Note: This page contains sample records for the topic heterogeneous geological formations from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Macro-scale constitutive relationships for CO2 migration in heterogeneous geological formations  

NASA Astrophysics Data System (ADS)

Numerical models have been developed and applied to migration of geological stored carbon dioxide for site performance and risk assessment studies at the reservoir scale. However, due to the restriction in computational time and resources, reservoir scale models have limitations in accounting for the multi-scale heterogeneities. In order to address the heterogeneity issues, appropriate upscaling methods are needed. In this study, we present macro-scale capillary pressure - relative permeability - saturation relationships for grid-block properties used in the full-scale modeling. We develop a macroscopic percolation model for the upscaling procedures. The macro-scale constitutive relationships are obtained through simulation procedures of CO2 displacing brine in a porous domain with spatially correlated random permeability fields. Sensitivity of the derived constitutive relationships to the statistical parameters representing the local heterogeneity is shown. Comparison of the percolation-based method to other approaches is demonstrated.

Yang, Z.; Niemi, A.; Tian, L.; Fagerlund, F.; Illangasekare, T. H.

2012-04-01

2

Eulerian-Lagrangian approach for modeling of flow and transport in heterogeneous geological formations  

Microsoft Academic Search

This paper presents a new Eulerian-Lagrangian method for modeling flow and transport of passive solutes in heterogeneous porous formations. The physically plausible random velocity fields are generated by a geostatistical based model. The ability of the method to correctly reproduce the velocity field statistics and to satisfy mass balance is tested and demonstrated for the case of two-dimensional flow. The

Alberto Bellin; Yoram Rubin; Andrea Rinaldo

1994-01-01

3

Formation evaluation: Geological procedures  

SciTech Connect

This volume goes beyond a discussion of petroleum geology and the techniques of hydrocarbon (oil and gas) logging as a reservoir evaluation tool. It provides the logging geologist with a review of geological techniques and classification systems that will ensure the maximum development of communicable geological information. Contents include: 1. Introduction--cuttings recovery, cutting sampling, core sampling, rock classification; 2. Detrital rocks--classification, description; 3. Carbonate rocks--classification, description; 4. Chemical rocks-introduction, siliceous rocks, ferruginous rocks, aluminous rocks, phosphatic rocks, aluminous rocks, carbonaceous rocks; 5. Igneous and metamorpbic rocks; Appendix; References and Index.

Whittaker, A.

1985-01-01

4

Geologic Puzzles: Morrison Formation  

NSDL National Science Digital Library

Images of faulted strata, tilted turbidites, and beach rocks bring the field into the classroom, giving students practice in doing what geoscientists do. These images are examples of geologic puzzles.

Macdonald, Heather

5

Anomalous transport in weakly heterogeneous geological porous media  

NASA Astrophysics Data System (ADS)

Anomalous transport is found to be ubiquitous in complex geological formations and it has a paramount impact on petroleum engineering and groundwater sciences. This process can be well described by the continuous time random walk (CTRW) model, in which the probability density function w(t) of a particle's transition time t follows a power law for large t: w(t)˜t-1-? (0geological porous media with weakly heterogeneous microstructures.

Wang, Yan

2013-03-01

6

Two Dimensional Stochastic Model of a Heterogeneous Geologic System.  

National Technical Information Service (NTIS)

Models based on probabilistic laws are increasingly being employed to simulate heterogeneous geologic systems. One such model, the 'Poisson lines' model, is discussed. This is a two dimensional stochastic model with Markovian properties which is generated...

M. J. Lippmann

1973-01-01

7

Method of fracturing a geological formation  

DOEpatents

An improved method of fracturing a geological formation surrounding a well bore is disclosed. A relatively small explosive charge is emplaced in a well bore and the bore is subsequently hydraulically pressurized to a pressure less than the formation breakdown pressure and preferably greater than the fracture propagation pressure of the formation. The charge is denoted while the bore is so pressurized, resulting in the formation of multiple fractures in the surrounding formation with little or no accompanying formation damage. Subsequent hydraulic pressurization can be used to propagate and extend the fractures in a conventional manner. The method is useful for stimulating production of oil, gas and possibly water from suitable geologic formations.

Johnson, James O. (2679-B Walnut, Los Alamos, NM 87544)

1990-01-01

8

River-Aquifer Interactions, Geologic Heterogeneity, and River Management  

NASA Astrophysics Data System (ADS)

Managing rivers and their underlying aquifers for minimum flows, riparian habitat or aquifer recharge requires an understanding of the spatial patterns and temporal dynamics of river-aquifer exchange. Results are presented from investigations of the effects of geologic heterogeneity on river-aquifer exchange, minimum river flows and water availability in the riparian corridor for a typical alluvial fan system in the western USA. River-aquifer interactions were simulated on a regional-scale (~50km) and for a river reach (~2000m) using numerical codes for saturated and variably saturated flow. Geologic heterogeneity of the alluvial fan system was characterized with a geostatistical approach, based on transition probabilities and Markov Chains. Different hydrofacies models for a 50 km segment and a 2 km reach were created from sequential indicator simulations. Variably saturated flow between the river and the deep regional water table were explicitly simulated in both models. Groundwater levels, river flows, sediment saturation and temperature data were used to calibrate the models. The regional simulations showed that different spatial arrangements of hydrofacies have significant effects on minimum river flows with implications for salmon migration. Although total annual seepage volumes were relatively insensitive to geologic heterogeneity spatial and temporal variability of seepage was large between the different heterogeneous models. Local reconnections developed seasonally in some models and the period with sufficient flows for salmon fall-migration varied by up to 13 days between the models. The reach-scale simulations demonstrated that perched zones, which form between the river and the regional water table, can be important in supporting river base flows and riparian vegetation. Connected pathways between the river channel and the riparian corridor, which could be characterized with the temperature data, may sustain phreatophytes even when the regional water table is far below the river channel. These results elucidate some important effects of geologic heterogeneity on river-aquifer interactions, which could be crucial for the management of alluvial river systems.

Fleckenstein, J. H.; Niswonger, R. G.; Fogg, G. E.

2005-12-01

9

Geological pattern formation by growth and dissolution in aqueous systems  

Microsoft Academic Search

Although many geological processes take place on time scales that are very long compared with the human experience, essentially all geological processes, fast or slow, are far from equilibrium processes. Surprisingly often, geological processes lead to the formation of quite simple and distinctive patterns, which hint at an underlying simplicity in many complex geological systems.. The ability to predict the

Paul Meakin; B. Jamtveit

2009-01-01

10

Petroleum column heterogeneity as a geological tool: Origin and significance of tar mats  

SciTech Connect

Compositional heterogeneity in liquid petroleum columns can be related to variation in (1) the maturities and facies of the source rocks feeding the field, (2) the complexity of the carrier beds acting as filling conduits, (3) the controls of physical mixing, diffusion and in-reservoir adsorption on the homogenization of heterogeneities inherited by the field during its filling, and (4) alteration of petroleum composition post trapping. The absence of convection in most liquid petroleum columns plus the inability of diffusive mixing in petroleum columns to homogenize large scale (1 km) heterogeneity even on a geological time scale, allows the petroleum geologist/geochemist to use these heterogeneities as geological tools. Tar mats, or viscous oil barriers, are commonly found in paraffinic oil reservoirs (as, e.g., in the North Sea Oseberg and Ula fields, and in Prudoe Bay field, Alaska). They commonly represent zones of from 1-25 m of asphaltene-rich oil (typically around 50% asphaltenes) sometimes at oil/water contacts with sharp compositional contrast and contact with the rest of the oil column. They are significant in that they represent potential flow barriers, often petroleum columns with tar mats have production and safety problems associated with deasphalting during production. Although there has been much debate on their origin, most field evidence is circumstantial. The authors present a new model of tar-mat formation based on physical-chemical considerations and an improved chemical structural model of asphaltenes, and they show with case histories how this information can be used to aid the geologist in geologically interpreting reservoir geochemical information relating to field-charging processes.

Wilhelms, A. (Univ. of Oslo (Norway)); Larter, S. (Univ. of Newcastle, Newcastle upon Tyne (United Kingdom))

1991-08-01

11

Effect of strong heterogeneity on the onset of convection in a porous medium: Importance of spatial dimensionality and geologic controls  

Microsoft Academic Search

The effect of strong heterogeneity on the onset of convection induced by a vertical density gradient in a saturated heterogeneous porous medium governed by Darcy's law is investigated. A computer package has been developed to study the applicability of an average Rayleigh number as a criterion for the onset of convection in strongly heterogeneous geologic media. The heterogeneous geologic media

Craig T. Simmons; A. V. Kuznetsov; D. A. Nield

2010-01-01

12

Geologic Study of the Coso Formation  

SciTech Connect

There have been great advances in the last 20 years in understanding the volcanic, structural, geophysical, and petrologic development of the Coso Range and Coso geothermal field. These studies have provided a wealth of knowledge concerning the geology of the area, including general structural characteristics and kinematic history. One element missing from this dataset was an understanding of the sedimentology and stratigraphy of well-exposed Cenozoic sedimentary strata - the Coso Formation. A detailed sedimentation and tectonics study of the Coso Formation was undertaken to provide a more complete picture of the development of the Basin and Range province in this area. Detailed mapping and depositional analysis distinguishes separate northern and southern depocenters, each with its own accommodation and depositional history. While strata in both depocenters is disrupted by faults, these faults show modest displacement, and the intensity and magnitude of faulting does no t record significant extension. For this reason, the extension between the Sierran and Coso blocks is interpreted as minor in comparison to range bounding faults in adjacent areas of the Basin and Range.

D. L. Kamola; J. D. Walker

1999-12-01

13

Continuum-scale convective mixing in geological CO2 sequestration in anisotropic and heterogeneous saline aquifers  

NASA Astrophysics Data System (ADS)

Deep saline aquifers are important geological formations for CO2 sequestration. It has been known that dissolution of CO2 increases brine density, which results in downward density-driven convection and consequently greatly enhances CO2 sequestration. In this study, a continuum-scale lattice Boltzmann model is used to investigate convective mixing of CO2 in saline aquifers. It is found that increasing permeability in either the vertical or horizontal direction accelerates the development of convective mixing. In a heterogeneous aquifer, increasing heterogeneity hampers the onset of convective mixing, because the heterogeneous permeability field results in a large portion of low-velocity region which reduces the instability of the system. The critical time for the onset of instability depends mainly on the coefficient of variation (COV) of the permeability field, and is insensitive to the correlation length. This implies that within the scale of critical time, mass transport is dominated by diffusion, and thus depends mainly on fine-scale heterogeneity controlled by COV. We derived an empirical formula for estimating the critical time, which leads to good estimates for all combinations of COV and correlation length. Fingering, channeling, and dispersion are the three mechanisms for mass transport. In dispersion, dissolved mass is approximately proportional to the square root of time, while in fingering and channeling it is approximately proportional to time. Mass transport by channeling depends significantly on permeability structure, while by fingering it is controlled by gravitational instability. It is also found that larger volumes of CO2 can be stored in heterogeneous aquifers because of higher mass dissolution rates.

Chen, Cheng; Zeng, Lingzao; Shi, Liangsheng

2013-03-01

14

Constructing Hydraulic Barriers in Deep Geologic Formations  

SciTech Connect

Many construction methods have been developed to create hydraulic barriers to depths of 30 to 50 meters, but few have been proposed for depths on the order of 500 meters. For these deep hydraulic barriers, most methods are potentially feasible for soil but not for hard rock. In the course of researching methods of isolating large subterranean blocks of oil shale, the authors have developed a wax thermal permeation method for constructing hydraulic barriers in rock to depths of over 500 meters in competent or even fractured rock as well as soil. The technology is similar to freeze wall methods, but produces a permanent barrier; and is potentially applicable in both dry and water saturated formations. Like freeze wall barriers, the wax thermal permeation method utilizes a large number of vertical or horizontal boreholes around the perimeter to be contained. However, instead of cooling the boreholes, they are heated. After heating these boreholes, a specially formulated molten wax based grout is pumped into the boreholes where it seals fractures and also permeates radially outward to form a series of columns of wax-impregnated rock. Rows of overlapping columns can then form a durable hydraulic barrier. These barriers can also be angled above a geologic repository to help prevent influx of water due to atypical rainfall events. Applications of the technique to constructing containment structures around existing shallow waste burial sites and water shutoff for mining are also described. (authors)

Carter, E.E.; Carter, P.E. [Technologies Co, Texas (United States); Cooper, D.C. [Ph.D. Idaho National Laboratory, Idaho Falls, ID (United States)

2008-07-01

15

Sparse Geologic Dictionaries for Identification of Subsurface Heterogeneity: A New Inverse Modeling Perspective  

NASA Astrophysics Data System (ADS)

Identification of heterogeneous hydraulic rock properties from flow data presents a challenging problem in modeling and prediction of fluid flow displacement in subsurface environments. Inference of these properties from limited dynamic flow measurements typically leads to a severely underdetermined nonlinear inverse problem that can have many non-unique solutions. The problem is usually regularized by incorporating implicit or explicit prior information in the search for an acceptable solution. Reducing the number of unknown parameters and/or constraining the solution space by imposing an appropriate structural assumption on the solution are common approaches for stabilizing the solution of ill-posed inverse problems. In geosciences inverse problems, a valid structural assumption must be supported by the physics of the problem, by the available information about the geologic history of the formation, and by other sources of information such as outcrop, well logs and seismic data. In this paper, we present a geologically-motivated regularization approach for representation and estimation of subsurface hydraulic properties. The approach is based on construction of a field-specific diverse geologic dictionary from a collection of prior model realizations. The main property of the constructed dictionary is that it can sparsely represent any individual realization in the collection of prior models; that is, only a small subset of the geologic dictionary elements is needed to accurately approximate each individual model in the prior library. Inspired by recent development in sparse signal processing, we formulate the inverse modeling as a sparse reconstruction problem and find its solution by searching for a sparse combination of model elements in the geologic dictionary that can reproduce the dynamic flow data. To identify these relevant components in the large geologic dictionary and to estimate their contribution (weight), we implement an efficient iteratively reweighted least-squares reconstruction algorithm that minimizes a data misfit objective function augmented with a sparsity regularization term over the dictionary. We illustrate the effectiveness and suitability of this new inversion approach and compare it with alternative prior-based methods using a series of numerical experiments in two-phase fluid flow problems.

Jafarpour, B.; M. Khaninezhad, M. R.

2011-12-01

16

A Laboratory Study of Heterogeneity and Scaling in Geologic Media  

NASA Astrophysics Data System (ADS)

In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. For sedimentary materials the length scales are: the pore scale (irregularities in grain surface roughness and cementation), the scale of grain packing faults (and the resulting correlated porosity structures), the scale dominated by sorting or winnowing due to depositional processes, and the scale of geomorphology at the time of deposition. We are studying the heterogeneity and anisotropy in geometry, permeability, and geophysical response from the pore (microscopic), laboratory (mesoscopic), and backyard field (macroscopic) scales. In turn these data are being described and synthesized for development of mathematical models. Eventually, we will perform parameter studies to explore these models in the context of transport in the vadose and saturated zones. We have developed a multi-probe physical properties scanner which allows for the mapping of geophysical properties on a slabbed sample or core. This device allows for detailed study of heterogeneity at those length scales most difficult to quantify using standard field and laboratory practices. The measurement head consists of a variety of probes designed to make local measurements of various properties, including: gas permeability, acoustic velocities (compressional and shear), complex electrical impedance (4 electrode, wide frequency coverage), and ultrasonic reflection (ultrasonic impedance and permeability). We can thus routinely generate detailed geophysical maps of a particular sample. We are testing and modifying these probes as necessary for use on soil samples. As a baseline study we have been characterizing the heterogeneity of a bench-size Berea sandstone block. Berea Sandstone has long been regarded as a laboratory standard in rock properties studies, owing to its uniformity and ``typical'' physical properties. We find that both permeability and velocity exhibit complex heterogeneity at the centimeter scale. While some correlation with the outcropping of the bedding is apparent, much of the heterogeneity is not clearly associated with visual features. For the study of soil heterogeneity at a wide range of scales, we are focusing on a local glacial deposit. This deposit is a glacial kame terrace of fluvial origin with multi-scale sedimentary structures comprised of unconsolidated sands, clays, and gravels. There are also many joints and faults in the unconsolidated sediments, allowing study of these as potential fluid flow conduits or barriers. We have obtained undisturbed soil samples from this site, allowing detailed laboratory study using similar methods to those described for the sandstone block.

Brown, S.; Boitnott, G.; Bussod, G.; Hagan, P.

2004-05-01

17

A Laboratory Study of Heterogeneity and Scaling in Geologic Media  

NASA Astrophysics Data System (ADS)

In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. For sedimentary materials the length scales are: the pore scale (irregularities in grain surface roughness and cementation), the scale of grain packing faults (and the resulting correlated porosity structures), the scale dominated by sorting or winnowing due to depositional processes, and the scale of geomorphology at the time of deposition. We are studying the heterogeneity and anisotropy in geometry, permeability, and geophysical response from the pore (microscopic), laboratory (mesoscopic), and backyard field (macroscopic) scales. In turn these data are being described and synthesized for development of mathematical models. Eventually, we will perform parameter studies to explore these models in the context of transport in the vadose and saturated zones. We have developed a multi-probe physical properties scanner which allows for the mapping of geophysical properties on a slabbed sample or core. This device allows for detailed study of heterogeneity at those length scales most difficult to quantify using standard field and laboratory practices. The measurement head consists of a variety of probes designed to make local measurements of various properties, including: gas permeability, acoustic velocities (compressional and shear), complex electrical impedance (4 electrode, wide frequency coverage), and ultrasonic reflection (ultrasonic impedance and permeability). We can thus routinely generate detailed geophysical maps of a particular sample. With the exception of the acoustic velocity, we are testing and modifying these probes as necessary for use on soil samples. As a baseline study we have been characterizing the heterogeneity of a bench-size Berea sandstone block. Berea Sandstone has long been regarded as a laboratory standard in rock properties studies, owing to its uniformity and ``typical'' physical properties. We find that both permeability and velocity exhibit complex heterogeneity at the centimeter scale. While some correlation with the outcropping of the bedding is apparent, much of the heterogeneity is not clearly associated with visual features. For the study of soil heterogeneity at a wide range of scales, we are focusing on a local glacial deposit. This deposit is a glacial kame terrace of fluvial origin with multi-scale sedimentary structures comprised of unconsolidated sands, clays, and gravels. There are also many joints and faults in the unconsolidated sediments, allowing study of these as potential fluid flow conduits or barriers. We have obtained undisturbed soil samples from this site, allowing detailed laboratory study using similar methods to those described for the sandstone block.

Brown, S.; Boitnott, G.; Smith, M.

2003-12-01

18

Scales of geological heterogeneity of a deep-water sand giant oil field  

Microsoft Academic Search

To understand the levels of accuracy that can be placed upon different scales of reservoir description, turbidite intervals in part of the giant Wilmington oil field, California, have been numerically described at four scales of heterogeneity. The degree of accuracy of the description, in terms of real geologic variability, is found to diminish with increasing scale. At the microscale (grains

R. M. Slatt; S. Phillips; J. M. Boak; M. B. Lagoe

1990-01-01

19

Applying Seismic Methods to National Security Problems: Matched Field Processing With Geological Heterogeneity  

Microsoft Academic Search

Seismic imaging and tracking methods have intelligence and monitoring applications. Current systems, however, do not adequately calibrate or model the unknown geological heterogeneity. Current systems are also not designed for rapid data acquisition and analysis in the field. This project seeks to build the core technological capabilities coupled with innovative deployment, processing, and analysis methodologies to allow seismic methods to

S Myers; S Larsen; J Wagoner; B Henderer; D McCallen; J Trebes; P Harben; D Harris

2003-01-01

20

Petroleum geology of the Vicksburg Formation, Texas  

SciTech Connect

The Late Oligocene Vicksburg Formation of the Texas Gulf Coastal Plain lies within the Tertiary depositional wedge between the Upper Eocene Jackson Group and the Upper Oligocene Frio-Catahoula Formations. Across the state of Texas there are a total of 351 fields producing from the Vicksburg Formation; as of 1 January 1982, these fields had produced cumulative totals of 73.5 million barrels of oil, 4 million barrels of condensate, and 274 billion cubic feet of gas. In the Rio Grande Embayment of South Texas, the Vicksburg Formation has long been recognized as a prolific petroleum producer from shelf-edge delta sand reservoirs. In the Houston Embayment of the eastern Texas coastal plain, the Vicksburg producing sands were deposited in a deltaic systems tract positioned on the relict Jackson shelf platform. Regional depositional systems analysis of the Central Texas Vicksburg Formation has demonstrated that this unit is dominated by a belt composed of a strike-oriented paralic sand complex. The depositional environments responsible for these interrelated coastal sands include delta flanks and their associated shorezone, strand plain, and barrier systems. These paralic sands are the lateral equivalent of the Vicksburg deltaic system in the Houston Embayment and of the extensively growth-faulted deltas within the Rio Grande Embayment. Across the Texas coast, the fields producing from the Vicksburg are associated with the Vicksburg Growth Fault Zone. The reservoirs are most commonly found in the uppermost sands of the deltaic sections; the porosity is usually secondary, controlled by diagenesis. Most of the fields have anticlinal closure or a structural-stratigraphic combination trapping situation.

Coleman, J.; Galloway, W.E. (Univ. of Texas, Austin (USA))

1990-09-01

21

The Suitable Geological Formations for Spent Fuel Disposal in Romania  

SciTech Connect

Using the experience in the field of advanced countries and formerly Romanian program data, ANDRAD, the agency responsible for the disposal of radioactive wastes, started the program for spent fuel disposal in deep geological formations with a documentary analysis at the national scale. The potential geological formations properly characterized elsewhere in the world: salt, clay, volcanic tuff, granite and crystalline rocks,. are all present in Romania. Using general or specific selection criteria, we presently consider the following two areas for candidate geological formations: 1. Clay formations in two areas in the western part of Romania: (1) The Pannonian basin Socodor - Zarand, where the clay formation is 3000 m thick, with many bentonitic strata and undisturbed structure, and (2) The Eocene Red Clay on the Somes River, extending 1200 m below the surface. They both need a large investigation program in order to establish and select the required homogeneous, dry and undisturbed zones at a suitable depth. 2. Old platform green schist formations, low metamorphosed, quartz and feldspar rich rocks, in the Central Dobrogea structural unit, not far from Cernavoda NPP (30 km average distance), 3000 m thick and including many homogeneous, fine granular, undisturbed, up to 300 m thick layers. (authors)

Marunteanu, C. [Bucharest Univ. (Romania); Ionita, G. [ANDRAD, Bucharest (Romania); Durdun, I. [S.C. GEOTEC S.A., Bucharest (Romania)

2007-07-01

22

Geological pattern formation by growth and dissolution in aqueous systems  

SciTech Connect

Although many geological processes take place on time scales that are very long compared with the human experience, essentially all geological processes, fast or slow, are far from equilibrium processes. Surprisingly often, geological processes lead to the formation of quite simple and distinctive patterns, which hint at an underlying simplicity in many complex geological systems.. The ability to predict the seasons was critically important to early human society, and Halley’s prediction of the return of the comet that bears his name is still considered to be a scientific milestone. Spatial patterns have also attracted attention because of their aesthetic appeal, which depends in subtle ways on a combination of regularity and irregularity. In recent decades, rapid growth in the capabilities of digital computers has facilitated the simulation of pattern formation processes, and computer simulations have become an important tool for evaluating theoretical concepts and for scientific discovery. Computer technology in combination with other technologies such as high resolution digital cameras, scanning microprobes (atomic force microscopy AFM), confocal microscopy, and scanning tunneling microscopy (STM), for example) has facilitated the quantitative characterization of patterns over a wide range of scales and has enabled rapid advances in our ability to understand the links between large scale pattern formation and microscopic processes. The ability to quantitatively characterize patterns is important because it enables a more rigorous comparison between the predictions of computer models and real world patterns and their formation.In some cases, the idea that patterns with a high degree of regularity have simple origins appears to be justified, but in other cases, such as the formation of almost perfectly circular stone rings due to freeze-thaw cycles simple patterns appear to be the consequence of quite complex processes. In other cases, it has been shown that very simple non-linear processes can lead to extremely complicated patterns, and that some apparently complex disordered systems can be described quantitatively in terms of simple fractal models.

Paul Meakin

2010-03-01

23

Combining geologic-process models and geostatistics for conditional simulation of 3-D subsurface heterogeneity  

NASA Astrophysics Data System (ADS)

The goal of simulation of aquifer heterogeneity is to produce a spatial model of the subsurface that represents a system such that it can be used to understand or predict flow and transport processes. Spatial simulation requires incorporation of data and geologic knowledge, as well as representation of uncertainty. Classical geostatistical techniques allow for the conditioning of data and uncertainty assessment, but models often lack geologic realism. Simulation of physical geologic processes of sedimentary deposition and erosion (process-based modeling) produces detailed, geologically realistic models, but conditioning to local data is limited at best. We present an aquifer modeling methodology that combines geologic-process models with object-based, multiple-point, and variogram-based geostatistics to produce geologically realistic realizations that incorporate geostatistical uncertainty and can be conditioned to data. First, the geologic features of grain size, or facies, distributions simulated by a process-based model are analyzed, and the statistics of feature geometry are extracted. Second, the statistics are used to generate multiple realizations of reduced-dimensional features using an object-based technique. Third, these realizations are used as multiple alternative training images in multiple-point geostatistical simulation, a step that can incorporate local data. Last, a variogram-based geostatistical technique is used to produce conditioned maps of depositional thickness and erosion. Successive realizations of individual strata are generated in depositional order, each dependent on previously simulated geometry, and stacked to produce a fully conditioned three-dimensional facies model that mimics the architecture of the process-based model. We demonstrate the approach for a typical subsea depositional complex.

Michael, H. A.; Li, H.; Boucher, A.; Sun, T.; Caers, J.; Gorelick, S. M.

2010-05-01

24

Travel Time Simulation of Radionuclides in a 200 m Deep Heterogeneous Clay Formation Locally Disturbed by Excavation  

Microsoft Academic Search

In Belgium, the Boom Clay Formation at a depth of 200 m below surface is being evaluated as a potential host formation for\\u000a the disposal of vitrified nuclear waste. The aim of this study is to model the transport of radionuclides through the clay,\\u000a taking into account the geological heterogeneity and the excavation induced fractures around the galleries in which

Marijke Huysmans; Arne Berckmans; Alain Dassargues

25

Opinion Formation in a Heterogenous Society  

Microsoft Academic Search

\\u000a Opinion formation and opinion leadership has attracted a lot of research among sociologists and physicists in the last decades.\\u000a The first concept of opinion leadership goes back to Lazarsfeld et al. [8] in 1944. Larzarsfeld et al. found out that during the presidential elections in 1940 interpersonal communication showed greater influence than direct\\u000a media effects. In their theory of two-step

Marie-Therese Wolfram

26

Transport of reactive solutes in heterogeneous porous formation  

Microsoft Academic Search

Transport and spreading behaviour of reactive solutes in heterogeneous porous formations is considered. Spatial variability is modeled by assuming a random space function (RSF) for the spatially variable properties. In the available literature, the effect of random spatial variability is mostly limited to considering the hydraulic conductivity as a RSF. In this thesis emphasis is given to the effects of

W. J. P. Bosma

1994-01-01

27

A Fundamental Study of Convective Mixing Contributing to Dissolution Trapping of CO2 in Heterogeneous Geologic Media using Surrogate Fluids and Numerical Modeling  

NASA Astrophysics Data System (ADS)

Geologic sequestration of carbon dioxide is considered as an important strategy to slow down global warming and hence climate change. Dissolution trapping is one of the primary mechanisms contributing to long-term storage of supercritical CO2 (scCO2) in deep saline geologic formations. When liquid scCO2 is injected into the formation, its density is less than density of brine. During the movement of injected scCO2 under the effect of buoyancy forces, it is immobilized due to capillary forces. With the progress of time, entrapped scCO2 dissolves in formation brine, and density-driven convective fingers are expected to be generated due to the higher density of the solute compared to brine. These fingers enhance mixing of dissolved CO2 in brine. The development and role of these convective fingers in mixing in homogeneous formations have been studied in past investigations. The goal of this study is to evaluate the contribution of convective mixing to dissolution trapping of scCO2 in naturally heterogeneous geologic formations via laboratory experiments and numerical analyses. To mimic the dissolution of scCO2 in formation brine under ambient laboratory conditions, a group of surrogate fluids were selected according to their density and viscosity ratios, and tested in different fluid/fluid mixtures and variety of porous media test systems. After selection of the appropriate fluid mixture, a set of experiments in a small test tank packed in homogeneous configurations was performed in order to analyze the fingering behavior. A second set of experiments was conducted for layered systems to study the effects of formation heterogeneity on convective mixing. To capture the dominant processes observed in the experiments, a Finite Volume based numerical code was developed. The model was then used to simulate more complex heterogeneous systems that were not represented in the experiments. Results of these analyses suggest that density-driven convective fingers that contributes to mixing in homogeneous formations may not be significantly contributing to mixing and hence dissolution trapping in heterogeneous formations. However, further experimental and modeling investigations are needed to investigate how the geologic architecture that defines the spatial distribution of low permeability zones contributes to overall dissolution trapping.

Illangasekare, Tissa; Agartan, Eliff; Trevisan, Luca; Cihan, Abdullah; Birkholzer, Jens; Zhou, Quanlin

2013-04-01

28

A Numerical Modeling Study of Effect of Heterogeneity on Capillary Trapping of Geologically Sequestrated CO2  

NASA Astrophysics Data System (ADS)

Heterogeneities at multiple scales influence migration and trapping of geologically sequestrated CO2 during injection and post-injection periods. Understanding of small-scale processes is crucial to device upscaling methodologies for incorporating them into macroscopic-scale models. The upscaled models are in turn used to get insights into the complex field-scale processes involved in the migration of supercritical CO2. Theoretical research based on numerical model analysis presented in this study focuses on capillary entrapment in homogeneous and heterogeneous small-scale and intermediate-scale laboratory experiments with surrogate fluids, presented in a companion presentation (Treviso et al., 2011). An improved understanding of pore-scale and larger scale processes on capillary entrapment may be achieved by combining pore-scale and macroscopic-scale modeling approaches. Capillarity controlled entrapped non-wetting phase saturation in macroscopic-scale models is generally either provided as an input parameter after laboratory scale measurements or estimated empirically. A particle trajectory modeling approach with pore-scale physics included is used to gain insights to development of physically-based models for the capillary entrapment in homogeneous and heterogeneous systems. The particle trajectory modeling generates functional relationships between phase saturation, entrapped phase saturation, hydraulic properties of the medium, and velocity of injected phase, which eventually are planned to be used for developing macroscopic scale models of capillary entrapment. The predictions of entrapped fluid saturation from the particle trajectory model are verified with measurements from the small scale experimental test systems. Macroscopic two-phase flow modeling approach with existing and modified constitutive models is tested by comparisons with both small-scale and intermediate-scale experimental results. T2VOC module based on TOUGH2 is used to simulate two-phase flow of surrogate fluids used in the laboratory experiments. Sensitivity of large-scale heterogeneities on capillary trapping is investigated by simulating the verified macroscopic two-phase flow model in deterministic and randomly generated heterogeneous systems.

Cihan, A.; Birkholzer, J. T.; Zhou, Q.; Trevisan, L.; Illangasekare, T. H.; Rodriguez, D.; Sakaki, T.

2011-12-01

29

Dispersion measurement as a method of quantifying geologic characterization and defining reservoir heterogeneity. Final report  

SciTech Connect

The main objective of this research project is to investigate dispersion as a method of quantifying geological characterization and defining reservoir heterogeneity in order to enhance crude oil recovery. The dispersion of flow of a reservoir rock (dispersion coefficient and dispersivity) was identified as one of the physical properties of a reservoir rock by measuring the mixing of two miscible fluids, one displacing the other in a porous medium. A rock was 100% saturated with a resident fluid and displaced by a miscible fluid of equal viscosity and equal density. Some specific experiments were performed with unequal densities. Produced fluid was analyzed by refractometer, nuclear reaction, electrical conductivity and X-ray scan. Several physical and flow characteristics were measured on the sand rock sample in order to establish correlations with the measured dispersion property. Absolute permeability, effective porosity, relative permeability, capillary pressure, the heterogeneity factor and electrical conductivity were used to better understand the flow system. Linear, transverse, 2-D and 3-D dispersions were measured and used to characterize the rock heterogeneity of the flow system. A new system of measuring dispersion was developed using a gas displacing gas system in a porous medium. An attempt was also made to determine the dispersion property of an actual reservoir from present day well log data on a producing well. 275 refs., 102 figs., 17 tabs.

Menzie, D.E.

1995-05-01

30

Scales of geological heterogeneity of a deep-water sand giant oil field  

SciTech Connect

To understand the levels of accuracy that can be placed upon different scales of reservoir description, turbidite intervals in part of the giant Wilmington oil field, California, have been numerically described at four scales of heterogeneity. The degree of accuracy of the description, in terms of real geologic variability, is found to diminish with increasing scale. At the microscale (grains and pores) and mesoscale (near well bore), the following flow units, listed in order of decreasing reservoir quality, were defined by relating various geologic and petrophysical properties: thick-bedded sand, thin-bedded sand, and shale. Mutual relationships among the geologic and petrophysical properties are a result of primary depositional processes. At the macroscale (interwell), shale beds are laterally continuous over long distances and probably isolate individual sands by acting as vertical permeability barriers. Petrophysical properties, such as permeability, vary between wells within an order of magnitude of measured values. The relationships among petrophysical properties and geologic properties established at the single-well scale are sometimes but not always predictable between wells. At the megascale (field wide), the turbidites were placed within the context of Vail's integrated sequence stratigraphy model, Walker's progradational submarine fan model, and Mutti's turbidite systems model to illustrate that there is not a unique interpretation when the overall size of a depositional system is larger than that of the data grid. At this scale, petrophysical properties are averaged over a large stratigraphic interval so that there is very little interwell predictability; however, the primary depositional control on gross petrophysical properties is maintained.

Slatt, R.M. (ARCO Oil and Gas Co., Plano, TX (USA)); Phillips, S. (ARCO Alaska, Inc., Anchorage (USA)); Boak, J.M. (Dept. of Energy, Washington, DC (USA)); Lagoe, M.B. (Univ. of Texas, Austin (USA))

1990-05-01

31

Geology of the Biwabik Iron Formation and Duluth Complex  

USGS Publications Warehouse

The Biwabik Iron Formation is a ???1.9 billion year-old sequence of iron-rich sedimentary rocks that was metamorphosed at its eastern-most extent by ???1.1 billion year-old intrusions of the Duluth Complex. The metamorphic recrystallization of iron-formation locally produced iron-rich amphiboles and other fibrous iron-silicate minerals. The presence of these minerals in iron-formation along the eastern part of what is known as the Mesabi Iron Range, and their potential liberation by iron mining has raised environmental health concerns. We describe here the geologic setting and mineralogic composition of the Biwabik Iron Formation in and adjacent to the contact metamorphic aureole of the Duluth Complex. The effects of metamorphism are most pronounced within a few kilometers of the contact, and decrease progressively away from it. The contact aureole has been divided into four metamorphic zones-each characterized by the composition and crystal structure of the metamorphic minerals it contains. The recrystallization of iron-formation to iron-rich amphibole minerals (grunerite and cummingtonite) and iron-pyroxene minerals (hedenbergite and ferrohypersthene) is best developed in zones that are most proximal to the Duluth Complex contact. ?? 2007 Elsevier Inc. All rights reserved.

Jirsa, M. A.; Miller, Jr. , J. D.; Morey, G. B.

2008-01-01

32

Geology of the Biwabik Iron Formation and Duluth Complex.  

PubMed

The Biwabik Iron Formation is a approximately 1.9 billion year-old sequence of iron-rich sedimentary rocks that was metamorphosed at its eastern-most extent by approximately 1.1 billion year-old intrusions of the Duluth Complex. The metamorphic recrystallization of iron-formation locally produced iron-rich amphiboles and other fibrous iron-silicate minerals. The presence of these minerals in iron-formation along the eastern part of what is known as the Mesabi Iron Range, and their potential liberation by iron mining has raised environmental health concerns. We describe here the geologic setting and mineralogic composition of the Biwabik Iron Formation in and adjacent to the contact metamorphic aureole of the Duluth Complex. The effects of metamorphism are most pronounced within a few kilometers of the contact, and decrease progressively away from it. The contact aureole has been divided into four metamorphic zones-each characterized by the composition and crystal structure of the metamorphic minerals it contains. The recrystallization of iron-formation to iron-rich amphibole minerals (grunerite and cummingtonite) and iron-pyroxene minerals (hedenbergite and ferrohypersthene) is best developed in zones that are most proximal to the Duluth Complex contact. PMID:17997209

Jirsa, Mark A; Miller, James D; Morey, G B

2007-10-01

33

Estimation of hydrologic properties of heterogeneous geologic media with an inverse method based on iterated function systems  

SciTech Connect

The hydrologic properties of heterogeneous geologic media are estimated by simultaneously inverting multiple observations from well-test data. A set of pressure transients observed during one or more interference tests is compared to the corresponding values obtained by numerically simulating the tests using a mathematical model. The parameters of the mathematical model are varied and the simulation repeated until a satisfactory match to the observed pressure transients is obtained, at which point the model parameters are accepted as providing a possible representation of the hydrologic property distribution. Restricting the search to parameters that represent fractal hydrologic property distributions can improve the inversion process. Far fewer parameters are needed to describe heterogeneity with a fractal geometry, improving the efficiency and robustness of the inversion. Additionally, each parameter set produces a hydrologic property distribution with a hierarchical structure, which mimics the multiple scales of heterogeneity often seen in natural geological media. Application of the IFS inverse method to synthetic interference-test data shows that the method reproduces the synthetic heterogeneity successfully for idealized heterogeneities, for geologically-realistic heterogeneities, and when the pressure data includes noise.

Doughty, C.A.

1996-05-01

34

Mechanism of spiral formation in heterogeneous discretized excitable media  

NASA Astrophysics Data System (ADS)

Spiral waves on excitable media strongly influence the functions of living systems in both a positive and negative way. The spiral formation mechanism has thus been one of the major themes in the field of reaction-diffusion systems. Although the widely believed origin of spiral waves is the interaction of traveling waves, the heterogeneity of an excitable medium has recently been suggested as a probable cause. We suggest one possible origin of spiral waves using a Belousov-Zhabotinsky reaction and a discretized FitzHugh-Nagumo model. The heterogeneity of the reaction field is shown to stochastically generate unidirectional sites, which can induce spiral waves. Furthermore, we found that the spiral wave vanished with only a small reduction in the excitability of the reaction field. These results reveal a gentle approach for controlling the appearance of a spiral wave on an excitable medium.

Kinoshita, Shu-ichi; Iwamoto, Mayuko; Tateishi, Keita; Suematsu, Nobuhiko J.; Ueyama, Daishin

2013-06-01

35

Dipole-Flow Test with a Tracer in Heterogeneous Formations  

NASA Astrophysics Data System (ADS)

We adopt a numerical flow model and introduce two new tracer transport models for simulating the dipole-flow test with a tracer (DFTT). The numerical DFTT flow model assumes axisymmetry and allows for the mixed-type boundary condition along the well-face and for heterogeneity in the hydraulic conductivity field. One of the new numerical transport models uses a streamtube approach whereas the other one uses a fully-implicit, finite-difference algorithm to simulate three-dimensional, axisymmetric tracer transport. Although the latter allows for cross-tube dispersion, it is an order of magnitude more computationally expensive. A comparison of the published analytical and the new numerical flow models shows that the uniform well-face flux simplifying assumption leads to an overestimation of the breakthrough curve peak arrival time and an underestimation of the peak magnitude. Through simulations with the dispersive transport model we learn that an increase in transverse dispersion corresponds to an increase in the magnitude of the peak concentration of the breakthrough curve. We conclude that the accuracy of the numerical streamtube models for cases of low transverse dispersivity and its computational efficiency is suitable for a qualitative analysis of the DFTT tracer transport through synthetic heterogeneous formations. We therefore use the numerical flow and streamtube models to simulate the DFTT in 20 random hydraulic conductivity fields generated using the geostatistical parameters of the Borden Aquifer. We show five of the fields and describe the effect of the heterogeneities on the breakthrough curves. By analyzing the breakthrough curves from all 20 fields we determine that on average a Borden-like formation results in a delay of the arrival time and a decrease in the magnitude of the breakthrough curve peak, an effect similar to that of an increase in hydraulic conductivity anisotropy ratio and dispersivity in a homogeneous aquifer. Finally, a field DFTT is analyzed considering the results from the new models and the simulations in heterogeneous media.

Sutton, D. J.; Kabala, Z. J.

2001-05-01

36

Heterogeneity and Scaling in Geologic Media: Applications to Transport in the Vadose and Saturated Zones  

SciTech Connect

Heterogeneity and Scaling in Geologic Media: Applications to Transport in the Vadose and Saturated Zones Stephen Brown, Gregory Boitnott, and Martin Smith New England Research In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. For sedimentary materials the length scales are: the pore scale (irregularities in grain surface roughness and cementation), the scale of grain packing faults (and the resulting correlated porosity structures), the scale dominated by sorting or winnowing due to depositional processes, and the scale of geomorphology at the time of deposition. We are studying the heterogeneity and anisotropy in geometry, permeability, and geophysical response from the pore (microscopic), laboratory (mesoscopic), and backyard field (macroscopic) scales. In turn these data are being described and synthesized for development of mathematical models. Eventually, we will perform parameter studies to explore these models in the context of transport in the vadose and saturated zones. We have developed a multi-probe physical properties scanner which allows for the mapping of geophysical properties on a slabbed sample or core. This device allows for detailed study of heterogeneity at those length scales most difficult to quantify using standard field and laboratory practices. The measurement head consists of a variety of probes designed to make local measurements of various properties, including: gas permeability, acoustic velocities (compressional and shear), complex electrical impedance (4 electrode, wide frequency coverage), and ultrasonic reflection (ultrasonic impedance and permeability). We can thus routinely generate detailed geophysical maps of a particular sample. With the exception of the acoustic velocity, we are testing and modifying these probes as necessary for use on soil samples. As a baseline study we have been characterizing the heterogeneity of a bench-size Berea Sandstone block. Berea Sandstone has long been regarded as a laboratory standard in rock properties studies, owing to its uniformity and ''typical'' physical properties. We find that both permeability and velocity exhibit complex heterogeneity at the centimeter scale. While some correlation with the outcropping of the bedding is apparent, much of the heterogeneity is not clearly associated with visual features. We are developing software tools to examine simultaneously pixel by pixel correlations among geophysical measurements, transport properties, and visual (photographic) texture and the dependence of these correlations on measurement scale. We find that certain pairs of physical quantities, such as P velocity and permeability for example, are distinctly correlated with one another at certain scales, but less obviously at other scales. Preliminary analyses of the Berea Sandstone data show that by simultaneous consideration of several physical properties the data can be separated into clusters of like properties which can be considered distinct facies. Apparently, identification of these facies, which could represent a limited range of fluid permeability, may be made by making joint geophysical measurements. Given various physical models for the dependence of the geophysical and transport properties on pore size, we expect that these observed correlations will provide conditioning and constraints to inversions for stochastic models of the internal structure of a specimen. For the study of soil heterogeneity at a wide range of scales, we are focusing on a local glacial deposit. This deposit is a glacial kame terrace of fluvial origin with multi-scale sedimentary structures comprised of unconsolidated sands, clays, and gravels. There are also many joints and faults in the unconsolidated sediments, allowing study of these as potential fluid flow conduits or barriers. We have obtained undisturbed soil samples from this site, allowing detailed laboratory study using similar methods to those described for the sandstone bl

Brown, Stephen R.

2003-06-01

37

Transient well-type flows in heterogenous formations  

NASA Astrophysics Data System (ADS)

The problem of averaging transient flows by sources of a given head boundary condition in heterogeneous formations of random conductivity is investigated. The study generalizes the recently developed mathematical model of average transient nonuniform flow [Indelman, 1996;Tartakovsky and Neuman, 1998a]. The latter allows calculating the mean head for sources of flux boundary condition and, as such, is not applicable to modeling common well flows. To account for the head condition, the source term in the local flow model is modeled by a random function proportional to the hydraulic conductivity. The local flow equations are further averaged in order to determine the mean flow variables. It is shown that the effective conductivity cannot be defined for arbitrary initial head distributions. This precludes deriving the mathematical model of an average transient flow with the head boundary condition. However, the average flow equations are derived for the important particular case of a uniformly distributed initial head. The effective conductivity tensor is defined for an arbitrary heterogeneous formation and analyzed in detail for isotropic media. It is shown that at the initial stage of the transient flow, the effective conductivity is larger than the conductivity arithmetic mean. The fundamental solution of the average flow equations (mean Green function), corresponding to the mean head distribution due to the instantaneous injection of the unit mean amount of water through a point source, is derived at first order in the conductivity variance and is compared with the mean head for the flux boundary condition.

Indelman, Peter

2003-03-01

38

A Formative Assessment of Geologic Time for High School Earth Science Students  

NSDL National Science Digital Library

Earth science courses typically include the concept of geological time. The authors of this study attempt to move past traditional assessment practices and develop a formative assessment of students' understanding of the construction of the geologic time scale and how it is interpreted. Through this approach students are challenged to conceptualize the geologic time scale by comparing it to a student-produced time scale for an older adult's life. This formative assessment allows the teacher to alter instruction based on students' feedback in order to maximize student understanding of geologic time.

2004-05-01

39

Heterogeneous and multiphase formation pathways of gypsum in the atmosphere.  

PubMed

Gypsum is a major sulphur-containing component of atmospheric particulate matter. To date, however, its formation pathways in the atmosphere are still not well known. In this study, several potentially important formation pathways of gypsum in atmospheric aerosols are proposed. We found that gypsum was formed in the humidifying-dehumidifying process of mixed sulphate and calcium salts. A deliquescent layer is crucial for the formation of gypsum from Ca(2+) and SO4(2-) ions. In particular, the presence of hygroscopic components, such as (NH4)2SO4 and Ca(NO3)2, is necessary for the conversion of calcium carbonate (CaCO3) upon heterogeneous reaction of either SO2 + O3 or SO2 + NO2 as well as anhydrous calcium sulphate (CaSO4) to form gypsum (CaSO4·2H2O) under ambient conditions. This study provides definitive evidence that synergistic effects in the physical and chemical processing of aerosol particles have a significant effect on their final chemical composition, mixing state and hygroscopic behaviour which dictates the environmental and climate impacts of the resulting aerosol. PMID:24107920

Ma, Qingxin; He, Hong; Liu, Yongchun; Liu, Chang; Grassian, Vicki H

2013-10-23

40

Free energy of embryo formation for heterogeneous multicomponent nucleation  

NASA Astrophysics Data System (ADS)

An approach for calculating the free energy of embryo formation for multicomponent heterogeneous nucleation has been developed. The approach is based on a differential version of the capillarity approximation. It is considered that a liquid droplet is formed due to the deposition of several gaseous compounds onto a nucleus containing a spherical insoluble core and nonvolatile soluble substances. The approach links interfacial free energies of the surfaces, the size of the insoluble core, and chemical characteristics of the substances with the free energy of the embryo formation. The free energy of embryo formation as well as the critical supersaturation are influenced by the ratios of the Henry's Law constants to the partial pressures of the species. Multicomponent nucleation with a dominant species can be described as a quasibinary nucleation of the dominant species and a virtual species. As an example, the free energy in a binary system of water and acid is considered. It is shown that water+acid nucleation on such nuclei is influenced by the acid, soluble nonvolatile compounds and insoluble substances.

Gorbunov, B.

1999-05-01

41

Sulfuric acid monohydrate: Formation and heterogeneous chemistry in the stratosphere  

NASA Astrophysics Data System (ADS)

We have investigated some thermodynamic properties (i.e., freezing/melting points) and heterogeneous chemistry of sulfuric acid monohydrate (SAM, H2SO4 · H2O), using a fast flow reactor coupled to a quadrupole mass spectrometer. The freezing point observations of thin liquid sulfuric acid films show that for acid contents between 75 and 85 wt % the monohydrate crystallizes readily at temperatures between 220 and 240 K on a glass substrate. Once formed, SAM can be thermodynamically stable in the H2O partial pressure range of (1-4)×10-4 torr and in the temperature range of 220-240 K. For a constant H2O partial pressure, lowering the temperature causes SAM to melt when the temperature and water partial pressure conditions are out of its stability regime. The reaction probability measurements indicate that the hydrolysis of N2O5 is significantly suppressed owing to the formation of crystalline SAM: The reaction probability on water-rich SAM (with higher relative humidity, or RH) is of the order of 10-3 at 210 K and decreases by more than an order of magnitude for the acid-rich form (with lower RH). The hydrolysis rate of ClONO2 on water-rich SAM is even smaller, of the order of 10-4 at 195 K. These reported values on crystalline SAM are much smaller than those on liquid solutions. No enhancement of these reactions is observed in the presence of HCl vapor at the stratospheric concentrations. In addition, Brunauer, Emmett, and Teller analysis of gas adsorption isotherms and photomicrography have been performed to characterize the surface roughness and porosities of the SAM substrate. The results suggest the possible formation of SAM in some regions of the middle- or low-latitude stratosphere and, consequently, much slower heterogeneous reactions on the frozen aerosols.

Zhang, Renyi; Leu, Ming-Taun; Keyser, Leon F.

1995-09-01

42

The geologic mapping of Venus using C-1 format: Sheets 75N254, 60N263  

NASA Astrophysics Data System (ADS)

The results of geologic mapping of Venus, produced on the base of Magellan images, are presented. We submit two C-1 format geologic maps with the appropriate legend. The mapping territory was taken from Venera 15 and 16 missions and geologic maps were composed. Magellan images allow us to divide some types of the plains units to determine the lava flow direction and to map with better accuracy.

Shalimov, I. V.

1992-12-01

43

Mesozoic marine tetrapod diversity: mass extinctions and temporal heterogeneity in geological megabiases affecting vertebrates.  

PubMed

The fossil record is our only direct means for evaluating shifts in biodiversity through Earth's history. However, analyses of fossil marine invertebrates have demonstrated that geological megabiases profoundly influence fossil preservation and discovery, obscuring true diversity signals. Comparable studies of vertebrate palaeodiversity patterns remain in their infancy. A new species-level dataset of Mesozoic marine tetrapod occurrences was compared with a proxy for temporal variation in the volume and facies diversity of fossiliferous rock (number of marine fossiliferous formations: FMF). A strong correlation between taxic diversity and FMF is present during the Cretaceous. Weak or no correlation of Jurassic data suggests a qualitatively different sampling regime resulting from five apparent peaks in Triassic-Jurassic diversity. These correspond to a small number of European formations that have been the subject of intensive collecting, and represent 'Lagerstätten effects'. Consideration of sampling biases allows re-evaluation of proposed mass extinction events. Marine tetrapod diversity declined during the Carnian or Norian. However, the proposed end-Triassic extinction event cannot be recognized with confidence. Some evidence supports an extinction event near the Jurassic/Cretaceous boundary, but the proposed end-Cenomanian extinction is probably an artefact of poor sampling. Marine tetrapod diversity underwent a long-term decline prior to the Cretaceous-Palaeogene extinction. PMID:19923126

Benson, Roger B J; Butler, Richard J; Lindgren, Johan; Smith, Adam S

2009-11-18

44

Statistical characterisation and stochastic parameterisation of sedimentary geological formations on their reaction capacity for sustainable groundwater quality management  

NASA Astrophysics Data System (ADS)

The fate of contaminants in groundwater aquifers is determined by the buffering capacity of those aquifers together with the composition of inflowing groundwater. A nationwide characterisation of the environmental geochemistry of the shallow subsurface (down to 30 m below surface) has been started in the Netherlands. This covers: 1. the reaction capacity of sediments as buffer for contamination, and 2. typical elemental composition of geological formations and the association between trace elements and major minerals. For this purpose, the Netherlands is subdivided into 27 so-called geotop regions each having a unique geological build-up of the shallow subsurface. Here, four types are recognised based on vertical hydrogeological build-up. The regions are statistically characterised on their geochemical composition using combinations of lithological class and geological formation as strata. The statistical data are subsequently coupled with a geological voxel model of the subsurface to stochastically parameterise the geological units on reaction capacity. This combined approach will be illustrated for the Dutch province Zeeland. Reaction capacity is considered as a series of geochemical characteristics that control acid/base condition, redox condition and sorption capacity. Five primary reaction capacity variables are characterised: 1. pyrite, 2. non-pyrite, reactive iron (oxides, siderite and glauconite), 3. clay fraction, 4. organic matter and 5. Ca-carbonate. Important reaction capacity variables that are determined by more than one solid compound are also deduced: 1. potential reduction capacity (PRC) by pyrite and organic matter, 2. cation-exchange capacity (CEC) by organic matter and clay content, 3. carbonate buffering upon pyrite oxidation (CPBO) by carbonate and pyrite. A statistical investigation of several hunderds of sediment analyses is performed that provides the geochemical properties of the sediments. Here, classification based on sedimentary facies may provide additional insight on spatial heterogeneity within lithological classes. A two-step stochastic algoritm is established for parameterisation of a geological voxel model. First, the cumulative frequency distribution (cfd) functions are calculated for the geochemical strata. Next, all voxels are classified into the geochemical strata and the cfd functions are used to put random reaction capacity variables into the geological voxel model. The result is a heterogeneous geochemical reaction capacity model of the subsurface having grid cells of 100x100x0.5 m. This model can be used in e.g. groundwater transport models or other instruments for groundwater quality management.

Griffioen, J.; Vermooten, S.; Keijzer, T.; Bakr, M.; Valstar, J.

2012-04-01

45

Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. [Jurassic Smackover Formation  

SciTech Connect

The objective of this project is to augment the National Reservoir Database (TORIS database), to increase our understanding of geologic heterogeneities that affect the recoveries of oil and gas from carbonate reservoirs in the State of Alabama, and to identify resources that are producible at moderate cost. This objective will be achieved through detailed geological, geostatistical, and engineering characterization of typical Jurassic Smackover Formation hydrocarbon, and engineering characterization of typical Jurassic Smackover Formation hydrocarbon reservoirs in selected productive fields in the state of Alabama. The results of these studies will be used to develop and test mathematical models for prediction of the effects of reservoir heterogeneities in hydrocarbon production. Work to date has focused on completion of Subtasks 1, 2, and 3 of this project. Work on Subtask 4 began in this quarter, and substantial additional work has been accomplished on Subtask 2. Subtask 1 included the survey and tabulation of available reservoir engineering and geological data. Subtask 2 comprises the geologic and engineering characterization of smackover reservoir lithofacies. Subtask 3 includes the geologic modeling of reservoir heterogeneities. Subtask 4 includes the development of reservoir exploitation methodologies for strategic infill drilling. 1 fig.

Mancini, E.A.

1990-01-01

46

Episodic and long-lived river incision along geologically heterogeneous passive margins  

NASA Astrophysics Data System (ADS)

Hillslopes and river profiles in the southern and central Appalachians and the Eastern Ghats of India do not display the characteristics of dynamic equilibrium expected for Mesozoic passive margins. Escarpments, gorges, and river knickpoints characterize many portions of the margin highlands and continental interior. Bedrock resistance is a first-order control on topography, but it is significantly altered by the history of erosion. A conceptual model of episodic drainage rearrangement and subsequent incision in these spatially varied geologic settings underscores the potential erosional heterogeneity of these long-eroding margins. Waves of heightened river incision extend deep into the margin, yielding steep topography on comparatively weak bedrock, and regional escarpments and plateau remnants that cross lithologic boundaries. Correlating major incision events through the landscape is possible using basin-wide analysis of river profile shape, but it is complicated by many factors including 1) the effects of rock resistance on rate and style of incision, 2) river dynamics that depend on sediment load, and 3) meander bend cutoffs. Knickpoint migration rates determined from terrace ages, in-channel erosion rate, and basin-wide correlations suggest that incision migrates upriver over millions of years. Renewed Quaternary incision by the James River, which has a large drainage basin likely captured during the Neogene, occurs by further knickpoint retreat that could be a response to erosional unloading and uplift, or simply to climate change. In one Appalachian drainage basin, modern channel morphology plus integration of erosion over the long term suggests that episodic, nonuniform erosion accounts for the majority of late Quaternary incision.

Harbor, D. J.; Gunnell, Y.; Hancock, G. S.

2011-12-01

47

Geological Study of Uranium Potential of the Kingston Peak Formation, Death Valley Region, California.  

National Technical Information Service (NTIS)

The results of a geological survey of the Kingston Peak Formation on the western slope of the Panamint Range near Death Valley are discussed. The geology of the Panamint mountains was mapped on topographic base maps of the Telescope Peak and Manly Peak qu...

D. Carlisle R. M. Kettler S. C. Swanson

1980-01-01

48

Geological study of uranium potential of the Kingston Peak Formation, Death Valley Region, California  

Microsoft Academic Search

The results of a geological survey of the Kingston Peak Formation on the western slope of the Panamint Range near Death Valley are discussed. The geology of the Panamint mountains was mapped on topographic base maps of the Telescope Peak and Manly Peak quadrangles. Radiometric suveys of the area were conducted using gamma ray spectrometers. Samples of the conglomerate were

D. Carlisle; R. M. Kettler; S. C. Swanson

1980-01-01

49

Evaluation of Displacement and Pore Pressure change Due to the Injections of Fluid in Geological Formations  

Microsoft Academic Search

Cap rock plays an important role in the geological sequestration of carbon dioxide capture and storage. It indicates the effectiveness of the storage formation controls the leakance of carbon dioxide and serves the need for geological repair and restoration. In this study, two analytical solutions based on the poroelastic theory were presented to evaluate the displacement and pore pressure change

K. Hsu; C. Chang

2010-01-01

50

Geology.  

National Technical Information Service (NTIS)

Geologic history and geographic distribution of Central New York's surface and subsurface mineral resources are described. Present and potential economic uses are identified; abandoned, semi-active, and active extraction sites are depicted; and resources ...

J. F. Davis

1970-01-01

51

Aerosol formation and heterogeneous chemistry in the atmosphere  

NASA Astrophysics Data System (ADS)

A general presentation of the Earth's atmosphere is provided, with the associated photochemical processes and oxidizing capacity. The article focuses on the atmospheric reactivity of Volatile Organic Compounds (VOCs) and the associated reaction products in the gas phase (ozone, oxygenated organic compounds, organic nitrates …) and in the particle phase, namely, the Secondary Organic Aerosols (SOA). The understanding of the processes leading to SOA formation is currently a "hot topic" because of: i) their high concentrations in the measured total organic matter, and ii) their potential important impacts on health and climate change. The initial theory of SOA formation was based on thermodynamic phase transfers of oxidized reaction products of VOCs, but it failed to explain the presence of high molecular weight (high-MW) compounds observed in SOA as well as a 1 to 2 orders of magnitude discrepancy between models and observations on the quantity of SOA. Therefore, different research investigations have been proposed such as heterogeneous and aqueous phase reactivity of organic compounds.

Monod, A.; Liu, Y.

2011-01-01

52

Stochastic Inversion of Pneumatic Cross-hole Tests and Barometric Pressure Fluctuations in Heterogeneous Unsaturated Formations  

NASA Astrophysics Data System (ADS)

The distributions of permeability and porosity are key factors that control airflow and gas phase transport in unsaturated formations. To understand the behavior of flow and transport in such formations, characterization procedure is a typical approach that has been widely applied to laboratories and fields. As is recognized by most investigations, this approach relies on accurate measurements, and more importantly, an adequate tool to interpret those measurements from experiments. This study presents a pneumatic inverse model that is capable to estimate the distributions of permeability (Ka) and porosity (n) with high resolution in heterogeneous unsaturated formations. Based on the concept of sequential successive linear estimator (SSLE), the developed model accounts for compressibility and density of air and estimates the geologic parameters using air pressure measurements from sequential cross-hole pneumatic pumping or injection tests. Four synthetic examples, including a one-dimensional well-posed, a horizontally two-dimensional, and two three-dimensional problems, are used to evaluate the developed model in estimating the distributions of permeability and porosity in unsaturated formations. Results of the numerical experiments are promising. The developed pneumatic inverse model can reconstruct the property (i.e., permeability and porosity) fields if the well-defined conditions are met. With relatively small number of available measurements, the proposed model can accurately capture the patterns and the magnitudes of estimated properties for unsaturated formations. Results of two complex three-dimensional examples show that the proposed model can map the fracture connectivity using relatively small number of subsurface pressure measurements and estimate and in shallow soil layers using spatial variations of barometric pressure.

Ni, C.-F.; Yeh, T.-C. J.; Hsu, H.-H.; Deng, Y.-T.

2009-04-01

53

Geologic factors controlling CO 2 storage capacity and permanence: case studies based on experience with heterogeneity in oil and gas reservoirs applied to CO 2 storage  

Microsoft Academic Search

A variety of structural and stratigraphic factors control geological heterogeneity, inferred to influence both sequestration\\u000a capacity and effectiveness, as well as seal capacity. Structural heterogeneity factors include faults, folds, and fracture\\u000a intensity. Stratigraphic heterogeneity is primarily controlled by the geometry of depositional facies and sandbody continuity,\\u000a which controls permeability structure. The permeability structure, in turn, has implications for CO2 injectivity

W. A. Ambrose; S. Lakshminarasimhan; M. H. Holtz; V. Núñez-López; S. D. Hovorka; I. Duncan

2008-01-01

54

Influence of culture heterogeneity in cell surface charge on adhesion and biofilm formation by Enterococcus faecalis.  

PubMed

Biofilm formation is an increasing problem in medicine, due to the intrinsic resistance of microorganisms in the biofilm mode of growth against the host immune system and antimicrobial therapy. Adhesion is an important step in biofilm formation, influenced, among other factors, by the surface hydrophobicities and charges of both the substratum and the adhering microorganisms. Enterococcus faecalis strains generally display subpopulations with different surface charges, expressed as bimodal zeta potential distributions. Two-thirds of E. faecalis strains isolated from clogged biliary stents displayed such heterogeneity of surface charges in culture. In this study, the influence of this culture heterogeneity on initial adhesion and subsequent biofilm formation was investigated. Heterogeneous strains were retained in higher numbers on polystyrene than homogeneous strains. Also, biofilm formation was much more pronounced for heterogeneous strains than for homogeneous strains. In a population enriched to display only one subpopulation, fewer bacteria were retained than in its original heterogeneous culture. Also, the enriched subpopulation formed less biofilm than its original heterogeneous culture. The presence of ox bile during adhesion resulted in fewer retained bacteria, although heterogeneous strains were still retained in significantly higher numbers than were homogeneous strains, and, in general, the presence of ox bile reduced biofilm formation. The initial adhesion and biofilm formation were independent of the presence of the gene encoding the enterococcal surface protein (esp) or the expression of gelatinase (GelE). It is concluded that heterogeneity in cell surface charge represents an advantage for bacteria in the colonization of surfaces. PMID:16547028

van Merode, Annet E J; van der Mei, Henny C; Busscher, Henk J; Krom, Bastiaan P

2006-04-01

55

AAPB-B - Committee offers revised exchange format for transferring geologic and petroleum data  

Microsoft Academic Search

Comments received since the publication of Exchange Format for Transfer of Geologic and Petroleum Data revealed the need for more flexibility with the AAPG-A Format (Shaw and Waller, 1989). This discussion resulted in the proposed AAPG-B version, which has unlimited number of data fields per record and unlimited number of records. Comment lines can appear anywhere, including in data records,

H. O. Waller; D. Guinn; M. Herkommer; B. Shaw

1990-01-01

56

Preliminary report on the geology and vertebrate fauna of the Miocene Manchar Formation, Sind, Pakistan  

Microsoft Academic Search

The Manchar Formation, a middle and upper Miocene fluvial sequence of sandstones, silts, and conglomerates, is exposed in a narrow north–south belt in the Lower Indus Basin of Sind Province, Pakistan. The formation, as measured in geological sections near Lake Manchar, can be divided into three parts differing in the proportions of the sandstones and silts. The contact with the

S. Mahmood Raza; John C. Barry; Grant E. Meyer; Lawrence Martin

1984-01-01

57

Formation Buffering Potential Pertaining to Geological Storage of Carbon Dioxide  

Microsoft Academic Search

One promising strategy for decreasing CO2 emissions to the atmosphere is carbon capture and storage in deep saline formations. Modeling efforts and the experimental measurements that support these efforts are critical to determining the fate of injected CO2. The focus of this work is CO2-water-rock interactions as they pertain to formation buffering potential. PHREEQC was used to model pH evolution

B. R. Ellis; C. A. Peters; M. Buschkuehle

2007-01-01

58

Thermal state and complex geology of a heterogeneous salty crust of Jupiter's satellite, Europa  

Microsoft Academic Search

The complex geology of Europa is evidenced by many tectonic and cryomagmatic resurfacing structures, some of which are “painted” into a more visible expression by exogenic alteration processes acting on the principal endogenic cryopetrology. The surface materials emplaced and affected by this activity are mainly composed of water ice in some areas, but in other places there are other minerals

Olga Prieto-Ballesteros; Jeffrey S. Kargel

2005-01-01

59

Geology of the Grand Canyon: Interpreting its rock layers and formation  

NSDL National Science Digital Library

In this culminating activity, students will be assessed on what they have learned during the Geology unit of their Earth Science class. After conducting classroom and field studies on geology students will utilize this knowledge to interpret the rock layers and formation of the Grand Canyon. Outside of class students will read/review a website and complete a study guide to be reviewed by the teacher to assess students' learning. Following teacher review of study guides, the next class period(s) will be a discussion and questioning session(s) on the formation of the Grand Canyon.

60

Modeling CO2 distribution in a heterogeneous sandstone reservoir: the Johansen Formation, northern North Sea  

NASA Astrophysics Data System (ADS)

The last few years there has been broad attention towards finding permanent storage options for CO2. The Norwegian continental margin holds great potential for storage in saline aquifers. Common for many of these reservoir candidates, however, is that geological data are sparse relative to thoroughly mapped hydrocarbon reservoirs in the region. Scenario modeling provides a method for estimating reservoir performances for potential CO2 storage sites and for testing injection strategies. This approach is particularly useful in the evaluation of uncertainties related to reservoir properties and geometry. In this study we have tested the effect of geological heterogeneities in the Johansen Formation, which is a laterally extensive sandstone and saline aquifer at burial depths of 2 - 4 km, proposed as a suitable candidate for CO2 storage by Norwegian authorities. The central parts of the Johansen Formation are underlying the operating hydrocarbon field Troll. In order not to interfere with ongoing gas production, a potential CO2 injection well should be located at a safe distance from the gas reservoir, which consequently implies areas presently without well control. From 3D seismic data, prediction of spatial extent of sandstone is possible to a certain degree, whereas intra-reservoir flow baffles such as draping mudstone beds and calcite cemented layers are below seismic resolution. The number and lateral extent of flow baffles, as well as porosity- and permeability distributions are dependent of sedimentary facies and diagenesis. The interpretation of depositional environment and burial history is thus of crucial importance. A suite of scenario models was established for a potential injection area south of the Troll field. The model grids where made in Petrel based on our interpretations of seismic data, wire line logs, core and cuttings samples. Using Eclipse 300 the distribution of CO2 is modeled for different geological settings; with and without the presence of pervasive low permeability draping mudstone layers, and with varying lateral extent of potential calcite cemented layers in 8 to 15 intra-reservoir depth levels. The modeled area covers 10 x 15.8 km, with a thickness of 110 m at the injection point. Simulations were run with an injection phase of 30 years plus 100 years of migration. The presence of meso-scale flow baffles causes a reduction in vertical permeability in addition to the facies related variation on the micro-scale. Scenarios including potential flow baffles as separate layers in the model grids were compared to scenarios in which the effect of flow baffles were included using harmonic mean average of vertical permeability. The subsequent differences in CO2 distribution are important in estimating the contact area between the plume front and reservoir brine. A heterogeneous reservoir with internal flow baffles is not necessarily a disadvantage as long as sufficient injectivity is maintained within individual sandstone bodies. In each scenario we aim to adapt a suitable injection strategy with respect to utilizing local effects such as the delimitation of gravitational flow, in order to increase reservoir sweep and maximize the effect of trapping mechanisms (i.e. residual, stratigraphic, mineral and dissolution).

Sundal, Anja; Miri, Rohaldin; Petter Nystuen, Johan; Dypvik, Henning; Aagaard, Per

2013-04-01

61

GEOGYN - a geological formation/drill string dynamics computer program  

SciTech Connect

This paper describes the initial development phase of a finite element computer program, GEODYN, capable of simulating the three-dimensional transient, dynamic response of a polycrystalline diamond compact (PDC) bit interacting with a non-uniform formation. The ability of GEODYN to simulate response variations attributable to hole size, hole bottom surface shapes, and formation material non-uniformities is demonstrated. Planned developmental phases will address the detailed response of a bottom-hole assembly (BHA), a drill ahead (rock penetration and removal) simulation, and ultimately, the response of the entire string.

Caskey, B.

1984-09-16

62

GEODYN: A geological formation/drillstring dynamics computer program  

SciTech Connect

This paper describes the initial development phase of a finite element computer program, GEODYN, capable of simulating the three-dimensional transient dynamic response of a polycrystalline diamond compact (PDC) bit interacting with a non-uniform formation. The ability of GEODYN to simulate response variations attributable to hole size, hole bottom surface shapes, and formation material non-uniformities is demonstrated. Planned developmental phases will address the detailed response of a bottom-hole assembly (BHA), a drill ahead (rock penetration and removal) simulation, and ultimately, the response of the entire string.

Baird, J.A.; Caskey, B.C.; Stone, C.M.; Tinianow, M.A.

1984-09-01

63

Study of effects of formation heterogeneity of carbon dioxide gas migration using a two-dimensional intermediate scale  

NASA Astrophysics Data System (ADS)

An important issue that needs attention in designing effective storage schemes for storage of CO2 in deep geologic formations is the assessment of risk of potential leakage. Leaking gas threatening the surface and groundwater sources and vegetation. In our research group, we have conducted experiments in soil columns to obtain a fundamental understanding of formation of gas and its migration. The results of these experiments demonstrated that a number of factors that include pressure gradients, temperature and formation heterogeneity, among others controls these processes. As a first step to upscale these findings from one-dimensional columns to multidimensional field settings, a set of experiments were conducted in a two-dimensional tank. The experiments are designed specifically to further improve our understanding of the effects of geologic heterogeneity on gas leakage. A two-dimensional tall tank with dimensions of 2.44m (H) x 0.41m (W) x 0.08m (D) was constructed. The tank was instrumented with 18 soil moisture sensors to measure the gas fraction and eight of which also measures temperature and electrical conductivity (EC). Pressure in the water phase was also measured at eight elevations along the length of the tank. The tank was packed with two test sands with known hydraulic and retention characteristics in a staggered pattern. The permeability of the coarser sand is roughly four times higher than that of the finer sand. There is no significant difference in porosity between the two sands. To simulate leakage from storage, gas-phase CO2 was injected at the bottom of the tank at a pressure of 35-70 kPa for durations changing from 6-24 hours. Soil moisture, EC, temperature, and water pressure were monitored during the experiment. It was observed that the gas phase CO2 first developed a preferential pathway mainly through the coarse soil. The data gathered from the pressure probes showed a significant pressure build-up during the gas injection, and a slow decrease after the gas injection was stopped. A qualitative analysis of the data from this single experiment shows; it took an hour, before CO2 was dissolved in a significant amount to be measured by an increase the electrical conduct of the fluid, however was this severely depending on the temperature. The two-phase system increases the water pressure, there is observed a direct correlation, between soil moisture content and water pressure. The heterogeneity was controlling the path of the CO2 gas. Additional experiments will be conducted to generate a comprehensive data set to evaluate the ability to existing multiphase modelling codes to capture the pressure changes observed in heterogeneous formations during CO2 leakage.

Lassen, R. N.; Sakaki, T.; Plampin, M. R.; Pawar, R. J.; Jensen, K. H.; Sonnenborg, T.; Illangasekare, T. H.

2011-12-01

64

Geologic setting of petroleum source rocks in Permian Phosphoria formation  

Microsoft Academic Search

The Permian Phosphoria Formation in the northwestern interior United States contains two phosphatic and organic-carbon-rich shale members - the Meade Peak Phosphatic Shale Member and the Retort Phosphatic Shale Member. These rocks were formed at the periphery of a foreland basin between the Paleozoic continental margin and the North American cratonic shelf. Maximum organic-carbon concentration is as much as 30

Maughan

1984-01-01

65

Enhanced CO2 Storage in Confined Geologic Formations  

Microsoft Academic Search

Many geoscientists endorse Carbon Capture and Storage (CCS) as a potential strategy\\u000afor mitigating emissions of greenhouse gases. Deep saline aquifers have been reported to\\u000ahave larger CO\\u000a2 storage capacity than other formation types because of their availability\\u000aworldwide and less competitive usage. This work proposes an analytical model for screening\\u000apotential CO\\u000a2 storage sites and investigates injection

Roland Tenjoh Okwen

2009-01-01

66

Engineering-geological conditions of the formations in the Western Thessaly basin, Greece  

NASA Astrophysics Data System (ADS)

An engineering-geological map of the Western Thessaly basin has been compiled, providing a valuable guide to both urban planning and industrial development of the wider area. This map contributes significantly to the optimization of land use and improved planning of technical work. Additionally, the engineering-geological conditions of the formations encountered in the Western Thessaly basin are examined. The formations are grouped into thirteen (13) engineering-geological entities, with regard to their geotechnical behaviour. This entire study was based on both in situ investigations and geotechnical information extracted from 1,039 boreholes. Furthermore, a landslide inventory map of the Western Thessaly basin has been compiled. In addition, the surface subsidence ruptures, due to ground-water overexploitation, have been examined in the eastern part of the study area.

Apostolidis, Emmanuel; Koukis, George

2013-09-01

67

Sulfuric acid monohydrate: Formation and heterogeneous chemistry in the stratosphere  

Microsoft Academic Search

We have investigated some thermodynamic properties (i.e., freezing\\/melting points) and heterogeneous chemistry of sulfuric acid monohydrate (SAM, H2SO4.H2O), using a fast flow reactor coupled to a quadrupole mass spectrometer. The freezing point observations of thin liquid sulfuric acid films show that for acid contents between 75 and 85 wt% the monohydrate crystallizes readily at temperatures between 220 and 240 K

Renyi Zhang; Ming-Taun Leu; Leon F. Keyser

1995-01-01

68

Regional geology and petroleum potential of Bakken Formation, southwestern Manitoba  

SciTech Connect

The Bakken Formation has been documented as an excellent petroleum source rock within the Williston basin and has, in some localities, been established as a producing zone. Recent exploration in the Daly field of southwestern Manitoba has led to the discovery and subsequent development of several oil pools within the middle member of the Bakken. The 21 active wells within these pools have produced 20,773.8 m/sup 3/ (130,667.2 bbl) of oil (40.2/degrees/ API) as of December 31, 1987. Through much of the Williston basin, the Bakken typically consists of three members: a lower, highly radioactive, black shale member; a middle siltstone member; and an upper black shale member (identical to the lower member). In southwestern Manitoba, the lower member is absent in most areas due to nondeposition and overstep of the overlying middle member. In these areas, the middle member unconformably overlies eroded red dolomitic shales of the Devonian Lyleton (Three Forks) Formation. The middle member is a relatively uniform blanket deposit averaging 4 m (13 ft) thick. It consists of interbedded tan to greenish-gray, very fine to medium-grained, well-sorted dolomitic sandstone and siltstone with angular to subrounded grains. Oil accumulation in the middle member is largely the result of stratigraphic trapping and appears, in part, to be localized where a basal sandstone (associated with middle member thickening) is concentrated in minor erosional lows on the Lyleton surface. The black shales of the upper member form a thin (2 m or 6.6 ft average), uniform cap throughout the map area and are overlain by the carbonates of the Mississippian Lodgepole Formation (Souris Valley Beds). Maximum thickness of the Bakken reaches 32 m (105 ft) in the Waskada field area, where the lower shale member is locally present.

Martiniuk, C.D.

1988-07-01

69

The Affect of Realistic Geologic Heterogeneity on Local and Regional P/S Amplitude Ratios Based on Numerical Simulations  

SciTech Connect

Regional seismic discriminants based on high-frequency P/S ratios reliably distinguish between earthquakes and explosions. However, P/S discriminants in the 0.5 to 3 Hz band (where SNR can be highest) rarely perform well, with similar ratios for earthquake and explosion populations. Variability in discriminant performance has spawned numerous investigations into the generation of S-waves from explosions. Several viable mechanisms for the generation of S-waves from explosions have been forwarded, but most of these mechanisms do not explain observations of frequency-dependant S-wave generation. Recent studies have focused on the affect of near-source scattering to explain the frequency-dependence of both S-wave generation and P/S discriminant performance. In this study we investigate near-source scatter through numerical simulation with a realistic geological model We have constructed a realistic, 3-dimensional earth model of the southern Basin and Range. This regional model includes detailed constraints at the Nevada Test Site (NTS) based on extensive geologic and geophysical studies. Gross structure of the crust and upper mantle is taken from regional surface-wave studies. Variations in crustal thickness are based on receiver function analysis and a compilation of reflection/refraction studies. Upper-crustal constraints are derived from geologic maps and detailed studies of sedimentary basin geometry throughout the study area. The free surface is based on a 10-meter digital elevation model (DEM) at NTS, and a 60-meter DEM elsewhere. The model extends to a depth of 150km, making it suitable for simulations at local and regional distances. Our simulation source is based on the 1993 Non-Proliferation Experiment explosion at the NTS. This shot was well recorded, offering ample validation data. Our validation tests include measures of long-period waveform fit and relative amplitude measurements for P and S phases. Our primary conclusion is that near-source topography and geologic complexity in the upper crust strongly contributed to the generation of S-waves from the NPE shot. When either geologic heterogeneity or topography is removed from the model, simulated amplitudes of regional S-waves are diminished. We also find that deeper sources scatter less energy off of topography and upper-crustal structures, resulting in diminished S-wave amplitudes with increasing source depth.

Myers, S C; Wagoner, J L; Preston, L; Smith, K; Larsen, S C

2005-07-11

70

Sudbury Project (University of Muenster-Ontario Geological Survey): Petrology, Chemistry, and Origin of Breccia Formations.  

National Technical Information Service (NTIS)

Within the Sudbury Project of the University of Muenster and the Ontario Geological Survey special emphasis was put on the breccia formations exposed at the Sudbury structure (SS) because of their crucial role for the impact hypothesis. They were mapped a...

D. Stoeffler A. Deutsch M. Avermann P. Brockmeyer R. Lakomy

1992-01-01

71

A methodology for the geological and numerical modelling of CO2 storage in deep saline formations  

Microsoft Academic Search

Several technological options have been proposed to stabilize and reduce the atmospheric concentrations of CO2 among which the most promising are the CCS technologies. The remedy proposed for large stationary CO2 sources as thermoelectric power plants is to separate the flue gas, capturing CO2 and to store it into deep subsurface geological formations. In order to support the identification of

R. Guandalini; F. Moia; G. Ciampa; C. Cangiano

2009-01-01

72

Formation and evolution of Lakshmi Planum, Venus: Assessment of models using observations from geological mapping  

Microsoft Academic Search

Detailed geological analysis of the Lakshmi Planum region of western Ishtar Terra results in the establishment of the sequence of major events during the formation and evolution of western Ishtar Terra, an important and somewhat unique area on Venus characterized by a raised volcanic plateau surrounded by distinctive folded mountain belts, such as Maxwell Montes. These mapping results and the

M. A. Ivanova; J HEADIII

2008-01-01

73

Method and device with adjustable focusing for measuring the electric resistivity of geological formations  

SciTech Connect

The method of the invention comprises determining the variation of the electric potential on both sides of a central electrode in a borehole, detecting the two levels of the borehole where the potential gradient is zero, and measuring the electric resistivity of the geological formation between these two levels.

Desbrandes, R.

1983-10-25

74

CO 2 Injection in Geological Formations: Determining Macroscale Coefficients from Pore Scale Processes  

Microsoft Academic Search

Carbon dioxide (CO2) injections in geological formations are usually performed for enhanced hydrocarbon recovery in oil and gas reservoirs and\\u000a storage and sequestration in saline aquifers. Once CO2 is injected into the formation, it propagates in the porous rock by dispersion and convection. Chemical reactions between\\u000a brine ions and CO2 molecules and consequent reactions with mineral grains are also important

F. Javadpour

2009-01-01

75

Petroleum geology of Woodbine Formation, Freestone County, Texas  

SciTech Connect

The Upper Cretaceous Woodbine Formation consists of clastics deposited in various southwestward-prograding environments on the margin of the subsiding East Texas basin. Depositional environments range from fluvial (in the north) to deltaic and a shelf strandplain (in the southwest). The Woodbine unconformably overlies the Lower Cretaceous Washita Group except in the basin axis and south of the Angelina-Caldwell flexure where deposition may have been continuous. Transgression by Eagle Ford seas closed the Woodbine deposition. Structural features in Freestone County include the East Texas basin, the Sabine uplift, the Mexia-Talco fault zone, and the East Texas salt province. Isopach thicknesses of the Woodbine range from 375 ft in the west to more than 900 ft in the east (basinward). Thickening on the downthrown side of the Mexia-Talco faults indicates syndepositional faulting, related to allochthonous rocks sliding over the Jurassic Louann Salt. Structural accumulations of petroleum have been discovered against faults and salt domes, but stratigraphic pinch-outs of the Woodbine's discontinuous lenticular sand bodies remain as excellent exploration opportunities.

Carden, M.

1986-05-01

76

Geological study of uranium potential of the Kingston Peak Formation, Death Valley Region, California  

SciTech Connect

The results of a geological survey of the Kingston Peak Formation on the western slope of the Panamint Range near Death Valley are discussed. The geology of the Panamint mountains was mapped on topographic base maps of the Telescope Peak and Manly Peak quadrangles. Radiometric suveys of the area were conducted using gamma ray spectrometers. Samples of the conglomerate were analyzed using delayed neutron, neutron activation, atomic absorption, and LECO analysis. It is concluded that uranium mineralization in the Favorable Submember is significant and further exploration is warranted. The monazite-fenotime related uranium and thorium mineralization in the Mountain Girl quartz pebble conglomerate is of no economic interest. (DMC)

Carlisle, D.; Kettler, R.M.; Swanson, S.C.

1980-09-01

77

Monte Carlo simulations of oscillations, chaos and pattern formation in heterogeneous catalytic reactions  

Microsoft Academic Search

Experimental studies employing surface science methods indicate that kinetic oscillations, chaos, and pattern formation in heterogeneous catalytic reactions often result from the interplay of rapid chemical reaction steps and relatively slow complementary processes such as oxide formation or adsorbate-induced surface restructuring. In general, the latter processes should be analysed in terms of theory of phase transitions. Therefore, the conventional mean-field

Vladimir P. Zhdanov

2002-01-01

78

Strategies for CO2 Sequestration in Geologic Formations and the Role of Geophysics  

NASA Astrophysics Data System (ADS)

Among proposed options for CO2 emissions mitigation, capture and sequestration is a promising solution that has the advantage of being able to cope with the large volume of CO2 involved, which will increase because of a growing energy demand. Consequently, an important component of the United States Department of Energy's (DOE) research and development program is dedicated to reducing CO2 emissions from power plants by developing technologies for capturing CO2 and for subsequent utilization and/or sequestration. Capture technologies target novel, low-cost approaches for separation and capture of CO2 from energy production and conversion facilities. Injection of CO2 into geologic formations is being practiced today by the petroleum industry for enhanced oil recovery, but it is not yet possible to predict with confidence storage volume, formation integrity and storage permanence over long time periods. Many important issues dealing with geologic storage, monitoring, and verification of fluids (including CO2) in underground oil and gas reservoirs, coal beds, and saline formations are now being addressed. Preliminary field tests are being conducted to confirm practical considerations, such as economics, safety, stability, permanence, and public acceptance. This paper presents an overview of DOE's research program in the area of CO2 sequestration and storage in geologic formations and specifically addresses the status of new knowledge, improved tools and enhanced technology for cost optimization, monitoring, modeling and capacity estimation. This paper also highlights those fundamental and applied studies, including field tests, sponsored by DOE that are measuring the degree to which CO2 can be injected and remain safely and permanently sequestered in geologic formations while concurrently assuring no adverse long term ecological impacts. Field geophysical techniques are playing a major role in these demonstrations, such as the Weyburn project in North Dakota and Canada, the Mountaineer Power Plant project in Ohio, and the Frio Formation project in Texas.

Klara, S. M.; Cohen, K.; Byrer, C.; Srivastava, R. D.

2003-12-01

79

The digital geologic map of Colorado in ARC/INFO format, Part C. Explanation sheet database  

USGS Publications Warehouse

This geologic map was prepared as a part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the published Geologic Map of Colorado (Tweto 1979). Consequently the digital version is at 1:500,000 scale using the Lambert Conformal Conic map projection parameters of the state base map. Stable base contact prints of the scribe sheets were scanned on a Tektronix 4991 digital scanner. The scanner automatically converts the scanned image to an ASCII vector format. These vectors were transferred to a VAX minicomputer, where they were then loaded into ARC/INFO. Each vector and polygon was given attributes derived from the original 1979 geologic map. This database was developed on a MicroVAX computer system using VAX V 5.4 nd ARC/INFO 5.0 software. UPDATE: April 1995, The update was done solely for the purpose of adding the abilitly to plot to an HP650c plotter. Two new ARC/INFO plot AMLs along with a lineset and shadeset for the HP650C design jet printer have been included. These new files are COLORADO.650, INDEX.650, TWETOLIN.E00 and TWETOSHD.E00. These files were created on a UNIX platform with ARC/INFO 6.1.2. Updated versions of INDEX.E00, CONTACT.E00, LINE.E00, DECO.E00 and BORDER.E00 files that included the newly defined HP650c items are also included. * Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Descriptors: The Digital Geologic Map of Colorado in ARC/INFO Format Open-File Report 92-050

Green, Gregory N.

1992-01-01

80

A Neumann expansion approach to flow through heterogeneous formations  

NASA Astrophysics Data System (ADS)

A stochastic approach is used for the study of flow through highly heterogeneous aquifers. The mathematical model is represented by a random partial differential equation in which the permeability and the porosity are considered to be random functions of position, defined by the average value, constant standard deviation and autocorrelation function characterized by the integral scale. The Laplace transform of the solution of the random partial differential equation is first written as a solution of a stochastic integral equation. This integral equation is solved using a Neumann series expansion. Conditions of convergence of this series are investigated and compared with the convergence of the perturbation series. For mean square convergence, the Neumann expansion method may converge for a larger range of variability in permeability and porosity than the classic perturbation method. Formal expressions for the average and for the correlation moments of the pressure are obtained. The influence of the variability of the permeability and porosity on pressure is analyzed for radial flow. The solutions presented for the pressure at the well, as function of the permeability coefficient of variation, may be of practical interest for evaluating the efficiency of well stimulation operations, such as hydraulic fracturing or acidizing methods, aimed at increasing the permeability around the well.

Zeitoun, D. G.; Braester, C.

1991-09-01

81

Evaluation of the geological relationships to gas hydrate formation and stability  

SciTech Connect

Although there are many publications pertaining to gas hydrates, their formation and stability in various geological conditions are poorly known. Therefore, for the same reasons and because of the very broad scope of our research, limited amount and extremely dispersed information, the study regions are very large. Moreover, almost without exception the geological environments controlling gas hydrates formation and stability of the studied regions are very complex. The regions studied (completed and partially completed - total 17 locations) during the reporting period, particularly the Gulf of Mexico and the Middle America Trench, are the most important in this entire research project. In the past, both of these regions have been extensively studied, the presence of gas hydrates confirmed and samples recovered. In our investigation it was necessary not only to review all previous data and interpretations, but to do a thorough analysis of the basins, and a critical evaluation of an previously reported and publicly available but not published information.

Not Available

1986-01-01

82

Methods and apparatus for measurement of electronic properties of geological formations through borehole casing  

DOEpatents

Methods and apparatus are provided for measuring electronic properties of geological formations and cement layers adjacent to cased boreholes including resistivities, polarization phenomena and dielectric constants. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. At least three voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of differential current conducted into formation in the vicinity of those electrodes. These measurements facilitate calculation of the resistivities of the adjacent geological formations as well as an indication of whether cement is present. Measurements of the differential voltage response to transient currents provide a measurement of the polarization phenomena in formation as well as the capacitance of the casing in contact with the formation which is useful for determining whether oil and gas are present. Lithological characteristics of the formation such as the presence or absence of clay can also be determined. A calibration procedure is provided for minimizing errors induced by variations in the casing. The device also may be placed within the pipe attached to a drill bit while drilling open holes.

Vail, III, William B. (Bothell, WA)

1989-01-01

83

Methods and apparatus for measurement of electronic properties of geological formations through borehole casing  

DOEpatents

Methods and apparatus are provided for measuring electronic properties of geological formations and cement layers adjacent to cased boreholes including resistivities, polarization phenomena and dielectric constants. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. At least three voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of differential current conducted into formation in the vicinity of those electrodes. These measurements facilitate calculation of the resistivities of the adjacent geological formations as well as an indication of whether cement is present. Measurements of the differential voltage response to transient currents provide a measurement of the polarization phenomena in formation as well as the capacitance of the casing in contact with the formation which is useful for determining whether oil and gas are present. Lithological characteristics of the formation such as the presence or absence of clay can also be determined. A calibration procedure is provided for minimizing errors induced by variations in the casing. The device also may be placed within the pipe attached to a drill bit while drilling open holes. 48 figs.

Vail, W.B. III.

1989-11-21

84

Methods and apparatus for measurement of electronic properties of geological formations through borehole casing  

DOEpatents

Methods and apparatus are provided for measuring electronic properties of geological formations and cement layers adjacent to cased boreholes including resistivities, polarization phenomena and dielectric constants. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. At least three voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the differential current conducted into formation in the vicinity of those electrodes. These measurements facilitate calculation of the resistivities of the adjacent geological formations as well as an indication of whether cement is present. Measurements of the differential voltage response to transient currents provide a measurement of the polarization phenomena in formation as well as the capacitance of the casing in contact with the formation which is useful for determining whether oil and gas present. Lithological characteristics of the formation such as the pressence or absence of clay can also be determined. A calibration procedure is provided for minimizing errors induced by variations in the casing. The device also may be placed within the pipe attached to a drill bit while drilling open holes.

Vail, III, William B. (Bothell, WA)

1991-01-01

85

Methods and apparatus for measurement of electronic properties of geological formations through borehole casing  

DOEpatents

Methods and apparatus are provided for measuring electronic properties of geological formations and cement layers adjacent to cased boreholes including resistivities, polarization phenomena and dielectric constants. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. At least three voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the differential current conducted into the formation in the vicinity of those electrodes. These measurements facilitate calculation of the resistivities of the adjacent geological formations as well as an indication of whether cement is present. Measurements of the differential voltage response to transient currents provide a measurement of the polarization phenomena in formation as well as the capacitance of the casing in contact with the formation which is useful for determining whether oil and gas are present. Lithological characteristics of the formation such as the presence or absence of clay can also be determined. A calibration procedure is provided for minimizing errors induced by variations in the casing. The device also may be placed within the pipe attached to a drill bit while drilling open holes. 48 figures.

Vail, W.B. III.

1991-08-27

86

Vertical stratification of subsurface microbial community composition across geological formations at the Hanford Site  

Microsoft Academic Search

Microbial diversity in subsurface sediments at the Hanford Site 300 Area near Richland, Washington State (USA) was investigated by analyzing samples recovered from depths of 9 to 52 m. Approximately 8000 near full-length 16S rRNA gene sequences were analyzed across geological strata that include a natural redox transition zone. These strata included the oxic coarse-grained Hanford formation, fine-grained oxic and

Xueju Lin; David W. Kennedy; Jim K. Fredrickson; Bruce N. Bjornstad; Allan Konopka

2011-01-01

87

CO2 leakage risk in 3D heterogeneous formations  

NASA Astrophysics Data System (ADS)

In this study we use a stochastic sensitivity analysis framework to evaluate the impact of 3D spatial heterogeneity in permeability on CO2 leakage risk. The leakage is defined as the total mass of CO2 moving into the overburden through the caprock-overburden interface, in both gaseous and liquid (dissolved) phases. The entropy-based framework has the ability to quantify the uncertainty associated with the input parameters/factors in the form of prior pdfs (probability density functions). Effective sampling of the prior pdfs enables us to explore the parameter space and systematically evaluate the individual and combined effects of the factors/parameters of interest on CO2 leakage risk. The parameters that are considered in the study include: mean, variance, and horizontal to vertical spatial anisotropy ratio for caprock permeability, and those same parameters for reservoir permeability. Given the sampled spatial variogram parameters, multiple realizations of permeability fields were generated using GSLIB subroutines. For each permeability field, a numerical simulator STOMP (water-salt-CO2-energy operational mode) is used to simulate the CO2 migration within the reservoir and caprock up to 50 years after injection. Due to intensive computational demand, a scalable version simulator, eSTOMP, is run on the Jaguar supercomputer. We then perform statistical analyses and summarize the relationships between the parameters of interest (mean/variance/anisotropy ratio of caprock/reservoir permeability) and CO2 leakage ratio. We will also present the effects of those parameters on CO2 plume radius and reservoir injectivity.

Hou, Z.; Murray, C. J.; Rockhold, M. L.

2011-12-01

88

Geological Carbon Sequestration in the Ohio River Valley: An Evaluation of Possible Target Formations  

NASA Astrophysics Data System (ADS)

The development of geological carbon sequestration within the Ohio River Valley is of major interest to the national electricity and coal industries because the Valley is home to a heavy concentration of coal-burning electricity generation plants and the infrastructure is impossible to eliminate in the short-term. It has been determined by Ohio's politicians and citizenry that the continued use of coal in this region until alternative energy supplies are available will be necessary over the next few years. Geologic sequestration is the only possible means of keeping the CO2 out of the atmosphere in the region. The cost of the sequestration effort greatly decreases CO2 emissions by sequestering CO2 directly on site of these plants, or by minimizing the distance between fossil-fueled generation and sequestration (i.e., by eliminating the cost of transportation of supercritical CO2 from plant to sequestration site). Thus, the practicality of CO2 geologic sequestration within the Ohio River Valley is central to the development of such a commercial effort. Though extensive work has been done by the Regional Partnerships of the DOE/NETL in the characterization of general areas for carbon sequestration throughout the nation, few projects have narrowed their focus into a single geologic region in order to evaluate the sites of greatest commercial potential. As an undergraduate of the Earth Sciences at Ohio State, I have engaged in thorough research to obtain a detailed understanding of the geology of the Ohio River Valley and its potential for commercial-scale carbon sequestration. Through this research, I have been able to offer an estimate of the areas of greatest interest for CO2 geologic sequestration. This research has involved petrological, mineralogical, geochemical, and geophysical analyses of four major reservoir formations within Ohio—the Rose Run, the Copper Ridge, the Clinton, and the Oriskany—along with an evaluation of the possible effects of injection into these saline reservoirs.

Dalton, T. A.; Daniels, J. J.

2009-12-01

89

Method for determining the dip angle of geological formations traversed by a borehole  

SciTech Connect

Acoustic signals are transmitted in a direction substantially perpendicular to the borehole axis, from different levels of at least three determined generatrices of the borehole wall. Reflected acoustic signals are received from the same direction at different levels of these generatrices. A train of signals is derived from each reflected acoustic signal and at least a group of significant elements of this signal train is selected. The groups of significant elements of the signals obtained for the different generatrices are correlated. The interval between signal trains corresponding to the maximum correlation corresponds to one and the same geological formation and is representative of the dip angle of this formation.

Desbrandes, R.; Norel, G.

1985-01-22

90

Heterogeneous chemistry of alkylamines with sulfuric acid: implications for atmospheric formation of alkylaminium sulfates.  

PubMed

The heterogeneous interaction of alkylamines with sulfuric acid has been investigated to assess the role of amines in aerosol growth through the formation of alkylaminium sulfates. The kinetic experiments were conducted in a low-pressure fast flow reactor coupled to an ion drift-chemical ionization mass spectrometer (ID-CIMS). The measurements of heterogeneous uptake of methylamine, dimethylamine, and trimethylamine were performed in the acidity range of 59-82 wt % H(2)SO(4) and between 243 and 283 K. Irreversible reactive uptakes were observed for all three alkylamines, with comparable uptake coefficients (gamma) in the range of 2.0 x 10(-2) to 4.4 x 10(-2). The measured gamma value was slightly higher in more concentrated sulfuric acid and at lower temperatures. The results imply that the heterogeneous reactions of alkylamines contribute effectively to the growth of atmospheric acidic particles and, hence, secondary organic aerosol formation. PMID:20192255

Wang, Lin; Lal, Vinita; Khalizov, Alexei F; Zhang, Renyi

2010-04-01

91

Firms formation and growth in the model with heterogeneous agents and monitoring  

Microsoft Academic Search

In this article we extend the agent-based model of firms' formation and growth proposed in [4]. In [4] the firms creation, expansion or contraction results from the interaction of heterogeneous utility maximizers. While the original model was able to replicate the power law distribution in the firms' sizes agents in the model set their utility maximizing effort levels completely freely

Peter Marko

2008-01-01

92

A coupled local–global upscaling approach for simulating flow in highly heterogeneous formations  

Microsoft Academic Search

A new technique for generating coarse scale models of highly heterogeneous subsurface formations is developed and applied. The method uses generic global coarse scale simulations to determine the boundary conditions for the local calculation of upscaled properties (permeability or transmissibility). An iteration procedure assures consistency between the local and global calculations. Transport processes are simulated using a subgrid velocity reconstruction

Y. Chen; L. J. Durlofsky; M. Gerritsen; X. H. Wen

2003-01-01

93

Simulation of Dispersion in Heterogeneous Porous Formations: Statistics, First-Order Theories, Convergence of Computations  

Microsoft Academic Search

This paper discusses the results of numerical analysis of dispersion of passive solutes in two-dimensional heterogeneous porous formations. Statistics of flow and transport variables, the accuracy and the role of approximations implicit in existing first-order theories, and the convergence of computational results are investigated. The results suggest that quite different rates of convergence with Monte Carlo runs hold for different

Alberto Bellin; Paolo Salandin; Andrea Rinaldo

1992-01-01

94

Modeling Heterogeneous CINO2 Formation, Chloride Availability, and Chlorine Cycling in Southeast Texas  

EPA Science Inventory

Nitryl chloride (ClNO2) mixing ratios above 1 ppbv have been measured off the coast of Southeast Texas. ClNO2 formation, the result of heterogeneous N205 uptake on chloride-containing aerosols, has a significant impact on oxidant form...

95

CO2 Plume Estimation with Automatic Calibration of TOUGH Model for Carbon Sequestration in Geological Formations  

NASA Astrophysics Data System (ADS)

In order to assure safe carbon sequestration in geological formations, estimation of the CO2 plume from monitoring data is needed. We investigate methodologies to use field measurements and numerical simulations to find the plume position and to obtain a better understanding of the interaction of different mechanisms that govern the CO2 flow in the geological formation. The challenge is to be able to give an accurate prognosis of the plume location while dealing with uncertainties and model error. We use the TOUGH2 program, which is a numerical simulator for multi-phase fluid and heat flow in porous and fractured media, along with the ECO2N module, specific for CO2 flow in brine. This model describes the coupling of flow and geological processes. We also use the optimization program ORBIT to calibrate the model parameters. ORBIT (Optimization by Radial Basis Function Interpolation in Trust-Regions) has proven to be computationally efficient for environmental models that are computationally expensive. It is a derivative-free method, which makes it easier to use in conjunction with a complex nonlinear simulation model. We use a three-dimensional saline aquifer for the application.

Espinet, A. J.; Shoemaker, C. A.; Doughty, C.

2009-12-01

96

Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations. Volume 10. Repository Preconceptual Design Studies: Granite.  

National Technical Information Service (NTIS)

This volume, Volume 10 ''Repository Preconceptual Design Studies: Granite,'' is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations,'' Y/OWI/TM-36, which supplements the ''Contribution to Draft Gener...

1978-01-01

97

Multiple scale physical and numerical modeling for improved understanding of mechanisms of trapping and leakage of CO2 in deep geologic formations  

NASA Astrophysics Data System (ADS)

The fundamental processes associated with trapping and leakage of CO2 in deep geologic formations are complex. Formation heterogeneity manifested at all scales is expected to affect capillary and dissolution trapping and leakage of gaseous CO2 to the shallow subsurface. Research is underway to improve our fundamental understanding of trapping and leakage. This research involves experimentation in multiple scales and modeling focusing on effects of formation heterogeneity. The primary hypothesis that drives this research is that when the effects of heterogeneity on entrapment and leakage are understood, it will be possible to design more effective and safe storage schemes. Even though field investigations have some value in understanding issues related to large scale behavior and performance assessment, a fundamental understanding of how the heterogeneity affects trapping is difficult or impossible to obtain in field settings. Factors that contribute to these difficulties are the inability to fully characterize the formation heterogeneity at all scales of interest and lack of experimental control at very high depths. Intermediate scale physical model testing provides an attractive alternative to investigate these processes in the laboratory. Heterogeneities can be designed using soils with known properties in test tanks and the experiments can be conducted under controlled conditions to obtain accurate data. Conducting laboratory experiments under ambient pressure and temperature conditions to understand the processes that occur in deep formations poses many challenges. This research attempts to address such challenges and demonstrates how this testing approach could be used to generate useful data. The experiments involve the use of test systems of hierarchy of scales from small to intermediate scale tanks (~ 5 m) and long columns (~ 4.5 m). These experiments use surrogate fluids to investigate both capillary and solubility trapping in homogeneous and heterogeneous systems. A traversing x-ray scanning system is used to monitor the advancement of the plume during and after injection and to measure the residual (trapped) CO2 saturation. Dissolution of a surrogate non-wetting fluid in a surrogate wetting fluid is analyzed in small and large tanks. We test the numerical models that are capable of simulating two-phase flow and density driven flow as a result of dissolution by using the experimental data. Verified models are used to further evaluate the effect of capillary and solubility trapping in complex heterogeneous environments. During leakage, under different pressure and temperature conditions, dissolved CO2 may come back out of solution (exsolve), but the fundamental triggering mechanisms of this process in porous media are not yet well understood. An extensive series of column experiments has been conducted to investigate the factors that control the rates of CO2 gas bubble nucleation, growth, and migration. Results indicate that the saturation pressure (i.e. the amount of CO2 dissolved into the injected water) and heterogeneity both significantly affect the gas formation and migration, whereas the injection rate has less of an effect. These column experiments will soon be upscaled to an intermediate-scale two-dimensional tank to investigate the behaviour of the CO2 gas-water-soil system in more complex geological environments.

Illangasekare, T.; Plampin, M.; Trevisan, L.; Agartan, E.; Mori, H.; Sakaki, T.; Cihan, A.; Birkholzer, J.; Zhou, Q.; Pawar, R.; Zyvoloski, G.

2012-04-01

98

AAPB-B - Committee offers revised exchange format for transferring geologic and petroleum data  

SciTech Connect

Comments received since the publication of Exchange Format for Transfer of Geologic and Petroleum Data revealed the need for more flexibility with the AAPG-A Format (Shaw and Waller, 1989). This discussion resulted in the proposed AAPG-B version, which has unlimited number of data fields per record and unlimited number of records. Comment lines can appear anywhere, including in data records, to help document data transfer. Data dictionary hooks have been added. The American Petroleum Institute has assisted by supplying an ANSI envelope for this format, which will permit the electronic transfer with verification of data sets between any two ANSI installations. The American Association of Petroleum Geologists Database Standards Subcommittee invites comments on the proposed revisions, and will review the suggestions when it meets June 2 in San Francisco.

Waller, H.O.; Guinn, D. (Texaco, Houston, TX (USA)); Herkommer, M. (Petrospec Computer Inc., Garland, TX (USA)); Shaw, B. (AAPG Computer Applications Committee, Houston, TX (USA))

1990-04-01

99

Heterogeneity and Reservoir Quality of Yabus and Samaa Formations, Agordeed Field, Melut Rift Basin, Sudan  

NASA Astrophysics Data System (ADS)

The Tertiary Yabus and Samaa Formations occur within the Melut Rift basin of interior Sudan which is regionally linked to the central and west African rift system. Yabus and Samaa Formations in Agordeed oil field are ones of the most productive oil reservoirs in Melut basin and are composed of sandstones and mudstones lithofacies that differ in size and length along and across the basin. The reservoir sandstone, which occurs at shallow burial depth, deposited within fluvial/lacustrine environments. This work aims to describe and characterize the reservoir heterogeneity and to investigate their impact on reservoir quality and architecture. This study employed a multidisciplinary and integrated approach that investigated and synthesized stratigraphic, sedimentological, cores, logs, petrographical, petrophysical and seismic data from Agordeed oil field. The stratigraphic and lithofacies analysis indicated that Yabus and Samaa formations vary systematically in their facies, sequences and stacking patterns within the basin. Reservoir heterogeneity exists at multiple scales, where reservoir sandstones macro- and micro scale heterogeneity shows vertical and lateral variations along and across the basin. These variations reflect the tectonic, depositional and post depositional controls within the proximal to distal fluvial, prodelta and lacustrine environments. The porosity and permeability distributions are controlled by the heterogeneities within the reservoir formation, such as stratigraphic layering, facies, diagenetic processes, and fracturing. Porosity is enhanced by extensive fracturing and grain dissolution creating intergranular, intragranular and moldic porosity. In addition, permeability is also increased by fractures connecting separated the buildups, that affect directly the reservoir quality. Assessing the different scales of heterogeneity is important to understand their impact on reservoir quality and architecture in Agordeed Field.

Badi, Amani; Ali, Omer; Farwa, Abdalla; Abdullatif, Osman

2010-05-01

100

Method of detecting leakage from geologic formations used to sequester CO.sub.2  

DOEpatents

The invention provides methods for the measurement of carbon dioxide leakage from sequestration reservoirs. Tracer moieties are injected along with carbon dioxide into geological formations. Leakage is monitored by gas chromatographic analyses of absorbents. The invention also provides a process for the early leak detection of possible carbon dioxide leakage from sequestration reservoirs by measuring methane (CH.sub.4), ethane (C.sub.2H.sub.6), propane (C.sub.3H.sub.8), and/or radon (Rn) leakage rates from the reservoirs. The invention further provides a method for branding sequestered carbon dioxide using perfluorcarbon tracers (PFTs) to show ownership.

White, Curt (Pittsburgh, PA); Wells, Arthur (Bridgeville, PA); Diehl, J. Rodney (Pittsburgh, PA); Strazisar, Brian (Venetia, PA)

2010-04-27

101

Heterogeneous formation of polar stratospheric clouds - Part 2: Nucleation of ice on synoptic scales  

NASA Astrophysics Data System (ADS)

This paper provides unprecedented evidence for the importance of heterogeneous nucleation, likely on solid particles of meteoritic origin, and of small-scale temperature fluctuations, for the formation of ice particles in the Arctic stratosphere. During January 2010, ice PSCs (Polar Stratospheric Clouds) were shown by CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) to have occurred on a synoptic scale (~ 1000 km dimension). CALIPSO observations also showed widespread PSCs containing nitric acid trihydrate (NAT) particles in December 2009, prior to the occurrence of synoptic-scale regions of ice PSCs during mid-January 2010. We demonstrate by means of detailed microphysical modeling along air parcel trajectories that the formation of these PSCs is not readily reconciled with expectations from the conventional understanding of PSC nucleation mechanisms. The measurements are at odds with the previous laboratory-based understanding of PSC formation, which deemed direct heterogeneous nucleation of NAT and ice on preexisting solid particles unlikely. While a companion paper (Part 1) addresses the heterogeneous nucleation of NAT during December 2009, before the existence of ice PSCs, this paper shows that also the large-scale occurrence of stratospheric ice in January 2010 cannot be explained merely by homogeneous ice nucleation but requires the heterogeneous nucleation of ice, e.g. on meteoritic dust or preexisting NAT particles. The required efficiency of the ice nuclei is surprisingly high, namely comparable to that of known tropospheric ice nuclei such as mineral dust particles. To gain model agreement with the ice number densities inferred from observations, the presence of small-scale temperature fluctuations, with wavelengths unresolved by the numerical weather prediction models, is required. With the derived rate parameterization for heterogeneous ice nucleation we are able to explain and reproduce CALIPSO observations throughout the entire Arctic winter 2009/2010.

Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Hoyle, C. R.; Grooß, J.-U.; Dörnbrack, A.; Peter, T.

2013-04-01

102

Geological evolution and analysis of confirmed or suspected gas hydrate localities. Volume 14, Basin analysis, formation and stability of gas hydrates of the Timor Trough.  

National Technical Information Service (NTIS)

Geological factors controlling the formation, stability, and distribution of gas hydrates in the Timor Trough region were investigated by basin analysis. Geological, geophysical, and geochemical data from the region were assembled and evaluated to determi...

P. D. Finley J. Krason

1989-01-01

103

An effect of CO2 leakage from deep geological formations on the quality of shallow aquifers  

NASA Astrophysics Data System (ADS)

Injection of CO2 into deep geological formations is a promising technique for Sequestration of large amount of CO2. If some fraction of the stored CO2 were to leak and reach shallow groundwater aquifers, however, it would lead to geochemical alteration that could have detrimental effects on the water quality. A series of experiments were performed on dissolution kinetics of a trace metal, galena, to evaluate the change in groundwater pH and the enhanced dissolution as carbon dioxide introduces into the aquifer. The conventional rate law was applied to obtain reaction parameters on dissolution kinetics for further modeling studies. The results from batch experiments and kinetic analysis were applied to develop a 1D mathematical model to simulate the fate and transport of dissolved trace metals in shallow aquifers. Results show that CO2 dissolution in groundwater aquifers can solubilize trace metals to levels that exceed drinking water standards. This approach allows for a reasonable assessment of the risks on tha quality of freshwater aquifers due to the escape of CO2 from deep geological formations.

Wang, Sookyun; Nam, Ji Eun

2013-04-01

104

Heterogeneous Video Transcoding to Lower Spatio-Temporal Resolutions and Different Encoding Formats  

Microsoft Academic Search

In this work, transcoding of pre-encoded MPEG-1, 2 video into lower bit rates is realized through altering the coding algorithm into H.261\\/H.263 standards with lower spatio-temporal resolutions. For this heterogeneous transcoding, we extract and compose a set of candidate motion vectors, from the incoming bit stream, to comply with the encoding format of the output bit stream. For the spatial

Tamer Shanableh; Mohammed Ghanbari

2000-01-01

105

Effects of density and mutual solubility of CO2-brine system on CO2 storage in geological formations  

Microsoft Academic Search

The fluid properties of CO2 injected into geological formations for subsurface storage are strongly affected by the specific formation conditions of pressure, temperature and salinity. The conditions affect fluid solubility and density, and their effects on subsurface CO2 storage efficacy are investigated. Several common EOS and solubility models were investigated; their accuracy and applicability are briefly discussed. We evaluated the

C. Lu; W. Han; S. Lee; D. Thorne; R. Esser; B. McPherson

2008-01-01

106

Geologic setting, petrophysical characteristics, and regional heterogeneity patterns of the Smackover in southwest Alabama. Draft topical report on Subtasks 2 and 3  

SciTech Connect

This is the draft topical report on Subtasks 2 and 3 of DOE contract number DE-FG22-89BC14425, entitled ``Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity.`` This volume constitutes the final report on Subtask 3, which had as its primary goal the geological modeling of reservoir heterogeneity in Smackover reservoirs of southwest Alabama. This goal was interpreted to include a thorough analysis of Smackover reservoirs, which was required for an understanding of Smackover reservoir heterogeneity. This report is divided into six sections (including this brief introduction). Section two, entitled ``Geologic setting,`` presents a concise summary of Jurassic paleogeography, structural setting, and stratigraphy in southwest Alabama. This section also includes a brief review of sedimentologic characteristics and stratigraphic framework of the Smackover, and a summary of the diagenetic processes that strongly affected Smackover reservoirs in Alabama. Section three, entitled ``Analytical methods,`` summarizes all nonroutine aspects of the analytical procedures used in this project. The major topics are thin-section description, analysis of commercial porosity and permeability data, capillary-pressure analysis, and field characterization. ``Smackover reservoir characteristics`` are described in section four, which begins with a general summary of the petrographic characteristics of porous and permeable Smackover strata. This is followed by a more-detailed petrophysical description of Smackover reservoirs.

Kopaska-Merkel, D.C.; Mann, S.D.; Tew, B.H.

1992-06-01

107

A workflow for handling heterogeneous 3D models with the TOUGH2 family of codes: Applications to numerical modeling of CO 2 geological storage  

Microsoft Academic Search

This paper is addressed to the TOUGH2 user community. It presents a new tool for handling simulations run with the TOUGH2 code with specific application to CO2 geological storage. This tool is composed of separate FORTRAN subroutines (or modules) that can be run independently, using input and output files in ASCII format for TOUGH2. These modules have been developed specifically

Pascal Audigane; Christophe Chiaberge; Frédéric Mathurin; Julie Lions; Géraldine Picot-Colbeaux

2011-01-01

108

Role of geomechanically grown fractures on dispersive transport in heterogeneous geological formations.  

PubMed

A second order in space accurate implicit scheme for time-dependent advection-dispersion equations and a discrete fracture propagation model are employed to model solute transport in porous media. We study the impact of the fractures on mass transport and dispersion. To model flow and transport, pressure and transport equations are integrated using a finite-element, node-centered finite-volume approach. Fracture geometries are incrementally developed from a random distributions of material flaws using an adoptive geomechanical finite-element model that also produces fracture aperture distributions. This quasistatic propagation assumes a linear elastic rock matrix, and crack propagation is governed by a subcritical crack growth failure criterion. Fracture propagation, intersection, and closure are handled geometrically. The flow and transport simulations are separately conducted for a range of fracture densities that are generated by the geomechanical finite-element model. These computations show that the most influential parameters for solute transport in fractured porous media are as follows: fracture density and fracture-matrix flux ratio that is influenced by matrix permeability. Using an equivalent fracture aperture size, computed on the basis of equivalent permeability of the system, we also obtain an acceptable prediction of the macrodispersion of poorly interconnected fracture networks. The results hold for fractures at relatively low density. PMID:22181492

Nick, H M; Paluszny, A; Blunt, M J; Matthai, S K

2011-11-04

109

Modulation format identification in heterogeneous fiber-optic networks using artificial neural networks.  

PubMed

We propose a simple and cost-effective technique for modulation format identification (MFI) in next-generation heterogeneous fiber-optic networks using an artificial neural network (ANN) trained with the features extracted from the asynchronous amplitude histograms (AAHs). Results of numerical simulations conducted for six different widely-used modulation formats at various data rates demonstrate that the proposed technique can effectively classify all these modulation formats with an overall estimation accuracy of 99.6% and also in the presence of various link impairments. The proposed technique employs extremely simple hardware and digital signal processing (DSP) to enable MFI and can also be applied for the identification of other modulation formats at different data rates without necessitating hardware changes. PMID:22714229

Khan, Faisal Nadeem; Zhou, Yudi; Lau, Alan Pak Tao; Lu, Chao

2012-05-21

110

Importance of Charles Lyell’s works for the formation of scientific geological ideology  

Microsoft Academic Search

Ch. Lyell’s works, the main work among which entitled Principles of Geology was published 180 years ago in 1830, created a new concept and laid the groundwork for modern geological science, methods\\u000a for the study of geological processes and geological history based on the investigation of recent environments and processes.\\u000a These propositions with natural corrections are also used in geological

V. G. Kuznetsov

2011-01-01

111

The Vicksburg Formation of Texas: Depositional systems distribution, sequence stratigraphy, and petroleum geology  

SciTech Connect

The lower Oligocene Vicksburg Formation of the Gulf Coastal plain contains major petroleum reservoirs in the Rio Grande embayment and is an economically viable target in other areas of Texas. Knowledge of the distribution of Vicksburg depositional systems is essential to understanding sandstone concentrations and, therefore, is fundamental to effective exploration and production of the Vicksburg section. The depositional setting of the Vicksburg reservoirs, their position in a sequence stratigraphic framework, and the influence these factors have on the petroleum geology of the Vicksburg are the focus of this paper. Surface and subsurface geological and geophysical data provided the framework for an analysis of the depositional systems and the petroleum geology of the Vicksburg. The two primary Texas Vicksburg depocenters, the Rio Grande embayment and the Houston embayment, are separated by the San Marcos arch, a deep-rooted structural nose. Within the embayments, sand-rich deltaic complexes merged along strike with barrier/strand plains. Contemporaneous growth faulting controlled depositional patterns of shelf-edge deltas in the Rio Grande embayment, but had only a minor effect on the configuration of the shelfal deltas in the Houston embayment. Smaller wave-dominated shelf delta complexes interspersed with barrier/strand plains extended across the San Marcos arch. Updip of these sandy paralic depocenters, fluvial systems traversed mud-rich coastal plain units. Seaward of the paralic systems, sand and mud deposits prograded across and built up over the relict Jackson shelf and shelf-margin shales. These depositional complexes are contained in the systems tracts of one eustatic (Exxon) sequence. Vicksburg production from each of the three structural regions of Texas is characterized by reservoirs from different systems tracts and of distinct, different depositional origins.

Combes, J.M. (Amoco Production Co., Tulsa, OK (United States))

1993-11-01

112

Heterogeneous Chemistry of Carbonyls and Alcohols With Sulfuric Acid: Implications for Secondary Organic Aerosol Formation  

NASA Astrophysics Data System (ADS)

Recent environmental chamber studies have suggested that acid-catalyzed particle-phase reactions of organic carbonyls lead to multifold increases in secondary organic aerosol (SOA) mass and acid-catalyzed reactions between alcohols and aldehydes in the condensed phase lead to the formation of hemiacetals and acetals, also enhancing secondary organic aerosol growth. The kinetics and mechanism of the heterogeneous chemistry of carbonyls and alcohols with sulfuric acid, however, remain largely uncertain. In this talk, we present measurements of heterogeneous uptake of several carbonyls and alcohols on liquid H2SO4 in a wide range of acid concentrations and temperatures. The results indicate that uptake of larger carbonyls is explained by aldol condensation. For small dicarbonyls, heterogeneous reactions are shown to decrease with acidity and involve negligible formation of sulfate esters. Hydration and polymerization likely explain the measured uptake of such small dicarbonyls on H2SO4 and the measurements do not support an acid- catalyzed uptake. Atmospheric implications from our findings will be discussed.

Zhao, J.; Levitt, N.; Zhang, R.

2006-12-01

113

Formation of share market prices under heterogeneous beliefs and common knowledge  

NASA Astrophysics Data System (ADS)

Financial economic models often assume that investors know (or agree on) the fundamental value of the shares of the firm, easing the passage from the individual to the collective dimension of the financial system generated by the Share Exchange over time. Our model relaxes that heroic assumption of one unique "true value" and deals with the formation of share market prices through the dynamic formation of individual and social opinions (or beliefs) based upon a fundamental signal of economic performance and position of the firm, the forecast revision by heterogeneous individual investors, and their social mood or sentiment about the ongoing state of the market pricing process. Market clearing price formation is then featured by individual and group dynamics that make its collective dimension irreducible to its individual level. This dynamic holistic approach can be applied to better understand the market exuberance generated by the Share Exchange over time.

Biondi, Yuri; Giannoccolo, Pierpaolo; Galam, Serge

2012-11-01

114

Interagency report: astrogeology 55, geologic mapping of the second planet. Part 1: Rationale and general methods of lunar geologic mapping. Part 2: Technicalities of map conventions, format, production mechanics, and reviewing. Part 3: History of the US Geological Survey lunar geologic mapping program  

Microsoft Academic Search

It is shown that lunar geological mapping is similar in philosophy and principle, as well as in many details of method, to terrestrial geological mapping. Photointerpretation provides information on the structure of the whole moon and the geometric relations, areal distribution, and sequence of formation of its crystal elements.

D. E. Wilhelms

1974-01-01

115

Formation of HCN+ in Heterogeneous Reactions of N2+ and N+ with Surface Hydrocarbons  

PubMed Central

A significant increase of the ion yield at m/z 27 in collisions of low-energy ions of N2+ and N+ with hydrocarbon-covered room-temperature or heated surfaces of tungsten, carbon-fiber composite, and beryllium, not observed in analogous collisions of Ar+, is ascribed to the formation of HCN+ in heterogeneous reactions between N2+ or N+ and surface hydrocarbons. The formation of HCN+ in the reaction with N+ indicated an exothermic reaction with no activation barrier, likely to occur even at very low collision energies. In the reaction with N2+, the formation of HCN+ was observed to a different degree on these room-temperature and heated (150 and 300 °C) surfaces at incident energies above about 50 eV. This finding suggested an activation barrier or reaction endothermicity of the heterogeneous reaction of about 3–3.5 eV. The main process in N2+ or N+ interaction with the surfaces is ion neutralization; the probability of forming the reaction product HCN+ was very roughly estimated for both N2+ and N+ ions to about one in 104 collisions with the surfaces.

2013-01-01

116

Formation of HCN+ in Heterogeneous Reactions of N2+ and N+ with Surface Hydrocarbons  

NASA Astrophysics Data System (ADS)

A significant increase of the ion yield at m/z 27 in collisions of low-energy ions of N2+ and N+ with hydrocarbon-covered room-temperature or heated surfaces of tungsten, carbon-fiber composite, and beryllium, not observed in analogous collisions of Ar+, is ascribed to the formation of HCN+ in heterogeneous reactions between N2+ or N+ and surface hydrocarbons. The formation of HCN+ in the reaction with N+ indicated an exothermic reaction with no activation barrier, likely to occur even at very low collision energies. In the reaction with N2+, the formation of HCN+ was observed to a different degree on these room-temperature and heated (150 and 300 °C) surfaces at incident energies above about 50 eV. This finding suggested an activation barrier or reaction endothermicity of the heterogeneous reaction of about 3-3.5 eV. The main process in N2+ or N+ interaction with the surfaces is ion neutralization; the probability of forming the reaction product HCN+ was very roughly estimated for both N2+ and N+ ions to about one in 104 collisions with the surfaces.

Harnisch, Martina; Keim, Alan; Scheier, Paul; Herman, Zdenek

2013-10-01

117

Formation of HCN+ in Heterogeneous Reactions of N2+ and N+ with Surface Hydrocarbons.  

PubMed

Significant increase of the ion yield at m/z 27 in collisions of low-energy ions of N2+ and N+ with hydrocarbon-covered room-temperature or heated surfaces of tungsten, carbon-fiber-composite, and beryllium, not observed in analogous collisions of Ar+, is ascribed to formation of HCN+ in heterogeneous reactions between N2+ or N+ and surface hydrocarbons. The formation of HCN+ in the reaction with N+ indicated an exothermic reaction with no activation barrier, likely to occur even at very low collision energies. In the reaction with N2+, the formation of HCN+ was observed to a different degree on these room-temperature and heated (150°C and 300°C) surfaces at incident energies above about 50eV. This finding suggested an activation barrier or reaction endothermicity of the heterogeneous reaction of about 3-3.5 eV. The main process in N2+ or N+ interaction with the surfaces is ion neutralization; the probability of forming the reaction product HCN+ was very roughly estimated for both N2+ and N+ ions to about one in 104 collisions with the surfaces. PMID:23614645

Harnisch, Martina; Keim, Alan; Scheier, Paul; Herman, Zdenek

2013-04-24

118

Time-dependent transport in heterogeneous formations of bimodal structures: 1. The model  

NASA Astrophysics Data System (ADS)

Flow of uniform mean velocity U takes place in a heterogeneous medium made up from a matrix of conductivity K0 and inclusions of a different conductivity K. The inclusions of given shape are implanted at random and independently in the medium, without overlapping. The aim of the study is to derive simple, approximate solutions of advective transport of solutes in such heterogeneous formations for arbitrary permeability ratio ? = K/K0 and inclusions volume fraction n. Transport is characterized by the spatial moments, which in turn are equal to the one particle trajectory statistical moments for ergodic plumes. The flow and transport problems are solved for isotropic media, for circular (2D) and spherical (3D) inclusions by using the model of composite inclusions of Hashin and Shtrikman [1962]. The results tend to the dilute limit analyzed in the past by Eames and Bush [1999] for n = o(1). Asymptotic, analytical results are derived for weak heterogeneity (? ? 1); they coincide with those of Rubin [1995] for a similar structure. Similarly, simple asymptotic expressions of the macrodispersivity are derived for low-permeability inclusions, ? = o(1). The theoretical developments are applied to effectively computing trajectories moments in part 2 [Fiori and Dagan, 2003].

Dagan, G.; Fiori, A.

2003-05-01

119

Geology and geochemistry of the La Luna Formation type sections in the Maracaibo basin, Venezuela  

SciTech Connect

The Upper Cretaceous La Luna Formation is the most important source rock of hydrocarbons in Western Venezuela. Curiously enough it has two type sections, the formation was first defined in 1926 in Perija on the western flank of the Maracaibo basin; 30 years later the La Aguada, Chejende and Timbetes members were defined 260 km toward the east, on the shelf of the basin. The purpose of this study is to compare these sections and to define the vertical and horizontal variability of geological and geochemical characteristics that might have influenced the generation of hydrocarbons. The study consisted of detailed, bed level sampling, macroscopic sedimentary descriptions, petrography of 168 thin sections with 40 variables recorded in a statistical data matrix for determination of lithomicrofacies, as well as geochemical analysis of total organic carbon (TOC), visual kerogen, Rock-Eval pyrolysis and gas chromatography. The western type section is characterized by alternating thinly laminated and massive bedded limestones. Thermally immature, amorphous organic matter of marine origin is abundant in this section; TOC values range from 0.23% to 8.56%, generally increasing toward the top. Hydrogen index values range from 327 to 1078, indicating good to excellent oil generating potential. The eastern type sections have a higher level of thermal maturity; they show increasing amounts of clastic material, less authigenic minerals and abundant Favreina sp crab fecal pellets. The mainly terrestrially derived organic matter concentrations are considerably less, ranging from 0.07 to 3.39, again increasing toward the top of the section.

Baptista, N.; Scherer, W. [Logoven, S.A., Tamare, and Intevep, S.A., Los Teques (Venezuela)

1996-08-01

120

Microbial diversity at iron-clay interfaces after 10 years of interaction inside a deep argillite geological formation (Tournemire, France)  

Microsoft Academic Search

In the context of a geological disposal of radioactive waste in clayey formations, the consequences of microbial activity are of concern regarding the corrosion of metallic components. The purpose of the present work was to characterise the microbial diversity that may have impacted corrosion processes at the interface between re-compacted argillite and steel coupons after 10 years of interaction inside the

Laurent Urios; François Marsal; Delphine Pellegrini; Michel Magot

2012-01-01

121

Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations. Volume 5. Baseline Rock Properties-Granite.  

National Technical Information Service (NTIS)

This volume, Y/OWI/TM-36/5, Baseline Rock Properties--Granite, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental ...

1978-01-01

122

Geophysical investigation for the evaluation of the long-time safety of repositories and underground disposals in deep geological formations  

Microsoft Academic Search

The performance assessment of underground disposal facilities is an indispensable premise to ensure that repositories fulfil the requirements for permanent and safe disposal of hazardous waste. The geological barrier is supposed to be a virtually impermeable host formation like rock salt. The efficiency of the barrier is endangered by the presence of risk zones such as faults or fractures particularly

A. Just

2003-01-01

123

Effects of pore-scale dispersion, degree of heterogeneity, sampling size, and source volume on the concentration moments of conservative solutes in heterogeneous formations  

NASA Astrophysics Data System (ADS)

Pore-scale dispersion (PSD), aquifer heterogeneity, sampling volume, and source size influence solute concentrations of conservative tracers transported in heterogeneous porous formations. In this work, we developed a new set of analytical solutions for the concentration ensemble mean, variance, and coefficient of variation (CV), which consider the effects of all these factors. We developed these models as generalizations of the first-order solutions in the log-conductivity variance of point concentration proposed by [Fiori A, Dagan G. Concentration fluctuations in aquifer transport: a rigorous first-order solution and applications. J Contam Hydrol 2000;45(1-2):139-163]. Our first-order solutions compare well with numerical simulations for small and moderate formation heterogeneity and from small to large sampling and source volumes. However, their performance deteriorates for highly heterogeneous formations. Successively, we used our models to study the interplay among sampler size, source volume, and PSD. Our analysis shows a complex and important interaction among these factors. Additionally, we show that the relative importance of these factors is also a function of plume age, of aquifer heterogeneity, and of the measurement location with respect to the mean plume center of gravity. We found that the concentration moments are chiefly controlled by the sampling volume with pore-scale dispersion playing a minor role at short times and for small source volumes. However, the effect of the source volume cannot be neglected when it is larger than the sampling volume. A different behavior occurs for long periods, which may be relevant for old contaminations, or for small injection volumes. In these cases, PSD causes a significant dilution, which is reflected in the concentration statistics. Additionally, at the center of the mean plume, where high concentrations are most likely to occur, we found that sampling volume and PSD are attenuating mechanisms for both concentration ensemble mean and coefficient of variation, except at very large source and sampler sizes, where the coefficient of variation increases with sampler size and PSD. Formation heterogeneity causes a faster reduction of the ensemble mean concentrations and a larger uncertainty at the center of the mean plume. Therefore, our results highlight the importance of considering the combined effect of formation heterogeneity, exposure volume, PSD, source size, and measurement location in performing risk assessment.

Tonina, Daniele; Bellin, Alberto

2008-02-01

124

Distinct tissue formation by heterogeneous printing of osteo- and endothelial progenitor cells.  

PubMed

The organ- or tissue-printing approach, based on layered deposition of cell-laden hydrogels, is a new technique in regenerative medicine suitable to investigate whether mimicking the anatomical organization of cells, matrix, and bioactive molecules is necessary for obtaining or improving functional engineered tissues. Currently, data on performance of multicellular printed constructs in vivo are limited. In this study we illustrate the ability of the system to print intricate porous constructs containing two different cell types--endothelial progenitors and multipotent stromal cells--and show that these grafts retain heterogeneous cell organization after subcutaneous implantation in immunodeficient mice. We demonstrate that cell differentiation leading to the expected tissue formation occurs at the site of the deposited progenitor cell type. While perfused blood vessels are formed in the endothelial progenitor cell-laden part of the constructs, bone formation is taking place in the multipotent stromal cell-laden part of the printed grafts. PMID:21513466

Fedorovich, Natalja E; Wijnberg, Hans M; Dhert, Wouter J A; Alblas, Jacqueline

2011-06-08

125

Heterogeneous formation of polar stratospheric clouds - Part 1: Nucleation of nitric acid trihydrate (NAT)  

NASA Astrophysics Data System (ADS)

Satellite based observations during the Arctic winter of 2009/2010 provide firm evidence that, in contrast to the current understanding, the nucleation of nitric acid trihydrate (NAT) in the polar stratosphere does not only occur on preexisting ice particles. In order to explain the NAT clouds observed over the Arctic in mid December 2009, a heterogeneous nucleation mechanism is required, occurring via immersion freezing on the surface of solid particles, likely of meteoritic origin. For the first time, a detailed microphysical modelling of this NAT formation pathway has been carried out. Heterogeneous NAT formation was calculated along more than sixty thousand trajectories, ending at Cloud Aerosol Lidar with Orthogonal Polarisation (CALIOP) observation points. Comparing the optical properties of the modelled NAT with these observations enabled the thorough validation of a newly developed NAT nucleation parameterisation, which has been built into the Zurich Optical and Microphysical box Model (ZOMM). The parameterisation is based on active site theory, is simple to implement in models and provides substantial advantages over previous approaches which involved a constant rate of NAT nucleation in a given volume of air. It is shown that the new method is capable of reproducing observed PSCs very well, despite the varied conditions experienced by air parcels travelling along the different trajectories. In a companion paper, ZOMM is applied to a later period of the winter, when ice PSCs are also present, and it is shown that the observed PSCs are also represented extremely well under these conditions.

Hoyle, C. R.; Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Grooß, J.-U.; Peter, T.

2013-03-01

126

Contrasting the impact of aerosols at northern and southern midlatitudes on heterogeneous ice formation  

NASA Astrophysics Data System (ADS)

Three cloud data sets, each covering four months of observations, were recently recorded with a lidar at Punta Arenas (53°S), Chile, at Stellenbosch (34°S, near Cape Town), South Africa, and aboard the research vessel Polarstern during three north-south cruises. By comparing these observations with an 11-year cloud data set measured with a lidar at Leipzig (51°N), Germany, the occurrence of heterogeneous ice formation (as a function of cloud top temperature) for very different aerosol conditions in the northern and southern hemisphere is investigated. Large differences in the heterogeneous freezing behavior in the mostly layered clouds are found. For example, <20%, 30%-40% and around 70% of the cloud layers with cloud top temperatures from -15°C to -20°C, showed ice formation over Punta Arenas, Stellenbosch, and Leipzig, respectively. The observed strong contrast reflects the differences in the free tropospheric aerosol conditions at northern midlatitudes, that are controlled by anthropogenic pollution, mineral dust, forest fire smoke, terrestrial biological material and high southern midlatitudes with clean marine conditions.

Kanitz, T.; Seifert, P.; Ansmann, A.; Engelmann, R.; Althausen, D.; Casiccia, C.; Rohwer, E. G.

2011-09-01

127

Heterogeneous formation of polar stratospheric clouds - Part 1: Nucleation of nitric acid trihydrate (NAT)  

NASA Astrophysics Data System (ADS)

Satellite-based observations during the Arctic winter of 2009/2010 provide firm evidence that, in contrast to the current understanding, the nucleation of nitric acid trihydrate (NAT) in the polar stratosphere does not only occur on preexisting ice particles. In order to explain the NAT clouds observed over the Arctic in mid-December 2009, a heterogeneous nucleation mechanism is required, occurring via immersion freezing on the surface of solid particles, likely of meteoritic origin. For the first time, a detailed microphysical modelling of this NAT formation pathway has been carried out. Heterogeneous NAT formation was calculated along more than sixty thousand trajectories, ending at Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) observation points. Comparing the optical properties of the modelled NAT with these observations enabled a thorough validation of a newly developed NAT nucleation parameterisation, which has been built into the Zurich Optical and Microphysical box Model (ZOMM). The parameterisation is based on active site theory, is simple to implement in models and provides substantial advantages over previous approaches which involved a constant rate of NAT nucleation in a given volume of air. It is shown that the new method is capable of reproducing observed polar stratospheric clouds (PSCs) very well, despite the varied conditions experienced by air parcels travelling along the different trajectories. In a companion paper, ZOMM is applied to a later period of the winter, when ice PSCs are also present, and it is shown that the observed PSCs are also represented extremely well under these conditions.

Hoyle, C. R.; Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Grooß, J.-U.; Peter, T.

2013-09-01

128

Geology of the Molina Member of the Wasatch Formation, Piceance Basin, Colorado  

SciTech Connect

The Molina Member of the Wasatch Formation has been cored in order to assess the presence/absence and character of microbial communities in the deep subsurface. Geological study of the Molina Member was undertaken in support of the microbiological tasks of this project, for the purposes of characterizing the host strata and of assessing the potential for post-depositional introduction of microbes into the strata. The Molina Member comprises a sandy fluvial unit within a formation dominated by mudstones. Sandy to conglomeratic deposits of braided and meandering fluvial systems are present on the western and eastern margins of the basin respectively, although the physical and temporal equivalence of these systems cannot be proven. Distal braided facies of planar-horizontal bedded sandstones are recognized on the western margin of the basin. Natural fractures are present in all Molina sandstones, commonly as apparent shear pairs. Core from the 1-M-18 well contains natural fractures similar to those found in outcrops, and has sedimentological affinities to the meandering systems of the eastern margin of the basin. The hydrologic framework of the Molina, and thus any potential post-depositional introduction of microbes into the formation, should have been controlled by approximately east-west flow through the natural fracture system, the geometries and extent of the sandstones in which the fractures occur, and hydraulic gradient. Migration to the well site, from outcropping recharge areas at the edge of the basin, could have started as early as 40 million years ago if the cored strata are connected to the eastern sedimentary system.

Lorenz, J. [Sandia National Labs., Albuquerque, NM (United States); Nadon, G. [Ohio Univ., Athens, OH (United States); LaFreniere, L. [FD Services Inc., Casper, WY (United States)

1996-06-01

129

Influence of Aerosol Chemical Composition on Heterogeneous Ice Formation under Mid-Upper Troposphere Conditions  

NASA Astrophysics Data System (ADS)

Aerosols are involved in cooling/warming the atmosphere directly via interaction with incoming solar radiation (aerosol direct effect), or via their ability to act as cloud condensation or ice nuclei (IN) and thus play a role in cloud formation (indirect effect). In particular, the physical properties of aerosols such as size and solubility and chemical composition can influence their behavior and fate in the atmosphere. Ice nucleation taking place via IN is termed as heterogeneous ice nucleation and can take place with via deposition (ice forming on IN directly from the vapor phase), condensation/immersion (freezing via formation of the liquid phase on IN) or condensation (IN colliding with supercooled liquid drops). This presentation shows how the chemical composition and surface area of various tropospherically relevant aerosols influence conditions of temperature (T) and relative humidity (RH) required for heterogeneous ice formation conditions in the mid-upper troposphere regime (253 - 220K)? Motivation for this comes first from, the importance of being able to predict ice formation accurately so as to understand the hydrological cycle since the ice is the primary initiator of precipitation forming clouds. Second, the tropospheric budget of water vapour, an especially active greenhouse gas is strongly influenced by ice nucleation and growth. Third, ice surfaces in the atmosphere act as heterogeneous surfaces for chemical reactions of trace gases (e.g., SO2, O3, NOx and therefore being able to accurately estimate ice formation rates and quantify ice surface concentrations will allow a more accurate calculation of trace gas budgets in the troposphere. Ice nucleation measurements were conducted using a self-developed continuous flow diffusion chamber and static chamber. A number of tropospherically relevant particulates with naturally-varying and laboratory-modified surface chemistry/structure were investigated for their ice formation efficiency based on highest T and lowest RH required for ice formation. The particles investigated were classified into three categories, mineral dust aerosols, hygroscopic and non-hygroscopic particles which included organic and inorganic salts and/or coatings. In addition results ice formation results from ozone aged mineral particles will be presented. It is observed that changing functional groups on the surface of the particles can inhibit ice formation in the deposition mode. The ice forming efficiency of mineral aerosols was observed to be the highest, requiring RH with respect to ice as low as 105% at 233 K. Hydrophobic particles were comparatively weaker at forming ice and required RH close to or above water saturation for ice formation via deposition/condensation mode freezing. The high ice nucleation activity of mineral aerosols suggest that they could play an important role in ice forming and therefore precipitation processes in the troposphere and may have in impact on global and regional climate.

Kanji, Z. A.; Niemand, M.; Saathoff, H.; Möhler, O.; Chou, C.; Abbatt, J.; Stetzer, O.

2011-12-01

130

Petrophysical properties and geology of selected intervals in the Frio Formation, Stratton field, South Texas for modeling interwell seismic logging response  

SciTech Connect

Seismic or continuity logging consists of locating a seismic source in one borehole near or in a low-velocity layer and deploying a detector array in a second borehole. Detection of guided waves transmitted between the two wells indicates bed connectivity. The guided wave signatures are either leaky modes or normal modes (or both). The technique has numerous applications in various types of heterogeneous geological environments, including many Gulf Coast gas reservoirs. It can be used to determine the continuity of beds between wells, estimate and locate variations in the thickness of beds, and estimate the average rock physical properties of the beds. Stratton field was selected as the Gulf-Coast-gas-play type field for a project to model interwell seismic logging responses. Stratton is a mature gas field located in the south Texas Gulf Coast, about 30 miles southwest of Corpus Christi. It encompasses over 120,000 acres in portions of Kleberg, Nueces, and Jim Wells counties. Stratton is one of 29 fields in the Frio Formation fluvial-deltaic lay associated with the Vicksburg fault zone along the Texas Gulf Coast Basin. This poster presentation explains the technique of interwell seismic logging, documents the petrophysical properties and geology of intervals in the upper and middle Frio, and presents the results of the forward modeling tests.

Collier, H.A. [Tarleton State Univ., Stephenville, TX (United States); Parra, J.O. [Southwest Research Inst., San Antonio, TX (United States)

1996-09-01

131

Geologic control of jet formation on Comet 103P/Hartley 2  

NASA Astrophysics Data System (ADS)

The EPOXI mission flyby of Comet 103P/Hartley 2 revealed numerous discrete dust jets extending from the nucleus, thereby providing an unprecedented opportunity to visually connect these features to the nuclear surface. The observed distribution of jets yields fresh insight into the conditions under which these cometary features may form. This study examines the geomorphology associated with areas of jet activity and then applies observed topographic correlations in the construction of a 2-D hydrodynamic model of a single dust jet. Visible light images of Hartley 2 show correlations between specific surface structures with both narrow-angle and fan-shaped dust jets; associations include pits, arcuate depressions, scarps, and rimless depressions. Notably, many source regions for jets appear finer than the practical mapping resolution of the imaging instruments (˜12 m). This observation indicates that the processes controlling jet formation operate at significantly finer scales than the resolution of most cometary activity models and motivates a complementary numerical investigation of dust jet formation and evolution. In order to assess controlling variables, our parametric numerical study incorporates different geometries and volatile abundances for the observed source regions. Results indicate that the expression of jet activity not only depends on local topography but also contributes to the evolution and development of surface features. Heterogeneous distributions of volatiles within the nucleus also may contribute to differences in local styles of jet activity.

Bruck Syal, Megan; Schultz, Peter H.; Sunshine, Jessica M.; A'Hearn, Michael F.; Farnham, Tony L.; Dearborn, David S. P.

2013-02-01

132

Process and device for injecting a liquid agent used for treating a geological formation in the vicinity of a well bore traversing this formation  

SciTech Connect

A technique is disclosed for liquid treating a geological formation. It comprises spraying the liquid with a pressurized carrier gas, using a spraying pipe whose length and diameter are adjusted as a function of the pressure prevailing at the level of the formation and of the characteristics of the injected liquid and the pressurized carrier gas, so that the size of the liquid droplets at the outlet of the spraying pipe has a narrow range of distribution about a single preselected value.

Colonna, J.; Fitremann, Jm.; Genin, R.; Sarda, Jp.

1984-02-14

133

Modeling reservoir heterogeneity within outer ramp carbonate facies using an outcrop analog, San Andres Formation of the Permian Basin  

SciTech Connect

Variably cyclic, fusulinid-rich, outer ramp facies of the Permian San Andres Formation are exposed along the Algerita escarpment, Guadalupe Mountains, New Mexico. We have used the outcrop exposures and cored wells drilled adjacent to the outcrop to assess reservoir- and interwell-scale variability of permeability as a potential analog for carbonate reservoirs in the Permian basin and elsewhere. Permeability distribution was evaluated using a field permeameter and conventional measurements on small core plugs taken along vertical and horizontal outcrop traverses and from the slim-hole cores. Geostatistical models of permeability variation, honoring the geologic and petrophysical data, were constructed and input into a waterflood simulator to understand the interactions between heterogeneity and flow. Different vertical variogram characteristics are displayed by cyclic and less distinctly cyclic parts of the San Andres. Variograms constructed for horizontal transect data from three distinct stratigraphic units have nearly identical properties. Overall, the ranges of correlation are short (3-3.5 in; 10-12 ft) when compared to typical interwell distances, supporting a nearly uncorrelated and highly variable permeability model. Using observed short ranges of vertical and horizontal correlation and honoring the vertical transect data, cross sectional, conditionally simulated permeability fields were generated and used in simulated waterfloods to investigate the sensitivities to an oil recovery model and overall fluid injection rate for this style of stratigraphy and cyclicity. Cyclic parts of the section are characterized by a potential for early water breakthrough and relatively high vertical sweep efficiencies. Within the less distinctly cyclic section, waterflood fronts have a fingerlike profile and vertical sweep efficiency is generally poorer.

Eisenberg, R.A.; Harris, P.M.; Grant, C.W. [Chevron Petroleum Technology Co., La Habra, CA (United States)] [and others

1994-09-01

134

Formation of Small Gas Phase Carbonyls from Heterogeneous Oxidation of Polyunsaturated Fatty Acids (PUFA)  

NASA Astrophysics Data System (ADS)

Fatty acids (FAs) are emitted into the atmosphere from gas and diesel powered vehicles, cooking, plants, and marine biota. Field measurements have suggested that FAs, including polyunsaturated fatty acids (PUFA), could make up an important contribution to the organic fraction of atmospheric aerosols. Due to the existence of carbon-carbon double bonds in their molecules, PUFA are believed to be highly reactive towards atmospheric oxidants such as OH and NO3 radicals and ozone, which will contribute to aerosol hygroscopicity and cloud condensation nuclei activity. Previous work from our group has shown that small carbonyls formed from the heterogeneous reaction of linoleic acid (LA) thin films with gas-phase O3. It is known that the formation of small carbonyls in the atmosphere is not only relevant to the atmospheric budget of volatile organic compounds but also to secondary organic aerosol formation. In the present study, using an online proton transfer reaction mass spectrometry (PTR-MS) and off-line gas chromatography-mass spectrometry (GC-MS) we again investigated carbonyl formation from the same reaction system, i.e. the heterogeneous ozonolysis of LA film. In addition to the previously reported carbonyls, malondialdehyde (MDA), a source of reactive oxygen species that is mutagenic, has been identified as a product for the first time. Small dicarbonyls, e.g. glyoxal, are expected to be formed from the further oxidation of MDA. In this presentation, the gas-phase chemistry of MDA with OH radicals using a newly built Teflon chamber in our group will also be presented.

Zhou, S.; Zhao, R.; Lee, A.; Gao, S.; Abbatt, J.

2011-12-01

135

Mantle heterogeneity under spreading zones of polar regions of the Atlantic Ocean: sources and formation  

NASA Astrophysics Data System (ADS)

A number of provinces with prevailing distribution of enriched rift basalts are specified within spreading zones of Indo-Atlantic segment of the World Ocean. The main reason of EMORB-type melts formation is determined by source heterogeneity which is resulted in numerous causes: recycling of old oceanic crust, hotspots within immediate proximity to rift zone, formation of metasomtizated mantle at the early stage of ocean opening which is involved in melting process later on. The spatial distribution of enriched tholeiites within Polar Atlantic is confined by Knipovich, Kolbeinsey and Gakkel ridges. The Knipovich ridge spreading zone formation coincides in time with magmatism appearances in adjacent continental regions. Comparative studying of Neogene and Quaternary magmatism of the Svalbard Island and modern magmatism of the Knipovich ridge reveals pyroxenite mantle participation in the melting process. The main source for Neogene magmas of the Svalbard Island was olivine-free pyroxenite with high 87Sr/86Sr and lower 143Nd/144Nd ratios, which could be a result of interaction of recycled substance of old oceanic crust and low continental crust with mantle peridotite. Due to its preferential fusibility this pyroxenite could be the source for substantial magmas volume under the rigid continental lithosphere that subsequently could have caused its disintegration. With successive rejuvenation of Svaldbard and Knipovich ridge magmatism (from Neogene till nowadays) for its mantle sources there has been traced the decreasing of pyroxenite component share at the expense of increasing of peridotite share accompanied by regular change of Sr and Nd isotope composition of these sources. The old Antarctic continent played a pivot role in the South Ocean formation, geodynamics and magmatism of trap formations and rift zones. The area of Karoo-Maud plume distribution at the early stages (about 180 - 170 Ma) included the southeastern part of Africa and the west of East Antarctic and nowadays it occupies the area of Bouvet hotspot modern location. Development of Karoo-Maud plume caused the formation of considerable mantle heterogeneity and contributed to disintegration of continental blocks within the forming South Ocean. Magmatism of the formed spreading basins of the western Antarctic (Powell and Bransfield) is characterized by greater range of enrichment and evidence to possible melting of pyroxenites which represented the fragments of low parts of continental lithosphere involved into the melting process at mantle asthenospheric upwelling in spreading zones. This component is close by its isotope characteristics to a component revealed within the western edge of Southwest Indian Ridge near the Bouvet triple junction and is represented by a mixture of sources like HIMU and EM-2.

Sushchevskaya, N. M.; Belyatsky, B. V.; Dubinin, E. P.

2012-04-01

136

Microbial characterization of basalt formation waters targeted for geological carbon sequestration.  

PubMed

Geological carbon sequestration in basalts is a promising solution to mitigate carbon emissions into the Earth's atmosphere. The Wallula pilot well in Eastern Washington State, USA provides an opportunity to investigate how native microbial communities in basalts are affected by the injection of supercritical carbon dioxide into deep, alkaline formation waters of the Columbia River Basalt Group. Our objective was to characterize the microbial communities at five depth intervals in the Wallula pilot well prior to CO2 injection to establish a baseline community for comparison after the CO2 is injected. Microbial communities were examined using quantitative polymerase chain reaction to enumerate bacterial cells and 454 pyrosequencing to compare and contrast the diversity of the native microbial communities. The deepest depth sampled contained the greatest amount of bacterial biomass, as well as the highest bacterial diversity. The shallowest depth sampled harbored the greatest archaeal diversity. Pyrosequencing revealed the well to be dominated by the Proteobacteria, Firmicutes, and Actinobacteria, with microorganisms related to hydrogen oxidizers (Hydrogenophaga), methylotrophs (Methylotenera), methanotrophs (Methylomonas), iron reducers (Geoalkalibacter), sulfur oxidizers (Thiovirga), and methanogens (Methermicocccus). Thus, the Wallula pilot well is composed of a unique microbial community in which hydrogen and single-carbon compounds may play a significant role in sustaining the deep biosphere. PMID:23418786

Lavalleur, Heather J; Colwell, Frederick S

2013-03-18

137

Geological factors controlling the utility of refractory dolomite: The Cambrian Ledger Formation dolomite, a case study  

SciTech Connect

The Middle Cambrian Ledger Formation in eastern Pennsylvania is a high purity, single-stage-sintering dolomite. It yields high quality, direct bonded, environmentally clean, doloma bricks for steel, cement and lime industries use. Geological properties are controlled by the depositional environment, diagenesis, metamorphism, deformation, and rifting. The Middle Cambrian was a time of high sea level stand, high evaporation, low volcanism, and absence of land plants. This produced carbonates low in SiO[sub 2], Al[sub 2]O[sub 3], and Fe[sub 2]O[sub 3] (< 1%). Uniform oolite shoals developed on fault blocks. Early diagenesis dolomitized the [approx]1 mm oolites. The Taconic-Acadian Orogeny greenschist-metamorphism annealed the dolomite by heating it to 300--400 C, at [approx]2 kbar, for [approx]200 million years. This produced a homogeneous coarse crystalline, nonporous, nonplanar dolomite with uniform grain chemistry. Alleghenian overthrusting strained the dolomite, producing deformed oolite ghosts, and minor strain twins. Time, temperature, pressure, and strain increases sinterability and thus suitability of the dolomite for refractory purposes. Near Triassic faults the quality of the brickstone grade dolomite has been degraded to fettling and agricultural grade dolomite. Faulting produced dolomite twinning, polymictic brecciation, and fracture porosity. Karstification generated quartz, feldspar and hematite that filled the porosity. Triassic intrusions partial recrystallized the dolomite incorporating the impurities and thereby degrading it.

Furman, F.C.; Gregg, J.M.; Ablin, V.C.; Moore, R.E. (Univ. of Missouri, Rolla, MO (United States))

1993-03-01

138

Nuclear Waste Disposal in Deep Geological Formations: What are the Major Remaining Scientific Issues?  

SciTech Connect

For more than thirty years, considerable efforts have been carried out in order to evaluate the possibility of disposing of high level wastes in deep geological formations. Different rock types have been examined, such as water-under-saturated tuffs (USA), granites or crystalline rocks (Canada, Sweden, and Finland), clays (France, Belgium, and Switzerland), rock-salt (Germany). Deep clays and granites, (provided that the most fractured zones are avoided in the second case) are considered to fulfill most allocated functions, either on short term (reversibility) or long term. Chemically reducing conditions favor the immobilization of actinides and most fission products by precipitation, co-precipitation and sorption. If oxidizing conditions prevail, the safety demonstration will mostly rely on the performance of artificial confinement systems. Rock-salt offers limited performance considering the issue of reversibility, which is now perceived as essential, mostly for ethical and sociological reasons. However, several issues would deserve additional research programs, and as a first priority, a clear description of time/space succession of processes during the evolution of the repository. This will allow a better representation of coupled processes in performance assessment, such as the influence of gases (H{sub 2}) generated by corrosion, on the long term dynamics of the re-saturation. Geochemical interactions between the host formation and the engineered systems (packages + barriers) are still insufficiently described. Additional gains in performance could be obtained when taking into account processes such as isotopic exchange. Imaginative solutions, employing ceramic- carbon composite materials could be proposed to replace heavy and gas-generating overpacks, or to accommodate the small but probably significant amount of 'ultimate' wastes that will be inevitably produced by Generation IV reactor systems. (author)

Toulhoat, Pierre [Institut des Sciences Analytiques, Universite de Lyon, 43 avenue du 11 novembre 1918, Villeurbanne, 69622 (France); Scientific Direction, INERIS, Parc Technologique ALATA, BP2, Verneuil-en-Halatte, 60550, (France)

2007-07-01

139

Mercury's hollows: Constraints on formation and composition from analysis of geological setting and spectral reflectance  

NASA Astrophysics Data System (ADS)

unique to Mercury, hollows are shallow, flat-floored irregular depressions notable for their relatively high reflectance and characteristic color. Here we document the range of geological settings in which hollows occur. Most are associated with impact structures (simple bowl-shaped craters to multiring basins, and ranging from Kuiperian to Calorian in age). Hollows are found in the low-reflectance material global color unit and in low-reflectance blue plains, but they appear to be absent from high-reflectance red plains. Hollows may occur preferentially on equator- or hot-pole-facing slopes, implying that their formation is linked to solar heating. Evidence suggests that hollows form because of loss of volatile material. We describe hypotheses for the origin of the volatiles and for how such loss proceeds. Intense space weathering and solar heating are likely contributors to the loss of volatiles; contact heating by melts could promote the formation of hollows in some locations. Lunar Ina-type depressions differ from hollows on Mercury in a number of characteristics, so it is unclear if they represent a good analog. We also use MESSENGER multispectral images to characterize a variety of surfaces on Mercury, including hollows, within a framework defined by laboratory spectra for analog minerals and lunar samples. Data from MESSENGER's X-Ray Spectrometer indicate that the planet's surface contains up to 4% sulfur. We conclude that nanophase or microphase sulfide minerals could contribute to the low reflectance of the low-reflectance material relative to average surface material. Hollows may owe their relatively high reflectance to destruction of the darkening agent (sulfides), the presence of alteration minerals, and/or physical differences in particle size, texture, or scattering behavior.

Blewett, David T.; Vaughan, William M.; Xiao, Zhiyong; Chabot, Nancy L.; Denevi, Brett W.; Ernst, Carolyn M.; Helbert, JöRn; D'Amore, Mario; Maturilli, Alessandro; Head, James W.; Solomon, Sean C.

2013-05-01

140

Source/Sink Matching for U.S. Ethanol Plants and Candidate Deep Geologic Carbon Dioxide Storage Formations  

SciTech Connect

This report presents data on the 140 existing and 74 planned ethanol production facilities and their proximity to candidate deep geologic storage formations. Half of the existing ethanol plants and 64% of the planned units sit directly atop a candidate geologic storage reservoir. While 70% of the existing and 97% of the planned units are within 100 miles of at least one candidate deep geologic storage reservoir. As a percent of the total CO2 emissions from these facilities, 92% of the exiting units CO2 and 97% of the planned units CO2 emissions are accounted for by facilities that are within 100 miles of at least one potential CO2 storage reservoir.

Dahowski, Robert T.; Dooley, James J.

2008-09-18

141

Travel time approach to kinetically sorbing solute by diverging radial flows through heterogeneous porous formations  

NASA Astrophysics Data System (ADS)

Diverging radial flow takes place in a heterogeneous porous medium where the log conductivity Y = ln K is modeled as a stationary random space function (RSF). The flow is steady, and is generated by a fully penetrating well. A linearly sorbing solute is injected through the well envelope, and we aim at computing the average flux concentration (breakthrough curve). A relatively simple solution for this difficult problem is achieved by adopting, similar to Indelman and Dagan (1999), a few simplifying assumptions: (i) a thick aquifer of large horizontal extent, (ii) mildly heterogeneous medium, (iii) strongly anisotropic formation, and (iv) large Peclet number. By introducing an appropriate Lagrangian framework, three-dimensional transport is mapped onto a one-dimensional domain (?, t) where ? and t represent the fluid travel and current time, respectively. Central for this approach is the probability density function of the RSF ?that is derived consistently with the adopted assumptions stated above. Based on this, it is shown that the travel time can be regarded as a Gaussian random variable only in the far field. The breakthrough curves are analyzed to assess the impact of the hydraulic as well as reactive parameters. Finally, the travel time approach is tested against a forced-gradient transport experiment and shows good agreement.

Severino, Gerardo; de Bartolo, Samuele; Toraldo, Gerardo; Srinivasan, Gowri; Viswanathan, Hari

2012-12-01

142

Numerical simulations of solute transport in highly heterogeneous formations: A comparison of alternative numerical schemes  

NASA Astrophysics Data System (ADS)

We compare the accuracy of five numerical schemes in modeling transport of nonreactive and reactive solutes in porous formations with heterogeneity increasing from low (?Y2=0.2) to very high (?Y2=10). Two schemes, the Total Variation Diminishing (TVD) and the Eulerian-Lagrangian Method of Characteristics (MOC), are available in widely used packages. The other three schemes are the Random Walk Particle Tracking (RWPT), the Smoothed Particle Hydrodynamics (SPH) and a Streamline-Based (SB-FV) method, which we modified to improve its accuracy. The advective nature of the transport problem renders the numerical solution very challenging with the solutions provided by classic Eulerian methods that are plagued by numerical diffusion and spurious oscillations. Our analysis shows that TVD is severely affected by numerical diffusion, while the modified SB-FV method shows the tendency to underestimate dilution to an extent that increases with ?Y2. In addition, we show that MOC is not mass-conservative, SPH is computationally demanding and cannot handle anisotropic dispersion, while RWPT develops spurious concentration fluctuations, which can be attenuated by increasing the number of particles at the expenses of an increase of the CPU time. Moreover, we investigate the effect of uniform and non-uniform local dispersion models on the overall plume dilution. These results help to consciously choose the numerical scheme according to investigation's objectives and heterogeneity degree.

Boso, Francesca; Bellin, Alberto; Dumbser, Michael

2013-02-01

143

The Oil Game: Problem-based learning exercise in an Environmental Geology lecture-format class  

NSDL National Science Digital Library

This is an active engagement exercise as a capstone exercise in a unit on energy in an Environmental Geology class of non-science majors combining a 'field-based' simulation and 'office-based' geological modeling. It uses readily available supplies and easily constructed equipment that can take 1 or 2 class meetings.

Voorhees, David

144

Domain formation in membranes with quenched protein obstacles: Lateral heterogeneity and the connection to universality classes  

NASA Astrophysics Data System (ADS)

We show that lateral fluidity in membranes containing quenched protein obstacles belongs to the universality class of the two-dimensional random-field Ising model. The main feature of this class is the absence of a phase transition: there is no critical point and macroscopic domain formation does not occur. Instead there is only one phase. This phase is highly heterogeneous with a structure consisting of microdomains. The presence of quenched protein obstacles thus provides a mechanism to stabilize lipid rafts in equilibrium. Crucial for two-dimensional random-field Ising universality is that the obstacles are randomly distributed and have a preferred affinity to one of the lipid species. When these conditions are not met standard Ising or diluted Ising universality applies. In these cases a critical point does exist which then marks the onset toward macroscopic demixing.

Fischer, T.; Vink, R. L. C.

2011-02-01

145

Flow and transport in highly heterogeneous formations: 3. Numerical simulations and comparison with theoretical results  

NASA Astrophysics Data System (ADS)

In parts 1 [, 2003] and 2 [, 2003] a multi-indicator model of heterogeneous formations is devised in order to solve flow and transport in highly heterogeneous formations. The isotropic medium is made up from circular (2-D) or spherical (3-D) inclusions of different conductivities K, submerged in a matrix of effective conductivity. This structure is different from the multi-Gaussian one, even for equal log conductivity distribution and integral scale. A snapshot of a two-dimensional plume in a highly heterogeneous medium of lognormal conductivity distribution shows that the model leads to a complex transport picture. The present study was limited, however, to investigating the statistical moments of ergodic plumes. Two approximate semianalytical solutions, based on a self-consistent model (SC) and on a first-order perturbation in the log conductivity variance (FO), are used in parts 1 and 2 in order to compute the statistical moments of flow and transport variables for a lognormal conductivity pdf. In this paper an efficient and accurate numerical procedure, based on the analytic-element method [, 1989], is used in order to validate the approximate results. The solution satisfies exactly the continuity equation and at high-accuracy the continuity of heads at inclusion boundaries. The dimensionless dependent variables depend on two parameters: the volume fraction n of inclusions in the medium and the log conductivity variance ?Y2. For inclusions of uniform radius, the largest n was 0.9 (2-D) and 0.7 (3-D), whereas the largest ?Y2 was equal to 10. The SC approximation underestimates the longitudinal Eulerian velocity variance for increasing n and increasing ?Y2 in 2-D and, to a lesser extent, in 3-D, as compared to numerical results. The FO approximation overestimates these variances, and these effects are larger in the transverse direction. The longitudinal velocity pdf is highly skewed and negative velocities are present at high ?Y2, especially in 2-D. The main results are in the comparison of the macrodispersivities, computed with the aid of the Lagrangian velocity covariances, as functions of travel time. For the longitudinal macrodispersivity, the SC approximation yields results close to the numerical ones in 2-D for n = 0.4 but underestimates them for n = 0.9. The asymptotic, large travel time values of macrodispersivities in the SC and FO approximations are close for low to moderate ?Y2, as shown and explained in part 1. However, while the slow tendency to Fickian behavior is well reproduced by SC, it is much quicker in the FO approximation. In 3-D the SC approximation is closer to numerical one for the highest n = 0.7 and the different ?Y2 = 2, 4, 8, and the comparison improves if molecular diffusion is taken into account. Transverse macrodispersivity for small travel times is underestimated by SC in 2-D and is closer to numerical results in 3-D, whereas FO overestimates them. Transverse macrodispersivity asymptotically tends to zero in 2-D for large travel times. In 3-D the numerical simulations lead to a small but persistent transverse macrodispersivity for large travel times, whereas it tends to zero in the approximate solutions. The results suggest that the self-consistent semianalytical approximation provides a valuable tool to model transport in highly heterogeneous isotropic formations of a 3-D structure in terms of trajectories statistical moments. It captures effects like slow transition to Fickian behavior and to Gaussian trajectory distribution, which are neglected by the first-order approximation.

Jankovi?, I.; Fiori, A.; Dagan, G.

2003-09-01

146

Phased Array Approach To Retrieve Gases, Liquids, Or Solids From Subsurface And Subaqueous Geologic Or Man-Made Formations  

Microsoft Academic Search

A method of enhancing the remediation of contaminated soils and ground water, production of oil and gas, and production of any solid, gas, and\\/or liquid from subsurface geologic and man-made formations including the steps of estimating the geometric boundaries of the region containing the material to be recovered, drilling a recovery well(s) into subsurface in a strategic location to recover

Timothy M. Rynne; John F. Spadaro; Joe L. Iovenitti; John P. Dering; Donald G. Hill

1998-01-01

147

Probabilistic risk assessment for CO2 storage in geological formations: robust design and support for decision making under uncertainty  

Microsoft Academic Search

CO2 storage in geological formations is currently being discussed intensively as a technology for mitigating CO2 emissions. However, any large-scale application requires a thorough analysis of the potential risks. Current numerical simulation models are too expensive for probabilistic risk analysis and for stochastic approaches based on brute-force repeated simulation. Even single deterministic simulations may require parallel high-performance computing. The multiphase

Sergey Oladyshkin; Rainer Helmig; Wolfgang Nowak

2010-01-01

148

Model of the Transfer of Dissolved Radioelements in Deep Geological Formations.  

National Technical Information Service (NTIS)

The disposal of nuclear wastes in deep geological strata presents the problem of their possible return to the human environment through natural flows of groundwater. To estimate the risks which these migration mechanisms might represent, it is necessary t...

G. de Marsily P. Goblet E. Ledoux A. Barbreau

1978-01-01

149

Upscaling of flow in heterogeneous porous formations: Critical examination and issues of principle  

NASA Astrophysics Data System (ADS)

We consider heterogeneous media whose properties vary in space and particularly aquifers whose hydraulic conductivity K may change by orders of magnitude in the same formation. Upscaling of conductivity in models of aquifer flow is needed in order to reduce the numerical burden, especially when modeling flow in heterogeneous aquifers of 3D random structure. Also, in many applications the interest is in average values of the dependent variables over scales larger or comparable to the conductivity length scales. Assigning values of the conductivity Kb to averaging domains, or computational blocks, is the topic of a large body of literature, the problem being of wide interest in various branches of physics and engineering. It is clear that upscaling causes loss of information and at best it can render a good approximation of the fine scale solution after averaging it over the blocks.The present article focuses on upscaling approaches dealing with random media. It is not meant to be a review paper, its main scope being to elucidate a few issues of principle and to briefly discuss open questions. We show that upscaling can be usually achieved only approximately, and the result may depend on the particular upscaling scheme adopted. The typically scarce information on the statistical structure of the fine-scale conductivity imposes a strong limitation to the upscaling problem. Also, local upscaling is not possible in nonuniform mean flows, for which the upscaled conductivity tensor is generally nonlocal and it depends on the domain geometry and the boundary conditions. These and other limitations are discussed, as well as other open topics deserving further investigation.

Dagan, G.; Fiori, A.; Jankovic, I.

2013-01-01

150

Heterogeneity in a Low-Permeability Formation or Non-Ideal Testing Conditions?  

NASA Astrophysics Data System (ADS)

Hydraulic testing in packer-isolated wellbore intervals in low-permeability formations is often complicated by non-ideal conditions such as thermal expansion of fluid in the test interval, packer squeeze and borehole closure. Such processes lead to fluid accumulation and pressurization within the wellbore during shut-in, and can exert significant effects on the measured borehole pressure response. Unless these conditions are taken into account during test interpretation, it is possible to make inappropriate conclusions regarding formation heterogeneity (e.g., lateral permeability variations) and/or static pressure levels. We have developed a lumped parameter modeling approach by treating the combined effect of these processes as the equivalent of an additional volume of fluid accumulating within the test interval (in addition to the nominal test-interval volume at the time of shut-in). We postulate that the rate of fluid accumulation can be treated in a simple manner as a constant value for the duration of the test. Thus, the fluid accumulation problem can be recast as the equivalent of a constant injection rate into the packed-off volume within the borehole. We show how this surrogate injection rate can be estimated from the measured pressure data by exploiting the analogy between the pressure response during borehole storage dominated conditions and that of a line-source well with an exponentially varying flow rate. Shut-in test sequences (i.e., shut-in period prior to initiation of a pressure pulse test and shut-in period(s) during pulse test(s)) can then be analyzed as effective constant-rate injection periods. The methodology is demonstrated using data from a recent series of hydraulic tests conducted in support of site characterization activities by ANDRA, the French radioactive waste management agency. In many of these tests, the measured pressure response was fitted to a 2-zone radially composite system model. Although the fit was visually excellent, static pressure estimates were found to be significantly different than those obtained from long-term pressure monitoring data from permanently installed borehole pressure gauges that use wireless telemetry for data transmission. These special tools (called EPG tools) provide the highest quality monitoring data for defining true undisturbed formation pressures in very low-permeability formations. In this study, the hydraulic-test data were reanalyzed using the lumped parameter modeling approach with a single-zone homogeneous model constrained to the static pressure bounds indicated by the EPG data. The single-zone analysis yields visual fits comparable to those from the 2-zone radially composite model, and formation parameters that are statistically much more robust (i.e., they do not suffer from over-parameterization and poor parameter identifiability as do the parameter estimates from the 2-zone conceptualization). We conclude that the effects of non-ideal testing conditions can be mistaken as indicators of formational heterogeneities.

Mishra, S.; Deeds, N. E.; Pickens, J. F.; Distinguin, M.; Delay, J.

2005-12-01

151

3rd hand smoking; heterogeneous oxidation of nicotine and secondary aerosol formation in the indoor environment  

NASA Astrophysics Data System (ADS)

Tobacco smoking is well known as a significant source of primary indoor air pollutants. However, only recently has it been recognized that the impact of Tobacco smoking may continue even after the cigarette has been extinguished (i.e., third hand smoke) due to the effect of indoor surfaces. These surfaces may affect the fate of tobacco smoke in the form of secondary reactions and pollutants, including secondary organic aerosol (SOA) formation. Fourier Transform Infrared spectrometry with Attenuated Total Reflection (FTIR-ATR) in tandem with a Scanning Mobility Particle Sizing (SMPS) system was used to monitor the ozonation of cellulose sorbed nicotine and resulting SOA formation. SOA formation began at onset of ozone introduction ([O3] = 60 ± 5 ppb) with a size distribution of dp ? 25 nm, and was determined to be a result of heterogeneous reaction (opposed to homogeneous). SOA yield from reacted surface nicotine was on the order of 10 %. Simultaneous to SOA monitoring, FTIR-ATR spectra showed surface changes in the nicotine film as the reaction progressed, revealing a pseudo first-order surface reaction rate of 0.0026 ± 0.0008 min-1. Identified surface oxidation products included: cotinine, myosmine, methylnicotinamide and nicotyrine. Surface reaction rate was found to be partially inhibited at high relative humidity. Given the toxicity of some of the identified products (e.g., cotinine has shown potential mutagenicity and teratogenicity) and that small particles may contribute to adverse health effects, the present study indicates that exposure to 3rd hand smoke ozonation products may pose additional health risks.

Petrick, Lauren; Dubowski, Yael

2010-05-01

152

Spontaneous formation of heterogeneous patches on polymer-lipid core-shell particle surfaces during self-assembly.  

PubMed

Spontaneous formation of heterogeneous patches on the surface of lipid-based nanoparticles (NPs) and microparticles (MPs) due to the segregation of two different functional groups. Patch formation is observed when tracing the functional groups with quantum dots, gold nanoparticles, and fluorescent dyes. This discovery could have important implications for the future design of self-assembled NPs and MPs for different biomedical applications. PMID:23109494

Salvador-Morales, Carolina; Valencia, Pedro M; Gao, Weiwei; Karnik, Rohit; Farokhzad, Omid C

2012-10-26

153

Capacity investigation of brine-bearing sands of the Fwwm formation for geologic sequestration of CO{sub 2}  

SciTech Connect

The capacity of fluvial brine-bearing formations to sequester CO{sub 2} is investigated using numerical simulations of CO{sub 2} injection and storage. Capacity is defined as the volume fraction of the subsurface available for CO{sub 2} storage and is conceptualized as a product of factors that account for two-phase flow and transport processes, formation geometry, formation heterogeneity, and formation porosity. The space and time domains used to define capacity must be chosen with care to obtain meaningful results, especially when comparing different authors' work. Physical factors that impact capacity include permeability anisotropy and relative permeability to CO{sub 2}, brine/CO{sub 2} density and viscosity ratios, the shape of the trapping structure, formation porosity and the presence of low-permeability layering.

Doughty, Christine; Pruess, Karsten; Benson, Sally M.; Hovorka, Susan D.; Knox, Paul R.; Green, Christopher T.

2001-05-01

154

Towards a unified framework for anomalous transport in heterogeneous media  

Microsoft Academic Search

We develop a unified framework to model the anomalous transport of tracers in highly heterogeneous media. While the framework is general, our working media in this study are geological formations. The basis of our approach takes into account the different levels of uncertainty, often associated with spatial scale, in characterizing these formations. The effects on the transport of smaller spatial

Harvey Scher; Gennady Margolin; Brian Berkowitz

2002-01-01

155

Laboratory investigations of the effects of geologic heterogeneity on groundwater salinization and flush-out times from a tsunami-like event  

NASA Astrophysics Data System (ADS)

This intermediate scale laboratory experimental study was designed to improve the conceptual understanding of aquifer flushing time associated with diffuse saltwater contamination of coastal aquifers due to a tsunami-like event. The motivation comes from field observations made after the tsunami in December, 2004 in South Asia. The focus is on the role and effects of heterogeneity on flushing effectiveness. A scheme that combines experimentation in a 4.8 m long laboratory tank and numerical modeling was used. To demonstrate the effects of geologic heterogeneity, plume migration and flushing times were analyzed in both homogeneous and layered media and under different boundary conditions (ambient flow, saltwater infiltration rate, freshwater recharge). Saltwater and freshwater infiltrations imitate the results of the groundwater salinization from the tsunami and freshening from the monsoon rainfall. The saltwater plume behavior was monitored both through visual observations (digital photography) of the dyed salt water and using measurements taken from several electrical conductivity sensors installed through the tank walls. The variable-density, three dimensional code HST3D was used to simulate the tank experiments and understand the fate and movement of the saltwater plume under field conditions. The results from the tank experiments and modeling demonstrated that macro-scale heterogeneity significantly influenced the migration patterns and flushing times of diffuse saltwater contamination. Ambient flow had a direct influence on total flush-out time, and heterogeneity impacted flush-out times for the top part of the tank and total flush-out times. The presence of a continuous low-permeability layer caused a 40% increase in complete flush-out time due to the slower flow of salt water in the low-permeability layer. When a relatively small opening was introduced in the low-permeability layer, salt water migrated quickly into a higher-permeable layer below causing a reduction in flush-out time. Freshwater recharge caused an early dilution of salt water in the top part of the tank in the case of a layered media, but also pushed the saltwater plume into the low-permeability layer which led to increased total flush-out times.

Vithanage, M.; Engesgaard, P.; Jensen, K. H.; Illangasekare, T. H.; Obeysekera, J.

2012-08-01

156

Adsorption of binary gas mixtures in heterogeneous carbon predicted by density functional theory: on the formation of adsorption azeotropes.  

PubMed

Classical density functional theory (DFT) was used to predict the adsorption of nine different binary gas mixtures in a heterogeneous BPL activated carbon with a known pore size distribution (PSD) and in single, homogeneous, slit-shaped carbon pores of different sizes. By comparing the heterogeneous results with those obtained from the ideal adsorbed solution theory and with those obtained in the homogeneous carbon, it was determined that adsorption nonideality and adsorption azeotropes are caused by the coupled effects of differences in the molecular size of the components in a gas mixture and only slight differences in the pore sizes of a heterogeneous adsorbent. For many binary gas mixtures, selectivity was found to be a strong function of pore size. As the width of a homogeneous pore increases slightly, the selectivity for two different sized adsorbates may change from being greater than unity to less than unity. This change in selectivity can be accompanied by the formation of an adsorption azeotrope when this same binary mixture is adsorbed in a heterogeneous adsorbent with a PSD, like in BPL activated carbon. These results also showed that the selectivity exhibited by a heterogeneous adsorbent can be dominated by a small number of pores that are very selective toward one of the components in the gas mixture, leading to adsorption azeotrope formation in extreme cases. PMID:20712330

Ritter, James A; Pan, Huanhua; Balbuena, Perla B

2010-09-01

157

Evaluation of the geological relationships to gas hydrate formation and stability. Second annual technical progress report, October 1, 1985--September 30, 1986.  

National Technical Information Service (NTIS)

Although there are many publications pertaining to gas hydrates, their formation and stability in various geological conditions are poorly known. Therefore, for the same reasons and because of the very broad scope of our research, limited amount and extre...

1986-01-01

158

Flow and Transport in Highly Heterogeneous Porous Formations: Numerical Experiments Performed Using the Analytic Element Method  

NASA Astrophysics Data System (ADS)

Flow and transport in porous formations are analyzed using numerical simulations. Hydraulic conductivity is treated as a spatial random function characterized by a probability density function and a two-point covariance function. Simulations are performed for a multi-indicator conductivity structure developed by Gedeon Dagan (personal communication). This conductivity structure contains inhomogeneities (inclusions) of elliptical and ellipsoidal geometry that are embedded in a homogeneous background. By varying the distribution of sizes and conductivities of inclusions, any probability density function and two-point covariance may be reproduced. The multi-indicator structure is selected since it yields simple approximate transport solutions (Aldo Fiori, personal communication) and accurate numerical solutions (based on the Analytic Element Method). The dispersion is examined for two conceptual models. Both models are based on the multi-indicator conductivity structure. The first model is designed to examine dispersion in aquifers with continuously varying conductivity. The inclusions in this model cover as much area/volume of the porous formation as possible. The second model is designed for aquifers that contain clay/sand/gravel lenses embedded in otherwise homogeneous background. The dispersion in both aquifer types is simulated numerically. Simulation results are compared to those obtained using simple approximate solutions. In order to infer transport statistics that are representative of an infinite domain using the numerical experiments, the inclusions are placed in a domain that was shaped as a large ellipse (2D) and a large spheroid (3D) that were submerged in an unbounded homogeneous medium. On a large scale, the large body of inclusions behaves like a single large inhomogeneity. The analytic solution for a uniform flow past the single inhomogeneity of such geometry yields uniform velocity inside the domain. The velocity differs from that at infinity and can be used to infer the effective conductivity of the medium. As many as 100,000 inhomogeneities are placed inside the domain for 2D simulations. Simulations in 3D were limited to 50,000 inclusions. A large number of simulations was conducted on a massively parallel supercomputer cluster at the Center for Computational Research, University at Buffalo. Simulations range from mildly heterogeneous formations to highly heterogeneous formations (variance of the logarithm of conductivity equal to 10) and from sparsely populated systems to systems where inhomogeneities cover 95% of the volume. Particles are released and tracked inside the core of constant mean velocity. Following the particle tracking, various medium, flow, and transport statistics are computed. These include: spatial moments of particle positions, probability density function of hydraulic conductivity and each component of velocity, their two-point covariance function in the direction of flow and normal to it, covariance of Lagrangean velocities, and probability density function of travel times to various break-through locations. Following the analytic nature of the flow solution, all the results are presented in dimensionless forms. For example, the dispersion coefficients are made dimensionless with respect to the mean velocity and size of inhomogeneities. Detailed results will be presented and compared to well known first-order results and the results that are based on simple approximate transport solutions of Aldo Fiori.

Jankovic, I.

2002-05-01

159

Strontium isotope tracking of groundwater-CO2 interactions in Chimayo, New Mexico, and implications for carbon storage in geologic formations  

Microsoft Academic Search

James Gardiner1, Brian Stewart1, Rosemary Capo1, J. Alexandra Hakala2 1Department of Geology and Planetary Sciences, University of Pittsburgh 2National Energy Technology Laboratory, Pittsburgh, PA The storage of carbon dioxide in geologic formations requires sensitive monitors of the geochemical and mineralogical interactions of storage units, their formation waters, and associated aquifers potentially affected by subsurface CO2. High CO2 subsurface environments can

J. Gardiner; B. W. Stewart; R. Capo; J. Hakala

2009-01-01

160

Atmospheric secondary aerosol formation by heterogeneous reactions of aldehydes in the presence of a sulfuric acid aerosol catalyst.  

PubMed

Particle growth by the heterogeneous reaction of aldehydes was evaluated in 0.5 m3 Teflon film bags under darkness in the presence of background seed aerosols. The aldehydes used were as follows: glyoxal, butanal, hexanal, octanal, and decanal. To study acid catalyst effects on aldehyde heterogeneous reactions, one of the Teflon bags was initially filled with seed aerosols composed of ammonium sulfate-aerosol acidified with sulfuric acid. These results were compared to particle growth reactions that contained only ammonium sulfate as a background seed aerosol. The gas-phase aldehydes were then added to the Teflon bags. In selected experiments, 1-decanol was also added to the Teflon bags with aldehydes to clarify particle growth via a heterogeneous hemiacetal/acetal formation in the presence/absence of an acid catalyst. The particle size distribution and growth were measured using a scanning mobility particle sizer (TSI-SMPS), and the results were applied to predicting aerosol growth and size distribution changes by condensation and heterogeneous reactions. Aerosols created from the heterogeneous reactions of aldehydes were collected directly on an ungreased zinc selenide (ZnSe) FTIR disk (25 mm in diameter) by impaction. The ZnSe disks were directly analyzed for product functional groups inthe aerosol phase using a Fourier transform infrared (FTIR) spectrometer with a deuterated triglycine sulfate (DTGS) detector. Aerosol growth by heterogeneous aldehyde reactions proceeds via a hydration, polymerization process, and hemiacetal/acetal formation from the reaction of aldehydes with alcohols. These aldehyde heterogeneous reactions were accelerated in the presence of an acid catalyst, H2SO4, and led to higher aerosol yields than when H2SO4 was not present in the seed aerosol. The FTIR spectra obtained from the growing aerosol, also illustrated aldehyde group transformation in the particle phase as a function of the heterogeneous reaction. It was concluded that aldehydes, which can be produced by atmospheric photochemical reactions, can significantly contribute on secondary aerosol formation through heterogeneous reactions in the presence of an acid catalyst. PMID:11775150

Jang, M; Kamens, R M

2001-12-15

161

Heterogeneous diagenetic patterns in the Pleistocene Ironshore Formation of Grand Cayman, British West Indies  

NASA Astrophysics Data System (ADS)

The Ironshore Formation on Grand Cayman consists of six unconformity-bounded units (A to F) that developed in response to repeated transgressive–regressive cycles during the Middle to Late Pleistocene. Corals and matrices in limestones from the Rogers Wreck Point (RWP), offshore George Town (GT), and western onshore (WO) areas are characterized by complex diagenetic fabrics that reflect marine (bioerosion, micrite envelopes, internal sediments, fibrous high-Mg calcite, acicular aragonite, isopachous prismatic calcite cements), freshwater phreatic (circumgranular cements, even/random blocky calcite cements), and vadose (meniscus calcite cements, blocky calcite cements) diagenesis. Throughout these limestones, the matrices have undergone more meteoric diagenetic alteration than the corals. Overall, however, no systematic stratigraphic patterns exist to the distribution of these diagenetic fabrics and it is generally impossible to link the different phases of diagenesis with specific unconformities that cap each unit. These heterogenous patterns of diagenetic features can be attributed to many intrinsic and extrinsic factors, including the original compositions of the different components in the limestones, the porosity and permeability of the substrate, the nature of the diagenetic fluids, climate, and the duration of exposure during each lowstand. Integration of available data, however, indicates that maximum diagenesis took place during the lowstands denoted by the unconformities at the top of Unit C (Marine Isotope Stage 7) and Unit D (Marine Isotope Stage 5e) when long periods of exposure were accompanied by wet climates with high annual rainfalls.

Li, Rong; Jones, Brian

2013-08-01

162

Transport of sorbing solutes in randomly heterogeneous formations: Spatial moments, macrodispersion, and parameter uncertainty  

SciTech Connect

Expressions for the spatial moments and macrodispersion tensor for sorbing solutes in heterogeneous formations were presented using a probabilistic model of a fluid residence time coupled with the particle position analysis. The fluid residence time was defined as a fraction of the actual time during which the particle stayed in the mobile fluid phase of the aquifer. The fluid residence time is a random variable whose variability comes as a result of the non-equilibrium sorption properties. The sorbing solute was assumed to be governed with first-order linear kinetics. The closed-form expressions were based on the stationarity in the kinetic process and on the first-order approximation in the hydraulic conductivity field and in the fluid residence time. The non-equilibrium effects were presented as a function of the spatial variability in hydraulic conductivity and temporal variability in the fluid residence time. The importance of the non-equilibrium processes in the field scale was found to be dependent on reaction rates, retardation factor, mean velocity, and on variance and correlation scale of the hydraulic conductivity. The time needed to reach the asymptotic macrodispersivity is dependent on the degree of non-equilibrium processes and distribution coefficient. The impact from the uncertainty in parameters upon the spatial moments was examined and compared with the organic tracer used in the Borden field experiment.

Andricevic, R.

1993-06-01

163

Application of GPR for 3-D visualization of geological and structural variation in a limestone formation  

Microsoft Academic Search

Ground-penetrating radar (GPR) offers a simple and rapid means of providing valuable information for mapping of geological and structural variations in limestone. Data from closely spaced radar sections were gathered in two areas in Faxe Kalk's limestone quarry on the island of Zealand, Denmark. A `pulseEKKO 100' GPR system with 100 MHz antennas was used for data gathering. In this

Thrainn Sigurdsson; Torben Overgaard

1998-01-01

164

Role of the Structure of Heterogeneous Condensed Mixtures in the Formation of Agglomerates  

Microsoft Academic Search

Mathematical simulation of the structure of metallized heterogeneous condensed mixtures is performed. Evolution of a system of aluminum particles is studied in the case a heat wave passes over the mixture. It is shown that rapid heating of a heterogeneous condensed mixture forms a system of “clusters” of contacting aluminum particles, which may sinter to form a porous system that

S. A. Rashkovskii

2002-01-01

165

Linear equilibrium adsorbing solute transport in physically and chemically heterogeneous porous formations: 1. Analytical solutions  

Microsoft Academic Search

A first-order analytical solution for the transport of reactive solutes in physically and chemically heterogeneous porous media is derived and discussed. The solution relies on the assumption of chemical activity described by the local linear equilibrium assumption postulating the existence of a (spatially variable) retardation factor. Retardation factors and log permeabilities modeling heterogeneities are described statistically by random space functions

Alberto Bellin; Andrea Rinaldo; Willem Jan P. Bosma; Sjoerd E. A. T. M. van der Zee; Yoram Rubin

1993-01-01

166

A Study of the Relationship of Geological Formation to the NORM  

SciTech Connect

Naturally Occurring Radioactive Materials (NORM) is a common and costly contaminant of produced waters associated with natural gas production and exploration. One way of combating this problem is by identifying the problem beforehand. Our approach to this problem involves development of NORM prediction capabilities based on the geological environment. During quarter thirteen of this project, work has continued under the recently approved revisions. We are also in the final stages of sample acquisition from new sampling sites.

Bursh, Talmage P.; Chriss, Derald

1999-10-28

167

Effect of pattern formation on C and N turnover heterogeneity in initial soils  

NASA Astrophysics Data System (ADS)

The formation of vegetation patterns and hydrological processes, among others, result in soil heterogeneity in newly exposed land surfaces. We studied the effect of these developling structures on carbon and nitrogen trunover in soils of the artificial catchment Chicken Creek (Schaaf et al. 2011, 2012). Substrates with different physical and geochemical properties in combination with different labelled plant litter materials were studied in a microcosm experiment over a period of 80 weeks. Main objectives of the microcosm experiment were to determine the transformation processes of C and N from litter decomposition within the gaseous, liquid and solid phase, the interaction with mineral surfaces and its role for the establishment of biogeochemical cycles. The microcosm experiments were established in a climate chamber at constant 10 °C. In total, 48 soil columns (diameter: 14.4 cm; height: 30 cm) were filled with two different quaternary substrates (sand and loamy sand) representing the textural variation within the catchment at a bulk density of 1.4-1.5 g cm-3. The columns were automatically irrigated with artificial rainwater four times a day with 6.6 ml each (corresponding to 600 mm yr-1). The gaseous phase in the headspace of the microcosms was analyzed continuously for CO2 and N2O concentrations. C and N transformation processes were studied using 13C and 15N labelled litter of two different plant species occurring at the catchment (Lotus corniculatus, Calamagrostis epigejos) that was incorporated into the microcosm surface. By including litter from species with wide distribution within the catchment and soil substrates representing the main variation types of the sediments used for catchment construction we were able to characterize the general function of these sub-patches within the catchment with respect to litter decomposition, soil solution composition, DOC and nutrient leaching, and impact on the mineral soil phase. The results suggest that initial differences in substrate composition in combination with invading vegetation leads to the development of patterns with different biogeochemical process intensities within the catchment. These patterns are not mere additive effects of substrates plus litter, but reflect differences in element cycling. Schaaf, W., Bens, O., Fischer, A., Gerke, H.H., Gerwin, W., Grünewald, U., Holländer, H.M., Kögel-Knabner, I., Mutz, M., Schloter, M., Schulin, R., Veste, M., Winter, S. & Hüttl, R.F. (2011): Patterns and processes of initial terrestrial ecosystem development. J Plant Nutr Soil Sci, 174, 229-239. Schaaf, W., Elmer, M., Fischer, A., Gerwin, W., Nenov, R., Pretzsch, H., Seifert, S., Winter, S., Zaplata, M. (2012): Monitoring the formation of structures and patterns during initial development of an artificial catchment. Environmental Monitoring and Assessment. doi: 10.1007/s10661-012-2998-x.

Schaaf, Wolfgang; Zimmermann, Claudia

2013-04-01

168

Inefficient formation of ice via heterogeneous nucleation at temperatures below 200 K  

NASA Astrophysics Data System (ADS)

Nucleation of ice on aerosol particles is an important route to the formation of cirrus and other high altitude clouds in the atmosphere. Here we investigate heterogeneous ice nucleation via deposition mode freezing on both hydrophobic and hydrophilic surfaces using environmental molecular beam experiments and molecular dynamics simulations. We observe that nucleation of ice on a bare graphite crystal becomes increasingly inefficient as the surface temperature decreases from 200 to 155 K. The graphite has a hydrophobic character and water does not wet the surface efficiently in this temperature range. Adsorption of a monolayer of methanol on the graphite surface changes it from hydrophobic to highly hydrophilic. The methanol molecules provide sites for efficient hydrogen-bonding of water molecules, which stabilizes water on the surface compared to the bare graphite. Ice nucleation on the hydrophilic surface takes place at a lower supersaturation than on the hydrophobic surface, and the adsorbate thus influences the absolute nucleation rate at a given temperature. However, the supersaturation required for nucleation increases rapidly with decreasing temperature in the range 175-190 K, and the overall trend with temperature is similar for the bare and methanol-covered surface. Adsorption of a butanol monolayer results in an ice nucleation efficiency intermediate between the other systems. Butanol forms a highly stable solid layer on graphite. Water does not appear to wet the butanol layer efficiently and the water stability on the surface is lower than on the methanol layer. Again, the trend with temperature is similar to the other investigated systems. Thus, while the hydrophilicity of the different surfaces influences the absolute nucleation rate, the overall trend with temperature remains similar. The combination of the present investigations of carbon-based hydrophobic and hydrophilic systems with existing literature provides us with a sufficient data set to allow us to generalize the behavior of the deposition freezing process at low temperatures. Although the substrate plays a role, the overall trends with temperature are similar for different surfaces and therefore the explanation for the observed inefficient nucleation must be related to the inherent properties of water at low temperature. The importance of the results for cloud formation processes in the atmospheres on Earth and Mars are discussed.

Pettersson, J. B. C.; Kong, X.; Thomson, E. S.; Markovic´, N.

2012-04-01

169

Saharan dust and heterogeneous ice formation: Eleven years of cloud observations at a central European EARLINET site  

Microsoft Academic Search

More than 2300 observed cloud layers were analyzed to investigate the impact of aged Saharan dust on heterogeneous ice formation. The observations were performed with a polarization\\/Raman lidar at the European Aerosol Research Lidar Network site of Leipzig, Germany (51.3°N, 12.4°E) from February 1997 to June 2008. The statistical analysis is based on lidar-derived information on cloud phase (liquid water,

P. Seifert; A. Ansmann; I. Mattis; U. Wandinger; M. Tesche; R. Engelmann; D. Müller; C. Pérez; K. Haustein

2010-01-01

170

Geologic Controls on the Growth of Petroleum Reserves  

USGS Publications Warehouse

The geologic characteristics of selected siliciclastic (largely sandstone) and carbonate (limestone and dolomite) reservoirs in North America (largely the continental United States) were investigated to improve our understanding of the role of geology in the growth of petroleum reserves. Reservoirs studied were deposited in (1) eolian environments (Jurassic Norphlet Formation of the Gulf Coast and Pennsylvanian-Permian Minnelusa Formation of the Powder River Basin), (2) interconnected fluvial, deltaic, and shallow marine environments (Oligocene Frio Formation of the Gulf Coast and the Pennsylvanian Morrow Formation of the Anadarko and Denver Basins), (3) deeper marine environments (Mississippian Barnett Shale of the Fort Worth Basin and Devonian-Mississippian Bakken Formation of the Williston Basin), (4) marine carbonate environments (Ordovician Ellenburger Group of the Permian Basin and Jurassic Smackover Formation of the Gulf of Mexico Basin), (5) a submarine fan environment (Permian Spraberry Formation of the Midland Basin), and (6) a fluvial environment (Paleocene-Eocene Wasatch Formation of the Uinta-Piceance Basin). The connection between an oil reservoir's production history and geology was also evaluated by studying production histories of wells in disparate reservoir categories and wells in a single formation containing two reservoir categories. This effort was undertaken to determine, in general, if different reservoir production heterogeneities could be quantified on the basis of gross geologic differences. It appears that reserve growth in existing fields is most predictable for those in which reservoir heterogeneity is low and thus production differs little between wells, probably owing to relatively homogeneous fluid flow. In fields in which reservoirs are highly heterogeneous, prediction of future growth from infill drilling is notably more difficult. In any case, success at linking heterogeneity to reserve growth depends on factors in addition to geology, such as engineering and technological advances and political or cultural or economic influences.

Fishman, Neil S.; Turner, Christine E.; Peterson, Fred; Dyman, Thaddeus S.; Cook, Troy

2008-01-01

171

Etudes de sensibilite relatives aux equivalents de dose associes a un stockage de dechets nucleaires en formation geologique profonde. (Sensitivity analysis concerning dose equivalents associated with the disposal of radioactive wastes in deep geological formations).  

National Technical Information Service (NTIS)

Even if dose calculations may be performed for nuclear waste repositories in deep geological formations, it is unavoidable that the credibility of the obtained results might be affected by huge incertitudes in connection in particular with a lack of preci...

J. Lewi M. J. Mejon-Goula A. Cernes C. Brun-Yaba

1989-01-01

172

Methodology for assessing the risk from the disposal of high-level radioactive wastes in deep geologic formations  

NASA Astrophysics Data System (ADS)

A risk assessment methodology for use in assessing the post closure, long term risk from the disposal of high level radioactive wastes in deep geologic formations. This methodology consists of: (1) techniques for selecting and screening scenarios; (2) models for use in simulating the physical processes and estimating the consequences associated with the occurrence of these scenarios; (3) probabilistic and statistical techniques for use in risk estimates and sensitivity and uncertainty analyses; (4) a procedure for utilizing these models and techniques to arrive at estimates of consequences and risk. The methodology was demonstrated by applying it to the analysis of a hypothetical site containing a bedded salt formation as the host medium for the waste repository. In this demonstration analysis, consequences resulting from the occurrence of several hypothetical scenarios were determined. These consequences were expressed in terms of radionuclide discharges to the biosphere and health effects resulting from these discharges.

Cranwell, R. M.; Ortiz, N. R.; Runkle, G. E.

173

Chemical Composition and Geologic History of Saline Waters in Aux Vases and Cypress Formations, Illinois Basin  

Microsoft Academic Search

Seventy-six samples of formation waters were collected from oil wells producing from the Aux Vases or Cypress Formations in the Illinois Basin. Forty core samples of the reservoir rocks were also collected from the two formations. Analyses of the samples indicated that the total dissolved solids content (TDS) of the waters ranged from 43,300 to 151,400 mg\\/L, far exceeding the

Ilham Demir; Beverly Seyler

1999-01-01

174

Coupling geothermal energy capture with carbon dioxide sequestration in naturally permeable, porous geologic formations -- a novel approach for expanding geothermal energy utilization  

NASA Astrophysics Data System (ADS)

This thesis research presents a new method to harness geothermal energy by combining it with geologic carbon dioxide (CO2) sequestration. CO2 is injected into deep, naturally porous and permeable geologic formations. The geothermally heated CO2 is piped to the surface, used to produce electricity, and then returned to the subsurface. This new approach represents a radical shift in electric/heat power generation as it not only utilizes a renewable energy source but has a negative carbon footprint. This research explores the potential and applicability of the approach and related aspects of geologic fluid and heat flow.

Randolph, Jimmy Bryan

175

Heterogeneous Catalysis.  

ERIC Educational Resources Information Center

|Described is a heterogeneous catalysis course which has elements of materials processing embedded in the classical format of catalytic mechanisms and surface chemistry. A course outline and list of examples of recent review papers written by students are provided. (MVL)|

Miranda, R.

1989-01-01

176

Heterogeneous Catalysis.  

ERIC Educational Resources Information Center

Described is a heterogeneous catalysis course which has elements of materials processing embedded in the classical format of catalytic mechanisms and surface chemistry. A course outline and list of examples of recent review papers written by students are provided. (MVL)

Miranda, R.

1989-01-01

177

Geological and geochemical model of formation of oil and gas accumulations in the South Caspian basin  

SciTech Connect

The South Caspian Sea, Azerbaijan, has been a major petroleum producer since 1848 and is still one of the premier prospective areas for oil and gas in the Soviet Union. Many years of research studies suggest oil and gas in the Soviet Union. Many years of research studies suggest an area of increased prospectivity in the deeper part of the Caspian Sea. Geologic history recorded that a trough developed during the Mesozoic through the Tertiary. The sedimentary sequence is up to 23 km thick. The Pliocene sequence is the major proven productive and prospective interval. Multiple stages of active sedimentation and tectonism took place starting in the early Pliocene and ending in the late Pliocene. Traps were formed and destroyed during the early to late Pliocene. The final tectonic events during the late Pliocene trapped the remigrated oil. Gas and gas condensate probably are within the lower reaches of the basin. Because of the rapid deposition, mud volcanoes were also active. Many are still active today and can be noted in proximity to hydrocarbon deposits. Rapid subsidence and deposition, and anomalously low geothermal regime, and a low maturity of sampled organic matter from the Pliocene section leads to the hypothesis of hydrocarbon generation at depth from older sedimentary rocks. With this proposed geological and geochemical model, the prospectivity for oil and gas deposits is greatly enhanced in aerial extent and possibly to a depth of 9 km.

Narimanov, A.A.

1991-08-01

178

Combined isotope and enantiomer analysis to assess the fate of phenoxy acids in a heterogeneous geologic setting at an old landfill.  

PubMed

Phenoxy acid herbicides and their potential metabolites represent industrial or agricultural waste that impacts groundwater and surface waters through leaching from old landfills throughout the world. Fate assessment of dichlorprop and its putative metabolite 4-CPP (2-(4-chlorophenoxy)propionic acid) is frequently obstructed by inconclusive evidence from redox conditions, heterogeneous geologic settings (e.g. clay till) and ambiguous parent-daughter relationships (i.e. 4-CPP may be daughter product or impurity of dichlorprop). For the first time, a combination of four methods was tested to assess transformation of phenoxy acids at a contaminated landfill (Risby site): analysis of (i) parent and daughter compound concentrations, (ii) enantiomer ratios (iii) compound-specific isotope analysis and (iv) enantiomer-specific isotope analysis. Additionally, water isotopes and chloride were used as conservative tracers to delineate two distinct groundwater flow paths in the clay till. Metabolite concentrations and isotope ratios of chlorinated ethenes demonstrated dechlorination activity in the area with highest leachate concentrations (hotspot) indicating favorable conditions also for dechlorination of dichlorprop to 4-CPP and further to phenoxypropionic acid. Combined evidence from concentrations, enantiomer ratios and isotope ratios of dichlorprop and 4-CPP confirmed their dechlorination in the hotspot and gave evidence for further degradation of 4-CPP downgradient of the hotspot. A combination of 4-CPP enantiomer and isotope analysis indicated different enantioselectivity and isotope fractionation, i.e. different modes of 4-CPP degradation, at different locations. This combined information was beyond the reach of any of the methods applied alone demonstrating the power of the new combined approach. PMID:23168311

Milosevic, N; Qiu, S; Elsner, M; Einsiedl, F; Maier, M P; Bensch, H K V; Albrechtsen, H-J; Bjerg, P L

2012-10-30

179

Stratigraphy, depositional history, and petroleum geology of Lower Cretaceous Fall River formation, Powder River Basin, Wyoming  

Microsoft Academic Search

The middle Albian Fall River Formation, better know to petroleum geologists as the Dakota Sandstone, constitutes a northwestward-thinning wedge of predominantly sandy strata under and overlain by marine shale. Two major episodes of deltaic progradation can be recognized in the formation, permitting mapping of lower and upper deltaic members. Study of outcrops, cores, and subsurface relationships indicates that the Fall

T. A. Ryer; E. R. Gustason

1985-01-01

180

GEODYN2: A Bottom Hole Assembly. Geological Formation Dynamic Interaction Computer Program.  

National Technical Information Service (NTIS)

This paper describes the current development of a three-dimensional transient dynamic finite element computer program, GEODYN2, capable of simulating the behavior of a rotating bottom hole assembly (BHA) interacting with a non-uniform formation. The GEODY...

J. A. Baird B. C. Caskey D. N. Wormley C. M. Stone

1985-01-01

181

Delineation and Correlation of Salinity to Landforms and Geologic Formations, Upper Colorado River Basin.  

National Technical Information Service (NTIS)

The investigation was aimed at assessment of the potential contribution of dissolved mineral salts by natural lands in the Grand and Gunnison River Valleys in the Upper Colorado River Basin. The Mancos, Sego and Mount Garfield formations, are important co...

A. E. Deyo C. G. Higgins K. K. Tanji L. D. Whittig

1986-01-01

182

Geothermal resources: Frio Formation, Middle Texas Gulf Coast. Geological circular 75-8  

Microsoft Academic Search

Regional sand distribution of the Frio Formation is determined; depositional environments are identified; and the geopressured zone and its relationship to sand\\/shale distribution, growth faults, and fluid temperatures in the Middle Texas Gulf Coast are delineated. (MHR)

D. G. Bebout; O. K. Agagu; M. H. Dorfman

1975-01-01

183

Linear equilibrium adsorbing solute transport in physically and chemically heterogeneous porous formations: 2. Numerical results  

Microsoft Academic Search

Numerical Monte Carlo simulations were conducted to assess dispersion of reactive solutes in two-dimensional physically and chemically heterogeneous porous media, using random fields with assigned correlation structure for hydraulic conductivity and linear adsorption coefficient. Conditions under which linearization of adsorption is valid are discussed. Lognormal distributions of hydraulic conductivity and adsorption coefficient were assumed. Calculations have been performed for positive

Willem Jan P. Bosma; Alberto Bellin; Zee van der S. E. A. T. M; Andrea Rinaldo

1993-01-01

184

Federating Distributed and Heterogeneous In formation Sources in Neuroimaging: The NeuroBase Project  

Microsoft Academic Search

The NeuroBase project has for objective the study of the conditions for federating, through Internet, information sources in neuroimaging, where sources are distributed in differ- ent experimental sites, hospitals or research centers in cognitive neurosciences, and contain heterogeneous data and image processing programs. More precisely, this project consists in the creation of a shared ontology, suitable for supporting various neuroimaging

C. Barillot; H. Benali; M. Dojat; A. Gaignard; B. Gibaud; S. Kinkingnéhun; J. P. Matsumoto; M. Pélégrini-Issac; E. Simon; L. Temal

185

Geological formation - drill string dynamic interaction finite-element program (GEODYN). Phase 1. Theoretical description  

SciTech Connect

The Theoretical Description for the GEODYN interactive finite-element computer program is presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit-Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates nonlinear, time-dependent, loading and boundary conditions.

Baird, J.A.; Apostal, M.C.; Rotelli, R.L. Jr.; Tinianow, M.A.; Wormley, D.N.

1984-06-01

186

Phase 1 user instruction manual. A geological formation - drill string dynamic interaction finite element program (GEODYN)  

SciTech Connect

User instructions for the GEODYN Interactive Finite Element Computer Program are presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit - Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates non-linear, time dependent, loading and boundary conditions.

Tinianow, M.A.; Rotelli, R.L. Jr.; Baird, J.A.

1984-06-01

187

The Vicksburg Formation of Texas: Depositional systems distribution, sequence stratigraphy, and petroleum geology  

Microsoft Academic Search

The lower Oligocene Vicksburg Formation of the Gulf Coastal plain contains major petroleum reservoirs in the Rio Grande embayment and is an economically viable target in other areas of Texas. Knowledge of the distribution of Vicksburg depositional systems is essential to understanding sandstone concentrations and, therefore, is fundamental to effective exploration and production of the Vicksburg section. The depositional setting

Combes

1993-01-01

188

Evaluation of the geological relationships to gas hydrate formation and stability  

SciTech Connect

The summaries of regional basin analyses document that potentially economic accumulations of gas hydrates can be formed in both active and passive margin settings. The principal requirement for gas hydrate formation in either setting is abundant methane. Passive margin sediments with high sedimentation rates and sufficient sedimentary organic carbon can generate large quantities of biogenic methane for hydrate formation. Similarly, active margin locations near a terrigenous sediment source can also have high methane generation potential due to rapid burial of adequate amounts of sedimentary organic matter. Many active margins with evidence of gas hydrate presence correspond to areas subject to upwelling. Upwelling currents can enhance methane generation by increasing primary productivity and thus sedimentary organic carbon. Structural deformation of the marginal sediments at both active and passive sites can enhance gas hydrate formation by providing pathways for migration of both biogenic and thermogenic gas to the shallow gas hydrate stability zone. Additionally, conventional hydrocarbon traps may initially concentrate sufficient amounts of hydrocarbons for subsequent gas hydrate formation.

Krason, J.; Finley, P.

1988-01-01

189

Geologic uses of formation microscanner (FMS) in Antelope Shale Cymric field, San Joaquin Valley, California  

Microsoft Academic Search

A comparison between formation microscanner (FMS) log and core from the Cymric field was made to determine the effectiveness of the FMS in characterizing the Antelope Shale. Comparisons of the FMS log and core were based on a detailed core description, petrography, scanning electron microscopy (SEM), and mineralogical analysis. Results indicate that the FMS log in the Antelope Shale is

R. E. White

1989-01-01

190

Regional Geology of the Tiskilwa Till Member, Wedron Formation, Northeastern Illinois,  

National Technical Information Service (NTIS)

The Tiskilwa Till Member, the oldest unit of the Wedron Formation in northern Illinois, was deposited during the early part of the Woodfordian Subage. The wedge-shaped unit is 200 to 300 feet (60 to 90 m) thick in end moraines and 50 to 100 feet (15 to 30...

S. S. Wickham W. H. Johnson H. D. Glass

1988-01-01

191

Innate neural stem cell heterogeneity determines the patterning of glioma formation in children.  

PubMed

The concept that gliomas comprise a heterogeneous group of diseases distinguished by their developmental origin raises the intriguing possibility that neural stem cells (NSCs) from different germinal zones have differential capacities to respond to glioma-causing genetic changes. We demonstrate that lateral ventricle subventricular zone NSCs are molecularly and functionally distinct from those of the third ventricle. Consistent with a unique origin for pediatric low-grade glioma, third ventricle, but not lateral ventricle, NSCs hyperproliferate in response to mutations characteristic of childhood glioma. Finally, we demonstrate that pediatric optic gliomas in Nf1 genetically engineered mice arise from the third ventricle. Collectively, these observations establish the importance of innate brain region NSC heterogeneity in the patterning of gliomagenesis in children and adults. PMID:22789544

Lee, Da Yong; Gianino, Scott M; Gutmann, David H

2012-07-10

192

Aspherical structural heterogeneity within the uppermost inner core: Insights into the hemispherical boundaries and core formation  

NASA Astrophysics Data System (ADS)

Lateral heterogeneities at the top of the inner core are investigated using earthquakes that occurred in Indonesia and southeast Asia and were recorded in the southeastern Caribbean. Using seismic observations of attenuation and seismic velocity, we were able to constrain the characteristics of the boundary between the inner and outer core to further investigate the dynamics and evolution of the Earth's core. Our seismic observations from core phases confirm that the outermost inner core is asymmetrically heterogeneous and we are able to further constrain the morphology and physical properties of this layer. Comparison of data from earthquakes with ray paths traversing from east to the west versus those with ray paths from west to east allow us to map the aspherical heterogeneity of the boundary layer and specifically image the boundary between the proposed quasi-eastern and western hemispheres of the inner core. The variation of differential travel times between PKPdf and PKPbc, attenuation in terms of Q factor, and latitudinal changes for both of these observations, can be attributed to localized heterogeneity at the quasi-hemispherical boundaries of the inner core. We constrain the change in the thickness of outermost core boundary layer from 100 to 250 km within a distance of a few 10s of kilometers at 45°E ± 2°, for the western boundary, with an overall P-wave velocity decrease in the western hemisphere of 0.5% and increase of 0.5% in the eastern hemisphere. We constrain the eastern boundary at latitudes greater than 45°N to 173°E ± 4° with an overall P-wave velocity decrease in the western hemisphere of 1.0% in the uppermost 200 km of the inner core. The eastern boundary at equatorial latitudes is constrained to a region <170°E with a western hemisphere with a 0.5% drop in P-wave velocity in the uppermost 250 km.

Miller, Meghan S.; Niu, Fenglin; Vanacore, Elizabeth A.

2013-10-01

193

Network effects, heterogeneous time value and network formation in the airline market  

Microsoft Academic Search

This study examines an airline firm's adoption of a hub–spoke network or a point-to-point network when considering network effects from the demand side and the heterogeneity of passengers' time value.The results of this study reveal the following: If the time value for leisure passengers is sufficiently small and the operating cost is medium or when the time value for leisure

Akio Kawasaki

2008-01-01

194

Formation of the vertical heterogeneity in the Lake Shira ecosystem: the biological mechanisms and mathematical model  

Microsoft Academic Search

Data on the seasonal changes in vertical heterogeneity of the physical-chemical and biological parameters of the thermally stratified Shira Lake ecosystem (Khakasia, Siberia) in 1996–2000 have been analyzed. The interaction mechanisms involving: (1) The plankton populations in aerobic and anaerobic zones, involving the cycling of carbon and sulphur, (2) the primary production limitation (by light and phosphorus) and inhibition (by light), and

Andrei G. Degermendzhy; Victor M. Belolipetsky; Tatiana A. Zotina; Ramesh D. Gulati

2002-01-01

195

A geological formation: Drill string dynamic interaction finite element program (GEODYN2)  

SciTech Connect

The Theoretical Description for the GEODYN2 Interactive Finite Element Computer Program is presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit-BHA finite element model arising from the intermittent contact of the PDC Bit-BHA System with the downhole rock formations. The program accommodates nonlinear, time dependent, loading and boundary conditions. 15 refs., 28 figs., 2 tabs.

Baird, J.A.; Apostal, M.C. (Jordan, Apostal, Ritter Associates, Inc., Davisville, RI (USA)); Wormley, D.N. (Massachusetts Inst. of Tech., Cambridge, MA (USA))

1989-12-01

196

User instruction manual for GEODYN2: A geological formation--bottom hole assembly  

SciTech Connect

User instructions for the GEODYN2 Interactive Finite Element Computer Program are presented along with the required data file utilization and naming conventions. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a bottom hole assembly (BHA) and Polycrystalline Diamond Compact Bit arising from the intermittent contact of the BHA with the downhole rock formations. The program accommodates nonlinear, time dependent, loading and boundary conditions. 19 refs., 38 figs., 14 tabs.

Apostal, M.C.; Baird, J.A. (Jordan, Apostal, Ritter Associates, Inc., Davisville, RI (USA))

1987-06-01

197

The geology and mechanics of formation of the Fort Rock Dome, Yavapai County, Arizona  

USGS Publications Warehouse

The Fort Rock Dome, a craterlike structure in northern Arizona, is the erosional product of a circular domal uplift associated with a Precambrian shear zone exposed within the crater and with Tertiary volcanism. A section of Precambrian to Quaternary rocks is described, and two Tertiary units, the Crater Pasture Formation and the Fort Rock Creek Rhyodacite, are named. A mathematical model of the doming process is developed that is consistent with the history of the Fort Rock Dome.

Fuis, Gary S.

1996-01-01

198

Triply stacked heterogeneous array of porphyrins and phthalocyanine through stepwise formation of a fourfold rotaxane and an ionic complex.  

PubMed

We report the preparation and crystal structure of a triply stacked metal complex array in which a Cu-phthalocyanine is sandwiched between different Cu-porphyrins. The discrete heterogeneous assembly was prepared through formation of a fourfold rotaxane from a tetradactyl porphyrin with alkylammonium moieties and a phthalocyanine bearing four crown ethers and the subsequent formation of an ionic complex between the fourfold rotaxane and a tetraanionic porphyrin. The tetraanionic porphyrin, Cu-TPPS(4-), is selectively bound to the fourfold rotaxane through cooperative ?-? and ionic interactions. The crystal structure revealed the columnar stacked array of the three planar building components in a precise order and spatial arrangement that promote intermolecular electronic communication. PMID:23889684

Yamada, Yasuyuki; Mihara, Nozomi; Shibano, Shinya; Sugimoto, Kunihisa; Tanaka, Kentaro

2013-07-26

199

Multi-Scale Modeling of CO2 and Brine Flow in Geologic Formations Containing Faults  

NASA Astrophysics Data System (ADS)

Basins being considered for geologic storage of CO2 contain faults that can act as conduits for flow. The flow of CO2 and brine in and around faults involves relatively small-scale processes, when compared to typical grid-cell sizes in basin-scale numerical models. A computationally efficient approach to multi-phase flow modeling of basins containing faults can be developed based on embedding analytical solutions to represent small-scale features (like faults) within larger-scale numerical models. This approach is analogous to the use of analytical solutions for flow around wells as sub-scale corrections in numerical models (e.g. Peaceman (1978), Gasda et al. (2009)). However, the modeling approach for faults departs from wells due to the possibility of the fault extending beyond one numerical grid block, and its underlying Cartesian, rather than cylindrical, geometry. The combined analytical-numerical multi-scale (CAN-MS) model for faults is composed of (1) numerical approximation for the basin-scale flow system, (2) analytical solutions for the small-scale flow regimes for a given fault, and (3) the coupling between basin and small-scale flow systems. Following the approach of Nordbotten and Celia (2006) given in radial coordinates, analytical solutions representing different flow conditions in and around faults are derived in Cartesian coordinates for a stationary problem with a finite outer boundary. The solutions are based on mass conservation equations, Darcy's Law, and structured vertical flow to represent vertical non-equilibrium. These solutions are used to determine the fluxes along the fault and to derive pressure corrections that relate pressure at a given fault to the (average) pressure in the numerical grid blocks. The flow and pressure solutions are solved simultaneously to describe the small-scale effects of the fault and produce an output in a form that is compatible with the coarse-scale numerical model. Model test results will be presented to facilitate future application of the CAN-MS model to real basins such as the Illinois Basin.

Kang, M.; Nordbotten, J. M.; Celia, M. A.

2011-12-01

200

Heterogeneous formation of polar stratospheric clouds-nucleation of nitric acid trihydrate (NAT) in the arctic stratosphere  

NASA Astrophysics Data System (ADS)

Satellite based observations during the Arctic winter of 2009/2010 provide firm evidence that, in contrast to the current theory, the nucleation of nitric acid trihydrate (NAT) in the polar stratosphere does not only occur on preexisting ice particles. In order to explain the NAT clouds observed over the Arctic in mid December 2009, a heterogeneous nucleation mechanism is required, occurring on the surface of dust or meteoritic particles. For the first time, a detailed microphysical modelling of this NAT formation pathway has been carried out. Heterogeneous NAT formation was calculated along tens of thousands of trajectories, ending at Cloud Aerosol Lidar with Orthogonal Polarisation (CALIOP) observation points. Comparing the optical properties of the modelled NAT PSCs with these observations enables the thorough validation of a newly developed NAT nucleation parameterisation, which has been built into the Zurich Optical and Microphysical box Model (ZOMM). The parameterisation is based on active site theory and is simple to implement in models. It is shown that the new method is capable of reproducing observed PSCs very well, despite the varied conditions experienced by air parcels travelling along the different trajectories.

Hoyle, C. R.; Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Grooß, J.-U.; Peter, T.

2013-05-01

201

Survey of naturally occurring hazardous materials in deep geologic formations: a perspective on the relative hazard of deep burial of nuclear wastes  

Microsoft Academic Search

Hazards associated with deep burial of solidified nuclear waste are considered with reference to toxic elements in naturally occurring ore deposits. This problem is put into perspective by relating the hazard of a radioactive waste repository to that of naturally occurring geologic formations. The basis for comparison derives from a consideration of safe drinking water levels. Calculations for relative toxicity

K. A. Tonnessen; J. J. Cohen

1977-01-01

202

A review of the ANDRA's research programmes on the thermo-hydromechanical behavior of clay in connection with the radioactive waste disposal project in deep geological formations  

Microsoft Academic Search

This paper presents the different studies realized or launched by ANDRA in collaboration with different contractors, including laboratory and in situ experiments, as well as physical and numerical modelizations, related to the thermo-hydromechanical behavior of clays and clayey materials. Clays are considered as both potential host rocks and sealing materials, among other geological formations and materials, respectively.The study of a

B. Félix; P. Lebon; R. Miguez; F. Plas

1996-01-01

203

Geological features indicative of processes related to the hematite formation in Meridiani Planum and Aram Chaos, Mars: a comparison with diagenetic hematite deposits in southern Utah, USA  

Microsoft Academic Search

In order to understand the formation of the few but large, hematite deposits on Mars, comparisons are often made with terrestrial hematite occurrences. In southern Utah, hematite concretions have formed within continental sandstones and are exposed as extensive weathered-out beds. The hematite deposits are linked to geological and geomorphological features such as knobs, buttes, bleached beds, fractures and rings. These

Jens Ormö; Goro Komatsu; Marjorie A. Chan; Brenda Beitler; William T. Parry

2004-01-01

204

Influence of Culture Heterogeneity in Cell Surface Charge on Adhesion and Biofilm Formation by Enterococcus faecalis  

Microsoft Academic Search

Biofilm formation is an increasing problem in medicine, due to the intrinsic resistance of microorganisms in the biofilm mode of growth against the host immune system and antimicrobial therapy. Adhesion is an important step in biofilm formation, influenced, among other factors, by the surface hydrophobicities and charges of both the substratum and the adhering microorganisms. Enterococcus faecalis strains generally display

Annet E. J. van Merode; Henny C. van der Mei; Henk J. Busscher; Bastiaan P. Krom

2006-01-01

205

GEODYN2: a bottom hole assembly. Geological formation dynamic interaction computer program  

SciTech Connect

This paper describes the current development of a three-dimensional transient dynamic finite element computer program, GEODYN2, capable of simulating the behavior of a rotating bottom hole assembly (BHA) interacting with a non-uniform formation. The GEODYN2 Program facilitates a very detailed analysis/simulation of the behavior of a BHA with a polycrystalline diamond compact (PDC) bit and various stabilizer designs. The basic drill string mechanics implemented within the program, the overall algorithm, and the more pertinent modeling features which permit this level of analysis are briefly outlined. The implementation of these features and how they allow calculation of the response behavior of a bottom hole assembly are demonstrated. Although the development and enhancement of modeling capabilities within GEODYN2 is ongoing, it is anticipated that the preliminary verification results thus far generated will further the understanding of the response behavior of BHAs. 9 refs., 16 figs.

Baird, J.A.; Caskey, B.C.; Wormley, D.N.; Stone, C.M.

1985-01-01

206

The Impact of Geologic Heterogeneity on Stream Temperatures in the McKenzie River, Oregon: Implications for Climate Change and Land Use  

Microsoft Academic Search

Stream temperature is recognized as an important component of water quality for aquatic life; less well understood is how the regional geologic setting controls stream temperature regimes. The McKenzie River watershed in western Oregon exhibits significant differences in geology and rock age between two contiguous volcanic provinces: the Plio-Pleistocene High Cascades and the Tertiary Western Cascades. Streamflow regimes from spring-fed

M. J. Farrell; C. Tague; G. E. Grant; A. Jefferson; S. L. Lewis

2004-01-01

207

Geological hydrogen storage  

Microsoft Academic Search

The probably least expensive form of hydrogen storage would be geological storage in formations easy to excavate, such as salt dome intrusions near the surface (which can be excavated by water flushing) or vertically curved, capped aquifer layers not requiring excavation at all. Such geological formation are already in use for natural gas storage and have proven very stable. Consideration

Bent Sørensen

208

Evaluation of the geological relationships to gas hydrate formation and stability  

SciTech Connect

During the reported year we have enhanced our knowledge on and gained considerable experience in assessment of the gas hydrate resources in the offshore environments. Specifically, we have learned and gained experience in the following: Efficiently locating data sources, including published literature and unpublished information. We have established personal communication extremely critical in data accessability and acquisition. We have updated information pertinent to gas hydrate knowledge, also based on thorough study and evaluation of most Russian literature and additional publications in languages other than English. Besides critical evaluation of widely spread literature, in many cases our reports include previously unpublished information (e.g. BSRs from the Gulf of Mexico). The assessment of the gas resources potential associated with the gas hydrates, although in most cases at a low level of confidence, appears also very encouraging for further, more detailed, study. We are also confident that, because of the present reports' format, new data and a concept-oriented approach, the result of our study will be of strong interest to various industries, research institutions and numerous governmental agencies.

Not Available

1985-01-01

209

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

210

Advanced modulation formats for delivery of heterogeneous wired and wireless access networks  

NASA Astrophysics Data System (ADS)

It is believed that the integration of wired and wireless access networks (or heterogeneous network) will provide high bandwidth and flexibility for both fixed and mobile users in a single and cost-effective platform. Here, we propose and demonstrate a signal remodulated wired and wireless network with wireless signal broadcast. Dark-return-to-zero (DRZ) and polarization-shift-keying (PolSK) signals are used for the downstream wired and wireless applications respectively. At the remote antenna unit (RAU), the PolSK signal is demodulated to produce the binary-phase-shift-keying (BPSK) signal, which will be used for the wireless broadcast application. Signal remodulation is demonstrated using reflective semiconductor optical amplifier (RSOA) as a colorless reflective modulator in the optical networking unit (ONU)/RAU. The downstream signal is remodulated at the ONU/RAU to produce the non-return-to-zero (NRZ) upstream signal.

Chow, C. W.; Yeh, C. H.

2009-12-01

211

The formation and functional consequences of heterogeneous mitochondrial distributions in skeletal muscle  

PubMed Central

SUMMARY Diffusion plays a prominent role in governing both rates of aerobic metabolic fluxes and mitochondrial organization in muscle fibers. However, there is no mechanism to explain how the non-homogeneous mitochondrial distributions that are prevalent in skeletal muscle arise. We propose that spatially variable degradation with dependence on O2 concentration, and spatially uniform signals for biogenesis, can account for observed distributions of mitochondria in a diversity of skeletal muscle. We used light and transmission electron microscopy and stereology to examine fiber size, capillarity and mitochondrial distribution in fish red and white muscle, fish white muscle that undergoes extreme hypertrophic growth, and four fiber types in mouse muscle. The observed distributions were compared with those generated using a coupled reaction-diffusion/cellular automata (CA) mathematical model of mitochondrial function. Reaction-diffusion analysis of metabolites such as oxygen, ATP, ADP and PCr involved in energy metabolism and mitochondrial function were considered. Coupled to the reaction-diffusion approach was a CA approach governing mitochondrial life cycles in response to the metabolic state of the fiber. The model results were consistent with the experimental observations and showed higher mitochondrial densities near the capillaries because of the sometimes steep gradients in oxygen. The present study found that selective removal of mitochondria in the presence of low prevailing local oxygen concentrations is likely the primary factor dictating the spatial heterogeneity of mitochondria in a diversity of fibers. The model results also suggest decreased diffusional constraints corresponding to the heterogeneous mitochondrial distribution assessed using the effectiveness factor, defined as the ratio of the reaction rate in the system with finite rates of diffusion to that in the absence of any diffusion limitation. Thus, the non-uniform distribution benefits the muscle fiber by increasing the energy status and increasing sustainable metabolic rates.

Pathi, B.; Kinsey, S. T.; Howdeshell, M. E.; Priester, C.; McNeill, R. S.; Locke, B. R.

2012-01-01

212

Geologic and climatic controls on the formation of the Permian coal measures in the Sohagpur coal field, Madhya Pradesh, India  

SciTech Connect

The U.S. Geological Survey (USGS) and the Geological Survey of India (GSI) are concluding a cooperative study of the coking coal deposits in the Sohagpur coal field in central India. Because of the importance of coal in India's economy, the Coal Wing of the Geological Survey of India has studied the area intensely since the early 1980's. This report summarizes the overall stratigraphic, tectonic, and sedimentologic framework of the Sohagpur coal field area, and the interpretations of the geologic and climatic environments required for the accumulation of the thick Gondwana coal deposits, both coking and non-coking.

Milici, R.C.; Warwick, P.D.; Mukhopadhyah, A.; Adhikari, S.; Roy, S.P.; Bhattacharyya, S.

1999-07-01

213

Effect of modeling factors on the dissolution-diffusion-convection process during CO2 geological storage in deep saline formations  

NASA Astrophysics Data System (ADS)

It is well known that during CO2 geological storage, density-driven convective activity can significantly accelerate the dissolution of injected CO2 into water. This action could limit the escape of supercritical CO2 from the storage formation through vertical pathways such as fractures, faults and abandoned wells, consequently increasing permanence and security of storage. First, we investigated the effect of numerical perturbation caused by time and grid resolution and the convergence criteria on the dissolution-diffusion-convection (DDC) process. Then, using the model with appropriate spatial and temporal resolution, some uncertainty parameters investigated in our previous paper such as initial gas saturation and model boundaries, and other factors such as relative liquid permeability and porosity modification were used to examine their effects on the DDC process. Finally, we compared the effect of 2D and 3D models on the simulation of the DDC process. The above modeling results should contribute to clear understanding and accurate simulation of the DDC process, especially the onset of convective activity, and the CO2 dissolution rate during the convection-dominated stage.

Zhang, Wei

2013-06-01

214

Preliminary modeling of the long-term fate of CO2 following injection into deep geological formations  

SciTech Connect

The injection of CO2 into deep saline aquifers is a potential option for greenhouse gas mitigation. However, several key issues, such as underground storage time and the fate of the injected CO2, must be studied before this option becomes economically and socially acceptable. In the current study, a one-dimensional reactive mass-transport model was used to predict the long-term chemical behavior of a deep saline aquifer following CO2 injection, far away from the injection site and representative of basin-scale migration and long-term fate. The dissolution of the injected CO2 into brine causes a sharp drop in pH, and consequently, the acidic brine aggressively reacts with aquifer minerals. Our model also predicts the dissolution of aluminosilicate minerals with the formation of secondary minerals and the precipitation and dissolution of carbonate minerals and is consistent with laboratory-scale CO2 core-flooding experiments. However, the extent and development of reaction fronts depend on the reaction rates used. For example, our modeling results indicate that the transport of carbon can be significantly retarded with respect to the flow of the brine itself, and a significant amount of injected CO2 is immobilized because of mineral trapping. The precise locations and patterns of the carbon reactive transport are sensitive to the reaction rates used, illustrating the need for improved knowledge of reaction kinetics, particularly the in-situ rates of dissolution and precipitation of aluminosilicate minerals, in evaluating mineral trapping of CO2 in deep geological formations.

Strazisar, B.R.; Shu, C.; Hedges, S.W.

2006-03-01

215

Geological evolution and analysis of confirmed or suspected gas hydrate localities: Volume 9, Formation and stability of gas hydrates of the Middle America Trench  

SciTech Connect

This report presents a geological description of the Pacific margin of Mexico and Central America, including regional and local structural settings, geomorphology, geological history, stratigraphy, and physical properties. It provides the necessary regional and geological background for more in-depth research of the area. Detailed discussion of bottom simulating acoustic reflectors, sediment acoustic properties, and distribution of hydrates within the sediments are also included in this report. The formation and stabilization of gas hydrates in sediments are considered in terms of phase relations, nucleation, and crystallization constraints, gas solubility, pore fluid chemistry, inorganic diagenesis, and sediment organic content. Together with a depositional analysis of the area, this report is a better understanding of the thermal evolution of the locality. It should lead to an assessment of the potential for both biogenic and thermogenic hydrocarbon generation. 150 refs., 84 figs., 17 tabs.

Finley, P.; Krason, J.

1986-12-01

216

Geological evolution and analysis of confirmed or suspected gas hydrate localities: Volume 2, basin analysis, formation and stability of gas hydrates in the Black Sea  

SciTech Connect

This document is Volume 11 of a series of reports entitled ''Geological Evolution and Analysis Confirmed or Suspected Gas Hydrate Localities.'' Volume 11 provides an analysis of the Black Sea region. The report presents a geological description of the Black Sea region, including regional and local structural settings, geomorphology, geological history, stratigraphy, and physical properties. Included also is a discussion of bottom simulating acoustic reflectors, sediment acoustic properties, distribution of hydrates within the sediments, and the relation of hydrate distribution to other features such as salt dispirism. The formation and stabilization of gas hydrates in sediments are discussed in terms of phase relations, nucleation, and crystallization constraints, gas solubility, pore fluid chemistry, inorganic diagenesis, and sediment organic content. A depositional analysis of the areas is discussed in order to better understand the thermal evolution of the locality and to assess the potential for thermogenic hydrocarbon generation. 80 refs., 27 figs., 16 tabs.

Ciesnik, M.S.; Krason, J.

1987-05-01

217

Spontaneous Formation of Tumorigenic Hybrids between Breast Cancer and Multipotent Stromal Cells Is a Source of Tumor Heterogeneity  

PubMed Central

Breast cancer progression involves cancer cell heterogeneity, with generation of invasive/metastatic breast cancer cells within populations of nonmetastatic cells of the primary tumor. Sequential genetic mutations, epithelial-to-mesenchymal transition, interaction with local stroma, and formation of hybrids between cancer cells and normal bone marrow–derived cells have been advocated as tumor progression mechanisms. We report herein the spontaneous in vitro formation of heterotypic hybrids between human bone marrow–derived multipotent stromal cells (MSCs) and two different breast carcinoma cell lines, MDA-MB-231 (MDA) and MA11. Hybrids showed predominantly mesenchymal morphological characteristics, mixed gene expression profiles, and increased DNA ploidy. Both MA11 and MDA hybrids were tumorigenic in immunodeficient mice, and some MDA hybrids had an increased metastatic capacity. Both in culture and as xenografts, hybrids underwent DNA ploidy reduction and morphological reversal to breast carcinoma–like morphological characteristics, while maintaining a mixed breast cancer–mesenchymal expression profile. Analysis of coding single-nucleotide polymorphisms by RNA sequencing revealed genetic contributions from both parental partners to hybrid tumors and metastasis. Because MSCs migrate and localize to breast carcinoma, our findings indicate that formation of MSC–breast cancer cell hybrids is a potential mechanism of the generation of invasive/metastatic breast cancer cells. Our findings reconcile the fusion theory of cancer progression with the common observation that breast cancer metastases are generally aneuploid, but not tetraploid, and are histopathologically similar to the primary neoplasm.

Rappa, Germana; Mercapide, Javier; Lorico, Aurelio

2012-01-01

218

Geologic Maps  

NSDL National Science Digital Library

This web site provides an introduction to geologic maps. Topics covered include what is a geologic map, unique features of geologic maps, letter symbols, faults, and strike and dip. Users may click to view colored geologic maps, the geologic map of the United States and the geologic relief map of the United States.

Graymer, Russell

219

Technique of Formation of an Axisymmetric Heterogeneous Flow During Thermal Spraying of Powder Materials  

NASA Astrophysics Data System (ADS)

The paper presents an investigation of a unit of annular injection of powder materials into a thermal plasma flow. The unit is designed for the electric-arc direct-current plasma torch with a sectioned inter-electrode insert up to 100 kW, which was developed earlier. Energy characteristics (thermal efficiency and thermal power of the plasma jet) and spectra of plasma torch current and voltage fluctuations are described. The characteristics of the radial temperature distribution in the plasma jet in the annular and point powder injection cases are compared. A multi-channel spectrometer with a photo-diode array was implemented for the measurements. It is shown that, in contrast to point injection of powder particles, which is carried out across the jet on the nozzle exit, distributed annular injection with gas-dynamic focusing provides a dense axisymmetric heterogeneous flow, in which almost all particles pass through a high-temperature and high-speed area near the plasma jet axis.

Kuz'min, V. I.; Mikhal'Chenko, A. A.; Kovalev, O. B.; Kartaev, E. V.; Rudenskaya, N. A.

2012-01-01

220

An integrative geologic, geochronologic and geochemical study of Gorgona Island, Colombia: Implications for the formation of the Caribbean Large Igneous Province  

NASA Astrophysics Data System (ADS)

The genesis of the Caribbean Large Igneous Province (CLIP) has been associated to the melting of the Galapagos plume head at ~ 90 Ma or to the interaction between the plume and the Caribbean slab window. Gorgona Island, offshore western Colombia, is an accreted fragment of the CLIP and its highly heterogeneous igneous suite, ranging from enriched basalts to depleted komatiites and picrites, was assumed to have formed at ~ 89 Ma from different part of the plume. Here we present new geologic, geochronologic and geochemical data of Gorgona with significant implications for the formation of the CLIP. A new set of 40Ar- 39Ar ages documents a magmatic activity spanning the whole Late Cretaceous (98.7 ± 7.7 to 64.4 ± 5 Ma) followed by a shallower, picritic pyroclastic eruption in the Paleocene. Trace element and isotope geochemistry confirm the existence of an enriched (EDMM: La/Sm N ? 1 and ?Nd i of 5.7 to 7.8) and a depleted (DMM: La/Sm N < 1 and ?Nd i of 9.5 to 11.3) mantle sources. A progressive increase in the degree of melting and melt extraction with time occurred in both groups. Petrologic modeling indicates that low but variable degrees of wet melting (< 5%) of an EDMM can produce the LREE-enriched rocks. Higher degree of melting (> 10%) of a mixed DMM + EDMM (40 to 60%) may reproduce the more depleted rocks with temperatures in the range of ambient mantle in absence of plumes. Our results contradict the notion that the CLIP formed by melting of a plume head at ~ 90 Ma. Multiple magmatic pulses over several tens of Ma in small areas like Gorgona, also recognized in other CLIP areas, suggest a long period of diffuse magmatism without a clear pattern of migration. The age span of this magmatism is broadly concurrent with the Caribbean slab window. During this time span the Farallon oceanic lithosphere (later becoming the Caribbean plate) advanced eastward ~ 1500 km, overriding the astenosphere feeding the proto-Caribbean spreading ridge. This hotter mantle flowed westward into, and mixed with, the opening mantle wedge, promoting increasing melting with time. The fortuitous occurrence of a plume passing through the slab gap area cannot be excluded but not required to produce the observed composition and degree of melting.

Serrano, Lina; Ferrari, Luca; Martínez, Margarita López; Petrone, Chiara Maria; Jaramillo, Carlos

2011-09-01

221

Regional geology of the low-permeability, gas-bearing Cleveland Formation, western Anadarko Basin, Texas Panhandle: Lithologic and depositional facies, structure, and sequence stratigraphy  

NASA Astrophysics Data System (ADS)

The Upper Pennsylvania (lower Missourian) Cleveland formation produces gas from low-permeability ('tight') sandstone reservoirs in the western Anadarko Basin of the northeastern Texas Panhandle. In the six-county region, these reservoirs had produced more than 412 Bcf of natural gas through December 31, 1989. Because of their typically low permeability, the Cleveland sandstones require acidizing and hydraulic fracture treatment to produce gas at economic rates. Since 1982, the Gas Research Institute has supported geological investigations throughout the United States to develop the scientific and technological knowledge for producing from low-permeability, gas-bearing sandstones. As part of the program and the GRI Tight Gas Sands project, the Bureau of Economic Geology has been conducting research on low-permeability sandstones in the Cleveland formation and on several other sandstone units of similar character in Texas and Wyoming.

Hentz, Tucker F.

1992-09-01

222

Evaluation of the geological relationships to gas hydrate formation and stability. Second annual technical progress report, October 1, 1985--September 30, 1986  

SciTech Connect

Although there are many publications pertaining to gas hydrates, their formation and stability in various geological conditions are poorly known. Therefore, for the same reasons and because of the very broad scope of our research, limited amount and extremely dispersed information, the study regions are very large. Moreover, almost without exception the geological environments controlling gas hydrates formation and stability of the studied regions are very complex. The regions studied (completed and partially completed - total 17 locations) during the reporting period, particularly the Gulf of Mexico and the Middle America Trench, are the most important in this entire research project. In the past, both of these regions have been extensively studied, the presence of gas hydrates confirmed and samples recovered. In our investigation it was necessary not only to review all previous data and interpretations, but to do a thorough analysis of the basins, and a critical evaluation of an previously reported and publicly available but not published information.

Not Available

1986-12-31

223

Seasonal variations and depth dependence of soil radon concentration levels in different geological formations in Deir Abu-Said District, Irbid—Jordan  

Microsoft Academic Search

Soil radon concentration levels in Deir Abu-Said District, Irbid—Jordan were measured using CR-39 track detectors in both summer and winter at several depths over six geological formations.Seasonal variations of soil radon were measured at five depths (10, 25, 50, 75 and 100cm). At a depth of 100cm; soil radon concentration levels, in summer, range from 6.85kBqm-3 for Muwaqqar Chalky-Marl (MCM)

S. A. Al-Shereideh; B. A. Bataina; N. M. Ershaidat

2006-01-01

224

Geological Evolution of Lada Terra, Venus  

NASA Astrophysics Data System (ADS)

This paper presents geologic history of Lada Terra of Venus. Geological mapping revealed formation of large-scale extensional belts, coronae, and volcanogenic plains. The sequence of geologic events provides clues to deeper geodynamic processes.

Kumar, P. S.; Head, J. W.

2011-03-01

225

Amazonis Planitia: The role of geologically recent volcanism and sedimentation in the formation of the smoothest plains on Mars  

NASA Astrophysics Data System (ADS)

Amazonis Planitia, located between the two main volcanic provinces on Mars (Tharsis and Elysium), is characterized by extremely smooth topography at several scale lengths, as smooth as oceanic abyssal plains topography on Earth. We use Mars Global Surveyor (MGS) data (primarily very high resolution Mars Orbiter Laser Altimeter (MOLA) topography and derivative slope maps, gradient maps, and detrended maps) to examine the surface morphology of Amazonis Planitia and the stratigraphic relationships among previously mapped and newly defined units. These new data reveal the presence of a 1300 km diameter Noachian impact basin in northwest Amazonis Planitia and an extensive Late Hesperian lava flow unit that appears to have originated from the Olympus Mons source area prior to aureole formation. The presence of this previously unrecognized flow unit strongly suggests that Olympus Mons activity dates back to at least the Hesperian, as did activity on the Tharsis Montes. Emplacement of this ~100 meter thick flow unit formed a barrier along the northern margin of Amazonis Planitia which had a profound influence on the subsequent geologic history of the region. Formation of Olympus Mons aureole deposits created an eastern topographic barrier, and subsequent Tharsis Montes lava flows entered the basin from the south, flowing around the aureole. These three barriers (degraded Noachian crater rim, proto-Olympus Mons flow unit, and Olympus Mons aureole) caused subsequent lava flows and outflow channel effluents, primarily from the Elysium region to the west, to pond on the floor of Amazonis Planitia, preferentially smoothing the terrain there. Mars Orbiter Camera (MOC) images substantiate that at least two very fluid lava flows alternated with fluvial episodes from Elysium Planitia, flowing through Marte Valles onto the floor of the Amazonis Planitia basin. Within Amazonis Planitia, MOC images show flow-like textures heavily mantled by sediments, and radar data reveal the presence of rough lava flow surfaces underlying the sedimentary debris. These data thus suggest that the unique smoothness of Amazonis Planitia is the result of deposition of thin fluid lava flows and fluvial sediments in an enclosed basin. Crater counts suggest that the most recent resurfacing may have occurred in the latest Amazonian Period, in the last 1% of the history of Mars. In light of its unique history, it is somewhat ironic to note that Amazonis Planitia was originally thought to be a typical young Martian surface and therefore used to name the Amazonian era.

Fuller, Elizabeth R.; Head, James W.

2002-10-01

226

Thermal Decomposition of Gaseous Ammonium Nitrate at Low Pressure: Kinetic Modeling of Product Formation and Heterogeneous Decomposition of Nitric Acid  

NASA Astrophysics Data System (ADS)

The thermal decomposition of ammonium nitrate, NH4NO3 (AN), in the gas phase has been studied at 423-56 K by pyrolysis/mass spectrometry under low-pressure conditions using a Saalfeld reactor coated with boric acid. The sublimation of NH4NO3 at 423 K was proposed to produce equal amounts of NH3 and HNO3, followed by the decomposition reaction of HNO3, HNO3 + M ? OH + NO2 + M (where M = third-body and reactor surface). The absolute yields of N2, N2O, H2O, and NH3, which can be unambiguously measured and quantitatively calibrated under a constant pressure at 5-6.2 torr He are kinetically modeled using the detailed [H,N,O]-mechanism established earlier for the simulation of NH3-NO2 (Park, J.; Lin, M. C. Technologies and Combustion for a Clean Environment. Proc. 4th Int. Conf. 1997, 34-1, 1-5) and ADN decomposition reactions (Park, J.; Chakraborty, D.; Lin, M. C. Proc. Combust. Inst. 1998, 27, 2351-2357). Since the homogeneous decomposition reaction of HNO3 itself was found to be too slow to account for the consumption of reactants and the formation of products, we also introduced the heterogeneous decomposition of HNO3 in our kinetic modeling. The heterogeneous decomposition rate of HNO3, HNO3 + (B2O3/SiO2) ? OH + NO2 + (B2O3/SiO2), was determined by varying its rate to match the modeled result to the measured concentrations of NH3 and H2O; the rate could be represented by k2b = 7.91 × 107 exp(-12 600/T) s-1, which appears to be consistent with those reported by Johnston and co-workers (Johnston, H. S.; Foering, L.; Tao, Y.-S.; Messerly, G. H. J. Am. Chem. Soc. 1951, 73, 2319-2321) for HNO3 decomposition on glass reactors at higher temperatures. Notably, the concentration profiles of all species measured could be satisfactorily predicted by the existing [H,N,O]-mechanism with the heterogeneous initiation process.

Park, J.; Lin, M. C.

2009-10-01

227

Effect of a rigid component (tungsten alloy) on the process of formation of mixtures based on copper powder and the properties of heterogeneous unsintered compacts  

Microsoft Academic Search

We have analyzed the process of structure formation during pressing of copper-tungsten composites. We have established the\\u000a effect of the amount of the rigid phase (tungsten alloy) in the mix on the pattern of structure formation and the properties\\u000a (Young’s modulus and bending strength) of unsintered articles made from heterogeneous powder material based on copper. We\\u000a have experimentally established that

T. A. Epifantseva; Yu. N. Podrezov; D. G. Verbilo; V. G. Kayuk; I. D. Martyukhin; G. G. Serdyuk

2005-01-01

228

Time-dependent transport in heterogeneous formations of bimodal structures: 2. Results  

NASA Astrophysics Data System (ADS)

The theoretical results of part 1 [Dagan and Fiori, 2003] for modeling time-dependent, advective transport of a conservative solute in porous formations of bimodal structure are applied to illustrate the behavior of a few trajectory statistical moments as function of time, of the permeability contrast ?, and of the inclusions volume density n. The computations are carried out for circular (2D) and spherical (3D) inclusions to represent isotropic media. Advective transport is solved by studying the distortion of a thin plume, linear (2D) or planar (3D), normal to the mean velocity U and moving through a single inclusion. The deformation of the plume is determined from the residual trajectories of solute particles that are derived numerically by a quadrature. The longitudinal macrodispersivity is defined by ?L(t; n, ?) = (2U)-1dX11/dt, where X11 is the trajectories second moment in the mean flow direction. The general behavior of the time-dependent longitudinal dispersivity ?L(t; n, ?) and, in particular, its constant, large time limit are examined. The tendency of ?L to the "Fickian" limit with time depends strongly on the conductivity contrast; in particular, for low permeable inclusions (? ? 1) it may be extremely slow. It is shown that the first-order approximation in the conductivity contrast ? is of limited validity (0.3 < ? < 2). The transverse moment X22 tends asymptotically to a constant value. The analysis of the trajectory high order moments shows that the probability density function (pdf) of the solute trajectories tends to normality at large time. Similar to the "Fickian" limit the normal distribution may be reached at very large time in presence of low conductivity inclusions, with the pdf characterized by significant tailing for the trailing part of the pdf.

Fiori, A.; Dagan, G.

2003-05-01

229

Geological features indicative of processes related to the hematite formation in Meridiani Planum and Aram Chaos, Mars: a comparison with diagenetic hematite deposits in southern Utah, USA  

NASA Astrophysics Data System (ADS)

In order to understand the formation of the few but large, hematite deposits on Mars, comparisons are often made with terrestrial hematite occurrences. In southern Utah, hematite concretions have formed within continental sandstones and are exposed as extensive weathered-out beds. The hematite deposits are linked to geological and geomorphological features such as knobs, buttes, bleached beds, fractures and rings. These terrestrial features are visible in aerial and satellite images, which enables a comparison with similar features occurring extensively in the martian hematite-rich areas. The combination of processes involved in the movement and precipitation of iron in southern Utah can provide new insights in the context of the hematite formation on Mars. Here we present a mapping of the analogue geological and geomorphological features in parts of Meridiani Planum and Aram Chaos. Based on mapping comparisons with the Utah occurrences, we present models for the formation of the martian analogues, as well as a model for iron transport and precipitation on Mars. Following the Utah model, high albedo layers and rings in the mapped area on Mars are due to removal or lack of iron, and precipitation of secondary diagenetic minerals as fluids moved up along fractures and permeable materials. Hematite was precipitated intraformationally where the fluid transporting the reduced iron met oxidizing conditions. Our study shows that certain geological/geomorphological features can be linked to the hematite formation on Mars and that pH differences could suffice for the transport of the iron from an orthopyroxene volcanoclastic source rock. The presence of organic compounds can enhance the iron mobilization and precipitation processes. Continued studies will focus on possible influence of biological activity and/or methane in the formation of the hematite concretions in Utah and on Mars.

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

2004-10-01

230

Marine Geological Discoveries  

NSDL National Science Digital Library

This site by a Norwegian researcher features descriptions of marine geological formations: pockmarks, mud volcanoes, deep-water coral reefs, and gas hydrates. Using ROV technology, he has taken photos of these deep seafloor features, and compares them to geological structures seen on land, and even on the moon.

231

Probabilistic risk assessment for CO2 storage in geological formations: robust design and support for decision making under uncertainty  

NASA Astrophysics Data System (ADS)

CO2 storage in geological formations is currently being discussed intensively as a technology for mitigating CO2 emissions. However, any large-scale application requires a thorough analysis of the potential risks. Current numerical simulation models are too expensive for probabilistic risk analysis and for stochastic approaches based on brute-force repeated simulation. Even single deterministic simulations may require parallel high-performance computing. The multiphase flow processes involved are too non-linear for quasi-linear error propagation and other simplified stochastic tools. As an alternative approach, we propose a massive stochastic model reduction based on the probabilistic collocation method. The model response is projected onto a orthogonal basis of higher-order polynomials to approximate dependence on uncertain parameters (porosity, permeability etc.) and design parameters (injection rate, depth etc.). This allows for a non-linear propagation of model uncertainty affecting the predicted risk, ensures fast computation and provides a powerful tool for combining design variables and uncertain variables into one approach based on an integrative response surface. Thus, the design task of finding optimal injection regimes explicitly includes uncertainty, which leads to robust designs of the non-linear system that minimize failure probability and provide valuable support for risk-informed management decisions. We validate our proposed stochastic approach by Monte Carlo simulation using a common 3D benchmark problem (Class et al. Computational Geosciences 13, 2009). A reasonable compromise between computational efforts and precision was reached already with second-order polynomials. In our case study, the proposed approach yields a significant computational speedup by a factor of 100 compared to Monte Carlo simulation. We demonstrate that, due to the non-linearity of the flow and transport processes during CO2 injection, including uncertainty in the analysis leads to a systematic and significant shift of predicted leakage rates towards higher values compared with deterministic simulations, affecting both risk estimates and the design of injection scenarios. This implies that, neglecting uncertainty can be a strong simplification for modeling CO2 injection, and the consequences can be stronger than when neglecting several physical phenomena (e.g. phase transition, convective mixing, capillary forces etc.). The authors would like to thank the German Research Foundation (DFG) for financial support of the project within the Cluster of Excellence in Simulation Technology (EXC 310/1) at the University of Stuttgart. Keywords: polynomial chaos; CO2 storage; multiphase flow; porous media; risk assessment; uncertainty; integrative response surfaces

Oladyshkin, Sergey; Class, Holger; Helmig, Rainer; Nowak, Wolfgang

2010-05-01

232

Reservoir heterogeneity and hydrocarbon production in mixed dolomitic-clastic sequence: Escandalosa Formation, Barinas-Apure basin, southwestern Venezuela  

SciTech Connect

Widespread dedolomitization and differential leaching occur in the Turonian O Member of the Escandalosa Formation, Barinas-Apure basin. Within this dolostone-dominated succession, calcite was developed through a dedolomitization process occurring in deeply buried dolomitized lime sediments previously deposited on a carbonate platform as well as dedolomitization on the associated glauconitic-quartzose sandstones of small-scale channels that scoured the platform. The dolomitized intervals have a strata-bound nature, and their original fabric is totally obliterated. The dolomitization process generated a sucrose-textured mosaic of saddle dolomite. Initial dolomite was of the scattered type, but progressive replacement of the host produced a mosaic dolostone with both idiotopic and xenotopic textures. A general increase occurred in the iron and manganese content, and goethite was exsolved from the curved rhombs of saddle dolomite. Calcite usually postdates dolomitization, except in the highly fossiliferous packstones; calcite veins develop in both dolostones and limestones. Leaching is restricted essentially to glauconitic sandstones where calcite and some clay have been leached. This has produced very low intercrystalline porosity within the dolostones and partially dissolved, corroded and floating grains with oversized pores in the sandstones. These sandy intervals exhibit maximum potential for hydrocarbon storage, due to contrasting diagenetic influence associated with reservoir heterogeneity.

Escalona, N.; Abud, J.

1989-03-01

233

Modeling Geologic Time  

NSDL National Science Digital Library

In this activity students convert major events in Earth history from years before present into scale distances. After a list of events and their scale distances have been formulated, students construct a geologic time scale on 5 meters of adding machine paper, beginning with the formation of the Earth. Students will investigate change through geologic time; design, construct and interpret a model of geologic time; relate major events in Earth history to the geologic time scale; and compare and relate the span of Earth history to events of historical time and of the human lifetime. Some sample events and their approximate relative ages are included.

Firebaugh, James

234

Leveraging Regional Exploration to Develop Geologic Framework for CO2 Storage in Deep Formations in Midwestern United States  

Microsoft Academic Search

Obtaining subsurface data for developing a regional framework for geologic storage of CO can require drilling and characterization in a large number of deep wells, especially in areas with limited pre-existing data. One approach for achieving this objective, without the prohibitive costs of drilling costly standalone test wells, is to collaborate with the oil and gas drilling efforts in a

Neeraj Gupta

2009-01-01

235

Strontium isotopes, a window to the past: researching geological formations at Mount Wapta in the Canadian Rocky Mountains  

Microsoft Academic Search

Variations in the isotopic composition of an element are used as a tool to investigate geological processes. In this study, the variations in the 87 Sr\\/ 86 Sr isotope amount ratio are measured in carbonate minerals to interpret the extent of hydrothermal fluid-rock interactions at a Middle Cambrian site. Although the samples were from different types of altered limestone, those

Michael Wieser

236

The Impact of Geologic Heterogeneity on Stream Temperatures in the McKenzie River, Oregon: Implications for Climate Change and Land Use  

NASA Astrophysics Data System (ADS)

Stream temperature is recognized as an important component of water quality for aquatic life; less well understood is how the regional geologic setting controls stream temperature regimes. The McKenzie River watershed in western Oregon exhibits significant differences in geology and rock age between two contiguous volcanic provinces: the Plio-Pleistocene High Cascades and the Tertiary Western Cascades. Streamflow regimes from spring-fed streams originating in basins underlain by fractured and permeable High Cascade rocks have more gradual recession curves and higher baseflow unit discharges than surface-flow dominated Western Cascade streams. We examined corresponding differences in temperature between these two regions. Using spatial regime regressions, we analyzed stream temperature data from 56 sites within the McKenzie watershed. Streams with a majority contributing area composed of High Cascade rocks are colder and are less sensitive to air temperature fluctuations than Western Cascade streams during the July-September baseflow period. Based on site-specific air-stream temperature regressions, High Cascade spring-fed streams are less likely, given future air temperature increases, to exceed EPA stream temperature recommendations for chinook salmon and bull trout habitat. Finally, stream temperature for four surface-dominated and four spring-fed streams was modeled using a predictive heat budget model \\(SSTemp\\) to examine potential effects of a clearcut on stream temperatures. Model results show that spring-fed streams were less affected by this land use simulation than surface-dominated streams. However, slight perturbations to spring-fed streams may have cumulative effects on downstream reaches.

Farrell, M. J.; Tague, C.; Grant, G. E.; Jefferson, A.; Lewis, S. L.

2004-05-01

237

Heterogeneous distribution of solar and cosmogenic noble gases in CM chondrites and implications for the formation of CM parent bodies  

NASA Astrophysics Data System (ADS)

Distribution of solar, cosmogenic, and primordial noble gases in thin slices of Murchison, Murray, and Nogoya CM carbonaceous chondrites was determined by the laser microprobe analysis so as to put some constraints on the parent-body processes in the CM chondrite formation. The main lithological units of the three meteorite slices were located by electron microscope observations and classified into clastic matrix and clasts of primary accretionary rocks (PARs) based on the classification scheme of texture of CM chondrites. All sample slices contain both clastic matrix and PARs. Clastic matrix shows a comminuted texture formed by fragmentation and mechanical mixing of rocks due to impacts, whereas PARs preserve the original textures prior to the mechanical disruption. Solar-type noble gases are detected in all sample slices. They are located preferentially in clastic matrix. The distribution of solar gases is similar to that in ordinary chondrites where these gases reside in clastic dark portions of these meteorites. The heterogeneous distribution of solar gases in CM chondrites suggests that these gases were acquired not in a nebular accretion process but in parent body processes. Solar energetic particles (SEP) are predominant in CM chondrites. The low abundance of low energy solar wind (SW) component relative to SEP suggests preferential loss of SW from minerals comprising the clastic matrix, due to aqueous alteration in the parent bodies. Cosmogenic noble gases are also enriched in some portions in clastic matrix, indicating that some parts of clastic matrix were exposed to solar and galactic cosmic rays prior to the final consolidation of the CM parent bodies. Primordial noble gases are rich in fine-grained rims around chondrules in all three meteorites. However, average concentrations of heavy primordial gases in the rims differ among meteorites and correlate inversely to the degree of aqueous alteration that the meteorites have experienced. This appears to have been caused by aqueous alteration reactions between fluids and carbonaceous carrier phases of noble gases.

Nakamura, Tomoki; Nagao, Keisuke; Metzler, Knut; Takaoka, Nobuo

1999-01-01

238

Methods and apparatus for measurement of the resistivity of geological formations from within cased wells in presence of acoustic and magnetic energy sources  

DOEpatents

Methods and apparatus are provided for measuring the acoustically modulated electronic properties of geological formations and cement layers adjacent to cased boreholes. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. Voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the leakage current conducted into formation in the vicinity of those electrodes. Simultaneously subjecting the casing and formation to an acoustic source acoustically modulates the leakage current measured thereby providing a measure of the acoustically modulated electronic properties of the adjacent formation. Similarly, methods and apparatus are also described which measure the leakage current into formation while simultaneously subjecting the casing to an applied magnetic field which therefore allows measurement of the magnetically modulated electronic properties of the casing and the adjacent formation.

Vail, III, William B. (Bothell, WA)

1991-01-01

239

Geologic mapping as a method for the construction of a detailed and testable lithostratigraphic model for the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona  

NASA Astrophysics Data System (ADS)

The Upper Triassic Chinle Formation in Petrified Forest National Park represents some of the most intensively studied Upper Triassic strata in western North America. Five stratigraphic members are exposed within the park, from oldest to youngest: the Mesa Redondo, Blue Mesa, Sonsela, Petrified Forest, and Owl Rock Members. Despite numerous stratigraphic studies of the Chinle Formation and two attempts at mapping the park over the past sixty years, sandstone marker beds in the Sonsela Member at the north and south ends of the park were still poorly mapped and correlated. Studies in the years 2002 and 2006 claimed that two sandstones which previous workers had considered to lie at different stratigraphic levels (the Jasper Forest Bed and the Flattops One sandstones in the Martha’s Butte beds) were actually correlative. This correlation resulted in a three-part division of the Sonsela Member and had a major impact on vertebrate biostratigraphy. In a recent attempt to resolve confusions regarding Chinle Formation lithostratigraphy and biostratigraphy, we have completely walked out lithologic contacts through most of the park. The resulting new geologic map, revised lithostratigraphic model, and associated data resolves the 2002 and 2006 miscorrelations by demonstrating that the Jasper Forest Bed capping Blue Mesa and Agate Mesa and Flattops One sandstones (Martha’s Butte beds) are stratigraphically distinct, resulting in a thicker and more complex five-part model for the Sonsela Member, and considerably modifying the vertebrate biostratigraphy. New geologic mapping also resulted in a detailed lithostratigraphic framework for the northern park which has previously been poorly understood, and several important new marker beds, including a purple-gray bed that represents the base of the Owl Rock Member. The revised geologic map is an ArcGIS product that includes an updated lithostratigraphic model for the Chinle Formation, fossil localities, and hyperlinks to labeled photographs of measured sections. A pre-existing ArcGIS product created by workers at Northern Arizona University was used for the creation of this map and thus the final product includes some mapping, mostly Quaternary alluvium, dunes, and sandsheets, from that study. The cumulative effect of these revisions is to emphasize the importance of thoroughly exploring stratigraphic contacts, extensively documenting lithostratigraphic models, making georeferenced GIS maps, and accurately locating critical fossil localities. These methods and the new map make lithostratigraphic, biostratigraphic, and paleoecologic and paleoclimate models scientifically testable to future researchers at this classic Chinle Formation location.

Skinner, L. A.; Martz, J. W.; Parker, W.; Raucci, J.; Umhoefer, P. J.

2010-12-01

240

The moments of the breakthrough curves of instantaneously and kinetically sorbing solutes in heterogeneous geologic media: Prediction and parameter inference from field measurements  

NASA Astrophysics Data System (ADS)

This paper presents a concise methodology for estimating the moments of the breakthrough curves for tracers and reactive solutes in heterogeneous aquifers. Under some conditions these are also the temporal or travel time moments between a source and a given destination downstream. The temporal moments of tracers as well as instantaneously or kinetically sorbing solutes, characterized by linear isotherms, are expressed in terms of a few parameters which characterize the chemical reactions and the spatial distribution and correlation structure of the hydraulic conductivity. The chemical reaction parameters are assumed to be homogeneous. The estimated moments can also be made conditional to field measurements. Applications for the case of uniform mean flow are presented, but the general approach can be applied for other flow regimes such as injection-pumping well doublets. Physical and chemical nonequilibrium processes are represented by mobile-immobile domains and two-site models, respectively. The estimated temporal moments can be used for both predictive purposes as well as for interpretation of field experiments. These two objectives are pursued in this paper. A significant advantage of the solution is that it does not require the assumptions of Gaussianity or log Gaussianity of the travel times. Throughout the discussion the combined and relative effects of the mass transfer and kinetic parameters and the spatial variability of the conductivity on the travel time moments are evaluated.

Rubin, Yoram; Cushey, Mark A.; Wilson, Amy

1997-11-01

241

Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico-stratigraphic hierarchy and cycle stacking facies distribution, and interwell-scale heterogeneity: Grayburg Formation, New Mexico. Final report  

SciTech Connect

The Grayburg Formation (middle Guadalupian) is a major producing interval in the Permian Basin and has yielded more than 2.5 billion barrels of oil in West Texas. Grayburg reservoirs have produced, on average, less than 30 percent of their original oil in place and are undergoing secondary and tertiary recovery. Efficient design of such enhanced recovery programs dictates improved geological models to better understand and predict reservoir heterogeneity imposed by depositional and diagenetic controls. The Grayburg records mixed carbonate-siliciclastic sedimentation on shallow-water platforms that rimmed the Delaware and Midland Basins. Grayburg outcrops in the Guadalupe and Brokeoff Mountains region on the northwest margin of the Delaware Basin present an opportunity to construct a detailed, three-dimensional image of the stratigraphic and facies architecture. This model can be applied towards improved description and characterization of heterogeneity in analogous Grayburg reservoirs. Four orders of stratigraphic hierarchy are recognized in the Grayburg Formation. The Grayburg represents a long-term composite sequence composed of four high-frequency sequences (HFS 1-4). Each HFS contains several composite cycles comprising two or more cycles that define intermediate-scale transgressive-regressive successions. Cycles are the smallest scale upward-shoaling vertical facies successions that can be recognized and correlated across various facies tracts. Cycles thus form the basis for establishing the detailed chronostratigraphic correlations needed to delineate facies heterogeneity.

Barnaby, R.J.; Ward, W.B.; Jennings, J.W. Jr.

1997-06-01

242

Geological images  

NSDL National Science Digital Library

This site from Marli Bryant Miller, a professor at the University of Oregon, presents images of geological features from around the world. Photographs of glacial features, igneous and metamorphic rocks and processes, and structural geology are featured.

Miller, Marli B.; Oregon, University O.

243

Archeological Geology  

ERIC Educational Resources Information Center

|Describes the rapid expansion of archeological geology, especially in the area of archeological excavations, where geologists use dating techniques and knowledge of geological events to interpret archeological sites. (MLH)|

Rapp, George

1977-01-01

244

Biologically Enhanced Geologic Carbon Sequestration  

Microsoft Academic Search

There are four trapping mechanisms proposed to play significant roles in the deep geologic sequestration of CO2: i) formation trapping, ii) capillary trapping, iii) solubility trapping, and iv) mineral trapping. Our research has shown that microbial biofilms are capable of enhancing formation trapping, solubility trapping, and mineral trapping under conditions found in brine aquifers targeted for geologic carbon sequestration. We

Robin Gerlach; Andrew C. Mitchell; Lee H. Spangler; Al B. Cunningham

2010-01-01

245

Structural Geology  

NSDL National Science Digital Library

Created by the University of Nebraska-Lincoln, this site describes the basics of structural geology with text and images. The page includes the discussion of stress, strain, strike and dip, faults, folds, mountain building, erosion, economic geology, and environmental geology. This is a nice introduction to the basic topics in geology. Images from the field help to enhance the topics on the site. Instructors can use this resource to help create or simply enhance their curriculum.

2009-05-21

246

Inversion of synthetic geodetic data for dip-slip faults: clues to the effects of lateral heterogeneities and data distribution in geological environments typical of the Apennines (Italy)  

NASA Astrophysics Data System (ADS)

The inversion of geodetic data to obtain earthquake parameters is often performed by assuming that the medium is isotropic, elastic and either homogeneous or layered. The layered medium often offers the best estimate of the structure of the crust; however, predicted displacements and observed data may differ beyond the measurement errors. The slip distribution on the fault plane is usually obtained by dividing the best uniform slipping fault into an arbitrarily large number of subfaults and minimizing a cost function that includes a smoothness (Laplacian) term and a data misfit term. The smoothing factor controls the trade-off between the smoothness and the goodness-of-fit. The main focus of this work is the determination and effect of the smoothing parameter. We conducted several inversion tests of noiseless synthetic surface displacement due to faults embedded in media with properties consistent with the geology of the Central Apennines (Italy), where the 2009 April 6, L'Aquila earthquake occurred. We used the following three-step procedure: (i) global optimization with no smoothness constraint for a fault divided into a small number of equally sized equal-rake subfaults; (ii) selection of the best fault parameters using information criteria and (iii) evaluation of the slip amplitude distribution on an expanded fault after choosing the smoothing factor from trade-off curves or from cross-validation for different numbers of subfaults. We show that all of the fault features obtained by the inversion procedure, including the slip distribution, agree with those (`true') used in the forward modelling when the data cover the majority of the displacement field. Notable departures from the true slip distribution occur when a suboptimal smoothing factor (obtained from the trade-off curves or cross-validation) is used. If different crustal stratifications are used in the inversions, the best results are obtained for the stratification that is the closest to the true crustal structure. When we use more realistic GPS distributions, prominent spurious slip patches can be obtained. Modellers should use synthetic tests and sensitivity analyses as an initial step in the data inversion for source parameters.

Amoruso, A.; Barba, S.; Crescentini, L.; Megna, A.

2013-02-01

247

Structural and stratigraphic evolution of the central Mississippi Canyon area: Interaction of salt tectonics and slope processes in the formation of engineering and geologic hazards  

NASA Astrophysics Data System (ADS)

Approximately 720 square miles of digital 3-dimensional seismic data covering the eastern Mississippi Canyon area, Gulf of Mexico, continental shelf was used to examine the structural and stratigraphic evolution of the geology in the study area. The analysis focused on salt tectonics and sequence stratigraphy to develop a geologic model for the study area and its potential impact on engineering and geologic hazards. Salt in the study area was found to be established structural end-members derived from shallow-emplaced salt sheets. The transition from regional to local salt tectonics was identified through structural deformation of the stratigraphic section on the seismic data and occurred no later than ˜450,000 years ago. From ˜450,000 years to present, slope depositional processes have become the dominant geologic process in the study area. Six stratigraphic sequences (I-VI) were identified in the study area and found to correlate with sequences previously defined for the Eastern Mississippi Fan. Condensed sections were the key to the correlation. The sequence stratigraphy for the Eastern Mississippi Fan can be extended ˜28 miles west, adding another ˜720 square miles to the interpreted Fan. A previously defined channel within the Eastern Fan was identified in the study area and extended the channel ˜28 miles west. Previous work on the Eastern Fan identified the source of the Fan to be the Mobile River; however, extending the channel west suggests the sediment source to be from the Mississippi River, not the Mobile River. Further evidence for this was found in ponded turbidites whose source has been previously established as the Mississippi River. Ages of the stratigraphic sequences were compared to changes in eustatic sea level. The formation stratigraphic sequences appear decoupled from sea level change with "pseudo-highstands" forming condensed sections during pronounced Pleistocene sea level lowstands. Miocene and Pleistocene depositional analogues suggest the location of the shifting Mississippi River Pleistocene depocenter is a more dominant influence on sequence formation. Thus, the application of traditional sequence interpretation with respect to sea level change should be reconsidered to also account for the shifting depocenter for both the study area as well as the broader Eastern Mississippi Fan.

Brand, John Richard

248

Geologic Map Database of Texas  

USGS Publications Warehouse

The purpose of this report is to release a digital geologic map database for the State of Texas. This database was compiled for the U.S. Geological Survey (USGS) Minerals Program, National Surveys and Analysis Project, whose goal is a nationwide assemblage of geologic, geochemical, geophysical, and other data. This release makes the geologic data from the Geologic Map of Texas available in digital format. Original clear film positives provided by the Texas Bureau of Economic Geology were photographically enlarged onto Mylar film. These films were scanned, georeferenced, digitized, and attributed by Geologic Data Systems (GDS), Inc., Denver, Colorado. Project oversight and quality control was the responsibility of the U.S. Geological Survey. ESRI ArcInfo coverages, AMLs, and shapefiles are provided.

Stoeser, Douglas B.; Shock, Nancy; Green, Gregory N.; Dumonceaux, Gayle M.; Heran, William D.

2005-01-01

249

On the formation of breakthrough curves tailing during convergent flow tracer tests in three-dimensional heterogeneous aquifers  

NASA Astrophysics Data System (ADS)

Anomalous transport in advection-dominated convergent flow tracer tests can occurs due to small-scale heterogeneities in aquifer hydraulic properties. These result in fluctuations of the groundwater velocity field and complex connectivity patterns between injection and extraction wells. While detailed characterization of heterogeneity is often not possible in practice, a proper understanding of what fundamental physical mechanisms can give rise to macroscopic behaviors that are measurable is essential for proper upscaling of solute transport processes. We analyze here how heavy-tailed breakthrough curves can arise in radially convergent flow to a well. The permeability fields are three-dimensional multi-Gaussian fields with varying statistical geometry and degrees of heterogeneity. We consider transport of conservative tracers from multiple injection locations by varying distance and angle from the extraction well. Anomalous power law tailing in breakthrough curves is attributed to a variety of features including the initial vertical stratification of the solute that arises due to a flux-weighted injection, the injection distance to the well relative to the depth of the aquifer, and the statistics of the heterogeneity field as defined by the correlation length and variance of the permeability. When certain conditions cooccur for a given injection, such as strong connectivity contrasts between aquifer layers, injection distances comparable to the horizontal heterogeneity integral scales, and large global variances, breakthrough curves tend to scale as a PL with unit slope at late time. These findings offer new insights to understand what physical processes must be understood to develop and choose appropriate upscaling approaches that might reproduce such anomalous transport in heterogeneous advection-dominated systems.

Pedretti, D.; Fernã Ndez-Garcia, D.; Bolster, D.; Sanchez-Vila, X.

2013-07-01

250

National Geologic Map Database  

NSDL National Science Digital Library

The National Geologic Map Database (NGMDB) is an Internet-based system for query and retrieval of earth-science map information, created as a collaborative effort between the USGS and the Association of American State Geologists. Its functions include providing a catalog of available map information; a data repository; and a source for general information on the nature and intended uses of the various types of earth-science information. The map catalog is a comprehensive, searchable catalog of all geoscience maps of the United States, in paper or digital format. It includes maps published in geological survey formal series and open-file series, maps in books, theses and dissertations, maps published by park associations, scientific societies, and other agencies, as well as publications that do not contain a map but instead provide a geological description of an area (for example, a state park). The geologic-names lexicon (GEOLEX) is a search tool for lithologic and geochronologic unit names. It now contains roughly 90% of the geologic names found in the most recent listing of USGS-approved geologic names. Current mapping activities at 1:24,000- and 1:100,000-scale are listed in the Geologic Mapping in Progress Database. Information on how to find topographic maps and list of geology-related links is also available.

1997-01-01

251

Mining geology of the Pond Creek seam, Pikeville Formation, Middle Pennsylvanian, in part of the Eastern Kentucky Coal Field, USA  

USGS Publications Warehouse

The Pond Creek seam is one of the leading producers of coal in the Eastern Kentucky Coal Field. The geologic factors that affect mining were investigated in several underground mines and categorized in terms of coal thickness, coal quality, and roof control. The limits of mining and thick coal are defined by splitting along the margin of the coal body. Within the coal body, local thickness variation occurs because of (1) leader coal benches filling narrow, elongated depressions, (2) rider coal benches coming near to or merging with the main bench, (3) overthrust coal benches being included along paleochannel margins, (4) cutouts occuring beneath paleochannels, and (5) very hard and unusual rock partings occuring along narrow, elongated trends. In the study area, the coal is mostly mined as a compliance product: sulfur contents are less than 1% and ash yields are less than 10%. Local increases in sulfur occur beneath sandstones, and are inferred to represent post-depositional migration of fluids through porous sands into the coal. Run-of-mine quality is also affected by several mine-roof conditions and trends of densely concentrated rock partings, which lead to increased in- and out-of-seam dilution and overall ash content of the mined coal. Roof control is largely a function of a heterolithic facies mosaic of coastal-estuarine origin, regional fracture trends, and unloading stress related to varying mine depth beneath the surface. Lateral variability of roof facies is the rule in most mines. The largest falls occur beneath modern valleys and parallel fractures, along paleochannel margins, within tidally affected 'stackrock,' and beneath rider coals. Shale spalling, kettlebottoms, and falls within other more isolated facies also occur. Many of the lithofacies, and falls related to bedding weaknesses within or between lithofacies, occur along northeast-southwest trends, which can be projected in advance of mining. Fracture-related falls occur independently of lithofacies trends along northwest-southeast trends, especially beneath modern valleys where overburden thickness decreases sharply. Differentiating roof falls related to these trends can aid in predicting roof quality in advance of mining.The Pond Creek-Lower Elkhorn seam has been an important exploration target because it typically has very low sulfur contents and ash yields. Geologic research in several large Pond Creek mines suggested variability in roof quality and coal thickness. Due to mine access, geologic problems encountered during mining are documented and described.

Greb, S. F.; Popp, J. T.

1999-01-01

252

An integrated multi-scale hydrogeological model for performance and safety assessment of French geological high level and long live radwaste disposal in clay formation  

NASA Astrophysics Data System (ADS)

A deep geological repository of high level and long live radwaste requires sound understanding of the far field and near field groundwater flow and transport properties. Andra, French National radioactive waste management Agency is developing since last 15 years, an integrated multi-scale hydrogeological model of whole Paris basin of 200'000 Km2 area (regional scale) to produce a regional flow field associated to groundwater behavior. It includes locally the Meuse / Haute Marne clay site of about 250 Km2 area in the eastern part of Paris basin that was chosen for the emplacement of a repository. Callovo-Oxfordian as host formation is a clay layer characterized by very low permeability, a mean thickness of 130 m at about 500 m depth and is embedded by calcareous formations as aquifers (Dogger and Oxfordian). The hydrogeological conceptual model is based on stratigraphic and petrophysic modeling of the Paris basin and is accounting for the sound structural, geological, hydrogeological and geochemical data in an integrated way. At Paris basin scale, the model is a multilayer system of 27 layers (hydrogeological units) from Trias to Tertiary. A refinement at local scale of the site defines 27 hydro-geological units from Trias to Portlandian within an area of 1800 Km2. Based on sound data acquisition from borehole and seismic campaigns performed by Andra, regional faults, minor and diffuse fractures are considered. A structural and petrophysical representation of the transition zone between the Paris basin scale and site scale, as well as a better handling of surface flow boundary conditions are considered. Finite element flow and transport simulator Ground Water code (GW) is used to solve for groundwater flow at steady-state in a 1.8 Million nodes model, considering current climatic conditions. The model is calibrated against about 1250 hydraulic head measurements, and results in maximum absolute hydraulic head differences of 20 meters at the regional scale and 5 meters at the local scale. The calibrated reference model includes transmissive major faults as well as structures acting as barrier to flow. Advective-dispersive age solutions are also carried out and compared to available age dates of pore water within the two main calcareous aquifers (Dogger and Oxfordian) that embed Callovo-Oxfordian host formation, to consolidate calibration of flow and to analyze internal water mixing processes and hydraulic behavior of major faults. Lifetime expectancy solutions combined with age solutions are also used to map in the 3-D space the low- and high-speed flow zones at the local scale.

Benabderrahmane, H.; Cornaton, F. J.; Kerrou, J.

2009-12-01

253

A heterogeneous layered bifunctional catalyst for the integration of aerobic oxidation and asymmetric C-C bond formation.  

PubMed

The design and synthesis of a heterogeneous bifunctional chiral catalyst for the sequential aerobic oxidation-asymmetric Michael reactions between primary allylic alcohols and dibenzyl malonate are described. Interestingly, we found that layering bimetallic nanoparticles over the organocatalyst, within the chiral composite material, is crucial for catalytic activity. PMID:24036576

Miyamura, Hiroyuki; Choo, Gerald C Y; Yasukawa, Tomohiro; Yoo, Woo-Jin; Kobayashi, Shu

2013-10-01

254

Participation in Heterogeneous Communities  

Microsoft Academic Search

This paper studies what determines group formation and the degree of participation when the population is heterogeneous, both in terms of income and race or ethnicity. We are especially interested in whether and how much the degree of heterogeneity in communities influences the amount of participation in different types of groups. Using survey data on group membership and data on

Eliana La Ferrara

2000-01-01

255

Participation in Heterogeneous Communities  

Microsoft Academic Search

This paper studies both theoretically and empirically the determinants of group formation and of the degree of participation when the population is heterogeneous, both in terms of income and race or ethnicity. We are especially interested in whether and how much the degree of heterogeneity in communities influences the amount of participation in different types of groups. Using survey data

Alberto Alesina; Eliana La Ferrara

1999-01-01

256

Coupling geothermal energy capture with carbon dioxide sequestration in permeable, porous geologic formations II: Numerical modeling and preliminary results  

NASA Astrophysics Data System (ADS)

Carbon dioxide (CO2) sequestration in deep saline aquifers and exhausted oil fields has been widely considered as a means for reducing CO2 emissions to the atmosphere as a counter-measure to global warming. However, rather than treating CO2 as a waste fluid in need of permanent disposal, it could additionally be used as a working fluid in geothermal energy capture as its thermodynamic properties suggest it transfers heat more efficiently than water. Therefore, utilizing CO2 may permit more widespread implementation of geothermal power systems. Here, we present numerical modeling results of coupled CO2 injection into a brine and heat transfer in geothermal reservoirs under conditions relevant for both CO2 sequestration and geothermal electricity generation. In particular, we examine subsurface flow and heating of the sequestered CO2, cooling of the geothermal reservoir, and changes in pore-fluid pressures under a variety of generalized CO2 injection and production scenarios and reservoir characteristics. While additional research is required, modeling results at present suggest that geologic reservoirs with CO2 as the heat mining fluid would be viable geothermal energy sources for electric power production for decades, potentially even in regions with relatively low geothermal temperatures and heat flow rates.

Randolph, J. B.; Saar, M. O.

2009-12-01

257

Coupling geothermal energy capture with carbon dioxide sequestration in permeable, porous geologic formations I: Overview and discussion  

NASA Astrophysics Data System (ADS)

Carbon dioxide (CO2) sequestration in deep saline aquifers and exhausted oil fields has been widely considered as a means for reducing CO2 emissions to the atmosphere as a counter-measure to global warming. However, rather than treating CO2 as a waste fluid in need of permanent disposal, it could additionally be used as a working fluid in geothermal energy capture as its thermodynamic properties suggest it transfers heat more efficiently than water. Therefore, using CO2 as the working fluid in geothermal power systems may permit more widespread utilization of geothermal energy, whether regional geothermal temperatures and heat flow rates are low, intermediate, or high. In addition, CO2 emissions from electricity production are reduced through both geologic CO2 sequestration and displacement of hydrocarbon fuels via use of renewable geothermal energy. Furthermore, geothermal power plants are quite scalable and can provide both on-demand peak and base-load power. Here, we discuss the merits and limitations of a CO2-based geothermal system and present results of early-stage calculations regarding geothermal power plant efficiencies and energy production rates when CO2, rather than water, is used as a working fluid.

Saar, M. O.; Randolph, J. B.

2009-12-01

258

Travel time distributions under convergent radial flow in heterogeneous formations: Insight from the analytical solution of a stratified model  

NASA Astrophysics Data System (ADS)

We analyze conservative solute transport under convergent flow to a well in perfectly stratified porous media, in which the hydraulic conductivity is treated as a random spatial function along the vertical direction (K(z)). The stratified model provides a rare exception of an exact analytical solution of travel time distributions in the proximity of pumping wells, and it is used here to obtain insights about ergodic and nonergodic transport conditions under nonuniform flow conditions. In addition, it provides a benchmark for numerical models aiming to correctly reproduce convergent flow transport in heterogeneous media, such as indicating the minimum number of layers required to obtain ergodic travel time distributions using only one model realization. The model provides important insights about the shape of the depth-integrated concentrations over time measured at the well (breakthrough curves, BTCs), which are usually applied to obtain transport parameters of the subsurface. It can be applied to any degree of system's heterogeneity and using either resident or flux-weighted injection modes. It can be built using different probabilistic distributions of K. In our analysis, we consider a log-normal K distribution, and the results indicate that, especially for highly heterogeneous systems, described by the log-K variance (?Y2), the minimum number of layers required for from one model simulation to reproduce ergodic travel time distributions can be prohibitively high, e.g., above 106 for ?Y2=8 considering flux-weighted injections. This issue poses serious concerns for numerical applications aiming to simulate transport in the proximity of pumping wells. In addition, this simple solution confirms that stratification can lead BTCs to display strong preferential flow and persistent, power-law-like late-time tailing. Since the latter are common phenomenological macroscale evidences of other microscale hydrodynamic processes than pure advection (e.g., mass-transfer), caution must be taken when inferring aquifer properties controlling the anomalous transport dynamics in heterogeneous media from BTCs fitting.

Pedretti, Daniele; Fiori, Aldo

2013-10-01

259

Lunar geology  

NASA Astrophysics Data System (ADS)

The development of a lunar geological map is traced, from the post-war period through the final Apollo mission. The impact of geological discoveries on earth on lunar geology is explained, and the use of photographs of the lunar surface to deduce its stratigraphy is described. The confirmation of the ages of various parts of the moon's surface through analysis of moon rocks is also discussed.

Shoemaker, E.

260

Evaluation of the geological relationships to gas hydrate formation and stability. Progress report, June 16--September 30, 1988  

SciTech Connect

The summaries of regional basin analyses document that potentially economic accumulations of gas hydrates can be formed in both active and passive margin settings. The principal requirement for gas hydrate formation in either setting is abundant methane. Passive margin sediments with high sedimentation rates and sufficient sedimentary organic carbon can generate large quantities of biogenic methane for hydrate formation. Similarly, active margin locations near a terrigenous sediment source can also have high methane generation potential due to rapid burial of adequate amounts of sedimentary organic matter. Many active margins with evidence of gas hydrate presence correspond to areas subject to upwelling. Upwelling currents can enhance methane generation by increasing primary productivity and thus sedimentary organic carbon. Structural deformation of the marginal sediments at both active and passive sites can enhance gas hydrate formation by providing pathways for migration of both biogenic and thermogenic gas to the shallow gas hydrate stability zone. Additionally, conventional hydrocarbon traps may initially concentrate sufficient amounts of hydrocarbons for subsequent gas hydrate formation.

Krason, J.; Finley, P.

1988-12-31

261

Geological and geochemical controls on the formation and distribution of supergiant gas fields in the Russian sedimentary basins  

SciTech Connect

The West Siberian, Barents Sea and Northern Caspian sedimentary basins are the most prolific Russian gas producing regions and include 15 supergiant gas fields each of them content identified gas reserves between 1 x 10[sup 12] m[sup 3] to 11 x 10[sup 12] m[sup 3]. They are Urengoi, Yarnburg, Bovanenkov, Zapoljarnoye, Medvezhie, Charasavey, Kruzenshtern, N.Urengoi, S.Tambey, S.Russkoye, Rusanov, Shtockmanov, Lunin, Astrachan and Orenburg. The gas reserves in these basins exceed 70 x 10[sup 12] m[sup 3] and about 65% of them concentrated in supergiant fields. Among the geological prerequisites for largest gas accumulations note big size of trap (Urengoi 40x300 km[sup 2]; Astrachan l80x200 km[sup 2]), anticline type of tectonic structure (swell, megaswell, dome, arch) with amplitude from 110 m to 800 in. These tectonic structure were active long time include the latest period. The main gas productive reservoirs are slightly consulted non-marine sandstones of Cenomanian or Middle Jurassic ages (West Siberia and Barents Sea) or Middle Carboniferous reef carbonate buildups (Northern Caspian basin). The next geochemical parameters controlled of the gas accumulation histories: (1) West Siberia and Barents Sea regions gas genetically connect with dispersed or concentrated non-marine coal type kerogen distributed into productive complex under lower maturity conditions (before or early oil window zone). This is dry gas almost pure methane with [delta][sup 13] C[sub 1] between -44,40[per thousand]. In this case we observe widely distributed mainly sandstones reservoirs at same time gas source rocks also; (2) the Northern Caspian basin found supergiant wet gas-condensate accumulations into local distributed reef carbonate buildups. Gas source rocks is marine kerogen type II, which has a low concentration in marlaceous facies. It is gas high maturity zone.

Lopatin, N. (VNIIgeosystem, Moscow (Russian Federation))

1996-01-01

262

Geology Fieldnotes: Timpanogos National Monument, Utah  

NSDL National Science Digital Library

Timpanogos Cave National Monument, in the Wasatch Mountains, features spectacularly decorated caverns, each of which has unique colors and formations. Features of the site include park geology information, maps, photographs of cave formations, related links, and visitor information. The park geology section discusses the caves' geologic history, structural geology, and details the discovery of the Hansen and Middle Caves (by Martin, George, and Wayne Hansen) and the Timpanogos Cave (by Veral Manwill).

263

Distribution and geological significance of 17?(H)-diahopanes from different hydrocarbon source rocks of Yanchang Formation in Ordos Basin  

Microsoft Academic Search

Based on GC-MS testing data of many saturated hydrocarbon samples, 17?(H)-C30 diahopanes (C30\\u000a *) are extensively distributed in the lacustrine hydrocarbon source rocks of the Yanchang Formation in Ordos Basin, but show\\u000a remarkable differences in relative abundance among various source rocks. Generally, Chang 7 high-quality source rock (oil\\u000a shale) developed in deep lake anoxic environment shows lower C30\\u000a * content,

WenZheng Zhang; Hua Yang; LiHui Hou; Fei Liu

2009-01-01

264

California Geological Survey: Geologic Maps  

NSDL National Science Digital Library

This index provides access to a selection of geologic maps of California, as well as an overview of geologic and other mapping activities in the state. The index, which can be accessed by clicking on an interactive map of the state, contains lists of selected geologic maps in California prepared by the Regional Geologic Mapping Project (RGMP). The RGMP staff monitors the literature and collects references that contain geologic mapping that may be useful for future compilations. In addition, the site has information about Caltrans Highway Corridor Mapping, The Mineral Resources and Mineral Hazards Mapping Program, North Coast Watersheds Assessment Program, The Timber Harvesting Plan Enforcement Program, and The Seismic Hazards Mapping Program. A set of links is provided to other sources of geologic maps and map information.

265

Radiolarian biostratigraphy of the Quinn River Formation, Black Rock terrane, north-central Nevada: correlations with eastern Klamath terrane geology  

USGS Publications Warehouse

The Quinn River Formation, Black Rock terrane, Quinn River Crossing, is one of the few Nevadan sections of Permian and Triassic strata that are unaffected by Sonoman deformation. The formation consists of: 1) a basal tuff overlain by limestone and ferruginous dolomite, 2) interbedded radiolarian-bearing chert and argillite, 3) siltstone and carbonaceous shale, and 4) partly volcaniclastic rocks. All but the uppermost (barren) chert samples contain Late Permian radiolarian taxa. These radiolarians suggest that early Wordian conodonts reported from near the top of the chert and argillite unit are reworked. Poorly preserved Early(?) or Middle triassic radiolarians and Middle Triassic ammonites and pectenacid bivalves from the middle part of the volcaniclastic unit indicate the Early Triassic deposition cannot be documented at Quinn River. The ages of the Quinn River brachiopod, conodont, and radiolarian faunas resemble those of the Dekkas and Pit Formations, eastern Klamath terrane, northern California. The analogous Quinn River and eastern Klamath rock types and faunal ages, as well as similar hiatuses in their stratigraphic records, suggest that they may be lateral equivalents that formed in the same island-arc sedimentary basin. -from Authors

Blome, C. D.; Reed, K. M.

1995-01-01

266

North Cascades Geology: Geologic Time  

NSDL National Science Digital Library

This article describes the period of geologic time spanned by the rocks of the North Cascades area of Washington. Users can access a simplified geologic time scale that provides links to geologic events in the North Cascades region. These include the deposition of various terranes, periods of intrusion and metamorphism, the beginning of the Cascade volcanic arc, and periods of major glaciation. Links to related materials are also provided.

267

Modeling heterogeneous unsaturated porous media flow at Yucca Mountain.  

National Technical Information Service (NTIS)

Geologic systems are inherently heterogeneous and this heterogeneity can have a significant impact on unsaturated flow through porous media. Most previous efforts to model groundwater flow through Yucca Mountain have used stratigraphic units with homogene...

T. H. Robey

1994-01-01

268

Yellowstone Geology  

NSDL National Science Digital Library

This Yellowstone National Park website provides geological information about the Park. Links include geologic highlights, hydrothermal features, reports by park geologists, and scientists' talks (videos). A wide array of information can be found on these links and the webpage is expanding as more topics are added.

Park, Yellowstone N.

269

Physical geology  

SciTech Connect

The book integrates current thinking on processes (plate techtonics, chemical cycles, changes throughout geologic time). It is an introduction to investigations into the way the earth works, how mountains are formed, how the atmosphere, hydrosphere, crust and mantle interact with each other. Treatments on climate, paleoclimatology and landscape evolution are included, as is a discussion on how human activity affects geological interactions.

Skinner, B.; Porter, S.

1987-01-01

270

Engineering Geology  

ERIC Educational Resources Information Center

Engineering geology remains a potpourri of applied classical geology, and 1977 witnessed an upswing in demand for these services. Traditional foundation-related work was slight, but construction related to national needs increased briskly. Major cities turned to concerns of transit waste-water treatment and solid-waste disposal. (Author/MA)

Hatheway, Allen W.

1978-01-01

271

Measuring resistivity changes from within a first cased well to monitor fluids injected into oil bearing geological formations from a second cased well while passing electrical current between the two cased wells  

DOEpatents

A.C. current is conducted through geological formations separating two cased wells in an oil field undergoing enhanced oil recovery operations such as water flooding operations. Methods and apparatus are disclosed to measure the current leakage conducted into a geological formation from within a first cased well that is responsive to fluids injected into formation from a second cased well during the enhanced oil production activities. The current leakage and apparent resistivity measured within the first cased well are responsive to fluids injected into formation from the second cased well provided the distance of separation between the two cased wells is less than, or on the order of, a Characteristic Length appropriate for the problem.

Vail, W.B. III.

1993-02-16

272

Application of fracture mechanics in geological materials  

Microsoft Academic Search

Application of conventional fracture mechanics concepts to treat crack growth and failure problems in geological media is discussed in this paper. Conventional fracture mechanics methods were developed mainly for metallic materials which exhibit nonlinearity associated mainly with plasticity type responses. Thus, these are not directly applicable to geological materials whose inelastic responses originate from inherent large-scale heterogenities, microcracking, strain softening,

1991-01-01

273

RADIO-WAVE METHOD OF GEOLOGICAL MAPPING  

Microsoft Academic Search

Practical methods of using radio waves in geological mapping are considered. The history and basic principles of the method are briefly outlined. When transmitted radio waves penetrate the earth to a definite depth, they induce currents in the heterogeneous geological structures encountered (ore veins, contacts of different rocks, ground-water lenses, for example). The electromagnetic fields of these currents superimposed on

A. D. Frolov

1961-01-01

274

Geological setting of oil shales in the Permian phosphoria formation and some of the geochemistry of these rocks  

USGS Publications Warehouse

Recent studies of the Meade Peak and the Retort Phosphatic Shale Members of the Phosphoria Formation have investigated the organic carbon content and some aspects of hydrocarbon generation from these rocks. Phosphorite has been mined from the Retort and Meade Peak members in southeastern Idaho, northern Utah, western Wyoming and southwestern Montana. Organic carbon-rich mudstone beds associated with the phosphorite in these two members also were natural sources of petroleum. These mudstone beds were differentially buried throughout the region so that heating of these rocks has been different from place to place. Most of the Phosphoria source beds have been deeply buried and naturally heated to catagenetically form hydrocarbons. Deepest burial was in eastern Idaho and throughout most of the northeastern Great Basin where high ambient temperatures have driven the catagenesis to its limit and beyond to degrade or to destroy the hydrocarbons. In southwest Montana, however, burial in some areas has been less than 2 km, ambient temperatures remained low and the kerogen has not produced hydrocarbons (2). In these areas in Montana, the kerogen in the carbonaceous mudstone has retained the potential for hydrocarbon generation and the carbon-rich Retort Member is an oil shale from which hydrocarbons can be synthetically extracted. The Phosphoria Formation was deposited in a foreland basin between the Cordilleran geosyncline and the North American craton. This foreland basin, which coincides with the area of deposition of the two organic carbon-rich mudstone members of the Phosphoria, has been named the Sublett basin (Maughan, 1979). The basin has a northwest-southeast trending axis and seems to have been deepest in central Idaho where deep-water sedimentary rocks equivalent to the Phosphoria Formation are exceptionally thick. The depth of the basin was increasingly shallower away from central Idaho toward the Milk River uplift - a land area in Montana, the ancestral Rocky Mountains. The basin is composed of land areas in Colorado, the Humboldt highland in northeastern Nevada and intervening carbonate shelves in Utah and Wyoming. The phosphorites and the carbonaceous mudstones were deposited on the foreslope between the carbonate and littoral sand deposits on the shelf and the dominantly cherty mudstone sediments in the axial part of the basin. Paleomagnetic evidence indicates that in the Permian the region would have been within the northern hemispheric trade wind belt; and wind-direction studies determined from studies of sand dunes, indicate that the prevailing winds from the Milk River uplift would have blown offshore across the Phosphoria sea. Offshore winds would have carried surface water away from the shore and generated upwelling in the sea in eastern Idaho and adjacent areas in Montana, Wyoming and Utah. Prior to deposition of the Phosphoria, the region was the site of extensive deposition of shallow-water carbonate sediments. Equivalent rocks in the northern part of the basin are dominantly sandstone derived from the adjacent Milk River uplift and similar sandstone strata in the southeastern sector were derived from the ancestral Rocky Mountains uplift. Tectonic subsidence of the Sublett basin in part of the region seems to have provided a sea-floor profile favorable for upwelling circulation and the shift in deposition from regional carbonates and local sandstone into a more complex depositional pattern that included the accumulation of the mudstone-chert-phosphorite facies that comprises the Phosphoria Formation. High biological productivity and the accumulation of sapropel on the sea floor is associated with contemporary coastal upwelling (1) and similar environmental and depositional conditions are attributed to the rich accumulations of organic matter in the Phosphoria Formation. Sapropelic mudstone and phosphorite composing the Meade Peak Member are approximately 60 m thick near the center of the Sublett basin. The Meade

Maughan, E. K.

1983-01-01

275

Differences in the scale-dependence of dispersivity estimated from temporal and spatial moments in chemically and physically heterogeneous porous media  

Microsoft Academic Search

Tracer tests designed to estimate field-scale dispersivities are commonly based upon the interpretation of breakthrough curves. Implicitly, no distinction is made between these dispersivity values and those inferred by analyzing the evolution of tracer plumes. Although this assumption is reasonable in ideal homogeneous media, its applicability to complex geologic formations is unclear. Recent laboratory tracer tests in a heterogeneous test

Daniel Fernàndez-Garcia; Tissa H. Illangasekare; Harihar Rajaram

2005-01-01

276

IgG particle formation during filling pump operation: A case study of heterogeneous nucleation on stainless steel nanoparticles  

Microsoft Academic Search

This study investigated factors associated with vial filling with a positive displacement piston pump leading to formation of protein particles in a formulation of an IgG. We hypothesized that nanoparticles shed from the pump's solution-contact surfaces nucleated protein aggregation and particle formation. Vials of IgG formulation filled at a clinical manufacturing site contained a few visible particles and about 100,000

Anil K. Tyagi; Theodore W. Randolph; Aichun Dong; Kevin M. Maloney; CARL HITSCHERICH JR; John F. Carpenter

2009-01-01

277

Geology of the nahcolite deposits and associated oil shales of the Green River Formation in the Piceance Creek Basin, Colorado  

NASA Astrophysics Data System (ADS)

Stratigraphic and lithologic studies of drill cores from 10 exploratory holes reveal that five eights of the nahcolite resource, occurs as crystalline aggregates in maristone. The remainder of the resource consists of laterally continuous zones of disseminated nahcolite in maristone and beds of mixed nahcolite and halite. Sedimentologic data indicate that the maristones and associated sodium minerals were deposited by pelagic, turbiditic, and evaporitic processes in a permanent alkaline lake. Lower lake waters and sediments favored high rates of bacterial reduction of sulfate and hydrolysis of fine grained detrital silicate minerals. These processes resulted in production of bicarbonate and the formation of an authigenic suite of carbonate and silicate minerals devoid of clay and sulfate minerals. Cyclic probably seasonal, stratification is recorded by the laminated maristones and in some units of disseminated and bedded nahcolite and halite. The vertical distribution of total sulfur in the maristones is also cyclic and may be related to evaporative phases of the lake.

Dyni, J. R.

278

Nested geological modelling of naturally fractured reservoirs  

Microsoft Academic Search

Because of the multiscaled character of fracture networks and their high degree of heterogeneity, characterization and modelling of fractured reservoirs requires different techniques to the well-established geostatistical methods derived for modelling rock heterogeneity. We have developed a method to improve the geological model used as an input of fractured reservoir fluid flow simulators, either in single or dual permeability simulations,

M. C. Cacas; J. M. Daniel; J. Letouzey

2001-01-01

279

Aerosol silica as a possible candidate for the heterogeneous formation of nitric acid hydrates in the stratosphere  

NASA Astrophysics Data System (ADS)

The liquid-solid phase transitions in nanometersize HNO3/H2O solution droplets obtained on fumed silica (a counterpart of aerosol silica) have been studied with differential scanning calorimetry (DSC). “Soft” transitions, reduction in the freezing and melting temperatures, Tf and Tm, and enthalpies, ?Hf and ?Hm, are interpreted to be caused by very small size of droplets. The observed difference between ?Hf and ?Hm can serve as an evidence of temperature dependence of the enthalpy of fusion for hydrates. Freezing of droplets with stoichiometry close to nitric acid trihydrate (NAT) at temperature 4 K warmer than the ice frost point indicates that, in the stratosphere, silica particles can serve as nuclei for heterogeneous freezing of NAT.

Bogdan, A.; Kulmala, M.

280

Geologic Time  

NSDL National Science Digital Library

The Earth is very old -- 4.5 billion years or more -- according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science.

Newman, William L.

1997-01-01

281

Geologic time  

USGS Publications Warehouse

The Earth is very old 4 1/2 billion years or more according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science.

Newman, William L.

2000-01-01

282

Periods of active permafrost layer formation during the geological history of Mars: Implications for circum-polar and mid-latitude surface processes  

NASA Astrophysics Data System (ADS)

Permafrost is ground remaining frozen (temperatures are below the freezing point of water) for more than two consecutive years. An active layer in permafrost regions is defined as a near-surface layer that undergoes freeze-thaw cycles due to day-average surface and soil temperatures oscillating about the freezing point of water. A "dry" active layer may occur in parched soils without free water or ice but significant geomorphic change through cryoturbation is not produced in these environments. A wet active layer is currently absent on Mars. We use recent calculations on the astronomical forcing of climate change to assess the conditions under which an extensive active layer could form on Mars during past climate history. Our examination of insolation patterns and surface topography predicts that an active layer should form on Mars in the geological past at high latitudes as well as on pole-facing slopes at mid-latitudes during repetitive periods of high obliquity. We examine global high-resolution MOLA topography and geological features on Mars and find that a distinctive latitudinal zonality of the occurrence of steep slopes and an asymmetry of steep slopes at mid-latitudes can be attributed to the effect of active layer processes. We conclude that the formation of an active layer during periods of enhanced obliquity throughout the most recent period of the history of Mars (the Amazonian) has led to significant degradation of impact craters, rapidly decreasing the steep slopes characterizing pristine landforms. Our analysis suggests that an active layer has not been present on Mars in the last ˜5 Ma, and that conditions favoring the formation of an active layer were reached in only about 20% of the obliquity excursions between 5 and 10 Ma ago. Conditions favoring an active layer are not predicted to be common in the next 10 Ma. The much higher obliquity excursions predicted for the earlier Amazonian appear to be responsible for the significant reduction in magnitude of crater interior slopes observed at higher latitudes on Mars. The observed slope asymmetry at mid-latitudes suggests direct insolation control, and hence low atmospheric pressure, during the high obliquity periods throughout the Amazonian. We formulate predictions on the nature and distribution of candidate active layer features that could be revealed by higher resolution imaging data.

Kreslavsky, Mikhail A.; Head, James W.; Marchant, David R.

2008-02-01

283

A Primer in Lunar Geology.  

National Technical Information Service (NTIS)

Primary topics in lunar geology range from the evolution of the solar system to lunar photointerpretation, impact crater formation, and sampling to analyses on various Apollo lunar landing site geomorphologies.

P. H. Schultz R. Greeley

1974-01-01

284

Mathematical Geology.  

ERIC Educational Resources Information Center

The year 1978 marked a continued trend toward practical applications in mathematical geology. Developments included work in interactive computer graphics, factor analysis, the vanishing tons problem, universal kriging, and resource estimating. (BB)

McCammon, Richard B.

1979-01-01

285

Engineering Geology  

ERIC Educational Resources Information Center

Briefly reviews the increasing application of geologic principles, techniques and data to engineering practices in the areas of land use and zoning controls, resource management energy programs and other fields. (BR)

Lee, Fitzhugh T.

1974-01-01

286

Geologic Timeline  

NSDL National Science Digital Library

Dive into the depths of time with this Geologic Timeline. The farther you scroll down, the farther back in time you'll travel. Also, the longer a period is on this page, the longer it lasted in history!

2000-01-01

287

Schoolyard Geology  

NSDL National Science Digital Library

This set of lessons provides teachers with ideas on how to turn their schoolyards into a rich geologic experience that students will find familiar, easily accessible, and personally relevant. The three lesson plans feature materials on mapping, rock descriptions and geologic interpretations, ages of rocks, and dinosaur tracks. Lesson 1, "Map Your Schoolyard," teaches students what maps are, what they are used for, and some features used on maps (north arrow, scale bar, legend, etc.). Lesson 2, "Rock Stories," illustrates how to make geologic observations and what important properties of rocks to look for. Lesson 3, "GeoSleuth Schoolyard," teaches students that geology is a lot like detective work, in which geologists infer the sequence and timing of events by collecting evidence and making observations. Relevant California state science standards are also listed.

288

Dolomitization and neomorphism of Mississippian (Visean) upper debolt formation, Blueberry field, northeastern British Columbia: Geologic, petrologic, and chemical evidence  

SciTech Connect

Petrographic, chemical, and isotopic studies of the Mississippian (Visean) upper Debolt Formation in the Blueberry field, British Columbia, Canada, reveal that dolomitization was the result of several diagenetic events and that neomorphic alteration of these dolomites significantly modified their original chemical signatures. These studies also demonstrate how tectonics play an important role in controlling and modifying reservoir dolomites in the area. Petrographic investigations have documented two early dolomite phases, (1) early matrix dolomite and (2) pervasive dolomite, and two later generations, (3) coarse cement and (4) pseudomorphic replacement of crinoids. Early matrix dolomite occurs as small (average 25 {mu}m) subhedral to euhedral crystals that replace the matrix of carbonate mudstones, wackestones, and packstones. Petrographic evidence suggests that early matrix dolomite had a relatively early, precompaction origin, possibly from marine fluids. However, geochemical evidence indicates that later fluids have altered their original geochemical signatures. Pervasive dolomite, which forms the reservoir intercrystalline porosity, occurs with planar-s and planar-e textures. Planar-s crystals typically have a dirty appearance and exhibit homogeneous dull brown/red cathodoluminescence colors. Planar-e crystals may appear with a cloudy core and a clear rim, and under cathodoluminescence display an irregular dull brown/red core and a thin, bright red rim. Due to the spatial distribution pattern of pervasive dolomite with respect to the overlying unconformity surface, its paleogeographic distribution and close temporal relationship with meteoric diagenetic events, pervasive dolomite formed from a mixture of seawater and meteoric fluids. However, alteration of their primary chemistry by later fluids is indicated by their depleted {delta}{sup 18}O values and radiogenic {sup 87}Sr/{sup 86}Sr ratios.

Durocher, S.; Al-Aasm, I.S. [Univ. of Windsor, Ontario (Canada)

1997-06-01

289

Influence of reservoir heterogeneity on gas resource potential for geologically based infill drilling, Brooks and I-92 reservoirs, Frio Formation, south Texas  

Microsoft Academic Search

Gas resource potential for strategic infill drilling or recompletion in a reservoir can be calculated by subtracting gas volumes derived using the material balance (pressure decline) method from volumes derived using a volumetric method. This resource potential represents remaining gas that is not in communication with existing wells. Frio reservoirs in mature, nonassociated gas plays located downdip from the Vicksburg

M. L. W. Jackson; W. A. Ambrose

1989-01-01

290

Influence of reservoir heterogeneity on gas resource potential for geologically based infill drilling, Brooks and I-92 reservoirs, Frio Formation, south Texas  

SciTech Connect

Gas resource potential for strategic infill drilling or recompletion in a reservoir can be calculated by subtracting gas volumes derived using the material balance (pressure decline) method from volumes derived using a volumetric method. This resource potential represents remaining gas that is not in communication with existing wells. Frio reservoirs in mature, nonassociated gas plays located downdip from the Vicksburg fault zone are characterized by multiple, vertically stacked sandstones. The Brooks reservoir, in La Gloria field, lies in a fluvial-dominated system that contains dip-elongate channel sandstone belts 1-2 mi wide. Within these belts are six or more vertically stacked channel-fill, point-bar and splay deposits. Depositional environments were interpreted from SP logs. Individual sandstones are separated vertically by thin mudstone layers and pinch out laterally into flood-plain deposits.

Jackson, M.L.W.; Ambrose, W.A. (Bureau of Economic Geology, Austin, TX (USA))

1989-09-01

291

Source rock heterogeneity of the Upper Jurassic Draupne Formation, North Viking Graben, and its relevance to petroleum generation studies  

Microsoft Academic Search

The Upper Jurassic Draupne Formation in the North Viking Graben, North Sea, has been studied to identify lateral and vertical variations in source rock characteristics and their effect on the timing of petroleum generation. Fourteen source rock samples from the western flank of the graben and five from the eastern flank were analysed using Rock-Eval analysis, microscopy, open system pyrolysis

Matthias Keym; Volker Dieckmann; Brian Horsfield; Michael Erdmann; Roberto Galimberti; Lung-Chuan Kua; Leslie Leith; Olaf Podlaha

2006-01-01

292

Method for determining the presence of hydrocarbons in subsurface geological formations by comparative assessment of compressional and shear wave reflection data  

SciTech Connect

This paper describes a method for determining the presence of hydrocarbons in subsurface geological formations by comparative assessment of acquired compressional wave reflection information and pseudoshear wave reflection information estimated from acquired compressional wave reflection information. It comprises the steps of: generating descending acoustic compressional waves from a plurality of acoustic wave sources and receiving and recording at a plurality of receivers ascending compressional wave reflection information produced at a subsurface interface; gathering the recorded compressional wave reflection information into sets of different source-receiver offsets having a common reflection boundary; correcting gathered compressional wave reflection information for normal moveout; measuring amplitudes of gathered compressional wave reflection information at given points in time for different source-receiver offset value; determining directly from the measured amplitude offset values pseudoshear wave reflection information, selecting compressional wave reflection information; selecting produced pseudoshear wave reflection information; combining selected compressional wave reflection information and selected pseudoshear wave reflection information according to the relation R/sub s/-R/sub s/, where R/sub p/ is the selected compressional wave reflection information and Rs is the selected pseudoshear wave reflection information; and comparing the combined wave reflection information to the selected compressional wave reflection information.

Goins, N.R.

1989-08-15

293

The formation and behavior of {open_quotes}vapor lock{close_quotes} pressure seals and associated hydrocarbon accumulations in geologically young basins  

SciTech Connect

This paper demonstrates a mechanism for the formation of geopressure and hydrocarbon accumulations in geologically young basins (e,g., Gulf of Mexico). Gas exsolving from solution in response to changes in temperature create a relative permeability barrier that restricts vertical fluid flow locally. Continued gas dissolution in source rock, transport and subsequent exsolution at shallower depths maintain the {open_quotes}vapor lock{close_quotes} seal. Any sands that are found within the pressure seal fill preferentially with the nonwetting gas and oil. Further migration of the trapped hydrocarbons is restricted by the capillary entry pressures of the surrounding shales; thus, capillary entry effects enhance the sealing nature of the pressure barrier. Numerical simulations demonstrate the viability of this model for the formation of geopressured reservoirs in young basins, and show that two distinct pressure seals can form under certain conditions. The model incorporates salient features from the Gulf of Mexico, including spatially-variable heat flux, methane and CO{sub 2} generation and transport, and a low-permeability shale as the continuous rock fabric. Steady state isotherms exhibit significant relief due to the variable heat flux, and gas exsolves from solution along two distinct isotherms. The gas forms a relative permeability barrier that restricts vertical fluid flow. As the gas saturation exceeds a critical saturation, any sands found within the pressure seals fill with the non-wetting hydrocarbons. Gas is trapped within the sands by capillary entry pressures of the surrounding shales, improving the sealing nature of the pressure barrier. Sensitivity studies show that specific seat geometry is sensitive to the variability in heat flow, gas content of the aqueous phase, and relative permeability and capillary pressure characteristics of both the sand and shale; however, one or more vapor lock seals form under a variety of conditions.

Benzing, W.M.; Shook, G.M. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1996-09-01

294

Uptake of isoprene by thin sulfuric acid films: Acid catalyzed heterogeneous uptake and the formation of monoterpenes and cyclic sesquiterpenes  

NASA Astrophysics Data System (ADS)

A high vacuum Knudsen flow reactor was used to determine the uptake coefficient, gamma, of isoprene on sulfuric acid films as a function of sulfuric acid weight percent, temperature, and relative humidity. No discernible dependence was observed for gamma over the range of temperatures (220 - 265 K) and pressures (10-6 Torr - 10-4 Torr) studied. However, the uptake coefficient increased with increased sulfuric acid concentration between the range of 70 wt% (gamma initial ~ 10-4) and 90 wt% (gamma initial ~ 10- 3). To determine reaction products, a bulk study was performed. Isoprene uptake was performed at higher pressures on 1 - 2 mL 85 wt % sulfuric acid and condensed phase products were extracted and analyzed using gas chromatography/mass spectrometry (GC/MS). Isoprene was observed to polymerize in the sulfuric acid and form monoterpenes and cyclic sesquiterpenes. Finally, addition of water to the 85% sulfuric acid/isoprene product mixture released these terpenes from the condensed phase into the gas phase. Atmospheric implications for heterogeneous acid catalyzed production of mono- and sequitepenes from isoprene will be discussed.

Connelly, B. M.; Tolbert, M.

2008-12-01

295

Kinetic Monte Carlo simulation of surface heterogeneity in graphite anodes for lithium-ion batteries: Passive layer formation  

Microsoft Academic Search

The properties and chemical composition of the solid-electrolyte-interface (SEI) layer have been a subject of intense research due to their importance in the safety, capacity fade, and cycle life of Li-ion secondary batteries. Kinetic Monte Carlo (KMC) simulation is applied to explore the formation of the passive SEI layer in the tangential direction of the lithium- ion intercalation in a

Ravi N. Methekar; Paul W. C. Northrop; Kejia Chen; Richard D. Braatz; Venkat R. Subramanian

2011-01-01

296

Reservoir heterogeneity and hydrocarbon production in mixed dolomitic-clastic sequence: Escandalosa Formation, Barinas-Apure basin, southwestern Venezuela  

Microsoft Academic Search

Widespread dedolomitization and differential leaching occur in the Turonian O Member of the Escandalosa Formation, Barinas-Apure basin. Within this dolostone-dominated succession, calcite was developed through a dedolomitization process occurring in deeply buried dolomitized lime sediments previously deposited on a carbonate platform as well as dedolomitization on the associated glauconitic-quartzose sandstones of small-scale channels that scoured the platform. The dolomitized intervals

N. Escalona; J. Abud

1989-01-01

297

Heterogeneous nucleation-controlled particulate formation of recombinant human platelet-activating factor acetylhydrolase in pharmaceutical formulation.  

PubMed

Clinical lots of recombinant human platelet-activating factor acetylhydrolase (rhPAF-AH) were prepared in a lyophilized formulation. After reconstitution with sterile water for injection to form an aqueous solution (10 mM sodium citrate, 7.5 w/v% sucrose, and 0.1 w/v% Pluronic-F68, pH 6.5), a few visible, slowly growing particles formed consistently within hours at room temperature. To investigate the mechanism of this phenomenon, immediately after reconstitution, all protein aggregates and exogenous particles were removed by filtration. During 20 days incubation at room temperature, no visible aggregates formed in these filtered samples. In contrast, when nano-sized hydrophilic silica particles were added, they seeded rapid and extensive aggregation of rhPAF-AH. This effect was exacerbated in solutions containing a lower Pluronic-F68 concentration at 0.01%. Aggregation occurred even under conditions where rhPAF-AH adsorption was reversible, and induced no detectable changes to protein secondary and tertiary structures. Decreasing the extent (e.g., adding Pluronic-F68) or affinity (e.g., increasing solution pH) of rhPAF-AH adsorption on nano-sized silica particles was found to be effective at reducing aggregation. Accelerated aggregation was not observed when rhPAF-AH formulation was seeded with aggregated rhPAF-AH. These results show that rhPAF-AH aggregation proceeds through a heterogeneous nucleation-controlled mechanism, where exogenous particles present in solution serve as seeds on which rhPAF-AH adsorb, nucleate, and grow into large aggregates. PMID:15570600

Chi, Eva Y; Weickmann, Joachim; Carpenter, John F; Manning, Mark C; Randolph, Theodore W

2005-02-01

298

Numerical studies of radionuclide migration in heterogeneous porous media  

SciTech Connect

Burial of hazardous nuclear waste in geological repositories is considered to be in the best environmental interest. However, to minimize potential risk for future generations, an accurate knowledge is required of the time- and space-dependent concentrations of the radionuclides as they migrate from their burial site. Numerical solutions to both the conventional advection-dispersion equation and a new transport equation (containing directional dependence) are utilized to study the migration of radionuclides in heterogeneous media. In particular, layered fractured formations are examined. The new transport formulation, with its directional dependence, yields details in concentration profiles not shown by the advection-dispersion approach.

Buckley, R.L.; Loyalka, S.K. (Univ. of Missouri, Columbia, MO (United States)); Williams, M.M.R. (Electrowatt Engineering Services Ltd., Sussex (United Kingdom))

1994-11-01

299

Geology Fieldnotes: Oregon Caves National Monument  

NSDL National Science Digital Library

Oregon Caves National Monument is an active marble cave created by natural forces over hundreds of thousands of years in one of the world's most diverse geologic realms. Features of the site include park geology information, maps, photographs, related links, and visitor information. The park geology section discusses the cave's development and geologic history, its formations, and its development as a National Monument. The maps section includes an area map of the National Monument.

300

Pennsylvania Geology  

NSDL National Science Digital Library

Three decades after it was published, the Second Geological Survey of Pennsylvania was described as "the most remarkable series of reports ever issued by any survey." Considering the diversity of other geological reports, this was no small compliment. Drawing on support from the Marion and Kenneth Pollock Libraries Program Fund, the Pennsylvania State University Libraries' Digital Preservation Unit was able to digitize not only this fabled Survey, but also the Third and Fourth Surveys as well. Visitors can use the search engine on the homepage to look for items of interest, or they can just browse through the collection at their leisure. The surveys include various maps and illustrations that track mineral deposits and the disposition and location of other natural resources. Additionally, users can look through a miscellaneous set of publications from the early 20th century related to survey work performed by the U.S. Geological Survey.

301

Teaching Geology  

NSDL National Science Digital Library

This rather remarkable website contains a great collection of resources for web-based instruction and demonstrations of geology concepts. The collection includes, under Classroom demonstration, the very useful SeisMac 3.0, which is an application for Mac OS X that turns a laptop computer into a " low-resolution strong-motion accelerometer," or a basic seismograph. It works by accessing the computer's Sudden Motion Sensor in order to display real-time, three axis accelerations graphs. Visitors can use the application to watch the seismic waves go up and down just by tapping their feet on the floor nearby. Other resources include Virtual Earth (an "interactive minicourse on thermal convection") and a link to Geology in the news, which collates important news stories with a geological theme.

302

The relationship of dynamical heterogeneity to the Adam-Gibbs and random first-order transition theories of glass formation.  

PubMed

We carefully examine common measures of dynamical heterogeneity for a model polymer melt and test how these scales compare with those hypothesized by the Adam and Gibbs (AG) and random first-order transition (RFOT) theories of relaxation in glass-forming liquids. To this end, we first analyze clusters of highly mobile particles, the string-like collective motion of these mobile particles, and clusters of relative low mobility. We show that the time scale of the high-mobility clusters and strings is associated with a diffusive time scale, while the low-mobility particles' time scale relates to a structural relaxation time. The difference of the characteristic times for the high- and low-mobility particles naturally explains the well-known decoupling of diffusion and structural relaxation time scales. Despite the inherent difference of dynamics between high- and low-mobility particles, we find a high degree of similarity in the geometrical structure of these particle clusters. In particular, we show that the fractal dimensions of these clusters are consistent with those of swollen branched polymers or branched polymers with screened excluded-volume interactions, corresponding to lattice animals and percolation clusters, respectively. In contrast, the fractal dimension of the strings crosses over from that of self-avoiding walks for small strings, to simple random walks for longer, more strongly interacting, strings, corresponding to flexible polymers with screened excluded-volume interactions. We examine the appropriateness of identifying the size scales of either mobile particle clusters or strings with the size of cooperatively rearranging regions (CRR) in the AG and RFOT theories. We find that the string size appears to be the most consistent measure of CRR for both the AG and RFOT models. Identifying strings or clusters with the "mosaic" length of the RFOT model relaxes the conventional assumption that the "entropic droplets" are compact. We also confirm the validity of the entropy formulation of the AG theory, constraining the exponent values of the RFOT theory. This constraint, together with the analysis of size scales, enables us to estimate the characteristic exponents of RFOT. PMID:23556792

Starr, Francis W; Douglas, Jack F; Sastry, Srikanth

2013-03-28

303

Ambient measurements of chemical and physical properties of organic aerosols: Insights into formation, growth, and heterogeneous chemistry  

NASA Astrophysics Data System (ADS)

Organic aerosols are a ubiquitous component of the troposphere, from heavily polluted cities to the remote Arctic. In Chapters II, III, and V of this dissertation, the formation of organic aerosol through observations of ambient size distributions is addressed. Chapter IV presents a new pathway for the formation of nitrous acid (HONO) in the urban atmosphere. In Chapter II, the size-resolved chemical composition of sub-micron aerosol was measured at a suburban forested site in North Carolina. Two events were identified in which particle growth, presumably by gas-to-particle conversion, was dominated by accumulation of organic aerosol mass. Growth rates between 1.2 nm hr-1 and 4.9 nm hr-1 were observed. Using a mass-spectral deconvolution method coupled with linear regression analysis, the sub-micron organic aerosol mass observed during the campaign, and during events, was determined to have been influenced by both local and regional secondary processes with only a minor influence from combustion sources. In Chapter III, the chemical characteristics of sub-10-micron aerosol were explored as a function of ambient particle size at a coastal and inland site in New England. Average organic carbon (OC) concentrations of 4.9 microg C m-3 and 3.4 microg C m-3 were observed at the coastal site at the Isles of Shoals (IOS) and at the slightly inland site at Thompson Farm (TF), respectively. An average of 84 and 72% of OC was found to be water-soluble at IOS and TF, respectively. Size distributions indicate that the formation of dicarboxylic acids, especially oxalic acid, is driven by aqueous-phase reactions. A chemical fingerprint analysis suggests that all water-soluble OC at IOS resembles secondary organic aerosol (SOA), while WSOC at TF appears to result from mixed sources. In Chapter IV, a newly identified formation pathway for nitrous acid (HONO) is presented. HONO is an important precursor to hydroxyl radicals in the troposphere and thus contributes to the oxidative capacity of the atmosphere. The proposed pathway is shown to depend on the surface chemical characteristics of primary organic aerosol, and concentrations of HONO are shown to exceed those that can be explained by previously identified formation pathways. In Chapter V, particle growth events were observed at Summit, Greenland, an extremely remote Arctic site. Particle growth was linked indirectly to condensation of organic compounds because measured concentrations of sulfuric acid could not explain the observed growth rates of up to 0.963 nm hr -1. The snowpack may be the source of condensable organic precursors, and thus organic aerosol, based on prior observations at the site. This pathway represents a source of global SOA currently not taken into account that may have implications for climate regulation.

Ziemba, Luke D.

304

Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity  

SciTech Connect

The objectives of this project are to augment the National Reservoir Database (TORIS database) and to increase our understanding of geologic heterogeneities that affect the recoveries of oil and gas from carbonate reservoirs in the State of Alabama and to identify those resources that are producible at moderate cost. These objectives will be achieved through detailed geological, engineering, and geostatistical characterization of typical Jurassic Smackover Formation hydrocarbon reservoirs in selected productive fields in the State of Alabama. The results of these studies will be used to develop and test mathematical models for prediction of the effects of reservoir heterogeneities in hydrocarbon production. Work to date has focused on the completion of Subtasks 1, 2, and 3. Subtask 1 included the survey and tabulation of available reservoir engineering and geological data relevant to the Smackover reservoir in southwestern Alabama. Subtask 2 comprises the geological and engineering characterization of Smackover reservoir lithofacies. This has been accomplished through detailed examination and analysis of geophysical well logs, core material, well cuttings, and well-test data from wells penetrating Smackover reservoirs in southwestern Alabama. From these data, reservoir heterogeneities, such as lateral and vertical changes in lithology, porosity, permeability, and diagenetic overprint, have been recognized and used to produce maps, cross sections, graphs, and other graphic representations to aid in interpretation of the geologic parameters that affect these reservoirs. Subtask 3 includes the geologic modeling of reservoir heterogeneities for Smackover reservoirs. This research has been based primarily on the evaluation of key geologic and engineering data from selected Smackover fields. 1 fig.

Mancini, E.A.

1990-01-01

305

Geologic Explorations  

NSDL National Science Digital Library

One of the latest offerings from the North Carolina State University's Web site Science Junction (last mentioned in the November 25, 1998 Scout Report) is the Geologic Explorations page. By clicking on the respective coordinates of each location, users can explore twelve areas in the western United States with 360-degree panoramic QuickTime movies and digital photography. Set up as a type of lesson for students, the main page suggests paying close attention to the unique geologic features and gives a few questions to answer about each area. The site is very easy to use and provides some breathtaking vistas of some of the most beautiful areas of the US.

Bodzin, Alec M.

2001-01-01

306

Radon-222 as a Tracer of Water-Air Dynamics in the Unsaturated Zone of Geological Carbonate Formation: Example of an Underground Quarry (Oligocene Aquitain Limestone, France)  

NASA Astrophysics Data System (ADS)

Complex process in the unsaturated zone affect the transfers of fluids. Within the context of an integrated study on the process of the meteoric diagenesis in a carbonate formation, we try to determine the time transit of fluids. The aim of this study is to see whether radon 222 is a good natural tracer of fluids vertical diffusivity. Radon is an inert radioactive gas. It has three isotopes 222Rn, 220Rn, 219Rn. 222Rn comes from the decay of 238U. The 222Rn half-life (3.82 days) allows it to be transported far from its origin (Fleischer et al., 1981). Temporal variations of radon activity in soil gas depend on several factors such as meteorological variables (temperature, rainfall, atmospheric pressure, etc) and geological variables (concentration of radium in the soil, porosity, grain size, tectonic activity, etc.) (Abbad et al., 1993). The radon was measured on an experimental site : soil (0.40 meter thick) is lying on the Oligocene limestone (15 meters thick). This limestone was exploited in underground quarry with several levels (7 meters and 10 meters deep). Radon product comes from soil clays and limons for the major part and quaternary loess trapped in the limestone karstic framework for an other part. In the unsaturated zone, radon moves vertically in the gaseous phase under piston effect of the liquid phase. It moves as well dissolve in the liquid phase. The underground quarry atmosphere of the two levels shows variations of radon concentration in the time. The results show correlation between the maxima of effective precipitations and the maxima ones of radon concentration in the underground quarry atmosphere with a seven months dephasing. Dephasing between the maxima of effective precipitations and the maxima of moisture in the porous rock is only five months. This correlation leads to a diffusion model of radon in the unsaturated zone.

Loisy, C.; Franceschi, M.; Cerepi, A.

2006-12-01

307

Architecture, internal heterogeneity, and resulting drainage efficiency of Upper Oligocene Frio Formation inner-shelf sandstone reservoirs in West Fulton Beach Field, Aransas County, Texas  

SciTech Connect

The architecture, internal heterogeneity, and production history of selected reservoirs in West Fulton Beach field, Copano Bay, Aransas County, Texas, were examined as part of a project to identify additional oil and gas reserves on Texas state lands. Upper Oligocene Frio Formation reservoirs in this field have yielded more than 146 bcf of gas and 8 MMbbl of oil. A high-resolution genetic stratigraphic analysis of inner-shelf sandstone reservoirs used well log and petrophysical data to locate uncontacted or incompletely drained reservoir compartments. Shelf sandstone reservoirs are composed of thin (2-6 ft) sandstones that are laterally isolated but commonly vertically stacked and amalgamated into units as much as 16 ft thick. Individual sandstones constitute separate reservoir compartments that are vertically isolated if surrounded by inner-shelf shales or are in partial communication if vertically stacked, separated by a low-permeability bioturbated sandstone or siltstone layer of varying thickness. Heterogeneity within individual sandstone units is low. Deposition of inner-shelf sandstones varies - from proximal settings, below fair-weather wave base but above storm wave base, where the sandstones are thicker, more commonly amalgamated, and form well-interconnected compartments - to distal settings below storm wave base, where they are thinner and more commonly isolated. Production histories indicate that completions in proximal settings can drain more than 600 ac in a gas reservoir, whereas those in distal settings drain less than 200 ac. High-resolution stratigraphic analysis of inner-shelf sand-stone reservoirs at West Fulton Beach field has identified 11 bcf of additional reserves in untapped and incompletely drained reservoir compartments. The 63 other major fields of the downdip Frio barrier-bar/strandplain play of the central Texas Gulf Coast may contain as much as 500 bcf of additional gas that could be identified through similar efforts.

Knox, P.R. [Univ. of Texas, Austin, TX (United States)

1994-09-01

308

Geologic Time  

NSDL National Science Digital Library

This site contains 24 questions on the topic of geologic time, which covers dating techniques and unconformities. This is part of the Principles of Earth Science course at the University of South Dakota. Users submit their answers and are provided immediate feedback.

Heaton, Timothy

309

Physical geology  

Microsoft Academic Search

The book integrates current thinking on processes (plate techtonics, chemical cycles, changes throughout geologic time). It is an introduction to investigations into the way the earth works, how mountains are formed, how the atmosphere, hydrosphere, crust and mantle interact with each other. Treatments on climate, paleoclimatology and landscape evolution are included, as is a discussion on how human activity affects

B. Skinner; S. Porter

1987-01-01

310

Geologic Time.  

ERIC Educational Resources Information Center

|Discusses the historical development of the concept of geologic time. Develops the topic by using the major discoveries of geologists, beginning with Steno and following through to the discovery and use of radiometric dating. An extensive reference list is provided. (JM)|

Albritton, Claude C., Jr.

1984-01-01

311

Geologic controls influencing CO2 loss from a leaking well.  

SciTech Connect

Injection of CO2 into formations containing brine is proposed as a long-term sequestration solution. A significant obstacle to sequestration performance is the presence of existing wells providing a transport pathway out of the sequestration formation. To understand how heterogeneity impacts the leakage rate, we employ two dimensional models of the CO2 injection process into a sandstone aquifer with shale inclusions to examine the parameters controlling release through an existing well. This scenario is modeled as a constant-rate injection of super-critical CO2 into the existing formation where buoyancy effects, relative permeabilities, and capillary pressures are employed. Three geologic controls are considered: stratigraphic dip angle, shale inclusion size and shale fraction. In this study, we examine the impact of heterogeneity on the amount and timing of CO2 released through a leaky well. Sensitivity analysis is performed to classify how various geologic controls influence CO2 loss. A 'Design of Experiments' approach is used to identify the most important parameters and combinations of parameters to control CO2 migration while making efficient use of a limited number of computations. Results are used to construct a low-dimensional description of the transport scenario. The goal of this exploration is to develop a small set of parametric descriptors that can be generalized to similar scenarios. Results of this work will allow for estimation of the amount of CO2 that will be lost for a given scenario prior to commencing injection. Additionally, two-dimensional and three-dimensional simulations are compared to quantify the influence that surrounding geologic media has on the CO2 leakage rate.

Hopkins, Polly L.; Martinez, Mario J.; McKenna, Sean Andrew; Klise, Katherine A.

2010-12-01

312

Overview of IPSN research on the evolution of the natural systems in support of the French methodology for the safety evaluation of radwaste disposal in deep geological formations.  

National Technical Information Service (NTIS)

A regulatory guidance has been recently set up in France for the safety assessment of radwaste deep geological disposal: the present paper concerns the requirements related to bedrock stability issues and their technical background. This regulation relies...

P. Escalier des Orres T. Granier B. Mohammadioun

1992-01-01

313

Geological Steering of Horizontal Wells  

Microsoft Academic Search

Horizontal well technology has evolved rapidly. The most difficult concerns have changed from borehole stability and drilling techniques to completion, stimulation, and formation evaluation. Tomorrow's challenge lies in steering the well path precisely by use of formation geologic and geophysical information. This geosteering technique is credited with major improvements in drilling results. One definition of geosteering is the planned interactive

D. Meehan

1994-01-01

314

Heterogeneity of cell death.  

PubMed

Cell death constitutes a number of heterogeneous processes. Despite the dynamic nature of cell death, studies of cell death have primarily focused on apoptosis, and cell death has often been viewed as static events occurring in linear pathways. In this article we review cell death heterogeneity with specific focus on 4 aspects of cell death: the type of cell death; how it is induced; its mechanism(s); the results of cell death, and the implications of cell death heterogeneity for both basic and clinical research. This specifically reveals that cell death occurs in multiple overlapping forms that simultaneously occur within a population. Network and pathway heterogeneity in cell death is also discussed. Failure to integrate cell death heterogeneity within analyses can lead to inaccurate predictions of the amount of cell death that takes place in a tumor. Similarly, many molecular methods employed in cell death studies homogenize a population removing heterogeneity between individual cells and can be deceiving. Finally, and most importantly, cell death heterogeneity is linked to the formation of new genome systems through induction of aneuploidy and genome chaos (rapid genome reorganization). PMID:23548436

Stevens, J B; Abdallah, B Y; Liu, G; Horne, S D; Bremer, S W; Ye, K J; Huang, J Y; Kurkinen, M; Ye, C J; Heng, H H Q

2013-04-03

315

Chapter 7. The GIS project for the geologic assessment of undiscovered oil and gas in the Cotton Valley group and Travis Peak and Hosston formations, East Texas basin and Louisiana-Mississippi salt basins provinces.  

USGS Publications Warehouse

A geographic information system (GIS) focusing on the Upper Jurassic-Lower Cretaceous Cotton Valley Group and the Lower Cretaceous Travis Peak and Hosston Formations in the northern Gulf Coast region was developed as a visual-analysis tool for the U.S. Geological Survey's 2002 assessment of undiscovered, technically recoverable oil and natural gas resources in the East Texas Basin and Louisiana-Mississippi Salt Basins Provinces. The Central Energy Resources Team of the U.S. Geological Survey has also developed an Internet Map Service to deliver the GIS data to the public. This mapping tool utilizes information from a database about the oil and natural gas endowment of the United States-including physical locations of geologic and geographic data-and converts the data into visual layers. Portrayal and analysis of geologic features on an interactive map provide an excellent tool for understanding domestic oil and gas resources for strategic planning, formulating economic and energy policies, evaluating lands under the purview of the Federal Government, and developing sound environmental policies. Assessment results can be viewed and analyzed or downloaded from the internet web site, http://energy.cr.usgs.gov/oilgas/noga/ .

Biewick, Laura R. H.

2006-01-01

316

Geologic nozzles  

Microsoft Academic Search

Sonic velocities of geologic fluids, such as volcanic magmas and geothermal fluids, can be as low as 1 m\\/s. Critical velocities in large rivers can be of the order of 1-10 m\\/s. Because velocities of fluids moving in these settings can exceed these characteristic velocities, sonic and supersonic gas flow and critical and supercritical shallow-water flow can occur. The importance

Susan Werner Kieffer

1989-01-01

317

Physical Geology  

NSDL National Science Digital Library

This Tulane University course covers the nature of the Earth, the development of its surficial features, and the results of the interaction of chemical, physical, and biological factors on the planet. Lecture notes are about energy and minerals; igneous, metamorphic and sedimentary rocks; weathering and soils; geologic time; mass wasting; streams; groundwater; wind action and deserts; oceans; deformation of rock; earthquakes and the interior of the Earth; global tectonics; planetary changes; and glaciers.

Nelson, Stephen

318

Numerical simulation of CO2 storage at Ketzin: The impact of heterogeneity on the distribution of CO2  

Microsoft Academic Search

In order to increase the understanding of geological CO2 storage, data obtained from on-site monitoring at the Ketzin injection site (CO2SINK) are being used to verify the results of numerical models. As with all reservoirs, the uncertainties inherent in the Ketzin formation prevent the resolution of a deterministic state. These uncertainties are caused by heterogeneities within the reservoir and, along

U. Lengler; M. Kühn

2009-01-01

319

SEISMIC DETERMINATION OF RESERVOIR HETEROGENEITY: APPLICATION TO THE CHARACTERIZATION OF HEAVY OIL RESERVOIRS  

SciTech Connect

The objective of the project was to examine how seismic and geologic data can be used to improve characterization of small-scale heterogeneity and their parameterization in reservoir models. The study focused on West Coalinga Field in California. The project initially attempted to build reservoir models based on different geologic and geophysical data independently using different tools, then to compare the results, and ultimately to integrate them all. We learned, however, that this strategy was impractical. The different data and tools need to be integrated from the beginning because they are all interrelated. This report describes a new approach to geostatistical modeling and presents an integration of geology and geophysics to explain the formation of the complex Coalinga reservoir.

Matthias G. Imhof; James W. Castle

2005-02-01

320

Geological steering of horizontal wells  

SciTech Connect

Horizontal well technology has evolved rapidly. The most difficult concerns have changed from borehole stability and drilling techniques to completion, stimulation, and formation evaluation. Tomorrow's challenge lies in steering the well path precisely by use of formation geologic and geophysical information. This geosteering technique is credited with major improvements in drilling results. One definition of geosteering is the planned interactive navigation of a wellbore using geological criteria. Geosteering implies feedback, with all available data continuously entered into the model of the well path and reservoir. Potential gains in production must be balanced with additional drilling and formation evaluation costs. Proper characterization requires knowledge of where the well path is located, where the current trajectory will take the well path, and where the wellbore should go. Uncertainty in geological modeling and the need to maximize profitability require an interdisciplinary team approach.

Meehan, D.N. (Union Pacific Resources Co., Fort Worth, TX (United States))

1994-10-01

321

Tour of Park Geology: Shoreline Geology  

NSDL National Science Digital Library

This National Park Service (NPS) site provides links to shoreline geology fieldnotes for National Parks, Monuments, and Recreation Areas. When appropriate, fieldnotes include visitor information, geology, maps, photographs, multimedia resources, geologic research, and teacher features (lessons for teaching geology with National Park examples). Some of the parks included on this site: Acadia National Park, Everglades National Park, and Padre Island National Seashore.

322

Elements of petroleum geology  

SciTech Connect

This work surveys the modern science of petroleum geology. Its aim is twofold: to describe generation, migration, and entrapment of oil and gas, and to outline the various procedures used in their location, evaluation, and production. Selley begins the book with an account of the physical and chemical properties of petroleum, followed by a review of the methods of petroleum exploration and production, including drilling, geophysical exploration techniques, wireline logging, and subsurface geological mapping. Selley next describes the temperatures and pressures of the subsurface environment and the composition and hydrodynamics of connate fluids. He goes on to examine the generation and migration of petroleum, reservoir rocks, and trapping mechanisms, the habitat of petroleum in sedimentary basins, and the composition and formation of tar sands and oil shales. Selley ends the book with a brief review of prospect risk analysis, reserve estimation, and other economic topics.

Selley, R.C.

1985-01-01

323

Upper Cenozoic Geologic Map, Yellowstone Plateau Volcanic Field  

NSDL National Science Digital Library

This geologic map shows Tertiary and Quaternary rock formations, volcanic and surficial deposits, faults, contacts, and other geologic features in Yellowstone National Park. The map is freely downloadable as a PDF file.

Robert, Christiansen; Survey, U. S.

324

Geological map of the future: digital, interactive, and 3D  

NASA Astrophysics Data System (ADS)

Geological survey agencies are developing methods for government geological mapping in the post-paper map era. Surficial and bedrock maps are being digitized and reconciled, while multiple generations of legends are being made accessible in a categorized format. Regional 3D geological models that integrate soils and geology, surficial and bedrock geology, as well as onshore and offshore are increasingly in demand as the information, technology, and protocols to build them progress. Applications such as regional groundwater modelling require digitizing, reconciliation, and assembly of a digital elevation model, bathymetry, offshore geology, soils, surficial geology, public domain drillhole and geophysical data, bedrock maps, and existing stratigraphic models typically expressed as structure contours. New stratigraphic modelling, particularly required for surficial unconsolidated deposits in many regions, requires information from cored holes logged by geologists as well as geophysical surveys. These high-quality results are extrapolated laterally using drill hole data, commonly large quantities of water well data of varying resolution and reliability. Much effort is required to adequately georeference the drillhole data, and to parse large numbers of unique lithological descriptions. Stratigraphic modelling methods ideally use all data and an approach that permits judgement in the acceptance or rejection of data, while interpolation and extrapolation are guided by genetic insights. Models are best captured as a grid of predicted stratigraphy profiles that convey expert opinion on interpolation and extrapolation from the data points. Reconciliation of mapping with that of neighbouring jurisdictions is a key step, as is balancing subjective definition of strata with more objective geostatistical approaches to characterizing the heterogeneous physical properties of the strata. Progress is readily achievable in undeformed strata, while deformed strata present far greater challenges. Increasingly, databases of observations and measurements are being retained alongside the interpreted model, and models are being assigned varying confidence levels such that the result is seen not as an end but a means for prioritizing new mapping. Current activity is broadening our reliance not only from paper maps to digital models, but also from plan view maps, to drillhole databases, to 3D models, to dynamic models such as groundwater flow models. Pressing user requirements demand that geological survey work rapidly advance along this progression.

Thorleifson, H.

2003-12-01

325

Geology Fieldnotes: Capitol Reef National Park, Utah  

NSDL National Science Digital Library

This Capitol Reef National Park site contains park geology information, park maps, photographs, visitor information, and a teacher feature (resources for teaching geology with National Park examples). Geologic data includes descriptions of the Waterpocket Fold, a monocline formed in the Laramide Orogeny and made of sedimentary rock. Also covered is erosion, and details about the Cathedral Valley outcrop of gypsum. This formation is Permian to Cretaceous in age (270-80 million years old).

326

In situ formation of HRh(CO) 2(PPh 3) 2 active species on the surface of a SBA15 supported heterogeneous catalyst and the effect of support pore size on the hydroformylation of propene  

Microsoft Academic Search

A method of in situ formation of HRh(CO)2(PPh3)2 active species on the surface of heterogeneous Rh\\/SBA-15 catalyst has been developed and confirmed in this work. The amount of active species formed inside the pores can be controlled by the support pore size. This class of PPh3-Rh\\/SBA-15 catalyst has been employed in propene hydroformylation to be highly active, selective, stable, easily

Li Yan; Yun J. Ding; Li W. Lin; He J. Zhu; Hong M. Yin; Xian M. Li; Yuan Lu

2009-01-01

327

Co2 geological sequestration  

SciTech Connect

Human activities are increasingly altering the Earth's climate. A particular concern is that atmospheric concentrations of carbon dioxide (CO{sub 2}) may be rising fast because of increased industrialization. CO{sub 2} is a so-called ''greenhouse gas'' that traps infrared radiation and may contribute to global warming. Scientists project that greenhouse gases such as CO{sub 2} will make the arctic warmer, which would melt glaciers and raise sea levels. Evidence suggests that climate change may already have begun to affect ecosystems and wildlife around the world. Some animal species are moving from one habitat to another to adapt to warmer temperatures. Future warming is likely to exceed the ability of many species to migrate or adjust. Human production of CO{sub 2} from fossil fuels (such as at coal-fired power plants) is not likely to slow down soon. It is urgent to find somewhere besides the atmosphere to put these increased levels of CO{sub 2}. Sequestration in the ocean and in soils and forests are possibilities, but another option, sequestration in geological formations, may also be an important solution. Such formations could include depleted oil and gas reservoirs, unmineable coal seams, and deep saline aquifers. In many cases, injection of CO2 into a geological formation can enhance the recovery of hydrocarbons, providing value-added byproducts that can offset the cost of CO{sub 2} capture and sequestration. Before CO{sub 2} gas can be sequestered from power plants and other point sources, it must be captured. CO{sub 2} is also routinely separated and captured as a by-product from industrial processes such as synthetic ammonia production, H{sub 2} production, and limestone calcination. Then CO{sub 2} must be compressed into liquid form and transported to the geological sequestration site. Many power plants and other large emitters of CO{sub 2} are located near geological formations that are amenable to CO{sub 2} sequestration.

Xu, Tianfu

2004-11-18

328

Impact of the heterogeneous hydrolysis of N2O5 on chemistry and nitrate aerosol formation in the lower troposphere under photosmog conditions  

Microsoft Academic Search

The impact of the heterogeneous hydrolysis of N2O5 on tropospheric gas phase and particle phase chemistry was investigated by performing model simulations with two comprehensive model systems and taking into account recent findings on the heterogeneous reaction probability of N2O5. Hereby, we focused on photosmog conditions in the lower troposphere. Chemistry box model runs were carried out neglecting transport and

N. Riemer; H. Vogel; B. Vogel; B. Schell; I. Ackermann; C. Kessler; H. Hass

2003-01-01

329

Geological Time Scale  

NSDL National Science Digital Library

This document describes how geologic time is approached in discussions of geologic topics. The uses of relative time and absolute time are compared, and a geologic time scale is provided to represent both concepts. References are provided.

330

Depositional facies control of reservoir heterogeneity and performance, Cretaceous sandstone reservoirs, south-central Alberta basin  

SciTech Connect

The profound influence of depositional factors on external geometry and internal heterogeneity of clastic reservoirs has not been fully appreciated in the field of development geology to date. Reservoir geometry is primarily a function of depositional environment, whereas reservoir heterogeneity will be controlled by both depositional and diagenetic factors. Depositionally controlled heterogeneities are usually manifested as porosity and directional permeability contrasts resulting from textural variations between facies. Therefore, thorough documentation of depositional facies variability and reservoir architecture is mandatory for understanding permeability heterogeneities and for implementing secondary recovery schemes in any given reservoir. Cretaceous reservoirs in the Alberta basin provide outstanding examples of depositional control on reservoir continuity and performance. The variable geometries of reservoir sandstone bodies in the Albian Viking Formation can be explained in terms of depositional framework related to an overall sequence stratigraphic model. This depositional framework also governs the complexity of internal facies-controlled heterogeneities related to directional textural contrasts. Similarly, hydrocarbon-bearing sandstone bodies in both the Aptian-Albian Manville Group and the Turonian Cardium Formation display highly fluctuating reservoir-performance trends that are related to degree of facies complexity caused by variations in depositional framework trends.

Reinson, G.E. (Geological Survey of Canada, Calgary, Alberta (Canada))

1991-03-01

331

Dynamic pore network model of surface heterogeneity in brine-filled porous media for carbon sequestration.  

PubMed

Trapping of carbon in deep underground brine-filled reservoirs is a promising approach for the reduction of atmospheric greenhouse gas emissions. However, estimation of the amount of carbon dioxide (CO(2)) that can be captured in a given reservoir and the long-term storage stability remain a challenge. One difficulty lies in the estimation of local capillary pressure effects that arise from mineral surface heterogeneity inherent in underground geological formations. As a preliminary step to address this issue, we have performed dynamic pore network modelling (PNM) simulations of two-phase immiscible flow in two-dimensional structured porous media with contact angle heterogeneity under typical reservoir conditions. We begin by characterizing the network with a single, uniform contact angle. We then present saturation patterns for networks with homogeneous and heterogeneous contact angles distributions, based on two common reservoir minerals: quartz and mica, both of which have been well-characterized experimentally for their brine-CO(2) contact angles. At lower flow rates, we found moderately higher saturations for the heterogeneous networks than for the homogeneous ones. To characterize the fingering patterns, we have introduced R as the ratio of filled throats to the total network saturation. Based on this measure, the heterogeneous networks demonstrated thicker fingering patterns than the homogeneous networks. The computed saturation patterns demonstrate the importance of considering surface heterogeneity in pore-scale modelling of deep saline aquifers. PMID:22585260

Ellis, Jonathan S; Bazylak, Aimy

2012-05-15

332

Separation and Capture of CO2 from Large Stationary Sources and Sequestration in Geological Formations: A Summary of the 2003 Critical Review  

SciTech Connect

Increasing amounts of carbon dioxide (CO2) in the atmosphere, and the resulting global warming effect, is a major air quality concern. CO2 is the most abundant greenhouse gas emitted by fossil-fuel combustion for power generation, transportation, and heating. Reducing worldwide emissions of CO2 will require many mitigation measures, including reductions in energy consumption, more efficient use of available energy, renewable energy sources, and carbon sequestration. The feasibility of capturing CO2 from large point sources and subsequent geological sequestration is the subject of this year’s Critical Review.

White, C.M.; Strazisar, B.R.; Granite, E.J.; Hoffman, J.S.; Pennline, H.W.

2003-06-01

333

Geology and Radiometry of West Macedonia (Greece).  

National Technical Information Service (NTIS)

Car borne scintillometry survey in W. Macedonia (Greece) showed that the granitic rocks of the area, the zone centered on the Tertiary volcanic rocks of Almopia zone and a large part of adjacent sediments constitute the most promising geological formation...

D. G. Minatidis

1984-01-01

334

Impact of the heterogeneous hydrolysis of N2O5 on chemistry and nitrate aerosol formation in the lower troposphere under photosmog conditions  

NASA Astrophysics Data System (ADS)

The impact of the heterogeneous hydrolysis of N2O5 on tropospheric gas phase and particle phase chemistry was investigated by performing model simulations with two comprehensive model systems and taking into account recent findings on the heterogeneous reaction probability of N2O5. Hereby, we focused on photosmog conditions in the lower troposphere. Chemistry box model runs were carried out neglecting transport and deposition processes. The heterogeneous hydrolysis of N2O5 leads to a decrease of ozone under low-NOx conditions and to a strong increase of ozone under high-NOx conditions. One-dimensional simulations were performed to take into account vertical mixing processes, deposition, and temporal changes of the emissions. The rate constant for the heterogeneous hydrolysis was determined depending on the simulated aerosol surface area density. A large impact of the heterogeneous hydrolysis on the nocturnal concentrations of N2O5, NO3, HNO3, and the surface area density and nitrate content of the aerosol is found. However, the effect of the hydrolysis of N2O5 on ozone decreases considerably compared to the box model simulations. Three-dimensional simulations for a typical summer smog situation for the southwestern part of Germany and on the European scale, which cover a variety of atmospheric and emission conditions, confirm these findings. The impact of heterogeneous hydrolysis on ozone is small, but it causes remarkable changes in the nocturnal concentrations of nitrogen-containing species and on aerosol properties such as surface area density and nitrate content.

Riemer, N.; Vogel, H.; Vogel, B.; Schell, B.; Ackermann, I.; Kessler, C.; Hass, H.

2003-02-01

335

Geology Fieldnotes: Grand Teton National Park, Wyoming  

NSDL National Science Digital Library

This National Park Service resource includes information about geology, park maps, visitor information, photographs, and links to other sites about this park. Geologic information spans the entire history of the park, beginning 2.5 billion years ago (Precambrian) to the present. Details about the different rock types and their formation, mountain building through plate tectonics and the Laramide Orogeny, formation of valleys and canyons, volcanism in the area, and erosion by glaciers are all covered.

336

Geologic mapping as a method for the construction of a detailed and testable lithostratigraphic model for the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona  

Microsoft Academic Search

The Upper Triassic Chinle Formation in Petrified Forest National Park represents some of the most intensively studied Upper Triassic strata in western North America. Five stratigraphic members are exposed within the park, from oldest to youngest: the Mesa Redondo, Blue Mesa, Sonsela, Petrified Forest, and Owl Rock Members. Despite numerous stratigraphic studies of the Chinle Formation and two attempts at

L. A. Skinner; J. W. Martz; W. Parker; J. Raucci; P. J. Umhoefer

2010-01-01

337

Geology Fieldnotes: Zion National Park, Utah  

NSDL National Science Digital Library

Zion is located on the edge of the Colorado Plateau, and is part of a formation known as the Grand Staircase (Bryce Canyon and the Grand Canyon are also part of this formation). The site discusses the formation of the park, from sedimentation 240 million years ago (Triassic), to lithification, uplift, and erosion. Visible formations include the Navajo sandstone and the Kaibab formation. Additional resources include visitor information, maps, photographs, and a teacher feature (lessons for teaching geology with National Parks as examples).

Foos, Annabelle

338

Research on 3D Geological Modeling by Using GOCAD Software  

Microsoft Academic Search

This paper presents technical issues on use and analysis of one kind of 3D geological modeling software named GOCAD. As the conventional geological information is not sufficient to meet the requirements of the current engineering construction, 3D geological modeling needs to be constructed. Otherwise, the key techniques are quite important to 3D modeling in engineering construction formation when using GOCAD.

Li Yongcheng; Shen Naiqi; Li Biao; Yan Yan; Dong Mei

2010-01-01

339

Unraveling Geological History: Glaciers and Faults at Discovery Park, Seattle  

NSDL National Science Digital Library

This introductory geology field exercise asks students to make individual observations about parts of an outcrop, then combine their observations in larger teams to interpret the overall geological history of the exposure. Content learning includes stratigraphy, faulting, and local geologic history; process learning includes data gathering and recording, hypothesis formation, and outlining helpful evidence that could be gathered in the future.

Tucker, Trileigh

340

History of Geology.  

ERIC Educational Resources Information Center

|Discusses: (1) geologists and the history of geology; (2) American historians and the history of geology; (3) history of geology in the 1980s; (4) sources for the history of geology (bibliographies, dictionaries, encyclopedias, handbooks, periodicals, public/official histories, compilations, and books); (5) research opportunities; and (6) other…

Greene, Mott T.

1985-01-01

341

Practical petroleum geology  

SciTech Connect

This book presents the scope and content of the field of petroleum geology from the standpoint of the practicing petroleum geologist. Includes chapters on basic geological concepts, the sedimentation process, accumulation of hydrocarbons, exploration, economic examination, drilling of exploratory wells, recovering oil and gas (reservoir geology), and the relationship of geology to the petroleum industry as a whole.

Not Available

1985-01-01

342

Formation and Structure of Lignin in Monocotyledons. III. Heterogeneity of Sugarcane (Saccharum officinarum L.) Lignin with Respect to the Composition of Structural Units in Different Morphological Regions  

Microsoft Academic Search

Heterogeneity of sugarcane lignin with respect to the composition of structural units in different morphological regions was studied by microautoradiography and some degradative analyses. Structure of the lignin differs among fiber, vessel and parenchyma. The lignin in the secondary wall of fiber is composed of syringyl (S)-, guaiacyl (G)- and p-hydroxyphenyl (H)-propane units with accompanying phenolic acid residues, and the

Lanfang He; Noritsugu Terashima

1990-01-01

343

Heterogeneous Gossip  

NASA Astrophysics Data System (ADS)

Gossip-based information dissemination protocols are considered easy to deploy, scalable and resilient to network dynamics. Load-balancing is inherent in these protocols as the dissemination work is evenly spread among all nodes. Yet, large-scale distributed systems are usually heterogeneous with respect to network capabilities such as bandwidth. In practice, a blind load-balancing strategy might significantly hamper the performance of the gossip dissemination.

Frey, Davide; Guerraoui, Rachid; Kermarrec, Anne-Marie; Koldehofe, Boris; Mogensen, Martin; Monod, Maxime; Quéma, Vivien

344

Heterogenized transition metal halides in the preparation of highly dispersed metal and metal complex catalysts. vi. the formation of the active surface of cupric chloride heterogenized on silica gel and its catalytic activity in the oxidation of cumene  

SciTech Connect

X-ray photoelectron and ESR spectroscopy was used to study the distribution and state of the active component on the support surface after the heterogenization of cupric chloride on lithium-modified silica gel. The chemisorption of CuC1/sub 2/ is mainly insular in nature. The catalytic activity of the catalysts obtained was studied in the liquid-phase oxidation of cumene to give cumyl hydroperoxide. The nature of the dependence of the specific catalytic activity on the surface concentration of the supported halide may be explained assuming insular nature for the chemisorption of CuC1/sub 2/. A comparison was carried out for the catalytic activity, selectivity and stability of the catalyst obtained with its impregnation analog and a number of significant advantages of the former were found relative to all these parameters.

Yuffa, A.Y.; Kucherov, A.V.; Matsenko, G.P.; Shelpakova, N.A.; Slinkin, A.A.; Vorontsova, N.V.

1986-08-01

345

Tennessee Division of Geology  

NSDL National Science Digital Library

This is the homepage of the Geology Division of the Tennessee Department of Environment and Conservation. It provides information on the division's programs, including geologic hazards research, public service, education programs, basic and applied research on geology and mineral resources, publication of geologic information, permitting of oil and gas wells, and regulation of Tennessee's oil and gas industry. Materials include a catalog of publications, maps, geologic bulletins, and the Public Information series of pamphlets; the Geology Division Newsletter; and information on the state's mineral industry. There is also a section on the Gray Fossil Site, an unusual assemblage of fossils and sedimentary geology encountered during road construction near the town of Gray, Tenessee.

346

Subsurface geology and porosity distribution, Madison Limestone and underlying formations, Powder River basin, northeastern Wyoming and southeastern Montana and adjacent areas  

USGS Publications Warehouse

To evaluate the Madison Limestone and associated rocks as potential sources for water supplies in the Powder River Basin and adjacent areas, an understanding of the geologic framework of these units, their lithologic facies patterns, the distribution of porosity zones, and the relation between porosity development and stratigraphic facies is necessary. Regionally the Madison is mainly a fossiliferous limestone. However, in broad areas of the eastern Rocky Mountains and western Great Plains, dolomite is a dominant constituent and in places the Madison is almost entirely dolomite. Within these areas maximum porosity development is found and it seems to be related to the coarser crystalline dolomite facies. The porosity development is associated with tabular and fairly continuous crystalline dolomite beds separated by non-porous limestones. The maximum porosity development in the Bighorn Dolomite, as in the Madison, is directly associated with the occurrence of a more coarsely crystalline sucrosic dolomite facies. Well data indicate, however, that where the Bighorn is present in the deeper parts of the Powder River Basin, it may be dominated by a finer crystalline dolomite facies of low porosity. The 'Winnipeg Sandstone' is a clean, generally well-sorted, medium-grained sandstone. It shows good porosity development in parts of the northern Powder River Basin and northwestern South Dakota. Because the sandstone is silica-cemented and quartzitic in areas of deep burial, good porosity is expected only where it is no deeper than a few thousand feet. The Flathead Sandstone is a predominantly quartzose, slightly feldspathic sandstone, commonly cemented with iron oxide. Like the 'Winnipeg Sandstone,' it too is silica-cemented and quartzitic in many places so that its porosity is poor in areas of deep burial. Illustrations in this report show the thickness, percent dolomite, and porosity-feet for the Bighorn Dolomite and the Madison Limestone and its subdivisions. The porosity-feet for the 'Winnipeg' and Flathead Sandstones and four regional geologic sections are also shown.

Peterson, James A.

1978-01-01

347

Bedrock Geologic Map of Maine  

NSDL National Science Digital Library

In this activity students study a map of bedrock geology which describes the types of rocks that exist in a given area. It shows these rock units as well as their known and inferred contacts. Consideration is also given to folding, faulting, unconformities, and similar rock relationships. These features are often included in bedrock geology maps. Students study the legend and scale and become aware of the other information that is included on the map such as the stratigraphic column, list of formations, and inset map of metamorphic grade. Students then locate their city or town and draw a 40-mile diameter circle around it and identify all the symbols inside the circle and the age of the various rocks. Student question sheets are available at this site. Although this activity was written for a map of Maine, it will work in any state where geological maps are available.

348

Oklahoma Geological Survey  

NSDL National Science Digital Library

The Oklahoma Geological Survey is a state agency dedicated to geological research and public service. This site contains information on earthquakes, geographic names, general Oklahoma geology, and the mountains and water resources of the state. There are educational materials available to order, many of which are free. Geologic maps indicate rock types and ages, as well as the geologic provinces of the state. Links are provided for more resources.

349

Vermont Geological Survey  

NSDL National Science Digital Library

The Vermont Geological Survey, also known as the Division of Geology and Mineral Resources in the Department of Environmental Conservation, conducts surveys and research relating to the geology, mineral resources and topography of the State. This site provides details about the states geology with a downloadable state geologic map and key, state rock information, gold in Vermont, fossils found in the state, bedrock mapping details, stream geomorphology, the Champlain thrust fault, earthquakes, radioactive waste and links for additional information.

350

Potential for a Basin-Centered Gas Accumulation in Travis Peak (Hosston) Formation, Gulf Coast Basin, U.S.A. Geologic Studies of Basin-Centered Gas Systems.  

National Technical Information Service (NTIS)

The potential of Lower Cretaceous sandstones of the Travis Peak Formation in the northern Gulf Coast Basin to harbor a basin-centered gas accumulation was evaluated by examining (1) the depositional and diagenetic history and reservoir properties of Travi...

C. E. Bartberger T. S. Dyman S. M. Condon

2003-01-01

351

Overseas Geology and Mineral Resources. Number 54: A New Lithostratigraphical and Palaeoenvironmental Interpretation for the Coralline Limestone Formations (Miocene) of the Maltese Islands.  

National Technical Information Service (NTIS)

The general stratigraphy of the Oligocene and Miocene sediments of the Maltese Islands was firmly established by Spratt (1843) and, despite revision of the formation names, has remained essentially the same up to the present. Lithostratigraphical subdivis...

H. M. Pedley

1978-01-01

352

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

353

The cost of meeting increased cooling-water demands for CO2 capture and storage utilizing non-traditional waters from geologic saline formations  

NASA Astrophysics Data System (ADS)

Deep (> ˜800 m) saline water-bearing formations in the United States have substantial pore volume that is targeted for storage of carbon dioxide (CO2) and the associated saline water can be extracted to increase CO2 storage efficiency, manage pressure build up, and create a new water source that, once treated, can be used for power-plant cooling or other purposes. Extraction, treatment and disposal costs of saline formation water to meet added water demands from CO2 capture and storage (CCS) are discussed. This underutilized water source may be important in meeting new water demand associated with CCS. For a representative natural gas combined-cycle (NGCC) power plant, simultaneous extraction of brine from the storage formation could provide enough water to meet all CCS-related cooling demands for 177 out of the 185 (96 %) saline formations analyzed in this study. Calculated total cost of water extraction, treatment and disposal is less than 4.00 US Dollars (USD) m-3 for 93 % of the 185 formations considered. In 90 % of 185 formations, treated water costs are less than 10.00 USD tonne-1 of CO2 injected. On average, this represents approximately 6 % of the total CO2 capture and injection costs for the NGCC scenario.

Klise, Geoffrey T.; Roach, Jesse D.; Kobos, Peter H.; Heath, Jason E.; Gutierrez, Karen A.

2013-05-01

354

Ultra-deep oxidation and exotic copper formation at the late pliocene boyongan and bayugo porphyry copper-gold deposits, surigao, philippines: Geology, mineralogy, paleoaltimetry, and their implications for Geologic, physiographic, and tectonic controls  

USGS Publications Warehouse

The Boyongan and Bayugo porphyry copper-gold deposits are part of an emerging belt of intrusion-centered gold-rich deposits in the Surigao district of northeast Mindanao, Philippines. Exhumation and weathering of these Late Pliocene-age deposits has led to the development of the world's deepest known porphyry oxidation profile at Boyongan (600 m), and yet only a modest (30-70 m) oxidation profile at adjacent Bayugo. Debris flows, volcanic rocks, and fluviolacustrine sediments accumulating in the actively extending Mainit graben subsequently covered the deposits and preserved the supergene profiles. At Boyongan and Bayugo, there is a vertical transition from shallower supergene copper oxide minerals (malachite + azurite + cuprite) to deeper sulfide-stable assemblages (chalcocite ?? hypogene sulfides). This transition provides a time-integrated proxy for the position of the water table at the base of the saturated zone during supergene oxidation. Contours of the elevation of the paleopotentiometric surface based on this min- eralogical transition show that the thickest portions of the unsaturated zone coincided with a silt-sand matrix diatreme breccia complex at Boyongan. Within the breccia complex, the thickness of the unsaturated zone approached 600 in, whereas outside the breccia complex (e.g., at Bayugo), the thickness averaged 50 m. Contours of the paleopotentiometric surface suggest that during weathering, groundwater flowed into the breccia complex from the north, south, and east, and exited along a high permeability zone to the west. The high relief (>550 m) on the elevation of the paleopotentiometric surface is consistent with an environment of high topographic relief, and the outflow zone to the west of the breccia complex probably reflects proximity to a steep scarp intersecting the western breccia complex margin. Stable isotope paleoaltimetry has enabled estimation of the elevation of the land surface, which further constrains the physiographic setting during supergene oxidation. Isotopic measurements of oxygen in supergene kaolinite from Boyongan suggest that local paleometeoric water involved in weathering had a ??180 composition of approximately -5.7 per mil. At the latitude of the southern Philippines, this value corresponds to Pleistocene rain water condensing at elevations between 750 and 1,050 m above contemporary sea level, providing a maximum estimate for the surface elevation during weathering of the porphyry systems. Physiographic reconstuctions suggest that the deep oxidation profile at Boyongan formed in an environment of high topographic relief immediately east of a prominent (>550 m) escarpment. The high permeability contrast between the breccia complex and the surrounding wall rocks, coupled with the proximity of the breccia complex to the escarpment, led to a depressed groundwater table and a vertically extensive unsaturated zone in the immediate vicinity of Boyongan. This thick vadose zone and the low hypogene pyrite/copper sulfide ratios (0.6) at Boyongan promoted in situ oxidation of copper sulfides with only modest (<200 m) supergene remobilization of copper. In contrast, higher hypogene pyrite/chalcopyrite ratios (2.3) at Bayugo led to greater acid production during weathering and more complete leaching of copper above the base of oxidation. This process promoted significant (600 m) lateral dispersion of copper down the paleohydraulic gradient into the diatreme breccia comple, ultimately leading to the formation of an exotic copper deposit. ?? 2009 Society of Economices Geologists, Inc.

Braxton, D. P.; Cooke, D. R.; Ignacio, A. M.; Rye, R. O.; Waters, P. J.

2009-01-01

355

Geology of the northern Cleft segment, Juan de Fuca Ridge: Recent lava flows, sea-floor spreading, and the formation of megaplumes  

SciTech Connect

Geologic mapping and lava sampling were carried out after the discovery of large bursts of hydrothermal fluids (megaplumes) over the southern Juan de Fuca Ridge in 1986 and 1987. These investigations of the northernmost section of the Cleft segment have discovered: (1) semicontinuous low-temperature venting and one major high-temperature vent site along 17 km of the neovolcanic zone and (2) very glassy, lightly sedimented sheet flows and pillow mounds superimposed on older terrain over about 24 km along the northern-most part. The pillow mounds are documented to have erupted between 1981 and 1987. The occurrence of the megaplumes during this same time period strengthens the hypothesis that megaplumes are caused by sea-floor extension events. Although the basalts from the entire length of the neovolcanic zone of the Cleft segment appear to have been derived from the same mantle source, a systematic northward increase in Mg number along the segment within the neovolcanic zone indicates less shallow-level differentiation to the north, possibly related to the development of new magma chambers during the recent phase of sea-floor spreading that has occurred there.

Embley, R.W. (NOAA, Newport, OR (United States)); Chadwick, W. (Oregon State Univ., Newport (United States)); Perfit, M.R. (Univ. of Florida, Gainesville (United States)); Baker, E.T. (Pacific Marine Environmental Lab., Seattle, WA (United States))

1991-08-01

356

Kentucky Geological Survey  

NSDL National Science Digital Library

The University of Kentucky maintains the Kentucky Geological Survey Web site. Visitors will find a number of educational general information pages on rocks and minerals, fossils, coal, geologic hazards, industrial minerals, maps and GIS, oil and natural gas, and water, as well as the general geology of Kentucky. Each page contains specific information, data, and research summaries from the university. The geology of Kentucky page, for example, shows a map of geologic periods and gives descriptions of the rock strata in the state, a description of its landforms, and a geological photo album of physiographic regions and points of interest.

1997-01-01

357

Testing the Injectivity of CO2 in a Sub-surface Heterogeneous Reservoir  

NASA Astrophysics Data System (ADS)

This case study on subsurface reservoir characterization, considers the effect of geological heterogeneities on the storage capacity and injectivity of the Johansen Formation, which is a deep, saline aquifer underlying the Troll Gas Field off the Norwegian coast. The Johansen Formation has been interpreted as a sandy, prograding unit, deposited in a shallow marine environment during Early Jurassic time, and is overlain by a shaly unit; the Amundsen Formation. It appears as a wedge shaped sandstone body, up to 140m thick, with an areal extent in the order of 10 000 km2. The Johansen Formation is currently being considered for large scale CO2 storage from two gas power plants situated on the west coast of Norway, both of which will operate with full scale CO2 handling, as proposed by Norwegian authorities. The storage capacity needed is in the order of 3 Mt CO2/year. With access to a new 3D seismic survey (Gassnova, 2010), and based on existing well log data from 25 penetrating wells, we have studied large scale geometries and intra-formational features, and built a geo-conceptual model of the Johansen Formation. The reservoir is heterogeneous, with distinct permeability zonation within clinothems separated by less permeable layers. In order to obtain better understanding of crucial reservoir parameters and supplement limited data, comparison of data from easily accessible analogue rock units is useful. For this purpose the unit should be well exposed and thoroughly documented, such as the Panther Tongue Member (Star Point Formation, Mesa Verde Group) in Book Cliffs, from which we have collected some comparable permeability estimates for the model. On a micro scale, mineralogy, grain size/shape and pore geometry constitue major controls on reservoir porosity and permeability. Direct geological information is at this point in time limited to a few meters of core, from which detailed mineralogical information has been derived (optical microscopy, SEM, XRD), and some additional data from side wall cores and cuttings. From this we evaluate facies dependence related to observed diagenetic features and compositional variations due to burial depth (2-4km), mainly considering chlorite coatings (preserving porosity) and cementation (calcite and quartz). Using Schlumberger soft-wares; Petrel (reservoir) and Eclipse (fluid flow), we are testing injection scenarios (one point, several points, bleeding wells) in several intra-formational geological settings. These results will be evaluated relative to the distribution of facies and heterogeneities in the reservoir, considering multiphase flow given the local pressure regime.

Sundal, A.; Nystuen, J.; Dypvik, H.; Aagaard, P.

2011-12-01

358

Geology, Uranium Deposits, and Uranium Favorability of the Hartford Hill Rhyolite and Truckee Formation, Southwestern Washoe County, Nevada, and Eastern Lassen County, California.  

National Technical Information Service (NTIS)

The Hartford Hill Rhyoliteis a series of ash-flow sheets that range in age from late Oligocene to early Miocene. This series attains a maximum stratigraphic thickness of approximately 4,000 ft. The Truckee Formation is a sequence of alternating lacustrine...

G. M. Cupp S. H. Leedom T. P. Mitchell D. R. Allen

1977-01-01

359

Geology of the Fox Hills Formation (Late Cretaceous) in the Williston Basin of North Dakota, with Reference to Uranium Potential. Report of Investigation No. 55.  

National Technical Information Service (NTIS)

The Fox Hills Formation is a marine and brackish sequence of primarily medium and fine clastics within the Late Cretaceous Montana Group. In the Williston basin of North Dakota, four members (in ascending order) are recognized: Trail City, Timber Lake, Ir...

A. M. Cvancara

1976-01-01

360

Geology of the Fox Hills Formation (late Cretaceous) in the Williston Basin of North Dakota, with reference to uranium potential. Report of investigation No. 55  

Microsoft Academic Search

The Fox Hills Formation is a marine and brackish sequence of primarily medium and fine clastics within the Late Cretaceous Montana Group. In the Williston basin of North Dakota, four members (in ascending order) are recognized: Trail City, Timber Lake, Iron Lightning (with Bullhead and Colgate lithofacies), and Linton. The Fox Hills conformably overlies the Pierre Shale and conformably and

Cvancara

1976-01-01

361

Geophysics & Geology Inspected.  

ERIC Educational Resources Information Center

Summarizes findings of a recently published report of the Canadian Geoscience Council, which includes the following topics regarding college geology: facilities; teaching; undergraduate enrollments; postgraduate enrollments; geologic research; and integration of Canadian geoscience with other countries. (CS)

Neale, E. R. W.

1981-01-01

362

GSA Geologic Time Scale  

NSDL National Science Digital Library

This Geological Society of America (GSA) site contains a detailed geologic time scale as an educational resource. It may be downloaded to a larger size, and includes all Eras, Eons, Periods, Epochs and ages as well as magnetic polarity information.

1999-01-01

363

Geologic Report for the Beaufort Sea Planning Area, Alaska: Regional Geology, Petroleum Geology, Environmental Geology.  

National Technical Information Service (NTIS)

The 192-page report provides a summary of the geologic framework, hydrocarbon potential, and physical environment of the offshore area tentatively scheduled for Federal OCS (Outer Continental Shelf) Oil and Gas Lease Sale 97. The geologic interpretation i...

J. D. Craig K. W. Sherwood P. P. Johnson

1985-01-01

364

Geologic spatial analysis  

SciTech Connect

This report describes the development of geologic spatial analysis research which focuses on conducting comprehensive three-dimensional analysis of regions using geologic data sets that can be referenced by latitude, longitude, and elevation/depth. (CBS)

Thiessen, R.L.; Eliason, J.R.

1989-01-01

365

National Assessment of Geologic Carbon Dioxide Storage Resources - Results.  

National Technical Information Service (NTIS)

In 2012, the U.S. Geological Survey (USGS) completed an assessment of the technically accessible storage resources (TASR) for carbon dioxide (CO2) in geologic formations underlying the onshore and State waters area of the United States. The formations ass...

2013-01-01

366

On leakage and seepage from geological carbon sequestration sites  

Microsoft Academic Search

Geologic carbon sequestration is one strategy for reducing the rate of increase of global atmospheric carbon dioxide (COâ ) concentrations (IEA, 1997; Reichle, 2000). As used here, the term geologic carbon sequestration refers to the direct injection of supercritical COâ deep into subsurface target formations. These target formations will typically be either depleted oil and gas reservoirs, or brine-filled permeable

C. M. Oldenburg; A. J. A. Unger; R. P. Hepple; P. D. Jordan

2002-01-01

367

Louisiana Geological Survey  

NSDL National Science Digital Library

The Louisiana Geological Survey, located at Louisiana State University, developed this website to promote its goal to provide geological and environmental data that will allow for environmentally sound natural resource development and economic decisions. Users can find general information about the Survey's mission, staff, plan, and history. The website features the research and publications of the Basin Research, Cartographic, Coastal, Geologic Mapping, and Water and Environmental sections. Researchers can discover stratigraphic charts of Louisiana, information on lignite resources, and other geologic data.

368

South Carolina Geological Survey  

NSDL National Science Digital Library

The South Carolina Geological Survey (SCGS) homepage contains information about state mapping, education and outreach programs, and recent news. For educators, there is the Earth Science education series of publications which includes presentations and page-size graphics on such topics as earthquakes, plate tectonics, geologic time, fossils, and others. Other materials include information on mineral resources, links to organizations in and about South Carolina geology, the South Carolina core repository, the Geologic Map of South Carolina, and others.

369

Marine geology: A planet earth perspective  

SciTech Connect

This text provides coverage of the basic geology of the marine development. It starts with the formation of the oceans using plate tectonics, continues with discussions of the mid-ocean ridges, and concludes with coverage of the formation and deformation of the continents.

Anderson, R.N.

1986-01-01

370

Modeling geologic storage of carbon dioxide: Comparison ofnon-hysteretic and hysteretic characteristic curves  

SciTech Connect

Numerical models of geologic storage of carbon dioxide (CO2)in brine-bearing formations use characteristic curves to represent theinteractions of non-wetting-phase CO2 and wetting-phase brine. When aproblem includes both injection of CO2 (a drainage process) and itssubsequent post-injection evolution (a combination of drainage andwetting), hysteretic characteristic curves are required to correctlycapture the behavior of the CO2 plume. In the hysteretic formulation,capillary pressure and relative permeability depend not only on thecurrent grid-block saturation, but also on the history of the saturationin the grid block. For a problem that involves only drainage or onlywetting, a non-hysteretic formulation, in which capillary pressure andrelative permeability depend only on the current value of the grid-blocksaturation, is adequate. For the hysteretic formulation to be robustcomputationally, care must be taken to ensure the differentiability ofthe characteristic curves both within and beyond the turning-pointsaturations where transitions between branches of the curves occur. Twoexample problems involving geologic CO2 storage are simulated withTOUGH2, a multiphase, multicomponent code for flow and transport codethrough geological media. Both non-hysteretic and hysteretic formulationsare used, to illustrate the applicability and limitations ofnon-hysteretic methods.The first application considers leakage of CO2from the storage formation to the ground surface, while the secondexamines the role of heterogeneity within the storageformation.

Doughty, Christine

2006-07-17

371

Geological Survey Program  

NSDL National Science Digital Library

If your research or interests lie in the geology of South Dakota, then the state's Geological Survey Program Web site is for you. Offered are online publications and maps, a geologic reference database, a lithologic logs database, digital base maps, a water quality database, and several other quality information sources worth checking out.

372

Analysis of Geological Structures  

Microsoft Academic Search

A knowledge of structural geology is fundamental to understanding the processes by which the earth's crust has evolved. It is a subject of fundamental importance to students of geology, experienced field geologists and academic researchers as well as to petroleum and mining engineers. In contrast to many structural textbooks which dwell upon geometrical descriptions of geological structures, this book emphasises

Neville J. Price; John W. Cosgrove

1990-01-01

373

Teaching Sedimentary Geology  

NSDL National Science Digital Library

This site contains a variety of resources for faculty members who teach undergraduate sedimentary geology. You will find links to a growing collection of activities and assignments, internet and computer resources, useful articles, presentations from the summer 2006 workshop on teaching sedimentary geology, and lots of creative ideas for teaching sedimentary geology.

374

Estimation of the hydraulic parameters of a confined geologic formation from slug test in fully penetrating well using a complete quasi-steady flow model in a forward and in an inverse optimal estimation procedure  

NASA Astrophysics Data System (ADS)

Slug tests offer a fast and inexpensive means of estimating the hydraulic parameters of a geologic formation, and are very well suited for contaminated site assessment because no water is essentially withdrawn. In the great majority of slug tests performed in wells fully penetrating confined geologic formations, and for over-damped conditions, the response data are evaluated with the transient-flow model of Cooper et al. (1967) when the radial hydraulic conductivity Kr and the coefficient of specific storage Ss are to be estimated. That particular analytical solution, however, is computationally involved and awkward to use. Thus, groundwater professionals often use a few pre-prepared type-curves to fit the data by a rough matching procedure, visually or computationally. On the other hand, the method of Hvorslev (1951), which assumes the flow to be quasi-steady, is much simpler but yields only Kr-estimates. Koussis and Akylas (2012) have derived a complete quasi-steady flow model that includes a storage balance inside the aquifer and allows estimating both Kr and Ss, through matching of the well response data to a (dimensionless) type-curve. That model approximates the model of Cooper et al. closely and has the practical advantage that its solution type-curves are generated very simply, even using an electronic spreadsheet. Thus, an optimal fit of data by a type-curve can be readily embedded in an exhaustive search. That forward procedure, however, is semi-automated; it involves repeated computation of the quasi-steady flow solution, until finding an optimal pair of Kr and Ss values, according to some formal criterion of optimality, or visually. In addition, we have developed a fully automated inverse procedure for estimating the optimal hydraulic formation parameters Kr and Ss. We test and compare these two parameter estimation methods for the slug test and discuss their strengths and weaknesses. Cooper, H. H., Jr., J. D. Bredehoeft and I. S. Papadopulos. 1967. Response of a finite-diameter well to an instantaneous charge of water, Water Resour. Res., 3(1): 263-269. Koussis A. D. and E. Akylas (2012) Slug test analysis for confined aquifers in the over-damped case: Quasi-steady flow model, with estimation of the specific storage coefficient, Ground Water, 50(4): 608-613.

Rozos, Evangelos; Akylas, Evangelos; Koussis, Antonis D.

2013-04-01

375

Digital geologic map and GIS database of Venezuela  

USGS Publications Warehouse

The digital geologic map and GIS database of Venezuela captures GIS compatible geologic and hydrologic data from the 'Geologic Shaded Relief Map of Venezuela,' which was released online as U.S. Geological Survey Open-File Report 2005-1038. Digital datasets and corresponding metadata files are stored in ESRI geodatabase format; accessible via ArcGIS 9.X. Feature classes in the geodatabase include geologic unit polygons, open water polygons, coincident geologic unit linework (contacts, faults, etc.) and non-coincident geologic unit linework (folds, drainage networks, etc.). Geologic unit polygon data were attributed for age, name, and lithologic type following the Lexico Estratigrafico de Venezuela. All digital datasets were captured from source data at 1:750,000. Although users may view and analyze data at varying scales, the authors make no guarantee as to the accuracy of the data at scales larger than 1:750,000.

Garrity, Christopher P.; Hackley, Paul C.; Urbani, Franco

2006-01-01

376

Geology Fieldnotes: Bryce Canyon National Park, Utah  

NSDL National Science Digital Library

Located on the Colorado Plateau in Utah, this canyon is comprised mostly of sedimentary rocks, and continues to be eroded and shaped by the Paria River. Its geologic and human history are outlined on this site, including the formation of the canyon, from the Cretaceous period (144 million years ago) to the present, and geologic features, such as fins, columns, pinnacles, and hoodoos. Visitor information, links to other resources, maps, and a teacher feature (resources for teaching geology with National Park examples) are also available.

Foos, Annabelle

377

Geologic history of Mars  

NASA Astrophysics Data System (ADS)

Mars accumulated and differentiated into crust, mantle and core within a few tens of millions of years of Solar System formation. Formation of Hellas, which has been adopted as the base of the Noachian period, is estimated to have occurred around 4.1 to 3.8 Gyr ago, depending on whether or not the planet experienced a late cataclysm. Little is known of the pre-Noachian period except that it was characterized by a magnetic field, subject to numerous large basin-forming impacts, probably including one that formed the global dichotomy. The Noachian period, which ended around 3.7 Gyr ago, was characterized by high rates of cratering, erosion, and valley formation. Most of Tharsis formed and surface conditions were at least episodically such as to cause widespread production of hydrous weathering products such as phyllosilicates. Extensive sulfate deposits accumulated late in the era. Average erosion rates, though high compared with later epochs, fell short of the lowest average terrestrial rates. The record suggests that warm, wet conditions necessary for fluvial activity were met only occasionally, such as might occur if caused by large impacts or volcanic eruptions. At the end of the Noachian, rates of impact, valley formation, weathering, and erosion all dropped precipitously but volcanism continued at a relatively high average rate throughout the Hesperian, resulting in the resurfacing of at least 30% of the planet. Large water floods formed episodically, possibly leaving behind large bodies of water. The canyons formed. The observations suggest the change at the end of the Noachian suppressed most aqueous activity at the surface other than large floods, and resulted in growth of a thick cryosphere. However, presence of discrete sulfate rich deposits, sulfate concentrations in soils, and occasional presence of Hesperian valley networks indicates that water activity did not decline to zero. After the end of the Hesperian around 3 Gyr ago the pace of geologic activity slowed further. The average rate of volcanism during the Amazonian was approximately a factor of ten lower than in the Hesperian and activity was confined largely to Tharsis and Elysium. The main era of water flooding was over, although small floods occurred episodically until geologically recent times. Canyon development was largely restricted to formation of large landslides. Erosion and weathering rates remained extremely low. The most distinctive characteristic of the Amazonian is formation of features that have been attributed to the presence, accumulation, and movement of ice. Included are the polar layered deposits, glacial deposits on volcanoes, ice-rich veneers at high latitudes, and a variety of landforms in the 30-55° latitude belts, including lobate debris aprons, lineated valley fill and concentric crater fill. Most of the gullies on steep slopes also formed late in this era. The rate of formation of the ice-related features and the gullies probably varied as changes in obliquity affected the ice stability relations.

Carr, Michael H.; Head, James W.

2010-06-01

378

Utah Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Utah Geological Survey. Materials available here include news articles and information on geologic hazards; information on places of geological interest; and popular geology topics such as earthquakes, rocks and minerals, fossils, economic resources, groundwater resources, and others. Educational resources include teaching kits, the 'Teacher's Corner' column in the survey's newsletter, and a series of 'Glad You Asked' articles on state geological topics. There is also an extensive list of free K-12 educational materials, as well as a set of curriculum materials such as activity packets, slide shows, and teachers' handbooks, which are available to order.

2011-03-30

379

Geology of Kentucky  

NSDL National Science Digital Library

This website contains geologic maps of Kentucky, with a discussion of geologic time in regards to the rocks, minerals, fossils, and economic deposits found there. There are also sections that describe strata and geologic structures beneath the surface (faults, basins, and arches), the structural processes (folding and faulting) that create stratigraphic units, the geomorphology of the state, geologic information by county, a general description of geologic time, fossil, rocks, and minerals of Kentucky, and a virtual field trip through Natural Bridges State Park. Links are provided for further information.

380

Virtual-Geology.Info  

NSDL National Science Digital Library

At virtual-geology.info, Roger Suthren, a professor at Oxford Brookes University, offers educational materials on geologic phenomena throughout the world. Users can take virtual field trips to study the geology of Scotland, Alaska, and France. In the Regional Geology link, visitors can view wonderful pictures of the volcanoes of Germany, Italy, France, and Greece. Educators can find images of sediments and sedimentary rocks which can be used in a variety of classroom exercises. The website supplies descriptions and additional educational links about sedimentology and environmental geology.

381

Seismic response in heterogeneous media.  

NASA Astrophysics Data System (ADS)

One of the aims of our research in the last few years has been to try to establish a comprehensive knowledge of the seismic response in heterogeneous media. There are many situations in geophysical exploration, where the interpreter, having to face seismic data acquired and processed with standard methods, has very little to interpret below heterogeneous layers. Basalts are an example of highly heterogenous media. Examination of flood basalts in the field show a high level of heterogeneity. The individual flows are highly fractured and are separated by layers of unconsolidated ash and clay. The top and bottom surfaces of the flows are highly irregular with each flow filling in topography on the previous flow. We used geological observations on basalts and defined models using statistical properties derived from basalts. However our results are applicable to any target imaging beneath strongly scattering structures. We have worked on highly heterogeneous models derived from borehole log data, digital imagery and seismic data. Through synthetic simulations, we have investigated the wave propagation through highly heterogeneous layers. It is the wave scattering through these heterogeneities (body and interface) that obscures underlying structures. Scattering from rough interfaces seems to have the most detrimental effect on imaging at depth, creating a serious distortion to the wavefront. Body scattering becomes more important with increasing thickness of the layer (number of wavelengths in the thickness). Also, as heterogeneity increases, the higher frequencies will get preferentially scattered. Only the lower frequencies retain the coherency necessary for successful imaging at the target. All this information is extremely useful both at the acquisition and processing stages. In summary, the coherent seismic wave that passes through a heterogenous layer preferentially loses high frequency energy, and in addition the wavefield is highly attenuated, distorted, and is seriously contaminated by the scattered energy. More detailed wave attenuation studies are currently part of our research work. Having already seen that highly absorbing layers can improve the imaging of lower structures, we are now focusing our attention on measuring the (scattering and intrinsic) attenuation, on both synthetic and real data.

Martini, F.; Bean, C. J.

2003-04-01

382

Thermodynamic Properties of Magnesium Chloride Hydroxide Hydrate (Mg3Cl(OH)5:4H2O, Phase 5), and Its importance to Nuclear Waste Isolation in Geological Repositories in Salt Formations  

NASA Astrophysics Data System (ADS)

MgO (bulk, pure MgO corresponding to the mineral periclase) is the only engineered barrier certified by the Environmental Protection Agency for emplacement in the Waste Isolation Pilot Plant (WIPP) in the US, and an Mg(OH)2-based engineered barrier (bulk, pure Mg(OH)2 corresponding to brucite) is to be employed in the Asse repository in Germany. Both the WIPP and the Asse are located in salt formations. The WIPP is a U.S. Department of Energy geological repository being used for the permanent disposal of defense-related transuranic waste (TRU waste). The repository is 655 m below the surface, and is situated in the Salado Formation, a Permian salt bed mainly composed of halite, and of lesser amounts of polyhalite, anhydrite, gypsum, magnesite, clays and quartz. The WIPP Generic Weep Brine (GWB), a Na-Mg-Cl dominated brine, is associated with the Salado Formation. The previous vendor for MgO for the WIPP was Premier Chemicals and the current vendor is Martin Marietta Materials. Experimental studies of both Premier MgO and Martin Marietta MgO with the GWB at SNL indicate the formation of magnesium chloride hydroxide hydrate, Mg3Cl(OH)5:4H2O, termed as phase 5. However, this important phase is lacking in the existing thermodynamic database. In this study, the solubility constant of phase 5 is determined from a series of solubility experiments in MgCl2-NaCl solutions. The solubility constant at 25 oC for the following reaction, Mg3Cl(OH)5:4H2O + 5H+ = 3Mg2+ + 9H2O(l) + Cl- is recommended as 43.21±0.33 (2?) based on the Specific Interaction Theory (SIT) model for extrapolation to infinite dilution. The log K obtained via the Pitzer equations is identical to the above value within the quoted uncertainty. The Gibbs free energy and enthalpy of formation for phase 5 at 25 oC are derived as -3384±2 (2?) kJ mol-1 and -3896±6 (2?) kJ mol-1, respectively. The standard entropy and heat capacity of phase 5 at 25 oC are estimated as 393±20 J mol-1 K-1 and 374±19 J mol-1 K-1, respectively. Phase 5, and its similar phase, phase 3 (Mg2Cl(OH)3:4H2O), could have a significant role in influencing the geochemical conditions in geological repositories for nuclear waste in salt formations where MgO or brucite is employed as engineered barriers, when Na-Mg-Cl dominated brines react with MgO or brucite. Based on our solubility constant for phase 5 in combination with the literature value for phase 3, we predict that the composition for the invariant point of phase 5 and phase 3 would be mMg = 1.70 and pmH = 8.93 in the Mg-Cl binary system. The recent WIPP Compliance Recertification Application PA Baseline Calculations indicate that phase 5 instead of phase 3 is indeed a stable phase when GWB equilibrates with actinide-source-term phases, brucite, magnesium carbonates, halite and anhydrite. 1. This research is funded by WIPP programs administered by the U.S. Department of Energy. 2. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

Xiong, Y.; Deng, H.; Nemer, M. B.; Johnsen, S.

2009-12-01

383

Ohio Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Ohio Geological Survey. Materials available through the site include a variety of publications, particularly the Survey's reports, bulletins, information circulars, guidebooks, and many others. There is an extensive selection of maps, including topographic maps in several scales, and downloadable geologic maps of several themes (drift thickness, bedrock geology, karst areas, glacial geology, and many others), as well as digital maps and data. The interactive maps section features online map viewers of abandoned mines, earthquake epicenters, surficial geology, geology of Lake Erie, and others. The educational resources page has links to the 'Hands On Earth' series of activities, GeoFacts (short bulletins on Ohio geological topics), nontechnical educational leaflets, field guides, and links to other publications, rock and mineral clubs, educational associations, and related websites. There is also a link to the Ohio Seismic Network, a network of seismograph stations located at colleges, universities, and other institutions that collects and disseminates information about earthquakes in Ohio.

384

Geologic assessment of natural gas from coal seams in the raton and vermejo formations, raton basin. Topical report, January 1991-June 1992  

SciTech Connect

The coalbed methane resources of the Raton basin were assessed through an analysis of public and proprietary data sources covering stratigraphic, structural, hydrologic, coal rank, and gas content data. The total volume of methane contained in Raton and Vermejo Formation coal seams is estimated to range from 8.4 to 12.1 trillion cubic feet (Tcf), with a mean estimate of 10.2 Tcf. The highest coalbed methane resource concentration occurs in the deep trough around the town of La Veta. The second highest resource concentration occurs southeast of Vermejo Park. Successful development will need to consider favorable coal seam geometry, depth, and reservoir properties in addition to the in-place resource. The study recommends future research of complex parameters affecting coalbed methane producibility in the area.

Stevens, S.H.; Lombardi, T.E.; Kelso, B.S.; Coates, J.M.

1992-06-01

385

3-D seismic delineation and geologic explanation of channelization in the Frio Formation of Javelina/East McCook Field, Hidalgo County, Texas  

SciTech Connect

Sinuous, channel-form features were recognized on seismic amplitude time-slice maps of the shallow Oligocene Frio Formation on several Shell proprietary 3-D seismic surveys in west-central Hidalgo County, Texas. A case study of channel morphologies observed in the Frio Formation within the 50 mi{sup 2} 3-D seismic survey over Javelina/East McCook field was undertaken to better understand the distribution, lithology, origin, and hydrocarbon potential of these features. Ten separate channel-like amplitude features are observed in flattened time slices within a 200 m (approximately 1100 ft) interval on 3-D seismic. The channels have various azimuthal orientations and varying degrees of sinuosity. Several of the features have lengths that span the 3-D survey area (10 mi); apparent channel widths range from 200 to 2000 ft. The channelized seismic events tie to an interval of interbedded mudstones and claystones with siltstones. Two of the channels seen on seismic, and which were penetrated by wells, correlate to siftstone and mudstone intervals that have gross thicknesses of 30 to 60 ft. The lithologies and dimensions of the two channels indicate that they are probably small mudstone/siltstone-filled tributary/distributary channels deposited in a coastal floodplain environment; a comparison of the apparent channel dimensions to the dimensions of small channels/bayous of the modern-day Texas Gulf Coast supports this interpretation. Correlation of wells adjacent to the channels indicates that sandy point-bar facies are not present in association with the channel fill, which discounts the idea that high-quality reservoirs are flanking these particular mud-filled channels.

Gibson, J.L. [Shell Western Exploration and Production, Inc., Houston, TX (United States)

1994-09-01

386

Approach for interoperability of multi-source geological hazard data based on ontology and GeoSciML  

Microsoft Academic Search

Sorts of models in current geological hazard information management system and digital disaster reduction system (DDRS) in China still lack of enough basic data support. One key problem is how to realize integration and share of complex geological hazard heterogenous spatial information. Isomerous geological hazard data have four types: structural isomer, syntax isomer, system isomer and semantic isomer. Interoperability of

Gang Liu; Chonglong Wu; Xiaogang Ma; Yanni Wang; Fei Tian

2009-01-01

387

A simple screening model for selecting CO2 sequestration sites using a semi-analytical model for calculating pressure buildup and phase front movement in thick and heterogeneous geologic settings  

NASA Astrophysics Data System (ADS)

A semi-analytical solution developed by Kumar et al. (2009) has been updated to include multiple rock layers, an expanding constant pressure boundary, and an updated phase front definition. The two phase fronts that are calculated include a dry zone region detailed by Noh et al. (2004) and a two phase region. The semi-analytical model calculates the well pressure needed to inject CO2 at a constant rate at a specified time and the movement of the phase fronts. The updated semi-analytical model can be used for several applications; namely for complex sandstone layering formations, large storage reservoirs, and for quick and easy screening of potential CO2 storage sites. Numerical solutions require significant reservoir characterization effort and simulation time to complete. The updated semi-analytical model can be used with limited reservoir data to estimate well pressure expectations and phase front movements. The algorithm developed by Kumar et al. (2004) can be implemented with transient, steady-state, and pseudo-steady state flow equations. The updated model assumes early-transient flow equations for initialization and steady-state flow equations for later time with a constant pressure boundary. The updated semi-analytical model has been applied to a simplified CO2 storage reservoir and the results have been compared to a comparable TOUGH2 model. The pressure buildup results, defined as the difference between the well pressure and initial reservoir pressure, and two phase front movement and the dry zone front movement show reasonable agreement with some differences.

Sargent, W.; Benson, S.

2012-04-01

388

Preliminary Geologic Characterization of West Coast States for Geologic Sequestration  

SciTech Connect

Characterization of geological sinks for sequestration of CO{sub 2} in California, Nevada, Oregon, and Washington was carried out as part of Phase I of the West Coast Regional Carbon Sequestration Partnership (WESTCARB) project. Results show that there are geologic storage opportunities in the region within each of the following major technology areas: saline formations, oil and gas reservoirs, and coal beds. The work focused on sedimentary basins as the initial most-promising targets for geologic sequestration. Geographical Information System (GIS) layers showing sedimentary basins and oil, gas, and coal fields in those basins were developed. The GIS layers were attributed with information on the subsurface, including sediment thickness, presence and depth of porous and permeable sandstones, and, where available, reservoir properties. California offers outstanding sequestration opportunities because of its large capacity and the potential of value-added benefits from enhanced oil recovery (EOR) and enhanced gas recovery (EGR). The estimate for storage capacity of saline formations in the ten largest basins in California ranges from about 150 to about 500 Gt of CO{sub 2}, depending on assumptions about the fraction of the formations used and the fraction of the pore volume filled with separate-phase CO{sub 2}. Potential CO{sub 2}-EOR storage was estimated to be 3.4 Gt, based on a screening of reservoirs using depth, an API gravity cutoff, and cumulative oil produced. The cumulative production from gas reservoirs (screened by depth) suggests a CO{sub 2} storage capacity of 1.7 Gt. In Oregon and Washington, sedimentary basins along the coast also offer sequestration opportunities. Of particular interest is the Puget Trough Basin, which contains up to 1,130 m (3,700 ft) of unconsolidated sediments overlying up to 3,050 m (10,000 ft) of Tertiary sedimentary rocks. The Puget Trough Basin also contains deep coal formations, which are sequestration targets and may have potential for enhanced coal bed methane recovery (ECBM).

Larry Myer

2005-09-29

389

Evaluation of the geological relationships to gas hydrate formation and stability. Annual technical progress report, October 1, 1984--September 30, 1985  

SciTech Connect

During the reported year we have enhanced our knowledge on and gained considerable experience in assessment of the gas hydrate resources in the offshore environments. Specifically, we have learned and gained experience in the following: Efficiently locating data sources, including published literature and unpublished information. We have established personal communication extremely critical in data accessability and acquisition. We have updated information pertinent to gas hydrate knowledge, also based on thorough study and evaluation of most Russian literature and additional publications in languages other than English. Besides critical evaluation of widely spread literature, in many cases our reports include previously unpublished information (e.g. BSRs from the Gulf of Mexico). The assessment of the gas resources potential associated with the gas hydrates, although in most cases at a low level of confidence, appears also very encouraging for further, more detailed, study. We are also confident that, because of the present reports` format, new data and a concept-oriented approach, the result of our study will be of strong interest to various industries, research institutions and numerous governmental agencies.

Not Available

1985-12-31

390

IMPACTS OF ANTHROPOGENIC EMISSIONS IN THE SOUTHEASTERN U.S. ON HETEROGENEOUS CHEMISTRY OF ISOPRENE-DERIVED EPOXIDES LEADING TO SECONDARY ORGANIC AEROSOL FORMATION  

EPA Science Inventory

The proposed activities will yield the formulation of parameterizations that can be incorporated into SOA models that will lead to improvement in the ability to simulate isoprene SOA formation in the southeastern U. S. Specific results include: (1) characterization of reaction...

391

Metabolic heterogeneity in the formation of low density lipoprotein from very low density lipoprotein in the rat: evidence for the independent production of a low density lipoprotein subfraction  

Microsoft Academic Search

The formation of low density lipoprotein (LDL) from very low density lipoprotein (VLDL) was studied after injecting 14C-radiomethylated or '251-radioiodinated VLDL into rats. VLDL and LDL B apoprotein specific radioactivity time curves were obtained after tetramethyl- urea extraction of the lipoproteins. In all experiments, the specific activity of LDL B apoprotein did not inter- cept the VLDL curve at maximal

Noel H. Fidge; Parissa Poulis

392

Geology of the reading prong  

SciTech Connect

For over a billion years the geological terrain now called New Jersey has been the site of unusually high uranium concentrations. Although the highest of these concentrations occurs in the Reading Prong, the area is itself only part of a larger geologic province extending to the northeast and southwest. The rocks in the Reading Prong are not uniformly radioactive. High uranium concentrations tend to be associated with magnetite deposits - metamorphic equivalents of iron-rich formations - and with pegmatites - rocks formed by precipitation from mineralizing solutions in the late phases of granite emplacement. Because of the way they were formed, the uranium-bearing magnetite and pegmatite bodies tend to be long and narrow, and the resulting patterns of radon occurrence can be expected to be the same. This may explain why, in some places, adjacent houses have very different radon concentrations.

Schutz, D.

1987-03-01

393

Geologic mapping of Europa  

USGS Publications Warehouse

Galileo data enable the major geological units, structures, and surface features to be identified on Europa. These include five primary units (plains, chaos, band, ridge, and crater materials) and their subunits, along with various tectonic structures such as faults. Plains units are the most widespread. Ridged plains material spans a wide range of geological ages, including the oldest recognizable features on Europa, and appears to represent a style of tectonic resurfacing, rather than cryovolcanism. Smooth plains material typically embays other terrains and units, possibly as a type of fluid emplacement, and is among the youngest material units observed. At global scales, plains are typically mapped as undifferentiated plains material, although in some areas differences can be discerned in the near infrared which might be related to differences in ice grain size. Chaos material is composed of plains and other preexisting materials that have been severely disrupted by inferred internal activity; chaos is characterized by blocks of icy material set in a hummocky matrix. Band material is arrayed in linear, curvilinear, wedge-shaped, or cuspate zones with contrasting albedo and surface textures with respect to the surrounding terrain. Bilateral symmetry observed in some bands and the relationships with the surrounding units suggest that band material forms by the lithosphere fracturing, spreading apart, and infilling with material derived from the subsurface. Ridge material is mapped as a unit on local and some regional maps but shown with symbols at global scales. Ridge material includes single ridges, doublet ridges, and ridge complexes. Ridge materials are considered to represent tectonic processes, possibly accompanied by the extrusion or intrusion of subsurface materials, such as diapirs. The tectonic processes might be related to tidal flexing of the icy lithosphere on diurnal or longer timescales. Crater materials include various interior (smooth central, rough inner, and annular massif) and exterior (continuous ejecta) subunits. Structural features and landforms are shown with conventional symbols. Type localities for the units are identified, along with suggestions for portraying the features on geological maps, including colors and letter abbreviations for material units. Implementing these suggestions by the planetary mapping community would facilitate comparisons of maps for different parts of Europa and contribute to an eventual global synthesis of its complex geology. On the basis of initial mapping results, a stratigraphic sequence is suggested in which ridged plains form the oldest unit on Europa, followed by development of band material and individual ridges. Band materials tend to be somewhat older than ridges, but in many areas the two units formed simultaneously. Similarly, the formation of most chaos follows the development of ridged plains; although chaos is among the youngest materials on Europa, some chaos units might have formed contemporaneously with ridged plains. Smooth plains generally embay all other units and are late-stage in the evolution of the surface. C1 craters are superposed on ridged plains but are crosscut by other materials, including bands and ridges. Most c2 craters postdate all other units, but a few c2 craters are cut by ridge material. C3 craters constitute the youngest recognizable material on Europa. Copyright 2000 by the American Geophysical Union.

Greeley, R.; Figueredo, P. H.; Williams, D. A.; Chuang, F. C.; Klemaszewski, J. E.; Kadel, S. D.; Prockter, L. M.; Pappalardo, R. T.; Head, III, J. W.; Collins, G. C.; Spaun, N. A.; Sullivan, R. J.; Moore, J. M.; Senske, D. A.; Tufts, B. R.; Johnson, T. V.; Belton, M. J. S.; Tanaka, K. L.

2000-01-01

394

Geoscience\\/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico-stratigraphic hierarchy and cycle stacking facies distribution, and interwell-scale heterogeneity: Grayburg Formation, New Mexico. Final report  

Microsoft Academic Search

The Grayburg Formation (middle Guadalupian) is a major producing interval in the Permian Basin and has yielded more than 2.5 billion barrels of oil in West Texas. Grayburg reservoirs have produced, on average, less than 30 percent of their original oil in place and are undergoing secondary and tertiary recovery. Efficient design of such enhanced recovery programs dictates improved geological

R. J. Barnaby; W. B. Ward; J. W. Jr. Jennings

1997-01-01

395

SEISMIC DETERMINATION OF RESERVOIR HETEROGENEITY; APPLICATION TO THE CHARACTERIZATION OF HEAVY OIL RESERVOIRS  

SciTech Connect

The objective of the project is to examine how seismic and geologic data can be used to improve characterization of small-scale heterogeneity and their parameterization in reservoir models. The study is performed at West Coalinga Field in California. We continued our investigation on the nature of seismic reactions from heterogeneous reservoirs. We began testing our algorithm to infer parameters of object-based reservoir models from seismic data. We began integration of seismic and geologic data to determine the deterministic limits of conventional seismic data interpretation. Lastly, we began integration of seismic and geologic heterogeneity using stochastic models conditioned both on wireline and seismic data.

Matthias G. Imhof; James W. Castle

2003-11-01

396

Louisiana Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Louisiana Geological Survey (LGS). The site includes general information about LGS and its various offices, as well as an overview of the Basin Research Energy Section, the oil, gas, and coal research section of LGS. The publications and data page features a catalog and ordering information for documents on mineral resources, fossils, water resources, geological bulletins and maps, and many others, as well as a selection of downloadable maps, including 30 x 60 minute geologic quadrangles, a generalized geologic map of the state with accompanying text, and an online map viewer of the state with selectable layers (geology, water bodies, cultural features, and Landsat imagery). There is also an online listing of well logs, grouped by parish, online listings of core samples, grouped by state, and downloadable public information documents on a variety of geologic topics.

397

Geologic Time: Online Edition  

NSDL National Science Digital Library

Offered by the United States Geological Survey (USGS) as a general interest publication, this site is an online edition of a text by the same name, offering a concise overview of the concepts associated with the age of the Earth. The online edition was revised in October of 1997 to reflect current thinking on this topic. Section headers are Geologic Time, Relative Time Scale, Major Divisions of Geologic Time, Index Fossils, Radiometric Time Scale, and Age of the Earth.

1997-10-09

398

Image Gallery for Geology  

NSDL National Science Digital Library

These images of geologic phenomena are used to supplement introductory geology classes at the University of North Carolina at Chapel Hill. The images are categorized under plutonic, volcanic and sedimentary rocks; structural geology; weathering; and coastlines. There are photographs of different kinds of volcanoes; lavas and pyroclastic rocks; volcanic hazards; different types of sedimentary rocks and sedimentary structures; folds and faults; beach processes; and barrier islands.

Glazner, Allen

399

Sedimentology and petroleum geology  

SciTech Connect

This book presents an introduction to sedimentology as well as petroleum geology. It integrates both subjects, which are closely related but mostly treated separately. The author covers the basic aspects of sedimentology, sedimentary geochemistry and diagenesis. Principles of stratigraphy, seismic stratigraphy and basin modelling forms the base for the part on petroleum geology. Subjects discussed include the composition of kerogen and hydrocarbons, theories of migration and trapping of hydrocarbons and properties of reservoir rocks. Introductions to well logging and production geology are given.

Bjorlykke, K.O. (Oslo Univ. (Norway))

1989-01-01

400

Pennsylvania Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Pennsylvania Geological Survey. Users can access digital maps, data, and Geographic Information Systems (GIS), information on economic resources, and information on field mapping in the state. Classroom resources include a set of lesson plans on Pennsylvania geology; 'Rock Boxes', a set of rock samples which can be ordered; information on mineral collecting; and a series of educational publications, page-sized maps, and the 'Trail of Geology' park guide.

2011-03-29

401

The Geology of Virginia  

NSDL National Science Digital Library

From the College of William of Mary Department of Geology comes the Geology of Virginia Web site. From the Appalachian Plateau to the coastal plain, visitors can explore the geology and physical characteristics of the diverse landscape of the commonwealth of Virginia through simple descriptions and well designed graphics. Even if you don't live in the area, the site does a good job of capturing the interest of anyone looking for quality material on the presented subjects.

1997-01-01

402

Practical petroleum geology  

SciTech Connect

This book contains the following eight chapters: Basic Concepts of Geology; Sedimentation; Oil and Gas Accumulation; Exploration; Economics; Well Sitting; Field Development; and Past, Present and Future. The goal of the book is to present a description of the field of petroleum geology that is centered on the point of view of the practicing petroleum geologist. After the beginning three chapters of pure geology, slanted toward the petroleum geologist's interest in oil and gas, the discussion turns toward more active concerns.

Leecraft, J.

1985-01-01

403

Icelandic Geology Resources  

NSDL National Science Digital Library

The main feature of this site from Hamrahlio College of Reykjavik, Iceland is an interactive geological map of Iceland showing lava flows and glaciers. Other highlights include links to related Icelandic geology pages (e.g., The Effect of Diatom Mining, Iceland's Ministry of the Environment), news sources and journals, and Icelandic geological societies (not all are in English). A recommended resource for glaciologists, volcanologists, and educators in earth science.

Douglas, Georg R.

404

Experimental determination of the solubility constant for magnesium chloride hydroxide hydrate (Mg 3Cl(OH) 5·4H 2O, phase 5) at room temperature, and its importance to nuclear waste isolation in geological repositories in salt formations  

NASA Astrophysics Data System (ADS)

In this study, the solubility constant of magnesium chloride hydroxide hydrate, Mg 3Cl(OH) 5·4H 2O, termed as phase 5, is determined from a series of solubility experiments in MgCl 2-NaCl solutions. The solubility constant in logarithmic units at 25 °C for the following reaction, MgCl(OH)·4HO+5H=3Mg+9HO(l)+Cl is calculated as 43.21 ± 0.33 (2 ?) based on the specific interaction theory (SIT) model for extrapolation to infinite dilution. The Gibbs free energy and enthalpy of formation for phase 5 at 25 °C are derived as -3384 ± 2 (2 ?) kJ mol -1 and -3896 ± 6 (2 ?) kJ mol -1, respectively. MgO (bulk, pure MgO corresponding to the mineral periclase) is the only engineered barrier certified by the Environmental Protection Agency (EPA) for emplacement in the Waste Isolation Pilot Plant (WIPP) in the US, and an Mg(OH) 2-based engineered barrier (bulk, pure Mg(OH) 2 corresponding to brucite) is to be employed in the Asse repository in Germany. Phase 5, and its similar phase, phase 3 (Mg 2Cl(OH) 3·4H 2O), could have a significant role in influencing the geochemical conditions in geological repositories for nuclear waste in salt formations where MgO or brucite is employed as engineered barriers. Based on our solubility constant for phase 5 in combination with the literature value for phase 3, we predict that the composition for the invariant point of phase 5 and phase 3 would be mMg = 1.70 and pmH = 8.94 in the Mg-Cl binary system. The recent WIPP Compliance Recertification Application Performance Assessment Baseline Calculations indicate that phase 5, instead of phase 3, is indeed a stable phase when the WIPP Generic Weep Brine (GWB), a Na-Mg-Cl-dominated brine associated with the Salado Formation, equilibrates with actinide-source-term phases, brucite, magnesium carbonates, halite and anhydrite. Therefore, phase 5 is important to the WIPP, and potentially important to other repositories in salt formations.

Xiong, Yongliang; Deng, Haoran; Nemer, Martin; Johnsen, Shelly

2010-08-01

405

Heterogeneous Soil Morphology on the Taoyuan Terrace, Northwestern Taiwan  

NASA Astrophysics Data System (ADS)

In this study ­soil geomorphology­" is selected to work on the reciprocal relationship between the landscape evolution and soil genesis. Among geological studies on the Taoyuan area, it has remained a concern to apply lateritisation as an index on terrace correlation. To answer this question, the basic knowledge of laterite formation must be clearly understood. On the other hand, pedologists have long been interested in the genesis of laterite, especially those thick ones on the higher terraces. To give insights pedosequences must be built up to distinguish the influence of specific factor. Without assistance of geological data, this goal is hardly achieved. In spite of the obvious demand of interdisciplinary integration, it is short of dialogue between geology and pedology in Taiwan until the last decade when the first soil chronosequence was established in this area. However, the tacit assumption that soils on one geomorphic surface were homogeneous has never been carefully examined. A later study on soil toposequence in the coastal area of Taoyuan terraces soon discovered that soils on one surface were heterogeneous both morphologically and chemically. This finding was explained as the influence of the seasonal undulation of groundwater table. To understand whether the upland soils on geomorphic surfaces are also heterogeneously developed, the soil morphology on the Taoyuan Terrace is selected as target being carefully studied. The relationships among the soil morphology, the undulation of groundwater table (GWT), and the processes of soil formation are established by field investigation and previously reported datasets. Based on recompilation of the published soil maps, the soil series in study area can be divided into eight groups. To compare the soil morphology and assess the reliability of the soil maps, fifteen hand cores are drilled in the field. The datasets of engineering boreholes are also collected to assist the explanation on the spatial variation of soil morphology. We discovered that the soil morphology systematically changes from the terrace edge to the interior, showing a toposequence of red soil, orange soil, yellow soil, mottled soil, and gley soil. Based on the profile reconstructed by the engineering borehole data, the GWT is inconsistent with the subsurface lithology but controlled by the terrace geomorphology. Since soils on the terrace edge are usually developed in well-drained condition for lateritisation, we consequently suggest that they are the best prospective soils for terrace correlation.

Lin, Y.; Chen, Y.; Chen, Z.; Hsieh, M.

2003-12-01

406

Geological evolution and analysis of confirmed or suspected gas hydrate localities: Volume 10, Basin analysis, formation and stability of gas hydrates of the Aleutian Trench and the Bering Sea  

SciTech Connect

Four major areas with inferred gas hydrates are the subject of this study. Two of these areas, the Navarin and the Norton Basins, are located within the Bering Sea shelf, whereas the remaining areas of the Atka Basin in the central Aleutian Trench system and the eastern Aleutian Trench represent a huge region of the Aleutian Trench-Arc system. All four areas are geologically diverse and complex. Particularly the structural features of the accretionary wedge north of the Aleutian Trench still remain the subjects of scientific debates. Prior to this study, suggested presence of the gas hydrates in the four areas was based on seismic evidence, i.e., presence of bottom simulating reflectors (BSRs). Although the disclosure of the BSRs is often difficult, particularly under the structural conditions of the Navarin and Norton basins, it can be concluded that the identified BSRs are mostly represented by relatively weak and discontinuous reflectors. Under thermal and pressure conditions favorable for gas hydrate formation, the relative scarcity of the BSRs can be attributed to insufficient gas supply to the potential gas hydrate zone. Hydrocarbon gas in sediment may have biogenic, thermogenic or mixed origin. In the four studied areas, basin analysis revealed limited biogenic hydrocarbon generation. The migration of the thermogenically derived gases is probably diminished considerably due to the widespread diagenetic processes in diatomaceous strata. The latter processes resulted in the formation of the diagenetic horizons. The identified gas hydrate-related BSRs seem to be located in the areas of increased biogenic methanogenesis and faults acting as the pathways for thermogenic hydrocarbons.

Krason, J.; Ciesnik, M.

1987-01-01

407

Andrei borisovich vistelius: a dominant figure in 20th century mathematical geology  

USGS Publications Warehouse

Andrei Borisovich Vistelius (1915-1995), along with William Christian Krumbein (1902-1979) and John Cedric Griffiths (1912-1992), were dominant figures in the formative and development years of mathematical (or quantitative) geology as a subdiscipline of geology.

Merriam, D. F.

2001-01-01

408

Arizona Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Arizona Geological Survey. Information accessible here includes maps, information on oil, gas, and minerals in the state, back issues of the survey's newsletter, and a list of resources for public education in the state. These resources include information centers for Arizona geology and Earth Science, the survey's geology library and bibliographic database, a repository of rock cuttings and cores, and a contact for earth science education who will assist teacher groups in introducing local geology to their classes.

409

Understanding Geologic Maps  

NSDL National Science Digital Library

This is an exercise in which students are reintroduced to geologic maps and encouraged to "deconstruct" the map into constituent elements in order to understand the geologic history of the area. The preceding lectures in the course have recapitulated material that the students have covered in Introduction to Physical Geology. During class, the students work through the maps that were part of lab exercises in the Intro level course, so that basic concepts are recalled (superposition, cross-cutting relationships, basic faults and folds). The final product is a geologic history of this map area.

Burberry, Cara

410

Geologic Mapping Exercise  

NSDL National Science Digital Library

This exercise is designed to simulate how a basic geological investigation of a site takes place. A basic geological investigation includes familiarizing yourself with the unconsolidated sediments, rocks, structural geology, and groundwater present at your site. As part of this exercise you will have to properly identify a variety of rock types and sediments, create maps that represent data you collected at each location, and complete a basic report of your findings (optional). Once completed, this exercise should give students a basic understanding of how the various concepts used throughout the semester are applied in the real world in the form of a geological investigation.

Smith, Andrew

411