diabetes had more metabolic factors associated with obesity and insulin resistance (abdominal fat deposition, dyslipidemia, and higher albumin-to-creatinine ratio) than youth with type 1 diabetes. CONCLUSIONS—Our data provide evidence that diabetes is an important health problem for Navajo youth. Targeted efforts aimed at primary prevention of diabetes in Navajo youth and efforts to prevent or delay the development of chronic complications among those with diabetes are warranted.

Dabelea, Dana; DeGroat, Joquetta; Sorrelman, Carmelita; Glass, Martia; Percy, Christopher A.; Avery, Charlene; Hu, Diana; D'Agostino, Ralph B.; Beyer, Jennifer; Imperatore, Giuseppina; Testaverde, Lisa; Klingensmith, Georgeanna; Hamman, Richard F.

2009-01-01

45

NAVAJO ELECTRIFICATION DEMONSTRATION PROJECT  

Microsoft Academic Search

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)

Terry W. Battiest

2008-01-01

46

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

ERIC Educational Resources Information Center

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.…

Eck, Norman K.

47

Navajo Reflections on Climate Change  

NSDL National Science Digital Library

In this video segment adapted from Navajo Technical College, meet two members of the Navajo Nation, one Elder and one scientist, as they share their observations about how precipitation has changed since they were children.

Foundation, Wgbh E.

2012-03-23

48

Navajos Sign an Apprenticeship Pact  

ERIC Educational Resources Information Center

Discusses the Navajo Tribe's joining with the AFL-CIO building and construction trades unions to develop an apprentice job training program geared to the special employment problems of Navajos and to the projected labor needs for construction projects on or near the reservation. Focus is on the Navajo Construction Industry Manpower Program…

Manning, Diane B.

1977-01-01

49

Reevaluation of upper Jurassic Morrison Formation, Western Interior  

Microsoft Academic Search

Comparison of the Brushy Basin member of the Upper Jurassic Morrison Formation in the Colorado Plateau with the Upper Jurassic-Lower Cretaceous Morrison-Cloverly sequence in the Bighorn basin, Wyoming, shows great similarities in their depositional environments and stratigraphy. The lower Brushy Basin member is a fluvial deposit composed of channel sandstones and overbank mudstones which display a great number of pedogenic

Mantzios

1989-01-01

50

So Many Kinds of Navajos.  

ERIC Educational Resources Information Center

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

Underhill, Ruth

51

Navajo Nation Educational Hearings, 1975.  

ERIC Educational Resources Information Center

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…

Navajo Tribe, Window Rock, AZ.

52

Dinetah: Navajo History. Volume II.  

ERIC Educational Resources Information Center

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

Roessel, Robert A., Jr.

53

Navajo Coal: Demands, Attitudes, and Environment.  

ERIC Educational Resources Information Center

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…

Goodman, James M.

54

Compaction bands: a structural analog for anti-mode I cracks in aeolian sandstone  

NASA Astrophysics Data System (ADS)

We present evidence for the existence of tabular zones of localized deformation in aeolian sandstone, that accommodate pure compaction. In this sense they are analogs for anticracks or closing mode I fractures such as pressure solution surfaces or stylolites. The so called "compaction bands" are exposed in outcrops of the Jurassic Navajo Sandstone in the Kaibab monocline, Utah. They are characterized by lack of shear offset across their plane, volume loss, micro fracturing and very little grain crushing or comminution. Based on their geometry, two kinds of compaction bands are distinguished: the first kind is 0.5-1.5 cm thick and fairly straight over lengths of about 5-10 m. The second kind is 0.1-0.5 cm thick over lengths up to 2 m, and is conspicuously crooked with wavelengths of 1-5 cm and amplitudes of a few mm to a few cm. Compaction bands preferentially developed in the compressive quadrant at the tips of small faults or "deformation band faults" which suggests, together with the direction of shear along the deformation band faults, that compaction bands form perpendicular to the largest compressive stresses induced by motion along the deformation band faults. Also, the compaction bands typically occur in sedimentary layers with large grain sizes (0.3-0.8 mm) and high porosity (20-25%) whereas the deformation band faults occur in the layers with smaller grain sizes (0.05-0.25 mm) and lower (< 20%) porosity.

Mollema, P. N.; Antonellini, M. A.

1996-12-01

55

Calsoyasuchus valliceps, a new crocodyliform from the Early Jurassic Kayenta Formation of Arizona  

Microsoft Academic Search

We describe a new fossil crocodyliform archosaur from the Early Jurassic Kayenta Formation of the Navajo Nation that is surprisingly derived for so ancient a specimen. High-resolution X-ray CT analysis reveals that its long snout houses an extensive system of pneumatic paranasal cavities. These are among the most distinctive features of modern crocodylians, yet the evolutionary history of this unique

Ronald S. Tykoski; Timothy B. Rowe; Richard A. Ketcham; Matthew W. Colbert

2002-01-01

56

Navajo Rug with English Voice  

NSDL National Science Digital Library

This interactive Flash lesson helps students to distinguish squares and triangles and be creative in the context of Navajo rug design. The animated pages give printed and voiced instructions in English. A teacher guide (pdf) is available - see #30 at MathActive Lessons for Grades K-2, cataloged separately. Navajo, Spanish, and non-spoken versions of the lesson are available also at the Lessons page.

Edgmon, Jeneen

2011-01-01

57

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

ERIC Educational Resources Information Center

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…

Holm, Wayne; Silentman, Irene; Wallace, Laura

58

Navajo Electrofication Demonstration Project, (Final Report).  

National Technical Information Service (NTIS)

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...

T. W. Battiest

2008-01-01

59

Impact of Marital Disruption in Navajo Children.  

National Technical Information Service (NTIS)

The aim of this project was to better understand the context, process, and impact of marital separation on the Navajo Reservation. The impact of rapid acculturation and economic change on the Navajo family was documented. In an ethnographic study, demogra...

R. C. Wood L. Hauswald

1983-01-01

60

A Utah Navajo History = Dineji Nakee' Naahane'  

ERIC Educational Resources Information Center

This book presents Navajo history in two aspects--traditional stories that describe the ancestors of the Navajo and explain how the Earth-Surface World was changed from monster-filled chaos into the well-ordered world of today, and historical events from 1525 to today after the Navajos had settled in the Southwest. Events described include…

Benally, Clyde; And Others

61

Navajo History: The Land and the People.  

ERIC Educational Resources Information Center

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…

Acrey, Bill P.

62

Navajo Pawn: A Misunderstood Traditional Trading Practice  

ERIC Educational Resources Information Center

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…

Kiser, William S.

2012-01-01

63

A Bibliographic Essay Pertaining to Navajo Indians.  

ERIC Educational Resources Information Center

Introduced by a discussion of the fact that most of the works cited describe Navajos as they "used to be" and an admonition against the common practice of placing all Navajos, or all Indians, under one stereotype, this bibliographic essay traces the history of Navajo contact with the white man and emphasizes efforts at educational development. Six…

Harrison, Scott

64

New Paper Words: Historical Images of Navajo Literacy.  

ERIC Educational Resources Information Center

Weaves a Navajo elementary teacher's anecdotes from her own and her father's educational experiences with archival materials to provide a historical context for Navajo literacy. Discusses early written Navajo; the role of schools and churches in the expansion of written Navajo; and the advancement of Navajo linguistics during John Collier's…

Lockard, Louise

1996-01-01

65

Compensation of Navajo Uranium Miners  

NSDL National Science Digital Library

This site addresses policy issues of the compensation of Navajo uranium miners. The site provides an annotated index of current issues, legislation, papers and presentations, books, and links that lead to more information on uranium miners. Imbedded links throughout the text lead to related information.

Project, World I.

66

Navajos and National Nuclear Policy.  

ERIC Educational Resources Information Center

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)

Barry, Tom

1979-01-01

67

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

ERIC Educational Resources Information Center

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…

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

68

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)

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.

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

2012-12-01

69

Geologic and Navajo Time Line  

NSDL National Science Digital Library

This lab serves to introduce students to geologic time and serves as an outline for the course through the semester. Students use a tape register and must mark out the corresponding length of each Geologic Era and Eon towards the beginning of the course. Above Western time line Navajo students construct their own time line correlating events as best as possible. As the course progresses starting from 4.6bya each week they must draw major events that occur marking correct subdivisions of time and ages ago. As fossil life gets more complex such as beginning in the Paleozoic students are must take different categories of fossils or different periods so all are doing different things but working together. (Similarly the Navajo time line builds. This time line is taped around the room---and I would have liked to paint the two time lines along the corridor of the building but Maintenance axed it.

Mayer, Margaret

70

Navajo Health Authority: Accomplishments--Future Goals.  

ERIC Educational Resources Information Center

Accomplishments of the Navajo Health Authority (NHA) since it began in 1972 are presented in synopsis form in a report of programs underway at Window Rock and Shiprock, along with NHA goals: to promote development of Navajo Health manpower, preventive medicine, health education, and native healing sciences. After a brief review of executive and…

Navajo Health Authority, Window Rock, AZ.

71

An Ethnography of the Navajo Reproductive Cycle.  

ERIC Educational Resources Information Center

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)

Wright, Anne

1982-01-01

72

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

ERIC Educational Resources Information Center

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…

Arizona Commission of Indian Affairs, Phoenix.

73

Working with Navajo Parents of Exceptional Children.  

ERIC Educational Resources Information Center

Undergraduate students at Northern Arizona University interviewed and surveyed 20 staff members at Kayenta Unified School District (KUSD) on the Navajo Reservation and 14 parents of exceptional Navajo children enrolled in KUSD. Both groups were asked to identify challenges affecting the working relationship between parents and school on a rural…

Jones, Doris; And Others

74

Navajo Art--A Way of Life.  

ERIC Educational Resources Information Center

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…

Clover, Faith

75

Navajo Educational Values and Facility Design.  

ERIC Educational Resources Information Center

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…

Dore, Christopher D.

76

Some Remarks on Navajo Geometry and Piagetian Genetic Theory.  

ERIC Educational Resources Information Center

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…

Pinxten, Rik

1991-01-01

77

Final Report - Navajo Electrification Demonstration Project - FY2004  

SciTech Connect

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.

Kenneth L. Craig, Interim General Manager

2007-03-31

78

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

Microsoft Academic Search

Tabular sandstone uranium deposits constitute the largest uranium resource type in the United States. A major point of contention has been the nature and direction of the groundwater flow. This paper presents a quantitative simulation of regional ground-water flow during uranium deposition in the Westwater Canyon Member and Jackpile Sandstone Member of the Upper Jurassic Morrison Formation in the San

Sanford

2009-01-01

79

Jurassic Park Safety Audit  

NSDL National Science Digital Library

Using the first 30 minutes of the film Jurassic Park, the student will audit it for violations of safety rules and regulations, OSHA violations, and violations of HASP's. Access to the activity required free and quick registration with ATEEC.

2007-09-18

80

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

ERIC Educational Resources Information Center

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;…

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

81

Kinaalda: The Pathway to Navajo Womanhood.  

ERIC Educational Resources Information Center

Presents a personal account of the Navajo ceremony of Kinaalda, performed when a girl reaches puberty. Describes ceremonial running, corn grinding, and grooming, and admonitions and blessings received from grandmother, elderly women of the tribe, and medicine man. (SV)

Ryan, Danita Begay

1988-01-01

82

Mineral paragenesis and textures associated with sandstone-hosted roll-front uranium deposits, NW China  

Microsoft Academic Search

We present a first paragenetic study of the Wuyier, Wuyisan, Wuyiyi and Shihongtan sandstone-hosted roll-front uranium deposits, northwest China. The mineralization is hosted by Lower–Middle Jurassic coarse- to medium-grained sandstones, which are dark-gray to black due to a mixture of ore minerals and carbonaceous debris. The sandstone is alluvial fan-braided river facies. Minerals associated with these deposits can be broadly

Maozhong Min; Jia Chen; Jinpeng Wang; Guanhui Wei; Mostafa Fayek

2005-01-01

83

Heterogeneity of eolian sandstones and enhanced oil recovery  

SciTech Connect

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.

Schenk, C.J.; Krystinik, L.F. (Geological Survey, Denver, CO (USA))

1989-09-01

84

The Navajo Uranium Mining Experience, 2003-1952  

NSDL National Science Digital Library

This bibliography, compiled by the Southwest Research and Information Center, contains resources related to Navajo uranium issues and communities affected by uranium mining impacts since the mid-1970s. Entries were selected for their relevancy to Navajo community concerns, Navajo Nation policies, and health and environmental effects of uranium development on Navajo lands. Topics for resources include articles, books, policy statements, reports, presentations, testimony, and published medical, scientific and sociological literature.

Shuey, Chris; Center, Southwest R.

85

Ichnology of Lower Jurassic beach deposits in the Shemshak Formation at Shahmirzad, southeastern Alborz Mountains, Iran  

Microsoft Academic Search

A 19 m thick package of well-sorted lowermost Jurassic (Hettangian-Lower Sinemurian?) sandstones within the Shemshak Formation\\u000a of the southeastern Alborz Mountains displays features characteristic of foreshore to upper shoreface environments such as\\u000a tabular bedding, low-angle lamination, trough cross-stratification, parting lineation, and oscillation ripples. In contrast\\u000a to most other beach successions recorded in the literature the sandstones contain a trace fossil assemblage

Franz T. Fürsich; Markus Wilmsen; Kazem Seyed-Emami

2006-01-01

86

Health Problems of the Navajo Area and Suggested Interventions.  

ERIC Educational Resources Information Center

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…

Kaltenbach, Charles

87

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

ERIC Educational Resources Information Center

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…

Atcitty, Thomas E.

88

Proposed Navajo railroad project, New Mexico  

SciTech Connect

An abstract of the draft environmental impact statement of a rail proposal to transport coal from the Burnham mine in New Mexico to southwestern power plants across Navajo lands describes the construction and design of the rail connections. The railroad, to be operated by the Consolidation Coal Company (Consol), would serve new markets that lack dependable, low-cost transportation services. Employment opportunities for Navajo workers and additional revenues will benefit the region. Rights-of-way requirements will disrupt Navajo grazing and cultivated lands as well as cultural sites. There will also be noise pollution and both water and excavation material needs for the construction. The proposal comes under several legal mandates involving water pollution, interstate commerce, rivers, and relocation assistance.

Not Available

1982-11-01

89

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

ERIC Educational Resources Information Center

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…

Lee, Lloyd L.

2008-01-01

90

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

ERIC Educational Resources Information Center

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…

Cordova, Dahlia

91

Utilising borehole image logs to interpret delta to estuarine system: A case study of the subsurface Lower Jurassic Cook Formation in the Norwegian northern North Sea  

Microsoft Academic Search

The Lower Jurassic Cook Formation forms a regressive and transgressive sandstone wedge of shallow marine reservoir sandstones. It is distributed mainly in the Norwegian sector of the northern North Sea and the formation has proven to be hydrocarbon bearing. A case study of this formation from the Tampen Spur area presents a methodology for reconstructing depositional environments in areas of

Atle Folkestad; Zbynek Veselovsky; Paul Roberts

92

Apatite fission track age of Mesozoic sandstones from Beipiao basin, eastern China: Implications for basin provenance and tectonic evolution  

Microsoft Academic Search

The apatite fission track (FT) analysis of Jurassic sandstones from the Beipiao basin in the eastern China indicates a large variation in FT age peaks. The sandstone of the Beipiao Formation has two peak ages at 178.8 and 40.0 Ma, while the sandstone of the Tuchengzi Formation has three age peaks at 152.0, 77.5 and 32.5 Ma. This implies that

YI YAN; GE LIN; YUE-JUN WANG; FENG GUO; ZI-AN LI; XIAO-MING LI; CHONGBIN ZHAO

93

Ramah Navajo Radio and Cultural Preservation  

ERIC Educational Resources Information Center

The Ramah leadership, aware of their isolation, the lack of economic opportunity, the Navajo's poor self image as a people, and the almost total absence of any sense of community, built a radio station. This study, conducted over three and a half years after the station was put into operation, is a preliminary assessment of its impact upon the…

Rada, Stephen A.

1978-01-01

94

Upper Jurassic and Lower Cretaceous sedimentary sequence, Baltimore Canyon trough, US Atlantic margin  

SciTech Connect

The extent and character of Upper Jurassic and Lower Cretaceous rock units in the Baltimore Canyon Trough are revealed by geologic data from 29 exploratory wells. These data, released to the public in 1982, have been used previously to define regional rock-stratigraphic units. In this study, four detailed stratigraphic cross sections were constructed to show rock-unit correlations based on lithology and electric logs. Thin-section photomicrographs document the mineralogic composition of these units. Most of the Upper Jurassic section consists primarily of Mic Mac gray shale and siltstone with minor amounts of very fine to medium-grained quartzarenite, red-brown shale, and lignite. This interval also contains some anomalously thick sandstones and siltstones, which are generally limited to the north and have been tentatively assigned to the Mohawk unit. These sandstones are mostly medium to coarse-grained, calcite-cemented quartzarenites. Upper Jurassic Abenaki limestone as much as 2210 ft (675 m) thick was penetrated by most of the eastern wells. The limestone is mostly wackestone to grainstone, with varying amounts of oolites and fossils. Thick-bedded sandstones characterize the Lower Cretaceous Mississauga unit. These sandstones are mostly fine to medium-grained, calcite-cemented quartzarenites. The overlying Naskapi unit consists of calcareous shale. Thick sandstone beds dominate the uppermost Logan Canyon unit, which consists mostly of fine to coarse-grained, calcite-cemented quartz arenite.

Libby-French, J.

1984-12-01

95

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

USGS Publications Warehouse

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)

Farrar, C. D.

1978-01-01

96

Electrocardiographic axis deviation in Navajo and Apache indians.  

PubMed

It has been our clinical impression that the range of the mean frontal-plane electrocardiographic QRS axis was greater than might have been anticipated in healthy Navajo and Apache Indians. To determine whether this clinical impression was correct, electrocardiograms were obtained from 146 Navajo, 144 Apache, and 159 non-Navajo non-Apache schoolchildren with normal findings on cardiovascular examinations. A mean frontal-plane QRS axis between -1 degrees and -90 degrees was present in 19 percent of the Navajo, 12 percent of the Apache, and 2 percent of the control schoolchildren. A mean frontal-plane QRS axis between +91 degrees and +180 degrees was present in 18 percent of the Navajo, 19 percent of the Apache, and 5 percent of the control schoolchildren. There is a high incidence of electrocardiographic mean frontal-plane QRS axis deviation in healthy Navajo and Apache schoolchildren. PMID:421525

Ewy, G A; Okada, R D; Marcus, F I; Goldberg, S J; Phibbs, B P

1979-01-01

97

Jurassic volcaniclastic – basaltic andesite – dolerite sequence in Tasmania: new age constraints for fossil plants from Lune River  

Microsoft Academic Search

Jurassic plants excavated from a 12 × 5 m site, at Lune River, southern Tasmania, include an araucarian tree and numerous pteridophytes, belonging to the orders Osmundales, Filicales and Bennettitales. The fossils occur in 2 – 3 m of immature volcanilithic sandstone beds. The sandstone consists primarily of clasts from granitic basement rocks underlying much of southeast Tasmania and mafic clasts containing feldspathic microliths, and primary,

K. Bromfield; C. F. Burrett; R. A. Leslie; S. Meffre

2007-01-01

98

Lung cancer among Navajo uranium miners  

SciTech Connect

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.

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

1982-04-01

99

Mask of Black God: The Pleiades in Navajo Cosmology  

ERIC Educational Resources Information Center

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…

Schulz, Teresa M.

2005-01-01

100

Mask of Black God: The Pleiades in Navajo Cosmology  

NSDL National Science Digital Library

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 observational and star map skills.

Schulz, Teresa M.

2005-10-01

101

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

ERIC Educational Resources Information Center

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…

Jackson, Dean C.

102

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

ERIC Educational Resources Information Center

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)

Barry, Tom

1979-01-01

103

Demographic and epidemiologic transition among the Navajo Indians  

Microsoft Academic Search

The theories of demographic transition and epidemiologic transition provide vehicles for the examination of Navajo fertility, mortality, and growth patterns. The Navajo population is found to be growing rapidly due to decreased mortality and fertility rates which have declined but remain twice as high as U.S. rates. Infectious diseases are now less important as a factor in mortality, but remain

David W. Broudy; Philip A. May

1983-01-01

104

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

ERIC Educational Resources Information Center

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…

Batchelder, Ann

105

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

ERIC Educational Resources Information Center

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…

Wilson, Alan; Dennison, Gene

106

75 FR 10174 - Source-Specific Federal Implementation Plan for Navajo Generating Station; Navajo Nation  

Federal Register 2010, 2011, 2012, 2013

...state air quality regulations generally did not apply to facilities on Indian reservations...Reservation, and because the Navajo Nation did not have a federally applicable tribal implementation...being recodified to 40 CFR part 49. EPA did not finalize the 1999 proposed FIP....

2010-03-05

107

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

ERIC Educational Resources Information Center

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).…

Fowler, Henry H.

2010-01-01

108

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

ERIC Educational Resources Information Center

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)

Semken, Steven C.

1992-01-01

109

The significance of dropstones in a tropical lacustrine setting, eastern Cameros Basin (Late Jurassic–Early Cretaceous, Spain)  

Microsoft Academic Search

Outsized clasts (mainly white quartzite pebbles) are found in carbonate deposits of the Enciso Group exposed on the northern border of the Cameros rift basin (Late Jurassic–Early Cretaceous, northern Spain). In the Arnedillo section, all the stones are enclosed in micrite, which was assumed deposited in littoral to open lacustrine environments, with minor inputs of deltaic sandstones. The clasts are

Stéfan Doublet; Jean-Pierre Garcia

2004-01-01

110

Jurassic Park: Adventure in Learning.  

ERIC Educational Resources Information Center

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)

Shams, Marcia; Boteler, Trina

1993-01-01

111

Sa'ah Naagháí Bik'eh Házhóón: An ethnography of Navajo educational communication practices  

Microsoft Academic Search

Navajo Community College is a bilingual\\/bicultural college on the Navajo Nation. The educational philosophy is Sa'ah Naagháí Bik'eh Hózhóón, the Diné traditional living system. This study describes and explicates Navajo educational communication practices as enacted at Navajo Community College. Ethnographic fieldwork indicates Sa'ah Naagháí Bik'eh Hózhóón in the curriculum and the classroom means incorporating the following aspects of Navajo philosophy

Charles A. Braithwaite

1997-01-01

112

JURASSIC Retrieval Processing  

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

113

Reevaluation of upper Jurassic Morrison Formation, Western Interior  

SciTech Connect

Comparison of the Brushy Basin member of the Upper Jurassic Morrison Formation in the Colorado Plateau with the Upper Jurassic-Lower Cretaceous Morrison-Cloverly sequence in the Bighorn basin, Wyoming, shows great similarities in their depositional environments and stratigraphy. The lower Brushy Basin member is a fluvial deposit composed of channel sandstones and overbank mudstones which display a great number of pedogenic features. Similar depositional setting has been observed in the Morrison Formation in the Bighorn basin, Wyoming, where pedogenic features suggest a distal floodplain setting with low-sinuosity channels cutting through. In both localities the dominant clay mineral is illite. The upper Brushy Basin member in the Colorado Plateau is composed mostly of gray and purpose mudstones rich in montmorillonite. Devitrified tuff beds and bentonite occur in certain levels throughout the unit. Pedogenic features are not conspicuously developed. The Lower Cretaceous Clovery Formation in the Bighorn basin, Wyoming, is strikingly similar in terms of lithological aspects. The depositional environment is interpreted in both localities as a playa deposit. A great variety of nodules is present such as silcretes, septaria, and silica-carbonate nodules. Radiometric dating of bentonites in central Utah revealed that the upper Brushy Basin member is Early Cretaceous in age. Field and geochemical data support these conclusions and aid the understanding of the exact nature of the depositional basin, environments, stratigraphy, and paleotectonics of the Upper Jurassic-Lower Cretaceous interval in the Western Interior.

Mantzios, C.

1989-03-01

114

Treatment of sandstone formations  

Microsoft Academic Search

A method of treating a subterranean sandstone formation with an aqueous acid solution containing hydrofluoric acid is described. The reaction rate of the acid with the formation is retarded and substantial penetration of the formation with active acid results. When the hydrofluoric acid solution contacts the sandstone formation, siliceous minerals and clay in the formation are dissolved, thereby increasing the

J. A. Knox; R. M. Lasater

1974-01-01

115

HVI and HVII mitochondrial DNA data in Apaches and Navajos.  

PubMed

Most mtDNA studies on Native Americans have concentrated on hypervariable region I (HVI) sequence data. Mitochondrial DNA haplotype data from hypervariable regions I and II (HVI and HVII) have been compiled from Apaches (N=180) and Navajos (N=146). The inclusion of HVII data increases the amount of information that can be obtained from low diversity population groups. Less mtDNA variation was observed in the Apaches and Navajos than in major population groups. The majority of the mtDNA sequences were observed more than once; only 17.8% (32/180) of the Apache sequences and 25.8% of the Navajo sequences were observed once. Most of the haplotypes in Apaches and Navajos fall into the A and B haplogroups. Although a limited number of haplogroups were observed, both sample populations exhibit sufficient variation for forensic mtDNA typing. Genetic diversity was 0.930 in the Apache sample and 0.963 in the Navajo sample. The random match probability was 7.48% in the Apache sample and 4.40% in the Navajo sample. The average number of nucleotide differences between individuals in a database is 9.0 in the Navajo sample and 7.7 in the Apache sample. The data demonstrate that mtDNA sequencing can be informative in forensic cases where Native American population data are used. PMID:12185491

Budowle, Bruce; Allard, Marc W; Fisher, Constance L; Isenberg, Alice R; Monson, Keith L; Stewart, John E B; Wilson, Mark R; Miller, Kevin W P

2002-08-01

116

An extended Nishihara model for the description of three stages of sandstone creep  

NASA Astrophysics Data System (ADS)

Many gently dipping translational rock slides have taken place in red Jurassic strata in Wanzhou which is located in the middle bank area of the Three Gorges Reservoir, China. In order to study the mechanism of these translational rock slides, conventional triaxial tests and creep tests on sandstone specimens from red Jurassic strata in Wanzhou are performed, and the rheological properties of the sandstone at accelerating creep stage are discussed. The quasi-static Nishihara model for transient and steady-state creep is modified by adding a strain-triggered inertial element in series, resulting in a phase of quadratic accelerating creep. The model fits the experimental data at all stages of creep, allowing its parameters to be inferred from the data. Finally, a sensitivity study for the analytical solution of the proposed model is carried out, showing the effects of the inertial element and stress level on the creep strain of sandstone.

Jiang, Qinghui; Qi, Yajing; Wang, Zhijian; Zhou, Chuangbing

2013-05-01

117

Uppermost Jurassic-lower cretaceous radiolarian chert from the Tanimbar Islands (Banda Arc), Indonesia  

NASA Astrophysics Data System (ADS)

This paper describes and figures Mesozoic Radiolaria from cherts in Pulau Ungar, Tanimbar Islands, eastern Indonesia. Two assemblages of Radiolaria are recognised. The lower assemblage is indicative of upper Tithonian (uppermost Jurassic) to Berriasian (lowermost Cretaceous) and the upper assemblage is of upper Valanginian to Barremian age. These are the first precise ages obtained from the Ungar Formation, a unit including sandstones with apparently good petroleum reservoir characteristics.

Jasin, Basir; Haile, Neville

118

Navajo minettes in the Cerros de las Mujeres, New Mexico  

NASA Astrophysics Data System (ADS)

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.

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

1985-06-01

119

New Late Jurassic and Middle Carboniferous Paleomagnetic Results from the Junggar Basin, NW China  

NASA Astrophysics Data System (ADS)

The Junggar Basin of northwestern China, often considered to be the southeast extremity of the Kazakhstan Block, sits in a complicated region squeezed between the Tarim Basin on the south, the Kazakhstan Block on the west, and Siberia to the northeast. New paleomagnetic data from several Late Jurassic and Middle Carboniferous rock units from the Junggar Basin suggest that the Junggar basin was close to Tarim Basin but quite far south away from Kazakhstan and Siberia. We have obtained preliminary paleomagnetic results from Late Jurassic and Middle Carboniferous rocks sampled over a large area in eastern Junggar basin. After removal of a low-temperature component that resembles both Tertiary and present field directions and fails fold test, a stable high temperature characteristic component (ChRM) remains in Late Jurassic sandstone Shishu and Xishanyao Formations, and Middle Carboniferous red sandstone and andesite Bataimayiruishan Formation. The ChRM has both normal and reversed magnetic polarities and passes local fold tests at high levels of confidence. The corresponding paleopoles place Junggar basin at paleolatitudes of 34.6 N and 19.5N in Late Jurassic and Middle Carboniferous time, respectively, suggesting that Junggar basin and its northern neighboring blocks (Kazakhstan and Siberia) have not maintained their relative positions since Middle Carboniferous.

Finn, D. R.; Zhao, X.; Li, J.

2009-12-01

120

78 FR 17743 - Navajo Nation Disaster #AZ-00026  

Federal Register 2010, 2011, 2012, 2013

...Navajo Nation (FEMA-4104- DR), dated 03/05/2013. Incident: Severe Freeze. Incident...through 01/21/2013. Effective Date: 03/05/2013. Physical Loan Application Deadline Date: 05/06/2013. Economic Injury (EIDL)...

2013-03-22

121

Consumptive Use on the Navajo Indian Irrigation Project.  

National Technical Information Service (NTIS)

Peak period and seasonal water requirements were investigated for the major crops being grown on the Navajo Indian Irrigation Project in northwestern New Mexico. Data was collected from actual production fields on the project using lysimeters, line source...

B. J. Boman

1983-01-01

122

Uranium mining and lung cancer in Navajo men  

SciTech Connect

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.

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

1984-06-07

123

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 ...

124

Frisco City sand: New Jurassic reservoir in southwest Alabama  

SciTech Connect

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.

Mann, S.D.; Mink, R.M.; Bearden, B.L. (Geological Survey of Alabama, Tuscaloosa (USA)); Schneeflock, R.D. Jr. (Paramount Petroleum Co., Inc., Jackson, MS (USA))

1989-09-01

125

Mask of the Black God The Pleiades in Navajo Cosmology  

NSDL National Science Digital Library

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, designed for an observational astronomy class or introductory astronomy class with a strong observational component, students learn about the Pleiades in Navajo cosmology while developing their observation and star map skills.

Schulz, Teresa M.

2005-01-01

126

Acute myocardial infarction among Navajo Indians, 1976-83.  

PubMed Central

We found that from 1976 through 1983 the incidence of acute myocardial infarction (AMI) diagnosed among Navajo Indians remained low (0.5 per 1,000 persons age 30 years or more), although the incidence in women appears to be climbing. Navajo AMI patients are more likely to be hypertensive and diabetic than age- and sex-matched patients with gallbladder disease. Twenty-four per cent die within one month of AMI.

Coulehan, J L; Lerner, G; Helzlsouer, K; Welty, T K; McLaughlin, J

1986-01-01

127

More frequent diagnosis of acute myocardial infarction among Navajo Indians.  

PubMed Central

In an earlier study, we failed to confirm a clinical impression that the incidence of acute myocardial infarction (AMI) was increasing in Navajo men. Extending our data collection an additional three years, through 1986, we observed that the attack rate in men more than doubled and there was a gradual increase among women. Most Navajos who sustain AMI are hypertensive (51 per cent), diabetic (50 per cent) or both (31 per cent), but few smoke cigarettes.

Klain, M; Coulehan, J L; Arena, V C; Janett, R

1988-01-01

128

Controls on the variability of net infiltration to desert sandstone  

USGS Publications Warehouse

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.

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

2007-01-01

129

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)

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.

Barnhoorn, Auke; Kisoensingh, Shailesh

2014-05-01

130

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

Code of Federal Regulations, 2011 CFR

...to this part? 161.802 Section 161.802 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Concurrence/Appeals/Amendments § 161.802 How will the Navajo...

2011-04-01

131

30 CFR 756.15 - Required amendments to the Navajo Nation's abandoned mine land plan.  

Code of Federal Regulations, 2013 CFR

...the Navajo Nation's abandoned mine land plan. 756.15 Section 756.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION...TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.15 Required amendments to the Navajo Nation's...

2013-07-01

132

25 CFR 161.101 - How will tribal laws be enforced on the Navajo Partitioned Lands?  

Code of Federal Regulations, 2011 CFR

...Partitioned Lands, including tribal laws relating to land use, environmental...responsible for enforcing tribal laws pertaining to the Navajo Partitioned...BIA will: (1) Assist in the enforcement of Navajo Nation laws; (2) Provide notice of...

2011-04-01

133

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

Microsoft Academic Search

The giant Mercosul aquifer system consists of Triassic-Jurassic eolian-fluvio-lacustrine sandstones confined by Cretaceous\\u000a basalt flows, and it covers about 1,195,500?km2 (461,583?miles2) in South America. The aquifer system encompasses all of the Paraná Basin and part of the Chaco-Paraná Basin and is one of\\u000a the world's largest. The eolian Botucatu Sandstone and its equivalents form an important part of this system.

L. M. Araújo; A. B. França; P. E. Potter

1999-01-01

134

Ages of zircons from Jurassic sediments of Bluefish River slope, NWT Canada, and the possible age of kimberlite activity on the Lena West property  

Microsoft Academic Search

This work is based on a study of 30 zircons extracted from the heavy mineral fraction of a sedimentary rock sample with anomalously high contents of well-preserved kimberlite indicator minerals (KIM). The sample was taken from the basal horizon of Jurassic?Cretaceous sandstones on the slope of Bluefish River valley. The Bluefish River, located in the Northwest Territories (Canada) north of

A. M. Agashev; S. S. Kuligin; Y. Orihashi; N. P. Pokhilenko; M. A. Vavilov; D. Clarke

2008-01-01

135

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

ERIC Educational Resources Information Center

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…

Lipps, Oscar H.

136

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

ERIC Educational Resources Information Center

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…

Federal Trade Commission, Los Angeles, CA.

137

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

Code of Federal Regulations, 2010 CFR

...Duties of Navajo Abandoned Mine Lands Reclamation...Section 401âNavajo Abandoned Mine Reclamation Fund...Liens Section 409âFilling Voids and Sealing Tunnels Section 410âDeletion...Section 412âNavajo Abandoned Mine Reclamation...

2009-07-01

138

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

Code of Federal Regulations, 2010 CFR

...Duties of Navajo Abandoned Mine Lands Reclamation...Section 401âNavajo Abandoned Mine Reclamation Fund...Liens Section 409âFilling Voids and Sealing Tunnels Section 410âDeletion...Section 412âNavajo Abandoned Mine Reclamation...

2010-07-01

139

Written reflection and drawing as assessment: A case study of a Navajo elementary science classroom  

Microsoft Academic Search

The purpose of the study was to assess if science learning could be determined by using written reflection and drawings in a science classroom of 5 th-grade Navajo students. The significance of this study was the understanding of the culture, assessments and learning of Navajo students. I studied a classroom on the Navajo reservation wherein 26 members of the class

Madeline Becker

2003-01-01

140

STEM Summer Academy on the Navajo Reservation  

NASA Astrophysics Data System (ADS)

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.

Alexander, C. J.

2012-12-01

141

Stochastic reconstruction of sandstones  

PubMed

A simulated annealing algorithm is employed to generate a stochastic model for a Berea sandstone and a Fontainebleau sandstone, with each a prescribed two-point probability function, lineal-path function, and "pore size" distribution function, respectively. We find that the temperature decrease of the annealing has to be rather quick to yield isotropic and percolating configurations. A comparison of simple morphological quantities indicates good agreement between the reconstructions and the original sandstones. Also, the mean survival time of a random walker in the pore space is reproduced with good accuracy. However, a more detailed investigation by means of local porosity theory shows that there may be significant differences of the geometrical connectivity between the reconstructed and the experimental samples. PMID:11088546

Manwart; Torquato; Hilfer

2000-07-01

142

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

ERIC Educational Resources Information Center

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…

Alvord, Lori Arviso; Van Pelt, Elizabeth Cohen

143

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

USGS Publications Warehouse

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.

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

2006-01-01

144

Sand and sandstone  

SciTech Connect

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.

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

1987-01-01

145

Triassic and Jurassic-Cretaceous deposits in the Western Chukotka: geodynamic implications, provenance studies and deformation  

NASA Astrophysics Data System (ADS)

Studied region is situated in western Chukotka, in Northeast Russia. We examine the part of Chukotka microplate, the key element in the evolution of the Amerasian basin. The Triassic of Chukotka is represented by up to 5 km of deposits. Triassic terrigeneous deposits consist of three different complexes: Lower-Middle Triassic, Upper Triassic Carnian, and Norian. All the complexes are represented by rhythmic intercalation of sandstones, siltstones and mudstones. Clastic material was carried by large rivers, possessing large reservoir on neighbouring continent. Progradation of delta system in deeper regions is observed. During the Triassic, sedimentation was represented by continental slope progradation. Petrographic study of mineral composition has established the sandstones as graywackes and lithic arenites, according to Pettijohn classification (1981). Sandstones with clasts of rock fragments of lower metamorphic grade rocks dominate at the base of Triassic deposits, sandstones with fragments of higher grade metamorphic rocks dominate in the Later Triassic deposits. This different shows that the Triassic represents an unroofing sequence sours of erosional processes that produced the clastic material eroded more deeply buried rocks through time. Detrital zircons from Triassic sedimentary rocks were collected for constain its paleogeographic links to source terranes. Zircons populations from these three samples are very similar, and youngest zircon ages show peaks at 236-255 Ma. Besides, we are dating the 9 samples for K-Ar and Rb-Sr methods. Data are similar and show 200-204 Ma, and we suppose that this isotopic data indicate the age of first stage of deformation in Chukotka's basin. The Jurassic-Cretaceous of Chukotka is represented by up to 3 km of deposits. The sedimentary complexes are enriched by organic matter, and fresh clastic materials. Fragments of shales, sometimes laminated or cleaved are their indicator constituents. Sandstones are arkosic. The chemical composition and mineral assemblages are different from Triassic sandstone. Besides, Upper Jurassic sandstones differs from Cretaceous sandstones. Our investigations indicate that Triassic, Upper Jurassic, and Lower Cretaceous sedimentary basins were related to different source provenance. In the paper will discuss the sedimentation, provenances, and geodynamic settings of Triassic and Jurassic-Cretaceous deposits. The studied part of western Chukotka is composed of variably deformed, folded and cleaved rhythmic deposits. Widely distributed and intensively deformed Triassic sequences (Tuchkova et al., 2007) and J-K units both intruded by Aptian-Albian postcollisional plutons and dikes (Katkov et al., 2010). Collisional-related fabric and subsequent granitoids are complicated by small-scale latest normal faults, in particular related to the westernmost segment of South Chukchi (Hope) basin development in Upper Cretaceous (?)-Cenozoic. Intensity of the compressional deformation of Jurassic-Cretaceous rocks is significantly less than in Triassic sequence. Work was supported by RBRR projects 11-05-00787, 11-05-00074, Scientific school # NSh-5177.2012.5, kontrakts No. 04.740.11.0190, and 01/14/20/11.

Tuchkova, M.

2012-04-01

146

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

SciTech Connect

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.

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

1995-12-31

147

Case hardening of sandstone  

NASA Astrophysics Data System (ADS)

The case-hardened crust developed on the Aztec Sandstone in the Valley of Fire, Nevada, has been characterized by a variety of techniques, including electron microscopy and infrared spectroscopy. The case-hardened crust consists mainly of host rock, with a fine-grained cement and wind-deposited kaolinite. The cement is usually calcite, but in some cases the hydrated calcium borate, colemanite, was found to be the case-hardening cement.

Conca, James L.; Rossman, George R.

1982-10-01

148

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

ERIC Educational Resources Information Center

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…

Navajo Health Authority, Window Rock, AZ.

149

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

ERIC Educational Resources Information Center

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…

Spolsky, Bernard

2002-01-01

150

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

ERIC Educational Resources Information Center

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…

Benally, AnCita; Viri, Denis

2005-01-01

151

Cultural Models of Inhalant Abuse Among Navajo Youth  

Microsoft Academic Search

Drug abuse prevention among adolescents can be more effective if it is based on an accurate knowledge of the cultural context and of how young people actually think about the drugs that are commonly used. A study was undertaken among Navajo adolescents to query their perceptions of using drugs, what the social context of their drug use is and, in

Robert T. Trotter II; Jon E. Rolf; Julie A. Baldwin

1997-01-01

152

Prevalence of Hepatitis A Virus Antibody Among Navajo School Children.  

ERIC Educational Resources Information Center

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)

Williams, Robert

1986-01-01

153

The Navajo Way: From High School to College.  

ERIC Educational Resources Information Center

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…

Noon, John

154

Decolonizing the Navajo Nation: The Lessons of the Naabaahii  

ERIC Educational Resources Information Center

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…

Lee, Lloyd L.

2011-01-01

155

The Missing Link in Navajo Indian Economic Development.  

ERIC Educational Resources Information Center

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…

Billy, Bahe

156

Of Saints and Lamanites: An Analysis of Navajo Mormonism.  

ERIC Educational Resources Information Center

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.…

Pavlik, Steve

1992-01-01

157

Eyewitness Reporting by Navajo and Mainstream-Culture Children.  

ERIC Educational Resources Information Center

This study compared cultural differences in the eyewitness reporting of Navajo and mainstream-culture third graders who were questioned 10 days after an event. Mainstream-culture children reported more information overall but the groups did not differ in accuracy. Active participation affected the amount of information reported by…

Lindstedt, D. Elise

2000-01-01

158

The Navajo Way From High School To College.  

ERIC Educational Resources Information Center

Practical and precise advice and guidelines are detailed in this volume to assist Navajo high school students in their pursuit of a college education. Part I describes considerations when choosing a college and includes a college selection worksheet. Part II outlines college admissions procedures with emphasis on A.C.T. registration and testing,…

Noon, John

159

Using Cultural Knowledge in Health Promotion: Breastfeeding among the Navajo  

Microsoft Academic Search

Although many attempts have been made to promote breastfeeding in a variety of contexts, few programs have explicitly incorporated cultural beliefs in these efforts. This article describes a breastfeeding promotion program conducted on the Navajo reservation. This program was designed to be culturally appropriate. Background information regarding beliefs and factors affecting infant feeding practices in this setting is provided, followed

Anne L. Wright; Audrey Naylor; Ruth Wester; Mark Bauer; Emily Sutcliffe

1997-01-01

160

Career Unit. The Art of Navajo Rug Weaving.  

ERIC Educational Resources Information Center

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…

Robb, Edna; And Others

161

The Derivation of Meaning in the Navajo Verb.  

ERIC Educational Resources Information Center

Lexical derivation in the Navajo verb system is described, with examples. Derivation involves four broad processes: (1) straightforward use of verbal roots and adverbial-derivational prefixes, with their base meanings; (2) extension of base root meaning, often by metaphor, to permit application to disparate concepts; (3) figurative use of…

Young, Robert W.

162

Origin of high-permeability reservoirs in Upper Minnelusa Sandstone (Permian) Powder River basin, Wyoming and Montana  

SciTech Connect

Petrographic analysis of samples from 8 Minnelusa cores from Campbell County, Wyoming, and Powder River County, Montana, reveals that high-permeability reservoirs (up to 3200 md) are the result of extensive dissolution of early precipitated gypsum or anhydrite cement. The Minnelusa reservoirs are in eolian sandstones (dune and interdune facies) that are very fine to coarse-grained, moderately to bimodally sorted quartz-arenites, subarkoses, and sublitharenites. Dune and interdune sandstones exhibit differences in detrital mineralogy that are the result of postdepositional dissolution of labile grains. The most common cements in the sandstone are anhydrite (0-30%), quartz overgrowths (0-10%), dolomite (0-10%), Kaolinite (< 5%), and illite (< 1%). Most cementation occurred during the pre-Jurassic when the sandstones were buried less than 1500 ft. The porosity network within the sandstone is a combination of primary and secondary porosity created by the dissolution of anhydrite cement. Burial history curves suggest that anhydrite dissolution occurred during the Late Jurassic to Early Cretaceous, when the top of the sandstones was still near the surface. During this time, 3 periods of uplift and erosion occurred in which meteoric waters undersaturated in calcium sulfate may have flowed through the sandstones. The distribution of the reservoirs is probably controlled by the regional structure during the periods of flushing. Dune sandstones are the most productive facies in the high-permeability reservoirs. Porosity in the dune facies averages 21% compared with an average of 9% in the interdune facies. This difference is the result of both lower depositional porosity and greater quartz and dolomite cementation in the interdune sandstones. Porosity loss due to mechanical compaction is similar for both facies.

Helmold, K.P.; Loucks, R.G.

1985-02-01

163

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

NASA Astrophysics Data System (ADS)

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.

Perri, F.

2014-03-01

164

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

USGS Publications Warehouse

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)

Eychaner, James H.

1981-01-01

165

Distribution, chemistry, isotopic composition and origin of diagenetic carbonates: Magnus Sandstone, North Sea  

SciTech Connect

Diagenetic ferroan carbonates grew in the Upper Jurassic reservoir sandstones of the Magnus oilfield in porewaters which differed in composition across the field. These porewaters remained compositionally different and stratified for at least 35 M.y. Variations in carbonate chemistry across the field are attributable to these porewater variations, which resulted from displacement of marine depositional water from the crest of the field by meteoric water during late Cimmerian subaerial exposure. Original depositional facies and detrital mineralogy strongly influenced diagenetic carbonate distribution. The objective of this paper is twofold: (1) to describe the occurrence of burial diagenetic magnesian siderite and ankerite from the Magnus Sandstone, and (2) to show that variations in the elemental and isotopic geochemistry of siderite and ankerite relate to long-lived variations in the composition of the porewaters in the sandstone during diagenesis.

Macaulay, C.I.; Haszeldine, R.S. (Univ. of Glasgow (United Kingdom)); Fallick, A.E. (Scottish Univ. Research and Reactor Centre, Glasgow (United Kingdom))

1993-01-01

166

Shelf sandstones of Twowells tongue, Dakota Sandstone, northwestern New Mexico  

Microsoft Academic Search

The Dakota Sandstone of northwestern New Mexico is composed of basal continental strata and three marine sandstone tongues, which intertongue was the Mancos Shale. The late Cenomanian Twowells tongue was the last tongue deposited in the Dakota transgressive systems tract. This tongue is most commonly gradationallly underlain by the Whitewater Arroyo shale tongue and abruptly overlain by the Rio Salado

N. R. Wolter; D. Nummedal

1988-01-01

167

Geologic map of the Winslow 30’ × 60’ quadrangle, Coconino and Navajo Counties, northern Arizona  

USGS Publications Warehouse

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.

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

2013-01-01

168

Alternative Economic Development Policies for Indian Communities. Economic Development and Navajo Social Structure.  

National Technical Information Service (NTIS)

Contents: Underinvestment--a cause of underdevelopment; Social structure of Navajo Society; Economy in a traditional community; Economic development at the tribal level; Alternative economic development programs.

L. T. Ruffing

1974-01-01

169

Metachromatic leukodystrophy in the Navajo: fallout of the American-Indian wars of the nineteenth century.  

PubMed

Our aim was to determine if the high frequency of metachromatic leukodystrophy (MLD) in Navajo Indians of the Southwestern United States is the result of a "genetic bottleneck" that occurred in the mid 19th century. Navajo Nation, Indian Health Service, and other national databases were queried for Native American patients with MLD. Pedigrees, including birth location, were established by interviewing relatives. We found that cases of MLD and their ancestors are clustered in a portion of the western Navajo Nation to which a small number of Navajo fled after armed conflict with the United States Army in the 1860s. The observed incidence of MLD on the western Navajo Nation is 1/2,520 live births, with an estimated carrier frequency of 1/25 to 1/50. No cases were observed in the eastern part of the Navajo Nation over a period of 18 years (60,000 births). The high incidence of MLD in the western Navajo Nation appears to be the result of a genetic bottleneck and probable founder effect from the mid 19th century: This mechanism may also explain the high incidence of a number of other unique, heritable disorders among the Navajo. The history of the Navajo may also be relevant to other American Indian and Alaskan Native groups that have undergone severe population reduction since the arrival of Europeans in North America. PMID:11424134

Holve, S; Hu, D; McCandless, S E

2001-07-01

170

Blood pressure and body measurements among Navajo adolescents.  

PubMed Central

WE ASSESSED THE PREVALENCE of obesity, high normal blood pressure (BP), and the relationship between BP and anthropometric measurements in a sample of Navajo adolescents. The prevalence of obesity in boys and girls was 3 times that expected in U.S. white adolescents of the same age (17.1% for boys, 15.9% for girls) using body mass index as a criterion. The prevalence of high normal BP (between the 90th and 95th percentiles) was nearly twice that expected by definition (8.7% for boys and 9.1% for girls). Although systolic blood pressure (SBP) and diastolic blood pressure (DBP) increased significantly with age for boys and not for girls, SBP and DBP increased significantly with increasing body mass for both boys and girls. Given the high prevalence of obesity and the observed association with BP, primary prevention of hypertension among the Navajo should emphasize maintaining a healthy body weight at early ages.

Gilbert, T J; Percy, C A; White, L L; Romero, F C

1996-01-01

171

Navajo Generating Station and Air Visibility Regulations: Alternatives and Impacts  

SciTech Connect

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.

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

2012-01-01

172

The Lowell Observatory Navajo-Hopi Astronomy Outreach Program  

NASA Astrophysics Data System (ADS)

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.

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

2012-08-01

173

Lowstand carbonates, highstand sandstones?  

NASA Astrophysics Data System (ADS)

The sedimentary facies, sediment dynamics and sequence architecture of modern high-energy shelves in the mid and high latitudes are largely governed by wave abrasion processes. Cool-water carbonates may form there, if the influx and/or net accretion of siliciclastics is kept at a minimum. Little dilution of the carbonate produced in situ is generally promoted by a wide "epicontinental" shelf, subdued topography of the adjacent mainland, the predominance of limestone outcrops, and an arid climate. The aforementioned requirements are rarely met, and thus will automatically lead to the formation of mixed siliciclastic-cool-water carbonates. Such an example is found in the Early to Mid-Miocene Lagos-Portimão Formation (Algarve, S-Portugal), which formed on a narrow high-energy shelf of the Atlantic Ocean that was bounded by a mountain range. The sediments of the formation consist of fossiliferous sandstone (FS), shell beds, and rhodolith blankets. Along strike, the stratification of the formation is monotonous for tens of kilometres and well exposed in coastal cliffs, whereas no outcrops of dip sections exist. The bulk skeletal composition of the sediments is typical for the warm-temperate climatic zone: various endo- and epibenthic bivalves, bryozoans, coralline algae, echinoderms, gastropods, and large foraminifers ( Heterostegina). In some very rare beds, a few isolated, not framework-forming specimens of zooxanthellate corals ( Porites, Tarbellastrea) indicate temporally elevated surface water temperatures close to the lower threshold of the coral reef ecosystem. In sandstones, the fauna is well preserved and burrowing bivalves are commonly found in life position. In limestone beds, the state of preservation of the grains ranges from intact to disintegrated and abraded specimens. We infer an accumulation of the shell beds through winnowing of fine materials (siliciclastic sand and carbonate mud) at wave abrasion depth and concentration of calcareous skeletons associated with the subsequent attraction of new epibiota in a complex shell bed. The vertical alternation of fossiliferous sandstone and shell beds, and in-phase variations of the "Photo Index" (photic biota vs. bryozoans) and "Bryozoan Index" (bivalves vs. bryozoans) is envisaged to document variations of water depth (and sea level). Sandstone units built up when wave abrasion depth (WAD) rose above the sea floor during TST (and early HST), whereas the shell beds formed during LST when the WAD for sand intersected with the sea floor. Clastic sediments were probably brought on the outer shelf during early transgression, and by longshore currents. Sea-level signatures inferred in the mixed siliciclastic-cool-water carbonate shelf setting of S-Portugal therefore significantly deviate from conventional concepts of carbonate sequence stratigraphy, which were developed for flat-topped platforms. Successful interpretations of ancient mixed sequences must therefore take into consideration the processes of production, concentration and accretion of the carbonate sediments.

Brachert, T. C.; Forst, M. H.; Pais, J. J.; Legoinha, P.; Reijmer, J. J. G.

2003-01-01

174

Teenager-, Mother-, Daughter-, Who Am I? Navajo Adolescent Mothers' Perceptions of the Maternal Role & Implications for Child Developmental Outcomes.  

ERIC Educational Resources Information Center

This study explored the meaning of motherhood among Navajo teenagers, their mothers, and community informants living in a small, rural town on a Navajo Reservation. Participating were 8 Navajo teenage mothers ranging from 16 to 19 years, 7 grandmothers (mothers of the teens) who ranged from 41 to 57 years, and 6 community informants: two teachers,…

Dalla, Rochelle L.

175

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

ERIC Educational Resources Information Center

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…

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

176

New Early Jurassic Tetrapod Assemblages Constrain Triassic-Jurassic Tetrapod Extinction Event  

Microsoft Academic Search

The discovery of the first definitively correlated earliest Jurassic (200 million years before present) tetrapod assemblage (Fundy basin, Newark Supergroup, Nova Scotia) allows reevaluation of the duration of the Triassic-Jurassic tetrapod extinction event. Present are tritheledont and mammal-like reptiles, prosauropod, theropod, and ornithischian dinosaurs, protosuchian and sphenosuchian crocodylomorphs, sphenodontids, and hybodont, semionotid, and palaeonisciform fishes. All of the families are

P. E. Olsen; N. H. Shubin; M. H. Anders

1987-01-01

177

Recreation and Tourism Potential Route No. 3-Chuska Area Navajo Reservation.  

National Technical Information Service (NTIS)

The basic purpose of this project is to recommend programs for the development of the commercial aspects of recreation and tourism in the Route no. 3 and Chuska areas of the Navajo Reservation that will improve the economic status of the Navajo people. Th...

1965-01-01

178

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

ERIC Educational Resources Information Center

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…

Lockard, Louise

179

Social Welfare Problems of the Navajo Nation; A Perceptual Study of Social Welfare Needs.  

ERIC Educational Resources Information Center

The purposes of this study were, first, to identify the ways Navajos have historically met their needs, pointing out ways in which American society has dealt with their social welfare problems, and second, to determine to what extent present day social welfare services have met these needs. The study population consisted of 112 Navajo workers from…

Roanhorse, Evelyn Sharl

180

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

PubMed

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

Dawson, Susan E; Madsen, Gary E

2011-11-01

181

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

ERIC Educational Resources Information Center

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"…

Piper, June-el, Ed.

182

By-Laws of the Parent Advisory Councils Navajo (BIA) Schools.  

ERIC Educational Resources Information Center

To promote maximum Title I services to Navajo students attending the Navajo Area Bureau of Indian Affairs Schools, by-laws for the establishment and operation of a Parent Advisory Council (PAC) have been prepared. Council objectives are to develop good liaison and communication between students' parents and the local school administration; promote…

Bureau of Indian Affairs (Dept. of Interior), Window Rock, AZ.

183

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

ERIC Educational Resources Information Center

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…

Manuelito, Kathryn D.

2006-01-01

184

Comparison of Native American Navajo Bender-Gestalt Performance with Koppitz and Sompa Norms.  

ERIC Educational Resources Information Center

Compared Bender-Gestalt performance of 452 Navajo children with 1974 Koppitz and System of Multicultural Pluralistic Assessment norms (SOMPA), and investigated the use of the Bender-Gestalt for diagnosing learning disabilities. Results suggested the Koppitz and SOMPA White norms may be useful in psychological assessment of Navajo children. (JAC)

Moore, Clay L.; Zarske, John A.

1984-01-01

185

Bilingual Education for American Indians. Vol. II--Navajo. Curriculum Bulletin 13.  

ERIC Educational Resources Information Center

Bilingual education for Navajos is the central element in changing education from an alien function to one shared and controlled by the community. A number of community-controlled educational systems have become the driving force in Navajo bilingual education, and the past three years have produced not just higher quanitity, but considerably…

Bureau of Indian Affairs (Dept. of Interior), Albuquerque, NM.

186

Norms for the Wechsler Intelligence Scale for Children--Revised for Navajo Indians.  

ERIC Educational Resources Information Center

Norms were developed for Navajo Indian students for the Wechsler Intelligence Scale for Children-Revised, by sampling 16 percent of the Navajo school population from first through eighth grade in 8 schools in McKinley County, New Mexico. The norms, based on 539 students, help to separate cultural and language differences from learning…

Tempest, Phyllis; Skipper, Betty

1988-01-01

187

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

SciTech Connect

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.

Dawson, W.C.; Callender, C.A. (Texaco, Houston, TX (United States))

1991-03-01

188

Sequence stratigraphy of the Kingak Shale (Jurassic-Lower Cretaceous), National Petroleum Reserve in Alaska  

USGS Publications Warehouse

Beaufortian strata (Jurassic-Lower Cretaceous) in the National Petroleum Reserve in Alaska (NPRA) are a focus of exploration since the 1994 discovery of the nearby Alpine oil field (>400 MMBO). These strata include the Kingak Shale, a succession of depositional sequences influenced by rift opening of the Arctic Ocean Basin. Interpretation of sequence stratigraphy and depositional facies from a regional two-dimensional seismic grid and well data allows the definition of four sequence sets that each displays unique stratal geometries and thickness trends across NPRA. A Lower to Middle Jurassic sequence set includes numerous transgressive-regressive sequences that collectively built a clastic shelf in north-central NPRA. Along the south-facing, lobate shelf margin, condensed shales in transgressive systems tracts downlap and coalesce into a basinal condensed section that is likely an important hydrocarbon source rock. An Oxfordian-Kimmeridgian sequence set, deposited during pulses of uplift on the Barrow arch, includes multiple transgressive-regressive sequences that locally contain well-winnowed, shoreface sandstones at the base of transgressive systems tracts. These shoreface sandstones and overlying shales, deposited during maximum flooding, form stratigraphic traps that are the main objective of exploration in the Alpine play in NPRA. A Valanginian sequence set includes at least two transgressive-regressive sequences that display relatively distal characteristics, suggesting high relative sea level. An important exception is the presence of a basal transgressive systems tract that locally contains shoreface sandstones of reservoir quality. A Hauterivian sequence set includes two transgressive-regressive sequences that constitute a shelf-margin wedge developed as the result of tectonic uplift along the Barrow arch during rift opening of the Arctic Ocean Basin. This sequence set displays stratal geometries suggesting incision and synsedimentary collapse of the shelf margin. ?? 2004. The American Association of Petroleum Geologists. All rights reserved.

Houseknecht, D. W.; Bird, K. J.

2004-01-01

189

Prevalence of Parkinson Disease Among the Navajo; a Preliminary Examination  

PubMed Central

BACKGROUND The prevalence of Parkinson disease (PD) varies by geographic location and ethnicity, but has never been studied among the Navajo. METHODS Period prevalence was calculated using the number of people diagnosed with PD in the Shiprock Service Unit Indian Health Service database during 1995–1999, 2000–2004, and 2005–2009 as the numerator, and the number seen for any reason as the denominator. Age-standardized rates were calculated using the 2000 US population. RESULTS During 2005–2009, 126 people were seen with PD (crude prevalence = 203.7/100,000 population). The age-adjusted rate was 335.9 (95% C. I. 277.8–394.0) overall, 438.5 (95% C.I. 336.5–540.5) in men and 259.7 (95% C.I. 192.8–326.7; p=0.004) in women. The adjusted rate increased with age: 788.8 (95% C.I. 652.0–925.7) for age 40 and above to 1964.9 (95% C.I. 1613.7–2316.1) for age 60 and above. Adjusted rates were 246.6 (95% C.I. 187.2–306.0) in 1995–1999 and 284.7 (95% C.I. 227.0–342.4) in 2000–2004. CONCLUSION Parkinson disease appears common among the Navajo. Estimates increased with age and time, and were higher in men. In-person interviews are needed to confirm these estimates, and to determine incidence, quality of care, and risk factors for PD among the Navajo.

Gordon, Paul H.; Zhao, Hongwei; Bartley, Denise; Sims, LT James G.; Begay, Mae-Gilene; Richardson, Sarah Pirio; Lewis, Johnnye; Rowland, Andrew S.

2014-01-01

190

Late Jurassic salamandroid from western Liaoning, China.  

PubMed

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

Gao, Ke-Qin; Shubin, Neil H

2012-04-10

191

Mask of the Black God: The Pleiades in Navajo Cosmology  

NSDL National Science Digital Library

This interdisciplinary case study will help students learn about celestial coordinates and constellations in the context of a Navajo legend. Learners will have the opportunity to determine celestial coordinates, locate the sun on the celestial sphere for any day of the year, and describe the location of a given constellation in relation to other prominent nearby constellations. The lesson could be used in high school or undergraduate coursework. The case study and teaching notes may be downloaded in PDF format. The site also includes a section for instructor feedback where general comments may be read and contributed.

Schulz, Teresa M.

2011-01-06

192

Irrigation management with remote sensing. [Navajo Indian Irrigation Project  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

193

Navajo Coal Combustion and Respiratory Health Near Shiprock, New Mexico  

PubMed Central

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??g/m3. This is the first time that PM2.5 has been quantified and characterized inside Navajo reservation residents' homes.

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

2010-01-01

194

The Lower Cretaceous Chouf Sandstone of Lebanon: is it a syn-rift clastic sequence?  

NASA Astrophysics Data System (ADS)

The lowermost unit of the Cretaceous succession onshore Lebanon is a widespread prominent sandstone formation traditionally known as the "Grès de Base". The Chouf Sandstone is one of the most distinctive geologic units in Lebanon and is extensively quarried as building sand. The formation commonly consists of a brown to white sandstone with associated claystones, shales, locally volcanics and lignites. Based on outcrop samples taken in the central and northern parts of Mount Lebanon the petrographical composition of the typical Chouf Sandstone is dominated by monocrystalline quartz (85-95%) indicating a well-sorted sandstone. Sedimentological observations suggest deposition of the formation was typically in fluvial, coastal plain and deltaic environments. The Chouf Sandstone is variable in thickness, ranging from a few metres to 300 m. In certain areas rapid lateral thickness changes have been reported which may reflect a paleo-topography or syn-depositional block faulting. Similar thickness variations in the underlying Upper Jurassic formations might be interpreted as the result of syn-rift normal faulting. In order to test the syn-rift nature of the Chouf Sandstone, modern high-resolution satellite data sets (with ~ 0.75 m horizontal and 4 m vertical resolution) were used to derive thickness data points for the Chouf Sandstone in NW Lebanon. One important reason to use high-resolution satellite data for onshore Lebanon is the general lack of structural measurements on the existing vintage geologic maps. In lieu of these basic data, the common surface point method was used to derive this information in a consistent manner across the study area. First results obtained by remote sensing techniques do reveal local variations in the thickness of the Chouf Sandstone, on order of tens to hundreds of meters. These isopach variations in a map-view sense are interpreted to be the result of deposition in individual extensional half-grabens in a much larger overall basin. As the overlying Lower Cretaceous neritic carbonate formations do not exhibit these thickness variations, the syn-rift character of the Chouf Sandstone appears to be a reasonable interpretation at this preliminary stage of this ongoing study.

Hatzenbichler, Georg; Bauer, Harald; Grasemann, Bernhard; Tari, Gabor; Nader, Fadi H.; Church, Jonathan; Schneider, Dave

2013-04-01

195

Discovery of Middle Jurassic mammals from Siberia  

Microsoft Academic Search

Mammal remains from the Middle Jurassic (Bathonian) Berezovsk Quarry on the south of Krasnoyarsk Territory, West Siberia, Russia are referred to Docodonta indet. (two edentulous fragmentary dentaries) and Mammalia indet. (a sin? gle?rooted tooth). The dentaries exemplify a unique combination of plesiomorphic characters found among stem mam? mals only in Docodonta and Morganucodon: well developed Meckel's groove, trough for postdentary

ALEXANDER O. AVERIANOV; ALEXEY V. LOPATIN; PAVEL P. SKUTSCHAS; NIKOLAI V. MARTYNOVICH; SERGEI V. LESHCHINSKIY; ANTON S. REZVYI; SERGEI A. KRASNOLUTSKII; ALEXEY V. FAYNGERTZ

196

Jurassic evolution of the Tien-Shan  

SciTech Connect

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.

Bebeshev, I.I. [Geological Institute, Moscow (Russian Federation)

1994-09-01

197

Discovering the "-Ologies" on the Jurassic Coast  

ERIC Educational Resources Information Center

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…

Peacock, Alan

2007-01-01

198

Jurassic and Cretaceous Geological History of Cuba  

Microsoft Academic Search

The Mesozoic rocks of Cuba are a key element in reconstructing the geological history of the Mesoamerican (Gulf of Mexico and the Caribbean) area. Four different Jurassic-Cretaceous sections are recorded in Cuba, including three from tectonostratigraphic terranes. From north to south they include the following: (1) a portion of the Mesozoic passive margin of North America, with outstanding zonality, especially

Jorge L. Cobiella-Reguera

2000-01-01

199

New Early Jurassic Tetrapod Assemblages Constrain Triassic-Jurassic Tetrapod Extinction Event  

NASA Astrophysics Data System (ADS)

The discovery of the first definitively correlated earliest Jurassic (200 million years before present) tetrapod assemblage (Fundy basin, Newark Supergroup, Nova Scotia) allows reevaluation of the duration of the Triassic-Jurassic tetrapod extinction event. Present are tritheledont and mammal-like reptiles, prosauropod, theropod, and ornithischian dinosaurs, protosuchian and sphenosuchian crocodylomorphs, sphenodontids, and hybodont, semionotid, and palaeonisciform fishes. All of the families are known from Late Triassic and Jurassic strata from elsewhere; however, pollen and spore, radiometric, and geochemical correlation indicate an early Hettangian age for these assemblages. Because all ``typical Triassic'' forms are absent from these assemblages, most Triassic-Jurassic tetrapod extinctions occurred before this time and without the introduction of new families. As was previously suggested by studies of marine invertebrates, this pattern is consistent with a global extinction event at the Triassic-Jurassic boundary. The Manicouagan impact structure of Quebec provides dates broadly compatible with the Triassic-Jurassic boundary and, following the impact theory of mass extinctions, may be implicated in the cause.

Olsen, P. E.; Shubin, N. H.; Anders, M. H.

1987-08-01

200

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

USGS Publications Warehouse

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

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

1994-01-01

201

Pulverization Within Sandstone Associated With Faulting at High Strain Rates at the Upheaval Dome Impact Structure, Utah  

NASA Astrophysics Data System (ADS)

We report an investigation of faults in porous sedimentary rocks subjected to high strain rates. We focused on lower-displacement faults cutting Navajo Sandstone within the ring syncline of Upheaval Dome impact structure in Canyonlands National Park, Utah, where high strain rate conditions are known to have occurred. Results of our field investigation revealed grains within the Navajo Sandstone were pulverized adjacent to the fault planes. Previous work has defined pulverized rock as rock that has been shattered in place with no evidence of shearing and as having a powdery texture that crumbles under slight pressure applied by hand. Pulverized rock has previously been identified in crystalline and sedimentary rocks associated with the San Andreas Fault. The diameter of individual pieces of pulverized material can be related to the specific strain rate under which pulverization occurred. We find that pulverized material collected at Upheaval Dome has an average grain size of 42 microns, and referencing the relationship derived by Grady and Kipp [1987], is therefore associated with strain rates of ~ 106 s-1. According to previous work, grain sizes of 350 to 1,100 microns have been observed in pulverized sedimentary rocks associated with dynamic fracturing along the San Andreas Fault and relate to strain rates of ~ 104 and 105 s-1. Strain rates of these magnitudes are well above the values typically associated with tectonic rates (10-11 s-1and below) and laboratory testing rates (between 10-7 s-1 and 10-5 s- 1) refining the importance of high strain-rate processes associated with faulting of porous sandstones.

Orr, W. R.; Schultz, R. A.

2008-12-01

202

Sedimentology and sandstone diagenesis of Hibernia formation in Hibernia oil field, Grand Banks of Newfoundland  

SciTech Connect

The Hibernia oil field is the largest discovery off the east coast of North America. The most important reservoir unit in the field is the Upper Jurassic-Lower Cretaceous Hibernia formation, which averages 200 m in thickness and occurs at depths between 3475 and 4200 m. On the basis of sedimentological descriptions of cores and downhole log responses, five lithofacies have been defined, and the formation has been subdivided into two lithostratigraphic units. The Main Hibernia zone is dominated by thick medium to very coarse-grained quartzarenites, interpreted as distributary channel deposits of a deltaic plain environment. The Upper Hibernia zone consists of relatively thin very fine to medium-grained quartzarenites interbedded with mudstones and siltstones. This zone is interpreted as deposits of a shallow marine delta-front environment. Porosities observed in thin section and provided by core analysis in the Hibernia sandstones range from 1 to 22%. Many sandstones with high porosities show evidence of dissolution of carbonate cement and some framework grains. This late enhancement of porosity by decarbonatization preceded main hydrocarbon migration and is a major factor in both the accumulation of large reserves and the potential producibility of the field. Lower porosities are associated mainly with well-compacted sandstones or those retaining abundant unleached carbonate cements. Time-temperature index modeling constrains the interpreted time and depth of hydrocarbon generation and accumulation in the sandstone reservoirs. 17 figures, 2 tables.

Brown, D.M.; McAlpine, K.D.; Yole, R.W.

1989-05-01

203

Trace fossil evidence from the Adigrat Sandstone for an Ordovician glaciation in Eritrea, NE Africa  

NASA Astrophysics Data System (ADS)

Trace fossils are described here from the Adigrat Sandstone formation of hitherto uncertain Palaeozoic-Mesozoic age in south-central Eritrea. The formation is subdivided into a lower unit, the Adi MaEkheno Member, and an upper informal unit, Member 2. The formation was deposited on the locally mudcracked top of the glacigenic Edaga Arbi Beds, suggesting that these two rock units were formed in a very short time interval. The Adi MaEkheno Member and the lower part of Member 2 contain trace fossils Arthrophycus alleghaniensis (Harlan), Arthrophycus ?brongniartii (Harlan), Didymaulichnus lyelli (Rouault), Palaeophycus tubularis Hall, Taenidium isp., thin winding ridges, winding ridges and furrows, simple cylinders, and 'stellate' forms. A. alleghaniensis is distinctively of Ordovician-Silurian (?Early Devonian) age. The trace fossil association belongs to the Cruziana ichnofacies that indicates a shallow marine environment between the normal and storm wave bases. The trace fossil data and stratigraphic relationships indicate that the Adigrat Sandstone formation and the Edaga Arbi Beds in Eritrea are Ordovician-Silurian in age. The Edaga Arbi Beds are correlated with other Upper Ordovician (Hirnantian) glacial units in northern Africa and the Arabian Peninsula, lending these beds the status of a marker unit in the Lower Palaeozoic stratigraphy of the Horn of Africa. The Jurassic "Adigrat Sandstone" in central-west and eastern Ethiopia cannot be correlated with the Adigrat Sandstone formation in its type area and in Eritrea.

Kumpulainen, R. A.; Uchman, A.; Woldehaimanot, B.; Kreuser, T.; Ghirmay, S.

2006-08-01

204

Melding Research on the Navajo Volcanic Field into Undergraduate Curriculum to Promote Scientific Literacy  

NSDL National Science Digital Library

David Gonzales, Fort Lewis College Summary Mafic dike in the Navajo volcanic field exposed near Newcomb, New Mexico. Details This module highlights the curricular design and outcomes of undergraduate research in ...

Gonzales, David

205

A Survey of Fertility Histories and Contraceptive Use Among a Group of Navajo Women.  

National Technical Information Service (NTIS)

The bulletin reports the results of a survey of 137 women living in the northwestern portion of the Navajo Reservation. The analysis covers fertility histories, patterns of contraceptive use, educational levels, residence patterns, and modes of communicat...

S. J. Kunitz

1976-01-01

206

Solar membrane distillation: desalination for the Navajo Nation.  

PubMed

Abstract 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/m2·d 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

Karanikola, Vasiliki; Corral, Andrea F; Mette, Patrick; Jiang, Hua; Arnoldand, Robert G; Ela, Wendell P

2014-01-01

207

Operation Sandstone: 1948. Technical report  

SciTech Connect

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.

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

1983-12-19

208

Healthy gardens/healthy lives: Navajo perceptions of growing food locally to prevent diabetes and cancer.  

PubMed

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

Lombard, Kevin A; Beresford, Shirley A A; Ornelas, India J; Topaha, Carmelita; Becenti, Tonia; Thomas, Dustin; Vela, Jaime G

2014-03-01

209

Navajo Generating Station and Clean-Energy Alternatives: Options for Renewables  

SciTech Connect

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).

Hurlbut, D. J.; Haase, S.; Turchi, C. S.; Burman, K.

2012-06-01

210

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

USGS Publications Warehouse

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).

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

1984-01-01

211

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

USGS Publications Warehouse

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.

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

1981-01-01

212

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)

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.

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

213

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)

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.

Busigny, V.; Dauphas, N.

2006-03-01

214

Jurassic hydrocarbon exploration of southern Florida  

SciTech Connect

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.

Mitchell-Tapping, H.J. [Retog, Inc., DeSoto, TX (United States)

1994-09-01

215

Skull of a Jurassic ankylosaur (Dinosauria)  

Microsoft Academic Search

The origin and early evolution of many major dinosaur groups are poorly known because specimens are rare. One of these groups, the Ankylosauria, or armour-plated dinosaurs, is best known from well-preserved specimens from the Upper Cretaceous period of Asia and North America. Here we describe a well-preserved skull of an earlier, Late Jurassic ankylosaur, which will be important in clarifying

Kenneth Carpenter; Clifford Miles; Karen Cloward

1998-01-01

216

Triassic-Jurassic atmospheric CO2 spike.  

PubMed

I question the claim by Tanner et al. that atmospheric CO2 levels remained constant across the Triassic-Jurassic boundary on the grounds of problems with stratigraphic completeness and contamination with atmospheric methane. Because methanogenic CH4 has a light isotope composition and oxidizes readily to CO2, methane-clathrate dissociation and oxidation events cannot be detected by palaeobarometers that use the carbon-isotope composition of palaeosol carbonate. PMID:11807543

Retallack, Gregory J

2002-01-24

217

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

PubMed Central

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.

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

2011-01-01

218

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

USGS Publications Warehouse

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.

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

2009-01-01

219

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

PubMed Central

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.

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

2009-01-01

220

Stratigraphy of Upper Jurassic Morrison and Lower Cretaceous Cloverly formations of Big Horn basin, northern Wyoming  

SciTech Connect

The Morrison and Cloverly Formations in the Big Horn basin of northern Wyoming and southern Montana are part of a distal edge of a westward-thickening clastic wedge of sediment deposited in an elongate intracontinental basin in the western North American craton. These formations reflect orogenic and volcanic activity in the western Cordillera during Late Jurassic and the subsequent eastward migration of volcanic centers during Early Cretaceous. The Morrison Formation (Upper Jurassic) conformably overlies the Jurassic marine Sundance Formation and consists of light olive-green, lenticular, calcareous siltstones and mudstones interbedded with white to buff or yellowish green, massive and cross laminated, calcareous quartz-arenites. The Cloverly Formation (Lower Cretaceous) consists of three members: the Pryor Conglomerate, and Little Sheep Mudstone, and the Himes; it overlies the Morrison Formation both conformably and unconformably. Both the Morrison and Cloverly Formations are characterized by high ratios of overbank fines relative to coarse channel sands. It has been assumed, but not documented by detailed sedimentologic study, that the deposits were part of an aggrading alluvial flood plain complex dotted by seasonal lakes and swamps and crossed by braided rivers. This model deviates from most modern braided systems which are characterized by rapid lateral mobility and the lack of fine-grained overbank material. The large ratio of fine-grained siltstones and mudstones to coarser grained sandstones can be explained by a number of processes, the most probable being rapid overbank aggradation as a result of a large influx of windblown volcanic material from vents to the west.

Kvale, E.P.; Vondra, C.F.

1983-08-01

221

Pore-throat sizes in sandstones, tight sandstones, and shales  

USGS Publications Warehouse

Pore-throat sizes in silidclastic rocks form a continuum from the submillimeter to the nanometer scale. That continuum is documented in this article using previously published data on the pore and pore-throat sizes of conventional reservoir rocks, tight-gas sandstones, and shales. For measures of central tendency (mean, mode, median), pore-throat sizes (diameters) are generally greater than 2 ?m in conventional reservoir rocks, range from about 2 to 0.03 ?m in tight-gas sandstones, and range from 0.1 to 0.005 ?m in shales. Hydrocarbon molecules, asphaltenes, ring structures, paraffins, and methane, form another continuum, ranging from 100 Å (0.01 ?m for asphaltenes to 3.8 A (0.00038 ?m) for methane. The pore-throat size continuum provides a useful perspective for considering (1) the emplacement of petroleum in consolidated siliciclastics and (2) fluid flow through fine-grained source rocks now being exploited as reservoirs.

Nelson, Philip H.

2009-01-01

222

Tidal influence within Pennsylvanian sandstones  

SciTech Connect

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.

Archer, A.W. (Kansas State Univ., Manhattan (United States))

1991-08-01

223

Impact Crater Identified on the Navajo Nation Near Chinle, Arizona  

NASA Astrophysics Data System (ADS)

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.

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

224

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

USGS Publications Warehouse

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

Klett, T. R.

2001-01-01

225

Late Paleozoic to Jurassic tectonic evolution of the Bogda area (northwest China): Evidence from detrital zircon U-Pb geochronology  

NASA Astrophysics Data System (ADS)

Since the Cenozoic, the Tian Shan is rejuvenated by crustal shortening related to the ongoing India-Asia collision. However, the tectonic process prior to the Cenozoic remains ambiguous, especially in the Bogda area of the eastern Tian Shan. The continuous Late Paleozoic-Mesozoic sequences in the Bogda area record abundant information about the basin-mountain interaction. U-Pb (LA-ICP-MS) dating of detrital zircons from seven sandstone samples from Permian to Jurassic was used to investigate the changes of provenance and basin-mountain interaction in the Bogda area. During the Permian, proximal and synchronous pyroclastic materials were the major source. The Late Paleozoic magmatic belt in the North Tian Shan (NTS) had gradually become one of the main sources by the Late Permian, which implies the uplift and exhumation in the NTS area. This is interpreted in terms of near-source sedimentation in basin developing in a post-orogenic extension setting. The large range of U-Pb ages of detrital zircons observed in the Early-Middle Jurassic sediments encompasses most of the available sources implying a wide drainage pattern developing on a rather flat topography. Re-emergence of the Early Permian peak in the spectrum implies that the Bogda Mountains has existed as a gentle positive relief and began to provide materials to the submountain regions. The southern Junggar Basin extended towards to the south and evolved as a passively subsiding basin from the Middle Triassic to the Middle Jurassic. However, the synchronous pyroclastic (tuff) and the exhumed late Paleozoic detrital materials from the uplifted Bogda Mountains were the major component of the Upper Jurassic sediments. Associated to the conglomerate in the Kalaza Formation, the basin-range evolution entered a compression uplift stage. The basin pattern evolution of the Bogda area is consistent with that of the southern Junggar Basin.

Tang, Wenhao; Zhang, Zhicheng; Li, Jianfeng; Li, Ke; Chen, Yan; Guo, Zhaojie

2014-06-01

226

Prevention of Haemophilus influenzae type b infections in Apache and Navajo children.  

PubMed

Prospective surveillance of Haemophilus influenzae type b (Hib) disease has been done since 1981 in two high-risk populations, White Mountain Apaches and Navajos. The attack rate in children less than 5 years of age is 5-10 times higher than in the general US population. Three vaccines were evaluated. Unconjugated Hib capsular polysaccharide produced lower antibody responses in 18- and 24-month-old Apache infants than in white infants. HbOC (Hib oligosaccharide covalently linked to the nontoxic mutant diphtheria toxin CRM197) produced low antibody responses in Navajo infants after one or two doses but induced responses similar to those in whites after three doses. The responses of 18-month-old Navajos to HbOC were lower than those of whites, but most achieved protective levels. PRP-OMP (Hib capsular polysaccharide linked to the outer membrane protein complex of Neisseria meningitidis) produced good immune responses in 2-month-old Navajo and Apache infants after a single dose. This vaccine was greater than 90% efficacious in protecting Navajo infants from Hib disease when given at 2 and 4 months of age. Even a single dose achieved a high protective efficacy. PMID:1588150

Santosham, M; Rivin, B; Wolff, M; Reid, R; Newcomer, W; Letson, G W; Almeido-Hill, J; Thompson, C; Siber, G R

1992-06-01

227

Relationship of WISC-R Factor Scores to Academic Achievement and Classroom Behaviors of Native American Navajos.  

ERIC Educational Resources Information Center

Reports data on the predictive utility of the WISC-R factor scores for Native American Navajos and examines the diagnostic utility of the FD scores as a correlate of academic achievement. Results indicate limited utility of the WISC-R factor scores in predicting academic achievement for Native American Navajos. (Author/RC)

Mishra, Shitala P.

1981-01-01

228

Using Multimedia with Navajo Children: An Effort to Alleviate Problems of Cultural Learning Style, Background of Experience, and Motivation.  

ERIC Educational Resources Information Center

Describes how IBM's "LinkWay" hypertext program was used in the Tuba City Boarding School (Navajo Reservation) to develop reading improvement programs and to allow students to develop their own productions. Notes that the program addresses the cooperative, noncompetitive nature of the Navajo learning style, and the problems of unfamiliar content…

Smith, Kenneth J.

1992-01-01

229

Concurrent and Longitudinal Effects of Ethnic Identity and Experiences of Discrimination on Psychosocial Adjustment of Navajo Adolescents  

ERIC Educational Resources Information Center

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…

Galliher, Renee V.; Jones, Matthew D.; Dahl, Angie

2011-01-01

230

A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago  

Microsoft Academic Search

Small Late Jurassic theropod dinosaurs are rare worldwide. In Europe these carnivorous dinosaurs are represented primarily by only two skeletons of Compsognathus, neither of which is well preserved. Here we describe a small new theropod dinosaur from the Late Jurassic period of Schamhaupten in southern Germany. Being exquisitely preserved and complete from the snout to the distal third of the

Ursula B. Göhlich; Luis M. Chiappe

2006-01-01

231

Sequence stratigraphy of the Jurassic of the Danish Central Graben  

Microsoft Academic Search

A sequence stratigraphic framework is established for the Jurassic of the Danish Central Graben based primarily on petrophysical log data, core sedimentology and biostratigraphic data from about 50 wells. Regional seismic lines are used to assist in the correlation of some wells and in the con- struction of isochore maps. In the Lower Jurassic (Hettangian-Pliensbachian) succession, five sequences have been

Jan Andsbjerg; Karen Dybkjær

232

Navajo birth outcomes in the Shiprock uranium mining area  

SciTech Connect

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.

Shields, L.M.; Wiese, W.H.; Skipper, B.J.; Charley, B.; Benally, L. (Navajo Community College, Shiprock, NM (United States))

1992-11-01

233

Conjugate Riedel deformation band shear zones  

Microsoft Academic Search

Our investigations have disclosed that individual Riedel shear zones may organize themselves into broadly distributed though rigorously oriented intraformational conjugate systems which may form without relationship to, or dependence upon, an underlying basement fault zone. The Riedel shear zones we mapped are zones of deformation bands, which developed as the preferred deformation mechanism in porous Navajo Sandstone (Jurassic). In the

George H Davis; Alexander P Bump; Pilar E Garc??a; Stephen G Ahlgren

2000-01-01

234

Water-Rock Interaction Simulations of Iron Oxide Mobilization and Precipitation: Implications of Cross-diffusion Reactions for Terrestrial and Mars 'Blueberry' Hematite Concretions  

Microsoft Academic Search

Modeling of how terrestrial concretions form can provide valuable insights into understanding water-rock interactions that led to the formation of hematite concretions at Meridiani Planum, Mars. Numerical simulations of iron oxide concretions in the Jurassic Navajo Sandstone of southern Utah provide physical and chemical input parameters for emulating conditions that may have prevailed on Mars. In the terrestrial example, iron

A. J. Park; M. A. Chan; W. T. Parry

2005-01-01

235

Navajo oral history of a pre-Columbian amphitheater in Chaco Canyon, New Mexico  

NASA Astrophysics Data System (ADS)

A large performance space attached to a natural amphitheater in the cliff face has recently been identified at the center of the pre-Columbian Chaco Complex in Chaco Canyon, New Mexico. This location is known in the ceremonial history of the Navajo people (Din) as Tsbiinaholtsa Yalti (Concavity in Bedrock that Speaks). Tsbiinaholtsa Yalti is a portal to the dimension of the deities and it is opened by way of tonally induced acousma. The physical manifestation of the amphitheater and its acoustical properties invoke the concepts of Tal (Chants) and Taal (Ceremonial pathway). Navajo ceremonies are called Haataal and religious practitioners Hataalii (Chanters). The origin of the tones which give power to contemporary Navajo chants may be traced to the Tsbiinaholtsa Yalti. These tones are produced vocally and are accompanied by the shell trumpet, eagle bone whistle, and reed flute (jadzoosh).

Blackhorse, Taft, Jr.; Williams, Jay S.

2002-11-01

236

Surgical fertility regulation among women on the Navajo Indian reservation, 1972-1978.  

PubMed Central

Changes in the rates of induced abortions, bilateral tubal ligations, and hysterectomies on the Navajo Indian Reservation have been examined for the years 1972-1978. While the incidence of abortions and tubal sterilizations is still considerably lower among Navajo women than among the total United States population of women, it has risen, especially among those in the prime of the reproductive cycle, i.e., ages 20-34. The rate of hysterectomy has not changed substantially. Regression analyses performed on the data indicate that the utilization of surgery for fertility regulation in women on the Navajo Reservation, unlike other surgical procedures, is not affected by access to hospitals which provide surgery. Rather measures of involvement in the wage work economy are of primary importance. Those areas of the Reservation having the highest levels of such involvement exhibit the highest rates of such surgery.

Temkin-Greener, H; Kunitz, S J; Broudy, D; Haffner, M

1981-01-01

237

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

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.

Blanchard, Paul J.

2002-01-01

238

Paleomagnetism of Jurassic carbonate rocks from Sardinia: No indication of post-Jurassic internal block rotations  

NASA Astrophysics Data System (ADS)

Several paleomagnetic studies on Carboniferous and Permian sedimentary and volcanic rocks from Sardinia and Corsica have recently demonstrated (1) the tectonic coherence between southern Corsica and northern Sardinia and (2) significant rotations between individual crustal blocks within Sardinia itself. The geodynamic significance of these rotations, however, is not clearly understood mainly because of uncertainties in defining their timing and causes. In order to contribute to these issues, a pioneering paleomagnetic study on Jurassic carbonates from the Baronie-Supramonte region of eastern-central Sardinia has been extended regionally and stratigraphically. A total of 280 oriented drill cores were taken from 44 sites of Middle and Late Jurassic age in the Nurra, Baronie-Supramonte, Barbagia-Sarcidano, and Sulcis regions. Despite generally weak remanent magnetization intensities, on the order of less than 1 mA/m, thermal and alternating field demagnetizations were successfully applied to define a characteristic remanent magnetization component in about 60% of the samples. Site mean directions show rather good agreement after correction for bedding tilt and yield Middle and Late Jurassic overall mean directions of D = 269.7° and I = 45.0° (?95 = 8.0°, k = 14, and n = 25 sites) and D = 275.5° and I = 50.7° (?95 = 7.2°, k = 45.3, and n = 10 sites). Positive regional and local fold and reversal tests demonstrate the primary character of the natural magnetic remanence, which is carried by magnetite. These results indicate only insignificant amounts (±10°) of post-Jurassic rotations within the island of Sardinia. The resulting Middle and Late Jurassic paleopoles (latitude (Lat) = 16.5°, longitude (Long) = 299.1°, dp = 6.4°, and dm = 10.1° and Lat = 23.4°, Long = 301.2°, dp = 6.5°, and dm = 9.7°), corrected for the opening of (1) the Liguro-Provençal Basin and (2) the Bay of Biscay using rotation parameters from the literature, fall near the coeval segment of the European apparent polar wander path. These results constrain the timing of large differential block rotations found in Late Carboniferous-Permian rocks to a pre-Middle Jurassic age and lead us to exclude tectonics related to the Alpine orogeny for such rotations.

Kirscher, U.; Aubele, K.; Muttoni, G.; Ronchi, A.; Bachtadse, V.

2011-12-01

239

Age spectra of detrital zircon of the Jurassic clastic rocks of the Mino-Tanba AC belt in SW Japan: Constraints to the provenance of the mid-Mesozoic trench in East Asia  

NASA Astrophysics Data System (ADS)

U-Pb ages of detrital zircon grains were determined from an upper Middle Jurassic siliceous mudstone and two lower Upper Jurassic sandstones of the Mino-Tanba belt, Southwest Japan, by Laser-ablation ICPMS. The age spectra of detrital zircon grains of the three analyzed samples show multiple age clusters: 175-198 Ma (Early Jurassic), 202-284 Ma (Permian to Triassic), 336-431 Ma (Silurian to Carboniferous), and 1691-2657 Ma (Neoarchean to Paleoproterozoic). As per the Precambrian grains, the prominent peak exists around 1800-2000 Ma in all analyzed samples. The age clusters of 175-198 Ma, 202-284 Ma, and 336-431 Ma suggest that pre-Middle Jurassic Japan has exposed older granitic batholiths. The corresponding batholiths occur in the Cathaysian part of South China block. In contrast, the absence of them in modern Japan suggests that these batholiths were totally consumed by post-Jurassic tectonic erosion. The Neoarchean to Paleoproterozoic detrital zircon grains were derived from South China, North China, or possibly both of them; nonetheless, the circumstantial geologic lines of evidence point to South China, in particular to Cathaysia, rather than North China.

Fujisaki, Wataru; Isozaki, Yukio; Maki, Kenshi; Sakata, Shuhei; Hirata, Takafumi; Maruyama, Shigenori

2014-07-01

240

Suitability of Frigg, Åre, and Sognefjord Formation sandstones (North Sea) for storage of CO2  

NASA Astrophysics Data System (ADS)

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 Åre 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 Åre 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 Åre 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.

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

2012-12-01

241

Pangaean climate during the Early Jurassic: GCM simulations and the sedimentary record of paleoclimate  

SciTech Connect

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.

Chandler, M.A. [Columbia Univ., Palisades, NY (United States)] [Columbia Univ., Palisades, NY (United States); Rind, D.; Ruedy, R. [Goddard Institute for Space Studies, New York, NY (United States)] [Goddard Institute for Space Studies, New York, NY (United States)

1992-05-01

242

Constructing Failure and Maintaining Cultural Identity: Navajo and Ute School Leavers.  

ERIC Educational Resources Information Center

A seven-year ethnographic study of Navajo and Ute youth in a border reservation community suggests the following factors in understanding why youth left school: (1) racial and economic relations in the community and school; (2) home child-rearing patterns of noninterference and early adulthood; and (3) cultural integrity and resistance. (KS)

Dehyle, Donna

1992-01-01

243

Navajo oral history of a pre-Columbian amphitheater in Chaco Canyon, New Mexico  

Microsoft Academic Search

A large performance space attached to a natural amphitheater in the cliff face has recently been identified at the center of the pre-Columbian Chaco Complex in Chaco Canyon, New Mexico. This location is known in the ceremonial history of the Navajo people (Din) as Tsbiinaholtsa Yalti (Concavity in Bedrock that Speaks). Tsbiinaholtsa Yalti is a portal to the dimension of

Taft Blackhorse Jr.; Jay S. Williams

2002-01-01

244

Recruitment and Retention of Federally Employed Physicians on the Navajo Indian Reservation.  

ERIC Educational Resources Information Center

Special difficulties surround the efforts of the Indian Health Service (IHS) to recruit and retain physicians for its extensive health care delivery systems on Indian reservations, particularly those of the Navajo. A comprehensive questionnaire survey obtained data on the background and attitudes of federal physicians practicing in each of the 8…

Brod, Rodney L.; And Others

245

Classroom Resiliency--A Comparison of Navajo Elementary Students' Perceptions of Their Classroom Environment  

ERIC Educational Resources Information Center

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…

Piechowski, Alta Begay

2011-01-01

246

Teaching Mathematics with Technology: Making a Navajo Blanket Design with Logo.  

ERIC Educational Resources Information Center

A Navajo blanket design was constructed on a bulletin board and on geoboards. Then a program was written in LOGO to construct the pattern. Both top-down and bottom-up techniques were used. Students were encouraged to make their programs more efficient by utilizing repeat and subprocedures. (GW)

Bradley, Claudette

1993-01-01

247

Life is Harder Here: The Case of the Urban Navajo Woman.  

ERIC Educational Resources Information Center

Presents data from interviews taken in the late 1970s of 22 Navajo women living in Flagstaff, Arizona. The ages of the women ranged from early 20s to mid-60s. Information gathered pertained to education, occupation, marital status, religious background, cultural background, and stress variables. (ERB)

Griffen, Joyce

1982-01-01

248

78 FR 62509 - Approval of Air Quality Implementation Plans; Navajo Nation; Regional Haze Requirements for...  

Federal Register 2010, 2011, 2012, 2013

...south of Page on Coppermine Road (Navajo Route 20), (928) 698-2805, November...Zion NP. These areas support an active tourism industry drawing over four million...accordingly had almost 20 years under the RHR to design and implement alternative...

2013-10-22

249

Qualitative Study of the Use of Traditional Healing by Asthmatic Navajo Families  

ERIC Educational Resources Information Center

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,…

Van Sickle, David; Morgan, Frank; Wright, Anne L.

2003-01-01

250

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...

251

Protein and calorie malnutrition among preschool Navajo Indian children, a follow-up1  

Microsoft Academic Search

A follow-up study was conducted on the infant and child-feeding programs to determine the prevalence of protein and calorie malnutrition among preschool Navajo Indian children. These programs were introduced on the reservation in 1968. The numbers of patients admitted to the Public Health Service Indian Hospital in Tuba City, Arizona, with deficits in weight for their chronological ages, marasmus, and

Jean Van Duzen; James P. Carter; Roger Vander Zwagg

252

Cleanup of inactive Uranium Mill Tailings Sites in the Navajo Nation  

Microsoft Academic Search

The U.S. Congress passed the Uranium Mill Tailings Radiation Control Act (UMTRCA) in 1978 to address potential and significant radiation health hazards to the public from active and inactive mill operations. Title I to the UMTRCA identified sites to be designated for remedial action. These include four uranium mill tailings remedial action (UMTRA) sites in the Navajo Nation. These sites

1994-01-01

253

Transfer of children and the importance of grandmothers among the Navajo Indians  

Microsoft Academic Search

This paper explores informal fosterage patterns in 98 cases in the Navajo Tribe. It examines the cultural basis of social support offered by grandmothers in issues of substitute parenting. The majority of children in the sample were given to mother's mother. The precipitating factors in fosterage were: inability of parents to meet the needs of rearing their young, grandmother's needs,

Dianna J. Shomaker

1989-01-01

254

Coping and Responses to Stress in Navajo Adolescents: Psychometric Properties of the Responses to Stress Questionnaire  

ERIC Educational Resources Information Center

This study tested the factor structure of coping and stress responses in Navajo adolescents and examined the reliability and validity of the Responses to Stress Questionnaire (RSQ; Connor-Smith, Compas, Wadsworth, Thomsen, & Saltzman, 2000) with this population. Confirmatory factor analyses revealed that a correlated five-factor model of stress…

Wadsworth, Martha E.; Rieckmann, Traci; Benson, Molly A.; Compas, Bruce E.

2004-01-01

255

From Break Dancing to Heavy Metal: Navajo Youth, Resistance, and Identity.  

ERIC Educational Resources Information Center

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)

Deyhle, Donna

1998-01-01

256

Educational and Institutional Services Available to Navajo and Hopi People: Observations of Student Teachers.  

ERIC Educational Resources Information Center

The personal, evaluative statements of student teachers were used to study the perceptions of newcomers to American Indian schools and communities. Respondents in this study were 90 Anglo preservice teachers from 10 universities, completing the final 17 weeks of their teacher preparation programs as full-time student teachers in Navajo and Hopi…

Mahan, James M.

257

Aerial Radiological Survey of Abandoned Uranium Mines in the Navajo Nation.  

National Technical Information Service (NTIS)

Aerial radiological surveys of forty-one geographical areas in the Navajo Nation were conducted during the period of October 1994 through October 1999. The surveys were conducted at the request of the U.S. Environmental Protection Agency (EPA) Region 9 an...

T. J. Hendricks

2001-01-01

258

Methods and Resources for the Construction and Maintenance of a Navajo Population Register.  

ERIC Educational Resources Information Center

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…

Kelly, William H.

259

Doing Something about Young Navajo Women Who Are School Dropouts. [A Project Evaluation).  

ERIC Educational Resources Information Center

This is an external evaluation of the "Career Education and High School Completion Project for Girls and Young Women" at the Crownpoint (New Mexico) Institute of Technology (CIT). The project, funded by the federal Women's Educational Equity Act Program (WEEAP), targeted primarily Navajo females age 18 and under in grades 7 through 12 who were…

Mokler, Mary M.; Hernandez, Francisca

260

Behavioral Characteristics of Gifted Navajo Students as Correlated with Intellectual Ability and Creativity.  

ERIC Educational Resources Information Center

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…

Julien, Paul Daniel; Ostertag, Bruce Andrew

261

The Goal Wheel: Adapting Navajo Philosophy and the Medicine Wheel to Work with Adolescents  

ERIC Educational Resources Information Center

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…

Garner, Holly; Bruce, Mary Alice; Stellern, John

2011-01-01

262

Educational Expectations in a Democratic Society Held by Navajo Parents and Their Children.  

ERIC Educational Resources Information Center

Navajo students have a 31% dropout rate, and it has been getting worse. Although considerable research has examined the reasons behind this dropout rate, little attention has been given to parental expectations of their children's education. Interviews with 45 parents of students attending Montezuma Creek Elementary School, a public school on the…

Parent, Sydney B.; Bunderson, Eileen D.

263

Maslow's Hierarchy of Needs and Navajo Students' Struggle for Self Esteem.  

ERIC Educational Resources Information Center

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…

Walker, Kay

1996-01-01

264

QUALITATIVE STUDY OF THE USE OF TRADITIONAL HEALING BY ASTHMATIC NAVAJO FAMILIES  

Microsoft Academic Search

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, only 29% sought traditional healing for asthma. Use of

David Van Sickle; Frank Morgan; Anne L. Wright

265

Main phytostratigraphic boundaries in the Jurassic deposits of Western Siberia  

NASA Astrophysics Data System (ADS)

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.

Mogutcheva, N. K.

2014-05-01

266

Triassic and Jurassic structural development along the Tornquist Zone, Denmark  

NASA Astrophysics Data System (ADS)

In the Danish area the old crustal weakness zone, the Tornquist Zone, was repeatedly reactivated during the Triassic and Jurassic/Early Cretaceous, causing minor dextral movements along the major boundary faults. These tectonic events were minor as compared to the tectonic events of the Late Carboniferous/Early Permian and the Late Cretaceous/Early Tertiary, although a dynamic structural and stratigraphical analysis indicate that the zone was highly active compared to the surrounding areas. During the Middle to Late Permian the area was exposed to erosion and became a peneplane. A regional Triassic subsidence produces seismic onlap towards the northeast, where the youngest Triassic sediment is found, supercropping the Precambrian basement. During mainly the Early Triassic, several of the major Early Permian faults became reactivated, probably with dextral strike-slip along the Børglum Fault. The Jurassic-Early Cretaceous subsidence became restricted primarily to the area between the two main faults in the Tornquist Zone, the Grenå-Helsingborg Fault and the Børglum Fault. This restricted basin development indicates a change in the regional stress field that seems to have come into existence during the transition between the Triassic and the Jurassic. The subsidence in the Middle Jurassic and the Late Jurassic-Early Cretaceous follows the Early Jurassic pattern with local subsidence in the Tornquist Zone, but even more restricted to the zone. The subsidence seems to have decreased in the Middle Jurassic; hereafter subsidence increased again during Late Jurassic/Early Cretaceous times. A set of small faults were generated during the Mesozoic internally in the Tornquist Zone. This fault pattern indicates a broad transfer of strike-slip/oblique-slip motion from the Grenå-Helsingborg Fault to the Børglum Fault.

Mogensen, Tommy E.

1995-12-01

267

Development of risk maps to minimize uranium exposures in the Navajo Churchrock mining district  

PubMed Central

Background Decades of improper disposal of uranium-mining wastes on the Navajo Nation has resulted in adverse human and ecological health impacts as well as socio-cultural problems. As the Navajo people become increasingly aware of the contamination problems, there is a need to develop a risk-communication strategy to properly inform tribal members of the extent and severity of the health risks. To be most effective, this strategy needs to blend accepted risk-communication techniques with Navajo perspectives such that the strategy can be used at the community level to inform culturally- and toxicologically-relevant decisions about land and water use as well as mine-waste remediation. Objective The objective of this study was to develop GIS-based thematic maps as communication tools to clearly identify high risk exposure areas and offer alternatives to minimize public and ecological health impacts. Methods Thematic maps were produced that incorporated data derived from environmental sampling and public health surveys. The maps show the location and quality of unregulated water resources and identify regulated water sources that could be used as alternatives. In addition, the maps show the location of contaminated soil and sediment areas in which disturbance of surface deposits should be avoided. Preliminary feedback was collected from an informal Navajo working group to assess the clarity and efficacy of this proposed communication method. Results The working group found the maps to be both clear and effective, and made suggestions for improvements, such as the addition of more map features. The working group predicted that once the maps are presented to the public, water hauling and soil use behaviors will change, and dialogue with chapter officials will be initiated to accelerate further risk reduction efforts. Implications Because risk communication is complicated by language barriers, lack of infrastructure, and historical mistrust of non-Navajo researchers, mapping provides an easily interpretable medium that can be objectively viewed by community members and decision makers to evaluate activities that affect toxicant exposures.

2009-01-01

268

Late Jurassic plutonism in the southwest U.S. Cordillera  

USGS Publications Warehouse

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.

Barth, A. P.; Wooden, J. L.; Howard, K. A.; Richards, J. L.

2008-01-01

269

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

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

270

Earliest Marine beds in the Jurassic sedimentary record near the Huajuapan-Petlalcingo region, southern Mexico and their paleogeographic implications  

NASA Astrophysics Data System (ADS)

A paleogeographic model of Jurassic-Cretaceous is presented, the study area is the region near Huajuapan de Leon in the Mixteca Terrane, Mexico where a sedimentary successions constituted by interlayered terrestrial and marine beds, provides evidence of transgression and regression episodes. The sediments in the study zone were deposited over a Paleozoic metamorphic basement, the Acatlan Complex. The stratigraphic features in the Middle Jurassic of the terrestrial beds indicate a depositional elements varying from alluvial fans to floodplains and channel deposits, represented by conglomerates, sandy conglomerates and sandstones. After, in the same epoch (Bajocian and Bathonian age) a transgression coming from the Pacific Ocean covered the region. A transitional zone between continental and marine sediments is situated between Tezoatlan and Petlalcingo, the actual cross section consists in the earliest marine beds: limestones interlayered with terrestrial beds. Fossil contents in this beds indicate an age between the Oxfordian and the Tithonian. During this period of transgression the paleogeography was dominated by a small bay with shallow waters connected in the south with the Pacific Ocean, represented principally by limestone and dolomite units. At the end of the transgression, volcanic episodes occurred and the land emerged again. The sedimentary beds were later affected by tectonic activity that produced a normal fault near Zapotitlan, putting the metamorphic basement in contact with the sedimentary sequence.

Contla, D.

2008-12-01

271

Lower-Middle Jurassic paleomagnetic data from the Mae Sot area (Thailand): Paleogeographic evolution and deformation history of Southeastern Asia  

NASA Astrophysics Data System (ADS)

We have carried out a paleomagnetic study (12 sites, 85 samples) of Early-Middle Jurassic limestones and sandstones from the Mae Sot area of western Thailand. This area is part of the Shan-Thai-Malay (STM) block, and its geological characteristics have led some authors to suggest a Late Jurassic accretion of this region against the rest of Indochina along the Changning-Menglian zone, the latter sometimes being interpreted as a Mesozoic suture. The high-temperature (or high-coercivity) component isolated yields a paleodirection at D = 359.8 °, I = 31.4 ° (? 95 = 5.0 °). The primary nature of the magnetization acquisition is ascertained at a site with reversed polarity and a positive fold test (at the 95% confidence level). Comparison of the Mae Sot paleolatitude and another one from the STM with those recently published for the Simao and Khorat blocks show no significant difference at the 95% level, showing that the STM was situated close to, or had already accreted with, the Simao or Khorat blocks in the Early-Middle Jurassic. Comparison of the latitudes from these blocks with those from China indicates a relative southward motion of 8 ± 4° of Indochina as a single entity relative to China. Most rotations of these regions relative to China are found to be clockwise (between 14 and 75°). These rotations, and most prominently the 1200 ± 500 km post-Cretaceous left-lateral motion inferred for the Red River Fault, provide quantitative estimates of the large amount of extrusion of Indochina with respect to the rest of Asia.

Yang, Z. Y.; Besse, J.; Sutheetorn, V.; Bassoullet, J. P.; Fontaine, H.; Buffetaut, E.

1995-12-01

272

Upper Jurassic and Lower Cretaceous facies relationships in a passive margin basin, western North Atlantic  

SciTech Connect

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.

Prather, B.E.

1988-02-01

273

Paleomagnetism of Jurassic volcanic rocks in southeastern Arizona and North American Jurassic apparent polar wander  

SciTech Connect

The Corral Canyon sequence in the Patagonia Mountains is a 650 meter thick homoclinal sequence consisting of interbedded volcaniclastic red-beds, welded ash-flow tuff, and lavas. Rb/Sr isotopic analysis of eight whole rock tuff samples yields an isochron age of 171 +/- 3 Ma. Welded tuffs in the Corral Canyon sequence possess a stable, primary magnetization carried in both magnetite and hematite that defines a paleomagnetic pole at 61.8/sup 0/N, 116.0/sup 0/E. Paleomagnetic study of the Canelo Hills volcanics welded tuff member also yields a stable, primary magnetization throughout a stratigraphic thickness of 600 meters. Various aspects of the paleomagnetic data indicate that discordance of the Canelo Hills volcanics pole is probably due to acquisition of remanent magnetization during a period of non-dipole behavior of the geomagnetic field. Dispersion of paleomagnetic directions suggests that the welded tuff member represents at most two cooling units and can be interpreted as a caldera-fill sequence. A revised Jurassic APW path differs significantly from available paths and has important implications for North American plate motion and paleolatitude. The spatio-temporal progression of reliable Jurassic paleopoles, in conjunction with Triassic and Early Cretaceous poles, is well described by paleomagnetic Euler pole analysis. The APW path is divided into three tracks, separated by two cusps. These cusps represent changes in the direction of North American absolute plate motion and can be correlated with global plate motion and intraplate deformation events at approximately 200-210 Ma and 150 Ma. Finally, the APW path presented herein predicts more southerly Late Triassic and Jurassic paleolatitudes for North America than have been suggested by previous authors.

May, S.R.

1985-01-01

274

NIOSH Health Hazard Evaluation Report: HETA No. 2004-0014-2929, Navajo Agricultural Products Industry, Farmington, New Mexico.  

National Technical Information Service (NTIS)

On October 1, 2003, the National Institute for Occupational Safety and Health (NIOSH) received a management request to conduct a health hazard evaluation (HHE) at Navajo Agricultural Products Industry (NAPI), in Farmington, New Mexico. The request was to ...

2004-01-01

275

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

Code of Federal Regulations, 2011 CFR

...posted at the tribal community building, U.S. Post Office, announced on local radio station, and/or published in the local newspaper nearest to the permitted Navajo Partitioned Lands where activities are...

2011-04-01

276

Quartz cement in sandstones: a review  

NASA Astrophysics Data System (ADS)

Quartz cement as syntaxial overgrowths is one of the two most abundant cements in sandstones. The main factors that control the amount of quartz cement in sandstones are: framework composition; residence time in the "silica mobility window"; and fluid composition, flow volume and pathways. Thus, the type of sedimentary basin in which a sand was deposited strongly controls the cementation process. Sandstones of rift basins (arkoses) and collision-margin basins (litharenites) generally have only a few percent quartz cement; quartzarenites and other quartzose sandstones of intracratonic, foreland and passive-margin basins have the most quartz cement. Clay and other mineral coatings on detrital quartz grains and entrapment of hydrocarbons in pores retard or prevent cementation by quartz, whereas extremely permeable sands that serve as major fluid conduits tend to sequester the greatest amounts of quartz cement. In rapidly subsiding basins, like the Gulf Coast and North Sea basins, most quartz cement is precipitated by cooling, ascending formation water at burial depths of several kilometers where temperatures range from 60° to 100° C. Cementation proceeds over millions of years, often under changing fluid compositions and temperatures. Sandstones with more than 10% imported quartz cement pose special problems of fluid flux and silica transport. If silica is transported entirely as H 4SiO 4, convective recycling of formation water seems to be essential to explain the volume of cement present in most sandstones. Precipitation from single-cycle, upward-migrating formation water is adequate to provide the volume of cement only if significant volumes of silica are transported in unidentified complexes. Modeling suggests that quartz cementation of sandstones in intracratonic basins is effected by advecting meteoric water, although independent petrographic, isotopic or fluid inclusion data are lacking. Silica for quartz cement comes from both shale and sandstone beds within the depositional basin, including possibly deeply buried rocks undergoing low-grade metamorphism, but the relative importance of potential sources remains controversial and likely differs for different formations. The most likely important silica sources within unmetamorphosed shales include clay transformation (chiefly illitization of smectite), dissolution/pressure solution of detrital grains, and dissolution of opal skeletal grains; the most likely important sources of silica within unmetamorphosed sandstones include pressure solution of detrital quartz grains at grain contacts and at stylolites, feldspar alteration/dissolution, and perhaps carbonate replacement of silicate minerals and the margins of some quartz grains. Silica released by pressure solution in many sandstones post-dates the episode of cementation by quartz; thus, this silica must migrate and cement shallower sandstones in the basin or escape altogether. Some quartz-cemented sandstones are separated vertically from potential silica source beds by a kilometer or more, requiring silica transport over long distances. The similarity of diagenetic sequences in sandstones of different composition and ages apparently is the result of the normal temperature and time-dependent maturation of sediments, organic matter and pore fluids during burial in sedimentary basins. Silica that forms overgrowths is released by one or more diagenetic processes that apparently are controlled by temperature and time. Most cementation by quartz takes place when sandstone beds were in the silica mobility window specific to a particular sedimentary basin. Important secondary controls are introduced by compartmentalized domains produced by faults (e.g., North Sea) or overpressure boundaries (e.g., Gulf Coast Tertiary). Shallow meteoric water precipitates only small amounts of silica cement (generally less than 5% in most fluvial and colian sandstones), except in certain soils and at water tables in high-flux sand aquifers. Soil silcretes are chiefly cemented by opal and microcrystalline quartz, whereas water-tab

McBride, Earle F.

277

A Giant Pliosaurid Skull from the Late Jurassic of England  

PubMed Central

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).

Benson, Roger B. J.; Evans, Mark; Smith, Adam S.; Sassoon, Judyth; Moore-Faye, Scott; Ketchum, Hilary F.; Forrest, Richard

2013-01-01

278

The role of true polar wander on the Jurassic palaeoclimate  

NASA Astrophysics Data System (ADS)

From the Late Carboniferous until the Middle Jurassic, continents were assembled in a quasi-rigid supercontinent called Pangea. The first palaeomagnetic data of South America indicated that the continent remained stationary in similar present-day latitudes during most of the Mesozoic and even the Palaeozoic. However, new palaeomagnetic data suggest that such a scenario is not likely, at least for the Jurassic. In order to test the stationary versus the dynamic-continent model, we studied the Jurassic apparent polar wander paths of the major continents, that is, Eurasia, Africa and North America that all in all show the same shape and chronology of the tracks with respect to those from South America. We thus present a master path that could be useful for the Jurassic Pangea. One of the most remarkable features observed in the path is the change in pole positions at ~197 Ma (Early Jurassic), which denotes the cessation of the counter-clockwise rotation of Pangea and commencement of a clockwise rotation that brought about changes in palaeolatitude and orientation until the end of the Early Jurassic (185 Ma). Here, we analyse a number of phenomena that could have triggered the polar shift between 197 and 185 Ma and conclude that true polar wander is the most likely. In order to do this, we used Morgan's (Tectonophysics 94:123-139, 1983) grid of hotspots and performed "absolute" palaeogeographical reconstructions of Pangea for the Late Triassic and Jurassic. The palaeolatitudes changes that we observe from our palaeomagnetic data are very well sustained by diverse palaeoclimatic proxies derived from geological and palaeoecological data at this time of both the southern and northern hemispheres.

Iglesia Llanos, María Paula; Prezzi, Claudia Beatriz

2013-04-01

279

"Sydney sandstone": Heritage Stone from Australia  

NASA Astrophysics Data System (ADS)

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.

Cooper, Barry; Kramar, Sabina

2014-05-01

280

Geologic study and engineering review of Jurassic Smackover Formation of Thomasville field, Rankin County, Mississippi  

SciTech Connect

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.

Shew, R.D.; Garner, M.M.

1986-09-01

281

Petroleum geology of the Upper Jurassic and Lower Cretaceous, Baltimore Canyon trough, western North Atlantic Ocean  

SciTech Connect

Numerous hydrocarbon shows, including a noncommercial gas and gas-condensate accumulation, occur in the Baltimore Canyon Trough within sandstone units deposited in prograding coastal-plain and transitional-marine environments located updip of an Oxfordian/Kimmeridgian carbonate shelf edge. The coastal-plain and transitional-marine facies are overlain by a fine-grained deltaic complex dominated by delta-plain shales which collectively form a regionally extensive top seal unit. Wells drilled seaward of the continental shelf edge ( > 1,500 m water depth) tested large structural/stratigraphic closures along the downdip termination of the Upper Jurassic/Lower Cretaceous carbonate shelf edge but encountered no significant hydrocarbon shows. Reservoir rocks in these wells consist of (1) oolite grain-stone, which was deposited within a shoal-water complex located at the Aptian shelf edge, and (2) coral-stromatoporoid grainstone and boundstone. Structural closures having reservoir and top seals are present in both updip and downdip trends. hydrocarbon shows in wells along the shelf interior trend indicate the presence of mature source beds, at least locally. The absence of hydrocarbon shows in downdip carbonate reservoirs and around the Schlee Dome, however, suggests charge/migration mechanisms within the fetch areas of these objectives have failed. Continued development of play concepts in the Baltimore Canyon Trough, therefore, requires identification and mapping of potential source-rock intervals and construction of hydrocarbon expulsion models to time hydrocarbon generation relative to trap formation.

Prather, B.E. (Shell Offshore Inc., New Orleans, LA (United States))

1991-02-01

282

Sedimentological evolution, diagenesis and hydrocarbon potentiality of late Jurassic carbonates, Eastern Region, Yemen Arab Republic  

SciTech Connect

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.

El-anbaawy, M.I.H.; Al-thour, K.A. (Dept. of Geology, Faculty of Science, Cairo Univ., Giza (EG))

1989-01-01

283

Early Jurassic black shales: Global anoxia or regional "Dead Zones"?  

NASA Astrophysics Data System (ADS)

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.

van de Schootbrugge, B.; Payne, J.; Wignall, P.

2012-12-01

284

Supraregional seismites in Triassic - Jurassic boundary strata  

NASA Astrophysics Data System (ADS)

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 ?13C 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.

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

285

The “van Zijl” Jurassic geomagnetic reversal revisited  

NASA Astrophysics Data System (ADS)

We have collected two new detailed records of what could be the second oldest well documented reversal, the "van Zijl" Jurassic (˜180 Ma) reversal recorded in the thick basalt sequences of the Karoo large igneous province in Lesotho and South Africa. Sections yielded 10 and 8 independent transitional paleomagnetic directions respectively over two continuous 130 m and 160 m sequences. The corresponding VGP reversing paths share a number of consistent features and are integrated with a third record at Bushmen's Pass from Prévot et al. (2003) to yield a single reversal path with: 1- a large directional jump with no transitional poles between 45°S and 45°N in the first, main phase of the reversal, 2- a large elongated loop (multiple hairpin) to the SE with poles going down to ˜20° latitudes in the second phase of the reversal, and 3- a rebound before finally settling in normal polarity. We have measured relative paleo-intensities on a set of carefully selected samples. Intensity was low prior to the directional changes and recovery to the following normal polarity was progressive. Transitional intensity is 80 to 90% lower than full polarity values. There is no significant increase in intensity at the time of transitional directional clusters. Our results are consistent with a weak non-dipolar reversing field, with faster and larger directional secular variation as the equator is crossed by VGPs. They tend to vindicate the notion of a short duration of the directional reversal, though one cannot draw global conclusions from a record limited to essentially a single location.

Moulin, Maud; Courtillot, Vincent; Fluteau, FréDéRic; Valet, Jean-Pierre

2012-03-01

286

Multistage variable probability forest volume inventory. [Defiance Unit of the Navajo Nation in Arizona and Colorado  

NASA Technical Reports Server (NTRS)

The net board foot volume (Scribner log rule) of the standing Ponderosa pine timber on the Defiance Unit of the Navajo Nation's forested land was estimated using a multistage forest volume inventory scheme with variable sample selection probabilities. The inventory designed to accomplish this task required that both LANDSAT MSS digital data and aircraft acquired data be used to locate one acre ground splits, which were subsequently visited by ground teams conducting detailed tree measurements using an optical dendrometer. The dendrometer measurements were then punched on computer input cards and were entered in a computer program developed by the U.S. Forest Service. The resulting individual tree volume estimates were then expanded through the use of a statistically defined equation to produce the volume estimate for the entire area which includes 192,026 acres and is approximately a 44% the total forested area of the Navajo Nation.

Anderson, J. E. (principal investigator)

1979-01-01

287

Genetic diversity in and conservation strategy considerations for Navajo Churro sheep.  

PubMed

The objectives of this study were to 1) evaluate the genetic diversity of Navajo-Churro sheep using pedigree information; 2) examine the distribution of the Navajo-Churro population; and 3) evaluate the effect of breeder dynamics on genetic conservation of the breed. Pedigree data and breeder information (city and state) were obtained from the Navajo-Churro Sheep Breed Association. Inbreeding coefficients were calculated for each individual animal using pedigree information. A geographic information system program was used to divide the United States into four regions and overlay breeder locations, flock size, and flock inbreeding level. The small correlation between level of inbreeding and flock size (r = -0.07, P = 0.07) indicated that inbreeding levels are not different across flock sizes. The mean flock inbreeding levels ranged from 0 to 11% across regions. The level of inbreeding did not differ among regions (P = 0.15), except for Region 4 (Kansas and Missouri; P = 0.001). The number of breeders registering sheep averaged 34 per year. Most of the breeders were transient, with only eight breeders maintaining ownership for more than 7 yr. Average inbreeding level for 2000 was found to be 1.2%, with a linear increase in inbreeding of 0.1%/yr over the period studied, suggesting a minimal loss of genetic diversity for the Navajo-Churro. However, given the relatively small effective population size (92) and the transient nature of the breeders, development of an ex situ cryo-preserved germplasm bank may be the best long-term strategy for maintaining this breed's genetic diversity. PMID:15484940

Maiwashe, A N; Blackburn, H D

2004-10-01

288

Qualitative Investigation of Factors Contributing to Effective Nutrition Education for Navajo Families  

Microsoft Academic Search

Objectives Obesity rates in American Indian and Alaskan Native children are a major health threat, yet effective ways to address this\\u000a remain elusive. Building on an earlier dietary assessment of Navajo Head Start families which indicated a gap in parental\\u000a nutrition awareness despite a strong program emphasis, the aim of this project was to identify culturally relevant nutrition\\u000a education strategies

Leslie Cunningham-Sabo; Mark Bauer; Shirley Pareo; Shirleen Phillips-Benally; Julia Roanhorse; Linda Garcia

2008-01-01

289

Written reflection and drawing as assessment: A case study of a Navajo elementary science classroom  

NASA Astrophysics Data System (ADS)

The purpose of the study was to assess if science learning could be determined by using written reflection and drawings in a science classroom of 5 th-grade Navajo students. The significance of this study was the understanding of the culture, assessments and learning of Navajo students. I studied a classroom on the Navajo reservation wherein 26 members of the class took part in science instruction complemented by using writing and drawing which were used as their assessments. The perceptions of the 8 students who were interviewed represent the case. In the study I profiled the 8 participants. Their culture, language, and views on assessment and learning were documented by their words. Their responses described their learning experiences. Assessments were seen as frustrating and limiting expression of what was known and damaging when not contributed to learning. Students explained that drawing enabled them to remember along with provoking vocabulary development. Student cultural knowledge was documented as valuable background experience contributing to learning within the classroom. Students viewed science as needing to be useful in their culture. Finally, they were also very candid that their teachers must first get to know them for meaningful learning to begin. Learning for students was reinforced through writing and drawing the lesson's activities. Further concept development was assisted utilizing metacognition and creative problem solving techniques of elaboration and fluency applied to the writing and drawings. Based on the findings of this study, recommendations were made for use of holistic means of assessing Navajo children in science where preferred learning styles along with cultural background need to be included in assessment protocols. Using new and better assessment techniques can directly impact how students document their learning as well as reveal how they acquire new knowledge.

Becker, Madeline

290

Petrographic and geochemical characterization of the Triassic and Jurassic magmatic and volcanic rocks of southeastern Ecuador  

NASA Astrophysics Data System (ADS)

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.

Villares, Fabián; Eguez, Arturo; Yanez, Ernesto

2014-05-01

291

Jurassic faults of southwest Alabama and offshore areas  

SciTech Connect

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.

Mink, R.M.; Tew, B.H.; Bearden, B.L.; Mancini, E.A. (Geological Survey of Alabama, Tuscaloosa (United States))

1991-03-01

292

Chemistry and anelasticity in dehydrated sandstone  

NASA Astrophysics Data System (ADS)

Preliminary acoustic measurements of a dehydrated sample of Berea sandstone indicated a dramatic change in elastic and anelastic properties near 45C. With an improved temperature control system we have characterized the change, a softening of the modulus and an increase in dissipation, in detail. We have attempted to fit a finite-element model of a silica grain-bond network to the data and discuss ideas for the connection between water content and nonlinearity. Berea is a complex sandstone with several components beyond the silica frame, so in order to simplify the sample, we are working with a very nonlinear Fontainebleau sandstone and we present new data from both Nonlinear Resonant Ultrasound Spectroscopy (NRUS) and Dynamic Acoustic Elastic Testing on a dehydrated 99.5% silica rock.

Darling, T. W.; Miller, R. A.

2012-12-01

293

Dakota sandstone facies, western Oklahoma panhandle  

SciTech Connect

The Cretaceous Dakota Sandstone in Cimarron County comprised three sandstone units and intervening mudrocks; it overlies the Kiowa Shale Member of the Purgatoire Formation. Deposits include shoreface, beach (foreshore) and dune, estuarine and tidal channel, marine marginal bay and swamp/marsh in a generally progradational sequences associated with marine regression in the Western Interior. The shoreface sand, characterized by ripple lamination, bioturbation and the trace fossils Teichichnus and Thalassinoides, is fine-grained, 5-10 m (15-30 ft) thick and grades into the underlying Kiowa Shale. Beach and associated dune deposits are 2-5 m (6-16 ft) thick, medium to fine-grained, medium to thick-bedded, tabular-planar cross-bedded, and lenticular; cross-bed paleocurrent headings are northeasterly and northwesterly. Estuarine channel deposits are 3-5 m (10 to 16 ft) thick, trough to tabular-planar cross-bedded, and medium to coarse-grained with local conglomerate overlying the scoured base which commonly cuts into the Kiowa Shale or overlying shoreface sandstone; rip-up clasts and wood pieces are common but trace fossils are rare; southeasterly and southwesterly paleocurrents predominate. Tidal channel deposits are thinner (up to 2 m of 6 ft) and finer grained (medium to fine-grained) that the estuarine channel deposits; they occur within fine-grained sandstone and mudrock sequences, are trough cross-bedded, and commonly contain trace fossils (e.g., Skolithos) and wood fragments. Marine marginal (tidal flat or bay.) deposits comprise fine-grained sandstone, siltstone and interbedded shale, that are 1-3m (3-10 ft) thick with abundant burrows, small ripple marks, and parallel lamination. These grade into the fine to very fine-grained sandstones, siltstones, shales, and coals of the swamp/marsh deposits that are 1-5m (3-16 ft) thick and contain ripple marks, burrows, other trace fossils, and parallel lamination.

Atalik, E.; Mansfield, C.F.

1984-04-01

294

The "van Zijl" Jurassic geomagnetic reversal revisited  

NASA Astrophysics Data System (ADS)

In 1962, van Zijl and colleagues published the first record of one of the oldest reversals available in some detail. This was a Jurassic reversal recorded in the basaltic sequence of the Lesotho, part of the Karoo large igneous province. In 2003, Prévot and colleagues provided a second more accurate record (Bushmen's Pass section - BP). We have recently obtained two other detailed records from two sections (Naude's Nek NN and Oxbow-Moteng Pass OM). The reversal is therefore now recorded in some detail in three sections which are up to 200km away from each other (the age being at ~180Ma). The reversal is recorded as 23 transitional directions over 130m in NN. When lava flows having recorded the (statistically) same direction to within a few degrees, which likely belong to the same cooling unit, are regrouped (directional groups or DG), we are left with 10 independent directions. There are 13 transitional directions over 160m in OM, and 8 distinct, independent directions. And in the BP section, there are 35 transitional directions over 200m, and 21 independent directions. The three records are remarkably similar and at the same time complementary. They can be used to retrace the VGP reversal path in a unique and robust way. Directions display 4 strong clusters which are interpreted as times of slow secular variation and/or fast extrusion rate of the lava. The path jumps from transitional reversed to transitional normal directions with no intermediate directions between 30°S and 30°N (once the path has been restored to proper geographical coordinates applicable to the ~180Ma reconstruction of the continents). We have applied several techniques to determine the evolution of relative paleo-intensities during the reversal; all these methods converge to the same conclusion, with intensities lower by a factor close to 10 between the core of the reversal and the time when full normal polarity has been regained, with intermediate intensities just before and after the core of the reversal. These observations are consistent with fast and large secular variation at a time when field intensity was the weakest and field geometry the least dipolar. The question which remains is how complete is this record? At the same time, the fact that it has been recorded in such a consistent way in three very remote sections would argue in favor of a positive answer, though the large extent and volume of Karoo cooling units may argue to the contrary...

Courtillot, V.; Moulin, M.; fluteau, F.; Valet, J. M.

2011-12-01

295

Geodynamic Implications of Jurassic Ophiolites Associated with Island-Arc Volcanics, South Apuseni Mountains, Western Romania  

Microsoft Academic Search

The South Apuseni Mountains are located in the inner zone of the Carpathian belt. This area is characterized by a complex assemblage of nappes, in which Jurassic igneous associations are well represented. New geological and geochemical data on these igneous associations document the occurrence of Middle Jurassic ophiolites overlain by Late Jurassic calc-alkaline volcanic rocks.The ophiolite sequence is characterized by:

Valerio Bortolotti; Michele Marroni; Ionel Nicolae; Luca Pandolfi; Gianfranco Principi; Emilio Saccani

2002-01-01

296

Ch'al Dinek'ehji saad bee'al'ini bini'doonish: dadiits'a'igii doo dabizhi'igii (Frog: Navajo Languages Workbook. Sounds and Symbols).  

ERIC Educational Resources Information Center

Part of the first book series of "Ch'al," the word workbook written in the Navajo language provides supplementary activities to the reading program. Illustrations are in reference to the 11 sound/symbol associations in the Navajo language introduced in the reader-workbook. Illustrated objects are captioned in the Navajo language using diacritical…

Benally, Louise; And Others

297

Charters, Constitutions and By-Laws of the Indian Tribes of North America; Part IV: The Southwest (Navajo--Zuni). Occasional Publications in Anthropology Ethnology Series No. 5.  

ERIC Educational Resources Information Center

Part IV of a series of publications consisting of American Indian tribal governmental documents, this volume includes charters, constitutions, articles of association, and by-laws of Indian tribes of New Mexico and Arizona. Documents are included relative to the Navajo Tribe of Arizona and New Mexico; the Eastern Navajo Council--New Mexico; the…

Fay, George E., Comp.

298

Memorandum on possibility of developing ground water for irrigation along Toc Chinlin Wash near Emmanuel Mission, Navajo Indian Reservation, Apache County, Arizona  

USGS Publications Warehouse

On November 21, 1949, the writers accompanied Mr. Chester Wilson of the Navajo Service Water Supply Office to Emmanuel Mission, Arizona, to investigate the adequacy of ground-water supplies adequate for irrigation along Toc Chinlin Wash. The investigation was made as part of the ground-water studies of the Geological Survey on the Navajo Indiana Reservation.

Whitcomb, H. A.; Repenning, C. A.

1950-01-01

299

He Will Lift Up His Head: A Report to the Developmental Disabilities Office on the Situation of Handicapped Navajos and the Implications Thereof for All Native Americans.  

ERIC Educational Resources Information Center

Issues involved in education of handicapped Navajo children are examined. Background sections contrast the history of treatment for the handicapped in America with the treatment received by handicapped Navajos. Unemployment, substandard housing, lack of accessibility within the reservation, overpopulation, language barriers, and the relationship…

Haskins, James S.; Stifle, J. M.

300

The Effects of Power Production and Strip Mining on Local Navajo Populations. Lake Powell Research Project Bulletin Number 22, June 1976.  

ERIC Educational Resources Information Center

In an effort to evaluate the impact of the 1972-73 Navajo Generating Station at Page, Arizona and the strip mine at Black Mesa on the Navajo Reservation, areas adjacent to each of these operations were surveyed (N=134 and 60 respectively) and compared with two control populations (N=60 from the rural area of Red Lake and 58 from the wagework area…

Callaway, Donald G.; And Others

301

Chamosite: critical ingredient in diagenetic differentiation of sandstone reservoirs  

Microsoft Academic Search

Chamosite is a common constituent in several productive Pennsylvanian sandstones such as the Spiro and Sells sandstones in the Arkoma basin and Springer sandstones in the Anadarko basin. Chamosite is a penecontemporaneous to early diagenetic mineral that occurs in several distinct morphologies, including coated grains comprised of concentric laminae around detrital nuclei, granules\\/nodules, thick pore coatings, and pseudomorphous replacement of

Z. Al-Shaieb; M. Lynch

1989-01-01

302

Extraction of uranium from carbonaceous sandstone materials  

Microsoft Academic Search

Laboratory characterization studies have investigated the processing variability of carbonaceous uranium-bearing materials found in sandstone deposits. This work was conducted by the Federal Bureau of Mines in support of its goal to maintain an adequate supply of minerals to meet national economic and strategic needs. Conventional processing produces only partial uranium recovery from these ore materials. Ore samples from New

I. L. Nichols; A. G. Lawrence; D. C. Seidel

1979-01-01

303

Fractures and stresses in Bone Spring sandstones  

SciTech Connect

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.

Lorenz, J.C.; Warpinski, N.R.; Sattler, A.R.; Northrop, D.A.

1990-09-01

304

Exploration in Jurassic of North Mafla, eastern Gulf of Mexico  

Microsoft Academic Search

Exploration in North Mafla focuses on general categories of prospects, potential reservoirs and their associated facies, and seismic modeling of available well control. Jurassic prospects in North Mafla can be classified into four general categories: (1) basement-related structures: (2) closures associated with the Pensacola-Destin peripheral fault trend, (3) salt anticlines, and (4) prospects associated with the interregional structural highs. Each

Kemmer

1987-01-01

305

Basic aspects of Jurassic landscape development in southeastern central Asia  

SciTech Connect

Based on detailed lithofacies and mineralogical-petrographic studies of the Jurassic terrigenous-carbonate-salt-bearing formations and of changes in characteristics of the basic cycles horizontally and vertically, five paleolandscape development stages have been identified. Each corresponds to a given time interval and geotectonic phase. Paleogeographic charts were constructed for each of the stages. They trace landscape changes in space and time.

Timofeev, P.P.; Bebeshev, I.I.; Makarov, Yu.V.

1986-11-01

306

Organic Walled Phytoplankton Response to Changes in Early Jurassic Paleoceanography  

Microsoft Academic Search

The Early Jurassic is considered to be a watershed phase in the evolution of two groups of photosynthetic phytoplankton taxa, i.e. coccolithophorids and thecate dinoflagellates. Both groups are important primary producers in the contemporary ocean. Especially the Upper Pliensbachian has caught our attention, since this interval shows rapid diversification of phytoplankton and directly precedes the Toarcian Oceanic Anoxic Event. The

B. van de Schootbrugge; T. R. Bailey; M. E. Katz; J. D. Wright; S. Feist-Burkhardt

2003-01-01

307

Triassic-Jurassic Mass Extinction: Evidence for Bolide Impact?  

Microsoft Academic Search

The Triassic-Jurassic (TJ) mass extinction event is one of the most severe in geologic history and is one of the five largest in the Phanerozoic with as many as 80% of the species lost. It is also one of the most poorly understood. Only a few geologic sections have been identified for the TJ extinction and most of those are

R. Perry; L. Becker; J. Haggart; R. Poreda

2003-01-01

308

A NEW SAUROPOD FROM THE JURASSIC OF PATAGONIA 1  

Microsoft Academic Search

Thanks to the excellent works of Lydekker and Huene, based principally on the materials which form part of the collections of the Museum of La Plata and were published in its Anales, the Cretaceous Argentine dinosaurs, especially the Saurischia, are known, if not completely, at least satisfactorily. In contrast, of the Jurassic representatives of these reptiles in our territory until

Angel Cabrera

309

Mass mutations of insects at the Jurassic\\/Cretaceous boundary?  

Microsoft Academic Search

Diverse fossil insect assemblages near the Jurassic\\/ Cretaceous transition from the Shar-Teg in Mongolia comprise frequent deformed species. These (first known) mass fossil animal deformities, expressed as fusions of veins changing the wing geometry, probably represent heritable mutations. They accumulated as a result of a changed structure of selective pressure, and are unique in showing how individual variations may be

PETER VRŠANSKÝ

2005-01-01

310

Apatite Fission-Track Analysis of the Middle Jurassic Todos Santos Formation from Chiapas, Mexico.  

NASA Astrophysics Data System (ADS)

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

Abdullin, Fanis; Solé, Jesús; Shchepetilnikova, Valentina; Solari, Luigi; Ortega-Obregón, Carlos

2014-05-01

311

Hydrocarbon potential of a new Jurassic play, central Tunisia  

SciTech Connect

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.

Beall, A.O. (Arthur O. Beall International E P, Houston, TX (United States)); Law, C.W. (Geomath, Houston, TX (United States))

1996-01-01

312

"When I am lonely the mountains call me": the impact of sacred geography on Navajo psychological well being.  

PubMed

As we approach the twenty-first century, sacred geography continues to have a profound impact on Navajo psychological well being. This article explores the extent of the Navajo's bond with their homeland through an emphasis on orderly conditions in their world view, myths, and ceremonies. When traditional Navajos leave their homeland to pursue educational and professional endeavors or to seek biomedical treatment, a sense of emotional dislocation can undermine their success. The emotional trauma goes far beyond mere homesickness because it is based on an often unconscious sense of having violated the moral order of the universe. It is essential that mental health professionals respond with sensitivity to this issue by understanding the extent to which the sacred mountains and other landforms serve as a vital source of spiritual strength. PMID:9141297

Griffin-Pierce, T

1997-01-01

313

Synkinematic quartz cementation in partially open fractures in sandstones  

NASA Astrophysics Data System (ADS)

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 80°C 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 µm/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.

Ukar, Estibalitz; Laubach, Stephen E.; Fall, Andras; Eichhubl, Peter

2014-05-01

314

Paleomagnetism of the Middle-Late Jurassic to Cretaceous red beds from the Peninsular Thailand: Implications for collision tectonics  

NASA Astrophysics Data System (ADS)

Jurassic to Cretaceous red sandstones were sampled at 33 sites from the Khlong Min and Lam Thap formations of the Trang Syncline (7.6°N, 99.6°E), the Peninsular Thailand. Rock magnetic experiments generally revealed hematite as a carrier of natural remanent magnetization. Stepwise thermal demagnetization isolates remanent components with unblocking temperatures of 620-690 °C. An easterly deflected declination ( D = 31.1°, I = 12.2°, ?95 = 13.9°, N = 9, in stratigraphic coordinates) is observed as pre-folding remanent magnetization from North Trang Syncline, whereas westerly deflected declination ( D = 342.8°, I = 22.3°, ?95 = 12.7°, N = 13 in geographic coordinates) appears in the post-folding remanent magnetization from West Trang Syncline. These observations suggest an occurrence of two opposite tectonic rotations in the Trang area, which as a part of Thai-Malay Peninsula received clockwise rotation after Jurassic together with Shan-Thai and Indochina blocks. Between the Late Cretaceous and Middle Miocene, this area as a part of southern Sundaland Block experienced up to 24.5° ± 11.5° counter-clockwise rotation with respect to South China Block. This post-Cretaceous tectonic rotation in Trang area is considered as a part of large scale counter-clockwise rotation experienced by the southern Sundaland Block (including the Peninsular Malaysia, Borneo and south Sulawesi areas) as a result of Australian Plate collision with southeast Asia. Within the framework of Sundaland Block, the northern boundary of counter-clockwise rotated zone lies between the Trang area and the Khorat Basin.

Yamashita, Itaru; Surinkum, Adichat; Wada, Yutaka; Fujihara, Makoto; Yokoyama, Masao; Zaman, Haider; Otofuji, Yo-ichiro

2011-02-01

315

Rock-fall Hazard Assessment of the Aspen Forest Trail, Navajo National Monument, Arizona  

NSDL National Science Digital Library

Created by Edwin F. Harp and Gerald F. Wieczorek of the United States Geological Survey (USGS), this resource is an effort to assess the stability of a section of the Aspen Forest Trail to Betatakin Ruins, Navajo National Monument, Arizona, and to discuss methods of remediation and options for reopening the trail. This report includes a description and analysis of the discontinuities that affect slope stability along the trail and recommendations for access to Betatakin Ruins in consideration of the rock-fall hazards. A list of external references is also provided.

Harp, Edwin F.; Wieczorek, Gerald F.

2009-05-21

316

Weatherization assistance program. Final monitoring report for Arizona, California, the Navajo Nation, and Nevada  

SciTech Connect

Stroud, Inc., was awarded a contract by the Department of Energy San Francisco Operations Office (DOE-SAN) to evaluate the weatherization programs for selected grantees and subgrantees in Arizona, California, the Navajo Nation, and Nevada. This final report summarizes both the findings and the recommendations that emerged from the forty (40) visits to grantees and subgrantees. The remarks are not intended to be detailed and exhaustive. Specific problems, achievements, and recommendations are to be found in the narrative reports. But some findings and traits are sufficiently general that they warrant being included in this final report. The recommendations reflect those general characteristics.

Not Available

1986-08-01

317

Multistage variable probability forest volume inventory. [the Defiance Unit of the Navajo Nation  

NASA Technical Reports Server (NTRS)

An inventory scheme based on the use of computer processed LANDSAT MSS data was developed. Output from the inventory scheme provides an estimate of the standing net saw timber volume of a major timber species on a selected forested area of the Navajo Nation. Such estimates are based on the values of parameters currently used for scaled sawlog conversion to mill output. The multistage variable probability sampling appears capable of producing estimates which compare favorably with those produced using conventional techniques. In addition, the reduction in time, manpower, and overall costs lend it to numerous applications.

Anderson, J. E. (principal investigator)

1979-01-01

318

Crossroads and Connections: An Evolving Relationship between NASA and the Navajo Nation  

NASA Astrophysics Data System (ADS)

Is working with Native Americans business as usual? We live in a project-based world that operates on three-to-five-year grants. A long term commitment can be next to impossible to keep, even if you have the best of intentions. Are there things one "must know" before approaching an indigenous population? How is it best to evaluate projects and programs involving Native Americans? In the NASA and the Navajo Nation project, which will turn five in January, 2010, we have compiled some key lessons learned that we hope will inform and encourage future partnerships between the space science education and Native American communities.

Scalice, D.; Carron, A.

2010-08-01

319

Diversity and paleogeographic distribution of Early Jurassic plesiosaurs  

NASA Astrophysics Data System (ADS)

Early Jurassic plesiosaurs, a group of extinct marine reptiles, were one of the first groups to be described in the history of vertebrate paleontology. Nevertheless, the paleogeographic distribution and the taxonomic diversity of these forms are still unclear, particularly because most descriptions and taxonomic attributions were realized during the mid 19th to early 20th century. Here we investigate the paleodiversity and paleogeographic distribution of Early Jurassic plesiosaurs using an extensive taxonomic and anatomical revision of most known Early Jurassic specimens. We also present an examination of the biostratigraphic and sedimentological framework of deposits in which these specimens were discovered, in order to decipher whether their fossil record reflects primary paleobiological trends or taphonomic/discovery biases. Early Jurassic Plesiosaur diversity appears to reach its maximum during the Toarcian (falciferum-bifrons ammonite zones). Nevertheless, the inclusion of ghost lineages into the diversity curves indicates that this pattern likely reflects discovery and taphonomical biases rather than primary biodiversity trends. Indeed, most strata where numerous plesiosaurs species were discovered correspond to sediments that were deposited under poorly-oxygenated conditions and exploited at least in a semi-industrial way during the 1800's-1950's. The Lower Jurassic fossiliferous localities that yielded identifiable plesiosaur species are only found in Western Europe (England, Germany, and France). In Europe, the Toarcian stage is the only interval where more than one fossiliferous locality is known (the Hettangian, Sinemurian and Pliensbachian stages being each represented by only one locality where specimens are identifiable at the species level). The different Toarcian fossiliferous sites of Europe do not bear any single common taxon, suggesting a high degree of endemism in Early Jurassic plesiosaurs. Nevertheless, these sites are fundamentally diachronous at the ammonite zone level; this absence of shared taxa might hence reflect temporal changes rather than paleogeographic trends. Further data are required to determine whether if this pattern is a consequence of truly limited paleobiogeographic ranges or the result of high rates of turnover. In addition, future fossil discoveries and refinements of the phylogenetic relationships are required to precise the evolution of this diversity at a higher stratigraphic resolution, and hence determine how plesiosaurs responded to severe environmental change that punctuated this period (i.e. Early Hettangian and Early Toarcian mass extinction events).

Vincent, Peggy; Suan, Guillaume

2010-05-01

320

Porosity and Permeability of Jurassic-Triassic Formations of the South Georgia Rift Basin: Potential Implications for CO2 Storage  

NASA Astrophysics Data System (ADS)

Porosity and permeability are critical for evaluating reservoir injectivity and seal integrity for subsurface CO2 storage. Both properties are needed to determine the effective CO2 storage capacity. In addition, the ability to model and understand the physical interactions of the CO2 reservoir systems under in situ conditions is dependent on the reservoir porosity. We present results of rock physics evaluation of the porosity and permeability of the buried Jurassic-Triassic formations of the South Georgia Rift (SGR) basin using existing well and new experimental data. The SGR basin covers parts of South Carolina, Georgia, Alabama, and Florida and is buried beneath Cretaceous and younger Coastal Plain sediments. We focused our study on the South Carolina portion of the basin that has been identified in the Carbon Sequestration Atlas of United States and Canada as containing saline formations suitable for subsurface CO2 storage. Results of our rock physics analysis confirm the presence of porous reservoir units capped by low-porosity diabase sills. These potential reservoirs appear to have the capacity (pore volume and porosity) to store significant quantities of supercritical CO2. Our analysis further suggests that the SGR basin may contain distinct porosity-permeability regimes (geo-hydrologic systems) that are influenced by depositional environments. These regimes are: (1) high-porosity, low/medium permeability, as observed in the Norris Lightsey well with Triassic formation porosity of 20 - 32.5 percent and core-derived permeability of 1.5 - 8.9 mD, and (2) low-porosity, low-permeability, based on the average total porosity of 6.3 percent and permeability of 6.6 (E-5) - 1.6 (E-2) mD reported in the literature for the Dunbarton Triassic sediments. The Norris Lightsey sedimentary rocks are primarily lacustrine deposits and consist of fine-grained Triassic sandstone with interbedded layers of siltstone and mudstone, while the Dunbarton basin is dominated by fluvial fine-to very fine-grained sandstone. We believe that our hypothesis of distinct geo-hydrologic systems for the SGR basin requires further evaluation. We will discuss the results of new experiments on selected Jurassic and Triassic core samples that are designed to better understand and quantify the distribution of porosity and permeability both locally and regionally.

Akintunde, O. M.; Knapp, C. C.; Knapp, J. H.; Prasad, M.; Olsen, P. E.

2011-12-01

321

Fractures and stresses in Bone Spring sandstones  

SciTech Connect

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.

Warpinski, N.R.; Sattler, A.R.; Lorenz, J.C.; Northrop, D.A.

1992-06-01

322

Preserving Native American petroglyphs on porous sandstone  

USGS Publications Warehouse

A new method of chemical treatment is proposed to improve the durability of soft, porous sandstones onto which Native American petroglyphs have been carved. Cores of Dakota Sandstone from the Faris Cave site, located along the Smoky Hill River in Ellsworth County, Kansas, were treated with ethyl silicate dissolved in a lightweight ketone carrier, and some cores were subsequently treated with a combination of ethyl silicate and silane using the same solvent. Measurement of the resulting physical properties, when compared to untreated cores, indicate the treatments substantially increased the compressive strength and freeze-thaw resistance of the stone without discoloring the stone or completely sealing the pore system. The treatment increases the durability of the stone and provides a method for preserving the petroglyphs at the site. After treating test panels at the site, the petroglyphs were treated in like manner.

Grisafe, D. A.

1996-01-01

323

Isotopic fractionation of uranium in sandstone  

USGS Publications Warehouse

Relatively unoxidized black uranium ores from sandstone deposits in the western United States show deviations in the uranium-235 to uranium-234 ratio throughout a range from 40 percent excess uranium-234 to 40 percent deficient uranium-234 with respect to a reference uranium-235 to uranium-234 ratio. The deficient uranium-234 is leached preferentially to uranium-238 and the excess uranium-234 is believed to result from deposition of uranium-234 enriched in solutions from leached deposits.

Rosholt, J. N.; Shields, W. R.; Garner, E. L.

1963-01-01

324

Thermophysical study of sandstone reservoir rocks  

Microsoft Academic Search

Thermal conductivity of both dry and fully water (brine solution, 5g\\/l NaCl concentration) saturated rocks have been measured for 35 sandstone core samples obtained from both Hungary and Egypt. Measurements are executed in order to look for thermal anisotropy. The rock porosity, permeability and density were measured beside thermal conductivity, while some correlations were performed in order to differentiate among

Abdel Moktader A. El Sayed

2011-01-01

325

Total petroleum systems of the Paleozoic and Jurassic, Greater Ghawar Uplift and adjoining provinces of central Saudi Arabia and northern Arabian-Persian Gulf  

USGS Publications Warehouse

The greater Paleozoic and Jurassic petroleum systems of the Arabian Peninsula form two of the most prolific petroleum-producing systems in the world. Source rocks of these systems extend throughout the eastern Arabian Peninsula and Arabian-Persian Gulf. Primary elements of these Paleozoic and Jurassic petroleum systems?source, reservoir, and seal rocks?are of great areal extent and exceptional quality. The combination of these regionally extensive, exceptional petroleum-system elements, and the formation of large subtle structural closures prior to, or coincident with, peak oil generation and migration, have produced oil and gas fields with reserve volumes second to none. Two total petroleum systems (TPS), one of Paleozoic age and one of Jurassic age, in the central part of the Arabian Peninsula are identified in this report. The Central Arabia Qusaiba-Paleozoic TPS and the Arabian Sub-Basin Tuwaiq/Hanifa-Arab TPS of Jurassic age encompass the Greater Ghawar Uplift Province (USGS Province 2021) and portions of adjoining geologic provinces. Structures that trap hydrocarbons in these systems are mostly (1) large, gentle anticlines formed from reactivated basement fault blocks, (2) salt domes that resulted from halokinesis, or (3) structural traps resulting from a combination of these two processes. Major tectonic events that created these structures resulted from early Zagros rifting during the Early Triassic and two Alpine tectonic episodes that occurred during the Late Cretaceous and middle to late Tertiary. Hydrocarbons of the Central Arabia Qusaiba-Paleozoic TPS are sourced mainly by organic-rich, so-called ?hot shale? that occurs in the basal part of the Lower Silurian Qusaiba Member of the Qalibah Formation. Oil and gas are produced mainly from sandstones of the Permian Unayzah and Devonian Jauf Formations, and from basal transgressive marine sandstones and cyclic, dolomitic shelf-carbonates of the Late Permian Khuff Formation. Two assessment units (AU) are recognized in the Central Arabia Qusaiba-Paleozoic TPS that are related to type of structural trap and presence of underlying Infracambrian salt: (1) the onshore Central Arch Horst-Block Anticlinal Oil and Gas AU, and (2) the mostly offshore North Gulf Salt Basin Structural Gas AU. The mean total volume of undiscovered resource for the Central Arabia Qusaiba-Paleozoic TPS is estimated at about 108 billion barrels of oil equivalent (BBOE). Oil of the Arabian Sub-Basin Tuwaiq/Hanifa-Arab TPS is sourced by organic-rich, marine carbonates of the Jurassic Tuwaiq Mountain and Hanifa Formations. These source rocks were deposited in two of three intraplatform basins during the Jurassic and, where thermally mature, have generated a superfamily of oils with distinctive geochemical characteristics. Oils were generated and expelled from these source rocks beginning in the Cretaceous at about 75 Ma. Hydrocarbon production is from 3 cyclic carbonate-rock reservoirs of the Arab Formation that are sealed by overlying anhydrite. Several giant and supergiant fields, including the world?s largest oil field at Ghawar, Saudi Arabia, produce mostly from the Arab carbonate-rock reservoirs. Two assessment units are also recognized in the Arabian Sub-Basin Tuwaiq/Hanifa-Arab TPS that are similarly related to structural trap style and presence of underlying Infracambrian salt: (1) an onshore Horst-Block Anticlinal Oil AU, and (2) a mostly offshore Salt-Involved Structural Oil AU. The mean total volume of undiscovered resource for the Arabian Sub-Basin Tuwaiq/Hanifa-Arab TPS is estimated at about 49 billion barrels of oil equivalent (42 billion barrels of oil, 34 trillion feet of gas, and 1.4 billion barrels of natural gas liquids).

Pollastro, Richard M.

2003-01-01

326

Matrix versus fracture permeability in a regional sandstone aquifer (Wajid sandstone, SW Saudi Arabia)  

NASA Astrophysics Data System (ADS)

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).

Al Ajmi, Hussain; Hinderer, Matthias; Rausch, Randolf; Hornung, Jens; Bassis, Alexander; Keller, Martin; Schüth, Christoph

2014-06-01

327

A basal tyrannosauroid dinosaur from the Late Jurassic of China.  

PubMed

The tyrannosauroid fossil record is mainly restricted to Cretaceous sediments of Laurasia, although some very fragmentary Jurassic specimens have been referred to this group. Here we report a new basal tyrannosauroid, Guanlong wucaii gen. et sp. nov., from the lower Upper Jurassic of the Junggar Basin, northwestern China. G. wucaii is the oldest known tyrannosauroid and shows several unexpectedly primitive pelvic features. Nevertheless, the limbs of G. wucaii share several features with derived coelurosaurs, and it possesses features shared by other coelurosaurian clades. This unusual combination of character states provides an insight into the poorly known early radiation of the Coelurosauria. Notably, the presumed predatory Guanlong has a large, fragile and highly pneumatic cranial crest that is among the most elaborate known in any non-avian dinosaur and could be comparable to some classical exaggerated ornamental traits among vertebrates. PMID:16467836

Xu, Xing; Clark, James M; Forster, Catherine A; Norell, Mark A; Erickson, Gregory M; Eberth, David A; Jia, Chengkai; Zhao, Qi

2006-02-01

328

A late Jurassic pterosaur (Reptilia, Pterodactyloidea) from northwestern Patagonia, Argentina  

NASA Astrophysics Data System (ADS)

A small to medium-sized pterodactyloid pterosaur (wingspan approximately 1.10 m) from the Upper Jurassic (middle-late Tithonian) marine deposits of the Vaca Muerta Formation of Patagonia (Los Catutos area, central Neuquén Province, Argentina) is reported. The specimen lacks the skull but constitutes a nearly complete postcranial skeleton, which includes cervical and dorsal vertebrae; a few thoracic ribs; both pectoral girdles; the left pelvic girdle; a proximal right wing (humerus, ulna, and radius) and metacarpal IV; a left wing that lacks only wing phalanx four; and both hindlimbs, the right one without the foot. Ontogenetic features suggest that the new fossil corresponds to a relatively mature individual, probably a subadult. Observed characters support its assignment to the Archaeopteroactyloidea, a basal clade within the Pterodactyloidea. This specimen is the second pterosaur from Los Catutos and the most complete Jurassic pterosaur so far known from South America.

Codorniú, Laura; Gasparini, Zulma; Paulina-Carabajal, Ariana

2006-03-01

329

Frisco City sand: New Jurassic reservoir in southwest Alabama  

Microsoft Academic Search

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° 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

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

1989-01-01

330

Jurassic sedimentary basins in the Central Asian orogenic belt  

SciTech Connect

The principal stages of development of Jurassic sedimentary basins (from their origin to the end of their existence) in the Central Asian orogenic belt are considered. The interrelations of the basins with the surrounding paleorises are investigated. Paleogeographic maps are compiled representing the evolution of paleolandscapes and revealing their interrelations in space and time for each stage. Areas with the highest prospects for coal are found.

Bebeshev, I.I. [Geological Institute, Moscow (Russian Federation)

1995-05-01

331

New paleomagnetic data from Jurassic Sediments from Sardinia  

NASA Astrophysics Data System (ADS)

The dynamic history of the Corso-Sardinian microplate since Oligocene times is well defined based on numerous geologic, geophysical and paleomagnetic studies (e.g. Vigliotti and Langenheim 1995), especially the counter clockwise rotation and the associated opening of the Liguro-Provençal ocean (Gattacceca et al., 2007). In the early 80’s Horner and Lowrie (1981) published paleomagnetic results from Jurassic and Triassic carbonates from the Orosei region, eastern Sardinia. Although these data are of rather poor quality they nevertheless indicate a two step rotational history of the microplate. Horner and Lowrie concluded that a cw rotation of ~70° -90° is required in order to compensate the opening of the Liguro-Provençal ocean and to restore Sardinia into its pre-Oligocene position. However these results are of very limiting regional spread and do not allow to test the structural integrity of the island for post-Jurassic times. Data for the Permian basins and the Carboniferous dyke swarms indicate large rotations between Northern, Central and Southern Sardinia (Emmer et al., 2005). In order to better constrain the timing of these movements a detailed paleomagnetic study was undertaken covering all areas of Sardinia where Jurassic rocks have been identified. A total of 367 samples from 46 sites was subjected to stepwise thermal and AF demagnetization experiments, yielding well defined characteristic directions of magnetization. The primary character of this magnetization is supported by positive fold and reversal tests. The resulting mean direction, based on 31 sites (?_95=8.4°) is D = 273.6° and I=+43.0° (Sardinian coordinates) is in very good agreement with the older data published by Horner and Lowrie (1981). Furthermore it indicates that no internal rotation of post-Jurassic age affected the island. This result has important implications for the interpretation of the paleomagnetically identified rotations for Permian basins and Permo- Carboniferous dyke swarms of Sardinia.

Kirscher, U.; Bachtadse, V.; Muttoni, G.; Aubele, K.

2009-12-01

332

Carbon cycle changes during the Triassic-Jurassic transition  

Microsoft Academic Search

The end-Triassic is regarded as one of the five major mass extinction events of the Phanerozoic. This time interval is marked by up to 50% of marine biodiversity loss and major changes in terrestrial ecosystems. Mass extinction events are often marked by changes in the global carbon cycle. The reality and nature of C-cycle changes at the Triassic-Jurassic (T-J) transition

M. Ruhl

2010-01-01

333

Magnetostratigraphy of the Lower Jurassic (Hettangian-Sinemurian)  

NASA Astrophysics Data System (ADS)

Magnetostratigraphy and correlation to the Geomagnetic Polarity Time Scale (GPTS) constitute a standard dating tool in Earth Sciences. When integrated with biostratigraphy and especially cyclostratigraphy, magnetostratigraphy allows high-resolution correlations all over the world, because paleomagnetic polarity reversals can geologically be seen as globally synchronous events. It is therefore the stratigraphic tool of choice to perform correlations between continental and marine realms. An integrated astronomical time scale, which has been achieved for most of the Neogene and is in progress for the Palaeogene and Mesozoic, provides high resolution and accuracy. The Geologic Time Scale (GTS) for the Early Jurassic is far less robust (Gradstein et al., 2004, 2012) because magnetostratigraphic records of marine Hettangian and Sinemurian successions are rare and equivocal (Gallet et al., 1990; Yang et al., 1996). Consequently, the Global Stratotype Section and Points (GSSP's) for the Hettangian (Kuhjoch; Austria) and Sinemurian (East Quantoxhead; UK) are mainly defined on biostratigraphic (ammonite) arguments (Hillebrandt et al., 2007; Bloos and Page, 2002). Cyclostratigraphic analyses from the Lower Jurassic marine successions at St. Audrie's Bay and East Quantoxhead located on the west Somerset coast on the southern side of the Bristol Channel Basin (UK) resulted in an independent astronomical framework for the Hettangian Stage, allowing to locate the stratigraphic position of the marine de?ned Triassic-Jurassic and Hettangian-Sinemurian boundary in the continental realm (Ruhl et al., 2010). We will present the magnetostratigraphy of the Hettangian and lower Sinemurian successions of St. Audrie's Bay and East Quantoxhead, which will be used to evaluate the marine-continental correlations in the recovery interval following the end-Triassic mass extinction and to develop a more robust GPTS for the Lower Jurassic.

Hüsing, Silja Katherine; Abels, Hemmo; Deenen, Martijn; Ruhl, Micha; Krijgsman, Wout

2013-04-01

334

Environmental significance of foraminiferal assemblages dominated by small-sized Ammodiscus and Trochammina in Triassic and Jurassic delta-influenced deposits  

NASA Astrophysics Data System (ADS)

The sediment packages analyzed for benthic foraminifera consist of mudstones with interbedded sandstones deposited in shallow delta-influenced shelf to deltaic environments. The sections are located in Spitsbergen, the Barents Sea, northern North Sea and Yorkshire, and range in age from Late Triassic to Middle Jurassic. Salient features of the foraminiferal successions are: (1) The assemblages consist entirely or dominantly of agglutinated taxa. (2) The faunal diversities are extremely low. (3) The dominant genera are Ammodiscus and Trochammina. (4) The species are generally of small size compared to usual dimensions within the genera. The features listed above suggest that the assemblages were adapted to restricted conditions (clearly divergent from those of a normal marine shelf), where the main limiting factors were low salinity and reduced amount of dissolved oxygen in unstable, storm-influenced environments. Evidence for environmental conditions is obtained from modern analogues, although the large evolutionary changes in foraminifera during post-Jurassic time make it difficult to find such analogues. Additional information is derived from functional morphology, sedimentary features and paleogeography. The analyzed sediment packages show close faunal similarities suggesting opening of a marine pathway, which connected the paleo-Arctic Ocean with the western European shelf seas in Early Jurassic. A depositional biofacies model of the small-sized Ammodiscus- Trochammina assemblages envisages a delta-influenced shelf environment, where high freshwater influx would have created a density-stratified water column with a tendency to develop hypoxic conditions in its deeper parts. The depth interval between fair-weather and storm wave base (the offshore-transition zone) is indicated as the habitat of the small-sized Ammodiscus- Trochammina assemblages. In this zone, benthic biota would have been stressed by intermittent periods with moderate hypoxia combined with lowered salinity and storm impacts.

Nagy, Jenö; Hess, Silvia; Alve, Elisabeth

2010-04-01

335

Navajo Neurohepatopathy Is Caused by a Mutation in the MPV17 Gene  

PubMed Central

Navajo neurohepatopathy (NNH) is an autosomal recessive disease that is prevalent among Navajo children in the southwestern United States. The major clinical features are hepatopathy, peripheral neuropathy, corneal anesthesia and scarring, acral mutilation, cerebral leukoencephalopathy, failure to thrive, and recurrent metabolic acidosis with intercurrent infections. Infantile, childhood, and classic forms of NNH have been described. Mitochondrial DNA (mtDNA) depletion was detected in the livers of two patients, suggesting a primary defect in mtDNA maintenance. Homozygosity mapping of two families with NNH suggested linkage to chromosome 2p24. This locus includes the MPV17 gene, which, when mutated, causes a hepatocerebral form of mtDNA depletion. Sequencing of the MPV17 gene in six patients with NNH from five families revealed the homozygous R50Q mutation described elsewhere. Identification of a single missense mutation in patients with NNH confirms that the disease is probably due to a founder effect and extends the phenotypic spectrum associated with MPV17 mutations.

Karadimas, Charalampos L.; Vu, Tuan H.; Holve, Stephen A.; Chronopoulou, Penelope; Quinzii, Catarina; Johnsen, Stanley D.; Kurth, Janice; Eggers, Elizabeth; Palenzuela, Lluis; Tanji, Kurenai; Bonilla, Eduardo; De Vivo, Darryl C.; DiMauro, Salvatore; Hirano, Michio

2006-01-01

336

Examining the Lives of Navajo Native American Teenage Mothers in Context: A 12- to 15-Year Follow-Up  

ERIC Educational Resources Information Center

In 1992 and 1995, data were collected from 29 Navajo, reservation-residing teenage mothers. In 2007, follow-up data from 69% (n = 20) of the original sample were collected. Intensive interviews, grounded in ecological systems theory (U. Bronfenbrenner, 1989), allowed for contextual examination of the women's developmental trajectories. Significant…

Dalla, Rochelle L.; Jacobs-Hagen, Susan B.; Jareske, Betsy K.; Sukup, Julie L.

2009-01-01

337

Navajo Environmental Health Review by the National Environmental Health Association (Window Rock, Arizona, May 24-27, 1976).  

ERIC Educational Resources Information Center

The Indian Health Committee met with key staff of the Indian Health Service (IHS) Area Office to review the environmental health services provided on the Navajo Reservation and make recommendations for improvement or expansion of current programs, if needed. Recommendations were made regarding environmental health and institutional personnel,…

Navajo Health Authority, Window Rock, AZ.

338

Navajo Code Talker Joe Morris, Sr. shared insights from his time as a secret World War Two messenger  

NASA Technical Reports Server (NTRS)

Navajo Code Talker Joe Morris, Sr. shared insights from his time as a secret World War Two messenger with his audience at NASA's Dryden Flight Research Center on Nov. 26, 2002. NASA Dryden is located on Edwards Air Force Base in California's Mojave Desert.

2002-01-01

339

A Study of Parental Attitudes and Values Towards Education on the Navajo and Hopi Reservations. Part II, Parental Attitudes [Chinle].  

ERIC Educational Resources Information Center

Objectives of this study were (1) to determine the parental attitudes of those parents who reside in the Chinle, Keams Canyon, Kayenta, Ganado, Window Rock, or Tuba City school district toward public education on the Navajo and Hopi reservations in the areas of teachers, curriculum, social behaviors of children, school services, school policies,…

Biglin, J. E.; And Others

340

A Study of Parental Attitudes and Values Towards Education on the Navajo and Hopi Reservations. Part II, Parental Attitudes [Ganado].  

ERIC Educational Resources Information Center

Objectives of this study were (1) to determine the parental attitudes of those parents who reside in the Chinle, Keams Canyon, Kayenta, Ganado, Window Rock, or Tuba City school district toward public education on the Navajo and Hopi reservations in the areas of teachers, curriculum, social behaviors of children, school services, school policies,…

Biglin, J. E.; And Others

341

A Study of Parental Attitudes and Values Towards Education on the Navajo and Hopi Reservations. Part II, Parental Attitudes [Kayenta].  

ERIC Educational Resources Information Center

Objectives of this study were (1) to determine the parental attitudes of those parents who reside in the Chinle, Keams Canyon, Kayenta, Ganado, Window Rock, or Tuba City school district toward public education on the Navajo and Hopi reservations in the areas of teachers, curriculum, social behaviors of children, school services, school policies,…

Biglin, J. E.; And Others

342

77 FR 50686 - Notice of Approval of Title V Operating Permit for Peabody Western Coal Company (Navajo Nation...  

Federal Register 2010, 2011, 2012, 2013

...FRL-9717-6] Notice of Approval of Title V Operating Permit for Peabody Western...71, has issued a federal Clean Air Act Title V operating permit to Peabody Western Coal...operations on the Navajo reservation, Title V Operating Permit No. NN-OP...

2012-08-22

343

Saad Naakih Bee'enootiilji Na'alkaa: Restructuring the Teaching of Language and Literacy in a Navajo Community School.  

ERIC Educational Resources Information Center

Describes the 10-year development of the Rough Rock English-Navajo Language Arts Program (RRENLAP) to improve the teaching of language, literacy, and biliteracy. Discusses collaboration between Rough Rock and the Hawaii-based Kamehameha Early Education Program, key RRENLAP instructional features, and the role of bilingual teachers in the struggle…

Dick, Galena Sells; And Others

1994-01-01

344

Factors Involved in Job Satisfaction Among Teachers in the Bureau of Indian Affairs System on the Navajo Reservation.  

ERIC Educational Resources Information Center

One of the principal problems the Bureau of Indian Affairs (BIA) has in carrying out its responsibility to educate Indian children is the high turnover rate among its teachers; a large proportion of teachers in the BIA school system leave after their first year or second year of work. Teachers at six elementary schools on the Navajo Reservation…

Smith, Frederick D.

1977-01-01

345

A combined diffusion/kinetic/thermodynamic framework for the prediction of porosity reduction in sedimentary basin sandstones over geologic timeframes  

SciTech Connect

A combined petrographic/computational study of the Jurassic North Sea Sandstones indicates that porosity reduction in these rocks is dominated by the dissolution of quartz at mica contacts, the diffusion of dissolved silica away from these surfaces, and the subsequent precipitation of secondary quartz. In many instances the bulk of the quartz dissolution occurs at mica rich stylolites. To quantify this silica transport/porosity reduction process as a function of the time/temperature/depth history of a given sandstone, a comprehensive computational framework was developed to simultaneously solve rates of kinetically controlled mineral dissolution/precipitation reactions coupled to diffusional transport and homogeneous equilibrium of aqueous species in the solute phase. The mass conservation equations were integrated over geologic timeframes. Calculations carried out with the aid of this algorithm were used to assess the effects of mineralogy, mineral surface area, solution pH, the presence of a separate hydrocarbon phase, and distribution of diagenetic phases on the distribution of porosity and secondary quartz over the history of the North Sea basin.

Oelkers, E.H. (Univ. Paul Sabatier, Toulouse (France). Lab. de Geochimie); Bjorkum, P.A. (STATOIL, Stavanger (Norway). Petrology and Sedimentology); Murphy, W.M. (Southwest Research Inst., San Antonio, TX (United States))

1992-01-01

346

The Upper Triassic to Middle Jurassic strata and floras of the Junggar Basin, Xinjiang, Northwest China  

Microsoft Academic Search

The Upper Triassic to Middle Jurassic strata are well exposed and basically continuous in the Junggar Basin of Xinjiang, Northwest\\u000a China. The Upper Triassic strata include the Huangshanjie Formation (lacustrine facies mainly) and Haojiagou Formation (fluvial\\u000a to fluvial-swamp facies). The Lower Jurassic consists of the coal-bearing Badaowan Formation (fluvial swamp facies) and Sangonghe\\u000a Formation (lacustrine facies mainly). The Middle Jurassic

Ge Sun; Yuyan Miao; Volker Mosbrugger; Abdul R. Ashraf

2010-01-01

347

Fluvial sedimentology of an Upper Jurassic petrified forest assemblage, Shishu Formation, Junggar Basin, Xinjiang, China  

Microsoft Academic Search

McKnight, C. L.. Graham, S A.. Carroll. A. R.. Gan. Q., Dilcher, D. L, Min Zhao and Yun Hal Liang. 1990 Fluvial sedimeutology of au Upper JurassIC petflfied forest assemblage. Shishu Formation. Junggar Basm, Xinjiang, Chma. Palaeogeogr.. PalaeoclImatol. Palueoecol., 79' 1-9. A remarkable petflfied forest assemblage is preserved 10 the Upper Jurassic Shishu FonnatlOn of the northeastern Junggar basin. Xmjiang

Cleavy L. McKnight; S. A. Graham; A. R. Carrollb; Q GAN; D DILCHER; M ZHAO; Y HAILIANG

1990-01-01

348

Jurassic magmatic bodies of mountainous Crimea in the Bodrak River catchment (Southwestern Crimea)  

Microsoft Academic Search

The synthetic (geological and petrochemical) study of Jurassic magmatic bodies in the catchment of the Bodrak River (mountainous\\u000a Crimea) is conducted. Their structural position and a Middle Jurassic age were determined. The magmatic bodies of mountainous\\u000a Crimea were compared to those of the Lozovskaya zone. The study considers the geodynamic settings of the Middle Jurassic magmatism\\u000a in mountainous Crimea.

A. V. Latyshev; D. I. Panov

2008-01-01

349

Potential Triassic and Jurassic CO2 Storage Reservoirs in the Skagerrak Area  

NASA Astrophysics Data System (ADS)

Based on a screening study for CO2 storage in the Skagerrak area, we have focused on the Upper Triassic/Lowermost Jurassic Gassum Formation. A large shallow dipping reservoir structure has been identified in the northern Skagerrak area. The current study presents reservoir characteristics of the Gassum formation in the Fjerritslev trough and onto the Skagerrak Kattegat platform, and the corresponding reservoir model. This reservoir model is part of an ongoing interdisciplinary project with the overall goal to establish a basis for large-scale handling of CO2 in this area, including regional CO2 source and capture possibilities, transportation and infrastructure, possible storage sites as well as legal aspects relating to the whole CCS chain. The shallow dipping aquifer is regionally exteded and mapped in the Norwegian-Danish Basin, the Fjerritslev trough, and onto the Skagerrak Kattegat platform, and is found deeper than 800 m below sea level. In the south the formation is affected by salt tectonics (salt pillows, diapirs), while forming gently dipping layer structures towards the north. The Gassum reservoir consists of mainly shallow marine shoreface sandstones with associated estuarine deposits possibly deposited during sea-level low stands. Thickness of Gassum Formation from Danish wells is 70 - 220 m with sand to shale ratios between 60 - 70%. Based on the study, an injection well is proposed 50 km offshore Norway. The proposed injection depth is 2070 m with the reservoir pinch-out 38 km away towards north where the top reservoir is 117 m below the Quaternary sediments. The southern portion of the reservoir located in Denmark can be characterized from wells drilled for hydrocarbons and geothermal energy. In order to predict the reservoir facies/parameters and to make a realistic geologic model comprising the area closer to Norway, a regional geological model based on sequence stratigraphic interpretations is imperative. Using thicknesses from seismic data a pseudo-well was generated about 50 km north of an existing well in Denmark with the objective to predict facies. A depositional model with sediments sourced from north was assumed. A 50% thickness erosion of highstand sandstones was assumed at each cycle when sea level fell during a low stand. The removed thickness was compensated by non-reservoir transgressive systems tracts sediments (possible aggrading floodplain or lagoonal sediments). As good reservoir porosities (~20%) were found in wells in the south, porosities towards north are expected to be higher due to shallower depth of burial. The sealing properties of transgressive shales overlying the low stand sandstones are also important in local trapping and lateral distribution of the injected CO2. Furthermore the intercalation of shaly layers and permeability heterogeneities developed in prograding sand systems may provide additional trapping capacity to the reservoir. This geologic model is one of the likely scenarios that favors Gassum Formation as a potential CO2 storage reservoir in Skagerrak area and warrant to evaluate the reservoir using other possible scenarios.

Baig, I.; Aagaard, P.; Fawad, M.; Sassier, C.; Faleide, J. I.; Jahren, J.; Gabrielsen, R. H.; Nielsen, L. H.; Kristensen, L.; Bergmo, P. E. S.

2012-04-01

350

Porosity trends of nonreservoir and reservoir sandstones, Anadarko basin, Oklahoma  

SciTech Connect

The porosity of nonreservoir sandstones in Caddo County, Oklahoma, is determined using compensated-neutron and formation-density logs. The authors preliminary data set represents more than 3,000 net ft of Pennsylvanian and Permian age sandstones from 12 well locations. These porosity data and the average porosities of sandstone oil and gas reservoirs within the Anadarko basin of Oklahoma are each compared to a broad, composite set of porosity data from numerous basins that represent sandstones in general, and they are also compared to each other. The porosity of nonreservoir sandstones in Caddo County declines predictably as a power function of increasing thermal maturity for vitrinite reflectance (R{sub 0}) of 0.5 to 1.3%. The rate of porosity decrease with increasing thermal maturity is more rapid than that of the average porosity-R{sub 0} trend of the composite set, but is still within the porosity-R{sub 0} envelope of sandstones in general. Hydrocarbon reservoir sandstones of the Anadarko basin, however, follow a different pattern. Their rate of porosity loss is much slower than that of both sandstones in general, and nonreservoir sandstones of Caddo County. This slow rate of porosity decline with increasing R{sub 0} could be due to inhibiting effects of early hydrocarbon emplacement on diagenesis and (or) to the bias of economic selection. In any case, as R{sub 0} increases beyond about 1%, the porosity of Anadarko basin reservoir sandstones is anomalously high compared to both nonreservoir Anadarko basin sandstones and sandstones in general.

Hester, T.C.; Schmoker, J.W. (Geological Survey, Denver, CO (United States))

1991-03-01

351

Porosity trends of nonreservoir and reservoir sandstones, Anadarko basin, Oklahoma  

Microsoft Academic Search

The porosity of nonreservoir sandstones in Caddo County, Oklahoma, is determined using compensated-neutron and formation-density logs. The authors preliminary data set represents more than 3,000 net ft of Pennsylvanian and Permian age sandstones from 12 well locations. These porosity data and the average porosities of sandstone oil and gas reservoirs within the Anadarko basin of Oklahoma are each compared to

T. C. Hester; J. W. Schmoker

1991-01-01

352

Characterizing Permian upper Minnelusa sandstone reservoirs, Powder River basin, Wyoming, for enhanced oil recovery  

Microsoft Academic Search

Increasing oil production from sandstone reservoirs by enhanced oil recovery (EOR) techniques requires a knowledge of a sandstone's heterogeneity and its control on fluid-flow pathways within the sandstone. Both of these characteristics of upper Minnelusa sandstones are largely a function of sedimentologic and diagenetic effects. Upper Minnelusa sandstones comprise eolian dune, interdune, sabkha, and marine facies. For example, in the

C. J. Schenk; J. W. Schmoker; J. M. Scheffler

1986-01-01

353

Tectonic and eustatic controls on facies distribution in the middle of upper Jurassic, Viking Graben, Norwegian North Sea  

SciTech Connect

The Middle of Upper Jurassic in the Viking Graben area was deposited during an overall transgression. From the lower Toarcian to the base of the cretaceous, there are seven 2nd-order (3-5 m.y.) transgressive-regressive (T/R) facies cycles that are related to regional tectonic events. These cycles dominate facies distribution, appear synchronous, and can be correlated throughout the study area. Local tectonics and sediment supply can modify these cycles. Local tectonics, sediment supply, and position in the T/R facies cycles control development of 3rd-order (0.5-3 m.y.) cycles. Where sediment supply is low, 3rd-order sequences are poorly developed. During a 2nd-order regression, shelfal areas and local highs are often eroded. Third-order sequences have well developed lowstands system-Y tracts (LST) and poorly developed transgressive systems tracts (TST). During 2nd-order transgressions, 3rd-order sequences have enhanced TST, starved HST, and poorly developed LST. Thick, stacked, shoreface sandstones may develop in the TST on terraces or on gently dipping slopes if sediment supply is high. The base of these sequences often shows an abrupt basinward shift in facies followed by backstepping facies. turbidites develop during 3rd-order lowstands when there is a steeply dipping slope and high sediment supply, but their distribution is more limited.

Sneider, J.S.; Vail, P.R. (Rice Univ., Houston, TX (United States)); De Clarens, P. (Elf Aquitaine, Paris (France))

1993-09-01

354

Qingshankou-Putaohua/Shaertu and Jurassic Coal-Denglouku/Nongan total petroleum systems in the Songliao Basin, China  

USGS Publications Warehouse

The Qingshankou-Putaohua/Shaertu petroleum system involves the generation of oil and gas from a mature pod of lacustrine source rock near the center of the Songliao Basin in northeastern China. The primary source rock is the Lower Cretaceous Qingshankou Formation, and a secondary source rock is Member 1 of the Lower Cretaceous Nenjiang Formation. The most productive of six sandstone reservoirs are the Putaohua reservoir (Member 1 of the Lower Cretaceous Yaojia Formation) and the Shaertu reservoir (Members 2 and 3 of the Yaojia Formation and Member 1 of the Nenjiang Formation). Most oil and associated gas generated from the Qingshankou Formation and Nenjiang Formation (Member 1) are trapped in large faulted anticlines, fault blocks, and faulted anticlinal noses in combination with facies-change and (or) diagenetic stratigraphic traps. Two assessment units are defined in the petroleum system: (1) an anticlinal assessment unit; and (2) a subtle-traps assessment unit consisting of (a) anticlinal noses in combination with fault or stratigraphic traps, (b) stratigraphic traps, and (c) unconventional reservoirs. Undiscovered conventional oil and gas resources are expected in both assessment units in small (5?10 million barrels of oil; 30?60 billion ft3 gas) and medium (10?25 million barrels of oil; 60?150 billion ft3 of gas) fields. Also, undiscovered conventional oil and gas resources are expected in several large fields (25?73 million barrels of oil; 150?173 billion ft3 of gas). The Jurassic coal?Dengloukou/Nongan petroleum system involves the generation of natural gas from multiple pods of mature source rock in graben structures at the base of the Songliao Basin. Sandstone and conglomeratic sandstone in the Lower Cretaceous Denglouku Formation and the Lower Cretaceous Quantou Formation are the major reservoir rocks. Most of the known natural gas is trapped in anticlines, anticlinal noses, and fault blocks. This petroleum system is largely unexplored in comparison to the Qingshankou-Putaohua/Shaertu petroleum system and has good potential for undiscovered gas in the structural traps assessment unit. Undiscovered conventional gas is expected in small (30?60 billion ft3 of gas), medium (60?150 billion ft3 of gas), and large (150?395 billion ft3 of gas) fields. The U.S. Geological Survey World Energy Assessment Team (2000) estimated that the Songliao Basin has, at a mean value, about 1.03 billion barrels of undiscovered conventional oil resources and 5.71 trillion ft3 of undiscovered conventional gas resources.

Ryder, Robert T.; Qiang, Jin; McCabe, Peter J.; Nuccio, Vito F.; Persits, Felix

2003-01-01

355

Carbon isotopic constraints on CO 2 degassing in cold-water Geysers, Green River, Utah  

Microsoft Academic Search

Cold-water geysers at Green River, in east central Utah are sourced by natural springs situated along the Little Grand Wash and Salt Wash faults zones, as well as abandoned oil and water wells. The intermittent geysers are driven by degassing of CO2 from CO2-rich waters sourced from the Jurassic Navajo sandstone. Here we discuss use of ?13C analyses of water

N. Assayag; M. Bickle; N. Kampman; J. Becker

2009-01-01

356

Protein and calorie malnutrition among preschool Navajo Indian children, a follow-up.  

PubMed

A follow-up study was conducted on the infant and child-feeding programs to determine the prevalence of protein and calorie malnutrition among preschool Navajo Indian children. These programs were introduced on the reservation in 1968. The numbers of patients admitted to the Public Health Service Indian Hospital, in Tuba City, Arizona, with deficits in weight for their chronological ages, marasmus, and kwashiorkor were compared during two 5-year-periods, 1963 to 1967 and 1969 to 1973. The results show an 18% reduction in the total number of patients under 5 years of age admitted to the hospital and a 39% reduction in the number of patients admitted with deficits in weight for their chronological ages. Marasmus has practically disappeared, with only two cases described since the end of fiscal 1969. The number of cases of kwashiorkor has also decreased by 50%, mainly in the last 4 years. The height and weight data on 1,462 Head Start children from all over the reservation were measured in September 1973, and these measurements were compared with data obtained in September 1967. While they still show a significant deviation from the Boston growth curves, there is a definite improvement from 1967 to 1973. This improvement was especially noticeable in height. Thirty percent of the girls and 30% of the boys fell below the 3rd percentile for Boston in 1967. In 1973, these figures were 11% and 16%, respectively. In the case of the girls in 1973, the numbers below the 3rd percentile are significantly smaller for younger girls than for the older girls, suggesting that the growth retardation occurred in the first 2 years of life, and that the older children had not received the full benefit of the free infant formula feeding programs. This trend, however, was not present in boys. It is concluded that the infant and child feeding programs have contributed to improved growth among Navajo preschool children. At the same time, concern is expressed that these feeding programs will be replaced by a Food Stamp Program and that the gains made will be reversed. Concern is also expressed for the regressive effects of inflation and rising food prices and the effects they will have on the nutritional status of the Navajo people. PMID:818894

Van Duzen, J; Carter, J P; Zwagg, R V

1976-06-01

357

Depositional and diagenetic processes involved in the development of mudstone successions: a multi proxy study of the Lower Jurassic Cleveland Basin (The North Yorkshire coast, England).  

NASA Astrophysics Data System (ADS)

Mud and mudstones are the most abundant (>60%) sediment and sedimentary rock type preserved at and close to the surface of the Earth. They have formed commonly throughout the Phanerozoic and are found in many environments including present-day soils, lake basins, continental shelves, and ocean basins. Mudstones deposited in ancient shelf seas are particularly important as they are very common and significant components of many petroleum systems as sources and seals. In spite of their importance the variability that they exhibit is usually not incorporated into basin-scale facies models as they are assumed to contain little information that is useful in predicting the distribution of reservoir facies. The fundamental mechanisms (physical, chemical and biological) that control the origin of fine-grained sediments in ancient shelf seas is less studied in comparison with other sediments types (e.g. limestones and sandstones). The Middle Jurassic aged succession from the Staithes Sandstone through to the Mulgrave Shale Member (Jet Rock), which is largely continuous and very well-exposed in two locations in the Cleveland Basin, North Yorkshire Coast, England is an ideal natural laboratory to investigate how marginal marine processes evolve into deep marine processes. In the literature, the fundamental controls on lithofacies variability in mudstone-dominated successions preserved in distal shelf environments have been mainly interpreted in terms of varying bottom water oxygen concentrations, primary production and suspension settling. In proximal muddy environments researchers have broadly interpreted lithofacies variability in terms of storm events, tidal currents, etc. These are very different mechanisms. Moreover, these rocks are rarely studied as a whole system; the basinal mudstones are rarely connected up-dip to muddy sandstones and mudstones deposited in the offshore transition and offshore zones. In order to determine the processes responsible for the formation of the individual beds samples were collected from both the proximal sandstone and more basinal mudstone lithofacies. The fabrics present and mineralogy of these materials were visualised by manufacturing unusually large thin sections and imaging the textures present using optical and electron optical methods. A wide diversity of lithofacies present has been found in this section including (intensely bioturbated, silt-bearing, organic matter poor muddy sandstone; bioturbated, clay sized-bearing, silt-rich mudstone; relic, thin-bedded, silt-bearing clay sized-rich mudstone; bioturbated, silt-bearing carbonate cement-rich mudstone; and laminated, clay sized and silt bearing, organic matter rich mudstone). Facies variability in this succession was controlled by the complex interplay between clastic sediment input, physical sediment dispersal, primary production, bioturbation and rates of sedimentation.

Ghadeer, S.; Macquaker, J. H. S.; Hughes, C. R.

2009-04-01

358

Anisotropy of permeability in faulted porous sandstones  

NASA Astrophysics Data System (ADS)

Studies of fault rock permeabilities advance the understanding of fluid migration patterns around faults and contribute to predictions of fault stability. In this study a new model is proposed combining brittle deformation structures formed during faulting, with fluid flow through pores. It assesses the impact of faulting on the permeability anisotropy of porous sandstone, hypothesising that the formation of fault related micro-scale deformation structures will alter the host rock porosity organisation and create new permeability pathways. Core plugs and thin sections were sampled around a normal fault and oriented with respect to the fault plane. Anisotropy of permeability was determined in three orientations to the fault plane at ambient and confining pressures. Results show that permeabilities measured parallel to fault dip were up to 10 times higher than along fault strike permeability. Analysis of corresponding thin sections shows elongate pores oriented at a low angle to the maximum principal palaeo-stress (?1) and parallel to fault dip, indicating that permeability anisotropy is produced by grain scale deformation mechanisms associated with faulting. Using a soil mechanics 'void cell model' this study shows how elongate pores could be produced in faulted porous sandstone by compaction and reorganisation of grains through shearing and cataclasis.

Farrell, N. J. C.; Healy, D.; Taylor, C. W.

2014-06-01

359

Central Appalachian Valley and Ridge Province Cenozoic igneous activity and its relation in space and time with the Late Jurassic rift-to-drift-related alkalic dikes  

NASA Astrophysics Data System (ADS)

A Swarm of Late Jurassic alkalic intrusions, geographically limited mainly to the Augusta County in western Virginia has been studied geochemically. These dykes were emplaced along a northwest-southeast cross-strike basement fracture zone during Mesozoic extension. However, not all igneous rocks in Virginia are Jurassic; published K-Ar ages already suggested an Eocene age activity around Monterey, VA. We systematically sampled and studied these rocks geochemically and used the Ar-Ar dating technique to define a more precise age for this youngest volcanic activity East of the Mississippi. The younger igneous bodies have traditionally been interpreted as intrusive bodies representing old plumbing systems of eroded volcanic centers. This hypothesis is based on studies of aphanitic to porphyritic and occasionally vesicular hard rocks from quarries and road cuts. Pyroclastic deposits have mainly been neglected during theses earlier studies. However additional petrographic studies of volcanic sediments are able to shed light not only on the volcanic nature of these pyroclastic rocks but also on eruption mechanisms and magma crust interactions. Our petrographic studies indicate that these volcanic sediments contain different clasts of igneous and sedimentary country rocks (sandstones and limestones of different formations), fresh glass shards and crystals of predominantly pyroxene, hornblende and micas. A previously unmapped, massive, m-thick andesitic pyroclastic deposit has been studied in detail to shed light on the formation of theses volcanic sediments. Field relations and observations (e.g. denser rock fragments are enriched in the lower part of the sequence and bedding is largely parallel to the present topography) are consistent with a massive welded ignimbrite. As a result, surface erosion after the eruption must be less significant than previously believed and some rocks are clearly volcanic in nature. Petrogenetically the Jurassic magmas are much more alkalic and particularly K-rich, and thus have all the characteristics of delamination magmas. This confirms that delamination seems a substantial process during the rift to drift transition. After Jurassic delamination of lithosphere below Virginia hot geochemically depleted asthenosphere was transformed into lithosphere by lithospherization. This newly formed lithosphere has later been the mantle source of the Cenozoic volcanic activity. As a result, the suggested geodynamic model is not only important to the petrology community but also to understand the local geomorphology, seismicity and presence of hot springs.

Meyer, R.; Schultz, L.; Hendriks, B. W.; Harbor, D. J.; Connors, C. D.

2011-12-01

360

Weatherization assistance program: Final monitoring report for Arizona; California; the Navajo Nation; Nevada  

SciTech Connect

Stroud, Inc., was awarded a contract by the Department of Energy San Francisco Operations Office (DOE-SAN) to evaluate the weatherization program for selected grantees and subgrantees in Arizona, California, the Navajo Nation, and Nevada. The provisions of the contract specified an initial year and renewable optional periods of two (2) additional years. This report covers the monitoring of grantees and subgrantees for the first option year, or what is the second year of the contract. The first two (2) weeks of the second year's activities were devoted to scheduling the agencies to be monitored. The actual field monitoring began on October 14, 1986, and was completed on May 22, 1987. During this seven-month period, thirty-five (35) agencies were visited and evaluated under this contract.

Not Available

1987-07-01

361

A "Role-play" Activity for Teaching about Uranium Mining on the Navajo Nation  

NSDL National Science Digital Library

This activity uses an assortment of digital resources relevant to exploring resource development on Native American lands. The activity is based on a website that uses an Earth System approach to help students understand how Native American lands have been impacted by resource development. In the role-playing exercise, students are assigned one of several roles, including consulting geologists, the mining industry, tribal elders and public health officials. Each student uses the web-based learning materials to research the issue from the perspective of their role. This type of exercise could also be used as a debate by dividing a class into groups that play the roles of the Navajo people and the Federal Government.

Klauk, Erin

362

Cleanup of inactive Uranium Mill Tailings Sites in the Navajo Nation  

SciTech Connect

The U.S. Congress passed the Uranium Mill Tailings Radiation Control Act (UMTRCA) in 1978 to address potential and significant radiation health hazards to the public from active and inactive mill operations. Title I to the UMTRCA identified sites to be designated for remedial action. These include four uranium mill tailings remedial action (UMTRA) sites in the Navajo Nation. These sites are located in Shiprock, New Mexico; Tuba City, Arizona; Cane Valley, Arizona; and Halchita, Utah. The U.S. Department of Energy (DOE) was directed to select and execute a plan of remedial action that provides long-term stabilization and control of radioactive materials and satisfies the U.S. Environmental Protection Agency standards and other applicable laws and regulations.

Martin, B.

1994-12-31

363

Direct chemical evidence for eumelanin pigment from the Jurassic period  

PubMed Central

Melanin is a ubiquitous biological pigment found in bacteria, fungi, plants, and animals. It has a diverse range of ecological and biochemical functions, including display, evasion, photoprotection, detoxification, and metal scavenging. To date, evidence of melanin in fossil organisms has relied entirely on indirect morphological and chemical analyses. Here, we apply direct chemical techniques to categorically demonstrate the preservation of eumelanin in two > 160 Ma Jurassic cephalopod ink sacs and to confirm its chemical similarity to the ink of the modern cephalopod, Sepia officinalis. Identification and characterization of degradation-resistant melanin may provide insights into its diverse roles in ancient organisms.

Glass, Keely; Ito, Shosuke; Wilby, Philip R.; Sota, Takayuki; Nakamura, Atsushi; Bowers, C. Russell; Vinther, Jakob; Dutta, Suryendu; Summons, Roger; Briggs, Derek E. G.; Wakamatsu, Kazumasa; Simon, John D.

2012-01-01

364

Tanzania wildcats to evaluate Jurassic Mandawa salt basin  

SciTech Connect

After 5 years of stagnant exploration in East Africa, Canadian independent Tanganyika Oil Co. of Vancouver, B.C., will drill two wildcats in Tanzania to evaluate the hydrocarbon potential of the coastal Jurassic Mandawa salt basin. Mita-1, spudded around Oct. 1, will be drilled to about 7,000 ft, East Lika-1 will be drilled in early December 1996 to approximately 6,000 ft. The two wells will test different structures and play concepts. The paper describes the exploration history, source rock potential, hydrocarbon shows, potential reservoir, and the prospects.

Nagati, M. [Tanganyika Oil Co., Dubai (United Arab Emirates)

1996-10-07

365

Unusual occurrence of some sedimentary structures and their significance in Jurassic transgressive clastic successions of Northern Ethiopia  

NASA Astrophysics Data System (ADS)

Mesozoic sedimentary successions produced by marine transgression and regression of sea in northeastern part of Africa are well preserved in Mekelle basin of Ethiopia. Here, a typical second order sequence is well developed and preserved overlying the Precambrian basement rocks or patchy Palaeozoic sedimentary successions. Initiation of Mesozoic sedimentation in Mekelle basin has started with deposition of Adigrat Sandstone Formation (ASF). It is a retrogradational succession of siliciclastics in coastline/beach environment due to transgression of sea from southeast. ASF is followed by Antallo Limestone Formation (ALF)- an aggradational succession of carbonates in tidal flat environment; Agula Shale/Mudstone Formation (AMF); and Upper/Ambaradom Sandstone Formation (USF)- a progradational succession formed during regression in ascending order (Dubey et al., 2007). AMF is deposited in a lagoonal evaporatic environment whereas USF in a fluvial coastal margin. ASF is an aggregate of cyclically stacked two lithologies ASF1 and ASF2 produced by sea-level rise and fall of a lower order mini-cycle. ASF1 is a thick, multistoried, pink to red, friable, medium to fine grained, cross-bedded sandstone deposited in a high energy environment. ASF2 is a thin, hard and maroon colored iron-rich mudstone (ironstones) deposited in a low energy environment. ASF1 has resulted during regressive phase of the mini-cycle when rate of sedimentation was extremely high due to abundant coarser clastic supply from land to the coastal area. On the other hand, ASF2 has resulted during transgressive phase of the mini-cycle which restricted the supply of the coarser clastic to the coastal area and deposited the muddy ferruginous sediments in low energy offshore part of the basin where sedimentation rate was very low. Apart from these two major lithologies, there are also few other minor lithologies like fine-grained white sandstone, carbonate (as bands), claystone and mudstone present in ASF. ASF is a well developed lithostratigraphic unit of northern Ethiopia and represents the Jurassic transgressive clastic succession of Mekelle basin. The physical and biogenic sedimentary structures reported in this paper are observed from the terminal part of ASF. Their occurrence is unusual, rare, unknown so far and unreported. It includes (i) mud cracks (including their casts filled with overlying lithology) representing subaerial exposure which is unusual during transgressive phase, (ii) vertical traces of Skolithos burrows in ASF2 produced by suspension feeders in high energy environment of deposition (Dubey et al., 2007), (iii) tiny bivalve moulds and casts (external- and internal-moulds) of body fossils, and (iv) elliptical negative epirelief (potato shaped empty depressions - external moulds of eggs or nodules?). Fifty two such randomly oriented external moulds are noticed within 2 m2 area on an upper bedding plane of thin, white and fine- grained sandstone. Their in- fills are missing/removed as they are present on a gently dipping bed. Therefore, it is difficult to ascertain their biogenic (egg) or abiogenic (nodule) origin. Their detail investigation is under progress. Since ASF developed during marine transgression, presence of mud cracks in its terminal part indicates subaerial exposure. This provides suitable sites for nesting eggs (reptile?) in wet sands. Removal of such preserved eggs can provide potato depressions. Though it is difficult to relate these moulds to the eggs because of the missing in-fills, their shape, size and restricted occurrence supports biogenic origin. Reference Dubey, N., Bheemalingeswara, K. and Tadesse, N. (2007). Sedimentology and lithostratigraphy of the Mesozoic successions of Mekelle Basin, Ethiopia, Norteastern Africa. Geophysical Research Abstracts, Vol.9, 11471. (SRef-ID: 1607-7962/gra/EGU2007-A-11471).

Dubey, N.; Bheemalingeswara, K.

2009-04-01

366

LABORATORY EXPERIMENTS ON ABRASION OF SANDSTONES BY ICE  

Microsoft Academic Search

Small blocks of sandstone were eroded by sliding under ice in a harmonic and a constant motion. The harmonic motion caused ice accretion on the rock and an ice\\/ice sliding surface. Addition of a dense layer of sand grains to the ice produced rock abrasion. Sliding of a cylinder of sandstone with constant angular velocity under ice eroded a pit

H. LISTER; A. PENDHNGTON; J. CHORLTON

367

Modelling of simulated reservoir sandstones clay precipitation within  

Microsoft Academic Search

The purpose of this study was to investigate whether a previously developed computer model, named Pore-Cor, could simulate the subtle changes in void space dimensions which occur during the artificial deposition of small amounts of illite and kaolinite within Fontainebleau sandstone. Clay precipitation was carried out by placing a sandstone plug in a gold capsule, with an alu- minosilicate gel,

G. Peter Matthews; Cathy J. Ridgway; Joe S. Small

368

Sandstone porosity as a function of thermal maturity  

USGS Publications Warehouse

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

Schmoker, J. W.; Gautier, D. L.

1988-01-01

369

Study on the texture of a low permeable sandstone reservoir  

Microsoft Academic Search

With the Maling oil field as an example, this study presents the origin of the pore texture of a low permeability sandstone reservoir and its influence on developmental results. Reservoirs in the Yan an Formation are channel sandstones which were intensively reformed by diagenesis. Their permeability is only 3 to 100 md, and porosity is 10 to 18%. Analysis by

Zhu

1982-01-01

370

Pediatric motor vehicle related injuries in the Navajo Nation: the impact of the 1988 child occupant restraint laws  

PubMed Central

Background: Navajo motor vehicle mortality is the highest among the 12 Indian Health Service (IHS) administrative areas. In July 1988, the Navajo Nation enacted a primary enforcement safety belt use and a child restraint law. Objective: Assess the impact of the laws on the rate and severity of pediatric (0–19 years) motor vehicle injury resulting in hospitalizations in the Navajo Nation. Methods: Hospitalizations associated with motor vehicle related injury discharges were identified by International Classification of Diseases, 9th revision, CM E codes, 810–825 (.0,.1) from the Navajo IHS hospital discharge database. Age specific rates for the period before the law, 1983–88, were compared with those after enactment and enforcement, 1991–95. Severity of injury, measured by the abbreviated injury scale (AIS) score and new injury severity score (NISS), was determined with ICDMAP-90 software. Wilcoxon rank sum and ?2 tests were used for analysis. Results: Discharge rates (SE) for motor vehicle injury (per 100 000) decreased significantly in all age groups: 0–4 years (62 (7) to 28 (4)), 5–11 years (55.3 (6) to 26 (4)), and 15–19 years (139 (14) to 68 (7)); p=0.0001. In children 0–4 years, the median AIS score decreased from 1.5 (1,3) (25th, 75th centile) to 1 (1,2), p=0.06, and the median NISS decreased from 3.5 (1,9) to 2 (1,5), p=0.07. The proportion of children with NISS scores >4 decreased significantly for the 0–4 year age group (p=0.03). Conclusions: Concurrent with enactment of the Navajo Nation occupant and child restraint laws there was a reduction in the rate of motor vehicle related hospital discharges for children. Severity of injury declined in very young Navajo children. The effect of enactment and enforcement of this Native American child occupant restraint law may serve as an example of an effective injury control effort directed at Native American children.

Phelan, K; Khoury, J; Grossman, D; Hu, D; Wallace, L; Bill, N; Kalkwarf, H

2002-01-01

371

TRIASSIC-JURASSIC BOUNDARY ON THE SOUTHERN MARGIN OF TETHYS: IMPLICATIONS OF FACIES, TECTONICS AND VOLCANISM  

Microsoft Academic Search

The facies changes, tectonics and magmatism across the Triassic-Jurassic boundary in the southern Tethyan margin have been studied in Egypt, Sudan, Jordan and Saudi Arabia. In Saudi Arabia and Jordan an unconformable contact is recognized between the Upper Triassic and Lower Jurassic rocks. This unconformity surface is marked by the truncation of the fluvial clastics of the uppermost Triassic before

MOHAMED A. KHALIFA

372

A new Late Jurassic species of the rare synechodontiform shark, Welcommia (Chondrichthyes, Neoselachii)  

Microsoft Academic Search

A new Jurassic species of the very rare and incompletely known synechodontiform shark, Welcommia, is described. The new species, Welcommia cappettai, is represented only by a single tooth, precluding reconstruction of its dentition in detail. Nevertheless, this specimen\\u000a provides sufficient information and characteristics to establish its taxonomic status. Welcommia cappettai n. sp. occurs in the middle Oxfordian (Upper Jurassic) of

Stefanie KlugJurgen Kriwet; Jürgen Kriwet

2010-01-01

373

Jurassic hot spring deposits of the Deseado Massif (Patagonia, Argentina): Characteristics and controls on regional distribution  

Microsoft Academic Search

The Deseado Massif, Santa Cruz Province, Argentinean Patagonia, hosts numerous Middle to Late Jurassic age geothermal and epithermal features represented by siliceous and calcareous chemical precipitates from hot springs (sinters and travertines, respectively), hydrothermal breccias, quartz veins, and widespread hydrothermal silicification. They indicate pauses in explosive volcanic activity, marking the final stages in the evolution of an extensive Jurassic (ca.

Diego M. Guido; Kathleen A. Campbell

2011-01-01

374

A new early Jurassic pteridosperm fructification from Queensland  

NASA Astrophysics Data System (ADS)

An open, biseriate seed-bearing fructification, accompanied by its much more numerous male counterpart, is described as Knezourocarpon narangbaensis. Fructifications are open, catkin-like structures and are considered likely to belong to Pteridospermophyta. Most specimens are fairly complete and occur along with poorly preserved fragments resembling fern and equisetalean leaves. They are preserved in fine-grained argillaceous sandstone in the upper Landsborough Sandstone of the southern Nambour Basin in southeast Queensland, Australia, and are of likely Toarcian age. The likely sedimentary setting is within a levee complex, which was associated with a braided river system, and it is suggested that the fructifications' host plants formed a levee to proximal flood plain scrub.

Pattemore, G. A.

2000-07-01

375

Petrology and geochemistry of the Late Jurassic calc-alkaline series associated to Middle Jurassic ophiolites in the South Apuseni Mountains (Romania)  

Microsoft Academic Search

Abstract In the South Apuseni Mountains (SAM), Romania, Jurassic calc-alkaline magmatic series occur in association with Jurassic ophiolites within a narrow belt that marks the boundary,between,the Eurasian and Adria Paleozoic conti- nental margins. This association of magmatic series has been previously reported,as a single ophiolitic sequence,by many authors. Calc-alkaline rocks include volcanic and intrusive rocks and, along with associated ophiolites,

Ionel Nicolae; Emilio Saccani

2003-01-01

376

New isotopic evidence for the origin of groundwater from the Nubian Sandstone Aquifer in the Negev, Israel  

USGS Publications Warehouse

The geochemistry and isotopic composition (H, O, S, Osulfate, C, Sr) of groundwater from the Nubian Sandstone (Kurnub Group) aquifer in the Negev, Israel, were investigated in an attempt to reconstruct the origin of the water and solutes, evaluate modes of water-rock interactions, and determine mean residence times of the water. The results indicate multiple recharge events into the Nubian sandstone aquifer characterized by distinctive isotope signatures and deuterium excess values. In the northeastern Negev, groundwater was identified with deuterium excess values of ???16???, which suggests local recharge via unconfined areas of the aquifer in the Negev anticline systems. The ??18OH2O and ??2H values (-6.5??? and -35.4???) of this groundwater are higher than those of groundwater in the Sinai Peninsula and southern Arava valley (-7.5??? and -48.3???) that likewise have lower deuterium excess values of ???10???. Based on the geochemical differences between groundwater in the unconfined and confined zones of the aquifer, a conceptual geochemical model for the evolution of the groundwater in the Nubian sandstone aquifer has been reconstructed. The isotopic composition of shallow groundwater from the unconfined zone indicates that during recharge oxidation of pyrite to SO4 (??34SSO4 ???-13???; ??18OSO4 ???+7.7???) and dissolution of CaCO3 (87Sr/86Sr ???0.70787; ??13CDIC = -3.7???) occur. In the confined zone of the aquifer, bacterial SO4 reduction removes a significant part of dissolved SO42 -, thereby modifying its isotopic composition (??34SSO4 ???-2???; ??18OSO4 ???+8.5???) and liberating dissolved inorganic C that contains little or no radiocarbon (14C-free) with low ??13CDIC values (<-12???). In addition to local recharge, the Sr and S isotopic data revealed contribution of external groundwater sources to the Nubian Sandstone aquifer, resulting in further modifications of the groundwater chemical and isotopic signatures. In the northeastern Negev, it is shown that SO4-rich groundwater from the underlying Jurassic aquifer contributes significantly to the salt budget of the Nubian Sandstone aquifer. The unique chemical and isotopic composition of the Jurassic groundwater (??34SSO4 ??? +14???; ??18OSO4 ??? 14???; 87Sr/86Sr ???0.70764) is interpreted as reflecting dissolution of Late Triassic marine gypsum deposits. In the southern Arava Valley the authors postulate that SO4-rich groundwater with distinctively high Br/Cl (3 ?? 10-3) low 87Sr/86Sr (0.70734), and high ??34SSO4 values (+15???) is derived from mixing with underlying brines from the Paleozoic units. The radiocarbon measurements reveal low 14C activities (0.2-5.8 pmc) in both the northeastern Negev and southern Arava Valley. Taking into account dissolution of carbonate rocks and bacterial SO4 reduction in the unconfined area, estimated mean residence times of groundwater in the confined zone in the northeastern Negev are on the order of 21-38 ka, which suggests recharge predominantly during the last glacial period. The 14C signal in groundwater from the southern Arava Valley is equally low but due to evidence for mixing with external water sources the residence time estimates are questionable. ?? 2007 Elsevier Ltd. All rights reserved.

Vengosh, A.; Hening, S.; Ganor, J.; Mayer, B.; Weyhenmeyer, C. E.; Bullen, T. D.; Paytan, A.

2007-01-01

377

Triassic-Jurassic mass extinction as trigger for the Mesozoic radiation of crocodylomorphs  

PubMed Central

Pseudosuchia, one of the two main clades of Archosauria (Reptilia: Diapsida), suffered a major decline in lineage diversity during the Triassic–Jurassic (TJ) mass extinction (approx. 201 Ma). Crocodylomorpha, including living crocodilians and their extinct relatives, is the only group of pseudosuchians that survived into the Jurassic. We reassess changes in pseudosuchian morphological diversity (disparity) across this time interval, using considerably larger sample sizes than in previous analyses. Our results show that metrics of pseudosuchian disparity did not change significantly across the TJ boundary, contrasting with previous work suggesting low pseudosuchian disparity in the Early Jurassic following the TJ mass extinction. However, a significant shift in morphospace occupation between Late Triassic and Early Jurassic taxa is recognized, suggesting that the TJ extinction of many pseudosuchian lineages was followed by a major and geologically rapid adaptive radiation of crocodylomorphs. This marks the onset of the spectacularly successful evolutionary history of crocodylomorphs in Jurassic and Cretaceous ecosystems.

Toljagic, Olja; Butler, Richard J.

2013-01-01

378

Triassic-Jurassic mass extinction as trigger for the Mesozoic radiation of crocodylomorphs.  

PubMed

Pseudosuchia, one of the two main clades of Archosauria (Reptilia: Diapsida), suffered a major decline in lineage diversity during the Triassic-Jurassic (TJ) mass extinction (approx. 201 Ma). Crocodylomorpha, including living crocodilians and their extinct relatives, is the only group of pseudosuchians that survived into the Jurassic. We reassess changes in pseudosuchian morphological diversity (disparity) across this time interval, using considerably larger sample sizes than in previous analyses. Our results show that metrics of pseudosuchian disparity did not change significantly across the TJ boundary, contrasting with previous work suggesting low pseudosuchian disparity in the Early Jurassic following the TJ mass extinction. However, a significant shift in morphospace occupation between Late Triassic and Early Jurassic taxa is recognized, suggesting that the TJ extinction of many pseudosuchian lineages was followed by a major and geologically rapid adaptive radiation of crocodylomorphs. This marks the onset of the spectacularly successful evolutionary history of crocodylomorphs in Jurassic and Cretaceous ecosystems. PMID:23536443

Toljagic, Olja; Butler, Richard J

2013-06-23

379

Comparison of sandstone diagenesis and reservoir development within two lower Cretaceous J sandstone fields, Denver basin, Colorado  

SciTech Connect

Thermal history reconstruction indicates Wattenberg field sandstones were buried deeper and were subjected to significantly higher heat flows than Kachina field sandstones. The greater burial temperature and pressure result in a higher degree of sediment compaction, fracturing of reservoir rocks, and generally more chert and polycrystalline quartz cements than Kachina field reservoir rocks.

Higley, D.K. (Geological Survey, Lakewood, CO (USA))

1989-09-01

380

Comparison of sandstone diagenesis and reservoir development within two lower Cretaceous J sandstone fields, Denver basin, Colorado  

Microsoft Academic Search

Thermal history reconstruction indicates Wattenberg field sandstones were buried deeper and were subjected to significantly higher heat flows than Kachina field sandstones. The greater burial temperature and pressure result in a higher degree of sediment compaction, fracturing of reservoir rocks, and generally more chert and polycrystalline quartz cements than Kachina field reservoir rocks.

Debra K. Higley

1989-01-01

381

Durabilité chimique de l'uraninite précipitée sur le grès du Navajo  

Microsoft Academic Search

Batch and sand column experiments were conducted with sandstone and ground water to investigate the oxidation of uraninite. Uraninite and mackinawite precipitated by indigenous bacteria in contaminated ground water from a former uranium mill tailings site near Tuba City, Arizona, USA. Leaching of a sand column containing uraninite and mackinawite by oxygen-saturated uncontaminated ground water from the same site showed

Abdesselam Abdelouas; Werner Lutze; Eric Nuttall

1998-01-01

382

Power, Prayers, and Protection: Comb Ridge as a Case Study in Navajo Thought  

ERIC Educational Resources Information Center

Beginning in 2005, a five-year survey of cultural resources began to unfold in southeastern Utah along a prominent sandstone rock formation known as Comb Ridge. This visually dramatic monocline stretches a considerable distance from the southwestern corner of Blue Mountain (Abajos) in Utah to Kayenta, Arizona, approximately one hundred miles to…

McPherson, Robert S.

2010-01-01

383

The Jurassic of Svalbard, Sedimentology, Stratigraphy and Paleontology  

NASA Astrophysics Data System (ADS)

During the Mesozoic the landmass now known as Svalbard drifted from 45oN to 65oN. The average global temperature was significantly higher, disabling the formation of icecaps at the poles, resulting in a higher sea-level. At the time the location now known as Svalbard was covered by a shallow ocean and mostly marine, organic rich, black shales, interrupted by possibly deltaic sediments were deposited. These sediments are rich in invertebrate fossils. A general description of the Agardhfjellet formation, spanning the middle to upper Jurassic, was made by Dypvik in 1991. Wierzbowski (1989) described some ammonites in detail from the Kimmeridgian. It is not known if the fauna extends further up or down in the formation. Since 2004 the Museum of Natural History of Oslo has been active in Spitsbergen Svalbard. Extensive and detailed sedimentological and stratigraphic research was never conducted as the focus lay on vertebrate fossils. A detailed sedimentological analysis, description and correlation to other Jurassic Formations (such as the Kimmeridge Shales, Hekkingen Formation and draupne Formation) is essential to better understand the circumstances where the black organic-rich shales (a highly potential source rock) were deposited in and to be able to predict their occurrences. Included in this description is taxonomy, taphonomy and the stratigraphic development of invertebrate fauna to pinpoint the age of the sediments.

Koevoets, Maayke; Hammer, Øyvind

2014-05-01

384

Testing Iberian kinematics at Jurassic-Cretaceous times  

NASA Astrophysics Data System (ADS)

reconstructions of Iberia at the Mesozoic are still a matter of debate. The incompatibility between kinematic models and paleomagnetic data older than 120 Ma is a major problem for which no cause has yet been determined. Here we use a new method to investigate the origin of this misfit. We solve the inverse problem of finding the Euler poles that fit paleomagnetic poles with the Global Apparent Polar Wander Path (GAPWP) and then test their implications on Iberian reconstructions. We show that Iberian poles from the Early Cretaceous (mean poles for 123 and 130 Ma) are incompatible with the GAPWP, bringing into question their validity. Contrarily, Late Jurassic data (mean pole at 151 Ma) are compatible with the GAPWP and, thus, can be considered reliable. Based on these results, we propose a new magnetic reconstruction of Iberia and surrounding plates at ~150 Ma (M22 anomaly). This work provides new constraints for the kinematic evolution of Iberia during Jurassic-Cretaceous. However, the development of a detailed and consensual model for the kinematic evolution of Iberia is dependent on the acquisition of new, high-quality paleomagnetic data and a reevaluation of seafloor magnetic anomalies.

Neres, M.; Miranda, J. M.; Font, E.

2013-09-01

385

Isotopic constraints on the petrogenesis of jurassic plutons, Southeastern California  

USGS Publications Warehouse

The 165 Ma Eagle Mountain intrusion is a heterogeneous, enclave-bearing, metaluminous remnant of the Cordilleran Jurassic arc that cuts regionally metamorphosed pre-Mesozoic rocks in the southeastern Mojave Desert of California. The main phase of the intrusion consists of granodiorite to tonalite host facies, diorite mixed facies, and homogeneous monzogranite facies. The host facies contains microdiorite enclaves interpreted as intermingled masses of mafic magma. Late-phase leucogranite stocks cut the main phase. Mineral equilibria indicate emplacement at ???6.5 km depth, with solidus temperatures ranging from 760??C for diorite to 700??C for felsic granodiorite. Although uniform radiogenic-isotope compositions (Sri = 0.7085, ???Ndi = -9.4) suggest derivation from a single source, no known source has the composition required. A hybrid source is proposed, consisting of various proportions of juvenile mantle and recycled lower crust. Calculations indicate that the source of the Eagle Mountain intrusion comprised >60% juvenile mantle and <40% recycled crust. On the basis of their isotopic compositions, other mafic Jurassic plutons in the region were derived from sources containing different proportions of mantle and crustal components.

Mayo, D. P.; Anderson, J. L.; Wooden, J. L.

1998-01-01

386

Geochemical features of metabasic rocks from an Early to Middle Jurassic Accretionary Complex (Refahiye metamorphics, Eastern Pontides, NE Turkey): Implications for Late Jurassic-Early Cretaceous magmatic lull  

NASA Astrophysics Data System (ADS)

The Refahiye metamorphics (Eastern Pontides, NE Turkey) represent a metamorphosed accretionary complex of Early to Middle Jurassic age and occur as an interleave between coeval ophiolite. This Early to Middle Jurassic metamorphics and ophiolites are bound by a Permo-Triassic accretionary complex in the north and a Late Cretaceous accretionary complex in the south. The Refahiye metamorphics are made up of greenschist, marble, serpentine, phyllite and subordinately amphibolite, micaschist, eclogite and metachert knockers. The Jurassic and Late Cretaceous accretionary complexes in Eastern Mediterranean are related to the consumption of a Mesozoic ocean, the so-called Neo-Tethys. Regional geology in the Eastern Pontides indicate that the Early to Middle Jurassic and Late Cretaceous times correspond to volumious igneous activity, while Late Jurassic and Early Cretaceous time to an igneous lull. Here we present whole-rock geochemical data on metabasic rocks from the Refahiye accretionary complex, and discuss these data in terms of accreted material and its implications for the Jurassic evolution of the Eastern Pontides. All the metabasic rocks are well recrystallized, free of any relict texture and are variably hydrated (LOI ~ 1.3-5.1 wt%). Some samples are characterized by the unusually high-Al2O3 contents (up to 20.8 wt%) suggestive of derivation from high-Al basalts. Geochemically three distinct metabasic group are distinguished, on the basis of fluid immobile HFSEs and REEs. Group I is characterized by moderately to strongly fractionated REE patterns [(La/Yb)cn ~8-18], absence of any Nb-Ta anomaly in multi element variation diagrams and high Ti and low Zr/Nb ratios (3.68-5.72), corresponding to unorogenic alkaline basalts (ocean island basalt). Group II characterized by moderately fractionated REE ratios [(La/Yb)cn ~0.6-2.6], absence of any Nb-Ta anomaly, resembling unorogenic tholeiitic basalts (E and N-MORB). Group III on the other hand, displays unfractionated, nearly flat REE patterns [(La/Yb)cn ~0.6-1.1], negative Nb-Ta anomaly and enormously high Zr/Nb values (38-62), corresponding to orogenic tholeeitic basalts. These data indicate accretion of unorogenic alkaline and tholeiitic basalts similar to those in seamounts, MORB and IAB during the Early to Middle Jurassic subduction. This together with widespread Early to Middle Jurassic magmatism in Eastern Pontides and Crimea and absence in the southern Menderes-Taurus continental block, conclusively indicate for a northvergent subduction. On the basis of the general absence of a Middle to Upper Jurassic unconformity, we tentatively ascribe the Late Jurassic-Early Cretaceous magmatic lull to the accretion of large submarine topographic highs to the subduction zone.

Göçmengil, G.; Topuz, G.; Çelik, Ö. F.; Alt?nta?, Ä.°. E.; Özkan, M.

2012-04-01

387

Role of clay minerals in the physicomechanical deterioration of sandstone  

NASA Astrophysics Data System (ADS)

Extensive weathering suffered by sandstone in natural outcrops as well as in historical buildings could be attributed among other mechanisms to the action of wetting and drying cycles. We have recently shown how to quantify the stresses generated during such cycles to determine whether damage can take place. This procedure is further developed in this paper and applied to the Tarifa sandstone, a sandstone with a 7 wt % content of clay minerals and used in the main façade of the church of San Mateo in Tarifa (Cádiz, Spain) for which the relevant material properties are measured. It is shown that tensile stresses during drying can cause cracking of thin elements and that shear forces can cause buckling of wetted surfaces more generally, eventually resulting in scaling and/or contour scaling. These predictions are supported by visual observations on the monument showing degradation patterns characteristic of those types of damage. Similar weathering forms have been observed in natural sandstone landscapes. Application of swelling inhibitors (e.g., cationic surfactants) that selectively adsorb on the clay basal planes, results in a substantial swelling reduction. This confirms that the swelling clays typically present in sandstone are pivotal for its weathering and indicates that swelling inhibitors are a potentially valuable treatment to prevent or minimize damage to stone. The circumstances that would lead to weathering are discussed in relation to sandstone material properties in the wet and dry state. Clay-bearing stones are shown to exhibit softening during wetting, as well as viscoelastic stress relaxation, which is expected to limit the extent of damage. These results may aid in the better understanding of sandstone weathering both in nature and in urban environment and may help develop conservation methods to mitigate wetting/drying damage in ornamental sandstone or to prevent pore plugging in reservoir sandstones.

JiméNez-GonzáLez, Inmaculada; RodríGuez-Navarro, Carlos; Scherer, George W.

2008-06-01

388

Developments in gas reservoir research with applications to tight sandstones  

SciTech Connect

Research on tight sandstone formations emphasizes the importance of applicability to overall reservoir geology based on geologic similarities, particularly in the areas of transferring hydraulic fracturing techniques. Examples of tight gas sandstone formations are the Travis Peak and the Corcoran-Cozzette deposits. Where gas recovery depends upon the conductivity of a propped hydraulic fracturing through a tight sandstone, the magnitude of the recoverable resource base has both technical and economic uncertainties. Future geologic research will continue to gain insight into the degree of interconnectedness within the reservoir of production levels, gas/water ratios, reservoir pressure, and other parameters. 20 references, 1 table.

Finley, R.J.

1985-06-01

389

Geology and ore deposits of the Monument Valley area, Apache and Navajo counties, Arizona: Part II  

USGS Publications Warehouse

In 1951 and 1952, the U.S. Geological Survey conducted a program of uranium investigations and geologic mapping in the Monument Valley area, Apache and Navajo Counties, Ariz. About 700 square miles were mapped on the Navajo Indian Reservation. A resource appraisal of the area was an inherent part of the program, and is detailed in this report. Production of vanadium and uranium is from two areas, the Monument No. 1 mine area in Navajo County, and the Monument No. 2 mine area in Apache County. In the period 1942-53 about 200,300 tons of ore was produced from these two areas. This ore yielded about 1,700,000 pounds of U3O8 and about 6,500,000 pounds of V2O5. The grade ranged from 0.15 percent U3O8 to 0.60 percent U3O8, and from 0.38 percent V2O5 to 3.02 percent V2O5. The vanadium-uranium ratio is about 4:1. The ore deposits are composed principally of the hydrous calcium-uranium vanadate tyuyamunite in basal channel sediments of the Shinarump member off the Chinle formation. Four types of ore bodies are present: (1) rods, (2) tabular ore bodies, (3) corvusite-type ore bodies, and (4) rolls. The reserves of uranium- and vanadium-bearing material are classed as measured, indicated, inferred, and potential. The reserves are further divided into three grade classes for material 1 foot or more thick: (1) 0.10 percent U3O8 and 1.00 percent V2O5 and above; (2) 0.05 percent U3O8 and 0.50 percent V2O5 and less than 0.10 percent U3O8 and 1.00 percent V2O5; and (3) 0.01 percent U3O8 and 0.10 percent V2O5 and less than 0.05 percent U3O8 and 0.05 percent V2O5. Measured reserves as of June 1953, in the Monument Valley area, Arizona, (all in the Monument No. 2 mine) total about 36,000 tons. Indicated reserves in the first grade class amount to about 62,000 tons. In this same grade class inferred reserves total about 3,000,000 tons. In the second grade class indicated and inferred reserves amount to about 2,000,000 tons. Inferred reserves in the third grade class total about 345,000 tons of mineralized material. Potential reserves in all grade classes for the Monument Valley area amount to about 13,000,000 tons. It is recommended that an extensive exploration program be carried out in the Monument Valley area, Arizona. This program would consist of two phases. The first phase would involve a geophysical survey of selected channels and would have at its principal objective the delineation of the trend, length, width, and depth of scour of the channels. The second phase would consist of a diamond-drilling program that would make use of the data secured by the geophysical survey. This drilling program would have as one of its principal objectives the determination of which channels are most likely to contain ore bodies. Once the favorable channels are discovered, the drilling program could be carried on most suitably by private operators.

Witkind, I. J.; Thaden, R. E.

1958-01-01

390

Influence of petrographic parameters on geotechnical properties of tertiary sandstones from Taiwan  

Microsoft Academic Search

While tunneling through Tertiary sandstones in Taiwan, tunnel squeezing occurred in some of the sandstones (e.g., Mucha Tunnel and Chungho Tunnel in northern Taiwan), but not in all of them. This phenomenon indicates that the geotechnical properties of Tertiary sandstones differ from one sandstone to another, and further characterization is of interest. Laboratory experiments were conducted to explore the geotechnical

F. S Jeng; M. C Weng; M. L Lin; T. H Huang

2004-01-01

391

Direct evidence of hybodont shark predation on Late Jurassic ammonites  

NASA Astrophysics Data System (ADS)

Sharks are known to have been ammonoid predators, as indicated by analysis of bite marks or coprolite contents. However, body fossil associations attesting to this predator-prey relationship have never been described so far. Here, I report a unique finding from the Late Jurassic of western France: a complete specimen of the Kimmeridgian ammonite Orthaspidoceras bearing one tooth of the hybodont shark Planohybodus. Some possible tooth puncture marks are also observed. This is the first direct evidence of such a trophic link between these two major Mesozoic groups, allowing an accurate identification of both organisms. Although Planohybodus displays a tearing-type dentition generally assumed to have been especially adapted for large unshelled prey, our discovery clearly shows that this shark was also able to attack robust ammonites such as aspidoceratids. The direct evidence presented here provides new insights into the Mesozoic marine ecosystem food webs.

Vullo, Romain

2011-06-01

392

Extreme adaptations for aquatic ectoparasitism in a Jurassic fly larva  

PubMed Central

The reconstruction of ancient insect ectoparasitism is challenging, mostly because of the extreme scarcity of fossils with obvious ectoparasitic features such as sucking-piercing mouthparts and specialized attachment organs. Here we describe a bizarre fly larva (Diptera), Qiyia jurassica gen. et sp. nov., from the Jurassic of China, that represents a stem group of the tabanomorph family Athericidae. Q. jurassica exhibits adaptations to an aquatic habitat. More importantly, it preserves an unusual combination of features including a thoracic sucker with six radial ridges, unique in insects, piercing-sucking mouthparts for fluid feeding, and crocheted ventral prolegs with upward directed bristles for anchoring and movement while submerged. We demonstrate that Q. jurassica was an aquatic ectoparasitic insect, probably feeding on the blood of salamanders. The finding reveals an extreme morphological specialization of fly larvae, and broadens our understanding of the diversity of ectoparasitism in Mesozoic insects. DOI: http://dx.doi.org/10.7554/eLife.02844.001

Chen, Jun; Wang, Bo; Engel, Michael S; Wappler, Torsten; Jarzembowski, Edmund A; Zhang, Haichun; Wang, Xiaoli; Zheng, Xiaoting; Rust, Jes

2014-01-01

393

A Jurassic eutherian mammal and divergence of marsupials and placentals.  

PubMed

Placentals are the most abundant mammals that have diversified into every niche for vertebrates and dominated the world's terrestrial biotas in the Cenozoic. A critical event in mammalian history is the divergence of eutherians, the clade inclusive of all living placentals, from the metatherian-marsupial clade. Here we report the discovery of a new eutherian of 160?Myr from the Jurassic of China, which extends the first appearance of the eutherian-placental clade by about 35?Myr from the previous record, reducing and resolving a discrepancy between the previous fossil record and the molecular estimate for the placental-marsupial divergence. This mammal has scansorial forelimb features, and provides the ancestral condition for dental and other anatomical features of eutherians. PMID:21866158

Luo, Zhe-Xi; Yuan, Chong-Xi; Meng, Qing-Jin; Ji, Qiang

2011-08-25

394

Triassic-Jurassic Mass Extinction: Evidence for Bolide Impact?  

NASA Astrophysics Data System (ADS)

The Triassic-Jurassic (TJ) mass extinction event is one of the most severe in geologic history and is one of the five largest in the Phanerozoic with as many as 80% of the species lost. It is also one of the most poorly understood. Only a few geologic sections have been identified for the TJ extinction and most of those are not well preserved. Previously, the paucity of suitable stratigraphic sections has prevented corroborative geochemical studies. Recently a well-preserved stratigraphic section spanning the Triassic-Jurassic boundary (˜200 mya) was identified at Kennecott Point, Queen Charlotte, Islands, British Columbia. Initial studies have shown that the Kennecott Point sequence is one of the best preserved and contains one of the most complete radiolarian microfossil turnovers known. Analyses of stable isotopes have shown that a 13C perturbation exits within the sequence and suggests a decline in organic productivity (Ward et al., 2001). Preliminary results of laser desorption mass spectrometry (LDMS) of selected Queen Charlotte samples suggest that fullerenes (C60 to C200) may be present in the Kennecott Point stratigraphic sequence. Previous studies have shown that fullerenes are present in the mass extinction boundary of the Permian-Triassic (˜251 mya) as well as the well-known "dinosaur" extinction event of the Cretaceous-Tertiary (˜65 mya). Therefore, three of the big five extinction events appear to have associated fullerenes. The possible presence of fullerenes along with the productivity collapse (rapid environmental change) suggests that a cometary or asteroidal impact may have occurred. Although no known impact crater exists, we hope to present chemical evidence that an impact or multiple impacts may have been responsible for the TJ mass extinction.

Perry, R.; Becker, L.; Haggart, J.; Poreda, R.

2003-04-01

395

Note on glauconitic sandstones in the Wairarapa, New Zealand  

Microsoft Academic Search

Cretaceous-Tertiary glauconitic sandstones near Flat Point, showing moderate to poor graded bedding, lamination, cross lamination, and flute marks, are tentatively considered to be turbidity-current deposits.These rocks contain an abundance of worm burrowings and tracks.

B. D. Webby; H. B. Van Den Heuvel

1965-01-01

396

National Occupational Health Survey of Mining. Sandstone (Dimension) Report.  

National Technical Information Service (NTIS)

The report prepared by the National Occupational Health Survey of Mining presents statistics concerning safety at three sites selected from the sandstone (dimension) population of active mining facilities in the United States. All of the sites were survey...

1990-01-01

397

Stress-Induced Anisotropic Poroelasticity Response in Sandstone.  

National Technical Information Service (NTIS)

We present measurements of the elastic and poroelastic (both drained and undrained) properties of intact Berea sandstone at confining pressures up to 50 MPa and differential stresses from 0 to 120 MPa. Tests were carried out under axisymmetric loading con...

D. A. Lockner N. M. Beeler

2003-01-01

398

Practical characterization of eolian reservoirs for development: Nugget Sandstone, Utah—Wyoming thrust belt  

NASA Astrophysics Data System (ADS)

The Jurassic eolian Nugget Sandstone of the Utah-Wyoming thrust belt is a texturally heterogeneous formation with anisotropic reservoir inherited primarily from the depositional environment. Original reservoir quality has been reduced somewhat by cementation and slightly enhanced by dissolution. Low-permeability, gouge-filled micro-faults compartmentalize the formation, whereas intermittently open fractures provide effective permeability paths locally. Where productive, the Nugget Sandstone ranges from approximately 800 to 1050 ft (244-320 m) thick at subsurface depths of 7500 to 15,000 ft (2286-4572 m). Porosity ranges from several percent to 25%, and permeability covers five orders of magnitude from hundredths of milliDarcies to Darcies. Some Nugget reservoirs are fully charged with hydrocarbons. Different stratification types have unique depositional textures, primary and diagenetic mineralogies, and deformational fabrics resulting in characteristic porosity, permeability, permeability directionality, and pore geometry attributes. Such characteristics can be determined from core analysis, mercury injection, nuclear magnetic resonance, conventional log, dipmeter and production data. Nugget dune deposits (good reservoir facies) primarily consist of grainflow and wind-ripple cross-strata, the former of which have the better reservoir quality and the lesser heterogeneity in bedding texture. High-permeability facies are commonly affected by local quartz and nodular carbonate cementation, chlorite (and lesser illite) precipitation, and minor framework and cement dissolution. Gouge-filled micro-faults are the predominant deformational overprint. Interdune, sand-sheet, and other water-associated deposits (poor reservoir facies) are characterized by low-angle wind-ripple laminae and more irregular bedding, some of which is associated with damp or wet conditions. Water-associated Nugget stratification generally contains the finest grained depositional textures and has the poorest reservoir properties. These non-dune facies contain intergranular micritic carbonate and illite precipitates and are most affected by compaction and pressure solution phenomena. Open types of fractures are somewhat more likely in this lower permeability rock. Depositional models incorporating dune morphologies, facies distribution, permeability directionality, and theoretical concepts regarding dune migration through time are useful in delineating correlative intervals most likely to have continuity and potential communication of reservoir properties. Stratigraphic models can be adapted for reservoir simulation studies and also can be utilized in solving structural resolution problems if correlatable vertical sequences and relatively consistent cross-strata orientations exist.

Lindquist, Sandra J.

1988-04-01

399

Results of a Survey of Residential Home Heating Fuel and Stove Type and Use in the Shiprock Area of the Navajo Nation  

USGS Publications Warehouse

For many Navajo people, coal provides an affordable and convenient means of home heating. However, coal combustion results in the formation and mobilization of materials that are known risk factors for respiratory and other diseases. The level of respiratory morbidity among the Navajo people is higher than can be explained by usual epidemiological risk factors. The Shiprock area of the Navajo Nation is somewhat unique in that atmospheric thermal inversions trap air pollution low to the ground, especially in winter. There are two large mine mouth coal-fired power plants located in the vicinity, with a third plant in the planning stages. Both of the existing power plants are exempt from regulation under the U.S. Environmental Protection Agency 1990 Amendments to the Clean Air Act due to their age. The purpose of this survey was to assess the fuel and stove type and use, and document other household characteristics that might be related to the exposure of potentially toxic coal combustion products. A total of 137 surveys was conducted in English and Navajo to ascertain and document fuel usage and the type, size and conditions of heating stoves used in both traditional and modern homes. Results have been presented to the community at the Shiprock Chapter in the Navajo language. To increase public awareness, ways to properly use and store coal and to improve stove function and ventilation were also shared.

Bunnell, Joseph E.; Garcia, Linda V.

2008-01-01

400

Hydromechanical properties of Fontainebleau sandstone: Experimental determination and micromechanical modeling  

Microsoft Academic Search

We measured ultrasonic velocity, hydraulic permeability, and specific storage capacity of eight blocks of Fontainebleau sandstone, a well-sorted, medium-grained, almost pure quartz-sandstone of Oligocene age, covering a range in connected porosity from 3% to 10% and varying significantly in pore geometry for a given porosity. Ultrasonic P-wave velocity measured on water-saturated samples covers the full range predicted by variational Hashin-Shtrikman

Insun Song; Jörg Renner

2008-01-01

401

Recognition of fifth-order cycles in a biodestratified shelf sandstone parasequence: Olmos sandstone, south Texas  

SciTech Connect

This investigation of the Olmos Sandstone (Upper Cretaceous), A.W.P. field, McMullen County, Texas, demonstrates the utility of using genetic units and sequence stratigraphy to discern the depositional architecture of these enigmatic sand bodies. The Olmos represents a single parasequence within a transgressive systems tract. The parasequence is dated as Maastrichtian UC 15, based on planktonic foraminifera. A transgressive surface marked by submarine erosion caps the Olmos. The overlying glauconitic shale and marl is a regional marker horizon recognizable on seismic profiles and wireline logs and represents the rapid vertical deepening of facies. The Olmos is interpreted as a low-relief sand shoal that accumulated on the middle to outer shelf under low-energy conditions and slow rates of deposition. Internally, the Olmos parasequence is comprised of eight subtle cleaning-upward genetic subunits 10-20 ft thick which formed in response to incremental shallowing/deepening events associated with fifth-order sea level cycles. These in turn constitute the overall shoaling upward Olmos parasequence. Each subunit is comprised of lithofacies A (a relatively clean biodestratified reservoir-quality sandstone with a trace fossil assemblage of robust U-shaped and vertical burrows), lithofacies B (a shaly, biodestratified nonreservoir sandstone and siltstone with small, predominantly horizontal burrows); or a stacked A/B sequence. Subunit contacts are gradational and burrowed; the upper contact is sharp and burrowed. The subunits correlate for 10 to 15 mi in both strike and dip directions except where shaled out or truncated by postdepositional erosion. These depositional concepts were used in conjunction with structure mapping and seismic inversion techniques to drill a successful outpost to A.W.P. field.

Conrad, K.T. (Mobil Erdgas-Erdoel, Celle (West Germany)); Snedden, J.W. (Mobil Exploration Norway, Inc., Stavanger (Norway)); Cooke, J.C. (Mobil Exploration and Production Services, Inc., Dallas, TX (USA))

1990-05-01

402

Attenuation of Landfill Leachate In Unsaturated Sandstone  

NASA Astrophysics Data System (ADS)

Landfill leachate emanating from old "dilute and disperse" sites represents a potential (and in many cases actual) threat to the integrity of groundwater. Indeed, this concern has been included in EU legislation (80/86/EEC), where key contaminants (e.g. ammonia, various toxic organic compounds and heavy metals) are explicitly highlighted in terms of their impact on groundwater. In the UK, whilst there are a substantial number of unlined landfills sited on major aquifers, many of these are in locations where there is a substantial unsaturated zone. Thus, there exists the opportunity for the modification and attenuation of contaminants prior to it encountering the water table. An understanding of likely changes in leachate content and concentrations at such sites will enable a more comprehensive assessment of the potential risks and liabilities posed by such sites to be evaluated. The Burntstump landfill, situated 8 km north of Nottingham (UK), is sited on an outcrop of Sherwood sandstone. The fine friable sand has been quarried since the 1960s and the excavated volume used to store municipal waste. Filling at the site commenced in the mid 1970s and originally was unlined. In 1978 the first of what was to become a series of boreholes was installed within an area of roughly 5 m radius over one of the original waste cells. Cores of the waste and underlying sandstone were extracted and analysed for a range of physical and chemical parameters. The most recent set of analyses were obtained in 2000. The series of investigations therefore provide an important record of leachate migration and modification through the unsaturated zone for over twenty years. The progression of the leachate front is clearly delineated by the chloride concentration profile with an average velocity of around 1.6 m.yr-1. Combining this value with an average (and reasonably uniform) measured moisture content of about 7% gives a mean inter-granular specific discharge of 110 mm.yr-1. An interesting feature of the sequences of porewater concentration profiles is the sharp leading front of the Cl plume. Thus indicating that very little solute dispersion appears to be occurring. This is probably to be due to the relatively uniform particle size of the sand matrix combined with the low moisture content, which has greatly constrained the available pore sizes in which flow occurs. A marked reduction in the mass of the chloride plume has been observed over the last 13 years. Analyses of core sample taken in 2000 show that the Cl profile has continued to lose mass and has now also separated into two peaks. The leading peak was located at a depth of 36 m below ground level (28 m below the base of the landfill) and in line with model predictions. The trailing peak was at a depth of 27 m bgl and was associated with a 0.3 m layer of marl and clay bands. Thus there is an indication that the changes in chloride mass are possibly due to the effects of heterogeneity, although other processes which could account for chloride removal from solution are also under consideration. The location of the TOC front up to 1992 was commensurate with that of Cl, indicating no effective retardation. This is consistent with the very low levels of organic carbon present in the sandstone. However, marked reductions in contaminant mass (substantially greater than those of Cl) have been observed. Analyses of volatile fatty acids has indicated a progressive breakdown of VFA components leading to simpler products so that by 1991 the dominant component was ethanoic acid (56% by mass). By 2000 the entire leading front of the TOC was absent. TOC was only found to be present at relatively low concentrations ( 100 mg.l-1) above the marl/clay band. Analyses of gas concentrations at the site have indicated that there has been a change in the redox potential in the volume of contaminated unsaturated sandstone below the waste cells during the last 10 years. With predominantly anaerobic conditions giving way to aerobic. This change appears to be related to the introduction of a landfill gas ex

Butler, A. P.; Brook, C.; Godley, A.; Lewin, K.; Young, C. P.

403

Water budget and mathematical model of the Coconino Aquifer, southern Navajo County, Arizona  

USGS Publications Warehouse

The main source of water in the 3,400-square-mile area of southern Navajo County, Ariz., is the large volume in storage in the Coconino aquifer. Withdrawals from the aquifer increased from about 13,800 acre-feet in 1960 to 38,400 acre-feet in 1972. Aquifer tests indicate that hydraulic conductivity ranges from 8 to 40 feet per day; the flow-net analysis indicates that the hydraulic conductivity may be as much as 80 feet per day in places. In the southern and central parts the aquifer is unconfined, and the storage coefficient is estimated to be about 0.15. In the northern and eastern parts the aquifer is confined, and the storage coefficient ranges from 0.00013 to 0.0014. A mathematical model was developed to simulate the groundwater system and to provide a management tool for estimating the effects of pumping. The model indicates that the inflow to and outflow from the aquifer were about 105,600 acre-feet in 1960 and that about 192,000 acre-feet of water was derived from storage in 1960-72. The model provides an approximation of the Coconino aquifer. (USGS)

Mann, Larry J.

1979-01-01

404

Heteromorphism and crystallization paths of katungites, Navajo volcanic field, Arizona, USA  

SciTech Connect

A swarm of thin, isochemical but heteromorphic dikes crops out in the valley of Hasbidito Creek in NE Arizona. The swarm is part of the dominantly potassic, mid-Tertiary Navajo volcanic field of the Colorado Plateau. Whole-rock chemical analyses of five samples from four of the dikes indicate that they are chemically identical to the katungites of Uganda. These dikes show the characteristic seriate-porphyritic texture of lamprophyres. Samples of an olivine-melilitite dike from the same swarm lack this texture and the chemical analysis, while similar to those of the other dikes, shows effects from the incorporation of xenocrystic olivine. Over 20 mineral phases have been identified in the Arizona samples and as many as 18 phases may occur in a single sample. The major phases are phlogopite, olivine, perovskite, opaque oxides, +- melilite and +- clinopyroxene. Based upon the modal mineralogies and textures of ten dike samples, we recognize five general non-equilibrium assemblages. Comparison of these assemblages with recent experimental results shows that they represent various combinations of complete and incomplete reactions. Reaction relations were determined by entering melt and phase compositions into the computer program GENMIX to obtain balanced reactions. By combining petrographic observations with mineral chemical data, balanced reactions from GENMIX, and the recently determined phase diagrams we are able to trace crystallization paths for the katungite magma.

Laughlin, A.W.; Charles, R.W.; Aldrich, M.J. Jr.

1986-01-01

405

Placebo studies and ritual theory: a comparative analysis of Navajo, acupuncture and biomedical healing  

PubMed Central

Using a comparative analysis of Navajo healing ceremonials, acupuncture and biomedical treatment, this essay examines placebo studies and ritual theory as mutually interpenetrating disciplines. Healing rituals create a receptive person susceptible to the influences of authoritative culturally sanctioned ‘powers’. The healer provides the sufferer with imaginative, emotional, sensory, moral and aesthetic input derived from the palpable symbols and procedures of the ritual process—in the process fusing the sufferer's idiosyncratic narrative unto a universal cultural mythos. Healing rituals involve a drama of evocation, enactment, embodiment and evaluation in a charged atmosphere of hope and uncertainty. Experimental research into placebo effects demonstrates that routine biomedical pharmacological and procedural interventions contain significant ritual dimensions. This research also suggests that ritual healing not only represents changes in affect, self-awareness and self-appraisal of behavioural capacities, but involves modulations of symptoms through neurobiological mechanisms. Recent scientific investigations into placebo acupuncture suggest several ways that observations from ritual studies can be verified experimentally. Placebo effects are often described as ‘non-specific’; the analysis presented here suggests that placebo effects are the ‘specific’ effects of healing rituals.

Kaptchuk, Ted J.

2011-01-01

406

Jurassic Cladocera (Crustacea, Branchiopoda) with a description of an extinct Mesozoic order  

Microsoft Academic Search

This paper describes extinct Jurassic Cladocera (Crustacea: Branchiopoda) from four well?known palaeontological sites. Leptodorosida zherikhini sp. nov., gen. nov. from Ust’?Baley (Lower Jurassic) belongs to an extinct family, Leptodorosididae fam. nov., and a new order, the Cryptopoda ordo nov. This order differs from the Haplopoda and the Onychopoda in having serially?similar filtering limbs with valves completely covering the post?cephalic body.

Alexey A. Kotov

2007-01-01

407

Late Triassic-Jurassic paleogeography and origin of Gulf of Mexico basin  

SciTech Connect

The basic structural and stratigraphic framework of the Gulf of Mexico Basin was established during the Late Triassic and the Jurassic. During the Late Triassic and Early Jurassic, as the North American plate started to separate from the South American and African plates, the area of the future basin was part of an extensive landmass broken by tensional grabens that were filled by red beds and volcanics. Marine deposition was restricted to embayments of the Pacific Ocean in northwestern and central Mexico. These marine embayments persisted during the early Middle Jurassic, but seawater did not reach the future Gulf of Mexico Basin until the Callovian. Widespread salt deposits known today from two separate areas of the basin resulted from this initial flooding. During the Late Jurassic, marine conditions progressively extended over increasingly larger parts of the Gulf of Mexico Basin. However, the basin was not connected to the Atlantic Ocean until late in the Jurassic. This paleogeographic reconstruction suggests that the Gulf of Mexico Basin formed as a result of the southward drift of the Yucatan continental block away from the remainder of the North American plate. The separation began in the Late Triassic, continued slowly and sporadically during the Early and Middle Jurassic, and quickened after the Middle Jurassic salt formed. As a result, the salt deposits were split into the two segments known today, and oceanic crust formed in the center of the basin. Early in the Late Jurassic, the Yucatan platform reached its present position and the Gulf of Mexico Basin was born. 14 figures.

Salvador, A.

1987-04-01

408

First Diagnostic Marine Reptile Remains from the Aalenian (Middle Jurassic): A New Ichthyosaur from Southwestern Germany  

PubMed Central

Background The Middle Jurassic was a critical time in the evolutionary history of ichthyosaurs. During this time interval, the diverse, well-studied faunas of the Lower Jurassic were entirely replaced by ophthalmosaurids, a new group that arose sometime prior to the Aalenian-Bajocian boundary and by the latest middle Jurassic comprised the only surviving group of ichthyosaurs. Thus, the Middle Jurassic Aalenian-Bathonian interval (176–165 million years ago) comprises the time frame during which ophthalmosaurids not only originated but also achieved taxonomic dominance. However, diagnostic ichthyosaur remains have been described previously from only a single locality from this interval, from the Bajocian of Argentina. Methodology/Principal Findings In this paper, we describe a new species of ichthyosaur based on a partial articulated specimen from the Middle Jurassic of southwestern Germany. This specimen was recovered from the Opalinuston Formation (early Aalenian) and is referable to Stenopterygius aaleniensis sp. nov. reflecting features of the skull and forefin. The genus Stenopterygius is diverse and abundant in the Lower Jurassic of Europe, but its presence has not previously been confirmed in younger (Middle Jurassic) rocks from the northern hemisphere. Conclusions/Significance This specimen represents the only diagnostic ichthyosaur remains reported from the Aalenian. It bears numerous similarities in size and in morphology to the Lower Jurassic species of the genus Stenopterygius and provides additional evidence that the major ecological changes hypothesized to have occurred at the end of the Toarcian took place sometime after this point and most likely did not occur suddenly. There is currently no evidence for the presence of ophthalmosaurids in the northern hemisphere during the Aalenian-Bathonian interval.

Maxwell, Erin E.; Fernandez, Marta S.; Schoch, Rainer R.

2012-01-01

409

The end-Triassic and Early Jurassic mass extinction records in the British Isles  

Microsoft Academic Search

WIGNALL, P.B. & BOND, D.P.G. 2008. The end-Triassic and Early Jurassic mass extinction records in the British Isles. Proceedings of the Geologists' Association, 119, 73-84. The complex crises of the end-Triassic and Early Jurassic (Toarcian) mass extinctions are well recorded in the British Isles where they coincide with major palaeoenvironmental changes. The end-Triassic extinction occurs within the quasi-marine Lilstock Formation,

Paul B. Wignall; David P. G. Bond

2008-01-01

410

Seismic stratigraphy and geologic history of Jurassic rocks, northeastern Gulf of Mexico  

Microsoft Academic Search

A grid of two-dimensional seismic data tied to exploration wells defines four Jurassic sequences in the northeastern Gulf of Mexico. These sequences correlate with well-known northern Gulf of Mexico basin stratigraphic units: the Louann Salt (L sequence), Norphlet and Smackover formations (N-S sequence), Haynesville Formation (H sequence), and Cotton Valley Group (C sequence). The Jurassic section overlies a basement surface

L. M. Dobson; R. T. Buffler

1997-01-01

411

Post-Jurassic tectonic evolution of Southeast Asia  

NASA Astrophysics Data System (ADS)

The accretionary growth of Asia, linked to long-term convergence between Eurasia, Gondwana-derived blocks and the Pacific, resulted in a mosaic of terranes for which conflicting tectonic interpretations exist. Here, we propose solutions to a number of controversies related to the evolution of Sundaland through a synthesis of published geological data and plate reconstructions that reconcile both geological and geophysical constraints with plate driving forces. We propose that West Sulawesi, East Java and easternmost Borneo rifted from northern Gondwana in the latest Jurassic, collided with an intra-oceanic arc at ~115 Ma and subsequently sutured to Sundaland by 80 Ma. Although recent models argue that the Southwest Borneo core accreted to Sundaland at this time, we use volcanic and biogeographic constraints to show that the core of Borneo was on the Asian margin since at least the mid Jurassic. This northward transfer of Gondwana-derived continental fragments required a convergent plate boundary in the easternmost Tethys that we propose gave rise to the Philippine Archipelago based on the formation of latest Jurassic-Early Cretaceous supra-subduction zone ophiolites on Halmahera, Obi Island and Luzon. The Late Cretaceous marks the shift from Andean-style subduction to back-arc opening on the east Asian margin. Arc volcanism along South China ceased by ~60 Ma due to the rollback of the Izanagi slab, leading to the oceanward migration of the volcanic arc and the opening of the Proto South China Sea (PSCS). We use the Apennines-Tyrrhenian system in the Mediterranean as an analogue to model this back-arc. Continued rollback detaches South Palawan, Mindoro and the Semitau continental blocks from the stable east Asian margin and transfers them onto Sundaland in the Eocene to produce the Sarawak Orogeny. The extrusion of Indochina and subduction polarity reversal along northern Borneo opens the South China Sea and transfers the Dangerous Grounds-Reed Bank southward to terminate PSCS south-dipping subduction and culminates in the Sarawak Orogeny on Borneo and ophiolite obduction on Palawan. We account for the regional plate reorganizations related to the initiation of Pacific subduction along the Izu-Bonin-Mariana Arc, the extrusion tectonics resulting from the India-Eurasia collision, and the shift from basin extension to inversion on Sundaland as an indicator of collision between the Australian continent and the active Asian margin. We generate continuously closing and evolving plate boundaries, seafloor age-grids and global plate velocity fields using the open-source and cross-platform GPlates plate reconstruction software. We link our plate motions to numerical mantle flow models in order to predict mantle structure at present-day that can be qualitatively compared to P- and S- wave seismic tomography models. This method allows us to analyse the evolution of the mantle related to Tethyan and Pacific subduction and to test alternative plate reconstructions. This iterative approach can be used to improve plate reconstructions in the absence of preserved seafloor and conjugate passive margins of continental blocks, which may have been destroyed or highly deformed by multiple episodes of accretion along the Asian margins.

Zahirovic, Sabin; Seton, Maria; Dietmar Müller, R.; Flament, Nicolas

2014-05-01

412

Chasing the Late Jurassic APW Monster Shift in Ontario Kimberlites  

NASA Astrophysics Data System (ADS)

A 30° gap was recognized in a composite APW path when global poles from predominantly igneous rocks were assembled in North American coordinates using plate reconstructions (Kent & Irving 2010 JGR). The 'monster shift' occurred between a 160-190 Ma cluster of mean poles at 75-80°N 90-110°E to a 140-145 Ma grouping centered at 60-65°N ~200°E. There are hardly any intermediate igneous poles whereas the rather divergent directions from the Late Jurassic Morrison Formation published by Steiner & Helsley (1975 GSA Bulletin) are subject to adjustments for Colorado Plateau rotation and sedimentary inclination error, neither of which are precisely known for this redbed unit sampled in Colorado. On the other hand, similar large rapid swings have been recognized in the Late Jurassic APW path for Adria (Channell et al. 2010 Paleo3), suggesting a global phenomena. In an effort to fill the data gap between ~145 and 160 Ma, we sampled accessible outcrops/subcrops of kimberlites in the Timiskaming area of Ontario, Canada, that are associated with high precision U-Pb perovskite ages (Heamon & Kjarsgaard 2000 EPSL). We report initial results from two of the intrusions: the 153.6±2.4 Ma Peddie kimberlite from outcrop and the Triple B kimberlite that was accessible by trenching and is assumed to be the same age as the nearby 153.7±1.8 Ma Seed kimberlite as delineated by aeromagnetic surveys and borings. Systematic progressive thermal demagnetization indicated in each unit a dominant characteristic component with unblocking temperatures to 575° that presumably reflect a magnetite carrier that will be checked by further rock magnetic experiments. Samples from the Peddie kimberlite had stable downward (normal polarity) magnetizations whose mean direction gives a paleopole at 73°N 184°E. In contrast, samples from the Triple B kimberlite have upward (reverse polarity) magnetizations with a well-grouped direction whose (north) paleopole is 78°N 197°E, proximal to the Peddie pole. The normal and reverse polarities suggest that sufficient time elapsed between emplacement of the Triple B and Peddie to give an opportunity to average secular variation. The combined ~154 Ma Triple B and Peddie pole encouragingly lies about halfway between igneous poles from North America nearest in age: the 169 Ma Moat volcanics and the 142 Ma Ithaca kimberlites. However, preliminary paleomagnetic results from some of the other sampled kimberlite bodies are more problematical and require further paleomagnetic and geochronological work.

Kent, D. V.; Muttoni, G.; Gee, J. S.; Kjarsgaard, B. A.

2012-12-01

413

Randomized, controlled trial efficacy of pneumococcal conjugate vaccine against otitis media among Navajo and White Mountain Apache infants.  

PubMed

We report the phase III trial efficacy of 7-valent pneumococcal conjugate vaccine against clinical and culture proven otitis media (OM) among Navajo and White Mountain Apache infants. Efficacy was -0.4% (95% CI: -19.4 to 15.6) for clinically-diagnosed OM, 5.1% (95% CI: -51.5 to 40.6) for severe OM, and 64% (95% CI: -34% to 90%) for vaccine serotype pneumococcal OM suggesting that this vaccine is efficacious for pneumococcal OM in this high risk population. PMID:18162944

O'Brien, Katherine L; David, Angeline B; Chandran, Aruna; Moulton, Lawrence H; Reid, Raymond; Weatherholtz, Robert; Santosham, Mathuram

2008-01-01

414

Constraints on the Jurassic time scale by /sup 40/Ar//sup 39/Ar dating of North Caucasian volcanic rocks  

SciTech Connect

/sup 40/Ar//sup 39/Ar age measurements on biotites and high-temperature plagioclases of Jurassic basaltic to rhyolitic subvolcanic rocks from the Northern Great Caucasus (USSR) yielded plateau and total argon ages between 190 and 180 Ma. The dated rocks are intrusive sills, dikes and laccoliths in sediments of the middle to upper Pliensbachian and of the lower Toarcian (Lower Jurassic). Pebbles of the volcanic rocks exist in the basal conglomerates of the Aalenian (base of the Middle Jurassic). Thus, their stratigraphic age is restricted to the Lower Jurassic stages of middle to upper Pliensbachian and Toarcian. Because of the scarcity of tie-points in the Lower Jurassic, the isotopic ages of these volcanic rocks, in spite of their rather large stratigraphic range, may serve as new calibration points for the improvement of the Jurassic time-scale.

Hess, J.C.; Lippolt, H.J.; Borsuk, A.M.

1987-07-01

415

Durabilité chimique de l'uraninite précipitée sur le grès du Navajo  

NASA Astrophysics Data System (ADS)

Batch and sand column experiments were conducted with sandstone and ground water to investigate the oxidation of uraninite. Uraninite and mackinawite precipitated by indigenous bacteria in contaminated ground water from a former uranium mill tailings site near Tuba City, Arizona, USA. Leaching of a sand column containing uraninite and mackinawite by oxygen-saturated uncontaminated ground water from the same site showed that uraninite was slowly dissolved. U(VI) concentration in the effluent of column did not exceed 4 ?g·L -1. Batch experiments showed that most of the oxygen was consumed by mackinawite oxidation. Hence it is concluded that the oxidation of uraninite is insignificant in the presence of mackinawite.

Abdelouas, Abdesselam; Lutze, Werner; Nuttall, Eric

1998-07-01

416

Transport of engineered silver (Ag) nanoparticles through partially fractured sandstones.  

PubMed

Transport behavior and fate of engineered silver nanoparticles (AgNP) in the subsurface is of major interest concerning soil and groundwater protection in order to avoid groundwater contamination of vital resources. Sandstone aquifers are important groundwater resources which are frequently used for public water supply in many regions of the world. The objective of this study is to get a better understanding of AgNP transport behavior in partially fractured sandstones. We executed AgNP transport studies on partially fissured sandstone drilling cores in laboratory experiments. The AgNP concentration and AgNP size in the effluent were analyzed using flow field-flow fractionation mainly. We employed inverse mathematical models on the measured AgNP breakthrough curves to identify and quantify relevant transport processes. Physicochemical filtration, time-dependent blocking due to filling of favorable attachment sites and colloid-facilitated transport were identified as the major processes for AgNP mobility. Physicochemical filtration was found to depend on solute chemistry, mineralogy, pore size distribution and probably on physical and chemical heterogeneity. Compared to AgNP transport in undisturbed sandstone matrix reported in the literature, their mobility in partially fissured sandstone is enhanced probably due to larger void spaces and higher hydraulic conductivity. PMID:24992708

Neukum, Christoph; Braun, Anika; Azzam, Rafig

2014-08-01

417

Fault-related Silurian Clinton sandstone deposition in Ohio  

SciTech Connect

Mapping the thickness of the Silurian Clinton sandstone reservoir and associated shale, sandstone, and carbonate facies in the subsurface of 40 counties in eastern Ohio reveals a general correspondence between major patterns of deposition and the location of faults that strike parallel with or subparallel to the depositional trends. Clinton delta-front sandstones, which occur along a line from Hocking and Perry Counties, through Knox, Holmes, and Wayne Counties northeast to Lake County, Ohio, parallel a line of major change in magnetic intensity in the basement, which is interpreted here to be the juncture between the more stable, less subsiding central Ohio carbonate bank and the more subsiding western edge of the Appalachian basin. The principal Clinton deltaic lobes occur in east-central and northeastern Ohio. The Clinton sandstone interval is thinner and starved of coarse clastic sediment close to the Rome trough, which is located along the southeasternmost Ohio border. Sediment distribution patterns indicate that deltaic deposits of Clinton sandstone were captured in the subsiding Rome trough at the border of southern Ohio during the Early Silurian. Farther north, deltaic sediments spread out across eastern Ohio to reach an elongate depocenter caused by minor subsidence at the central Ohio platform edge. There, deltaic sands intermittently filled the delta-edge trough, and spilled out as thin shelf sands onto the more stable platform, a site of predominantly mixed shale and carbonate deposition during the Early Silurian.

Coogan, A.H. (Kent State Univ., OH (USA))

1988-08-01

418

Microscopic scale characterization of ancient building sandstones from Saxony (Germany)  

SciTech Connect

Sandstone has been a traditional building material all over the world for centuries and is still used for this purpose today. Because of the various geological origin, sandstones may differ in petrography and mineralogy, which mainly determine their technical properties and weathering behavior. Therefore, a careful investigation of sandstone building materials is required and a complex analytical scheme was developed for this purpose. Sample material from important quarry regions of the Elbe Zone (Saxony, Germany) was investigated, which supplied material for a lot of famous buildings in the historic city center of Dresden, in Meissen and in the whole state of Saxony. The complex study included macroscopic rock description and detailed investigations by polarizing microscopy (phase composition, texture, grain size distribution), cathodoluminescence (CL) microscopy (quartz types, feldspar and kaolinite content), scanning electron microscopy (SEM; accessories, pore cement, diagenetic grain surface features), and pore-size distribution by Hg porosimetry. In a case study, mineralogical and technical properties of building sandstones from the Meissen cathedral (Saxony, Germany) were investigated and compared with material from potential historical source quarries. The results of the present study allowed to assign unequivocally historically used material to specific sandstone occurrences, and provide a comprehensive basis for the interpretation of weathering damage on the historical monuments. These data are useful for current conservation and reconstruction activities.

Goetze, Jens [Freiberg University of Mining and Technology, Department of Mineralogy, Brennhausgasse 14, D-09596 Freiberg (Germany)]. E-mail: goetze@mineral.tu-freiberg.de; Siedel, Heiner [Dresden University of Technology, Department of Geotechnical Engineering, Chair of Applied Geology, D-01062 Dresden (Germany)

2004-11-15

419

Tertiary age for upper Nubian sandstone formation, central Sudan  

SciTech Connect

In central and northern Sudan, oil exploration is now active in the basins containing sediments of the Nubian Sandstone Formation. On the evidence of planned pipeline construction, significant volumes of oil appear to have been discovered in southwestern Sudan. A newly discovered flora from the upper Nubian Sandstone Formation near Khartoum in central Sudan is Tertiary in age. The flora is well preserved, and comprises leaves, flowers, and fruits, many not yet described. At the generic level, they are comparable to forms that are known fro the Eocene to Miocene. Aquatic plants indicate a lacustrine paleoenvironment; humid tropical forests thrived on the lakeshores. The Nubian Sandstone Formation of Sudan had been considered to be entirely of Cretaceous age; this new flora shifts the upper boundary into the Tertiary. The Tertiary Hudi Chert, found in scattered outcrops in the region of Atbara, was considered to overlie the Nubian Sandstone Formation. The authors suggest that the Hudi Chert is partly age equivalent to the Tertiary upper Nubian Sandstone at Jebel Mudaha.

Prasad, G.; Lejal-Nicol, A.; Vaudois-Mieja, N.

1986-02-01

420

Paleogeographic and Tectonic Implications of Quartzose Sandstones of Barbados  

NASA Astrophysics Data System (ADS)

The provenance of Paleogene sandstones on the island of Barbados is relevant to various models of the tectonic evolution of the southern Caribbean area. Modal point counts of 26 sandstones from Barbados show that the constituent grains most likely were derived from a composite craton interior and orogenic margin. Abundant detrital polycrystalline quartz grains have affinities to a spectrum of low- to high-rank metamorphic/plutonic crystalline source rocks. Microprobe data suggest that feldspars were derived from metamorphic or plutonic source terrances. The complex heavy-mineral suite of the terrigenous sandstones, including glaucophane, chloritoid, titanite, zircon, and aluminosilicates, supports derivation from orogenic and cratonal terranes. Due to the complex history of the South American-Caribbean plate boundary and poor age constraints on timing of deposition, widely contrasting models have been proposed concerning the provenance of the sandstones. Convergence between the Aruba-Orchila arc and continental South America during the Paleogene resulted in the formation of an E-W trending foreland fold-thrust belt and foredeep. Dominant sediment dispersal was to the east-northeast along tectonic strike. The present study shows that the terrigenous sandstones on Barbados probably were deposited in deep-sea fans to the north of present-day Araya Peninsula during and shortly after the late middle Eocene. Probable source terranes include the Guayana Shield, the Caribbean Mountain System/interior foreland fold-thrust belt, and possibly (to a lesser extent) the Lesser Antilles magmatic arc or predecessor arc.

Kasper, D. C.; Larue, D. K.

1986-10-01

421

Boron-containing organic pigments from a Jurassic red alga  

PubMed Central

Organic biomolecules that have retained their basic chemical structures over geological periods (molecular fossils) occur in a wide range of geological samples and provide valuable paleobiological, paleoenvironmental, and geochemical information not attainable from other sources. In rare cases, such compounds are even preserved with their specific functional groups and still occur within the organisms that produced them, providing direct information on the biochemical inventory of extinct organisms and their possible evolutionary relationships. Here we report the discovery of an exceptional group of boron-containing compounds, the borolithochromes, causing the distinct pink coloration of well-preserved specimens of the Jurassic red alga Solenopora jurassica. The borolithochromes are characterized as complicated spiroborates (boric acid esters) with two phenolic moieties as boron ligands, representing a unique class of fossil organic pigments. The chiroptical properties of the pigments unequivocally demonstrate a biogenic origin, at least of their ligands. However, although the borolithochromes originated from a fossil red alga, no analogy with hitherto known present-day red algal pigments was found. The occurrence of the borolithochromes or their possible diagenetic products in the fossil record may provide additional information on the classification and phylogeny of fossil calcareous algae.

Wolkenstein, Klaus; Gross, Jurgen H.; Falk, Heinz

2010-01-01

422

Calcareous tempestites in pelagic facies (Jurassic, Betic Cordilleras, Southern Spain)  

NASA Astrophysics Data System (ADS)

Calcareous tempestite levels interbedded with Ammonitico Rosso and other related pelagic facies have been recognized. The previously described examples of calcareous tempestites in pelagic facies are scarce. The studied outcrops are Middle and Late Jurassic in age and correspond to ancient sediments in the Southern Iberian Continental Paleomargin. These outcrops are now included in a notably deformed geological unit (External Subbetic) in the External Zones of the Betic Cordillera. The calcareous tempestites are calcarenite and calcisiltite beds, grainstone and packstone with peloids and bioclasts (mainly 'filaments' and Saccocoma), showing an internal structure with hummocky cross-stratification. The deposits are thought to be formed by tropical storms and hurricanes and their recurrence intervals have been estimated (200 ka in average). The presence of these calcareous tempestite levels and the symmetrical wave-ripples on the top of the beds are two important arguments in favour of a palaeobathymetric interpretation of related pelagic sediments in the sense that the deposition occurred below, but near to the storm wave base, and that calcareous tempestites are episodic resedimentation, mainly coincident with relative sea-level falls (lowstand phases), in which major storm waves affect the sea bottom.

Molina, J. M.; Ruiz-Ortiz, P. A.; Vera, J. A.

1997-03-01

423

Examination of lower Jurassic mudrocks using backscattered electron microscopy  

SciTech Connect

The small size of many of the particles in mudrocks makes it almost impossible to image and identify them individually and in situ, using conventional light microscopy. Since the average mudrock contains about 60% clay minerals, an understanding of these minerals is central to the question of burial diagenesis and hydrocarbon generation. Much of the existing evidence concerning burial diagenesis relies on x-ray diffraction data (XRD), particularly with respect to the clay-sized (< 2 ..mu..m) fraction of mudrocks. Backscattered electron techniques (BSE) in scanning electron microscopy (SEM) together with energy-dispersive x-ray microanalysis (EDX), XRD, and electron microprobe analysis, indicate that Lower Jurassic mudrocks from the North Sea basin contain many clay mineral stacks up to 150 ..mu..m long. By studying polished mudrock sections with BSE and EDX, the sizes, shape, orientation, textural relations and internal compositional variation of the clay minerals can be observed in situ. Preliminary evidence suggests that the clay stacks are authigenic and may have formed at shallow burial depths during early diagenesis. In addition, sand- and silt-sized clay pellets (glauconite) composed chiefly of iron-bearing dioctahedral mica were observed in the sediment. The irregular shapes and textural intergrowths of many pellets suggest that active outward growth occurred, probably by a combination of displacement and replacement in the surrounding matrix material.

Krinsley, D.; Pye, K.

1984-07-01

424

Extreme adaptations for aquatic ectoparasitism in a Jurassic fly larva.  

PubMed

The reconstruction of ancient insect ectoparasitism is challenging, mostly because of the extreme scarcity of fossils with obvious ectoparasitic features such as sucking-piercing mouthparts and specialized attachment organs. Here we describe a bizarre fly larva (Diptera), Qiyia jurassica gen. et sp. nov., from the Jurassic of China, that represents a stem group of the tabanomorph family Athericidae. Q. jurassica exhibits adaptations to an aquatic habitat. More importantly, it preserves an unusual combination of features including a thoracic sucker with six radial ridges, unique in insects, piercing-sucking mouthparts for fluid feeding, and crocheted ventral prolegs with upward directed bristles for anchoring and movement while submerged. We demonstrate that Q. jurassica was an aquatic ectoparasitic insect, probably feeding on the blood of salamanders. The finding reveals an extreme morphological specialization of fly larvae, and broadens our understanding of the diversity of ectoparasitism in Mesozoic insects.DOI: http://dx.doi.org/10.7554/eLife.02844.001. PMID:24963142

Chen, Jun; Wang, Bo; Engel, Michael S; Wappler, Torsten; Jarzembowski, Edmund A; Zhang, Haichun; Wang, Xiaoli; Zheng, Xiaoting; Rust, Jes

2014-01-01

425

Neuroanatomy of the Marine Jurassic Turtle Plesiochelys etalloni (Testudinata, Plesiochelyidae)  

PubMed Central

Turtles are one of the least explored clades regarding endocranial anatomy with few available descriptions of the brain and inner ear of extant representatives. In addition, the paleoneurology of extinct turtles is poorly known and based on only a few natural cranial endocasts. The main goal of this study is to provide for the first time a detailed description of the neuroanatomy of an extinct turtle, the Late Jurassic Plesiochelysetalloni, including internal carotid circulation, cranial endocast and inner ear, based on the first digital 3D reconstruction using micro CT scans. The general shape of the cranial endocast of P. etalloni is tubular, with poorly marked cephalic and pontine flexures. Anteriorly, the olfactory bulbs are clearly differentiated suggesting larger bulbs than in any other described extinct or extant turtle, and indicating a higher capacity of olfaction in this taxon. The morphology of the inner ear of P. etalloni is comparable to that of extant turtles and resembles those of slow-moving terrestrial vertebrates, with markedly low, short and robust semicircular canals, and a reduced lagena. In P. etalloni the arterial pattern is similar to that found in extant cryptodires, where all the internal carotid branches are protected by bone. As the knowledge of paleoneurology in turtles is scarce and the application of modern techniques such as 3D reconstructions based on CT scans is almost unexplored in this clade, we hope this paper will trigger similar investigations of this type in other turtle taxa.

Carabajal, Ariana Paulina; Sterli, Juliana; Muller, Johannes; Hilger, Andre

2013-01-01

426

Jurassic mimicry between a hangingfly and a ginkgo from China  

PubMed Central

A near-perfect mimetic association between a mecopteran insect species and a ginkgoalean plant species from the late Middle Jurassic of northeastern China recently has been discovered. The association stems from a case of mixed identity between a particular plant and an insect in the laboratory and the field. This confusion is explained as a case of leaf mimesis, wherein the appearance of the multilobed leaf of Yimaia capituliformis (the ginkgoalean model) was accurately replicated by the wings and abdomen of the cimbrophlebiid Juracimbrophlebia ginkgofolia (the hangingfly mimic). Our results suggest that hangingflies developed leaf mimesis either as an antipredator avoidance device or possibly as a predatory strategy to provide an antiherbivore function for its plant hosts, thus gaining mutual benefit for both the hangingfly and the ginkgo species. This documentation of mimesis is a rare occasion whereby exquisitely preserved, co-occurring fossils occupy a narrow spatiotemporal window that reveal likely reciprocal mechanisms which plants and insects provide mutual defensive support during their preangiospermous evolutionary histories.

Wang, Yongjie; Labandeira, Conrad C.; Shih, Chungkun; Ding, Qiaoling; Wang, Chen; Zhao, Yunyun; Ren, Dong

2012-01-01

427

Ice age at the Middle-Late Jurassic transition?  

NASA Astrophysics Data System (ADS)

A detailed record of sea surface temperatures in the Northern Hemisphere based on migration of marine invertebrate fauna (ammonites) and isotopic thermometry (?18O values of shark tooth enamel) indicates a severe cooling at the Middle-Late Jurassic transition (MLJT), about 160 Ma ago. The magnitude of refrigeration (1-3°C for lower middle latitudes) and its coincidence in time with an abrupt global-scale fall of sea level documented through sequence stratigraphy are both suggestive of continental ice formation at this time. Ice sheets may have developed over the high-latitude mountainous regions of Far-East Russia. The drastic cooling just post-dated the Middle-Late Callovian widespread deposition of organic-rich marine sediments (e.g. northwestern Europe, Central Atlantic, and Arabian Peninsula). This thermal deterioration can thus be ascribed to a downdraw in atmospheric CO2 via enhanced organic carbon burial which acted as a negative feedback effect (i.e. the inverse greenhouse effect). The glacial episode of the MLJT climaxed in the Late Callovian, lasted about 2.6 Myr, and had a pronounced asymmetrical pattern composed of an abrupt (˜0.8 Myr) temperature fall opposed to a long-term (˜1.8 Myr), stepwise recovery. The glacial conditions at the MLJT reveal that atmospheric CO2 levels could have dropped temporarily to values lower than 500 ppmv during Mesozoic times.

Dromart, G.; Garcia, J.-P.; Picard, S.; Atrops, F.; Lécuyer, C.; Sheppard, S. M. F.

2003-08-01

428

Jurassic petroleum geology of southwestern Clarke County, Mississippi  

SciTech Connect

The Jurassic stratigraphy of southwestern Clark County, Mississippi, is representative of the central Gulf Coast. Evaporites, carbonates, and siliciclastics were deposited in restricted marine, shallow marine, transitional, and continental environments; structural development during and after deposition by regional faulting, local faulting, and salt movement directly affected hydrocarbon accumulation. Subsurface electric log data were studied from West Nancy, Nancy, East Nancy, Prairie Branch, and Lake Utopia fields and from the surrounding wildcats for the structural relations in and between producing fields and for the thickness and stratigraphic relations that affect production in three major units: the Norphlet and Smackover formations and the Buckner member of the Haynesville formation. Results suggest that (1) the East Nancy field probably has the best potential for future development because the original depositional feature is larger and older than that at the other fields and faulting has not greatly influenced entrapment or deposition, (2) the Smackover pay zone in the Prairie Branch field may be successfully developed on the south flank, and (3) the Nancy field might be developed on its southeast and northwest flanks in the upper oolite zone seen in the flank wells.

Jackson, J.B.; Harris, P.M.

1983-01-24

429

The timing of Jurassic orogenesis in the continental arc terrane of the western US Cordillera: Jackston Mountains, northwestern Nevada  

Microsoft Academic Search

Pre-Nevadan, Jurassic orogenesis appears to be characteristic of many Mesozoic arc assemblages of the western US Cordillera. In most places this deformation is Middle Jurassic ([approximately]170--160 Ma). The authors recent work in the Black Rock Desert (BRD) documents an episode of Early Jurassic metamorphism and tectonism in the Jackson Mountains (JM). Here, an extensive arc section, including the Norian to

M. J. Quinn; J. E. Wright

1993-01-01

430

Trace fossils from Jurassic lacustrine turbidites of the Anyao Formation (central China) and their environmental and evolutionary significance  

USGS Publications Warehouse

The Lower Jurassic Anyao Formation crops out near Jiyuan city, western Henan Province, central China. It is part of the infill of the nonmarine early Mesozoic Jiyuan-Yima Basin. In the Jiyuan section, this unit is about 100 m thick and consists of laterally persistent, thin and thick-bedded turbidite sandstones and mudstones displaying complete and base- or top-absent Bouma sequences, and thickbedded massive sandstones. The Anyao Formation records sedimentation within a lacustrine turbidite system developed in a pull-apart basin. Processes involved include high and low density turbidity currents, sometimes affected by liquefaction or fluidization. Facies analysis suggests that this succession is formed by stacked aggradational turbidite lobes. The absence of thick mudstone packages indicates that background sedimentation was subordinate to high frequency turbidite deposition. The Anyao Formation hosts a moderately diverse ichnofauna preserved as hypichnial casts on the soles of thin-bedded turbidite sandstones. The ichnofauna consists of Cochlichnus anguineus, Helminthoidichnites tenuis, Helminthopsis abeli, H. hieroglyphica, Monomorphichnus lineatus, Paracanthorhaphe togwunia, Tuberculichnus vagans, Vagorichnus anyao, tiny grazing trails, and irregularly branching burrows. Vagorichnus anyao occurs not only as a discrete trace, but also as a compound ichnotaxon intergrading with Gordia marina and Tuberculichnus vagans. Both predepositional and post-depositional traces are present on the soles of turbidites. This ichnofauna comprises both feeding and grazing traces produced by a deposit-feeding lacustrine benthic biota. Crawling traces are rare. Although certain ichnofossils (e.g. V. anyao, P. togwunia) show overall similarities with deep-sea agrichnia, they differ in reflecting remarkably less specialized feeding strategies, displaying overcrossing between specimens (and to a lesser extent, self-crossing), and in the case of V. anyao recording post-turbidite burrowing activity. The development of less specialized strategies than those displayed by deep-marine ichnofaunas may be related to less stable conditions, typical of lake settings. Oxygenation, energy, sedimentation rate (both event and background), food supply, soft-sediment deformation and erosion rate have mainly influenced trace-fossil distribution. Turbidity currents would have ensured oxygen (as well as food) supply to deep lake settings, thus allowing the establishment of a moderately diverse biota. Biogenic structures were mostly confined to the outer, low energy areas. High sedimentation rates and strong erosion precluded preservation of ichnofossils in inner lobe settings. The Anyao ichnofauna is of significance in furthering knowledge of the colonization of deep lakes throughout the stratigraphic record and in identification of additional nonmarine ichnofacies. The analyzed ichnofauna resembles late Paleozoic lacustrine assemblages described from different localities around the world and is regarded as a Mesozoic example of the Mermia ichnofacies. However, when compared with Paleozoic assemblages, the Anyao ichnofauna shows a clear dominance of burrows over surface trails, deeper burrowing penetration, larger size, and presence of relatively more complex structures. The high burrow/surface trail ratio may be indicative of lower preservation potential in the latter, thus reflecting a tap-honomic overprint. In contrast to the Paleozoic examples, the establishment of a relatively well-developed lacustrine infauna may have precluded preservation of surface trails. Burrower activity probably obliterated biogenic structures formed close to the sediment-water interface. ?? 1996 OPA (Overseas Publishers Association) Amsterdam B.V. Published in The Netherlands by Harwood Academic Publishers GmbH.

Buatois, L. A.; Mangano, M. G.; Wu, X.; Zhang, G.

1996-01-01

431

Late Jurassic (Kimmeridgian) larger benthic Foraminifera from Santiago Coatepec, SE Puebla, Mexico  

Microsoft Academic Search

A micropaleontologic study was carried out from samples collected along a section that crops out in the Santiago Coatepec Stream, located in the southeast of the state of Puebla, Mexico. The sedimentary sequence begins with a reddish conglomerate. Above, thick and thin layers of grey-greenish sandstones that continue in fine-grained, calcareous sandstones, and, finally, in limestones. The reddish conglomerate may

Lourdes Omaña; Celestina González Arreola

2008-01-01

432

Empirical prediction of porosity and permeability in sandstones  

SciTech Connect

Mean porosity and permeability of many sandstone intervals can be predicted prior to drilling. The predictive technique involves use of multivariate regression equations derived from calibration data sets. The effectiveness of this technique is illustrated by case studies, including several predrill porosity and permeability predictions. The critical independent variables controlling porosity (dependent variable) are detrital composition, sorting, time-integrated temperature history, and time-integrated pressure history. In sandstones with a high content of detrital quartz and chert, grain size may also affect porosity. Most important, the independent variables that correlate with porosity and permeability can be often estimated prior to drilling from facies models and seismic data. Accurate predictions are not limited to sandstones containing only primary porosity. The predictive applicability of the empirical approach is constrained by the limits imposed by the calibration data set.

Bloch, S. (Arco Oil and Gas Co., Plano, TX (United States))

1991-03-01

433

Optical coherence tomography for vulnerability assessment of sandstone.  

PubMed

Sandstone is an important cultural heritage material, in both architectural and natural settings, such as neolithic rock art panels. The majority of deterioration effects in porous materials such as sandstone are influenced by the presence and movement of water through the material. The presence of water within the porous network of a material results in changes in the optical coherence tomography signal intensity that can be used to monitor the wetting front of water penetration of dry porous materials at various depths. The technique is able to detect wetting front velocities from 1 cm s(-1) to 10(-6) cm s(-1), covering the full range of hydraulic conductivities likely to occur in natural sandstones from pervious to impervious. PMID:23669855

Bemand, Elizabeth; Liang, Haida

2013-05-10

434

Thermal maturity of Jurassic shales from the Newark Basin, U.S.A.: influence of hydrothermal fluids and implications to basin modeling  

USGS Publications Warehouse

Organic geochemical investigations were conducted on a series of cores that systematically sampled the uppermost Jurassic strata from the northern Newark Basin. Each sedimentary unit consists of fluvial red sandstones and siltstones with cyclic deposits of interbedded black lacustrine shales and gray deltaic siltstones. In a suite of organic-rich shales from the Boonton, Towaco