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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

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

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

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

Microsoft Academic Search

The Upper Jurassic Hareelv Formation of Jameson Land, East Greenland, occurs in an area of 60 x 75 km. It consists of 200-500 m of black shale with thick, closely spaced sandstone bodies. The sandstones fill deep, steep-walled gullies and elongate scours, or form more regular, laterally extensive, parallel-sided, but erosive gully mouth or lobe deposits. Both types of sandstone

Surlyk

1987-01-01

5

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

USGS Publications Warehouse

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

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

1979-01-01

6

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

SciTech Connect

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

Surlyk, F.

1987-04-01

7

Reservoir petrology of analogous Middle Jurassic sandstones from Haltenbanken, Norway, and Jameson Land, east Greenland  

SciTech Connect

Stratigraphically equivalent Middle Jurassic sandstones from wells in the Haltenbanken area, offshore Norway, and outcrops in Jameson Land, east Greenland, are petrographically similar. Both are subarkosic and display similar diagenetic features, notably well-developed secondary porosity. The well-exposed Jurassic strata of east Greenland provided effective depositional and stratigraphic models for the prolific oil fields of the North Sea and Norwegian shelf, because sediments were deposited in closely related tectono-stratigraphic settings. Conversely, the productive Middle Jurassic sandstones of the North Sea and Norwegian shelf suggest analogous reservoirs should occur on the east Greenland shelf. Potential reservoir sandstones of east Greenland are moderately to well sorted and fine to medium grained, with porosity ranging from 10 to 30%. Much of the porosity is secondary, created by the dissolution of framework grains and carbonate cements. The pores are commonly oversize, elongated, and bridged by clusters of sutured quartz grains. Pore throats are large, suggesting high reservoir permeability. Two types of nonreservoir sandstones are observed: (1) slightly finer grained versions of the reservoir sandstones that are tightly cemented by up to 40 vol. % carbonate cement and smaller amounts of authigenic kaolinite, and (2) fine-grained sandstones rich in micrite lithic fragments (rip-ups) and detrital micas. The variation of porosity with grain size implies influence by original porosity and permeability that is ultimately controlled by depositional environment.

Cheatwood, C.J.; Mansfield, C.F.

1986-05-01

8

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

Microsoft Academic Search

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

Z. K. Shipton; P. A. Cowie

2001-01-01

9

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

10

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

11

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

NASA Astrophysics Data System (ADS)

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

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

2007-04-01

12

Depositional and compositional controls on sandstone diagenesis, the Tetori Group (Middle Jurassic Early Cretaceous), central Japan  

NASA Astrophysics Data System (ADS)

The Tetori Group is a representative Middle Jurassic to Lower Cretaceous deposit in the northern central part of Honshu, Japan. The Tetori Group is divided into the Kuzuryu, Itoshiro and Akaiwa Subgroups with decreasing age. It consists mainly of a marine sequence in the lower part (Kuzuryu Subgroup) and non-marine sequence in the upper part (Akaiwa Subgroup) with transitional sequence in the middle part (Itoshiro Subgroup). Diagenesis of Tetori Group sandstones comprises compaction, cementation and replacement. Early diagenetic events include mechanical compaction, and pore-filling cementation of calcite, siderite, dolomite and formation of kaolinite. Late diagenesis includes formation of quartz cement and albitization of feldspar, and formation of illite, chlorite, calcite, ankerite and pyrite. Among the diagenetic minerals, carbonate forms the major cement in Tetori Group sandstones. Calcite of each subgroup is subdivided into two or three types based on cathodoluminescence. Tetori Group sandstones of marine, fresh-water, and mixed depositional environments are characterized by distinct chemical compositions of early diagenetic calcites. Late diagenesis seems to have been mainly influenced by detrital compositions of the sequence, burial temperatures and partially hydrothermal processes. Especially, late diagenetic carbonate and authigenic clay minerals seem to have formed mainly from ions released from clay mineral transformations in the adjacent shales. Based on the illite crystallinity (IC), the Kuzuryu Subgroup exhibits higher diagenetic grades than the overlying Itoshiro and Akaiwa Subgroups, indicating that the diagenesis of the Tetori Group was mainly affected by depth of burial.

Kim, Jin Cheul; Lee, Yong Il; Hisada, Ken-Ichiro

2007-03-01

13

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

Microsoft Academic Search

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

Peter N. Johannessen

14

Petrography, diagenesis and pore-water evolution of a shallow marine sandstone (Hasle Formation, Lower Jurassic, Bornholm, Denmark)  

NASA Astrophysics Data System (ADS)

Lower Jurassic marine sandstones in the Hasle Formation on Bornholm Island can easily be separated in two different petrographic types. In the lower part of the type locality, type 1 sandstones are friable with layers and lenses of concretionary siderite. They are separated by a major erosional surface from the overlying type 2 well-cemented sandstones.All parts of the sandstones were subjected to chloritization of original grain coatings, neomorphism of chlorite and local precipitation of authigenic pyrite. During early diagenesis, diagenetic pathways differed between the two sandstone types. Type 1 sandstones were subjected to compaction before kaolinitization and some quartz authigenesis occurred. Type 2 sandstones immediately above the major erosional surface were cemented by concretionary siderite at a very early stage, and thus further diagenetic modifications were prevented. Above this zone, sandstones are tightly cemented by various carbonate minerals. Diagenetic modifications mainly involved alternating events of carbonate precipitation and dissolution. The sequence of carbonate precipitation was: (1) zoned stable/metastable siderite; (2) siderite, gradually with significant Ca- and Mg-substitution; (3) ankerite; and (4) calcite, reflecting a sequence of precipitating carbonates containing progressively lower amounts of iron. A period of kaolinitization predated calcite cementation.Six diagenetic stages were recognized: (1) early burial reducing conditions resulting in precipitation of pyrite; (2) precipitation of chlorite and siderite caused from compactional flow from underlying brackish and fresh-water sediments; (3) dissolution of carbonate and partly oxidation of siderite caused by fresh-water flushing related to uplift; (4) precipitation of siderite with gradually increasing substitution by CaCO3 and MgCO3 and eventually precipitation of ankerite caused by renewed burial; (5) fresh-water diagenesis with precipitation of kaolinite and quartz; (6) precipitation of calcite in remnant porosity.

Larsen, Ole Hede; Friis, Henrik

1991-08-01

15

Paleomagnetic and rock magnetic evidence for a secondary yet early magnetization in large sandstone pipes and host Late Middle Jurassic (Callovian) Summerville Formation and Bluff Sandstone near Mesita, west central New Mexico  

Microsoft Academic Search

Processes responsible for the acquisition of ancient yet secondary magnetizations are important facets of the geologic history of rocks and, when the age of such magnetizations can be estimated with confidence, provide useful information on the ancient geomagnetic field. In west central New Mexico near Mesita, on the Colorado Plateau, hematitic sandstone and siltstone beds of the Middle Jurassic (Callovian)

John W. Geissman; Stephen S. Harlan

2004-01-01

16

Provenance of fluvial sandstones at the start of late Jurassic Early Cretaceous rifting in the Cameros Basin (N. Spain)  

NASA Astrophysics Data System (ADS)

The Cameros Basin (Iberian Chain, Central Spain) developed during the latest Jurassic Early Cretaceous in an extensional regime characterized by high rates of subsidence. Its sedimentary fill has been subdivided into eight depositional sequences (DS) mainly composed of continental sediments. DS 1 and DS 2 represent the first rifting stage (Tera Group, Tithonian). The purpose of this study is to characterize the Tera Group in the eastern part of the basin based on provenance criteria derived from fluvial sandstones. In this area of the basin, the Tera Group can be subdivided into three formations: the Ágreda Formation, the Magaña Formation and the Sierra de Matute Formation. These formations are composed of alluvial-fan deposits, meandering fluvial sediments and lacustrine palustrine mudstones. A quantitative petrographic study indicated the presence of three main petrofacies in the Tera Group. The close correlation between petrofacies and lithostratigraphic units indicates that sandstone composition is a powerful tool for deciphering the tectonic processes active during the initial rift stages of the Cameros Basin. Petrofacies 1 is sedimentolithic (mean: Qm54F3Lt43) and represents erosion of the Jurassic marine pre-rift substratum (mainly Kimmeridgian limestones) during deposition of the DS 1 alluvial fan deposits (Ágreda Fm.). Petrofacies 2 is quartzofeldspathic, and can be subdivided into Petrofacies 2A, with an average composition of Qm84F15Lt1 and Petrofacies 2B, whose average composition is Q71F23Lt6. Petrofacies 2 was generated by the erosion of low to medium-grade metamorphic terranes and plutonic source rocks. It characterizes the Magaña Fm. (DS 2). Petrofacies 3 is quartzolithic (mean: Qm67F16Lt17), and is attributed to tectonic reactivation of the basin. This petrofacies characterizes the Sierra de Matute Fm. (DS 2). Thus, the provenance evolution of this basin is characterized by erosion of the pre-rift sedimentary substratum, followed by unroofing of the basement, as recorded in other ancient and modern rifted basins.

González-Acebrón, Laura; Arribas, José; Mas, Ramón

2007-11-01

17

Using geochemical techniques to identify salinity sources in the freshwater Navajo aquifer, Aneth Oil Field, Utah  

SciTech Connect

The salinity of water in the Triassic and Jurassic Navajo Sandstone in southeastern Utah has increased locally since 1952. The Navajo aquifer, within the Navajo Sandstone, is major source of water for domestic use and livestock in the area. From 1989 to 1991, concentration of dissolved solids in one well increased by as much as 5500 mg/L. The source or sources of the saline water and the reasons for the local increases are not known; however, mixing with either oil-field brines (OFB) or non-oil-field brines (NOFB) from the Pennsylvanian Paradox Formation could possibly cause the increase salinity. One of the objectives of an ongoing study is to use end-member mixing models and step-wise discriminant analysis to determine the possible source or sources of saline water causing the observed increase in salinity in the Navajo aquifer. Discriminant analysis was used on the major-ion/chloride ratios to identify saline-water sources that could have mixed with Navajo aquifer water.

Nafiz, D.L.; Spangler, L.E. (Geological Survey, Salt Lake City, UT (United States))

1993-08-01

18

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

SciTech Connect

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

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

1996-03-01

19

Oevre jurassiske sandstensreservoirer i Det Danske Central Trug. Afsluttende rapportering til Energiministeriet. (Upper jurassic sandstone reservoirs in the Danish Central Trough. Final report addressed to the Ministry of Energy).  

National Technical Information Service (NTIS)

This final report addressed to the Danish Ministry of Energy concerns a project on the upper Jurassic sandstone reservoirs in the Danish Central Trough. The aim was to set up a dynamic, geological model of the development of the Jurassic Basin in the nort...

P. N. Johannessen K. Dybkjaer E. Skovbjerg Rasmussen

1992-01-01

20

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

SciTech Connect

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

Girard, J.P.; Sanjuan, B.; Fouillac, C. [BRGM, Orleans (France)] [and others

1995-08-01

21

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

Microsoft Academic Search

Norphlet sandstones in seven cores from Mississippi and Alabama are arkoses and subarkoses deposited in eolian-dune, interdune, and fluvial environments. Similar to the deeply buried (> 5 km) Tertiary feldspathic sandstones of the Gulf basin, all detrital plagioclase that survived dissolution has been albitized. Fluvial red sandstone lost all initial porosity by the introduction of preburial pedogenic calcite and compaction.

L. S. Land; L. E. Mack

1987-01-01

22

Paleomagnetic and rock magnetic evidence for a secondary yet early magnetization in large sandstone pipes and host Late Middle Jurassic (Callovian) Summerville Formation and Bluff Sandstone near Mesita, west central New Mexico  

NASA Astrophysics Data System (ADS)

Processes responsible for the acquisition of ancient yet secondary magnetizations are important facets of the geologic history of rocks and, when the age of such magnetizations can be estimated with confidence, provide useful information on the ancient geomagnetic field. In west central New Mexico near Mesita, on the Colorado Plateau, hematitic sandstone and siltstone beds of the Middle Jurassic (Callovian) Summerville Formation and overlying Bluff Sandstone are host to numerous large (up to 100 m2 in map area) pipe-like sandstone bodies. The pipes are as strongly cemented by hematite (colors range from 10R 6/6 to 10R 3/4) as the host strata; paleomagnetic data from them and their host strata are interpreted to indicate that these rocks have been remagnetized, probably in association with sandstone pipe formation. Reverse polarity magnetizations isolated in both alternating field and thermal demagnetization from pipes are well grouped and are similar to, and not statistically distinct from, those in adjacent host strata. The grand-mean direction for 16 sites (7 sites in sandstone pipes and 9 in host strata), corrected for slight (5°) west-northwest tilt of the strata, is D = 163.0°, I = -44.3° (?95 = 2.7°, k = 169). This direction yields a pole position of 72.8°N, 135.7°E (dp = 2.1°, dm = 3.4°). Assuming a modest (i.e., ˜5°) clockwise rotation of the Colorado Plateau, the pole lies at 68.7°N, 143.8°E. Median destructive fields for the remanence in pipes and host strata are typically 40-50 mT; over 90% of the remanence is "unblocked" or removed during changes in the magnetic mineralogy by temperatures of ˜400-450°C. Isothermal remanent magnetization (IRM) acquisition data, and thermal demagnetization of "saturation" IRM, however, demonstrate that the dominant magnetic phase is of high coercivity and relatively high (above 600°C) laboratory unblocking temperatures in both sandstone pipes and host strata, yet it does not appear to contribute significantly to the characteristic remanent magnetization. The similarity in demagnetization properties between pipes and adjacent host strata, the absence of a well-defined high unblocking temperature remanence that is more typical of hematite-cemented detrital strata, and the essentially uniform reverse polarity of the remanence are all interpreted to indicate that pipes and host strata contain secondary, yet early acquired magnetizations and that magnetization acquisition continued after pipe injection. We propose that acquisition of the secondary magnetization took place in the presence of alkaline, high pH brines formed by the dissolution of the underlying gypsum-dominated Lower Jurassic Todilto Formation strata and therefore the remanence is early in age. On the basis of a comparison with Summerville and Morrison (Middle and Late Jurassic) paleomagnetic poles from rocks on the Colorado Plateau, we interpret the secondary remanence in Summerville strata and sandstone pipes near Laguna to be latest Middle to Late Jurassic in age. If realistic, this interpretation further emphasizes the importance of fluid-rock interaction in the acquisition of secondary magnetizations.

Geissman, John W.; Harlan, Stephen S.

2004-07-01

23

THE NAVAJOS.  

ERIC Educational Resources Information Center

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

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

24

THE NAVAJOS.  

ERIC Educational Resources Information Center

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

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

25

Mixing zone origin of 13 C-depleted calcite cement: Oseberg Formation sandstones (Middle Jurassic), Veslefrikk Field, Norway  

Microsoft Academic Search

Carbonate cement is one of the more volumetrically important diagenetic components of sandstones. The sandstones of the fan delta facies of the Oseberg Formation (Brent Group) in Veslefrikk field contain abundant carbonate cemented zones, commonly comprised of 30-40% carbonate by volume. The cement is predominantly poikilotopic, ferroan calcite, with minor amounts of ankerite and siderite. Petrographie evidence for high porosities

Paul D. Lundegard

1994-01-01

26

Middle to Late Jurassic basin evolution and sandstone reservoir distribution in the Danish Central Trough. A contribution to the EFP-90 project: Upper Jurassic sandstone reservoirs in the Danish Central Trough.  

National Technical Information Service (NTIS)

During the Middle and Late Jurassic, long-term eustatic sea-level rise and halfgraben subsidence in the Danish Central Trough resulted in a major transgression. Deposition of widespread alluvial plain sediments in the Soegne Basin and Tail End Graben was ...

P. N. Johannessen J. Andsbjerg

1992-01-01

27

Navajo Justice.  

ERIC Educational Resources Information Center

|The Navajo Nation has eliminated jail time for 79 offenses and required traditional peacemaking in criminal cases, primarily involving family violence. Peacemaking entails examination of the criminal act by all involved, family responsibility for its members, and symbolic restitution. The change promotes prevention and child protection by…

Yazzie, Robert

2000-01-01

28

Mixing zone origin of 13 C-depleted calcite cement: Oseberg Formation sandstones (Middle Jurassic), Veslefrikk Field, Norway  

NASA Astrophysics Data System (ADS)

Carbonate cement is one of the more volumetrically important diagenetic components of sandstones. The sandstones of the fan delta facies of the Oseberg Formation (Brent Group) in Veslefrikk field contain abundant carbonate cemented zones, commonly comprised of 30-40% carbonate by volume. The cement is predominantly poikilotopic, ferroan calcite, with minor amounts of ankerite and siderite. Petrographie evidence for high porosities at the time of calcite precipitation indicate that cementation occurred under shallow burial conditions, probably less than 500 m. Crosscutting textural relations demonstrate that calcite cementation was predated and postdated by tectonic stresses that produced both grain fractures and through-going fractures, respectively. In the non-calcite cemented parts of the formation major compaction, pressure solution, feldspar dissolution, and cementation by quartz and clays postdated calcite cementation. The oxygen isotopic composition of the calcite averages - 8.5% 0 (PDB), and shows large variations within individual calcite cemented zones (up to 10% 0 in 18 O). The depleted and variable oxygen isotopic composition, in conjunction with evidence for shallow precipitation, indicate calcite growth occurred in a mixing zone environment, variably influenced by meteoric water. Isotopic variation within many individual cemented zones is symmetric about the center of the zones, indicating that growth of the cemented zones was from the center outwards in a concretionary fashion. The high Fe and Mn content of the calcite (avg. 1.3 mol% Fe, avg. 0.4 mol% Mn) and its association with disseminated pyrite indicate that porewater was reducing during precipitation. Carbon isotopic data (avg. 13 C = - 15.7% 0 PDB, RANGE = - 3 to - 3 1% 0 ) show that major amounts of organic carbon, at least partly derived by sulfate reduction of biogenic methane, were incorporated in the calcite. Other documented occurrences of early, 13 C-depleted carbonate-cemented sandstones are similar to the carbonate cement in Veslefrikk Field in their association with methane oxidation and their low temperature formation. However, the cement at Veslefrikk differs in its mineralogical and morphological occurrence and in the fact that it formed from a porewater strongly influenced by mixing with meteoric water. Key geologic factors that determined the traits of calcite cement in Veslefrikk Field are the combination of nearshore marine deposition of permeable sands, close proximity of organic-rich marine muds, and variations in relative sea level, which provided opportunities for invasion by meteoric water. These geologic factors had a similar impact on other Brent Group deltaic sandstones and are believed to explain some of the differences between the geochemistry of carbonate cements in deltaic and shelf sandstones of the North Sea and elsewhere.

Lundegard, Paul D.

1994-06-01

29

Triassic and Jurassic rocks at Currie, Nevada Preliminary paleontologic evidence  

SciTech Connect

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

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

1993-04-01

30

Geology Fieldnotes: Navajo National Monument, Arizona  

NSDL National Science Digital Library

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

31

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

32

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

National Technical Information Service (NTIS)

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

P. L. Hansley

1990-01-01

33

Annual monsoon rains recorded by Jurassic dunes.  

PubMed

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

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

2001-07-01

34

Strong Navajo marriages.  

PubMed

The purpose of this qualitative study, conducted in two Navajo Nation chapters, was to learn what makes Navajo marriages strong because no research has been done on this topic. Twenty-one Navajo couples (42 individuals) who felt they had strong marriages volunteered to participate in the study. Couples identified the following marital strengths: (1) maintain communication, (2) nurture your relationship, (3) learn about marriage, (4) be prepared for marriage, and (5) have a strong foundation. PMID:19085828

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

2008-01-01

35

Lacustrine strata of early Jurassic age, Hartford and Deerfield rift basins, Massachusetts and Connecticut: Deposition, maturation of black mudstones, sandstone diagenesis, and hydrocarbon occurrences  

SciTech Connect

Lacustrine cycles occur in the 100-m Shuttle Meadow, 170-m East Berlin, and lower part of the 1,200-m Portland Formations in the Hartford basin and in the 600-m Turners Falls Sandstone in the Deerfield basin. Eleven exposed cycles range in thickness from 3 to 10 m. Black mudstones are mostly 1-2 m thick, deposited in the deeper parts of oligomictic perennial lakes. Gray sandstones accumulated on delta lobes, fan deltas, and from sheetfloods that spread across the valley floor to cover exposed lacustrine littoral muds. Both rift-basin fills are dominated by alluvial-fan, fluvial, and playa red beds. The lacustrine sandstones are arkoses and lithic arkoses (72 modal analyses). Omitting minor cements, diagenetic events are (1) compaction, (2) quartz and albite overgrowths with albitization of detrital plagioclase, (3) dolomite and ferroan dolomite cements, and (4) hydrocarbon migration with creation of secondary porosity. Consistently large intergranular volumes in the lacustrine sandstones, as high as 40%, suggest that cementation began prior to significant compaction. Porosity in the sandstones ranges from 0 to 11%, averaging 2%. Organic geochemical data for black mudstones in the East Berlin, Portland, and Turners Falls Formations, combined with published and USGS open-file data, show that organic richness and oil proneness increase southward in the Hartford basin whereas thermal maturity increases northward. Oil generation has occurred in the East Berlin Formation, as evidenced by relatively large amounts of extractable bitumen, high-molecular-weight hydrocarbons, and hydrocarbons present in the sandstones. The Deerfield basin is overmature for oil.

Meriney, P.E.; Hubert, J.F.; Smith, M.A.

1988-08-01

36

Our Friends -- The Navajos.  

ERIC Educational Resources Information Center

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

Navajo Community Coll. Press, Tsaile, AZ.

37

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

38

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

Microsoft Academic Search

We incorporate field investigations and analytical techniques to reconstruct vent geometry and evolution, magma\\/water ratio, zone of fragmentation and efficiency of fragmentation of a mid-Tertiary phreatomagmatic eruption. Narbona Pass maar, located in the Chuska Mountains of northwest New Mexico, is a center in the (28-19 Ma) Navajo Volcanic Field. Minette magma erupted through a sandstone aquifer approximately 25 Ma (Cather

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

2005-01-01

39

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

40

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

ERIC Educational Resources Information Center

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

Norton, Katie Jebb

41

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

42

Navajo Stories of the Long Walk Period.  

ERIC Educational Resources Information Center

Presented by Navajo narrators for the Navajo people, this collection of stories reflects the Navajo perception of Navajo history and the "Long Walk" to Fort Sumner, emphasizing Navajo insight rather than historical events placed in chronological sequence. Collectively, these 40 stories reflect the following Navajo perceptions: events recalled in…

Johnson, Broderick H., Ed.

43

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.

44

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.

45

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

46

Permeability patterns in some fluvial sandstones. An outcrop study from Yorkshire, North East England.  

National Technical Information Service (NTIS)

The distribution of permeability in some fluvial sandbodies (lenticular bedded sheet sandstone, lateral accretion-bedded sandstone and crevasse splay complex) in The Middle Jurassic Scalby Formation was measured on two-dimensional outcrops with a miniperm...

T. Jacobsen H. Rendall

1989-01-01

47

Reevaluation of upper Jurassic Morrison Formation, Western Interior  

Microsoft Academic Search

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

Mantzios

1989-01-01

48

The poetics and politics of Navajo ideophony in contemporary Navajo poetry  

Microsoft Academic Search

This article describes aspects of Navajo sound symbolism within its social and political contexts. Specifically, it focuses on the use of Navajo ideophony. Examples of Navajo ideophony are presented from a variety of verbal and written genres including song, narrative, place-names, and contemporary written poetry. It is argued that Navajo ideophony is an important poetic device in Navajo aesthetics and

Anthony K. Webster

2009-01-01

49

Focus on Navajo Tribal Government.  

ERIC Educational Resources Information Center

Navajo Tribal Government is explained in a booklet for ninth grade civics students. The booklet emphasizes basic information drawn from the Navajo Tribal Code and includes a pre-post test and teacher, group and individual activities which stress finding, organizing, and communicating information. The three branches of tribal…

Pacheco, Sylvia

50

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.

51

NAVAJO NATION HAZARDOUS WASTE SITES  

EPA Science Inventory

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

52

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

53

Navajo Coal: Demands, Attitudes, and Environment.  

ERIC Educational Resources Information Center

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

Goodman, James M.

54

Depressive illness and Navajo healing.  

PubMed

What is the experience of Navajo patients in Navajo religious healing who, by the criteria and in the vernacular of contemporary psychiatry, would be diagnosed with the disorder called depression? We ask this question in the context of a double dialogue between psychiatry and anthropology and between these disciplines' academic constructs of illness and those of contemporary Navajos. The dialogue is conducted in the arena of patient narratives, providing a means for observing and explicating processes of therapeutic change in individuals, for illustrating variations in forms of Navajo religious healing sought out by patients demonstrating similar symptoms of distress, and for considering the heuristic utility of psychiatric diagnoses and nomenclature in the conceptualization of illness, recovery, and religious healing. From among the 37 percent of patients participating in the Navajo Healing Project who had a lifetime history of a major depressive illness, three are discussed herein, their selection based on two criteria: (1) all met formal psychiatric diagnostic criteria for a major depressive episode at the time of their healing ceremonies, and (2) together, their experiences illustrate the range of contemporary Navajo religious healing, including Traditional, Native American Church (NAC), and Christian forms. We suggest that, despite the explicit role of the sacred in religious healing interventions available to Navajo patients, differences between biomedical and religious healing systems may be of less significance than their shared existential engagement of problems such as those glossed as depression. PMID:11224981

Storck, M; Csordas, T J; Strauss, M

2000-12-01

55

Navajo Opposition to the Indian New Deal.  

ERIC Educational Resources Information Center

|Examines how the livestock reduction plan enforced by the Federal government in the 1930s resulted in drastically negative ecological, economic, and health consequences for the Navajo people. Describes manifestations of Navajo criticism and resistance. (GC)|

Grinde, Donald A., Jr.

1981-01-01

56

Novel nano-organisms from Australian sandstones  

Microsoft Academic Search

We report the detection of living colonies of nano-organisms (nanobes) on Triassic and Jurassic sandstones and other substrates. Nanobes have cellular structures that are strikingly similar in morphology to Actinomycetes and fungi (spores, filaments, and fruiting bodies) with the exception that they are up to 10 times smaller in diameter (20 nm to 1.0 mm). Nanobes are noncrystalline structures that

PHILIPPA J. R. UWINS; RICHARD I. WEBB; ANTHONY P. TAYLOR

1998-01-01

57

The Origins of Navajo Youth Gangs.  

ERIC Educational Resources Information Center

|Extended interviews with 50 Navajo men, aged 21 to 45, provided information on peer relationships and gang formation among male Navajo youth in the 1960s through the 1980s. Results suggest that gangs are an extreme example of traditional hell-raising among young Navajo men and that most gang members "age out" of their gangs. Suggestions for gang…

Henderson, Eric; Kunitz, Stephen J.; Levy, Jerrold E.

1999-01-01

58

Sandstone Reservoirs  

Microsoft Academic Search

The Rocky Mountain province of the United States contains structural and stratigraphic traps from which petroleum is produced from all types of sandstone reservoirs ranging in age from Cambrian to the Eocene. Three large typical stratigraphic traps in this province, where reservoirs are of Cretaceous age, are described. The Cut Bank Field, Montana produces from aluvial point bar sandstones; Patrick

Robert Weimer; R. W. Tillman

1982-01-01

59

Social services: the Navajo way.  

PubMed

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

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

60

Composition, porosity, and reservoir potential of the Middle Jurassic Kashafrud Formation, northeast Iran  

Microsoft Academic Search

In the Kopet-Dagh Basin of Iran, deep-sea sandstones and shales of the Middle Jurassic Kashafrud Formation are disconformably overlain by hydrocarbon-bearing carbonates of Upper Jurassic and Cretaceous age. To explore the reservoir potential of the sandstones, we studied their burial history using more than 500 thin sections, supplemented by heavy mineral analysis, microprobe analysis, porosity and permeability determination, and vitrinite

Mehdi Reza Poursoltani; Martin R. Gibling

2011-01-01

61

Tough Issues for Navajo Youth and Navajo Schools. Draft.  

ERIC Educational Resources Information Center

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

Trotter, Robert T., II; And Others

62

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.

63

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

64

The Navajo 10 Year Plan.  

ERIC Educational Resources Information Center

For over a hundred years the federal government has been underfunding its treaty obligations and other commitments to the Navajos. As a result, much of the reservation economy now operates at the level of bare subsistence. Deficiencies in social overhead capital have brought on even more marked deficiencies in industrial and commercial capital.…

Navajo Tribe, Window Rock, AZ.

65

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

66

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

67

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

68

Navajo Project, Arizona. Appendix 1.  

National Technical Information Service (NTIS)

The document is an appendix to a previous volume of the same title. It contains copies of comments received by the Bureau of Reclamation on the September 1971 Draft Environmental Statement, Navajo Project. Copies of attachments to the original letters or ...

1972-01-01

69

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.

70

A dinosaur ichnocoenosis from the middle jurassic of Yorkshire, UK  

Microsoft Academic Search

An assemblage of dinosaur tracks from the undersurface of a sandstone bed in the Saltwick Formation (Middle Jurassic) of Yorkshire shows a range of morphological types, preservational variants and behavioral styles. The tracks are combinations of transmitted prints and underprints and include three distinct trackways. One trackway was made by an animal walking on exposed damp sand, another was left

M. A. Whyte; M. Romano

2001-01-01

71

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.

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

1995-01-01

72

Teacher-Aide Guide for Navajo Area.  

ERIC Educational Resources Information Center

Results of a 1970 teacher and Navajo aide workshop, sponsored by the Navajo Area Division of Education, are compiled in this guide developed particularly for use by those who work with Indian students. Workshop curriculum content and objectives are provided, as well as a section on role identification for teacher/aide teams; checklists concerning…

Dzilth-Na-O-Dith-Hle Boarding School, Bloomfield, NM.

73

Cross Cultural Learning with the Navajo.  

ERIC Educational Resources Information Center

Describes the final segment of a Seattle high school anthropology course--a four-week stay on the Navajo Reservation. Examines how this immersion in Navajo culture changed the values and perspectives of White students as they were forced to confront paradoxes in their own lives. (SV)

Luckmann, Charles

1989-01-01

74

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

75

"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.

76

Porosity prediction in sandstones using erosional unconformities  

SciTech Connect

Erosional unconformities of subaerial origin are created by tectonic uplifts and eustatic sea level fall. Most erosional unconformities developed on sandstones are planes of increased porosity because uplifted sandstones are exposed to undersaturated CO/sub 2/-charged meteoric waters that result in dissolution of unstable framework grains and cements. The chemical weathering of sandstones is intensified in humid regions by heavy rainfall, lush vegetation, soil zones, and the voluminous production of inorganic and organic acids. Erosional unconformities are considered hydrologically open systems because of abundant supply of fresh meteoric water and relatively unrestricted transport of dissolved constituents away from the site of dissolution. Thus, porosity in sandstones commonly increases toward overlying unconformities. Empirical models have been developed on the basis of the observed relationship between erosional unconformities and porosity in the underlying sandstones in the North Sea (Middle Jurassic Brent Group) and in the Alaskan North Slope (Triassic Ivishak Formation). An important practical attribute of these models is that they allow for the prediction of porosity in frontier areas by recognizing erosional unconformities in seismic reflection profiles and by constructing subcrop maps for underlying sandstones. Hydrocarbon-bearing sandstone reservoirs in Alaska, Algeria, Australia, China, Libya, Netherlands, North Sea, Norwegian Sea, and Texas occur immediately beneath major erosional unconformities.

Shanmugam, G.

1988-01-01

77

Porosity prediction in sandstones using erosional unconformities  

SciTech Connect

Erosional unconformities of subaerial origin are created by tectonic uplifts and eustatic sea level fall. Most erosional unconformities developed on sandstones are planes of increased porosity because uplifted sandstones are exposed to undersaturated CO/sub 2/-charged meteoric waters that result in dissolution of unstable framework grains and cements. The chemical weathering of sandstones is intensified in humid regions by heavy rainfall, lush vegetation, soil zones, and the voluminous production of inorganic and organic acids. Erosional unconformities are considered hydrologically open systems because of abundant supply of fresh meteoric water and relatively unrestricted transport of dissolved constituents away from the site of dissolution. Thus, porosity in sandstones commonly increases toward overlying unconformities. Empirical models have been developed on the basis of the observed relationship between erosional unconformities and porosity in the underlying sandstones in the North Sea (Middle Jurassic Brent Group) and in the Alaskan North Slope (Triassic Ivishak Formation). An important practical attribute of these models is that they allow for the prediction of porosity in frontier areas by recognizing erosional unconformities in seismic reflection profiles and by constructing subcrop maps for underlying sandstones. Hydrocarbon-bearing sandstone reservoirs in Alaska, Algeria, Australia, China, Libya, Netherlands, North Sea, Norwegian Sea, and Texas occur immediately beneath major erosional unconformities.

Shanmugam, G.

1988-02-01

78

Family Planning Attitudes of Traditional and Acculturated Navajo Indians.  

ERIC Educational Resources Information Center

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

Ackerman, Alan; And Others

79

Geohydrologic data from sandstone aquifers in southwestern Kansas  

USGS Publications Warehouse

Data collected during a reconnaissance investigation of the geology and hydrology of sandstone aquifers provide useful information in the study of, and planning for, water-resources development in a 17,400 square-mile area in 26 counties of southwestern Kansas. The aquifers consist chiefly of saturated sandstones that occur in Upper Permian, Upper Jurassic, and Lower and Upper Cretaceous rocks. In parts of southwestern Kansas, the sandstone aquifers already serve as the principal or secondary source of ground water for irrigation and other uses. Data indicate that water may be available for development in sandstone aquifers in other parts of the study area. In still other areas, water from wells in sandstone aquifers may not be of a suitable quality for some purposes. The data provided include records of selected wells, lithologic logs of test holes and wells, selected formation surfaces and sandstone thicknesses , chemical analyses of water from selected wells, and water levels in observation wells. (USGS)

Kume, Jack; Spinazola, Joseph M.

1982-01-01

80

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

81

Global Jurassic tetrapod biochronology  

Microsoft Academic Search

Jurassic tetrapod fossils are known from all of the continents, and their distribution documents a critical paleobiogeographic juncture in tetrapod evolution - the change from cosmopolitan Pangean tetrapod faunas to the provincialized faunas that characterize the late Mesozoic and Cenozoic. Two global tetrapod biochronological units (faunachrons) have been named for the Early Jurassic - Wassonian and Dawan - and reflect

Spencer G. LUCAS

82

Black shales of Jurassic Newark basin  

SciTech Connect

Rock cores have exposed the complete Jurassic section of the Newark basin, including three sedimentary formations of fluvial origin. Within the Feltville, Towaco, and Boonton formations, 16 lacustrine/fan units range in thickness from 1 to 15 m. Each unit contains one black shale facies, although lower units of the Towaco contain multiple fining-upward sequences ending with truncated deep-water shale. Additional thinner gray sandstone facies in each formation occur at the margin of lacustrine units located farther southwest, in the paleodrainage direction of the Newark basin. Most microlaminated black shale shows evidence of turbidity flows. Freshly broken pieces of black shale and adjacent sandstones also have a strong organic odor.

Fedosh, M.S.

1986-05-01

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

Pure and shear-enhanced compaction bands in Aztec Sandstone  

Microsoft Academic Search

We report on the occurrence of deformation bands in Jurassic eolian Aztec Sandstone at Valley of Fire, Nevada, that accommodated roughly equal amounts of shear and band-perpendicular compaction by grain rearrangement and porosity collapse. These bands, referred to as shear-enhanced compaction bands, differ in orientation, structural arrangement, and microtexture from pure compaction bands that form perpendicular to the shortening direction.

Peter Eichhubl; John N. Hooker; Stephen E. Laubach

2010-01-01

85

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

Microsoft Academic Search

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

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

2005-01-01

86

Porosity prediction in sandstones using erosional unconformities  

SciTech Connect

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

Shanmugam, G.

1989-03-01

87

Navajo Generating Station Ecological Baseline Studies.  

National Technical Information Service (NTIS)

A six year study of the probable environmental impact of electric generating stations (the Navajo Generating Station under construction and the planned Kaiparowits Generating Station) in the Kaiparowits Basin was initiated. There were three main objective...

W. S. Gaud D. W. Blinn J. S. States R. H. Hevlyn W. L. Lipke

1972-01-01

88

Kinaalda: The Pathway to Navajo Womanhood.  

ERIC Educational Resources Information Center

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

Ryan, Danita Begay

1988-01-01

89

Kinaalda: The Pathway to Navajo Womanhood.  

ERIC Educational Resources Information Center

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

Ryan, Danita Begay

1988-01-01

90

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;…

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

91

The Müller-Lyer Illusion among Navajos  

Microsoft Academic Search

The hypothesis was tested that people within the same culture who live in a noncarpentered environment would be less susceptible to the Müller-Lyer illusion than those in a carpentered environment. Ten Navajo Ss who had lived at least the first six years of their lives in a Hogan—the traditional Navajo round house—and 10 Ss who had lived all of their

Darhl M. Pedersen; John Wheeler

1983-01-01

92

The Story of the Navajo Treaties. Navajo Historical Publications, Documentary Series No. 1.  

ERIC Educational Resources Information Center

|Navajo peace treaties are reproduced and the conditions discussed in this historical document. Knowledge of peace treaties between the Navajos and Spanish in the 17th and 18th centuries is fragmentary. The first known treaty known treaty with Spain is dated May 12, 1805. Following this treaty came further treaties with Spain, between 1805-19;…

Brugge, David M.; Correll, J. Lee

93

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

94

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.

95

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

96

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

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

97

Kemik sandstone: inner shelf sand from northeast Alaska  

SciTech Connect

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

Melvin, J.

1986-05-01

98

Historic Navajo Occupation of the Northern Chaco Plateau.  

National Technical Information Service (NTIS)

This cultural historical study of Navajo occupation of the Navajo Indian Irrigation Project (NIIP) area of northwestern New Mexico is designed to meet two objectives. The first objective is the collection, analysis, and recording of important historical a...

G. A. Bailey R. G. Bailey

1982-01-01

99

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

National Technical Information Service (NTIS)

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 ...

T. Benally

2012-01-01

100

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.

101

Aquifer-characteristics and water-chemistry data from wells on or near Navajo tribal lands in the Zuni River basin and Whitewater Arroyo drainage, west-central New Mexico  

Microsoft Academic Search

Three stratigraphic units - the alluvium, the Gallup Sandstone, and the Dakota Sandstone, have favorable water bearing characteristics and are present throughout most of the Navajo tribal lands in the Zuni River basin and Whitewater Arroyo drainage, west-central New Mexico. Reported well yields are less than 10 to 500 gal\\/min for the alluvium aquifer; 4 to 260 gal\\/min for the

1990-01-01

102

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

Microsoft Academic Search

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

Lawrence S. Jones; Edmund R. Gustason

2006-01-01

103

Uranium mining and lung cancer in Navajo men  

Microsoft Academic Search

We performed a population-based case-control study to examine the association between uranium mining and lung cancer in Navajo men, a predominantly nonsmoking population. The 32 cases included all those occurring among Navajo men between 1969 and 1982, as ascertained by the New Mexico Tumor Registry. For each case in a Navajo man, two controls with nonrespiratory cancer were selected. Of

Jonathan M. Samet; Daniel M. Kutvirt; Richard J. Waxweiler; Charles R. Key

1984-01-01

104

Dinetah: An Early History of the Navajo People.  

ERIC Educational Resources Information Center

Originally written for Navajo elementary school students, this book chronicles the history of the Navajo people from prehistory to 1868. The book presents a sympathetic history of a people who depended on their tenacity and creative adaptability to survive troubled times. Chapters examine how Navajo culture changed from that of an early hunting…

Sundberg, Lawrence D.

105

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…

Kaltenbach, Charles

106

A NAVAJO-ENGLISH THESAURUS OF GEOLOGICAL TERMS  

Microsoft Academic Search

A bilingual Navajo-English thesaurus of selected common geological and related terms is presented here for the use of geoscien- tists and geoscience educators who work on or near the Navajo Nation, or who have an interest in Navajo ethnogeology.

ALFRED BLACKHORSE; STEVEN SEMKEN; PERRY CHARLEY

107

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

108

Evaluation of lactational performance of Navajo women.  

PubMed

The effect of suboptimal maternal nutrition on lactational performance of 23 Navajo women was studied in terms of milk volume, milk composition, and infant growth. The mean milk volume produced by 10 Navajo women was 634 +/- 113 mg/24 h after approximately 1 month of lactation. The content of protein, lactose, and lipid were within normal limits. Retinol and carotene content were 32.9 +/- 15.7 and 19.7 +/- 6.3 microgram/dl, respectively. Milk folacin averaged 56.4 +/- 23.9 mg/ml. The mean contents of zinc, iron, and copper were 2.8 +/- 1.1, 0.8 +/- 0.6, and 0.3 +/- 0.2 mg/l, respectively. Despite evidence of suboptimal nutriture among these Navajo women, lactational performance was adequate in terms of infant growth, milk volume, and milk composition with the exception of vitamin A which was lower than normal. PMID:7293949

Butte, N F; Calloway, D H

1981-10-01

109

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.

110

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.

111

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

112

Paleomagnetic study of Jurassic and Cretaceous rocks from the Mixteca terrane (Mexico)  

Microsoft Academic Search

Three sites from Cretaceous limestone and Jurassic sandstone in northern Oaxaca, Mexico, were studied paleomagnetically. Thermal demagnetization isolated site-mean remanence directions which differ significantly from the recent geomagnetic field. The paleopole for the Albian–Cenomanian Morelos formation is indistinguishable from the corresponding reference pole for stable North America, indicating tectonic stability of the Mixteca terrane since the Cretaceous. Rock magnetic properties

Harald Böhnel

1999-01-01

113

Marine shelf to paralic biofacies of Upper Triassic to Lower Jurassic deposits in Spitsbergen  

Microsoft Academic Search

The Upper Triassic to Lower Jurassic Kapp Toscana Group of Spitsbergen consists of mudstones, sandstones and shales deposited in offshore marine to paralic conditions in an extensive shelf embayment. The study focuses on microfossil-based biofacies features (mainly foraminifera, but also palynomorphs) combined with sedimentary and selected geochemical data, in relation to transgressive–regressive developments. The analysed material includes field logs and

Jen? Nagy; Silvia Hess; Henning Dypvik; Tor Bjærke

2011-01-01

114

Navajo Caregivers' Perceptions of Early Intervention Services  

Microsoft Academic Search

This study investigated 52 Navajo family caregiver perceptions about early intervention services. Family-related early intervention practices were rated by caregivers to identify their perception of typical and desired practices. Data also were collected to determine the relationships between caregiver satisfaction and three variables (a) selected family-related program practices, (b) program providers, and (c) family and child characteristics. Supplemental information was

Karen L. Applequist; Donald B. Bailey

2000-01-01

115

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

NASA Astrophysics Data System (ADS)

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

Sanabria, Diego Ignacio

2001-07-01

116

Pennsylvanian to Jurassic eolian transportation systems in the western United States  

USGS Publications Warehouse

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

Peterson, F.

1988-01-01

117

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

118

Recognition and source correlation of migrated hydrocarbons in Upper Jurassic Hareelv Formation, Jameson Land, east Greenland  

SciTech Connect

Organic geochemical analysis of an interbedded shales and sandstone sequence from the Upper Jurassic Hareelv Formation, Jameson Land, East Greenland, has revealed oil shows in the sandstones, consistent with petroleum generation and migration. A comparison of the molecular characteristics of extractable material from the sandstones with those of kerogen and bitumen from the shales indicates that the most likely origin of these shows is generation within the shales with expulsion and short-range migration into the sandstones. This conclusion is based on comparisons of biological marker distributions, stable carbon isotopic compositions of extractable material and kerogen, and pyrolysate compositions of kerogen and asphaltenes. Oil from a seep in the Savoia Halvo region south of Jameson Land can be correlated to the Jurassic sandstone oil shows based on similar isotopic compositions and asphaltene pyrolysate distributions. Impregnation of both sandstones and shales throughout the sequence by products generated at higher maturities is considered unlikely, but cannot be ruled out by the existing data. 18 figs., 6 tabs.

Requejo, A.G.; Hollywood, J.; Halpern, H.I. (ARCO Oil and Gas Co., Plano, TX (USA))

1989-09-01

119

URANIUM DEPOSITS UNDER CONGLOMERATIC SANDSTONE OF THE MORRISON FORMATION, COLORADO AND UTAH  

Microsoft Academic Search

In southwestern Colorado and southeastern Utah, strata of conglomeratic ; sandstone are localized at the base of the Brushy Basin Member of the Morrison ; Formation of Jurassic age. These discrete lithologic units contain sedimentary ; structures oriented in a prevailing easterly direction. They are believed to ; cover about one-third of the underlying Salt Wash Member in southwestern Colorado

DAVID A. PHOENIX

1958-01-01

120

Effects of Boarding School on Navajo Maternal Attitudes and Behavior.  

ERIC Educational Resources Information Center

An investigation of long term effects of boarding school education was conducted among Navajo women who had attended boarding school on the reservation during the 1950's. Subjects were 23 Navajo mothers and, for 17 mothers, their preschool children; all lived in the San Francisco Bay Area. A series of open-ended interviews obtained information on…

Metcalf, Ann Rosenthal

121

"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

122

Navajo Uranium Education Programs: The Search for Environmental Justice  

ERIC Educational Resources Information Center

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

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

2004-01-01

123

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

ERIC Educational Resources Information Center

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

Two Bears, Davina R.

2006-01-01

124

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

125

The Effects of Sociocultural Factors on the Navajo Literacy Environment.  

ERIC Educational Resources Information Center

|This paper describes an ethnographic study of school and community characteristics affecting the literacy development of Navajo children, and provides an overview of sociocultural factors in the literacy environment of one Navajo community. The researcher was a principal at Pinon Public School District #4 in Pinon, Arizona, in the heart of the…

Greene, Diane C.

126

Ashkii Bizaad: Verbal Morphology Loss in One Young Speaker's Navajo  

Microsoft Academic Search

With a rich verbal morphology and an aging population of native speakers, Navajo offers a valuable opportunity to examine language attrition in detail. Few Navajo children grow up completely unexposed to their heritage language, yet the number raised as monolingual English speakers has risen sharply in the past thirty years. This thesis compares one young speaker's production of verbs with

Eric W Weisser

2008-01-01

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

Demographic Change Among the Hopi and Navajo Indians.  

National Technical Information Service (NTIS)

The growth of the Navajo and Hopi Indian populations is traced over the 100-year period from the early 1870's to the present. It is shown that the rate of growth of the Navajo population has increased more rapidly than has that of the Hopi population. It ...

S. J. Kunitz

1973-01-01

129

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

130

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

Federal Register 2010, 2011, 2012, 2013

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

2010-03-05

131

Navajo world view and culture patterns of speech: A case study in ethnorhetoric  

Microsoft Academic Search

Using ethnographic literature on the Navajo, an attempt was made to describe Navajo ideas about rhetoric. The purpose of such description was to discover the Navajo conception of rhetoric and to determine whether that conception shows significant culture patterning. The inquiry begins with an exposition of certain features of Navajo ethnophilosophy, including metaphysical, epistemological, and psychological beliefs. It is concluded

Gerry Philipsen

1972-01-01

132

Jurassic Polar Movement Relative to North America  

Microsoft Academic Search

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

ANY C. E. HELSLEY

1972-01-01

133

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

Microsoft Academic Search

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

Charles A. Braithwaite

1997-01-01

134

Jurassic-Cretaceous clastic sequences of Chukotka: sedimentation, structural style and geodynamic implications for Russian East Arctic shelf.  

NASA Astrophysics Data System (ADS)

Jurassic-Lower Cretaceous sedimentary sequence, exposed on the Chukotka continental margin is critical for understanding the timing, dynamics and sedimentary setting evolution of Chukotka-Eurasia collisional process (e.g., Sokolov et al., 2002) and so, represents one of the key regional stratigraphic units (Til'man,1973, Tibilov,1982; Miller et al., 2002, 2007). From the other hand, this research may shed the light on the widely discussing problem of the Canadian and Makarov basins opening (e.g., Miller, Verzhbitsky, in press). Jurassic-Lower Cretaceous sedimentary complexes of the Chukotka microcontinent are composed of terrigeneous deposites. Those sedimentary complexes are enriched by organic matter, and fresh clastic materials. Fragments of shales, sometimes laminated or cleaved are their indicator constituents. Sandstones are arkosic. The percentage of types of rocks fragments is different in Jurassic and Cretaceous deposits. Chemical composition of the Jurassic-Cretaceous rocks is not uniform too: Upper Jurassic sandstones form one group depleted in Na2O+K2O, Cretaceous sandstones, enriched in Na2O+K2O. Thus, our investigations indicate that Jurassic-Cretaceous sedimentary basins were related to different source provenance. We believe, that the stratigraphy and composition of Jurassic-Lower Cretaceous onshore sequences are crucial for prediction of the geological structure of East Siberian and Chukchi Sea shelf (1), understanding the evolution of Mesozoic sedimentary basins of East Arctic (2) and testifying the existing geodynamic models of Amerasian Basin opening (3). The work is supported by the Russian Foundation for Basic Research (grant 08-05-00547), program of ONZ RAS 14, and NSH-3172.2008.5.

Tuchkova, M. I.; Sokolov, S. D.; Verzhbitsky, V. E.

2009-04-01

135

Navajo coal and air quality in Shiprock, New Mexico  

USGS Publications Warehouse

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

Bunnell, Joseph E.; Garcia, Linda V.

2006-01-01

136

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

NASA Astrophysics Data System (ADS)

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

Gore, P. J. W.

137

Gas play opportunities in deeper Jurassic sequences of the Neuquen basin embayment, Argentina  

Microsoft Academic Search

We have defined new gas plays at around 4000 m depth near the giant Loma La Lata gas field. The plays, in lower Jurassic sandstones, were developed using a different approach in stratigraphic signatures as well as deformation styles. Two initial rifting stages led to the Triassic-Early Liassic volcanoclastic deposition (Precuyo s.l.) into a suite of discrete half-grabens. The late

F. Fernandez-Seveso; D. E. Figueroa; H. Rodriguez

1996-01-01

138

JURASSIC Retrieval Processing  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

139

Navajo coal and air quality in Shiprock, New Mexico  

USGS Publications Warehouse

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

Bunnell, Joseph E.; Garcia, Linda V.

2006-01-01

140

Navajo Environmental Protection Commission and the Environmental Impact Statement.  

National Technical Information Service (NTIS)

The Bulletin focuses upon the Navajo Tribal Environmental Protection Commission (NEPC) in relation to the National Environmental Policy Act's environmental impact statement (EIS) requirement. The Bulletin describes the NEPC's structure and its regulatory ...

H. J. Cortner

1976-01-01

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

Prevalence of diabetes in a Navajo Indian community.  

PubMed Central

The age- and sex-adjusted prevalence of non-insulin-dependent diabetes mellitus (NIDDM) of 494 (76 per cent) Navajo adults living in a reservation community was 10.2 per cent, approximately 60 per cent greater than the estimated prevalence (6.4 per cent) in the general US population. The screening protocol utilized likely underestimates the prevalence of NIDDM in this population. A high proportion of Navajo people were overweight when compared to the general US population.

Sugarman, J; Percy, C

1989-01-01

143

Reconstruction of the diagenesis of the fluvial-lacustrinedeltaic sandstones and its influence on the reservoir quality evolution  

Microsoft Academic Search

The reservoir quality of Jurassic and Triassic fluvial and lacustrine-deltaic sandstones of the Yanchang Oil Field in the\\u000a Ordos Basin is strongly influenced by the burial history and facies-related diagenetic events. The fluvial sandstones have\\u000a a higher average porosity (14.8%) and a higher permeability (12.7 × 10?3 ?m2) than those of the deltaic sandstones (9.8% and 5.8 ×10?3) ?m2, respectively).

Jinglan Luo; S. Morad; Xiaoli Zhang; Shike Yan; Fuli Wu; Yuhong Li; Junmin Xue

2002-01-01

144

Rethinking the role of diagnosis in Navajo religious healing.  

PubMed

Diagnosis plays a central, primary role in the therapeutic process across cultures. In this article, the authors examine the role of diagnosis in two Navajo religious healing traditions, the Traditional Navajo religion and the Native American Church (NAC), and examine a case study of a diagnostic encounter between an NAC diagnostician and a Traditional patient. The authors assert that, for Navajos, diagnosis is not merely a prescriptive rite that passively initiates the therapeutic process (as it has been seen in the Navajo literature) but can itself constitute a cure. Claims made about the similarity between Western psychotherapy and religious healing both by scholars and by the healer and patient in this case study are investigated. The authors conclude that such an analogy must be seen against the backdrop of Navajo beliefs about thought, speech, and health. Viewing diagnosis as a "talking cure" and an example of Good's concept of "narrativizing" illness (things it shares with Western psychotherapy) suggests why the analogy is appealing for Navajos themselves. PMID:11224980

Milne, D; Howard, W

2000-12-01

145

Stochastic reconstruction of sandstones  

PubMed

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

Manwart; Torquato; Hilfer

2000-07-01

146

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

147

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

Code of Federal Regulations, 2011 CFR

...permittee commence grazing on Navajo Partitioned Land? 161.307 Section 161.307 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements §...

2011-04-01

148

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

Federal Register 2010, 2011, 2012, 2013

...to the Navajo Nation, Hopi Tribe, the Gila River Indian Community, and numerous...Nation, the Gila River Indian Community, and other...the Navajo Nation and Hopi Tribe, and in Page...Fund, the Gila River Indian Community, the...

2013-07-09

149

Sand and sandstone  

SciTech Connect

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

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

1987-01-01

150

Swimming styles in Jurassic ichthyosaurs  

Microsoft Academic Search

Postcranial axial anatomy of six Jurassic ichthyosaurs is described and used to define a generalized pattern of regional anatomy with four structural units (neck, trunk, tail stock, fluke). Functional interpretation of each unit predicts a generalized swimming mode that used a laterally compressed, laterally oscillating caudal fluke as the propulsive organ. Fluke displacement was accomplished by the undulation of a

Emily A. Buchholtz

2001-01-01

151

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.

152

Reflections on the Education of Native American Children, Focusing on Navajo Children.  

ERIC Educational Resources Information Center

Offered as an introduction to some of the pertinent studies and personalities concerning the education of Native Americans, with emphasis on the education of Navajo children, this paper traces the history of Navajo education from 1868 to the present. A discussion of the shortcomings of early schools for Navajos and other Native Americans is…

Harrison, Scott

153

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Navajo Indian lands-Class II wells. 147.3400 Section...UNDERGROUND INJECTION CONTROL PROGRAMS Navajo Indian Lands § 147.3400 Navajo Indian landsâClass II wells. The UIC...

2012-07-01

154

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.

155

Tuning In to Navajo: The Role of Radio in Native Language Maintenance.  

ERIC Educational Resources Information Center

|Since 1986, KTNN Radio (tribally owned) has broadcast Navajo-language programming to the entire Navajo Nation. Its large broadcast range and position as the "Voice of the Navajo Nation" gives KTNN the "symbolic" power to affect linguistic change, as well as the unenviable position of being held to a high language standard although no such…

Peterson, Leighton C.

156

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

Microsoft Academic Search

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

Madeline Becker

2003-01-01

157

Stephannie and the Coyote (Stefanii doo Ma'ii) in Navajo and English.  

ERIC Educational Resources Information Center

|Intended as a supplementary text or a library book for Navajo children, this book is written both in English and Navajo. Color pictures illustrate each passage in the text. The pictures graphically depict the living conditions of the Navajo people. (TL)|

Crowder, Jack L.

158

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

Microsoft Academic Search

A laterally discontinuous fine-grained quartzarenite occurs at the base of the Upper Jurassic Morrison Formation in the southern Big Horn and Powder River basins and in the Wind River basin. The sandstone unit is interpreted to be an eolianite. Evidence for this includes high-angle (20-35°), medium to large-scale planar cross-beds that are tangential at the base, inversely graded foresets, and

D. D. Weed; C. F. Vondra

1987-01-01

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

Neuropathy in Navajo children: clinical and epidemiologic features.  

PubMed

We describe a rare and apparently unique neuropathic syndrome among Navajo children living on the Navajo Reservation. Clinical features include sensorimotor neuropathy, corneal ulcerations, acral mutilation, poor weight gain, short stature, sexual infantilism, serious systemic infections, and liver derangement including Reye's syndrome-like episodes. Progressive CNS white matter lesions were diagnosed through magnetic resonance imaging. We identified 20 definite and 4 probable cases occurring between 1959 and 1986. Mean age at the time of 1st recognized symptom was 13 months (range, 1 month to 4 years 6 months). Ten individuals have died; 6 of the deaths occurred before 5 years of age. The incidence of this syndrome on the western Navajo reservation is 5 times higher than that on the eastern reservation (38 compared with 7 cases per 100,000 births). Although the etiology is unknown, this syndrome is consistent with an inborn error of metabolism, inherited in an autosomal recessive manner. PMID:2300261

Singleton, R; Helgerson, S D; Snyder, R D; O'Conner, P J; Nelson, S; Johnsen, S D; Allanson, J E

1990-02-01

161

Exploration in Jurassic of North Mafla, eastern Gulf of Mexico  

SciTech Connect

Exploration in North Mafla focuses on general categories of prospects, potential reservoirs and their associated facies, and seismic modeling of available well control. Jurassic prospects in North Mafla can be classified into four general categories: (1) basement-related structures: (2) closures associated with the Pensacola-Destin peripheral fault trend, (3) salt anticlines, and (4) prospects associated with the interregional structural highs. Each of these categories can be related to documented, predictable, and repeated patterns of hydrocarbon accumulations in east Texas, north Louisiana, Mississippian, Alabama, and Florida. The primary objectives in North Mafla are the Jurassic Smackover carbonates and Norphlet sands at depths ranging rom 15,000 to 25,000 ft. Major gas accumulations in the Norphlet around Mobile Bay are separated from thicker sequences of Norphlet sands in the De Soto Salt basin by the offshore extension of the Pensacola arch. Seismic geometries suggest that Smackover high-energy carbonates may have been deposited on the crest of some of these thick Norphlet sands. Seismic modeling indicates that a high-amplitude, laterally continuous event associated with a Norphlet-Louann Salt contact is dependent on the presence of Pine Hill anhydrite member of the Louann Salt. In addition, seismic reflection geometries indicate that the Norphlet sandstone thickens from +/- 300 ft on the eastern flank of the Destin Dome to nearly 1000 ft nearby. Although drilling in the lightly explored Norch Mafla area has yielded few substantive results to date, the elements necessary for significant hydrocarbon accumulations are known to exist.

Kemmer, D.A.

1987-05-01

162

Paleotectonic controls on deposition of upper Upper Jurassic La Casita Formation, east-central Chihuahua, Mexico  

SciTech Connect

Surface mapping of the basal Mesozoic La Casita Formation (upper Upper Jurassic) in east-central Chihuahua, Mexico, indicates initial Mesozoic sedimentation occurred in a segmented, interconnected subbasin of the Chihuahua trough. La Casite Formation (1200 m thick) is a tectonostratigraphic unit resting with angular unconformity on the Lower Permian Plomosas Formation. It consists primarily of siliciclastic material with sporadic interbedded limestones. The dominant lithofacies, approximately 1000 m thick, consists of turbiditic sandstone units (10-20 m) alternating with thicker, monotonous shale sequences. In the mapped area (approximately 30 km/sup 2/), flute cast measurements indicate flows from both the northeast (N20/degree/E) and southwest (S58/degree/W). Turbiditic sandstone units appear to pinch out and/or interfinger as they extend from the north and south into the central portion of the area. The initial opening of the Chihuahua trough is often associated with Late Jurassic block faulting, related to development of the ancestral Gulf of Mexico. Synrift depositional sequences of a similar age have been described in southern Coahuila, northern Zacatecas, and western Chiapas, Mexico. The subbasin (graben ) examined here may be ascribed a paleoposition near the western edge of the early Chihuahua trough. The western boundary of the early trough may have comprised a series of these subbasins, forming a cuspate or serrated coastline. Late Jurassic ammonites recovered from this and other localities along the length of the Chihuahua trough suggest that the subbasins were interconnected by means of an eastern continuous seaway.

Roberts, D.C.

1989-03-01

163

Anisotropy of sandstone permeability  

Microsoft Academic Search

Small-scale probe permeability measurements on differently oriented faces of highly compacted and quartz-cemented Viking Formation sandstones yield detailed permeability distributions that appear to be diagnostic of the grain- and lamina-scale fabric of the samples. Permeability anisotropy of a single 'structureless'-appearing sample is low, reflected by a kV \\/ kH-ratio of 0.7; corresponding k-distributions are homogeneous. Permeability anisotropy of a strongly

Rudi Meyer

164

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

SciTech Connect

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

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

1995-12-31

165

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

166

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

167

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

168

Decolonizing the Navajo Nation: The Lessons of the Naabaahii  

ERIC Educational Resources Information Center

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

Lee, Lloyd L.

2011-01-01

169

Of Saints and Lamanites: An Analysis of Navajo Mormonism.  

ERIC Educational Resources Information Center

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

Pavlik, Steve

1992-01-01

170

A Navajo High School and the Truth of Trees.  

ERIC Educational Resources Information Center

|A non-Indian teacher at a Navajo Reservation high school relates his experiences using American Indian literature to convey to students some of the unspoken truths of American Indian history; and muses on the nature of truth and the etymological origins of the word "truth" in the word "tree." (SV)|

Dunsmore, Roger

1991-01-01

171

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

ERIC Educational Resources Information Center

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

Spolsky, Bernard

2002-01-01

172

Using Cultural Knowledge in Health Promotion: Breastfeeding among the Navajo  

Microsoft Academic Search

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

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

1997-01-01

173

Eyewitness Reporting by Navajo and Mainstream-Culture Children.  

ERIC Educational Resources Information Center

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

Lindstedt, D. Elise

2000-01-01

174

Culturally Related Anxiety and Ethnic Identity in Navajo College Students  

Microsoft Academic Search

The Cultural Involvement and Detachment Anxiety Questionnaire (D. W. McNeil, C. A. Porter, M. J. Zvolensky, & J. M. Chaney, 1998) and the Multigroup Ethnic Identity Measure (J. S. Phinney, 1992) were administered to 160 Navajo college students to explore the relation between ethnic identity and culturally related anxiety, compare level of ethnic identity in reference to standardized samples, and

Daniel W. McNeil; Marvin Kee; Michael J. Zvolensky

1999-01-01

175

The changing epidemiology of diabetes mellitus among Navajo Indians.  

PubMed Central

Although early descriptions of diabetes mellitus among Navajo Indians characterized the disease as an infrequent and "benign chemical abnormality," the prevalence of diabetes and its complications among Navajos appears to have increased substantially in this century. We reviewed recent Indian Health Service inpatient and ambulatory care data and compared these data with previous reports. Of the estimated Navajo population aged 45 years or older, 4,331 (16.9%) had an ambulatory care visit for diabetes between October 1, 1986, and September 30, 1987. Diabetes was coded for 1,041 (7.0%) of hospital admissions of persons aged 20 and older. Of 377 lower-extremity amputations done from 1978 to 1987, diabetes was involved in 245 (66%). The 1986 age-adjusted mortality rate from diabetes was 30.3 per 100,000, approximately twice that for the general US population. The explanation for the increased prevalence of diabetes mellitus among Navajos probably relates to an increasing prevalence of obesity.

Sugarman, J. R.; Hickey, M.; Hall, T.; Gohdes, D.

1990-01-01

176

Acculturation and changes in health among Navajo boarding school students.  

PubMed

This paper describes the relationship between cultural background and illness experience among Navajo students during their first year at a reservation boarding school. Sixty Navajo children were enrolled in a 9-month, prospective study in which three descriptors of change in health status were assessed: (a) number of dormitory aide contacts initiated by the child for an illness complaint; (b) number of clinic visits for an illness judged by the aide to require medical attention; and (c) number of psychosocial problems referred to the clinic or to the boarding school administration. Two measures of cultural background were developed to estimate the location of each child along a continuum of acculturation, ranging from a traditional Navajo cultural orientation to full assimilation into modern Anglo-American society. First, the home communities for all children in the study population were ranked by eleven Navajo informants on an equal-interval scale reflecting community differences in cultural identity. Second, a questionnaire assessing acculturative dimensions of family life style was administered to each child by a Navajo assistant. In addition, each student was assigned a score for cultural incongruity, defined as the degree of absolute difference between community and family measures of cultural background. The reliability and validity of each index of acculturation were confirmed using a variety of psychometric approaches. Controlling for the confounding effects of age, sex and family size, a significant positive association was found between the number of clinic visits and the degree of cultural incongruity. Boarding school students from families and communities which conflicted in cultural orientation experienced higher rates of clinic visits for illnesses requiring medical attention. This result is discussed in the context of current understandings of the epidemiological consequences of cultural change. PMID:6844954

Boyce, W T; Boyce, J C

1983-01-01

177

Characterising the structure and petrophysical properties of deformation band fault cores in reservoir sandstone  

NASA Astrophysics Data System (ADS)

Deformation band faults in porous sandstone typically have a "core" of intense deformation associated with the localisation of strain onto discrete slip surfaces. In outcrop, the core is recognisable by its glassy appearance and its increased resistance to erosion with respect to the host rock. Samples of fault core have been collected from the San Rafael Swell, Utah, USA (Navajo Sandstone) and the Cheshire Basin, England (Sherwood Sandstone). Outcrop mapping in both localities reveals that the fault core thickness varies from < 3 cm to 30 cm along strike. Thickness variability does not correlate with displacement. The fault core is composed of closely spaced deformation bands and the host rock between these deformation bands is highly crushed. The mean grain size in the fault core is lower than in single deformation bands and there is a greater spread of particle sizes. Quartz grains in the fault core tend to be aligned. Fault core porosity (1-5%) is decreased with respect to the host sandstone (17-22%) and individual deformation bands (7-8%). However, microstructural observations suggest that fluids have moved through these structures during deformation. Cement phases are preferentially located along deformation band boundaries. Clay rims, which are common in the host rock, are absent in the fault core. Additionally preliminary fluid inclusion data show elevated temperatures in healed fault core microfractures. It is essential to characterise the architecture, composition and porosity/permeability of fault core to accurately predict fluid flow parallel and perpendicular to deformation band fault zones.

Bright, A. M.; Shipton, Z. K.

2003-04-01

178

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

Microsoft Academic Search

Phreatomagmatic deposits at Narbona Pass, a mid-Tertiary maar in the Navajo volcanic field (NVF), New Mexico (USA), were characterized in order to reconstruct the evolution and dynamic conditions of the eruption. Our findings shed light on the temporal evolution of the eruption, dominant depositional mechanisms, influence of liquid water on deposit characteristics, geometry and evolution of the vent, efficiency of

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

2009-01-01

179

Facies architecture of tidal shelf sandstone ridge: Tocito sandstone  

SciTech Connect

The lithofacies architecture of a single Tocito Sandstone Lentil has been documented in outcrops near the Hogback oil field west of Farmington with a very detailed outcrop study. This isolated Tocito sand body is composed of a three-tiered hierarchy of linear ridge elements. The large-scale Tocito Sandstone Lentil is approximately 5 km wide, 30 km long, and up to 16 m thick. The lentil is composed of at least three smaller scale ridges, which are up to 1 km wide, of unknown length, and up to 16 m thick. The small-scale ridges are arranged such that each new ridge accreted on the landward margin of the previous ridge. These smaller scale ridges consist of an ordered arrangement of four basic lithofacies: (1) burrowed, muddy sandstone, (2) interbedded clean and muddy sandstone, (3) cross-bedded sandstone, and (4) ripple-bedded sandstone. burrowed, muddy sandstone is found at the base of the small-scale ridges, is laterally extensive, and is interpreted as forming downcurrent from the most active portion of the ridge. The cross-bedded sandstone forms ribbon-shaped sand bodies elongate in the direction of ridge elongation. Typically the sand ribbons are 100-300 m wide, 2-4 m thick, and up to 1 km long. Usually two or more combine to form a small-scale ridge. The interbedded sandstone is found above the cross-bedded lithofacies as well as between the sand ribbons. The ripple-bedded facies is always found at the top of the section and represents the waning stage of ridge growth. The resulting architecture is one of coalesced sand ribbons combining to form the small-scale ridges, and subsequently small-scale ridges accreting landward to form a composite Tocito Sandstone Lentil.

Riley, G.W.; Nummedal, D. (Louisiana State Univ., Baton Rouge (USA))

1989-09-01

180

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

ERIC Educational Resources Information Center

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

Webster, Anthony K.

2010-01-01

181

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

SciTech Connect

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

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

1988-09-01

182

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

USGS Publications Warehouse

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

Eychaner, James H.

1981-01-01

183

Jesus, peyote, and the holy people: alcohol abuse and the ethos of power in Navajo healing.  

PubMed

Of the three religious healing traditions that coexist within the contemporary Navajo health care system, the Native American Church (NAC) and Pentecostal Christianity are more actively involved in the treatment of alcohol and substance abuse than is Traditional Navajo healing. This article examines these two more recent healing traditions as religious responses to the contemporary Navajo crisis of alcohol and substance abuse as well as to socioeconomic changes. These traditions offer new kinds of power, social networks, and personal meaning that facilitate a transformation of self, a revitalized sense of community, and a new vision of the possibilities of the future for Navajo people who suffer. Examining the ethos of power that underlies Navajo healing can complement the theoretical emphasis on harmony and beauty in anthropological research on Navajo culture and religion. PMID:11224979

Garrity, J F

2000-12-01

184

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.

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

2008-01-01

185

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

USGS Publications Warehouse

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

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

1997-01-01

186

Promotion of a Healthy Weight Among Navajo Nation Women.infant and Children Families  

Microsoft Academic Search

LEARNING OUTCOME: To identify three activities to use with paraprofessionals in promoting a healthy weight for children enrolled in the Navajo Nation Women, Infant and Children (WIC)programHigh weight-for-height (>95th percentile) has increased over the last twelve years in the Navajo Nation's infants and children. Out of 28,772 records examined by the 1994 CDC Pediatric Nutrition Surveillance System for the Navajo

V. Browning; D. McGuire

1996-01-01

187

Risk factors for conduct disorder among Navajo Indian men and women  

Microsoft Academic Search

Objectives: To describe the risk factors for conduct disorder before age 15 among Navajo Indians. Methods. The study was based on a\\u000a survey of a stratified random sample of adult Navajo Indians between the ages of 21 and 65 living on and adjacent to two different\\u000a areas of the Navajo Reservation. There were 531 male and 203 female respondents. The

S. J. Kunitz; K. R. Gabriel; J. E. Levy; E. Henderson; K. Lampert; J. McCloskey; G. Quintero; S. Russell; A. Vince

1999-01-01

188

Sandstones of unexpectedly high diffusibility.  

PubMed

Measurements have been made of diffusion coefficients (D(i)=-mass flux/concentration gradient) using a double reservoir, steady-state method with two tracers, CaBr(2) and amino-G-acid, on intact samples of Triassic red-bed sandstone from northwest England. Diffusibility (D'=D(i)/diffusion coefficient in water) averages 0.124, ranging between 0.075 and 0.215 (porosity 0.1 to 0.24), very similar for the two tracers. Implied tortuosities (actual path length/straight line length) average 1.21 (range 1.06 to 1.47), with constrictivities close to 1. In comparison with limited red-bed sandstone data from elsewhere, these D' values are up to 4 times greater, and tortuosity correspondingly lower. Re-interpretation of formation factor data from previous studies on shallow sandstone samples also from northwest England confirms that diffusibility is significantly higher in these sandstones than others from similar palaeoenvironment/stratigraphic units. The lower tortuosities appear to result from the relatively high permeability, open fabric of the rock, properties likely to be present in shallow sandstone systems used for water supply. It is concluded that diffusion rates may, in some shallow freshwater-containing continental sandstone systems, be significantly greater than is implied by estimates of sandstone diffusibility current in the literature. PMID:21146250

Bashar, Khairul; Tellam, John H

2010-11-23

189

The role of provenance in illitization of deeply buried reservoir sandstones from Haltenbanken and north Viking Graben, offshore Norway  

Microsoft Academic Search

An extensive mineralogical and geochemical database has been compiled to evaluate the relationship between diagenesis and provenance of the Lower\\/Middle Jurassic sandstones from the Haltenbanken (Mid-Norway) and north Viking Graben. The data from the Haltenbanken area, from burial depths between 2.1 and 4.5 km relative to seafloor (RSF), show a reduction in K-feldspar and kaolin, and a sharp increase in

Fawad A Chuhan; Knut Bjørlykke; Caroline Lowrey

2000-01-01

190

Stress-dependent permeability evolution in sandstones with anisotropic physical properties  

NASA Astrophysics Data System (ADS)

Fluid flow in reservoir rocks is strongly dependent on stress path and rock microstructure which may present a significant anisotropy. We present recent experimental data on the evolution of permeability with applied stress for three sandstones tested under triaxial conditions in the low confining pressure range (<10 MPa). Samples with diameter 40 mm and length 80 mm were cored in three orthogonal directions in blocks retrieved from quarries. One coring direction was perpendicular to the bedding plane whereas the other directions were arbitrarily chosen within the bedding plane. The selected rocks are the Bentheim sandstone (BNT), a quartz-rich cretaceous sandstone from Germany with 24% porosity, and two different varieties of a same jurassic formation in Northern Spain, the La Marina sandstone. The Yellow La Marina sandstone (YLM) with porosity 28% has a low cohesion and is the weathered form of the well-consolidated Grey La Marina sandstone (GLM) with porosity 17%. When loaded up to the failure stress, the more porous sandstones (BNT, YLM) exhibited a monotonic decrease of permeability even when the rock was dilating at deviatoric stresses close to the failure stress. On the other hand the permeability of the less porous sandstone (GLM) increased during the dilating phase. These results are in agreement with previous studies. In addition we observed that all three sandstones are anisotropic with respect to several physical properties including permeability. We systematically found a lower permeability in the direction perpendicular to the bedding plane, but the ratio of "vertical" to "horizontal" permeability varies from one sandstone to the other. The permeability anisotropy is compared to the anisotropy of electrical conductivity, acoustic velocity, capillary imbibition and elastic moduli: in general good correlations are found for all the properties. For the Bentheim sandstone, a microstructural study on thin sections revealed that the rock anisotropy is due to the anisotropy of intergranular pores which statistically are found to be elongated within the bedding plane. This result is in agreement with the prediction of Kachanov's model for the anisotropy of acoustic velocity in Bentheim sandstone.

Metz, V.; David, C.; Louis, L.; Rodriguez Rey, A.; Ruiz de Argandona, V. G.

2003-04-01

191

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

192

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

193

The HLA loci of th Hopi and Navajo.  

PubMed

The purpose of this paper is to present the genetic distribution at the HLA-A, B, C, and DR loci in the Hopi and the Navajo. A sample of 100 out-patients from each tribe was selected at the Public Health Service Indian Hospital in Keam's Canyon, Arizona, and was typed for the antigens at the four loci. The distributions of the alleles and the haplotypes are similar in each tribe. A distance measure, f, confirms the genetic similarity of the two populations. It is concluded that the great cultural diversity of the Hopi and the Navajo is the result of a cultural evolution and diversification that has greatly outstripped the genetic evolution at the major histocompatibility loci over the past 20,000 years. PMID:7325222

Williams, R C; Morse, H G; Bonnell, M D; Rate, R G; Kuberski, T T

1981-11-01

194

OBESITY AND PULMONARY FUNCTION IN NAVAJO AND HOPI CHILDREN  

Microsoft Academic Search

Results: Approximately 26% of Navajo and Hopi children were defined as overweight (26.0% of boys and 25.6% of girls) and an additional 16% (14.6% of boys and 17.7% of girls) were defined as obese. In general, the patterns showed an increase in pulmonary function between normal weight and over- weight children and a decrease in pulmonary function of obese children.

Joey C. Eisenmann; David A. Arnall; Verdell Kanuho; Christina Interpretter; J. Richard Coast

2007-01-01

195

Navajo birth outcomes in the Shiprock uranium mining area  

Microsoft Academic Search

The role of environmental radiation in the etiology of birth defects, stillbirths, and other adverse outcomes of pregnancy was evaluated for 13,329 Navajos born at the Public Health Service\\/Indian Health Service Hospital in the Shiprock, NM, uranium mining area (1964-1981). More than 320 kinds of defective congenital conditions were abstracted from hospital records. Using a nested case-control design, families of

L. M. Shields; W. H. Wiese; B. J. Skipper; B. Charley; L. Benally

1992-01-01

196

Log interpretation of shaly sandstones  

SciTech Connect

The determination of water saturation from electrical resistivity measurements to evaluate the potential of reservoirs is a fundamental tool of the oil industry. Shaly sandstones are difficult to evaluate because clays are conductive and they lower the resistivity of the rock. A review of shaly-sandstone research concerning ''volume-of-shale'' equations reveals three theoretical categories: (1) laminated clay equations, (2) dispersed clay equations, and (3) equations that assume that the effect of the clays on the conductivity measurement is directly related to water saturation. A new model for predicting the relative amounts of laminated and dispersed shales and accounting for their effects according to their abundance can be used for any sandstone, clean or shaly. Equations representing each of the three theoretical categories and the new equation were tested on cored Wilcox sandstones from two wells. Cores were analyzed to determine the volume and distribution of clays and to correlate porosity with the well logs.

Baker, J.F.

1988-01-01

197

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

198

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

Microsoft Academic Search

Phreatomagmatic deposits at Narbona Pass, a mid-Tertiary maar in the Navajo volcanic field (NVF), New Mexico (USA), were characterized\\u000a in order to reconstruct the evolution and dynamic conditions of the eruption. Our findings shed light on the temporal evolution\\u000a of the eruption, dominant depositional mechanisms, influence of liquid water on deposit characteristics, geometry and evolution\\u000a of the vent, efficiency of

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

2009-01-01

199

Jurassic Rhynchonellids: Internal Structures and Taxonomic Revisions.  

National Technical Information Service (NTIS)

Jurassic brachiopods of the order Rhynchonellida are classified according to modern concepts and techniques, with special attention to internal structures. They are grouped into 6 families and 16 subfamilies of which three are new: the Acanthorhynchiinae,...

X. Y. Shi R. E. Grant

1993-01-01

200

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

ERIC Educational Resources Information Center

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

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

201

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

202

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

ERIC Educational Resources Information Center

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

Dalla, Rochelle L.

203

Spiritual Knowledge for a Secular Society: Traditional Navajo Spirituality Offers Lessons for the Nation.  

ERIC Educational Resources Information Center

|Explains four forms of spiritual knowledge in Navajo tradition. The first emphasizes character development; second, self-reliance; third, emotional ties and relationships with family, community, nation, and the natural environment; and fourth, reverence and respect for nature. The goal of Navajo (Dine) philosophy is balance, holism, and harmony.…

Benally, Herbert John

1992-01-01

204

The WISC-R and Evidence of Item Bias for Native-American Navajos.  

ERIC Educational Resources Information Center

|Investigated cultural bias in 79 items of three verbal tests of the Wechsler Intelligence Scale for Children-Revised (WISC-R). Administered three subtests to 40 Anglo- and 40 Native-American Navajo subjects. Results indicated 15 of 79 items (information, similarities, and vocabulary subtests) were biased against the Navajo sample. (Author)|

Mishra, Shitala P.

1982-01-01

205

A CASE-CONTROL STUDY OF RISK FACTORS FORHAEMOPHILUS INFLUENZAE TYPE B DISEASE IN NAVAJO CHILDREN  

Microsoft Academic Search

To understand the potential risk factors and protective factors for invasive Haemophilus influenzae type b (Hib) disease, we conducted a case-control study among Navajo children less than two years of age resident on the Navajo Nation. We analyzed household interview data for 60 cases that occurred between August 1988 and February 1991, and for 116 controls matched by age, gender,

MARK C. WOLFF; LAWRENCE H. MOULTON; WENDY NEWCOMER; RAYMOND REID; MATHURAM SANTOSHAM

1999-01-01

206

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

207

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

208

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.

209

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

Federal Register 2010, 2011, 2012, 2013

On February 5, 2013, EPA proposed a Best Available Retrofit Technology (BART) determination for oxides of nitrogen (NOX) for the Navajo Generating Station (NGS), located on the Navajo Nation, and provided a three-month period to accept public comments that was scheduled to close on May 6, 2013. At the request of interested stakeholders, EPA extended the comment period on two occasions,......

2013-09-25

210

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

211

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

212

Spiritual Knowledge for a Secular Society: Traditional Navajo Spirituality Offers Lessons for the Nation.  

ERIC Educational Resources Information Center

Explains four forms of spiritual knowledge in Navajo tradition. The first emphasizes character development; second, self-reliance; third, emotional ties and relationships with family, community, nation, and the natural environment; and fourth, reverence and respect for nature. The goal of Navajo (Dine) philosophy is balance, holism, and harmony.…

Benally, Herbert John

1992-01-01

213

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

Federal Register 2010, 2011, 2012, 2013

...CFR 161, implementing the Navajo-Hopi Settlement Act of 1974, 24 U.S...640d-6402-31, as amended by the Navajo-Hopi Indian Relocation Amendments Acts of 1980...S. 758 (1963) (Healing II), Hopi Tribe v. Watt, 530 F. Supp....

2010-01-27

214

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

Federal Register 2010, 2011, 2012, 2013

...part 161, implementing the Navajo- Hopi Settlement Act of 1974, 24 U.S...640d-6402-31, as amended by the Navajo-Hopi Indian Relocation Amendments Acts of 1980...S. 758 (1963) (Healing II), Hopi Tribe v. Watt, 530 F. Supp....

2010-03-31

215

Petrology, geochemistry, and Na metasomatism of Triassic-Jurassic non-marine clastic sediments in the Newark, Hartford, and Deerfield rift basins, northeastern USA  

Microsoft Academic Search

Many sandstones and associated siltstones and shales of the Triassic-Jurassic Newark Supergroup in the Newark, Hartford, and Deerfield rift basins are immature feldspathic alluvial and lacustrine closed-basin deposits. They were derived from felsic igneous and metamorphic continental blocks on the flanks of their depositional basins. The provenance was dominantly calc-alkaline basement rocks similar to the Sierra Nevada of California. The

Peter C. van de Kamp; Bernard E. Leake

1996-01-01

216

Regressive and transgressive cycles in a rift-basin: Depositional model and sedimentary partitioning of the Middle Jurassic Hugin Formation, Southern Viking Graben, North Sea  

Microsoft Academic Search

The Jurassic Hugin Formation consists of shallow-marine sandstones that belong to a significant hydrocarbon reservoir in the Sleipner area in the Norwegian North Sea. The formation encompasses coarsening-upward units of mouth bar and shoreface facies, interpreted to record delta outbuilding during regression; and fining-upward units with tidal channel, dune, and tidal flat facies interpreted as part of an estuary environment

Atle Folkestad; Nicholas Satur

2008-01-01

217

Conglomeratic fan deltas and submarine fans of the Jurassic Laberge Group, Whitehorse Trough, Yukon Territory, Canada: fore-arc sedimentation and unroofing of a volcanic island arc complex  

Microsoft Academic Search

The Lower and Middle Jurassic Laberge Group consists of conglomerates, sandstone turbidites and shales that were deposited within a deep-water fore-arc trough. The conglomerate of the Laberge Group accounts for most of the preserved basin-fill within the Whitehorse Trough, and was derived from exhumed plutons, comprising multiple intrusives and extrusives of varying composition, that formed an island arc terrane in

John R. Dickie; Frances J. Hein

1995-01-01

218

The whole universe is my cathedral: a contemporary Navajo spiritual synthesis.  

PubMed

This article discusses the three major spiritual healing ways used by Navajo Indians today: Traditional healing practices that have been used for generations and still have a dynamic existence relevant to everyday Navajo life; Christian healing traditions, ranging from Catholic Charismatic to Protestant Pentecostal; and practices of the Native American Church (NAC). The complex relationship among these healing traditions on the Navajo reservation is examined through a case study of a Navajo woman whose personal spirituality includes all three. Faced with serious medical problems, this devout Catholic turned to Navajo Traditional and Native American Church spiritual diagnosis and treatment. This analysis is the occasion for a reflection on the contemporary relevance of the kind of spiritual synthesis characterized in this woman's experience. PMID:11224978

Begay, D H; Maryboy, N C

2000-12-01

219

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.

220

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.

221

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

222

Cardiovascular disease in Navajo Indians with type 2 diabetes.  

PubMed Central

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

Hoy, W; Light, A; Megill, D

1995-01-01

223

A study of dog bites on the Navajo reservation.  

PubMed Central

Reservation-wide dog-bite statistics indicate a bite rate on the Navajo Reservation that is comparable to that of a large city. Detailed analysis of 772 bite reports was made to determine the characteristics of biters and their victims. This included an assessment of the behavioral antecedents leading up to the bite incident; 98.4 percent of all cases for which a possible cause could be ascertained were provoked in some way. Both dog control and public education measures need to be taken to reduce the frequency of dog bites.

Daniels, T J

1986-01-01

224

Florida: A Jurassic transform plate boundary  

NASA Astrophysics Data System (ADS)

Magnetic, gravity, seismic, and deep drill hole data integrated with plate tectonic reconstructions substantiate the existence of a transform plate boundary across southern Florida during the Jurassic. On the basis of this integrated suite of data the pre-Cretaceous Florida-Bahamas region can be divided into the pre-Jurassic North American plate, Jurassic marginal rift basins, and a broad Jurassic transform zone including stranded blocks of pre-Mesozoic continental crust. Major tectonic units include the Suwannee basin in northern Florida containing Paleozoic sedimentary rocks, a central Florida basement complex of Paleozoic age crystalline rock, the west Florida platform composed of stranded blocks of continental crust, the south Georgia rift containing Triassic sedimentary rocks which overlie block-faulted Suwannee basin sedimentary rocks, the Late Triassic-Jurassic age Apalachicola rift basin, and the Jurassic age south Florida, Bahamas, and Blake Plateau marginal rift basins. The major tectonic units are bounded by basement hinge zones and fracture zones (FZ). The basement hinge zone represents the block-faulted edge of the North American plate, separating Paleozoic and older crustal rocks from Jurassic rifted crust beneath the marginal basins. Fracture zones separate Mesozoic marginal sedimentary basins and include the Blake Spur FZ, Jacksonville FZ, Bahamas FZ, and Cuba FZ, bounding the Blake Plateau, Bahamas, south Florida, and southeastern Gulf of Mexico basins. The Bahamas FZ is the most important of all these features because its northwest extension coincides with the Gulf basin marginal fault zone, forming the southern edge of the North American plate during the Jurassic. The limited space between the North American and the South American/African plates requires that the Jurassic transform zone, connecting the Central Atlantic and the Gulf of Mexico spreading systems, was located between the Bahamas and Cuba FZ's in the region of southern Florida. Our plate reconstructions combined with chronostratigraphic and lithostratigraphic information for the Gulf of Mexico, southern Florida, and the Bahamas indicate that the gulf was sealed off from the Atlantic waters until Callovian time by an elevated Florida-Bahamas region. Restricted influx of waters started in Callovian as a plate reorganization, and increased plate separation between North America and South America/Africa produced waterways into the Gulf of Mexico from the Pacific and possibly from the Atlantic.

Klitgord, Kim D.; Popenoe, Peter; Schouten, Hans

1984-09-01

225

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

SciTech Connect

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

Dean, J.S.

1986-05-01

226

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

SciTech Connect

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

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

1989-05-01

227

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

228

Navajo Coal Combustion and Respiratory Health Near Shiprock, New Mexico  

PubMed Central

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

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

2010-01-01

229

Risk factors for suicide attempts among Navajo adolescents.  

PubMed Central

BACKGROUND: Rates of adolescent suicide in the United States are highest among Native Americans but little is known about risk factors for suicide attempts in this population. METHODS: To identify risk factors for self-reported suicide attempts by Navajo adolescents, we analyzed the 1988 Indian Health Service Adolescent Health Survey that was administered to 7,254 students in grades 6 through 12 on the Navajo reservation. The responses of students reporting a past suicide attempt were compared to others. RESULTS: Nearly 15 percent (N = 971) reported a previous suicide attempt; over half of those admitted to more than one attempt. Controlling for age, a logistic regression model revealed the following associations with suicide attempts: a history of mental health problems (OR = 3.2); alienation from family and community (OR = 3.2); having a friend who attempted suicide (OR = 2.8); weekly consumption of hard liquor (OR = 2.7); a family history of a suicide or attempt (OR = 2.3); poor self-perception of health (OR = 2.2); a history of physical abuse (OR = 1.9); female gender (OR = 1.7); and sexual abuse (OR = 1.5). CONCLUSIONS: Efforts to prevent adolescent suicide attempts in this population should target individuals with those risk factors of the highest risk and prevalence of exposure.

Grossman, D C; Milligan, B C; Deyo, R A

1991-01-01

230

Porosity prediction in sandstones using erosional unconformities  

Microsoft Academic Search

Erosional unconformities of subaerial origin are created by tectonic uplifts and eustatic sea level fall. Most erosional unconformities developed on sandstones are planes of increased porosity because uplifted sandstones are exposed to undersaturated COâ-charged meteoric waters that result in dissolution of unstable framework grains and cements. The chemical weathering of sandstones is intensified in humid regions by the heavy rainfall,

Shanmugam

1989-01-01

231

Porosity prediction in sandstones using erosional unconformities  

Microsoft Academic Search

Erosional unconformities of subaerial origin are created by tectonic uplifts and eustatic sea level fall. Most erosional unconformities developed on sandstones are planes of increased porosity because uplifted sandstones are exposed to undersaturated COâ-charged meteoric waters that result in dissolution of unstable framework grains and cements. The chemical weathering of sandstones is intensified in humid regions by heavy rainfall, lush

Shanmugam

1988-01-01

232

Black Weathering of Bentheim and Obernkirchen Sandstone  

Microsoft Academic Search

Black weathering of sandstone in monuments is widespread. Some objects owe their name to it, like the Porta Nigra in Trier (Germany). Other than the black gypsum crusts common on limestone, the black weathering layer on sandstone is rather thin and well adherent. Formation of such layers on Bentheim and Obernkirchen sandstone, both widely used in the Netherlands, has been

T. G. Nijland; C. W. Dubelaar; R. P. J. Van Hees; T. J. M. Linden

2003-01-01

233

Late Jurassic salamandroid from western Liaoning, China.  

PubMed

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

Gao, Ke-Qin; Shubin, Neil H

2012-03-12

234

Late Jurassic salamandroid from western Liaoning, China  

PubMed Central

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

Gao, Ke-Qin; Shubin, Neil H.

2012-01-01

235

Fundamentally Different Failure Mechanisms Around Boreholes in two High Porosity Sandstones  

NASA Astrophysics Data System (ADS)

We compare the shape and mechanism of failure around vertical boreholes drilled in blocks of two high-porosity sandstones subjected to unequal far-field principal stresses. Tablerock sandstone has a porosity of 28%, and is composed of 55% quartz and 37% weaker feldspar grains. Grain cementation is substantial through microcrystalline quartz. Critical far-field stresses induce failure around boreholes in the form of V-shaped (dog-eared) breakouts, the result of dilatant intra-and trans-granular microcracking subparallel to both the maximum horizontal far-field stress and to the borehole wall. No localized deformation ahead of the breakout tip is observed. On the other hand, boreholes in Mansfield sandstone, which has similar porosity (26%), but contains mainly quartz grains (90%) held together primarily by spot-sutured contacts, fail by developing fracture-like breakouts. These are long and very narrow (several grain diameters) tabular failure zones perpendicular to the maximum stress. Evidence provided mainly by SEM observations suggests a failure process initiated by localized grain-bond loosening along the least horizontal far-field stress springline, the packing of these grains into a lower porosity compaction band resembling those discovered in Navajo and Aztec sandstones, and the emptying of the loosened grains by the circulating drilling fluid starting from the borehole wall. Although the immediate several grain layers at the breakout tip often contain some cracked or even crushed grains, the failure mechanism enabled by the formation of the compaction band is largely non-dilatant, a major departure from the dilatant mechanism considered typical for rocks. The experimental results suggest that unlike our previous assertion, the type of grain bonding and mineral composition, and not the porosity, are major factors in the formation of compaction bands and the ensuing fracture-like breakouts.

Haimson, B.; Lee, H.

2003-12-01

236

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

237

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

238

The conservation of A Jurassic Ichthyosaur  

Microsoft Academic Search

Examination of a Jurassic ichthyosaur, prepared for wall display in the nineteenth century and currently in storage in the National Museums and Galleries of Wales (NMGW), revealed extensive deterioration of the plaster mount caused by movement of the wooden frame. During the project to create a new stable support, it was found that the specimen had undergone significant reconstruction when

Caroline Buttler; Alison Stooshnov

2002-01-01

239

Tectonism and eustasy in the Jurassic  

Microsoft Academic Search

Intensive orogenic activity and vulcanicity during the Jurassic was largely confined to the circum-Pacific geosynclinal belt and the Caucasus-Crimea region of the Tethyan Belt. Notable vulcanicity also occurred within the stable shield regions of Africa, Australia and Antarctica. There was an increase of tectonic activity throughout the course of the period, reaching its climax at or near the close with

A. Hallam

1969-01-01

240

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…

Peacock, Alan

2007-01-01

241

Origin of the Pacific Jurassic quiet zone  

Microsoft Academic Search

Understanding the marine magnetic anomaly record is critical for constructing realistic geodynamo models of global geomagnetic field, polarity reversal mechanisms, and long-term geomagnetic field behavior. One of the least understood portions of the marine magnetic anomaly record is also the oldest part of the record, the Jurassic quiet zone (JQZ), where anomalies become weak and difficult to correlate. The reason

Maurice A. Tivey; William W. Sager; Sang-Mook Lee; Masako Tominaga

2006-01-01

242

Navajo Master Health Plan, 1979-1983. Arizona Health Service Area 4. Native Healing Services.  

National Technical Information Service (NTIS)

Native Healing Services is an issue that relates to the unique and diverse Navajo health care system, a blend of traditional and modern influences, are broadly examined in the Native Healing component. Culturally derived attitudes, values and beliefs grea...

1982-01-01

243

Navajo Health Systems Agency: Native Healing Services, 1982. Arizona Health Service Area 4.  

National Technical Information Service (NTIS)

Issues relating to the unique and diverse Navajo health care system, a blend of traditional and modern influences, are broadly examined in the Native Healing component. Culturally derived attitudes, values and beliefs greatly affect the use and delivery o...

1982-01-01

244

Breast Cancer Education for Navajo Women: a Pilot Study Evaluating a Culturally Relevant Video  

PubMed Central

This pilot study evaluated a culturally specific video designed to teach Navajo women about breast cancer treatment options. Fourteen Navajo women diagnosed with breast cancer and 26 healthcare providers participated in a mixed-method evaluation that documented their perceptions immediately and 6 months after viewing the video. After initial viewing, women reported reduced anxiety about treatment and interest in support groups. Six months later, women said the video prompted them to seek more information from printed sources and their provider. Younger Navajo women who were 44 to 51 years old were more likely to attend support groups than women who were 55–67 years. Providers corroborated the positive effects of the video. The providers believed the video encouraged patients to seek information about breast cancer and to ask questions about treatment plans and side effects. A culturally relevant video for Navajo women can be an effective teaching tool and can enhance patient–provider communication.

Teufel-Shone, Nicolette I.; Baldwin, Julie A.; Sandoval, Nellie; Robinson, Frances

2010-01-01

245

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

246

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

Federal Register 2010, 2011, 2012, 2013

...Reduction Act of 1995, the Bureau of Indian Affairs (BIA) is seeking comments...CFR 161, implementing the Navajo-Hopi Indian Relocation Amendments Act of 1980...S. 758 (1963) (Healing II), Hopi Tribe v. Watt, 530 F. Supp....

2013-05-29

247

Financial Review of the Navajo and Hopi Indian Relocation Commission June 30, 1976.  

National Technical Information Service (NTIS)

The report contains a financial review for 1976 of a commission established to relocate members of the Navajo and Hopi Indian tribes who were required to move because of a land dispute on the Reservation. Problems discussed include commissioners salaries,...

1977-01-01

248

Indian Relocation: Navajo and Hopi Indian Relocation Commission Estimated Relocation Cost.  

National Technical Information Service (NTIS)

The fact sheet contains information on the Navajo and Hopi Indian Relocation Commission's activities. It provides the number of Indian families to be relocated, a breakout of the actual and estimated relocation costs, the Commission's replacement-home ben...

1985-01-01

249

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

Federal Register 2010, 2011, 2012, 2013

...Reduction Act of 1995, the Bureau of Indian Affairs (BIA) is seeking comments...part 161, implementing the Navajo- Hopi Indian Relocation Amendments Act of 1980...S. 758 (1963) (Healing II), Hopi Tribe v. Watt, 530 F. Supp....

2013-03-08

250

Gas play opportunities in deeper Jurassic sequences of the Neuquen basin embayment, Argentina  

SciTech Connect

We have defined new gas plays at around 4000 m depth near the giant Loma La Lata gas field. The plays, in lower Jurassic sandstones, were developed using a different approach in stratigraphic signatures as well as deformation styles. Two initial rifting stages led to the Triassic-Early Liassic volcanoclastic deposition (Precuyo s.l.) into a suite of discrete half-grabens. The late rifting stage amalgamated the Precuyo depocenters into notably extended subsiding half-grabens where the Pliensbachian-Toarcian deposits were accommodated. This lower Cuyo sequence-set (LC) consists of basinal marine shales (Molles Formation) and a progradational stacking of slope and shelf sandstones (Lajas Formation), bearing a kerogen type III-II within the gas window with TOC values range 2-6%. The LC top matches with a conspicuous regional unconformity related to the thermo-mechanic subsidence. The overlying Bajocian-early Callovian upper Cuyo sequence set exhibits outer shelf argillaceous sediments at the base. The identified plays are related to two deformation mechanisms: mud diapirism and tectonic inversion. The thick, rapidly deposited LC sandstones triggered the ductile flow of the underlying, overpressured shales. Soon after, the tectonic inversion of the Precuyo half-grabens produced a series of aligned anticlines parallel to Huincul Arch. Scattered incipient diapirism toward the embayment resulted in dome-like structures. Sandstones with gas shows could act as {open_quotes}tight gas reservoirs.{close_quotes} However, increased permeability through natural fracturing in the structures would increase their viability. The estimated resources of several TCF in untested closures and the industry infrastructure make these plays particularly attractive for gas exploration.

Fernandez-Seveso, F.; Figueroa, D.E.; Rodriguez, H. [YPE, S.A., Buenos Aires (Argentina)

1996-08-01

251

Uranium Mining on the Navajo Indian Reservation: An Environmental Examination of the Process and Impact  

Microsoft Academic Search

Uranium mining on the Navajo Reservation created an environmental justice disaster which has strangely helped bring the Navajo Nation to achieve considerable self-determination within the United States.\\u000aThe United States’ need for uranium to fuel the nuclear weapons and energy program brought the Atomic Energy Commission to establish an extensive mining operation on Southwestern edge of the Colorado Plateau. Many

Caitlin A McElroy

2006-01-01

252

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

253

Quantitative analysis of sandstone porosity  

SciTech Connect

A quantitative analysis of changes in porosity associated with sandstone diagenesis was accomplished with digital back-scattered electron image analysis techniques. The volume percent (vol. %) of macroporosity, quartz, clay minerals, feldspar, and other constituents combined with stereological parameters, such as the size and shape of the analyzed features, permitted the determination of cement volumes, the ratio of primary to secondary porosity, and the relative abundance of detrital and authigenic clay minerals. The analyses were produced with a JEOL 733 Superprobe and a TRACOR/NORTHERN 5700 Image Analyzer System. The results provided a numerical evaluation of sedimentological facies controls and diagenetic effects on the permeabilities of potential reservoirs. In a typical application, subtle differences in the diagnetic development of porosity were detected in Wilcox sandstones from central Louisiana. Mechanical compaction of these shoreface sandstones has reduced the porosity to approximately 20%. In most samples with permeabilities greater than 10 md, the measured ratio of macroporosity to microporosity associated with pore-filling kaolinite was 3:1. In other sandstones with lower permeabilities, the measured ratio was higher, but the volume of pore-filling clay was essentially the same. An analysis of the frequency distribution of pore diameters and shapes revealed that the latter samples contained 2-3 vol% of grain-dissolution or moldic porosity. Fluid entry to these large pores was restricted and the clays produced from the grain dissolution products reduced the observed permeability. The image analysis technique provided valuable data for the distinction of productive and nonproductive intervals in this reservoir.

Ferrell, R.E. Jr.; Carpenter, P.K.

1988-01-01

254

Prevalence of gestational diabetes in a Navajo Indian community.  

PubMed Central

A retrospective analysis of 4,094 deliveries among Navajo Indian women was carried out to determine the prevalence of gestational diabetes mellitus and diabetes antedating pregnancy. Three data sources--a local prenatal registry, a delivery room log, and hospital discharge records--were evaluated for their usefulness as surveillance systems for gestational diabetes. In all, 177 cases of gestational diabetes and 13 cases of preexisting diabetes were identified, giving a prevalence of maternal diabetes in pregnancy of 4.6%. When women with preexisting diabetes or documented gestational diabetes during a previous pregnancy were excluded, the prevalence of gestational diabetes during the study period was 3.4%. Although each data source used separately failed to identify 20% to 40% of diabetic pregnancies, more than 97% of cases were identified using a combination of the prenatal registry and the delivery log.

Sugarman, J R

1989-01-01

255

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

256

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

SciTech Connect

In January 2012, the National Renewable Energy Laboratory delivered to the Department of the Interior the first part of a study on Navajo Generating Station (Navajo GS) and the likely impacts of BART compliance options. That document establishes a comprehensive baseline for the analysis of clean energy alternatives, and their ability to achieve benefits similar to those that Navajo GS currently provides. This analysis is a supplement to NREL's January 2012 study. It provides a high level examination of several clean energy alternatives, based on the previous analysis. Each has particular characteristics affecting its relevance as an alternative to Navajo GS. It is assumed that the development of any alternative resource (or portfolio of resources) to replace all or a portion of Navajo GS would occur at the end of a staged transition plan designed to reduce economic disruption. We assume that replacing the federal government's 24.3% share of Navajo GS would be a cooperative responsibility of both the U.S. Bureau of Reclamation (USBR) and the Central Arizona Water Conservation District (CAWCD).

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

2012-06-01

257

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

PubMed Central

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

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

2011-01-01

258

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

SciTech Connect

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

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

1985-06-01

259

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

260

Pelahatchie: the geologist's Jurassic problem child  

Microsoft Academic Search

An unusually high-pressure oil well was tested from the Norphlet sand of Jurassic age in Rankin County, Miss. This 17,000-ft well had been drilled in the same 40-acre tract as the original Lower Cretaceous discovery well of Pelahatchie field. This field is situated in the updip belt of Lower Cretaceous oil production and in the downdip belt of Smackover production.

Karges

1968-01-01

261

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

USGS Publications Warehouse

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

Lillis, Paul G.; King, J. David

2007-01-01

262

Impact Crater Identified on the Navajo Nation Near Chinle, Arizona  

NASA Astrophysics Data System (ADS)

A small impact crater has been identified about 8 km north of Chinle, Arizona on the Navajo Nation. Preliminary studies show that the crater is elongate in a N-S direction, measuring about 23 by 34 m in diameter, with a depth of about 1.3 m. The impact origin of the crater is identified by its shape, subsurface deformation, and an iron-nickel oxide fragment. We estimate the age to be about 150 to 250 years. The impact site is on the east side of the Chinle Valley at an altitude of 1685 m and is about 2 km east of Chinle Wash. The crater formed on an alluvial surface that slopes gently west toward the Wash. About 2 m of reddish brown alluvial sand and silt of the Jeddito Formation of late Pleistocene age rests on the Petrified Forest Member of the Chinle Formation of late Triassic age. A moderately developed late Pleistocene pedocal soil has developed on the Jeddito. Several thin discontinuous caliche horizons occur at a depth of about 1 m. The caliche horizons provided easily traced markers by which we could delimit the original walls of the crater and recognize deformation along the crater walls. Three trenches were excavated down to the top of the Chinle bedrock: 1) an east- west trench 31 m long across the center of the crater, 2) a north-south trench 13 m long in the north crater rim, and 3) a north-south trench 12 m long in the south crater rim. Excavation width was about 1 m and provided excellent exposures of the subsurface stratigraphy and deformation. The trenches revealed that the original crater was about 23 m wide and 27 m long. The original rim crests have entirely eroded away so that no perceptible raised rim remains. At the center of the crater, the original depth was about 3 m; material washed from the rims now fills the crater floor to a depth of 1.5 m. The crater is symmetrical; however, the deepest part of the original crater lies south of the center and was not reached in the south trench. The east-west trench showed that the initial floor of the crater was scoured down to the Jeddito-Chinle contact across the center of the crater. Some of the Chinle was excavated by impact south of the center, as seen in the trench in the south wall. The original crater walls slope inward about 30 degrees on the east and west sides, about 20 degrees on the north, and about 45 degrees on the south. Beds are dragged up along the east, west, and south walls, but not along the north wall. The deformation is restricted to within about 0.5 m of the wall. From the asymmetry of shape and deformation in the walls, we believe that the impacting body struck at an oblique angle and was traveling from north to south. A small, magnetic, iron oxide fragment, about 1 mm across, was collected from material excavated from the south crater wall area. Analyses of this fragment by electron microprobe detected a significant nickel concentration of 5%. Two senior Navajo women (70-80 year age range) independently remember this crater as being much deeper during their childhood and both suggest that the impact was witnessed 3 to 4 generations ago. Interestingly, many persons in the Navajo community thought that this crater was of impact origin. Additional work is planned, including a broader aerial search for other possible impact sites.

Shoemaker, E. M.; Roddy, D. J.; Moore, C. B.; Pfeilsticker, R.; Curley, C. L.; Dunkelman, T.; Kuerzel, K.; Taylor, M.; Shoemaker, C.; Donnelly, P.

1995-09-01

263

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

SciTech Connect

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

Torres, L.F.

1989-03-01

264

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

265

Exploration models for submarine slope sandstones  

Microsoft Academic Search

Recent published studies have demonstrated a far greater potential than previously recognized for submarine slope sandstones to contain significant oil and gas reserves in the Gulf Coast and elsewhere. Comparison of modern slopes with outcrop and subsurface analogs from several areas provided the framework for developing the following submarine slope sandstone exploration models: submarine canyon fill, slope gully\\/channel fill, slope

Slatt

1986-01-01

266

Thorium and uranium contents of some sandstones  

Microsoft Academic Search

Average values have been obtained by gamma-ray spectrometry for the thorium and uranium contents of some orthoquartzites and graywackes. The Atoka and Jackfork quartz sandstones of western Arkansas average approximately 4 ppm thorium and 1 ppm uranium. The Umpqua and Tyee graywackes of western Oregon average approximately 7 ppm thorium and 2 ppm uranium. Weighted average concentrations for all sandstones

John J. W. Rogers; Keith A. Richardson

1964-01-01

267

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

268

Hematite ``Blueberry`` Concretion Doublet and Triplets on Mars: Iron Oxide Twin Analogs From Utah  

Microsoft Academic Search

Spherical concretions on Earth and Mars comprise a record of diagenetic history that may not otherwise be preserved in the more common host rock. Hematite spherules of Meridiani Planum show some joined forms of twos and threes. Joined iron oxide concretions making doublets and triplets also occur in the Jurassic Navajo Sandstone of southern Utah, and can serve as an

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

2005-01-01

269

Upper Jurassic Norphlet formation: new frontier for hydrocarbon prospecting in the central and eastern Gulf of Mexico regions  

SciTech Connect

Since the discovery of oil in 1967 from the Smackover Formation at Toxey field, Choctaw County, Alabama, and of condensate in 1968 from the Norphlet Formation at Flomaton field, Escambia County, Alabama, the Upper Jurassic has become the primary exploration target in southwestern Alabama. Norphlet petroleum traps in the region are principally combination traps involving favorable stratigraphy and salt anticlines (Copeland field), exensional fault traps associated with salt movement (Flomaton field), and faulted salt anticlines (Hatter's Pond and Lower Mobile Bay-Mary Ann fields). Reservoir rocks include marine, dune, and fluvial sandstone lithofacies. Sandstone porosity involves both primary intergranular and secondary dissolution and fracture. Smackover algal carbonate mudstone is probably the source for much of the Norphlet hydrocarbon, but downdip Norphlet marine shales may also be source rocks. The central and eastern Gulf of Mexico regions should continue to be excellent areas to explore for hydrocarbons in the years ahead. Successful Norphlet petroleum prospecting in the area has involved the identification of favorable sandstone lithofacies and structural hydrocarbon traps by using geologic and geophysical methods. Future Norphlet discoveries will require the delineation of stratigraphic and structural/stratigraphic combination hydrocarbon traps using seismic-stratigraphic techniques.

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

1984-04-01

270

Upper Jurassic Norphlet formation: new frontier for hydrocarbon prospecting in the central and eastern Gulf of Mexico regions  

SciTech Connect

Since the discovery of oil in 1967 from the Smackover Formation at Toxey field, Choctaw County, Alabama, and of condensate in 1968 from the Norphlet Formation at Flomaton field, Escambia County, Alabama, the Upper Jurassic has become the primary exploration target in southwestern Alabama. Norphlet petroleum traps in the region are principally combination traps involving favorable stratigraphy and salt anticlines (Copeland field), extensional fault traps associated with salt movement (Flomaton field), and faulted salt anticlines (Hatter's Pond and Lower Mobile Bay-Mary Ann fields). Reservoir rocks include marine, dune, and fluvial sandstone lithofacies. Sandstone porosity involves both primary intergranular and secondary dissolution and fracture. Smackover algal carbonate mudstone is probably the source for much of the Norphlet hydrocarbon, but downdip Norphlet marine shales may also be source rocks. The central and eastern Gulf of Mexico regions should continue to be excellent areas to explore for hydrocarbons in the years ahead. Successful Norphlet petroleum prospecting in the area has involved the identification of favorable sandstone lithofacies and structural hydrocarbon traps by using geologic and geophysical methods. Future Norphlet discoveries will require the delineation of stratigraphic and structural/stratigraphic combination hydrocarbon traps using seismic-stratigraphic techniques.

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

1984-04-01

271

Diabetes mellitus in Hopi and Navajo indians. Prevalence of microvascular complications.  

PubMed

In a cross-sectional study of Hopi and Navajo Indians with non-insulin-dependent diabetes mellitus, we found vascular complications to be strongly related to the duration of diabetes. In patients with diabetes of at least 10 yr duration, retinopathy was found in 57%, nephropathy in 40%, peripheral neuropathy in 21%, and peripheral vascular disease in 28%. For the Hopi and Navajo, the duration-specific prevalence rates of microvascular disease were very similar to prevalence rates found in many other populations. Thus we question the concept, based on reports in the late 1960s, that the Hopi and Navajo Indians have hyperglycemia as an isolated chemical abnormality unaccompanied by other manifestations of diabetes mellitus. PMID:6618018

Rate, R G; Knowler, W C; Morse, H G; Bonnell, M D; McVey, J; Chervenak, C L; Smith, M G; Pavanich, G

1983-10-01

272

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

PubMed Central

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

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

1981-01-01

273

Diabetes on the Navajo nation: what role can gardening and agriculture extension play to reduce it?  

PubMed

Diabetes has emerged as a serious health problem in the Navajo nation, the largest Indigenous tribe in the US. Persons with diabetes are at greater risk for developing other diseases such as cardiovascular disease. Navajos with diabetes almost certainly face a diminished quality of life if their diabetes is not managed properly. Aside from genetics, the incidence of diabetes is highly correlated with income, poor diet, and limited physical exercise. A review of the literature also implicates dietary shifts initiated by historical events and contemporary trends. Numerous studies have shown that moderate consumption of fruits and vegetables, combined with exercise, reduces the risk of or delays the onset of many diseases including diabetes. As part of a larger holistic approach, home and community garden projects have successfully addressed nutrition and food security issues on a grassroots scale. The Navajos have a tradition of farming and therefore expanding Navajo diabetes interventions to include the promotion of community and home gardens provides multiple opportunities. The benefits of these actions include: (i) a variety of nutritious food grown locally; (ii) physical activity attained through the act of daily gardening tasks; (iii) positive income garnered in terms of savings in food otherwise purchased at stores and excess produce canned, or if desired, sold at a farmer's market or trading post; and (iv) positive mental outlook through a combined sense of accomplishment at harvest time, bonding with the earth, and spiritual growth. The objectives of this article were to review the development of diabetes on the Navajo nation though historical and contemporary literature, to provide insight into the role of diet and exercise in the progression of the disease, and to offer cases and suggestions in the role that home and community gardening can play in diabetes reduction. A concluding discussion proposes a multidisciplinary approach to tackling diabetes on the Navajo nation involving public health officials, nutritionists, and horticultural extension agents that could also be applied internationally in similar multicultural, semi-arid climates. PMID:17044752

Lombard, Kevin A; Forster-Cox, Susan; Smeal, Dan; O'Neill, Mick K

2006-10-16

274

Evidence for Late Jurassic release of methane from gas hydrate  

Microsoft Academic Search

Four Late Jurassic carbonate successions deposited in the Tethys-Atlantic Ocean record a negative carbon isotope excursion of at least 20\\/00. The excursion is present in both organic and carbonate carbon records and is comparable in magnitude and duration to isotopic changes during the late Paleocene thermal maximum. Our results indicate that during the Late Jurassic, long considered a warm greenhouse

Maureen Padden; Helmut Weissert; Marc de Rafelis

2001-01-01

275

Triassic\\/Jurassic faulting patterns of Conecuh Ridge, southwest Alabama  

Microsoft Academic Search

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,

Hutley

1985-01-01

276

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

277

The Jurassic of the Circum-Pacific  

NASA Astrophysics Data System (ADS)

In this work, sixty specialists assembled to discuss the regional occurrences of Jurassic rocks around the Pacific rim. The tectonic setting, stratigraphical sequences, and fossil assemblages of the region are covered in detail; regional biozones based on palynonorphs, protistans, plants and invertebrates are defined; and super-regional standard zones based on ammonites are established. Numerous tables are used to document and illustrate intra- and intercontinental circum-Pacific correlations, and a large atlas illustrates more than 1,000 circum-Pacific index fossils.

Westermann, Gerd E. G.

1993-03-01

278

The Jurassic of Denmark and Greenland: key elements in the reconstruction of the North Atlantic Jurassic rift system  

Microsoft Academic Search

The Jurassic succession of Denmark is largely confined to the subsurface with the exception of exposures on the island of Bornholm in the Baltic Sea. In East Greenland, in contrast, the Jurassic is extensively exposed. Comparison of basin evolution in the two regions, which now occur on two separate plates, thus relies on highly different datasets. It is possible nevertheless

Finn Surlyk; Jon R. Ineson

2003-01-01

279

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

280

Systematic Palaeontology (Vertebrate Palaeontology) A basal sauropod dinosaur from the Early Jurassic of Morocco  

Microsoft Academic Search

Continental strata of Early Jurassic age are seldom exposed, and little is known of the history of sauropod dinosaurs prior to the Middle Jurassic radiation of neosauropods. Well-preserved skeletons and skulls have not been recovered from strata older than the Middle Jurassic. Here we report, in the Early Jurassic of the Moroccan High Atlas, the discovery of the skeleton, including

Ronan Allain; Najat Aquesbi; Jean Dejax; Christian Meyer; Michel Monbaron; Christian Montenat; Philippe Richir; Mohammed Rochdy; Dale Russell; Philippe Taquet

281

Elastic envelopes of porous sandstones  

NASA Astrophysics Data System (ADS)

In this paper we focus on the case of sandstones for which many experimental data are available. We present a simple 2?D model derived from granular media mechanics. This model assumes that the granular microstructure is a key point to understand the mechanical behavior. We consider a periodic grain network and focus on the first?order neighbors of a given grain. These approximations are sufficient to explain the overall mechanical behavior in the Q versus P stress space. In the low pressure range, the controlling micromechanism is assumed to be tensile failure at grain contacts. The "dilatant" envelope is found to be a straight line in the stress space. In the high pressure range, the controlling micromechanism is assumed to be grain fragmentation. The "compactant" envelope is found to be a straight line in the stress space. We observed that this 2?D model slightly overestimates Q versus P slopes determined experimentally (2.3 instead of 1.5), which can be explained by the approximations made.

GuéGuen, Yves; Fortin, JéRôMe

2013-07-01

282

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

283

Navajo Safety of Dams Project: Photographic Documentation of Round Rock Dam, Apache County, Arizona.  

National Technical Information Service (NTIS)

Round Rock Dam, located on the Navajo Reservation, was evaluated and determined eligible for nomination to the National Register of Historic Places as part of a safety of dams project. The dam is an off-stream, rolled, homogeneous earthfill embankment typ...

W. G. White

1994-01-01

284

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

285

Playing Games or Learning Science? An Inquiry into Navajo Children's Science Learning  

Microsoft Academic Search

Consideration of the subtleties in a group of Navajo children's science learning activities provides us with some useful ways of viewing those activities. It also more clearly establishes the elements to consider in valuing or not valuing the use of these kinds of activities that I am calling \\

Diana Beck

286

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…

McCarty, T. L.; And Others

287

BOARDING AND PUBLIC SCHOOLS: NAVAJO EDUCATIONAL ATTAINMENT, CONDUCT DISORDER, AND ALCOHOL DEPENDENCY  

Microsoft Academic Search

Many critics of United States government operated boarding schools for American Indians have asserted that the boarding school experience has lasting deleterious effects on personality development. Specifically, it has been suggested that a boarding school education is likely to lead to problems with alcohol in adulthood. To examine that assertion, data from interviews with over 1000 Navajos are analyzed concerning

Eric Henderson; Stephen J. Kunitz; K. Ruben Gabriel; Aaron McCright; Jerrold E. Levy

288

Rates and Causes of End-Stage Renal Disease in Navajo Indians, 1971-1985  

PubMed Central

The rates of end-stage renal disease are much increased in American Indians, but no longitudinal study of its rates and causes has been undertaken in any tribe. This 15-year study of rates and causes of treated end-stage renal disease in the Navajo, the largest Indian tribe, supplies an important model on which to base projections and plan interventions. Treated end-stage renal disease in Navajos has increased to an age-adjusted incidence 4 times that in whites in the United States. Diabetic nephropathy accounted for 50% of all new cases in 1985, with an incidence 9.6 times that in US whites, and was due entirely to type II disease. Glomerulonephritis caused end-stage renal disease in Navajos at a rate at least 1.8 times that in US whites and afflicted a much younger population. The predominant form was mesangial proliferative glomerulonephritis associated with an immune complex deposition. Renal disease of unknown etiology, which probably includes much silent glomerulonephritis, accounted for 20% of all new cases. The aggregate Navajo population with end-stage renal disease was 9 years younger than its US counterpart. These observations reflect the genesis of the epidemic of diabetic nephropathy afflicting many tribes. Urgent measures are needed to contain this. In addition, the etiology and control of mesangiopathic, immune-complex glomerulonephritis of unusual severity, a previously unrecognized problem, need to be addressed.

Megill, Donald M.; Hoy, Wendy E.; Woodruff, Sandra Dale

1988-01-01

289

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

ERIC Educational Resources Information Center

|The purpose of this article is to describe a group counseling model that is based on the indigenous medicine wheel as well as Navajo philosophy by which to help troubled adolescents restore harmony and balance in their lives, through establishing goals and sequential steps to accomplish these goals. The authors call this model the Goal Wheel. A…

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

2011-01-01

290

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…

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

2003-01-01

291

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

ERIC Educational Resources Information Center

|The purpose of this study was to determine if there was a gender difference in how students perceived their classroom environment on the Navajo Nation public school. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be…

Piechowski, Alta Begay

2011-01-01

292

Using the WISC-III with Navajo Children: A Need for Local Norms.  

ERIC Educational Resources Information Center

|The Wechsler Intelligence Scale for Children-Third Edition (WISC-III) was administered to 175 Navajo children at 2 reservation elementary schools. Local normative information was developed to reduce test bias associated with the English-laden content in the test. A procedure was developed for converting WISC-III scores, enabling comparison of…

McLellan, Mary J.; Nellis, Leah

2003-01-01

293

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

Code of Federal Regulations, 2013 CFR

...TRIBAL, AND EPA-ADMINISTERED UNDERGROUND INJECTION CONTROL PROGRAMS...Office, Old NAPA Auto Parts Building (Tribal Bldg. #S009-080...Nation with Respect To Its Underground Injection Control Program...Navajo Nation to Operate an Underground Injection Control Program...

2013-07-01

294

Navajo Women in the City: Lessons From a Quarter-Century of Relocation.  

ERIC Educational Resources Information Center

Contains an overall picture of urban relocation of American Indians occurring in mid-1950s; a summary of observations made in early 1970s with a sample of young Navajo women in San Francisco Bay area; and new research strategies for the 1980s which take into account changes over a quarter century of relocation. (ERB)

Metcalf, Ann

1982-01-01

295

American Indian Bilingual Education. Navajo Reading Study Progress Report No. 24.  

ERIC Educational Resources Information Center

|Bilingual education programs have been established in such Native American languages as Aleut, Yupik, Tlingit, Haida, Athabaskan, Cherokee, Lakota, Navajo, Papago, Pomo, Passamaquoddy, Seminole, Tewa, and Zuni. These programs include the: Choctaw Bilingual Education Program, Northern Cheyenne Bilingual Education Program, Lakota Bilingual…

Spolsky, Bernard

296

Preliminary Geophysical Investigations of the Ship Rock Diatreme, Navajo Nation, New Mexico  

Microsoft Academic Search

Magnetic and gravity data were collected at the Ship Rock minette neck and dikes, part of the Navajo volcanic field in the central Colorado Plateau, to investigate their subsurface structure. The deep root system of Ship Rock, an exhumed Oligocene maar-diatreme complex, has not been resolved. The diatreme is largely composed of minette tuff-breccia with a large wallrock fraction, whereas

E. M. Gruen; L. McCarthy; G. Namingha; C. Bank; J. Noblett; S. Semken

2003-01-01

297

Coal leasing in the Fourth World: Hopi and Navajo coal leasing, 1954-1977  

Microsoft Academic Search

Between 1954 and 1977 the Hopi and Navajo tribes sold concessions to non-Indian companies for the exploration and development of reservation lands in Arizona and New Mexico containing steam coal. This dissertation explains the preferential hiring, environmental, and financial provisions in these concessions - especially the structural response to contingencies. It builds an explanation upon conditions in the regional coal-lease

1985-01-01

298

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

SciTech Connect

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

Bezalel c. Haimson

2005-06-10

299

Paleomagnetic evidence for Post-Jurassic stability of southeastern Mexico: Maya Terrane  

NASA Astrophysics Data System (ADS)

The tectonic evolution of southeastern Mexico has been a subject of major controversy, not only in regard to past geometry but also in the timing of proposed geological events as well. For the past 10 years, most, if not all, investigators agree that the Gulf of Mexico Basin was formed by Late Jurassic time and that the Maya Terrane was in its current location prior to the Cretaceous. In order to gain further insight into the drift history of the Maya Terrane we have undertaken a paleomagnetic study of the uppermost Jurassic-Lower Cretaceous (Tithonian-lower Neocomian?) San Ricardo Formation in southeastern Mexico, at 93.7°W, 16.8°N. The sampling site is located east of the Isthmus of Tehuantepec, on the southwest side of the Maya block, at the base of the Yucatan Peninsula. A suite of 133 samples was collected in stratigraphic succession from a 114-m-thick sequence of red shales and sandstones near Cintalapa, Chiapas, Mexico. After progressive thermal demagnetization of all samples at six steps from 350°C to 630°C, 89 samples were selected for final paleopole analysis on the basis of their magnetic stability. Four different polarity intervals were observed, the sequence being from bottom to top: N, R, N, R which assists in the assessment of the reliability of the observations. The mean pole position obtained, 160.0°E, 69.8°N, agrees with the mean pole position of the upper part of the Morrison Formation of Colorado, a unit of virtually identical age. These results indicate that no discernible rotation or displacement of the Maya block has occurred since at least early Neocomian times.

Guerrero, Jose C.; Herrero-Bervera, Emilio; Helsley, Charles E.

1990-05-01

300

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); Rind, D.; Ruedy, R. [Goddard Institute for Space Studies, New York, NY (United States)

1992-05-01

301

Navajo Garnetites and Rock-Water Interactions in the Mantle  

NASA Astrophysics Data System (ADS)

Garnetite xenoliths from ultramafic diatremes in northeastern Arizona provide insights into mantle-water interactions. The garnetites are more than 95% garnet with subequal proportions of Grs, Alm, and Prp. Accessory minerals include rutile, ilmenite, chlorite, clinopyroxene, and zircon. Textures and mineral compositions are consistent with garnetite formation by hydrous metasomatism at about 500° C near contacts between mafic rocks and peridotite. Trace element abundances and isotope ratios measured by LA-ICP-MS and -MC-MS document xenolith histories. Typical garnets are slightly enriched in MREE relative to HREE, and small positive Eu anomalies are present in garnet of one xenolith. Zircon shapes in one garnetite are diverse. Most U-Pb analyses of these zircons plot on or near concordia in the range 60 to 85 Ma, but analyses of several grains lie off concordia, and chords between these discordant results and the main cluster have Proterozoic upper intercepts. Hf 176/177 ranges from about 0.2818 to 0.2828, yielding depleted mantle model ages from 1.9 to 0.5 Ga that cluster at about 1.8 and 1.1 Ga. More radiogenic Hf is roughly correlated with decreasing U-Pb age in the interval 85 to 60 Ma, and zircons are zoned to more radiogenic Hf, core to rim. The high Hf 176/177 in the young zircons and zircon rims is consistent with the modelled evolution of Hf in the garnet (mean Lu/Hf about 30). These data establish that the garnetite inherited Hf and zircons from a protolith at least 1.8 Ga in age, and suggest that the garnetite itself formed around 85 Ma ago, and some zircon within it crystallized episodically during the interval 85 to 60 Ma. The zircon data eliminate the possibility that the garnetites are fragments of the Farallon plate. The time interval for garnetite crystallization overlaps the 80 to 30 Ma range recorded by zircons in typical Navajo eclogites, consistent with the hypothesis that both eclogites and garnetites record the interaction of water with Proterozoic mantle. These rocks may document movement of water into the overlying continental mantle from the Farallon plate during low-angle subduction and later mobilization of that water.

Smith, D.; Griffin, W. L.

2003-12-01

302

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

PubMed Central

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

2009-01-01

303

Paleogeography of Jurassic fragments in the Caribbean  

NASA Astrophysics Data System (ADS)

Jurassic rocks of the Caribbean are a sampling of 100 million years of Farallon Plate history with fragments originating at diverse paleolatitudes and from varied tectonic settings. Fragments with clear paleogeographic signatures are components of the basement complexes of Duarte in Hispaniola, Bermeja in Puerto Rico and La Désirade off Guadeloupe. Paleolatitudinally sensitive radiolarian faunas document origination of Duarte as equatorial, La Désirade as higher latitude, and various Bermeja cherts as both equatorial and higher latitude. Red ribbon chert of Duarte and Bermeja of the same age, physical appearance, and lithological association are probably dismembered components of the same slab of Pacific crust. La Désirade red ribbon chert is slightly younger than the Duarte and Bermeja red ribbon chert and was deposited at higher latitude. Bermeja tuffaceous chert is also of higher latitude and probably had an arc-proximal origin. On the basis of modeled plate trajectories in the Pacific, the origin of various cherts from different paleolatitudes that end up in the same location requires different arrival times at the trench between North and South America. Based on radiolarian paleobiogeography plus indications of origin at a spreading ridge and ignoring the poorly constrained, modeled trajectories for the Late Jurassic, at least one of the higher latitude fragments may have originated in the southern hemisphere. The accumulation of multifarious chert, greenstone, and other ocean floor components was accomplished by offscraping strata transported to the subduction zone along the eastern Pacific margin and warehousing this material in an accretionary complex prior to entry of the Caribbean Plate into the gap between North and South America.

Montgomery, Homer; Pessagno, Emile A.; Lewis, John F.; Schellekens, Johannes

1994-06-01

304

Origin of the Pacific Jurassic quiet zone  

NASA Astrophysics Data System (ADS)

Understanding the marine magnetic anomaly record is critical for constructing realistic geodynamo models of global geomagnetic field, polarity reversal mechanisms, and long-term geomagnetic field behavior. One of the least understood portions of the marine magnetic anomaly record is also the oldest part of the record, the Jurassic quiet zone (JQZ), where anomalies become weak and difficult to correlate. The reason for the existence of the JQZ is unclear. It has been suggested that the JQZ is a true polarity superchron, similar to the Cretaceous normal superchron. Continental magnetostratigraphic studies have suggested that the JQZ is a period of rapid polarity reversal, of low field intensity, or both. We show results of a deep-tow survey of Pacific Jurassic crust that confirms the existence of magnetic anomalies within the JQZ. We tie Ocean Drilling Program Hole 801C (167.4 Ma) into the record and show that seafloor-spreading magnetic anomalies are present around the hole and extend to 170 Ma crust. We find a rise in reversal rate with increasing age with reversal rates over 10 rev/m.y. at 160 Ma and at 167 Ma. Anomaly amplitudes decrease in the record from 155 Ma until 162 Ma, where low-amplitude anomalies are difficult to correlate. Prior to 167 Ma, anomalies regain amplitude and remain strong until the end of our record at 170 Ma. The JQZ thus appears to be a combination of low-amplitude magnetic anomalies combined with rapid field fluctuations, which could be due to either intensity or polarity changes.

Tivey, Maurice A.; Sager, William W.; Lee, Sang-Mook; Tominaga, Masako

2006-09-01

305

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

306

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

USGS Publications Warehouse

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

Whitney, G.; Northrop; H. R.

1987-01-01

307

Geology and genesis of overpressured sandstone reservoirs in Venture gas field, offshore Nova Scotia, Canada  

SciTech Connect

Overpressured formations with pressure gradients up to 1.9 times normal hydrostatic occur over an area approximately 10,000 km/sup 2/ offshore Nova Scotia, Canada. In the Venture field, the abnormal pressures are confined below 4500 m and are associated with gas- and condensate-bearing Upper Jurassic-Lower Cretaceous sandstone reservoirs. Venture overpressures differ from Gulf Coast-type overpressures in that they occur within normally compacted shales containing numerous overpressured sandstone reservoir beds. Normal compaction is indicated indirectly by gradual increase in bulk density, sonic velocity, and shale resistivity with depth. Plots of temperature gradients, organic maturation gradients, and chemical composition of formation waters vs depth across the overpressured zone also indicate normal sediment compaction. Clay mineral studies show the overpressured shales are well indurated, with the transformation of smectite into mixed-layer clay minerals occurring 2500 m above the top of the overpressured zone. Furthermore, the overpressured sandstones exhibit textures indicative of normal compaction, with secondary porosity developed in both normally compacted and overpressured strata. The Venture represents hard-rock overpressures within normally compacted strata. As a result of a low geothermal gradient in the basin, the peak gas generation was reached late after most of the lithologies had lost their effective permeability due to progressing sediment diagenesis. Formation of diagenetic seals above the zone of peak gas generation in addition to continuing release of fluids as a result of shale diagenesis contribute to formation of overpressures, but organic matter maturation and hydrocarbon expulsion are the main driving forces behind the Venture overpressures.

Jansa, L.F.; Noguera, V.H.

1989-03-01

308

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

309

Identity and healing in three Navajo religious traditions: sa'ah naagháí bik'eh hózh [symbol: see text].  

PubMed

In this article, we elucidate how the Navajo synthetic principle sa'ah naagháí bik'eh hózh [symbol: see text] (SNBH) is understood, demonstrated, and elaborated in three different Navajo healing traditions. We conducted interviews with Navajo healers and their patients affiliated with Traditional Navajo religion, the Native American Church, and Pentecostal Christianity. Their narratives provide access to cultural themes of identity and healing that invoke elements of SNBH. SNBH specifies that the conditions for health and well-being are harmony within and connection to the physical/spiritual world. Specifically, each religious healing tradition encourages affective engagement, proper family relations, an understanding of one's cultural and spiritual histories, and the use of kinship terms to establish affective bonds with one's family and with the spiritual world. People's relationships within this common behavioral environment are integral to their self-orientations, to their identities as Navajos, and to the therapeutic process. The disruption and restoration of these relationships constitute an important affective dimension in Navajo distress and healing. PMID:11224977

Lewton, E L; Bydone, V

2000-12-01

310

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

SciTech Connect

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

May, S.R.

1985-01-01

311

Acidizing sandstone formations with fluoboric acid  

SciTech Connect

The continuing search for an effective deep-penetrating sandstone acidizing system recently has focused on fluoboric acid (HBF/sub 4/). Because this acid first must hydrolyze in water to produce HF, it was believed that deeper radial penetration of live acid could be achieved during matrix acidizing operations. However, a thorough experimental study has shown that typical formation temperatures will cause fluoboric acid to spend at a rapid rate similar to that of conventional hydrofluoric acid (HF), thereby severly limiting its usefulness in most sandstone formations. Furthermore, the same silica reprecipitation potential associated with HF acidizing is also inherent in the HBF/sub 4/ system.

Kunze, K.R.; Shaughnessy, C.M.

1983-02-01

312

Jurassic sequence stratigraphy in Mississippi interior salt basin: an aid to petroleum exploration in eastern Gulf of Mexico area  

SciTech Connect

An understanding of sequence stratigraphy of Jurassic units in onshore basins can serve as an aid to identify potential petroleum reservoir and source rocks in the eastern Gulf of Mexico area. Three depositional sequences associated with cycles of eustatic sea level change and coastal onlap have been identified in the Mississippi Interior Salt basin. Three depositional sequences probably correspond to the J2.4, J3.1, and J3.2 sequences of Vail et al for Callovian through Kimmeridgian strata. In the Mississippi Interior salt basin, the lower depositional sequence is bounded by a basal type 2 unconformity and an upper type 2 unconformity in the Callovian. This sequence includes Louann evaporites (transgressive), Pine Hill anhydrites and shales (condensed section), and Norphlet eolian sandstones (highstand regressive). The middle depositional sequence reflects relative sea level rise in the late Callovian. This sequence includes Norphlet marine sandstones and lower Smackover packstones and mudstones (transgressive), middle Smackover mudstones (condensed section), and upper Smackover grainstones and anhydrites (highstand regressive).

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

1988-02-01

313

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

314

A Giant Pliosaurid Skull from the Late Jurassic of England  

PubMed Central

Pliosaurids were a long-lived and cosmopolitan group of marine predators that spanned 110 million years and occupied the upper tiers of marine ecosystems from the Middle Jurassic until the early Late Cretaceous. A well-preserved giant pliosaurid skull from the Late Jurassic Kimmeridge Clay Formation of Dorset, United Kingdom, represents a new species, Pliosaurus kevani. This specimen is described in detail, and the taxonomy and systematics of Late Jurassic pliosaurids is revised. We name two additional new species, Pliosaurus carpenteri and Pliosaurus westburyensis, based on previously described relatively complete, well-preserved remains. Most or all Late Jurassic pliosaurids represent a globally distributed monophyletic group (the genus Pliosaurus, excluding ‘Pliosaurus’ andrewsi). Despite its high species diversity, and geographically widespread, temporally extensive occurrence, Pliosaurus shows relatively less morphological and ecological variation than is seen in earlier, multi-genus pliosaurid assemblages such as that of the Middle Jurassic Oxford Clay Formation. It also shows less ecological variation than the pliosaurid-like Cretaceous clade Polycotylidae. Species of Pliosaurus had robust skulls, large body sizes (with skull lengths of 1.7–2.1 metres), and trihedral or subtrihedral teeth suggesting macropredaceous habits. Our data support a trend of decreasing length of the mandibular symphysis through Late Jurassic time, as previously suggested. This may be correlated with increasing adaptation to feeding on large prey. Maximum body size of pliosaurids increased from their first appearance in the Early Jurassic until the Early Cretaceous (skull lengths up to 2360 mm). However, some reduction occurred before their final extinction in the early Late Cretaceous (skull lengths up to 1750 mm).

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

2013-01-01

315

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

316

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

317

Development and Pilot Evaluation of a Cancer-Focused Summer Research Education Program Navajo Undergraduate Students  

Microsoft Academic Search

This paper describes the development and pilot testing of a 10-week cancer research education program for Navajo undergraduate\\u000a students. The program was piloted at Diné College with 22 undergraduates (7 men, 15 women) in 2007 and 2008. Students completed\\u000a a pre–post program survey assessing attitudes, opinions, and knowledge about research and about cancer. The program was found\\u000a to be culturally

Edward R. Garrison; Mark C. Bauer; Brenda L. Hosley; Christi A. Patten; Christine A. Hughes; Mary A. Trapp; Wesley O. Petersen; Martha A. Austin-Garrison; Clarissa N. Bowman; Robert A. Vierkant

2010-01-01

318

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

319

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

320

Is there a basin-centered gas accumulation in Cotton Valley Group Sandstones, Gulf Coast Basin, U.S.A.?  

USGS Publications Warehouse

The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, is reevaluating the resource potential of selected domestic basin-centered gas accumulations. Basin-centered gas accumulations are characterized by presence of gas in extensive low-permeability (tight) reservoirs in which conventional seals and trapping mechanisms are absent, abnormally high or low reservoir pressures exist, and gas-water contacts are absent. In 1995, the USGS assessed one basin-centered gas play and two conventional plays within the trend of Jurassic and Cretaceous Cotton Valley Group fl uvial-deltaic and barrierisland/ strandplain sandstones across the onshore northern Gulf of Mexico Basin. Detailed evaluation of geologic and production data provides new insights into these Cotton Valley plays. Two Cotton Valley sandstone trends are identifi ed based on reservoir properties and gas-production characteristics. Transgressive blanket sandstones across northern Louisiana have relatively high porosity and permeability and do not require fracture stimulation to produce gas at commercial rates. South of this trend, and extending westward into eastern Texas, massive sandstones of the Cotton Valley trend exhibit low porosity and permeability and require fracture stimulation. The high permeability of Cotton Valley blanket sandstones is not conducive to the presence of basin-centered gas, but lowpermeability massive sandstones provide the type of reservoir in which basin-centered gas accumulations commonly occur. Data on source rocks, including burial and thermal history, are consistent with the interpretation of potential basincentered gas within Cotton Valley sandstones. However, pressure gradients throughout most of the blanket- and massivesandstone trends are normal or nearly normal, which is not characteristic of basin-centered gas accumulations. The presence of gas-water contacts in at least seven fi elds across the blanket-sandstone trend together with relatively high permeabilities and high gas-production rates without fracture stimulation indicate that fi elds in this trend are conventional. Within the tight massive-sandstone trend, permeability is suffi ciently low that gas-water transition zones are vertically extensive and gas-water contacts either have not been encountered or are poorly defi ned. With increasing depth through these transition zones, gas saturation decreases and water saturation increases until eventually gas saturations become suffi ciently low that, in terms of ultimate cumulative production, wells are noncommercial. Such progressive increase in water saturation with depth suggests that poorly defi ned gas-water contacts probably are present below the depth at which wells become noncommercial. The interpreted presence of gas-water contacts within the tight, Cotton Valley massive-sandstone trend suggests that gas accumulations in this trend, too, are conventional, and that a basin-centered gas accumulation does not exist within Cotton Valley sandstones in the northern Gulf Basin.

Bartberger, Charles E.; Dyman, Thaddeus S.; Condon, Steven M.

2002-01-01

321

Vertical permeability estimation in heterolithic tidal deltaic sandstones  

Microsoft Academic Search

A method for estimation of vertical permeability in heterolithic tidal deltaic sandstones is proposed. Three-dimensional, stochastic, process-based models of sedimentary bedding are used to give estimates for the effective permeability of heterolithic tidal sandstone units where heterogeneities in the sandstone and mudstone components are evaluated explicitly. Subsurface core (probe permeameter) data from two contrasting reservoir intervals in the Tilje Formation,

Philip Ringrose; Kjetil Nordahl; Renjun Wen

2005-01-01

322

Fractures and stresses in Bone Spring sandstones  

SciTech Connect

This project is a collaboration between Sandia National Laboratories and Harvey E. Yates Company being conducted under the auspices of the Oil Recovery Technology Partnership. The project seeks to apply perspectives related to the effects of natural fractures, stress, and sedimentology to the simulation and production of low-permeability gas reservoirs to low-permeability oil reservoirs as typified by the Bone Spring sandstones of the Permian Basin, southeast New Mexico. This report presents the results and analysis obtained in 1989 from 233 ft of oriented core, comprehensive suite of logs, various in situ stress measurements, and detailed well tests conducted in conjunction with the drilling of two development wells. Natural fractures were observed in core and logs in the interbed carbonates, but there was no direct evidence of fractures in the sandstones. However, production tests of the sandstones indicated permeabilities and behavior typical of a dual porosity reservoir. A general northeast trend for the maximum principal horizontal stress was observed in an elastic strain recovery measurements and in strikes of drilling-induced fractures; this direction is subparallel to the principal fracture trend observed in the interbed carbonates. Many of the results presented are believed to be new information for the Bone Spring sandstones. 57 figs., 18 tabs.

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

1990-09-01

323

THORIUM, URANIUM AND POTASSIUM IN SOME SANDSTONES  

Microsoft Academic Search

Thorinm, uranium, and potassium concentrations have been determined in ; nineteen sands and sandstones by gamma -ray spectrometry, fluorometric uranium ; analysis, and alpha counting. The samples were selected so that both common ; and extreme thorium and uranium ratios would be represented. The average and ; nearly uniform values found in orthoquartzitic, clay-free sands were potassium ; (as metal)

E. G. Murray; J. A. S. Adams

1958-01-01

324

Thorium, uranium and potassium in some sandstones  

Microsoft Academic Search

Thorium, uranium, and potassium concentrations have been determined in nineteen sands and sandstones by -ray spectrometry, fluorometric uranium analysis, and -counting. The samples were selected so that both common and extreme thorium and uranium ratios would be represented. The average and nearly uniform values found in orthoquartzitic, clay-free sands were potassium (as metal) 0.64 ± 0.04 per cent ; thorium

Elaine G. Murray; John A. S. Adams

1958-01-01

325

Stratigraphic and structural configuration of the Navajo (Jurassic) through Ouray (Mississippian-Devonian) formations in the vicinity of Davis and Lavender Canyons, southeastern Utah  

SciTech Connect

This study developed a three-dimensional computer model of stratigraphic and structural relationships within a 3497-km/sup 2/ (1350-mi/sup 2/) study area centered on the proposed site for a high-level nuclear waste repository in southeastern Utah. The model consists of a sequence of internally reconciled isopach and structure contour maps horizontally registered and stored in stratigraphic order. This model can be used to display cross sections, perspective block diagrams, or fence diagrams at any orientation; estimate depth of formation contacts and thicknesses for any new stratigraphic or hydrologic boreholes; facilitate ground-water modeling studies; and evaluate the structural and stratigraphic evolution of the study area. This study also includes limited evaluations of aquifer continuity in the Elephant Canyon and Honaker Trail Formations, and of salt dissolution and flowage features as interpreted from geophysical logs. The study identified a long history of movement in the fault system in the north-central part of the study area and a major salt flowage feature in the northeastern part. It describes the Elephant Canyon Formation aquifer as laterally limited, the Honaker Trail Formation aquifer as fairly continuous over the area, and Beef Basin in the southern part of the area as a probable dissolution feature. It also concludes that the Shay-Bridger Jack-Salt Creek Graben system is apparently a vertically continuous feature between the basement and ground surface. No stratigraphic or structural discontinuities were detected in the vicinity of Davis Canyon that appear to be detrimental to the siting of a waste repository.

McCleary, J.R.; Romie, J.E.

1986-04-01

326

Stratigraphic and Structural Configuration of the Navajo (Jurassic) Through Ouray (Mississippian-Devonian) Formations in the Vicinity of Davis and Lavender Canyons, Southeastern Utah.  

National Technical Information Service (NTIS)

This study developed a three-dimensional computer model of stratigraphic and structural relationships within a 3497-km sup 2 (1350-mi sup 2 ) study area centered on the proposed site for a high-level nuclear waste repository in southeastern Utah. The mode...

J. R. McCleary J. E. Romie

1986-01-01

327

Pleasants Sandstone Member, Williams Formation, Santa Ana Mountains: a southern California Upper Cretaceous Shelf Sandstone  

SciTech Connect

The Williams Formation consists of two distinct members: a medium to coarse-grained sandstone and conglomeratic unit (Schulz Ranch Sandstone Member), and a fine to medium-grained sandstone unit (Pleasants Sandstone member). This study of the Pleasants Sandstone Member focused on strata in a linear outcrop belt from Modjeska Grade (southeast) to Baker Canyon to Black Star Canyon (northwest). The dominantly fine-grained clayey sandstones of the Pleasants are interbedded with numerous medium to coarse-grained sandstone beds. The lack of clay minerals, the medium to coarse-grained texture, rarity of microfossils, primary sedimentary structures, transported shell materials, numerous escape burrows, and the thickness of individual units suggest that these strata were deposited rapidly, as tempestites on a narrow shelf. The intensity and duration of storm activity determined the thickness of units, as well as their preservability. Most of this sediment influx came from the vicinity of Modjeska Grade, the study section interpreted as having been in the shallowest part of the Pleasants paleoenvironment. The fine-grained clayey sandstones become progressively more dominant toward Black Star Canyon. These strata represent sediments deposited by waning storm activity, as well as hemipelagic sedimentation. These rocks exhibit a complete range of biologically to physically dominated sedimentologic fabrics, production of which depended on sedimentation rates, infaunal organism densities, and dissolved oxygen levels. Diagenetic carbonate concretions are abundant and are useful in determining the initial sediment fabric of the deposits. Carbonate concretions formed through the decomposition of abundant organic matter (plant and animal) in porous water-saturated sediments.

Enzweiler, E.J.; Bottjer, D.J.

1986-04-01

328

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

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

329

Harvestmen (arachnida: opiliones) from the middle Jurassic of China.  

PubMed

Harvestmen (Arachnida: Opiliones) are familiar animals in most terrestrial habitats but are rare as fossils, with only a handful of species known from each of the Palaeozoic, Mesozoic, and Cenozoic eras. Fossil harvestmen from Middle Jurassic (ca. 165 Ma) strata of Daohugou, Inner Mongolia, China, are described as Mesobunus martensi gen. et sp. nov. and Daohugopilio sheari gen. et sp. nov.; the two genera differ primarily in the relative length of their legs and details of the pedipalps. Jurassic arachnids are extremely rare and these fossils represent the first Jurassic, and only the fourth Mesozoic, record of Opiliones. These remarkably well-preserved and modern-looking fossils are assigned to the Eupnoi, whereby M. martensi demonstrably belongs in Sclerosomatidae. It thus represents the oldest record of a modern harvestman family and implies a high degree of evolutionary stasis among one of the most widespread and abundant groups of long-legged, round-bodied harvestmen. PMID:19495718

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

2009-06-03

330

Shallow marine syn-rift sedimentation: Middle Jurassic Pelion Formation, Jameson Land, East Greenland  

Microsoft Academic Search

The Middle Jurassic Pelion Formation - Fossilbjerget Formation couplet of Jameson Land, East Greenland, is a well-exposed example of the Middle Jurassic inshore-offshore successions char- acteristic of the rifted seaways in the Northwest European - North Atlantic region. Early Jurassic deposition took place under relatively quiet tectonic conditions following Late Permian - earli- est Triassic and Early Triassic rift phases

Michael Engkilde; Finn Surlyk

331

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

332

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

333

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

ERIC Educational Resources Information Center

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

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

334

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

335

Bureau of Indian Affairs Safety of Dams Program. 1996 Initial SEED Examination Report, Window Rock Dam, Navajo Indian Reservation, Arizona Bureau of Indian Affairs.  

National Technical Information Service (NTIS)

Window Rock Dam is located on an unnamed tributary to Black Creek within the Navajo Indian Reservation about one-half mile east of the Navajo Headquarters in Window Rock, Arizona. This report is the product of a formal onsite examination of Window Rock Da...

K. Gagner

1997-01-01

336

Low intensity of the geomagnetic field in early Jurassic time  

USGS Publications Warehouse

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

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

1991-01-01

337

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

2010-07-29

338

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

339

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

340

Isotopic fractionation of uranium in sandstone  

USGS Publications Warehouse

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

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

1963-01-01

341

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

PubMed

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

Griffin-Pierce, T

1997-01-01

342

Latest Jurassic-early Cretaceous regressive facies, northeast Africa craton  

Microsoft Academic Search

Nonmarine to paralic detrital deposits accumulated in six large basins between Algeria and the Arabo-Nubian shield during major regression in latest Jurassic and Early Cretaceous time. The Ghadames Sirte (north-central Libya), and Northern (Egypt) basins lay along the cratonic margin of northeastern Africa. The Murzuk, Kufra, and Southern (Egypt) basins lay in the south within the craton. Data for reconstructing

van Houten

1980-01-01

343

Upper Jurassic depositional systems and hydrocarbon potential of southeast Mississippi  

Microsoft Academic Search

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

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

1987-01-01

344

Hydrothermal venting of greenhouse gases triggering Early Jurassic global warming  

Microsoft Academic Search

The climate change in the Toarcian (Early Jurassic) was characterized by a major perturbation of the global carbon cycle. The event lasted for approximately 200,000 years and was manifested by a global warming of ?6 °C, anoxic conditions in the oceans, and extinction of marine species. The triggering mechanisms for the perturbation and environmental change are however strongly debated. Here, we present

Henrik Svensen; Sverre Planke; Luc Chevallier; Anders Malthe-Sørenssen; Fernando Corfu; Bjørn Jamtveit

2007-01-01

345

The ammonite succession in the Middle Jurassic o£ East Greenland  

Microsoft Academic Search

The ammonite sequence in the Middle Jurassic of central East Greenland is the most complete and detailed known in the Arctic so far, and has become a standard of reference for the whole of the Boreal Faunal Province. It is made up of some 37 distinguishable assemblages that characterize a time-ordered succession of discrete faunal horizons. This succession has been

JOHN H. CALLOMON

1993-01-01

346

Evolutionary size increase and longevity in Jurassic bivalves and ammonites  

Microsoft Academic Search

A study of the relationship between the rate of increase of size and generic or specific longevity in Jurassic ammonites and bivalves shows that taxa which increase more rapidly become extinct more quickly. The results, which can be interpreted stochastically, make it possible to distinguish two modes of evolution respectively involving an increase and decrease in size.

A. Hallam

1975-01-01

347

Exploration in Jurassic of North Mafla, eastern Gulf of Mexico  

Microsoft Academic Search

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

Kemmer

1987-01-01

348

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

349

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

350

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

351

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

352

Geology and diagenetic history of overpressured sandstone reservoirs, Venture Gas field, offshore Nova Scotia, Canada  

SciTech Connect

Deep exploratory wells in the Scotian Basin, offshore Nova Scotia, Canada, have encountered overpressured formations with pressures 1.9 {times} the normal hydrostatic gradient. The overpressures occur over an area of approximately 10,000 km{sup 2}. In the Venture field, the abnormal pressures are confined below a depth of 4,500 m and are associated with Upper Jurassic-Lower Cretaceous gas- and condensate-bearing sandstone reservoirs. The overpressures occur within normally compacted shales containing numerous overpressured sandstone reservoir beds. The development of overpressures, seals, and secondary reservoirs are all diagenetically driven. Three secondary porosity depth levels, which top at 2,500 m (65C), 3,700 m (95C), and 4,600 m (130C), correlate with major steps in the organic matter maturation in the basin. Secondary porosity is initially achieved by aluminosilicate dissolution, with ferroan sparry calcite cement dissolution dominating below 4,000 m. Porosity enhancement and preservation is not the result of a single diagenetic event but instead the result of a series of diagenetic events that overlapped in time. Formation of dynamic diagenetic barriers within the zone of peak gas generation helps retard the diffusive migration of hydrocarbons and other fluids expelled during shale diagenesis resulting in pressure build up. The preservation of up to 32% porosity under 500-1,000 atm of pressure could not be achieved without simultaneous pressuring of developing voids. Significant for hydrocarbon exploration is that Venture-type diagenetic overpressures are not associated with undercompacted sediments and, hence, they cannot be predicted from compaction trends during drilling. Petrographic diagenetic, and lithofacies studies can be instrumental in predicting potential areas of deep subsurface secondary reservoirs dependent.

Jansa, L.F. (Bedford Institute of Oceanography, Dartmouth, Nova Scotia (Canada) Dalhousie Univ., Halifax, Nova Scotia (Canada)); Urrea V.H.N. (Chevron Canada Resources, Calgary, Alberta (Canada))

1990-10-01

353

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

NASA Astrophysics Data System (ADS)

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

Scalice, D.; Carron, A.

2010-08-01

354

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

SciTech Connect

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

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

1992-01-01

355

Upper Jurassic Fossils from Ellsworth Land, West Antarctica, and notes on upper Jurassic Biogeography of the South Pacific Region  

Microsoft Academic Search

Fossils from Lyon Nunataks (74° 52? S, 74° 02? W) are described: Conodicoelites spp., Rotularia sp. indet., indet. pectinacean: cf. Entolium, and Variamussium lyonensis sp. nov. Upper Jurassic (?Lower Kimmeridgian) age. The Conodicoelites spp. have strong affinities with those of the New Zealand Lower Kimmeridgian. Ammonites, belemnites, and Inoceramus, all with strong Indo-Pacific affinities, are present in the Kimmeridgian and

G. R. Stevens

1967-01-01

356

Structural development of the Jurassic Magnetic Quiet Zone off Morocco and identification of Middle Jurassic magnetic lineations  

Microsoft Academic Search

Geophysical investigations carried out during two Meteor cruises have revealed weak linear magnetic anomalies in those parts of the Jurassic Magnetic Quiet Zone (JMQZ) off Morocco that are not affected by Cenozoic igneous activity. The linear magnetic anomalies are not correlated with variations in relief or structure of oceanic crust. Using the reversal sequence M25-M41, the anomalies of the JMQZ

H. A. Roeser; C. Steiner; B. Schreckenberger; M. Block

2002-01-01

357

Aspects of Late Triassic/Early Jurassic and Middle Jurassic fluvial sedimentation in the Viking Graben area, North Sea.  

National Technical Information Service (NTIS)

The Viking Graben of the North Sea is the site of the economically important Brent hydrocarbon province. This dissertation focuses on the nature of non-marine and coastal plain deposits of Late Triassic - Early Jurassic (Statfjord Formation) and Middle Ju...

A. Ryseth

1994-01-01

358

Combined single-grain (U-Th)\\/He and U\\/Pb dating of detrital zircons from the Navajo Sandstone, Utah  

Microsoft Academic Search

Radioisotopic dating of detrital minerals in sedimentary rocks can constrain sediment sources (provenance), elucidate episodes and rates of ancient orogenesis, and give infor- mation on paleogeography and sediment-dispersal patterns. Previous approaches have been restricted to the application of a single technique, such as U\\/Pb or fission-track dating, to detrital grains. These methods provide crystallization and cooling ages, respec- tively, of

Jeffrey M. Rahl; Peter W. Reiners; Ian H. Campbell; Stefan Nicolescu; Charlotte M. Allen

2003-01-01

359

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

360

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

361

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

USGS Publications Warehouse

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

Pollastro, Richard M.

2003-01-01

362

Sandstone acidizing design with a generalized model  

SciTech Connect

Acidizing of sandstones with HF/HCl mixtures is most frequently applied to remove near-wellbore damage, often in reservoirs with considerable vertical heterogeneity. A previously presented model for such processes in which an organic resin diverting agent was used has been extended to account for any type of particulate diverting agent and to allow for injection of multiple sequences of acid and diverting agent at either constant rates or constant bottomhole pressures (BHP's). When used to design treatments for a typical U.S. gulf coast reservoir, the model has shown that the optimal treatment strategy depends on both diverting-agent efficiency and the desired depth of live acid penetration and that relatively high injection rates appear advantageous for the conditions imposed by the model. A general model of diverting-agent behavior was developed from filtration theory. A single parameter, the specific cake resistance, is needed to model the diverting-agent behavior in the acidizing simulator. Calculation procedures to determine this parameter from laboratory tests of diverting agents were developed. These tests are either constant-rate, constant-pressure, or variable-rate and variable-pressure experiments; in each case, the specific cake resistance can be extracted from the experimental data. These procedures allow the efficiencies of various diverting agents to be compared on an equal basis. The sandstone acidizing model was used to design a treatment for a typical gulf coast sandstone reservoir. On the basis of an overall skin factor for the well, various assumptions were made about the distribution of formation damage around this multilayered completion. Treatment results were found to be fairly sensitive to the details of the damage distribution, suggesting that the skin factor alone may not be an adequate design parameter.

Taha, R.; Hill, A.D.; Sepehrnoori, K.

1989-02-01

363

Geologic aspects of reservoir souring - Brent Group sandstones, North Sea: The use of conventional and laser extraction techniques in sulfur isotope studies of authigenic pyrite  

SciTech Connect

The Middle Jurassic Brent Group sandstones are prolific oil reservoirs in the North Sea. Recently, a number of Brent wells have experienced increased levels of hydrogen sulfide contamination during production. A study involving the characterization of all iron-bearing minerals to understand the controls of mineralogy on the nature and timing of souring has been undertaken. The potential of iron minerals to scavenge hydrogen sulfide and hence delay/inhibit souring by precipitation of pyrite has been investigated by determining its distribution, quantity, and origin. Authigenic pyrite occurs as disseminated (framboidal, cubic, and octahedral) crystals and as a pore-filling cement. The pyrite has formed throughout the diagenetic history of the sandstones. however, most of the pyrite is considered to be a late cement formed during burial diagenesis. Conventional separation and sulfur isotope analysis of the authigenic pyrite was conducted on samples from oil- and water-bearing sequences to give a bulk signature for all pyrite present. Subsequently, laser sulfur isotope analysis was used to characterize the signature and origin of the different pyrite morphologies present. The enhanced level of sulfur isotope signature characterization can be used to improve the knowledge of the origin and timing of the different pyrite morphologies. This allows closer reconciliation of the isotopic data to the diagenetic history of the Brent sandstones. Calculations have been made using the known quantities of iron in these minerals and the hydrogen sulfide concentrations present. This indicates the effect of sulfide precipitation on the hydrogen sulfide levels remaining in the reservoir.

Brint, J.F. (Shell Research, Rijswijk (Netherlands)); Fallick, A.E. (Isotope Geology Univ., Glasgow (Scotland))

1991-03-01

364

Weathering of dolomitic sandstone under ambient conditions  

NASA Astrophysics Data System (ADS)

The weathering of White Mansfield dolomitic sandstone has been studied under ambient atmospheric conditions. Specially constructed sampling devices, called "micro-catchment units", were installed to sample the runoff water, i.e. the rain water that flows over the stones. In a first part of the study, the bulk run-off water was studied (some 500 samples), as well as individual particles in the runoff. The second part of the study was focussed on the stone material after three years of exposure. A whole range of modern analytical techniques has been used. An outline of the work and the results is given.

Sweevers, H.; Delalieux, F.; Van Grieken, R.

365

Campylobacter Enteritis on Hopi and Navajo Indian Reservations--Clinical and Epidemiologic Features  

PubMed Central

From June 22 through September 30, 1981, stool specimens from 522 Hopi and Navajo outpatients were cultured because of diarrheal illnesses at the Keams Canyon Indian Health Service Hospital, Arizona. Campylobacter jejuni was isolated from the specimens of 26 (5%) of the patients. This pathogen was found as frequently as Shigella in patients younger than 2 years or older than 20 years, but was significantly less common in the 2 to 20-year age group (P<.000001). Campylobacter enteritis was indistinguishable clinically from shigellosis in adult patients, but in children younger than 5 years, a rectal temperature higher than 38°C (100.5°F) was significantly more common with Shigella than with Campylobacter infection (P=.003). In a field study of 20 families, we found that households with a case of Campylobacter enteritis were more likely than age- and community-matched controls to own farm animals (P=.05), but were not more likely to own household pets. C jejuni is less common than Shigella as a cause of summer seasonal diarrhea and dysentery among the Hopi and Navajos; the striking differences in the age-specific rates of these two infections suggest different routes of transmission.

Engleberg, N. Cary; Correa-Villasenor, Adolfo; North, Charles Q.; Crow, Thomas; Wells, Joy G.; Blake, Paul A.

1984-01-01

366

Campylobacter enteritis on Hopi and Navajo Indian reservations. Clinical and epidemiologic features.  

PubMed

From June 22 through September 30, 1981, stool specimens from 522 Hopi and Navajo outpatients were cultured because of diarrheal illnesses at the Keams Canyon Indian Health Service Hospital, Arizona. Campylobacter jejuni was isolated from the specimens of 26 (5%) of the patients. This pathogen was found as frequently as Shigella in patients younger than 2 years or older than 20 years, but was significantly less common in the 2 to 20-year age group (P<.000001). Campylobacter enteritis was indistinguishable clinically from shigellosis in adult patients, but in children younger than 5 years, a rectal temperature higher than 38 degrees C (100.5 degrees F) was significantly more common with Shigella than with Campylobacter infection (P=.003). In a field study of 20 families, we found that households with a case of Campylobacter enteritis were more likely than age- and community-matched controls to own farm animals (P=.05), but were not more likely to own household pets. C jejuni is less common than Shigella as a cause of summer seasonal diarrhea and dysentery among the Hopi and Navajos; the striking differences in the age-specific rates of these two infections suggest different routes of transmission. PMID:6475040

Engleberg, N C; Correa-Villaseñor, A; North, C Q; Crow, T; Wells, J G; Blake, P A

1984-07-01

367

Diversity and paleogeographic distribution of Early Jurassic plesiosaurs  

NASA Astrophysics Data System (ADS)

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

Vincent, Peggy; Suan, Guillaume

2010-05-01

368

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

NASA Astrophysics Data System (ADS)

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

Nagy, Jenö; Hess, Silvia; Alve, Elisabeth

2010-04-01

369

Demographic Change Among the Hopi and Navajo Indians. Lake Powell Research Project Bulletin Number 2, October 1973.  

ERIC Educational Resources Information Center

|Concerned with historical patterns and with comparisons from one area to another, this report traced the growth of the Navajo and Hopi populations over the past 100 years (1870-1970). Data on fertility, mortality, and migration were obtained from the: Indian Health Service, Bureau of Indian Affairs, U.S. Public Health Service Office of Vital…

Kunitz, Stephen J.

370

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.

371

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

372

The Potential of Local Farming on the Navajo Nation to Improve Fruit and Vegetable Intake: Barriers and Opportunities  

Microsoft Academic Search

American Indian populations have low produce intake compared to other ethnic groups and higher rates of diet-related chronic diseases. Programs linking farmers to their community (Farm-to-Table) are an innovative way to alter the food environment. We interviewed Navajo farmers (n = 20), storeowners (n = 7), and non-governmental organization representatives (n = 4) to better understand local farming practices and

Ashley Setala; Sara N. Bleich; Kristen Speakman; Jane Oski; Tammy Martin; Regina Moore; Marcella Tohannie; Joel Gittelsohn

2011-01-01

373

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

ERIC Educational Resources Information Center

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

Smith, Frederick D.

1977-01-01

374

The Sun is Shining in my Eyes: The Navajo Child Enters Kindergarten Expecting to Write and He Can.  

ERIC Educational Resources Information Center

The Ganado (Arizona) Primary School, located on the Navajo Reservation, instituted a successful English writing project for kindergarten children that illustrated that young children should be allowed and expected to develop as writers because they are capable of real writing. Teachers encouraged children to complete drawings and writings in…

Boloz, Sigmund A.; Jenness, Diana

375

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

376

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

ERIC Educational Resources Information Center

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

Navajo Health Authority, Window Rock, AZ.

377

Legacy Bird Species at Risk Monitoring in and Around Camp Navajo and the Naval Observatory Flagstaff Station, AZ.  

National Technical Information Service (NTIS)

Two Department of Defense (DoD) installations, Camp Navajo Army Depot and Naval Observatory Flagstaff Station (NOFS) are located approximately 10 miles west of Flagstaff, Arizona. Arizona ponderosa pine forests are described as having a 2-20 year fire fre...

M. Ingraldi S. Blackman V. Frary

2010-01-01

378

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

Code of Federal Regulations, 2013 CFR

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

2013-04-01

379

Ship Rock Diatreme: is it a Classical Volcano? New Evidence on Magma Ascent and Emplacement Within the Navajo Volcanic Field  

Microsoft Academic Search

The Navajo Volcanic Field (NVF) is an area of late-Tertiary volcanism along the New Mexico-Arizona border near the Four Corners region of the American Southwest. Among the roughly 80 exhumed diatremes that comprise the NVF, Ship Rock and The Thumb are two diatremes that present an interesting problem concerning magma ascent and emplacement within the NVF. Are the diatremes remnants

J. R. Rotzien; B. Mayhew; S. Yospin; A. Beiki; C. Tewksbury; D. Hardman; C. Bank; J. Noblett; S. Semken; G. Kroeger

2007-01-01

380

A basal tyrannosauroid dinosaur from the Late Jurassic of China.  

PubMed

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

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

2006-02-01

381

Oolitic ironstones and contrasting Ordovician and Jurassic paleogeography  

NASA Astrophysics Data System (ADS)

Distribution of abundant Ordovician and Jurassic oolitic ironstones provides a test for current ideas about factors controlling their origin. These include warm climate and deep weathering, dispersed continents, and highstand of global sea level. Most of the Jurassic ironstones developed in middle northern latitudes on the unstable European part of assembled Laurasia at a time of low global sea level, mild moist climate, and abundant vegetation. Most of the Ordovician ironstones accumulated around the northwestern margin of assembled Gondwana and Armorica during highstand of sea level and an absence of land plants, and in high southern latitudes that supported an ice cap by the end of the period. These contrasts demonstrate that neither dispersed continents nor major highstand of sea level was a necessary factor. Moreover, requisite weathering in Ordovician time may have been induced by adequate soil-air CO2 pressure maintained by elevated atmospheric Pco2 in tne absence of land plants.

van Houten, Franklyn B.

1985-10-01

382

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

383

Ice age at the Middle–Late Jurassic transition?  

Microsoft Academic Search

A detailed record of sea surface temperatures in the Northern Hemisphere based on migration of marine invertebrate fauna (ammonites) and isotopic thermometry (?18O values of shark tooth enamel) indicates a severe cooling at the Middle–Late Jurassic transition (MLJT), about 160 Ma ago. The magnitude of refrigeration (1–3°C for lower middle latitudes) and its coincidence in time with an abrupt global-scale

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

2003-01-01

384

New discovery on dinosaur fossils from Early Jurassic, Sichuan, China  

Microsoft Academic Search

An early and primitive sauropod dinosaur,Gongxianosaurus shibeiensis (gen. et sp. nov.), from Lower Jurassic Dongyuemiao Member of Ziliujing Formation in Shibei Village, Gongxian County, Sichuan\\u000a Province, China is described, which is among Gongxian dinosaur fossils discovered in 1997. Except for skull incomplete, fossils\\u000a were well-preserved. It has concurrently some features of both sauropod and prosauropds. It is an intermediate type

Yaonan Luo; Changsheng Wang

1999-01-01

385

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

386

Magnetic lineations in the Pacific Jurassic quiet zone  

Microsoft Academic Search

Magnetic anomalies of low amplitude (<100 gammas) are present in the Jurassic magnetic quiet zone of the western Pacific Ocean. These small anomalies are lineated and can be correlated among the Phoenix, Hawaiian and Japanese lineation patterns. Thus, they represent seafloor spreading that recorded some sort of magnetic field phenomena prior to magnetic anomaly M25 at 153 m.y. B.P. The

Steven C. Cande; Roger L. Larson; John L. Labrecque

1978-01-01

387

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

388

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

389

Sulfur geochemistry of Jurassic high-sulfur coals from Egypt  

Microsoft Academic Search

Jurassic high-sulfur coals from the Maghara area in Egypt were analyzed for the abundance and isotopic composition of different forms of sulfur. Analyses indicated that the sulfur occurs in the form of organic, pyrite, and sulfate forms. Pyrite sulfur represents the major fraction, while sulfate sulfur is minor and could be formed during sample preparation for the analyses.The ?34S CDT

Hassan Baioumy

2010-01-01

390

Safety Index of Old Sandstone Arch Bridges Under Ship Impact  

Microsoft Academic Search

In the following article, the examination of an old sandstone arch bridge that is exposed to ship impact is described. The probabilistic calculation to describe the capacity of the bridge is understood to be a part of the overall examination, which also includes other procedures like drilling. 1 PROBLEM DESCRIPTION Sandstone arch bridges are regarded as beautiful constructions. One reason

Manfred Curbach

391

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

392

Bituminous sandstone deposits, Asphalt Ridge, Uinta County, Utah  

Microsoft Academic Search

Asphalt Ridge probably is the second largest bituminous sandstone deposit in NE. Utah's Uinta basin. Discontinuous concentrations of bitumen occur in the Rim Rock Sandstone of the Mesaverde Group of Cretaceous age, in the overlying Uinta Formation of Eocene age and the Duchesne River Formation of Oligocene age. Because the bituminous layers dip SW. -ward under prohibitively deep cover, only

Kayser

1966-01-01

393

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

394

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

Microsoft Academic Search

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

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

2009-01-01

395

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

396

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

Microsoft Academic Search

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

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

1990-01-01

397

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

Microsoft Academic Search

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

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

2010-01-01

398

Geological investigations of pre-late Jurassic terranes in the southernmost Andes  

Microsoft Academic Search

Pre-Late Jurassic terranes of the Patagonian Archipelago were investigated. Their regional stratigraphic and structural characteristics were surveyed. Their significance in the late Paleozoic to early Mesozoic evolution of South America were determined. Pre-Late Jurassic rocks within the archipelago are distributed in two belts. Within the outer belt the Madre de Dios Archipielago was studied in detail. Pre-Late Jurassic rocks of

R. D. Forsythe

1981-01-01

399

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

400

Ammonite faunas and palaeobiogeography of the Himalayan belt during the Jurassic: Initiation of a Late Jurassic austral ammonite fauna  

Microsoft Academic Search

New data obtained in Nepal and Spiti (India) on stratigraphy and Jurassic ammonite faunas form the basis for a new biogeographical interpretation of the peri-Gondwanan faunas. Faunas of the same ages from New Guinea, New Zealand, Antarctica and South America are also considered.From the upper Bathonian up to the Tithonian-Berriasian, six main successive assemblages are distinguished in Nepal and are

Raymond Enay; Elie Cariou

1997-01-01

401

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

402

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

SciTech Connect

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

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

1993-09-01

403

Modeling and analysis of electrical-resistivity soundings made in Jurassic-Triassic basins of the eastern United States  

SciTech Connect

Electrical-resistivity soundings obtained with a Schlumberger field array were used to define the structure, stratigraphy, and depth to basement in the Durham-Wadesboro, Dan River, Richmond, Culpeper, and Newark-Gettysburg Jurassic-Triassic basins in the eastern United States. Geoelectric cross sections constructed from field data processed by computer show that depth to basement rocks and stratigraphic layers differ significantly within and among basins. The cross sections show that resistivities of the intrabasin sedimentary rocks tend to increase with depth, indicating a general decrease in porosity or clay content with depth. Shale layers were found to have 2 to 5 times lower resistivity than sandstone, conglomerate, and limestone. Very massive sedimentary layers have characteristically higher resistivity than thin interbedded layers. Some limestones have resistivities as high as 2200 ohm-meters. Lateral discontinuities, such as faults and facies changes, are inferred where electrical-resistivity soundings were made at close spacing to permit detailed mapping. The sounding data were interpreted by a computer-based model that automatically inverts the sounding curve into layer thicknesses and average layer resistivities. Electrical-resistivity modeling is very useful in understanding subsurface conditions in a variety of geologic environments.

Brown, C.E.

1985-01-01

404

Norphlet Formation (Upper Jurassic) sand erg: depositional model for northeastern De Soto salt basin, eastern Gulf of Mexico  

SciTech Connect

Available well control, seismic reflection geometries, and seismic modeling suggest the interpretation of a Norphlet Formation (Upper Jurassic) sand erg in the northeastern De Soto salt basin. Ranging in thickness from less than 100 ft to nearly 1000 ft, the Norphlet erg encompasses an area of approximately 700 mi/sup 2/. Separated from the major gas accumulation in the Norphlet in the Mobile Bay area by the offshore extension of the Pensacola arch, the Norphlet erg appears to be oriented transverse to the axis of the De Soto salt basin. Seismic signatures for the Smackover carbonate, Norphlet sand, and Louann Salt intervals are investigated using synthetic seismograms generated from six wells in the eastern Gulf of Mexico. General characteristics about the reflection coefficients from the major units in the interval are noted. The reflection coefficient information and synthetic seismograms are used to interpret seismic data on a regional basis. Two-dimensional, vertical-incidence, ray-trace modeling of the seismic data is done to aid the interpretation on a detailed basis. Interpreted Norphlet sandstone thicknesses and Louann Salt structures are combined to support the Norphlet Formation sand erg hypothesis.

Kemmer, D.A.; Reagan, R.L.

1987-05-01

405

Conditioning of formation for sandstone acidizing  

SciTech Connect

This patent describes a method of matrix acidizing a sandstone oil-bearing formation surrounding a wellbore. It comprises: injecting through the wellbore and into the formation a conditioning fluid having solvency for, or in, oil contained within the zone to be treated to miscibly displace the oil outwardly from the wellbore, the conditioning fluid including a solvent selected from the group consisting of carbon dioxide and mixtures of carbon dioxide and another solvent; injecting an aqueous acid preflush solution into the formation to displace the conditioning fluid outwardly from wellbore; injecting an acid solution containing HF into the formation to react with clays in the formation and to displace the acid preflush outwardly from the wellbore; and injecting an afterflush solution into the formation to water wet the formation and to displace the preceding fluids radially outwardly from the wellbore.

Gidley, J.L.

1992-03-31

406

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

407

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

408

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

2002-12-05

409

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.

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

410

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

NASA Astrophysics Data System (ADS)

A Swarm of Late Jurassic alkalic intrusions and geographically limited mainly to the Augusta County in western Virginia has been studied geochemically. These dykes were emplaced along a northwest-southeast cross-strike basement fracture zone during Mesozoic extension. However, not all igneous rocks in Virginia are Jurassic; published K-Ar ages already suggested an Eocene age activity around Monterey, VA (e.g. Fullagar & Bottino 1969). We first systematically sampled and studied these rocks geochemically and used the Ar-Ar dating technique to define a more precise age (around 48Ma) for this youngest volcanic activity East of the Mississippi. The younger igneous bodies have traditionally been interpreted as intrusive bodies representing old plumbing systems of eroded volcanic centers. This hypothesis is based on studies of aphanitic to porphyritic and occasionally vesicular hard rocks from quarries and road cuts. Pyroclastic deposits have mainly been neglected during theses earlier studies. However additional petrographic studies of volcanic sediments are able to shed light not only on the volcanic nature of these pyroclastic rocks but also on eruption mechanisms and magma crust interactions. Our petrographic studies defined that these volcanic sediments contain different clasts of igneous and sedimentary country rocks (sandstones and limestones of different formations), fresh glass shards and crystals of predominantly pyroxene, hornblende and micas. A previously unmapped, massive, m-thick andesitic pyroclastic deposit has been studied in detail to shed light on the formation of theses volcanic sediments. Field relations and observations (e.g.denser rock fragments are enriched in the lower part of the sequence and bedding is largely parallel to the present topography) are consistent with a massive welded ignimbrite. As a result, surface erosion after the eruption must be less significant than previously believed and some rocks are clearly volcanic in nature. Petrogenetically the Jurassic magmas are much more alkalic and particularly K-rich, and thus have all the characteristics as described for delamination magmas by Kay & Kay (1993). This confirms that delamination seems a substantial process during the rift to drift transition. After Jurassic delamination of lithosphere below Virginia hot asthenosphere has been transformed into lithosphere by lithospheritisation. This newly formed lithosphere has later been the mantle source of the Eocene volcanic activity. As a result, the suggested geodynamic model is not only important for the petrology community but also to understand the local geomorphology, seismicity and hot springs.

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

2012-04-01

411

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

412

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

413

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

414

Latest Jurassic-early Cretaceous regressive facies, northeast Africa craton  

SciTech Connect

Nonmarine to paralic detrital deposits accumulated in six large basins between Algeria and the Arabo-Nubian shield during major regression in latest Jurassic and Early Cretaceous time. The Ghadames Sirte (north-central Libya), and Northern (Egypt) basins lay along the cratonic margin of northeastern Africa. The Murzuk, Kufra, and Southern (Egypt) basins lay in the south within the craton. Data for reconstructing distribution, facies, and thickness of relevant sequences are adequate for the three northern basins only. High detrital influx near the end of Jurassic time and in mid-Cretaceous time produced regressive nubian facies composed largely of low-sinuosity stream and fahdelta deposits. In the west and southwest the Ghadames, Murzuk, and Kufra basins were filled with a few hundred meters of detritus after long-continued earlier Mesozoic aggradation. In northern Egypt the regressive sequence succeeded earlier Mesozoic marine sedimentation; in the Sirte and Southern basins correlative deposits accumulated on Precambrian and Variscan terranes after earlier Mesozoic uplift and erosion. Waning of detrital influx into southern Tunisia and adjacent Libya in the west and into Israel in the east initiated an Albian to early Cenomanian transgression of Tethys. By late Cenomanian time it had flooded the entire cratonic margin, and spread southward into the Murzuk and Southern basins, as well as onto the Arabo-Nubian shield. Latest Jurassic-earliest Cretaceous, mid-Cretaceous, and Late Cretaceous transgressions across northeastern Africa recorded in these sequences may reflect worldwide eustatic sea-level rises. In contrast, renewed large supply of detritus during each regression and a comparable subsidence history of intracratonic and marginal basins imply regional tectonic control. 6 figures.

van Houten, F.B.

1980-06-01

415

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

416

Reconstruction of the Upper Jurassic Morrison Formation extinct ecosystem—a synthesis  

Microsoft Academic Search

A synthesis of recent and previous studies of the Morrison Formation and related beds, in the context of a conceptual climatic\\/hydrologic framework, permits reconstruction of the Late Jurassic dinosaurian ecosystem throughout the Western Interior of the United States and Canada. Climate models and geologic evidence indicate that a dry climate persisted in the Western Interior during the Late Jurassic. Early

Christine E. Turner; Fred Peterson

2004-01-01

417

Cold episodes inside Jurassic times: is the carbonate deposition engine controlling atmospheric CO2?  

Microsoft Academic Search

The calculated history of Phanerozoic CO2 suggests a rather constantly warm Mesozoic (Berner and Kothavala, 2001). This result is in disagreement with recent findings suggesting the occurrence of short (several 105 years) glacial episodes during the Jurassic, particularly at the Middle-Late Jurassic transition (Dromart et al., 2003). This climatic event is linked to perturbations in the carbonate production, with a

Y. Godderis; Y. Donnadieu; G. Dromart; R. T. Pierrehumbert

2006-01-01

418

A new insect trace fossil in Jurassic wood from Patagonia, Argentina  

Microsoft Academic Search

A new trace fossil assigned to insect activity in wood is described from the Jurassic Petrified Forest of Jaramillo in Santa Cruz Province (Argentina). Dekosichnus meniscatus n. ichnogen. n. ichnosp. is the second known Jurassic trace occurring in permineralized wood. The boring system is composed of longitudinal tunnels connected by tangential tunnels. The system is connected to the exterior by

Jorge F. Genise; Patricia L. Hazeldine

1995-01-01

419

Hettangian (Early Jurassic) plant fossils from Puale Bay (Peninsular terrane, Alaska)  

Microsoft Academic Search

Middle Hettangian (Early Jurassic) plant macrofossils from the Kamishak Formation at Puale Bay, Alaska occur mainly as leaves and leafy shoots found together with ammonites that allow precise biostratigraphic age assignment. This new locality is the first in the Jurassic of Alaska where the plant material shows preserved cuticle. Four species of three genera are identified representing three different gymnosperm

Maria Barbacka; József Pálfy; Paul L. Smith

2006-01-01

420

Jurassic foraminifera from the Queen Charlotte Islands, British Columbia, Canada: biostratigraphy, paleoenvironments and paleogeographic implications  

Microsoft Academic Search

Lower and Middle Jurassic (Sinemurian to Callovian) foraminifera were examined from 66 localities of the Queen Charlotte Islands, British Columbia, Canada. Over 200 species of well preserved benthic calcareous and agglutinated taxa belonging to 50 genera were identified. Foraminifera from the Lower Jurassic are represented by an abundant and diverse, Tethyan-derived calcareous assemblage, with Boreally derived agglutinated taxa becoming gradually

N. Kottachchi; C. J. Schröder-Adams; J. W. Haggart; H. W. Tipper

2002-01-01

421

Organic facies in Cretaceous and Jurassic hydrocarbon source rocks, Southern Indus basin, Pakistan  

Microsoft Academic Search

A detailed organic petrographic study of the geologic section penetrated by the Sann #1 well in the Southern Indus basin (Kirthar Trough) of Pakistan permits definition of organic facies and oil-generation potential of Cretaceous and Jurassic source rocks. The well encountered Eocene through Jurassic rocks; however, only closely spaced samples of fine-grained rocks from the Cretaceous Goru, Sembar, and the

C. R Robison; M. A Smith; R. A Royle

1999-01-01

422

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

423

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

424

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

425

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

426

Basin-wide architecture of sandstone reservoirs in the Fort Union Formation, Wind River basin, Wyoming  

Microsoft Academic Search

Architecture of hydrocarbon-bearing sandstone reservoirs of the Paleocene Fort Union Formation in the Wind River basin, Wyoming, was studied using lithofacies, grain size, bounding surfaces, sedimentary structures, internal organization, and geometry. Two principal groups of reservoirs, both erosionally based and fining upward, consist of either conglomeratic sandstone or sandstone lithofacies. Two types of architecture were recognized in conglomeratic sandstone reservoirs:

R. M. Flores; C. W. Keighin; W. R. Keefer

1991-01-01

427

Direct chemical evidence for eumelanin pigment from the Jurassic period  

PubMed Central

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

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

2012-01-01

428

Tanzania wildcats to evaluate Jurassic Mandawa salt basin  

SciTech Connect

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

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

1996-10-07

429

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

2012-05-21

430

First occurrence of Brachiosaurus (Dinosauria: Sauropoda) from Brachiosaurus (Dinosauria: Sauropoda) from Brachiosaurus the Upper Jurassic Morrison Formation of Oklahoma  

Microsoft Academic Search

The giant sauropod Brachiosaurus is one of the rarest sauropods from the Upper Jurassic of North America. The Brachiosaurus is one of the rarest sauropods from the Upper Jurassic of North America. The Brachiosaurus genus has previously been reported from Colorado, Utah, and Wyoming. OMNH 01138 is a sauropod metacarpal of unusual proportions from the Upper Jurassic Morrison Formation of

MATTHEW F. BONNAN; MATHEW J. WEDEL

431

Sedimentary — diagenetic interpretation and reservoir characteristics of the Middle Jurassic (Araej Formation) in the southern Arabian Gulf  

Microsoft Academic Search

Oil and gas condensates discovered so far in the Middle Jurassic Araej Formation occur in several structures in western and central offshore Abu Dhabi and Qatar. The source for the oil is thought to have migrated updip primarily from the Hanifa\\/Diyab Formation (Upper Jurassic), whereas the source of the gas condensate is believed to be from Middle Triassic-Lower Jurassic formations.

A. S. Alsharhan; G. L. Whittle

1995-01-01

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 Cinku

2010-01-01

433

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

434

Stress-Strain and Fracture Properties of Nugget Sandstone.  

National Technical Information Service (NTIS)

Experimental measurements of the stress-strain and fracture properties of laboratory specimens of Nugget sandstone are described. A servo-controlled triaxial compression testing apparatus was employed which permitted simultaneous control of the lateral an...

W. S. Brown S. R. Swanson

1971-01-01

435

NMR spectroscopic examination of shocked sandstone from Meteor Crater, Arizona.  

National Technical Information Service (NTIS)

Solid state silicon-29 nuclear magnetic resonance (NMR) spectroscopy has been used to characterize the formation of high pressure silica polymorphs and amorphous material associated with the shocked Coconino Sandstone from Meteor Crater, Arizona. Five sam...

R. T. Cygan M. B. Boslough R. J. Kirkpatrick

1993-01-01

436

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

SciTech Connect

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

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

1990-05-01

437

The sliding characteristics of sandstone on quartz fault-gouge  

Microsoft Academic Search

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

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

1975-01-01

438

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

439

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.

440

Salt and ice crystallisation in porous sandstones  

NASA Astrophysics Data System (ADS)

Salt and ice crystallisation in the pore spaces causes major physical damage to natural building stones. The damaging effect of these processes can be traced back to physically induced stress inside of the rock while crystallizing. The increasing scientific research done during the past century has shown that there are numerous parameters that have an influence on the weathering resulting from these processes. However, the working mechanisms of the stress development within the rock and its material dependency are still subject to discussion. This article gives an overview of salt and ice weathering. Additionally, laboratory results of various sandstones examined are presented. Salt crystallisation tests and freeze/thaw tests were done to obtain information about how crystallisation weathering depends on material characteristics such as pore space, water transportation, and mechanical features. Simultaneous measuring of the length alternating during the salt and ice crystallisation has revealed detailed information on the development of crystal in the pore spaces as well as the development of stress. These findings can help to understand the damaging mechanisms.

Ruedrich, Joerg; Siegesmund, Siegfried

2007-03-01

441

New early Jurassic decapod crustacean from Patagonia (Chubut province), Argentina  

Microsoft Academic Search

A well-preserved decapod specimen was found in early Toarcian deposits cropping out on the western slope of Meseta Catreleo,\\u000a central Chubut province, Argentina. It is a nearly complete exoskeleton preserved in lateral view, slightly crushed, in fine-grained\\u000a sandstones. The skeleton is mostly articulated, though some pieces are disarticulated or missing. Taphonomic features indicate\\u000a a relatively rapid burial after death, with

M. A. PaganiS; S. E. Damborenea; M. O. Manceñido; S. M. Ferrrari

2011-01-01

442

Triassic and Jurassic rocks at Currie, Nevada Preliminary paleontologic evidence  

Microsoft Academic Search

A sequence of continental rocks overlies the Lower Triassic Thaynes Formation in a poorly exposed syncline near Currie in northeastern NV. The authors recognize four lithostratigraphic units above the Thaynes near Currie and provide new paleontologic data. In ascending order, unit 1 (120 ft) consists of reddish-brown, very fine grained sandstone. Unit 2 (50 ft) consists of light-gray, trough cross-stratified,

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

1993-01-01

443

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

444

Amphibious flies and paedomorphism in the Jurassic period.  

PubMed

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

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

2013-02-20

445

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

446

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

USGS Publications Warehouse

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

Bunnell, Joseph E.; Garcia, Linda V.

2008-01-01

447

Optical methods for determining the porosity and permeability of sandstones  

NASA Astrophysics Data System (ADS)

An optical method has been devised for determining the permeability (single-phase) and porosity, as well as the grain size of sandstones, utilizing the principle of total internal reflection (TIR) of light. TIR occurs due to the difference of refractive indices (n) between two media; in this case, the quartz grains (n ? 1.53) which are abundant in sandstones and a liquid which saturated all the sandstone samples, Mono-Isopropyl Biphenyl (MIB, n = 1.57). This was achieved by placing 'thick' rock sections (as opposed to thin sections used in optical microscopy), 5 mm thick and saturated with MIB, between an infrared source-detector system and measuring the resulting light output. The light output was due to the scattering and refraction of light through the transparent quartz grains, and by TIR of light from the boundaries of the grains, through the pore spaces of the sandstone sample. The purpose of this experiment was to establish a relationship between the light output and the internal pore structure of the sandstone samples, using one fixed wavelength (i.e. 1?m) as a platform for future studies utilizing many different wavelengths in the infrared range. For sandstones of moderate porosity and moderate to high permeability, a good correlation was observed between the grain size distribution and light output while the correlation with porosity and permeability was dominated by the amount of quartz and their size in the samples. Predicting the internal structure of sandstones by this method could provide a useful and quick method in laboratory sampling of some porous materials as well as a promising approach in the development of a well logging device.

Zaman, Shah Mohammed

1997-09-01

448

Middle to Late Jurassic Tectonic Evolution of the Klamath Mountains, California-Oregon  

NASA Astrophysics Data System (ADS)

The geochronology, stratigraphy, and spatial relationships of Middle and Late Jurassic terranes of the Klamath Mountains strongly suggest that they were formed in a single west-facing magmatic arc built upon older accreted terranes. A Middle Jurassic arc complex is represented by the volcanic rocks of the western Hayfork terrane and consanguineous dioritic to peridotitic plutons. New U/Pb zircon dates indicate that the Middle Jurassic plutonic belt was active from 159 to 174 Ma and is much more extensive than previously thought. This plutonic belt became inactive just as the 157 Ma Josephine ophiolite, which lies west and structurally below the Middle Jurassic arc, was generated. Late Jurassic volcanic and plutonic arc rocks (Rogue Formation and Chetco intrusive complex) lie outboard and structurally beneath the Josephine ophiolite; U/Pb and K/Ar age data indicate that this arc complex is coeval with the Josephine ophiolite. Both the Late Jurassic arc complex and the Josephine ophiolite are overlain by the "Galice Formation," a Late Jurassic flysch sequence, and are intruded by 150 Ma dikes and sills. The following tectonic model is presented that accounts for the age and distribution of these terranes: a Middle Jurassic arc built on older accreted terranes undergoes rifting at 160 Ma, resulting in formation of a remnant arc/back-arc basin/island arc triad. This system collapsed during the Late Jurassic Nevadan Orogeny (150 Ma) and was strongly deformed and stacked into a series of east-dipping thrust sheets. Arc magmatism was active both before and after the Nevadan Orogeny, but virtually ceased at 140 Ma.

Harper, Gregory D.; Wright, James E.

1984-12-01

449

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

PubMed Central

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

Kaptchuk, Ted J.

2011-01-01

450

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

451

Jurassic salt tectonism within Mt. Enterprise fault system, Rusk County, Texas  

SciTech Connect

A synthesis of seismic, bore-hole, and gravity data in southeastern Rusk County, Texas, indicates that faulting within the Mt. Enterprise fault system was the result of Jurassic salt tectonism. Faults were developed in response to salt movement and subsequent collapse of the overlying section into areas of salt withdrawal, resulting in the formation of a graben containing no Louann Salt. An abnormally thick Bossier Formation within the graben indicates a Late Jurassic age for significant structural deformation within the fault zone. The potential exists for numerous untested traps within the Jurassic section associated with salt-generated structures along the Mt. Enterprise fault system.

Ferguson, J.D.

1985-02-01

452

Inclination variation in the Late Jurassic to Eocene red beds from southeast Asia: lithological to locality scale approach  

NASA Astrophysics Data System (ADS)

Shallow palaeomagnetic inclinations have been frequently reported from the red beds of central and southeast Asia. To trace the origin of this phenomenon, inclination variation in southeast Asia is examined on lithological to locality scale. Lithological aspect of this variation has been studied using the Early Cretaceous Bailong and Cangxi formations of the Bazhong area (32.1°N, 106.7°E), the northern Sichuan Basin. Samples from 36 sites, consisting 18 pairs of successive sandstones and mudstones layers, were collected for this purpose from a synclinal structure. Stepwise thermal demagnetization of most samples revealed the presence of stable characteristic remanent magnetization, which is generally unblocked by 680 °C. Positive fold and reversal tests suggest a primary origin for this component, yielding the Early Cretaceous palaeomagnetic direction of declination/inclination = 20.9°/26.5° (ks= 37.2, ?95= 4.4°, N= 30). 10 pairs of sandstone and mudstone layers show almost identical inclinations (Isandstones= 23.3°± 3.7° and Imudstones= 24.7°± 2.4°), but 27° shallower than that expected from the Eurasian apparent polar wander paths (APWPs), indicating that no lithological variation in inclination has occurred. Location-wise variation in inclination shallowing is examined through palaeomagnetic data from Late Jurassic to Eocene red beds distributed around southeast Asia. Based on these investigations, no inclination shallowing is observed in the eastern part of the South China Block (SCB), whereas large degree of shallowing is observed in the Sichuan and Xining-Ninhe basins. Variation in inclination shallowing from one sedimentary basin to another could probably be caused by changes in the depositional environment. The eastern part of the SCB, where no inclination shallowing have been observed, is characterized by Basin and Range type tectono-geological setting. In contrast, the foreland basins are bounded to the north by east-west striking high altitude orogenic belt. Swift development of these basins as a result of flexural subsidence is the most likely reason for inclination shallowing.

Sato, Shun; Yang, Zhenyu; Tong, Yobo; Fujihara, Makoto; Zaman, Haider; Yokoyama, Masahiko; Kitada, Kazuya; Otofuji, Yo-Ichiro

2011-08-01

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

Paleogeographic and Tectonic Implications of Quartzose Sandstones of Barbados  

NASA Astrophysics Data System (ADS)

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

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

1986-10-01

455

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

SciTech Connect

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

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

2004-11-15

456

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