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1

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

2

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

NASA Astrophysics Data System (ADS)

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

Bryant, Gerald; Monegato, Giovanni; Miall, Andrew

2013-11-01

3

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

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

4

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 the Lower Jurassic Navajo Sandstone of Arizona (UCMP locality V3308). In his original description, Camp

Hutchinson, John

5

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

NASA Astrophysics Data System (ADS)

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

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

2006-09-01

6

Synapsid Burrows in the Lower Jurassic Navajo Sandstone, Utah  

E-print Network

subhorizontal burrows found within fluvial deposits in Poland. FIGURE 44—Side and top view of Aardwolf burrows. Dotted line represents beginning of springhare burrows not modified by aardwolfs. Modified from Anderson and Richardson (2005). FIGURE 45—Plan map... from Begall and Gallardo (2000). FIGURE 49—Top and perspective view of white-tailed prairie dog burrows. Burrow was not completely excavated. Incompletely excavated tunnels are left open. Modified from Burns et al. (1989). xiv FIGURE 50—Plan...

Riese, David

2011-05-03

7

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

E-print Network

Disseminated `jigsaw piece' dolomite in Upper Jurassic shelf sandstones, Central North Sea textural and chemical characteristics of disseminated dolomite in Upper Jurassic shelf sediments, dolomite, isotopes, Jurassic, North Sea. 1 Present address: BG International Limited, Gas Research

Haszeldine, Stuart

8

Properties of Cotton Valley sandstone reservoirs (Upper Jurassic), Terryville Field, Lincoln Parish, Louisiana  

E-print Network

PROPERTIES OF COTTON VALLEY SANDSTONE RESERVOIRS (UPPER JURASSIC), TERRYVILLE FIELD, LINCOLN PARISH, LOUISIANA A Thesis by KAREN 'CELE MCBRIDE Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August 1982 Major Subject: Geology PROPERTIES OF COTTON VALLEY SANDSTONE RESERVOIRS (UPPER JURASSIC), TERRYVILLE FIELD, LINCOLN PARISH, LOUISIANA A Thesis by KAREN 'CELE MCBRIDE Approved as to style and content by...

McBride, Karen 'Cele

2012-06-07

9

Depositional environment of jurassic smackover sandstones, Thomasville field, Rankin County, Mississippi  

E-print Network

DEPOSITIONAL ENVIRONMENT OF JURASSIC SMACKOVER SANDSTONES, THOMASVILLE FIELD, RANKIN COUNTY, MISSISSIPPI A Thesis by REBECCA SARAH PENFIELD OLSEN Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE May 1980 Major Subject: Geology DEPOSITIONAL ENVIRONMENT OF JURASSIC SMACKOVER SANDSTONES, THOYiASVILLE FIELD, RANKIN COUNTY, MISSISSIPPI A Thesis by REBECCA SARAH PENFIELD OLSEN Approved as to style...

Olsen, Rebecca Sarah Penfield

2012-06-07

10

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

Microsoft Academic Search

Significant amounts of feldspar have been dissolved from Middle Jurassic sandstone oil reservoirs in the North Sea (northwest Europe) during burial diagenesis Sandstones of the Middle Jurassic Brent Group become increasingly quartzose with increasing burial depth. At Statfjord field (2500 m depth), sandstones are arkose to subarkose; at Hutton field (3050 m depth), they are subarkose to quartzarenite, and at

Nicholas B. Harris

1989-01-01

11

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

Microsoft Academic Search

Significant amounts of feldspar have been dissolved from Middle Jurassic sandstone oil reservoirs in the North Sea (northwest Europe) during burial diagenesis. Sandstones of the Middle Jurassic Brent Group become increasingly quartzose with increasing burial depth. At Stafford field (2500 m depth), sandstones are arkose to subarkose; at Hutton field (3050 m depth), they are subarkose to quartzarenite; and at

Nicholas B. Harris

1989-01-01

12

Geological Society of America Extensional arc setting and ages of Middle Jurassic eolianites,  

E-print Network

Jurassic eolianites, Cowhole Mountains (eastern Mojave Desert block, California) Cathy J. Busby Department indicate that the sandstone is Middle Jurassic and is therefore age equiv- alent to backarc eolianites of the Temple Cap and Carmel Formations, not the Lower Jurassic Navajo Formation as previously assumed. Our U

Busby, Cathy

13

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

14

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

15

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

16

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

17

Haynesville sandstone reservoirs in the Updip Jurassic trend of Alabama  

SciTech Connect

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

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

1994-09-01

18

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

19

Strength and failure characteristics of Jurassic Red-Bed sandstone under cyclic wetting-drying conditions  

NASA Astrophysics Data System (ADS)

Due to cyclic fluctuations of reservoir water levels, bank slopes in drawdown areas are subjected to wetting-drying cycles. In order to reasonably evaluate the stabilities of sandstone slopes in the drawdown area of the Three Gorges Reservoir, it is a primary premise to obtain the strength and failure characteristics of the sandstones undergoing wetting-drying cycles. In this paper, the conventional triaxial compression tests, ultrasonic velocity and porosity measurements and microstructural observations were conducted on Jurassic Red-Bed sandstone (JRS) specimens undergoing wetting-drying cycles. The results from the triaxial experiments indicate that the peak strengths of the JRS are dramatically reduced after the first wetting-drying cycle, and then remain approximately constant with increasing number of wetting-drying cycles. The failure modes of the JRS samples undergoing different wetting-drying cycles are all brittle failures under low confining pressures ( ? 15 MPa). The decrease in P-wave velocity and increase in porosity with increasing number of wetting-drying cycles reveals the raise of damage level of the sandstone specimens, which is the main reason for the decline of peak strength. Detailed microstructural analysis has shown obvious argillization phenomena after undergoing wetting-drying cycles, which weakens the cements between grains in the sandstone and increases the damage of the sandstone.

Zhang, Zhenhua; Jiang, Qinghui; Zhou, Chuangbing; Liu, Xinting

2014-08-01

20

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

21

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

SciTech Connect

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

Harris, N.B. (Conoco Inc., Ponca City, OK (USA))

1989-04-01

22

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

NASA Astrophysics Data System (ADS)

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

Harris, Nicholas B.

1989-04-01

23

Synfolding magnetization in the Jurassic Preuss Sandstone, Wyoming- Idaho-Utah thrust belt  

USGS Publications Warehouse

The Jurassic Preuss Sandstone, exposed in five thrust plates of the Wyoming-Idaho-Utah thrust belt, carried directions of remanent magnetization that group most tightly after only partial unfolding. Field, petrographic, and rock magnetic evidence indicates that the carrier of this magnetization is detrital, low-Ti titanomagnetite. The detrital titanomagnetite was remagnetized at low temperatures (75??-150??C) probably completely during folding. Anisotropy of magnetic susceptibility and petrographic observations indicate that the detrital titanomagnetite has been affected by tectonic strain. The locus of acquisition of synfolding magnetization in the Preuss migrated in conjunction with deformation in the thrust belt. A model is presented in which synfolding magnetization was acquired during cooling and folding as strata moved up thrust ramps. A lack of reverse-polarity directions remains a puzzling feature of the remanence. -from Authors

Hudson, M. R.; Reynolds, R. L.; Fishman, N. S.

1989-01-01

24

The Jurassic section along McElmo Canyon in southwestern Colorado  

USGS Publications Warehouse

In McElmo Canyon, Jurassic rocks are 1500-1600 ft thick. Lower Jurassic rocks of the Glen Canyon Group include (in ascending order) Wingate Sandstone, Kayenta Formation and Navajo Sandstone. Middle Jurassic rocks are represented by the San Rafael Group, which includes the Entrada Sandstone and overlying Wanakah Formation. Upper Jurassic rocks comprise the Junction Creek Sandstone overlain by the Morrison Formation. The Burro Canyon Formation, generally considered to be Lower Cretaceous, may be Late Jurassic in the McElmo Canyon area and is discussed with the Jurassic. The Upper Triassic Chinle Formation in the subsurface underlies, and the Upper Cretaceous Dakota Sandstone overlies, the Jurassic section. An unconformity is present at the base of the Glen Canyon Group (J-0), at the base of the San Rafael Group (J-2), and at the base of the Junction Creek Sandstone (J-5). Another unconformity of Cretaceous age is at the base of the Dakota Sandstone. Most of the Jurassic rocks consist of fluviatile, lacustrine and eolian deposits. The basal part of the Entrada Sandstone and the Wanakah Formation may be of marginal marine origin.

O'Sullivan, Robert B.

1997-01-01

25

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

SciTech Connect

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

Havholm, K.G.; Kocurek, G. (Univ. of Texas, Austin (United States))

1991-03-01

26

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... in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE May 1983 Major Subject: Geology ENVIROf'iI'1ENT OF DEPOSITION AND RESFRVOIR FACIES OF THE TAYLOR "8" SANDSTONE, COTTON VALLEY GROUP (UPPER JURASSIC), KILDARE FIFLD, CASS...

Black, Cynthia England

2012-06-07

27

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

28

Sedimentation of the Triassic–Jurassic Adigrat Sandstone Formation, Blue Nile (Abay) Basin, Ethiopia  

Microsoft Academic Search

Exploration of oil and gas deposits in the Blue Nile Basin targeted the Adigrat Sandstone Formation as a reservoir objective. Conglomerates, gravely sandstones, coarse to medium-grained sandstones, very fine-grained cross-bedded sandstones, siltstones and mudstones of the Adigrat Sandstone Formation were deposited in semi-arid to arid climates. The North-western highlands are the main source for the sedimentation. The poorly-sorted, crudely-bedded conglomerates

A. Wolela

2008-01-01

29

Sedimentation of the Triassic Jurassic Adigrat Sandstone Formation, Blue Nile (Abay) Basin, Ethiopia  

NASA Astrophysics Data System (ADS)

Exploration of oil and gas deposits in the Blue Nile Basin targeted the Adigrat Sandstone Formation as a reservoir objective. Conglomerates, gravely sandstones, coarse to medium-grained sandstones, very fine-grained cross-bedded sandstones, siltstones and mudstones of the Adigrat Sandstone Formation were deposited in semi-arid to arid climates. The North-western highlands are the main source for the sedimentation. The poorly-sorted, crudely-bedded conglomerates and gravely sandstones are interpreted as alluvial fan deposits. The basal polymictic orthoconglomerate passes up vertically into gravely sandstone, possibly indicating proximal to mid-fan sedimentation. The alluvial fan sedimentation passes up vertically into channel, point bars and flood-plain fines. The meandering river sedimentation is characterized by single and amalgamated multi-storey sandstone bodies. In places, the uppermost part of the Adigrat Sandstone Formation is represented by coal-bearing sediments possibly reflect lacustrine depositional environment. The medium-coarse-grained sandstone is a possible oil and gas reservoir, whilst the fine-grained sediments are a possible gas reservoir.

Wolela, A.

2008-09-01

30

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

E-print Network

bedsets. 12513 ft. D. Facies 2, laminated siltstones and shales. DE bedsets. 12515. 3 ft. Facies 1, massive sandstone of A bed; discontinuous concave upwards "dish" structures are water escape features of rapidly deposited bed. 12524 ft. Facies 1... bedsets. 12513 ft. D. Facies 2, laminated siltstones and shales. DE bedsets. 12515. 3 ft. Facies 1, massive sandstone of A bed; discontinuous concave upwards "dish" structures are water escape features of rapidly deposited bed. 12524 ft. Facies 1...

Mani, Philip Charles

2012-06-07

31

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

32

Haynesville sandstone reservoirs in the updip-Jurassic trend of Alabama  

SciTech Connect

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

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

1994-12-31

33

Navajo Nation  

NSDL National Science Digital Library

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

Ellie, Crystal; Crystalinks

34

Navajo Timeline  

NSDL National Science Digital Library

This searchable timeline describes Navajo history from 1200 BC through the year 2002. Throughout the timeline, historical events of the Navajo are described and paired with world history. Useful links to topics concerning the Navajo can be found in the later periods within the timeline. Users can search the timeline using a pull-down menu of time periods.

Harrison, Lapahie

35

Navajo Indians  

NSDL National Science Digital Library

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

Chamberlain, Keshia

2009-11-28

36

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

37

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

NASA Astrophysics Data System (ADS)

South Africa has a wealth of sandstone landforms, yet many of these have not been examined in detail to expand knowledge on their morphology and process origins. Here we present data on primary morphological statistics, rock hardness, surface roughness and petrographic investigations of rock doughnuts and associated pothole structures in Golden Gate Highlands National Park (GGHNP) and in the Witkop III complex, with the aim of using such data and field observations to argue their likely origins. Schmidt hammer R-values indicate consistently harder doughnut rims (mean = 48.7; n = 150) than the enclosed potholes (mean = 37.8; n = 150) and surrounding sandstone platform (mean = 39.7; n = 250). The petrography of Clarens Fm. Sandstone shows that the typical whitish sandstone is affected by intense chemical weathering. Pothole rims and the irregular reddish crust typical of the Witkop III outcrops show a secondary cementation by microcrystalline silica. Although preservation of old land surfaces is difficult to prove, small and circular pipe structures filled with calcite-cemented sand are present locally surrounding the Witkop III hydrothermal complex, and represent conduits for fluidized sand. Based on the morphologies of the Witkop III summit with the associated potholes and pipes, we hypothesize that they are remnants of morphologies created by Jurassic fluid seepage, with a superimposed and secondary silica cementation. Given that fluidization structures evidently occur in Clarens Fm. Sandstone, as is the case at Witkop, such mechanisms could possibly have contributed to the observed rock doughnut structures elsewhere on Clarens Fm. Sandstones, such as at the GGHNP where the rock doughnut morphological attributes are typical to landforms originating from fluid venting.

Grab, Stefan; Svensen, Henrik

2011-08-01

38

Navajo Country  

NSDL National Science Digital Library

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

Harrison, Lapahie

39

Navajo Arts and Crafts.  

ERIC Educational Resources Information Center

A profusely-illustrated book on Navajo arts and crafts, from the Navajo Curriculum Center, includes sections on weaving, silversmithing, basket making, pottery making, and the economics of Navajo arts and crafts. The book is intended for use by Navajo students and Navajo people in general, so they can read about their arts and crafts from a Navajo…

Roessel, Robert A., Jr.

40

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

41

Navajo Studies at Navajo Community College.  

ERIC Educational Resources Information Center

The document covers the Navajo Studies Program (NSP) at Navajo Community College (NCC). The Navajo Studies Program differs from other Indian Studies Programs in 7 ways, e.g.: (1) it is located on the Navajo Reservation and controlled by the tribe; (2) NCC incorporates Indian studies into every individual program and area of concentration--English…

Hatathli, Ned

42

Conversational Navajo  

NSDL National Science Digital Library

Most of the Din4 (Navajo) students now entering Kindergarten do not speak the Din4 language. And with the majority of parents wanting Din4 language classes for their children, this program was put together. This is also a School Board and Bilingual Education Consensus Committee mandate.

District, San J.

43

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

44

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

45

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

. Schmidt hammer R-values indicate consistently harder doughnut rims (mean=48.7; n=150) than the enclosed, geomorphologists have placed emphasis on understanding contemporary micro- spatio-temporal scales of sandstone

Svensen, Henrik

46

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

47

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.

48

Navajo Wisdom and Traditions.  

ERIC Educational Resources Information Center

The oral literature of the Navajo people generally falls into two categories: the sacred stories and the folk tales, which often, but not always, point a moral. Sacred stories relate the Navajo's emergence history. These stories tell how the universe holds two kinds of people: the "Earth Surface People" (both living and dead) and the "Holy People"…

Yazzie, Ethelou

49

Navajo Education and the Future.  

ERIC Educational Resources Information Center

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

Roessel, Robert A., Jr.

1999-01-01

50

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

51

Protection of Navajo Sacred Objects  

E-print Network

Background: US-Navajo History 9 Chapter 2 How Culture Leaves the Navajo 28 Chapter 3 Conflicts in Ownership 44 Chapter 4 Proposed Codes 56 Conclusion 65 3 I grew up on Navajo land near a... of personal direct observation, and secondary and primary sources. The first chapter reviews the history of the Navajo - United States relationship and shows how US polices altered the Navajo people from a position of self-efficiency to one of dependency...

Yazzie, Elerina

2008-07-31

52

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

53

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

Microsoft Academic Search

We report an investigation of faults in porous sedimentary rocks subjected to high strain rates. We focused on lower-displacement faults cutting Navajo Sandstone within the ring syncline of Upheaval Dome impact structure in Canyonlands National Park, Utah, where high strain rate conditions are known to have occurred. Results of our field investigation revealed grains within the Navajo Sandstone were pulverized

W. R. Orr; R. A. Schultz

2008-01-01

54

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.

55

Navajo Reflections on Climate Change  

NSDL National Science Digital Library

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

Foundation, Wgbh E.

2012-03-23

56

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

57

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

ERIC Educational Resources Information Center

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

House, Deborah

1997-01-01

58

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

59

Analysis of Navajo Education Authority.  

ERIC Educational Resources Information Center

The legislative authority for Navajo education is examined in this two-part report, designed to help the Navajo people attain meaningful control of the education of their youth, with the continued appropriate involvement of the federal and state governments. Part 1 summarizes the key provisions of the relevant sources of legal authority which…

Kahn & Kahn, Washington, DC.

60

Navajo Nation Educational Hearings, 1975.  

ERIC Educational Resources Information Center

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

Navajo Tribe, Window Rock, AZ.

61

The Navajos, A Critical Bibliography.  

ERIC Educational Resources Information Center

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

Iverson, Peter

62

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.

63

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

64

Marine Jurassic lithostratigraphy of Thailand  

NASA Astrophysics Data System (ADS)

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

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

65

Navajo Rug with English Voice  

NSDL National Science Digital Library

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

Edgmon, Jeneen

2011-01-01

66

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

ERIC Educational Resources Information Center

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

Holm, Wayne; Silentman, Irene; Wallace, Laura

67

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

Microsoft Academic Search

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

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

2002-01-01

68

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

69

Navajo History: The Land and the People.  

ERIC Educational Resources Information Center

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

Acrey, Bill P.

70

Compensation of Navajo Uranium Miners  

NSDL National Science Digital Library

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

Project, World I.

71

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

72

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

73

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.

74

Mortality among Navajo uranium miners.  

PubMed Central

OBJECTIVES. To update mortality risks for Navajo uranium miners, a retrospective cohort mortality study was conducted of 757 Navajos from the cohort of Colorado Plateau uranium miners. METHODS. Vital status was followed from 1960 to 1990. Standardized mortality ratios were estimated, with combined New Mexico and Arizona non-White mortality rates used for comparison. Cox regression models were used to evaluate exposure-response relationships. RESULTS. Elevated standardized mortality ratios were found for lung cancer (3.3), tuberculosis (2.6), and pneumoconioses and other respiratory diseases (2.6). Lowered ratios were found for heart disease (0.6), circulatory disease (0.4), and liver cirrhosis (0.5). The estimated relative risk for a 5-year duration of exposure vs none was 3.7 for lung cancer, 2.1 for pneumoconioses and other respiratory diseases, and 2.0 for tuberculosis. The relative risk for lung cancer was 6.9 for the midrange of cumulative exposure to radon progeny compared with the least exposed. CONCLUSIONS. Findings were consistent with those from previous studies. Twenty-three years after their last exposure to radon progeny, these light-smoking Navajo miners continue to face excess mortality risks from lung cancer and pneumoconioses and other respiratory diseases. PMID:7702118

Roscoe, R J; Deddens, J A; Salvan, A; Schnorr, T M

1995-01-01

75

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

76

The formation of conjugate normal fault systems in folded sandstone by sequential jointing and shearing, Waterpocket monocline, Utah  

NASA Astrophysics Data System (ADS)

We report conjugate normal fault development by the formation and subsequent shearing of joints during flexure and associated extension of the Jurassic Wingate and Navajo Sandstones at the core of the Waterpocket monocline, Utah. Geometry and structural components across fault zones were quantified from an incipient stage to a relatively well-developed stage where the zone is 120 m wide and accommodates more than 3.5 m of slip. Shearing of joints leads to the formation of splay fractures near the joints' tip. Subsequently, these splay fractures are sheared and a new generation of splay fractures forms. Multiple generations of splay fractures cause the width of the fault damage zone to expand into the surrounding host rock, producing unusually wide fault damage zones with respect to fault offset. These extensive fault damage zones are stratigraphically confined and develop with low strains at small bed dips during folding. The faults formed by this sequential process develop a characteristic fault architecture distinguished by the type of component structures, their geometric relationships, and their distribution. We conclude that cyclic joint formation, shearing accompanied by splay fracture formation, and repeated shearing produce a geometric pattern similar to a classical conjugate fault system. However, the mechanism identified here has different implications for fault intersection angles, stress inversion, and fault architecture.

Davatzes, Nicholas C.; Aydin, Atilla

2003-10-01

77

An Ethnography of the Navajo Reproductive Cycle.  

ERIC Educational Resources Information Center

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

Wright, Anne

1982-01-01

78

"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.

79

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.

80

Sovereignty: The Navajo Nation and Taxation.  

ERIC Educational Resources Information Center

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

Benson, Michael

81

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

82

Final Report - Navajo Electrification Demonstration Project - FY2004  

SciTech Connect

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

Kenneth L. Craig, Interim General Manager

2007-03-31

83

Final Report Navajo Transmission Project (NTP)  

SciTech Connect

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

Bennie Hoisington; Steven Begay

2006-09-14

84

CASE CRITICAL The Navajo Generating Station  

E-print Network

Republic The Navajo Generating Station, the largest coal-fired power plant in the West, provides electrical-old plant, Arizona's largest single source of carbon pollution, needs to update its pollution controls. Join

Hall, Sharon J.

85

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

ERIC Educational Resources Information Center

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

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

86

and Early Jurassic sediments, and  

E-print Network

and Early Jurassic sediments, and patterns of the Triassic-Jurassic PAUL E. OLSEN AND tetrapod transition HANS-DIETER SUES Introduction The Late Triassic-Early Jurassic boundary is fre- quently cited to other terrestrial and extraterrestrial phenomena (see Chapter 24). The Triassic-Jurassic boundary takes

Olsen, Paul E.

87

Jurassic accretion tectonics of Japan  

Microsoft Academic Search

The Jurassic accretionary complex and coeval granites in Japan represent remnants of the Jurassic arc-trench system developed between the Asian continent and Pacific Ocean. The Jurassic accretionary complex occurs as a large-scale nappe that is tectonically sandwiched be- tween the overlying pre-Jurassic nappes and underlying post-Jurassic nappes. By virtue of new research styles (microfossil mapping and chronometric mapping) the following

Yukio Isozaki

1997-01-01

88

The Navajo Uranium Mining Experience, 2003-1952  

NSDL National Science Digital Library

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

Shuey, Chris; Center, Southwest R.

89

Jurassic Park Safety Audit  

NSDL National Science Digital Library

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

2007-09-18

90

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

ERIC Educational Resources Information Center

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

Atcitty, Thomas E.

91

Nursing Care and Beliefs of Expectant Navajo Women (Part 2).  

ERIC Educational Resources Information Center

Based on premise that people are more receptive to nursing care that is in harmony with their own cultural outlook on health. Identifies cultural needs and beliefs of 191 pregnant Navajo women. Finds key indicators separating transitional from traditional Navajo are not same as indicators separating transitional from modern Navajos. (NEC)

Milligan, B. Carol

1984-01-01

92

Health Problems of the Navajo Area and Suggested Interventions.  

ERIC Educational Resources Information Center

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

Kaltenbach, Charles

93

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.

94

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.

Leinfelder, Reinhold

95

Jurassic Reef Park  

NSDL National Science Digital Library

Dr. Reinhold Leinfelder of the University of Stuttgart, Germany created this interesting site in English and German, offering a "virtual trip to the reefs of the Jurassic Period." In the Introduction, viewers will find background material and comparisons of modern and ancient reefs. Further information is provided in the sections on reef architecture, reef formation, Jurassic reefs, and reefs and global climate change. Although the English language is slightly quirky, the content and images more than compensate, making this a worthwhile site.

96

Jurassic conchostracans from Patagonia  

E-print Network

THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS September 16, 1970 Paper 50 JURASSIC CONCHOSTRACANS FROM PATAGONIA PAUL TASCH 1 and WOLFGANG VOLKHEIMER2 I Department of Geology, Wichita State University, Wichita, Kansas, Muse° A rgentino de... Ciencias Naturides "Bernar- dino Rivadavia," Buenos Aires, Argentina PART 1. PALEONTOLOGY AND PALEOECOLOGY PAUL TASCH ABSTRACT Two new species ( and three others) of the conchostracan genus Cyzicus are described and figured. All are Jurassic (Callovian...

Tasch, P.; Volkheimer, W.

1970-09-16

97

Diagnosis and distress in Navajo healing.  

PubMed

In contemporary Navajo society, traditional Navajo ceremonies, Native American Church prayer meetings, and Navajo Christian faith healing are all highly sought-after resources in the everyday pursuit of health and well-being. What is the nature of affliction among patients who turn to such forms of religious healing? Are these patients typically afflicted with psychiatric disorder? In this article we discuss 84 Navajo patients who participated in the Navajo Healing Project during a period in which they consulted one of these forms of healing. We present diagnostic results obtained from the Structured Clinical Interview for DSMIV (SCID) administered to these patients. We then present an ethnographically augmented analysis comparing the research diagnosis obtained via the SCID with a clinical diagnosis, with the diagnosis given by religious healers, and with the understanding of their own distress on the part of patients. These analyses demonstrate how a cultural approach contributes to the basic science and clinical understandings of affliction as well as to discussion of the advantages and limitations of DSM categories as descriptors of distress and disorder. PMID:18974670

Csordas, Thomas J; Storck, Michael J; Strauss, Milton

2008-08-01

98

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

Microsoft Academic Search

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

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

99

Haynesville sandstone reservoirs in the Updip Jurassic trend of Alabama  

Microsoft Academic Search

Subsequent to the 1986 drilling of the 1 Carolyn McCollough Unit 1-13 well, which initiated production from the Frisco City sand of the Haynesville Formation in Monroe County, Alabama, seven Haynesville fields have been established in Covington, Escambia, and Monroe counties. Initial flow rates of several hundred BOPD are typical for wells in these fields, and maximum rates exceed 2000

R. L. Kugler; R. M. Mink

1994-01-01

100

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

ERIC Educational Resources Information Center

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

Cordova, Dahlia

101

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

ERIC Educational Resources Information Center

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

Lee, Lloyd L.

2008-01-01

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

Navajo National Monument: An Archaeological Assessment.  

National Technical Information Service (NTIS)

The report presents a summary of information on all three tracts of land and the cultural resources contained in Navajo National Monument. The monument consists of 360 acres in parcels surrounding the 13th century Kayenta Anasazi cliff villages of Kiet Si...

J. R. Ambler

1985-01-01

104

Harlequin Ichthyosis among the Navajo: Counseling issues  

Microsoft Academic Search

Harlequin Ichthyosis is a rare, fatal congenital disorder of keratinization characterized by thickened, scale-like plaques of skin with a diamond configuration. Autosomal recessive inheritance has been established, and prenatal diagnosis for this disorder remains controversial. Five infants with this disorder were born among approximately 25,000 Navajo women who delivered in Gallup, New Mexico from 1970 to 1989. The incidence of

Patricia N. Olney; Richard S. Olney

1993-01-01

105

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

106

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

...Approval of the Navajo Nation's abandoned mine land plan. 756.13 Section 756...LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.13 Approval of the Navajo Nation's abandoned mine land plan. The Navajo Nation's...

2014-07-01

107

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

Code of Federal Regulations, 2010 CFR

...false When may a permittee commence grazing on Navajo Partitioned Land? 161...AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.307 When may a permittee commence grazing on Navajo Partitioned Land?...

2010-04-01

108

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

Federal Register 2010, 2011, 2012, 2013

...Collection for Navajo Partitioned Lands Grazing Permits AGENCY: Bureau of Indian Affairs...information for Navajo Partitioned Lands Grazing Permits authorized by OMB Control Number...applicant to obtain, modify, or assign a grazing permit on Navajo Partitioned Lands...

2013-05-29

109

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

Code of Federal Regulations, 2011 CFR

...false When may a permittee commence grazing on Navajo Partitioned Land? 161...AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.307 When may a permittee commence grazing on Navajo Partitioned Land?...

2011-04-01

110

78 FR 15036 - Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing Permits  

Federal Register 2010, 2011, 2012, 2013

...Collection for Navajo Partitioned Lands Grazing Permits AGENCY: Bureau of Indian Affairs...information for Navajo Partitioned Lands Grazing Permits authorized by OMB Control Number...applicant to obtain, modify, or assign a grazing permit on Navajo Partitioned Lands...

2013-03-08

111

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

Code of Federal Regulations, 2012 CFR

...true When may a permittee commence grazing on Navajo Partitioned Land? 161...AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.307 When may a permittee commence grazing on Navajo Partitioned Land?...

2012-04-01

112

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

...false When may a permittee commence grazing on Navajo Partitioned Land? 161...AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.307 When may a permittee commence grazing on Navajo Partitioned Land?...

2014-04-01

113

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

Code of Federal Regulations, 2013 CFR

...false When may a permittee commence grazing on Navajo Partitioned Land? 161...AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.307 When may a permittee commence grazing on Navajo Partitioned Land?...

2013-04-01

114

Exploring Jurassic Park.  

ERIC Educational Resources Information Center

Describes several student-tested activities built around "Jurassic Park." The activities feature students engaged in role-playing scenarios, investigative research projects, journal writing and communications skills activities, cooperative learning groups, and learning experiences that make use of reading skills and mathematical knowledge. (PR)

Simmons, Patricia E.; Wiley, Clyde

1993-01-01

115

Stabilization of friable sandstone surfaces in a desiccating, wind-abraded environment of south-central Utah by rock surface microorganisms  

Microsoft Academic Search

Wind abrasion has resulted in a number of interesting geologic features on the Colorado Plateau. Among these features is a wind-abraded groove and associated weathering pit located in south-central Utah. The groove has formed on the Navajo Sandstone which is friable and erodible due to the sparse interstitial clay and silica that cements the grains of quartz and feldspar. Examination

Harry D. Kurtz; Dennis I. Netoff

2001-01-01

116

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

SciTech Connect

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

Libby-French, J.

1984-12-01

117

Reservoir Characterization, Formation Evaluation, and 3D Geologic Modeling of the Upper Jurassic Smackover Microbial Carbonate Reservoir and Associated Reservoir Facies at Little Cedar Creek Field, Northeastern Gulf of Mexico  

E-print Network

reservoirs are microbial carbonate facies and associated nearshore high energy shoal facies of the Upper Jurassic Smackover Formation that overlie conglomerate and sandstone facies of the Norphlet Formation and underlie the argillaceous, anhydritic...

Al Haddad, Sharbel

2012-10-19

118

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

USGS Publications Warehouse

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

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

2006-01-01

119

Diagenetic pathways for sandstones: The role of initial composition  

SciTech Connect

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

Harris, N.B. [Pennsylvania State Univ., University Park, PA (United States)

1995-09-01

120

1, 119, 2006 Jurassic seasons  

E-print Network

eED 1, 1­19, 2006 Jurassic seasons C. L´ecuyer and H. Bucher Title Page Abstract Introduction reviewed discussion forum of eEarth Stable isotope compositions of a late Jurassic ammonite shell: a record Correspondence to: C. L´ecuyer (clecuyer@univ-lyon1.fr) 1 #12;eED 1, 1­19, 2006 Jurassic seasons C. L

Paris-Sud XI, Université de

121

Social Interaction Patterns and Relative Urban Success: the Denver Navajo  

ERIC Educational Resources Information Center

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

Snyder, Peter Z.

1973-01-01

122

Navajo Uranium Education Programs: The Search for Environmental Justice  

Microsoft Academic Search

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 initially had no vocabulary to understand the nature of

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

2004-01-01

123

Demographic and epidemiologic transition among the Navajo Indians  

Microsoft Academic Search

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

David W. Broudy; Philip A. May

1983-01-01

124

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

125

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

126

"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

127

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

128

Right after Sundown: Teaching Stories of the Navajos.  

ERIC Educational Resources Information Center

Understanding of the traditional Navajo world view and philosophy is ultimately centered on their origin story of emergence into the present world. All stories stem from this basic one. This collection of 12 Navajo stories includes origin stories, coyote stories, and a fairly recent one that describes a recognizable place. In the Anglo sense,…

Mabery, Marilyne Virginia

129

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

ERIC Educational Resources Information Center

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

Wilson, Alan; Dennison, Gene

130

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

131

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

132

Report on the First Conference on Navajo Orthography: Albuquerque, New Mexico, May 2-3, 1969.  

ERIC Educational Resources Information Center

At the first Conference on Navajo Orthography held in Albuquerque, New Mexico, in 1969, participants agreed upon a uniform orthography for Navajo developed by William Morgan and Robert Young and recommended development of a Navajo adult literacy program. Participants included representatives of the Bureau of Indian Affairs, Navajo Tribal Council…

Ohannessian, Sirarpi

1996-01-01

133

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

ERIC Educational Resources Information Center

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

Fowler, Henry H.

2010-01-01

134

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

135

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

136

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

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

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

139

Jurassic Park: Adventure in Learning.  

ERIC Educational Resources Information Center

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

Shams, Marcia; Boteler, Trina

1993-01-01

140

The Science Behind Jurassic Park  

NSDL National Science Digital Library

"The Science Behind Jurassic Park" is an html document describing how world renowned paleontologist Jack Horner is using computers and CAT scan machines to peer inside 30 million year old dinosaur fossils.

141

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 ...

142

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

143

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

144

Compactional deformation bands in Wingate Sandstone; additional evidence of an impact origin for Upheaval Dome, Utah  

NASA Astrophysics Data System (ADS)

Field and microstructural observations from Upheaval Dome, in Canyonlands National Park, Utah, show that inelastic strain of the Wingate Sandstone is localized along compactional deformation bands. These bands are tabular discontinuities (< 0.5 cm thick) that accommodate inelastic shear and compaction of inter-granular volume. Measurements of porosity and grain size from non-deformed samples are used to define a set of capped strength envelopes for the Wingate Sandstone. These strength envelopes reveal that compactional deformation bands require at least ca. 0.7 GPa (and potentially more than 2.3 GPa) of effective mean stress in order to nucleate within this sandstone. We find that the most plausible geologic process capable of generating these required magnitudes of mean stress is a meteoritic impact. Therefore the compactional deformation bands observed within the Wingate Sandstone are additional evidence of an impact event at Upheaval Dome and support a post-Wingate (post-Early Jurassic) age for this impact.

Okubo, Chris H.; Schultz, Richard A.

2007-04-01

145

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

146

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 the possibility of its wide occurrence in geological systems. Rate laws and proposed mechanisms should consider

Zhu, Chen

147

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

Microsoft Academic Search

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

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

1999-01-01

148

Frisco City sand: New Jurassic reservoir in southwest Alabama  

SciTech Connect

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

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

1989-09-01

149

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

...amendments to the Navajo Nation's abandoned mine land plan. 756.15 Section 756...LANDS PROGRAM INDIAN TRIBE ABANDONED MINE LAND RECLAMATION PROGRAMS § 756.15...amendments to the Navajo Nation's abandoned mine land plan. Pursuant to 30...

2014-07-01

150

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

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

2014-07-01

151

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

Code of Federal Regulations, 2010 CFR

...3400 Navajo Indian lands—Class II wells. The UIC program for Class II injection wells located: Within the exterior boundaries...UIC program under the SDWA for Class II injection wells on Navajo Indian lands for...

2010-07-01

152

75 FR 16174 - Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing Permits; Request...  

Federal Register 2010, 2011, 2012, 2013

...Collection for Navajo Partitioned Lands Grazing Permits; Request for Comments AGENCY...titled ``Navajo Partitioned Lands Grazing Permits, 25 CFR 161'' to the Office...order to obtain, modify, or assign a grazing permit. DATES: Interested persons...

2010-03-31

153

75 FR 4410 - Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing Regulations Permits  

Federal Register 2010, 2011, 2012, 2013

...Collection for Navajo Partitioned Lands Grazing Regulations Permits AGENCY: Bureau of...titled ``Navajo Partitioned Lands Grazing Regulations Permits, 25 CFR 161'' to...order to obtain, modify, or assign a grazing permit. DATES: Interested persons...

2010-01-27

154

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

ERIC Educational Resources Information Center

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

Federal Trade Commission, Los Angeles, CA.

155

The Feasibility of Test Translation between Unrelated Languages: English to Navajo  

ERIC Educational Resources Information Center

The Boehm Test of Basic Concepts was translated into Navajo to investigate whether an English test can be translated into Navajo in a form suitable for assessing the language development of K-2 level Navajos. Differences were in: syntactic difficulty, organization of experience into concepts, accidental similarity of words, ranges of meaning. (SCC)

Rosenbluth, Annabelle R.

1976-01-01

156

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

ERIC Educational Resources Information Center

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

Lipps, Oscar H.

157

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

158

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

159

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

160

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

161

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

SciTech Connect

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

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

1993-01-01

162

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

163

Trace fossils from Jurassic lacustrine turbidites of the anyao formation (Central China) and their environmental and evolutionary significance  

Microsoft Academic Search

The Lower Jurassic Anyao Formation crops out near Jiyuan city, western Henan Province, central China. It is part of the infill of the nonmarine early Mesozoic Jiyuan?Yima Basin. In the Jiyuan section, this unit is about 100 m thick and consists of laterally persistent, thin and thick?bedded turbidite sandstones and mudstones displaying complete and base?or top?absent Bouma sequences, and thick?bedded

Luis Alberto Buatois; Maria Gabriela Mângano; Xiantao Wu; Guocheng Zhang

1996-01-01

164

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

165

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

166

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.

167

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

168

Depth and thickness of selected units in Upper Permian, Upper Jurassic, and Lower Cretaceous rocks in southwestern Kansas  

USGS Publications Warehouse

As ground-water reserves decline in the Ogallala aquifer in an area of about 17,400 square miles in 26 counties of southwestern Kansas, sandstone aquifers in underlying Upper Jurassic and Lower and Upper Cretaceous rocks may be developed to supplement or replace the Ogallala as a source of water for some uses. Maps show that depths from land surface to Upper Permian rocks range from 0 at the outcrop to over 2,100 feet, depths to Upper Jurassic rocks ran from 0 at the outcrop to about 2,000 feet, depths to the Cheyenne Sandstone range from about 150 to about 1 ,950 feet, and depths to the Dakota Formation range from 0 at the outcrop to about 1,650 feet. Additional maps show that the thickness of Upper Jurassic rocks, where present, ranges from less than 50 feet to about 250 feet, the thickness of the Cheyenne Sandstone, where present, ranges from about 20 feet to about 250 feet, and the thickness of the Dakota Formation, where present, ranges from about 60 feet to about 460 feet. (USGS)

Kume, Jack; Spinazola Joseph M.

1984-01-01

169

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

170

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

171

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

172

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 magmatism. Princi- pal types of Jurassic mineralized systems include: (1) porphyry, skarn, replacement

Barton, Mark D.

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

Presence of the dinosaur Scelidosaurus indicates Jurassic age for the Kayenta Formation (Glen Canyon Group, northern Arizona)  

NASA Astrophysics Data System (ADS)

The Glen Canyon Group (Moenave, Wingate, Kayenta and Navajo Formations) of northern Arizona represents an extensive outcrop of early Mesozoic age terrestrial sediments. The age of these formations has long been disputed because independent stratigraphic data from marine tie-ins, paleobotanical and palynological evidence, and radiometric calibrations have been scanty or absent. The fauna of the Kayenta Formation in particular has been problematic because it has appeared to contain both typical Late Triassic and Early Jurassic taxa Here I report that the principal evidence for Late Triassic taxa, dermal scutes previously assigned to an aetosaur, in fact belongs to the thyreophoran ornithischian dinosaur Scelidosaurus, previously known only as a washed-in form found in marine sediments in the Early Jurassic of England. The presence of this dinosaur represents the first vertebrate biostratigraphic tie-in of the Glen Canyon Group horizons with reliably dated marine deposits in Europe. Together with revised systematic assessments of other vertebrates and independent evidence from fossil pollen, it supports an Early Jurassic age for the Kayenta Formation and most or all of the Glen Canyon Group.

Padian, Kevin

1989-05-01

175

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

USGS Publications Warehouse

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

Hart, Robert J.; Fisk, Gregory G.

2014-01-01

176

Jurassic Park Institute: Dino Lab  

NSDL National Science Digital Library

Created as a "science-based and educationally focused program," the Jurassic Park Institute (JPI) aims to provide "kids, families, educators and scientists with the ultimate resource for dinosaur learning and fun." As would be expected from a project of Universal Studios, the JPI Dino Lab Web site is packed with cool computer animation and other multimedia features. Visitors to this site become virtual dinosaur paleontologists, interpreting discoveries and solving problems along the way. Educators can register for JPI Dino Lab's free Teacher Resources, which includes lesson plans, assessment tools, and teaching strategy tips. This site is best accessed with a high-speed connection.

177

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

178

Jurassic platform development, northwestern Gulf of Mexico  

Microsoft Academic Search

Triassic and Early Jurassic rifting set the stage for the subsequent development of carbonate platforms in the Late Jurassic. These platforms formed along the interior margins of salt basins separated from the main ancestral Gulf of Mexico by a series of positive features. A major sea level rise, after deposition of the Louann Salt (late Callovian), drowned the interior salt

C. H. Jr

1987-01-01

179

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

180

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

181

A gestural account of the velar fricative in Navajo  

PubMed Central

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

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

2013-01-01

182

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

183

Strategies for assessing EarlyMiddle (PliensbachianAalenian) Jurassic  

E-print Network

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

184

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

185

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

186

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

Code of Federal Regulations, 2012 CFR

...are required that tribal laws apply to grazing permits on the Navajo Partitioned Lands...LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining...are required that tribal laws apply to grazing permits on the Navajo Partitioned...

2012-04-01

187

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

Code of Federal Regulations, 2010 CFR

...are required that tribal laws apply to grazing permits on the Navajo Partitioned Lands...LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining...are required that tribal laws apply to grazing permits on the Navajo Partitioned...

2010-04-01

188

The Late Jurassic Tithonian, a greenhouse phase in the Middle JurassicEarly Cretaceous `cool' mode: evidence from the cyclic  

E-print Network

The Late Jurassic Tithonian, a greenhouse phase in the Middle Jurassic­Early Cretaceous `cool' mode of cyclic facies within the rapidly subsiding Late Jurassic (Tithonian) shallow platform-interior (over 750), supporting a global, hot greenhouse climate for the Late Jurassic (Tithonian) within the overall `cool' mode

Husinec, Antun

189

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

190

The Circulation and Silence of Weaving Knowledge in Contemporary Navajo Life  

ERIC Educational Resources Information Center

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

Yohe, Jill Ahlberg

2012-01-01

191

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

ERIC Educational Resources Information Center

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

Manuelito, Kathryn D.

2006-01-01

192

The Ethical Issues in Uranium Mining Research in the Navajo Nation  

Microsoft Academic Search

We explore the experience of Navajo communities living under the shadow of nuclear age fallout who were subjects of five decades of research. In this historical analysis of public health (epidemiological) research conducted in the Navajo lands since the inception of uranium mining from the 1950s untill the end of the 20th century, we analyze the successes and failures in

BINDU PANIKKAR; DOUG BRUGGE

2007-01-01

193

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

ERIC Educational Resources Information Center

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

Goodman, James M.

194

Racing Against Time: A Report on the Leupp Navajo Immersion Project  

Microsoft Academic Search

This paper describes a U. S. Department of Education Title VII funded language preservation program at Leupp Public School in the Navajo Nation. Funded in 1997 for five years, this school-wide project is designed to help students become proficient speakers, readers, and writers of Navajo while enhancing their English language skills and preparing them to meet state academic standards. The

Michael Fillerup

195

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

ERIC Educational Resources Information Center

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

Fillerup, Michael

196

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

Federal Register 2010, 2011, 2012, 2013

... ) from the Navajo Generating Station (NGS), located on the Navajo Nation. EPA...comments on the proposed BART determination for NGS. DATES: EPA will announce dates and locations...Comments on the proposed BART determination for NGS must be postmarked no later than...

2013-06-19

197

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

Federal Register 2010, 2011, 2012, 2013

...requiring the Navajo Generating Station (NGS), located on the Navajo Nation, to reduce...reduce visibility impairment resulting from NGS at 11 National Parks and Wilderness Areas...Background II. Today's Action I. Background NGS is a coal-fired power plant located...

2013-03-19

198

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

Federal Register 2010, 2011, 2012, 2013

... ) for the Navajo Generating Station (NGS), located on the Navajo Nation, and provided...comment on our proposed BART determination for NGS. On July 26, 2013, a group of stakeholders...Comments on the proposed rulemaking for NGS must be postmarked no later than...

2013-09-25

199

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

Federal Register 2010, 2011, 2012, 2013

... ) for the Navajo Generating Station (NGS), located on the Navajo Nation, and...SRP), the operator and co-owner of NGS, submitted a letter on behalf of six stakeholders...Comments on the proposed BART determination for NGS must be postmarked no later than...

2013-07-09

200

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.

201

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

202

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.

203

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

204

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

205

Jurassic exploration trends of East Texas  

Microsoft Academic Search

This article deals with exploration and production from the Jurassic reservoirs of East Texas. The paper discussed the trapping mechanisms, structural configurations, lithologies and stratigraphic relationships. The major formations presented are the Smackover and the Haynesville (Cotton Valley).

M. W. Presly; C. H. Reed

1984-01-01

206

Jurassic exploration trends of East Texas  

SciTech Connect

This article deals with exploration and production from the Jurassic reservoirs of East Texas. The paper discussed the trapping mechanisms, structural configurations, lithologies and stratigraphic relationships. The major formations presented are the Smackover and the Haynesville (Cotton Valley).

Presly, M.W.; Reed, C.H.

1984-09-01

207

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

208

Dinoflagellates near the Cretaceous Jurassic Boundary  

Microsoft Academic Search

MANY well-preserved dinoflagellate fossils occur in Jurassic and Cretaceous marine sedimentary sections of various lithologic characteristics in the western North Atlantic and the western side of the Sacramento Valley of California1,2. We have discovered five species which are common to the two sections-las first noticed by W. R. Evitt-each occurring in the Cretaceous above the Cretaceous\\/Jurassic boundary, and not in

D. Habib; J. S. WARREN

1973-01-01

209

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

210

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

211

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

212

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

213

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

NASA Astrophysics Data System (ADS)

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

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

2006-08-01

214

Conical sandstone landforms cored with clastic pipes in Glen Canyon National Recreation Area, southeastern Utah  

NASA Astrophysics Data System (ADS)

Clusters of conical sandstone landforms, many with summit weathering pits, have developed on barren outcrops of the Jurassic Entrada Sandstone in Glen Canyon National Recreation Area, southeastern Utah. The conical landforms have developed on cylindrical bodies of fluidized sandstone (clastic pipes) that typically have near-vertical contacts with the enclosing cross-bedded, eolian sandstone. These landforms vary in size and shape due chiefly to differential erosion of the clastic pipe relative to the enclosing sandstone. The greater resistance to weathering of the clastic pipes is due in part to their higher content of calcite cement. Conical, pipe-cored landforms develop progressively from low domes to cones as high as 70 m. Some of the clastic pipes have relatively soft cores and resistant contacts, leading to the development of conical landforms with summit weathering pits. With time, the size of these pits increases as does the relief of the conical landform. The summit pits are as deep as 16 m and have width-depth ratios as low as 1.5. The resistant rims of these pits are due in part to calcite-enriched pipe contacts. Sandy pit-floor sediment is removed principally by strong wind rotors and vortices. Intense eolian activity in and near the landforms is indicated by abrasional features and pit-floor sand dunes. Factors that promote the development of these conical landforms include (i) the presence of clastic pipes, some with relatively soft cores; (ii) porous, friable, fine-grained pipe and host sandstones; (iii) aridity; (iv) strong winds; and (v) virtually sediment-free, unvegetated bedrock outcrops.

Netoff, Dennis I.; Shroba, Ralph R.

2001-08-01

215

Detrital zircon U-Pb ages of Late Triassic-Late Jurassic deposits in the western and northern Sichuan Basin margin: constraints on the foreland basin provenance and tectonic implications  

NASA Astrophysics Data System (ADS)

Upper Triassic to Upper Jurassic strata in the western and northern Sichuan Basin were deposited in a synorogenic foreland basin. Ion-microprobe U-Pb analysis of 364 detrital zircon grains from five Late Triassic to Late Jurassic sandstone samples in the northern Sichuan Basin and several published Middle Triassic to Middle Jurassic samples in the eastern Songpan-Ganzi Complex and western and inner Sichuan Basin provide an initial framework for understanding the Late Triassic to Late Jurassic provenance of western and northern Sichuan Basin. For further understanding, the paleogeographic setting of these areas and neighboring hinterlands was constructed. Combined with analysis of depocenter migration, thermochronology and detrital zircon provenance, the western and northern Sichuan Basin is displayed as a transferred foreland basin from Late Triassic to Late Jurassic. The Upper Triassic Xujiahe depocenter was located at the front of the Longmen Shan belt, and sediments in the western Sichuan Basin shared the same provenances with the Middle-Upper Triassic in the Songpan-Ganzi Complex, whereas the South Qinling fed the northern Sichuan Basin. The synorogenic depocenter transferred to the front of Micang Shan during the early Middle Jurassic and at the front of the Daba Shan during the middle-late Middle Jurassic. Zircons of the Middle Jurassic were sourced from the North Qinling, South Qinling and northern Yangtze Craton. The depocenter returned to the front of the Micang Shan again during the Late Jurassic, and the South Qinling and northern Yangtze Craton was the main provenance. The detrital zircon U-Pb ages imply that the South and North China collision was probably not finished at the Late Jurassic.

Luo, Liang; Qi, Jia-Fu; Zhang, Ming-Zheng; Wang, Kai; Han, Yu-Zhen

2014-09-01

216

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

217

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

218

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

219

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

220

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

221

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

222

Solar membrane distillation: desalination for the Navajo Nation.  

PubMed

Provision of clean water is among the most serious, long-term challenges in the world. To an ever increasing degree, sustainable water supply depends on the utilization of water of impaired initial quality. This is particularly true in developing nations and in water-stressed areas such as the American Southwest. One clear example is the Navajo Nation. The reservation covers 27,000 square miles, mainly in northeastern Arizona. Low population density coupled with water scarcity and impairment makes provision of clean water particularly challenging. The Navajos rely primarily on ground water, which is often present in deep aquifers or of brackish quality. Commonly, reverse osmosis (RO) is chosen to desalinate brackish ground water, since RO costs are competitive with those of thermal desalination, even for seawater applications. However, both conventional thermal distillation and RO are energy intensive, complex processes that discourage decentralized or rural implementation. In addition, both technologies demand technical experience for operation and maintenance, and are susceptible to scaling and fouling unless extensive feed pretreatment is employed. Membrane distillation (MD), driven by vapor pressure gradients, can potentially overcome many of these drawbacks. MD can operate using low-grade, sub-boiling sources of heat and does not require extensive operational experience. This presentation discusses a project on the Navajo Nation, Arizona (Native American tribal lands) that is designed to investigate and deploy an autonomous (off-grid) system to pump and treat brackish groundwater using solar energy. ?ench-scale, hollow fiber MD experiment results showed permeate water fluxes from 21 L/m2·d can be achieved with transmembrane temperature differences between 40 and 80?C. Tests run with various feed salt concentrations indicate that the permeate flux decreases only about 25% as the concentration increases from 0 to 14% (w/w), which is four times seawater salt concentration. The quality of the permeate water remains constant at about 1 mg/L regardless of the changes in the influent salt concentration. A nine-month MD field trial, using hollow fiber membranes and completely off-the-shelf components demonstrated that a scaled-up solar-driven MD system was practical and economically viable. Based on these results, a pilot scale unit will be constructed and deployed on the tribal lands. PMID:24552961

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

2014-01-01

223

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

224

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 Triassic­Jurassic

McRoberts, Christopher A.

225

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 Jurassic (Callovian) Todilto Formation of the southwestern United States, the fauna described

Olsen, Paul E.

226

First record of a Jurassic mammal (?"Peramura") from Ethiopia  

E-print Network

First record of a Jurassic mammal (?"Peramura") from Ethiopia WILLIAM A. CLEMENS, MARK B. GOODWIN, M.B., Hutchison, J.H., Schaff, C.R., Wood, C.B., and Colbert, M.W. 2007. First record of a Jurassic of estuarine to fluvial deposits that are thought to be of Late Jurassic (Tithonian) age. The fragment

Goodwin, Mark B.

227

JURASSIC CYCLOSTRATIGRAPHY AND PALEONTOLOGY OF THE HARTFORD BASIN  

E-print Network

A4-1 JURASSIC CYCLOSTRATIGRAPHY AND PALEONTOLOGY OF THE HARTFORD BASIN by Paul E. Olsen and Jessica, Minnesota State University, Mankato, MN 56001 INTRODUCTION Jurassic age lacustrine strata of the Hartford and interpret the cyclicity and biofacies through most of the major Jurassic intervals in the south

Olsen, Paul E.

228

ACCEPTED MANUSCRIPT Impact of basin burial and exhumation on Jurassic  

E-print Network

M ANUSCRIPT ACCEPTED ACCEPTED MANUSCRIPT Impact of basin burial and exhumation on Jurassic Several diagenetic models have been proposed for Middle and Upper Jurassic carbonates of the eastern Paris for the Middle and Late Jurassic deposits as a whole. Petrographic (optical and cathodoluminescence microscopy

Paris-Sud XI, Université de

229

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 marine reptiles of the Late Jurassic are rare, and so the discovery of the 1.8-m- long skull, Kimmeridge Clay, Upper Jurassic, palaeopathology. P liosaurus is an enigmatic, advanced sauroptery- gian

Benton, Michael

230

ISOPOD TRACKWAYS FROM THE CRAYSSAC LAGERSTA TTE, UPPER JURASSIC, FRANCE  

E-print Network

ISOPOD TRACKWAYS FROM THE CRAYSSAC LAGERSTA¨ TTE, UPPER JURASSIC, FRANCE by CHRISTIAN GAILLARD, which occurs abundantly in Late Jurassic deposits of England and France, was probably the trace-maker. Key words: trackways, isopods, intertidal, Tithonian, south- west France. The Upper Jurassic Crayssac

Paris-Sud XI, Université de

231

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

Microsoft Academic Search

BACKGROUND: Decades of improper disposal of uranium-mining wastes on the Navajo Nation has resulted in adverse human and ecological health impacts as well as socio-cultural problems. As the Navajo people become increasingly aware of the contamination problems, there is a need to develop a risk-communication strategy to properly inform tribal members of the extent and severity of the health risks.

Jamie L deLemos; Doug Brugge; Miranda Cajero; Mallery Downs; John L Durant; Christine M George; Sarah Henio-Adeky; Teddy Nez; Thomas Manning; Tommy Rock; Bess Seschillie; Chris Shuey; Johnnye Lewis

2009-01-01

232

ORIGINAL ARTICLE Navajo SandstonebrineCO2 interaction: implications  

E-print Network

and conversion of smectite to illite are likely to be the two reactions that contribute to the release of SiO2(aq). The product minerals present at the end of the experiments are illite, illite/smectite, allophane, and car, allophane and illite/smectite fill voids in sandstone grains. There is no evidence for the removal of clay

Zhu, Chen

233

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

234

Jurassic submarine arc-apron deposits and associated magma/wet-sediment interaction, northern Sierra Nevada, California  

NASA Astrophysics Data System (ADS)

Jurassic metavolcanic rocks of the Northern Sierra terrane in northern California are part of an extensive Triassic-Jurassic arc constructed along the western margin of North America. In the English Mountain area, Nevada and Sierra Counties, a well-exposed volcaniclastic sequence 3.6 km thick records Jurassic island-arc activity in a submarine environment. In the lower part of the sequence, thinly bedded andesitic volcanic sandstone turbidites and mudstones of the Lower to Middle Jurassic Sailor Canyon Formation were deposited below storm wave base in a long-lived marine basin. This unit is overlain conformably by the Middle Jurassic Tuttle Lake Formation, which records rapid accumulation of coarse-grained, calc-alkaline volcanic debris in the proximal parts of a submarine apron around a major volcano that developed within the earlier Sailor Canyon basin. The formation consists primarily of massively bedded, matrix-supported, polymict, basaltic to andesitic volcanic breccias deposited from submarine debris flows. Intercalated pillow-hyaloclastite breccias formed during local extrusion of lavas on the seafloor. Numerous intrusions cut the sequence and are petrographically and chemically identical to clasts in the debris-flow deposits. Peperite occurs along intrusion margins and as abundant isolated pockets, indicating intrusion of magma into wet, unconsolidated sediments. Elongate intrusive pods to 13.6 m in length are associated with smaller intrusive pillows and are inferred to represent a network of feeder tubes that extended from larger, coherent intrusions and supplied magma to complex zones of magma/wet-sediment interaction at shallow levels beneath the seafloor. Syndepositional intrusive activity of this type, including formation of abundant peperite, probably is a characteristic feature of submarine volcaniclastic sequences developed in proximal island-arc settings.

Templeton, Jeffrey H.; Hanson, Richard E.

2003-12-01

235

Log interpretation of shaly sandstones  

E-print Network

Simandoux); and plot (f) is de Witte (1950) . . . 70 27 Comparison of the three shaly ? sandstone equations that yield the least reliable results in sand 4 of the Reese Intracoastal Land ()2 well. Plot (d) is Alger et al (1963); plot (e) is Poupon et... 630-1 well. Plot (d) is Alger et al (1963); plot (e) is Poupon et al (1970) (modified Simandoux); and plot (f) is de Witte (1950) . 75 32 (a) Generalized diagrammatic view of a system containing both laminated and dispersed clays. (b) Schematic...

Baker, Joel Foster

2012-06-07

236

Dinosaur dynamics in the Jurassic Era  

NASA Astrophysics Data System (ADS)

Dinosaurs were fascinating animals and elicit much excitement in the classroom. Analysis of fossilized dinosaur trackways permits one to estimate the locomotion speeds and accelerations of these extinct beasts. Such analysis allows one to apply Newton's laws of motion to examples from the Jurassic Era.

Lee, Scott

2010-04-01

237

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

238

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

239

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

240

Log-Derived evaluation of shaly sandstone reservoirs  

SciTech Connect

Significant natural gas resources are known to exist in the United States in tight, low-permeability sandstones that cover a prospective area of 1,000,000 mi/sup 2/ (2,590,000 km/sup 2/). Characterization and reliable estimation of their production potential based on well logs are important although difficult task. Proper evaluation of low permeability sands based on conventional log-interpretation techniques is frequently inadequate. Furthermore, while empirical rules of thumb assist in the evaluation of localized conditions, they only provide guidelines. Recent developments in quantitative log-analysis techniques incorporate natural-gamma-ray spectral data and application of the Waxman-Smits model for detailed reservoir description. Quantitative correlations of cation exchange capacity (CEC), water salinity, porosity, and conductivity of water- and hydrocarbon-bearing shaly sand reservoirs are based on resistivity, density, neutron and natural-gamma-ray spectral data. These correlations provide important information about clay volume, reservoir porosities (total, effective) and fluid-saturation distribution (total, effective), type of clay minerals (smectite, illite, chlorite/kaolinite), their distribution in the reservoir (dispersed, laminated, structural), and log-derived indicators of potential formation damage. Field experiences are reviewed for logging and evaluating tight formations in south Texas; the Jurassic Cotton Valley trend in east Texas, Louisiana, and Arkansas; and the Tertiary Fort Union and Cretaceous Mesaverde Formations of the Piceance basin in Colorado.

Fertl, W.H.

1984-04-01

241

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

SciTech Connect

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

Dobson, L.M.; Buffler, R.T. (Univ. of Texas, Austin (USA))

1990-05-01

242

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

243

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

244

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

245

The prevalence and incidence of end-stage renal disease in Native American adults on the Navajo reservation  

Microsoft Academic Search

Whereas members of the Navajo Nation are at high risk for diabetes mellitus, there are no recent published estimates of the burden of end-stage renal disease (ESRD), an important sequela of diabetes, on the Navajo Nation, a 16 million acre area in Arizona, New Mexico, and Utah with more than 200 000 tribal members. We used data from the US

M E Hochman; J P Watt; R Reid; K L O'Brien

2007-01-01

246

Skull of a Jurassic ankylosaur (Dinosauria)  

Microsoft Academic Search

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

Kenneth Carpenter; Clifford Miles; Karen Cloward

1998-01-01

247

Jurassic hydrocarbon exploration of southern Florida  

SciTech Connect

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

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

1994-09-01

248

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

249

The origin of Jurassic reefs: Current research developments and results  

Microsoft Academic Search

Summary  In order to elucidate the control of local, regional and global factors on occurrence, distribution and character of Jurassic\\u000a reefs, reefal settings of Mid and Late Jurassic age from southwestern Germany, Iberia and Romania were compared in terms of\\u000a their sedimentological (including diagenetic), palaeoecological, architectural, stratigraphic and sequential aspects. Upper\\u000a Jurassic reefs of southern Germany are dominated by siliceous sponge—microbial

Reinhold R. Leinfelder; Manfred Krautter; Ralf Laternser; Martin Nose; Dieter U. Schmid; Günter Schweigert; Winfried Werner; Helmut Keupp; Hartmut Brugger; Regina Herrmann; Ursula Rehfeld-Kiefer; Johannes H. Schroeder; Carsten Reinhold; Roman Koch; Arnold Zeiss; Volker Schweizer; Heinrich Christmann; Götz Menges; Hanspeter Luterbacher

1994-01-01

250

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

NASA Astrophysics Data System (ADS)

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

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

2002-11-01

251

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

252

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

253

Triaxial mechanical creep behavior of sandstone  

Microsoft Academic Search

Based on laboratory results of time-dependent mechanical behavior tests, we investigated short-term and mechanical creep behavior of sandstone, observed in conventional triaxial compression experiments at room temperature, using a servo-controlled rheology testing machine. Given our short-term experimental test results, we confirmed deviatoric creep stress levels of sandstone. Multiple deviatoric stress levels were applied in steps to each sample. Each deviatoric

Shengqi YANG; Yuzhou JIANG

2010-01-01

254

Alkali solution treatment on sandstone cores  

E-print Network

in the vicinity of the producing wells during injection of alkaline water. The object of this research is to develop a technique to increase the permeability of shaly sandstone by injecting sodium hydroxide solution. In addition, information that is developed... in the vicinity of the producing wells during injection of alkaline water. The object of this research is to develop a technique to increase the permeability of shaly sandstone by injecting sodium hydroxide solution. In addition, information that is developed...

Lee, Suk Jin

2012-06-07

255

"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

256

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

257

Jurassic platform development, northwestern Gulf of Mexico  

SciTech Connect

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

Moore, C.H. Jr.

1987-05-01

258

Jurassic Deformation in and Around the Ordos Basin, North China  

Microsoft Academic Search

The Jurassic era was an important period for tectonic development of the East Asia continent in general, and can be divided into two different deformation stages around the Ordos basin in particular. It was under weak extension during the Early to Middle Jurassic, with the stretching direction in N-S to NNE-SSW, and the stretching deformation mainly occurred in zones surrounding

Yueqiao ZHANG; Changzhen LIAO; Wei SHI; Tian ZHANG; Fangang GUO

2007-01-01

259

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

260

Late Jurassic climate and its impact on carbon cycling  

Microsoft Academic Search

The climate of the Late Jurassic has been characterized by high atmospheric CO2 levels and by a monsoonal rainfall pattern. In this study we traced the evolution of the global carbon cycle through the Late Jurassic with the help of carbonate carbon isotope stratigraphy. The Oxfordian-Tithonian ?13C curve is marked by one major positive carbon isotope excursion with an amplitude

H. Weissert; H. Mohr

1996-01-01

261

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

262

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

ERIC Educational Resources Information Center

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

Parent, Sydney B.; Bunderson, Eileen D.

263

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

264

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

265

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

266

Bone-related mineral content of water samples collected on the Navajo reservation  

Microsoft Academic Search

Although dairy food intake is low among the Navajo people, hip fracture rates are lower than in Caucasians. Genetic differences in bone density have been cited as the reasons for low fracture rates among Native Americans and other segments of the population. However, more detailed examination of mineral intakes suggests that environmental factors may provide part of the explanation for

Judith Hallfrisch; Claude Veillon; Kristine Y. Patterson; A. David Hill; Irene Benn; Bessie Holiday; Ruby Burns; Sylvia Zhonnie; Frances Price; Ann Sorenson

2000-01-01

267

Pressures on Arizona Water and Energy Policy: Case Study of the Navajo Generating Station  

E-print Network

1 Pressures on Arizona Water and Energy Policy: Case Study of the Navajo Generating Station Sonya and Development With thanks to: University of Arizona, Technology and Research Initiative Fund 2013/2014 Water Sustainability Graduate Student Fellowship Program & The Renewable Energy Network, Renewable Energy Policy

Fay, Noah

268

Learn in Beauty: A Professional Development Project for Navajo Bilingual Teachers.  

ERIC Educational Resources Information Center

The Learn in Beauty Project at Northern Arizona University worked with a consortium of seven Navajo Nation school districts seeking to implement the Dine Language and Culture teaching perspective. This perspective is based on the premises that education is best when it reflects a sense of place; education should be based on the philosophy and…

Lockard, Louise; de Groat, Jennie; Bedonie, Clara

269

The Navajo Environmental Protection Commission: Developing the Capabilities for Environmental Impact Assessment and Regulation  

ERIC Educational Resources Information Center

To develop effective/efficient environmental impact assessment and regulatory capabilities, the Navajo Environmental Protection Commission will need to commit more of its limited resources to building the political support which will exert real influence at the pre-commitment stages of development decision making. (JC)

Cortner, Hanna J.

1976-01-01

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

Assumptions for Bilingual Instruction in the Primary Grades of Navajo Schools.  

ERIC Educational Resources Information Center

A review of some assumptions made in the development and implementation of a bilingual-bicultural curriculum for Navajo students in the early primary grades is presented. The curriculum set out to develop and expand the students' abilities for learning, teaching them how to learn, so they could cope with change. It set out to sensitize them to the…

Wilson, Robert D.

272

Dynamic optimization model of energy related economic planning and development for the Navajo nation  

SciTech Connect

The Navajo reservation located in portions of Arizona, New Mexico and Utah is rich in low sulfur coal deposits, ideal for strip mining operation. The Navajo Nation has been leasing the mineral resources to non-Indian enterprises for purposes of extraction. Since the early 1950s the Navajo Nation has entered into extensive coal leases with several large companies and utilities. Contracts have committed huge quantities of Navajo coal for mining. This research was directed to evaluate the shadow prices of Navajo coal and identify optimal coal extraction. An economic model of coal resource extraction over time was structured within an optimal control theory framework. The control problem was formulated as a discrete dynamic optimization problem. A comparison of the shadow prices of coal deposits derived from the dynamic model with the royalty payments the tribe receives on the basis of the present long-term lease contracts indicates that, in most cases, the tribe is paid considerably less than the amount of royalty projected by the model. Part of these discrepancies may be explained in terms of the low coal demand condition at the time of leasing and due to greater uncertainties with respect to the geologic information and other risks associated with mining operations. However, changes in the demand for coal with rigidly fixed terms of royalty rates will lead to non-optimal extraction of coal. A corrective tax scheme is suggested on the basis of the results of this research. The proposed tax per unit of coal shipped from a site is the difference between the shadow price and the present royalty rate. The estimated tax rates over time are derived.

Beladi, S.A.

1983-01-01

273

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 widespread during the Early Jurassic. This tibia, and a partial sauropod tibia from the Middle Jurassic

Benton, Michael

274

A NEW LATE JURASSIC TURTLE FROM SPAIN: PHYLOGENETIC IMPLICATIONS, TAPHONOMY AND  

E-print Network

A NEW LATE JURASSIC TURTLE FROM SPAIN: PHYLOGENETIC IMPLICATIONS, TAPHONOMY AND PALAEOECOLOGY.schouten@bristol.ac.uk Typescript received 26 October 2010; accepted in revised form 27 May 2011 Abstract: The Jurassic, and this is especially true of Jurassic turtles from Wes- tern Europe. A new genus and species of Late Jurassic turtle

Benton, Michael

275

Following votes by the Pliensbachian Working Group, the Jurassic Subcommission and the International Commis-  

E-print Network

Following votes by the Pliensbachian Working Group, the Jurassic Subcommission and Point (GSSP) for the base of the Pliensbachian Stage (Lower Jurassic) at the base of bed 73b in the Wine. Foreword The Pliensbachian is the third Stage of the Jurassic System, and the fourth Jurassic Stage

276

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

Federal Register 2010, 2011, 2012, 2013

...Integrated Weed Management Plan Within Coconino, Navajo, and Apache Counties, Arizona; McKinley, San Juan, McGill, and Cibola Counties, NM; and San Juan County, UT AGENCY: Bureau of Indian Affairs, Interior. ACTION:...

2013-01-14

277

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

Code of Federal Regulations, 2010 CFR

...BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Trespass Penalties...re-vegetation, loss of future revenue, loss of profits, loss of productivity, loss of market value, damage to other resources, and...

2010-04-01

278

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

279

Sedimentary evolution and palaeogeography of mid-Jurassic deposits of the Central High Atlas, Morocco  

NASA Astrophysics Data System (ADS)

In the axis of the Moroccan Central High Atlas rift basin, Toarcian-Middle Jurassic deposits, excepting the early Toarcian Tagoudite Formation, are represented by two formations - Agoudim and Tazigzaout - comprising clays, marls and limestones. On the margins of the basin, the lateral equivalents of these two formations are dolostone-dominated and show the lithological and environmental characteristics of the Bin El Ouidane Group recognized in the NW part of the Central High Atlas (Beni-Mellal/Azilal area). This group is overlain by clays and limestones of the Tillouguite Formation and by Bathonian red beds (silts, sandstones and conglomerates) of the Anemzi Formation. From the Toarcian to Aalenian (Agoudim Members I and II) the contrasting palaeogeographical evolution is marked by a relatively deep central basin bordered by shallow marine carbonates. The Aalenian-Lower Bajocian interval (Agoudim Member II) contains lenticular biodetritic limestones within hemipelagic deposits. These facies resulted from recurrent faulting (tectonic pulses), which was at the origin of the individualization of a series of ridges and depocentres within the High Atlas trough. During the Bajocian (Agoudim Members III and IV) the palaeogeography became homogeneous across the Central High Atlas and corresponded to a carbonate ramp with coral patch reefs. During the ?Late Bajocian (Tazigzaout Lower Member) a new palaeogeography developed with reappearance of the central depocentres. During the latest Bajocian-earliest Bathonian (Tazigzaout Upper Member) a very homogeneous carbonate ramp was again established. These times of uniform palaeogeography are interpreted as relative stable tectonic periods that were progressive stages leading to the ending of the Toarcian-Middle Jurassic sedimentary cycles in the Central High Atlas rift basin of Morocco.

Ait Addi, Abdellah; Chafiki, Driss

2013-08-01

280

Exhumed hydrocarbon traps in East Greenland: Analogs for the lower-middle Jurassic play of northwest Europe  

SciTech Connect

Four exhumed hydrocarbon traps crop out in the Traill 0 region of East Greenland, each at the footwall crest of a fault-block formed during Early Cretaceous rifting. Former oil accumulations are indicated by a pore fill or pore lining of solid bitumen within the Jurassic sandstone-dominated Vardekloft and Olympen formations. The Vardekloft Formation is divided into an undated fluvial-dominated lower unit (0-520 m) and a Bajocian-Callovian upper unit (65-1020 m) deposited in a shallow-marine environment. The Oxfordian Olympen Formation (0-250 m) contains shallow-marine and fluviodeltaic deposits. The sandstones are dominantly quartzarenites, and petrographic fabrics, such as dissolved feldspar, late quartz cement, and stylolites, are consistent with burial depths in excess of 2.5 km. Porosities ranged from 7 to 27% (generally about 20%, about one-half of which was primary), and permeabilities ranged from 1 to 622 md, prior to the formation of solid bitumen. The distribution of solid bitumen in each trap can be mapped out, allowing sealing elements and original oil-water contacts to be defined. Three of the four exhumed traps (Mols Bjerge, Laplace Bjerg, and Bjornedal) were simple one-seal structural traps. Conformable Upper Jurassic mudstone, unconformable Albian-Cenomanian mudstone, and normal faults are the three top-sealing elements. The fourth (Svinhufvuds Bjerge) was a poly-seal trap with a combined top-seal and a low-side fault closure. Preliminary estimates of the volume of original oil in place within these structures range from 0.2-1.1 billion bbl for the Mols Bjerge trap to 5.3-11.9 billion bbl for the Bjornedal trap. These estimates are prone to large errors, due to uncertainties in estimating original trap geometry, hydrocarbon saturation, and net/gross ratio, and in the understanding of volume changes of hydrocarbon in each trap during thermal degradation of the oil.

Price, S.P.; Whitham, A.G. [Univ. of Cambridge (United Kingdom)

1997-02-01

281

Study on reforestation with seabuckthorn in the Pisha Sandstone area  

Microsoft Academic Search

In northwest China, an area of more than 11?000km2 is covered by Pisha Sandstone, a kind of loosely bonded sandstone formed during the Tertiary period. Pisha Sandstone is hard when it is dry but becomes loose when it is wet. Due the nature of this sandstone, this area of northwest China is plagued with a high erosion rate (over 20?000t\\/km2yr)

Kang Zhang; Mengzhen Xu; Zhaoyin Wang

2009-01-01

282

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

283

Regional Jurassic Submarine Arc-Apron Complex in the Northern Sierra Nevada, California  

NASA Astrophysics Data System (ADS)

The Tuttle Lake Formation (TLF), a distinctive unit forming part of the wall rocks to the Mesozoic Sierra Nevada batholith in northern California, is interpreted to have developed within a major island arc fringing the western margin of North America during the Jurassic. It extends for 75 km along strike, from mountainous terrain NW of Truckee to the Mt. Tallac pendant SW of Lake Tahoe. Superb glaciated exposures at various locations along strike provide a window into the proximal parts of a submarine Jurassic arc-apron complex. The TLF is >4 km thick and consists mainly of massively bedded, matrix-supported, polymict volcanic breccias containing poorly vesicular, subangular to angular basaltic to andesitic clasts up to 2 m in length. Characteristics of the polymict breccias indicate deposition from submarine debris flows derived from slumping of near-vent accumulations of lithic debris or sector collapse of parts of the volcanic edifice. Interbeds of finer grained andesitic and silicic turbidites and ash-fall tuffs occur sparsely within the debris-flow sequence, as do volumetrically minor pillow-hyaloclastite breccias, recording local extrusion of lavas on the seafloor. Coarse-grained TLF debris-flow deposits abruptly overlie the Early to Middle Jurassic Sailor Canyon Formation, which consists dominantly of andesitic volcanic sandstones and mudstones deposited from distal turbidity currents in a long-lived, deep marine basin. This marked lithologic change records rapid influx of coarse-grained volcanogenic detritus into the Sailor Canyon basin, related to a major shift in position of volcanic centers. Available data show that the TLF accumulated in a narrow time frame in the Middle Jurassic, just prior to regional tilting and batholith emplacement at ~165 Ma. Coeval basaltic to andesitic hypabyssal intrusions typically compose >15% of the exposed area of the TLF. They have identical major- and trace-element compositions and REE patterns to clasts within the host debris-flow sequence, and all analyses plot as a tight group in calc-alkaline, volcanic-arc fields on standard discrimination diagrams. The intrusions range from 3 km in length down to smaller pods and intrusive pillows a few meters across, many of which appear to be tubular feeder conduits in 3D. Marginal peperites indicate that intrusion occurred while the host sediments were still wet and unconsolidated. Abundant, isolated pockets of globular and blocky peperite are inferred to have been supplied by conduits extending from larger intrusions. Magma/sediment interaction was generally non-explosive, but steam explosions locally played a role in generating dispersed peperite. The overall characteristics of the TLF support a model in which coarse-grained volcaniclastic deposits accumulated rapidly in a proximal submarine setting around a major vent complex within the Middle Jurassic arc. Magma/wet-sediment interaction occurred over large areas within proximal parts of the arc apron, where uprising batches of magma were unable to penetrate the thick volcaniclastic sequence to undergo extrusion. Instead, an extensive network of hypabyssal intrusions and peperite formed at shallow levels beneath the sea floor. Complex hypabyssal networks of this type are probably common in submarine arc sequences, but detailed mapping is required to document their full extent and significance.

Templeton, J. H.; Hanson, R. E.; Hargrove, U. S.; Ruff, K. L.

2005-05-01

284

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

NASA Astrophysics Data System (ADS)

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

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

1995-12-01

285

Extreme adaptations for aquatic ectoparasitism in a Jurassic fly larva  

E-print Network

bizarre fly larva (Diptera), Qiyia jurassica gen. et sp. nov., from the Jurassic of China, that represents a stem group of the tabanomorph family Athericidae. Q. jurassica exhibits adaptations to an aquatic habitat. More importantly, it preserves...

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

2014-06-24

286

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

287

A Model of Evolution of Fault Structure in Porous Sandstone Reflecting the Effect of Geometric Irregularities Associated with Early-Formed Segment Linkages  

NASA Astrophysics Data System (ADS)

We propose a model of the early evolution of the structure of strike-slip faults in porous sandstone based upon detailed maps of faults with small displacements (mm to decimeters) in the Hickory Sandstone in central Texas and the Navajo Sandstone near Moab, UT. We assume faults at a given site follow similar evolutionary paths and infer relative timing of formation of fault elements using cross cutting and high-angle abutment relationships. Faults consist of a network of hard-linked smaller segments. The number of fault segments varies along a fault and qualitatively become more numerous and preferentially clustered with increasing displacement. Lacunarity analyses and variograms of spatial density of fault segments quantitatively document the clustering of fault segments. Consistent with earlier work, we infer that faults evolve in the initial stage by linkage of an early-formed array of en echelon small faults that typically step opposite to the sense of shear. Linkage is by one of two geometrically and kinematically distinct linkage structures. With increasing fault displacement, new fault segments are preferentially added in close proximity to or within the early linkages. Accreted segments typically are arcuate and abut earlier segments at a high angle. Consequently, the spatial density of fault segments varies episodically along the fault. Early linkage structures represent geometric irregularities (roughness) along the evolving fault that we interpret to result in geometric stress concentrations that preferentially localize formation of new fault segments. This conceptual model does not demand the commonly assumed strain-hardening of the gouge of individual fault segments in order to explain the evolving complexity of fault structure with increasing displacement. The lack of an implied strain-hardening behavior is consistent with laboratory-scale fault development in porous sandstone.

Schafer, K. W.; Johnson, B.

2001-12-01

288

Effects of one and two seasons irrigation on vegetal response, Navajo Mine, northwest New Mexico  

SciTech Connect

An irrigation study was established in 1990 to compare the effects of one and two seasons of irrigation on reclamation success. Two study plots were located in the Mason 90 Reclamation Area, Navajo Mine, Northwestern New Mexico. Vegetational data was collected and in early 199, prior to the plot receiving the second season of irrigation. Additional vegetal data has been collected in 1992, 1993, and 1994. Total vegetal cover was generally higher for the plot receiving two seasons of irrigation in 1991 and 1992. However, by 1993 and in 1994, the vegetal responses for the two plots were nearly the same. It appears one season of irrigation may be adequate to establish successful reclamation at Navajo Mine.

Hyder, D.; Buchanan, H.; Burchanan, B.A. [Buchanan Consultants Ltd., Farmington, NM (United States)] [and others

1995-09-01

289

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

290

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

291

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

Microsoft Academic Search

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

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

2008-01-01

292

Place-Naming, Environment, and Perception among the Canyon de Chelly Navajo of Arizona  

Microsoft Academic Search

Place-names may provide insights into cultures' linguistics, histories, habitats, and spatial and environmental perceptions. To yield such insights, I analyze a comprehensive inventory of 245 Navajo place-names of the Canyon de Chelly system, Arizona. The analysis first identifies positional and directional linguistic elements in place-names. Frequencies of references to natural features such as canyons, prominent rocks, water features, and so

Stephen C. Jett

1997-01-01

293

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

294

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

295

Late Jurassic ductile shearing and tectonic breccias in the eastern Great Basin of Nevada and Utah  

SciTech Connect

The Paleozoic sedimentary prism was dismembered in the Late Jurassic by shearing initiated at stratigraphic positions in the following list: (1) base of Meade Peak Shale, (2) base of Summit Springs Evaporites, (3) top of contact Chert Member of the Rib Hill Formation, (4) base of Unit G of the Ely Formation, (5) base of the Ely Limestone, (6) base of the Diamond Peak Sandstone, (7) base of Chainman Shale, (8) base of the Joana Limestone, (9) base of the Pilot Formation, (10) base of Lower Guilmette Limestone, (11) in siltstone at the top of Ely Springs (Hanson Creek) Formation, (12) top and base of the Eureka Quartzite, (13) base of the Dunderberg Shale, and (14) base of Pioche Shale and top of Prospect Mountain Quartzite. The largest are regional decollectments, e.g., Summit Springs, Chainman, Blue Eagle, Silver Island, and Snake Range. The lesser shears vary in position and extent with lithofacies distribution. Shales at all levels behaved ductilely. Carbonates locally behaved ductilely up to the base of the Pilot Formation, but more commonly below the Dunderberg Shale. Brittle deformation in the carbonates produced megatectonic breccias below the shears. These regional breccias became reservoirs for the pore fluids and clay-held fluids expelled from primary source rocks and reservoirs by the dynamic pressures. Igneous plutons injected from 150-30 Ma crosscut and dilated the shear zones, creating hydrothermal systems within the tectonic reservoirs.

Welsh, J.E. Sr. (Natural Resources Geologist, Holladay, UT (United States))

1993-08-01

296

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

297

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

PubMed Central

Background Decades of improper disposal of uranium-mining wastes on the Navajo Nation has resulted in adverse human and ecological health impacts as well as socio-cultural problems. As the Navajo people become increasingly aware of the contamination problems, there is a need to develop a risk-communication strategy to properly inform tribal members of the extent and severity of the health risks. To be most effective, this strategy needs to blend accepted risk-communication techniques with Navajo perspectives such that the strategy can be used at the community level to inform culturally- and toxicologically-relevant decisions about land and water use as well as mine-waste remediation. Objective The objective of this study was to develop GIS-based thematic maps as communication tools to clearly identify high risk exposure areas and offer alternatives to minimize public and ecological health impacts. Methods Thematic maps were produced that incorporated data derived from environmental sampling and public health surveys. The maps show the location and quality of unregulated water resources and identify regulated water sources that could be used as alternatives. In addition, the maps show the location of contaminated soil and sediment areas in which disturbance of surface deposits should be avoided. Preliminary feedback was collected from an informal Navajo working group to assess the clarity and efficacy of this proposed communication method. Results The working group found the maps to be both clear and effective, and made suggestions for improvements, such as the addition of more map features. The working group predicted that once the maps are presented to the public, water hauling and soil use behaviors will change, and dialogue with chapter officials will be initiated to accelerate further risk reduction efforts. Implications Because risk communication is complicated by language barriers, lack of infrastructure, and historical mistrust of non-Navajo researchers, mapping provides an easily interpretable medium that can be objectively viewed by community members and decision makers to evaluate activities that affect toxicant exposures. PMID:19589163

2009-01-01

298

Preserving Native American petroglyphs on porous sandstone  

USGS Publications Warehouse

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

Grisafe, D.A.

1996-01-01

299

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

300

Biogeochemistry of the Triassic-Jurassic Boundary  

NASA Astrophysics Data System (ADS)

New biostratigraphic and biogeochemical data are presented from Triassic-Jurassic (Tr-J) boundary sections at Kennecott Point, Queen Charlotte Islands (QCI), Canada, Muller Canyon, Nevada, USA, and Marokopa Beach, New Zealand. The New Zealand record shows two negative excursions in ?13Corg of approximately 2‰ associated with the Tr-J transition. The QCI and Nevada boundary sections show a consistent isotopic trend indicative of multiple major perturbations to the carbon cycle: one negative excursion in ?13Corg of 2‰ at the boundary and one positive excursion of 3 to 5‰ following the boundary. The post-Tr-J boundary positive excursion is especially prominent in boundary sections from QCI, where the high organic content of the black shales makes the rocks suitable for a survey of lipid biomarkers. New GC-MS data are presented from this locality, revealing changes in the distribution and abundance of alkanes, hopanes, and steranes across the Tr-J transition. Litho-, bio- and chemostratigraphy from these boundary localities do not support a single impact cause for the late Triassic extinctions, although impact events such as the Manicouagan may well have exerted significant stress on a biosphere still recovering from the Permian-Triassic mass extinction. The data support the idea of a degraded late Triassic environment persisting for millions of years and characterized by low atmospheric oxygen and high carbon dioxide associated with Central Atlantic Magmatic Province volcanism. Global warming and sea level change may have led to destabilization of seafloor methane hydrates and runaway greenhouse conditions.

Williford, K. H.; Ward, P. D.; Garrison, G. H.

2006-12-01

301

Diagenesis of Miocene sandstones, South Louisiana  

E-print Network

of this calcite created most of the porosity in these sandstones The relative timing o. diagenetic events is as follows: 1. precipitation cf chlorite rima; mechanical compaction begins 2. precipitation of quartz ovetgrowths; mechanical compaction continues 3... logarithmic scale 1 2. (A) Thin section view of partially leached feldspars, and carbonate cement, C, (B) Thin section view of car- bonate fossil, C, as a source of carbonate cement, CC 46 13 Effect of diagenesis on quartz grain shape 51 14 First method...

Smith, Richard Lee

2012-06-07

302

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

303

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

ERIC Educational Resources Information Center

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

Benally, Louise; And Others

304

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

305

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

306

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

ERIC Educational Resources Information Center

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

Fay, George E., Comp.

307

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

USGS Publications Warehouse

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

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

1950-01-01

308

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

309

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

NASA Astrophysics Data System (ADS)

Formely, the subandean zone in the southeastern Ecuador involved large volcanic and magmatic rocks included in the Misahualli Formation and Zamora batholith, both as expression of the Jurassic cal-alcaline volcanic arc. The aim of the project carried out by the INIGEMM (Instituto Nacional de Investigación Geológico Minero Metalúrgico) was discriminate the volcanic products including a continuous set going from basalts to ryolithes and volcanoclastic rocks. Geochemical characterization was done using representative 16 whole - rock chemical analysis. The oldest rocks of the investigated area called Pachicutza Unit, include greenish to black, massive basalts and basaltic andesites, locally showing pillows structures. The texture is aphanitic to microporphyritic with slight crystal growth of plagioclase and pyroxenes. The Unit include also local pyroclastic breccias and tuffs showing variable skarnification related to the intrusion of the jurassic Zamora Batholith. Two samples of basalts show tholeiitic affinity, corresponding to an N- MORB, probably representing an early stage in opening of a regional Triassic rift reported since Colombia to Peru in the Andes. These geochemical characteristics are similar to the amphibolites of Monte Olivo Unit in the Real Cordillera. The Jurassic large volcanic assembly of the Misahualli Formation was also differenciated. Basal volcanics include green, subporphyritic andesites and volcanic breccias possibly generated at an early stage of the volcanic arc, caused by a change of extensive to compressive regime. Continental volcano sedimentary and sedimentary rock were discriminate as Nueva Esperanza and Suarez Units, respectively. The volcanosedimentary sequence include massive to laminate tuffs and tuffites of intermediate composition. The sediments of the Suarez Unit include dominant conglomerats and sandstones of fluvial domain. The regional volcanic sequence is completed by the Las Peñas Unit that includes aphanitic to porphyritic andesites and coarse volcanic breccias. Three geochemical analysis of the lavas show andesitic composition, have medium to high-K calc-alkaline and represent the products of a subduction zone. All intrusions in the area were mapped as Zamora Batholith. Nevetheless, the field observations confirm a large Jurassic batholith but also other significant minor intrusion that intrudes the cretaceous sedimentary formations of the area. Thus, magmatic rocks in the area are named as Zamora batholithic complex. Petrography of the Zamora Batholith ranges from tonalite to monzo-granite with the same qualitative mineralogy. Rocks are composed by different proportions of plagioclase, amphibole, K-feldspar, quartz, biotite, opaques and epidote, as accessory minerals has zircon, sphene and apatite. Zamora Granitoids ranged from dioritic to granitic compositions ( 60.09 - . 73.6 wt % SiO2). The Zamora Granitoids have medium to high-K calc-alkaline and represent the products of a subduction zone. Products are generated within a magmatic arc in normal conditions of maturity. The Zamora Granitoids are I - type intrusions.

Villares, Fabián; Eguez, Arturo; Yanez, Ernesto

2014-05-01

310

A stratigraphic framework for Late Jurassic Early Cretaceous gas-bearing strata  

E-print Network

A stratigraphic framework for Late Jurassic­ Early Cretaceous gas-bearing strata (Monteith Formation) in the subsurface of northwest Alberta Abstract The entire Late Jurassic­Early Cretaceous stratal

311

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

312

Simulation of mineral diagenesis in reservoirs. Application to illite formation in feldspathic sandstones  

SciTech Connect

Petroleum geologists and production engineers are faced with reservoirs where porosities and permeabilities (poroperm) have been reduced by mineral phases precipitated during the geological evolution. Diagenesis of sandstones is influenced by many factors : initial composition of the sediment, burial history, composition of infiltrated waters. An appraisal of poroperm decline due to mineral diagenesis only can result from an integration of these factors. A quantitative evaluation of diagenetic phenomena is possible using numerical modelling. A first approach of the mineral transformations can be made using a new geochemical modelling software (NEWKIN) applied to closed cells, where aqueous solution and minerals are not in equilibrium initially. Cements of illite and quartz frequently occur in sandstones bearing feldspar, such as Middle Jurassic reservoirs of the Brent Group (East Shetland Basin, North Sea) which today lie between 3500 and 4500 in depth. Results of closed cells simulations are presented, which explore the conditions of illite and silica authigenesis in this Province, particularly in terms of temperature, water composition, and kinetics (oversaturation of the waters with respect to quartz, low pH). Another key of non-equilibrium, in pervious rocks, is the flow of interstitial water. Its role must be appraised by a -[open quotes]reaction-transport[close quotes] code. A new software is presented (DIAPHORE), able to solve, at the reservoir scale, in a coupled way : (1) advection of water and chemical elements in the porous volume; (2) mass balance of the considered chemical elements in the rock volume; (3) dissolution-precipitation phenomena occurring locally (using the geochemical code precedently described); (4) a feedback of the mineral transformations on permeability and reactive surface areas through a [open quotes]textural[close quotes] model at the grain scale.

Brosse, E.; Bazin, B.; Le Gallo, Y.; Bildstein, O. (Institut Francais du Petrole, Rueil-Malmaison (France))

1996-01-01

313

Simulation of mineral diagenesis in reservoirs. Application to illite formation in feldspathic sandstones  

SciTech Connect

Petroleum geologists and production engineers are faced with reservoirs where porosities and permeabilities (poroperm) have been reduced by mineral phases precipitated during the geological evolution. Diagenesis of sandstones is influenced by many factors : initial composition of the sediment, burial history, composition of infiltrated waters. An appraisal of poroperm decline due to mineral diagenesis only can result from an integration of these factors. A quantitative evaluation of diagenetic phenomena is possible using numerical modelling. A first approach of the mineral transformations can be made using a new geochemical modelling software (NEWKIN) applied to closed cells, where aqueous solution and minerals are not in equilibrium initially. Cements of illite and quartz frequently occur in sandstones bearing feldspar, such as Middle Jurassic reservoirs of the Brent Group (East Shetland Basin, North Sea) which today lie between 3500 and 4500 in depth. Results of closed cells simulations are presented, which explore the conditions of illite and silica authigenesis in this Province, particularly in terms of temperature, water composition, and kinetics (oversaturation of the waters with respect to quartz, low pH). Another key of non-equilibrium, in pervious rocks, is the flow of interstitial water. Its role must be appraised by a -{open_quotes}reaction-transport{close_quotes} code. A new software is presented (DIAPHORE), able to solve, at the reservoir scale, in a coupled way : (1) advection of water and chemical elements in the porous volume; (2) mass balance of the considered chemical elements in the rock volume; (3) dissolution-precipitation phenomena occurring locally (using the geochemical code precedently described); (4) a feedback of the mineral transformations on permeability and reactive surface areas through a {open_quotes}textural{close_quotes} model at the grain scale.

Brosse, E.; Bazin, B.; Le Gallo, Y.; Bildstein, O. [Institut Francais du Petrole, Rueil-Malmaison (France)

1996-12-31

314

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

SciTech Connect

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

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

1991-03-01

315

Ecological Impacts of Seabuckthorn in the Pisha Sandstone Area  

Microsoft Academic Search

\\u000a There is an area of more than 11,000 km2 in northwest China which is covered by Pisha Sandstone, a kind of loosely bonded sandstone which was formed during the Tertiary\\u000a period. The sandstone is hard when it is dry and easily changes into sand when wet. The area has a very high erosion rate\\u000a (over 20,000 t\\/km2·yr) and very poor

Kang Zhang; Mengzhen Xu; Zhaoyin Wang; Xuehua Duan; Cifen Bi

316

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

317

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

318

Geometry of Wall Creek sandstones, Salt Creek Oil Field, Wyoming  

SciTech Connect

Modern gamma-ray and density well logs at the Salt Creek field define an optimum development of the middle and lower Wall Creek (First Frontier) Sandstone reservoir, which is unusually thick, well sorted, and porous in a belt about 1 mi wide that crosses the Salt Creek anticline in a north-northeasterly trend. The most distinctive aspect of the geometry of this well-sorted sandstone is its east-sloping clinoform shape in cross section. Detailed well-log control defines (1) moderate paleotopography on the basal Wall Creek regional unconformity, then (2) deposition of a local depositional shelf, shelf-edge, and north-trending slope, and finally (3) deposition of optimum sandstone reservoirs across this local shelf edge and slope by a high-energy current that appears to have flowed obliquely downslope northeastward into deeper water. If similar Wall Creek sandstones were deposited east of the Salt Creek field in the deeper part of the Powder River basin, recent wells, which are being drilled 1 mi apart, are too widely spaced to define the geometry of the individual sandstone bodies. Because of the asymmetric shape of the clinoform sandstones, hydrocarbon shows along the east or west edges of a sandstone have different implications as to the possible location of the center of the sandstone body. Many, but not all, Upper Cretaceous sandstones in this part of the basin have clinoform geometry.

Curry, W.H. III

1986-08-01

319

57 Fe Mössbauer and X-ray characterisation of sandstones  

NASA Astrophysics Data System (ADS)

Sandstones from the Free State province in South Africa have been mined and processed mainly by small scale and artisanal miners in the rural areas. In the present investigation basic fire proof and water absorption tests, X-ray and ?-ray based characterisation techniques were used to study the sandstones. The collected samples were grouped according to their apparent colour in day light conditions and the elemental analysis showed the presence of a high amount of oxygen (>52%) and silicon (>38%) with Mn, Al, Fe and Ca as major elements in proportions related to the colour distribution of the various sandstones. The uniaxial compressive stress was found to be the highest (56 MPa) for the greyish sandstone and the lowest (8 MPa) for the white sandstone sample, also associated with the lowest (Al+Fe)/Si value of 0.082. The humidity test showed that the 6 % water absorption was lower than the recommended ASTM value of 8 %. The sandstone samples were also subjected to various high temperatures to simulate possible fire conditions and it was found that the non alteration of the mineral species might be one of the reasons why the sandstones are regarded as the most refractory amongst the building materials typically used. Mössbauer spectroscopy revealed that iron is present in all the sandstones, mainly as Fe3 + with the black sandstone showing an additional presence of 3 % Fe2 + indicating that a higher iron content coupled to higher silicon content, contributes to an increase in the uniaxial compressive strength.

Mulaba-Bafubiandi, A. F.; Waanders, F. B.

2013-04-01

320

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

321

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

322

Tectonostratigraphy, Biostratigraphy, and Magnetostratigraphy of Late Triassic-Early Jurassic Red  

E-print Network

Tectonostratigraphy, Biostratigraphy, and Magnetostratigraphy of Late Triassic-Early Jurassic Red Brook Street, Box 1846, Providence Rl 02912, USA Late Triassic-Early Jurassic predominately continental red beds formed during the Triassic/Jurassic rifting of Pangeacrop out over large portions of northern

Olsen, Paul E.

323

CAUSES AND CONSEQUENCES OF THE TRIASSIC-JURASSIC MASS EXTINCTION AS SEEN FROM THE HARTFORD BASIN  

E-print Network

B5-1 CAUSES AND CONSEQUENCES OF THE TRIASSIC-JURASSIC MASS EXTINCTION AS SEEN FROM THE HARTFORD of the most severe mass extinctions of the Phanerozoic, the Triassic-Jurassic event is greater or equal dinosaurs (whose descendants survive as birds) and mammals. The Triassic-Jurassic mass extinction may have

Olsen, Paul E.

324

Paleomagnetism of Upper Jurassic to Lower Cretaceous volcanic and sedimentary rocks from the western Tarim  

E-print Network

Paleomagnetism of Upper Jurassic to Lower Cretaceous volcanic and sedimentary rocks from tests. Six sites of Upper Jurassic red beds have a magnetic component that was likely acquired after; Cretaceous; Jurassic #12;1. Introduction The exceptional topographic relief and high strain rates in central

Paris-Sud XI, Université de

325

The Neuquen composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the  

E-print Network

Jurassic from the Neuque�n basin (Argentina) M.P. Iglesia Llanos aY *, A.C. Riccardi b a Laboratorio de have allowed to construct the Lower Jurassic Neuque�n Composite Section. This composite section, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower

Utrecht, Universiteit

326

Systematics, Ontogeny, and Phylogenetic Implications of Exceptional Anatomically Preserved Cycadophyte Leaves from the Middle Jurassic  

E-print Network

Anatomically Preserved Cycadophyte Leaves from the Middle Jurassic of Bearreraig Bay, Skye, Northwest Scotland Implications of Exceptional Anatomically Preserved Cycadophyte Leaves from the Middle Jurassic of Bearreraig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 I. Abstract The Middle Jurassic (Aalenian-Bajocian) shallow marine deposits of Bearreraig Bay

Law, Wayne

327

Geological Society of America Paleogeographic and tectonic implications of Jurassic sedimentary  

E-print Network

of Jurassic sedimentary and volcanic sequences in the central Mojave block Elizabeth R. Schermer Department that at least part, and possibly all, of the Fairview Valley For- mation is late Early Jurassic in age. We-marine rocks as Jurassic instead of Triassic suggests a period of uplift and erosion or nondeposition extending

Busby, Cathy

328

Jurassic Chicken: An Avian Bipedal Robot 2001 Florida Conference on Recent Advances in Robotics  

E-print Network

Jurassic Chicken: An Avian Bipedal Robot 2001 Florida Conference on Recent Advances in Robotics May Jurassic Chicken is a whimsically dubbed Master's thesis research platform. Based on avian physiology bipeds. Biped dinosaurs like the Dinonychus (or "velociraptor") recently popularized by the Jurassic Park

Schwartz, Eric M.

329

Early Jurassic mass extinction: A global long-term event Crispin T. S. Little  

E-print Network

Early Jurassic mass extinction: A global long-term event Crispin T. S. Little Department of Geology extinctions occurred in the early Toarcian, following a regional anoxic event. The Early Jurassic mass between the Early Jurassic Pliensbachian and Toarcian stages. This is a much smaller peak in total

Benton, Michael

330

STRATIGRAPHIC RECORD OF TRIASSIC-JURASSIC COLLISIONAL TECTONICS IN THE BLUE MOUNTAINS PROVINCE,  

E-print Network

STRATIGRAPHIC RECORD OF TRIASSIC-JURASSIC COLLISIONAL TECTONICS IN THE BLUE MOUNTAINS PROVINCE in the Blue Mountains province (BMP) of northeastern Oregon preserve a well studied record of Triassic­Jurassic to Early Jurassic deposits that change up section from (1a) older volcanic and volcaniclastic deposits

Dorsey, Becky

331

TECTONICS, VOL. 5, NO. 7, PAGES 1089-1114, DECEMBER1986 THE LATE JURASSIC OBLIQUE COLLISIONAL  

E-print Network

TECTONICS, VOL. 5, NO. 7, PAGES 1089-1114, DECEMBER1986 THE LATE JURASSIC OBLIQUE COLLISIONAL configuration of SW Japan mainly reflects a late Jurassic-early Cretaceous orogeny. The region is divided is divided into a Jurassic olistostrome known as the Tanba zone and a hinterland area comprising continental

Paris-Sud XI, Université de

332

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,2 , neither of which is well preserved. Here we describe a small new theropod dinosaur from the Late Jurassic

Cai, Long

333

Contributions to the Paleontology of New Jersey (II) THE TRIASSIC-JURASSIC MASS EXTINCTION  

E-print Network

Contributions to the Paleontology of New Jersey (II) 10 THE TRIASSIC-JURASSIC MASS EXTINCTION Olsen- competitors except crocodylomorphs. Early Jurassic land tetrapod assemblages were thus of very low diversity the makers of the familiar brontozoid tracks, such as the famous Eubrontes so common in Early Jurassic

Olsen, Paul E.

334

Project EARTH-13-CMN1: Determining and calibrating the tempo of Early Jurassic environmental change.  

E-print Network

Project EARTH-13-CMN1: Determining and calibrating the tempo of Early Jurassic environmental change. S.P. Hesselbo, C. Mac Niocaill & J. Riding (BGS). The Early Jurassic was a time of extreme are thought to have had a significant influence on the evolution of Jurassic marine biota (e.g. van de

Henderson, Gideon

335

Resetting the evolution of marine reptiles at the Triassic-Jurassic boundary  

E-print Network

Resetting the evolution of marine reptiles at the Triassic-Jurassic boundary Philippa M. Thorne predators in the Early Jurassic, and an abundant and diverse component of Mesozoic marine ecosystems. Despite their ecological importance, however, the Early Jurassic species represent a reduced remnant

Benton, Michael

336

New heterodontosaurid specimens from the Lower Jurassic of southern Africa and the early  

E-print Network

New heterodontosaurid specimens from the Lower Jurassic of southern Africa and the early is best known from the Lower Jurassic upper `Stormberg Group' (upper Elliot and Clarens formations, the evolution of ornithischians during the Late Triassic and much of the Jurassic is poorly understood (e

337

PELAGOSAURUS TYPUS BRONN, 1841 (MESOEUCROCODYLIA: THALATTOSUCHIA) FROM THE UPPER LIAS (TOARCIAN, LOWER JURASSIC) OF SOMERSET, ENGLAND  

E-print Network

, LOWER JURASSIC) OF SOMERSET, ENGLAND STEPHANIE E. PIERCE and MICHAEL J. BENTON Department of Earth is fully documented and described from the Upper Lias (Toarcian, Lower Jurassic) of England. The material in abundance in the Lower Jurassic of Western Europe (Carroll, 1988). These crocodiles diversified

Benton, Michael

338

Functional anatomy and feeding biomechanics of a giant Upper Jurassic pliosaur (Reptilia: Sauropterygia)  

E-print Network

Functional anatomy and feeding biomechanics of a giant Upper Jurassic pliosaur (Reptilia. In the Kimmeridgian ecosystem, we conclude that Late Jurassic pliosaurs were generalist predators at the top- zoic from the Late Triassic to Late Cretaceous, some 150 Myr. Towards the end of the Early Jurassic

Benton, Michael

339

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

E-print Network

A new Bathonian (Middle Jurassic) microvertebrate site, within the Chipping Norton Limestone. & DARTNALL, D. L. 1992. A new Bathonian (Middle Jurassic) microvertebrate site within the Chipping Norton Cresent, Bridge of Don, Aberdeen AB2 SEW. 1. INTRODUCTION The Middle Jurassic was a key episode

Benton, Michael

340

Thermal maturity of the Upper Triassic-Middle Jurassic Shemshak Group (Alborz Range, Northern Iran)  

E-print Network

1 Thermal maturity of the Upper Triassic-Middle Jurassic Shemshak Group (Alborz Range, Northern of the Shemshak Group (Upper Triassic-Middle Jurassic) from fifteen localities along the Alborz Range of Northern deeply buried part of the Shemshak Group (i.e., Tazareh section) corresponds to Late Jurassic

Paris-Sud XI, Université de

341

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 learned from it of Jurassic palaeoenvironments, biostratigraphy and magnetostratigraphy. Additionally of Jurassic successions in the Skye area of the Hebrides Basin, including new summary diagrams, and we

Hesselbo, Stephen P.

342

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

343

Triassic-Jurassic faunal and floral transition in the Fundy Basin, Nova  

E-print Network

Triassic-Jurassic faunal and floral transition in the Fundy Basin, Nova Scotia Paul E. Olsen Considered one of the five great mass extinctions of the Phanerozoic, the Triassic- Jurassic event), although dissenters remain (e.g. Hallam, 2002; Tanner et al., 2004). Explanations for the Triassic-Jurassic

Olsen, Paul E.

344

Geophys. J. Int. (2003) 153, 2026 A first palaeomagnetic study of Jurassic formations from the Qaidam  

E-print Network

Geophys. J. Int. (2003) 153, 20­26 A first palaeomagnetic study of Jurassic formations from palaeomagnetic study on Upper Jurassic red beds collected at nine sites near Huatugou (38.46 N, 90.75 E a large-scale tectonic evolution of the Asian continent since the late Jurassic. This study suggests

Cogne, Jean-Pascal

345

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 characteristics might give clues about the pes morphology of the South American Jurassic sauropods, whose foot

Benton, Michael

346

Page 1 of 45 Gigantism among Late Jurassic limulids: new ichnological evidence from  

E-print Network

Page 1 of 45 Accepted M anuscript 1 Gigantism among Late Jurassic limulids: new ichnological was discovered in Upper Jurassic limestones from the Causses Basin (Causse M�jean, Loz�re, France gigantic horseshoe crabs in the Jurassic of Western Europe, thus casting doubt on the postulated increase

347

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

348

Foraminifera of the Ellis Group, Jurassic, at the Type Locality  

E-print Network

UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS PROTOZOA ARTICLE 2 Pages 3-20, Plates 1-4, Figures 1-5 FORAMINIFERA OF THE ELLIS GROUP, JURASSIC, AT THE TYPE LOCALITY By CECIL G. LALICKER ARTICLE 3 Pages 1-15, Plates 1-2 FORAMINIFERA OF THE TYPE... ; pp. 1-184, pls. 1-38, figs. 1-7 ; Oct. 15, 1948. UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS PROTOZOA, ARTICLE 2, PAGES 3-20, PLATES 1-4, FIGURES 1-5 FORAMINIFERA OF THE ELLIS GROUP, JURASSIC, AT THE TYPE LOCALITY By CECIL G. LALICKER 1...

Lalicker, Cecil G.

1950-02-24

349

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

350

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

. Pseudomorphs of siderite are present in local residual, iron-rich cores of boxworks. Workers in the late nineteenth through mid-twentieth centuries, many of whom found evidence for siderite precusors, concluded products of the oxidation of siderite-cemented (precursor) concretions that were very similar in both size

Nebraska-Lincoln, University of

351

Jurassic deep-water fans in the Neo-Tethys Ocean: The Kashafrud Formation of the Kopet-Dagh Basin, Iran  

NASA Astrophysics Data System (ADS)

The Middle Jurassic Kashafrud Formation of northeast Iran was deposited in the Kopet-Dagh Basin, linked to the Neo-Tethys Ocean. The 2 km thick succession commences with fluvio-marine boulder conglomerates that occupy bedrock valleys, but the bulk of the formation comprises a deep-water succession of interbedded sandstone and mudstone packages with trace fossils and sparse ammonites. Neogene collisional events deformed the strata to create the Kopet-Dagh mountains. The deep-water succession represents channel-lobe systems and associated levees and overbank areas on slope to basin-floor fans. Northward paleoflow suggests that rivers drained uplands along the Paleo-Tethys Suture zone, forming fan deltas on a narrow shelf, with associated sediment transport to deeper water. Coarse sands, extrabasinal pebbles, and plant fragments are present throughout the formation, and a thick boulder conglomerate unit lies within the turbidite succession. These observations suggest proximity to terrestrial sources throughout deposition. Sandstone packages are mainly less than 10 m thick (maximum 84 m), and numerous lensoid packages of thick-bedded sandstone tens of meters thick and up to 200 m wide represent submarine channel fills. Thick-bedded lenses and sheets show a relatively narrow range of paleoflow direction and represent major submarine conduits, whereas the more varied paleoflow direction of thin-bedded packages suggests that many were deposited on levees. The presence in the Kashafrud Formation of potential source rocks in the form of organic-rich mudstones and abundant plant fragments suggests that the formation may have contributed to hydrocarbon fields within overlying formations. Sandstone sheets and channel fills could form local reservoirs.

Poursoltani, Mehdi Reza; Moussavi-Harami, Reza; Gibling, Martin R.

2007-05-01

352

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

353

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

354

Late Jurassic Epiphyton-like cyanobacteria: Indicators of long-term episodic variation in marine bioinduced microbial calcification?  

E-print Network

Late Jurassic Epiphyton-like cyanobacteria: Indicators of long-term episodic variation in marine Epiphyton Late Jurassic Romania Epiphytaceans occur in Late Jurassic shallow-marine reef limestones, but their precise affinities remain elusive and the group may be heterogeneous. These Late Jurassic examples most

Riding, Robert

355

TRIASSIC AND JURASSIC FORMATIONS OF THE NEWARK BASIN  

E-print Network

TRIASSIC AND JURASSIC FORMATIONS OF THE NEWARK BASIN PAUL E. OLSEN Bingham Laboratories, Department of Biology, Yale University, New Haven, Connecticut Abstract Newark Supergroup deposits of the Newark Basin (or lack thereof). Fossils are abundant in the sedimentary formations of the Newark Basin and provide

Olsen, Paul E.

356

Basic aspects of Jurassic landscape development in southeastern central Asia  

SciTech Connect

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

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

1986-11-01

357

Hettangian (Early Jurassic) Dinosaur Tracksites from the Mecsek Mountains, Hungary  

Microsoft Academic Search

Isolated theropod dinosaur tracks were first collected in Hungary from Hettangian (Lower Jurassic) beds of the Mecsek Coal Formation in 1966 and described as Komlosaurus carbonisKordos, 1983. Our study is based on newly collected material from additional track-bearing beds. The description of the two largest preserved surfaces containing a total of 102 tracks that can be referred to as 21

Attila ?si; József Pálfy; László Makádi; Zoltán Szentesi; Péter Gulyás; Márton Rabi; Gábor Botfalvai; Kinga Hips

2011-01-01

358

Jurassic faults of southwest Alabama and offshore areas  

Microsoft Academic Search

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

R. M. Mink; B. H. Tew; B. L. Bearden; E. A. Mancini

1991-01-01

359

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

360

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

361

Jurassic Park as a Teaching Tool in the Chemistry Classroom.  

ERIC Educational Resources Information Center

Describes how the science fiction novel "Jurassic Park" has been used to provide the focus for summate discussions among gifted high school students participating in a state-sponsored, science-intensive summer program. Discusses adaptations of this approach for use in chemistry classes from the high school to intermediate college level. (JRH)

Jollis, W. Gary, Jr.

1996-01-01

362

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

363

Jurassic Management: Chaos and Management Development in Educational Institutions.  

ERIC Educational Resources Information Center

Investigates the failure of "Jurassic" management: visioning, consensus value systems, proactively created teams, and development planning. Applied chaos theory can help self-managing schools and colleges avoid disaster and improve their management-development programs. Survival in turbulent times is based on educational managers' capacity to make…

Gunter, Helen

1995-01-01

364

Kemik sandstones, Arctic National Wildlife Refuge (ANWR), Alaska  

Microsoft Academic Search

In the Sadlerochit Mountains area of ANWR, the Kemik Sandstone of Hauterivian-Barremian age ranges to at least 35 m (120 ft) of very well sorted, fine-grained quartzose sandstone with minor pebble conglomerate. It is an elongate body traceable for over 160 km (100 mi) from the eastern Sadlerochit Mountains into the subsurface near the Sagavanirtok River to the west. In

C. G. Mull; K. E. Adams

1985-01-01

365

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

366

KGEOFLOW: A new reactive transport simulator for sandstone matrix acidizing  

Microsoft Academic Search

This paper reports on the first modeling of sandstone matrix acidization using a comprehensive geochemical simulator based on the partial local equilibrium assumption. This new model allows any combination of kinetic and equilibrium reactions involving any number of chemical species, which greatly increases the simulator's predictive abilities compared to existing sandstone acidizing models. The new simulator, KGEOFLOW, which is applicable

S. D. Sevougian; Larry Lake; Robert Schechter

1995-01-01

367

Grants to Indian-Controlled Postsecondary Educational Institutions and the Navajo Community College Act. Hearing Before the United States Senate Select Committee on Indian Affairs, 95th Congress, 1st Session on S. 468 - To Amend the Navajo Community College Act; S. 1215 - To Provide for Grants to Indian-Controlled Postsecondary Educational Institutions, and for Other Purposes (July 28, 1977).  

ERIC Educational Resources Information Center

Presenting testimony, these 1977 Senate Hearings deal with S. 468, a bill designed to amend the Navajo Community College Act of 1971 to insure adequate funding for operation and expansion of the college on the Navajo Reservation, and S. 1215, designed to amend the Indian Self Determination and Education Assistance Act of 1975 by adding a third…

Congress of the U.S., Washington, DC. Senate Select Committee on Indian Affairs.

368

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

369

Building a Seismic Sequence Stratigraphy Model Using HorizonCubes: A Jurassic Case Study in the Arabian Basin  

NASA Astrophysics Data System (ADS)

Understanding the regional stratigraphic framework of the Middle and Upper Jurassic (Late Callovian-Oxfordian - Early Kimmeridgian) formations in the Arabian Basin is extremely important for unlocking the area's hydrocarbon potential. With recent advances in computing power and interpretation software, seismic sequence stratigraphy has become an important tool in reservoir characterization, and for reducing exploration risk. This paper provides a workflow that can be used to model seismic horizons using a dip steering volume. The workflow consists of data conditioning to produce a dip steering volume to generate a volume of densely spaced, automatically tracked seismic horizons, a "HorizonCube". The horizons are derived from the dip and azimuth information stored in the dip steered seismic volume model. In the Wheeler domain, the seismic volume is recomputed and flattened accordingly to match the Wheeler transformed HorizonCube. Based on the HorizonCube model, it is possible to identify stratigraphic carbonate buildups and depositional sequences. Isolating the horizon cube into smaller packages shows the dynamic variation in the deposition of sediments through time and space during the Jurassic period, starting from the top of Minjur sandstone to the Arab D limestone. The geologist is also able to identify system tracts with stratigraphic surfaces and estimate a stratigraphic base level curve. The approach is extended to integrate with the well correlation panel for better confidence in picking well tops. Visualizing system tract-interpretations together with the HorizonCube and overlaying the seismic and Wheeler-transformed domains helps to identify depositional features of interest that may form stratigraphic traps.

AlYousuf, T. Y.

2012-12-01

370

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

371

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

372

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

373

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

374

The Impact of Power Developments on the Navajo Nation. Lake Powell Research Project Bulletin Number 7, April 1975.  

ERIC Educational Resources Information Center

The Federal government and private corporations involved in energy production are placing great emphasis on the strip-mining of vast coal reserves. The Navajo Nation, whose lands contain 20 billion tons of low-sulphur coal, sells vast quantities of its natural resources for use in the urban centers of Arizona and southern California. However, the…

Robbins, Lynn A.

375

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

376

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

Federal Register 2010, 2011, 2012, 2013

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

2012-08-22

377

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

378

Lack of founder effect for an identical mtDNA depletion syndrome (MDS)-associated MPV17 mutation shared by Navajos and Italians.  

PubMed

Navajo neurohepatopathy is a hepato-cerebral variant of mitochondrial DNA depletion syndrome due to a specific mutation in MPV17, a gene located on human chromosome 2p. The same mutation was reported in an Italian family. To understand whether the MPV17 mutation was transmitted by descent from a common ancestor to Navajos and Italians we constructed a dense haplotype of the MPV17 locus using suitable single nucleotide polymorphisms. Complete discordance between Italian and Navajo haplotypes rules out the former hypothesis, suggesting that the mutation occurred independently in the two populations. PMID:18261905

Spinazzola, Antonella; Massa, Valeria; Hirano, Michio; Zeviani, Massimo

2008-04-01

379

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

380

Sedimentology, diagenesis, and petrophysics of selected Cherokee group (Desmoinesian) sandstones in southeastern Kansas. Part 2  

SciTech Connect

Medium to very fine-grained sandstones of the Cherokee Group in S.E. Kansas were deposited by unidirectional currents in nearshore, continental channels resulting in sandstone deposits up to 35 m (116 ft) thick. Five lithofacies have been established: (1) conglomeratic sandstones subdivided into thin basal and thick sequence- capping conglomerates, (2) stacked sandstones, (3) crossbedded coarse sandstones, (4) rippled fine sandstones; and (5) interbedded sandstones, shales, and siltstones. The following diagenetic stages were established: Stage 1: rare, localized precipitation of concretionary calcite and siderite cements in both sandstones and shales; Stage 2: extensive chlorite coatings on grains and silica cementation; and Stage 3: patchy kaolinite, siderite, and dolomite-ankerite cements develop while feldspars, micas, and argillaceous rock fragments dissolve. A model is proposed for Cherokee Group sandstones which shows that coarser grain size, less cementation, and fewer argillaceous rock fragments are found in the coarse sandstone lithofacies in the lower portion of sandstone sequences. 96 references.

Woody, M.D.

1983-06-01

381

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

382

Magnetic fabrics in the Jurassic-Cretaceous continental basins of the northern part of the Central High Atlas (Morocco): Geodynamic implications  

NASA Astrophysics Data System (ADS)

The aim of this work is to study the Anisotropy of the Magnetic Susceptibility (AMS) in two Jurassic-Cretaceous synclines located in the northern border of the Central High Atlas (Morocco): the Aït Attab and Ouaouizaght basins. AMS is used in order to obtain the magnetic fabric and its relationship with the kinematic evolution of both basins. The tectonic evolution of the basins, still under discussion, is mostly considered as the result of inversion during Tertiary and perhaps since Bathonian, of extensional and/or strike-slip Jurassic basins. Both basins are filled with Upper Jurassic to Lower Cretaceous silts and sandstones, with less frequent marine marly limestones. The bulk magnetic susceptibility (km) generally shows higher values in the red facies (163.2 E-6 in AT and 168.6 E-6 in WZ) than in the yellowish marly limestones (97.88 E-6 in AT and 132 E-6 in WZ). Most sites show an oblate magnetic fabric. The rock magnetic analyses indicate that the main carrier of the magnetic susceptibility for the red facies is hematite, whereas in the yellowish facies there is a dominance of paramagnetic minerals. In both basins, the magnetic lineation (long axis of the ellipsoid, kmax axes) shows a predominant E-W direction. The overlapping of the stress fields during the Atlasic basins evolution, in both compressional and extensional regimes and hinder the straightforward interpretation of the magnetic fabrics. However, a coeval N-S compression during the times of sedimentation with an E-W transtension can explain the magnetic lineation found in many of the sites analyzed in the present work. There are also other less frequent directions of kmax axes (NE-SW and NW-SE) are interpreted as the result of local change of the stress field during the early extensional stage of basin formation.

Moussaid, B.; El Ouardi, H.; Casas-Sainz, A.; Villalaín, J. J.; Román-Berdiel, T.; Oliva-Urcia, B.; Soto, R.; Torres-López, S.

2013-11-01

383

Resonance ultrasound spectroscopy measurements of sandstone at high temperature.  

PubMed

Deep underground wells, such as those of interest to the oil and gas as well as geothermal industries, are often found in large sandstone formations. In order for drilling, enhancement, and advanced engineering techniques such as hydraulic fracturing to be efficient and successful, the mechanical properties of materials that make up the reservoir must be accurately known. We have used resonant ultrasound spectroscopy (RUS) to determine the physical properties of Berea Sandstone, such as the elastic moduli. In contrast to single crystals or high quality polycrystalline samples, the porous and attenuating nature of sandstone makes an acoustic study of sandstone very challenging. Additionally, the sandstones must be studied at high temperatures in order to simulate conditions that are found in the field. We will present our work on the temperature dependence of the elastic moduli of sandstone (between room temperature and 205 °C.) Our measurements show that Berea sandstone is a very soft material with a bulk modulus of about 6 GPa as compared to 76 GPa for aluminum. Furthermore, a ~10% softening was observed with decrease in temperature, down to a temperature of 110°C, followed by a ~7% hardening down to ambient temperature. PMID:25235518

Davis, Eric S; Sturtevant, Blake T; Sinha, Dipen N; Pantea, Cristian

2014-04-01

384

Role of clay minerals in the physicomechanical deterioration of sandstone  

NASA Astrophysics Data System (ADS)

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

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

2008-06-01

385

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

E-print Network

ft (2347. 0 to 2865. 1 m). The sandstones are isolated in thick marine shales in an area that was previously believed to lack sandstones of significant thickness. Cores from the field and from one wildcat well were described in order to interpret... deposited in channels. Soft ? sediment deformation is common in the core. One 70-ft (21. 3 m) interval displays consistent high dip of 24', and is interpreted to be a rotated slump block. The sandstones were deposited by turbidity currents that were...

Whitten, Christopher James

2012-06-07

386

Helping Mother Earth Heal: Diné College and Enhanced Natural Attenuation Research at U. S. Department of Energy Uranium Processing Sites on Navajo Land  

Microsoft Academic Search

\\u000a Diné College is a key stakeholder and partner with the U.S. Department of Energy in efforts to develop and implement sustainable\\u000a and culturally acceptable remedies for soil and groundwater contamination at uranium mill tailings processing and disposal\\u000a sites on Navajo Nation land. Through an educational philosophy grounded in the Navajo traditional living system which places\\u000a human life in harmony with

William J. Waugh; Edward P. Glenn; Perry H. Charley; Marnie K. Carroll; Beverly Maxwell; Michael K. O’Neill

387

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

388

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

389

Potential Triassic and Jurassic CO2 Storage Reservoirs in the Skagerrak Area  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

390

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

NSDL National Science Digital Library

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

Klauk, Erin

391

Examination of the relationship between Navajo generating station emissions and aerosol concentrations at Page, Arizona  

SciTech Connect

Identifying the chemical/physical characteristics and source of pollutants contributing to low lying wintertime layered hazes in the canyons along the Colorado River where it cuts through the Colorado River Plateau area is one objective of the subregional cooperative electric utility, national park service (NPS), Environmental Protection Agency (EPA) and Department of Defense (DOD) Study, (SCENES) consortium of industrial and government agencies. As part of SCENES, a short term special study, the winter haze intensive tracer experiment (WHITEX) was specially formulated to asses the feasibility of various receptor modeling techniques to attribute emissions from the Navajo Generating Station to aerosol concentrations in three National Park Service sites, Canyonlands and Grand Canyon National Parks and Glen Canyon National Recreation Area, to relate aerosol concentrations to atmospheric extinction and finally to relate extinction to visibility impairment.This paper focuses on a subset of WHITEX, the source of visibility reducing aerosols at Page (Lake Powell), Arizona.

Iyer, H.K. (Colorado State Univ., Fort Collins, CO (USA)); Malm, W.C. (National Park Service, Colorado State Univ., Fort Collins, CO (US))

1988-01-01

392

Assistive technology provision within the navajo nation: user and provider perceptions.  

PubMed

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

Reisinger, Kim D; Ripat, Jacquie D

2014-11-01

393

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

394

Upper Jurassic of east Texas, a stratigraphic sedimentologic reevaluation  

Microsoft Academic Search

The Smackover-Haynesville of east Texas has long been modeled as a simple progradational carbonate-evaporite ramp. Recent data indicate that the conventional ramp model for this sequence should be abandoned in favor of an evolving rimmed shelf to platform model, forming in response to changes in rate of relative sea level rise during the Late Jurassic. Evidence for Smackover-Haynesville shelves include:

C. H. Moore; K. McGillis; S. Stewart; S. Wilkinson; G. Harwood

1985-01-01

395

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

396

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

397

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

398

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

399

A 122.5-kilobase deletion of the P gene underlies the high prevalence of oculocutaneous albinism type 2 in the Navajo population.  

PubMed

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 molecular defect has been previously reported. In the present study, we show that albinism in one Native American population, the Navajo, is caused by a LINE-mediated 122.5-kilobase deletion of the P gene, thus demonstrating that albinism in this population is OCA2. This deletion appears to be Navajo specific, because this allele was not detected in 34 other individuals with albinism who listed other Native American origins, nor has it been reported in any other ethnic group. The molecular characterization of this deletion allele allowed us to design a three-primer polymerase chain reaction system to estimate the carrier frequency in the Navajo population by screening 134 unrelated normally pigmented Navajos. The carrier frequency was found to be approximately 4.5%. The estimated prevalence of OCA2 in Navajos is between approximately 1 per 1,500 and 1 per 2,000. We further estimate that this mutation originated 400-1,000 years ago from a single founder. PMID:12469324

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

2003-01-01

400

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

PubMed Central

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 molecular defect has been previously reported. In the present study, we show that albinism in one Native American population, the Navajo, is caused by a LINE-mediated 122.5-kilobase deletion of the P gene, thus demonstrating that albinism in this population is OCA2. This deletion appears to be Navajo specific, because this allele was not detected in 34 other individuals with albinism who listed other Native American origins, nor has it been reported in any other ethnic group. The molecular characterization of this deletion allele allowed us to design a three-primer polymerase chain reaction system to estimate the carrier frequency in the Navajo population by screening 134 unrelated normally pigmented Navajos. The carrier frequency was found to be ?4.5%. The estimated prevalence of OCA2 in Navajos is between ?1 per 1,500 and 1 per 2,000. We further estimate that this mutation originated 400–1,000 years ago from a single founder. PMID:12469324

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

2003-01-01

401

The evolution of Iberia during the Jurassic from palaeomagnetic data  

NASA Astrophysics Data System (ADS)

A revision of Jurassic palaeomagnetic data from Iberia has been carried out in order to investigate the consistency between the palaeomagnetic information and the tectonic models proposed for the western Mediterranean. Due to the presence of a widespread (but partial) remagnetization which affected most Jurassic sediments in Iberia, selection criteria have been designed to avoid completely remagnetized sites. A total of 72 sites have been considered for the palaeomagnetic discussion (35 sites from the Messejana-Plasencia dolerite dyke, 14 sedimentary sites from the Iberian Range and 23 sites from the Betic Cordillera). Three palaeopoles for Iberia have been selected (from the Iberian Massif and from the Iberian Range) for the period around 200 Ma, the Toarcian-Aalenian and the Oxfordian. Data from the Subbetic Zone (Betic Cordillera) are used to constrain the palaeolatitude of the Iberian microplate. Iberian data are in general agreement with the BC02 master curve and the reconstruction parameters used to transfer the Iberian data to Europe, but lower palaeolatitudes than predicted by BC02 master curve are observed in Iberia for the Late Jurassic. Iberia reached a maximum in palaeolatitude during the Toarcian-Aalenian (the reference point of Madrid was at about 37°), and since then, the palaeolatitude decreased (Madrid was at 22° by the Kimmeridgian). Tectonic reference models for the Western Mediterranean (Stampfli and Borel, 2002, 2004) do not fit the Iberian declinations and palaeolatitudes. New palaeogeographic reconstructions are proposed for the Hettangian-Sinemurian, the Toarcian-Aalenian and the Oxfordian.

Osete, María-Luisa; Gómez, Juan J.; Pavón-Carrasco, Fco. Javier; Villalaín, Juan J.; Palencia-Ortas, Alicia; Ruiz-Martínez, Vicente. C.; Heller, Friedrich

2011-04-01

402

A Jurassic mammaliaform and the earliest mammalian evolutionary adaptations.  

PubMed

The earliest evolution of mammals and origins of mammalian features can be traced to the mammaliaforms of the Triassic and Jurassic periods that are extinct relatives to living mammals. Here we describe a new fossil from the Middle Jurassic that has a mandibular middle ear, a gradational transition of thoracolumbar vertebrae and primitive ankle features, but highly derived molars with a high crown and multiple roots that are partially fused. The upper molars have longitudinal cusp rows that occlude alternately with those of the lower molars. This specialization for masticating plants indicates that herbivory evolved among mammaliaforms, before the rise of crown mammals. The new species shares the distinctive dental features of the eleutherodontid clade, previously represented only by isolated teeth despite its extensive geographic distribution during the Jurassic. This eleutherodontid was terrestrial and had ambulatory gaits, analogous to extant terrestrial mammals such as armadillos or rock hyrax. Its fur corroborates that mammalian integument had originated well before the common ancestor of living mammals. PMID:23925238

Zhou, Chang-Fu; Wu, Shaoyuan; Martin, Thomas; Luo, Zhe-Xi

2013-08-01

403

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

404

Acidizing of Sandstone Reservoirs Using HF and Organic Acids  

E-print Network

Mud acid, which is composed of HCl and HF, is commonly used to remove the formation damage in sandstone reservoirs. However, many problems are associated with HCl, especially at high temperatures. Formic-HF acids have served as an alternative...

Yang, Fei

2012-10-19

405

McNeal field, Jasper County, Mississippi. A unique Jurassic oil accumulation  

Microsoft Academic Search

McNeal field is significant because it is a unique oil accumulation which is quite different from other Jurassic fields in the southeastern U.S. The productive zone is a Haynesville-Buckner Sand immediately overlying the Jurassic Haynesville-Buckner carbonate-evaporite sequence. The productive sand appears to be an offshore bar that separated the Jurassic carbonate-evaporite sea and the near-shore area of sand accumulation. Immediately

1975-01-01

406

Jurassic paleomagnetic constraints on the collision of the north and south China blocks  

Microsoft Academic Search

This paper reports a paleomagnetic study of Jurassic rocks from the Ordos Basin in the North China Block (NCB). A recent remagnetization and a high-temperature and\\/or high-coercivity component with dual polarities have been isolated. The Middle Jurassic pole (74°N, 233°E, A95=5°) is roughly consistent with previous results, and the Lower Jurassic pole (82°N, 286°E, A95=7°) is located between the late

Zhenyu Yang; Vincent Courtillot; Jean Besse; Xinghua Ma; Lisheng Xing; Shujin Xu; Jingxing Zhang

1992-01-01

407

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

408

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

409

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

410

Fault-fracture strain in Wingate Sandstone  

NASA Astrophysics Data System (ADS)

The Laramide deformation of the Triassic Wingate Sandstone along the northeast flank of the Uncompahgre uplift has occurred by faulting at various scales. Macroscopically smooth flexures of beds within the Wingate occur by small displacements across a myriad of intraformational, mesoscale faults. The deformation resultant from these small faults may be approximated by a strain tensor, provided the measurement domain satisfies certain size criteria. Equivalent strain (?) measurements, obtained from 22 locations in the East Kodel's Canyon, range from 1% to 15.5% (the maximum contractional strains range from -0.9% to -13.4%). The faults producing this strain have displacements ranging from a fraction of a millimeter to 18.5 cm. The fault intensity increases with increasing ?, although in a distinctly non-linear fashion. At low strains, incremental increases in the deformation produce additional, small displacement faults. At larger strains, incremental increases in the deformation occur via progressive displacement along existing faults. The principal strain axes are consistently non-coaxial with the inferred principal stresses (average ?1??1 is 18.5°). This non-coaxiality results from the non-uniform development of the conjugate fault systems. This same inequality of the conjugate systems produces a non-zero rotation tensor, ?, but ? is not related to ?1??1. The non-uniform development of conjugate shears (and the associated non-coaxiality of ?1 and ?1) may be an intrinsic characteristic of a Coulomb material.

Jamison, William R.

411

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.

412

Fractal measurements of sandstones, shales, and carbonates  

NASA Astrophysics Data System (ADS)

Measurements were made of the fractal properties of sandstones, shales, and carbonates using a statistical analysis of structural features on fracture surfaces. Fractal behavior is associated with power law behavior for the number of features as a function of the feature size on the pore-rock interface. Only one sedimentary rock, a novaculite, was found not to have a fractal structure. The fractal dimensions range from 2.27 to 2.89, and the long-length limits to the fractal regime range from 2 ?m to over 50 ?m. In all cases, the fractal behavior extends to less than 0.2 ?m which is the measurement resolution. The porosity associated with the fractal pore-rock interface can be calculated from the fractal parameters. Some of the samples have additional porosity not associated with power law behavior. Photographs and other evidence are used to show that the fractal structures are the result of diagenesis. Fractal diagenetic structures include euhedral quartz overgrowths, druse quartz, calcite, dolomite, clays, and chert.

Krohn, Christine E.

1988-04-01

413

Uranium migration through intact sandstone cores  

NASA Astrophysics Data System (ADS)

Uranium is often considered to be a mobile radioelement in the natural environment owing to its tendency to form stable complexes with a number of aqueous anions, particularly in oxidising milieu. A series of infiltration experiments were devised to investigate this migration behaviour under rigidly controlled laboratory conditions. Intact cores of Permo-Triassic Clashach Sandstone were pre-equilibrated with synthetic groundwater solutions and continuous flow-through of uranium monitored together with pH and concentrations of other ions. Prior to performing each experiment a simulation was carried out using a one-dimensional coupled chemical transport code, encompassing a thermodynamic description of the electrical double layer. These calculations together with electron microscopy indicated the potential role played by iron oxyhydroxide grain coatings in retarding the uranium plume. Thus, a second series of experiments was initiated on pre-acidified cores from which all surface exposed iron had been removed, allowing an assessment of the retention capacity of non-ferric components. Taken together, the data clearly illustrate the strong affinity of aqueous uranium species for natural surfaces even under strongly oxidising conditions. The success of the model in predicting a priori the dominant trends in uranium migration behaviour is encouraging and may aid in prioritising analytical requirements for investigations in more complex geochemical situations than those studied here.

Read, D.; Lawless, T. A.; Sims, R. J.; Butter, K. R.

1993-06-01

414

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

415

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

416

Development and Pilot Evaluation of Native CREST - a Cancer Research Experience and Student Training Program for Navajo Undergraduate Students  

PubMed Central

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 & 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 (5 females, 2 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.

2012-01-01

417

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

NASA Astrophysics Data System (ADS)

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

Dubey, N.; Bheemalingeswara, K.

2009-04-01

418

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

E-print Network

Jurassic­Cretaceous low paleolatitudes from the circum-Black Sea region (Crimea and Pontides) due in the present-day Black Sea region. Our Eurasian data suggest the same low Late Jurassic to Early Cretaceous

Utrecht, Universiteit

419

Olsen, P. E., 1986, Discoveryof earliest Jurassic reptile assemblage from Nova Scotia impliescatastrophicend to Triassic: Lamont (Newsletter),v. 12,p. 1-3. Discovery of Earliest Jurassic Reptile Assemblages from Nova Scotia  

E-print Network

Olsen, P. E., 1986, Discoveryof earliest Jurassic reptile assemblage from Nova Scotia impliescatastrophicend to Triassic: Lamont (Newsletter),v. 12,p. 1-3. Discovery of Earliest Jurassic Reptile Assemblages from Nova Scotia: Imply Catastrophic End to the Triassic LateTriassic and EarlyJurassic sediments

Olsen, Paul E.

420

Upper Jurassic of east Texas, a stratigraphic sedimentologic reevaluation  

SciTech Connect

The Smackover-Haynesville of east Texas has long been modeled as a simple progradational carbonate-evaporite ramp. Recent data indicate that the conventional ramp model for this sequence should be abandoned in favor of an evolving rimmed shelf to platform model, forming in response to changes in rate of relative sea level rise during the Late Jurassic. Evidence for Smackover-Haynesville shelves include: (1) thick high-energy carbonates along the basin margin in the Smackover and throughout the Haynesville, (2) low-energy pellet-dominated lagoonal carbonates, evaporites, and evaporitic siliciclastics occurring landward of, and interfingering with, the Smackover and Haynesville basin-margin carbonate barriers, (3) deeper water, open-marine low-energy limestones with black shales seaward of the basin-margin barriers (Smackover-Gilmer undifferentiated), and (4) the Gilmer shale forms a siliciclastic wedge seaward of the Haynesville basin margin and its zero isopach defines the Kimmeridgian shelf margin. The Smackover and Haynesville seem to represent 2 distinct sedimentologic cycles, with each cycle reflecting an initial relative sea level rise during which a rimmed shelf and lagoon are developed, and a terminal sea level standstill during which the shelf evolved into a high-energy platform. Although these sedimentologic patterns seem compatible with accepted Jurassic sea level curves, they may also reflect differential basin-margin subsidence combined with variable carbonate production rates. Finally, the shelf-platform model more clearly defines future exploration strategies for Smackover-Haynesville targets in east Texas and perhaps across the Gulf of Mexico, if eustatic sea level changes were the dominant causative factor for shelf development in the Late Jurassic.

Moore, C.H.; McGillis, K.; Stewart, S.; Wilkinson, S.; Harwood, G.

1985-02-01

421

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

422

Direct chemical evidence for eumelanin pigment from the Jurassic period.  

PubMed

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

2012-06-26

423

Inter-layered clay stacks in Jurassic shales  

NASA Technical Reports Server (NTRS)

Scanning electron microscopy in the backscattered electron mode is used together with energy-dispersive X-ray microanalysis to show that Lower Jurassic shales from the North Sea Basin contain large numbers of clay mineral stacks up to 150 microns in size. Polished shale sections are examined to determine the size, shape orientation, textural relationships, and internal compositional variations of the clays. Preliminary evidence that the clay stacks are authigenic, and may have formed at shallow burial depths during early diagenesis, is presented.

Pye, K.; Krinsley, D. H.

1983-01-01

424

Middle Jurassic fossils of the genus Sharasargus from Inner Mongolia, China (Diptera: Archisargidae)  

Microsoft Academic Search

To date, only two species of the genus Sharasargus are known. These Upper Jurassic species were found in Mongolia and Kazakhstan, respectively. We herein describe two new species from the Middle Jurassic, which were found in Inner Mongolia, China. They are the oldest known fossils of this genus. A key to Sharasargus species is given.

Kuiyan ZHANG; Ding YANG; Dong REN

2008-01-01

425

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

Microsoft Academic Search

Seismic and well data from the northeastern Gulf of Mexico were used to define the seismic stratigraphy, geologic history, and depositional setting of the Jurassic (Kimmeridgian) Haynesville sequence in the Apalachicola basin. The data show that Haynesville clastic sedimentation updip was coeval with Haynesville carbonate deposition downdip. The regional Jurassic seismic stratigraphic framework includes, in ascending order, the Louann Salt

L. M. Dobson; R. T. Buffler

1990-01-01

426

Evolution of the Apalachicola basin (northeastern Gulf of Mexico) during the Jurassic  

Microsoft Academic Search

A grid of multichannel seismic correlated with well data defines four Jurassic seismic sequences in the Apalachicola basin of the northeastern Gulf of Mexico. These sequences, which developed in response to basin architecture, sea level fluctuations, sediment supply, and salt movement document the depositional history of the basin during the Jurassic. Evaporation of water entering the basin resulted in deposition

L. M. Dobson; R. T. Buffler

1990-01-01

427

Magnetic polarity stratigraphy and paleolatitude of the Triassic^Jurassic Blomidon Formation in the Fundy basin  

E-print Network

Magnetic polarity stratigraphy and paleolatitude of the Triassic^Jurassic Blomidon Formation] characterized the Triassic as perhaps the most arid period of the Phanerozoic, citing evidence for widespread,5] and the apparent expan- sion of deserts in the Triassic and Early Jurassic to an extent not since repeated [6

Olsen, Paul E.

428

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

429

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

430

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

431

Development geology study of Weber sandstone, Rangely field, Colorado  

SciTech Connect

The Pennsylvanian-Permian Weber Sandstone formation is the major producing horizon at the giant Rangely field, Rio Blanco County, Colorado. The Weber has been separated into six lithofacies using core descriptions, core analyses, optical and scanning-electron microscopy, x-ray diffraction, and special-core analyses. Two of the lithofacies (eolian) are productive. The subarkosic laminated sandstones (which have the best reservoir quality) have an average Boyle's Law porosity of 9.7%. Permeability varies directionally on a small scale because of differential cementation within the graded laminae; the very fine-grained portion of the laminae is more tightly cemented by carbonate minerals than are the fine-grained portions. Permeability along the laminae averages 1.2 md; permeability across the laminae is less than 1 md. The second productive lithofacies is massive (bioturbated) and more thoroughly cemented than the first; it is also composed of fine and very fine-grained sandstones. These massive subarkosic sandstones have an average porosity of 7% and permeability averaging less than 1 md. Fractures alter permeability in portions of the field. The remaining four lithofacies (fluvial) are not productive and act as intraformational permeability barriers. Arkosic sandstones, arkosic siltstones, shales, and rare carbonates comprise this group. The relationship of the lithofacies to the depositional environment and the recognition of them on electric logs has allowed correlations across the field. This has proven an important contribution to the management of the current CO{sub 2} flood.

Jackson, W.D.; Bowker, K. (Chevron U.S.A. Inc., Houston, TX)

1989-09-01

432

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

433

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

434

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

435

Origin of high Zn contents in Jurassic limestone of the Jura mountain range and the Burgundy: evidence from Zn speciation  

E-print Network

Origin of high Zn contents in Jurassic limestone of the Jura mountain range and the Burgundy in Jurassic limestone of the Jura mountain range (JMR) and the Burgundy (B), we investigated four loca- tions of hydrothermal episodes. Keywords Zinc Á Cadmium Á Speciation Á Jurassic limestone Á Hydrothermalism 1

436

Strontium and carbon isotope stratigraphy of the Late Jurassic shallow marine limestone in western Palaeo-Pacific, northwest Borneo  

E-print Network

Strontium and carbon isotope stratigraphy of the Late Jurassic shallow marine limestone in western carbonate sec- tion within the Late Jurassic Bau Limestone at the SSF quarry in northwest Borneo, Malaysia Scotland and Russia, located in Boreal realm during the Late Jurassic. This suggests that either

Gilli, Adrian

437

Astronomically-calibrated magnetostratigraphy of the Lower Jurassic marine successions at St. Audrie's Bay and East Quantoxhead  

E-print Network

Astronomically-calibrated magnetostratigraphy of the Lower Jurassic marine successions at St in revised form 3 March 2014 Accepted 12 March 2014 Available online 21 March 2014 Keywords: Lower Jurassic these records can be accurately compared for consistency. The Lower Jurassic GPTS is however still poorly

Utrecht, Universiteit

438

Is the Jurassic (Yanshanian) intraplate tectonics of North China due to westward indentation of the North China Block?  

E-print Network

1 Is the Jurassic (Yanshanian) intraplate tectonics of North China due to westward indentation Jurassic-Early Cretaceous through three deformation phases coeval with syntectonic sedimentation, separated by two transtensional episodes coeval with magmatism. The Late Jurassic­Early Cretaceous tectonic event

Paris-Sud XI, Université de

439

Sea-water circulation on an oolite-dominated carbonate system in an epeiric sea (Middle Jurassic, Switzerland)  

E-print Network

Sea-water circulation on an oolite-dominated carbonate system in an epeiric sea (Middle Jurassic The Middle Jurassic Burgundy carbonate platform occupied a central part of the Central European Epeiric Sea during the Middle Jurassic. The facies architecture of the oolitic calcarenite bodies was affected

Gilli, Adrian

440

Seismic evidence for the presence of Jurassic oceanic crust in the1 central Gulf of Cadiz (SW Iberian margin)2  

E-print Network

Seismic evidence for the presence of Jurassic oceanic crust in the1 central Gulf of Cadiz (SW as a transform margin during the Early Jurassic that37 followed the continental break-up in the Central Atlantic40 spreading in the North Atlantic at the Tithonian (late Jurassic-earliest Cretaceous). The41

Paris-Sud XI, Université de

441

Olsen, et al., 2002 From: McRoberts, C. A. and Olsen, P. E., 2002, Triassic-Jurassic  

E-print Network

Olsen, et al., 2002 From: McRoberts, C. A. and Olsen, P. E., 2002, Triassic-Jurassic Non. #12;p. 13 ASTRONOMICALLY CALIBRATED GPTS FOR THE LATE TRIASSIC AND EARLY JURASSIC BASED ON THE NEWARK Timescale (GPTS) for the Triassic and Early Jurassic based on scientific coring of the Newark basin (NY, NJ

Olsen, Paul E.

442

PALEONTOLOGY AND PALEOENVIRONMENTS OF EARLY JURASSIC AGE STRATA IN THE WALTER KIDDE DINOSAUR PARK (NEW JERSEY, USA)  

E-print Network

REPRINT PALEONTOLOGY AND PALEOENVIRONMENTS OF EARLY JURASSIC AGE STRATA IN THE WALTER KIDDE OF EARLY JURASSIC AGE STRATA IN THE WALTER KIDDE DINOSAUR PARK (NEW JERSEY, USA) Paul E. Olsen Lamont is to provide an overview of the Jurassic age fossils from the site, and to place those remains

Olsen, Paul E.

443

TECTONICS,VOL. 11, NO. 4, PAGES823-835,AUGUST1992 UPPER JURASSIC-LOWER CRETACEOUS  

E-print Network

TECTONICS,VOL. 11, NO. 4, PAGES823-835,AUGUST1992 UPPER JURASSIC-LOWER CRETACEOUS BASINAL STRATA Jurassic-EarlyCretaceousevolutionof the Cordilleran margin.A geologicallyreasonablescenariofor the accretionof the AWP includes(1) Middle Jurassic accretionto the Cordilleranmargin,in particularthe Stikine

Jensen, Grant J.

444

Jurassic arc volcanism on Crimea (Ukraine): Implications for the paleo-subduction zone configuration of the Black Sea region  

E-print Network

Jurassic arc volcanism on Crimea (Ukraine): Implications for the paleo-subduction zone January 2010 Accepted 19 July 2010 Available online xxxx Keywords: Black Sea region Jurassic­Cretaceous 40 on the paleosubduction zone configuration of the southeastern European margin in the Jurassic, we report 40 Ar/39 Ar

Utrecht, Universiteit

445

Early Jurassic paleopoles from the Hartford continental rift basin (eastern North America): Was an abrupt change in polar  

E-print Network

Early Jurassic paleopoles from the Hartford continental rift basin (eastern North America biotic turnover at the Triassic/Jurassic boundary, adds impetus for seeking confirmation of possibly to reflect a major plate reorganization or an episode of true polar wander. However, early Jurassic

Olsen, Paul E.

446

Dinosaurs and other fossil vertebrates from the Late Jurassic and Early Cretaceous of the Galve area, NE Spain  

E-print Network

Dinosaurs and other fossil vertebrates from the Late Jurassic and Early Cretaceous of the Galve in an Upper Jurassic to Lower Cretaceous succession spanning some 30 myr, divided into five formations rights reserved. Keywords: Upper Jurassic­Lower Cretaceous; Galve; Spain; Vertebrate palaeontology

Benton, Michael

447

The Chachil Limestone (Pliensbachianeearliest Toarcian) Neuqun Basin, Argentina: UePb age calibration and its significance on the Early Jurassic  

E-print Network

calibration and its significance on the Early Jurassic evolution of southwestern Gondwana H.A. Leanza a,*, A Early Jurassic Chachil Limestone Precuyano Cycle Neuquén Basin a b s t r a c t New radiometric UePb ages obtained on zircon crystals from Early Jurassic ash layers found within beds of the Chachil Limestone

Mazzini, Adriano

448

Et-Touhami, et al., 2002 From: McRoberts, C. A. and Olsen, P. E., 2002, Triassic-Jurassic  

E-print Network

Et-Touhami, et al., 2002 From: McRoberts, C. A. and Olsen, P. E., 2002, Triassic-Jurassic Non MESOZOIC BASALT ERUPTION OVER MOROCCO IMMEDIATELY AFTER THE TRIASSIC-JURASSIC BOUNDARY. Mohammed Et similarities with each other, but also with sequences in the latest Triassic and earliest Jurassic of eastern

Olsen, Paul E.

449

PUBLISHED ONLINE: 13 JULY 2009 | DOI: 10.1038/NGEO577 Floral changes across the Triassic/Jurassic  

E-print Network

ARTICLES PUBLISHED ONLINE: 13 JULY 2009 | DOI: 10.1038/NGEO577 Floral changes across the Triassic/Jurassic occurred at the boundary of the Triassic and Jurassic periods, 201.6 million years ago. The loss of marine volcanism. Here we present pollen, spore and geochemical analyses across the Triassic/Jurassic boundary from

450

The Zedong terrane: a Late Jurassic intra-oceanic magmatic arc within the YarlungTsangpo suture zone, southeastern Tibet  

E-print Network

The Zedong terrane: a Late Jurassic intra-oceanic magmatic arc within the Yarlung­Tsangpo suture microprobe analyses reported here reveal that this arc was active during the Jurassic. U­ Pb dating of zircon belonged was active from at least Late Jurassic to Early to mid Cretaceous. D 2002 Published by Elsevier

Harrison, Mark

451

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

452

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

453

Diagenesis of the Oseberg Sandstone Reservoir (North Sea): An example of integration of core, formation fluid and geochemical modelling studies  

SciTech Connect

A detailed multidisciplinary integrated study of the Middle Jurassic Oseberg reservoir in 20 wells of the Oseberg field, Norwegian North Sea, was carried out in collaboration with Norsk Hydro and Oseberg partners. The objectives were to reconstruct the tinting, conditions and spatial variation of diagenetic transformations; to characterize the nature and origin of diagenetic fluids; and to develop a geochemical model of the observed diagenesis. The 20-60 m thick Oseberg Formation occurs at depths of 2.5 to 3.2 km, and at present temperatures of 100 to 125[degrees]C. The detrital assemblage is mainly composed of quartz, K-feldspar, albite, muscovite and lithic clay clasts, and is very homogeneous throughout the field. The diagenetic sequence includes: minor siderite and pyrite, K-feldspar rims, ankerite, pervasive feldspar dissolution, abundant vermiform kaolinite, quartz overgrowths, poikilotopic ferroan calcite, and dickite. Diagenetic temperatures were derived from fluid inclusions in ankerite, quartz and calcite, and combined with the modelled burial/thermal history to constrain approximate ages and duration of diagenetic events. Isotopic compositions of carbonates and kaolinite indicate that meteoric water and seawater were two major constituents of diagenetic fluids. Present formation waters are fairly similar chemically and isotopically at reservoir scale and represent mixing of three end members: seawater ([approximately]54%), meteoric water ([approximately]40%) and primary evaporative brine ([approximately]6%). Stability diagrams and chemical geothermometers indicate that formation fluids are close to equilibrium with the host sandstone at present reservoir temperatures.

Girard, J.P.; Sanjuan, B.; Czernichowski-Lauriol, I.; Fouillac, C. (BRGM, Orleans (France))

1996-01-01

454

Diagenesis of the Oseberg Sandstone Reservoir (North Sea): An example of integration of core, formation fluid and geochemical modelling studies  

SciTech Connect

A detailed multidisciplinary integrated study of the Middle Jurassic Oseberg reservoir in 20 wells of the Oseberg field, Norwegian North Sea, was carried out in collaboration with Norsk Hydro and Oseberg partners. The objectives were to reconstruct the tinting, conditions and spatial variation of diagenetic transformations; to characterize the nature and origin of diagenetic fluids; and to develop a geochemical model of the observed diagenesis. The 20-60 m thick Oseberg Formation occurs at depths of 2.5 to 3.2 km, and at present temperatures of 100 to 125{degrees}C. The detrital assemblage is mainly composed of quartz, K-feldspar, albite, muscovite and lithic clay clasts, and is very homogeneous throughout the field. The diagenetic sequence includes: minor siderite and pyrite, K-feldspar rims, ankerite, pervasive feldspar dissolution, abundant vermiform kaolinite, quartz overgrowths, poikilotopic ferroan calcite, and dickite. Diagenetic temperatures were derived from fluid inclusions in ankerite, quartz and calcite, and combined with the modelled burial/thermal history to constrain approximate ages and duration of diagenetic events. Isotopic compositions of carbonates and kaolinite indicate that meteoric water and seawater were two major constituents of diagenetic fluids. Present formation waters are fairly similar chemically and isotopically at reservoir scale and represent mixing of three end members: seawater ({approximately}54%), meteoric water ({approximately}40%) and primary evaporative brine ({approximately}6%). Stability diagrams and chemical geothermometers indicate that formation fluids are close to equilibrium with the host sandstone at present reservoir temperatures.

Girard, J.P.; Sanjuan, B.; Czernichowski-Lauriol, I.; Fouillac, C. [BRGM, Orleans (France)

1996-12-31

455

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

456

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

457

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

458

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

459

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

460

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

461

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

462

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 ...

Hoffmeister, Kathryn E

2011-08-31

463

Facies Description and Interpretation of the Upper Lower Hickory Sandstone, Riley Formation, Central Texas  

E-print Network

difficult. Based on core data and limited outcrops, the Lower Hickory Sandstone, a late Cambrian sandstone, has been interpreted to progress from fluvial to shallow marine. These data have allowed the development of an overall depositional model, but minimal...

Cook, Timothy D.

2010-01-16