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1

Crouching theropod and Navahopus sauropodomorph tracks from the Early Jurassic Navajo Sandstone of USA  

E-print Network

Crouching theropod and Navahopus sauropodomorph tracks from the Early Jurassic Navajo Sandstone.G. 2008. Crouching theropod and Navahopus sauropodomorph tracks from the Early Jurassic Navajo Sandstone in the a cross-strata of the Lower Jurassic Navajo Sandstone of northern Arizona and southern Utah, USA. Tracks

Loope, David B.

2

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

E-print Network

Porosity and grain size controls on compaction band formation in Jurassic Navajo Sandstone Richard the porosity and average grain size of a sequence of stratigraphic layers of Navajo Sandstone are formed in layers having the largest average grain sizes (0.42­ 0.45 mm) and porosities (28

Fossen, Haakon

3

A REVIEW OF THE VERTEBRATE FAUNA OF THE LOWER JURASSIC NAVAJO SANDSTONE IN ARIZONA  

Microsoft Academic Search

The Lower Jurassic Navajo Sandstone of northern Arizona and southern Utah has yielded a diverse assemblage of late Early Jurassic terrestrial tetrapods from eolian and associated paleoenvironments. Although rare, vertebrate body fossils are represented by specimens of tritylodonts, crocodylomorphs, sauropodomorphs, and basal theropods (including Segisaurus halli). The vertebrate ichnofossil record is diverse and includes synapsids (Brasilichnium), crocodylomorphs (cf. Batrachopus), ornithischians

RANDALL B. IRMIS

2005-01-01

4

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. PMID:20352090

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

2010-01-01

5

Jurassic Navajo sandstone of Coyote Buttes, Utah/Arizona: coloration and diagenetic history, preservation of a dinosaur trample surface, and terrestrial analogs to Mars.  

E-print Network

??The Coyote Buttes, in Jurassic Navajo Sandstone, straddles the Utah-Arizona border at the northwest margin of Vermilion Cliffs National Monument. Its spectacular geology—cyclic eolian cross… (more)

Seiler, Winston Marmion

2008-01-01

6

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

7

Characterization of Navajo sandstone hydrous ferric oxide concretions.  

E-print Network

??In Utah's Grand Staircase Escalante National Monument (GSENM), abundant spheroidal hydrous ferric oxide (HFO) concretions (cemented mineral masses) of the Jurassic Navajo Sandstone are present… (more)

Potter, Sally Latham

2009-01-01

8

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

9

Downslope coarsening in aeolian grainflows of the Navajo Sandstone David B. Loope a,  

E-print Network

Downslope coarsening in aeolian grainflows of the Navajo Sandstone David B. Loope a, , James F: Grainflow Avalanche Aeolian Navajo Sandstone Dune Downslope coarsening in grainflows has been observed in ancient aeolian grainflows. We studied the grainflow stra- ta of the Jurassic Navajo Sandstone

Loope, David B.

10

Sandstone Formation on the Navajo Loop Trail  

USGS Multimedia Gallery

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

11

Morphologic Clues to the Origins of Iron OxideCemented Spheroids, Boxworks, and Pipelike Concretions, Navajo Sandstone of South-Central Utah, U.S.A.  

E-print Network

Concretions, Navajo Sandstone of South-Central Utah, U.S.A. Author(s): David B. Loope, Richard M. Kettler Sandstone of South-Central Utah, U.S.A. David B. Loope,1, * Richard M. Kettler,1 and Karrie A. Weber1,2 1 T Concretions cemented by iron oxide are abundant and diverse in the Jurassic Navajo Sandstone of southern Utah

Nebraska-Lincoln, University of

12

LANDFORMS GENERATED BY WIND EROSION OF NAVAJO SANDSTONE OUTCROPS AT THE WAVE (COLORADO PLATEAU, UTAH / ARIZONA BORDER)  

E-print Network

LANDFORMS GENERATED BY WIND EROSION OF NAVAJO SANDSTONE OUTCROPS AT THE WAVE (COLORADO PLATEAU on this wall. These features are similar in origin to the structures cut into Navajo Sandstone described photographers and hikers. The Navajo Sandstone has been eroded into four converging, erosional troughs

Nebraska-Lincoln, University of

13

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

USGS Publications Warehouse

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

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

2006-01-01

14

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

15

Synapsid Burrows in the Lower Jurassic Navajo Sandstone, Utah  

E-print Network

field work in Utah, and also provided his in-depth knowledge of ichnology and sedimentology, discussed potential ideas with me, as well as providing his editorial aid that greatly improved this thesis. My co-chair Larry D. Martin assisted me with his... in-depth knowledge of therapsids, early mammals, and mammal burrows, editorial aid that greatly improved this thesis as well as assistance in guiding me to new ideas. My committee member Robert Goldstein assisted me with petrographic analysis...

Riese, David

2011-05-03

16

Navajo Sandstone–brine–CO 2 interaction: implications for geological carbon sequestration  

Microsoft Academic Search

The injection of CO2 into deep saline aquifers is being considered as an option for greenhouse gas mitigation. However, the response of an aquifer\\u000a to the injected CO2 is largely unknown. Experiments involving the reaction of Navajo Sandstone with acidic brine were conducted at 200°C and\\u000a 25 or 30 MPa to evaluate the extent of fluid–rock interactions. The first experiment examined

Peng LuQi; Qi Fu; William E. Seyfried; Anne Hereford; Chen Zhu

2011-01-01

17

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

SciTech Connect

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

Schenk, C.J.; Peterson, F. (Geological Survey, Denver, CO (United States))

1991-06-01

18

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

19

Damage zone and slip-surface evolution over ?m to km scales in high-porosity Navajo sandstone, Utah  

Microsoft Academic Search

Detailed mapping of throw variations and deformation along twokm-scale normal faults in the high-porosity Navajo sandstone, Utah, has been used to investigate fault growth in this lithology. The faults consist of one or more through-going, striated, slip-surfaces, accommodating the greater part of the offset surrounded by a damage zone consisting of deformation band clusters and short, unconnected slip-surfaces. In contrast

Z. K. Shipton; P. A. Cowie

2001-01-01

20

NEW INFORMATION ON SEGISAURUS HALLI, A SMALL THEROPOD DINOSAUR FROM THE EARLY JURASSIC OF ARIZONA  

E-print Network

NEW INFORMATION ON SEGISAURUS HALLI, A SMALL THEROPOD DINOSAUR FROM THE EARLY JURASSIC OF ARIZONA, a small Early Jurassic dinosaur and the only theropod known from the Navajo Sandstone. Our study unknown in dinosaurs), seemingly solid centra and limb bones (atypical for theropods), and accessory

Hutchinson, John

21

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

SciTech Connect

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

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

1986-06-01

22

Frisco City sandstone: Upper Jurassic play in southern Alabama  

SciTech Connect

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

Montgomery, S.L. [Petroleum Consultant, Seattle, WA (United States); Baria, L.R. [Jura-Search, Inc., Jackson, MS (United States); Handford, C.R. [Bureau of Economic Geology, Austin, TX (United States)

1997-10-01

23

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

SciTech Connect

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

Harker, S.D. (Occidental Petroleum (Caledonia) Ltd., Aberdeen (United Kingdom)); Mantel, K.A. (Narwhal, London (United Kingdom)); Morton, D.J. (Deminex U.K. Oil and Gas Ltd., London (United Kingdom)); Riley, L.A. (Paleoservices, Watford (United Kingdom))

1991-03-01

24

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

25

Post-sedimentation transformations of Lower-Middle Jurassic sandstones of Great Caucases  

NASA Astrophysics Data System (ADS)

POST-SEDIMENTATION TRANSFORMATIONS OF LOWER-MIDDLE JURASSIC SANDSTONES OF GREAT CAUCASES M.I. Tuchkova Geological Institute Russian Academy of Sciences, Moscow, Russia tuchkova@geo.tv-sign.ru/ /Fax: (095) 2310443 Generalization of author’s and literature data is based on the analysis of sandstones cement and structure, composition and politypism of clay minerals and index of mica crystallinity. Fore zones of sandstone transformations are distinguished for Lower-Middle Jurassic sedimentary complexes of Great Caucases: 1) zone of neogenic chlorite and muscovite (index of crystallinity IC=1.0-2.0 mm) with wide development of epidote; solubility, blastic and spinulose structures, 2) zone of neogenic chlorite and sericite (IC=2.0-3.0 mm); solubility and spinulose structures, 3) zone of neogenic hydromica (IC=2.5-3.5 mm), kaolinite and/or montmorillonite minerals with microstylolite, conformal and conformal-regenerational contacts between grains, 4) zone of kaolinite and/or montmorillonite, mixed-layered and chlorite minerals with carbonate cement of pores filling, ferugination and conformal and microstylolite contacts between grains. Index of crystallinity of mica mineral IC=3.5-5.5 mm. In modern geological structure the region with most intensive transformations (zone 1) is traced in sandstones of here and there preserved Sinemurian-Lower Pliensbachian and Toarcian deposits in the belt of Jurassic deposits of the southern slope of Great Caucases. The extent of rock transformation increases northward and southward from the axial zone of Great Caucases. Represented zonality doesn’t depend on deposits thickness and doesn’t coincide with stratigraphycal borders. Post-sedimentation zonality of Jurassic deposits originated as a result of stress during the period of folding at the end of Middle and the beginning of Late Jurassic following the thrusting of northern flank of Great Caucases basin onto its axial part. The rocks of lowest part of Jurassic deposits of the southern slope, observed at the base of tectonically imbricated slices, were affected maximum transformations. They weren’t including in the subduction zone, but were only near this zone, so full sequence (up to metamorphism) of their transformations is not observed. The work was funded by RFBR, grant 02-05-64477.

Tuchkova, M. I.

2003-04-01

26

Navajo Peak  

USGS Multimedia Gallery

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

27

Navajo Dome  

USGS Multimedia Gallery

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

28

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

29

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

SciTech Connect

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

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

1986-05-01

30

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

USGS Publications Warehouse

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

Weiss, Emanuel

1987-01-01

31

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

Microsoft Academic Search

Detrital zircon grains (n=468) from eolian sandstones of Permian and Jurassic sand seas on the Colorado Plateau of southwest Laurentia fall into six separable age populations defined by discrete peaks on age–probability plots. The eolian sands include significant contributions from all Precambrian age belts of the Laurentian craton and all key plutonic assemblages of the Appalachian orogen marking the Laurentia–Gondwana

William R. Dickinson; George E. Gehrels

2003-01-01

32

Kinematic implications of joint zones and isolated joints in the Navajo Sandstone at Zion National Park, Utah: Evidence for Cordilleran relaxation  

NASA Astrophysics Data System (ADS)

At Zion National Park (ZNP) the landscape is a consequence of differential weathering of the Navajo Sandstone where closely spaced vertical joints constitute joint zones that erode to form regularly spaced (half kilometer) slot canyons striking 351°. Between these joint zones is a set of isolated joints striking 339°. Fracture interaction and horsetail/wing crack development indicate that the 339° striking joint set is younger than the 351° striking joint zones, despite the lateral extent of stress reduction shadows in the vicinity of the large-scale joint zones. In addition to an older, less pervasive, ˜020° joint set, this sequence of jointing records a counterclockwise rotation of the regional extension directed from WNW to WSW in the Navajo Sandstone at ZNP. ZNP is located at the western margin of the Colorado Plateau, ˜100 km east of the major normal faults of the northeastern central Basin and Range subprovince. Extension within the eastern central Basin and Range initiated during the Miocene and exhibited a WSW extension direction [, 1971; , 1988; , 2000]. The correlation between nearby Basin and Range extension and the extension direction for the 351° tending joint zones of ZNP is so close that the jointing at ZNP is interpreted as evidence for modest, yet pervasive Basin and Range extension in the western margin of the Colorado Plateau.

Rogers, Christie M.; Myers, Douglas A.; Engelder, Terry

2004-02-01

33

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

34

Sandstone Texture  

USGS Multimedia Gallery

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

35

Bryce Canyon's Navajo Loop Trail  

USGS Multimedia Gallery

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

36

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

NASA Astrophysics Data System (ADS)

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

Dickinson, William R.; Gehrels, George E.

2003-12-01

37

Environment of deposition of the upper Jurassic "Gray" sandstones, Terryville field, Lincoln Parish, Louisiana  

E-print Network

which decreases permeability and subsequent flow of subsurface waters which deposited the cements. Compositionally, no variations in cement occurs vertically in bedsets of either reservoir facies. Megascopic fragments in the sandstones include shale...

Mani, Philip Charles

2012-06-07

38

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

USGS Publications Warehouse

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

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

2013-01-01

39

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

40

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

41

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

42

Environment of deposition and reservoir facies of the Taylor "B" Sandstone, Cotton Valley group (Upper Jurassic), Kildare Field, Cass County, Texas  

E-print Network

ENVIRONMENT OF DEPOSITION AND RESERVOIR FACIES OF THE TAYLOR "8" SANDSTONE, COTTON VALLEY GROUP (UPPER JURASSIC), KILDARE FIELD, CASS COUNTY, TEXAS A Thesis by CYNTHIA ENGLAND SLACK Submitted to the Graduate College of Texas AIIM University... COUNTY, TEXAS A Thesis by -CYNTHIA ENGLAND BLACK Approved as to styIe and content by: o ert R. Berg (Chairman of Committ e) omas I. ie (I'iember) urray Hi&nord (tiemb r ) bee . Stan'ton ( ead of Department) Nay 1983 ABSTRACT Environment...

Black, Cynthia England

1983-01-01

43

Snow on the Navajo Loop Trail  

USGS Multimedia Gallery

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

44

Cedars on the Navajo Loop Trail  

USGS Multimedia Gallery

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

45

Hoodoo on the Navajo Loop Trail  

USGS Multimedia Gallery

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

46

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

SciTech Connect

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

Jones, L.S.; Blakey, R.C. (Univ. of Northern Arizona, Flagstaff, AZ (United States). Dept. of Geology)

1993-09-01

47

Disseminated `jigsaw piece' dolomite in Upper Jurassic shelf sandstones, Central North Sea: an example of cement growth  

E-print Network

: an example of cement growth during bioturbation? JAMES P. HENDRY*1 , MARK WILKINSON , ANTHONY E. FALLICKà crystals and consequent cementation of the grain framework. Continued exchange of Mg2+ and Ca2 on calcite cementation in marine sandstones in recent years has greatly improved our understanding

Haszeldine, Stuart

48

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

49

Geology Fieldnotes: Navajo National Monument, Arizona  

NSDL National Science Digital Library

Navajo National Monument is located on the Colorado Plateau in Arizona. Information on this site focuses on the Native American history of the area, including details about Keet Seel, an Anasazi village built in a sandstone cliff alcove. Other resources include visitor information, maps, and links to additional facts.

50

Triassic and Jurassic rocks at Currie, Nevada Preliminary paleontologic evidence  

SciTech Connect

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

Johnson, E.A.; Dubiel, R.F.; Brouwers, E.M. (Geological Survey, Denver, CO (United States)); Litwin, R.J. (Geological Survey, Reston, VA (United States)); Ash, S.R. (Weber State Coll., Ogden, UT (United States)); Good, S.C. (State Univ. Coll., Cortland, NY (United States))

1993-04-01

51

Two Bridges Formation on the Navajo Loop Trail  

USGS Multimedia Gallery

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

52

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

53

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

54

Rock doughnut and pothole structures of the Clarens Fm. Sandstone in the Karoo Basin, South Africa: Possible links to Lower Jurassic fluid seepage  

E-print Network

Rock doughnut and pothole structures of the Clarens Fm. Sandstone in the Karoo Basin, South Africa Morphology Process origins Clarens Fm. Sandstone South Africa has a wealth of sandstone landforms, yet many potholes (mean=37.8; n=150) and surrounding sandstone platform (mean=39.7; n=250). The petrography

Svensen, Henrik

55

Annual monsoon rains recorded by Jurassic dunes.  

PubMed

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

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

2001-07-01

56

The Navajo Yearbook.  

ERIC Educational Resources Information Center

The Navajo Yearbook began as an annual report to relate progress in carrying out provisions of the Navajo-Hopi Long Range Rehabilitation Act (P.L. 474 - 81st Congress), but the scope has been expanded to include all programs conducted on the reservation. This volume, the eighth in the series, is designed to reflect changing problems, changing…

Young, Robert W., Comp.

57

Conference on Navajo Orthography.  

ERIC Educational Resources Information Center

This report on the Conference on Navajo Orthography, held in Albuquerque, New Mexico on May 2-3, 1969 constitutes a summary of the discussion and decisions of a meeting which was convened by the Center for Applied Linguistics under contract with the Bureau of Indian Affairs to agree on an orthography for the Navajo language. The immediate purpose…

Ohannessian, Sirarpi; And Others

58

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

59

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

ERIC Educational Resources Information Center

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

Norton, Katie Jebb

60

NAVAJO ELECTRIFICATION DEMONSTRATION PROJECT  

SciTech Connect

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

Terry W. Battiest

2008-06-11

61

Auxiliary Information for "Wind-blown sandstones cemented by sulfate and clay minerals in Gale  

E-print Network

Auxiliary Information for "Wind-blown sandstones cemented by sulfate and clay minerals in Gale. Sharp exhibit features consistent with eolian sandstones that may be cemented by sulfates. As described to features observed in terrestrial eolian sandstones such as the Navajo sandstone in the southwestern U

62

Architectural studies of Jurassic-Cretaceous fluvial units, Colorado Plateau  

SciTech Connect

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

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

1989-03-01

63

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.

64

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.

WGBH Educational Foundation

2012-03-23

65

Social Services: The Navajo Way.  

ERIC Educational Resources Information Center

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

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

2002-01-01

66

Discriminant Analysis of XRF Data from Sandstones of Like Facies and Appearance: A Method for Identifying a Regional Unconformity, Paleotopography,  

E-print Network

Discriminant Analysis of XRF Data from Sandstones of Like Facies and Appearance: A Method Reserved #12;ABSTRACT Discriminant Analysis of XRF Data from Sandstones of Like Facies and Appearance Sandstone, Navajo Sandstone, discriminant analysis, XRF, J-1 unconformity, elemental composition, surface

Seamons, Kent E.

67

A conceptual model for the origin of fault damage zone structures in high-porosity sandstone  

E-print Network

A conceptual model for the origin of fault damage zone structures in high-porosity sandstone Zoe K-porosity sandstones. Damage zone deformation has been particularly well constrained for two 4-km-long normal faults formed in the Navajo Sandstone of central Utah, USA. For these faults the width of the damage zone

Cowie, Patience

68

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

69

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.

70

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.

71

A History of Navajo Clans. First Edition.  

ERIC Educational Resources Information Center

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

Lynch, Regina H.; And Others

72

To Be A Navajo. Second Edition, 1976.  

ERIC Educational Resources Information Center

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

Begay, Shirley M., Ed.

73

Characterization of Roabiba Sandstones Reservoir in Bintuni Field, Papua, Indonesia  

E-print Network

Bintuni Field has two Middle Jurassic gas reservoirs, Upper and Lower Roabiba Sandstone reservoirs, with the estimated reserve from eight appraisal drilled wells of 6.08 tcf. The field has not been producing commercially. The main gas reservoir...

Vera, Riene

2011-02-22

74

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

75

Small faults formed as deformation bands in sandstone  

Microsoft Academic Search

Small faults with displacements of a few millimeters or centimeters are abundant in the Entrada and Navajo Sandstones, in the San Rafael Desert, Utah, where they are important primary structures, preceding the development of large faults with displacements of several meters or tens of meters. The small faults contain no surfaces of discontinuity, rather they occur asdeformation bands about one

Atilla Aydin

1978-01-01

76

Navajo Students and "Postcolonial" Literature.  

ERIC Educational Resources Information Center

Shares how a 12-week course for second-semester seniors called "Cultures in Conflict: Post-Colonial Literature from Africa, the Caribbean, and the Pacific" offers students on a Navajo reservation important insights into how other peoples have dealt with racial misunderstandings, inequities of power, and shifts in traditional values and beliefs.…

Lucas, Kurt

1990-01-01

77

Traditional Navajo Maps and Wayfinding  

ERIC Educational Resources Information Center

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

Francis, Harris; Kelley, Klara

2005-01-01

78

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

79

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.

World Information Service on Energy Uranium Project

80

Facies Analysis and Reservoir Characterization of Subtidal, Intertidal, and Supratidal Zones of the Mudstone-rich Entrada Sandstone, South-Central Utah.  

E-print Network

??Understanding thickness variation and facies transitions in the mudstone-rich part of the Upper Middle Jurassic (Callovian) Entrada Sandstone depositional system is critical for constraining the… (more)

Hicks, Tanner Charles

2011-01-01

81

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

E-print Network

Mineral paragenesis and textures associated with sandstone-hosted roll-front uranium deposits, NW, Wuyiyi and Shihongtan sandstone-hosted roll-front uranium deposits, northwest China. The mineralization is hosted by Lower­Middle Jurassic coarse- to medium-grained sandstones, which are dark-gray to black due

Fayek, Mostafa

82

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.

83

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.

Margaret Mayer

84

"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.

85

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.

86

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

87

Provenance of Norphlet sandstone, northern Gulf Coast  

SciTech Connect

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

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

1987-09-01

88

Navajo Leadership and Government: A History. Sixth-Ninth Grade Navajo Bilingual-Bicultural Social Studies Curriculum.  

ERIC Educational Resources Information Center

This history of Navajo leadership and government, part of the sixth-ninth grade Navajo bilingual-bicultural social studies curriculum from the Navajo Curriculum Centers, covers types of government from the animal leaders of Navajo legend to modern times. The text is divided into five chapters: "The First Leaders,""New Neighbors--New…

McCarty, T. L.; Wallace, Stephen

89

Sandstone Quarry  

USGS Multimedia Gallery

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

90

Diné (Navajo) Ethno- and Archaeoastronomy  

NASA Astrophysics Data System (ADS)

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

Chamberlain, Von Del

91

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

SciTech Connect

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

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

1986-05-01

92

Development of faults as zones of deformation bands and as slip surfaces in sandstone  

Microsoft Academic Search

Three forms of fault are recognized in Entrada and Navajo Sandstones in the San Rafael Desert, southeastern Utah; deformation bands, zones of deformation bands, and slip surfaces. Small faults occur asdeformation bands, about one millimeter thick, in which pores collapse and sand grains fracture, and along which there are shear displacements on the order of a few millimeters or centimeters.

Atilla Aydin; Arvid M. Johnson

1978-01-01

93

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

94

Serum cholesterol concentrations among Navajo Indians.  

PubMed Central

Navajo Indians have been reported by earlier investigators to have low concentrations of serum lipids and a low prevalence of hyperlipidemia, as well as low rates of ischemic heart disease. However, no data on serum lipid concentrations among Navajos have been reported for more than two decades. The authors conducted a study to determine the distribution of concentrations of serum total cholesterol (TC), high density lipoprotein cholesterol, low density lipoprotein cholesterol, and triglyceride among persons 25-74 years old living in a representative community on the Navajo Indian reservation. Data are reported for 255 subjects, 105 men and 150 women, ages 25-74 years. The authors compared these data to those for the general population as determined by the second National Health and Nutrition Examination Survey (NHANES II). TC concentrations among Navajo men were similar to those from NHANES II. TC concentrations among younger Navajo women were similar to those for women younger than 55 years from NHANES II, but were significantly lower among older Navajo women. While 27.6 percent of men ages 25-74 years studied in NHANES II had TC concentrations greater than 240 milligrams per deciliter, 33.8 percent of Navajo men had similarly elevated TC. However, the prevalence of serum TC concentrations greater than 240 milligrams per deciliter among Navajo women (17.5 percent) was about half that among women studied in NHANES II (32.9 percent). A similar pattern was found for low density lipoprotein cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1738814

Sugarman, J R; Gilbert, T J; Percy, C A; Peter, D G

1992-01-01

95

Sandstone Cliffs  

USGS Multimedia Gallery

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

96

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

97

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.

Chris Shuey

98

Journal of the Geological Society, London, Vol. 162, 2005, pp. 939949. Printed in Great Britain. Evolution of damage zone geometry and intensity in porous sandstone  

E-print Network

. 939 Evolution of damage zone geometry and intensity in porous sandstone: insight gained from strain materials such as sandstone or limestone, fault-related damage zones form arrays of deformation bands, which-related damage zones within the brittly deformed Jurassic Wingate Sandstone exposed in the Laramide

99

Navajo Adult Basic Education: Final Report 1971-1972.  

ERIC Educational Resources Information Center

The thrust of the Navajo Adult Basic Education (NABE) program is aimed at three major objectives. First, it seeks to establish, through the study of history and current events, a feeling of pride in Navajo cultural heritage, promoting self-esteem and building self-confidence. Next, it prepares the Navajo to function better in those areas of the…

Navajo Community Coll., Tsaile, AZ.

100

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

101

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

102

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

ERIC Educational Resources Information Center

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

Robbins, Lynn A.

103

Jurassic Reef Park  

NSDL National Science Digital Library

This is a bilingual, educational website from Munich, Germany. The main feature is a virtual field trip to the reefs of the Jurassic period. Besides a view of the Jurassic reefs, their builders, and their ecological settings, there is also an emphasis on the importance of modern reefs as indicators of the state-of-health of the globe and evidence of how some changes in the composition of reefs may represent the forerunners of catastrophic, regional or global, environmental change.

Reinhold Leinfelder

104

Determinants of Blood Pressure in Navajo Adolescents.  

ERIC Educational Resources Information Center

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

Coulehan, John L.; And Others

1990-01-01

105

Kemik sandstone: inner shelf sand from northeast Alaska  

SciTech Connect

The upper Neocomian Kemik Sandstone crops out in and around Ignek Valley in northeast Alaska. It lies unconformably on the Jurassic to Lower Cretaceous Kingak Shale, and is overlain by the Hauterivian to Barremian Pebble shale. It is a fine-grained, glauconitic quartzose sandstone, up to 120 ft thick. Four lithofacies are recognized: (1) a basal, moderately well-sorted pebble conglomerate; (2) fine to very fine-grained, laminated and bioturbated sandstones; (3) a poorly sorted conglomerate; and (4) low-angle to hummocky cross-stratified fine-grained sandstones. Facies relationships suggest that the basal conglomerate represents a transgressive lag deposit. It is overlain by a sequence comprising laminated and bioturbated sandstones with interbedded, poorly sorted conglomerates. The sandstones exhibit a mixed assemblage of ichnofossils, including Gyrochorte, Muensteria, Ophiomorpha, Planolites, and Skolithos, and (.)Conichnus. In places, they grade upward from low-angle laminations to symmetrical ripple forms to silty laminated deposits. Their upper parts are bioturbated, but to varying extent. these sandstones and the conglomerates were deposited abruptly but sporadically below storm wave base by storm-generated currents. The sandstones were subsequently modified by strong but waning oscillating storm waves. The hummocky cross-stratified sediment comprises an upper sequence that was probably deposited under the influence of storm-induced conditions between fair-weather and storm wave base. The Kemik Sandstone represents a storm-deposited inner shelf sand with regressive characteristics, deposited within an overall transgressive setting.

Melvin, J.

1986-05-01

106

Sedimentology and sequence stratigraphy of the Bryne and Lulu Formations, Middle Jurassic, northern Danish Central Graben  

Microsoft Academic Search

The Middle Jurassic Bryne and Lulu Formations of the Søgne Basin (northern part of the Danish Central Graben) consist of fluvially-dominated coastal plain deposits, overlain by interfingering shoreface and back-barrier deposits. Laterally continuous, mainly fining-upwards fluvial channel sandstones that locally show evidence for tidal influence dominate the alluvial\\/coastal plain deposits of the lower Bryne Formation. The sandstones are separated by

Jan Andsbjerg

2003-01-01

107

Dinosaurs as Possible Avulsion Enablers in the Upper Jurassic Morrison Formation, East-Central Utah  

Microsoft Academic Search

The Upper Jurassic Salt Wash Member of the Morrison Formation in east-central Utah contains low sinuosity, ribbon-shaped fluvial channel sandstones enclosed by variegated mudstones. Channel sandstones formed when avulsion (the relatively abrupt shift of a river to a new channel) relocated a channel, after which extensive in-channel and minor near-channel sand deposition occurred. Interpretation of sedimentological, paleontological, and paleoclimatic data,

Lawrence S. Jones; Edmund R. Gustason

2006-01-01

108

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

Code of Federal Regulations, 2011 CFR

...false Approval of the Navajo Nation's abandoned mine land plan. 756.13 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.13 Approval of the Navajo Nation's abandoned mine land plan. The Navajo...

2011-07-01

109

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

Code of Federal Regulations, 2013 CFR

...false Approval of the Navajo Nation's abandoned mine land plan. 756.13 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.13 Approval of the Navajo Nation's abandoned mine land plan. The Navajo...

2013-07-01

110

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

...false Approval of the Navajo Nation's abandoned mine land plan. 756.13 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.13 Approval of the Navajo Nation's abandoned mine land plan. The Navajo...

2014-07-01

111

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

Code of Federal Regulations, 2012 CFR

...false Approval of the Navajo Nation's abandoned mine land plan. 756.13 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.13 Approval of the Navajo Nation's abandoned mine land plan. The Navajo...

2012-07-01

112

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

Code of Federal Regulations, 2010 CFR

... (a) The Navajo Nation, Navajo Abandoned Mine Land Reclamation Department, Division of Natural Resources, Navajo Nation Inn—Office Complex, P.O. Box 1875, Window Rock, AZ 86515, Telephone: (520) 871-7593. (b) Office of...

2010-07-01

113

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

114

"Dine Bikeya": Teaching about Navajo Citizenship and Sovereignty  

ERIC Educational Resources Information Center

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

Washington, Elizabeth Yeager; van Hover, Stephanie

2011-01-01

115

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

116

Navajo Area Health and Physical Education Curriculum Guidelines.  

ERIC Educational Resources Information Center

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

Tomah, Kent; And Others

117

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

ERIC Educational Resources Information Center

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

Two Bears, Davina R.

2006-01-01

118

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

119

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

120

Navajo Uranium Education Programs: The Search for Environmental Justice  

ERIC Educational Resources Information Center

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

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

2004-01-01

121

Revisiting the Navajo way: lessons for contemporary healing.  

PubMed

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

Schneider, Gregory W; DeHaven, Mark J

2003-01-01

122

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

NASA Astrophysics Data System (ADS)

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

Cherdantseva, D.; Krasnoshchekova, L.

2014-08-01

123

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

124

Pennsylvanian to Jurassic eolian transportation systems in the western United States  

USGS Publications Warehouse

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

Peterson, F.

1988-01-01

125

Navajo coal and air quality in Shiprock, New Mexico  

USGS Publications Warehouse

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

Bunnell, Joseph E.; Garcia, Linda V.

2006-01-01

126

Geometric analysis and scaling relations of deformation bands in porous sandstone  

Microsoft Academic Search

Displacement, length and linkage of deformation bands have been studied in Jurassic sandstones in southeastern Utah. Isolated deformation bands with lengths (L) that span more than three orders of magnitude show similar displacement (D) profiles with more or less centrally located maxima and gently increasing gradient toward the tips. Soft- and hard-linked examples exhibit steeper displacement gradients near overlap zones

Haakon Fossen; Jonny Hesthammer

1997-01-01

127

Navajo coal and air quality in Shiprock, New Mexico  

USGS Publications Warehouse

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

Bunnell, Joseph E.; Garcia, Linda V.

2006-01-01

128

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 ...

129

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

130

Assistive Technology Provision Within the Navajo Nation  

PubMed Central

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

Ripat, Jacquie D.

2014-01-01

131

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

SciTech Connect

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

Eschner, T.B.; Kocurek, G.

1988-08-01

132

Jurassic Polar Movement Relative to North America  

Microsoft Academic Search

Previous palcomagnetic studies of Jurassic rocks have not given concordant results and have led to the conclusion that the Jurassic pole position was possibly close to the present geographic pole. To test that supposition, the Kayenta, Carmel, Entrada, and Summerville formations were sampled from the extensive Jurassic sedimentary sequence in eastern Utah. The Lower and Upper Jurassic Kayenta and Summerville

ANY C. E. HELSLEY

1972-01-01

133

Bryce Canyon Sandstone  

USGS Multimedia Gallery

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

134

Snow-covered Sandstone  

USGS Multimedia Gallery

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

135

Capitol Reef Sandstone Cliff  

USGS Multimedia Gallery

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

136

Capitol Reef Sandstone Monolith  

USGS Multimedia Gallery

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

137

Middle Jurassic sand reservoirs of Tazovskoe field (West Siberia)  

NASA Astrophysics Data System (ADS)

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

Kurasov, I. A.

2012-12-01

138

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

Code of Federal Regulations, 2012 CFR

...Required amendments to the Navajo Nation's abandoned mine land plan. 756.15 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756...Required amendments to the Navajo Nation's abandoned mine land plan. Pursuant...

2012-07-01

139

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

Code of Federal Regulations, 2010 CFR

...Required amendments to the Navajo Nation's abandoned mine land plan. 756.15 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756...Required amendments to the Navajo Nation's abandoned mine land plan. Pursuant...

2010-07-01

140

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

...of amendments to the Navajo Nation's abandoned mine land plan. 756.14 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756...of amendments to the Navajo Nation's abandoned mine land plan. (a)...

2014-07-01

141

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

Code of Federal Regulations, 2013 CFR

...Required amendments to the Navajo Nation's abandoned mine land plan. 756.15 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756...Required amendments to the Navajo Nation's abandoned mine land plan. Pursuant...

2013-07-01

142

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

...Required amendments to the Navajo Nation's abandoned mine land plan. 756.15 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756...Required amendments to the Navajo Nation's abandoned mine land plan. Pursuant...

2014-07-01

143

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

Code of Federal Regulations, 2011 CFR

...Required amendments to the Navajo Nation's abandoned mine land plan. 756.15 Section... INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756...Required amendments to the Navajo Nation's abandoned mine land plan. Pursuant...

2011-07-01

144

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

Code of Federal Regulations, 2010 CFR

...regulating activities on the Navajo Partitioned Lands, including tribal laws relating to land use, environmental protection, and historic or...tribal laws pertaining to the Navajo Partitioned Lands, BIA will: (1) Assist in the...

2010-04-01

145

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

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false How will tribal laws be enforced on the Navajo Partitioned Lands...LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.101 How will tribal laws be enforced on the Navajo Partitioned...

2011-04-01

146

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

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false How will tribal laws be enforced on the Navajo Partitioned Lands...LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.101 How will tribal laws be enforced on the Navajo Partitioned...

2013-04-01

147

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

Code of Federal Regulations, 2012 CFR

... 2011-04-01 true How will tribal laws be enforced on the Navajo Partitioned Lands...LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.101 How will tribal laws be enforced on the Navajo Partitioned...

2012-04-01

148

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

... 2014-04-01 false How will tribal laws be enforced on the Navajo Partitioned Lands...LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.101 How will tribal laws be enforced on the Navajo Partitioned...

2014-04-01

149

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

150

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

151

78 FR 41012 - Approval of Air Quality Implementation Plans; Navajo Nation; Regional Haze Requirements for...  

Federal Register 2010, 2011, 2012, 2013

...Navajo Generating Station; Extension of...Navajo Generating Station (NGS), located...period to allow time for stakeholders...your identity or contact information unless...FURTHER INFORMATION CONTACT: Anita Lee...allow stakeholders time to develop alternatives...Navajo Generating Station Docket No....

2013-07-09

152

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

SciTech Connect

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

Ahlbrandt, T.S. [Geological Survey, Denver, CO (United States); Fox, J.E. [South Dakota School of Mines, Rapid City, SD (United States)

1997-07-01

153

78 FR 2685 - Notice of Intent To Prepare a Programmatic Environmental Impact Statement (EIS) for the Navajo...  

Federal Register 2010, 2011, 2012, 2013

...EIS) for the Navajo Nation Integrated Weed Management Plan Within Coconino, Navajo...intends to prepare an EIS for a proposed weed management plan for the Navajo Indian Reservation...proposing to develop a ten-year integrated weed management plan for the Navajo Indian...

2013-01-14

154

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

E-print Network

emission gun scanning electron microscope (FEG- SEM). Here, we report the first HRTEM observation of a 10: Electron microscopic characterization Chen Zhu a,*, David R. Veblen b , Alex E. Blum c , Stephen J. Chipera, was characterized with high-reso- lution transmission and analytical electron microscope (HRTEM-AEM) and field

Zhu, Chen

155

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

SciTech Connect

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

Thomas Benally, Deputy Director,

2012-05-15

156

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

USGS Publications Warehouse

The bedrock and surficial geologic map of the west half of the Sanders 30' x 60' quadrangle was completed in a cooperative effort of the U.S. Geological Survey (USGS) and the Navajo Nation to provide regional geologic information for management and planning officials. This report provides baseline geologic information that will be useful in future studies of groundwater and surface water resources, geologic hazards, and the distribution of soils and plants. The west half of the Sanders quadrangle encompasses approximately 2,509 km2 (980 mi2) within Navajo and Apache Counties of northern Arizona and is bounded by lat 35°30' to 35° N., long 109°30' to 110° W. The majority of the land within the map area lies within the Navajo Nation. South of the Navajo Nation, private and State lands form a checkerboard pattern east and west of Petrified Forest National Park. In the west half of the Sanders quadrangle, Mesozoic bedrock is nearly flat lying except near folds. A shallow Cenozoic erosional basin that developed about 20 Ma in the western part of the map area cut across late Paleozoic and Mesozoic rocks that were subsequently filled with flat-lying Miocene and Pliocene mudstone and argillaceous sandstone and fluvial sediments of the Bidahochi Formation and associated volcanic rocks of the Hopi Buttes volcanic field. The Bidahochi rocks are capped by Pliocene(?) and Pleistocene fluvial sediments and Quaternary eolian and alluvial deposits. Erosion along northeast-southwest-oriented drainages have exposed elongated ridges of Bidahochi Formation and basin-fill deposits that are exposed through shallow eolian cover of similarly oriented longitudinal dunes. Stokes (1964) concluded that the accumulation of longitudinal sand bodies and the development of confined parallel drainages are simultaneous processes resulting in parallel sets of drainages and ridges oriented along the prevailing southwest wind direction on the southern Colorado Plateau.

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

2014-01-01

157

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

158

A Jurassic mammal from South America  

Microsoft Academic Search

The Jurassic period is an important stage in early mammalian evolution, as it saw the first diversification of this group, leading to the stem lineages of monotremes and modern therian mammals. However, the fossil record of Jurassic mammals is extremely poor, particularly in the southern continents. Jurassic mammals from Gondwanaland are so far only known from Tanzania and Madagascar, and

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

2002-01-01

159

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

160

Technical Review of the Navajo Nation Drought Contingency  

E-print Network

Technical Review of the Navajo Nation Drought Contingency Plan ­ Drought Monitoring Michael-term Drought 7 Current Drought Monitoring Procedures: An examination of the 6-month SPI Drought Index 8 SPI and Drought Monitoring: Shorter vs. longer timescales 9 A Closer Look at the 6-month SPI 10 Precipitation

Neff, Jason

161

Origin of coexisting minette and ultramafic breccia, Navajo volcanic field  

Microsoft Academic Search

Trace element evidence indicates that at the Buell Park diatreme, Navajo volcanic field, the felsic minette can be best explained by crystal fractionation from a potassic magma similar in composition to the mafic minettes. Compatible trace element (Cr, Ni, Sc) abundances decrease while concentrations of most incompatible elements (Ce, Yb, Rb, Ba, Sr) remain constant or increase from mafic to

Michael F. Roden

1981-01-01

162

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

163

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

164

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.

165

Politics of Local Control: Ramah Navajo Community Forms a School.  

ERIC Educational Resources Information Center

For more than 100 years the Native Americans of the U.S. have been dominated economically, socially, educationally, and culturally by the larger society in which they live. The U.S. government has set policies, primarily through the Bureau of Indian Affairs (BIA), without consulting Native Americans. The Ramah Navajo Community experienced…

Norris, Robert

166

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

167

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

NASA Astrophysics Data System (ADS)

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

Chamberlain, Kathleen Patricia

1998-11-01

168

Lichen on Sandstone  

USGS Multimedia Gallery

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

169

Sandstone and Moon  

USGS Multimedia Gallery

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

170

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

171

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

SciTech Connect

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

White, J.D.L. (Dalhousie Univ., Halifax, Nova Scotia (Canada)); Vallier, T. (Geological Survey, Menlo Park, CA (United States)); Stanley, G.D. Jr. (Univ. of Montana, Missoula (United States)); Ash, S.R. (Weber State Univ., Odgen, UT (United States)); White, D.L.

1992-08-01

172

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

SciTech Connect

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

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

1989-05-01

173

Lessons from the Navajo: Assistance with Environmental Data Collection Ensures Cultural Humility and Data Relevance  

PubMed Central

Background The Navajo Nation suffers from a legacy of environmental pollution from historical uranium mining activities, resulting in adverse public health outcomes and continuous exposure. Objective Partner with a Navajo graduate student and community members in a field campaign to characterize the spatial distribution and geochemistry of uranium for a multipathway uranium exposure assessment under development by the Dine Network for Environmental Health (DiNEH) project. Methods Attend community meetings, acquire Navajo language skills, and integrate local knowledge into sampling approach of sediment, water, and vegetation. Results Navajo participation (1) helped to foster trust in research efforts during community interactions, (2) taught aspects of Navajo culture and language to maintain positive and respectful relations, and (3) conveyed information on Navajo culture that would impact sampling strategies. Conclusions Community engagement helps to sustain equitable partnerships and aids in culturally appropriate, relevant data collection. PMID:19655034

deLemos, Jamie; Rock, Tommy; Brugge, Doug; Slagowski, Naomi; Manning, Thomas; Lewis, Johnnye

2008-01-01

174

Diagenesis in porosity evolution of opening-mode fractures, Middle Triassic to Lower Jurassic La Boca Formation, NE Mexico  

Microsoft Academic Search

Opening-mode fractures (joints) in Middle Triassic to Lower Jurassic La Boca Formation sandstones, northeastern Mexico, have patterns of fracture porosity, mineral-fill structures, and size distributions not previously described from outcrop. Patterns match those found in cores from many basins. We used aperture measurements along lines of observation (scanlines), fracture-trace maps, petrography, high-resolution scanning-electron-microscope-(SEM)-based cathodoluminescence, and fluid inclusions to characterize fracture

Stephen E. Laubach; Meghan E. Ward

2006-01-01

175

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

176

Probable distribution of Upper Jurassic and Lower Cretaceous deposits on the Laptev Sea shelf and their petroleum resource potential  

NASA Astrophysics Data System (ADS)

The analysis of Upper Jurassic and Lower Cretaceous marine sections developed in surrounding structures of the Laptev Sea revealed that all of them are composed of terrigenous rocks, which enclose abundant concretions cemented by calcareous material. The Upper Jurassic portion of the section is the most variable in thickness and stratigraphic range of sediments usually including hiatuses. Its Lower Cretaceous part represented by the Boreal Berriasian (=Ryazanian) and lower Valanginian stages is most complete. The Upper Jurassic and Lower Cretaceous sections are usually composed of fine-grained rocks (clays and mudstones) in the west and coarser cemented varieties (siltstones and sandstones) with rare mudstone intercalations in the east. Practically all the investigated Upper Jurassic and Lower Cretaceous sections include readily recognizable age and facies analogs of the Bazhenovo Formation and Achimov sandstones, which are petroliferous in West Siberia. There are grounds to assume the occurrence of these formations also on the Laptev Sea shelf, which is confirmed by seismic records. Conditions favorable for the formation of potential hydrocarbon reservoirs could exist in the western part of the paleobasin along the Nordvik Peninsula coast and northeastern Tamyr Peninsula margin. Paleotectonic reconstructions presented in this work are well consistent with stratigraphic conclusions.

Zakharov, V. A.; Kim, B. I.; Rogov, M. A.

2013-09-01

177

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

NASA Astrophysics Data System (ADS)

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

Anderson, Jae R.

178

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

179

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

SciTech Connect

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

Turner-Peterson, C.E.; Fishman, N.S. (Geological Survey, Denver, CO (USA))

1989-09-01

180

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

Microsoft Academic Search

Sandstone-type uranium deposits usually exist in coal measures. This stratigraphy study found that the Jurassic coal measures (Shuixigou Group) at the southwest margin of the Turpan-Hami Basin consist of the Badaowan, Sangonghe and Xishanyao formations, which correspond to sequences A, B and C, respectively. Sequence C can be divided into the lowstand systems tract (LST), expanding lacustrine systems tract (EST)

Liqun Wu; Yangquan Jiao; Mason Roger; Shengke Yang

2009-01-01

181

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

182

Log interpretation of shaly sandstones  

E-print Network

-sandstone equations, 1) "practical" equations requiring only well logs, and 2) "theoretical" equations requiring additional examination of coze. This study has focused on the practical equations because of their wider applicability. These equations are based... of the sandstone. To find the CEC of the sandstone, the CEC of the clay was multiplied by the volume of clay as determined from well logs. Shale Volume The fractional volume of clay was found from the gamma 47 zay by using the Dresser Atlas fozmula...

Baker, Joel Foster

2012-06-07

183

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

ERIC Educational Resources Information Center

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

Shreve, Bradley Glenn

2006-01-01

184

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

SciTech Connect

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

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

1988-09-01

185

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

ERIC Educational Resources Information Center

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

Webster, Anthony K.

2011-01-01

186

78 FR 16825 - Approval of Air Quality Implementation Plans; Navajo Nation; Regional Haze Requirements for...  

Federal Register 2010, 2011, 2012, 2013

...Navajo Generating Station; Extension of Comment...Navajo Generating Station (NGS), located...90 days to allow time for interested parties...your identity or contact information unless...FURTHER INFORMATION CONTACT: Anita Lee, EPA...significant amount of time. On February...

2013-03-19

187

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

Federal Register 2010, 2011, 2012, 2013

...for Navajo Generating Station; Notice of Intent To...the Navajo Generating Station (NGS), located on...comment period to allow time for stakeholders to develop...public hearings at a later time in the Federal Register...FOR FURTHER INFORMATION CONTACT: Anita Lee, EPA...

2013-06-19

188

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

189

Personality Differences between Navajo and Non-Indian College Students: Implications for Instruction.  

ERIC Educational Resources Information Center

Compares the personality types of a sample of 164 Navajo community college students with those of non-Indians using the Myers-Briggs Type Indicator (MBTI). Applies research on the preferred instructional methods associated with MBTI personality types to the needs of Navajo students. (FMW)

Huitt, William G.

1988-01-01

190

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.

191

Rulers of the Jurassic Seas  

NSDL National Science Digital Library

Available free from Scientific American's Website, this article takes a thorough and fascinating look at the marine reptiles known as Ichthyosaurs that lived during the Mesozoic Era. The text covers recent discoveries about the evolution of Ichthyosaurs from land dwelling reptiles, including limb adaptations. Highlights of the article are special sections about ichthyosaur eyes and diet, and color illustrations and diagrams. The text contains hyperlinks to related pages (Britannica.com, Tree of Life, American Cetacean Society, etc.). "Rulers of the Jurassic Seas" is a good read for students of paleontology or marine science.

Motani, Ryosuke.

2000-01-01

192

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

ERIC Educational Resources Information Center

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

Goodman, James M.

193

Sandstone Cliff in Capitol Reef  

USGS Multimedia Gallery

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

194

Sandstone Cliffs in Capitol Reef  

USGS Multimedia Gallery

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

195

Sandstone Spire in Capitol Reef  

USGS Multimedia Gallery

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

196

Sandstone Monolith in Capitol Reef  

USGS Multimedia Gallery

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

197

Sandstone Adherence in Building Construction  

Microsoft Academic Search

This study analyzes bonding properties of porous sandstone to conclude that adherence between porous sandstone panels and their background supports, in building construction, can be substantially improved by applying adhesive primers at the rear of the panels. Two types of primers have been studied: styrene-butadiene latex and epoxy-resin. Laboratory tests have shown a bonding strength increase by applying both products.

Carmen Vielba-Cuerpo; Francisco Hernández-Olivares

2012-01-01

198

Strategies for assessing EarlyMiddle (PliensbachianAalenian) Jurassic  

E-print Network

cyclostratigraphy of the Jurassic Period. First, Jurassic geochronology is not well constrained, due to a generalStrategies for assessing Early­Middle (Pliensbachian­Aalenian) Jurassic cyclochronologies By Linda in stratigraphic constraints. These problems are particularly troublesome in the Early to Middle Jurassic cyclic

199

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

200

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

201

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

202

A Jurassic mammal from South America.  

PubMed

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

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

2002-03-14

203

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

204

Carbohydrate biofuels II: The need and the potential for rootfuel in the Navajo Nation  

SciTech Connect

Over 80% of rural Navajos and about two-thirds of all Navajos use scarce woodfuel and low-grade coal for home heating half the year, with coal used mainly as a nighttime adjunct. Serious health problems arise because stoves are old and leak smoke and carbon monoxide. The impacts are gender-biased to women and small children. Respiratory disease is a major cause of Navajo mortality and unusually high admissions to Navajo Indian Health Service hospitals. A 1990 study at a Navajo hospital showed that Navajo children under two years of age from homes with woodstoves are nearly five times more likely to contract acute lower respiratory tract infections than children from homes with no stove. Correctives include improved stoves and fuels. Our previous studies on clean-burning starchy/cellulosic {open_quotes}rootfuels{close_quotes} in Latin America, Africa, and Asia are applicable. We discuss our preliminary work on the Navajo reservation, the current status of household stoves and stovefuels, the health impacts of woodsmoke and coalsmoke from old, faulty stoves, the conditions for growing rootfuel on the reservation, and policy and strategy for coping with the problem.

Shultz, E.B.; Jr.; Bragg, W.G. [Enable International, Wheaton, IL (United States); Whittier, J. [NEOS Corp., Lakewood, CO (United States)] [and others

1995-11-01

205

Stochastic reconstruction of sandstones C. Manwart,1  

E-print Network

Stochastic reconstruction of sandstones C. Manwart,1 S. Torquato,2 and R. Hilfer1,3 1 Institut fu to generate a stochastic model for a Berea sandstone and a Fontainebleau sandstone, with each a prescribed two and the original sandstones. Also, the mean survival time of a random walker in the pore space is reproduced

Torquato, Salvatore

206

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

NASA Astrophysics Data System (ADS)

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

Palacios García, N. B.; Martini, M.

2012-04-01

207

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. PMID:20671946

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

2010-01-01

208

The U-Pb age dating of detrital zircons from Upper Jurassic-Lower Cretaceous deposits of Stolbovoy Island (New Siberian Islands)  

NASA Astrophysics Data System (ADS)

The results of the U-Pb (SIMS and LA-ICPMS) age dating of detrital zircons from Upper Jurassic-Lower Cretaceous sandstones of Stolbovoy Island show that these deposits contain zircons of a wide age range, from Archean to Lower Cretaceous. Precambrian gneisses and granites, as well as Late Paleozoic and Mesozoic plutonic and volcanic complexes, are considered to be the main source areas of clastic material of Upper Jurassic-Lower Cretaceous formations of Stolbovoy Island. The U-Pb age dating of detrital zircons from sandstones without making a selection on any basis yields the most complete information about source areas of clastic material in a sedimentary basin. In some cases the data on euhedral (idiomorphic) and transparent zircon crystals can be useful to clarify the lower age boundary of sedimentation.

Soloviev, A. V.; Miller, E. L.

2014-09-01

209

Sandstone Formations in Capitol Reef  

USGS Multimedia Gallery

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

210

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

SciTech Connect

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

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

1991-03-01

211

World petroleum systems with Jurassic source rocks  

SciTech Connect

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

Klemme, H.D. (Geo Basins Ltd., Bondville, VT (United States))

1993-11-08

212

Jurassic-Neocomian biostratigraphy, North Slope, Alaska  

SciTech Connect

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

Mickey, M.B.; Haga, H.

1985-04-01

213

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

SciTech Connect

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

Mink, R.M.; Mancini, E.A. [Geological Survey of Alabama, Tuscaloosa, AL (United States)

1995-10-01

214

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

Code of Federal Regulations, 2011 CFR

...amendments to the Navajo Nation's abandoned mine land plan. 756.14 Section 756.14 Mineral...ENFORCEMENT, DEPARTMENT OF THE INTERIOR INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.14...

2011-07-01

215

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

Code of Federal Regulations, 2010 CFR

...amendments to the Navajo Nation's abandoned mine land plan. 756.14 Section 756.14 Mineral...ENFORCEMENT, DEPARTMENT OF THE INTERIOR INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.14...

2010-07-01

216

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

Code of Federal Regulations, 2012 CFR

...amendments to the Navajo Nation's abandoned mine land plan. 756.14 Section 756.14 Mineral...ENFORCEMENT, DEPARTMENT OF THE INTERIOR INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.14...

2012-07-01

217

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

Code of Federal Regulations, 2013 CFR

...amendments to the Navajo Nation's abandoned mine land plan. 756.14 Section 756.14 Mineral...ENFORCEMENT, DEPARTMENT OF THE INTERIOR INDIAN LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.14...

2013-07-01

218

78 FR 58987 - Approval of Air Quality Implementation Plans; Navajo Nation; Regional Haze Requirements for...  

Federal Register 2010, 2011, 2012, 2013

...group of stakeholders known as the Technical Work Group (TWG) and consisting of the CAWCD, the Environmental Defense Fund (EDF), Gila River, Navajo Nation, SRP, on behalf of itself and the other non-federal Participants, Interior, and...

2013-09-25

219

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

Code of Federal Regulations, 2010 CFR

...Indian lands—Class II wells. The UIC program for Class II injection wells located: Within...SDWA for Class II injection wells on Navajo Indian...For information on the availability of this material at...

2010-07-01

220

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

...and 1 CFR part 51. Copies may be obtained or inspected at the Navajo Nation Environmental Protection Agency UIC Office, Old NAPA Auto Parts Building (Tribal Bldg. #S009-080), Highway 64, Shiprock, New Mexico 87420...

2014-07-01

221

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

Code of Federal Regulations, 2012 CFR

...and 1 CFR part 51. Copies may be obtained or inspected at the Navajo Nation Environmental Protection Agency UIC Office, Old NAPA Auto Parts Building (Tribal Bldg. #S009-080), Highway 64, Shiprock, New Mexico 87420...

2012-07-01

222

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

Code of Federal Regulations, 2013 CFR

...and 1 CFR part 51. Copies may be obtained or inspected at the Navajo Nation Environmental Protection Agency UIC Office, Old NAPA Auto Parts Building (Tribal Bldg. #S009-080), Highway 64, Shiprock, New Mexico 87420...

2013-07-01

223

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

224

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

225

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

226

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

USGS Publications Warehouse

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

Sanford, R.F.

1994-01-01

227

Sequence architecture and lithofacies assemblages of submarine fan deposits in Los Molles Formation (Jurassic), Neuquen Basin, Argentina  

SciTech Connect

The Neuquen basin is a remnant of the Mesozoic back-arc basin trend that developed along the western margin of South America. It contains a thick, diverse sequence of Jurassic sedimentary strata, whose facies distribution was strongly influenced by syndepositional tectonism. The predominantly dark, laminated shales and siltstones of the Los Molles Formation range from Pliensbachian to Callovian in age and record the progradation of the outer shelf, slope, and basin-plain sediments deposited during the shoaling phase of the lowermost, or Cuyan, Jurassic cycle. Based on outcrop, well, and seismic data, several thick packages of sandstone and conglomerate within the Los Molles are interpreted to represent submarine fan deposits that developed during periods of relative sea level lowstand. Sea level falls were probably related to local synchronous tectonic pulses rather than true eustatic fluctuations. The distribution of coarse-grained fan deposits was apparently strongly controlled by the location of major Jurassic fault trends that stabilized the position of the shelf-slope break through time. Based on the geometry and sequence architecture, two distinct styles of fan development are recognized in the Los Molles sandstones. The most common style (type A) is characterized by sequences that have poorly defined, sand-poor lobes with well-developed channel-levee complexes. Some channels exhibit large-scale accretion surfaces, probably resulting from lateral migration. Thick-bedded arenite facies are limited to amalgamated channel fills, whereas thin-bedded classical turbidites are present as overbank deposits. Type A fans were built by turbidity and fluxoturbidity currents from submarine canyon point sources. The less common fan sequences (type B) lack channeling; they are dominated by thick, massive beds of internally featureless sandstone that are bounded by chaotic slump deposits.

Dean, J.S.

1986-05-01

228

Jurassic igneous-related metallogeny of southwestern North America  

E-print Network

Jurassic igneous-related metallogeny of southwestern North America Mark D. Barton*, James D Jurassic magmatism and related hydrothermal systems formed across much of southwestern North America, advanced argillic, metallogeny, magmatism, southwestern North America INTRODUCTION The Great Basin

Barton, Mark D.

229

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

SciTech Connect

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

Meyers, J.H. (Winona State Univ., MN (United States). Dept. of Geology); O'Malley, P.J. (Indiana Univ., Bloomington, IN (United States). Dept. of Geosciences)

1993-04-01

230

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

231

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

232

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

233

Running head: Diagenesis of Beacon Sandstone Diagenetic history of Triassic sandstone from the Beacon Supergroup in  

E-print Network

1 Running head: Diagenesis of Beacon Sandstone Diagenetic history of Triassic sandstone from sandstone from the Beacon Supergroup, Victoria Land, Antarctica, can be divided into three main phases-temperature diagenetic phase is dominated by zeolite cementation, even in sandstone poor in zeolite precursor materials

Boyer, Edmond

234

Early Jurassic Insects from the Newark Supergroup, Northeastern  

E-print Network

13 Early Jurassic Insects from the Newark Supergroup, Northeastern United States Phillip Huber, Nicholas G. McDonald, and Paul E. Olsen F ossil insects from the Early Jurassic (Hettan- gian in this chapter constitutes the only record of Jurassic insects from North America. Lower Mesozoic sedimentary

Olsen, Paul E.

235

Late Jurassic salamandroid from western Liaoning, China  

PubMed Central

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 (40Ar/39Ar dates of 122–129 Ma), but slightly younger than the Middle Jurassic Daohugou horizon (40Ar/39Ar 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.

2012-01-01

236

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

237

Permeability Evolution during Deformation of Siliciclastic Sandstones  

E-print Network

Permeability Evolution during Deformation of Siliciclastic Sandstones from Moab, Utah O. Kwon1 Core; 0.33-ft)- diameter cores of four sandstones from the Moab area to investigate the effect of total. Sandstones with low bulk porosities (Dewey Bridge and Slickrock Subkha) exhibited an increase in permeability

238

IMPROVING SANDSTONE MATRIX STIMULATION OF OIL  

E-print Network

IMPROVING SANDSTONE MATRIX STIMULATION OF OIL WELLS BY GAS PRECONDITIONING M. A. Aggour, M. Al, Dhahran, Saudi Arabia ABSTRACT Experience has shown that for sandstone formations, oil wells respond wells. It is, therefore, expected that stimulation of oil wells in sandstone formations could

Abu-Khamsin, Sidqi

239

Evaluating Reading Materials in Navajo: Report of a Teachers' Conference (Gallup, New Mexico, April 28-29, 1972). Navajo Reading Study Progress Report No. 18.  

ERIC Educational Resources Information Center

Elementary-grade reading materials produced in the Navajo language were evaluated at a teacher's conference held in Gallup, New Mexico, on April 28-29, 1972. Participants, mostly teachers, at the conference numbered approximately 45. The 5 texts evaluated were "Mosilgai" (School Cat), "Jasper," Pabii Doo Masi" (Puppy and Cat), "Da'iida" (Eat), and…

Gradman, Harry L.; Young, Robert W.

240

A New Classification of Sandstone.  

ERIC Educational Resources Information Center

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

Brewer, Roger Clay; And Others

1990-01-01

241

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

242

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

243

A Feasibility Study to Evaluate Wind Energy Potential on the Navajo Nation  

SciTech Connect

The project, A Feasibility Study to Evaluate Wind Energy Potential on the Navajo Nation, is funded under a solicitation issued by the U.S. Department of Energy Tribal Energy Program. Funding provided by the grant allowed the Navajo Nation to measure wind potential at two sites, one located within the boundaries of the Navajo Nation and the other off-reservation during the project period (September 5, 2005 - September 30, 2009). The recipient for the grant award is the Navajo Tribal Utility Authority (NTUA). The grant allowed the Navajo Nation and NTUA manage the wind feasibility from initial site selection through the decision-making process to commit to a site for wind generation development. The grant activities help to develop human capacity at NTUA and help NTUA to engage in renewable energy generation activities, including not only wind but also solar and biomass. The final report also includes information about development activities regarding the sited included in the grant-funded feasibility study.

Terry Battiest

2012-11-30

244

"Enemies Like a Road Covered with Ice": The Utah Navajos' Experience during the Long Walk Period, 1858-1868  

ERIC Educational Resources Information Center

Much has been written of the Navajo Long Walk period when the Navajo people, following what appears to be a fairly short resistance, surrendered in droves to the US military, collected at Fort Defiance and other designated sites, then moved in a series of "long walks" to Fort Sumner (Hweeldi) on the Pecos River in eastern New Mexico. There was…

Hornsby, Sarah; McPherson, Robert S.

2009-01-01

245

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

246

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

247

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

248

Jurassic stratigraphy of the Wiggins Arch, Mississippi  

SciTech Connect

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

Rhodes, J.A.; Maxwell, G.B. (Mobil Oil Company, Houston, TX (United States))

1993-09-01

249

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

250

Late Jurassic deformation in Honduras. Proposals for a revised regional stratigraphy  

NASA Astrophysics Data System (ADS)

The lithostratigraphical subdivision of Mesozoic rocks in Honduras poses problems that are still imperfectly resolved. Observations made by the authors in Honduras between 1988 and 1992, show a clear separation between an older detrital unit, locally known as the Agua Fria Formation which is relatively homogeneous and can be found throughout the so-called Chortis Block, and a younger one composed essentially of cyclic detrital deposition (conglomerates and other molasse type rocks grading into pelites and silstones), usually called red beds ("capas rojas"). The older detrital unit, here called the Honduras Group, is an Early to Middle Jurassic folded and locally metamorphosed unit. The younger unit known as "capas rojas" starts with a molasse type rock which is not metamorphosed and presently have no generic name, and was deposited in extensional basins during a second sedimentary cycle of Early (and younger?) Cretaceous age. Between the two cycles a clear deformation phase took place in the late Jurassic. At La Chacra, near Comayagua in the centre of the country, outcrop conditions and exploration data enabled the observation of a composite section through the lithostratigraphic succession of the two Mesozoic cycles. The following succession was observed from bottom to top: • Schist and conglomerate of the Agua Fria Formation, turned to a near-vertical position, which was intruded by granite and mineralized veins that are considered to have a late magmatic (Late Jurassic) age. • A paleo-erosion surface over the Agua Fria Formation, shown by the presence of discordant weathering phenomena and a palaeosol. • Detrital deposits (calcareous sandstone) and carbonate rocks of the Cretaceous cycle (molasse and red beds of the second cycle), which unconformably overlie the rocks of the first cycle. These observations confirm the existence, in Honduras and throughout the Chortis Block, of two distinct depositional cycles of Mesozoic age that were separated by a major crustal-deformation phase of Late Jurassic age. The same features are known from central Mexico, whence the Chortis Block seems to have come according to generally admitted crustal-block reconstructions of Central America. Early Cretaceous deposits in Honduras fill Cretaceous graben of the central zone. Although superficially resembling the (Triassic-Jurassic) Todos Santos Formation in Mexico and Guatemala, they cannot be compared with this unit because of their different age and origin, and will require better definition and a new name in Honduras.

Viland, J. C.; Henry, B.; Calix, R.; Diaz, C.

1996-07-01

251

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

252

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

253

Sequence stratigraphy of middle and upper Jurassic strata of Southwestern Alabama  

SciTech Connect

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

Wade, W.J.; Moore, C.H. Jr. (Louisiana State Univ., Baton Rouge, LA (United States))

1993-09-01

254

ELASTIC ROCK PROPERTIES OF TIGHT GAS SANDSTONES FOR RESERVOIR CHARACTERIZATION  

E-print Network

ELASTIC ROCK PROPERTIES OF TIGHT GAS SANDSTONES FOR RESERVOIR CHARACTERIZATION AT RULISON FIELD, and lithology changes on tight gas sandstones. The rock physics of tight gas sandstones (low permeability sandstone reservoirs. However, very little work has been done in tight gas sandstones. In this work, rock

255

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

USGS Publications Warehouse

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

Lillis, Paul G.; King, J. David

2007-01-01

256

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

SciTech Connect

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

Muto, T. [Nagasaki Univ. (Japan); Steel R.J. [Univ. of Wyoming, Laramie, WY (United States)

1997-07-01

257

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

258

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

259

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

260

A Ten-Year Plan for Indian Education: With Particular Reference to Navajo Community Schools.  

ERIC Educational Resources Information Center

The 10-year plan for American Indian Education, though overall in its intent, is presented with special reference to the Community Schools on the Navajo Reservation. The plan is based on convictions that facility in the use of the English language is a prime necessity for both children and adults; that a continually enriched environment is…

Stout, Irving W.

261

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

262

Of Mother Earth and Father Sky: A Photographic Study of Navajo Culture.  

ERIC Educational Resources Information Center

Utilizing 52 black and white photographs, the book tells a story about the Navajo people, their hopes and problems, the strategies they have adopted to cope with the problems, their interactions with each other and with the land, and their feelings about the land which provides a basis for their livelihood. Part of a series of curriculum materials…

McCarty, T. L.; And Others

263

The Navajo Learning Network and the NASA Life Sciences/AFOSR Infrastructure Development Project  

NASA Technical Reports Server (NTRS)

The NSF-funded Navajo Learning Network project, with help from NASA Life Sciences and AFOSR, enabled Dine College to take a giant leap forward technologically - in a way that could never had been possible had these projects been managed separately. The combination of these and other efforts created a network of over 500 computers located at ten sites across the Navajo reservation. Additionally, the college was able to install a modern telephone system which shares network data, and purchase a new higher education management system. The NASA Life Sciences funds further allowed the college library system to go online and become available to the entire campus community. NSF, NASA and AFOSR are committed to improving minority access to higher education opportunities and promoting faculty development and undergraduate research through infrastructure support and development. This project has begun to address critical inequalities in access to science, mathematics, engineering and technology for Navajo students and educators. As a result, Navajo K-12 education has been bolstered and Dine College will therefore better prepare students to transfer successfully to four-year institutions. Due to the integration of the NSF and NASA/AFOSR components of the project, a unified project report is appropriate.

1999-01-01

264

The Economic Contributions of Women in a Rural Western Navajo Community.  

ERIC Educational Resources Information Center

Examines and enumerates economic changes that have occurred in the traditional rural Navajo community of Shonto. While women's net income contributions to Shonto's economy has declined, their position has seen only a slight erosion; their activities (sheep and goat husbandry, agriculture, arts and crafts) are still considered necessary and…

Russell, Scott C.; McDonald, Mark B.

1982-01-01

265

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

266

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

267

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

Code of Federal Regulations, 2011 CFR

...1 CFR part 51. Copies may be obtained or inspected at the Navajo Nation Environmental Protection Agency UIC Office, Old NAPA Auto Parts Building (Tribal Bldg. #S009-080), Highway 64, Shiprock, New Mexico 87420 (505-368-1040), at the...

2011-07-01

268

Improving residential coal stoves: Air quality issues on the Navajo Reservation and the implications for China  

SciTech Connect

This is a report of a one-year, Laboratory-Directed Research and Development (LDRD) program development (PD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to evaluate the environmental impacts of home-scale coal combustion on the Navajo Reservation and develop strategies to reduce adverse health effects associated with home-scale coal combustion. Principal accomplishments of this project were: (1) determination of the metal and gaseous emissions of a representative stove on the Navajo Reservation; (2) recognition of cyclic gaseous emissions in combustion in home-scale combustors; (3) back of the envelope calculation that home-scale coal combustion may impact Navajo health; and (4) identification that improved coal stoves require the ability to burn diverse feedstocks (coal, wood, biomass). Ultimately the results of Navajo home-scale coal combustion studies will be extended to the Developing World, particularly China, where a significant number (> 150 million) of households continue to utilize low-grade coal in their homes.

Goff, S.J.; Hickmott, D.D.; Brown, L.F.; Currier, R.P.; Thayer, G.R. [Los Alamos National Lab., NM (United States); Semken, S.C.; Lameman, T.; Martin, S.; Yazzie, S. [Navajo Community Coll., Shiprock, NM (United States)

1997-12-31

269

Cross Country, Rodeo, Archery: Navajo Athletic Programs Give Students Running Start  

ERIC Educational Resources Information Center

While tribal college athletic programs were not designed to market the colleges, there is no denying they have generated positive attention and have perhaps even helped to highlight the colleges' purpose. Dine College and Navajo Technical College are among a handful of tribal colleges who have made athletic programs a priority. They have since…

Johnson, Natasha Kaye

2009-01-01

270

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

271

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...

272

New Late Jurassic palaeomagnetic data from the northern Sichuan basin: implications for the deformation of the Yangtze craton  

NASA Astrophysics Data System (ADS)

Upper Jurassic red sandstones and red siltstones were collected from 67 layers at 12 localities in the Penglaizhen formation. This formation is in the north of Bazhong county (31.8 degN, 106.7 degE) in the Sichuan basin, which is located in the northern part of the Yangtze craton. Thermal demagnetization isolated a high-temperature magnetic component with a maximum unblocking temperature of about 690 degC from 45 layers. The primary nature of the magnetization acquisition is ascertained through the presence of magnetostratigraphic sequences with normal and reversed polarities, as well as positive fold and reversal tests at the 95 per cent confidence level. The tilt-corrected mean direction of 36 layers is D=20.0 deg, I=28.8 deg with ?95=5.8 deg. A Late Jurassic palaeomagentic pole at 64.7 degN, 236.0 degE with A95=7.0 deg is calculated from the palaeomagnetic directions of 11 localities. This pole position agrees with the two other Late Jurassic poles from the northern part of the Yangtze craton. A characteristic Late Jurassic pole is calculated from the three poles (68.6 degN, 236.0 degE with A95=8.0 deg) for the northern part of the Yangtze craton. This pole position is significantly different from that for the southern part of the Yangtze craton. This suggests that the southern part of the Yangtze craton was subjected to southward extrusion by 1700+/-1000 km with respect to the northern part. Intracraton deformation occurred within the Yangtze craton.

Yokoyama, Masahiko; Liu, Yuyan; Otofuji, Yo-ichiro; Yang, Zhenyu

1999-12-01

273

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

274

Depositional and diagenetic control on porosity and permeability in deeply-buried sandstone reservoirs as exemplified by North Sea data  

SciTech Connect

Burial diagenesis and reservoir quality modification in North Sea Jurassic reservoirs are shown to be largely controlled by the pre-burial composition of the sandstones. Mechanical compaction at shallow burial, chemical compaction and quartz cementation at deep burial, and clay mineral authigenesis are the three most important reservoir quality modifying diagenetic processes, and all these can largely be considered as being isochemical or partially isochemical. It follows that reservoir quality prediction will be successful if the initial mineralogy and texture of the reservoir rocks, the quantitative effects of changing rock composition, and the burial history are known. Although a highly accurate prediction of initial sandstone composition is rarely achievable, an understanding of the effect of varying mineralogy on the most important reservoir quality modifying processes will in most cases provide the necessary basis for adequate reservoir quality prediction. The initial composition of the sandstones is controlled by the sedinmentological environment, depositional processes, climate and the type of material transported into the sedimentary basin. Hence, integrated sedimentological and petrological studies, addressing the links between three-dimensional distributions of depositional facies, initial sandstone composition and reservoir quality models are the key to successful reservoir quality prediction prior to drilling in frontier areas as well as detailed reservoir characterization during field development.

Ramm, M. (Norsk Hydro Exploration and Production, Stabekk (Norway))

1996-01-01

275

Depositional and diagenetic control on porosity and permeability in deeply-buried sandstone reservoirs as exemplified by North Sea data  

SciTech Connect

Burial diagenesis and reservoir quality modification in North Sea Jurassic reservoirs are shown to be largely controlled by the pre-burial composition of the sandstones. Mechanical compaction at shallow burial, chemical compaction and quartz cementation at deep burial, and clay mineral authigenesis are the three most important reservoir quality modifying diagenetic processes, and all these can largely be considered as being isochemical or partially isochemical. It follows that reservoir quality prediction will be successful if the initial mineralogy and texture of the reservoir rocks, the quantitative effects of changing rock composition, and the burial history are known. Although a highly accurate prediction of initial sandstone composition is rarely achievable, an understanding of the effect of varying mineralogy on the most important reservoir quality modifying processes will in most cases provide the necessary basis for adequate reservoir quality prediction. The initial composition of the sandstones is controlled by the sedinmentological environment, depositional processes, climate and the type of material transported into the sedimentary basin. Hence, integrated sedimentological and petrological studies, addressing the links between three-dimensional distributions of depositional facies, initial sandstone composition and reservoir quality models are the key to successful reservoir quality prediction prior to drilling in frontier areas as well as detailed reservoir characterization during field development.

Ramm, M. [Norsk Hydro Exploration and Production, Stabekk (Norway)

1996-12-31

276

Snow-covered Sandstone at Bryce Canyon  

USGS Multimedia Gallery

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

277

Sandstone Strata in Capitol Reef National Park  

USGS Multimedia Gallery

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

278

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

NASA Astrophysics Data System (ADS)

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

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

2009-09-01

279

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

SciTech Connect

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

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

1987-05-01

280

PARTITOMORPHITAE, A NEW SUBGROUP OF TRIASSIC AND JURASSIC ACRITARCHS  

Microsoft Academic Search

Three new genera of acritarchs are described: Rugidinium, comprising two new species, R. ornatum and ,R. undulatum, from the Bajocian (Jurassic) of Canada; Thuledinium, represented by a single species, T. groenlandicum , from the Callovian (Jurassic) of Greenland; and Teichertodinium, represented by a single species, T. triassicum, from the Triassic (Anisian) of Pakistan. All three genera share the charac^ teristics

STANLEY A. J. POCOCK; WILLIAM A. S. SARJEANT

281

TriassicJurassic boundary events: Problems, progress, possibilities 1. Problems  

E-print Network

As for most geological period boundaries, the Triassic­Jurassic (T­J) transition, 200 million years agoEditorial Triassic­Jurassic boundary events: Problems, progress, possibilities 1. Problems to reconstruct past events, a physical record of their passing is essential. Here again the Triassic

McRoberts, Christopher A.

282

Massive dissociation of gas hydrate during a Jurassic  

E-print Network

.............................................................................................................................................. In the Jurassic period, the Early Toarcian oceanic anoxic event (about 183 million years ago) is associated hydrate during a Jurassic oceanic anoxic event Stephen P. Hesselbo*, Darren R. Gro¨cke*, Hugh C. Jenkyns together, these 13 C curves depict a period of gradual rise in isotopic values which is interrupted

Hesselbo, Stephen P.

283

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

284

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

285

Hydromechanical Behaviour of Fontainebleau Sandstone  

NASA Astrophysics Data System (ADS)

The hydromechanical behaviour of Fontainebleau sandstone is studied on the basis of isotropic and triaxial compression tests in drained and undrained conditions on water saturated samples. The effect of the evolution of the compressibility of the rock with the applied stress on the poromechanical parameters is shown. On the basis of micro-mechanical considerations, a new expression for the Skempton coefficient B is proposed as a function of the porosity, the drained bulk compressibility and the grain and fluid compressibility. The relation between rock deformation and pore-pressure evolution in undrained deviatoric tests is analysed. An elasto-plastic constitutive model with stress-dependent elasticity and damage is proposed to describe the behaviour of the rock and validated through back analysis of drained and undrained tests.

Sulem, J.; Ouffroukh, H.

2006-07-01

286

Exploration models for submarine slope sandstones  

SciTech Connect

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

Slatt, R.M.

1986-09-01

287

Sandstone compaction: Basis for porosity predictive capabilities  

SciTech Connect

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

Houseknecht, D.W.; Dincau, A.R.; Freeman, C.W. (Univ. of Missouri, Columbia (United States))

1991-03-01

288

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

SciTech Connect

Sandstone porosity of the Upper Jurassic Norphlet Formation in southwestern Alabama and vicinity decreases systematically as depth and thermal maturity increase over a wide range. Median porosity is about 25% where equivalent vitrinite reflectance (R[sub o]) is slightly over 0.7% in the northern part of the study area (Clarke County, Mississippi). Median porosity is reduced to 8% where R[sub o] approaches 2.7% in the southern part of the study area (state waters of Mobile Bay). Porosity of the cemented, tight zone at the top of the Norphlet in downdip locations is roughly 10% lower than porosities of facies underlying the tight zone, but nevertheless is slightly above the norm for other sandstones at similar R[sub o] levels. Porosity of dune facies is consistently 2-5% higher than that of interdune facies, other factors being equal. Our data show 3-6% higher porosity in chlorite-dominated intervals relative to intervals where illite is the dominant clay mineral. Norphlet porosity has little or no correlation with position relative to the present-day hydrocarbon-water contact. Based on comparisons at similar R[sub o] levels, median (50th-percentile) Norphlet porosity exceeds porosities of [open quotes]typical[close quotes] 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. 48 refs., 12 figs., 5 tabs.

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

1994-02-01

289

Flow focusing in overpressured sandstones: Theory, observations, and applications  

Microsoft Academic Search

Dipping permeable sandstone bodies encased in overpressured low permeability mudstone have a characteristic pressure field: sandstone pressures follow the hydrostatic gradient while mudstone pressures have a steeper (often lithostatic) gradient. This pressure distribution drives fluid into the base of the sandstone and expels it at the crest. We use mudstone pressures predicted from porosity and measured sandstone pressures to describe

PETER B. FLEMINGS; BETH B. STUMP; THOMAS FINKBEINER; MARK ZOBACK

2002-01-01

290

Loading rate dependence of permeability evolution in porous aeolian sandstones  

E-print Network

Loading rate dependence of permeability evolution in porous aeolian sandstones Ira O. Ojala, Bryne on the permeability of porous sandstones by carrying out triaxial compression tests at four different temperatures effective stress and axial strain for the Locharbriggs sandstone. The Clashach sandstone exhibits a linear

291

DEFORMATION AND FRACTURE OF POORLY CONSOLIDATED MEDIA - Borehole Failure Mechanisms in High-Porosity Sandstone  

SciTech Connect

We investigated failure mechanisms around boreholes and the formation of borehole breakouts in high-porosity sandstone, with particular interest to grain-scale micromechanics of failure leading to the hitherto unrecognized fracture-like borehole breakouts and apparent compaction band formation in poorly consolidated granular materials. We also looked at a variety of drilling-related factors that contribute to the type, size and shape of borehole breakouts. The objective was to assess their effect on the ability to establish correlations between breakout geometry and in situ stress magnitudes, as well as on borehole stability prediction, and hydrocarbon/water extraction in general. We identified two classes of medium to high porosity (12-30%) sandstones, arkosic, consisting of 50-70% quartz and 15 to 50% feldspar, and quartz-rich sandstones, in which quartz grain contents varied from 90 to 100%. In arkose sandstones critical far-field stress magnitudes induced compressive failure around boreholes in the form of V-shaped (dog-eared) breakouts, the result of dilatant intra-and trans-granular microcracking subparallel to both the maximum horizontal far-field stress and to the borehole wall. On the other hand, boreholes in quartz-rich sandstones failed by developing fracture-like breakouts. These are long and very narrow (several grain diameters) tabular failure zones perpendicular to the maximum stress. Evidence provided mainly by SEM observations suggests a failure process initiated by localized grain-bond loosening along the least horizontal far-field stress springline, the packing of these grains into a lower porosity compaction band resembling those discovered in Navajo and Aztec sandstones, and the emptying of the loosened grains by the circulating drilling fluid starting from the borehole wall. Although the immediate several grain layers at the breakout tip often contain some cracked or even crushed grains, the failure mechanism enabled by the formation of the compaction band is largely non-dilatant, a major departure from the dilatant mechanism observed in Tablerock sandstone. The experimental results suggest that unlike our previous assertion, the strength of grain bonding and the mineral composition, rather than the porosity, are major factors in the formation of compaction bands and the ensuing fracture-like breakouts. Some breakout dimensions in all rocks were correlatable to the far-field principal stresses, and could potentially be used (in conjunction with other information) as indicators of their magnitudes. However, we found that several factors can significantly influence breakout geometry. Larger boreholes and increased drilling-fluid flow rates produce longer fracture-like breakouts, suggesting that breakouts in field-scale wellbores could reach considerable lengths. On the other hand, increased drilling-fluid weight and increased drill-bit penetration rate resulted in a decrease in breakout length. These results indicate that breakout growth can be controlled to some degree by manipulating drilling variables. Realizing how drilling variables impact borehole breakout formation is important in understanding the process by which breakouts form and their potential use as indicators of the far-field in situ stress magnitudes and as sources of sand production. As our research indicates, the final breakout size and mechanism of formation can be a function of several variables and conditions, meaning there is still much to be understood about this phenomenon.

Bezalel c. Haimson

2005-06-10

292

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

293

Monitoring and analysis of sand dune movement and growth on the Navajo Nation, southwestern United States  

USGS Publications Warehouse

Recurring drought and rising temperatures have caused reactivation and renewed growth of sand dunes on the lands of the Navajo Nation on the Colorado Plateau. Migrating dunes threaten health, housing, and transportation pathways. U.S. Geological Survey (USGS) scientists are conducting research to better understand the processes of dune growth and movement. This research will provide critical data to the Native peoples of the region in their response to the changing environment.

Redsteer, Margaret Hiza; Bogle, Rian C.; Vogel, John M.

2011-01-01

294

PSYCHOLOGICAL EFFECTS OF TECHNOLOGICAL\\/HUMAN-CAUSED ENVIRONMENTAL DISASTERS: EXAMINATION OF THE NAVAJO AND URANIUM  

Microsoft Academic Search

Disasters can be defined as catastrophic events that challenge the normal range of human coping ability. The technological\\/human-caused disaster, a classification of interest in this article, is attributable to human error or misjudgment. Lower socioeconomic status and race intersect in the heightened risk for technological\\/human- caused disasters among people of color. The experience of the Navajo with the uranium industry

Carol A. Markstrom; Perry H. Charley

295

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

296

Vertebrate fossils and trace fossils in Upper Jurassic-Lower cretaceous red beds in the Atacama region, Chile  

NASA Astrophysics Data System (ADS)

Pterosaur, dinosaur, and crocodile bones are recorded here for the first time in Upper Jurassic-Lower Cretaceous red beds in the Atacama region east of Copiapó, Chile. Trace fossils produced by vertebrate animals include the footprints of theropod dinosaurs and the depressions of sandstone laminae interpreted as burrows and foot impressions. The fossils occur in the 1500-meter-thick Quebrada Monardes Formation, which consists predominantly of the aeolian and alluvial deposits of a semi-arid terrestrial environment. Vertebrate fossils are very rare in Chile. Dinosaur bones and footprints have previously been recorded at only seven locations, and pterosaur remains at only one location. The newly discovered dinosaur bones are the oldest to be described in Chile.

Bell, C. M.; Suárez, M.

297

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.

298

"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

299

Total petroleum systems of the Bonaparte Gulf Basin area, Australia; Jurassic, Early Cretaceous-Mesozoic; Keyling, Hyland Bay-Permian; Milligans-Carboniferous, Permian  

USGS Publications Warehouse

The Bonaparte Gulf Basin Province (USGS #3910) of northern Australia contains three important hydrocarbon source-rock intervals. The oldest source-rock interval and associated reservoir rocks is the Milligans-Carboniferous, Permian petroleum system. This petroleum system is located at the southern end of Joseph Bonaparte Gulf and includes both onshore and offshore areas within a northwest to southeast trending Paleozoic rift that was initiated in the Devonian. The Milligans Formation is a Carboniferous marine shale that sources accumulations of both oil and gas in Carboniferous and Permian deltaic, marine shelf carbonate, and shallow to deep marine sandstones. The second petroleum system in the Paleozoic rift is the Keyling, Hyland Bay-Permian. Source rocks include Lower Permian Keyling Formation delta-plain coals and marginal marine shales combined with Upper Permian Hyland Bay Formation prodelta shales. These source-rock intervals provide gas and condensate for fluvial, deltaic, and shallow marine sandstone reservoirs primarily within several members of the Hyland Bay Formation. The Keyling, Hyland Bay-Permian petroleum system is located in the Joseph Bonaparte Gulf, north of the Milligans-Carboniferous, Permian petroleum system, and may extend northwest under the Vulcan graben sub-basin. The third and youngest petroleum system is the Jurassic, Early Cretaceous-Mesozoic system that is located seaward of Joseph Bonaparte Gulf on the Australian continental shelf, and trends southwest-northeast. Source-rock intervals in the Vulcan graben sub-basin include deltaic mudstones of the Middle Jurassic Plover Formation and organic-rich marine shales of the Upper Jurassic Vulcan Formation and Lower Cretaceous Echuca Shoals Formation. These intervals produce gas, oil, and condensate that accumulates in, shallow- to deep-marine sandstone reservoirs of the Challis and Vulcan Formations of Jurassic to Cretaceous age. Organic-rich, marginal marine claystones and coals of the Plover Formation (Lower to Upper Jurassic), combined with marine claystones of the Flamingo Group and Darwin Formation (Upper Jurassic to Lower Cretaceous) comprise the source rocks for the remaining area of the system. These claystones and coals source oil, gas, and condensate accumulations in reservoirs of continental to marine sandstones of the Plover Formation and Flamingo Group. Shales of the regionally distributed Lower Cretaceous Bathurst Island Group and intraformational shales act as seals for hydrocarbons trapped in anticlines and fault blocks, which are the major traps of the province. Production in the Bonaparte Gulf Basin Province began in 1986 using floating production facilities, and had been limited to three offshore fields located in the Vulcan graben sub-basin. Cumulative production from these fields totaled more than 124 million barrels of oil before the facilities were removed after production fell substantially in 1995. Production began in 1998 from three offshore wells in the Zone of Cooperation through floating production facilities. After forty years of exploration, a new infrastructure of pipelines and facilities are planned to tap already discovered offshore reserves and to support additional development.

Bishop, M.G.

1999-01-01

300

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

301

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

302

Diagenesis and fluid flow in the San Juan Basin, New Mexico - regional zonation in the mineralogy and stable isotope composition of clay minerals in sandstone.  

USGS Publications Warehouse

The Westwater Canyon Member of the Upper Jurassic Morrison Formation is a relatively homogeneous, hydrologically continuous 100-m-thick sequence of massive fluvial sandstone, bounded above and below by relatively heterogeneous, hydrologically discontinuous units and has served as a primary conduit for fluids within this stratigraphic interval. Patterns of mineral-fluid reactions suggest a basinwide hydrologic regime in which warm, evolved fluids migrated up-dip from the center of the basin under the influence of a regional hydraulic head. -from Authors

Whitney, G.; Northrop, H.R.

1987-01-01

303

A clean-burning biofuel as a response to adverse impacts of woodsmoke and coalsmoke on Navajo health  

SciTech Connect

Because over 60% of Navajo households are heated with woodfuel and coal, and indoor air pollution from woodsmoke and coalsmoke is problematic, most Navajos are probably at risk of respiratory and other smoke-induced illnesses. A previous study has shown that Navajo children living in homes heated by a wood/coal stove are nearly five times more likely to contract acute lower respiratory tract infections than children from homes that do not use those fuels. Stove and flue improvements to reduce leakage of smoke into the home would help. So would clean-burning solid fuels in replacement of woodfuel and coal. The authors describe a clean-burning fast-growing carbohydrate biofuel, prepared by sun-drying the roots of a wild southwestern gourd plant, Cucurbita foetidissima. They call it {open_quotes}rootfuel.{close_quotes} A test plot is growing during the 1994 season at the NMSU Agricultural Science Center on the Navajo Nation, near Farmington, New Mexico. Irrigation requirements are being measured. In the Fall, a preliminary needs assessment will be conducted to learn more about how fuel usage impacts Navajo health. The acceptability of rootfuel in selected homes will be tested during the upcoming heating season.

Shultz, E.B. Jr.; Bragg, W.G. [Enable International, Wheaton, IL (United States); Whittier, J. [NEOS Corporation, Lakewood, CO (United States)] [and others

1994-12-31

304

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

305

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.

306

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

307

Triassic/Jurassic faulting patterns of Conecuh Ridge, southwest Alabama  

SciTech Connect

Two major fault systems influenced Jurassic structure and deposition on the Conecuh Ridge, southwest Alabama. Identification and dating of these fault systems are based on seismic-stratigraphic interpretation of a 7-township grid in Monroe and Conecuh Counties. Relative time of faulting is determined by fault geometry and by formation isopachs and isochrons. Smackover and Norphlet Formations, both Late Jurassic in age, are mappable seismic reflectors and are thus reliable for seismicstratigraphic dating. The earlier of the 2 fault systems is a series of horsts and grabens that trends northeast-southwest and is Late Triassic to Early Jurassic in age. The system formed in response to tensional stress associated with the opening of the Atlantic Ocean. The resulting topography was a series of northeast-southwest-trending ridges. Upper Triassic Eagle Mills and Jurassic Werner Formations were deposited in the grabens. The later fault system is also a series of horsts and grabens trending perpendicular to the first. This system was caused by tensional stress related to a pulse in the opening of the Gulf of Mexico. Faulting began in Early Jurassic and continued into Late Jurassic, becoming progressively younger basinward. At the basin margin, faulting produced a very irregular shoreline. Submerged horst blocks became centers for shoaling or carbonate buildups. Today, these blocks are exploration targets in southwest Alabama.

Hutley, J.K.

1985-02-01

308

Surface energy characterization of sandstone rocks  

NASA Astrophysics Data System (ADS)

The fundamental forces of adhesion are responsible for the spreading of fluids such as crude oil/brine on the reservoir rock surface. These physico-chemical interactions determine the surface energetics of a reservoir and thus their wetting phenomena. Inverse Gas Chromatography (IGC) is introduced to characterize the surface energy of sandstones (Ottawa sand and Berea sandstone). The surface chemistry of the sandstone rocks is further elucidated using X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) techniques. The behavior of the polar and non-polar interaction forces was investigated at varying water coverage and at different temperatures. The results indicated that in general as the water coverage increased, the Lifshitz-van der Waals component of surface energy decreased to nearly that of the bulk water, while the acid-base component also showed a decreasing trend. The Lifshitz-van der Waals component of surface energy always decreased with increase in temperature, while the acid-base properties showed contrasting trends in line with changes in surface chemistry of the sandstones, due to the change in temperature. Finally, the wetting properties arising in reservoir sandstones were related to the surface chemistry of the reservoir fluids and their interactions with the reservoir rock surface.

Arsalan, Naveed; Palayangoda, Sujeewa S.; Burnett, Daniel J.; Buiting, Johannes J.; Nguyen, Quoc P.

2013-08-01

309

The Origin of the Jurassic Quiet Zone -new insights from Hawaiian Jurassic magnetic anomalies (Invited)  

NASA Astrophysics Data System (ADS)

Marine magnetic anomalies recorded in oceanic crust, have played a central role in documenting Earth's magnetic field history as compiled in the geomagnetic polarity timescale (GPTS). The oldest part of the marine record is the Jurassic Quiet Zone (JQZ) (pre-M29 chrons) which is known to be a period when field intensity was low, while reversal rate was high. The origin and character of the JQZ has been the subject of marine magnetic studies over past 20 years in the western Pacific where the oldest and arguably best preserved Jurassic magnetic anomalies create three Jurassic lineation sets (Japanese, Hawaiian, and Phoenix). The Japanese JQZ sequence was extensively investigated by an aeromagnetic and 2 deeptow magnetometer surveys, revealing (i) the presence of lineated anomalies older than M29; (ii) a GPTS record extending from M29 to M44 with a tie to ODP Hole 801C and (iii) remarkably fast reversals that decrease in intensity back in time until M38. Prior to M38 there is a low amplitude zone (LAZ) in anomalies lasting until M42, when both anomaly amplitude and a lineated character reappears around Hole 801C. Recently collected (2011) high quality seasurface marine magnetic anomaly data from the Hawaiian lineations show changes in magnetic anomaly shape and amplitude that are similar in to the Japanese lineations, suggesting that the anomalies record globally coherent geomagnetic field behavior for the Jurassic. Specifically, the strong similarity of anomaly patterns between the Japanese and Hawaiian sequences from M19 to M38 supports the remarkably dynamic geomagnetic field behavior of fast reversals and changing intensity, confirming a proposed record of the GPTS sequence for M29 to M38. While the LAZ in the Hawaiian sequence is not as clear as in the Japanese lineations, we believe we can correlate the earlier M42-M44 sequence between the two sets of lineations. The slower spreading rate in the Hawaiian lineations may contribute to this lack of resolution of the LAZ and result in a less clear recording of anomalies. We present models to investigate if this is simply a lack of spatial resolution or if there are indeed different processes active within the Hawaiian sequence such as seamount/plateau formation and crustal construction.

Tominaga, M.; Tivey, M.; Sager, W. W.

2013-12-01

310

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

311

Paleozoic to Jurassic terrane accretion along the northeastern margin of Tibet plateau  

NASA Astrophysics Data System (ADS)

The Tibet plateau is considered to have been constructed by a number of basement terranes accreted to the Eurasian margin during Paleozoic to Mesozoic times, and accretion is interpreted to have progressed southwards. The northern margin, exposed in Altyn and Qilian Mountains, is generally considered as an Lower Paleozoic orogen including previously subducted ultra-high successions (Yin and Harrison, 2000; Xiao et al., 2009). Previous tectonic models of the Qaidam block and adjacent mountain ranges at the northeastern margin of the Tibet plateau assumed a minor role of Indosinian tectonism in that region, and firm evidence was only reported from eastern Kunlun Mountains (e.g., Liu et al., 2005). Based on four sources of new data, we propose that the Indosinian tectonism was much more widespread in the northeastern Qaidam block and adjacent mountain ranges, Altyn and Qilian Mts., as believed before and we propose a new tectonic model. The new data sources comprise: (1) 40Ar/39Ar dating of detrital white mica of Jurassic to Pliocene sandstones from the north-eastern Qaidam basin fill; (2) interpretation of Ordovician, Devonian and Jurassic sedimentary successions, from which we interpret the Jurassic successions as intramontane molasse to the Indosinian orogen; (3) 40Ar/39Ar dating of detrital white mica in recent rivers from the southern Qilian Shan revealing possible basement sources in the Qilian Shan draining towards the Qaidam basin; and (4) structural study of basement rocks and subordinate 40Ar/39Ar mineral ages of metamorphic basement rocks. An Ordovician greywacke exposed in the eastern Qaidam basin (W of Delinghua) yields three 40Ar/39Ar age groups of detrital white mica: 900-922, 610-654 and 527-554 Ma. Furthermore, similar old age groups centering at ca. 670 and 1010 Ma are virtually widespread in recent rivers from Qilian Mountains and clearly demonstrate the presence of Panafrican and Grenvillian tectonic elements in the southern Qilian Mts. at the northeastern edge of the Tibetan plateau. This is consistent with scarce reports of U-Pb zircon and Sm-Nd ages from mainly oceanic tectonic elements. Scarce Panafrican ages were also reported from the North Altyn Mountains, too. These units are bordered by a Lower Proterozoic metamorphic and plutonic basement in the north, mainly exposed in the North Altyn Mts, Beishan and North China craton representing a continental microplate separating these units from the Paleozoic Altaids. Our preliminary study of detrital white mica from Eocene to Miocene successions of the northeastern Qaidam basin suggested that a basement with 250 ± 3 and 279 ± 3 Ma must be present in the southern Qilian Shan (Rieser et al., 2007). 40Ar/39Ar dating of detrital white mica from outlets of recent rivers draining into the Qaidam yield following age groups: 190-220 Ma, 240-263 Ma, 310-315 Ma, 400-440 Ma and some values at ca. 1010 Ma. The 190-240 Ma group shows a dominant but slightly younger age as found in our previous study from the Qaidam basin fill and indicate that metamorphic basement successions with late Triassic to earliest Jurassic cooling ages are part of the southern Qilian Shan. These new data gives evidence for the presence of Triassic to Jurassic metamorphic sectors in the southern Qilian Shan and that these units are bordered by a Jurassic basin. The lag time between cooling in the hinterland and deposition in Jurassic basin is low implying rapid exhumation in the hinterland. Based on all these data, we develop a new tectonic model of stepwise accretion of Gondwana-derived units to the northern Lower Proterozoic craton similar as Stampfli and Borel (2002) proposed for the more western Tethysides. Principal age steps of accretion include Late Ordovician-Silurian, Carboniferous and Late Permian-Triassic, the later step also resulting in the final accretion of these units to Eurasia. The Lower Jurassic siliciclastic deposits are thickening towards Qilian Mts. and are interpreted to represent molasse-type deposits to an Indosinian metamorphic element, which exhumed during early

Neubauer, Franz; Liu, Yongjiang; Genser, Johann; Ren, Shoumai

2010-05-01

312

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

313

Root grooves on sandstone bedrock, Ouachita Mountains  

NASA Astrophysics Data System (ADS)

This study presents findings demonstrating the existence of root grooves on siliceous sandstone. It is clear from biochemical studies that weathering in ecosystems with vigorous plant growth is more rapid than in non-vegetated areas, and previous studies of the interactions between tree roots and bedrock have demonstrated the importance of trees in breaking down bedrock through biophysical and biomechanical processes, including treethrow. However, the development of root grooves has rarely been reported on bedrock other than limestone or calcareous substrate. This poster will show the existence of tree root grooves on siliceous sandstone in the Ouachita Mountains, and will discuss the processes that have led to their genesis and development.

Turkington, A. T.

2010-12-01

314

Trace fossil assemblages in selected shelf sandstones  

E-print Network

TRACE FOSSIl. ASSEMBLAGES IN SELECTED SHELF SANDSTONES A Thesis by KATHLEEN ANN LOCKE Submitted to the Graduate Co11ege of Texas A&M University in partial fu1, i11ment of the requirement for the degree of MASTER Gl- SCIENCE August lg83... Medor 'ul. ', ect: Leo'. ogy TRACE FOSSIL ASSEMBLAGES IN SELECTED SHELF SANDSTONES A Thesis by KATHLEEN ANN LOCKE Approved as to style and content by: Robert R. Berg (Chairman of Committee) Robert . St on (Member) Rezneat M. Darnell (Member...

Locke, Kathleen Ann

2012-06-07

315

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

316

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

317

Processes controlling the composition of heavy mineral assemblages in sandstones  

Microsoft Academic Search

Sandstone compositions result from a complex interplay between provenance and factors that operate during the sedimentation cycle. Accurate identification and discrimination of provenance depends on isolating provenance-sensitive features, and avoiding parameters that are influenced by other factors. Heavy mineral analysis offers a high-resolution approach to determination of sandstone provenance, because of the diversity of mineral species found in sandstones and

Andrew C Morton; Claire R Hallsworth

1999-01-01

318

The Triassic-Jurassic boundary in eastern North America  

NASA Technical Reports Server (NTRS)

Rift basins of the Atlantic passive margin in eastern North America are filled with thousands of meters of continental rocks termed the Newark Supergroup which provide an unprecedented opportunity to examine the fine scale structure of the Triassic-Jurassic mass extinction in continental environments. Time control, vital to the understanding of the mechanisms behind mass extinctions, is provided by lake-level cycles apparently controlled by orbitally induced climate change allowing resolution at the less than 21,000 year level. Correlation with other provinces is provided by a developing high resolution magnetostratigraphy and palynologically-based biostratigraphy. A large number of at least local vertebrate and palynomorph extinctions are concentrated around the boundary with survivors constituting the earliest Jurassic assemblages, apparently without the introduction of new taxa. The palynofloral transition is marked by the dramatic elimination of a relatively high diversity Triassic pollen assemblage with the survivors making up a Jurassic assemblage of very low diversity overwhelmingly dominated by Corollina. Based principally on palynological correlations, the hypothesis that these continental taxonomic transitions were synchronous with the massive Triassic-Jurassic marine extinctions is strongly corroborated. An extremely rapid, perhaps catastrophic, taxonomic turnover at the Triassic-Jurassic boundary, synchronous in continental and marine realms is hypothesized and discussed.

Olsen, P. E.; Comet, B.

1988-01-01

319

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

320

Developments in Petroleum Science, 29 compressibilityof sandstones  

E-print Network

#12;Developments in Petroleum Science, 29 compressibilityof sandstones #12;DEVELOPMENTS IN PETROLEUM SCIENCE Advisory Editor: G.V.Chilingarian Volumes 1,3,4,7and 13 are out of print. 2. W.H.FERTL 5. and S. KUMAR G.V. CHILINGARIAN, J.O. ROBERTSON Jr. and S. KUMAR SURFACE OPERATIONS IN PETROLEUM

Santos, Juan

321

Seismic characteristics of sandstone hydrocarbon reservoirs  

Microsoft Academic Search

In seismic terms, three distinct zones of sandstone reservoirs can be defined (Neidell, SEG Distinguished Lecture, 1986): Zone I sands with low acoustic impedance when wet and, in contrast with contemporary aged shales, gas presence is signaled with Bright Spots; Zone III sands have impedance values higher than associated shales (The Compacted Zone) and indicate gas presence with subtle amplitude

N. S. Neidell; W. C. Lefler; W. R. Landwer; M. Smith

1993-01-01

322

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

323

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

324

Fire Clay coal and sandstone washouts  

SciTech Connect

The Fire Clay coal bed has been studied in a portion of southeastern Kentucky. This seam is easily recognizable by a distinctive flint clay parting. Mine maps, field descriptions, and laboratory investigations were used to investigate this coal bed. Several elongate sandstone bodies cut the seam in the study area. These sandstone bodies are subparallel roughly east-west, and are typically 10[sup 1] to 10[sup 2] m wide, and 10[sup 2] m to tens of kilometers long. These sandstone washouts occur in areas overlain by a larger channel sandstone, which usually is found associated with the thickest areas of the coal seam. In south-central Perry County, a cross section of one washout area was well exposed. North of the washout, a 4 to 7 cm thick cannel coal was present at the base of the sequence. The coal on the north side of the cutout gradually thins from 2 m to 1.5 m away from the washout. On the south side of the washout, the coal thins abruptly from over 1.5 m to 1.25 m within 30 m of the channel. An island of slumped and slickensided coal is present within the washout region. Postdepositional differential compaction of the peat is inferred to be the control on placement of the channel system. The areas of thickest peat compacted the most, creating topographic lows through which the stream moved. The regions of thick coal were probably the result of several controlling factors. Predepositional differential compaction and erosion may have produced relief which influenced peat development. Lithologic and geochemical continuity across the channel is good, supporting postdepositional emplacement of the sandstone bodies.

Andrews, W.M. Jr.; Hower, J.C. (Univ. of Kentucky, Lexington, KY (United States). Center for Applied Energy Research)

1992-01-01

325

Harvestmen (Arachnida: Opiliones) from the Middle Jurassic of China  

NASA Astrophysics Data System (ADS)

Harvestmen (Arachnida: Opiliones) are familiar animals in most terrestrial habitats but are rare as fossils, with only a handful of species known from each of the Palaeozoic, Mesozoic, and Cenozoic eras. Fossil harvestmen from Middle Jurassic (ca. 165 Ma) strata of Daohugou, Inner Mongolia, China, are described as Mesobunus martensi gen. et sp. nov. and Daohugopilio sheari gen. et sp. nov.; the two genera differ primarily in the relative length of their legs and details of the pedipalps. Jurassic arachnids are extremely rare and these fossils represent the first Jurassic, and only the fourth Mesozoic, record of Opiliones. These remarkably well-preserved and modern-looking fossils are assigned to the Eupnoi, whereby M. martensi demonstrably belongs in Sclerosomatidae. It thus represents the oldest record of a modern harvestman family and implies a high degree of evolutionary stasis among one of the most widespread and abundant groups of long-legged, round-bodied harvestmen.

Huang, Diying; Selden, Paul A.; Dunlop, Jason A.

2009-08-01

326

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.

327

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

328

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

Code of Federal Regulations, 2013 CFR

...What notifications are required that tribal laws apply to grazing permits on the Navajo...LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.102 What notifications are required that tribal laws apply to grazing permits on the...

2013-04-01

329

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

Code of Federal Regulations, 2011 CFR

...What notifications are required that tribal laws apply to grazing permits on the Navajo...LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.102 What notifications are required that tribal laws apply to grazing permits on the...

2011-04-01

330

Bayesian models for elevated disease risk due to exposure to uranium mine and mill waste on the Navajo Nation  

E-print Network

ForReview Only Bayesian models for elevated disease risk due to exposure to uranium mine and mill of Pharmacy, Community Environmental Health Program Keywords: abandoned uranium mines, conditionally specified to ex- posure to uranium mine and mill waste on the Navajo Nation Glenn A. Stark University of New

Huerta, Gabriel

331

A Study of Navajo Perceptions of the Impact of Environmental Changes Relating to Energy Resource Development. Final Report.  

ERIC Educational Resources Information Center

Ethnographic interview methods were utilized to determine the social costs of energy development (i.e. uranium mining) and the mitigation of these costs. Determination was made from the viewpoint of the Navajos in the Burnhams Chapter (a geopolitical unit) in Western New Mexico; they anticipated four major costs (losses) to their present way of…

Schoepfle, G. Mark; And Others

332

Increasing Vulnerability to Drought and Climate Change on the Navajo Nation, southwestern United States  

NASA Astrophysics Data System (ADS)

The Navajo Nation of Arizona, New Mexico, and Utah, is an ecologically sensitive semi-arid to arid area where rapid growth of one of the largest population of Native Americans is outstripping the capacity of the land to sustain them. Recent drought conditions, combined with increasing temperatures, are significantly altering the habitability of a region already characterized by harsh living conditions. In addition to altered landscape conditions due to climatic change, drought, and varying land use practices over the last 200 years, the Navajo people have been affected by land use policies and harsh economic conditions that weaken their cultural fabric. Increasing aridity combined with drought threaten the very existence of Navajo culture and the survival of traditional Navajo communities. People presently living on these Native lands are unique in American society as their traditional lifestyle requires intimate knowledge of the ecosystem, knowledge that has been passed on for generations through oral traditions. We present data from the lifelong observations of 73 Native American elders that provide a record of the changes in plants and animals, water availability, weather, and sand or dust storms. This information is used to complement the scant long-term meteorological records and historical documentation for the region to further refine our understanding of the historical trends and local impacts of climate change and drought. Among the most cited changes is a long-term decrease in the amount of annual snowfall over the past century, a transition from wet conditions to dry conditions in the 1940s, and a decline in surface water features. The lack of available water, in addition to changing socioeconomic conditions, was mentioned as a leading cause for the decline in the ability to grow corn and other crops. Other noted changes include the disappearance of springs, and of plant and animal populations (particularly medicinal plants, cottonwood trees, beavers, and eagles). Changes in the frequency of wind, sand and dust storms (more frequent in the 1950s and increasing in the 1990s) were also observed. Important information that cannot be easily gleaned from meteorological and stream flow records are also recorded in our consultations. For example, they include observations of soil moisture and the description of disappearing migratory birds that rely on water sources. Local monitoring of soil moisture conditions today indicates that a rapid decline occurs in the Springtime. The fact that soil moisture was noted in the past to persist through the spring dry season, until the late summer monsoon season has profound implications for impacts to ecosystem viability that may have already occurred with climate change and drought. In addition, these changes in soil moisture also help us understand the mechanisms contributing to current drought severity. We conclude that a long-term drying trend and decreasing snowpack, superimposed on regional drought cycles, will magnify the cultural and literal erosion and desertification of the Navajo Nation and leave its people increasingly vulnerable to climate extremes.

Hiza, M. M.; Kelley, K. B.; Francis, H.

2011-12-01

333

Occurrence of sauropod dinosaur tracks in the Upper Jurassic of Chile (redescription of Iguanodonichnus frenki)  

E-print Network

Occurrence of sauropod dinosaur tracks in the Upper Jurassic of Chile (redescription studied Upper Jurassic dinosaur unit in South America, the Ban~os del Flaco Formation, Chile. Keywords: Chile; Dinosaur footprints; Parabrontopodus; Sauropod; Upper Jurassic Resu´men En el presente

Benton, Michael

334

Strategies for assessing Early{Middle (Pliensbachian{Aalenian) Jurassic cyclochronologies  

Microsoft Academic Search

There are a number of fundamental problems in assessing the astronomically forced cyclostratigraphy of the Jurassic Period. First, Jurassic geochronology is not well constrained, due to a general scarcity of radiometric dates, inferior precision of the existing ones, and large inaccuracies in stratigraphic constraints. These problems are particularly troublesome in the Early to Middle Jurassic cyclic carbonates of the Colle

J. P ark

1999-01-01

335

Middle and upper jurassic depositional environments at outer shelf and slope of Baltimore Canyon Trough  

Microsoft Academic Search

New CDP data acquired in the Baltimore Canyon Trough during project LASE made it possible to map a continuous Jurassic sedimentary sequence from the continental margin to the abyssal plain without interruption by basement structures. Intense carbonate sedimentation is inferred at the outer shelf during the Middle and Late Jurassic. Carbonate sedimentation probably started during the Middle Jurassic with a

L. A. Gamboa; P. L. Stoffa; M. Truchan

1985-01-01

336

Geological model of the Jurassic section in the State of Kuwait  

SciTech Connect

Until the end of the seventies, the knowledge of Jurassic Geology in the State of Kuwait was very limited, since only one deep well was drilled and bottomed in the Triassic sediments. Few scattered wells partially penetrated the Jurassic sequence. During the eighties, appreciable number of wells were drilled through the Jurassic, and added a remarkable volume of information. consequently it was necessary to analyze the new data, in order to try to construct a geological model for the Jurassic in the State of Kuwait. This paper includes a number of isopach maps explaining the Jurassic depositional basin which also helps in trying to explain the Jurassic basin in the Arabian Gulf basin. Structural evolution of the Jurassic sequence indicated an inversion of relief when compared with the Cretaceous sequence. In fact, the main Cretaceous arches were sites of sedimentation troughs during the Jurassic period. This fact marks a revolution in the concepts for the Jurassic oil exploration. One of the very effective methods of the definition of the Jurassic structures is the isopaching of the Gotnia Formation. Najmah, Sargelu and Marrat Formations include the main Jurassic reservoirs which were detected as a result of the exploration activities during the eighties. Selective stratigraphic and structural cross sections have been prepared to demonstrate and explain the nature of the Jurassic sediments.

Yousif, S.; Nouman, G.

1995-11-01

337

Constraints on Upper Jurassic palaeogeography in the Ula Gyda trend  

SciTech Connect

BP Norway`s semi-regional 3D database in the Central Trough covers an area of nearly 3000 sq.km. around BP Norway`s two producing fields, Ula and Gyda, and includes strategic acreage within tie-back distance to the fields. Prospectivity in the Ula Gyda trend involves complex salt influenced structures and localized Upper Jurassic depositional systems. The objective of this paper is to demonstrate how the understanding of the semi-regional structures and salt tectonics helped constrain the interpretation of the Upper Jurassic palaeogeography. The control of basement structures (Permian) on cover structures (Upper Jurassic/Base Cretaceous) through Zechstein Salt was interpreted using the 3D semi-regional dataset. Analogue sandbox experiments from the Austin Geodynamics Laboratory provide support for the complex structures which were interpreted on the 3D seismic data. Sandbox models mimic the interpreted monoclinal drape of the Triassic and Jurassic section over the critical basin bounding fault in the Base Zechstein. Structural cells can be identified with the help of the salt isochore. The understanding of the relationship between structural development and salt distribution was a major control on the interpretation. This interpretation coupled with the Upper Jurassic reservoir distribution from well data provided the primary evidence for the gross depositional environment maps which were used in prospect evaluation in the area. 3D visualization and shaded relief displays of the interpreted horizons and isochores played a significant part in developing an understanding of the interplay between the deeper structures and the likely Upper Jurassic palaeogeography and depocentres.

Mundal, I.; Milton, N.; Robinson, N. [BP Norge, Stavanger (Norway)

1995-08-01

338

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

339

Low intensity of the geomagnetic field in early Jurassic time  

USGS Publications Warehouse

From a large collection of Jurassic continental tholeiites cropping out in Europe and Africa, we selected 90 samples for paleointensity determinations. Twenty-eight well-clustered paleointensity estimates were obtained from two European dikes that were emplaced during Early Jurassic time: the Kerforne dike at Brenterc'h in Brittany (northwestern France) and the Messejana dike on the Iberian Peninsula (Spain and Portugal). Virtual dipole moments calculated from both magmatic units are similar and only about one-third of present-day values. -from Authors

Perrin, M.; Prevot, M.; Mankinen, E.A.

1991-01-01

340

The second Jurassic dinosaur rush and the dawn of dinomania.  

PubMed

During the second Jurassic dinosaur rush museum paleontologists raced to display the world's first mounted sauropod dinosaur. The American Museum of Natural History triumphed in 1905 when its Brontosaurus debuted before an admiring crowd of wealthy New Yorkers. The Carnegie Museum of Natural History in Pittsburgh, the Field Columbian Museum in Chicago and other institutions were quick to follow with their own sauropod displays. Thereafter, dinomania spread far and wide, and big, showpiece dinosaurs became a museum staple. This brief but intensely competitive period of acquisitiveness fostered important Jurassic dinosaur revisions and crucial innovations in paleontological field and lab techniques. PMID:20667597

Brinkman, Paul D

2010-09-01

341

Progressive evolution of deformation band populations during Laramide fault-propagation folding: Navajo Sandstone, San Rafael monocline, Utah, U.S.A.  

NASA Astrophysics Data System (ADS)

Monoclinal fault propagation folds are a common type of structure in orogenic foreland settings, particularly on the Colorado Plateau. We have studied a portion of the San Rafael monocline, Utah, assumed to have formed through pure thrust- or reverse-slip (blind) fault movement, and mapped a particular sequence of subseismic cataclastic deformation structures (deformation bands) that can be related in terms of geometry, density and orientation to the dip of the forelimb or fold interlimb angle. In simple terms, deformation bands parallel to bedding are the first structures to form, increasing exponentially in number as the forelimb gets steeper. At about 30° rotation of the forelimb, bands forming ladder structures start to cross-cut bedding, consolidating themselves into a well-defined and regularly spaced network of deformation band zones that rotate with the layering during further deformation. In summary, we demonstrate a close relationship between limb dip and deformation band density that can be used to predict the distribution and orientation of such subseismic structures in subsurface reservoirs of similar type. Furthermore, given the fact that these cataclastic deformation bands compartmentalize fluid flow, this relationship can be used to predict or model fluid flow across and along comparable fault-propagation folds.

Zuluaga, Luisa F.; Fossen, Haakon; Rotevatn, Atle

2014-11-01

342

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

343

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

344

Recognition of Jurassic transport of rocks of the Roberts Mountains allochthon: Evidence from the Sonoma Range, north-central Nevada  

Microsoft Academic Search

The Sonoma Range of north-central Nevada exposes lower Paleozoic rocks of the Roberts Mountains allochthon that were thrust from east to west over Upper Triassic shelf strata in Jurassic time. Also present are Roberts Mountains allochthon rocks that were autochthonous in the Jurassic. Structural analysis of Jurassic allochthonous vs. Jurassic autochthonous rocks of the Harmony Formation indicates that both packages

Stephen D. Stahl

1989-01-01

345

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

346

Reconstruction of the Jurassic Conifer Sewardiodendron laxum (Taxodiaceae)  

Microsoft Academic Search

Compressed seed cones and pollen cones of Sewardiodendron laxumare described from the Middle Jurassic of Yima, Henan, central China. They are either organically attached to or associated with leafy shoots. Seed cones are terminally borne. Each cone is ovate to elongated, up to 6.5 cm long and 3.5 cm wide, and consists of a stout axis and numerous helically arranged

Xuanli Yao; Zhiyan Zhou; Bole Zhang

1998-01-01

347

CRANIAL ANATOMY, TAXONOMIC IMPLICATIONS AND PALAEOPATHOLOGY OF AN UPPER JURASSIC  

E-print Network

CRANIAL ANATOMY, TAXONOMIC IMPLICATIONS AND PALAEOPATHOLOGY OF AN UPPER JURASSIC PLIOSAUR (REPTILIA find. The specimen shows most of the cranial and mandibular anatomy, as well as a series is probably female. The large size of the animal, the extent of sutural fusion and the pathologies suggest

Benton, Michael

348

Let the Volgian stage stay in the Jurassic  

Microsoft Academic Search

In 1996 the Volgian Stage was divided into the Jurassic and Cretaceous units, removed from the Geological Time Scale, and substituted by the Tithonian Stage according to the guidelines of the Interdepartmental Stratigraphic Committee of the Russian Federation (ISC RF). Consequently, the Upper Volgian Substage including three zones (five subzones) was placed into the Berriasian Stage (the Cretaceous) proceeding from

V. A. Zakharov; M. A. Rogov

2008-01-01

349

Stratigraphy of the Jurassic system in northern Egypt  

SciTech Connect

A regional synthesis is presented of the stratigraphy of Jurassic strata in Egypt north of 30/degree/N, based on the study of about 80 wells and outcrops from northeastern Egypt. Almost all fossil groups have been investigated for biostratigraphic control. Published work on ammonite faunas from Gebel el Maghara (north Sinai) is integrated with extensive original work on palynofloras (and, to a lesser extent, ostracod/foraminiferal faunas) recovered from marine rocks in the subsurface. The recovery of rich dinocyst assemblages enables the recognition of a ten-fold zonation scheme, largely within the Middle-Late Jurassic sedimentary package. The upper limit of this package is marked by the Cimmerian erosional event; strata younger than Oxfordian are rarely preserved. Only east of 30/degree/E is significant sedimentation known to have occurred immediately prior to the major early Bajocian transgressive event. Thereafter mean sea level rose steadily. The Lower Triassic-Lower Jurassic sedimentary package is poorly understood, largely the result of scanty and ambiguous stratigraphic evidence. However, regional correlations suggest that only very thin earliest Jurassic (Hettangian ) clastic deposition succeeded a sequence of Upper Triassic carbonates and evaporites (Wadi en Natrun Formation) in the north. Arising from these studies is a standard lithostratigraphical scheme. The upper sedimentary package, the Gebel el Maghara Group, comprises three formations (Masajid, Khatatba, and Inmar) and seven members; new units are defined and old units redefined.

Keeley, M.L.; Shaw, D.; Forbes, G.A.

1988-08-01

350

Jurassic epithermal Au–Ag deposits of Patagonia, Argentina  

Microsoft Academic Search

Important precious metal deposits have been discovered during the last 10 years in the Deseado Massif region of Patagonia, Argentina. This region is a plateau consisting of Middle to Upper Jurassic volcanic rocks that host fracture-controlled epithermal Au–Ag mineralization. These mineral deposits represent low sulfidation type hydrothermal systems and formed following the main period of volcanism, probably during the Late

I. B Schalamuk; M Zubia; A Genini; R. R Fernandez

1997-01-01

351

The cranial anatomy of the Early Jurassic turtle Kayentachelys aprix  

Microsoft Academic Search

The fossil turtle Kayentachelys aprix is known from Early Jurassic sediments of the Kayenta Formation, Arizona, USA. The detailed description of this taxon's cranium offered in this paper demonstrates that this turtle presents a mixture of primitive and derived character states. Among others, the presence of an interpterygoid vacuity, a basipterygoid process, a prootic that is exposed in ventral view,

JULIANA STERLI; WALTER G. JOYCE

352

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

353

Comparison of geology of Jurassic Norphlet Mary Ann field, Mobile Bay, Alabama, to onshore regional Norphlet trends  

SciTech Connect

The geology of the Mary Ann field is better understood in light of regional studies, which help to establish a depositional model in terms of both facies and thickness variations. These studies also illustrate major differences between onshore and offshore Norphlet deposits concerning topics such as diagenesis, hydrocarbon trapping, and migration. The Jurassic Norphlet sandstone was deposited in an arid basin extending from east Texas to Florida by a fluvial-eolian depositional system, prior to the transgression of the Smackover Formation. Until discovery of the Mary Ann field in 1979, Norphlet production was restricted to onshore areas, mostly along the Pickens-Pollard fault system in Mississippi, Alabama, and Florida. The Mary Ann field is a Norphlet dry-gas accumulation, and was the first offshore field in the Gulf of Mexico to establish economic reserves in the Jurassic. The field is located in Mobile Bay, approximately 25 mi (40 km) south of Mobile, Alabama. Formed by a deep-seated (more than 20,000 ft or 6096 m) faulted salt pillow, Mary Ann field produces from a series of stacked eolian dune sands situated near the Norphlet paleocoastline. Five lithofacies have been recognized in cores from the Mobil 76 No. 2 well. Each lithofacies has a distinct reservoir quality. Optimum reservoir faces are the dune and sheet sands. Nonreservoir facies are interdune (wet and dry), marine reworked, and evaporitic sands. Following deposition, these sediments have undergone varying amounts of diagenesis. Early cementation of well-sorted sands supported the pore system during compaction. However, late cementation by chlorite, silica, and alteration of liquid hydrocarbons to an asphaltic residue have completely occluded the pore system in parts of the reservoir.

Marzono, M.; Pense, G.; Andronaco, P.

1988-09-01

354

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

355

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)

1996-12-31

356

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.

Erin Klauk

357

Vegetation, substrate, and eolian sediment transport at Teesto Wash, Navajo Nation, 2009-2012  

USGS Publications Warehouse

On the Navajo Nation, southwestern United States, warming temperatures and recent drought have increased eolian (windblown) sediment mobility such that large, migrating sand dunes affect grazing lands, housing, and road access. We present an assessment of seasonal variations in sand transport, mobility, and ground cover (vegetation and substrate) within a 0.2-km2 study area near Teesto Wash, southern Navajo Nation, as part of a multiyear study measuring the effects of drought on landscape stability. Sand mobility in the study area decreased substantially as one year (2010) with near-normal monsoon rainfall somewhat abated a decade-long drought, temporarily doubling vegetation cover. The invasive annual plant Russian thistle (Salsola sp.), in particular, thrived after the monsoon rains of 2010. Vegetation that grew during that year with adequate rain died off rapidly during drier conditions in 2011 and 2012, and the proportion of bare, open sand area increased steadily after summer 2010. We infer that isolated seasonal increases in rainfall will not improve landscape stability in the long term because sustained increase in perennial plants, which are more effective than annual plants at stabilizing sand against wind erosion, requires multiple consecutive seasons of adequate rain. On the basis of climate projections, a warmer, drier climate and potentially enhanced sediment supply from ephemeral washes may further increase eolian sediment transport and dune activity, worsening the present challenges to people living in this region. Connections between climate, vegetation cover, and eolian sediment erodibility in this region also are highly relevant for studies in other regions worldwide with similar environmental characteristics.

Draut, Amy E.; Redsteer, Margaret Hiza; Amoroso, Lee

2012-01-01

358

Samples from the Jurassic ocean crust beneath Gran Canaria, La Palma and Lanzarote (Canary Islands)  

NASA Astrophysics Data System (ADS)

Gabbro and minor metabasalt fragments of MORB composition were found on three of the seven Canary Islands. On Gran Canaria, they occur as metamorphosed (greenschist facies) metabasalt and metagabbro clasts in Miocene fanglomerates and sandstones overlying the shield basalts. On Lanzarote and La Palma, MORB gabbros occur as xenoliths in Pleistocene and historic basanite scoria cones and lava flows. The MORB xenoliths are interpreted as fragments of layers 2 and 3 of the underlying Mesozoic oceanic crust, based on mineral compositions (An-rich plagioclase, Ti- and Al-poor clinopyroxene, ± orthopyroxene ± olivine), depleted major and trace element signatures, and Jurassic ages (ca. 180 Ma) determined on single primary plagioclase and secondary amphibole crystals using the 40Ar/ 39Ar laser technique. The Lanzarote gabbros are very mafic (mg# 87 to 89 in clinopyroxene), moderately deformed, and highly depleted. Gran Canaria gabbros are more evolved (mg# 69 to 83 in clinopyroxene) and texturally mostly isotropic. La Palma MORB gabbros have a range of compositions (mg# 68 to 83 in clinopyroxene), some rocks being strongly metasomatized by interaction with basanite magma. The occurrence of MORB fragments on Lanzarote provides definite evidence that oceanic crust beneath the Canary Island archipelago continues at least as far east as the eastern Canary Islands. We postulate that MORB gabbros on Lanzarote which are commonly associated with peridotite xenoliths, represent the base of oceanic layer 3 where gabbros and peridotites were possibly tectonically interleaved. Such tectonic mixing would explain the enigmatic seismic velocities in this area. Gabbro xenoliths from La Palma were derived from within layer 3, probably from wall rock close to magma reservoirs emplaced during the Pleistocene/Holocene growth of La Palma. The Gran Canaria xenoliths are interpreted to represent the metamorphosed layer 2 and upper layer 3. The abundance of lower crustal xenoliths emphasizes the importance of the lower crust and crust-mantle boundary zone as a major level of magma accumulation.

Schmincke, Hans-Ulrich; Klügel, Andreas; Hansteen, Thor H.; Hoernle, Kaj; van den Bogaard, Paul

1998-11-01

359

Sedimentology of the Upper Triassic-Lower Jurassic (?) Mosolotsane Formation (Karoo Supergroup), Kalahari Karoo Basin, Botswana  

NASA Astrophysics Data System (ADS)

The Mosolotsane Formation (Lebung Group, Karoo Supergroup) in the Kalahari Karoo Basin of Botswana is a scantly exposed, terrestrial red bed succession which is lithologically correlated with the Late Triassic to Early Jurassic Molteno and Elliot Formations (Karoo Supergroup) in South Africa. New evidence derived from field observations and borehole data via sedimentary facies analysis allowed the assessment of the facies characteristics, distribution and thickness variation as well as palaeo-current directions and sediment composition, and resulted in the palaeo-environmental reconstruction of this poorly known unit. Our results show that the Mosolotsane Formation was deposited in a relatively low-sinuosity meandering river system that drained in a possibly semi-arid environment. Sandstone petrography revealed mainly quartz-rich arenites that were derived from a continental block provenance dominated by metamorphic and/or igneous rocks. Palaeo-flow measurements indicate reasonably strong, unidirectional current patterns with mean flow directions from southeast and east-southeast to northwest and west-northwest. Regional thickness and facies distributions as well as palaeo-drainage indicators suggest that the main depocenter of the Mosolotsane Formation was in the central part of the Kalahari Karoo Basin. Separated from this main depocenter by a west-northwest - east-southeast trending elevated area, an additional depocenter was situated in the north-northeast part of the basin and probably formed part of the Mid-Zambezi Karoo Basin. In addition, data also suggests that further northeast-southwest trending uplands probably existed in the northwest and east, the latter separating the main Kalahari Karoo depocenter from the Tuli Basin.

Bordy, Emese M.; Segwabe, Tebogo; Makuke, Bonno

2010-08-01

360

A new pterosaur tracksite from the jurassic summerville formation, near Ferron, Utah  

USGS Publications Warehouse

Pterosaur tracks (cf. Pteraichnus) from the Summerville Formation of the Ferron area of central Utah add to the growing record of Pteraichnus tracksites in the Late Jurassic Summerville Formation and time-equivalent, or near time-equivalent, deposits. The site is typical in revealing high pterosaur track densities, but low ichnodiversity suggesting congregations or "flocks" of many individuals. Footprint length varies from 2.0 to 7.0 cms. The ratio of well-preserved pes:manus tracks is about 1:3.4. This reflects a bias in favor of preservation of manus tracks due to the greater weight-bearing role of the front limbs, as noted in other pterosaur track assemblages. The sample also reveals a number of well-preserved trackways including one suggestive of pes-only progression that might be associated with take off or landing, and another that shows pronounced lengthening of stride indicating acceleration. One well-preserved medium-sized theropod trackway (Therangospodus) and other larger theropod track casts (cf. Megalosauripus) are associated with what otherwise appears to be a nearly monospecific pterosaur track assemblage. However, traces of a fifth pes digit suggest some tracks are of rhamphorynchoid rather than pterodactyloid origin, as usually inferred for Pteraichnus. The tracks occur at several horizons in a thin stratigraphic interval of ripple marked sandstones and siltstones. Overall the assemblage is similar to others found in the same time interval in the Western Interior from central and eastern Utah through central and southern Wyoming, Colorado, northeastern Arizona, and western Oklahoma. This vast "Pteraichnus ichnofacies" with associated saurischian tracks, remains the only ichnological evidence of pre-Cretaceous pterosaurs in North America and sheds important light on the vertebrate ecology of the Summerville Formation and contiguous deposits. ?? Taylor and Francis Inc.

Mickelson, D.L.; Lockley, M.G.; Bishop, J.; Kirkland, J.

2003-01-01

361

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

362

New insights into regional tectonics of the Indochina Peninsula inferred from Lower-Middle Jurassic paleomagnetic data of the Sibumasu Terrane  

NASA Astrophysics Data System (ADS)

The post-Jurassic occurrence of differential tectonic rotation between the Indochina and South Sundaland blocks remains an issue to be properly investigated. New paleomagnetic study is used here to find the role of Sibumasu Terrane in this rotation, which is located between a clockwise rotated Indochina Block and a counter-clockwise rotated South Sundaland Block. For this purpose, lower to middle Jurassic red sandstones of the Umphang Group in the Sibumasu Terrane were sampled at 21 sites in the Ratchaburi area (13.6°E, 99.6°E), Thailand. Stepwise thermal demagnetization by 680 °C unblocked a pre-folding characteristic remanent magnetization. A mean direction of this component at 100% unfolding is Ds = 348.5°, Is = 24.7°, ?95 = 10.5°, k = 10.7, N = 20, corresponding to an Early-Middle Jurassic pole of ? = 78.6°N, ? = 10.6°E (A95 = 9.3). Comparison of this direction with those reported from other localities of the Umphang Group (Kalaw, Mae Sot and North Trang Syncline localities) reveal variable declinations (between 348.5° and 44.7°) for the Sibumasu Terrane. We ascribe this variation to differential tectonic deformation in the Sibumasu Terrane, as reflected from sinusoidal shaped structural features in the study area. The presence of such features in the granitic rocks indicates the occurrences of deformational activities after their intrusion, which took place in the period between 130 Ma and 51 Ma. The Sibumasu Terrane behaved as an independent fragment at a time when Indochina was undergoing a clockwise rotation and southward displacement, as a result of extrusion tectonics after the gigantic India-Asia collision. Taking into consideration a westerly deflected declination (D = 342.8°) from the West Trang area in Peninsular Thailand, a counterclockwise rotation of 15° is estimated for the Sibumasu Terrane, as a result of continuous northward indentation of the Australian Plate into South Sundaland Block.

Fujiwara, Katsuya P.; Zaman, Haider; Surinkum, Adichat; Chaiwong, Nikhom; Fujihara, Makoto; Ahn, Hyeon-Seon; Otofuji, Yo-ichiro

2014-11-01

363

Factors controlling localization of uranium deposits in the Dakota Sandstone, Gallup and Ambrosia Lake mining districts, McKinley County, New Mexico  

USGS Publications Warehouse

Geologic studies were made at all of the uranium mines and prospects in the Dakota Sandstone of Early(?) and Late Cretaceous age in the Gallup mining district, McKinley County, New Mexico. Dakota mines in the adjacent Ambrosia Lake mining district were visited briefly for comparative purposes. Mines in the eastern part of the Gallup district, and in the Ambrosia Lake district, are on the Chaco slope of the southern San Juan Basin in strata which dip gently northward toward the central part of the basin. Mines in the western part of the Gallup district are along the Gallup hogback (Nutria monocline) in strata which dip steeply westward into the Gallup sag. Geologic factors which controlled formation of the uranium deposits in the Dakota Sandstone are: (1) a source of uranium, believed to be uranium deposits of the underlying Morrison Formation of Late Jurassic age; (2) the accessibility to the Dakota of uranium-bearing solutions from the Morrison; (3) the presence in the Dakota of permeable sandstone beds overlain by impermeable carbonaceous shale beds; and (4) the occurrence within the permeable Dakota sandstone beds of carbonaceous reducing material as bedding-plane laminae, or as pockets of carbonaceous trash. Most of the Dakota uranium deposits are found in the lower part of the formation in marginal-marine distributary-channel sandstones which were deposited in the backshore environment. However, the Hogback no. 4 (Hyde) Mine (Gallup district) occurs in sandy paludal shale of the backshore environment, and another deposit, the Silver Spur (Ambrosia Lake district), is found in what is interpreted to be a massive beach or barrier-bar sandstone of the foreshore environment in the upper part of the Dakota. The sedimentary depositional environment most favorable for the accumulation of uranium is that of backshore areas lateral to main distributary channels, where levee, splay, and some distributary-channel sandstones intertongue with gray carbonaceous shales and siltstones of the well-drained swamp environment. Deposits of black carbonaceous shale which were formed in the poorly drained swamp deposits of the interfluve area are not favorable host rocks for uranium. The depositional energy levels of the various environments in which the sandstone and shale beds of the Dakota were deposited govern the relative favorability of the strata as uranium host rocks. In the report area, uranium usually occurs in carbonaceous sandstone deposited under low- to medium-energy fluvial conditions within distributary channels. A prerequisite, however, is that such sandstone be overlain by impermeable carbonaceous shale beds. Low- to medium-energy fluvial conditions result in the deposition of sandstone beds having detrital carbonaceous material distributed in laminae or in trash pockets on bedding planes. The carbonaceous laminae and trash pockets provide the necessary reductant to cause precipitation of uranium from solution. High-energy fluvial conditions result in the deposition of sandstones having little or no carbonaceous material included to provide a reductant. Very low energy swampy conditions result in carbonaceous shale deposits, which are generally barren of uranium because of their relative impermeability to migrating uranium-bearing solutions.

Pierson, Charles Thomas; Green, Morris W.

1977-01-01

364

Geochemistry of vanadium in an epigenetic, sandstone-hosted vanadium- uranium deposit, Henry Basin, Utah  

USGS Publications Warehouse

The epigenetic Tony M vanadium-uranium orebody in south-central Utah is hosted in fluvial sandstones of the Morrison Formation (Upper Jurassic). Measurements of the relative amounts of V+3 and V +4 in ore minerals show that V+3 is more abundant. Thermodynamic calculations show that vanadium was more likely transported to the site of mineralization as V+4. The ore formed as V+4 was reduced by hydrogen sulfide, followed by hydrolysis and precipitation of V+3 in oxide minerals or chlorite. Uranium was transported as uranyl ion (U+6), or some complex thereof, and reduced by hydrogen sulfide, forming coffinite. Detrital organic matter in the rocks served as the carbon source for sulfate-reducing bacteria. Vanadium most likely was derived from the dissolution of iron-titanium oxides. Uranium probably was derived from the overlying Brushy Basin Member of the Morrison Formation. Previous studies have shown that the ore formed at the density-stratified interface between a basinal brine and dilute meteoric water. The mineralization processes described above occurred within the mixing zone between these two fluids. -from Authors

Wanty, R.B.; Goldhaber, M.B.; Northrop, H.R.

1990-01-01

365

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

366

Development and pilot evaluation of Native CREST-a Cancer Research Experience and Student Training program for Navajo undergraduate students.  

PubMed

The Mayo Clinic Cancer Center and Diné College received funding for a 4-year collaborative P20 planning grant from the National Cancer Institute in 2006. The goal of the partnership was to increase Navajo undergraduates' interest in and commitment to biomedical coursework and careers, especially in cancer research. This paper describes the development, pilot testing, and evaluation of Native CREST (Cancer Research Experience and Student Training), a 10-week cancer research training program providing mentorship in a Mayo Clinic basic science or behavioral cancer research lab for Navajo undergraduate students. Seven Native American undergraduate students (five females, two males) were enrolled during the summers of 2008-2011. Students reported the program influenced their career goals and was valuable to their education and development. These efforts may increase the number of Native American career scientists developing and implementing cancer research, which will ultimately benefit the health of Native American people. PMID:23001889

Hughes, Christine A; Bauer, Mark C; Horazdovsky, Bruce F; Garrison, Edward R; Patten, Christi A; Petersen, Wesley O; Bowman, Clarissa N; Vierkant, Robert A

2013-03-01

367

Lessons Learned: Tribal Community Engagement, Remediation and Restoration of a Uranium Mine Tailings Site, Navajo Nation - 12484  

SciTech Connect

In May, 2011 New World Environmental Inc. was awarded a contract by the Navajo Nation Environmental Protection Agency to remediate an illegal radioactive waste disposal site located in the Navajo Nation. The initial scope included the excavation and shipment of an estimated 3,000 cubic yards of Uranium mine tailings and associated industrial waste. In this instance Stakeholders were supportive of the project, remediation and restoration, yet the movement of residual radioactive materials through tribal communities was a controversial issue. Other Stakeholder issues included site security, water sources for remediation activities, local residents' temporary re-location and care of livestock, right of way permissions and local workforce development. This presentation recaps the technical and non-technical issues encountered in the remediation and restoration the seven acre site and the outreach to surrounding communities. Cultural and equity issues resulting from historical problems associated with this and other sites in the immediate area and education and training. (authors)

Wadsworth, Donald K. [New World Environmental Inc., Livermore California 94550 (United States); Hicks, Allison H. [New World Environmental Inc., Irvine California 92614 (United States)

2012-07-01

368

Alkali solution treatment on sandstone cores  

E-print Network

' or 12 hours and then the cores were dried in an oven maintained at 212 F to remove any 0 remaining water or solvent. The dried samples were weighed and the physical dimensions were measured with a caliper. Each core was placed in a desiccator...ALKALI SOLUTION TREATMENT ON SANDSTONE CORES A Thesis by S UK J IN LEE Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE May 1978 Major Subject: Petroleum...

Lee, Suk Jin

1978-01-01

369

Facies control on sandstone composition (and influence of statistical methods on interpretations) in the John Henry Member, Straight Cliffs Formation,  

E-print Network

Facies control on sandstone composition (and influence of statistical methods on interpretations.J. Weltje Keywords: Sedimentary petrography Sandstone provenance Facies Univariate vs. multivariate that suggest distinct modal sandstone compositions. Detrital modes from six sandstone facies (upper shoreface

Johnson, Cari

370

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

371

A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago.  

PubMed

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 tail, the new fossil is the best-preserved predatory, non-avian dinosaur in Europe. It possesses a suite of characters that support its identification as a basal coelurosaur. A cladistic analysis indicates that the new taxon is closer to maniraptorans than to tyrannosauroids, grouping it with taxa often considered to be compsognathids. Large portions of integument are preserved along its tail. The absence of feathers or feather-like structures in a fossil phylogenetically nested within feathered theropods indicates that the evolution of these integumentary structures might be more complex than previously thought. PMID:16541071

Göhlich, Ursula B; Chiappe, Luis M

2006-03-16

372

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

373

Jurassic and triassic hydrocarbon exploration of southern Florida  

SciTech Connect

The Triassic and Jurassic of South Florida have been overlooked as a viable exploration target because of 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 shown that the Florida lower Paleozoic terrain is not akin to that of North America but is part of the West African Guinean Shield. Pre-Atlantic reconstruction of the Gulf of Mexico in this study suggests that there was a Florida connection to Yucatan-Cuba-Africa during the Triassic. This reconstruction also shows that Jurassic rocks 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 rifting of the North Atlantic Ocean and evidence from petrology of basement samples from deep wells, together with petrographic analyses of Jurassic sedimentary rocks, a Smackover-equivalent exploration play can be developed. Petrographic and petrophysical analysis of wells that have encountered Jurassic marine shales, anhydrite, dolomite, carbonate, and clastic sedimentary rocks has determined that they were deposited in shallow-water subtidal to supratidal environments. Excellent gas shows, oil stain in pores, and high TOC values in marine shales indicate that there are accumulations of hydrocarbon present. Application of analogous Gulf Coast Smackover stratigraphic models to this area, based on petrology and hydrogeology, should reduce risk and help define productive oil and gas reservoirs.

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

1994-12-31

374

Astronomical pacing of methane release in the Early Jurassic period  

Microsoft Academic Search

A pronounced negative carbon-isotope (delta13C) excursion of ~5-70\\/00 (refs 1-7) indicates the occurrence of a significant perturbation to the global carbon cycle during the Early Jurassic period (early Toarcian age, ~183 million years ago). The rapid release of 12C-enriched biogenic methane as a result of continental-shelf methane hydrate dissociation has been put forward as a possible explanation for this observation.

David B. Kemp; Angela L. Coe; Anthony S. Cohen; Lorenz Schwark

2005-01-01

375

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

376

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

377

Upper Jurassic depositional systems and hydrocarbon potential of southeast Mississippi  

SciTech Connect

Upper Jurassic sedimentation in southeast Mississippi was controlled by eustatic sea level fluctuations and locally modified by salt tectonism and basement structure. This study, using conventional core data and geophysical logs, indicates that a stable carbonate platform developed along the updip margin of the Mississippi interior salt basin. The basin was partially barred from the main Gulf of Mexico water mass by the Wiggins uplift, and became evaporitic during the Late Jurassic. Moldic, intercrystalline, and vuggy dolomite porosity is developed on the crests of intermediate and high-amplitude salt highs and on the Wiggins uplift. Jurassic source rocks are lower Smackover laminated lime mudstones. Migration into adjacent reservoirs postdated formation of porosity and the growth of salt anticlines, the most common trap type. A large potential Norphlet-Smackover gas play extends along the southern flank of the Wiggins uplift. Salt anticlines within the interior basin remain viable targets. Small oil discoveries should continue in stratigraphic traps, subtle salt structures, and basement blocks on the platform.

Meendsen, F.C.; Moore, C.H.; Heydari, E.; Sassen, R.

1987-09-01

378

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

379

Mesozoic infill of the Amu Darya Basin - the Jurassic & Cretaceous of the Kyzylkum and Nuratau regions, Uzbekistan  

NASA Astrophysics Data System (ADS)

The Southern Tien Shan extends for c. 2500 km along an E-W axis from Xinjiang in NW China as far as central Uzbekistan. It forms the northern boundary to a series of economically important basins along its margin (e.g. Tarim Basin, China: Amu Darya Basin, Uzbekistan). The earliest evidence for post-Amu Darya Basin initiation deposition is the fragmented record from the Kyzylkum region. The sediments are middle and upper Jurassic in age and were deposited in a lacustrine/marsh or possibly sheltered bay setting with adjacent alluvial fans shedding sheetlike aprons into the lake. These are overlain by Lower and Upper Cretaceous sediments, and former studies have suggested that the former comprises mainly marine units (in contrast to the continental of SE Uzbekistan) and the latter is mainly continental (again in contrast to the marine of SE Uzbekistan). In the study area the Middle Cretaceous (older sediments don't crop out) sediments were predominantly marine, with a variety of shelly fossils reported. The sediments are typical of shelf sandstones. The overlying Upper Cretaceous deposits are more nearshore in terms of environment, although clearly not continental (when compared to regions further to the NW). Thus, the clear subdivision from the literature could not be confirmed in outcrop, instead suggesting a broader marine influence across the area. In Cretaceous times, the region formed part of the westernmost area of the ancient Asian landmass bordered by the Tethys Ocean and the Turgai Strait.

McCann, Tom

2014-05-01

380

Jurassic plutons in the Desolation wilderness, northern Sierra Nevada batholith, California: A new segment in the Jurassic magmatic arc  

SciTech Connect

A 164[+-]7 Ma U-P zircon date establishes a Middle- to Late-Jurassic age for the Pyramid Peak granite and synplutonic dioritoids and hybrid rocks that comprise the Crystal Range suite, located southwest of Lake Tahoe. A Jurassic age is also assigned to the Keiths Dome quartz monzonite and the Desolation Valley and Camper Flat granodiorites (Loomis', 1983, Early Granitic Group) which are distinctly older than surrounding Cretaceous granitoids. The Keiths Dome quartz monzonite, the oldest pluton of the group, may be as old as 180 Ma and is distinguished by ductile shear zones and recrystallization textures which indicate an episode of deformation not undergone by other plutons. The Camper flat and Desolation Valley granodiorites are the youngest plutons of the group. ENE-trending microdiorite dikes filled extensional fractures, perpendicular to the direction of shortening, in all Jurassic plutons but on none of the Cretaceous bodies. Jurassic plutons may help constrain ages of metasedimentary and metavolcanic rocks and associated structures in the Mount Tallac roof pendant. The Pyramid Peak granite intrudes the Sailor Canyon Formation which bears Late Pliensbachian ammonites (Fisher, 1990), and the Keiths Dome quartz monzonite intrudes the overlying Tuttle Lake Formation and transects faults and shear zones in the pendant. Initial Sr isotope ratios for the Pyramid Peak granite range between 0.705427 and 0.706874, spanning the 0.706 value taken by some to mark the western limit of sialic lower crust. Data suggest an isotopically mixed source containing mantle and crustal components. Such an environment is not inconsistent with a passive continental margin where mafic magma invades rifted continental crust.

Sabine, C. (Desert Research Inst., Reno, NV (United States). Quaternary Sciences Center)

1993-04-01

381

Provenance of sandstones in the Golconda terrane, north central Nevada  

SciTech Connect

The upper Paleozoic Golconda terrane of north-central Nevada is a composite of several structurally bounded subterranes made of clastic, volcanic, and carbonate rocks. The clastic rocks provide important clues for the interpretation of the provenance and paleogeographic settings of the different lithologic assemblages found in these subterranes. Two petrographically distinct sandstones are identified in the Golconda terrane in the Osgood Mountains and the Hot springs Range of north-central Nevada. The sandstone of the Mississippian Farrel Canyon Formation, part of the Dry Hills subterrane, is characterized by quartzose and sedimentary and lithic-rich clasts with a small feldspar component. in contrast, the sandstone of the Permian Poverty Peak (II) subterrane is a silty quartzarenite with no lithic component, and a very limited feldspar component. The sandstone of the Farrel Canyon Formation is similar to nonvolcanic sandstones reported from elsewhere in the Golconda terrane. Modal data reflect a provenance of a recycled orogen and permit the interpretation that it could have been derived from the antler orogen as has been proposed for other sandstones of the golconda terrane. The sandstone of the Poverty Peak (II) subterrane is more mature than any of the other sandstones in either the Golconda terrane, the Antler overlap sequence, or the Antler foreland basin sequence. Modal data put the Poverty Peak (II) sandstone in the continental block provenance category. The distinct extrabasinal provenances represented in these different sandstones support the idea that the Golconda basin was made up of complex paleogeographic settings, which included multiple sources of extrabasinal sediment.

Jones, E.A. (Univ. of California, Berkeley (United States))

1991-02-01

382

Our Community -- Today and Yesterday. Book One (Nihil Hahoodzodoo -- Diijiidi doo Adaadaa. Naaltsoos T'aala'i Gone Yits'iligii). Fourth Grade Navajo Bilingual-Bicultural Social Studies Curriculum.  

ERIC Educational Resources Information Center

Presented in five chapters, book 1 of the Rough Rock fourth grade Navajo social studies program text is written in Navajo and English. The first chapter is on the community of Rough Rock (Arizona) illustrated by photographs of the community and people. Chapter II discusses the four elements (air, water, earth, and fire) the community needs to…

Bia, Fred; And Others

383

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. PMID:21576142

Kaptchuk, Ted J.

2011-01-01

384

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

385

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

386

Physical property changes of sandstones in Korea by supercritical CO2-sandstone-groundwater reaction at CO2 sequestration condition  

NASA Astrophysics Data System (ADS)

Lab scale experiments were performed to investigate physical property changes of sandstones by the dissolution reaction among supercritical CO2-sandstone-groundwater at sub-surface CO2 storage condition. High pressurized tank system was designed to create supercritical CO2 in the tank, simulating the sub-surface CO2 storage site. Three kinds of sandstones at Gyeongsang basin in Korea were sampled and they were cut into cylindrical cores (4.3 cm in diameter; 12 cm in height). A large stainless steel tank (2 liter of capacity) was used to create temperature and pressure conditions (50 oC and 100 bar) for CO2 sequestration, which was filled in with 1500 ml of groundwater and sandstone cores. For 60 days of reaction, physical properties of sandstones such as porosity, dry density, seismic velocity, and 1-D compression strength were measured to investigate the effect of supercritical CO2 on the sandstone at sequestration sites. The first-order dissolution coefficient (kd) of CO2-sandstone-groundwater reaction was calculated by measuring the change of the concentration of ions dissolved in groundwater and the weight of each sandstone core at the reaction time intervals. From the dissolution coefficient (kd), the dissolution time of 1 g per unit area (1 cm2) of each sandstone by CO2 injection was quantitatively predicted. The average porosity for sandstones was 8.183 % and it increased to 8.906 % after 60 days of the reaction. The average dry density, seismic velocity, and 1-D compression strength of sandstones decreased and these results were dependent on the porosity increase by the dissolution during the reaction. The average time to dissolve 1 g of B and C sandstones per unit area (1 cm2) was calculated as 1,525 years and 631 years, respectively, by using the first-order dissolution coefficient. From results, it was investigated that the physical property changes of sandstones at Gyeongsang basin in Korea rapidly occur when the supercritical CO2 is injected into CO2 sequestration sites.

Lee, M.; Kim, S.; Kim, J.; Wang, S.

2012-12-01

387

Solid As A Rock: The Utilization of Polyvinyl Acetate to Stabilize and Consolidate Museum Sandstone Objects  

E-print Network

Solid As A Rock: The Utilization of Polyvinyl Acetate to Stabilize and Consolidate Museum Sandstone) commonly used sandstone in creating various objects. Sandstone slabs used in hearth construction these objects unstable. Sandstone is a porous rock. The heat treatment and weathering drives off water and makes

Rock, Chris

388

Magnetostratigraphy of the Sherwood Sandstone Group (Lower and Middle Triassic), south Devon, UK  

E-print Network

Magnetostratigraphy of the Sherwood Sandstone Group (Lower and Middle Triassic), south Devon, UK; accepted 31 December 2002 Abstract The Sherwood Sandstone Group in south Devon consists of the Budleigh Salterton Pebble Beds and the Otter Sandstone Formation. The Otter Sandstone Formation comprises four

389

The same unique mutation in the arylsulfatase A gene causes late infantile metachromatic leukodystrophy in the Navajo and Western Eskimo populations  

SciTech Connect

Metachromatic leukodystrophy (MLD) is an autosomal recessive lysosomal disorder caused by defective catabolism of sulfatide, an important sphingolipid in myelin. Late infantile (LI), juvenile and adult patients with MLD are found throughout the world. Mutational analysis of the ARSA gene in patients with MLD has resulted in the identification of about 30 mutations. Recently we identified a mutation in the ARSA gene that was present in all Navajo Indian patients tested with LIMLD. All of the patients were homozygous for the G to A change at position 1 of intron 4 which causes aberrant splicing and a low level of ARSA mRNA. This mutation had not been found in any non-Navajo population. However, recently we were sent samples from two Alaskan Eskimo siblings with LIMLD. Sequencing of amplified genomic DNA showed that the affected siblings were homozygous for the above mutation. A simple DNA-based test will permit accurate patient and carrier identification in both the Eskimo and Navajo populations. Many studies have focused on the migrations of the Amerindian, Athapaskan and Eskimo from eastern Asia to the new world and the intermingling of these peoples. While it is clear that Na-Dene speaking Navajo split from other Athapaskan tribes and migrated from western Canada and Alaska to the southwest area of the United States, a direct genetic connection between the Western Eskimo and the Navajo has not been made. The presence of the same unique mutation causing a fatal inherited disease in both populations may point to interaction between these peoples prior to the migration of the Navajos south about 1000 years ago.

Pastor-Soler, N.M. [Jefferson Medical College, Philadelphia, PA (United States); Hu, D. [Tuba City Indian Medical Center, AZ (United States); Schertz, E. [Yukon-Kuskokwim Delta Regional Hospital, Bethel, AK (United States)

1994-09-01

390

Sequence stratigraphy of Jurassic strata in the lower Surat Basin succession, Queensland  

Microsoft Academic Search

The principles of non-marine sequence stratigraphy were applied to the Jurassic strata in the lower part of the Surat Basin, in order to better determine the depositional history of the basin and highlight potential reservoir and source rocks. The lithostratigraphic units in the Early-early Late Jurassic interval can be divided into three supersequences: J, K and L. Each supersequence consists

K. L. Hoffmann; J. M. Totterdell; O. Dixon; G. A. Simpson; A. T. Brakel; A. T. Wells; J. L. Mckellar

2009-01-01

391

Testing the fossil record: Sampling proxies and scaling in the British TriassicJurassic  

E-print Network

Testing the fossil record: Sampling proxies and scaling in the British Triassic­Jurassic Alexander March 2014 Available online 30 March 2014 Keywords: Palaeodiversity Fossil record Sampling Proxy Triassic Jurassic The quality of the fossil record varies immensely across taxa, geographic regions

Benton, Michael

392

A new large-bodied theropod dinosaur from the Middle Jurassic of Warwickshire, United Kingdom  

E-print Network

A new large-bodied theropod dinosaur from the Middle Jurassic of Warwickshire, United Kingdom ROGER dinosaur from the Middle Jurassic of Warwickshire, United Kingdom. Acta Palaeontologica Polonica 55 (1): 35-bodied theropod dinosaur, distinct from the contemporaneous Megalosaurus bucklandii. Cruxicheiros newmanorum gen

Cambridge, University of

393

2006 Nature Publishing Group A new carnivorous dinosaur from the Late Jurassic  

E-print Network

© 2006 Nature Publishing Group A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago Ursula B. Go¨hlich1 & Luis M. Chiappe2 Small Late Jurassic theropod dinosaurs are rare worldwide. In Europe these carnivorous dinosaurs are represented primarily by only two skeletons of Compsognathus1

Cai, Long

394

The first Lower Jurassic dinosaur from Scotland: limb bone of a ceratosaur theropod from Skye  

E-print Network

The first Lower Jurassic dinosaur from Scotland: limb bone of a ceratosaur theropod from Skye M. J right tibia of a carnivorous dinosaur is reported from the Lower Jurassic Broadford Beds Formation characteristic features of the ceratosaur theropods, a group of medium-sized predatory dinosaurs that were

Benton, Michael

395

Deep-tow study of magnetic anomalies in the Pacific Jurassic Quiet Zone  

E-print Network

The Jurassic Quiet Zone (JQZ) is a region of low amplitude, difficult-to-correlate magnetic anomalies located over Jurassic oceanic crust. We collected 1200 km of new deep-tow magnetic anomaly profiles over the Pacific JQZ that complement 2 deep...

Tominaga, Masako

2006-10-30

396

Jurassic\\/Cretaceous carbonate platform and reef dynamics of the Northern Calcareous Alps  

Microsoft Academic Search

Upper Jurassic to Lower Cretaceous carbonate platforms of the Northern Calcareous Alps are interpreted as steeply bordered, isolated Bahamian-type platforms, which are interfingered with bathypelagic basin sediments. This facies differentiation and the Upper Jurassic onset of carbonate platform development was caused by tectonic events at the Oxfordian\\/Kimmeridgian boundary. Gravitational sliding caused a structural relief within radiolarite basins that enabled the

M. W. Rasser; A. Fenninger

2003-01-01

397

Geological Society of America Paleogeographic and tectonic implications of Jurassic sedimentary  

E-print Network

-marine rocks as Jurassic instead of Triassic suggests a period of uplift and erosion or nondeposition extending from the Early Triassic into the Early Jurassic, followed by a return to marine conditions. Shallow-scale tectonic control on relative sea level related to a period of intra-arc extension or transtension. Schermer

Busby, Cathy

398

ELSEVIER Palaeogeography, Palaeoclimatology, Palaeoecology 136 (1997) 79-95 Palaeoenvironmental interpretation of a Triassic-Jurassic  

E-print Network

) 79-95 1. Introduction The close of the Triassic period is marked by one of the five largest mass Palaeoenvironmental interpretation of a Triassic-Jurassic boundary section from Western Austria based the Triassic-Jurassic boundary is described from near the village of Lori3ns in the Vorarlberg region

McRoberts, Christopher A.

399

Jurassic crustal deformation in west-central part of Colorado Plateau  

Microsoft Academic Search

Although the Jurassic Period is commonly thought of as a time of tectonic quiescence, updated isopach maps and new sedimentologic information indicate that it was a time of notable crustal deformation on the Colorado Plateau. A significant change in structural style occurred in Middle Jurassic time, especially during the erosion interval that produced the J-3 unconformity. Prior to late Middle

1985-01-01

400

Jurassic crustal deformation in west-central part of Colorado Plateau  

SciTech Connect

Although the Jurassic Period is commonly thought of as a time of tectonic quiescence, updated isopach maps and new sedimentologic information indicate that it was a time of notable crustal deformation on the Colorado Plateau. A significant change in structural style occurred in Middle Jurassic time, especially during the erosion interval that produced the J-3 unconformity. Prior to late Middle Jurassic time, the region had been tilted westward and structural troughs formed in the area of the present-day Circle Cliffs uplift and in the vicinity of the Circle Cliffs and Black Mesa regions were uplifted and the nearby Henry and Kaiparowits regions began to be downwarped as troughs or basins. It cannot be determined if or how the present-day monoclines flexed during the Jurassic. However, the direction of structural tilt across these areas changed from west side down to east side down during the late Middle and early Late Jurassic. The Monument region, the largest and most persistent structural element in the region, changed from a structural bench to a positive structure in the early Late Jurassic. In most cases the positive structures subsided more slowly than adjacent downwarps. Two exceptions during the Late Jurassic are the Black Mesa and Emery uplifts. These are the only uplifts that actually rose above the level of sediment accumulation. Jurassic rocks are not known to contain significant hydrocarbon resources in this region, but their tectonic history may offer clues to the structural history of underlying Paleozoic strata, which are the primary hydrocarbon exploration targets.

Peterson, F.

1985-05-01

401

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. PMID:22615359

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

402

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

403

An arboreal docodont from the Jurassic and mammaliaform ecological diversification.  

PubMed

A new docodontan mammaliaform from the Middle Jurassic of China has skeletal features for climbing and dental characters indicative of an omnivorous diet that included plant sap. This fossil expands the range of known locomotor adaptations in docodontans to include climbing, in addition to digging and swimming. It further shows that some docodontans had a diet with a substantial herbivorous component, distinctive from the faunivorous diets previously reported in other members of this clade. This reveals a greater ecological diversity in an early mammaliaform clade at a more fundamental taxonomic level not only between major clades as previously thought. PMID:25678661

Meng, Qing-Jin; Ji, Qiang; Zhang, Yu-Guang; Liu, Di; Grossnickle, David M; Luo, Zhe-Xi

2015-02-13

404

Detailed record of the mid-Oxfordian (Late Jurassic) positive carbon-isotope excursion in two hemipelagic sections (France  

E-print Network

Detailed record of the mid-Oxfordian (Late Jurassic) positive carbon-isotope excursion in two 2007 Abstract The Oxfordian (Late Jurassic) was a time of widespread change in Jurassic marine coincide with the first calcareous sediments recurring after a period of reduced carbonate accumulation

Gilli, Adrian

405

JurassicCretaceous low paleolatitudes from the circum-Black Sea region (Crimea and Pontides) due to True Polar Wander  

E-print Network

with respect to its core, and it was recently quantified. The period from 195­135 Ma (Early JurassicJurassic­Cretaceous low paleolatitudes from the circum-Black Sea region (Crimea and Pontides) due lower (15°) latitudes from Early Jurassic to Earliest Cretaceous at the position of Adria than suggested

Utrecht, Universiteit

406

Paleogeographic evidence on the Jurassic tectonic history of the Pontides: new paleomagnetic data from the Sakarya continent and Eastern Pontides  

Microsoft Academic Search

The Jurassic paleogeographic position of the Pontides is not well studied because of insufficient paleomagnetic data. For this reason, a paleomagnetic study was carried out in order to constrain the paleolatitudinal drift of the Turkish blocks during the Jurassic period. A total of 32 sites were sampled from volcanic and volcanoclastic rocks of the Lower\\/Middle Jurassic Kelkit formation (Eastern Pontides),

Mualla Cengiz Cinku

2010-01-01

407

Paleogeographic evidence on the Jurassic tectonic history of the Pontides: new paleomagnetic data from the Sakarya continent and Eastern Pontides  

Microsoft Academic Search

The Jurassic paleogeographic position of the Pontides is not well studied because of insufficient paleomagnetic data. For this reason, a paleomagnetic study was carried out in order to constrain the paleolatitudinal drift of the Turkish blocks during the Jurassic period. A total of 32 sites were sampled from volcanic and volcanoclastic rocks of the Lower\\/Middle Jurassic Kelkit formation (Eastern Pontides),

Mualla Cengiz Çinku

2011-01-01

408

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. PMID:23536443

Toljagi?, Olja; Butler, Richard J.

2013-01-01

409

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

410

Sandstone Acidizing Using Chelating Agents and their Interaction with Clays  

E-print Network

in the application of acidizing, coreflood tests were performed on Berea and Bandera sandstone cores. Another disadvantage of mud acid has been the fast spending at clay mineral surfaces leading to depletion of acid strength, migration of fines, and formation...

George, Noble Thekkemelathethil 1987-

2013-01-09

411

22. Sandstone abutment at foot of west approach. View to ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. Sandstone abutment at foot of west approach. View to northwest. - Selby Avenue Bridge, Spanning Short Line Railways track at Selby Avenue between Hamline & Snelling Avenues, Saint Paul, Ramsey County, MN

412

6. FIRST FLOOR, ROOM 1, BASEBOARD AND PLASTER OVERLAYING SANDSTONE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. FIRST FLOOR, ROOM 1, BASEBOARD AND PLASTER OVERLAYING SANDSTONE WALLS, LOOKING NORTHWEST - Taylor Run-Yorty Run Schoolhouse, Legislative Routes 62175 (PA Highway 481) & 62161, Monongahela, Washington County, PA

413

UNDERSIDE DETAIL WITH WEST ABUTMENT CONSTRUCTED OF RED COLORED SANDSTONE. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

UNDERSIDE DETAIL WITH WEST ABUTMENT CONSTRUCTED OF RED COLORED SANDSTONE. IN 1985, STEEL GIRDERS PAINTED BROWN REPLACED THE ORIGINAL TIMBER FLOOR SYSTEM. - Uhlerstown Bridge, Spanning Delaware Canal, Uhlerstown Hill Road, Uhlerstown, Bucks County, PA

414

18. View of east trestle approach and sandstone pier banded ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. View of east trestle approach and sandstone pier banded with concrete. View to southeast. - Selby Avenue Bridge, Spanning Short Line Railways track at Selby Avenue between Hamline & Snelling Avenues, Saint Paul, Ramsey County, MN

415

Chemical properties of Garnets from Garnet Ridge, Navajo volcanic field in the Colorado Plateau  

NASA Astrophysics Data System (ADS)

Significant amounts of garnet crystals have derived from kimberlitic diatremes at Garnet Ridge in northern Arizona. These garnets are chemically diverse and their origins have been still controversial. The diatremes at Garnet Ridge were dated at 30Ma (Smith et al., 2004). Coesite-bearing lawsonite eclogite reported by Usui et al., (2003) is important evidence for subduction of the Fallaron Plate below the Colorado plateau. This study characterized various kinds of garnets with several origins by petrographical observations and electron microprobe analyses (JXA-8900 WDS mode and JXA-733 EDS mode). On the basis of the chemical compositions and other features, the garnets were classified into the following 8 groups (A to H). Inclusions and exsolved phases were identified by laser Raman spectroscopy. (A) Garnet crystals (5-8 mm) with purple color are called ''Navajo Ruby''. A significant amount of Cr2O3 is a typical feature (up to ~5.9 wt. %). These garnet were rich in pyrope (66-78 mol. %). Olivine, Cpx, and exsolved lamellae of rutile were contained. (B) Reddish brown garnets were Pyp-rich (60-75 mol. %), and contained a minor amount of Cr2O3 (less than ~1 wt. %). The inclusions were rod-shaped rutile , Cpx, Opx, zircon, olivine and exsolved lamellae of apatite. (C) Garnet megacrysts (8-12 cm) were plotted near the center of Prp-Alm-Grs triangle (Pyp30-35 Alm28-33 Grs29-35). Exsolved apatite lamellae were confirmed. (D) Some of reddish brown garnets were plotted on same area as the Type-C. (E) Garnets in eclogite have Alm-rich composition (Pyp6-22 Alm52-65 Grs16-42). They clearly showed prograde chemical zonation; MgO: 1.4 to 5.4 wt. %, CaO: 14.0 to 5.6 wt. % both from core to rim. (F) Garnets in altered or metasomatized eclogite had a wide range of chemical composition (Pyp7-38 Alm52-69 Grs4-31) with similar prograde zonation. The cores were plotted near the rim of Type-E garnet. (G) Garnets in unidentified rock (strongly altered) had Alm-rich composition near Alm-Prp join. Euhedral quartz and zircon were included in the garnet. (H) Garnets in skarn-like rock of metasomatism origin at crustal level were plotted on Alm-Grs join and have no Prp component. Titanite, zoisite and fluid inclusion were identified in this garnet. Among the garnets described above, one of the typical garnets from Garnet Ridge is Cr-bearing Pyp-rich garnet, "Navajo Ruby", of peridotite origin at great depths, and another typical one is garnet in eclogite probably of subducted Farallon Plate origin. These two rocks having strong contrast each other were mixed underneath the Colorado Plateau. The chemical characteristics and petrographical features of the garnets from Garnet Ridge will give us very important information on complex petrochemical processes and related environments underneath the Colorado Plateau. Acknowledgements: The authors are grateful to Mrs. Pauline Deswudt who sold us various kinds of garnet grains and their host rocks for the present study. References: D. Smith, James N. Connelly, Kathryn Manser, Desmond E. Moser, Todd B. Housh, Fred W. McDowell, and Lawrence E. Mack., Vol. 5, Number 4. (2004) Geochemistry Geophysics Geosystems Usui, T., Nakamura, E., Kobayashi, K., Maruyama, S. and Helmstaedt, H. (2003) Geology, 31.

Koga, I.; Ogasawara, Y.

2012-12-01

416

The sliding characteristics of sandstone on quartz fault-gouge  

Microsoft Academic Search

Summary Three types of triaxial compression experiments are used to characterize the frictional processes during sliding on quartz gouge. They are: 1) pre-cut Tennessee Sandstone sliding on an artificial layer of quartz gouge; 2) fractured Coconino Sandstone sliding along experimentally produced shear fractures; and 3) a fine-grained quartz aggregate deformed in compression. The specimens were deformed to 2.0 kb confining

JAMES T. ENGELDERZ; John M. Logan; John Handin

1975-01-01

417

Depositional environment of downdip Yegua (Eocene) sandstones, Jackson County, Texas  

E-print Network

DEPOSITIONAL ENVIRONMENT OF DONNDIP YEGUA (EOCENE) SANDSTONES, JACKSON COUNTY, TEXAS A Thesis by CHRISTOPHER JAMES WHITTEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1988 Major Subject: Geology DEPOSITIONAL ENVIRONMENT QF DOWNDIP YEGUA (EOCENE) SANDSTONES, JACKSON COUNTY, TEXAS A Thesis by CHRISTOPHER JAMES WHITTEN Approved as to style and content by: Robert R. Berg (Chair of Committee...

Whitten, Christopher James

2012-06-07

418

Provenance and geochronology of Cenozoic sandstones of northern Borneo  

NASA Astrophysics Data System (ADS)

The Crocker Fan of Sabah was deposited during subduction of the Proto-South China Sea between the Eocene and Early Miocene. Collision of South China microcontinental blocks with Borneo in the Early Miocene terminated deep water sedimentation and resulted in the major regional Top Crocker Unconformity (TCU). Sedimentation of fluvio-deltaic and shallow marine character resumed in the late Early Miocene. The Crocker Fan sandstones were derived from nearby sources in Borneo and nearby SE Asia, rather than distant Asian and Himalayan sources. The Crocker Fan sandstones have a mature composition, but their textures and heavy mineralogy indicate they are first-cycle sandstones, mostly derived from nearby granitic source rocks, with some input of metamorphic, sedimentary and ophiolitic material. The discrepancy between compositional maturity and textural immaturity is attributed to the effects of tropical weathering. U-Pb ages of detrital zircons are predominantly Mesozoic. In the Eocene sandstones Cretaceous zircons dominate and suggest derivation from granites of the Schwaner Mountains of southern Borneo. In Oligocene sandstones Permian-Triassic and Palaeoproterozoic zircons become more important, and are interpreted to be derived from Permian-Triassic granites and Proterozoic basement of the Malay Tin Belt. Miocene fluvio-deltaic and shallow marine sandstones above the TCU were mostly recycled from the deformed Crocker Fan in the rising central mountain range of Borneo. The provenance of the Tajau Sandstone Member of the Lower Miocene Kudat Formation in north Sabah is strikingly different from other Miocene and older sandstones. Sediment was derived mainly from granitic and high-grade metamorphic source rocks. No such rocks existed in Borneo during the Early Miocene, but potential sources are present on Palawan, to the north of Borneo. They represent continental crust from South China and subduction-related metamorphic rocks which formed an elevated region in the Early Miocene which briefly supplied sediment to north Sabah.

van Hattum, M. W. A.; Hall, R.; Pickard, A. L.; Nichols, G. J.

2013-10-01

419

Permeability prediction and drainage capillary pressure simulation in sandstone reservoirs  

E-print Network

PERMEABILITY PREDICTION AND DRAINAGE CAPILLARY PRESSURE SIMULATION IN SANDSTONE RESERVOIRS A Dissertation by TAO WU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of DOCTOR OF PHILOSOPHY December 2004 Major Subject: Geology PERMEABILITY PREDICTION AND DRAINAGE CAPILLARY PRESSURE SIMULATION IN SANDSTONE RESERVOIRS A Dissertation by TAO WU Submitted to Texas A&M University...

Wu, Tao

2005-02-17

420

Experimental study of stick-slip in Tennessee sandstone  

E-print Network

EXPERIMENTAL STUDY OF STICK-SLIP IN TENNESSEE SANDSTONE A Thesis by JOHN ARTHUR HUMSTON Submitted to the Graduate College of Texas AFM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1972... Major Subject: Geology EXPERIMENTAL STUDY OF STICK-SLIP IN TENNESSEE SANDSTONE A Thesis by JOHN ARTHUR HUMSTON Approved as to style and content by: Chair an Committee Member Head of Department August 1972 ABSTRACT Experimental Study of Stick...

Humston, John Arthur

2012-06-07

421

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

422

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

423

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

424

Amphibious flies and paedomorphism in the Jurassic period.  

PubMed

The species of the Strashilidae (strashilids) have been the most perplexing of fossil insects from the Jurassic period of Russia and China. They have been widely considered to be ectoparasites of pterosaurs or feathered dinosaurs, based on the putative presence of piercing and sucking mouthparts and hind tibio-basitarsal pincers purportedly used to fix onto the host's hairs or feathers. Both the supposed host and parasite occur in the Daohugou beds from the Middle Jurassic epoch of China (approximately 165 million years ago). Here we analyse the morphology of strashilids from the Daohugou beds, and reach markedly different conclusions; namely that strashilids are highly specialized flies (Diptera) bearing large membranous wings, with substantial sexual dimorphism of the hind legs and abdominal extensions. The idea that they belong to an extinct order is unsupported, and the lineage can be placed within the true flies. In terms of major morphological and inferred behavioural features, strashilids resemble the recent (extant) and relict members of the aquatic fly family Nymphomyiidae. Their ontogeny are distinguished by the persistence in adult males of larval abdominal respiratory gills, representing a unique case of paedomorphism among endopterygote insects. Adult strashilids were probably aquatic or amphibious, shedding their wings after emergence and mating in the water. PMID:23426262

Huang, Diying; Nel, André; Cai, Chenyang; Lin, Qibin; Engel, Michael S

2013-03-01

425

Jurassic extension and Alpine inversion of the northern Morocco  

SciTech Connect

The lower Mesozoic half grabens of northern Morocco form part of an extensional system that is related to the opening of the western Tethys. They appear to be somewhat younger than the Triassic-Jurassic systems associated with the opening the Atlantic Ocean. During the Tertiary and as consequence of the Alpine collision of Africa with Europe, these half graben systems were inverted as shown by the High and the Middle Atlas mountains. Seismic illustrations of similar but smaller inversion structures are available from the Guercif area and the [open quotes]Rides Prerifaines[close quotes] of northern Morocco. These seismic profiles serve as small models for the much larger Atlas Mountains. In the Guercif area, the inversions are limited in scope, but in the [open quotes]Ride Prerifaines[close quotes] are extensive decollement systems that sole out in the Triassic evaporites. These systems evolve into complex thrust faults and associated lateral ramps that are strongly influenced by the configuration of the Jurassic transtensional systems. Significant hydrocarbon accumulation have been known for some time from the [open quotes]Rides Prerifaines.[close quotes] A review of the geometry of the inverted half-graben systems, combined with detailed stratigraphic studies, is likely to lead to the discovery of additional reserves in the area.

Zizi, M. (Rice Univ., Houston, TX (United States))

1993-09-01

426

A Jurassic ceratosaur from China helps clarify avian digital homologies.  

PubMed

Theropods have traditionally been assumed to have lost manual digits from the lateral side inward, which differs from the bilateral reduction pattern seen in other tetrapod groups. This unusual reduction pattern is clearly present in basal theropods, and has also been inferred in non-avian tetanurans based on identification of their three digits as the medial ones of the hand (I-II-III). This contradicts the many developmental studies indicating II-III-IV identities for the three manual digits of the only extant tetanurans, the birds. Here we report a new basal ceratosaur from the Oxfordian stage of the Jurassic period of China (156-161 million years ago), representing the first known Asian ceratosaur and the only known beaked, herbivorous Jurassic theropod. Most significantly, this taxon possesses a strongly reduced manual digit I, documenting a complex pattern of digital reduction within the Theropoda. Comparisons among theropod hands show that the three manual digits of basal tetanurans are similar in many metacarpal features to digits II-III-IV, but in phalangeal features to digits I-II-III, of more basal theropods. Given II-III-IV identities in avians, the simplest interpretation is that these identities were shared by all tetanurans. The transition to tetanurans involved complex changes in the hand including a shift in digit identities, with ceratosaurs displaying an intermediate condition. PMID:19536256

Xu, Xing; Clark, James M; Mo, Jinyou; Choiniere, Jonah; Forster, Catherine A; Erickson, Gregory M; Hone, David W E; Sullivan, Corwin; Eberth, David A; Nesbitt, Sterling; Zhao, Qi; Hernandez, Rene; Jia, Cheng-kai; Han, Feng-lu; Guo, Yu

2009-06-18

427

Harris et al., eds., 2006, The Triassic-Jurassic Terrestrial Transition. New Mexico Museum of Natural History and Science Bulletin 37. THE MOENAVE FORMATION AT THE ST. GEORGE DINOSAUR DISCOVERY SITE AT  

E-print Network

area resulted in the temporary exposure of fresh rock at and near the St. George Dinosaur Discovery Site at Johnson Farm (SGDS), facilitating examination and description of the Lower Jurassic stratigraphy of the vicinity in some detail. Since this study, construction has covered much of what we observed, making this the only detailed record of the Moenave Formation in the SGDS area. We measured a total thickness for the Moenave Formation of 73.97 m. The formation is divided into a lower Dinosaur Canyon Member (56.41 m thick) and upper Whitmore Point Member (17.56 m thick). A poorly cemented chert and anhydrite pebble conglomerate approximately 1 m thick overlies an unconformable contact (J-0 unconformity of previous authors) of the Moenave with the older (Late Triassic) Chinle Formation. Overlying the conglomerate is 34.8 m of slope-forming, mudstone-dominated rocks with anhydrite nodules and secondary gypsum veins in the lower portion, and thin, ripple-bedded sandstone layers with mudcracks that become increasingly abundant up-section. Fine- to medium-grained sandstone beds, each 10 to 100 cm thick, constitute a ledge-forming sandstone unit 18.9 m thick at the top of the Dinosaur Canyon Member. Medium-scale trough cross-bedding characterizes the thicker beds in the lower half, and ripple-drift cross-bedding that preserves dinosaur tracks dominates the beds near the top. A poorly sorted, yellowish-tan to green sandstone bed 5 m from the top preserves abundant, identifiable plant debris.

James I. Kirkland; Andrew; R. C. Milner

428

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.

429

Reservoir characterization of Pennsylvanian sandstone reservoirs  

SciTech Connect

The overall objectives of this work are: (1) to investigate the importance of various qualities and quantities of data on the optimization of water flooding performance; and (2) to study the application of newly developed, geostatistical techniques to analyze available production data to predict future prospects of infill drilling. Specifically, to satisfy our first objective, we will study the feasibility of applying fractal geometry concepts to characterize individual formations; develop a three-dimensional conditional simulation program to define reservoir properties at various scales; establish a method to integrate the data collected at various scales including the well test and the core data; and to investigate the utility of outcrop data in describing subsurface reservoir details. To satisfy the second objective, we will investigate various techniques to utilize the production data, including initial potential and the production decline, in proposing a possible location for a future infill well. The techniques investigated will include geostatistical and time-series analyses. The study will be restricted to Pennsylvanian sandstone reservoirs commonly found in Oklahoma. 2 refs.

Kelkar, B.G.

1991-01-01

430

Reservoir characterization of Pennsylvanian sandstone reservoirs  

SciTech Connect

The overall objectives of this work are: (i) to investigate the importance of various qualities and quantities of data on the optimization of water flooding performance; and (ii) to study the application of newly developed, geostatistical techniques to analyze available production data to predict future prospects of infill drilling. Specifically to satisfy our first objective, we will study the feasibility of applying fractal geometry concepts to characterize individual formations; develop a three-dimensional conditional simulation program to define reservoir properties at various scales; establish a method to integrate the data collected at various scales including the well test and the core data; and to investigate the utility of outcrop data in describing subsurface reservoir details. To satisfy the second objective, we will investigate various techniques to utilize the production data, including initial potential and the production decline, in proposing a possible location for a future infill well. The techniques investigated will include geostatistical analyses. The study will be restricted to Pennsylvanian sandstones reservoirs commonly found in Oklahoma.

Kelkar, B.G.

1995-03-01

431

Deep-tow magnetic anomaly study of the Pacific Jurassic Quiet Zone and implications for the geomagnetic polarity reversal timescale and  

E-print Network

., 113, B07110, doi:10.1029/2007JB005527. 1. Introduction [2] The Jurassic period appears to be a time of the Jurassic magnetic field. It was once suggested that this Jurassic ``Quiet Zone'' (JQZ) reflects a periodDeep-tow magnetic anomaly study of the Pacific Jurassic Quiet Zone and implications

432

Astronomical constraints on the duration of the early Jurassic Hettangian stage and recovery rates following the end-Triassic mass extinction  

E-print Network

for the base of the Jurassic period and the duration of lower Jurassic stages largely vary between studiesAstronomical constraints on the duration of the early Jurassic Hettangian stage and recovery rates Available online 10 May 2010 Editor: P. DeMenocal Keywords: Triassic Jurassic cyclostratigraphy astronomical

Utrecht, Universiteit

433

Population trends of the mancos saltbrush, proatriplex pleiantha from 1991 to 1995, Navajo Mine, Northwest New Mexico  

SciTech Connect

The Mancos Saltbrush, Proatriplex pleiantha is of concern of Navajo Mine, BHP Minerals due to its potential status as a threatened plant species. The occurrence of this plant within its natural range however, is strongly influenced by climatic conditions in the Spring. Seeds may remain viable in the soil for up to 10 years, thereby avoiding unfavorable years. Documentation of the plants occurrence and population trends at seven permanent monitoring sites were recorded by Marron Tasheck Knight, Inc. in 1991 and 1992 and by Buchanan Consultants, Ltd. in May 1993 and 1994. Six of the sites are located just outside the Navajo Mine lease boundaries and the seventh site in the Four Couners Region of New Mexico just south of the Colorado border. Results to date show a general decrease in P. pleiantha site size, number of plants at the site, plant size and plant density. There were no plants observed at any of the sites in 1994. Population data collected at sites in 1991, 1993 and 1994 show a decrease from 1992. These decreases are most likely due to unfavorable climatic conditions during the period of seed germination in 1991, 1993, and 1994. Climate during the Spring of 1993 and 1994 was dry and warm compared to wet, warm conditions in 1992 and to a lesser degree in 1991. A cool, wet spring climate appears to favor P. pleiantha germination.

Hyder, D.; Buchanan, B.A. [Buchanan Consultants, Ltd., Farmington, NM (United States); Estrada, O.J. [Navajo Mine, Fruitland, NM (United States)] [and others

1995-09-01

434

In the Eyes of the Beholder: Understanding and Resolving Incompatible Ideologies and Languages in US Environmental and Cultural Laws in Relationship to Navajo Sacred Lands  

ERIC Educational Resources Information Center

In this article, the author raises a few examples of incompatible concepts and languages in US federal environmental and cultural laws affecting the management of indigenous sacred lands. She explains these examples by describing the management of a selection of Navajo (Dine) sacred places and elsewhere. Through fundamental concepts rooted in…

Milholland, Sharon

2010-01-01

435

A 122.5Kilobase Deletion of the P Gene Underlies the High Prevalence of Oculocutaneous Albinism Type 2 in the Navajo Population  

Microsoft Academic Search

Oculocutaneous albinism (OCA) is a genetically heterogeneous disorder. There are four known types of OCA: OCA1-OCA4. The clinical manifestations of all types of OCA include skin and hair hypopigmentation and visual impairment. Although there are a few documented observations of high frequency of albinism among Native Americans, including the Hopi, Zuni, Kuna, Jemez, Laguna, San Juan, and Navajo, no causative

Zanhua Yi; Nanibaa’ Garrison; Orit Cohen-Barak; Tatiana M. Karafet; Richard A. King; Robert P. Erickson; Michael F. Hammer; Murray H. Brilliant

2003-01-01

436

The Law of the People (Dine Bibee Haz'Aannii): A Bicultural Approach to Legal Education for Navajo Students, Volume 3.  

ERIC Educational Resources Information Center

Volume 3 in a 4-volume bilingual bicultural law-related curriculum concerns Navajo traditional law as it pertains to the family, and compares these laws and customs to those of Anglo society. Case histories (gathered using anthropological field techniques) were compiled by paraprofessional legal advocates, and provide materials to be used in…

Vicenti, Dan; And Others

437

Bedrock and surficial geologic map of the Satan Butte and Greasewood 7.5’ quadrangles, Navajo and Apache Counties, northern Arizona  

USGS Publications Warehouse

The geologic map of the Satan Butte and Greasewood 7.5’ quadrangles is the result of a cooperative effort of the U.S. Geological Survey (USGS) and the Navajo Nation to provide regional geologic information for management and planning officials. This map provides geologic information useful for range management, plant and animal studies, flood control, water resource investigations, and natural hazards associated with sand-dune mobility. The map provides connectivity to the regional geologic framework of the Grand Canyon area of northern Arizona. The map area encompasses approximately 314 km2 (123 mi2) within Navajo and Apache Counties of northern Arizona and is bounded by lat 35°37'30" to 35°30' N., long 109°45' to 110° W. The quadrangles lie within the southern Colorado Plateau geologic province and within the northeastern portion of the Hopi Buttes (Tsézhin Bií). Large ephemeral drainages, Pueblo Colorado Wash and Steamboat Wash, originate north of the map area on the Defiance Plateau and Balakai Mesa respectively. Elevations range from 1,930 m (6,330 ft) at the top of Satan Butte to about 1,787 m (5,860 ft) at Pueblo Colorado Wash where it exits the southwest corner of the Greasewood quadrangle. The only settlement within the map area is Greasewood, Arizona, on the north side of Pueblo Colorado Wash. Navajo Highway 15 crosses both quadrangles and joins State Highway 264 northwest of Ganado. Unimproved dirt roads provide access to remote parts of the Navajo Reservation.

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

2013-01-01

438

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

439

Geomagnetic field intensity in the middle jurassic - oligocene  

E-print Network

The present paper summarizes results of the studies on the intensity of geomagnetic field in the (167 - 23) Ma interval by sedimentary rocks of the Russian Plate and adjacent territories. The joint analysis of the data paleointensity obtained by sedimentary and thermomagnetized (from PINT12) rocks within this temporal interval is conducted. It is shown that the changes of the paleointensity were occurred chaotically. Alternating bursts and periods of quiet regime of the geomagnetic field are typical for intermittent processes and is a characteristic of the geological interval Jurassic-beginning of Paleogene. The distributions of the paleointensity corresponding to different intervals of geologic time were investigated. It is revealed that the cumulative distribution function (CDF) of the paleointensity values is best approximated by a power function. The indices of the power functions varied depending on geologic time intervals.The analysis of the paleomagnetic data suggests that the medium in which the geoma...

Kurazhkovskii, A Yu; Klain, B I

2014-01-01

440

Three new Jurassic euharamiyidan species reinforce early divergence of mammals.  

PubMed

The phylogeny of Allotheria, including Multituberculata and Haramiyida, remains unsolved and has generated contentious views on the origin and earliest evolution of mammals. Here we report three new species of a new clade, Euharamiyida, based on six well-preserved fossils from the Jurassic period of China. These fossils reveal many craniodental and postcranial features of euharamiyidans and clarify several ambiguous structures that are currently the topic of debate. Our phylogenetic analyses recognize Euharamiyida as the sister group of Multituberculata, and place Allotheria within the Mammalia. The phylogeny suggests that allotherian mammals evolved from a Late Triassic (approximately 208 million years ago) Haramiyavia-like ancestor and diversified into euharamiyidans and multituberculates with a cosmopolitan distribution, implying homologous acquisition of many craniodental and postcranial features in the two groups. Our findings also favour a Late Triassic origin of mammals in Laurasia and two independent detachment events of the middle ear bones during mammalian evolution. PMID:25209669

Bi, Shundong; Wang, Yuanqing; Guan, Jian; Sheng, Xia; Meng, Jin

2014-10-30

441

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

NASA Astrophysics Data System (ADS)

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.

Neukum, Christoph; Braun, Anika; Azzam, Rafig

2014-08-01

442

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

443

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

444

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

445

Fast evolving conduits in clay-bonded sandstone: Characterization, erosion processes and significance for the origin of sandstone landforms  

NASA Astrophysics Data System (ADS)

In Strelec Quarry, the Czech Republic, an underground conduit network > 300 m long with a volume of ~ 104 m3 and a catchment of 7 km2 developed over 5 years by groundwater flow in Cretaceous marine quartz sandstone. Similar landforms at natural exposures (conduits, slot canyons, undercuts) are stabilized by case hardening and have stopped evolving. The quarry offers a unique opportunity to study conduit evolution in sandstone at local to regional scales, from the initial stage to maturity, and to characterize the erosion processes which may form natural landforms prior to stabilization. A new technique was developed to distinguish erodible and non-erodible sandstone surfaces. Based on measurements of relative erodibility, drilling resistance, ambient and water-saturated tensile strength (TS) at natural and quarry exposures three distinct kinds of surfaces were found. 1) Erodible sandstone exposed at ~ 60% of surfaces in quarry. This sandstone loses as much as 99% of TS when saturated. 2) Sub-vertical fracture surfaces that are non-erodible already prior to exposure at ground surface and which keep considerable TS if saturated. 3) Case hardened surfaces that start to form after exposure. In favorable conditions they became non-erodible and reach the full TS in just 6 years. An increase in the hydraulic gradient from ~ 0.005 to > 0.02 triggered conduit evolution, based on long-term monitoring of water table in 18 wells and inflows to the quarry. Rapidly evolving major conduits are characterized by a channel gradient of ~ 0.01, a flow velocity ~ 40 cm/s and sediment concentration ~ 10 g/l. Flow in openings with a discharge 1 ml/s and hydraulic gradient > 0.05 exceeds the erosion threshold and initiates piping. In the first phase of conduit evolution, fast concentrated flow mobilizes erodible sandstone between sets of parallel fractures in the shallow phreatic zone. In the second phase the conduit opening mainly expands vertically upward into the vadose zone by mass wasting of undercut sandstone slabs. Mass wasting is responsible for > 90% of mobilized sandstone. Sides of the mature conduits are protected by non-erodible fracture surfaces. Natural landforms were probably formed very rapidly by overland flow, piping and possibly fluidization during or at the end of the glacial periods when sandstone was not yet protected by case hardening.

Bruthans, Jiri; Svetlik, Daniel; Soukup, Jan; Schweigstillova, Jana; Valek, Jan; Sedlackova, Marketa; Mayo, Alan L.

2012-12-01

446

Fe-Ni Micrometorites from Upper Jurassic Cañadon Asfalto Fm., Patagonia, Argentina  

NASA Astrophysics Data System (ADS)

Microspherules from an upper Jurassic sediments from Patagonia, show mineralogical, geochemical and textural features very similar to those reported for I-type micrometeorites whereas some spherules are interpreted as typical G-type micrometeorites.

Matteini, M.; Hauser, N.; Cabaleri, N.; Silva Nieto, D.; Cuadros, F. A.; Reyes, S.

2014-09-01

447

Paleobiology and skeletochronology of Jurassic dinosaurs: implications from the histology and oxygen  

E-print Network

Paleobiology and skeletochronology of Jurassic dinosaurs: implications from the histology Abstract Fossil biogenic phosphate of fast-growing primary bone tissue of dinosaurs can preserve dinosaurs with different histologic patterns of bone growth, high-resolution oxygen isotope profiles were

Schöne, Bernd R.

448

Jurassic sequences of the Hebrides Basin, Isle of Skye, Scotland STEPHEN P. HESSELBO*  

E-print Network

Jurassic sequences of the Hebrides Basin, Isle of Skye, Scotland STEPHEN P. HESSELBO* and ANGELA L the Outer Isles to the mainland SE of Skye, showing structural disposition of the main Mesozoic sedimentary

Hesselbo, Stephen P.

449

A new Bathonian (Middle Jurassic) microvertebrate site, within the Chipping Norton Limestone Formation at Hornsleasow Quarry,  

E-print Network

the palaeokarst and overlying soils (with their indigenous flora and fauna) suggest a period of emergence the older forms of the Triassic and Early Jurassic (prosauropods, small theropods, basal ornithischians

Benton, Michael

450

The Lower Jurassic of the Eastern Caspian region and the Middle Caspian Basin: Lithology, facies, taphonomy  

NASA Astrophysics Data System (ADS)

Lithofacies of the productive Upper Triassic-Lower Jurassic deposits of the Eastern Caspian region, studied in wells on the Caspian coast and exposed in the outcrops of the Mountainous Mangyshlak, are described and analyzed. The similarity of the structure of the Mesozoic sedimentary beds of the Middle Caspian Basin and of those of the land adjacent to its eastern coast is confirmed. Comparative analysis of lithofacies allowed the reconstruction of the paleogeographic setting and depositional environments in the studied region during the Early Jurassic. A unique fossil plant occurrence is discovered in the upper part of the Lower Jurassic series (in the lower subformation of the Kokala Formation; Eastern Caspian region). Fossil plant taphonomy and the lithology of host rocks in the occurrence resulted from unusual paleogeographic settings that existed in the Middle Caspian Basin at the time of the Early-Middle Jurassic boundary.

Kiritchkova, A. I.; Nosova, N. V.

2014-09-01

451

Narratives of location: School science identities and scientific discourse among Navajo women at the University of New Mexico  

NASA Astrophysics Data System (ADS)

This research examines the interplay of scientific discourse and students' sense of self among four Navajo (Dine) women as they major in science at a university in the southwestern United States. This dissertation research is an ethnographic case study of Navajo women as they were completing their final year of undergraduate study in the life sciences at a university. How do Navajo women express their identity in Western science at the university? What role does scientific discourse play in this process? This research employs a feminist poststructural approach to language and expands the way discourse has typically been addressed in science education. I expand the notion of discourse through poststructuralism by recognizing the co-constitutive role of language in fashioning realities and generating meaning. Data sources in this study included transcripts from one-on-one interviews, electronic correspondence (e-mail), observations of social contexts on campus, students' writing for science courses, university policy statements, departmental outcomes assessments, web profiles of student research in science, and a researcher's reflective journal. This study took place beginning in January 2002 and continued through May of 2003 at the University of New Mexico. After completing the thematic (constant comparative analysis) and an analysis of metaphors, I "retold" or "restoried" the narratives collected during interviews. In the cross case analysis, I compared each participant's description of those discursive spaces that afforded engagement with science, and those locations where their awareness of academic language was heightened in a process of metadiscourse. I identified these spaces as locations of possibility in which students and their mentors (or instructors) valued connected knowing, acknowledged each other's history, culture, and knowledge, and began speaking to each other subject-to-subject to challenge normative views of schooling. The participants in this research located spaces in which they authored themselves: study groups, a research project on invasive plants, the American Indian Medial Association, and a community college. The women in this study selectively accommodated elements of Western science that were consistent with their identity as they positioned themselves in service to family, community, and tribe, and also sought positions beyond the objectified gaze of the institution.

Brandt, Carol B.

452

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

453

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. PMID:22870244

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

2012-01-01

454

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

455

Microbial contamination of two urban sandstone aquifers in the UK.  

PubMed

Development of urban groundwater has historically been constrained by concerns about its quality. Rising urban water tables and overabstraction from rural aquifers in the UK have led to a renewed interest in urban groundwater, particularly the possibility of finding water of acceptable quality at depth. This study assessed the microbial quality of groundwater collected from depth-specific intervals over a 15-month period within the Permo-Triassic Sherwood Sandstone aquifers underlying the cities of Nottingham and Birmingham. Sewage-derived bacteria (thermotolerant coliforms, faecal streptococci and sulphite-reducing clostridia) and viruses (enteroviruses, Norwalk-like viruses, coliphage) were regularly detected to depths of 60 m in the unconfined sandstone and to a depth of 91 m in the confined sandstone. Microbial concentrations varied temporally and spatially but increased frequency of contamination with depth coincided with geological heterogeneities such as fissures and mudstone bands. Significantly, detection of Norwalk-like viruses and Coxsackievirus B4 in groundwater corresponded with seasonal variations in virus discharge to the sewer system. The observation of low levels of sewage-derived microbial contaminants at depth in the Triassic Sandstone aquifer is explained by the movement of infinitesimal proportions of bulk (macroscopic) groundwater flow along preferential pathways (e.g., fissures, bedding planes). The existence of very high microbial populations at source (raw sewage) and their extremely low detection limits at the receptor (multilevel piezometer) enable these statistically extreme (microscopic) flows to be traced. Rapid penetration of microbial contaminants into sandstone aquifers, not previously reported, highlights the vulnerability of sandstone aquifers to microbial contamination. PMID:12502063

Powell, Karen L; Taylor, Richard G; Cronin, Aidan A; Barrett, Mike H; Pedley, Steve; Sellwood, Jane; Trowsdale, Sam A; Lerner, David N

2003-01-01

456

Fluvial-deltaic sedimentation and stratigraphy of the ferron sandstone  

USGS Publications Warehouse

East-central Utah has world-class outcrops of dominantly fluvial-deltaic Turonian to Coniacian aged strata deposited in the Cretaceous foreland basin. The Ferron Sandstone Member of the Mancos Shale records the influences of both tidal and wave energy on fluvial-dominated deltas on the western margin of the Cretaceous western interior seaway. Revisions of the stratigraphy are proposed for the Ferron Sandstone. Facies representing a variety of environments of deposition are well exposed, including delta-front, strandline, marginal marine, and coastal-plain. Some of these facies are described in detail for use in petroleum reservoir characterization and include permeability structure.

Anderson, P.B.; Chidsey, T.C., Jr.; Ryer, T.A.

1997-01-01

457

Elevated Uranium in Aquifers of the Jacobsville Sandstone  

NASA Astrophysics Data System (ADS)

The EPA has announced a new standard for uranium in drinking water of 30 parts per billion (ppb). This maximum contaminant level (MCL) takes effect for community water supplies December 2003. The EPA's ruling has heightened awareness among residential well owners that uranium in drinking water may increase the risk of kidney disease and cancer and has created a need for a quantified, scientific understanding of the occurrence and distribution of uranium isotopes in aquifers. The authors are investigating the occurrence of elevated uranium in northern Michigan aquifers of the Middle Proterozoic Jacobsville sandstone, a red to mottled sequence of sandstones, conglomerates, siltstones and shales deposited as basin fill in the 1.1 Ga Midcontinent rift. Approximately 25% of 300 well water samples tested for isotopic uranium have concentrations above the MCL. Elevated uranium occurrences are distributed throughout the Jacobsville sandstone aquifers stretching across Michigan's Upper Peninsula. However, there is significant variation in well water uranium concentrations (from 0.01 to 190 ppb) and neighboring wells do not necessarily have similar concentrations. The authors are investigating hydrogeologic controls on ground water uranium concentrations in the Jacobsville sandstone, e.g. variations in lithology, mineralogy, groundwater residence time and geochemistry. Approximately 2000' of Jacobsville core from the Amoco St. Amour well was examined in conjunction with the spectral gamma ray log run in the borehole. Spikes in equivalent uranium (eU) concentration from the log are frequently associated with clay and heavy mineral layers in the sandstone core. The lithology and mineralogy of these layers will be determined by analysis of thin sections and x-ray diffraction. A portable spectrometer, model GRS-2000/BL, will be used on the sandstone cliffs along Lake Superior to characterize depositional and lithologic facies of the Jacobsville sandstone in terms of concentrations and ratios of eU, eTh and K. Equipped with borehole accessories, the spectrometer will be used to log residential drinking wells to determine a relationship between the uranium concentration of well water and the eU concentration in the sandstone. Tritium/helium-3 dating will be used to determine whether ground water uranium concentrations increase with residence time. PHREEQCI will be used to model dominate aqueous species of uranium and saturation indices of uranium minerals.

Sherman, H.; Gierke, J.

2003-12-01

458

Hydrogeology of the Potsdam Sandstone in northern New York  

USGS Publications Warehouse

The Potsdam Sandstone of Cambrian age forms a transboundary aquifer that extends across northern New York and into southern Quebec. The Potsdam Sandstone is a gently dipping sequence of arkose, subarkose, and orthoquartzite that unconformably overlies Precambrian metamorphic bedrock. The Potsdam irregularly grades upward over a thickness of 450 m from a heterogeneous feldspathic and argillaceous rock to a homogeneous, quartz-rich and matrix-poor rock. The hydrogeological framework of the Potsdam Sandstone was investigated through an analysis of records from 1,500 wells and geophysical logs from 40 wells, and through compilation of GIS coverages of bedrock and surficial geology, examination of bedrock cores, and construction of hydrogeological sections. The upper several metres of the sandstone typically is weathered and fractured and, where saturated, readily transmits groundwater. Bedding-related fractures in the sandstone commonly form sub-horizontal flow zones of relatively high transmissivity. The vertical distribution of sub-horizontal flow zones is variable; spacings of less than 10 m are common. Transmissivity of individual flow zones may be more than 100 m2/d but typically is less than 10 m2/d. High angle fractures, including joints and faults, locally provide vertical hydraulic connection between flow zones. Hydraulic head gradients in the aquifer commonly are downward; a laterally extensive series of sub-horizontal flow zones serve as drains for the groundwater flow system. Vertical hydraulic head differences between shallow and deep flow zones range from 1 m to more than 20 m. The maximum head differences are in recharge areas upgradient from the area where the Chateauguay and Chazy Rivers, and their tributaries, have cut into till and bedrock. Till overlies the sandstone in much of the study area; its thickness is generally greatest in the western part, where it may exceed 50 m. A discontinuous belt of bedrock pavements stripped of glacial drift extends across the eastern part of the study area; the largest of these is Altona Flat Rock. Most recharge to the sandstone aquifer occurs in areas of thin, discontinuous till and exposed bedrock; little recharge occurs in areas where this unit is overlain by thick till and clay. Discharge from the sandstone aquifer provides stream and river baseflow and is the source of many springs. A series of springs that are used for municipal bottled water and fish-hatchery supply discharge from 1,000 to 5,000 L/min adjacent to several tributaries east of the Chateauguay River. The major recharge areas for the Chateauguay springs are probably upgradient to the southeast, where the till cover is thin or absent.

Williams, John H.; Reynolds, Richard J.; Franzi, David A.; Romanowicz, Edwin A.; Paillet, Frederick L.

2010-01-01

459

Material invariant properties and reconstruction of microstructure of sandstones by nanoindentation and microporoelastic analysis  

E-print Network

The diversity of sandstones and sandstone properties that exist in nature pose a significant problem for engineers who deal with these materials, whether in oil well exploration and exploitation or art and architectural ...

Bobko, Christopher Philip, 1981-

2005-01-01

460

Up-Scaling Geochemical Reaction Rates Accompanying Acidic CO2-Saturated Brine Flow in Sandstone Aquifers  

E-print Network

1 Up-Scaling Geochemical Reaction Rates Accompanying Acidic CO2-Saturated Brine Flow in Sandstone in the pore networks corresponding to three different sandstones. The simulations were used to study up

New York at Stoney Brook, State University of

461

Forebulge influence on deposition of the Cretaceous Castlegate Sandstone, Book Cliffs, Utah, U.S.A.  

E-print Network

Analysis of facies changes and paleocurrent directions of the incised valley fill of the Late Cretaceous Castlegate Sandstone supports a reinterpretation of the axis of the well-studied Castlegate Sandstone incised valley axis from an east...

Hoffmeister, Kathryn E.

2011-08-31

462

Depositional Setting, Facies, and Petroleum Geology of Boatwright Sandstones (Springer Group) in Parts of Caddo, Canadian, and Blaine Counties, OK.  

E-print Network

??Primary objectives of this study were to examine the depositional setting and establish sandstone facies, distribution, and petroleum geology for the Boatwright sandstones. Depositional setting… (more)

Chrisman, Jeremiah David

2009-01-01

463

Continuity and internal properties of Gulf Coast sandstones and their implications for geopressured fluid production  

SciTech Connect

The intrinsic properties of the genetic sandstone units that typify many geopressured geothermal aquifers and hydrocarbon reservoirs in the Gulf Coast region were systematically investigated classified, and differentiated. The following topics are coverd: structural and stratigraphic limits of sandstone reservoirs, characteristics and dimensions of Gulf Coast sandstones; fault-compartment areas; comparison of production and geologic estimates of aquifer fluid volume; geologic setting and reservoir characteristics, Wells of Opportunity; internal properties of sandstones; and implications for geopressured fluid production. (MHR)

Morton, R.A.; Ewing, T.E.; Tyler, N.

1983-01-01

464

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

465

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

466

Greybull Sandstone Petroleum Potential on the Crow Indian Reservation, South-Central Montana  

Microsoft Academic Search

The focus of this project was to explore for stratigraphic traps that may be present in valley-fill sandstone at the top of the Lower Cretaceous Kootenai Formation. This sandstone interval, generally known as the Greybull Sandstone, has been identified along the western edge of the reservation and is a known oil and gas reservoir in the surrounding region. The Greybull

David A

2002-01-01

467

Z .Chemical Geology 152 1998 227256 The thermal and cementation histories of a sandstone petroleum  

E-print Network

Z .Chemical Geology 152 1998 227­256 The thermal and cementation histories of a sandstone petroleum-feldspars recovered at various depths from a deep well drilled through a carbonate-cemented sandstone petroleum of a sandstone petroleum xreservoir, Elk Hills, California. Part 2: In situ oxygen and carbon isotopic results

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Shock reequilibration of fluid inclusions in Coconino sandstone from Meteor Crater, Arizona  

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Shock reequilibration of fluid inclusions in Coconino sandstone from Meteor Crater, Arizona Megan E sandstone were collected from Barringer Meteorite Crater (Meteor Crater, Arizona) and classified based of the Coconino sandstone at Meteor Crater, Arizona, Journal of Geophysical Research 76, 5449

Bodnar, Robert J.