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1

Impact process: an important geological phenomenon.  

PubMed

The impact process was for a long period of time, even after a wider acceptance among the geological community, considered to be a marginal phenomenon in the Earth sciences. The first decade or two have showed an importance of the process itself and consequent events only too clearly. The present paper is a review describing the history and development of the impact hypothesis, structure and origin of impact craters, influence of huge impacts on the living environment and other aspects of the impact process from the point of view of geology s.l. PMID:11541230

Skala, R

1996-01-01

2

Seafloor Eruptions Offer a Teachable Moment to Help SEAS Students Understand Important Geological and Ecological Processes  

NASA Astrophysics Data System (ADS)

In education parlance, a teachable moment is an opportunity that arises when students are engaged and primed to learn, typically in response to some memorable event. Earthquakes, volcanic eruptions, even natural disasters, if meaningful to the student, often serve to catalyze intense learning. Recent eruptions at the East Pacific Rise offer a potential teachable moment for students and teachers involved with SEAS, a Ridge 2000 education outreach program. SEAS uses a combination of web-facilitated and teacher-directed activities to make the remote deep-sea environment and the process of science relevant and meaningful. SEAS is a web-based, inquiry-oriented education program for middle and high school students. It features the science associated with Ridge 2000 research. Since 2003, SEAS has focused on the integrated study site at the East Pacific Rise (EPR) to help students understand geological and ecological processes at mid-ocean ridges and hydrothermal vents. SEAS students study EPR bathymetry maps, images of lava formations, photomosaics of diffuse flow communities, succession in the Bio-Geo Transect, as well as current research conducted during spring cruises. In the Classroom to Sea Lab, students make direct comparisons between shallow-water mussels and vent mussels (from the EPR) to understand differences in feeding strategies. The recent eruptions and loss of seafloor fauna at this site offer the Ridge 2000 program the opportunity to help students better understand the ephemeral and episodic nature of ridge environments, as well as the realities and processes of science (particularly field science). In January 2007, the SEAS program will again sail with a Ridge 2000 research team, and will work with scientists to report findings through the SEAS website. The eruptions at the EPR covered much of the study site, and scientists' instruments and experiments, in fresh lava. We intend to highlight the recency and effect of the eruptions, using the students' anticipated response as a motivator to deepen their understanding of the environment. SEAS depends on the contributions of many scientists within the Ridge 2000 community, and serves as an outreach channel for the whole community. Scientists can help field student questions during the Ask-a- Scientist email forum, serve as Report Reviewers, be featured in Scientist Spotlights, and help develop new Classroom to Sea labs and curricular materials. In the next four years, SEAS will integrate with the international GLOBE education program (www.globe.gov), and help our community reach even more students and teachers, worldwide.

Goehring, L.; Williams, C. S.

2006-12-01

3

Field Geology/Processes  

NASA Technical Reports Server (NTRS)

The field geology/process group examined the basic operations of a terrestrial field geologist and the manner in which these operations could be transferred to a planetary lander. Four basic requirements for robotic field geology were determined: geologic content; surface vision; mobility; and manipulation. Geologic content requires a combination of orbital and descent imaging. Surface vision requirements include range, resolution, stereo, and multispectral imaging. The minimum mobility for useful field geology depends on the scale of orbital imagery. Manipulation requirements include exposing unweathered surfaces, screening samples, and bringing samples in contact with analytical instruments. To support these requirements, several advanced capabilities for future development are recommended. Capabilities include near-infrared reflectance spectroscopy, hyper-spectral imaging, multispectral microscopy, artificial intelligence in support of imaging, x ray diffraction, x ray fluorescence, and rock chipping.

Allen, Carlton; Jakes, Petr; Jaumann, Ralf; Marshall, John; Moses, Stewart; Ryder, Graham; Saunders, Stephen; Singer, Robert

1996-01-01

4

Important geological properties of unconventional resource shales  

NASA Astrophysics Data System (ADS)

The revelation of vast global quantities of potentially productive gas and oil-prone shales has led to advancements in understanding important geological properties which impact reservoir performance. Based upon research on a variety of shales, several geological properties have been recognized as being common and important to hydrocarbon production. (1) transport/depositional processes include hemipelagic `rain', hyperpycnal flows, turbidity current flows, tempestites, wave-reworking, and contour currents in both shallow and deep water settings. (2) Common shale minerals include clays, quartz, calcite, dolomite, apatite, and pyrite; organic constituents include spores ( Tasmanites), plant remains, biogenic quartz and calcite, and arenaceous foraminifera. (3) Porosity and permeability are characteristically low with pore sizes ranging down to the nanoscale. Main pore types include intergranular (including pores within clay floccules), porous organic matter, porous fecal pellets, and microfractures. (4) Important geochemical characteristics include organic richness (>3%), maturity (>1.1%Ro for shale gas and 0.6-0.9% for shale oil) and type (I-IV), in addition to certain biomarkers which are indicators of bottom water oxicity during deposition. Remaining hydrocarbon potential [RHP = (S1 + S2)/TOC] also reflects temporal environmental changes. `Isotopic reversals' can be used to detect best producing areas in shale-gas plays. (5) Lithofacies stacking patterns and sequence stratigraphy are the result of eustatic depositional history. A general sequence stratigraphic model is presented here that highlights this commonality. (6) Geomechanical properties are key to drilling, fracturing and production of hydrocarbons. Brittle-ductile couplets at several scales occur in shale sequences. (7) Geophysical properties, when calibrated to rock properties, provide a means of regionally to locally mapping the aforementioned properties. (8) Economic and societal considerations in the exploration and development of resource shales are garnering attention. Many potentially economic shale-gas and shale-oil plays are being identified globally. Risks and uncertainties associated with gas- and oil-rich shales include the lack of long-term production histories, environmental concerns related to hydraulic fracturing, uncertainty in calculating hydrocarbons-in-place, and fluctuations in supply, demand, and price.

Slatt, Roger M.

2011-12-01

5

Oceanography - Marine Geological Processes  

NSDL National Science Digital Library

A first year course in oceanography with extensive Internet resources. Topics covered include: principles of thermodynamics, heat and mass transfer, fluid mechanics, continuum mechanics, and time-series analysis applied to marine geological and geophysical data; applications to transport of marine sediments; Pleistocene sedimentation and global climate change; and the thermal balance of the oceanic lithosphere. The link to the lecture schedule provides detailed supporting materials.

Mcduff, Russell

6

Coastal Geological Processes  

NSDL National Science Digital Library

Coastlines are places of continuous, often dramatic geological activity. They change daily and seasonally, but especially over long time periods. This interactive feature discusses the forces that help shape coastal landforms like cliffs and beaches. Topics include waves, tides, and currents; weathering, erosion, and deposition; and other factors, such as the activity of organisms and human modifications. A background essay and discussion questions are included.

2011-02-03

7

Coastal Geological Processes  

NSDL National Science Digital Library

Coastlines are places of continuous, often dramatic geological activity. They change daily and seasonally, but especially over long time periods. This interactive feature discusses the forces that help shape coastal landforms like cliffs and beaches. Topics include waves, tides, and currents; weathering, erosion, and deposition; and other factors, such as the activity of organisms and human modifications. A background essay and discussion questions are included.

8

Computer image processing: Geologic applications  

NASA Technical Reports Server (NTRS)

Computer image processing of digital data was performed to support several geological studies. The specific goals were to: (1) relate the mineral content to the spectral reflectance of certain geologic materials, (2) determine the influence of environmental factors, such as atmosphere and vegetation, and (3) improve image processing techniques. For detection of spectral differences related to mineralogy, the technique of band ratioing was found to be the most useful. The influence of atmospheric scattering and methods to correct for the scattering were also studied. Two techniques were used to correct for atmospheric effects: (1) dark object subtraction, (2) normalization of use of ground spectral measurements. Of the two, the first technique proved to be the most successful for removing the effects of atmospheric scattering. A digital mosaic was produced from two side-lapping LANDSAT frames. The advantages were that the same enhancement algorithm can be applied to both frames, and there is no seam where the two images are joined.

Abrams, M. J.

1978-01-01

9

Quantifying the Spatial Distribution of Geological Point Processes  

NASA Astrophysics Data System (ADS)

Geological point processes occur frequently in a wide variety of geoscience fields, including the study of mineral deposits, oil producing wells, earthquakes, and landsides. Characterization of the spatial distribution of geological point processes is important for understanding the properties of geological processes or events. Three examples of geological point processes respectively dealing with metallic mineral deposits, oil producing wells and Wenchuan aftershocks were studied. It is demonstrated that (1) the L(r), G(r), F(r) and J(r) functions are useful tools to assess whether or not a point pattern shows spatial clustering; (2) the clustering statistics of the underlying geological process are farctal; (3) a higher intensity point pattern generally has relatively large box dimension and low lacunarity; and (4) the features of geological point processes, such as metal grade, total amount or magnitude also have fractal properties.

Zuo, R.; Cheng, Q.

2009-04-01

10

Health benefits of geologic materials and geologic processes  

USGS Publications Warehouse

The reemerging field of Medical Geology is concerned with the impacts of geologic materials and geologic processes on animal and human health. Most medical geology research has been focused on health problems caused by excess or deficiency of trace elements, exposure to ambient dust, and on other geologically related health problems or health problems for which geoscience tools, techniques, or databases could be applied. Little, if any, attention has been focused on the beneficial health effects of rocks, minerals, and geologic processes. These beneficial effects may have been recognized as long as two million years ago and include emotional, mental, and physical health benefits. Some of the earliest known medicines were derived from rocks and minerals. For thousands of years various clays have been used as an antidote for poisons. "Terra sigillata," still in use today, may have been the first patented medicine. Many trace elements, rocks, and minerals are used today in a wide variety of pharmaceuticals and health care products. There is also a segment of society that believes in the curative and preventative properties of crystals (talismans and amulets). Metals and trace elements are being used in some of today's most sophisticated medical applications. Other recent examples of beneficial effects of geologic materials and processes include epidemiological studies in Japan that have identified a wide range of health problems (such as muscle and joint pain, hemorrhoids, burns, gout, etc.) that may be treated by one or more of nine chemically distinct types of hot springs, and a study in China indicating that residential coal combustion may be mobilizing sufficient iodine to prevent iodine deficiency disease. ?? 2006 MDPI. All rights reserved.

Finkelman, R.B.

2006-01-01

11

Comparison Charts of Geological Processes: Terrestrial Planets  

NSDL National Science Digital Library

This chart presents information on the geological processes (volcanism, impact cratering, tectonics, and gradation) that have affected the Earth, Moon, and the terrestrial planets. Students compare the effects these processes have had on the Moon and planets. There is also a blank chart and a sheet of notes on the geological processes that may be used in conjunction with this chart. This chart is one of the activities for the Exploring Planets in the Classroom's Introduction to the Solar System.

12

Computer simulation of geological processes  

NASA Astrophysics Data System (ADS)

To realistically simulate subsurface processes such as fluid flow, three dimensional models are needed. The physical processes involved in these models are specified by differential equations coupled by pressure- and temperature-dependent physical properties. Finite element numerical methods are used here to solve the equations. This thesis illustrates some of these methods. The equations that are used in these models are all derived and explained. Also, the definition and sample values of all the basic physical properties are provided in introductory chapters. Oil is generated in sedimentary basins when the temperature is within a certain range. Hence only specific regions within a sedimentary basin are capable of generating oil. If oil is generated, it needs to find pathways to shallower reservoirs where commercially significant quantities can accumulate. This migration procedure is normally a vertical process but can, depending on the permeability conditions, move hundreds of kilometers horizontally. Hot magma intrusions cause seawater to convect below the seafloor. This convective motion can generate mineral deposits. To understand where these deposits will form and how large they can be, 3D convection models are used to simulate the mineral deposition process. The results are given in the form of maps of the numerically simulated deposits on the seafloor. Fluids in sedimentary basins generally consist of several phases, such as water gas and oil. The existence of more than one phase can affect how fluids flow in reservoirs and inhibit production. The temperature and pressure conditions are other factors that determine what fraction of a hydrocarbon mixture is in a gas phases or in a liquid phase. The calculations for phase behavior of fluids and reservoir simulation calculations are carried out in the last two chapters.

Erendi, Alex

2000-11-01

13

Acoustic fluidization - A new geologic process  

NASA Technical Reports Server (NTRS)

A number of geologic processes, particularly seismic faulting, impact crater slumping, and long runout landslides, require the failure of geologic materials under differential stresses much smaller than expected on the basis of conventional rock mechanics. This paper proposes that the low strengths apparent in these phenomena are due to a state of 'acoustic fluidization' induced by a transient strong acoustic wave field. The strain rates possible in such a field are evaluated, and it is shown that acoustically fluidized debris behaves as a newtonian fluid with a viscosity in the range 100,000 to 10,000,000 P for plausible conditions. Energy gains and losses in the acoustic field are discussed, and the mechanism is shown to be effective if internal dissipation in the field gives a Q approximately greater than 100. Whether such values for Q are realized is not known at present. However, acoustic fluidization provides a qualitatively correct description of the failure of rock debris under low differential stresses in the processes of faulting, crater slumping, and long runout landslides. Acoustic fluidization thus deserves serious consideration as a possible explanation of these phenomena.

Melosh, H. J.

1979-01-01

14

Importance of process oriented organizations  

NASA Astrophysics Data System (ADS)

This paper analyzes different types of start-up aerospace organizations, common mistakes and the importance of process oriented management systems. It is made using experience in starting up 5 airlines, one microlight aircraft production, two GLXP teams and 4 space technology companies' startup.

Bedic, S.

2013-09-01

15

Planetary geology: Impact processes on asteroids  

NASA Technical Reports Server (NTRS)

The fundamental geological and geophysical properties of asteroids were studied by theoretical and simulation studies of their collisional evolution. Numerical simulations incorporating realistic physical models were developed to study the collisional evolution of hypothetical asteroid populations over the age of the solar system. Ideas and models are constrained by the observed distributions of sizes, shapes, and spin rates in the asteroid belt, by properties of Hirayama families, and by experimental studies of cratering and collisional phenomena. It is suggested that many asteroids are gravitationally-bound "rubble piles.' Those that rotate rapidly may have nonspherical quasi-equilibrium shapes, such as ellipsoids or binaries. Through comparison of models with astronomical data, physical properties of these asteroids (including bulk density) are determined, and physical processes that have operated in the solar system in primordial and subsequent epochs are studied.

Chapman, C. R.; Davis, D. R.; Greenberg, R.; Weidenschilling, S. J.

1982-01-01

16

Significant achievements in the Planetary Geology Program. [geologic processes, comparative planetology, and solar system evolution  

NASA Technical Reports Server (NTRS)

Developments reported at a meeting of principal investigators for NASA's planetology geology program are summarized. Topics covered include: constraints on solar system formation; asteriods, comets, and satellites; constraints on planetary interiors; volatiles and regoliths; instrument development techniques; planetary cartography; geological and geochemical constraints on planetary evolution; fluvial processes and channel formation; volcanic processes; Eolian processes; radar studies of planetary surfaces; cratering as a process, landform, and dating method; and the Tharsis region of Mars. Activities at a planetary geology field conference on Eolian processes are reported and techniques recommended for the presentation and analysis of crater size-frequency data are included.

Head, J. W. (editor)

1978-01-01

17

Geologic processes on Venus: An update  

NASA Technical Reports Server (NTRS)

Studies of Venera 15 and 16 radar image and altimetry data and reevaluation of Pioneer Venus and earlier Venera data have greatly expanded the perception of the variety and complexity of geologic processes on Venus. PV data have discriminated four highland regions (each different in geomorphic appearance), a large upland rolling plains region, and smaller areas of lowland plains. Two highland volcanic centers were identified that may be presently active, as suggested by their geomorphologic appearance combined with positive gravity anomalies, lightning strike clusters, and a change in SO2 content in the upper atmosphere. Geochemical data obtained by the Venera landers have indicated that one upland area and nearby rolling plains are composed of volcanic rocks, probably basalts or syenites. New Venera radar images of the Ishtar Terra region show folded and/or faulted linear terrain and associated volcanic features that may have been deformed by both compressional and extensional forces. Lowland surfaces resemble the mare basaltic lava flows that fill basins on the Moon, Mars and Earth. Ubiquitous crater like forms may be of either volcanic or impact origin; the origin of similar lunar features was determined by the character of their ejecta deposits.

Masursky, H.

1985-01-01

18

Will Somebody do the Dishes? Weathering Analogies, Geologic Processes and Geologic Time  

NASA Astrophysics Data System (ADS)

A good analogy is one of the most powerful tools in any instructors' arsenal, and encouraging students to explore the links between an analogy and a scientific concept can cement both ideas in a student's mind. A common analogy for weathering and erosion processes is doing the dishes. Oxidation, hydration, and solution reactions can be intimidating on the chalkboard but easily understood in the context of cleaning up after dinner. Rather than present this analogy as a lecture demonstration, students are encouraged to experimentally determine which type of weathering works best on their dirty dishes. The experiment must use at least four identically dirty dishes: three experimental dishes and one control dish. The experimental dishes are subjected to simulated weathering and erosion processes of the student's design. Common techniques developed by students are cold or warm water baths, baths with and without acid (lemon juice or soda), and freeze-thaw cycles. Occasionally creative experiments result in unexpected discoveries, such the inefficiency of abrasion from wind-blown sand, especially when compared to soaking dishes in Canadian Whiskey. The effectiveness of each experimental run is determined by comparison to the control plate after loose debris is removed from each. The dish with the smallest aerial extent of remaining food is the declared the most effective. Discussion sections of the experimental write-up includes a description of which geologic processes were being simulated in each experiment, comparisons of the effectiveness of each techniques, and statements of how these experiments differ from reality. In order to advance this project, a second stage of the assignment, a direct comparison of weathering and erosion techniques on food and on geologic materials, will be added this fall. Ideally, students will empirically derive erosion rates and calculate the time required to remove the volume of material represented by a geologically important feature, such as Mt. Rainier or the Grand Canyon. In the end, students completing this project gain an understanding of how geologic processes work, the time scales required, the differences between analogies and the real thing, and arguably the most important aspect, a best-practices approach to doing the dishes.

Stelling, P.; Wuotila, S.; Giuliani, M.

2006-12-01

19

The Moon: Keystone to Understanding Planetary Geological Processes and History  

NASA Technical Reports Server (NTRS)

Extensive and intensive exploration of the Earth's Moon by astronauts and an international array of automated spacecraft has provided an unequaled data set that has provided deep insight into geology, geochemistry, mineralogy, petrology, chronology, geophysics and internal structure. This level of insight is unequaled except for Earth. Analysis of these data sets over the last 35 years has proven fundamental to understanding planetary surface processes and evolution, and is essential to linking surface processes with internal and thermal evolution. Much of the understanding that we presently have of other terrestrial planets and outer planet satellites derives from the foundation of these data. On the basis of these data, the Moon is a laboratory for understanding of planetary processes and a keystone for providing evolutionary perspective. Important comparative planetology issues being addressed by lunar studies include impact cratering, magmatic activity and tectonism. Future planetary exploration plans should keep in mind the importance of further lunar exploration in continuing to build solid underpinnings in this keystone to planetary evolution. Examples of these insights and applications to other planets are cited.

2002-01-01

20

Venus and the Earth's Archean: Geological mapping and process comparisons  

NASA Astrophysics Data System (ADS)

Introduction. The geological features, structures, thermal conditions, interpreted processes, and outstanding questions related to both the Earth's Archean and Venus share many similarities [1-3] and we are using a problem-oriented approach to Venus mapping, guided by insight from the Archean record of the Earth, to gain new perspectives on the evolution of Venus and Earth's Archean. The Earth's preserved and well-documented Archean record [4] provides important insight into high heat-flux tectonic and magmatic environments and structures [5] and the surface of Venus reveals the current configuration and recent geological record of analogous high-temperature environments unmodified by subsequent several billion years of segmentation and overprinting, as on Earth. Here we address the nature of the Earth's Archean, the similarities to and differences from Venus, and the specific Venus and Earth-Archean problems on which progress might be made through comparison. The Earth's Archean and its Relation to Venus. The Archean period of Earth's history extends from accretion/initial crust formation (sometimes called the Hadean) to 2.5 Ga and is thought of by most workers as being a transitional period between the earliest Earth and later periods largely dominated by plate tectonics (Proterozoic and Phanerozoic) [2, 4]. Thus the Archean is viewed as recording a critical period in Earth's history in which a transition took place from the types of primary and early secondary crusts seen on the Moon, Mars and Mercury [6] (and largely missing in the record of the Earth), to the style of crustal accretion and plate tectonics characterizing later Earth history. The Archean is also characterized by enhanced crustal and mantle temperatures leading to differences in deformation style and volcanism (e.g., komatiites) [2]. The preserved Archean crust is exposed in ~36 different cratons [4], forming the cores of most continental regions, and is composed of gneisses, plutons and greenstones. The geological record of the Archean Earth is considerably different than the Phanerozoic record and ongoing processes [1, 7]. The Archean record is characterized by evidence for enhanced mantle temperatures, different styles of crustal deformation (localized belts of high intensity deformation, tight high and low angle folds, diapiric-related deformation, significant lateral differences in lithospheric thickness (implied by 'cold' keels), significant evidence for crustal thickening processes and the burial and exhumation of thickened crust, abundant hightemperature komatiites, greenstone belts, "mafic plains"-type greenstones, positive gneissic and felsic diapirs, abundance of a distinctive TTG (tonalitetrondhjemite- granodiorite) assemblage, layered gabbro- anorthosite igneous intrusions, very abundant plume-derived basalts, unusual events interpreted to represent mantle instability and overturn, late stage granodiorites and granites derived from intracrustal melting, epicratonic basins, and production of large volumes of continental crust [1,4,5]. A major question in the study of the Archean is the nature of the geodynamic processes operating during this time. Do the geodynamic processes represent a steady-state accommodation to the Archean thermal environment, or do they represent a transitional or evolutionary phase? Does the Archean represent a particular unique style of vertical tectonics, as on oneplate planets, lateral tectonics (perhaps early plate tectonics) as on later Earth, or is it transitional in time (and perhaps in space), changing from one style to another during the Archean? What role do the enhanced mantle and crustal temperatures play in volcanism and tectonism during this period? Do global crustal and lithospheric density instabilities play a major role in the transition [8], perhaps causing catastrophic foundering and crustal overturn [9], as thought to have occurred on the Moon and Mars? Does vertical crustal accretion dominate over lateral crustal accretion, leading to density instabilities and planet-wide diapiric upwel

Head, J. W.; Hurwitz, D. M.; Ivanov, M. A.; Basilevsky, A. T.; Senthil Kumar, P.

2008-09-01

21

Geologic input to work processes at Duri Field, Indonesia  

SciTech Connect

Dud Field, central Sumatra, Indonesia, at 300,000 bbls per day from over 3000 wells is considered the world`s largest steamflood. A project of this magnitude presents significant challenges during the planning, implementation, and operational phases. One of the biggest challenges was to increase the amount of geological data being used in decisions made on a daily basis in operations. This paper will focus on the contributions made by geologists to pattern analysis, a key process within the now, cross-functional, Asset Management Teams. The geological contribution to pattern analysis is zone correlation, geostatistical modeling, and establishment of flow units on a pattern basis. The tools necessary for the effort include statistics, formation evaluation, post steam resistivity logs, computer mapping (reserves, kh, Phi-H-So, transmissivity, 4D seismic). All applied on a pattern area to layers (15 acre patterns, 5-8 layers per pattern). The geology products are now integrated with other information, (temperature surveys, krypton surveys, PNC logs, well head temperatures, liner damage image), all previously used with little geology input. Each AMT is responsible for approximately 150-200 patterns and each pattern must be reviewed twice a year. Each work day of the year, up to 24 wells and all new data are reviewed. The pace of work requires dependable, easily communicated analyses. Estimates that this layer management of the steamflood increases the recovery efficiency by 5% at a minimum, a potential increase in reserves of 500 million barrels.

Primadi, H.; Jackson, W.D.; McNaboe, G.J.; Bamahry, L. [and others

1996-12-31

22

Geologic input to work processes at Duri Field, Indonesia  

SciTech Connect

Dud Field, central Sumatra, Indonesia, at 300,000 bbls per day from over 3000 wells is considered the world's largest steamflood. A project of this magnitude presents significant challenges during the planning, implementation, and operational phases. One of the biggest challenges was to increase the amount of geological data being used in decisions made on a daily basis in operations. This paper will focus on the contributions made by geologists to pattern analysis, a key process within the now, cross-functional, Asset Management Teams. The geological contribution to pattern analysis is zone correlation, geostatistical modeling, and establishment of flow units on a pattern basis. The tools necessary for the effort include statistics, formation evaluation, post steam resistivity logs, computer mapping (reserves, kh, Phi-H-So, transmissivity, 4D seismic). All applied on a pattern area to layers (15 acre patterns, 5-8 layers per pattern). The geology products are now integrated with other information, (temperature surveys, krypton surveys, PNC logs, well head temperatures, liner damage image), all previously used with little geology input. Each AMT is responsible for approximately 150-200 patterns and each pattern must be reviewed twice a year. Each work day of the year, up to 24 wells and all new data are reviewed. The pace of work requires dependable, easily communicated analyses. Estimates that this layer management of the steamflood increases the recovery efficiency by 5% at a minimum, a potential increase in reserves of 500 million barrels.

Primadi, H.; Jackson, W.D.; McNaboe, G.J.; Bamahry, L. (and others)

1996-01-01

23

Digitizing rocks: Standardizing the process of geologic description with workstations  

SciTech Connect

In the drive to squeeze the most value from every dollar spent on exploration and development, increasing use is being made of stored data through methods that rely on the completeness and accuracy of the database for their usefulness. Although many types of engineering data are available to the process, geologic data, especially those collected at a sufficiently detailed level to show reservoir heterogeneity, are often unavailable to later workers in any useful form. Traditionally, most wellsite geologic data are recorded on worksheets or notebooks, from which summary data are often transferred to computers. The only changes in recent years have been related to the process by which computer-drafted lithology logs have superseded hand-drawn logs; in some exceptions, some of the plotting data may be held in a simple database. These descriptions and analyses, gathered at considerable cost and capable of showing significant petrological detail, are not available to the whole field-development process. The authors set out to tackle these problems of limited usefulness and development a system that would deliver quality geologic data deep into the field of play in a form that was easy to select and integrated with existing models.

Saunders, M.R.; Shields, J.A.; Taylor, M.R. [Baker Hughes INTEQ, Houston, TX (United States)

1995-06-01

24

Online Courses: Mississippi State University: Geology I: Processes and Products  

NSDL National Science Digital Library

Does your curriculum include concepts in geology? Do you need to continue your education in earth science? Geology I from the Teachers in Geosciences covers the foundational material in physical geology that you need to understand to successfully teach

1900-01-01

25

Processing of multispectral thermal IR data for geologic applications  

NASA Technical Reports Server (NTRS)

Multispectral thermal IR data were acquired with a 24-channel scanner flown in an aircraft over the E. Tintic Utah mining district. These digital image data required extensive computer processing in order to put the information into a format useful for a geologic photointerpreter. Simple enhancement procedures were not sufficient to reveal the total information content because the data were highly correlated in all channels. The data were shown to be dominated by temperature variations across the scene, while the much more subtle spectral variations between the different rock types were of interest. The image processing techniques employed to analyze these data are described.

Kahle, A. B.; Madura, D. P.; Soha, J. M.

1979-01-01

26

Importance of geologic characterization of potential low-level radioactive waste disposal sites  

USGS Publications Warehouse

Using the example of the Geff Alternative Site in Wayne County, Illinois, for the disposal of low-level radioactive waste, this paper demonstrates, from a policy and public opinion perspective, the importance of accurately determining site stratigraphy. Complete and accurate characterization of geologic materials and determination of site stratigraphy at potential low-level waste disposal sites provides the frame-work for subsequent hydrologic and geochemical investigations. Proper geologic characterization is critical to determine the long-term site stability and the extent of interactions of groundwater between the site and its surroundings. Failure to adequately characterize site stratigraphy can lead to the incorrect evaluation of the geology of a site, which in turn may result in a lack of public confidence. A potential problem of lack of public confidence was alleviated as a result of the resolution and proper definition of the Geff Alternative Site stratigraphy. The integrity of the investigation was not questioned and public perception was not compromised. ?? 1991 Springer-Verlag New York Inc.

Weibel, C. P.; Berg, R. C.

1991-01-01

27

Geology  

NSDL National Science Digital Library

With three levels to choose from on each page - beginner, intermediate or advanced - this site provides information on the many different kinds of geological exploration. The elements that make up minerals and the different ways minerals are developed, The special characteristics of minerals, like physical properties, is explained. Earths tectonic plates, the reasons they move, and the effects of the shifting are also given. Also featured is fossils and how they are developed and are found, as well as why fossils are useful tools for scientists.

Bergman, Jennifer

2009-08-03

28

Distribution And Interplay Of Geologic Processes On Titan: Analysis Using Cassini Data  

NASA Astrophysics Data System (ADS)

The major planetary geologic processes - volcanism, tectonism, impact cratering and erosion - have played a role in shaping Titan's complex surface. We use data obtained by Cassini's Titan Radar Mapper, in its Synthetic Aperture Radar (SAR) mode, to analyze the distribution of geologic processes on Titan, both endogenic and exogenic, and to derive temporal relationships between these processes, at least at local scales. We compare SAR data with those from the Imaging Science Subsystem (ISS) and the Visual and Infrared Mapping Spectrometer (VIMS) to look for correlations that can extend our knowledge of both spatial distribution and temporal relationships. Although stratigraphic relationships are hard to establish from the available data, they are sufficiently clear in some places that a picture of Titan's geologic evolution is emerging. Erosional/depositional processes, both from fluvial and aeolian activity, play a major role modifying Titan's surface. Fluvial features are widespread in both latitude and longitude and are seen at many different scales. Lacustrine features are widespread at high northern latitudes and there are suggestions of similar features at high southern latitudes as well. Fluvial erosion may be the dominant modification process at high latitudes, while erosion and burial as a result of aeolian activity may dominate the lower latitudes. In at least one location near the equator, dunes overlay fluvial deposits. Cryovolcanic features are not widespread but show no preference for latitude or longitude given the current data. Tectonic features (mountains and ridges) appear more common at low latitudes and may be compressional in origin, though other features that may be fractures might indicate extension. The impact record on Titan seems to have been mostly obliterated by other processes. The distribution and interplay of geologic processes is important to provide constraints on models of the interior and of surface-atmosphere interactions.

Lopes, Rosaly M.; Stofan, E. R.; Peckyno, R.; Mitri, G.; Mitchell, K. L.; Wood, C. A.; Radebaugh, J.; Kirk, R. L.; Wall, S. D.; Lorenz, R.; Lunine, J. I.; Craig, J.; Turtle, E. P.; Barnes, J. W.; Paganelli, F.; Cassini RADAR Team

2007-10-01

29

76 FR 13207 - Announcement of the U.S. Geological Survey Science Strategy Planning Feedback Process  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF THE INTERIOR U.S. Geological Survey [USGS-GX11AA0000A1300] Announcement of the U.S. Geological Survey Science Strategy Planning Feedback Process AGENCY: U.S. Geological Survey, Interior. ACTION: Notice of Feedback...

2011-03-10

30

77 FR 34062 - Announcement of the U.S. Geological Survey Science Strategy Planning Feedback Process  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF THE INTERIOR U.S. Geological Survey [USGS-GX11AA0000A1300] Announcement of the U.S. Geological Survey Science Strategy Planning Feedback Process AGENCY: U.S. Geological Survey, Interior. ACTION: Notice of Feedback...

2012-06-08

31

77 FR 43110 - Announcement of the U.S. Geological Survey Science Strategy Planning Feedback Process  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF THE INTERIOR U.S. Geological Survey [USGS-GX11AA0000A1300] Announcement of the U.S. Geological Survey Science Strategy Planning Feedback Process AGENCY: U.S. Geological Survey, Interior. ACTION: Notice of feedback...

2012-07-23

32

Database for volcanic processes and geology of Augustine Volcano, Alaska  

USGS Publications Warehouse

This digital release contains information used to produce the geologic map published as Plate 1 in U.S. Geological Survey Professional Paper 1762 (Waitt and Begét, 2009). The main component of this digital release is a geologic map database prepared using geographic information systems (GIS) applications. This release also contains links to files to view or print the map plate, accompanying measured sections, and main report text from Professional Paper 1762. It should be noted that Augustine Volcano erupted in 2006, after the completion of the geologic mapping shown in Professional Paper 1762 and presented in this database. Information on the 2006 eruption can be found in U.S. Geological Survey Professional Paper 1769. For the most up to date information on the status of Alaska volcanoes, please refer to the U.S. Geological Survey Volcano Hazards Program website.

McIntire, Jacqueline; Ramsey, David W.; Thoms, Evan; Waitt, Richard B.; Beget, James E.

2012-01-01

33

Beowulf Distributed Processing and the United States Geological Survey  

USGS Publications Warehouse

Introduction In recent years, the United States Geological Survey's (USGS) National Mapping Discipline (NMD) has expanded its scientific and research activities. Work is being conducted in areas such as emergency response research, scientific visualization, urban prediction, and other simulation activities. Custom-produced digital data have become essential for these types of activities. High-resolution, remotely sensed datasets are also seeing increased use. Unfortunately, the NMD is also finding that it lacks the resources required to perform some of these activities. Many of these projects require large amounts of computer processing resources. Complex urban-prediction simulations, for example, involve large amounts of processor-intensive calculations on large amounts of input data. This project was undertaken to learn and understand the concepts of distributed processing. Experience was needed in developing these types of applications. The idea was that this type of technology could significantly aid the needs of the NMD scientific and research programs. Porting a numerically intensive application currently being used by an NMD science program to run in a distributed fashion would demonstrate the usefulness of this technology. There are several benefits that this type of technology can bring to the USGS's research programs. Projects can be performed that were previously impossible due to a lack of computing resources. Other projects can be performed on a larger scale than previously possible. For example, distributed processing can enable urban dynamics research to perform simulations on larger areas without making huge sacrifices in resolution. The processing can also be done in a more reasonable amount of time than with traditional single-threaded methods (a scaled version of Chester County, Pennsylvania, took about fifty days to finish its first calibration phase with a single-threaded program). This paper has several goals regarding distributed processing technology. It will describe the benefits of the technology. Real data about a distributed application will be presented as an example of the benefits that this technology can bring to USGS scientific programs. Finally, some of the issues with distributed processing that relate to USGS work will be discussed.

Maddox, Brian G.

2002-01-01

34

Influences of geomorphology and geology on alpine treeline in the American West - More important than climatic influences?  

USGS Publications Warehouse

The spatial distribution and pattern of alpine treeline in the American West reflect the overarching influences of geological history, lithology and structure, and geomorphic processes and landforms, and geologic and geomorphic factors - both forms and processes - can control the spatiotemporal response of the ecotone to climate change. These influences occur at spatial scales ranging from the continental scale to fine scale processes and landforms at the slope scale. Past geomorphic influences, particularly Pleistocene glaciation, have also left their impact on treeline, and treelines across the west are still adjusting to post-Pleistocene conditions within Pleistocene-created landforms. Current tine scale processes include solifluction and changes on relict solifluction and digging by animals. These processes should be examined in detail in future studies to facilitate a better understanding of where individual tree seedlings become established as a primary response of the ecotone to climate change. Copyright ?? 2007 by Bellwether Publishing, Ltd. All rights reserved.

Butler, D.R.; Malanson, G.P.; Walsh, S.J.; Fagre, D.B.

2007-01-01

35

Scaling filtering and multiplicative cascade information integration techniques for geological, geophysical and geochemical data processing and geological feature recognition  

NASA Astrophysics Data System (ADS)

This paper introduces several techniques recently developed based on the concepts of multiplicative cascade processes and multifractals for processing exploration geochemical and geophysical data for recognition of geological features and delineation of target areas for undiscovered mineral deposits. From a nonlinear point of view extreme geo-processes such as cloud formation, rainfall, hurricanes, flooding, landslides, earthquakes, igneous activities, tectonics and mineralization often show singular property that they may result in anomalous amounts of energy release or mass accumulation that generally are confined to narrow intervals in space or time. The end products of these non-linear processes have in common that they can be modeled as fractals or multifractals. Here we show that the three fundamental concepts of scaling in the context of multifractals: singularity, self-similarity and fractal dimension spectrum, make multifractal theory and methods useful for geochemical and geophysical data processing for general purposes of geological features recognition. These methods include: a local singularity analysis based on a area-density (C-A) multifractal model used as a scaling high-pass filtering technique capable of extracting weak signals caused by buried geological features; a suite of multifractal filtering techniques based on spectrum density - area (S-A) multifractal models implemented in various domain including frequency domain can be used for unmixing geochemical or geophysical fields according to distinct generalized self-similarities characterized in certain domain; and multiplicative cascade processes for integration of diverse evidential layers of information for prediction of point events such as location of mineral deposits. It is demonstrated by several case studies involving Fe, Sn, Mo-Ag and Mo-W mineral deposits that singularity method can be utilized to process stream sediment/soil geochemical data and gravity/aeromagnetic data as high-pass filtering technique for delineating anomalies caused by mineralization or boundaries of mineralization-associated geological bodies; S-A method can be applied as high-pass, low-pass or band -pass filtering techniques for extracting patterns of interest from mixing data; and cascade processes can be implemented to integrate diverse layers of information for mineral resources predictive mapping.

Cheng, Q.

2013-12-01

36

Important geological and biological impacts of natural hydrocarbon seeps: Northern Gulf of Mexico continental slope  

SciTech Connect

Large volumes of siliciclastic sediments, input especially during periods of lowered sea level, and compensating salt tectonics have produced a continental slope that is arguably the most complex in today's oceans. Faults associated with deformation of salt and shale provide the primary migration routes for hydrocarbon gases, crude oil, brines, and formation fluids to the modern sea floor. Since the mid 1980s, it has become increasingly clearer that this process has an extremely important impact on the geomorphology, sedimentology, and biology of the modern continental slope. Hydrocarbon source, flux rate, and water depth are important determinants of sea-floor response. Under rapid flux conditions mud volcanoes (to 1 km wide and 50 m high) result, and hydrate hills (rich with authigenic carbonates), carbonate lithoherms, and isolated communities of chemosymbiotic organisms with associated hardgrounds represent much slower flux responses. In numerous moderate- to low-flux cases, cold seep products function to support islands of productivity for communities of chemosymbiotic organisms that contribute both directly (shell material) and through chemical byproducts to the production of massive volumes of calcium-magnesium carbonate in the form of hardgrounds, stacked slabs, and discrete moundlike buildups (commonly >20m). Seep-related carbonates of the Gulf of Mexico continental slope, as well those formed through degassing of accretionary prisms along active margins, are now thought to create hardgrounds and discrete buildups that are excellent analogs for many problematic carbonate buildups in ancient deep-water siliciclastic rocks.

Roberts, H.H. (Louisiana State Univ., Baton Rouge, LA (United States))

1993-11-01

37

Geologic processes and Cenozoic history related to salt dissolution in southeastern New Mexico  

USGS Publications Warehouse

Salt of Permian age in the subsurface of an area near The Divide, east of Carlsbad, N. Mex., is being considered for a nuclear waste repository. The geologic history of the region indicates that dissolution of salt has occurred in the past during at least three distinct epochs: (1) after Triassic but before middle Pleistocene time; (2) during middle Pleistocene; and (3) during late Pleistocene. Thus, destructive geologic processes have been intermittent through more than I00 million years. Nash Draw, near The Divide, formed during late Pleistocene time by the coalescing of collapse sinks. The rate of its subsidence is estimated to have been about 10 cm (0.33 foot) per thousand years. The immediate area of The Divide adjacent to Nash Draw has not undergone stress by geologic processes during Pleistocene time and there are no present indications that this geologic environment will change drastically within the period of concern for the repository.

Bachman, George Odell

1974-01-01

38

Distribution and interplay of geologic processes on Titan from Cassini radar data  

Microsoft Academic Search

The Cassini Titan Radar Mapper is providing an unprecedented view of Titan’s surface geology. Here we use Synthetic Aperture Radar (SAR) image swaths (Ta–T30) obtained from October 2004 to December 2007 to infer the geologic processes that have shaped Titan’s surface. These SAR swaths cover about 20% of the surface, at a spatial resolution ranging from ?350m to ?2km. The

R. M. C. Lopes; E. R. Stofan; R. Peckyno; J. Radebaugh; K. L. Mitchell; G. Mitri; C. A. Wood; R. L. Kirk; S. D. Wall; J. I. Lunine; A. Hayes; R. Lorenz; T. Farr; L. Wye; J. Craig; R. J. Ollerenshaw; M. Janssen; A. Legall; F. Paganelli; B. Stiles; P. Callahan; Y. Anderson; P. Valora; L. Soderblom

2010-01-01

39

Radiogenic Strontium-87 as an Index of Geologic Processes.  

PubMed

The abundance of radiogenic Sr(87) relative to Sr(86) at the time of crystallization has been determined for 45 rocks. The total range in the ratio Sr(87)/Sr(86) is less than 2 percent. Ratios for recent lavas range from 0.702 to 0.711. Oceanic basalts are closely grouped at 0.703, whereas ratios for continental volcanic rocks spread from 0.702 to 0.711. Among the volcanic rocks, ranging from basalt to rhyolite, no correlation was found between original ratio and rock type. Older mafic and felsic rocks that include both plutonic and extrusive types also cover this same range in original Sr(87)/Sr(86) ratios; however, there is a definite trend with geologic time. Precambrian rocks give values as low as 0.700. The data indicate that Sr(87)/Sr(86) of the weathering crust has changed 1.1 percent in 3000 million years, while the ratio in the mantle has changed no more than 0.5 percent. PMID:17837503

Hedge, C E; Walthall, F G

1963-06-14

40

The importance of U-series dating for understanding the Quaternary geology  

E-print Network

at the con- sequential geomorphology and sedimentology. Of particular importance to the project significantly more developed sedimentology. The sedimentology of the Kyrenia Terrace is a relatively mature

41

Assessment of effectiveness of geologic isolation systems. Geologic factors in the isolation of nuclear waste: evaluation of long-term geomorphic processes and catastrophic events  

SciTech Connect

SRI International has projected the rate, duration, and magnitude of geomorphic processes and events in the Southwest and Gulf Coast over the next million years. This information will be used by the Department of Energy`s Pacific Northwest Laboratory (PNL) as input to a computer model, which will be used to simulate possible release scenarios and the consequences of the release of nuclear waste from geologic containment. The estimates in this report, although based on best scientific judgment, are subject to considerable uncertainty. An evaluation of the Quaternary history of the two study areas revealed that each had undergone geomorphic change in the last one million years. Catastrophic events were evaluated in order to determine their significance to the simulation model. Given available data, catastrophic floods are not expected to occur in the two study areas. Catastrophic landslides may occur in the Southwest, but because the duration of the event is brief and the amount of material moved is small in comparison to regional denudation, such events need not be included in the simulation model. Ashfalls, however, could result in removal of vegetation from the landscape, thereby causing significant increases in erosion rates. Because the estimates developed during this study may not be applicable to specific sites, general equations were presented as a first step in refining the analysis. These equations identify the general relationships among the important variables and suggest those areas of concern for which further data are required. If the current model indicates that geomorphic processes (taken together with other geologic changes) may ultimately affect the geologic containment of nuclear waste, further research may be necessary to refine this analysis for application to specific sites.

Mara, S.J.

1980-03-01

42

Techniques for determining probabilities of events and processes affecting the performance of geologic repositories  

SciTech Connect

The US Environmental Protection Agency has established a standard for the performance of geologic repositories for the disposal of radioactive waste. This standard is probabilistic in nature, but the methods for determining probabilities of events and processes of interest in implementing such a standard are still being developed. Decision Theory, which involves Bayesian probability techniques, can serve as a framework for estimating the probability of occurrence of processes and events that are likely to disrupt a geologic repository. This report presents the mathematical basis for such a methodology and demonstrates an application of it in three areas: climate change, tectonic events, and human intrusion. 125 refs., 27 figs., 14 tabs.

Apostolakis, G. (California Univ., Los Angeles, CA (USA)); Bras, R. (Bras (R.L.) Consulting Engineers, Lexington, MA (USA)); Price, L. (Sandia National Labs., Albuquerque, NM (USA)); Valdes, J. (Texas A and M Univ., College Station, TX (USA)); Wahi, K. (GRAM, Inc., Albuquerque, NM (USA)); Webb, E. (Wisconsin Univ., Madison, WI (USA))

1991-06-01

43

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.

44

Molecular Modeling of Environmentally Important Processes: Reduction Potentials  

ERIC Educational Resources Information Center

The increasing use of computational quantum chemistry in the modeling of environmentally important processes is described. The employment of computational quantum mechanics for the prediction of oxidation-reduction potential for solutes in an aqueous medium is discussed.

Lewis, Anne; Bumpus, John A.; Truhlar, Donald G.; Cramer, Christopher J.

2004-01-01

45

Techniques for determining probabilities of events and processes affecting the performance of geologic repositories: Literature review  

SciTech Connect

The US Environmental Protection Agency (EPA) has set a probabilistic standard for the performance of geologic repositories for the disposal of radioactive waste. This report treats not only geologic events and processes like fault movement, but also events and processes that arise from the relationship between human actions and geology, like drilling for resources, and some that arise from nongeologic processes that in turn affect a geologic process, like climatic change. It reviews the literature in several fields to determine whether existing probabilistic methods for predicting events and processes are adequate for implementation of the standard. Techniques exist for qualitatively estimating the potential for endowment of portions of earth's crust with mineral resources, but such techniques cannot easily predict whether or not human intrusion will occur. The EPA standard offers explicit guidance for the treatment of human intrusion, however. A complete method for climatic prediction could be assembled from existing techniques, although such a combination has not been tested. Existing techniques to support a probabilistic assessment of tectonic activity and seismic hazard at a repository site should be combined with expert judgment in performance assessments. Depending on the regional setting, either analytic techniques or expert judgment may be appropriate in assigning probabilities to volcanic activity. The individual chapters of this report have been cataloged separately.

Hunter, R.L.; Mann, C.J. (eds.)

1989-06-01

46

Impact of food processing industry on geology, soil and ecology: The Nigerian experience  

Microsoft Academic Search

In developing countries it is common to cite industries without carrying out environmental impact assessment. This is the case of the two industries audited in this study. It becomes necessary therefore to audit food processing industries in Nigeria to determine their impact on geology, soil and ecology. This will enhance a cleaner and healthier environment. In this study the impact

Ogbonnaya Chukwu

47

Geologic versus wildfire controls on hillslope processes and debris flow initiation in the Green River canyons  

E-print Network

debris flows over the study period, whereas only 7% of the unburned catchments did. Thus, fire was not the primary driver of debris flows, but fire-related events did contribute to the increased debris flowGeologic versus wildfire controls on hillslope processes and debris flow initiation in the Green

Pederson, Joel L.

48

Time-lapse motion picture technique applied to the study of geological processes  

USGS Publications Warehouse

Light-weight, battery-operated timers were built and coupled to 16-mm motion-picture cameras having apertures controlled by photoelectric cells. The cameras were placed adjacent to Emmons Glacier on Mount Rainier. The film obtained confirms the view that exterior time-lapse photography can be applied to the study of slow-acting geologic processes.

Miller, R. D.; Crandell, D. R.

1959-01-01

49

Roles of methane and carbon dioxide in geological processes on Mars  

Microsoft Academic Search

We discuss in this paper possible roles of methane and carbon dioxide in geological processes on Mars. These volatiles in the martian crust may migrate upward from their sources either directly or via various traps (structural, sedimentary, ground ice, gas hydrates). They are then likely emitted to the atmosphere by seepage or through diverse vent structures. Though gas hydrates have

Goro Komatsu; Gian Gabriele Ori; Marco Cardinale; James M. Dohm; Victor R. Baker; David A. Vaz; Ryo Ishimaru; Noriyuki Namiki; Takafumi Matsui

2011-01-01

50

The large impact process inferred from the geology of lunar multiring basins  

NASA Technical Reports Server (NTRS)

The nature of the impact process has been inferred through the study of the geology of a wide variety of impact crater types and sizes. Some of the largest craters known are the multiring basins found in ancient terrains of the terrestrial planets. Of these features, those found on the Moon possess the most extensive and diverse data coverage, including morphological, geochemical, geophysical, and sample data. The study of the geology of lunar basins over the past 10 years has given us a rudimentary understanding of how these large structures have formed and evolved. The topics covered include basin morphology, basin ejecta, basin excavation, and basin ring formation.

Spudis, Paul D.

1992-01-01

51

Elucidating geological and biological processes underlying the diversification of Sulawesi tarsiers.  

PubMed

Because of their exceptionally long independent evolution, a range diminution of their Eocene relatives, and a remarkable subsequent diversification in Southeast Asia, tarsiers are of particular importance to evolutionary primatologists. Little is known, however, on the processes shaping the radiation of these small enigmatic primates-especially on the Indonesian island of Sulawesi, their center of endemism. Geological reconstructions and progress in applying DNA sequence information to divergence dating now provide us with the tools and background to comprehend tarsier dispersal. Here, we describe effects of plate-tectonic movements, Pleistocene sea level changes, and hybridization on the divergence of central Sulawesi tarsiers. We analyzed 12 microsatellites, the cytochrome b gene, the hypervariable region I of the mitochondrial control region, and the sex-determining region on the Y-chromosome from 144 specimens captured along a transect crossing a species boundary and a contact zone between 2 microplates. Based on these differentially inherited genetic markers, geographic information, and recordings of vocalizations, we demonstrate that the species boundary coincides with a tectonic suture. We estimate the most recent common ancestor of the 2 taxa to have lived 1.4 Mya, we describe asymmetrical introgressive hybridization, and we give evidence of unbiased dispersal in one species and male-biased dispersal in another species. This study exemplifies that the distribution of tarsier acoustic forms on Sulawesi is consistent with the allocation of genetic variability and that plate-tectonic and glacial events have left traceable marks in the biogeography of this island's unique fauna. PMID:19451646

Merker, Stefan; Driller, Christine; Perwitasari-Farajallah, Dyah; Pamungkas, Joko; Zischler, Hans

2009-05-26

52

Node importance for dynamical process on networks: a multiscale characterization.  

PubMed

Defining the importance of nodes in a complex network has been a fundamental problem in analyzing the structural organization of a network, as well as the dynamical processes on it. Traditionally, the measures of node importance usually depend either on the local neighborhood or global properties of a network. Many real-world networks, however, demonstrate finely detailed structure at various organization levels, such as hierarchy and modularity. In this paper, we propose a multiscale node-importance measure that can characterize the importance of the nodes at varying topological scale. This is achieved by introducing a kernel function whose bandwidth dictates the ranges of interaction, and meanwhile, by taking into account the interactions from all the paths a node is involved. We demonstrate that the scale here is closely related to the physical parameters of the dynamical processes on networks, and that our node-importance measure can characterize more precisely the node influence under different physical parameters of the dynamical process. We use epidemic spreading on networks as an example to show that our multiscale node-importance measure is more effective than other measures. PMID:21456849

Zhang, Jie; Xu, Xiao-Ke; Li, Ping; Zhang, Kai; Small, Michael

2011-03-01

53

The MESSENGER mission to Mercury: new insights into geological processes and evolution  

NASA Astrophysics Data System (ADS)

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, a part of NASA's Discovery Program, was designed to answer six questions [1]: (1) What planetary formational processes led to Mercury's high ratio of metal to silicate? (2) What is the geological history of Mercury? (3) What are the nature and origin of Mercury's magnetic field? (4) What are the structure and state of Mercury's core? (5) What are the radar-reflective materials at Mercury's poles? (6) What are the important volatile species and their sources and sinks near Mercury? MESSENGER is currently midway through a complex interplanetary cruise phase that involves three flybys of Mercury. The first of these, on 14 January 2008, provided important new information relating to several of the questions above [2-13]. Here we summarize observations made during the flyby that are most relevant to new insights about geological processes that have operated on Mercury and implications for the planet's history [3, 8-13]. The instruments that provided the most direct information on the geological history of Mercury during this first encounter were the Mercury Dual Imaging System (MDIS) [14], the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) [15], and the Mercury Laser Altimeter (MLA) [16]. Among the many specific questions remaining following the Mariner 10 mission to Mercury (1974- 1975) were (1) the level of mineralogical and compositional diversity of the crust, which appeared relatively bland in Mariner 10 data, (2) the nature of the rest of the huge Caloris impact basin seen only partially in Mariner 10 images, (3) the origin of the extensive plains observed on the surface (ponded impact ejecta or extrusive lava flows?), (4) the diversity and global distribution of tectonic features that have deformed the crust and their implications for strain as a function of time, and (5) the bombardment chronology and geological history of Mercury [1, 17-19]. The viewing geometry for the first MESSENGER encounter of Mercury [1] provided important information on these questions from image and remote sensing data on an additional 20% of the surface of Mercury not seen by Mariner 10, as well as comprehensive views of the Caloris basin and its surroundings. MESSENGER MDIS multi-spectral images [8-10] revealed a relatively low-reflectance surface with three broad units identified from reflectance and spectral slope in the wavelength range 0.4-1.0 ?m. These new data helped to confirm the diversity of color units detected in re-processed Mariner 10 color-ratio images [20] and to extend the analysis to larger areas of Mercury. One of these new units is higher in reflectance and forms relatively red plains material that corresponds to a distinct class of smooth plains; these plains, on the basis of their sharp contacts with other units, are interpreted to have been emplaced volcanically. A second unit is represented by lowerreflectance material with a lesser spectral slope and is interpreted to form a distinct crustal component enriched in opaque minerals and possibly more common at depth. A spectrally intermediate terrain appears to form the majority of the upper crust in the newly observed area. Several other spectrally distinct units are found in local regions: (1) moderately high-reflectance, relatively reddish material associated with rimless depressions and located at several places along the interior margin of the Caloris basin rim; (2) highreflectance deposits observed in some impact crater floors; and (3) fresh crater ejecta that is less modified by space weathering than older surface materials. MASCS spectrometer data [9,15] show absorption and spectral slope properties of resolved spectra that are indicative of differences in composition and regolith maturation processes among color units defined by MDIS. Mid-ultraviolet to near-infrared reflectance observations of the surface revealed the presence of a previously unobserved ultraviolet absorption feature that suggests a low FeO content (<2-3 weight %) in silicates in averag

Head, James W., III; Solomon, Sean C.; McNutt, Ralph L., Jr.; Blewett, David T.; Chapman, Clark R.; Domingue, Deborah L.; Evans, Larry G.; Gillis-Davis, Jeffrey J.; Hawkins, S. Edward, III; Helbert, Jörn; Holsclaw, Gregory M.; Izenberg, Noam R.; McClintock, William E.; McCoy, Timothy J.; Merline, William J.; Murchie, Scott L.; Nittler, Larrz R.; Phillips, Roger J.; Prockter, Louise M.; Robinson, Mark S.; Sprague, Ann L.; Strom, Robert G.; Vilas, Faith; Watters, Thomas R.; Zuber, Maria T.

2008-09-01

54

Coupled THMC processes in Geological Media using Stochastic Discrete Fractured Network. Application to HDR Geothermal Reservoirs  

NASA Astrophysics Data System (ADS)

Hot Dry Rock (HDR) fractured geological formations, where the assumption of homogeneity is restrictive, are very important thermo-hydrological reservoirs. In the present study, the fractured media was treated as a heterogeneous network of stochastically generated discrete fractures (SDFN). The flow at the fracture scale was derived analytically using Laplace transform. Flow at the formation level was then achieved by combining the solution of the generated individual fractures. To validate the proposed model, one-, two- and three- dimensional problems were investigated. An experimental high pressure water injection test conducted at Soultz-sous-Forêts in Alsace, France, was simulated. Results indicated that the mechanical properties of the media influenced by the injection pressure must be incorporated into the proposed model. In particular, changes in the hydraulic conductivity and the storage coefficient as function of the effective stresses appear to be quite significant. Consequently, the model was extended to take into account the mechanical stresses and was reapplied to the flow injection test. The hydro-mechanical model results showed significant improvements between the simulated and observed pressure time series. Heat extraction from HDR is not limited however to the hydrological phenomena discussed thus far, and therefore, thermal and geochemical processes must be included. A one-dimensional model was developed which takes into account the equilibrium and/or non-equilibrium transport of the chemical species and the water-rock interaction. Thermal processes were modeled using a double porosity approach. The hydrothermal and chemical transport at the formation level was obtained by simultaneously combining the solution of the stochastically generated individual fractures. Finally to demonstrate the applicability of the proposed hydro-thermo-mechanical and chemical (THMC) model, a calcite precipitation example is presented.

Ezzedine, S.

2008-12-01

55

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

SciTech Connect

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 be effectively utilized in the applications of seismic imaging and vehicle tracking where rapid (minutes to hours) and real-time analysis is required. The goal of this project is to build capabilities in acquisition system design, utilization of full three-dimensional (3D) finite difference modeling, as well as statistical characterization of geological heterogeneity. Such capabilities coupled with a rapid field analysis methodology based on matched field processing are applied to problems associated with surveillance, battlefield management, finding hard and deeply buried targets, and portal monitoring. This project, in support of LLNL's national-security mission, benefits the U.S. military and intelligence community. Fiscal year (FY) 2003 was the final year of this project. In the 2.5 years this project has been active, numerous and varied developments and milestones have been accomplished. A wireless communication module for seismic data was developed to facilitate rapid seismic data acquisition and analysis. The E3D code was enhanced to include topographic effects. Codes were developed to implement the Karhunen-Loeve (K-L) statistical methodology for generating geological heterogeneity that can be utilized in E3D modeling. The matched field processing methodology applied to vehicle tracking and based on a field calibration to characterize geological heterogeneity was tested and successfully demonstrated in a tank tracking experiment at the Nevada Test Site. A three-seismic-array vehicle tracking testbed was installed on site at LLNL for testing real-time seismic tracking methods. A field experiment was conducted over a tunnel at the Nevada Site that quantified the tunnel reflection signal and, coupled with modeling, identified key needs and requirements in experimental layout of sensors. A large field experiment was conducted at the Lake Lynn Laboratory, a mine safety research facility in Pennsylvania, over a tunnel complex in realistic, difficult conditions. This experiment gathered the necessary data for a full 3D attempt to apply the methodology. The experiment also collected data to analyze the capabilities to detect and locate in-tunnel explosions for mine safety and other applications. In FY03 specifically, a large and complex simulation experiment was conducted that tested the full modeling-based approach to geological characterization using E2D, the K-L statistical methodology, and matched field processing applied to tunnel detection with surface seismic sensors. The simulation validated the full methodology and the need for geological heterogeneity to be accounted for in the overall approach. The Lake Lynn site area was geologically modeled using the code Earthvision to produce a 32 million node 3D model grid for E3D. Model linking issues were resolved and a number of full 3D model runs were accomplished using shot locations that matched the data. E3D-generated wavefield movies showed the reflection signal would be too small to be observed in the data due to trapped and attenuated energy in the weathered layer. An analysis of the few sensors coupled to bedrock did not improve the reflection signal strength sufficiently because the shots, though buried, were within the surface layer and hence attenuated. Ability to model a complex 3D geological structure and calculate synthetic seismograms that are in good agreement with actual data (especially for surface waves and below the complex weathered layer) was demonstrated. We conclude that E3D is a powerful tool for assessing the conditions under which a tunnel could be detected in a specific geological setting. Finally, the Lak

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

2003-10-29

56

Understanding geological processes: Visualization of rigid and non-rigid transformations  

NASA Astrophysics Data System (ADS)

Visualizations are used in the geological sciences to support reasoning about structures and events. Research in cognitive sciences offers insights into the range of skills of different users, and ultimately how visualizations might support different users. To understand the range of skills needed to reason about earth processes we have developed a program of research that is grounded in the geosciences' careful description of the spatial and spatiotemporal patterns associated with earth processes. In particular, we are pursuing a research program that identifies specific spatial skills and investigates whether and how they are related to each other. For this study, we focus on a specific question: Is there an important distinction in the geosciences between rigid and non-rigid deformation? To study a general spatial thinking skill we employed displays with non-geological objects that had been altered by rigid change (rotation), and two types of non-rigid change ("brittle" (or discontinuous) and "ductile" (or continuous) deformation). Disciplinary scientists (geosciences and chemistry faculty), and novices (non-science faculty and undergraduate psychology students) answered questions that required them to visualize the appearance of the object before the change. In one study, geologists and chemists were found to be superior to non-science faculty in reasoning about rigid rotations (e.g., what an object would look like from a different perspective). Geologists were superior to chemists in reasoning about brittle deformations (e.g., what an object looked like before it was broken - here the object was a word cut into many fragments displaced in different directions). This finding is consistent with two hypotheses: 1) Experts are good at visualizing the types of changes required for their domain; and 2) Visualization of rigid and non-rigid changes are not the same skill. An additional important finding is that there was a broad range of skill in both rigid and non-rigid reasoning within the panels of science experts. In a second study, individual differences in reasoning about brittle deformations were correlated with reasoning about ductile deformations (e.g., what a bent plastic sheet would look like when unbent). Students who were good at visualizing what something looked like before it was broken were also good at visualizing what something looked like before it was bent, and this skill was not correlated to reasoning about rigid rotations. These findings suggest the cognitive processes that support reasoning about rigid and non-rigid events may differ and thus may require different types of support and training. We do not know if differences between experts and novices result from experience or self-selection, or both. Nevertheless, the range of spatial skill evinced by novices and experts strongly argues for designing visualizations to support a variety of users.

Shipley, T. F.; Atit, K.; Manduca, C. A.; Ormand, C. J.; Resnick, I.; Tikoff, B.

2012-12-01

57

Differential preservation in the geologic record of intraoceanic arc sedimentary and tectonic processes  

USGS Publications Warehouse

Records of ancient intraoceanic arc activity, now preserved in continental suture zones, are commonly used to reconstruct paleogeography and plate motion, and to understand how continental crust is formed, recycled, and maintained through time. However, interpreting tectonic and sedimentary records from ancient terranes after arc–continent collision is complicated by preferential preservation of evidence for some arc processes and loss of evidence for others. In this synthesis we examine what is lost, and what is preserved, in the translation from modern processes to the ancient record of intraoceanic arcs. Composition of accreted arc terranes differs as a function of arc–continent collision geometry. ‘Forward-facing’ collision can accrete an oceanic arc on to either a passive or an active continental margin, with the arc facing the continent and colliding trench- and forearc-side first. In a ‘backward-facing’ collision, involving two subduction zones with similar polarity, the arc collides backarc-first with an active continental margin. The preservation of evidence for contemporary sedimentary and tectonic arc processes in the geologic record depends greatly on how well the various parts of the arc survive collision and orogeny in each case. Preservation of arc terranes likely is biased towards those that were in a state of tectonic accretion for tens of millions of years before collision, rather than tectonic erosion. The prevalence of tectonic erosion in modern intraoceanic arcs implies that valuable records of arc processes are commonly destroyed even before the arc collides with a continent. Arc systems are most likely to undergo tectonic accretion shortly before forward-facing collision with a continent, and thus most forearc and accretionary-prism material in ancient arc terranes likely is temporally biased toward the final stages of arc activity, when sediment flux to the trench was greatest and tectonic accretion prevailed. Collision geometry and tectonic erosion vs. accretion are important controls on the ultimate survival of material from the trench, forearc, arc massif, intra-arc basins, and backarc basins, and thus on how well an ancient arc terrane preserves evidence for tectonic processes such as subduction of aseismic ridges and seamounts, oblique plate convergence, and arc rifting. Forward-facing collision involves substantial recycling, melting, and fractionation of continent-derived material during and after collision, and so produces melts rich in silica and incompatible trace elements. As a result, forward-facing collision can drive the composition of accreted arc crust toward that of average continental crust.

Draut, Amy; Clift, Peter D.

2013-01-01

58

Martian planetwide crater distributions - Implications for geologic history and surface processes  

NASA Technical Reports Server (NTRS)

Three different diameter size ranges are considered in connection with the Martian crater distribution, taking into account small craters from 0.6 to 1.2 km, intermediate-sized craters from 4 to 10 km, and large craters with diameters exceeding 20 km. One of the objectives of the investigation reported is to establish the effects of eolian processes in the modification of craters in the different size ranges. Another objective is concerned with a description of the genetic relationships among the three size ranges of craters. Observables related to the relative age of geologic provinces are to be separated from observables related to geographic variations in eolian transport and deposition. Lunar and Martian cratering histories are compared as a basis for establishing relative and absolute time scales for the geological evolution of Mars.

Soderblom, L. A.; Condit, C. D.; West, R. A.; Herman, B. M.; Kreidler, T. J.

1974-01-01

59

Process for stabilizing rock and coal formations by bonding these formations to themselves or other geological formations  

Microsoft Academic Search

The invention relates to a process for stabilizing rock and coal formations by bonding them to each other or to other geological formations. The bonding material is a reactive organic polyisocyanate-polyol mixture which may contain a catalyst.

D. Arndt; D. Hobein

1984-01-01

60

Canada's Deep Geological Repository for Used Nuclear Fuel - Geo-scientific Site Evaluation Process - 13117  

SciTech Connect

The Nuclear Waste Management Organization (NWMO) is responsible for implementing Adaptive Phased Management (APM), the approach selected by the Government of Canada for long-term management of used nuclear fuel generated by Canadian nuclear reactors. The ultimate objective of APM is the centralized containment and isolation of Canada's used nuclear fuel in a Deep Geological Repository in a suitable rock formation at a depth of approximately 500 meters (m) (1,640 feet [ft]). In May 2010, the NWMO published a nine-step site selection process that serves as the road map to decision-making on the location for the deep geological repository. The safety and appropriateness of any potential site will be assessed against a number of factors, both technical and social in nature. The selected site will be one that can be demonstrated to be able to safely contain and isolate used nuclear fuel, protecting humans and the environment over the very long term. The geo-scientific suitability of potential candidate sites will be assessed in a stepwise manner following a progressive and thorough site evaluation process that addresses a series of geo-scientific factors revolving around five safety functions. The geo-scientific site evaluation process includes: Initial Screenings; Preliminary Assessments; and Detailed Site Evaluations. As of November 2012, 22 communities have entered the site selection process (three in northern Saskatchewan and 18 in northwestern and southwestern Ontario). (authors)

Blyth, Alec; Ben Belfadhel, Mahrez; Hirschorn, Sarah; Hamilton, Duncan; McKelvie, Jennifer [Nuclear Waste Management Organization, 22 St. Clair Avenue East, Toronto, Ontario M4T 2S3 (Canada)] [Nuclear Waste Management Organization, 22 St. Clair Avenue East, Toronto, Ontario M4T 2S3 (Canada)

2013-07-01

61

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

62

Thermophilic bacilli and their importance in dairy processing.  

PubMed

The thermophilic bacilli, such as Anoxybacillus flavithermus and Geobacillus spp., are an important group of contaminants in the dairy industry. Although these bacilli are generally not pathogenic, their presence in dairy products is an indicator of poor hygiene and high numbers are unacceptable to customers. In addition, their growth may result in milk product defects caused by the production of acids or enzymes, potentially leading to off-flavours. Dairy thermophiles are usually selected for by the conditions during dairy manufacture. These bacteria are able to grow in sections of dairy manufacturing plants where temperatures reach 40-65°C. Furthermore, because they are spore formers, they are difficult to eliminate. In addition, they exhibit a wide temperature growth range, exhibit a fast growth rate (generation time of approximately 15-20 min) and tend to readily form biofilms. Many strategies have been tested to remove, prevent and/or delay the formation of thermophilic bacilli biofilms in dairy manufacture, but with limited success. This is, in part, because little is known about the structure and composition of thermophilic bacilli biofilms in general and, more specifically, in milk processing environments. Therefore, new cleaning regimes often do not target the problem optimally. A greater understanding of the structure of thermophilic biofilms within the context of the milk processing environment and their link with spore formation is needed to develop better control measures. This review discusses the characteristics and food spoilage potential, enumeration and identification methods for the thermophilic bacilli, as well as their importance to dairy manufacture, with an emphasis on biofilm development and spore formation. PMID:21047695

Burgess, Sara A; Lindsay, Denise; Flint, Steve H

2010-12-15

63

Processes that initiate turbidity currents and their influence on turbidites: A marine geology perspective  

USGS Publications Warehouse

How the processes that initiate turbidity currents influence turbidite deposition is poorly understood, and many discussions in the literature rely on concepts that are overly simplistic. Marine geological studies provide information on the initiation and flow path of turbidity currents, including their response to gradient. In case studies of late Quaternary turbidites on the eastern Canadian and western U.S. margins, initiation processes are inferred either from real-time data for historical flows or indirectly from the age and contemporary paleogeography, erosional features, and depositional record. Three major types of initiation process are recognized: transformation of failed sediment, hyperpycnal flow from rivers or ice margins, and resuspension of sediment near the shelf edge by oceanographic processes. Many high-concentration flows result from hyperpycnal supply of hyperconcentrated bedload, or liquefaction failure of coarse-grained sediment, and most tend to deposit in slope conduits and on gradients < 0.5?? at the base of slope and on the mid fan. Highly turbulent flows, from transformation of retrogressive failures and from ignitive flows that are triggered by oceanographic processes, tend to cannibalize these more proximal sediments and redeposit them on lower gradients on the basin plain. Such conduit flushing provides most of the sediment in large turbidites. Initiation mechanism exerts a strong control on the duration of turbidity flows. In most basins, there is a complex feedback between different types of turbidity-current initiation, the transformation of the flows, and the associated slope morphology. As a result, there is no simple relationship between initiating process and type of deposit. ?? 2009, SEPM (Society for Sedimentary Geology).

Piper, David J.W.; Normark, William R.

2009-01-01

64

Importance of using complementary process analyzers for the process monitoring, analysis, and understanding of freeze drying.  

PubMed

The aim of the present paper is to demonstrate the importance of using complementary process analyzers (PAT tools) for the process monitoring, analysis, and understanding of freeze drying. A mannitol solution was used as a model system. Raman spectroscopic, near-infrared (NIR) spectroscopic, plasma emission spectroscopic, and wireless temperature measurements (TEMPRIS) were simultaneously performed in-line and real-time during each freeze-drying experiment. The combination of these four process analyzers to monitor a freeze-drying process is unique. The Raman and NIR data were analyzed using principal component analysis (PCA) and multivariate curve resolution (MCR), while the plasma emission spectroscopic and wireless temperature measurement data were analyzed using univariate data analysis. It was shown that the considered process analyzers do not only complement but also mutually confirm each other with respect to process step end points, physical phenomena occurring during freeze drying (process understanding), and product characterization (solid state). Furthermore and most important, the combined use of the process analyzers helped to identify flaws in previous studies in which these process analyzers were studied individually. Process analyzers might wrongly indicate that some process steps are fulfilled. Finally, combining the studied process analyzers also showed that more information per process analyzer can be obtained than previously described. A combination of Raman and plasma emission spectroscopy seems favorable for the monitoring of nearly all critical freeze-drying process aspects. PMID:19681620

De Beer, T R M; Wiggenhorn, M; Veillon, R; Debacq, C; Mayeresse, Y; Moreau, B; Burggraeve, A; Quinten, T; Friess, W; Winter, G; Vervaet, C; Remon, J P; Baeyens, W R G

2009-09-15

65

No geology without marine geology  

Microsoft Academic Search

A brief review is offered of the many problems where knowledge of the ocean floors and of marine processes in shallow water is indispensable for the further advancement of geology. The subject of turbidity currents is treated in greater detail, to demonstrate the interrelation of several aspects of marine geology with sedimentologic and paleogeographic investigations. It is obvious that the

P. H Kuenen

2002-01-01

66

Geoelectrical signals of geologic and hydrologic processes in a fringing reef lagoon setting  

NASA Astrophysics Data System (ADS)

Coastal groundwater may discharge into nearshore and offshore waters forced by terrestrial fluxes, controlled by local geology, and modulated by the hydrodynamics of littoral water. We investigated the electrical signature of these features with a dense, multiscale network of electrical resistivity tomography (ERT) surveys in the Muri Lagoon of Rarotonga, Cook Islands. The ERT surveys spanned from onshore to 400 m into the lagoon and used standard electrodes on land and across the foreshore, submerged electrodes in the shallow subtidal zone, and floating electrodes towed throughout the reef lagoon by a boat. ERT surveys on land mapped a typical freshwater lens underlain by a saltwater wedge, but with possible deviations from the classical model due to an adjacent tidal creek. Further inland, ERT surveys imaged a layer of lava flow deposits that is potentially a confining hydrogeologic unit; this unit was used to constrain the expected electrical resistivity of these deposits below the lagoon. ERT surveys across the intertidal zone and into the lagoon indicated fresh groundwater and porewater salinity patterns consistent with previous small-scale studies including the seaward extension of fresh groundwater pathways to the lagoon. Electrical resistivity (ER) variations in the lagoon subsurface highlighted heterogeneities in the lagoon structure that may focus submarine groundwater discharge (SGD) through previously unknown buried lava flow deposits in the lagoon. A transition to higher ER values near the reef crest is consistent with the ER signature of porosity reduction due to ongoing differential cementation of reef deposits across the lagoon. The imaged coastal hydrostratigraphic heterogeneity may thus control terrestrial and marine porewater mixing, support SGD, and provide the pathways for groundwater and the materials it transports into the lagoon. This hydrogeophysical investigation highlighted the spatial heterogeneity of submarine coastal geology and its hydrogeologic control in a reef lagoon setting, but is likely to occur in many similar coastal settings. Ignoring geologic complexity can result in mischaracterization of SGD and other coastal groundwater processes at many spatial scales.

Befus, Kevin M.; Cardenas, M. Bayani; Tait, Douglas R.; Erler, Dirk V.

2014-09-01

67

US GEOLOGICAL SURVEY'S NATIONAL SYSTEM FOR PROCESSING AND DISTRIBUTION OF NEAR REAL-TIME HYDROLOGICAL DATA.  

USGS Publications Warehouse

The US Geological Survey is utilizing a national network of more than 1000 satellite data-collection stations, four satellite-relay direct-readout ground stations, and more than 50 computers linked together in a private telecommunications network to acquire, process, and distribute hydrological data in near real-time. The four Survey offices operating a satellite direct-readout ground station provide near real-time hydrological data to computers located in other Survey offices through the Survey's Distributed Information System. The computerized distribution system permits automated data processing and distribution to be carried out in a timely manner under the control and operation of the Survey office responsible for the data-collection stations and for the dissemination of hydrological information to the water-data users.

Shope, Jr. , William, G.

1987-01-01

68

The importance of dreams and action in the adolescent process.  

PubMed

The author argues that after puberty dreams and action are indicators of the capacity of the psychic apparatus to perform the work of binding drive energy. He notes that the development of adult sexuality always involves risk and that effective dream activity affords a definitive solution to the problem of incestuous and parricidal temptations, which attain an unprecedented pitch of intensity with the onset of sexual and procreative potency in adolescence. The author illustrates his thesis by the case of an adolescent patient with particular sexual pathology who broke down at the age of 17 and who, once he became able to dream in the course of analysis, had less need to act out. A 'work of the negative' is presented as a paradoxical but important element in psychic development. Dreaming and action are stated to be inseparable and to constitute an essential safety valve that facilitates the developmental process. A discussion of the connections between dreams and initiation leads to some ethnological considerations on sexuality and society, and the paper ends with a plea not to overlook the death drive. PMID:8789165

Ladame, F

1995-12-01

69

Seafloor Eruptions Offer a Teachable Moment to Help SEAS Students Understand Important Geological and Ecological Processes  

Microsoft Academic Search

In education parlance, a teachable moment is an opportunity that arises when students are engaged and primed to learn, typically in response to some memorable event. Earthquakes, volcanic eruptions, even natural disasters, if meaningful to the student, often serve to catalyze intense learning. Recent eruptions at the East Pacific Rise offer a potential teachable moment for students and teachers involved

L. Goehring; C. S. Williams

2006-01-01

70

27 CFR 41.1 - Importation of tobacco products, cigarette papers and tubes, and processed tobacco.  

Code of Federal Regulations, 2010 CFR

...false Importation of tobacco products, cigarette papers and tubes, and processed tobacco...TOBACCO IMPORTATION OF TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND PROCESSED TOBACCO...1 Importation of tobacco products, cigarette papers and tubes, and processed...

2010-04-01

71

Separating Macroecological Pattern and Process: Comparing Ecological, Economic, and Geological Systems  

PubMed Central

Theories of biodiversity rest on several macroecological patterns describing the relationship between species abundance and diversity. A central problem is that all theories make similar predictions for these patterns despite disparate assumptions. A troubling implication is that these patterns may not reflect anything unique about organizational principles of biology or the functioning of ecological systems. To test this, we analyze five datasets from ecological, economic, and geological systems that describe the distribution of objects across categories in the United States. At the level of functional form (‘first-order effects’), these patterns are not unique to ecological systems, indicating they may reveal little about biological process. However, we show that mechanism can be better revealed in the scale-dependency of first-order patterns (‘second-order effects’). These results provide a roadmap for biodiversity theory to move beyond traditional patterns, and also suggest ways in which macroecological theory can constrain the dynamics of economic systems. PMID:25383874

Blonder, Benjamin; Sloat, Lindsey; Enquist, Brian J.; McGill, Brian

2014-01-01

72

Improved understanding of geologic CO{sub 2} storage processes requires risk-driven field experiments  

SciTech Connect

The need for risk-driven field experiments for CO{sub 2} geologic storage processes to complement ongoing pilot-scale demonstrations is discussed. These risk-driven field experiments would be aimed at understanding the circumstances under which things can go wrong with a CO{sub 2} capture and storage (CCS) project and cause it to fail, as distinguished from accomplishing this end using demonstration and industrial scale sites. Such risk-driven tests would complement risk-assessment efforts that have already been carried out by providing opportunities to validate risk models. In addition to experimenting with high-risk scenarios, these controlled field experiments could help validate monitoring approaches to improve performance assessment and guide development of mitigation strategies.

Oldenburg, C.M.

2011-06-01

73

Molecular connections between nuclear and ciliary import processes  

PubMed Central

As an organelle, the cilium contains a unique complement of protein and lipid. Recent work has begun to shed light on the mechanisms that regulate entry of ciliary proteins into the compartment. Here, we focus on the mechanisms that regulate ciliary entry of cytosolic molecules. Studies have revealed a size exclusion mechanism for ciliary entry that is similar to the barrier to nuclear entry. Active import into the ciliary compartment involves nuclear trafficking components including importins, a Ran-guanosine triphosphate gradient, and nucleoporins. Together, this work indicates that nuclei and cilia share molecular, structural and mechanistic components that regulate import into the compartments. PMID:23985042

2013-01-01

74

Thermophilic bacilli and their importance in dairy processing  

Microsoft Academic Search

The thermophilic bacilli, such as Anoxybacillus flavithermus and Geobacillus spp., are an important group of contaminants in the dairy industry. Although these bacilli are generally not pathogenic, their presence in dairy products is an indicator of poor hygiene and high numbers are unacceptable to customers. In addition, their growth may result in milk product defects caused by the production of

Sara A. Burgess; Denise Lindsay; Steve H. Flint

2010-01-01

75

Antarctic Dry Valley analogs for Mars gullies: Geological setting and processes  

NASA Astrophysics Data System (ADS)

Malin and Edgett [1,2] initially described a class of young features on Mars that they termed gullies, consisting of an alcove, a channel and a fan. Restricted to middle and high latitude locations, these features were interpreted to have originated through processes related to the presence of liquid water (through groundwater discharge); the potential presence of liquid water on the surface of Mars currently or in the very recent geological past, when liquid water is metastable [3], generated a host of alternative explanations for the gullies [see summary in 4]. Detailed analysis of the conditions under which H2O could flow as a liquid in the current Mars environment shows a range of conditions under which gully-forming activity is possible [3,5]. Recent observations of changes in gullies, interpreted to mean that a few gullies are currently active [6], have intensified this discussion. Terrestrial analogs to martian environments may provide insight into the processes operating on Mars. For example, the nature of perennial saline springs forming channels on Axel Heiberg Island in the Canadian High Arctic has been used to support the argument that martian gullies formed from subsurface groundwater springs [7]. In this analysis we report on the results of ongoing [8-11] field studies in the Antarctic Dry Valleys (ADV), a hyperarid polar desert analog for Mars [11].

Head, J. W.; Marchant, D. R.; Dickson, J. L.; Levy, J. S.; Morgan, G. A.

2008-09-01

76

Some important factors in the wet precipitation process of hydroxyapatite  

Microsoft Academic Search

The precipitation process considered here, involved the addition of orthophosphoric acid solution to a calcium hydroxide solution. Several parameters such as the effects of atmosphere controlling, pH, adding extra acid solution, the amount of stirring speed, and post-chemical treatment were studied. In order to study the thermal stability of synthesised powders, they were sintered for 2 h at 1200 °C

A Afshar; M Ghorbani; N Ehsani; M. R Saeri; C. C Sorrell

2003-01-01

77

Computational and Spectroscopic Investigations of the Molecular Scale Structure and Dynamics of Geologically Important Fluids and Mineral-Fluid Interfaces  

SciTech Connect

Research supported by this grant focuses on molecular scale understanding of central issues related to the structure and dynamics of geochemically important fluids, fluid-mineral interfaces, and confined fluids using computational modeling and experimental methods. Molecular scale knowledge about fluid structure and dynamics, how these are affected by mineral surfaces and molecular-scale (nano-) confinement, and how water molecules and dissolved species interact with surfaces is essential to understanding the fundamental chemistry of a wide range of low-temperature geochemical processes, including sorption and geochemical transport. Our principal efforts are devoted to continued development of relevant computational approaches, application of these approaches to important geochemical questions, relevant NMR and other experimental studies, and application of computational modeling methods to understanding the experimental results. The combination of computational modeling and experimental approaches is proving highly effective in addressing otherwise intractable problems. In 2006-2007 we have significantly advanced in new, highly promising research directions along with completion of on-going projects and final publication of work completed in previous years. New computational directions are focusing on modeling proton exchange reactions in aqueous solutions using ab initio molecular dynamics (AIMD), metadynamics (MTD), and empirical valence bond (EVB) approaches. Proton exchange is critical to understanding the structure, dynamics, and reactivity at mineral-water interfaces and for oxy-ions in solution, but has traditionally been difficult to model with molecular dynamics (MD). Our ultimate objective is to develop this capability, because MD is much less computationally demanding than quantum-chemical approaches. We have also extended our previous MD simulations of metal binding to natural organic matter (NOM) to a much longer time scale (up to 10 ns) for significantly larger systems. These calculations have allowed us, for the first time, to study the effects of metal cations with different charges and charge density on the NOM aggregation in aqueous solutions. Other computational work has looked at the longer-time-scale dynamical behavior of aqueous species at mineral-water interfaces investigated simultaneously by NMR spectroscopy. Our experimental NMR studies have focused on understanding the structure and dynamics of water and dissolved species at mineral-water interfaces and in two-dimensional nano-confinement within clay interlayers. Combined NMR and MD study of H2O, Na+, and Cl- interactions with the surface of quartz has direct implications regarding interpretation of sum frequency vibrational spectroscopic experiments for this phase and will be an important reference for future studies. We also used NMR to examine the behavior of K+ and H2O in the interlayer and at the surfaces of the clay minerals hectorite and illite-rich illite-smectite. This the first time K+ dynamics has been characterized spectroscopically in geochemical systems. Preliminary experiments were also performed to evaluate the potential of 75As NMR as a probe of arsenic geochemical behavior. The 75As NMR study used advanced signal enhancement methods, introduced a new data acquisition approach to minimize the time investment in ultra-wide-line NMR experiments, and provides the first evidence of a strong relationship between the chemical shift and structural parameters for this experimentally challenging nucleus. We have also initiated a series of inelastic and quasi-elastic neutron scattering measurements of water dynamics in the interlayers of clays and layered double hydroxides. The objective of these experiments is to probe the correlations of water molecular motions in confined spaces over the scale of times and distances most directly comparable to our MD simulations and on a time scale different than that probed by NMR. This work is being done in collaboration with Drs. C.-K. Loong, N. de Souza, and A.I. Kolesnikov at the Intense Pulsed

R. James Kirkpatrick; Andrey G. Kalinichev

2008-11-25

78

The importance of green chemistry in process research and development.  

PubMed

Green Chemistry or Sustainable Chemistry is defined by the Environmental Protection Agency as "the design of chemical products that reduce or eliminate the use of hazardous substances" In recent years there is a greater societal expectation that chemists and chemical engineers should produce greener and more sustainable chemical processes and it is likely that this trend will continue to grow over the next few decades. This tutorial review gives information on solvents and solvent selection, basic environmental metrics collection and three industrial case histories. All three case histories involve enzymatic chemistry. Pregabalin (Lyrica®) is produced using a lipase based resolution and is extremely unusual in that all four manufacturing steps to make pregabalin are performed in water. Sitagliptin (Januvia®) uses a transaminase in the final chemical step. Finally a rosuvastatin (Crestor®) intermediate is produced using a deoxy ribose aldolase (DERA) enzyme in which two carbon-carbon bonds and two chiral centres are formed in the same process step. PMID:21562677

Dunn, Peter J

2012-02-21

79

Investigating geologic features and processes: A field investigation for earth science students at Leif Erickson Park, Duluth, Minnesota.  

NSDL National Science Digital Library

This activity is a field investigation where students observe and interpret the rocks types, geologic features, and processes typical to the north shore of Lake Superior. Students use their data to develop questions that could be further investigated and to predict the sequence of events leading to the formation of these rocks and features.

Severson, Laurie

80

Application of ERTS images and image processing to regional geologic problems and geologic mapping in northern Arizona  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Computer image processing was shown to be both valuable and necessary in the extraction of the proper subset of the 200 million bits of information in an ERTS image to be applied to a specific problem. Spectral reflectivity information obtained from the four MSS bands can be correlated with in situ spectral reflectance measurements after path radiance effects have been removed and a proper normalization has been made. A detailed map of the major fault systems in a 90,000 sq km area in northern Arizona was compiled from high altitude photographs and pre-existing published and unpublished map data. With the use of ERTS images, three major fault systems, the Sinyala, Bright Angel, and Mesa Butte, were identified and their full extent measured. A byproduct of the regional studies was the identification of possible sources of shallow ground water, a scarce commodity in these regions.

Goetz, A. F. H. (principal investigator); Billingsley, F. C.; Gillespie, A. R.; Abrams, M. J.; Squires, R. L.; Shoemaker, E. M.; Lucchitta, I.; Elston, D. P.

1975-01-01

81

The importance of cost considerations in the systems engineering process  

NASA Technical Reports Server (NTRS)

This paper examines the question of cost, from the birth of a program to its conclusion, particularly from the point of view of large multi-center programs, and suggests how to avoid some of the traps and pitfalls. Emphasis is given to cost in the systems engineering process, but there is an inevitable overlap with program management. (These terms, systems engineering and program management, have never been clearly defined.) In these days of vast Federal budget deficits and increasing overseas competition, it is imperative that we get more for each research and development dollar. This is the only way we will retain our leadership in high technology and, in the long run, our way of life.

Hodge, John D.

1993-01-01

82

Rheology of petrolatum-paraffin oil mixtures: Applications to analogue modelling of geological processes  

NASA Astrophysics Data System (ADS)

Paraffins have been widely used in analogue modelling of geological processes. Petrolatum and paraffin oil are commonly used to lubricate model boundaries and to simulate weak layers. In this paper, we present rheological tests of petrolatum, paraffin oil and several homogeneous mixtures of the two. The results show that petrolatum and all petrolatum-paraffin oil mixtures are strain, strain rate and temperature dependent under typical experimental strain rates (10-3-10-1 s-1). For the same conditions, pure paraffin oil is a slightly temperature-dependent, linear, Newtonian fluid. All mixtures have yield stress and flow stress (strain softening) values that decrease with decreasing shear rate, and with increasing relative amounts of paraffin oil. The degree of strain rate dependence (shear thinning) also decreases with increasing paraffin oil content. Because these materials have rheologies that can be characterized and controlled, they are suitable for use in a large number of analogue model settings, either as a lubricant or to simulate weak layers. When used as a lubricant, mixtures with higher paraffin oil content should perform better than pure petrolatum.

Duarte, João C.; Schellart, Wouter P.; Cruden, Alexander R.

2014-06-01

83

Urban soil geochemistry in Athens, Greece: The importance of local geology in controlling the distribution of potentially harmful trace elements.  

PubMed

Understanding urban soil geochemistry is a challenging task because of the complicated layering of the urban landscape and the profound impact of large cities on the chemical dispersion of harmful trace elements. A systematic geochemical soil survey was performed across Greater Athens and Piraeus, Greece. Surface soil samples (0-10cm) were collected from 238 sampling sites on a regular 1×1km grid and were digested by a HNO3-HCl-HClO4-HF mixture. A combination of multivariate statistics and Geographical Information System approaches was applied for discriminating natural from anthropogenic sources using 4 major elements, 9 trace metals, and 2 metalloids. Based on these analyses the lack of heavy industry in Athens was demonstrated by the influence of geology on the local soil chemistry with this accounting for 49% of the variability in the major elements, as well as Cr, Ni, Co, and possibly As (median values of 102, 141, 16 and 24mg kg(-1) respectively). The contribution to soil chemistry of classical urban contaminants including Pb, Cu, Zn, Sn, Sb, and Cd (medians of 45, 39, 98, 3.6, 1.7 and 0.3mg kg(-1) respectively) was also observed; significant correlations were identified between concentrations and urbanization indicators, including vehicular traffic, urban land use, population density, and timing of urbanization. Analysis of soil heterogeneity and spatial variability of soil composition in the Greater Athens and Piraeus area provided a representation of the extent of anthropogenic modifications on natural element loadings. The concentrations of Ni, Cr, and As were relatively high compared to those in other cities around the world, and further investigation should characterize and evaluate their geochemical reactivity. PMID:24662205

Argyraki, Ariadne; Kelepertzis, Efstratios

2014-06-01

84

Report of the second meeting of the consultants on coupled processes associated with geological disposal of nuclear waste  

SciTech Connect

The second meeting of the Consultants on Coupled Processes Associated with Geological Disposal of Nuclear Waste occurred on January 15-16, 1985 at Lawrence Berkeley Laboratory (LBL). All the consultants were present except Dr. K. Kovari, who presented comments in writing afterward. This report contains a brief summary of the presentations and discussions from the meeting. The main points of the speakers' topics are briefly summarized in the report. Some points that emerged during the discussions of the presentations are included in the text related to the respective talks. These comments are grouped under the headings: Comments on Coupled Processes in Unsaturated Fractured Porous Media, Comments on Overview of Coupled Processes, Presentations by Consultants on Selected Topics of Current Interest in Coupled Processes, and Recommendations for Underground Field Tests with Applications to Three Geologic Environments.

Tsang, Chin-Fu; Mangold, D.C.

1985-09-01

85

Isotope and fluid inclusion studies of geological and hydrothermal processes, northern Peru  

SciTech Connect

Mineralization in the Hualgayoc district of northern Peru occurs in altered Miocene felsic intrusions and in mid-Cretaceous platform sedimentary rocks of the Goyllarisquizga, Inca, and Chulec formations. The ores occur both as stratiform and stratabound pyritiferous base-metal deposits (mantos), and as steeply dipping, sedimentary and intrusive rock-hosted base-metal veins. Igneous rocks in the district are affected by propylytic, sericitic-argillic, sericitic, potassic, and acid-sulfate alteration. K-Ar and Rb-Sr dating and geological evidence indicate multiple stages of intrusive activity and hydrothermal alteration, including close spatial emplacement of two or more separate Miocene magmatic-hydrothermal systems. K-Ar dates on sericite, hydrothermal biotite, and alunite indicate that the most important hydrothermal episodes in the district took place {approx}13.24 and 12.4 Ma. Other K-Ar dates on altered rocks in the district may reflect various amounts of resetting by the emplacement of the 9.05 {+-} 0.2 Ma Hualgayoc rhyodacite. A five-point Rb-Sr isochron for the San Miguel intrusion at Cerro Coymolache yields an age of 45 {+-} 3.4 Ma, which indicates much earlier magmatic activity in this area than recognized previously. Fluid inclusion and paragenetic studies reveal a clear temporal evolution of fluid temperature and chemistry in the San Agustin area at Hualgayoc. Gradually, ore formation shifted to precipitation of vein minerals in the brittle fractures as the mantos became less permeable and were sealed off. Vein formation continued from progressively cooler and more diluted fluids (down to {approx}150{degrees}C and 4.3 wt% NaCl equivalent) as the system waned. No evidence for phase separation is observed in the fluids until the very last paragenetic stage, which contributed no economic mineralization. 53 refs., 15 figs., 7 tabs.

MacFarlane, A.W. [Florida International Univ., Miami, FL (United States); Prol-Ledesma, R.M. [Cd. Universitaria, Coyoacan (Mexico); Conrad, M.E. [Lawrence Berkeley Lab., CA (United States)

1994-07-01

86

40 CFR 761.187 - Reporting importers and by persons generating PCBs in excluded manufacturing processes.  

Code of Federal Regulations, 2010 CFR

...importers and by persons generating PCBs in excluded manufacturing processes...TOXIC SUBSTANCES CONTROL ACT POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING...importers and by persons generating PCBs in excluded manufacturing...

2010-07-01

87

Processing and geologic analysis of conventional cores from well ER-20-6 No. 1, Nevada Test Site  

SciTech Connect

In 1996, Well Cluster ER-20-6 was drilled on Pahute Mesa in Area 20, in the northwestern corner of the Nevada Test Site (NTS). The three wells of the cluster are located from 166 to 296 meters (m) (544 to 971 feet [ft]) southwest of the site of the underground nuclear test code-named BULLION, conducted in 1990 in Emplacement Hole U-20bd. The well cluster was planned to be the site of a forced-gradient experiment designed to investigate radionuclide transport in groundwater. To obtain additional information on the occurrence of radionuclides, nature of fractures, and lithology, a portion of Well ER-20-6 No. 1, the hole closest to the explosion cavity, was cored for later analysis. Bechtel Nevada (BN) geologists originally prepared the geologic interpretation of the Well Cluster ER-20-6 site and documented the geology of each well in the cluster. However, the cores from Well ER-20-6 No. 1 were not accessible at the time of that work. As the forced-gradient experiment and other radio nuclide migration studies associated with the well cluster progressed, it was deemed appropriate to open the cores, describe the geology, and re-package the core for long-term air-tight storage. This report documents and describes the processing, geologic analysis, and preservation of the conventional cores from Well ER20-6 No. 1.

Prothro, L.B., Townsend, M.J.; Drellack, S.L. Jr. [and others

1997-09-01

88

The southeastern border of the Upper Rhine Graben: a 3D geological model and its importance for tectonics and groundwater flow  

Microsoft Academic Search

A 3D geological model of the area east of Basel on the southeastern border of the Upper Rhine Graben, consisting of 47 faults and six stratigraphic horizons relevant for groundwater flow, was developed using borehole data, geological maps, geological cross sections, and outcrop data. This model provides new insight into the discussions about the kinematics of the area between the

Ina Spottke; Eric Zechner; Peter Huggenberger

2005-01-01

89

Geologic mapping of tectonic planets  

Microsoft Academic Search

Geological analysis of planets typically begins with the construction of a geologic map of the planets’ surfaces using remote data sets. Geologic maps provide the basis for interpretations of geologic histories, which in turn provide critical relations for understanding the range of processes that contributed to the evolution. Because geologic mapping should ultimately lead to the discovery of the types

Vicki L. Hansen

2000-01-01

90

Influence in the Policy Making Process: the Rise of Economics at the Expense of Geology  

NASA Astrophysics Data System (ADS)

Scientific influence in resource policy making reached a zenith in the early 1970s during the legislative monopoly in the United States Congress that produced command and control regulatory protection policies. This congressional consensus began in 1879 with legislation producing the U.S. Geological Survey. Other scientific agencies followed. The Congresses of the first half of the 20th century merely strengthened the influence of science in policy outcomes that was present in the earliest congressional debates. What then happened at the turn of the 21st century when representatives in the administration frequently dismissed sound science in their policy deliberations? Policy monopolies arise from agreement in principle, and alternately decline as rival ideas gain hold in policy space. The science policy monopoly began to face competition from economics when cost benefit analysis was introduced into political parlance in 1936, again in the 1950s as a successful blocking tactic by the minority in opposition to western dams, and in 1961 when systems analysis was introduced to the Department of Defense under Robert McNamara. As businessmen replaced farmers as the modal profession of legislators, the language of politics increasingly contained economic terms and concepts. A ternary diagram and a budget simplex have the same shape, but have different theoretical meanings and imply different processes. Policy consensus is not dissimilar to a mineral phase diagram, with boundary conditions marked by election magnitudes and majority parties. The 1980 elections brought economic principles into all aspects of government decision-making, with a particular long-term interest in reducing the size and scope of government. Since then the shift in policy jargon from science to economics has been incremental. With the 1994 Republican legislative majority, scientists, their programs, and the funds required to maintain data collection projects became targets. The Conservative Consensus resulting from the 2000 elections has disregarded and even ridiculed scientific experts, their analyses, and their data. The first step in rebuilding an effective policy consensus based on sound science is recognizing the phase transition that privileges conservative policy solutions which minimize science and elevate economic principles.

McCurdy, K. M.

2007-12-01

91

The geological processes time scale of the Ingozersky block TTG complex (Kola Peninsula)  

NASA Astrophysics Data System (ADS)

Ingozersky block located in the Tersky Terrane of the Kola Peninsula is composed of Archean gneisses and granitoids [1; 5; 8]. The Archaean basement complexes on the regional geological maps have called tonalite-trondemit-gneisses (TTG) complexes [6]. In the previous studies [1; 3; 4; 5; 7] within Ingozersky block the following types of rocks were established: biotite, biotite-amphibole, amphibole-biotite gneisses, granites, granodiorites and pegmatites [2]. In the rocks of the complex following corresponding sequence of endogenous processes observed (based on [5]): stage 1 - the biotitic gneisses formation; 2 - the introduction of dikes of basic rocks; 3 phase - deformation and foliation; 4 stage - implementation bodies of granite and migmatization; 5 stage - implementation of large pegmatite bodies; stage 6 - the formation of differently pegmatite and granite veins of low power, with and without garnet; stage 7 - quartz veins. Previous U-Pb isotopic dating of the samples was done for biotite gneisses, amphibole-biotite gneisses and biotite-amphibole gneisses. Thus, some Sm-Nd TDM ages are 3613 Ma - biotite gnesses, 2596 Ma - amphibole-biotite gnesses and 3493 Ma biotite-amphibole gneisses.. U-Pb ages of the metamorphism processes in the TTG complex are obtained: 2697±9 Ma - for the biotite gneiss, 2725±2 and 2667±7 Ma - for the amphibole-biotite gneisses, and 2727±5 Ma for the biotite-amphibole gneisses. The age defined for the biotite gneisses by using single zircon dating to be about 3149±46 Ma corresponds to the time of the gneisses protolith formation. The purpose of these studies is the age establishing of granite and pegmatite bodies emplacement and finding a geological processes time scale of the Ingozerskom block. Preliminary U-Pb isotopic dating of zircon and other accessory minerals were held for granites - 2615±8 Ma, migmatites - 2549±30 Ma and veined granites - 1644±7 Ma. As a result of the isotope U-Pb dating of the different Ingozerskogo TTG complex rocks, the following age-formation stages are determined: protolith of the biotite gneisses - 3149±46 Ma; metamorphism, deformation of rocks, foliation - 2727±5 - 2725±2 - 2697±9 - 2667±7 Ma, granite bodies formation - 2615±8 Ma and biotite gneisses migmatization - 2549±30 Ma, formation of different pegmatite and granite veins -1644±7 Ma. Author are grateful to Akad. Mitrofanov F.P. and Bayanova T.B. for the consultations. The work is supported by RFBR 12-05-31063, 11-05-00570. 1.Batieva I.D., Belkov I.V. Granitoidnie formacii Kolskogo poluostrova. // Ocgerki po petrologiy, mineralogiy i metallogeniy Kolskogo poluostrova. L.: Nauka. 1968. p. 5-143. (in russian) 2. Belkov I.V., Zagorodny V.G., Predovsky A.A. et al. Stratigraficheskoe raschlenenie i korrelyacia dokembria severo-vostochoi chasty Baltiyskogo shita. L.: Nauka. 1971. p. 141-150. (in russian) 3. Docembriskaya tektonica severo-vostochoi chasty Baltiyskogo shita (Ob'asnitelnaya zapiska k tektonicheskoi karte severo-vostochoi chasty Baltiyskogo shita 1:500000) / ed.: F.P.Mitrofanov. Apatity: KFAN SSSR. 1992. 112 P. (in russian) 4. Zagorodny V.G., Radchenko A.T. Tectonika i glubinnoe stroenie severo-vostochoi chasty Baltiyskogo shita. Apatity: KFA SSSR. 1978. p. 3-12. (in russian) 5. Kozlov N.E., Sorohtin N.O., Glaznev V.N. et al. Geologia Arhea Baltiskogo shita. S.Pb.: Nauka. 2006. 329 p. (in russian) 6. Mitrofanov F.P. Sovremennie problemy i nekotorie resheniya dokembriskoy geologii kratonov. (2001) Litosphera.2001. V 1. P. 5-14. (in russian) 7. Ob'asnitelnaya zapiska k geologicheskoy karte severo-vostochoi chasty Baltiyskogo shita 1:500000 / ed.: F.P.Mitrofanov. Apatity: KFAN SSSR. 1994. 95 P. (in russian) 8. Haritonov L.Y. Structura i stratigraphia karelid vostoka Baltiskogo shita. M.: Nedra. 1966. 354 P. (in russian)

Nitkina, Elena

2013-04-01

92

Process-based approach to CO2 leakage detection by vadose zone gas monitoring at geologic CO2 storage sites  

NASA Astrophysics Data System (ADS)

A critical issue for geologic carbon sequestration is the ability to detect CO2 in the vadose zone. Here we present a new process-based approach to identify CO2 that has leaked from deep geologic storage reservoirs into the shallow subsurface. Whereas current CO2 concentration-based methods require years of background measurements to quantify variability of natural vadose zone CO2, this new approach examines chemical relationships between vadose zone N2, O2, CO2, and CH4 to promptly distinguish a leakage signal from natural vadose zone CO2. The method uses sequential inspection of the following gas concentration relationships: 1) O2 versus CO2 to distinguish in-situ vadose zone background processes (biologic respiration, methane oxidation, and CO2 dissolution) from exogenous deep leakage input, 2) CO2 versus N2 to further distinguish dissolution of CO2 from exogenous deep leakage input, and 3) CO2 versus N2/O2 to assess the degree respiration, CH4 oxidation and atmospheric mixing/dilution occurring in the system. The approach was developed at a natural CO2-rich control site and successfully applied at an engineered site where deep gases migrated into the vadose zone. The ability to identify gas leakage into the vadose zone without the need for background measurements could decrease uncertainty in leakage detection and expedite implementation of future geologic CO2 storage projects.

Romanak, K. D.; Bennett, P. C.; Yang, Changbing; Hovorka, Susan D.

2012-08-01

93

The Mari Rosa late Hercynian Sb-Au deposit, western Spain Geology and geochemistry of the mineralizing processes  

NASA Astrophysics Data System (ADS)

The central Iberian zone of the Hesperian Massif hosts a series of late Hercynian vein-type Sb deposits. One of them is the Mari Rosa mineralization, hosted by metagreywackes and slates of the Schist-Greywacke Complex (Upper Precambrian). The mineralization is characterized by a complex paragenesis comprising three hydrothermal stages: stage H1?arsenopyrite-(pyrite); stage H2?stibnite-gold; and stage H3?pyrite-pyrrhotite-galena-sphalerite-chalcopyrite-tetrahedrite-boulangerite-stibnite. Of these only the second episode was of importance and gave rise to the main mineralized bodies of the deposit. Hydrothermal alteration consists of a mild sericitization, chloritization and carbonatization of the metasedimentary rocks around the veins. Chemical changes in the hydrothermal halos include a remarkable increase in the ratio K2O/Na2O, and a decrease in the ratio SiO2/volatiles, together with a sharp increase in Sb, Mo, Au and N. Fluids associated with ore deposition lie in the H2O-NaCl-CO2-CH4-N2 compositional system. These fluids evolved, progressively cooling, from initial circulaion temperatures close to 400°C in the early stage (H1) to temperatures of approximately 150 °C in the late one (H3). Fluid composition evolution was characterized by a progressive increase in the bulk water content of the fluids and with an increase in the relative proportion of N2 with respect to CH4 and CO2 in the volatile fraction. Massive stibnite deposition resulted from a boiling process developed at 300 °C and 0.9 1 Kb at a depth of 4 5 km. Geological, geochemical and fluid inclusion evidence suggest that the intrusion of the Alburquerque batholith (late Hercynian S-type granitoids) triggered hydrothermal activity leading to the transport and deposition of Sb and Au in Mari Rosa.

Ortega, L.; Oyarúun, R.; Gallego, M.

1996-03-01

94

Quaternary geology and geomorphology of the Sacramento-San Joaquin Delta, California: evolution and processes  

NASA Astrophysics Data System (ADS)

The Sacramento-San Joaquin Delta (~1,400 km2) is a combination of tidal marsh, islands and agricultural lands at the confluence of the Sacramento and the San Joaquin Rivers, in northern California. Most of the Delta islands are now 3 to 8 m below sea-level and must be protected by levees from inundation. Because of the Delta's crucial role in conveying fresh water to the State, levee failures can cause substantial economic loss by disrupting this supply. Understanding the evolution of the Delta is fundamental to assess the vulnerability of the Delta islands to seismically-induced levee failure. The modern Delta is a young geological feature that began forming during the middle Holocene. Preceding versions of the Delta hosted a variety of depositional environments as sea level fluctuated, responding to climatically-controlled changes. The rising sea reached the Delta about 8,000 years ago, and modern deltaic evolution continued into Holocene time until present. More accurate stratigraphic studies incorporating depositional ages are required to i) better understand the late Quaternary evolution of the Delta, ii) trace the base of Holocene deposits, iii) identify potentially active faults, and iv) evaluate liquefaction hazard for the Delta . This study uses the large amount of data available on the Delta (collected by the California Department of Water Resources and others during the past 30 years) and merges them into a unified dataset. We have produced a database that includes historic and surficial maps, aerial photographs, boreholes, and CPT data, for the purpose of clarifying the nature of the Quaternary deposits and the evolution of the Late Quaternary Delta. Additionally, we have identified recently discovered Pleistocene tephra as the Rockland ash, ~0.575 Ma, and the Loleta ash, ~0.40-0.37 Ma, which have improved stratigraphic correlations and assessment of subsidence rates. Delta sediments include sequences of glacial and interglacial deposits. Borehole logs reveal sequences of incision and backfilling corresponding to major climatic fluctuations: incised channels, sand-filling channels, gravel alluvial fans and eolian dunes during glacial periods, and fine-grained alluvial floodplains, mud flats deposits, marshes and peat during warmer interglacials. The evolution of the Delta is likely the result of three processes: subsidence (based on tephra ages, between ~0.004 cm/yr and 0.007 cm/yr in the Northern Delta, ~0.01 cm/yr in the central Delta, ~0.06 cm/yr in the Eastern Delta), compaction due to organic soil oxidation (3.6-6.1 cm/yr), and tectonic control. The thickness of the organic soils (>20 m) suggests that the Holocene sea-level rise was the major factor controlling the Delta's morphology before agricultural drainage began in the 1850's. Because the patterns suggest that sea-level rise was the major cause of changes in the Delta, it is likely that once the organic soil is all oxidized by anthropogenic processes within a few centuries, the major controlling factor will become anthropogenic sea-level rise.

Gatti, E.; Maier, K. L.; Holzer, T. L.; Knudsen, K. L.; Olson, H.; Pagenknopp, M.; Ponti, D. J.; Rosa, C.; Tinsley, J. C.; Wan, E.

2013-12-01

95

Digital processing of orbital radar data to enhance geologic structure - Examples from the Canadian Shield  

NASA Technical Reports Server (NTRS)

Various digital enhancement techniques for SAR are compared using SIR-B and Seasat images of the Canadian Shield. The three best methods for enhancing geological structure were found to be: (1) a simple linear contrast stretch; (2) a mean or median low-pass filter to reduce speckle prior to edge enhancement or a K nearest-neighbor average to cosmetically reduce speckle; and (3) a modification of the Moore-Waltz (1983) technique. Three look directions were coregistered and several means of data display were investigated as means of compensating for radar azimuth biasing.

Masuoka, Penny M.; Harris, Jeff; Lowman, Paul D., Jr.; Blodget, Herbert W.

1988-01-01

96

Genesis of karren in Kentucky Lake, Tennessee: Interaction of geologic structure, weathering processes, and bioerosion  

SciTech Connect

While karst features formed along marine coastlines are commonly reported, shoreline karst features produced within lacustrine systems have received little attention. The shoreline of Bond Island'' in Kentucky Lake has evolved a distinctive karren geomorphology not recognized elsewhere in the lake. The karren consist of well-developed clint and grike topography, trench formation, solution pits, flutes, and runnels, and pit and tunnel development. Two processes are responsible for the karren. First, freshwater dissolution and wave action on structurally fractured Decatur Limestone (Silurian) mechanically and chemically weaken the entire exposed surface. Second, a seasonal cycle of winter freeze-thaw and frost wedging followed by spring bioerosion overprints the first set of processes. Bioerosion by chemical dissolution involving a complex association of predominantly chironomids, algae, fungi, and bryozoa results in preferential dissolution along joints, stylolites, and bedding planes to form shallow spindle-shaped solution pits over the entire surface and sides of the karren. The solution pits average 1 cm length by 0.4 cm depth densely covering rock surfaces. This study suggests that seasonal bioerosion may constitute a more important geomorphic factor in lacustrine systems than previously recognized.

Gibson, M.A.; Smith, W.L. (Univ. of Tennessee, Martin, TN (United States))

1993-03-01

97

Quaternary geology and sedimentary processes in the vicinity of Six Mile Reef, eastern Long Island Sound  

USGS Publications Warehouse

Six Mile Reef, a sandy, 22-m-high shoal trending east-west and located about 7.8 km off the Connecticut coast, has a core of postglacial marine deltaic deposits mantled by tidally reworked modern sediments. Sedimentary environments off the eastern end of the shoal are characterized by processes associated with long-term erosion or nondeposition, a mobile-sediment-limited seafloor armored by gravelly sand, and scattered elongate fields of barchanoid sand waves. The barchanoid waves reach amplitudes of 20 m, are concave westward, and occur in individual and coalesced forms that become progressively more complex westward. The seafloor on and adjacent to the shoal is characterized by processes associated with coarse bedload transport and covered primarily with asymmetrical transverse sand waves. The transverse waves exceed 8 m in amplitude, have slip faces predominantly oriented to the west and southwest, and have straight, slightly sinuous, and curved crests. Megaripples, which mimic the asymmetry of the sand waves, are commonly present on stoss slopes and in troughs; current ripples are ubiquitous. The amplitude and abundance of large bedforms decrease markedly westward of Six Mile Reef. The seabed there is covered with small, degraded ripples, reflecting lower-energy environments and processes associated with sorting and reworking of seafloor sediments. Megaripples and current ripples on the sand waves suggest that transport is active and that the bedforms are propagating under the present hydraulic regime. Net bedload sediment transport is primarily to the west, as evidenced by textural trends of surficial sediments, orientation of the barchanoid waves, and asymmetry of the transverse waves and of the scour marks around bedrock outcrops, boulders, and shipwrecks. One exception occurs at the western tip of the shoal, where sand-wave morphology indicates long-term eastward transport, suggesting that countercurrents in this area shape the shoal and are important to its maintenance.

Poppe, L.J.; Williams, S.J.; Moser, M.S.; Forfinski, N.A.; Stewart, H.F.; Doran, E.F.

2008-01-01

98

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.

99

Geological Survey research 1976  

USGS Publications Warehouse

This U.S. Geological Survey activities report includes a summary of recent (1976 fiscal year) scientific and economic results accompanied by a list of geologic and hydrologic investigations in progress and a report on the status of topographic mapping. The summary of results includes: (1) Mineral resources, Water resources, (2) Engineering geology and hydrology, (3) Regional geology, (4) Principles and processes, (5) Laboratory and field methods, (6) Topographic surveys and mapping, (7) Management of resources on public lands, (8) Land information and analysis, and (9) Investigations in other countries. Also included are lists of cooperating agencies and Geological Survey offices. (Woodard-USGS)

Geological Survey (U.S.)

1976-01-01

100

Geological Survey research 1978  

USGS Publications Warehouse

This U.S. Geological Survey activities report includes a summary of 1978 fiscal year scientific and economic results accompanied by a list of geologic and hydrologic investigations in progress and a report on the status of topographic mapping. The summary of results includes: (1) Mineral and water resources, (2) Engineering geology and hydrology, (3) Regional geology, (4) Principles and processes, (5) Laboratory and field methods, (6) Topographic surveys and mapping, (7) Management of resources on public lands, (8) Land information and analysis, and (9) Investigations in other countries. Also included are lists of cooperating agencies and Geological Survey offices. (Woodard-USGS)

1978-01-01

101

Using Snow to Teach Geology.  

ERIC Educational Resources Information Center

A lesson plan, directed at middle school students and older, describes using snow to study the geological processes of solidification of molten material, sedimentation, and metamorphosis. Provides background information on these geological processes. (MCO)

Roth, Charles

1991-01-01

102

Preliminary paper - Integrated control process for the development of the mined geologic disposal system  

SciTech Connect

The US Department of Energy (DOE) Order 430.1, Life Cycle Asset Management, begins to focus DOE Programs and Projects on the total system life cycle instead of looking at project execution or operation as individual components. As DOE begins to implement this order, the DOE Management and Operating contractors must develop a process to control not only the contract baseline but also the overall life cycle baseline. This paper presents an integrated process that is currently being developed on the Yucca Mountain Project for DOE. The process integrates the current contract/project baseline management process with the management control process for design and the configuration management change control process.

Daniel, Russell B.; Harbert, Kevin R.; Calloway, David E.

1997-11-26

103

Conduct of Geologic Field Work During Planetary Exploration: Why Geology Matters  

NASA Technical Reports Server (NTRS)

The science of field geology is the investigative process of determining the distribution of rock units and structures on a planet s surface, and it is the first order data set that informs all subsequent studies of a planet, such as geochemistry, geochronology, geophysics or remote sensing. These allied sciences, as important as they are, derive the basis of their understanding from the knowledge of the geology of a given location. When we go back to the Moon, and on to Mars, the surface systems we deploy will need to support the conduct of field geology if these endeavors are to be scientifically useful. This lecture will consider what field geology is about - why it s important, how we do it, how the conduct of field geology informs many other sciences, and how it will affect the design of surface systems and implementation of operations in the future.

Eppler, Dean B.

2010-01-01

104

Redesigning and Transforming: A Case Study of the Role of Semiotic Import in Early Composing Processes  

ERIC Educational Resources Information Center

In this article, I explore the role of semiotic import (Van Leeuwen, 2005) in the composing processes of three bilingual students (six to seven years old) emerging as writers of English. Using social semiotic (Van Leeuwen, 2005) and design (New London Group, 2000) frameworks, I trace a qualitative "micro-history" of how the students imported…

Ranker, Jason

2009-01-01

105

Significant achievements in the planetary geology program, 1981  

NASA Technical Reports Server (NTRS)

Recent developments in planetology research are summarized. Important developments are summarized in topics ranging from solar system evolution, comparative planetology, and geologic processes, to techniques and instrument development for future exploration.

Mouginis-Mark, P. J.

1982-01-01

106

Significant achievements in the planetary geology program, 1980  

NASA Technical Reports Server (NTRS)

Recent developments in planetology research as reported at the 1980 NASA Planetology Program Principal Investigators meeting are summarized. Important developments are summarized in topics ranging from solar system evolution and comparative planetology to geologic processes active on other planetary bodies.

Holt, H. E. (editor)

1980-01-01

107

Onshore Quaternary geological surveys in the 21st century—a perspective from the British Geological Survey  

Microsoft Academic Search

At the turn of the century the British Geological Survey has embarked on a major programme to construct a 3-dimensional geological model of the UK. The reassessment of methodologies used to investigate Quaternary deposits and processes forms an important part of this programme. Surveys of user requirements indicate that the collation of new data and the generation of new output

Andrew A McMillan

2002-01-01

108

USGS: Geology in the Parks  

NSDL National Science Digital Library

The US Geological Survey Geology in the Parks Web site is a cooperative project of the USGS Western Earth Surface Processes Team and the National Park Service. This extensive site covers geologic maps, plate tectonics, rocks and minerals, geologic time, US geologic provinces, park geology of the Mojave, Sunset Crater, Lake Mead, North Cascades, Death Valley, Yosemite National Park, and much more. Descriptions, graphics, photographs, and animations all contribute to this informative and interesting Web site making it a one stop, all encompassing, resource for everything geology and US national park related.

109

Process Consistency in Models: the Importance of System Signatures, Expert Knowledge and Process Complexity  

NASA Astrophysics Data System (ADS)

Hydrological models are frequently characterized by what is often considered to be adequate calibration performances. In many cases, however, these models experience a substantial uncertainty and performance decrease in validation periods, thus resulting in poor predictive power. Besides the likely presence of data errors, this observation can point towards wrong or insufficient representations of the underlying processes and their heterogeneity. In other words, right results are generated for the wrong reasons. Thus ways are sought to increase model consistency and to thereby satisfy the contrasting priorities of the need a) to increase model complexity and b) to limit model equifinality. In this study a stepwise model development approach is chosen to test the value of an exhaustive and systematic combined use of hydrological signatures, expert knowledge and readily available, yet anecdotal and rarely exploited, hydrological information for increasing model consistency towards generating the right answer for the right reasons. A simple 3-box, 7 parameter, conceptual HBV-type model, constrained by 4 calibration objective functions was able to adequately reproduce the hydrograph with comparatively high values for the 4 objective functions in the 5-year calibration period. However, closer inspection of the results showed a dramatic decrease of model performance in the 5-year validation period. In addition, assessing the model's skill to reproduce a range of 20 hydrological signatures including, amongst others, the flow duration curve, the autocorrelation function and the rising limb density, showed that it could not adequately reproduce the vast majority of these signatures, indicating a lack of model consistency. Subsequently model complexity was increased in a stepwise way to allow for more process heterogeneity. To limit model equifinality, increase in complexity was counter-balanced by a stepwise application of "realism constraints", inferred from expert knowledge (e.g. unsaturated storage capacity of hillslopes should exceed the one of wetlands) and anecdotal hydrological information (e.g. long-term estimates of actual evaporation obtained from the Budyko framework and long-term estimates of baseflow contribution) to ensure that the model is well behaved with respect to the modeller's perception of the system. A total of 11 model set-ups with increased complexity and an increased number of realism constraints was tested. It could be shown that in spite of largely unchanged calibration performance, compared to the simplest set-up, the most complex model set-up (12 parameters, 8 constraints) exhibited significantly increased performance in the validation period while uncertainty did not increase. In addition, the most complex model was characterized by a substantially increased skill to reproduce all 20 signatures, indicating a more suitable representation of the system. The results suggest that a model, "well" constrained by 4 calibration objective functions may still be an inadequate representation of the system and that increasing model complexity, if counter-balanced by realism constraints, can indeed increase predictive performance of a model and its skill to reproduce a range of hydrological signatures, but that it does not necessarily result in increased uncertainty. The results also strongly illustrate the need to move away from automated model calibration towards a more general expert-knowledge driven strategy of constraining models if a certain level of model consistency is to be achieved.

Hrachowitz, Markus; Fovet, Ophelie; Ruiz, Laurent; Gascuel-Odoux, Chantal; Savenije, Hubert

2014-05-01

110

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

111

Dynamics of present-day geological processes from remotely sensed data  

NASA Astrophysics Data System (ADS)

Remotely sensed data on the dynamics of present-day exogenous and endogenous processes occurring at different depths and with different intensity and manifestations are discussed. Attention is given to the processes of continental-sediment accumulation at the Tedzhen and Murgab River deltas and the Amu-Daria River bed, deformation processes occurring in the Pamir-Alai region, and the deep-lying interactions of the Iranian and Turan platforms. It is noted that the presence of high-degree correlations among the lineament fields of the individual subregions of the Pamir-Alai region, the Gissar-Alai region, and the region of northern Pamir suggests that these regions belong to a single elongated dynamic zone.

Kats, Ia. G.; Poletaev, A. I.; Rumiantseva, E. F.; Tevelev, A. V.

112

The Large Impact Process Inferred from the Geology of Lunar Multiring Basins  

NASA Technical Reports Server (NTRS)

The study of the geology of multiring impact basins on the Moon over the past ten years has given us a rudimentary understanding of how these large structures have formed and evolved on the Moon and other bodies. Two-ring basins on the Moon begin to form at diameters of about 300 km; the transition diameter at which more than two rings appear is uncertain, but it appears to be between 400 and 500 km in diameter. Inner rings tend to be made up of clusters or aligned segments of massifs and are arranged into a crudely concentric pattern; scarp-like elements may or may not be present. Outer rings are much more scarp-like and massifs are rare to absent. Basins display textured deposits, interpreted as ejecta, extending roughly an apparent basin radius exterior to the main topographic rim. Ejecta may have various morphologies, ranging from wormy and hummocky deposits to knobby surfaces; the causes of these variations are not known, but may be related to the energy regime in which the ejecta are deposited. Outside the limits of the textured ejecta are found both fields of satellitic craters (secondaries) and light plains deposits. Impact melt sheets are observed on the floors of relatively unflooded basins. Samples of impact melts from lunar basins have basaltic major-element chemistry, characterized by K, rare-earth elements (REE), P, and other trace elements of varying concentration (KREEP); ages are between 3.8 and 3.9 Ga. These lithologies cannot be produced through the fusion of known pristine (plutonic) rock types, suggesting the occurrence of unknown lithologies within the Moon. These melts were probably generated at middle to lower crustal levels. Ejecta compositions, preservation of pre-basin topography, and deposit morphologies all indicate that the excavation cavity of multiring basins is between about 0.4 and 0.6 times the diameter of the apparent crater diameter. Basin depths of excavation can be inferred from the composition of basin ejecta. A variety of mechanisms has been proposed to account for the formation of basin rings but none of them are entirely plausible. Mechanisms can be divided into two broad groups: (1) forcible uplift due to fluidization of the target; (2) concentric, brittle, fracturing and failure of the target, on regional (megaterraces) to global scales (lithospheric fracturing). Most basin rings are spaced at a constant factor on all planets. Evidence supports divergent ringforming models, so it may be that the ring-locating mechanism differs from the ring-forming mechanism. Thus, large-scale crustal foundering (megaterracing) could occur along concentric zones of weakness created by some type of resonant wave mechanism (fluidization and uplift); such immediate crustal adjustment could then be followed by long-term adjustment of the fractured lithosphere.

Spudis, Paul D.

1994-01-01

113

Complex Process Couplings Related to Deep Geologic Sequestration and Energy Recovery (Invited)  

NASA Astrophysics Data System (ADS)

Fluids in the shallow crust exert important controls on a wide spectrum of natural and engineered phenomena. The complex interaction of stress and particularly that of chemistry exhibit important feedbacks which influence the evolution of the mechanical and transport properties of rocks. These feedbacks in turn relate crucially to the subsurface recovery of hydrocarbons from the full spectrum of conventional through unconventional reservoirs, to the recovery of hydrothermal and non-hydrothermal geothermal resources, to the secure and enduring sequestration of energy by-products, and to the earthquake cycle, for example. Enigmatic interactions between stress and chemistry in mediating the evolution of permeability and strength in natural and engineered systems are explored - as relevant to high-carbon through low-carbon energy systems. Examples are selected to illustrate the significance of these interactions in controlling the response of hydrocarbon and geothermal reservoirs, fracture treatments, radioactive waste disposal and in the response of faults.

Elsworth, D.

2009-12-01

114

Results From an International Simulation Study on Couples Thermal, Hydrological, and Mechanical (THM) Processes Near Geological Nuclear Waste Repositories  

SciTech Connect

As part of the ongoing international DECOVALEX project, four research teams used five different models to simulate coupled thermal, hydrological, and mechanical (THM) processes near waste emplacement drifts of geological nuclear waste repositories. The simulations were conducted for two generic repository types, one with open and the other with back-filled repository drifts, under higher and lower postclosure temperatures, respectively. In the completed first model inception phase of the project, a good agreement was achieved between the research teams in calculating THM responses for both repository types, although some disagreement in hydrological responses is currently being resolved. In particular, good agreement in the basic thermal-mechanical responses was achieved for both repository types, even though some teams used relatively simplified thermal-elastic heat-conduction models that neglected complex near-field thermal-hydrological processes. The good agreement between the complex and simplified process models indicates that the basic thermal-mechanical responses can be predicted with a relatively high confidence level.

J. Rutqvist; D. Barr; J.T. Birkholzer; M. Chijimatsu; O. Kolditz; Q. Liu; Y. Oda; W. Wang; C. Zhang

2006-08-02

115

Fluid flow in the earth's crust plays an important role in a number of geologic processes. In carbonate reservoirs, fluid  

E-print Network

in the fractured media results in changes in the pore pressure and consequently causes changes in the effective demon- strated that seismic waves can be used to monitor changes in oil or gas reservoirs as a function of fluids is accompanied by substantial change in the pore pressure field. As fluids drain, pore pressure

116

Collaborative web-based annotation of video footage of deep-sea life, ecosystems and geological processes  

NASA Astrophysics Data System (ADS)

More and more seagoing scientific expeditions use video-controlled research platforms such as Remote Operating Vehicles (ROV), Autonomous Underwater Vehicles (AUV), and towed camera systems. These produce many hours of video material which contains detailed and scientifically highly valuable footage of the biological, chemical, geological, and physical aspects of the oceans. Many of the videos contain unique observations of unknown life-forms which are rare, and which cannot be sampled and studied otherwise. To make such video material online accessible and to create a collaborative annotation environment the "Video Annotation and processing platform" (V-App) was developed. A first solely web-based installation for ROV videos is setup at the German Center for Marine Environmental Sciences (available at http://videolib.marum.de). It allows users to search and watch videos with a standard web browser based on the HTML5 standard. Moreover, V-App implements social web technologies allowing a distributed world-wide scientific community to collaboratively annotate videos anywhere at any time. It has several features fully implemented among which are: • User login system for fine grained permission and access control • Video watching • Video search using keywords, geographic position, depth and time range and any combination thereof • Video annotation organised in themes (tracks) such as biology and geology among others in standard or full screen mode • Annotation keyword management: Administrative users can add, delete, and update single keywords for annotation or upload sets of keywords from Excel-sheets • Download of products for scientific use This unique web application system helps making costly ROV videos online available (estimated cost range between 5.000 - 10.000 Euros per hour depending on the combination of ship and ROV). Moreover, with this system each expert annotation adds instantaneous available and valuable knowledge to otherwise uncharted material.

Kottmann, R.; Ratmeyer, V.; Pop Ristov, A.; Boetius, A.

2012-04-01

117

Geological Survey research 1981  

USGS Publications Warehouse

This U.S. Geological Survey activities report includes a summary of 1981 fiscal year scientific and economic results accompanied by a list of geologic, hydrologic, and cartographic investigations in progress. The summary of results includes: (1) Mineral, (2) Water resources, (3) Engineering geology and hydrology, (4) Regional geology, (5) Principles and processes, (6) Laboratory and field methods, (7) Topographic surveys and mapping, (8) Management of resources on public lands, (9) Land information and analysis, and (10) Investigations in other countries. Also included are lists of investigations in progress. (USGS)

1982-01-01

118

Mathematical Geology.  

ERIC Educational Resources Information Center

Mathematical techniques used to solve geological problems are briefly discussed (including comments on use of geostatistics). Highlights of conferences/meetings and conference papers in mathematical geology are also provided. (JN)

Jones, Thomas A.

1983-01-01

119

Layer Cake Geology  

NSDL National Science Digital Library

This classroom activity uses a cake to demonstrate geologic processes and introduce geologic terms. Students will learn how folds and faults occur, recognize the difference in behavior between brittle and ductile rocks, and attempt to predict structures likely to result from application of various forces to layered rocks. They will also attempt to interpret 'core samples' to determine subsurface rock structure.

Wagner, John

120

Earth Sciences Geology Option  

E-print Network

courses, core Earth Sciences courses, and focused coursework in the option. A graduation checklistEarth Sciences with Geology Option Geological sciences focus on understanding the Earth, from its composition and internal structure to its history and the processes that shape its surface. Our planet

Kurapov, Alexander

121

Radiometric Dating in Geology.  

ERIC Educational Resources Information Center

Described are several aspects and methods of quantitatively measuring geologic time using a constant-rate natural process of radioactive decay. Topics include half lives and decay constants, radiogenic growth, potassium-argon dating, rubidium-strontium dating, and the role of geochronology in support of geological exploration. (DS)

Pankhurst, R. J.

1980-01-01

122

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

123

Insights into Titan's geology and hydrology based on enhanced image processing of Cassini RADAR data  

NASA Astrophysics Data System (ADS)

The Cassini Synthetic Aperture Radar has been acquiring images of Titan's surface since October 2004. To date, 59% of Titan's surface has been imaged by radar, with significant regions imaged more than once. Radar data suffer from speckle noise hindering interpretation of small-scale features and comparison of reimaged regions for change detection. We present here a new image analysis technique that combines a denoising algorithm with mapping and quantitative measurements that greatly enhance the utility of the data and offers previously unattainable insights. After validating the technique, we demonstrate the potential improvement in understanding of surface processes on Titan and defining global mapping units, focusing on specific landforms including lakes, dunes, mountains, and fluvial features. Lake shorelines are delineated with greater accuracy. Previously unrecognized dissection by fluvial channels emerges beneath shallow methane cover. Dune wavelengths and interdune extents are more precisely measured. A significant refinement in producing digital elevation models is shown. Interactions of fluvial and aeolian processes with topographic relief is more precisely observed and understood than previously. Benches in bathymetry are observed in northern sea Ligeia Mare. Submerged valleys show similar depth suggesting that they are equilibrated with marine benches. These new observations suggest a liquid level increase in the northern sea, which may be due to changes on seasonal or longer timescales.

Lucas, Antoine; Aharonson, Oded; Deledalle, Charles; Hayes, Alexander G.; Kirk, Randolph; Howington-Kraus, Elpitha

2014-10-01

124

Geological Time  

NSDL National Science Digital Library

"Why do engineers need to know about geologic time?" That question is answered in this resource from the University of Saskatchewan's Department of Civil and Geological Engineering. Provided here is a discussion of the concepts of geological time; relative dating methods, such as correlation; and absolute dating methods, such as radiometric methods. Diagrams and charts are included to demonstrate these complex concepts.

2008-04-17

125

Geological SciencesGeological Sciences Geological EngineeringGeological Engineering  

E-print Network

Geological Engineering Applied Science Faculty Geology is the study of the Earth, its rocks, minerals Faculty and the Applied Science (Engineering) Faculty with various career path options. Geological engineers apply earth science principles to find and extract the world's energy and mineral wealth, to help

Ellis, Randy

126

Polar boundary layer processes: Important factors for investigating biogeochemistry and climate  

NASA Astrophysics Data System (ADS)

Ice at the Interface: Atmosphere-Ice-Ocean Boundary Layer Processes and Their Role in Polar Change; Boulder, Colorado, 25-27 June 2012 The atmosphere-ocean boundary layer in which sea ice resides includes many complex physical processes requiring a more realistic treatment in climate models, particularly as models incorporate biogeochemical feedback mechanisms such as aerosol effects on clouds. The primary purpose of a workshop recently held at the National Oceanic and Atmospheric Administration's David Skaggs Research Center was to define and discuss such coupled processes. Several scientific themes crucial for biogeochemical cycling emerged from the workshop, such as the importance of episodic events, precipitation, stratification, and the marginal ice zone.

Hunke, Elizabeth; Meier, Walt

2012-10-01

127

Flow Tube Studies of Gas Phase Chemical Processes of Atmospheric Importance  

NASA Technical Reports Server (NTRS)

The objective of this project is to conduct measurements of elementary reaction rate constants and photochemistry parameters for processes of importance in the atmosphere. These measurements are being carried out under temperature and pressure conditions covering those applicable to the stratosphere and upper troposphere, using the chemical ionization mass spectrometry turbulent flow technique developed in our laboratory.

Molina, Mario J.

1997-01-01

128

An important application of image processing and computer vision is the development of intelligent systems for  

E-print Network

1 Abstract An important application of image processing and computer vision is the development-time detection of moving vehicles approaching an intersection from sequences of color images acquired HSV color mapping to achieve feature space segmentation. Experimental results using real outdoor

Payeur, Pierre

129

Important processes in modeling and optimization of EUV lithography T. Sizyuk and A. Hassanein  

E-print Network

, and details of photon transport in these media. We studied the influence and the importance of various evolution and confinement can significantly influence EUV emission, which usually follows laser intensity profile in ideal LPP conditions. We analyzed the influence of the above processes on EUV source

Harilal, S. S.

130

The Extended Importance of the Social Creation of Value in Evolutionary Processes: A Proposed Model  

Microsoft Academic Search

In this paper I propose that the social creation of value is an important factor in the theoretical study of creativity, not only in cultural evolutionary processes but in the genetic evolution of spe- cific creative domains, with particular attention to music. I consider the possibility that music emerged in an autopoietic manner from the basic conditions of the social

Oliver Bown

131

9 CFR 130.4 - User fees for processing import permit applications.  

Code of Federal Regulations, 2010 CFR

...application 86.00 89.00 91.00 94.00 97.00 Processing an application for a permit to import fetal bovine serum when facility inspection is required Per application 455.00 469.00 483.00 497.00 512.00...

2010-01-01

132

9 CFR 130.4 - User fees for processing import permit applications.  

Code of Federal Regulations, 2012 CFR

...application 86.00 89.00 91.00 94.00 97.00 Processing an application for a permit to import fetal bovine serum when facility inspection is required Per application 455.00 469.00 483.00 497.00 512.00...

2012-01-01

133

9 CFR 130.4 - User fees for processing import permit applications.  

Code of Federal Regulations, 2011 CFR

...application 86.00 89.00 91.00 94.00 97.00 Processing an application for a permit to import fetal bovine serum when facility inspection is required Per application 455.00 469.00 483.00 497.00 512.00...

2011-01-01

134

9 CFR 130.4 - User fees for processing import permit applications.  

Code of Federal Regulations, 2013 CFR

...application 86.00 89.00 91.00 94.00 97.00 Processing an application for a permit to import fetal bovine serum when facility inspection is required Per application 455.00 469.00 483.00 497.00 512.00...

2013-01-01

135

9 CFR 130.4 - User fees for processing import permit applications.  

...application 86.00 89.00 91.00 94.00 97.00 Processing an application for a permit to import fetal bovine serum when facility inspection is required Per application 455.00 469.00 483.00 497.00 512.00...

2014-01-01

136

Mitochondrial import and processing of an in vitro synthesized human prebranched chain acyltransferase fragment.  

PubMed Central

A 1.6-kb cDNA for human liver branched-chain acyltransferase [E2b] was placed in a transcription vector under the control of the SP6 promoter. In vitro translation of transcripts from this vector produced a pre-E2b fragment of Mr 39,000. Following import into mitochondria, this protein was processed to a protein with an Mr of 36,000. The processed protein was fully protected from trypsin digestion. Import and processing did not occur in the presence of rhodamine 123 or carbonyl cyanide m-chlorophenyl hydrazone, suggesting that membrane potential and coupled respiration were required. Uptake and processing were species and tissue independent, since both mouse-liver and human-lymphoblast mitochondria converted the human pre-E2b protein fragment. Mitochondria from patient cells that lack E2b through an inherited defect were able to import and process the in vitro-made protein, suggesting that the inherited defect was in the gene for E2b and not in the organelle-structure function. This system now provides additional methods for investigation of mechanisms responsible for the human inherited disorders affecting the branched-chain alpha-ketoacid dehydrogenase complex. Images Figure 2 Figure 3 Figure 4 PMID:3189339

Litwer, S; Danner, D J

1988-01-01

137

On the potential vegetation feedbacks that enhance phosphorus availability - insights from a process-based model linking geological and ecological time scales  

NASA Astrophysics Data System (ADS)

In old and heavily weathered soils, the availability of P might be so small that the primary production of plants is limited. However, plants have evolved several mechanisms to actively take up P from the soil or mine it to overcome this limitation. These mechanisms involve the active uptake of P mediated by mycorrhiza, biotic de-occlusion through root clusters, and the biotic enhancement of weathering through root exudation. The objective of this paper is to investigate how and where these processes contribute to alleviate P limitation on primary productivity. To do so, we propose a process-based model accounting for the major processes of the carbon, water, and P cycle including chemical weathering at the global scale. We use simulation experiments to assess the relative importance of the different uptake mechanisms to alleviate P limitation on biomass production. Implementing P limitation on biomass synthesis allows the assessment of the efficiencies of biomass production across different ecosystems. We find that active P-uptake is an essential mechanism for sustaining P availability on long time scales, whereas biotic de-occlusion might serve as a buffer on time scales shorter than 10 000 yr. Although active P uptake is essential for reducing P losses by leaching, humid lowland soils reach P limitation after around 100 000 yr of soil evolution. Given the generalized modeling framework, our model results compare reasonably with observed or independently estimated patterns and ranges of P concentrations in soils and vegetation. Furthermore, our simulations suggest that P limitation might be an important driver of biomass production efficiency (the fraction of the gross primary productivity used for biomass growth), and that vegetation on older soils becomes P-limited leading to a smaller biomass production efficiency. With this study, we provide a theoretical basis for investigating the responses of terrestrial ecosystems to P availability linking geological and ecological time scales under different environmental settings.

Buendíia, C.; Arens, S.; Hickler, T.; Higgins, S. I.; Porada, P.; Kleidon, A.

2013-12-01

138

On the potential vegetation feedbacks that enhance phosphorus availability - insights from a process-based model linking geological and ecological timescales  

NASA Astrophysics Data System (ADS)

In old and heavily weathered soils, the availability of P might be so small that the primary production of plants is limited. However, plants have evolved several mechanisms to actively take up P from the soil or mine it to overcome this limitation. These mechanisms involve the active uptake of P mediated by mycorrhiza, biotic de-occlusion through root clusters, and the biotic enhancement of weathering through root exudation. The objective of this paper is to investigate how and where these processes contribute to alleviate P limitation on primary productivity. To do so, we propose a process-based model accounting for the major processes of the carbon, water, and P cycles including chemical weathering at the global scale. Implementing P limitation on biomass synthesis allows the assessment of the efficiencies of biomass production across different ecosystems. We use simulation experiments to assess the relative importance of the different uptake mechanisms to alleviate P limitation on biomass production. We find that active P uptake is an essential mechanism for sustaining P availability on long timescales, whereas biotic de-occlusion might serve as a buffer on timescales shorter than 10 000 yr. Although active P uptake is essential for reducing P losses by leaching, humid lowland soils reach P limitation after around 100 000 yr of soil evolution. Given the generalized modelling framework, our model results compare reasonably with observed or independently estimated patterns and ranges of P concentrations in soils and vegetation. Furthermore, our simulations suggest that P limitation might be an important driver of biomass production efficiency (the fraction of the gross primary productivity used for biomass growth), and that vegetation on old soils has a smaller biomass production rate when P becomes limiting. With this study, we provide a theoretical basis for investigating the responses of terrestrial ecosystems to P availability linking geological and ecological timescales under different environmental settings.

Buendía, C.; Arens, S.; Hickler, T.; Higgins, S. I.; Porada, P.; Kleidon, A.

2014-07-01

139

Geological Processes Affecting the Thermal Structures of Shallow Seafloor: An Example from offshore SW Taiwan  

NASA Astrophysics Data System (ADS)

Fluid migration pattern is important for understanding the structural features of a mountain belt and for hydrocarbon exploration. However, these patterns are difficult to measure on the seafloor. Using phase properties of the gas hydrates, we studied the fluid flow patterns offshore southwestern Taiwan. Seismic explorations in this region show wide spreading bottom-simulating-reflectors (BSR), which is interpreted as the bottom of the gas hydrate stability zone. It provides us an opportunity to study possible fluid flow patterns at several hundred meters sub-bottom depths of the marine sediments. First, we used BSR-based geothermal gradient patterns to derive 1D vertical fluid flow models by analyzing the Péclet numbers. We found the regional fluid flow rates ranges from 6 cm/yr to 43 cm/yr, then we also discovered several prospect sites to examine the fluid migration pattern in the environs of active, passive and deformation front. Next, we forward 2D steady-state temperature fields of these sites to account for the topographic effects to compare with the BSR-based temperature. The discrepancy between the 2D conductive thermal model and the BSR-based temperature was interpreted as a result of fluid migration. And furthermore, we built 3D steady-state temperature fields, for comparing with BSR-based temperatures, to detail describe the regional temperature discrepancy with the structure evolution in 3D seismic data. We discovered our interpreted fluid migration patterns are consistent with the regional structure. The BSR-based temperatures in Yung-An Ridge, which is in active margin, are higher than the conduction model near faults and chimney zones, we interpret that it is possible active dewatering inside the accretionary prism to allow fluid to migrate upward here. For the upper reach of Peng-Hu Canyon, which is across deformation front, we found the disequilibrium temperature field probably induced by the recently landslide. For the Formosa Ridge in passive margin, the BSR-based temperatures are colder than the theoretical model, especially on the flanks. We suggested that cold seawater is moving into the ridge from the flanks, cooling the ridge, and then some of the fluid is expelled at the ridge top. On the sum, the shallow temperature fields are strongly affected by 2D or 3D topographic effects, but we can still gain much information regarding fluid flow patterns through modeling. The new method we proposed will be helpful on assess the risk or value on energy exploration.

Chen, Liwen; Chi, Wu-Cheng; Wu, Shao-Kai; Liu, Char-Shine; Lu, Chia-Yu

2014-05-01

140

Geologic Map of North America  

USGS Multimedia Gallery

The Geologic Map of North America is a product of GSA's Decade of North American Geology (DNAG) project. At a scale of 1:5,000,000, this map covers ~15% of Earth's surface and differs from previous maps in several important respects: it is the first such map to depict the geology of the seafloor, th...

2010-06-25

141

Isotope Tracer Studies of Diffusion in Sillicates and of Geological Transport Processes Using Actinide Elements  

SciTech Connect

The objectives were directed toward understanding the transport of chemical species in nature, with particular emphasis on aqueous transport in solution, in colloids, and on particles. Major improvements in measuring ultra-low concentrations of rare elements were achieved. We focused on two areas of studies: (1) Field, laboratory, and theoretical studies of the transport and deposition of U, Th isotopes and their daughter products in natural systems; and (2) Study of calcium isotope fractionation effects in marine carbonates and in carbonates precipitated in the laboratory, under controlled temperature, pH, and rates of precipitation. A major study of isotopic fractionation of Ca during calcite growth from solution has been completed and published. It was found that the isotopic shifts widely reported in the literature and attributed to biological processes are in fact due to a small equilibrium fractionation factor that is suppressed by supersaturation of the solution. These effects were demonstrated in the laboratory and with consideration of the solution conditions in natural systems, where [Ca{sup 2+}] >> [CO{sub 3}{sup 2-}] + [HCO{sub 3}{sup -}]. The controlling rate is not the diffusion of Ca, as was earlier proposed, but rather the rate of supply of [CO{sub 3}{sup 2-}] ions to the interface. This now opens the issues of isotopic fractionation of many elements to a more physical-chemical approach. The isotopic composition of Ca {Delta}({sup 44}Ca/{sup 40}Ca) in calcite crystals has been determined relative to that in the parent solutions by TIMS using a double spike. Solutions were exposed to an atmosphere of NH{sub 3} and CO{sub 2}, provided by the decomposition of (NH4)2CO3. Alkalinity, pH, and concentrations of CO{sub 3}{sup 2-}, HCO{sub 3}{sup -}, and CO{sub 2} in solution were determined. The procedures permitted us to determine {Delta}({sup 44}Ca/{sup 40}Ca) over a range of pH conditions, with the associated ranges of alkalinity. Two solutions with greatly different Ca concentrations were used, but, in all cases, the condition [Ca] >> [CO{sub 3}{sup 2-}] was met. A wide range in {Delta}({sup 44}Ca/{sup 40}Ca) was found for the calcite crystals, extending from 0.04 {+-} 0.13 to -1.34 {+-} 0.15 {per_thousand}, generally anticorrelating with the amount of Ca removed from the solution. The results show that {Delta}({sup 44}Ca/{sup 40}Ca) is a linear function of the saturation state of the solution with respect to calcite ({Omega}). The two parameters are very well correlated over a wide range in {Omega} for each solution with a given [Ca]. Solutions, which were vigorously stirred, showed a much smaller range in {Delta}({sup 44}Ca/{sup 40}Ca) and gave values of -0.42 {+-} 0.14 {per_thousand}, with the largest effect at low {Omega}. It is concluded that the diffusive flow of CO{sub 3}{sup 2-} into the immediate neighborhood of the crystal-solution interface is the rate-controlling mechanism and that diffusive transport of Ca{sup 2+} is not a significant factor. The data are simply explained by the assumptions that: (a) the immediate interface of the crystal and the solution is at equilibrium with {Delta}({sup 44}Ca/{sup 40}Ca) {approx} -1.5 {+-} 0.25 {per_thousand}, and (b) diffusive inflow of CO{sub 3}{sup 2-} causes supersaturation, thus precipitating Ca from the regions, exterior to the narrow zone of equilibrium. We consider this model to be a plausible explanation of the available data reported in the literature. The well-resolved but small and regular isotope fractionation shifts in Ca are thus not related to the diffusion of very large hydrated Ca complexes, but rather due to the ready availability of Ca in the general neighborhood of the crystal solution interface. The largest isotopic shift which occurs is a small equilibrium effect which is then subdued by supersaturation precipitation for solutions where [Ca{sup 2+}] >> [CO{sub 3}{sup 2-}] + [HCO{sub 3}{sup -}]. It is shown that there is a clear temperature dependence of the net isotopic shifts, which is simply due to changes in {Omega}

Wasserburg, Gerald J

2008-07-31

142

Modelling of processes occurring in deep geological repository - Development of new modules in the GoldSim environment  

NASA Astrophysics Data System (ADS)

Three new modules modelling the processes that occur in a deep geological repository have been prepared in the GoldSim computer code environment (using its Transport Module). These modules help to understand the role of selected parameters in the near-field region of the final repository and to prepare an own complex model of the repository behaviour. The source term module includes radioactive decay and ingrowth in the canister, first order degradation of fuel matrix, solubility limitation of the concentration of the studied nuclides, and diffusive migration through the surrounding bentonite layer controlled by the output boundary condition formulated with respect to the rate of water flow in the rock. The corrosion module describes corrosion of canisters made of carbon steel and transport of corrosion products in the near-field region. This module computes balance equations between dissolving species and species transported by diffusion and/or advection from the surface of a solid material. The diffusion module that includes also non-linear form of the interaction isotherm can be used for an evaluation of small-scale diffusion experiments.

Vopálka, D.; Lukin, D.; Vokál, A.

2006-01-01

143

Vesta's Geological Features  

NASA Astrophysics Data System (ADS)

Vesta’s diverse geology exhibits impact basins and craters of all sizes and unusual shapes, ejecta blankets, large troughs, impact basins, enigmatic dark material, and considerable evidence for mass wasting and surface alteration processes.

Jaumann, R.; Russell, C. T.; Raymond, C. A.; Pieters, C. M.; Yingst, R. A.; Williams, D. A.; Buczkowski, D. L.; Schenk, P.; De Sanctis, M. C.

2014-02-01

144

ASTRONAUT'S GUIDE TO TERRESTRIAL IMPACT CRATERS R. A. F. Grieve, Geological Survey of Canada  

E-print Network

#12;#12;ASTRONAUT'S GUIDE TO TERRESTRIAL IMPACT CRATERS R. A. F. Grieve, Geological Survey Gosses Bluff Possible Impact Craters Itturalde, Bolivia Aorounga, Chad Lac Iro, Chad AI Madafi, Saudi but not particularly important phenomenon in the spectrum of geologic process. Our concept of the importance of impact

Rathbun, Julie A.

145

Tectonomagmatic evolution of the terrestrial planets: importance for understanding of processes of their formation and subsequent development  

NASA Astrophysics Data System (ADS)

Our knowledge about formation and evolution of the terrestrial planets (the Earth, Venus, Mars, Mercury and, possibly, the Moon) based on different physical and geochemical speculations and models. The main disadvantage of such hypotheses is their abstract character and ignoring any data on tectonomagmatic evolution of those planets. At the same time, just this type of data provide an important information, which is necessary for elaborating of a present-day theory of their formation and evolution. The Earth has been much better studied compared to the other planets, therefore we will discuss the main questions of planetary tectonomagmatic evolution using the Earth as example plus involve other data on the Moon and the terrestrial planets. Two dominating hypotheses about composition of the primordial Earth's crust exist now: (1) traditional implies that the primordial crust had basic composition, whereas the sialic crust resulted from a geosyncline process or, in modern terms, from processes at convergent plate margins, and (2) primordial crust was sialic; the plate tectonic mechanisms started in the Middle Paleoproterozoic and resulted in oceanic spreading and formation of the secondary oceanic crust. Both models require a global melting of a primary chondritic material to form the primordial crust. The final result depends on the degree of melt differentiation during solidification of a magmatic ocean. Such a solidification, due to differences between adiabatic and melting-points gradients had to proceed in bottom-top direction (Jeffries, 1929) and resulted in accumulation of low-temperature derivates in the primordial crust. Geological data, namely granite-dominated Archean crust, and results of studying of detrital zircon from Australia supports the primordial-sialic crust hypothesis. The Moon which is four times smaller than Earth has a basic primordial crust. Such a difference can be explained by different depths of their magmatic oceans. The Early Precambrian (Archean, Early Paleoproterozoic) tectonomagmatic activity on the Earth was rather different from the Phanerozoic: the major features then were huge granite-greenstone terranes (GGTs) and their separating granulite belts; mantle melts were derived from a depleted source. The GGTs consisting of greenstone belts with komatiite-basaltic magmatism in Archean, "submerged" in granite gneiss matrix, probably, strong reworked primordial sialic crust, and by siliceous high-Mg series (SHMS) in early Paleoproterozoic. GGTs were areas of extension, uplifting and denudation, whereas the granulite belts were dominated by compression, sinking and sedimentation. Generally, the Early Precambrian geological pattern was rather different from the modern plate tectonics and can be described in plumetectonics terms. A drastic change of the tectonomagamtic and ecology processes on it's surface occurred at ca. 2.3-2.0 Ga: instead of high-Mg magmas appeared geochemical enriched Fe-Ti pucrites and basalts, and the plume tectonic was changed by plate tectonics, which is still active now, as well as ecologic situation on the surface. Since that time the primordial sialic continental crust has been gradually replaced by the secondary basaltic oceanic crust. Systematic consumption of the ancient crust in subduction zones obviously started at ~2 Ga and led to gradually replacing it by the secondary mafic (oceanic) crust. The crustal materials has stored in the "slab cemeteries", revealed in the mantle by seismic tomography. Tectonomagmatic evolution of the Moon began4.4-4.0 Ga in lunar highlands with low-Ti magnesium suite, analogous to the terrestrial Paleoproterozoic SHMS. Cardinal change of tectonomagmatic processes, close to that on the Earth, happed on the Moon ~3.9 Ga to form large depressions of lunar maria with thinned crust and vast basaltic volcanism with signatures of plume magmatism (high-Ti basalts). The lunar maria were, probably, specific analogues of Earth's oceans. On Venus and Mars also two main types of morphostructures, which are vast fields of basal

Sharkov, E.; Bogatikov, O.

2009-04-01

146

General Surveillance for Import and Processing: the EuropaBio approach  

Microsoft Academic Search

:  Applications for placing on the market of genetically modified organisms (GMOs) for import, food, feed and processing under\\u000a Directive 2001\\/18\\/EC and Regulation (EC) No 1829\\/ 2003, have to include a monitoring plan conforming with Annex VII to Directive\\u000a 2001\\/18\\/EC. One aspect of this monitoring plan is the need for general surveillance to identify the occurrence of adverse\\u000a effects of the

P. Windels; E. Alcalde; E. Lecoq; G. Legris; A. Pleysier; B. Tinland; C. Wandelt

2009-01-01

147

Geologic mapping of Vesta  

NASA Astrophysics Data System (ADS)

We report on a preliminary global geologic map of Vesta, based on data from the Dawn spacecraft's High-Altitude Mapping Orbit (HAMO) and informed by Low-Altitude Mapping Orbit (LAMO) data. This map is part of an iterative mapping effort; the geologic map has been refined with each improvement in resolution. Vesta has a heavily-cratered surface, with large craters evident in numerous locations. The south pole is dominated by an impact structure identified before Dawn's arrival. Two large impact structures have been resolved: the younger, larger Rheasilvia structure, and the older, more degraded Veneneia structure. The surface is also characterized by a system of deep, globe-girdling equatorial troughs and ridges, as well as an older system of troughs and ridges to the north. Troughs and ridges are also evident cutting across, and spiraling arcuately from, the Rheasilvia central mound. However, no volcanic features have been unequivocally identified. Vesta can be divided very broadly into three terrains: heavily-cratered terrain; ridge-and-trough terrain (equatorial and northern); and terrain associated with the Rheasilvia crater. Localized features include bright and dark material and ejecta (some defined specifically by color); lobate deposits; and mass-wasting materials. No obvious volcanic features are evident. Stratigraphy of Vesta's geologic units suggests a history in which formation of a primary crust was followed by the formation of impact craters, including Veneneia and the associated Saturnalia Fossae unit. Formation of Rheasilvia followed, along with associated structural deformation that shaped the Divalia Fossae ridge-and-trough unit at the equator. Subsequent impacts and mass wasting events subdued impact craters, rims and portions of ridge-and-trough sets, and formed slumps and landslides, especially within crater floors and along crater rims and scarps. Subsequent to the formation of Rheasilvia, discontinuous low-albedo deposits formed or were emplaced; these lie stratigraphically above the equatorial ridges that likely were formed by Rheasilvia. The last features to be formed were craters with bright rays and other surface mantling deposits. Executed progressively throughout data acquisition, the iterative mapping process provided the team with geologic proto-units in a timely manner. However, interpretation of the resulting map was hampered by the necessity to provide the team with a standard nomenclature and symbology early in the process. With regard to mapping and interpreting units, the mapping process was hindered by the lack of calibrated mineralogic information. Topography and shadow played an important role in discriminating features and terrains, especially in the early stages of data acquisition.

Yingst, R. A.; Mest, S. C.; Berman, D. C.; Garry, W. B.; Williams, D. A.; Buczkowski, D.; Jaumann, R.; Pieters, C. M.; De Sanctis, M. C.; Frigeri, A.; Le Corre, L.; Preusker, F.; Raymond, C. A.; Reddy, V.; Russell, C. T.; Roatsch, T.; Schenk, P. M.

2014-11-01

148

Importance of "Process Evaluation" in Audiological Rehabilitation: Examples from Studies on Hearing Impairment  

PubMed Central

The main focus of this paper is to discuss the importance of “evaluating the process of change” (i.e., process evaluation) in people with disability by studying their lived experiences. Detailed discussion is made about “why and how to investigate the process of change in people with disability?” and some specific examples are provided from studies on patient journey of persons with hearing impairment (PHI) and their communication partners (CPs). In addition, methodological aspects in process evaluation are discussed in relation to various metatheoretical perspectives. The discussion has been supplemented with relevant literature. The healthcare practice and disability research in general are dominated by the use of outcome measures. Even though the values of outcome measures are not questioned, there seems to be a little focus on understanding the process of change over time in relation to health and disability. We suggest that the process evaluation has an additional temporal dimension and has applications in both clinical practice and research in relation to health and disability.

Manchaiah, Vinaya; Danermark, Berth; Ronnberg, Jerker; Lunner, Thomas

2014-01-01

149

Utah Geology  

NSDL National Science Digital Library

Utah Geological Survey's Web site, Utah Geology, offers a variety of interesting geological information about the state. Good descriptions, illustrations, and photographs can be accessed on earthquakes and hazards, dinosaurs and fossils, rocks and minerals, oil and energy, and more. For example, the Rocks and Minerals page contains everything from how to stake a mining claim to downloadable summaries of mineral activity in the state. There is quite a bit of information within the site, and anyone interested in geology will find themselves exploring these pages for quite a while.

2001-01-01

150

Testing the Late Noachian Icy Highlands Model: Geological Observations, Processes and Origin of Fluvial and Lacustrine Features.  

NASA Astrophysics Data System (ADS)

A new reconstruction of the Late Noachian Mars atmosphere and climate shows atmosphere-surface thermal coupling and an adiabatic cooling effect producing preferential distribution of snow and ice in the highlands. In this Late Noachian Icy Highlands (LNIH) scenario, snow and ice accumulate in the south circumpolar region and in the higher altitudes of the southern uplands, but the mean annual temperature is everywhere below freezing. How can the abundant evidence for water-related fluvial and lacustrine activity (valley networks, VN; open-basin lakes, OBL; closed-basin lakes; CBL) be reconciled with the icy highlands model? We investigate the nature of geologic processes operating in the icy highlands and use the Antarctic McMurdo Dry Valleys (MDV) as guidance in understanding and assessing how melting might be taking place. In the MDV, mean annual temperatures (MAT) are well below freezing. This results in a thick regional permafrost layer, the presence of an ice-table at shallow depths, and an overlying dry active layer. This configuration produces a perched aquifer and a horizontally stratified hydrologic system, where any melting results in local saturation of the dry active layer and channelized flow on top of the ice table. Top-down melting results in the dominance of lateral water transport, in contrast to temperate climates with vertical infiltration and transport to the groundwater table. Despite subzero MAT, MDV peak seasonal and peak daytime temperatures can exceed 273K and have a strong influence on the melting of available water ice. We present maps of the predicted distribution of LNIH snow and ice, compare these to the distribution of VN, OBL and CBL, and assess how top-down and bottom-up melting processes might explain the formation of these features in an otherwise cold and icy LN Mars. We assess the global near-surface water budget, analyze thickness estimates to distinguish areas of cold-based and wet-based glaciation, analyze the state of the ice cover and its susceptibility to melting and runoff, and describe top-down melting and fluvial channel formation processes in a LNIH environment. We find that: 1) episodic top-down melting of the LNIH is a robust mechanism to produce the observed fluvial and lacustrine features; 2) the characteristics and distribution of features in the Dorsa Argentea Formation are consistent with an extensive circum-polar ice cap during LNIH time; and 3) the nature of preserved LN impact craters is consistent with impact cratering processes in the LNIH environment. 393 words.

Head, James; Wordsworth, Robin; Forget, Francis; Madeleine, Jean-Baptiste; Halvey, Italy

2014-05-01

151

Some Opinions on Remote Sensing and Geologic Studies  

NASA Technical Reports Server (NTRS)

The principal role of remote sensing data in geologic studies is as a source of geologic information from which meaningful geologic interpretations can be made. Remote sensing data are important in sedimentary basin analysis and other geologic studies as independent and sometimes unique sources of important lithologic and structural information; however, their greatest benefit to exploration-oriented investigations may come when these data are used with other relevant data in a digital database approach to exploration. Modern computer technology facilitates the rapid integration and synthesis of satellite, topographic, gravity, aeromagnetic, geochemical, and other data collected from a given region. Once such data are geometrically registered, they can be digitally processed, within the constraints of defined geologic models, to rapidly identify, and focus further exploration efforts on, target areas that have the greatest potential for success.

Bailey, G. B.

1985-01-01

152

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.

153

Submitted as a chapter for The Geology of Virginia, edited by Chuck Bailey, College of William and Mary Coastal Processes and Offshore Geology  

E-print Network

of Virginia results from the interactions of modern processes, primarily waves, tidal currents and sea climate changes. The scarps that formed by shoreline erosion during highstands of sea level and the very each segment of the shore. The gross characterization of Virginia's coast as the Delmarva Peninsula

Krantz, David

154

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.

155

Species sorting and neutral processes are both important during the initial assembly of bacterial communities  

PubMed Central

Many studies have shown that species sorting, that is, the selection by local environmental conditions is important for the composition and assembly of bacterial communities. On the other hand, there are other studies that could show that bacterial communities are neutrally assembled. In this study, we implemented a microcosm experiment with the aim to determine, at the same time, the importance of species sorting and neutral processes for bacterial community assembly during the colonisation of new, that is, sterile, habitats, by atmospheric bacteria. For this we used outdoor microcosms, which contained sterile medium from three different rock pools representing different environmental conditions, which were seeded by rainwater bacteria. We found some evidence for neutral assembly processes, as almost every 4th taxon growing in the microcosms was also detectable in the rainwater sample irrespective of the medium. Most of these taxa belonged to widespread families with opportunistic growth strategies, such as the Pseudomonadaceae and Comamonadaceae, indicating that neutrally assembled taxa may primarily be generalists. On the other hand, we also found evidence for species sorting, as one out of three media selected a differently composed bacterial community. Species sorting effects were relatively weak and established themselves via differences in relative abundance of generalists among the different media, as well as media-specific occurrences of a few specific taxa. In summary, our results suggest that neutral and species sorting processes interact during the assembly of bacterial communities and that their importance may differ depending on how many generalists and specialists are present in a community. PMID:21270841

Langenheder, Silke; Szekely, Anna J

2011-01-01

156

Geology of caves  

USGS Publications Warehouse

A cave is a natural opening in the ground extending beyond the zone of light and large enough to permit the entry of man. Occurring in a wide variety of rock types and caused by widely differing geological processes, caves range in size from single small rooms to intercorinecting passages many miles long. The scientific study of caves is called speleology (from the Greek words spelaion for cave and logos for study). It is a composite science based on geology, hydrology, biology, and archaeology, and thus holds special interest for earth scientists of the U.S. Geological Survey.

Morgan, I. M., Davies, W. E.

1991-01-01

157

Geological Development of Panama  

Microsoft Academic Search

The Panama that geologists see today is a young landscape that in form comprises a reclined S-shaped, generally E-W oriented\\u000a isthmus produced through complex geotectonic processes that created and assembled a diverse suite of geological units since\\u000a late Cretaceous\\/early Tertiary time. The geological development of Panama is a consequence of the relative motions of the\\u000a North and South American continental

Russell S. Harmon

158

Conduct of Geologic Field Work During Planetary Exploration: Why Geology Matters  

NASA Technical Reports Server (NTRS)

The science of field geology is the investigative process of determining the distribution of rock units and structures on a planet fs surface, and it is the first-order data set that informs all subsequent studies of a planet, such as geochemistry, geochronology, geophysics, or remote sensing. For future missions to the Moon and Mars, the surface systems deployed must support the conduct of field geology if these endeavors are to be scientifically useful. This lecture discussed what field geology is all about.why it is important, how it is done, how conducting field geology informs many other sciences, and how it affects the design of surface systems and the implementation of operations in the future.

Eppler, Dean B.

2010-01-01

159

Geologic guide to the island of Hawaii: A field guide for comparative planetary geology  

NASA Technical Reports Server (NTRS)

With geological data available for all inner planets except Venus, we are entering an era of true comparative planetary geology, when knowledge of the differences and similarities for classes of structures (e.g., shield volcanoes) will lead to a better understanding of general geological processes, regardless of planet. Thus, it is imperative that planetologists, particularly those involved in geological mapping and surface feature analysis for terrestrial planets, be familiar with volcanic terrain in terms of its origin, structure, and morphology. One means of gaining this experience is through field trips in volcanic terrains - hence, the Planetology Conference in Hawaii. In addition, discussions with volcanologists at the conference provide an important basis for establishing communications between the two fields that will facilitate comparative studies as more data become available.

Greeley, R. (editor)

1974-01-01

160

From seed production to seedling establishment: Important steps in an invasive process  

NASA Astrophysics Data System (ADS)

It is widely accepted that exotic invasive species are one of the most important ecological and economic problems. Reproductive and establishment traits are considered key features of a population expansion process, but few works have studied many of these simultaneously. This work examines how large the differences are in reproductive and establishment traits between two Fabaceae, the exotic invasive, Gleditsia triacanthos and the native, Acacia aroma. Gleditsia is a serious leguminous woody invader in various parts of the world and Acacia is a common native tree of Argentina. Both species have similar dispersal mechanisms and their reproductive phenology overlaps. We chose 17 plants of each species in a continuous forest of the Chaco Serrano Forest of Córdoba, Argentina. In each plant we measured fruit production, fruit removal (exclusion experiments), seed predation (pre- and post-dispersal), seed germination, seed bank (on each focal tree, three sampling periods during the year), and density of seedlings (around focal individuals and randomly in the study site). Gleditsia presented some traits that could favour the invasion process, such as a higher number of seeds per plant, percentage of scarified seed germination and density of seedlings around the focal individuals, than Acacia. On the other hand, Gleditsia presented a higher percentage of seed predation. The seed bank was persistent in both species and no differences were observed in fruit removal. This work highlights the importance of simultaneously studying reproductive and establishment variables involved in the spreading of an exotic invasive species. It also gives important insight into the variables to be considered when planning management strategies. The results are discussed from the perspective of some remarkable hypotheses on invasive species and may contribute to rethinking some aspects of the theory on invasive species.

Ferreras, Ana Elisa; Galetto, Leonardo

2010-03-01

161

Geologic Resource Evaluation of Kaloko-Honokohau National Historical Park, Hawai'i: Geology and Coastal Landforms  

USGS Publications Warehouse

Geologic resource inventories of lands managed by the National Park Service (NPS) are important products for the parks and are designed to provide scientific information to better manage park resources. Park-specific geologic reports are used to identify geologic features and processes that are relevant to park ecosystems, evaluate the impact of human activities on geologic features and processes, identify geologic research and monitoring needs, and enhance opportunities for education and interpretation. These geologic reports are planned to provide a brief geologic history of the park and address specific geologic issues that link the park geology and the resource manager. The Kona coast National Parks of the Island of Hawai'i are intended to preserve the natural beauty of the Kona coast and protect significant ancient structures and artifacts of the native Hawaiians. Pu'ukohola Heiau National Historic Site (PUHE), Kaloko-Honokohau National Historical Park (KAHO), and Pu'uhonua O Honaunau National Historical Park (PUHO) are three Kona parks studied by the U.S. Geological Survey (USGS) Coastal and Marine Geology Team in cooperation with the National Park Service. This report is one of six related reports designed to provide geologic and benthic-habitat information for the three Kona parks. Each geology and coastal-landform report describes the regional geologic setting of the Hawaiian Islands, gives a general description of the geology of the Kona coast, and presents the geologic setting and issues for one of the parks. The related benthic-habitat mapping reports discuss the marine data and habitat classification scheme, and present results of the mapping program. Kaloko-Honokohau National Historical Park (KAHO) was established in 1978 in order to preserve and protect traditional native Hawaiian culture and cultural sites. The park is the site of an ancient Hawaiian settlement, occupies 469 ha and is considered a locale of considerable cultural and historical significance. Cultural resources include fishponds, petroglyphs and a heiau (religious site). The fishponds are also recognized as exceptional birding areas and are important wetlands for migratory birds. The ocean and reef have been designated as a Marine Area Reserve, where green sea turtles commonly come ashore to rest. The park is also a valuable recreational resource, with approximately 4 km of coastline and a protective cove ideal for snorkeling and swimming. KAHO park boundaries extend beyond the mean high tide line and include the adjacent marine environment. An accompanying report for KAHO presents the results of benthic habitat mapping of the offshore waters, from the shoreline to approximately 40 m water depth. Ground-water quality and potential downslope impacts created by development around the park are of concern to Park management.

Richmond, Bruce M.; Gibbs, Ann E.; Cochran, Susan A.

2008-01-01

162

The relative importance of microbial nitrate reduction processes in an agriculturally-impacted estuary  

NASA Astrophysics Data System (ADS)

Human activities are increasing reactive nitrogen levels worldwide. Reactive nitrogen exists largely as nitrate and may be ecologically harmful to nutrient-limited systems. Nitrate loadings to the environment may be transformed by the microbial nitrate reduction processes of denitrification (converting nitrate to dinitrogen gas), or of dissimilatory nitrate reduction to ammonium (DNRA) (allowing reactive nitrogen to persist). The predominant nitrate reduction pathway largely determines the nitrogen removal capacity of the estuary. Therefore, identifying the relative importance of denitrification and DNRA in a given system provides insight into how much nitrate is transformed to dinitrogen and ammonium. Estuary sediments often have high nitrate reduction rates, but the environmental factors that determine which process prevails are underexplored. Nitrate availability and salinity are thought to influence which nitrate reduction process predominates. Elkhorn Slough is a small California estuary that experiences a range of nitrate concentrations (0 to over 2,000 ?M) and salinities (0 to 33.5) depending on the agricultural runoff introduced through the Old Salinas River and the tidal influence. This study investigates how the fluctuating nutrient and salinity conditions found over the diel cycle at the interface of the Old Salinas River and Elkhorn Slough influences the nitrogen transformation rates observed. Benthic denitrification and DNRA are evaluated using whole sediment core incubations amended with an overlying 15NO3- labeled pool. Rates of denitrification and DNRA in the sediment are calculated using the isotope pairing technique. The results of this research will help elucidate the relative importance of dissimilatory nitrate removal pathways in an agriculturally-impacted estuary and ultimately reveal whether anthropogenic nitrate inputs are preserved or removed from the system.

Cardarelli, E.; Francis, C. A.

2013-12-01

163

Vesta: A Geological Overview  

NASA Astrophysics Data System (ADS)

The Dawn spacecraft has collected over 28,000 images and a wealth of spectral data providing nearly complete coverage of Vesta’s surface with multiple views. These data enable analysis of Vesta’s diverse geology including impact craters of all sizes and unusual shapes, a variety of ejecta blankets, large troughs extending around the equatorial region, impact basins, enigmatic dark material, and considerable evidence for mass wasting and surface alteration features (1). Two large impact basins, Veneneia (400km) underlying the larger Rheasilvia basin (500km) dominate the south pole (1,2). Rheasilvia exhibits a huge central peak, with total relief of -22km to 19km, and steep scarps with mass wasting features. Vesta’s global tectonic patterns (two distinct sets of large troughs almost parallel to the equator) strongly correlate with the locations of the two south polar impact basins, and were likely created by their formation (1,3). Numerous unusual asymmetric impact craters and ejecta indicate the strong role of topographic slope in cratering processes on Vesta (1). Such very steep topographic slopes are near to the angle of repose; slope failures make resurfacing due to impacts and their associated gravitational slumping and seismic effects an important geologic process on Vesta (1). Outcrops in crater walls indicate reworked crustal material and impact melt in combination with clusters of pits that show thermal surface processes (4). Relatively dark material of still unknown origin is intermixed in the regolith layers and partially excavated by younger impacts yielding dark outcrops, rays and ejecta (1,5). Finally, Vesta’s surface is younger than expected (6). (1) Jaumann, et al., 2012, Science 336, 687-690; (2) Schenk et al., 2012, Science 336, 964-967; (3) Buczkowski, et al., 2012, GRL, submitted; (4) Denevi, et al., 2012, Science, submitted; (5) McCord, et al., 2012, Nature, submitted; (6) Marchi, et al., 2012, Science 336, 690-694.

Ralf, Jaumann; Russell, C. T.; Raymond, C. A.; Pieters, C. M.; Yingst, R. A.; Williams, D. A.; Buczkowski, D. L.; Schenk, P.; Denevi, B.; Krohn, K.; Stephan, K.; Roatsch, T.; Preusker, F.; Otto, K.; Mest, S. C.; Ammannito, E.; Blewett, D.; Carsenty, U.; DeSanctis, C. M.; Garry, W.; Hiesinger, H.; Keller, H. U.; Kersten, E.; Marchi, S.; Matz, K. D.; McCord, T. B.; McSween, H. Y.; Mottola, S.; Nathues, A.; Neukum, G.; O'Brien, D. P.; Schmedemann, N.; Scully, J. E. C.; Sykes, M. V.; Zuber, M. T.

2012-10-01

164

INFLUENCE OF TIDAL FORCES (THE EARTH - MOON SUN SYSTEM) ON SOME GEOLOGICAL PROCESSES IN THE EARTH'S CRUST  

Microsoft Academic Search

It was shown that oscillating regime of tidal evolution in the Earth - Moon - Sun system results in periodical changes of velocity rotation and incline angle of the axis rotation. According to geological data it has been distinguished epoch intervals of maximum Phanerozoic sedimentation, magmatism and folding stages. These are compared with calculated changes of velocities and orientation of

Yu. N. Avsjuk; S. Genshaft; F. Sokolova; S. P. Svetlosanova

165

Geologic Maps and Geologic Structures: A Texas Example  

NSDL National Science Digital Library

This Historical Geology lab exercise is an accompaniment to lab class instruction about geologic structures (folding and faulting) and geologic maps. It also serves as an excellent introduction to the Geology of the state of Texas. "Coloring" geologic maps, an important part of the exercise, may seem like a very elementary learning technique. But this lab engages students actively, and since the subject is often already somewhat familiar to them, emphasizing both the geology and geography of Texas, students receive it enthusiastically. This activity could be adapted to other regions, since most states have color 8 1/2 by 11 geologic maps available. A color map could be scanned and modified in Photoshop to create a simplified black and white version as was done in the assignment handout.

Steinberg, Roger

166

Geologic History  

NSDL National Science Digital Library

This unit introduces younger students to the concept of relative versus absolute time and how geologists determine the age of geologic events and features. Topics include the laws that determine relative age (superposition, cross-cutting relationships, included fragments, and others), and how to re-construct the geologic history of an area using these relationships. There is also information on geologic correlation and the use of index fossils to determine relative age. The section on absolute time discusses some ways of measurement (tree rings, radioactive dating) and introduces the concepts of natural selection and mass extinctions. A vocabulary and downloadable, printable student worksheets are provided.

Medina, Philip

2010-09-03

167

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

168

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

169

The CB1 receptor as an important mediator of hedonic reward processing.  

PubMed

The endocannabinoid (ECB) system has emerged recently as a key mediator for reward processing. It is well known that cannabinoids affect appetitive learning processes and can induce reinforcing and rewarding effects. However, the involvement of the ECB system in hedonic aspects of reward-related behavior is not completely understood. With the present study, we investigated the modulatory role of the ECB system on hedonic perception, measured by the pleasure attenuated startle (PAS) paradigm for a palatable food reward. Here, a conditioned odor is thought to induce a pleasant affective state that attenuates an aversive reflex-the acoustic startle response. Modulatory effects of the CB1 receptor antagonist/inverse agonist SR1411716 and the cannabinoid agonist WIN 55?212-2 on PAS were examined in rats. PAS was also measured in CB1 receptor knockout (KO) and wild-type (WT) mice. Pharmacological inhibition as well as the absence of CB1 receptors was found to reduce PAS, whereas WIN 55?212-2 administration increased PAS. Finally, presentation of a conditioned reward cue was found to induce striatal FosB/?FosB expression in WT mice, but not in KO mice, indicating a reduced stimulation of reward-related brain regions in conditioned KO mice by odor presentation. We here show that in addition to our previous studies in rats, PAS may also serve as a valuable and suitable measure to assess hedonic processing in mice. Our data further indicate that the ECB system, and in particular CB1 receptor signaling, appears to be highly important for the mediation of hedonic aspects of reward processing. PMID:24718372

Friemel, Chris M; Zimmer, Andreas; Schneider, Miriam

2014-09-01

170

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

171

An evaluation of the relative importance of formulation and process variables using factorial design.  

PubMed

A factorial design method for assessing the relative importance of various formulation and process factors and their interactions in model paracetamol tablets is described. The design was a 2 X 2 X 2 X 3 type using mixing time, starch concentration, drug particle size and compaction pressure respectively. The starch concentration was the most significant factor in affecting the dissolution rate but the larger drug particle size also gave a significant increase in drug release rate. Interactions between starch concentration and drug size and between these and mixing time were also observed. The most significant factor affecting the tensile fracture stress of the tablets was the mixing time, followed in order by the drug particle size, starch concentration and compaction pressure. PMID:6151968

Sanderson, I M; Kennerley, J W; Parr, G D

1984-12-01

172

Importance of the accretion process in asteroid thermal evolution: 6 Hebe as an example  

NASA Astrophysics Data System (ADS)

Widespread evidence exists for heating that caused melting, thermal metamorphism, and aqueous alteration in meteorite parent bodies. Previous simulations of asteroid heat transfer have assumed that accretion was instantaneous. For the first time, we present a thermal model that assumes a realistic (incremental) accretion scenario and takes into account the heat budget produced by decay of 26Al during the accretion process. By modeling 6 Hebe (assumed to be the H chondrite parent body), we show that, in contrast to results from instantaneous accretion models, an asteroid may reach its peak temperature during accretion, the time at which different depth zones within the asteroid attain peak metamorphic temperatures may increase from the center to the surface, and the volume of high-grade material in the interior may be significantly less than that of unmetamorphosed material surrounding the metamorphic core. We show that different times of initiation and duration of accretion produce a spectrum of evolutionary possibilities, and thereby, highlight the importance of the accretion process in shaping an asteroid's thermal history. Incremental accretion models provide a means of linking theoretical models of accretion to measurable quantities (peak temperatures, cooling rates, radioisotope closure times) in meteorites that were determined by their thermal histories.

Ghosh, A.; Weidenschilling, S. J.; McSween, H. Y., Jr.

2003-05-01

173

State-of-the-Art Article: The Role and Importance of Lower-Level Processes in Second Language Reading  

ERIC Educational Resources Information Center

This article examines current research on the role and importance of lower-level processes in second language (L2) reading. The focus is on word recognition and its subcomponent processes, including various phonological and orthographic processes. Issues related to syntactic and semantic processes and their relationship with word recognition are…

Nassaji, Hossein

2014-01-01

174

Relative importance of breakage and decay as processes depleting large wood from streams  

NASA Astrophysics Data System (ADS)

Large wood pieces affect virtually every physical, chemical, and biological process in fluvial systems, including hydraulics, transport of materials, algal biomass accrual, nutrient uptake, and trophic interactions. The processes that deplete wood are thus of broad importance to stream ecosystems. We assessed the relative contributions for breakage-induced mobilization (where pieces are more prone to transport as a result of breakage into shorter parts) and gradual biochemical decay to wood depletion rates in a field study on 12 northern Minnesota, USA, streams. Wood pieces > 0.05 m in diameter for a portion > 1 m in length were individually tagged (n = 651), measured, and remeasured a year later. Pieces showed significant reductions in density and branching complexity (i.e., branches and twigs) and 22% of pieces broke (i.e., lost 10% or more of length). Processes related to breakage and decay were examined using Bayesian structural equation modeling and multiple regression. Breakage was more likely for pieces that were thin in diameter, long, deeply submerged, braced, buried, and traveled long distances. Pieces lost more density if they were initially dense, traveled a long distance, were not deeply submerged, lacked bark, were thin in diameter, were steeply pitched, were long, and were not buried. Pieces lost more branching complexity if they were complex with little gap between them and the streambed. Actual mass losses related to breakage and decay were 7.3% and 1.9% (respectively), both less than the 36% observed for total fluvial export. In contrast to the associations of breakage and decay with structural properties of the wood pieces and their position, hydraulic and geomorphic variables (stream power, slope, velocity, width) had little effect.

Merten, Eric C.; Vaz, Pedro G.; Decker-Fritz, Jo A.; Finlay, Jacques C.; Stefan, Heinz G.

2013-05-01

175

The Geology of Vesta  

NASA Astrophysics Data System (ADS)

The Dawn spacecraft collected over 28,000 images and a wealth of spectral data of Vesta's surface. These data enable analysis of Vesta's diverse geology including impact craters of all sizes and unusual shapes, a variety of ejecta blankets, large troughs, impact basins, enigmatic dark material, and considerable evidence for mass wasting and surface alteration processes [1,2,3]. Two large impact basins, Veneneia underlying the larger Rheasilvia basin dominate the south polar region [1,4]. The depression surrounding Vesta's south pole was formed by two giant impacts about one billion and two billion years ago [4,5]. Vesta's global tectonic patterns (two distinct sets of large troughs orthogonal to the axes of the impacts) strongly correlate with the locations of the two south polar impact basins, and were likely created by their formation [1,6]. Numerous unusual asymmetric impact craters and ejecta indicate the strong influence of topographic slope in cratering on Vesta [1]. One type of gully in crater walls is interpreted to form by dry granular flow, but another type is consistent with transient water flow [7]. Very steep topographic slopes near to the angle of repose are common; slope failures make resurfacing due to impacts and their associated gravitational slumping and seismic effects an important geologic process on Vesta [1]. Clusters of pits in combination with impact melt [8] suggest the presence of volatile materials underlying that melt in some crater floors. Relatively dark material of uncertain origin is intermixed in the regolith layers and partially excavated by younger impacts yielding dark outcrops, rays and ejecta [1,9]. Vesta's surface is reworked by intense impacts and thus much younger than the formation of its crust [2,5].

Jaumann, R.; Russell, C. T.; Raymond, C. A.; Pieters, C. M.; Yingst, R. A.; Williams, D. A.; Buczkowski, D. L.; Krohn, K.; Otto, K.; Stephan, K.; DeSanctis, M. C.; Garry, W. B.; Blewett, D.

2013-09-01

176

27 CFR 41.1 - Importation of tobacco products, cigarette papers and tubes, and processed tobacco.  

Code of Federal Regulations, 2013 CFR

...false Importation of tobacco products, cigarette papers and tubes, and...TOBACCO IMPORTATION OF TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND...41.1 Importation of tobacco products, cigarette papers and tubes,...

2013-04-01

177

27 CFR 41.1 - Importation of tobacco products, cigarette papers and tubes, and processed tobacco.  

Code of Federal Regulations, 2011 CFR

...false Importation of tobacco products, cigarette papers and tubes, and...TOBACCO IMPORTATION OF TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND...41.1 Importation of tobacco products, cigarette papers and tubes,...

2011-04-01

178

27 CFR 41.1 - Importation of tobacco products, cigarette papers and tubes, and processed tobacco.  

...false Importation of tobacco products, cigarette papers and tubes, and...TOBACCO IMPORTATION OF TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND...41.1 Importation of tobacco products, cigarette papers and tubes,...

2014-04-01

179

27 CFR 41.1 - Importation of tobacco products, cigarette papers and tubes, and processed tobacco.  

Code of Federal Regulations, 2012 CFR

... true Importation of tobacco products, cigarette papers and tubes, and...TOBACCO IMPORTATION OF TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND...41.1 Importation of tobacco products, cigarette papers and tubes,...

2012-04-01

180

Fatigue and fatigue crack growth processes in hard tissues: The importance of age and surface integrity  

NASA Astrophysics Data System (ADS)

With the progressive increase in partially and fully dentate seniors, fracture has become an increasingly common form of restored tooth failure. Dentin undergoes progressive changes in microstructure with patient age, and studies are now suggesting that there is a reduction in fatigue strength and fatigue crack growth resistance of this tissue. This dissertation explores aging of dentin, the influence of flaws that are introduced during restorative processes on the fatigue properties of dentin, and proposes models for characterizing the damage initiation and growth process during fatigue of dentin. Results from this investigation show that the fatigue crack growth properties (Paris Law parameters (C, m) andDeltaKth) of human dentin undergo the most significant changes at a patient age of 42 years. Based on the fatigue crack growth responses, three age groups were established including young (age?33), aged (34?age ?49) and old (50?age) patients for further analysis. There were significant differences in the initiation and growth behavior between the tissues of patients from the three age groups. With regards to the influence of restorative processes, there was no influence on the quasi-static responses of dentin. However, the endurance limit of dentin treated with the dental burs (28 MPa) and abrasive air jet (35 MPa) were approximately 36% and 20% lower than that of the control (44 MPa), respectively. Both cutting processes caused a significant reduction (p?0.0001) in fatigue strength. An accumulative damage model was developed to characterize fatigue of the control and bur treated dentin as well as provide a model for fatigue life prediction. The damage models were derived as a function of number of loading cycles (N), and ratio of applied stress to ultimate strength (r). The developed models provide estimations for the initial state of damage, the state of damage during the life, as well as the damage accumulation rate for cyclic loading of dentin. Using the experimental findings, a Damage Effect Model (DEM) was also developed to describe the influence of flaws introduced by bur treatment on fatigue of dentin. The DEM showed that the damage caused by bur treatment is uniform and independent of tubule orientation. Using the developed DEM for dentin with 0° tubule orientation, material constants of bur treated dentin with 90° orientation were estimated and used in predicting fatigue for controlled experimental conditions involving a notched fatigue approach. Overall, the results of this study provide fundamental knowledge concerning the influence of aging and cutting processes on the fatigue properties of dentin. These findings are of substantial importance to the field of restorative dentistry, and potentially establish the need for treating senior patients with an approach that is unique from that of younger patients. The damage models developed in this investigation are the first that have been developed for hard tissues, and provide a foundation for future research aimed at modeling fatigue processes in hard tissues including bone and dentin.

Majd, Hessam

181

Incorporating risk attitude into Markov-process decision models: importance for individual decision making.  

PubMed

Most decision models published in the medical literature take a risk-neutral perspective. Under risk neutrality, the utility of a gamble is equivalent to its expected value and the marginal utility of living a given unit of time is the same regardless of when it occurs. Most patients, however, are not risk-neutral. Not only does risk aversion affect decision analyses when tradeoffs between short- and long-term survival are involved, it also affects the interpretation of time-tradeoff measures of health-state utility. The proportional time tradeoff under- or overestimates the disutility of an inferior health state, depending on whether the patient is risk-seeking or risk-averse (it is unbiased if the patient is risk-neutral). The authors review how risk attitude with respect to gambles for survival duration can be incorporated into decision models using the framework of risk-adjusted quality-adjusted life years (RA-QALYs). They present a simple extension of this framework that allows RA-QALYs to be calculated for Markov-process decision models. Using a previously published Markov-process model of surgical vs expectant treatment for benign prostatic hypertrophy (BPH), they show how attitude towards risk affects the expected number of QALYs calculated by the model. In this model, under risk neutrality, surgery was the preferred option. Under mild risk aversion, expectant treatment was the preferred option. Risk attitude is an important aspect of preferences that should be incorporated into decision models where one treatment option has upfront risks of morbidity or mortality. PMID:9219195

Cher, D J; Miyamoto, J; Lenert, L A

1997-01-01

182

Physical Characteristics, Geologic Setting, and Possible Formation Processes of Spring Deposits on Mars Based on Terrestrial Analogs  

NASA Technical Reports Server (NTRS)

Spring formation is a predicted consequence of the interaction of former Martian aquifers with structures common to Mars, including basin margins, Tharsis structures, and other structural deformation characteristics. The arid environment and high abundance of water soluble compounds in the crust will have likewise encouraged spring deposit formation at spring sites. Such spring deposits may be recognized from morphological criteria if the characteristics of formation and preservation are understood. An important first step in the current Mars exploration strategy [10] is the detection of sites where there is evidence for past or present near-surface water on Mars. This study evaluates the large-scale morphology of spring deposits and the physical processes of their formation, growth, and evolution in terms that relate to (1) their identification in image data, (2) their formation, evolution, and preservation in the environment of Mars, and (3) their potential as sites of long-term or late stage shallow groundwater emergence at the surface of Mars.

Crumpler, L. S.

2003-01-01

183

Importance of microbial soil organic matter processing in dissolved organic carbon production.  

PubMed

Soil dissolved organic carbon (DOC) sources and its seasonal dynamics are poorly known. We aimed to determine the contribution of plant and soil organic matter (SOM) to size classes of DOC in a field experiment with C3 to C4 vegetation change on two soil types through different seasons. Stable isotope ratios of DOC size classes were measured using size exclusion chromatography (SEC) coupled online to liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). SEC resolved DOC into three size classes: very high molecular weight/vHMW (> 10 kDa), high molecular weight/HMW (0.4-10 kDa), and low molecular weight/LMW (< 0.4 kDa). HMW DOC was most abundant in all seasons, soil types, and depths. In contrast, vHMW DOC was only seen postsnowmelt in upper 20 cm and was mainly (87 ± 9%) plant-derived. Through all seasons, HMW and LMW DOC had less than 30% recent plant contribution. Similar size range and source of DOC size classes and soil chloroform fumigation extracts suggest microbial origin of DOC. Thus, microbial SOM recycling is an important process in DOC production. We suggest that DOC molecules get partitioned manifold between soil solution and the mineral matrix (chromatography), thereby getting constantly decomposed, altered, or produced anew by soil microorganisms (reactive transport). PMID:23870024

Malik, Ashish; Gleixner, Gerd

2013-10-01

184

Atmospheric Chemistry of Polybrominated Diphenyl Ethers: The Importance of Photolysis as a Fate Process  

NASA Astrophysics Data System (ADS)

Polybrominated diphenyl ethers (PBDEs) are heavily used as flame-retardants in polyurethane foam and synthetic commercial fibers. These semivolatile compounds have between 2 and 10 bromines and have been found to undergo long-range atmospheric transport to remote regions such as the Arctic Circle, where they enter food chains and biomagnify in top predators. Unfortunately, existing environmental fate models are unable to accurately describe the long-range transport potential of these compounds due to a lack of comprehensive data on the physical and chemical properties of PBDEs, especially those that describe photolysis in the vapor and particle phases. We have used a small-volume reaction chamber coupled to a mass spectrometer to measure the gas-phase quantum yields of select PBDEs relative to well-characterized actinometers. Our results are used to derive photolysis lifetimes of PBDEs and enable us, in conjunction with our measured OH rate constants and estimates of deposition velocities, to understand and quantify the most important loss processes for PBDEs in the atmosphere.

Raff, J. D.; Hites, R. A.

2006-12-01

185

Page 1 | B.S. in Geology | Academic Plan of Study Updated April 2014 B.S. in Geology  

E-print Network

in topics like sedimentology, structural geology and mineralogy. Extracurricular experiences are important in the subjects of geomorphology, sedimentology, and structural geology. In addition, students at UNC Charlotte

Raja, Anita

186

Process-Response Numerical Modeling in Carbonate Systems - Current Status and Importance (Invited)  

NASA Astrophysics Data System (ADS)

Developing predictive models of carbonate systems has important implications for monitoring and managing global climate change affecting societies around the world. Carbonate sediments and rocks form an important part of the global carbon cycle. More than 80% of Earth’s carbon is locked up in carbonate rocks, and is the primary ultimate sink for CO2 introduced into the atmosphere. Reefs and carbonate platforms, in general, are sensitive climatic indicators, and contain important records of past climate change. Ancient carbonate platforms and systems play a significant role in the global economy. They are the raw material for construction, and through their high permeability’s and porosities, carbonate rocks serve as important fresh water aquifers and petroleum reservoirs. They host more than half of the world’s petroleum. The systems that produce carbonate sediments have multiple interacting biologic, chemical, and hydrodynamic elements. Carbonate sediments are originally and predominantly derived from biological mineralization directly from seawater. Waves, tides, and marine currents can redistribute these sediments landward into lagoons or tidal flats, send them seaward into the deep or sea, or trap them within the hydraulic regime in which they originated. The characteristics of carbonate sediments are thus sensitive to environmental parameters like light, bathymetry, temperature, salinity, turbidity, nutrient and oxygen levels, hydrodynamics, and mineral saturation states. Localized buildups of carbonate sediments can alter the local hydraulic regime and change the nature of surrounding sediments. The prospect of modeling carbonates in detail has been daunting. Existing carbonate models are a class of rule-based ‘simulations’ with limited predictive qualities. The earliest computer models of carbonate deposition were 1-D and 2-D, and essentially modeled carbonates as “in-place” accumulations of sediment. In most cases, sediment production in these models was directly related to water depth based on assumptions that carbonate production is a function of light attenuation with depth. These models were followed by so-called “geometric” models (SedPak), where sediment transport was allowed, and models were based on simply depositing sediment vertically into assumed shoreline geometries. There are computer models of carbonate deposition that model wave and current dynamics over platforms and then base sediment erosion, transport and deposition on the results of the circulation modeling: Carb3D and Carb3D+, Dionysus and Carbonate GPM. In addition, Carb3D+ approximates some diagenetic processes as a function of hydrologic residence times. New types of rule-based models, such as cellular automata have also been developed that model the interaction of many different elements of carbonate deposition. Based on this progress, and with recent advances in ecological modeling, treating uncertainty in models, high performance computing, and handling heterogeneous and linguistic data types, the time is right to tackle the challenges of mathematically modeling carbonate sediments.

Sarg, J.; Jenkins, C. J.; Burgess, P. M.; Budd, D. A.; Rankey, E. C.; Demicco, R. V.

2009-12-01

187

Geology Before Pluto: Pre-encounter Considerations  

NASA Astrophysics Data System (ADS)

Jeffrey M. Moore (NASA Ames) and the New Horizons Science Team Pluto, its large satellite Charon, and its four small known satellites represent the first trans-Neptunian Kuiper Belt objects populating the outer-most solar system beyond the gas giant planets to be studied in detail from a spacecraft (New Horizons). A complete picture of the solar nebula and solar system formation cannot be confidently formulated until representatives of this group of bodies at the edge of solar space have been examined. The Pluto system is composed of unique, lunar- and intermediate-sized objects that can tell us much about how objects with volatile icy compositions evolve. Modeling of the interior suggests that geologic activity may have been significant to some degree, and observations of frost on the surface could imply the need for a geologic reservoir for the replenishment of these phases. However, these putative indicators of Pluto's geologic history are inconclusive and unspecific. Detailed examination of Pluto's geologic record is the only plausible means of bridging the gap between theory and observation. In this talk I will examine the potential importance of these tentative indications of geologic activity and how specific spacecraft observations have been designed and used to constrain the Pluto system's geologic history. The cameras of New Horizons will provide robust data sets that should be immanently amenable to geological analysis of the Pluto System's landscapes. In this talk, we begin with a brief discussion of the planned observations by the New Horizons cameras that will bear most directly on geological interpretability. Then I will broadly review major geological processes that could potentially operate on the surfaces of Pluto and its moons. I will first survey exogenic processes (i.e. those for which energy for surface modification is supplied externally to the planetary surface): impact cratering, sedimentary processes (including volatile migration), and the work of wind. I will conclude with an assessment of the prospects for endogenic activity in the form of tectonics and cryo-volcanism.

Moore, Jeffrey

2014-05-01

188

Antarctica Geology  

NSDL National Science Digital Library

This site contains information about the continent of Antarctica. There is a classroom practice and instructional module. The students will be able to describe the general geology of the land under the Antarctic ice and to explain from where the rocks may have come.

189

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

190

Importance sampling for jump processes and applications to Laetitia Badouraly Kassim  

E-print Network

of a continuous diffusion (ie. driven by a Brownian motion) and a compound Poisson process. In this work, we process or possibly the sum of independent compound Poisson processes in the multidimensional case. We will concentrate on such jump diffusions with a Brownian driven part and a jump part written as a compound Poisson

Paris-Sud XI, Université de

191

Geology 12. Curriculum Guide.  

ERIC Educational Resources Information Center

This publication, developed by the Ministry of Education, Province of British Columbia, Canada, is a teaching guide for the Geology 12 course. The course is intended to provide secondary school students with the background and desire to investigate their earth, its materials and its processes. The guide consists of the following four sections: (1)…

British Columbia Dept. of Education, Victoria.

192

Project Primary Geology  

NSDL National Science Digital Library

Project Primary is a collaboration of professors from the departments of Botany-Microbiology, Chemistry, Education, Geology, Physics, and Zoology at Ohio Wesleyan University and K-3 teachers from Ohio's Delaware, Marion, and Union Counties to produce hands-on activities for the teaching of science. The geology activities are appropriate for children in grades K-12. Collectively, the goals for these activities are to demonstrate the inter-relatedness of life and the physical planet, the importance of understanding scientific phenomena for all people, not just future scientists, to impart knowledge which leads through student curiosity to continued inquiry, and to spur creativity. Topics covered include earthquakes, behavior of Earth materials, plate tectonics, the surface of the Earth, volcanoes, and geologic time and the evolution of the Earth.

Fryer, Karen

193

Laboratory studies of potentially important atmospheric processes involving oxides of nitrogen  

NASA Astrophysics Data System (ADS)

The work presented in this dissertation comprises two major objectives. The first objective has been to carry out an investigation of the production of N2O from reactions of electronically and vibrationally excited atmospheric trace species with N2 (using tunable diode laser absorption spectroscopy as the N2O detection method). The second objective of this study has been to accurately investigate the kinetics of the important stratospheric reaction O(3P) + NO2 --> O2 + NO (k1) (using the technique of laser flash photolysis-resonance fluorescence). Investigation of N2O production from the collisional deactivation of electronically excited NO 2 and OH by N2 and from the interaction of nascent O 3 with N2 have resulted in upper limit quantum yields which render all three processes as insignificant sources of atmospheric N 2O. The following expression adequately describes the observed temperature dependence of the rate coefficient for the reaction O(1D) + N2 + M --> N2O + M (k2) in its third order low-pressure limit over the temperature range 220-324 K: k2,0(T) = (2.72 +/- 0.08) × 10-36 (T/300)-(0.92 +/- 0.37) cm6 molecule-2 s-1, where the uncertainties represent precision at the 2? level. The accuracy of the reported rate coefficients is estimated to range from 30 to 40%. Preliminary calculations indicate that reaction 2 represents a source of about 0.2 Tg N2O per year to the atmosphere (i.e., about 1% of the currently estimated global source budget of N 2O). This is the first suggested mechanism that generates N2O photochemically in the atmosphere that is capable of explaining the altitude dependence of the N2O isotopic signature. The following Arrhenius expression adequately describes the observed temperature dependence of the rate coefficient for reaction 1: k1(T ) = (4.21 +/- 0.25) × 10-12 exp[(273 +/- 18)/T] cm3 molecule-1 s-1, where the uncertainties represent precision at the 2? level. The accuracy of the reported values for k 1(T) is estimated to be +/-6% over the entire temperature range investigated (221-425 K). Incorporation of our kinetics results for reaction 1 into models of stratospheric chemistry would lead to somewhat lower mid-stratospheric ozone levels than would be obtained using results of previous studies.

Estupinan, Edgar Garcia

2001-12-01

194

The relative importance of hydrophobicity in determining runoff-infiltration processes in burned forest soils  

NASA Astrophysics Data System (ADS)

Wildfires induce fundamental changes to vegetation and soil structure/texture which conseqeuntly have major impacts on infiltration capacity, overland flow generation, runoff and sediment yields. The relative importance, however, of fire-induced soil water repellency (WR) on hydrological and erosional processes is somewhat controversial, partially, as the direct effects of soil WR in-situ field conditions have been difficult to isolate. It is generally accepted that hydrophobicity is caused by the formation of organic substances in forest soils, while burning is considered to enhance this process. Given the complex response of the soil-vegetation system to burning, soil WR is only one of several affecting soil hydrology. Other factors include the physical sealing of soils triggered by rain drops energy, the increase in soil erodibility due to changes in soil aggregates, and the role of the ash in sealing the burned surface. The degree and spatial distribution of WR burned varies considerably with fire severity, soil and vegetation type, soil moisture content and time since burning. Nevertheless, given the inverse relationship between soil moisture and hydrophobicity, the role of the latter in determining overland flow during wet winters when the soil is mostly inundated, is marginal. Following a 60 ha wildfire, which took place at the Pe'eram catchment during July 2009, we assessed the spatio-temporal distribution of WR in a burned Pinus halepensis forest. The site, located in the Upper Galille, Israel, was severely burned; the combustion removed all understory vegetation and burned down some of the trunks, leaving a thick layer of ash. The soils composed of reddish-brown clay loam forest soil and terra rossa on limestone bedrock, greyish light rendzina characterises the marl and chalk exposures. To consider the effect of distance from trees, in-situ hydrophobicity was assessed within a week, month and five months after the fire, using the WDPT test. Measurements were taken in concentric circles around the burned trees at two soil depths. We complemented this investigation by conducting a series of laboratory simulations. Non-burned soil was taken for laboratory analysis and rainfall simulations. Four treatment types were conducted: non-burned soil, non-burned soil + pine needles, burned soil without ash (300°C/15 min. after adding pine needles) and burned soil with the residue ash (300°C/15 min. after adding pine needles). Hydrophobicity was measured in all trays. Constant rainfall intensity of 30 mm/hr was simulated until terminal infiltration rates were reached. The experimental trays were oven dried and simulated again to imitate the effect of second rainstorm. Preliminary results indicate strong surface WR (60% >180s) at a distance of 1m and at the subsurface (50% >180s) directly by the trunk. In the control non-burned site stronger WR was found in proximity to the trunks. While in the burned sites extreme values (>300s) were apparent (15-35%) and correlated with distance from the trunk, no corresponding patterns were noticed in the control trees. The attempt to create homogeneous layer of WR under controlled laboratory conditions yielded a scattered pattern of repellency, similar to the field conditions. In contrast to expected, the bare soil and bare soil covered by needles exhibited the highest and lowest infiltration rates, respectively, while the burned hydrophobic soils demonstrated intermediate rates. It is thus suggested that in some soils, WR might enhance infiltration capacity by creating a complex mosaic of runoff-generating and runoff-absorbing micro-patches. In the experimental non-burned soil a rapid crusting of the surface provided lateral connectivity whilst the accumulation of litter and organic matter blanket the surface and enhance the vertical conductivity. To better understand the role of WR in generating hydrological response, it is required to consider the 3D 'sponge like' properties of the WR soils.

Wittenberg, Lea; Malkinson, Dan; Voogt, Annelies; Leska, Danny; Argaman, Eli; Keesstra, Saskia

2010-05-01

195

The U.S. Geological Survey Geo Data Portal: A web service architecture and implementation for geo-climate data access and processing  

NASA Astrophysics Data System (ADS)

Environmental modelers from fields of study including climatology, hydrology, geology, and ecology need common, cross-discipline data sources and processing methods to enable working with large remote datasets. Watershed modelers, for example, need downscaled climate model data and land-cover data summaries to predict streamflow for various future climate scenarios. In turn, ecological modelers need the predicted streamflow conditions to understand how habitat of biotic communities might be affected. The U.S. Geological Survey Geo Data Portal project addresses these needs by providing a flexible application built on open-standard Web services that integrates and streamlines data retrieval and analysis. Open Geospatial Consortium Web Processing Services (WPS) were developed to allow interoperable access to data from servers delivering both defacto standard Climate and Forecast (CF) convention datasets and OGC standard Web Coverage Services (WCS). The Geo Data Portal can create commonly needed derivatives of data in numerous formats. As an example use case, a user can upload a shapefile specifying a region of interest (e.g. a watershed), pick a climate simulation, and retrieve a spreadsheet of predicted daily maximum temperature in that region up to 2100. Outcomes of the Geo Data Portal project support the rapid development of user interfaces for accessing and manipulating environmental data. The Geo Data Portal resulting from this project will be demonstrated accessing a range of climate and landscape data.

Kunicki, T.; Blodgett, D. L.; Booth, N. L.; Suftin, I.; Walker, J. I.

2011-12-01

196

Importance of the 1n-stripping process in the 6Li + 159Tb reaction  

NASA Astrophysics Data System (ADS)

The inclusive cross sections of the ? particles produced in the reaction 6Li + 159Tb have been measured at energies around the Coulomb barrier. The measured cross sections are found to be orders of magnitude larger than the calculated cross sections of 6Li breaking into ? and d fragments, thus indicating contributions from other processes. The experimental cross sections of 1n-stripping and 1n-pickup processes have been determined from an entirely different measurement, reported earlier. Apart from incomplete fusion and d-transfer processes, the 1n-stripping process is found to be a significant contributor to the inclusive ?-particle cross sections in this reaction.

Pradhan, M. K.; Mukherjee, A.; Roy, Subinit; Basu, P.; Goswami, A.; Kshetri, R.; Palit, R.; Parkar, V. V.; Ray, M.; Saha Sarkar, M.; Santra, S.

2013-12-01

197

DEPARTMENT OF GEOLOGY & GEOPHYSICS UNDERGRADUATE  

E-print Network

DEPARTMENT OF GEOLOGY & GEOPHYSICS UNDERGRADUATE SURVIVAL MANUAL 2013-2014 SCHOOL OF OCEAN & EARTH at Manoa requirements 3 School of Ocean & Earth Science & Technology requirements 4 Departmental Student, stimulating opportunities for multidisciplinary discoveries of great intellectual and practical importance

198

Computing probabilities of very rare events for Langevin processes: a new method based on importance sampling  

E-print Network

Langevin equations are used to model many processes of physical interest, including low-energy nuclear collisions. In this paper we develop a general method for computing probabilities of very rare events (e.g. small fusion cross-sections) for processes described by Langevin dynamics. As we demonstrate with numerical examples as well as an exactly solvable model, our method can converge to the desired answer at a rate which is orders of magnitude faster than that achieved with direct simulations of the process in question.

O. Mazonka; C. Jarzynski; J. Blocki

1998-09-24

199

Reports of Planetary Geology Program, 1982  

NASA Technical Reports Server (NTRS)

Work conducted in the Planetary Geology program is summarized. The following categories are presented: outer solar system satellites; asteroids and comets; Venus; cratering processes and landform development; volcanic processes and landforms; aolian processes and landforms; fluvial processes and landform development; periglacial and permafrost processes; structure, tectonics and stratigraphy; remote sensing and regolith studies; geologic mapping, cartography and geodesy.

Holt, H. E. (compiler)

1982-01-01

200

Measuring Student Understanding of Geological Time  

ERIC Educational Resources Information Center

There have been few discoveries in geology more important than "deep time"--the understanding that the universe has existed for countless millennia, such that man's existence is confined to the last milliseconds of the metaphorical geological clock. The influence of deep time is felt in a variety of sciences including geology, cosmology, and…

Dodick, Jeff; Orion, Nir

2003-01-01

201

Patterns, processes and geological biases in the fossil record of jawless vertebrates at the time of jawed vertebrate origins  

NASA Astrophysics Data System (ADS)

The dominance of the jawed vertebrates over their jawless vertebrates in the Middle Palaeozoic represents a landmark evolutionary event in the history of vertebrates and a potential episode of competitive replacement. The timing and nature of the origin, radiation and extinction of each of the relevant clades of stem- and crown- gnathostomes is not, however, well understood. Here, stratigraphic, phylogenetic and palaeoenvironmental data for the closest relatives of jawed vertebrates (Osteostraci, Galeaspida and Thelodonti) are analysed. The Osteostraci and Galeaspida are restricted to shallow-water environments, and as such, are subject to facies biases resulting from sea-level change. Confidence intervals calculated upon the basis of non-random models of fossil recovery in light of sea-level changes stretch the potential origins of Osteostraci and Galeaspida into the Upper Ordovician, and are thus more compatible with phylogenetic schemes. Diversity changes through time for the Osteostraci, Galeaspida and Thelodonti were found to lie within the expected limits predicted from estimations of fossil record quality indicating that it is geological factors rather than biological that are responsible for apparent patterns. The relative demise and eventual extinction of ostracoderms during the Mid-Late Devonian is suggested to result from their inability to adapt to changing environmental conditions and their limited geo-dispersal ability rather than competition with their more generalist and cosmopolitan jawed relatives.

Sansom, R.; Donoghue, P.

2012-04-01

202

Influence of Introgression and Geological Processes on Phylogenetic Relationships of Western North American Mountain Suckers (Pantosteus, Catostomidae)  

PubMed Central

Intense geological activity caused major topographic changes in Western North America over the past 15 million years. Major rivers here are composites of different ancient rivers, resulting in isolation and mixing episodes between river basins over time. This history influenced the diversification of most of the aquatic fauna. The genus Pantosteus is one of several clades centered in this tectonically active region. The eight recognized Pantosteus species are widespread and common across southwestern Canada, western USA and into northern Mexico. They are typically found in medium gradient, middle-elevation reaches of rivers over rocky substrates. This study (1) compares molecular data with morphological and paleontological data for proposed species of Pantosteus, (2) tests hypotheses of their monophyly, (3) uses these data for phylogenetic inferences of sister-group relationships, and (4) estimates timing of divergence events of identified lineages. Using 8055 base pairs from mitochondrial DNA protein coding genes, Pantosteus and Catostomus are reciprocally monophyletic, in contrast with morphological data. The only exception to a monophyletic Pantosteus is P. columbianus whose mtDNA is closely aligned with C. tahoensis because of introgression. Within Pantosteus, several species have deep genetic divergences among allopatric sister lineages, several of which are diagnosed and elevated to species, bringing the total diversity in the group to 11 species. Conflicting molecular and morphological data may be resolved when patterns of divergence are shown to be correlated with sympatry and evidence of introgression. PMID:24619087

Unmack, Peter J.; Dowling, Thomas E.; Laitinen, Nina J.; Secor, Carol L.; Mayden, Richard L.; Shiozawa, Dennis K.; Smith, Gerald R.

2014-01-01

203

Chip-off-the-old-rock: the study of reservoir-relevant geological processes with real-rock micromodels.  

PubMed

We present a real-rock micromodel approach whereby microfluidic channels are fabricated in a naturally occurring mineral substrate. The method is applied to quantify calcite dissolution which is relevant to oil/gas recovery, CO2 sequestration, and wastewater disposal in carbonate formations - ubiquitous worldwide. The key advantage of this method is the inclusion of both the relevant substrate chemistry (not possible with conventional microfluidics) and real-time pore-scale resolution (not possible with core samples). Here, microchannels are etched into a natural calcite crystal and sealed with a glass slide. The approach is applied to study acidified brine flow through a single channel and a two-dimensional micromodel. The single-channel case conforms roughly to a 1-D analytical description, with crystal orientation influencing the local dissolution rate an additional 25%. The two-dimensional experiments show highly flow-directed dissolution and associated positive feedback wherein acid preferentially invades high conductivity flow paths, resulting in higher dissolution rates ('wormholing'). These experiments demonstrate and validate the approach of microfabricating fluid structures within natural minerals for transport and geochemical studies. More broadly, real-rock microfluidics open the door to a vast array of lab-on-a-chip opportunities in geology, reservoir engineering, and earth sciences. PMID:25236399

Song, Wen; de Haas, Thomas W; Fadaei, Hossein; Sinton, David

2014-10-14

204

Putting the pieces together: the geology of Alaska  

SciTech Connect

Geologic processes involved in the collisions of the various pieces of today's Alaska were also important to the generation and concentration of Alaska's mineral deposits. The recent theories of plate tectonics and several types of subduction zones are particularly appropriate to Alaska because the Aleutian Islands form a classic example of a subduction zone in action today. Southern Alaska and the Alaska Peninsula show many examples of subduction zones that have existed through geologic times. Rocks from different geological environments found close together has led to the concept of tectonstratigraphic terranes. Currently, Alaska has been subdivided into more than 50 tectonstratigraphic terranes by the US Geological Survey, but some may be subdivisions of larger, major terranes. Questions still to be answered are how much of Alaska was involved in the plate movement, when did the land arrive in Alaska, and what made up ancient Alaska. 6 figures.

Not Available

1982-01-01

205

The importance of observation versus process error in analyses of global ungulate populations.  

PubMed

Population abundance data vary widely in quality and are rarely accurate. The two main components of error in such data are observation and process error. We used Bayesian state space models to estimate the observation and process error in time-series of 55 globally distributed populations of two species, Cervus elaphus (elk/red deer) and Rangifer tarandus (caribou/reindeer). We examined variation among populations and species in the magnitude of estimates of error components and density dependence using generalized linear models. Process error exceeded observation error in 75% of all populations, and on average, both components of error were greater in Rangifer than in Cervus populations. Observation error differed significantly across the different observation methods, and predation and time-series length differentially affected the error components. Comparing the Bayesian model results to traditional models that do not separate error components revealed the potential for misleading inferences about sources of variation in population dynamics. PMID:24201239

Ahrestani, Farshid S; Hebblewhite, Mark; Post, Eric

2013-01-01

206

Laboratory studies of atomic collision processes of importance in planetary atmospheres  

NASA Technical Reports Server (NTRS)

Progress in the following research supported under NSG 7386 is reported: (1) measurement of differential cross sections for atomic and molecular collisions relevant to analysis and modeling of data from Pioneer 11, Pioneer 12, Voyager 1, and Voyager 2; (2) analysis of measured differential cross section results to provide scattering data in forms that are easy to apply to atmospheric modeling work; (3) analysis of the data to give basic information on the molecular potentials involved in the scattering process; and (4) development and initial use of apparatus to study dissociative processes in neutral molecules.

Stebbings, R. F.; Smith, K.

1984-01-01

207

Chapter 4: Geological Carbon Sequestration  

SciTech Connect

Carbon sequestration is the long term isolation of carbon dioxide from the atmosphere through physical, chemical, biological, or engineered processes. The largest potential reservoirs for storing carbon are the deep oceans and geological reservoirs in the earth's upper crust. This chapter focuses on geological sequestration because it appears to be the most promising large-scale approach for the 2050 timeframe. It does not discuss ocean or terrestrial sequestration. In order to achieve substantial GHG reductions, geological storage needs to be deployed at a large scale. For example, 1 Gt C/yr (3.6 Gt CO{sub 2}/yr) abatement, requires carbon capture and storage (CCS) from 600 large pulverized coal plants ({approx}1000 MW each) or 3600 injection projects at the scale of Statoil's Sleipner project. At present, global carbon emissions from coal approximate 2.5 Gt C. However, given reasonable economic and demand growth projections in a business-as-usual context, global coal emissions could account for 9 Gt C. These volumes highlight the need to develop rapidly an understanding of typical crustal response to such large projects, and the magnitude of the effort prompts certain concerns regarding implementation, efficiency, and risk of the enterprise. The key questions of subsurface engineering and surface safety associated with carbon sequestration are: (1) Subsurface issues: (a) Is there enough capacity to store CO{sub 2} where needed? (b) Do we understand storage mechanisms well enough? (c) Could we establish a process to certify injection sites with our current level of understanding? (d) Once injected, can we monitor and verify the movement of subsurface CO{sub 2}? (2) Near surface issues: (a) How might the siting of new coal plants be influenced by the distribution of storage sites? (b) What is the probability of CO{sub 2} escaping from injection sites? What are the attendant risks? Can we detect leakage if it occurs? (3) Will surface leakage negate or reduce the benefits of CCS? Importantly, there do not appear to be unresolvable open technical issues underlying these questions. Of equal importance, the hurdles to answering these technical questions well appear manageable and surmountable. As such, it appears that geological carbon sequestration is likely to be safe, effective, and competitive with many other options on an economic basis. This chapter explains the technical basis for these statements, and makes recommendations about ways of achieving early resolution of these broad concerns.

Friedmann, J; Herzog, H

2006-06-14

208

Some important imaging goals for asteroid missions  

NASA Technical Reports Server (NTRS)

Very high resolution imaging provides the best means of examining geological processes acting on asteroid surfaces. Imaging also may be important for revealing how asteroids accreted and for obtaining some data on their differentiation history. Imaging from rendezvous together with Doppler tracking is the only way to determine accurate densities and hence place limits on bulk composition.

Veverka, J.

1978-01-01

209

Geologic Time  

NSDL National Science Digital Library

This Classroom Connectors lesson plan discusses the characteristics of geologic time, including the law of superposition, fossil preservation, casts and molds, and various events through the history of the Earth. The site provides goals, objectives, an outline, time required, materials, activities, and closure ideas for the lesson. The Classroom Connectors address content with an activity approach while incorporating themes necessary to raise the activity to a higher cognition level. The major motivation is to employ instructional strategies that bring the students physically and mentally into touch with the science they are studying.

210

Measuring edge importance: a quantitative analysis of the stochastic shielding approximation for random processes on graphs.  

PubMed

Mathematical models of cellular physiological mechanisms often involve random walks on graphs representing transitions within networks of functional states. Schmandt and Galán recently introduced a novel stochastic shielding approximation as a fast, accurate method for generating approximate sample paths from a finite state Markov process in which only a subset of states are observable. For example, in ion-channel models, such as the Hodgkin-Huxley or other conductance-based neural models, a nerve cell has a population of ion channels whose states comprise the nodes of a graph, only some of which allow a transmembrane current to pass. The stochastic shielding approximation consists of neglecting fluctuations in the dynamics associated with edges in the graph not directly affecting the observable states. We consider the problem of finding the optimal complexity reducing mapping from a stochastic process on a graph to an approximate process on a smaller sample space, as determined by the choice of a particular linear measurement functional on the graph. The partitioning of ion-channel states into conducting versus nonconducting states provides a case in point. In addition to establishing that Schmandt and Galán's approximation is in fact optimal in a specific sense, we use recent results from random matrix theory to provide heuristic error estimates for the accuracy of the stochastic shielding approximation for an ensemble of random graphs. Moreover, we provide a novel quantitative measure of the contribution of individual transitions within the reaction graph to the accuracy of the approximate process. PMID:24742077

Schmidt, Deena R; Thomas, Peter J

2014-01-01

211

Measuring Edge Importance: A Quantitative Analysis of the Stochastic Shielding Approximation for Random Processes on Graphs  

PubMed Central

Mathematical models of cellular physiological mechanisms often involve random walks on graphs representing transitions within networks of functional states. Schmandt and Galán recently introduced a novel stochastic shielding approximation as a fast, accurate method for generating approximate sample paths from a finite state Markov process in which only a subset of states are observable. For example, in ion-channel models, such as the Hodgkin–Huxley or other conductance-based neural models, a nerve cell has a population of ion channels whose states comprise the nodes of a graph, only some of which allow a transmembrane current to pass. The stochastic shielding approximation consists of neglecting fluctuations in the dynamics associated with edges in the graph not directly affecting the observable states. We consider the problem of finding the optimal complexity reducing mapping from a stochastic process on a graph to an approximate process on a smaller sample space, as determined by the choice of a particular linear measurement functional on the graph. The partitioning of ion-channel states into conducting versus nonconducting states provides a case in point. In addition to establishing that Schmandt and Galán’s approximation is in fact optimal in a specific sense, we use recent results from random matrix theory to provide heuristic error estimates for the accuracy of the stochastic shielding approximation for an ensemble of random graphs. Moreover, we provide a novel quantitative measure of the contribution of individual transitions within the reaction graph to the accuracy of the approximate process. PMID:24742077

2014-01-01

212

Photon production through multi-step processes important in nuclear resonance fluorescence experiments  

NASA Astrophysics Data System (ADS)

We present calculations describing the production of photons through multi-step processes occurring when a beam of gamma-rays interacts with a macroscopic material. These processes involve the creation of energetic electrons through Compton scattering, photo-absorption and pair production, the subsequent scattering of these electrons, and the creation of energetic photons occurring as these electrons are slowed through Bremsstrahlung emission. Unlike single Compton collisions, during which an energetic photon that is scattered through a large angle loses most of its energy, these multi-step processes result in a sizable flux of energetic photons traveling at large angles relative to an incident photon beam. These multi-step processes are also a key background in experiments that measure nuclear resonance fluorescence by shining photons on a thin foil and observing the spectrum of back-scattered photons. Effective cross sections describing the production of back-scattered photons are presented in a tabular form that allows simple estimates of backgrounds expected in a variety of experiments. Incident photons with energies between 0.5 MeV and 8 MeV are considered. These calculations of effective cross sections may be useful for those designing NRF experiments or systems that detect specific isotopes in well-shielded environments through observation of resonance fluorescence.

Hagmann, C.; Pruet, J.

2007-06-01

213

The Importance of Flow, Thermal, and Resource Pulses for Floodplain Processes  

Microsoft Academic Search

In floodplains, flow, temperature, and resource pulses interact in complex ways and maintain biodiversity and biological productivity in these systems. We investigated the driving force of multiple pulses (i.e. flow, temperature, resource) on ecosystem processes in semi-natural floodplains in Central Europe (Val Roseg, Tagliamento, Danube). We used imaging techniques to quantify thermal patch dynamics over diel cycles and inundation patterns

K. Tockner; S. D. Langhans; M. Doering; C. Tanner; U. Uehlinger

2005-01-01

214

The Importance of Flow, Thermal, and Resource Pulses for Floodplain Processes  

NASA Astrophysics Data System (ADS)

In floodplains, flow, temperature, and resource pulses interact in complex ways and maintain biodiversity and biological productivity in these systems. We investigated the driving force of multiple pulses (i.e. flow, temperature, resource) on ecosystem processes in semi-natural floodplains in Central Europe (Val Roseg, Tagliamento, Danube). We used imaging techniques to quantify thermal patch dynamics over diel cycles and inundation patterns at the landscape scale. In the proglacial Val Roseg floodplain, surface temperature exhibited a complex spatiotemporal pattern, with values from -5° C to 30° C over a diel cycle. Furthermore, we studied the differential effects of alternating drying and wetting cycles on leaf litter decomposition and sediment respiration. Based on these data, we identified key habitats of ecosystem processes at the floodplain scale. Locations of organic matter input, storage, and processing were spatially separated. In the Tagliamento, standing stock of CPOM, for example, was up to 800g/m2 on vegetated islands but less than 20g/m2 in channels. Decomposition rate, however, was k = 0.0129 in channels compared to k = 0.0013 on islands. Finally, by overlaying different pulses, we identified "windows of ecological opportunity"; i.e., crucial time periods when conditions were most favourable to foster ecosystem processes and therefore to control floodplain biota.

Tockner, K.; Langhans, S. D.; Doering, M.; Tanner, C.; Uehlinger, U.

2005-05-01

215

Leaching the Poison--The Importance of Process and Partnership in Working with Yolngu  

ERIC Educational Resources Information Center

The popular construction of rural places as "white" spaces has significant repercussions for ethnic, Indigenous and "other" groups who do not always fit within prescribed dominant processes. This paper provides new insights for rural scholarship through an engagement with Indigenous specific experiences of governance and decision making in rural…

Marika, Rarriwuy; Yunupingu, Yalmay; Marika-Mununggiritj, Raymattja; Muller, Samantha

2009-01-01

216

The Importance of Cognitive Processing to Adjustment in the 1st Year Following Amputation  

Microsoft Academic Search

Objective: To describe depressive symptoms, posttraumatic stress disorder (PTSD), and posttraumatic growth at 6 and 12 months following amputation and to explore differences by demographic variables and cognitive processing of trauma. Participants: 83 adults with newly acquired limb loss. Setting: Two large metropolitan hospitals. Main Outcome Measures: The Patient Health Questionnaire depression module, PTSD Checklist, and Posttraumatic Growth Inventory. Results:

Lori F. Phelps; Rhonda M. Williams; Katherine A. Raichle; Aaron P. Turner; Dawn M. Ehde

2008-01-01

217

Importance of Industrial Design and its collaboration process with Engineering Design  

Microsoft Academic Search

While there are Industrial Design (ID) centric living commodities like home electric appliances in one hand and Engineering Design (ED) centric industrial goods like automotive parts in another, Engineering Designer (EDer) and Industrial Designer (IDer) collaborate in the development process of office equipment such as copier and facsimile that is positioned in between two types of products. Meanwhile, management strategy

Kazuhide Sugiyama; Hiroshi Osada

2011-01-01

218

Educating and Involving Parents in the Response to Intervention Process: The School's Important Role  

ERIC Educational Resources Information Center

Parents are encountering a new system that addresses struggling learners. This system is called "response to intervention" or "RTI." Schools are using this philosophy and process to direct choices about school curriculum, ongoing assessment procedures, and decisions about special education services. One positive result of the RTI system is that…

Byrd, E. Stephen

2011-01-01

219

Untangling the influences of unmodeled evolutionary processes on phylogenetic signal in a forensically important HIV-1 transmission cluster.  

PubMed

Stochastic models of sequence evolution have been developed to reflect many biologically important processes, allowing for accurate phylogenetic reconstruction when an appropriate model is selected. However, commonly used models do not incorporate several potentially important biological processes. Spurious phylogenetic inference may result if these processes play an important role in the evolution of a dataset yet are not incorporated into assumed models. Few studies have attempted to assess the relative importance of multiple processes in producing spurious inferences. The application of phylogenetic methods to infer the source of HIV-1 transmission clusters depends upon accurate phylogenetic results, yet there are several relevant unmodeled biological processes (e.g., recombination and convergence) that may cause complications. Here, through analyses of HIV-1 env sequences from a small, forensically important transmission cluster, we tease apart the impact of these processes and present evidence suggesting that convergent evolution and high rates of insertions and deletions (causing alignment uncertainty) led to spurious phylogenetic signal with forensic relevance. Previous analyses show paraphyly of HIV-1 lineages sampled from an individual who, based on non-phylogenetic evidence, had never acted as a source of infection for others in this transmission cluster. If true, this pattern calls into question assumptions underlying phylogenetic approaches to source and recipient identification. By systematically assessing the contribution of different unmodeled processes, we demonstrate that removal of sites likely influenced by strong positive selection both reduces the alignment-wide signal supporting paraphyly of viruses sampled from this individual and eliminates support for the effects of recombination. Additionally, the removal of ambiguously aligned sites alters strongly supported relationships among viruses sampled from different individuals. These observations highlight the need to jointly consider multiple unmodeled evolutionary processes and motivate a phylogenomic perspective when inferring viral transmission histories. PMID:24589520

Doyle, Vinson P; Andersen, John J; Nelson, Bradley J; Metzker, Michael L; Brown, Jeremy M

2014-06-01

220

Nickel ferrite aerogels with monodisperse nanoscale building blocks--the importance of processing temperature and atmosphere.  

PubMed

Using two-step (air/argon) thermal processing, sol-gel-derived nickel-iron oxide aerogels are transformed into monodisperse, networked nanocrystalline magnetic oxides of NiFe(2)O(4) with particle diameters that can be ripened with increasing temperature under argon to 4.6, 6.4, and 8.8 nm. Processing in air alone yields poorly crystalline materials; heating in argon alone leads to single phase, but diversiform, polydisperse NiFe(2)O(4), which hampers interpretation of the magnetic properties of the nanoarchitectures. The two-step method yields an improved model system to study magnetic effects as a function of size on the nanoscale while maintaining the particles within the size regime of single domain magnets, as networked building blocks, not agglomerates, and without stabilizing ligands capping the surface. PMID:19206611

Pettigrew, Katherine A; Long, Jeffrey W; Carpenter, Everett E; Baker, Colin C; Lytle, Justin C; Chervin, Christopher N; Logan, Michael S; Stroud, Rhonda M; Rolison, Debra R

2008-04-01

221

Are multiple parton interactions important at high energies? New types of hadrons production processes  

E-print Network

Hadrons interaction at high energies is carried out by one color gluon exchange. All quarks and gluons contained in colliding hadrons take part in interaction and production of particles. The contribution of multiple parton interactions is negligible. Multiple hadrons production at high energies occurs only in three types of processes. The first process is hadrons production in gluon string, the second is hadrons production in two quark strings and the third is hadrons production in three quark strings. In proton-proton interaction production of only gluon string and two quark strings is possible. In proton-antiproton interaction production of gluon string, two quark strings and three quark strings is possible. Therefore multiplicity distributions in proton-proton and proton-antiproton interactions are different.

V. A. Abramovsky

2009-11-25

222

Towards sustainability in the water sector – The importance of human actors and processes of social learning  

Microsoft Academic Search

.   Current regimes in resource management are often unsustainable as judged by ecological, economic and social criteria. Many\\u000a technological resource management regimes are inflexible and not built to adapt to changes in environmental, economic or social\\u000a circumstances. This inflexibility poses problems in a world characterized by fast change. The water sector is currently undergoing\\u000a major processes of transformation at local,

Claudia Pahl-Wostl

2002-01-01

223

The Importance of Non-Data Touching Processing Overheads in TCP\\/IP  

Microsoft Academic Search

We present detailed measurements of various processing overheads of the TCP\\/IP and UDP\\/IP protocol stacks on a DECstation 5000\\/200 running the Ultrix 4.2a operating system. These overheads include data-touching operations, such as the checksum computation and data movement, which are well known to be major time consumers. In this study, we also considered overheads due to non-data touching operations, such

Jonathan Kay; Joseph Pasquale

1993-01-01

224

The Importance of Microphysical Processes in the Magnetosphere-Ionosphere System  

NASA Astrophysics Data System (ADS)

The effects of low-altitude collisionless energy conversion on global aspects of the magnetosphere-ionosphere (M-I) interaction are considered. Electromagnetic power flowing from the magnetosphere into auroral and cusp regions is converted, via an abundance of collisionless plasma processes, to beams of precipitating electrons and transversely accelerated ions (TAIs), principally O+ due to its larger gyroradius. Electron precipitation gates ionospheric Joule dissipation by modifying the ionospheric conductance. Depending on its energy spectrum and flux, precipitation also increases the scale height of the ionosphere, thereby enhancing the source population of TAIs. TAIs become ionospheric outflows under the action of the mirror force. Outflows have the capacity to inflate and stretch the nightside plasmasheet and modify the nightside reconnection rate. Their effects seem to be integral in determining (in global simulations) whether the M-I system, for steady solar wind (SW) driving, settles into a steady magnetospheric convection mode or a sawtooth mode. By enhancing the asymmetric ring current, outflows also effectively change the shape of the magnetospheric boundary, which changes the solar wind - magnetosphere interaction, the dayside reconnection potential, the cross polar cap potential, ionospheric Joule dissipation and the current-voltage characteristics of the SW-M-I interaction. From a dynamical system perspective, one is tempted to trace the causal chain from solar wind and magnetotail dynamos, to the resulting electromagnetic power flows that deposit energy at low altitude, to conversion of this energy to particle beams and heat, and, then, to ascribe observed morphologies of these processes to the distributions of the dynamos. However, it will be shown using global simulation experiments that the morphology and dynamics and, to some extent, the power derived from the dynamos is determined as much by the M-I interaction as by the SW-M interaction. This behavior is indicative of a geospace system exhibiting strong coupling and feedback among its internal elements. That the products of energy conversion (electron beams and ion flows) enabled by local, microphysical processes feedback into global system behavior is also indicative of a scale-interactive system: Large-scale processes regulate microprocesses, which, in turn, regulate the large-scale processes.

Lotko, W.

2012-12-01

225

Laboratory studies of atomic collision processes of importance in planetary atmospheres  

NASA Technical Reports Server (NTRS)

A series of differential cross sections for angular scattering and charge transfer was measured. These studies employ position-sensitive detectors (PSD's) to collect collision products scattered over a wide range of angles; and the research program includes investigation of differential cross sections for total angular scattering, charge transfer, stripping, and other collisions. All of these processes can be studied with the same basic apparatus, but minor modifications in the equipment details and in the data acquisition programs and techniques are required for each individual experiment.

Stebbings, R. F.; Smith, K.

1985-01-01

226

Competition between diffusion and fragmentation: an important evolutionary process of nature.  

PubMed

We investigate systems of nature where the common physical processes diffusion and fragmentation compete. We derive a rate equation for the size distribution of fragments. The equation leads to a third order differential equation which we solve exactly in terms of Bessel functions. The stationary state is a universal Bessel distribution described by one parameter, which fits perfectly experimental data from two very different systems of nature, namely, the distribution of ice-crystal sizes from the Greenland ice sheet and the length distribution of alpha helices in proteins. PMID:14754071

Ferkinghoff-Borg, Jesper; Jensen, Mogens H; Mathiesen, Joachim; Olesen, Poul; Sneppen, Kim

2003-12-31

227

Cold plasma processing of local planetary ores for oxygen and metallurgically important metals  

NASA Technical Reports Server (NTRS)

The utilization of a cold or nonequilibrium plasma in chlorination processing is discussed. Titanium dioxide (TiO2) was successfully chlorinated at temperatures between 700 and 900 C without the aid of carbon. In addition to these initial experiments, a technique was developed for determining the temperature of a specimen in a plasma. Development of that technique has required evaluating the emissivity of TiO2, ZrO2, and FeOTiO2 and analyzing the specimen temperature in a plasma as a function of both power absorbed by the plasma and the pressure of the plasma. The mass spectrometer was also calibrated with TiCl4 and CCl4 vapor.

Lynch, D. C.; Bullard, D.; Ortega, R.

1991-01-01

228

Importance of Translational Entropy of Water in Biological Self-Assembly Processes like Protein Folding  

PubMed Central

We briefly review our studies on the folding/unfolding mechanisms of proteins. In biological self-assembly processes such as protein folding, the number of accessible translational configurations of water in the system increases greatly, leading to a large gain in the water entropy. The usual view looking at only the water in the close vicinity of the protein surface is capable of elucidating neither the large entropic gain upon apoplastocyanin folding, which has recently been found in a novel experimental study, nor the pressure and cold denaturation. With the emphasis on the translational entropy of water, we are presently constructing a reliable method for predicting the native structure of a protein from its amino-acid sequence. PMID:19399238

Kinoshita, Masahiro

2009-01-01

229

The Importance of Water for High Fidelity Information Processing and for Life  

NASA Technical Reports Server (NTRS)

Is water an absolute prerequisite for life? Life depends on a variety of non-covalent interactions among molecules, the nature of which is determined as much by the solvent in which they occur as by the molecules themselves. Catalysis and information processing, two essential functions of life, require non-covalent molecular recognition with very high specificity. For example, to correctly reproduce a string consisting of 600,000 units of information (e.g ., 600 kilobases, equivalent to the genome of the smallest free living terrestrial organisms) with a 90% success rate requires specificity > 107 : 1 for the target molecule vs. incorrect alternatives. Such specificity requires (i) that the correct molecular association is energetically stabilized by at least 40 kJ/mol relative to alternatives, and (ii) that the system is able to sample among possible states (alternative molecular associations) rapidly enough to allow the system to fall under thermodynamic control and express the energetic stabilization. We argue that electrostatic interactions are required to confer the necessary energetic stabilization vs. a large library of molecular alternatives, and that a solvent with polarity and dielectric properties comparable to water is required for the system to sample among possible states and express thermodynamic control. Electrostatic associations can be made in non-polar solvents, but the resulting complexes are too stable to be "unmade" with sufficient frequency to confer thermodynamic control on the system. An electrostatic molecular complex representing 3 units of information (e.g., 3 base pairs) with specificity > 107 per unit has a stability in non-polar solvent comparable to that of a carbon-carbon bond at room temperature. These considerations suggest that water, or a solvent with properties very like water, is necessary to support high-fidelity information processing, and can therefore be considered a critical prerequisite for life.

Hoehler, Tori M.; Pohorille, Andrew

2011-01-01

230

Stable Isotope Signatures Illustrate the Importance of Fog and Cloud Water in Ecohydrological Processes  

NASA Astrophysics Data System (ADS)

Fog and cloud water, when part of an ecohydrologically significant local climate pattern, can contribute to stream flow, groundwater recharge, soil moisture, and plant uptake in coastal and mountain watersheds. Stable isotopes of water, 18O and 2H, can be used to quantify different sources of precipitation, and to assess the role of fog or cloud water within the ecosystem. Fog and cloud water are usually enriched in 18O and 2H relative to rain at the same site, explained in part by the effect of temperature on stable isotope fractionation - relatively higher temperatures close to the land surface tend to keep the vapor/condensed phase system from evolving to lower isotopic ratios. Land immersed in coastal fog or orographic clouds receives droplet sizes from fog to light rain. Isotopic composition of fog-sized droplets may be similar to the small raindrops, so stable isotopes reflect precipitation source to a greater extent than precipitation size. As a result, isotopic water balance determinations can show higher amounts of cloud water than determinations using fog collectors, canopy water balances, eddy covariance, and other methods. Examples from Hawaii and Puerto Rico illustrate the use of stable isotope methods in cloud forest studies. On East Maui in Hawaii, clouds intercept the mountain slopes between 600 and 2200 m on both windward and leeward sides of the island. Puerto Rico's eastern mountains receive cloud water input at their highest altitudes, between 900-1100 m. At all sites, stable isotopes of cloud water and rain were measured using passive fog and rain collectors; weather stations and throughfall gages provided additional data. Estimates of cloud water as a fraction of total precipitation input from isotopic mixing models and the canopy water balance calculations were 29% and 15%, respectively, on leeward Maui and 27% and 32% on windward Maui. Cloud water input in the Luquillo Mountains of Puerto Rico was estimated to be 45-56% of total precipitation from isotope mixing model results, compared with 10-16% from studies using physical methods. Determination of cloud height and atmospheric temperature for individual rain events and for weekly rain samples confirmed the isotopic signature of orographic cloud water and helped quantify the importance of that weather pattern to the forest ecohydrology. Isotopic composition of stream water indicated that orographic cloud water is an important component of headwater streamflow year-round (62% in Puerto Rico, 37% in Maui). In Puerto Rico, quantifying the isotopic signatures of rain from different weather patterns showed that streams had a higher proportion of orographic precipitation than the bulk rainfall, highlighting the importance of low-intensity cloud water precipitation in maintaining baseflow. On Maui, ohia lehua (Metrosideros polymorpha) xylem water isotopic composition indicated different water use strategies by the trees at the windward and leeward sites, which had different precipitation regimes. Isotope analyses work very well for tracing the pathways of cloud water within watersheds, and results can lead to a better understanding of the role of fog and cloud water in coastal and mountain ecosystems.

Scholl, M. A.

2012-12-01

231

The Emerging Medical and Geological Association  

PubMed Central

The impact on human health by natural materials such as water, rocks, and minerals has been known for thousands of years but there have been few systematic, multidisciplinary studies on the relationship between geologic materials and processes and human health (the field of study commonly referred to as medical geology). In the past few years, however, there has been a resurgence of interest in medical geology. Geoscientists working with medical researchers and public health scientists have made important contributions to understanding novel exposure pathways and causes of a wide range of environmental health problems such as: exposure to toxic levels of trace essential and non-essential elements such as arsenic and mercury; trace element deficiencies; exposure to natural dusts and to radioactivity; naturally occurring organic compounds in drinking water; volcanic emissions, etc. By linking with biomedical/public health researchers geoscientists are finally taking advantage of this age-old opportunity to help mitigate environmental health problems. The International Medical Geology Association has recently been formed to support this effort. PMID:16555612

Finkelman, Robert B; Centeno, Jose A; Selinus, Olle

2005-01-01

232

Geologic Map and Eruptive History of Veniaminof Volcano Record Aleutian Arc Processing of Mantle-Derived Melts  

NASA Astrophysics Data System (ADS)

Mount Veniaminof, one of the largest volcanoes in the Aleutian arc, has a basal diameter of ~40 km, a volume of ~350 km3, an 8-km-diameter ice-filled caldera, and an active intracaldera cone. The geology of this tholeiitic basalt-to-dacite volcano has been mapped at 1:50,000 scale. Over 100 Quaternary volcanic map units are characterized by 600 chemical analyses of rocks and nearly 100 40Ar/39Ar and K-Ar ages. Throughout its history, lava flows from Veniaminof recorded alternately ice/melt-water chilling or ice-free conditions that are consistent with independent paleoclimatic records. Exposures from deep glacial valleys to the caldera rim reveal a long history dominated by basalt and basaltic andesite from ?260 ka to 150 ka that includes compositions as primitive as 9.4% MgO and 130 ppm Ni at 50% SiO2. Basaltic andesite, common throughout Veniaminof's history, has low compatible-element contents that indicate an origin by fractionation of basaltic magma. Repeated eruption of more differentiated melts from a shallow intrusive complex, represented by granodiorite (crystallized dacitic magma) and cumulate gabbro and diorite xenoliths in pyroclastic deposits, has featured virtually aphyric andesite since 150 ka and dacite (to 69.5% SiO2) beginning ~110 ka. These variably differentiated liquids segregated from crystal mush, possibly by gas-driven filter pressing, and commonly vented but also solidified at depth. A large composite cone was present at least as early as 200 ka. Although asymmetric edifice morphology hints at early sector collapse to the southeast, coeval vents on northwest and southeast flanks and the distribution of extensive lava units indicate that a large cone (again) was present by 120 ka. Flank eruption of a wide variety of Veniaminof magmas was common from plate-convergence-parallel northwest-trending fissures from at least as early as ca. 80 ka. At 56 ka and at 46 ka, voluminous dacite lava erupted on both northwest and southeast flanks. A dacitic pyroclastic-flow deposit on the northwest flank, sandwiched between 46±1-ka dacite and 28±4-ka andesite lava flows, may record early caldera collapse as also evidenced by thick 33±6-ka ice-chilled dacite lava that must have banked against ice in a depression spatially coincident with the northwest part of the present caldera. The modern caldera formed, or was enlarged, during two voluminous Holocene explosive eruptions of crystal-poor andesite ~3700 14C yr BP and >4700 14C yr BP (Miller et al., 2002 Fall AGU, V11A-1376) that emplaced pyroclastic-flow deposits on Veniaminof's flanks and in surrounding valleys. Frequent eruption from shallow reservoirs may suppress accumulation of more than a few km3 of dacitic magma at Veniaminof.

Bacon, C. R.; Sisson, T. W.; Calvert, A. T.; Nye, C. J.

2009-12-01

233

Color applied to printing graphic design: the importance of lighting in the color perception and specification process  

Microsoft Academic Search

This work approaches the importance of lighting in the process of chromatic categorization, selection and specification applied to the printed media. Some concepts regarding lighting are presented, such as color temperature, color appearance and color rendering index. Finally, stands out the necessity to evaluate the samples under standard lighting conditions regarding the environment where the final product will be exposed.

Berenice S. Goncalves; Alice C. Pereira; Fernando R. Pereira

2002-01-01

234

The importance of group identity processes in involvement in social movement organizations: the case of Attac France and Germany  

Microsoft Academic Search

This research evaluates the relative and absolute importance of group identity processes in an individual's decision to become and remain active in a social movement organization (SMO). Mainly through interview research with the members of Attac Germany and France, I discover that the presence of a comfortable and communicative group atmosphere is a necessary, but insufficient, condition for movement activity.

Daniel Stockemer

2012-01-01

235

The Importance Of Increase Of The Process Of Innovation And Technology Transfer To Teaching Academic And Industries In Developing Countries  

Microsoft Academic Search

Within the context of globalization and internationalization of the economy and markets the advances in technology have come to be recognized as the most important single factor contributing to economic growth. The fast development of technologies, combined with increased global and more stringent customer demands strongly pressurizes companies to improve the pace and quality of product and process innovation. Therefore,

Mirella Prates Marchiori

236

Leeds Internship Programme Internships are an important part of the learning process for many of our students. Through  

E-print Network

Leeds Internship Programme Internships are an important part of the learning process for many of our students. Through Campaign funding for the Leeds Internship Programme, we will offer more of our the funds to pay for an internship. Equally, students who would be ideally suited to such an opportunity

Haase, Markus

237

Why Is Evolution Important? The discovery and understanding of the processes of evolution represent one of the most  

E-print Network

#12;Why Is Evolution Important? The discovery and understanding of the processes of evolution represent one of the most powerful achievements in the history of science. Evolution successfully explains education in our schools is being undermined by efforts to introduce non-scientific concepts about evolution

Lanterman, Aaron

238

Please Note: The University's Financial Processing Section will communicate important student financial information by email and or text with individual  

E-print Network

reserves the right not to re-enrol any student who has outstanding debt to the University from a previousPlease Note: The University's Financial Processing Section will communicate important student financial information by email and or text with individual students using the relevant student's University

239

Medical Geology in Africa  

Microsoft Academic Search

\\u000a A large body of evidence points to significant health effects resulting from our interactions with the physical environment\\u000a and we continue to recognise connections between geological materials and processes and human and animal disease. In Africa,\\u000a these relationships have been observed for many years, but only recently have any real attempts been made to formalise their\\u000a study. Africa is a

T. C. Davies

240

Principles of nuclear geology  

SciTech Connect

This book treats the basic principles of nuclear physics and the mineralogy, geochemistry, distribution and ore deposits of uranium and thorium. The application of nuclear methodology in radiogenic heat and thermal regime of the earth, radiometric prospecting, isotopic age dating, stable isotopes and cosmic-ray produced isotopes is covered. Geological processes, such as metamorphic chronology, petrogenesis, groundwater movement, and sedimentation rate are focussed on.

Aswathanarayana, U.

1985-01-01

241

Plasma wall interaction: Important ion induced surface processes and strategy of the EU Task Force  

NASA Astrophysics Data System (ADS)

In future thermo-nuclear fusion devices, such as ITER (International Thermonuclear Experimental Reactor), the interaction of the plasma with surrounding materials in the vacuum vessel constitutes one of the main remaining engineering problems. The choice of materials is a crucial point, which will determine issues such as the plasma facing components lifetime before refurbishment or the tritium inventory build up in the vessel, which should be limited for safety reasons. In order to tackle these issues, the European Task Force on Plasma-Wall Interaction has been implemented in the frame of EFDA (European Fusion Agreement) in the fall 2002 with the aim "to provide ITER with information concerning lifetime-expectations of the divertor target plates and tritium inventory build-up rates in the foreseen starting configuration and to suggest improvements, including material changes, which could be implemented at an appropriate stage." The EU-PWI-TF brings together the efforts of 24 European associations in the following fields of investigation: Material erosion and transport in tokamaks. Tritium inventory and removal. Transient heat loads on plasma facing components. Dust production and removal. Associated modelling and diagnostic development. This paper will present the organisation of the EU-PWI-TF. It will provide examples for the multitude of surface processes in Plasma-Wall Interaction and present the status of knowledge concerning material erosion and hydrogen retention for the choice of ITER materials (Beryllium, Carbon and Tungsten).

Roth, Joachim; Tsitrone, Emmanuelle; Loarte, Alberto

2007-05-01

242

Illinois State Geological Survey  

NSDL National Science Digital Library

The Illinois State Geological Survey (ISGS) homepage provides information on geologic mapping, earthquakes, fossils, groundwater, wetlands, glacial geology, bedrock geology, and Lake Michigan geology. Educational materials include field trip guides, short publications on Illinois geology for students and teachers, online tours, single-page maps, and a geologic column. Other materials include databases and collections of GIS data, well records, drill cores, and mining information; a bibliography of Illinois geology; online maps and data; and information on water and land use, resource development, and geologic hazards.

243

Results from an International Simulation Study on Coupled Thermal,Hydrological, and Mechanical (THM) Processes near Geological NuclearWaste Repositories  

SciTech Connect

As part of the ongoing international DECOVALEX project, four research teams used five different models to simulate coupled thermal, hydrological, and mechanical (THM) processes near waste emplacement drifts of geological nuclear waste repositories. The simulations were conducted for two generic repository types, one with open and the other with back-filled repository drifts, under higher and lower postclosure temperatures, respectively. In the completed first model inception phase of the project, a good agreement was achieved between the research teams in calculating THM responses for both repository types, although some disagreement in hydrological responses is currently being resolved. In particular, good agreement in the basic thermal-mechanical responses was achieved for both repository types, even though some teams used relatively simplified thermal-elastic heat-conduction models that neglected complex near-field thermal-hydrological processes. The good agreement between the complex and simplified process models indicates that the basic thermal-mechanical responses can be predicted with a relatively high confidence level.

Rutqvist, Jonny; Rutqvist, J.; Barr, D.; Birkholzer, J.T.; Chijimatsu, M.; Kolditz, O.; Liu, Q.-S; Oda, Y.; Wang, W.; Zhang, C.-Y.

2007-10-23

244

Hydraulic-gas transient processes within the overall phenomenological evolution of the French HLW deep geological disposal: current knowledge in PA perspective  

NASA Astrophysics Data System (ADS)

Because of the creation of the disposal underground facilities, then of the ventilation of whole or part of these facilities during operating period, and finally of hydrogen production, mainly by anoxic corrosion of metallic components, in post-closure period, the phenomenological evolution of a radwaste deep geological repository and its surrounding host rock will be characterized by an hydraulic and gas transient phase until the overall system reach an equilibrium state. This paper presents the analysis of this transient phase carried out in France within the framework of the feasibility study of a HLW and ILLW deep geological disposal in the Callovo-Oxfordian clay layer (Meuse/Haute Marne site) (Dossier 2005 Argile) according to the current state of knowledge: the broad outlines of the expected evolution are described in time and space from operating period to post closure period, taking into consideration the studied design concept (overall architecture, disposal zones, disposal modules, disposal cells, various types of waste, operating conditions…). More particularly for hydrogen, emphasis is focused on space and time organization of production and migration, in particular the various sources of production, the various pathways of migrations and interactions with hydraulics. Although the description is supported by a sound data base on hydraulic and gas production and migration (clay media, engineered materials, corrosion, radiolysis…) and numerical calculations at different scales of time and space, uncertainties exist both in phenomenology (Hydrogen production mechanisms, Hydrogen migration mechanisms in clay media, modeling of mechanisms, values of parameters…) and in simulation (in particular limitations to achieve the various time and space scales and some couplings). So deviations of the expected evolution are discussed. Results of this analysis show that the hydraulic and gas transient phase may present a complex organization in time and space, and may relate to significant scales of time, several tens of thousands to one hundred of thousands years. So the hydraulic - gas transient has to be put in prospective for other processes involved in the phenomenological evolution (thermal, mechanics and chemical processes), so to evaluate if there are the interactions/couplings or not between all these processes in time and space. In particular effect of hydraulic - gas processes on degradation of waste, release and then migration of radionuclide are discussed in PA perspective. In conclusion, ways of progress to describe the hydraulic and gas transient phase are indicated, in view of the demand of a licensing authorization of a repository in 2014.

Wendling, J.; Plas, F.

2009-04-01

245

Brines in Crustal Processes: Important Roles Inferred From Experimental Studies (Invited)  

NASA Astrophysics Data System (ADS)

Concentrated salt solutions are increasingly implicated as active agents in many fluid-mediated deep- and mid-crust processes, including rock-melting, charnockitic alteration, trace-element depletion and enrichment, regional metasomatism including dehydration and rehydration, albitization, deep-crustal oxidation, and formation of economic mineral deposits. Unique properties of saline aqueous fluids at high P and T, recently revealed by experimental work, provide new explanations for these metasomatic features and encourage further search for a brine connection in other outstanding problems of metamorphism. Specific properties of high P-T NaCl solutions favorable for deep-crustal metasomatism are high solubility for some rock-forming components, especially CaO and FeO, even at high salt concentration, very low H2O activity as a consequence of pressure-induced dissociation, allowing compatibility with anhydrous (granulite facies) mineral assemblages, and high ability to infiltrate mineral grain boundaries. The high affinity of alkali chloride brines for CaO can explain trace element mobility in high grade metamorphism, by virtue of the high solubility of apatite, and the puzzling phenomenon of subsolidus charnockitic alteration, as in South India, in which orthopyroxene is formed from the incongruent dissolution of calcic amphibole. The great pressure effect on lowering H2O activity in concentrated pore-fluid brines causes fluid-present melting points of crustal rocks to swerve sharply to higher temperatures with increasing depth, in contrast to the behavior in the presence of pure H2O. This fact could account for the formation of swarms of granite intrusions in shear-zone-related settings, such as the Caledonide granites of Scotland and northern Ireland. It is postulated that salty solutions of deep-seated origin inhibit melting as they rise through the lower crust, but induce large-scale melting at mid-crust levels because of increase of H2O activity by release of pressure. Sulfide ore deposits of various kinds including the porphyry Cu-Mo ores can be explained by the action of CaSO4-bearing brines of magmatic origin. The changes in composition of Cl-rich fluids in contact with feldspathic rocks with falling temperature could explain regional albitization in the lower grade portions of the great Precambrian metamorphic belts such as the Limpopo Belt of South Africa. Of the several possible sources of concentrated salty fluids, the most appealing for wide application is effluents from volatile-rich basaltic intrusions, which also provide heat for regional metamorphism and temperature gradients convenient for geochemical segregation and ore mineral accumulation.

Newton, R. C.; Manning, C. E.

2009-12-01

246

Do geological or climatic processes drive speciation in dynamic archipelagos? The tempo and mode of diversification in Southeast Asian shrews  

E-print Network

distribution of terrestrial habitats has been altered extensively through time (Heaney 1985; Hall 1998; Voris 2000; Bird et al. 2005). The processes of volcanic uplift and repeated sea level fluctuations represent potential mechanisms promoting evolutionary... et al. 1998; Hutterer 2005; Dubey et al. 2007, 2008). Dubey et al. (2007) estimated the divergence of African from Eurasian Cro- cidura at 5.4–10.7 million years ago (mya), thus the entire history of shrew evolution in Southeast Asia likely took place...

Esselstyn, Jacob Aaron; Timm, Robert M.; Brown, Rafe M.

2009-10-01

247

Results from an International Simulation Study on Couples Thermal, Hydrological, and Mechanical (THM) Processes Near Geological Nuclear Waste Repositories  

SciTech Connect

As part of the ongoing international code comparison project DECOVALEX, four research teams used five different models to simulate coupled thermal, hydrological, and mechanical (THM) processes near underground waste emplacement drifts. The simulations were conducted for two generic repository types with open or back-filled repository drifts under higher and lower post-closure temperature, respectively. In the completed first model inception phase of the project, a good agreement was achieved between the research teams in calculating THM responses for both repository types, although some disagreement in hydrological responses are currently being resolved. Good agreement in the basic thermal-mechanical responses was achieved for both repository types, even with some teams using relatively simplified thermal-elastic heat-conduction models that neglect complex near-field thermal-hydrological processes. The good agreement between the complex and simplified (and well-known) process models indicates that the basic thermal-mechanical responses can be predicted with a relatively high confidence level. The research teams have now moved on to the second phase of the project, the analysis of THM-induced permanent (irreversible) changes and the impact of those changes on the fluid flow field near an emplacement drift.

J. Rutqvist; J.T> Birkholzer; M. Chijimatsu; O. Kolditz; Q.S. Liu; Y. Oda; W. Wang; C.Y. Zhang

2006-02-01

248

Estimation of flow parameters applying hydro- geological area information  

Microsoft Academic Search

In the past years many researchers have stressed the important role of geology on river flows and have pointed out in particular the problem of developing a numerical index of geology. The objective of this paper is to present an approach to developing a geological index. The method is based on a classification scheme including both basin geology and hydrogeological

S. DEMUTH; I. HAGEMANN

249

Geological Survey research, 1975  

USGS Publications Warehouse

'Geological Survey Research 1975 ' is the 16th annual synopsis of the results of U.S. Geological Survey investigations. These studies are largely directed toward the development of knowledge that will assist the Nation to use and conserve the land and its physical resources wisely. They are wide ranging in scope and deal with almost every facet of solid-earth science and fact finding. Many of the studies are continuations of investigations that have been in progress for several years. But others reflect the increased attention being given to problems that have assumed greater importance in recent years--problems relating to mineral fuels and mineral resources, water quality, environmental impact of mineral resources, land-use analysis, earthquake hazards reduction, subsidence, and the applications of LANDSAT data, to cite a few examples. (Woodard-USGS)

1975-01-01

250

Spirit's Traverse to the Columbia Hills: Systematic Variations in Clast Morphometry and Texture of Pebble to Cobble Sized Clasts, With Implications for Geological Processes and History  

NASA Astrophysics Data System (ADS)

During the course of Spirit's traverse from the Columbia Memorial Station to the Columbia Hills a systematic set of PanCam observations called the clast survey were taken to look for evidence of fluvial activity affecting the morphology of pebble to cobble sized material. These PanCam observations employed a single frame, blue filter shot at 4 bits/pixel looking just above the deck in front of the rover at an angle centering the frame at -72 degrees. These images were taken at 42 sites during the course of the traverse from the landing site to the base of the Columbia Hills. This traverse encountered approximately 6 different geological units that were inferred from orbital data including thermal inertia estimates from Odyssey's THEMIS instrument, as well as geomorphic features observed by the Mars Global Surveyor's Mars Orbital Camera (MOC). Clast survey observations enabled quantification of changes in the size, roundness, sphericity, sorting, density (clasts/meter2), dispersion (nearest neighbor distances) and vesicularity of clasts over the course of Spirit's traverse across the plains to the base of the Columbia Hills. The overall goal was to look for trends in the above parameters that could allow an objective discrimination between basic erosional/depositional processes, including impact, fluvial, debris flow, glacial, and aeolian. To assist the interpretation of this data set, a variety of potential terrestrial analogs were investigated using the same clast survey parameters that were employed during Spirit's traverse. Each terrestrial analog was selected to represent an end member geologic process that could have shaped local clast distribution and morphology. These data sets were analyzed using SAS/STAT statistical software, employing Principle Component Analysis (PCA) to reduce the dimensionality of the data set, focus attention on the relationships between independent variables, and to identify factors that, taken together, could provide an objective basis for discriminating between geological processes. During the course of the traverse, significant changes were observed in clast size when moving from the continuous ejecta blanket of Bonneville crater (high thermal inertia) onto the intercrater plains (low thermal inertia). However, this trend was not apparent when crossing the continuous ejecta of two smaller craters, Lahontan and Missoula. In fact, clast sizes for these two craters compared more closely to the smooth intercrater plains unit previously mapped from orbit. Over the traverse, significant variations were observed in the distribution of vesicular clasts and in clast density. Changes in vesicularity are interpreted as relfecting local changes in the distribution and impact excavation depths of buried lava flow surfaces. Observed trends in clast size correlated well with thermal inertia values, as estimated from orbital (THEMIS) data. Over the course of the traverse, clast roundness and sorting remained remarkably consistent, with mean estimates falling between sub-angular to subrounded, and poorly sorted. These observations do not support previous suggestions of water-based depositional systems (fluvial, debris flow, or glacial processes) at the Spirit landing site, based on orbital data. Instead, observed trends are consistent with a heavily cratered, wind modified ejecta surface, developed above a flow-dominated basaltic volcanic sequence.

Grant, F. D.; Farmer, J. D.; Team, M.

2005-05-01

251

Thermal Conduction - A Tool for Exploring Geological Processes on the Earth and Other Bodies in our Solar System  

NSDL National Science Digital Library

Thermal conduction is a fundamental physical process, one which controls many aspects of the volcanic and tectonic evolution of bodies within our solar system. Using transmission of thermal energy through the crust of the Earth as an initial, physically intuitive conceptual model, the module's background material will (a) help students deduce the thermal conduction equation-a second order differential which can be constructed from first principles, (b) evaluate volume-adjusted conduction incorporating internal heat generation and temperature change, and (c) explore special forms of the equation such as steady state conduction and thermal diffusion.

Grosfils, Eric

252

Geologic Technician New Curriculum  

ERIC Educational Resources Information Center

Describes a developing two-year geologic technician program at Bakersfield College in which a student may major in five areas - geologic drafting, land and legal, geologic assistant, engineering or paleontology. (RR)

Karp, Stanley E.

1970-01-01

253

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.

254

Geology of Wisconsin  

NSDL National Science Digital Library

This site contains geologic maps of Wisconsin including relief and topography maps; maps of the bedrock geology and elevation, Pleistocene geology, thickness of unconsolidated deposits, and soils; and atlases of geologic history. There is information on: rock types, Paleozoic formations, and the Pleistocene and Precambrian history of Wisconsin; how to obtain a geologic map of personal property; the Niagara Escarpment; castellated mounds; geologic field localities; and unusual weather events in Wisconsin. There is also a data table on earthquakes in Wisconsin.

Dutch, Steven

1997-09-10

255

A SxIP motif interaction at the microtubule plus end is important for processive retrograde axonal transport.  

PubMed

The retrograde transport of endosomes within axons proceeds with remarkable uniformity despite having to navigate a discontinuous microtubule network. The mechanisms through which this navigation is achieved remain elusive. In this report, we demonstrate that access of SxIP motif proteins, such as BPAG1n4, to the microtubule plus end is important for the maintenance of processive and sustained retrograde transport along the axon. Disruption of this interaction at the microtubule plus end significantly increases endosome stalling. Our study thus provides strong insight into the role of plus-end-binding proteins in the processive navigation of cargo within the axon. PMID:24687423

Kapur, Mridu; Maloney, Michael T; Wang, Wei; Chen, Xinyu; Millan, Ivan; Mooney, Trevor; Yang, Jie; Yang, Yanmin

2014-10-01

256

Geological structure, recharge processes and underground drainage of a glacierised karst aquifer system, Tsanfleuron-Sanetsch, Swiss Alps  

NASA Astrophysics Data System (ADS)

The relationships between stratigraphic and tectonic setting, recharge processes and underground drainage of the glacierised karst aquifer system ‘Tsanfleuron-Sanetsch’ in the Swiss Alps have been studied by means of various methods, particularly tracer tests (19 injections). The area belongs to the Helvetic nappes and consists of Jurassic to Palaeogene sedimentary rocks. Strata are folded and form a regional anticlinorium. Cretaceous Urgonian limestone constitutes the main karst aquifer, overlain by a retreating glacier in its upper part. Polished limestone surfaces are exposed between the glacier front and the end moraine of 1855/1860 (Little Ice Age); typical alpine karrenfields can be observed further below. Results show that (1) large parts of the area are drained by the Glarey spring, which is used as a drinking water source, while marginal parts belong to the catchments of other springs; (2) groundwater flow towards the Glarey spring occurs in the main aquifer, parallel to stratification, while flow towards another spring crosses the entire stratigraphic sequence, consisting of about 800 m of marl and limestone, along deep faults that were probably enlarged by mass movements; (3) the variability of glacial meltwater production influences the shape of the tracer breakthrough curves and, consequently, flow and transport in the aquifer.

Gremaud, Vivian; Goldscheider, Nico; Savoy, Ludovic; Favre, Gérald; Masson, Henri

2009-12-01

257

A network model shows the importance of coupled processes in the microbial N cycle in the Cape Fear River Estuary  

NASA Astrophysics Data System (ADS)

Estuaries serve important ecological and economic functions including habitat provision and the removal of nutrients. Eutrophication can overwhelm the nutrient removal capacity of estuaries and poses a widely recognized threat to the health and function of these ecosystems. Denitrification and anaerobic ammonium oxidation (anammox) are microbial processes responsible for the removal of fixed nitrogen and diminish the effects of eutrophication. Both of these microbial removal processes can be influenced by direct inputs of dissolved inorganic nitrogen substrates or supported by microbial interactions with other nitrogen transforming pathways such as nitrification and dissimilatory nitrate reduction to ammonium (DNRA). The coupling of nitrogen removal pathways to other transformation pathways facilitates the removal of some forms of inorganic nitrogen; however, differentiating between direct and coupled nitrogen removal is difficult. Network modeling provides a tool to examine interactions among microbial nitrogen cycling processes and to determine the within-system history of nitrogen involved in denitrification and anammox. To examine the coupling of nitrogen cycling processes, we built a nitrogen budget mass balance network model in two adjacent 1 cm3 sections of bottom water and sediment in the oligohaline portion of the Cape Fear River Estuary, NC, USA. Pathway, flow, and environ ecological network analyses were conducted to characterize the organization of nitrogen flow in the estuary and to estimate the coupling of nitrification to denitrification and of nitrification and DNRA to anammox. Centrality analysis indicated NH4+ is the most important form of nitrogen involved in removal processes. The model analysis further suggested that direct denitrification and coupled nitrification-denitrification had similar contributions to nitrogen removal while direct anammox was dominant to coupled forms of anammox. Finally, results also indicated that partial nitrification-anammox may play an important role in anammox nitrogen removal in the Cape Fear River Estuary.

Hines, David E.; Lisa, Jessica A.; Song, Bongkeun; Tobias, Craig R.; Borrett, Stuart R.

2012-06-01

258

Colorado Geological Survey  

NSDL National Science Digital Library

The Colorado Geological Survey (CGS) is an agency of state government within the Department of Natural Resources whose mission is to help reduce the impact of geologic hazards on the citizens of Colorado, to promote the responsible economic development of mineral and mineral fuel resources, to provide geologic insight into water resources, and to provide geologic advice and information to a variety of constituencies. This site contains extensive information about Colorado geology such as maps, a geologic time scale for the state, program information, and state field trip information. This site hosts the Avalanche Information Center which contains avalanche forecasting and education center details. Publications report on geologic hazards, land use, environmental geology, mineral resources, oil, gas, coal, geologic mapping and earthquake information for the state. There are online editions of RockTalk, which is a quarterly newsletter published by the Colorado Geological Survey dealing with all aspects of geology throughout the state of Colorado. Links are provided for more resources.

259

Relative Importance of Deterministic and Stochastic Processes in Driving Arbuscular Mycorrhizal Fungal Assemblage during the Spreading of a Toxic Plant  

PubMed Central

Both deterministic and stochastic processes are expected to drive the assemblages of arbuscular mycorrhizal (AM) fungi, but little is known about the relative importance of these processes during the spreading of toxic plants. Here, the species composition and phylogenetic structure of AM fungal communities colonizing the roots of a toxic plant, Ligularia virgaurea, and its neighborhood plants, were analyzed in patches with different individual densities of L. virgaurea (represents the spreading degree). Community compositions of AM fungi in both root systems were changed significantly by the L. virgaurea spreading, and also these communities fitted the neutral model very well. AM fungal communities in patches with absence and presence of L. virgaurea were phylogenetically random and clustered, respectively, suggesting that the principal ecological process determining AM fungal assemblage shifted from stochastic process to environmental filtering when this toxic plant was present. Our results indicate that deterministic and stochastic processes together determine the assemblage of AM fungi, but the dominant process would be changed by the spreading of toxic plants, and suggest that the spreading of toxic plants in alpine meadow ecosystems might be involving the mycorrhizal symbionts. PMID:24748393

Mao, Lin; Jiang, Shengjing; Zhang, Qi; Cheng, Gang; An, Lizhe; Du, Guozhen; Feng, Huyuan

2014-01-01

260

Geologic Resource Evaluation of Pu'ukohola Heiau National Historic Site, Hawai'i: Part I, Geology and Coastal Landforms  

USGS Publications Warehouse

Geologic resource inventories of lands managed by the National Park Service (NPS) are important products for the parks and are designed to provide scientific information to better manage park resources. Park-specific geologic reports are used to identify geologic features and processes that are relevant to park ecosystems, evaluate the impact of human activities on geologic features and processes, identify geologic research and monitoring needs, and enhance opportunities for education and interpretation. These geologic reports are planned to provide a brief geologic history of the park and address specific geologic issues forming a link between the park geology and the resource manager. The Kona coast National Parks of the Island of Hawai'i are intended to preserve the natural beauty of the Kona coast and protect significant ancient structures and artifacts of the native Hawaiians. Pu'ukohola Heiau National Historic Site (PUHE), Kaloko-Honokohau National Historical Park (KAHO), and Pu'uhonua O Honaunau National Historical Park (PUHO) are three Kona parks studied by the U.S. Geological Survey (USGS) Coastal and Marine Geology Team in cooperation with the National Park Service. This report is one of six related reports designed to provide geologic and benthic-habitat information for the three Kona parks. Each geology and coastal-landform report describes the regional geologic setting of the Hawaiian Islands, gives a general description of the geology of the Kona coast, and presents the geologic setting and issues for one of the parks. The related benthic-habitat mapping reports discuss the marine data and habitat classification scheme, and present results of the mapping program. Pu'ukohola Heiau National Historic Site (PUHE) is the smallest (~86 acres) of three National Parks located on the leeward Kona coast of the Island of Hawai'i. The main structure at PUHE, Pu'ukohola Heiau, is an important historical temple that was built during 1790-91 by King Kamehameha I (also known as Kamehameha the Great) and is often associated with the founding of the Hawaiian Kingdom (Greene, 1993). The temple was constructed to incur the favor of the king's personal war god Kuka'ilimoku during the time that Kamehameha I waged several battles in an attempt to extend his control over all the Hawaiian Islands. The park is also the site of the older Mailekini Heiau, which was used by the ancestors of Kamehameha I, and an offshore, submerged temple, Hale O Kapuni Heiau, that was dedicated to the shark god. The park occupies the scenic Hill of the Whale overlooking Kawaihae Bay and Pelekane Beach. The seaward-sloping lands of PUHE lie at the convergence of lava flows formed by both Mauna Kea and Kohala Volcanoes. The park coastline is mostly rocky, with the exception of a small beach developed at the north boundary where an intermittent stream enters the sea. The park is bounded to the north by Kawaihae Harbor, to the south by Samuel M. Spencer Beach Park, and to the west by a broad submerged reef. The adjacent reef area is discussed in detail in the accompanying report by Cochran and others (2006). They mapped from the shoreline to depths of approximately 40 m, where the shelf drops off to a sand-covered bottom. PUHE park boundaries extend only to the mean high-tide line, however, landscape impacts created by development around the park are of concern to Park management.

Richmond, Bruce M.; Cochran, Susan A.; Gibbs, Ann E.

2008-01-01

261

Quality assurance plan for the collection and processing of sediment data by the U.S. Geological Survey, Water Resources Division  

USGS Publications Warehouse

The U.S. Geological Survey sediment data quality assurance plan identifies and explains required quality assurance and suggested quality control practices. The approach is to subdivide the process for obtaining sediment data into 3 parts: (1) field, (2) office, and (3) laboratory operations. The report also summarizes recommended goals for each subcategory. The quality assurance and quality control practices are described by stating the minimum acceptable activities that a district should conduct. For example, the plan describes field calibration of thermometers and standards used to calibrate a thermometer. The plan also proposes corrective actions if the quality control procedures identify a problem. The plan describes the formal reports prepared by a district that describe the completeness of sediment data and presents an evaluation of data obtained by the quality assurance program. Also described in the plan are the external (non-district) reviews that are needed to examine district sediment operations for conformity with district quality assurance plans and national quality assurance programs.

Knott, J.M.; Glysson, G.D.; Malo, B.A.; Schroeder, L.J.

1993-01-01

262

Importance of lateral transport processes to 210Pb budget in the eastern Chukchi Sea during summer 2003  

NASA Astrophysics Data System (ADS)

Activity concentrations of dissolved and particulate 210Pb and 226Ra in the water column were measured in the eastern Chukchi Sea during summer 2003. 234Th/238U disequilibria were used to estimate the scavenging fluxes of 210Pb from the water column to the underlying sediments. Our results showed that concentrations of 210Pb and its distributions were mainly influenced by mixing processes of water masses and sediment resuspension. The residence times of 210Pb in the eastern Chukchi Sea ranged from 5 to 103 d. Short residence times were mostly observed at the shelf stations, indicating a more effective particle scavenging in the shelf region. A mass balance model was constructed to evaluate the contribution of lateral transport to 210Pb budget in the water column. The lateral transport fluxes of 210Pb ranged from 17 to 177 Bq/m2/a, comprising up to 63-94% of the total supply of 210Pb in the eastern Chukchi Sea. We hypothesize that the accumulative removal of 210Pb in the Pacific inflow waters during their transport across the Chukchi Sea and the import of 210Pb from sea ice rafted sediments are the two major lateral transport pathways for the import of 210Pb to the eastern Chukchi Sea. Our results highlight the importance of lateral transport processes to the geographical distribution of particle-reactive elements and their biogeochemical cycles in the Arctic Ocean.

Chen, Min; Ma, Qiang; Guo, Laodong; Qiu, Yusheng; Li, Yanping; Yang, Weifeng

2012-12-01

263

Maryland Geological Survey  

NSDL National Science Digital Library

The Maryland Geological Survey (MGS) homepage contains information from MGS programs on hydrogeology, hydrology, coastal and estuarine geology, environmental geology and mineral resources; an online guide to Maryland geology; and information on oyster habitat restoration projects. There are also maps, data, information on MGS publications, MGS news, and online educational resources.

264

Arsenic in New Jersey Coastal Plain streams, sediments, and shallow groundwater: effects from different geologic sources and anthropogenic inputs on biogeochemical and physical mobilization processes  

USGS Publications Warehouse

Arsenic (As) concentrations in New Jersey Coastal Plain streams generally exceed the State Surface Water Quality Standard (0.017 micrograms per liter (µg/L)), but concentrations seldom exceed 1 µg/L in filtered stream-water samples, regardless of geologic contributions or anthropogenic inputs. Nevertheless, As concentrations in unfiltered stream water indicate substantial variation because of particle inputs from soils and sediments with differing As contents, and because of discharges from groundwater of widely varying chemistry. In the Inner Coastal Plain, streams draining to lower reaches of the Delaware River traverse As-rich glauconitic sediments of marine origin in which As contents typically are about 20 milligrams per kilogram (mg/kg) or greater. In some of these sedimentary units, As concentrations exceed the New Jersey drinking-water maximum contaminant level (5 µg/L) in shallow groundwater that discharges to streams. Microbes, fueled by organic carbon beneath the streambed, reduce iron (Fe) and As, releasing As and Fe into solution in the shallow groundwater from geologic materials that likely include (in addition to glauconite) other phyllosilicates, apatite, and siderite. When the groundwater discharges to the stream, the dissolved Fe and As are oxidized, the Fe precipitates as a hydroxide, and the As sorbs or co-precipitates with the Fe. Because of the oxidation/precipitation process, dissolved As concentrations measured in filtered stream waters of the Inner Coastal Plain are about 1 µg/L, but the total As concentrations (and loads) are greater, substantially amplified by As-bearing suspended sediment in stormflows. In the Outer Coastal Plain, streams draining to the Atlantic Ocean traverse quartz-rich sediments of mainly deltaic origin where the As content generally is low ( With a history of agriculture in the New Jersey Coastal Plain, anthropogenic inputs of As, such as residues from former pesticide applications in soils, can amplify any geogenic As in runoff. Such inputs contribute to an increased total As load to a stream at high stages of flow. As a result of yet another anthropogenic influence, microbes that reduce and mobilize As beneath the streambeds are stimulated by inputs of dissolved organic carbon (DOC). Although DOC is naturally occurring, anthropogenic contributions from wastewater inputs may deliver increased levels of DOC to subsurface soils and ultimately groundwater. Arsenic concentrations may increase with the increases in pH of groundwater and stream water in developed areas receiving wastewater inputs, as As mobilization caused by pH-controlled sorption and desorption reactions are likely to occur in waters of neutral or alkaline pH (for example, Nimick and others, 1998; Barringer and others, 2007b). Because of the difference in As content of the geologic materials in the two sub-provinces of the Coastal Plain, the amount of As that is mobile in groundwater and stream water is, potentially, substantially greater in the Inner Coastal Plain than in the Outer Coastal Plain. In turn, streams within the Inner and Outer Coastal Plain can receive substantially more As in groundwater discharge from developed areas than from environments where DOC appears to be of natural origin.

Barringer, Julia L.; Reilly, Pamela A.; Eberl, Dennis D.; Mumford, Adam C.; Benzel, William M.; Szabo, Zoltan; Shourds, Jennifer L.; Young, Lily Y.

2013-01-01

265

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

266

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.

267

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  

E-print Network

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...

Brand, John Richard

2006-04-12

268

Objective Subsurface Geological Modeling using Geological Columns - A case study for the Kisarazu Distinct, Japan  

NASA Astrophysics Data System (ADS)

Geological models of subsurface structure play an important role in disaster assessment, environmental preservation, and underground utilization. These models are often constructed subjectively based on geological data obtained from field survey. However, reliability of subjective model depends on modeler's knowledge and experience as well as on quality of basic data. In order to ensure a more stable reliability of the model, objective approach is necessary. The purpose of this study is to establish an objective geological modeling method. For the purpose of this study, we constructed a subsurface geological model focusing on mathematical treatment of stratigraphy. Study area is the Kisarazu distinct, in the middle part of Chiba Prefecture, Japan. Basic data for modeling are 44 geological columns. In the modeling, firstly, we constructed a Logical Model of Geological Structure (LMGS) that defines a positional relation between geological boundary surfaces and geological units. The LMGS is objectively given by recurrence formula derived from a sequence of geological events arranged in chronological order. Secondly, we generated Digital Elevation Models (DEMs) of geological boundary surfaces using geological columns. Thirdly, we constructed an objective geological model using the LMGS and the DEMs. Finally, we visualized the model in 2D and 3D using GRASS GIS. As a result, in the areas with high number of geological columns, geological map and geological cross-sections derived from objective model were in good agreement with the ones derived from subjective model reported in other studies. In the areas with low number of geological columns, the objective map and cross-sections were somewhat different from subjective ones. In conclusion, the results indicate that objective model may give new findings about subsurface structure. In addition, the objective model gives a more stable reliability than the subjective model because the former ensures traceability of modeling procedures. The LMGS is unfit for complicated geological structures like lens. For the solution of this problem, we need to improve theoretical base of the LMGS.

Nonogaki, S.; Nakazawa, T.

2013-12-01

269

Femtosecond spectroscopy of bacterial photosynthesis{emdash}towards an understanding of the most important energy conversion process on earth  

SciTech Connect

Reaction centers of bacterial photosynthesis are ideal systems to study photosynthetic energy conversion. Femtosecond spectroscopy has delivered extensive information on the molecular mechanisms of the primary electron transfer. The data show, that primary electron transfer is an ultrafast stepwise reaction, where the electron is transferred via closely spaced pigments with reaction times as fast as 0.9 ps and 3.5 ps. Experiments on mutated and modified reaction centers allow to determine the energetics of the various intermediates in the reaction center. Recently, femtosecond experiments with light pulses in the mid infrared have shown, that an additional fast process occurs on the 200 fs timescale in the initially excited special pair. Only afterwards the well established electron transfer reactions take place. This fast process may be of importance for the optimization of the primary reaction. {copyright} {ital 1996 American Institute of Physics.}

Zinth, W.; Hamm, P.; Arlt, T.; Wachtveitl, J. [Ludwig Maximilians Universitaet Muenchen, Institut fuer Medizinische Optik, Barbarastr.1 6, 80797 Muenchen (Germany)

1996-04-01

270

Importance of the Voronoi domain partition for position-jump reaction-diffusion processes on nonuniform rectilinear lattices.  

PubMed

Position-jump processes are used for the mathematical modeling of spatially extended chemical and biological systems with increasing frequency. A large subset of the literature concerning such processes is concerned with modeling the effect of stochasticity on reaction-diffusion systems. Traditionally, computational domains have been divided into regular voxels. Molecules are assumed well mixed within each of these voxels and are allowed to react with other molecules within the same voxel or to jump to neighboring voxels with predefined transition rates. For a variety of reasons implementing position-jump processes on irregular grids is becoming increasingly important. However, it is not immediately clear what form an appropriate irregular partition of the domain should take if it is to allow the derivation of mean molecular concentrations that agree with a given partial differential equation for molecular concentrations. It has been demonstrated, in one dimension, that the Voronoi domain partition is the appropriate method with which to divide the computational domain. In this Brief Report, we investigate theoretically the propriety of the Voronoi domain partition as an appropriate method to partition domains for position-jump models in higher dimensions. We also provide simulations of diffusion processes in two dimensions in order to corroborate our results. PMID:24329390

Yates, Christian A; Baker, Ruth E

2013-11-01

271

Importance of the Voronoi domain partition for position-jump reaction-diffusion processes on nonuniform rectilinear lattices  

NASA Astrophysics Data System (ADS)

Position-jump processes are used for the mathematical modeling of spatially extended chemical and biological systems with increasing frequency. A large subset of the literature concerning such processes is concerned with modeling the effect of stochasticity on reaction-diffusion systems. Traditionally, computational domains have been divided into regular voxels. Molecules are assumed well mixed within each of these voxels and are allowed to react with other molecules within the same voxel or to jump to neighboring voxels with predefined transition rates. For a variety of reasons implementing position-jump processes on irregular grids is becoming increasingly important. However, it is not immediately clear what form an appropriate irregular partition of the domain should take if it is to allow the derivation of mean molecular concentrations that agree with a given partial differential equation for molecular concentrations. It has been demonstrated, in one dimension, that the Voronoi domain partition is the appropriate method with which to divide the computational domain. In this Brief Report, we investigate theoretically the propriety of the Voronoi domain partition as an appropriate method to partition domains for position-jump models in higher dimensions. We also provide simulations of diffusion processes in two dimensions in order to corroborate our results.

Yates, Christian A.; Baker, Ruth E.

2013-11-01

272

Prediction of oil-bearing single sandbody by 3D geological modeling combined with seismic inversion  

Microsoft Academic Search

The prediction of geometry and distribution for oil-bearing single sandbody is an important task in fine reservoir characterization. According to the geologic feature, quality of seismic data, and the study purposes of G Oilfield in Bohai Bay Basin, seismic inversion of shale volume was processed using sparse spike method. The processing result of seismic inversion was integrated into the 3D

Wu Jian; Li Fanhua

2009-01-01

273

Overview of the Water, Energy, Biogeochemical Budgets Program of the U.S. Geological Survey  

Microsoft Academic Search

Small watershed studies serve as an important mechanism to understand changes in a broad range of hydrologic environments at a scale where multiple processes can be understood. The U. S. Geological Survey's (USGS) Water, Energy, and Biogeochemical Budgets (WEBB) program was designed to understand processes in small watersheds located in geographically diverse environments that represent a range of hydrologic, ecologic,

Mary Jo Baedecker

274

Geologic Mapping of Mars  

NASA Astrophysics Data System (ADS)

Planetary geologic mapping involves integrating a terrestrial-based understanding of surface and subsurface processes and mapping principles to investigate scientific questions. Mars mappers must keep in mind that physical processes, such as wind and flowing water on Mars, are or were different from terrestrial processes because the planetary atmospheres have changed differently over time. Geologic mapping of Mars has traditionally been done by hand using overlays on photomosaics of Viking Orbiter and Mariner images. Photoclinometry and shadow measurements have been used to determine elevations, and the distribution and size of craters have been used to determine the relative ages of surfaces- more densely cratered surfaces are older. Some mappers are now using computer software (ranging from Photoshop to ArcInfo) to facilitate mapping, though their applications must be carefully executed so that registration of the images remains true. Images and some mapping results are now available on the internet, and new data from recent missions to Mars (Pathfinder and Surveyor) will offer clarifying information to mapping efforts. This paper consists chiefly of pictures and diagrams.

Price, Katherine H.

1998-05-01

275

Efficient Geological Modelling of Large AEM Surveys  

NASA Astrophysics Data System (ADS)

Combining geological expert knowledge with geophysical observations into a final 3D geological model is, in most cases, not a straight forward process. It typically involves many types of data and requires both an understanding of the data and the geological target. When dealing with very large areas, such as modelling of large AEM surveys, the manual task for the geologist to correctly evaluate and properly utilise all the data available in the survey area, becomes overwhelming. In the ERGO project (Efficient High-Resolution Geological Modelling) we address these issues and propose a new modelling methodology enabling fast and consistent modelling of very large areas. The vision of the project is to build a user friendly expert system that enables the combination of very large amounts of geological and geophysical data with geological expert knowledge. This is done in an "auto-pilot" type functionality, named Smart Interpretation, designed to aid the geologist in the interpretation process. The core of the expert system is a statistical model that describes the relation between data and geological interpretation made by a geological expert. This facilitates fast and consistent modelling of very large areas. It will enable the construction of models with high resolution as the system will "learn" the geology of an area directly from interpretations made by a geological expert, and instantly apply it to all hard data in the survey area, ensuring the utilisation of all the data available in the geological model. Another feature is that the statistical model the system creates for one area can be used in another area with similar data and geology. This feature can be useful as an aid to an untrained geologist to build a geological model, guided by the experienced geologist way of interpretation, as quantified by the expert system in the core statistical model. In this project presentation we provide some examples of the problems we are aiming to address in the project, and show some preliminary results.

Bach, Torben; Martlev Pallesen, Tom; Jørgensen, Flemming; Lundh Gulbrandsen, Mats; Mejer Hansen, Thomas

2014-05-01

276

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; processing, taxonomy, and quality control of benthic macroinvertebrate samples  

USGS Publications Warehouse

Qualitative and quantitative methods to process benthic macroinvertebrate (BMI) samples have been developed and tested by the U.S. Geological Survey?s National Water Quality Laboratory Biological Group. The qualitative processing method is based on visually sorting a sample for up to 2 hours. Sorting focuses on attaining organisms that are likely to result in taxonomic identifications to lower taxonomic levels (for example, Genus or Species). Immature and damaged organisms are also sorted when they are likely to result in unique determinations. The sorted sample remnant is scanned briefly by a second person to determine if obvious taxa were missed. The quantitative processing method is based on a fixed-count approach that targets some minimum count, such as 100 or 300 organisms. Organisms are sorted from randomly selected 5.1- by 5.1-centimeter parts of a gridded subsampling frame. The sorted remnant from each sample is resorted by a second individual for at least 10 percent of the original sort time. A large-rare organism search is performed on the unsorted remnant to sort BMI taxa that were not likely represented in the sorted grids. After either qualitatively or quantitatively sorting the sample, BMIs are identified by using one of three different types of taxonomic assessment. The Standard Taxonomic Assessment is comparable to the U.S. Environmental Protection Agency Rapid Bioassessment Protocol III and typically provides Genus- or Species-level taxonomic resolution. The Rapid Taxonomic Assessment is comparable to the U.S. Environmental Protection Agency Rapid Bioassessment Protocol II and provides Familylevel and higher taxonomic resolution. The Custom Taxonomic Assessment provides Species-level resolution whenever possible for groups identified to higher taxonomic levels by using the Standard Taxonomic Assessment. The consistent use of standardized designations and notes facilitates the interpretation of BMI data within and among water-quality studies. Taxonomic identifications are quality assured by verifying all referenced taxa and randomly reviewing 10 percent of the taxonomic identifications performed weekly by Biological Group taxonomists. Taxonomic errors discovered during this review are corrected. BMI data are reviewed for accuracy and completeness prior to release. BMI data are released phylogenetically in spreadsheet format and unprocessed abundances are corrected for laboratory and field subsampling when necessary.

Moulton, Stephen R., II; Carter, James L.; Grotheer, Scott A.; Cuffney, Thomas F.; Short, Terry M.

2000-01-01

277

Glossary of Geologic Terms  

NSDL National Science Digital Library

This page from Iowa State University presents a general glossary of geologic terms. The site would be a good reference for geology coursework. This glossary of geologic terms is based on the glossary in Earth: An Introduction to Geologic Change, by S. Judson and S.M. Richardson (Englewood Cliffs, NJ, Prentice Hall, 1995). Where possible, definitions conform generally, and in some cases specifically, to definitions given in Robert L Bates and Julia A Jackson (editors), Glossary of Geology, 3rd ed., American Geological Institute, Alexandria, Virginia, 1987.

2011-07-18

278

Venus geology  

NASA Technical Reports Server (NTRS)

The Magellan mission to Venus is reviewed. The scientific investigations conducted by 243-day cycles encompass mapping with a constant incidence angle for the radar, observing surface changes from one cycle to the next, and targeting young-looking volcanos. The topography of Venus is defined by the upper boundary of the crust and upwelling from lower domains. Tectonic features such as rift zones, linear mountain belts, ridge belts, and tesserae are described. The zones of tesserae are unique to the planet. Volcanism accounts for about 80 percent of the observed surface, the remainder being volcanic deposits which have been reworked by tectonism or impacts. Magellan data reveal about 900 impact craters with flow-like ejecta resulting from the fall of meteoroids. It is concluded that the age of the Venusian surface varies between 0 and 800 million years. Tectonic and volcanic activities dominate the formation of the Venus topography; such processes as weathering and erosion are relatively unimportant on Venus.

Mclaughlin, W. I.

1991-01-01

279

GEOLOGY, January 2008 35 INTRODUCTION  

E-print Network

GEOLOGY, January 2008 35 INTRODUCTION An important component of soil formation is the chemical a variety of methods in noneroding landscapes where the soil age is the time elapsed since the stabilization weathering of primary minerals. In quantifying mineral chemical weathering rates, one approach has been

280

Horse Evolution Geology 331Geology 331  

E-print Network

Horse Evolution Geology 331Geology 331 Paleontology #12;Horses #12;Equus caballus #12;#12;Equus;EquusMerychippusMiohippusHyracotherium Hind feet left, front feet right. #12;Hyracotherium or Eohippus;MerychippusMerychippus from the MioceneMiocene, a plains grazer #12;The modern horseThe modern horse Equus

Kammer, Thomas

281

Geological assessing of urban environments with a systematic mapping survey: The 1:5000 urban geological map of Catalonia  

NASA Astrophysics Data System (ADS)

The ground features of urban areas and the geologic processes that operate on them are, in general, strongly altered from their natural original condition as a result of anthropogenic activities. Assessing the stability of the ground, the flooding areas, and, the health risk as a consequence of soil pollution, are, among others, fundamental topics of urban areas that require a better understanding. The development of systematic urban geological mapping projects provides valuable resources to address these issues. Since 2007, the Institut Geologic de Catalunya (IGC) runs an urban geological mapping project, to provide accurate geologic information of county capitals and towns of more than 10000 inhabitants of Catalonia. The urban zones of 131 towns will be surveyed for this project, totalizing an area of about 2200 km2 to be mapped in 15 years. According to the 2008 census, the 82 % of the population of Catalonia (7.242.458 inhabitants) lives in the areas to be mapped in this project. The mapping project integrates in a GIS environment the following subjects: - Data from pre-existing geotechnical reports, historical geological and topographical maps and, from historical aerial photographs. - Data from available borehole databases. - Geological characterization of outcrops inside the urban network and neighbouring areas. - Geological, chemical and physical characterisation of representative rocks, sediments and soils. - Ortophotographs (0.5 m pixel size) and digital elevation models (5 meter grid size) made from historical aerial photographs, to depict land use changes, artificial deposits and geomorphological elements that are either hidden or destroyed by urban sprawl. - Detailed geological mapping of quaternary sediments, subsurface bedrock and artificial deposits. - Data from subsurface prospection in areas with insufficient or confuse data. - 3D modelling of the main geological surfaces such as the top of the pre-quaternary basement. All the gathered data is harmonised and stored it in a database. The analysis of the database allows to compile and print the 1:5000 scale urban geological map according to the 1:5000 topographic grid of Catalonia. The map is composed by a principal map, geologic cross sections and several complementary maps, charts and tables. Regardless of the geological map units, the principal map also includes the main artificial deposits (such as infilled river valleys and road embankments), very recent or current superficial deposits, contours of outcropping areas, structural data and other relevant information gathered in stations, sampling points, boreholes indicating the thickness of artificial deposits and the depth of the pre-quaternary basement, contour lines of the top of the pre-quaternary basement surface and, water level data. The complementary maps and charts may change depending on the gathered data, the geological features of the area and the urban typology. However, the most representative complementary maps that includes the printed urban map are the quaternary subsurface bedrock map and the isopach map of thickness of quaternary and anthropogenic deposits. The map also includes charts and tables of relevant physical and chemical parameters of the geological materials, harmonised downhole lithological columns from selected boreholes, and, photographs and figures illustrating the geology of the mapped area and how urbanisation has changed the natural environment. The object of this systematic urban mapping survey is to provide a robust database to be used in targeted studies related to urban planning, geoengineering works, soil pollution and other important environmental issues that society should deal in the future.

Vilà, Miquel; Pi, Roser; Cirés, Jordi; de Paz, Ana; Berástegui, Xavier

2010-05-01

282

Geology Major www.geology.pitt.edu/undergraduate/geology.html  

E-print Network

, including the quality of air, water, and soil. Geology majors have hiked the Appalachian Trail, gone of GEOL at the 1000 level or above. Chemistry requirements CHEM 0110 General Chemistry 1 CHEM 0120 General

Jiang, Huiqiang

283

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

284

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

285

Geology in the Junior School.  

ERIC Educational Resources Information Center

Suggested is that geology can contribute significantly to the general education of our students from the point of view of relevance and increasing understanding of the planet we inhabit which should be learned as a series of interacting processes involving a time dimension. Several curriculum projects are outlined. (Author/DS)

McIntyre, Norm

1979-01-01

286

Weird Geology: The Devil's Tower  

NSDL National Science Digital Library

This page features a brief introduction to the several theories about the geological processes that formed Devil's Tower, which rises 1,267 feet above the nearby Belle Fourche River and is still considered a sacred place by some Native American Tribes. Information on climbing the tower as well as images and a cross section are provided.

Krystek, Lee; Mystery, The M.

287

Geology of Kilauea volcano  

SciTech Connect

This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower east rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably has several separate hydrothermal-convection systems that develop in response to the dynamic behavior of the volcano and the influx of abundant meteoric water. Important features of some of these hydrothermal-convection systems are known through studies of surface geology and drill holes. Observations of eruptions during the past two centuries, detailed geologic mapping, radiocarbon dating, and paleomagnetic secular-variation studies indicate that Kilauea has erupted frequently from its summit and two radial rift zones during Quaternary time. Petrologic studies have established that Kilauea erupts only tholeiitic basalt. Extensive ash deposits at Kilauea's summit and on its LERZ record locally violent, but temporary, disruptions of local hydrothermal-convection systems during the interaction of water or steam with magma. Recent drill holes on the LERZ provide data on the temperatures of the hydrothermal-convection systems, intensity of dike intrusion, porosity and permeability, and an increasing amount of hydrothermal alteration with depth. The prehistoric and historic record of volcanic and seismic activity indicates that magma will continue to be supplied to deep and shallow reservoirs beneath Kilauea's summit and rift zones and that the volcano will be affected by eruptions and earthquakes for many thousands of years. 71 refs., 2 figs.

Moore, R.B. (Geological Survey, Denver, CO (United States). Federal Center); Trusdell, F.A. (Geological Survey, Hawaii National Park, HI (United States). Hawaiian Volcano Observatory)

1993-08-01

288

Geology on a Sand Budget  

NSDL National Science Digital Library

Earth science teaches know how frustrating it can be to spend hundreds of dollars on three-dimensional (3-D) models of Earth's geologic features, only to use the models for a few class periods. To avoid emptying an already limited science budget, teachers can use a simple alternative to the expensive 3-D models--sand. Modeling geologic processes and features with sand is an effective way for teachers to promote student understanding of Earth science topics, quickly assess students' prior knowledge, and identify common misconceptions.

Kane, Jacqueline

2004-09-01

289

REMOTE SENSING GEOLOGICAL SURVEY  

E-print Network

/Enhanced Thematic Mapper) Imagery Collection Examples of sensors used in CPRM geologic projects Geological Survey for ground water in crystalline terrain 3(VIS)4(NIR)5(SWIR) Moji and Pardo Rivers Basin ­ São Paulo State 3 and Reflection Radiometer) Imagery Collection in CPRM Examples of sensors used in the CPRM geologic projects #12

290

Glossary of Geology  

Microsoft Academic Search

The Glossary has expanded coverage particularly in such active fields as carbonate sedimentology, environmental geology and geophysics, GIS, GPS, hydrology and hydraulics, marine and coastal geology, organic geochemistry, paleoecology, seismology, stratigraphic nomenclature, speleology and karst, and structural geology and tectonics. Many definitions provide a syllabification guide and background information. Thus a reader will learn the difference between look-alike pairs, such

Julia A. Jackson

2005-01-01

291

Development of engineering geologic performance standards for land-use regulation in Sabine Pass, Texas  

E-print Network

and plants, subsurface geology, geologic history, hydrogeology, and geologic processes affect- ing the area. Geomorphology At the regional scale the chenier-marsh system occurring in Sabine Pass, Texas is part of the larger deltaic-interdeltaic system... and plants, subsurface geology, geologic history, hydrogeology, and geologic processes affect- ing the area. Geomorphology At the regional scale the chenier-marsh system occurring in Sabine Pass, Texas is part of the larger deltaic-interdeltaic system...

Vaught, Richmond Murphy

2012-06-07

292

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.

293

The Importance of Simulating Changes in Topography in Process-based Soil Erosion Modelling: Implications for Landscape Evolution Modelling  

NASA Astrophysics Data System (ADS)

A model has been developed to begin to fill the gap between existing soil-erosion and landscape-evolution models. Most soil-erosion models are high resolution, run on short time scales and are based on realistic process dynamics but do not update topography. In contrast landscape-evolution models are typically run on large areas over long periods but use highly simplified process models. In the current study an existing process-based soil-erosion model has been adapted that has been adapted to allow prediction of changes in topography in order to begin to bring these two types of model together. The model, MAHLERAN (Model for Assessing Hillslope-Landscape Erosion, Runoff And Nutrients) employs a conceptualization of soil-erosion processes which takes account of the fact that interrill flow on hillslopes is dominated by rolling or sliding along surfaces or in short steps akin to movement of bedload. Parameterizations of the different soil detachment and transport mechanisms that occur under rainfall are used to better capture the reality of soil-erosion processes. Overland flow is modelled using a kinematic wave approximation to the 2D shallow water equations combined with the Darcy-Weisbach flow equation to calculate velocity. Flow is assumed to be in direction of steepest descent in cardinal directions on a simple finite difference grid. The model includes an infiltration component based on the Smith and Parlange approach. Sediment is divided into six size classes in order to account for differing behaviour of particles of different size and is transported by splash, flow (concentrated/unconcentrated) or in suspension. Detachment is assumed to occur in one of three ways: (1) as a function of raindrop detachment alone when there no overland flow; (2) raindrop detachment modified to account for surface layer effects in the case of unconcentrated overland flow; and (3) concentrated erosion when flow is turbulent. Deposition is modelled using a transport-distance approach described by an exponential distribution function. The initial, static version of the model has been modified so that surface topography during a storm event may be updated at regular intervals or at every time step. The dynamic version of the model makes it possible to test how important topographic change is in controlling runoff and erosion processes in events of different magnitudes or over a series of consecutive events. Results from field data under natural conditions in Japan and USA and experimental data from plot-scale rainfall simulation experiments at the University of Tsukuba Large Rainfall-Simulation Facility have been used to evaluate the model. Furthermore, sensitivity analysis is carried out to assess the impacts of dynamic changes in topography on flow and particle transport more generally. The introduction of topographic change during storms provides a more realistic model of what happens in heavy storm conditions especially on steep slopes and could be used to inform the development of improved landscape-evolution models over longer simulation periods.

Hewett, Caspar J. M.; Wainwright, John; Parsons, Anthony J.; Cooper, James R.; Kitchener, Ben; Hargrave, Graham K.; Long, Edward J.; Onda, Yuichi; Patin, Jeremy

2014-05-01

294

Altered zinc transport disrupts mitochondrial protein processing/import in fragile X-associated tremor/ataxia syndrome  

PubMed Central

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that affects individuals who are carriers of small CGG premutation expansions in the fragile X mental retardation 1 (FMR1) gene. Mitochondrial dysfunction was observed as an incipient pathological process occurring in individuals who do not display overt features of FXTAS ( 1). Fibroblasts from premutation carriers had lower oxidative phosphorylation capacity (35% of controls) and Complex IV activity (45%), and higher precursor-to-mature ratios (P:M) of nDNA-encoded mitochondrial proteins (3.1-fold). However, fibroblasts from carriers with FXTAS symptoms presented higher FMR1 mRNA expression (3-fold) and lower Complex V (38%) and aconitase activities (43%). Higher P:M of ATPase ?-subunit (ATPB) and frataxin were also observed in cortex from patients that died with FXTAS symptoms. Biochemical findings observed in FXTAS cells (lower mature frataxin, lower Complex IV and aconitase activities) along with common phenotypic traits shared by Friedreich's ataxia and FXTAS carriers (e.g. gait ataxia, loss of coordination) are consistent with a defective iron homeostasis in both diseases. Higher P:M, and lower ZnT6 and mature frataxin protein expression suggested defective zinc and iron metabolism arising from altered ZnT protein expression, which in turn impairs the activity of mitochondrial Zn-dependent proteases, critical for the import and processing of cytosolic precursors, such as frataxin. In support of this hypothesis, Zn-treated fibroblasts showed a significant recovery of ATPB P:M, ATPase activity and doubling time, whereas Zn and desferrioxamine extended these recoveries and rescued Complex IV activity. PMID:21558427

Napoli, Eleonora; Ross-Inta, Catherine; Wong, Sarah; Omanska-Klusek, Alicja; Barrow, Cedrick; Iwahashi, Christine; Garcia-Arocena, Dolores; Sakaguchi, Danielle; Berry-Kravis, Elizabeth; Hagerman, Randi; Hagerman, Paul J.; Giulivi, Cecilia

2011-01-01

295

Kansas Geological Survey  

NSDL National Science Digital Library

The mission of the Kansas Geological Survey, operated by the University of Kansas in connection with its research and service program, is to conduct geological studies and research and to collect, correlate, preserve, and disseminate information leading to a better understanding of the geology of Kansas, with special emphasis on natural resources of economic value, water quality and quantity, and geologic hazards. The website includes information about the High Plains and Ogallala aquifers, the Upper Arkansas corridor, the Dakota aquifer, county and state geologic maps, an online bibliography of Kansas geology, publications, a photo archive, a digital petroleum atlas, a petroleum primer for the state, gravity and magnetic maps, Hugoton project information, and details about the Hutchinson Kansas natural gas fires. The educational resources section contains a mineral information page for the state, and GeoKansas, which provides information on state geology for schools.

296

Phylogeographic patterns of genetic diversity in eastern Mediterranean water frogs have been determined by geological processes and climate change in the Late Cenozoic.  

PubMed

AIM: Our aims were to assess the phylogeographic patterns of genetic diversity in eastern Mediterranean water frogs and to estimate divergence times using different geological scenarios. We related divergence times to past geological events and discuss the relevance of our data for the systematics of eastern Mediterranean water frogs. LOCATION: The eastern Mediterranean region. METHODS: Genetic diversity and divergence were calculated using sequences of two protein-coding mitochondrial (mt) genes: ND2 (1038 bp, 119 sequences) and ND3 (340 bp, 612 sequences). Divergence times were estimated in a Bayesian framework under four geological scenarios representing alternative possible geological histories for the eastern Mediterranean. We then compared the different scenarios using Bayes factors and additional geological data. RESULTS: Extensive genetic diversity in mtDNA divides eastern Mediterranean water frogs into six main haplogroups (MHG). Three MHGs were identified on the Anatolian mainland; the most widespread MHG with the highest diversity is distributed from western Anatolia to the northern shore of the Caspian Sea, including the type locality of Pelophylax ridibundus. The other two Anatolian MHGs are restricted to south-eastern Turkey, occupying localities west and east of the Amanos mountain range. One of the remaining three MHGs is restricted to Cyprus; a second to the Levant; the third was found in the distribution area of European lake frogs (P. ridibundus group), including the Balkans. MAIN CONCLUSIONS: Based on geological evidence and estimates of genetic divergence we hypothesize that the water frogs of Cyprus have been isolated from the Anatolian mainland populations since the end of the Messinian salinity crisis (MSC), i.e. since c. 5.5-5.3 Ma, while our divergence time estimates indicate that the isolation of Crete from the mainland populations (Peloponnese, Anatolia) most likely pre-dates the MSC. The observed rates of divergence imply a time window of c. 1.6-1.1 million years for diversification of the largest Anatolian MHG; divergence between the two other Anatolian MHGs may have begun about 3.0 Ma, apparently as a result of uplift of the Amanos Mountains. Our mtDNA data suggest that the Anatolian water frogs and frogs from Cyprus represent several undescribed species. PMID:22473251

Ak?n, Ci?dem; Bilgin, C Can; Beerli, Peter; Westaway, Rob; Ohst, Torsten; Litvinchuk, Spartak N; Uzzell, Thomas; Bilgin, Metin; Hotz, Hansjürg; Guex, Gaston-Denis; Plötner, Jörg

2010-11-01

297

Streamflow and water-quality conditions including geologic sources and processes affecting selenium loading in the Toll Gate Creek watershed, Aurora, Arapahoe County, Colorado, 2007  

USGS Publications Warehouse

Toll Gate Creek is a perennial stream draining a suburban area in Aurora, Colorado, where selenium concentrations have consistently exceeded the State of Colorado aquatic-life standard for selenium of 4.6 micrograms per liter since the early 2000s. In cooperation with the City of Aurora, Colorado, Utilities Department, a synoptic water-quality study was performed along an 18-kilometer reach of Toll Gate Creek extending from downstream from Quincy Reservoir to the confluence with Sand Creek to develop a detailed understanding of streamflow and concentrations and loads of selenium in Toll Gate Creek. Streamflow and surface-water quality were characterized for summer low-flow conditions (July–August 2007) using four spatially overlapping synoptic-sampling subreaches. Mass-balance methods were applied to the synoptic-sampling and tracer-injection results to estimate streamflow and develop spatial profiles of concentration and load for selenium and other chemical constituents in Toll Gate Creek surface water. Concurrent groundwater sampling determined concentrations of selenium and other chemical constituents in groundwater in areas surrounding the Toll Gate Creek study reaches. Multivariate principal-component analysis was used to group samples and to suggest common sources for dissolved selenium and major ions. Hydrogen and oxygen stable-isotope ratios, groundwater-age interpretations, and chemical analysis of water-soluble paste extractions from core samples are presented, and interpretation of the hydrologic and geochemical data support conclusions regarding geologic sources of selenium and the processes affecting selenium loading in the Toll Gate Creek watershed. Streamflow conditions observed and measured during the synoptic water-quality study represent summer base-flow conditions and rainfall conditions for July 2007. The lack of large tributary inflows and the spatial distribution of small tributary inflows, seeps, and springs indicate that diffuse and discrete groundwater inflow supports streamflow during low-flow conditions along the entire 18-kilometer stream reach. Concentrations of dissolved selenium within all subreaches of Toll Gate Creek exceeded the Colorado aquatic-life standard of 4.6 micrograms per liter in 2007. Concentrations of selenium in the upper portion of the Toll Gate Headwaters subreach (TGH) remained close to the aquatic-life standard at about 5 micrograms per liter. Downstream from a concrete-lined channel section, inflows with selenium concentrations greater than the stream contribute selenium load to surface water. However, stream selenium concentrations were less than 20 micrograms per liter all along Toll Gate Creek. Concentrations of selenium in groundwater were in general substantially greater than the Colorado aquatic-life standard of 4.6 micrograms per liter and at some locations were greater than the U.S. Environmental Protection Agency primary drinking-water standard for selenium of 50 micrograms per liter. The distribution of selenium concentrations in groundwater, springs, and the 11 inflows with the greatest selenium concentrations indicates that shallow groundwater in surficial materials and the Denver Formation bedrock is a source of selenium loading to Toll Gate Creek and that selenium loading is distributed along the entire length of the study reach downstream from the concrete-lined channel. Water-quality and solids-sampling results from this study indicate weathering processes release water-soluble selenium from the underlying Denver Formation claystone bedrock with subsequent cycling of selenium in the aquatic environment of Toll Gate Creek. Exposure of the Denver Formation selenium-bearing bedrock to oxidizing atmospheric conditions, surface water, and groundwater, oxidizes selenide, held as a trace element in pyrite or in complexes with organic matter, to selenite and selenate. Secondary weathering products including iron oxides and selenium-bearing salts have accumulated in the weathered zone in the semiarid climate and also can serve as sources or sinks of selenium. P

Paschke, Suzanne S.; Runkel, Robert L.; Walton-Day, Katherine; Kimball, Briant A.; Schaffrath, Keelin R.

2013-01-01

298

Evolution of U fractionation processes through geologic time : consequences for the variation of U deposit types from Early Earth to Present  

NASA Astrophysics Data System (ADS)

U deposits are known at nearly all stages of the geological cycle, but are not known prior to 2.95 Ga. Also, U deposit types vary greatly from Mesoarchean to Present. Most of these changes through time can be attributed to major modifications in the geodynamic evolution of the Earth, in magmatic fractionation processes, in the composition of the Atmosphere and in the nature of life. The first U-rich granites able to crystallize uraninite, appeared at about 3.1 Ga. They correspond to the most fractionated terms of high-K calcalkaline suites, resulting from crystal fractionation of magmas possibly derived from melting of mantle wedges enriched in K, U, Th. Highly fractionated peraluminous leucogranites, able to crystallize uraninite, appeared at about 2.6 Ga. Erosion of these two granite types led to the detrital accumulation of uraninite that formed the first U deposits on Earth: the Quartz Pebble Conglomerates from 2.95 to 2.4 Ga. From 2.3 Ga onwards, uprise of oxygen level in the atmosphere led to the oxidation of U(IV) to U(VI), U transport in solution, and exuberant development of marine algae in epicontinental platform sediments. From 2.3 to 1.8 Ga large amounts of U, previously accumulated as U(IV) minerals, were dissolved and trapped preferentially in passive margin settings, in organic-rich sediments, and which led to the formation of the world’s largest Paleoproterozoic U provinces, e.g. : the Wollaston belt, Canada and the Cahill Formation, Australia. During and after the worldwide 2.1-1.75 Ga orogenic events, responsible for the formation of the Nuna supercontinent, U trapped in these formations was the source for several types of mineralization: (i) metamorphosed U-mineralized graphitic schists, calcsilicates and meta-arkoses, (ii) diagenetic-hydrothermal remobilization with the formation of the first deposits related to redox processes at 2.0 Ga (Oklo, Gabon), (iii) partial melting of U-rich metasediments forming the uraninite disseminations in pegmatoids (Charlebois, Canada), (iv) hydrothermal remobilization in veins (Beaverlodge, Canada) at about 1.75 Ga, and (v) U mineralization related to Na-metasomatism (Lagoa Real, Brazil ; Central Ukraine). After 1.75 Ga, a long period of tectonic quiescence occurred on the Earth, and large intracontinental basins, comprising at their base thick oxidized siliciclastic sequences were formed in many parts of the Nuna. In the Athabasca (Canada) and Kombolgie (Australia) basins, the siliciclastic sediments represented huge aquitards for sodic brines derived from overlying evaporites. The brines became calcic when infiltrated into the basement and leached U dominantly from Paleoproterozoic epicontinental sediments, their anatectic derivatives and high-K-U granites, to form the unconformity related U deposits. By the end of Silurian, with the apparition of land plants, deposits hosted by continental to marginal marine sandstone (roll front, tabular, tectono-lithologic, paleovalleys) became widespread. The largest volcanic related U-deposits are mostly known during the Mesozoic and calcrete are only known during late Caenozoic to Quaternary, but this may by due to the non preservation from erosion of such deposits formed at very shallow levels.

Cuney, M.

2009-12-01

299

Carbon dioxide reaction processes in a model brine aquifer at 200 °C and 200 bars: implications for geologic sequestration of carbon  

Microsoft Academic Search

The reactive behavior of supercritical CO2 under conditions relevant to geologic storage and sequestration of C is largely unknown. Experiments were conducted in a flexible cell hydrothermal apparatus to determine the extent of fluid–rock reactions, in addition to carbonate mineral precipitation, that may occur in a brine aquifer–aquitard system that simulates a saline aquifer storage scenario. The system was held

John P. Kaszuba; David R. Janecky; Marjorie G. Snow

2003-01-01

300

Distributed process-based models of mountain permafrost: the importance of accurate spatial input and calibration data.  

NASA Astrophysics Data System (ADS)

Process-based modeling improves our understanding of the response of permafrost to climate change and provides a means for estimating ground temperatures spatially as well as in their temporal evolution. However, increasing complexity of models results in the need for quantitative spatial input and calibration. Corresponding developments are presented. PERMEBAL is a model of the atmosphere-cryosphere interaction in complex topography developed at the University of Zurich, Switzerland in recent years. Driven by extrapolated meteorological data, a one-dimensional daily energy balance at the ground surface including accumulation and melt of the snow pack is approximated for a large number of grid cells based on a digital elevation model. Ground temperatures and energy fluxes can be computed in the form of spatial data fields or time series. The comparison of independent micro-meteorological measurements with model results provides a means to assess the absolute accuracy of calculated fluxes and confirms the suitability of the modeling approach. However, to apply the model to a grid, important spatially-variable parameters such as albedo need to be measured for each cell and the model needs to be verified in the spatial dimension. As a consequence, the further use and development of the model requires calibration points representing a wide range of conditions in the area in order to evaluate final ground temperatures. Despite their importance, coarse blocky surfaces and rock glaciers are least suitable for model calibration. This is due to the many unknowns introduced by a mixed-media active layer and the presence of snow cover, which has a complex influence on ground temperatures. A layered calibration approach is proposed using measurements in increasingly complicated situations: (a) steep rock faces (no snow cover, direct coupling of surface and sub-surface); (b) gently sloping glacier-polished rock (snow cover) and (c) coarse blocky surfaces. This will provide a means to narrow-in on inaccuracies in the model and to investigate the spatial patterns of surface temperatures. First results from a corresponding campaign using rock-face measurements are presented. Improving the simulation and our understanding of spatial surface temperature distributions will likely require increasingly well-designed combinations of systematic measurements, modeling, verification/calibration and sensitivity studies.

Gruber, S.; Hoelzle, M.; Haeberli, W.

2003-04-01

301

Geologic Measurements using Rover Images: Lessons from Pathfinder with Application to Mars 2001  

NASA Technical Reports Server (NTRS)

The Pathfinder Sojourner rover successfully acquired images that provided important and exciting information on the geology of Mars. This included the documentation of rock textures, barchan dunes, soil crusts, wind tails, and ventifacts. It is expected that the Marie Curie rover cameras will also successfully return important information on landing site geology. Critical to a proper analysis of these images will be a rigorous determination of rover location and orientation. Here, the methods that were used to compute rover position for Sojourner image analysis are reviewed. Based on this experience, specific recommendations are made that should improve this process on the '01 mission.

Bridges, N. T.; Haldemann, A. F. C.; Herkenhoff, K. E.

1999-01-01

302

Geologic evolution of the terrestrial planets  

NASA Technical Reports Server (NTRS)

The paper presents a geologic comparison of the terrestrial planets Mercury, Venus, Earth, the Moon and Mars, in the light of the recent photogeologic and other evidence gathered by satellites, and discusses the relationships between their regional terrain types, ages, and planetary evolution. The importance of the two fundamental processes, impact cratering and volcanism, which had formed these planets are stressed and the factors making the earth unique, such as high planetary evolution index (PEI), dynamic geological agents and the plate tectonics, are pointed out. The igneous processes which dominate earth and once existed on the others are outlined together with the planetary elevations of the earth which has a bimodal distribution, the moon which has a unimodal Gaussian distribution and Mars with a distribution intermediate between the earth and moon. Questions are raised concerning the existence of a minimum planetary mass below which mantle convection will not cause lithospheric rifting, and as to whether each planet follows a separate path of evolution depending on its physical properties and position within the solar system.

Head, J. W.; Mutch, T. A.; Wood, C. A.

1977-01-01

303

Geology and the environment in Kenya  

NASA Astrophysics Data System (ADS)

Kenya is in a unique environmental setting by virtue of its geographical location, range of altitudes and perhaps most importantly, the Great Rift System that traverses it. The country displays virtually every facet of environmental geological phenonmena — seismicity, volcanism, mass-movements, the impact of mining, mineral processing and geothermal energy resources development, soil and beach erosion, desertification, air, water and soil pollution, etc. A significant mass of data on these topics already exists, but it lies scattered in various journals and agency reports, some of which are not readily available to environmental researchers and country-planners. The aim of this paper, therefore, is to highlight some features of geology and the environment in Kenya and to set the scene for the subsequent papers in this issue, which examine more deeply various aspects of the subject. The uniqueness of the country's environmental setting is emphasised throughout, since it gives it a special appeal to geomorphologists, geophysicists, hydrologists and land-use planners. A comprehensive list of references is given at the end of this paper in order to aid the search process of those who seek additional information on areas covered in this review.

Mathu, E. M.; Davies, T. C.

1996-11-01

304

Mineral Resources, Geological Structure and Landform Surveys  

NASA Technical Reports Server (NTRS)

Significant results are presented of ERTS-1 investigations of landform surveys, mineral resources, and geological structures. The report covers four areas: (1) mapping investigations; (2) dynamic surface processes and landforms; (3) structural elements; and (4) mineral deposits.

Short, M. N.

1973-01-01

305

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

306

Geology. Grade 6. Anchorage School District Elementary Science Program.  

ERIC Educational Resources Information Center

This resource book introduces sixth-grade children to the environment by studying rocks and other geological features. Nine lessons are provided on a variety of topics including: (1) geologic processes; (2) mountain building; (3) weathering; (4) geologic history and time; (5) plate tectonics; (6) rocks and minerals; (7) mineral properties; (8)…

Anchorage School District, AK.

307

Successful Drug Development Despite Adverse Preclinical Findings Part 1: Processes to Address Issues and Most Important Findings  

PubMed Central

Unexpected adverse preclinical findings (APFs) are not infrequently encountered during drug development. Such APFs can be functional disturbances such as QT prolongation, morphological toxicity or carcinogenicity. The latter is of particular concern in conjunction with equivocal genotoxicity results. The toxicologic pathologist plays an important role in recognizing these effects, in helping to characterize them, to evaluate their risk for man, and in proposing measures to mitigate the risk particularly in early clinical trials. A careful scientific evaluation is crucial while termination of the development of a potentially useful drug must be avoided. This first part of the review discusses processes to address unexpected APFs and provides an overview over typical APFs in particular classes of drugs. If the mode of action (MoA) by which a drug candidate produces an APF is known, this supports evaluation of its relevance for humans. Tailor-made mechanistic studies, when needed, must be planned carefully to test one or several hypotheses regarding the potential MoA and to provide further data for risk evaluation. Safety considerations are based on exposure at no-observed-adverse-effect levels (NOAEL) of the most sensitive and relevant animal species and guide dose escalation in clinical trials. The availability of early markers of toxicity for monitoring of humans adds further safety to clinical studies. Risk evaluation is concluded by a weight of evidence analysis (WoE) with an array of parameters including drug use, medical need and alternatives on the market. In the second part of this review relevant examples of APFs will be discussed in more detail. PMID:22272031

Kuroda, Junji; Plassmann, Stephanie; Prentice, David E.

2010-01-01

308

GEOL 4501 - Geology Seminar The Geologic Record of Climate Change Spring 2009  

Microsoft Academic Search

DESCRIPTION: In this seminar course, we will explore the geologic record of pre- Holocene climate change. The geologic record preserves numerous lines of evidence for ancient climate change that record, with varying degrees of fidelity, the numerous climatic changes experienced by the Earth during its 4.5 billion year history. We will examine several important intervals of climate change in ?deep

Julie Bartley

309

Geology and our future: summary of a workshop report  

SciTech Connect

This report highlights the significance of the geological sciences to the nation and to society. Discussions include understanding plate tectonics and surface processes, exploring the continental crust, ocean basins and the deep earth, applications of geology to social problems such as mineral resources, waste disposal, siting of critical facilities, geological hazards, water resources management, and coastal zones. The state of health of geological research is also discussed. (ACR)

Not Available

1983-01-01

310

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.

311

The importance of ‘process’ in Rethinking Project Management: The story of a UK Government-funded research network  

Microsoft Academic Search

This paper tells the story of a UK Government-funded research network called Rethinking Project Management, funded by the Engineering and Physical Sciences Research Council between 2004 and 2006. The story is significant because of the considerable attention given to the process of the Network, both the inquiry process of ‘rethinking’ project management, and the broader social process in which the

Mark Winter; Charles Smith; Terry Cooke-Davies; Svetlana Cicmil

2006-01-01

312

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

313

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

314

Structural Geology 'Research' Conference  

NSDL National Science Digital Library

In this assignment students read and discuss a peer-reviewed journal article and prepare for and attend our class 'research' conference. In the conference they present on an area of current research as discussed in the journal article they read, and they practice formulating questions about other's research. Outcomes: 1. Read and discuss a structural geology peer-reviewed journal article. 2. Prepare a presentation that demonstrates your understanding of a current research topic in structural geology. 3. View and understand several diverse areas within geology and geophysics that use structural geology in research. 4. Ask questions relevant to a research presentation.

Willis, Julie

315

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

316

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.

317

CO{sub 2} Geologic Storage: Coupled Hydro-Chemo-Thermo-Mechanical Phenomena - From Pore-scale Processes to Macroscale Implications -  

SciTech Connect

Global energy consumption will increase in the next decades and it is expected to largely rely on fossil fuels. The use of fossil fuels is intimately related to CO{sub 2} emissions and the potential for global warming. Geological CO{sub 2} storage aims to mitigate the global warming problem by sequestering CO{sub 2} underground. Coupled hydro-chemo-mechanical phenomena determine the successful operation and long term stability of CO{sub 2} geological storage. This research explores coupled phenomena, identifies different zones in the storage reservoir, and investigates their implications in CO{sub 2} geological storage. In particular, the research: Explores spatial patterns in mineral dissolution and precipitation (comprehensive mass balance formulation); experimentally determines the interfacial properties of water, mineral, and CO{sub 2} systems (including CO{sub 2}-water-surfactant mixtures to reduce the CO{sub 2}- water interfacial tension in view of enhanced sweep efficiency); analyzes the interaction between clay particles and CO{sub 2}, and the response of sediment layers to the presence of CO{sub 2} using specially designed experimental setups and complementary analyses; couples advective and diffusive mass transport of species, together with mineral dissolution to explore pore changes during advection of CO{sub 2}-dissolved water along a rock fracture; upscales results to a porous medium using pore network simulations; measures CO{sub 2} breakthrough in highly compacted fine-grained sediments, shale and cement specimens; explores sealing strategies; and experimentally measures CO{sub 2}-CH{sub 4} replacement in hydrate-bearing sediments during. Analytical, experimental and numerical results obtained in this study can be used to identify optimal CO{sub 2} injection and reservoir-healing strategies to maximize the efficiency of CO{sub 2} injection and to attain long-term storage.

Santamarina, J. Carlos

2013-05-31

318

$gamma$RAY PROCESSING OF RICE. (I.) THE EFFECT OF $gamma$IRRADIATION ON IMPORTED RICE STARCH  

Microsoft Academic Search

A study of the effect of gamma irradiation on imported rice starch ; showed that the intrinsic viscosity and blue value of starch-iodine color ; reaction decreased, while the reducing power, alkali liability number, and ; digestibility increased. A change in the viscogram curve was also noted. Gamma ; irradiation degraded the straight chain components of the imported rice starch

Takaoka

1960-01-01

319

A program for mass spectrometer control and data processing analyses in isotope geology; written in BASIC for an 8K Nova 1120 computer  

USGS Publications Warehouse

A system is described which uses a minicomputer to control a surface ionization mass spectrometer in the peak switching mode, with the object of computing isotopic abundance ratios of elements of geologic interest. The program uses the BASIC language and is sufficiently flexible to be used for multiblock analyses of any spectrum containing from two to five peaks. In the case of strontium analyses, ratios are corrected for rubidium content and normalized for mass spectrometer fractionation. Although almost any minicomputer would be suitable, the model used was the Data General Nova 1210 with 8K memory. Assembly language driver program and interface hardware-descriptions for the Nova 1210 are included.

Stacey, J.S.; Hope, J.

1975-01-01

320

40 CFR 761.193 - Maintenance of monitoring records by persons who import, manufacture, process, distribute in...  

Code of Federal Regulations, 2010 CFR

...containing inadvertently generated PCBs. 761.193 Section 761...TOXIC SUBSTANCES CONTROL ACT POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING...containing inadvertently generated PCBs. (a) Persons who...

2010-07-01

321

Geologic Time: The Story of a Changing Earth  

NSDL National Science Digital Library

ItâÂÂs hard imagining how one could fit the entirety of geologic time onto one website, but the staff members of the department of paleobiology at the Smithsonian National Museum of Natural History have done an excellent job with this site. The intent of the site is to provide an interactive timeline of geological history, beginning with the Hadean eon and proceeding all the way to the current day. After a compelling introductory section, visitors are led into the elegant timeline interface which allows them to explore the siteâÂÂs primary contents. Using a drag tool, visitors can move around the span of the different geological eons, eras, periods, and epochs in a direct fashion. Clicking on each of the icons within each division of time brings up a brief overview of each segment, along with a map of each period, complete with various renderings of the conditions that existed on the Earth at the time. Visitors will also appreciate the âÂÂFoundational Conceptsâ area, which provides a foundation for understanding the nature of geology, such as the importance of different dating methods and earth processes. Overall, this site is extraordinarily helpful, both for the general public and for more seasoned amateur geologists.

322

Geologic Time: The Story of a Changing Earth  

NSDL National Science Digital Library

It's hard imagining how one could fit the entirety of geologic time onto one website, but the staff members of the department of paleobiology at the Smithsonian National Museum of Natural History have done an excellent job with this site. The intent of the site is to provide an interactive timeline of geological history, beginning with the Hadean eon and proceeding all the way to the current day. After a compelling introductory section, visitors are led into the elegant timeline interface which allows them to explore the site's primary contents. Using a drag tool, visitors can move around the span of the different geological eons, eras, periods, and epochs in a direct fashion. Clicking on each of the icons within each division of time brings up a brief overview of each segment, along with a map of each period, complete with various renderings of the conditions that existed on the Earth at the time. Visitors will also appreciate the "Foundational Concepts" area, which provides a foundation for understanding the nature of geology, such as the importance of different dating methods and earth processes. Overall, this site is extraordinarily helpful, both for the general public and for more seasoned amateur geologists.

2006-01-11

323

Two-step Processing Is Not Essential for the Import and Assembly of Functionally Active Iron-Sulfur Protein into the Cytochrome bc1  

E-print Network

Two-step Processing Is Not Essential for the Import and Assembly of Functionally Active Iron-Sulfur From the Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755 The iron-sulfur for import and assembly of the iron-sulfur protein into the cytochrome bc1 complex, we mutagenized the prese

Trumpower, Bernard L.

324

Multivariate Models of Parent-Late Adolescent Gender Dyads: The Importance of Parenting Processes in Predicting Adjustment  

Microsoft Academic Search

Although parent-adolescent interactions have been examined, relevant variables have not been integrated into a multivariate\\u000a model. As a result, this study examined a multivariate model of parent-late adolescent gender dyads in an attempt to capture\\u000a important predictors in late adolescents’ important and unique transition to adulthood. The sample for this study consisted\\u000a of 151 male and 324 female late adolescents,

Cliff McKinney; Kimberly Renk

2008-01-01

325

Principle and geometric precision of photographic geological logging of tunnels  

NASA Astrophysics Data System (ADS)

Considering the problem of engineering geological logging technique by means of sketching at the work site, this paper presents a photographic geological logging technique based on photogrammetry as well as engineering geology. The principles, methods, and working process have been discussed, and the photographic geological logging precision of a tunnel and its estimation method have been researched. The theoretical and experimental analysis shows that the precision of the digital unfolded image map of tunnel automatically generated by the photographic geological logging method is sufficient for serving as the logging base map. Besides, the measurement precision of unfolded images or stereopairs meets the requirements of geological attitude measurement. The new technique of photographic geological logging proposed in this paper is expected to replace the current sketch way of engineering geological logging on site, with the operation mode converted from manual operation to computer-aided operation and informatized management.

Li, Hao; Zhang, Rong-Chun; Yang, Biao; Wu, Ming-Fei

2014-01-01

326

Earthquakes and Geology  

NSDL National Science Digital Library

In this activity, students investigate the relationship between intensity of ground motion and type of rock or alluvium, as seen in the 1994 Northridge, California earthquake. They will examine a map of Mercalli intensity, a cross-section showing geologic structures and rock types, and a map of surficial geology, and answer questions pertaining to amplification of ground motion and S-wave velocities.

Ozsvath, David

327

Structural Geology Techniques  

NSDL National Science Digital Library

The University of Wisconsin - Green Bay has created this collection of material and instructions on how to analyze and plot structural geology data. Topics covered includes planes, lines, relations between lines and planes, geologic structures, intersection of structures with topography, stereonet techniques, stress and strain, and analysis of complex structures.

Dutch, Steven

2009-05-21

328

Geologic mapping of Europa  

Microsoft Academic Search

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

Ronald Greeley; Patricio H. Figueredo; David A. Williams; Frank C. Chuang; James E. Klemaszewski; Steven D. Kadel; Louise M. Prockter; Robert T. Pappalardo; James W. Head; Geoffrey C. Collins; Nicole A. Spaun; Robert J. Sullivan; Jeffrey M. Moore; David A. Senske; B. Randall Tufts; Torrence V. Johnson; Michael J. S. Belton; Kenneth L. Tanaka

2000-01-01

329

Advances in Planetary Geology  

NASA Technical Reports Server (NTRS)

Advances in Planetary Geology is a new series intended to serve the planetary geology community with a form for quick and thorough communications. There are no set lists of acceptable topics or formats, and submitted manuscripts will not undergo a formal review. All submissions should be in a camera ready form, preferably spaced, and submitted to the editor.

Woronow, A. (editor)

1982-01-01

330

Geology in America  

Microsoft Academic Search

I AM somewhat chagrined to find that I appear to you (vol. xi. p. 381) to say that the Geological Survey of Great Britain is especially to blame for the diminution of interest in geology in the country that has done the most for its advancement. My remarks were taken down by a reporter, and I have not seen them

N. S. Shaler

1875-01-01

331

Geology of the Caribbean.  

ERIC Educational Resources Information Center

Describes some of the geologic characteristics of the Caribbean region. Discusses the use of some new techniques, including broad-range swath imaging of the sea floor that produces photograph-like images, and satellite measurement of crustal movements, which may help to explain the complex geology of the region. (TW)

Dillon, William P.; And Others

1988-01-01

332

Forensic geology exhumed  

Microsoft Academic Search

Forensic geology binds applied geology to the world of legal controversy and action. However, the term ``forensic'' is often misconstrued. Although even some attorneys apply it only to the marshalling of evidence in criminal cases, it has a much broader definition. One dictionary defines it as ``pertaining to, connected with, or used in courts of law or public discussion and

Joseph Didier Martinez

1991-01-01

333

Geological data bases combine  

Microsoft Academic Search

In a move designed to eliminate overlap and increase coverage of scholarly publications, three major institutions have agreed to pool their resources in compiling a common geological bibliographic data base. The American Geological Institute (AGI), the Bureau de Recherches Geologiques et Minieres (BRGM), and the Centre National de la Recherche Scientifique (CNRS) will begin producing a joint bibliographic record in

Lee Greathouse

1980-01-01

334

Glossary of geology  

SciTech Connect

This third edition of the Glossary of Geology contains approximately 37,000 terms, or 1,000 more than the second edition. New entries are especially numerous in the fields of carbonate sedimentology, hydrogeology, marine geology, mineralogy, ore deposits, plate tectonics, snow and ice, and stratigraphic nomenclature. Many of the definitions provide background information.

Bates, R.L.; Jackson, J.A.

1987-01-01

335

External Resource: Geologic Time  

NSDL National Science Digital Library

This NASA sponsored webpage, Center for Educational Technologies, teaches students about Geologic Time. The age of Earth is so long compared to all periods of time that we humans are familiar with, it has been given a special name: Geologic time. The age

1900-01-01

336

Geologic time scale bookmark  

USGS Publications Warehouse

This bookmark, designed for use with U.S. Geological Survey activities at the 2nd USA Science and Engineering Festival (April 26–29, 2012), is adapted from the more detailed Fact Sheet 2010–3059 "Divisions of Geologic Time." The information that it presents is widely sought by educators and students.

U.S. Geological Survey

2012-01-01

337

People and Geology.  

ERIC Educational Resources Information Center

Provides background information on the many natural resources we extract from the earth's crust, including metals, graphite, and other minerals, as well as fossil fuels. Contains teaching activities such as a geologic scavenger hunt, a geology chronology, and the recycling of aluminum. Includes a reproducible handout for the activity on aluminum.…

Naturescope, 1987

1987-01-01

338

Dione's spectral and geological properties  

USGS Publications Warehouse

We present a detailed analysis of the variations in spectral properties across the surface of Saturn's satellite Dione using Cassini/VIMS data and their relationships to geological and/or morphological characteristics as seen in the Cassini/ISS images. This analysis focuses on a local region on Dione's anti-saturnian hemisphere that was observed by VIMS with high spatial resolution during orbit 16 in October 2005. The results are incorporated into a global context provided by VIMS data acquired within Cassini's first 50 orbits. Our results show that Dione's surface is dominated by at least one global process. Bombardment by magnetospheric particles is consistent with the concentration of dark material and enhanced CO2 absorption on the trailing hemisphere of Dione independent of the geology. Local regions within this terrain indicate a special kind of resurfacing that probably is related to large-scale impact process. In contrast, the enhanced ice signature on the leading side is associated with the extended ejecta of the fresh impact crater Creusa (???49??N/76??W). Although no geologically active regions could be identified, Dione's tectonized regions observed with high spatial resolution partly show some clean H2O ice implying that tectonic processes could have continued into more recent times. ?? 2009 Elsevier Inc. All rights reserved.

Stephan, K.; Jaumann, R.; Wagner, R.; Clark, R.N.; Cruikshank, D.P.; Hibbitts, C.A.; Roatsch, T.; Hoffmann, H.; Brown, R.H.; Filiacchione, G.; Buratti, B.J.; Hansen, G.B.; McCord, T.B.; Nicholson, P.D.; Baines, K.H.

2010-01-01

339

Editor's Note: Geology Is Fundamental (December 2006)  

NSDL National Science Digital Library

Geology is fundamental. The usual triad of sciences (chemistry, physics, and biology) is also clearly important. Not much can be explained without physics, for example. But geology, the history of Earth, is an application of these sciences that deserves more attention. It can be immediately seen around us whether we live in Arizona or Iowa. This issue presents lessons that will introduce Earth science concepts to your students and make them applicable in your classroom.

Ohana, Chris

2006-12-01

340

Wyoming State Geological Survey  

NSDL National Science Digital Library

This agency's mission is to study, examine, and seek an understanding of the geology, mineral resources, and physical features of the State; to prepare, publish, and distribute reports and maps of Wyoming's geology, mineral resources, and physical features; and to provide information, advice, and services related to the geology, mineral resources, and physical features of the State. This site contains details and reports about metals in Wyoming, earthquakes and other hazards, coal, industrial minerals, uranium, oil and gas. The field trip section contains details about various areas to visit with students and gives a general geologic description. There is also a searchable bibliography with publications about Wyoming geology. Links are provided for additional resources.

341

Disturbance by large herbivores alters the relative importance of the ecological processes that influence the assembly pattern in heterogeneous meta-communities  

PubMed Central

Disturbance caused by large herbivores can affect the relative importance of ecological processes in determining community assembly and may cause a systematic loss of biodiversity across scales. To examine changes in the community assembly pattern caused by an overabundance of large herbivores in Japan, we analyzed community composition data from before and after the overabundance occurred. The community assembly pattern becomes more random after the deer overabundance. In addition, result of variation partitioning revealed decrease in importance of environmental processes and increase in importance of spatial processes. However, response of turnover rate, niche breadth, and niche overlap was heterogeneous, according to scale of each environmental gradient. Our results emphasize the importance of conserving habitat specialists that represent the local environment (habitat type and topography) at various altitudinal ranges to maintain biodiversity at regional scales under the increasing pressure of large herbivores. PMID:24683459

Ohashi, Haruka; Hoshino, Yoshinobu

2014-01-01

342

Potential of Microbes to Increase Geologic CO2 Storage Security  

NASA Astrophysics Data System (ADS)

Geologic Carbon Capture and Storage (CCS) involves the injection of supercritical CO2 into underground formations such as brine aquifers where microbe-rock-fluid interactions will occur. These interactions may be important for the long-term fate of the injected CO2. Concepts and results will be presented from bench to meso-scale experiments focusing on the utility of attached microorganisms and biofilms to enhance storage security of injected CO2, via mineral-trapping, solubility trapping, formation trapping, and leakage reduction. Batch and flow experiments at atmospheric and geologic CO2 storage-relevant pressures have demonstrated the ability of microbial biofilms to decrease the permeability of natural and artificial porous media, survive the exposure to scCO2, and facilitate the conversion of CO2 into long-term stable carbonate phases as well as increase the solubility of CO2 in brines. Recent work has focused on small and large scale (75 cm diameter, 38 cm high sandstone) radial flow systems as well as the molecular characterization and isolation of microbes from geologic carbon sequestration-relevant environments. Methods for microscopic and macroscopic visualization of relevant processes from the pore to the bulk scale are being developed and have been proven to be essential tools in establishing the necessary understanding to increase CO2 storage security. As a result, reactive transport models describing the influence of biological processes on CO2 storage security have been developed and are continuously being modified to include relevant processes.

Gerlach, R.; Mitchell, A. C.; Ebigbo, A.; Phillips, A.; Cunningham, A. B.

2011-12-01

343

HIV1 infection of non-dividing cells: evidence that the amino-terminal basic region of the viral matrix protein is important for Gag processing but not for post-entry nuclear import  

Microsoft Academic Search

Human immunodeficiency virus type-1 (HIV-1) is able to infect non-dividing cells such as tissue macrophages productively because post-entry viral nucleoprotein complexes are specifically imported into the nucleus in the absence of mitosis. Although it has been proposed that an amino-terminal region of the viral matrix (MA, p17Gag) protein harbors a basic-type nuclear localization sequence (NLS) that contributes to this process,

Ron A. M. Fouchier; Barbara E. Meyer; James H. M. Simon; Utz Fischer; Michael H. Malim

1997-01-01

344

Significant achievements in the planetary geology program, 1981  

NASA Technical Reports Server (NTRS)

Recent developments in planetology research as reported at the 1981 NASA Planetary Geology Principal Investigators meeting are summarized. The evolution of the solar system, comparative planetology, and geologic processes active on other planets are considered. Galilean satellites and small bodies, Venus, geochemistry and regoliths, volcanic and aeolian processes and landforms, fluvial and periglacial processes, and planetary impact cratering, remote sensing, and cartography are discussed.

Holt, H. E. (editor)

1981-01-01

345

OneGeology-Europe: architecture, portal and web services to provide a European geological map  

NASA Astrophysics Data System (ADS)

OneGeology-Europe is a large ambitious project to make geological spatial data further known and accessible. The OneGeology-Europe project develops an integrated system of data to create and make accessible for the first time through the internet the geological map of the whole of Europe. The architecture implemented by the project is web services oriented, based on the OGC standards: the geological map is not a centralized database but is composed by several web services, each of them hosted by a European country involved in the project. Since geological data are elaborated differently from country to country, they are difficult to share. OneGeology-Europe, while providing more detailed and complete information, will foster even beyond the geological community an easier exchange of data within Europe and globally. This implies an important work regarding the harmonization of the data, both model and the content. OneGeology-Europe is characterised by the high technological capacity of the EU Member States, and has the final goal to achieve the harmonisation of European geological survey data according to common standards. As a direct consequence Europe will make a further step in terms of innovation and information dissemination, continuing to play a world leading role in the development of geosciences information. The scope of the common harmonized data model was defined primarily by the requirements of the geological map of Europe, but in addition users were consulted and the requirements of both INSPIRE and ‘high-resolution' geological maps were considered. The data model is based on GeoSciML, developed since 2006 by a group of Geological Surveys. The data providers involved in the project implemented a new component that allows the web services to deliver the geological map expressed into GeoSciML. In order to capture the information describing the geological units of the map of Europe the scope of the data model needs to include lithology; age; genesis and metamorphic character. For high resolution maps physical properties, bedding characteristics and weathering also need to be added. Furthermore, Geological data held by national geological surveys is generally described in national language of the country. The project has to deal with the multilingual issue, an important requirement of the INSPIRE directive. The project provides a list of harmonized vocabularies, a set of web services to deal with them, and a web site for helping the geoscientists while mapping the terms used into the national datasets into these vocabularies. The web services provided by each data provider, with the particular component that allows them to deliver the harmonised data model and to handle the multilingualism, are the first part of the architecture. The project also implements a web portal that provides several functionalities. Thanks to the common data model implemented by each web service delivering a part of the geological map, and using OGC SLD standards, the client offers the following option. A user can request for a sub-selection of the map, for instance searching on a particular attribute such as "age is quaternary", and display only the parts of the map according to the filter. Using the web services on the common vocabularies, the data displayed are translated. The project started September 2008 for two years, with 29 partners from 20 countries (20 partners are Geological Surveys). The budget is 3.25 M€, with a European Commission contribution of 2.6 M€. The paper will describe the technical solutions to implement OneGeology-Europe components: the profile of the common data model to exchange geological data, the web services to view and access geological data; and a geoportal to provide the user with a user-friendly way to discover, view and access geological data.

Tellez-Arenas, Agnès.; Serrano, Jean-Jacques; Tertre, François; Laxton, John

2010-05-01

346

Siderite formation in anoxic deep-sea sediments: A synergetic bacterially controlled process with important implications in paleomagnetism  

Microsoft Academic Search

Recent work on magnetic properties of limestones has demonstrated that the mineral siderite can be very important in paleomagnetism, for two reasons. First, oxidation of siderite produces secondary (daughter) magnetic minerals (magnetite, maghemite, and hematite), either before, during, or after sampling. These daughter products can completely change the magnetic properties of limestone samples and if unrecognized may be one of

Brooks B. Ellwood; Thomas H. Chrzanowski; Frantisek Hrouda; Gary J. Long; Margaret L. Buhl

1988-01-01

347

7 CFR 361.8 - Cleaning of imported seed and processing of certain Canadian-origin screenings.  

Code of Federal Regulations, 2011 CFR

...screenings. (a) Imported seed that is found to contain noxious weed seeds at a level higher than the tolerances set forth in...or by APHIS; if the seed is found to be within the noxious weed tolerances set forth in § 361.6(b), the seed may be...

2011-01-01

348

7 CFR 361.8 - Cleaning of imported seed and processing of certain Canadian-origin screenings.  

Code of Federal Regulations, 2012 CFR

...screenings. (a) Imported seed that is found to contain noxious weed seeds at a level higher than the tolerances set forth in...or by APHIS; if the seed is found to be within the noxious weed tolerances set forth in § 361.6(b), the seed may be...

2012-01-01

349

7 CFR 361.8 - Cleaning of imported seed and processing of certain Canadian-origin screenings.  

Code of Federal Regulations, 2010 CFR

...screenings. (a) Imported seed that is found to contain noxious weed seeds at a level higher than the tolerances set forth in...or by APHIS; if the seed is found to be within the noxious weed tolerances set forth in § 361.6(b), the seed may be...

2010-01-01

350

Reports of Planetary Geology Program, 1981  

NASA Technical Reports Server (NTRS)

Abstracts of 205 reports from Principal investigators of NASA's Planetary Geology Program succinctly summarize work conducted and reflect the significant accomplishments. The entries are arranged under the following topics: (1) Saturnian satellites; (2) asteroids, comets and Galilean satellites; (3) cratering processes and landform development; (4) volcanic processes and landforms; (5) Aerolian processes and landforms; (6) fluvial, preglacial, and other processes of landform development; (7) Mars polar deposits, volatiles, and climate; (8) structure, tectonics, and stratigraphy; (9) remote sensing and regolith chemistry; (10) cartography and geologic mapping; and (11) special programs.

Holt, H. E. (compiler)

1981-01-01

351

Virtual Tour of Maine Geology  

NSDL National Science Digital Library

This selection of slide shows provides a photographic tour of Maine geology. Users can choose slide shows on surficial, bedrock, and coastal geology; fossils, geologic hazards, groundwater and wells; or mineral collecting, mining, and quarrying.

352

Geologic and structural map of eastern Asia  

SciTech Connect

A synthesis of the onshore and offshore geologic data of eastern Asia, prepared by the Institut Francais du Petrole (IFP), has allowed the construction of geologic and structural maps for this region. These maps include three color sheets (scale = 1:2.5 million) and three plates of geologic and structural cross sections. Located between lat. 4/sup 0/ and 35/sup 0/N, and long. 106/sup 0/ and 132/sup 0/E, the maps cover the following geographic areas: East and South China Sea, Sulu Sea, West Philippine basin and onshore neighboring terrains, Kyushu and Ryukyu Islands, the China margin, Taiwan Island, Vietnam, North West Borneo, and the Philippines. The maps synthesize seismic interpretations, oil well data, geologic work in south Japan, Taiwan, Borneo, and the Philippines, and recent data published between 1976 and 1985. Twenty-four geologic cross sections (scale = 1:1.25 million, vertical exaggeration x 6) intersect ocean margins, important basins, and the different structural domains. They are based on seismic profiles, well data, and available onshore and offshore geologic data. These cross sections show basement composition and structures, different tectonic and sedimentary domains, and the structure and thickness of different sedimentary deposits (such as age, unconformities, and geologic structures). Maps and cross sections will be published in early 1987.

Letouzey, J.; Sage, L.

1986-07-01

353

Water, Water Everywhere! [Narrator] Water, Water Everywhere Water is all around us, and its importance to nearly every process  

E-print Network

Water, Water Everywhere! [Narrator] Water, Water Everywhere Water is all around us, and its naturally as a liquid, gas, and solid. The process by which water moves around the Earth, from the ocean to the atmosphere to the land, and back to the ocean, is called the water cycle. Water regulates climate, storing

Waliser, Duane E.

354

An Assessment of the Economic Importance of the San Carlos Island Shrimp Processing Industry to the Lee County Economy  

E-print Network

to the Lee County Economy Chuck Adams, David Mulkey, and Alan Hodges Food and Resource Economics Department the shrimp processing industry on San Carlos Island contributes to the Lee County economy. Most of the shrimp of the revenues earned on a trip are spent within the Lee County economy. During seasons when shrimp landings

Florida, University of

355

Geology of Earth's Moon  

NSDL National Science Digital Library

First, researchers at the University of California, San Diego discuss the importance of studying earthquakes on the moon, also known as moonquakes, and the Apollo Lunar Seismic Experiment (1). Users can discover the problems scientists must deal with when collecting the moon's seismic data. The students at Case Western Reserve University created the second website to address three missions the Institute of Space and Astronautical Science (ISAS) has planned between now and 2010, including a mission to the moon (2). Visitors can learn about the Lunar-A probe that will be used to photograph the surface of the moon, "monitor moonquakes, measure temperature, and study the internal structure." Next, the Planetary Data Service (PDS) at the USGS offers users four datasets that they can use to create an image of a chosen area of the moon (3). Each dataset can be viewed as a basic clickable map; a clickable map where users can specify size, resolution, and projection; or an advanced version where visitors can select areas by center latitude and longitude. The fourth site, produced by Robert Wickman at the University of North Dakota, presents a map of the volcanoes on the moon and compares their characteristics with those on earth (4). Students can learn how the gravitational forces on the Moon affect the lava flows. Next, Professor Jeff Ryan at the University of South Florida at Tampa supplies fantastic images and descriptive text of the lunar rocks obtained by the Apollo missions (5). Visitors can find links to images of meteorites, terrestrial rocks, and Apollo landings as well. At the Science Channel website, students and educators can find a video clip discussing the geologic studies on the moon along with videos about planets (6). Users can learn about how studying moon rocks help scientists better understand the formation of the earth. Next, the Smithsonian National Air and Space Museum presents its research of "lunar topography, cratering and impacts basins, tectonics, lava flows, and regolith properties" (7). Visitors can find summaries of the characteristics of the moon and the main findings since the 1950s. Lastly, the USGS Astrogeology Research Program provides archived lunar images and data collected between 1965 and 1992 by Apollo, Lunar Orbiter, Galileo, and Zond 8 missions (8). While the data is a little old, students and educators can still find valuable materials about the moon's topography, chemical composition, and geology.

356

Homogenity of geological units with respect to the radon risk in the Walloon region of Belgium.  

PubMed

In the process of mapping indoor radon risk, an important step is to define geological units well-correlated with indoor radon. The present paper examines this question for the Walloon region of Belgium, using a database of more than 18,000 indoor radon measurements. With a few exceptions like the Carboniferous (to be divided into Tournaisian, Visean and Namurian-Westphalian) and the Tertiary (in which all Series may be treated together), the Series/Epoch stratigraphic level is found to be the most appropriate geological unit to classify the radon risk. A further division according to the geological massif or region is necessary to define units with a reasonable uniformity of the radon risk. In particular, Paleozoic series from Cambrian to Devonian show strong differences between different massifs. Local hot-spots are also observed in the Brabant massif. Finally, 35 geological units are defined according to their radon risk, 6 of which still present a clear weak homogeneity. In the case of 4 of these units (Jurassic, Middle Devonian of Condroz and of Fagne-Famenne, Ordovician of the Stavelot massif) homogeneity is moderate, but the data are strongly inhomogeneous for Visean in Condroz and in the Brabant massif. The 35 geological units are used in an ANOVA analysis, to evaluate the part of indoor radon variability which can be attributed to geology. The result (15.4-17.7%) agrees with the values observed in the UK. PMID:24953229

Tondeur, François; Cinelli, Giorgia; Dehandschutter, Boris

2014-10-01

357

New marine geology center  

NASA Astrophysics Data System (ADS)

Marine geologists at Dalhousie University in Halifax, Nova Scotia, have created a new Center for Marine Geology. The formation of the center is part of a university-wide effort to extend interests in marine research in all directions, Director James M. Hall said. The center, formed in April, will be a focus for the expansion of research in marine geology, for the development of marine instrumentation, for the expansion of advanced training of Third World geologists in marine geology, and for the university's interaction with the petroleum industry involved in a major play in the areas off the eastern Canadian shore, Hall said.

358

Journal of Geology  

NSDL National Science Digital Library

From the University of Chicago Press's Journals Division, the Journal of Geology is currently available online free of charge (note: subscription fees may soon apply, but no initiation date is provided). This first-rate technical journal, which publishes "research and theory in geophysics, geochemistry, sedimentology, geomorphology, petrology, plate tectonics, volcanology, structural geology, mineralogy, and planetary sciences" has been in print form since 1893. All of the 1999 issues of the Journal of Geology electronic edition are available here. Internet users can access full-text articles with internal links to references and figures (html, .pdf. .ps).

359

Indiana Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Indiana Geological Survey (IGS). Site materials include information on Earth science issues such as groundwater, mapping, coal and mineral resources, oil and gas, and seismic hazards. There is also information on the geologic time scale and stratigraphic record, rocks and minerals, fossils (including nautiloids of the Ordovician period in Indiana), caves and karst topography in Indiana, and glacial geology. The Geographic Information Ssytems (GIS) and mapping section includes a GIS atlas for the state, an online map viewer, links to the Indiana coal mine information system, petroleum database management system, and a download page where users can access GIS datasets for the state.

360

What is Geologic Time?  

NSDL National Science Digital Library

This webpage of the National Park Service (NPS) and United States Geological Survey (USGS) discusses geologic time and what it represents. Beginning about 4.6 billion years ago and ending in the present day, this site exhibits (to scale) the various eras, periods, eons, and epochs of Earth's history with a downloadable geologic time scale available. Links provide maps of what the Earth looked like at various times in its history, as well as a description of how scientists developed the time scale and how they know the age of the Earth.

361

Mass Extinctions Geology 331  

E-print Network

;Stromatoporoids and Corals sarv.gi.ee/geology/photos.html #12;Rugose Corals #12;Victims · Permian ­ about 50 brachiopods ­ All rugose and tabulate corals ­ All remaining trilobites ­ Nearly all crinoids ­ Nearly all

Kammer, Thomas

362

Photos of structural geology  

NSDL National Science Digital Library

This page contains four categories of structural geology photos: brittle structures, ductile structures, active tectonics, and unconformities. All photos are freely downloadable and are at resolutions sufficient for power point.

Miller, Marli

363

North Dakota Geological Survey  

NSDL National Science Digital Library

This is the homepage of the North Dakota Geological Survey. Site materials include information on the state's oil, gas and coal resources, maps, publications, and regulations. The paleontology page features educational articles, information on fossil collecting, articles about fossil exhibits, and information on the state fossil collection. The state GIS hub creates and distributes digital spatial data that conforms to national mapping standards. The teaching tools page includes illustrations and descriptions of rocks and minerals found in the state, as well as information on meteorites and newsletter articles about teaching North Dakota geology. There are also links to landslide maps, surficial geology maps, and links to other survey publications such as reports, bulletins, field studies, other geological and topographic maps, and information on groundwater resources.

364

Interactive Geologic Timeline Activity  

NSDL National Science Digital Library

In this learning activity, students use a web-based geologic timeline to examine temperature, CO2 concentration, and ice cover data to investigate how climate has changed during the last 715 million years.

University, Environmental L.

365

Economic Geology (Oil & Gas)  

ERIC Educational Resources Information Center

Briefly reviews the worldwide developments in petroleum geology in 1971, including exploration, new fields, and oil production. This report is condensed from the October Bulletin of the American Association of Petroleum Geologists. (PR)

Geotimes, 1972

1972-01-01

366

Devil's Tower Geology  

NSDL National Science Digital Library

This site from the National Park Service briefly addresses the geology of Devil's Tower. The evolution of various theories on the formation of the tower are discussed. A slide show of the emplacement of the tower is also available.

National Park Service (NPS)

367

Reconstructing the Geologic Timeline.  

ERIC Educational Resources Information Center

Reports on the use of a non-traditional approach to constructing a geological timeline that allows students to manipulate data, explore their understanding, and confront misconceptions. Lists possible steps to use in engaging students in this constructivist activity. (DDR)

Hemler, Deb; Repine, Tom

2002-01-01

368

HIV-1 infection of non-dividing cells: evidence that the amino-terminal basic region of the viral matrix protein is important for Gag processing but not for post-entry nuclear import.  

PubMed Central

Human immunodeficiency virus type-1 (HIV-1) is able to infect non-dividing cells such as tissue macrophages productively because post-entry viral nucleoprotein complexes are specifically imported into the nucleus in the absence of mitosis. Although it has been proposed that an amino-terminal region of the viral matrix (MA, p17Gag) protein harbors a basic-type nuclear localization sequence (NLS) that contributes to this process, utilization of three distinct nuclear import assays failed to provide any direct supporting evidence. Instead, we found that disruption of this region (26KK-->TT) reduces the rate at which the viral Gag polyprotein (p55Gag) is post-translationally processed by the viral protease. Consistent with the fact that appropriate proteolytic processing is essential for efficient viral growth in all cell types, we also show that the 26KK-->TT MA mutation is equivalently deleterious to the replication of a primary macrophage-tropic viral isolate in cultures of non-dividing and dividing cells. Taken together, these observations suggest that proteins other than MA supply the NLS(s) that enable HIV-1 to infect non-dividing cells. PMID:9303297

Fouchier, R A; Meyer, B E; Simon, J H; Fischer, U; Malim, M H

1997-01-01

369

Johnston Geology Museum  

NSDL National Science Digital Library

The Johnston Geology Museum is part of the Emporia State University Earth Science Department. There is an online virtual tour of the collection which includes a Cretaceous mosasaur, a giant ground sloth, mastodon bones and tusk, brachiopods, Paleozoic corals, sedimentary structures, minerals and crystals. The Museum contains geological specimens predominantly from Kansas, and include the world famous Hamilton Quarry Fossil Assemblage, the Tri-State Mining Display, petrified tree stumps, and the Hawkins and the Calkins Indian Artifact Collections.

2011-07-07

370

Oahu Geology Field Exercises  

NSDL National Science Digital Library

Three field guides are available to sites of geologic interest on Oahu. One is a visit to a landslide occurring in a neighborhood; another focuses on developing observational skills and determining the sequence of geologic events evident in a stratigraphic section; a third examines features associated with formation of a volcanic tuff ring. The worksheets are designed for teachers to implement as-is or modify for their classes.

371

Interpreting Geologic Sections  

NSDL National Science Digital Library

Athro, Limited is a for-profit corporation that publishes high school and college level biology, earth science, and geology course supplements and independent learning materials on the Web. This site provides instruction in interpreting the order of events in three hypothetical and one real geological section. For each section there is a list of events and an animation of the history of the section once the student has decided on the order of events.

Morris, Paul

372

Geology and Human Health  

NSDL National Science Digital Library

This site contains a variety of educational and supporting materials for faculty teaching in the emerging field of geology and human health. You will find links to internet resources, books, teaching activities, and a group email list, as well as posters, presentations and discussions from the spring 2004 workshop on Geology and Human Health. These resources reflect the contributions of faculty members from across the country and the collections will continue to grow as materials are developed.

373

Technologies for laboratory generation of dust from geological materials.  

PubMed

Dusts generated in the laboratory from soils and sediments are used to evaluate the emission intensities, composition, and environmental and health impacts of mineral aerosols. Laboratory dust generation is also utilized in other disciplines including process control and occupational hygiene in manufacturing, inhalation toxicology, environmental health and epidemiology, and pharmaceutics. Many widely available and/or easily obtainable laboratory or commercial appliances can be used to generate mineral aerosols, and several distinct classes of dust generators (fluidization devices, dustfall chambers, rotating drums/tubes) are used for geological particulate studies. Dozens of different devices designed to create dust from soils and sediments under controlled laboratory conditions are documented and described in this paper. When choosing a specific instrument, investigators must consider some important caveats: different classes of dust generators characterize different properties (complete collection of a small puff of aerosol versus sampling of a representative portion of a large aerosol cloud) and physical processes (resuspension of deposited dust versus in situ production of dust). The quantity "dustiness" has been used in industrial and environmental health research; though it has been quantified in different ways by different investigators, it should also be applicable to studies of geological aerosol production. Using standardized dust-production devices and definitions of dustiness will improve comparisons between laboratories and instruments: lessons learned from other disciplines can be used to improve laboratory research on the generation of atmospheric dusts from geological sources. PMID:16427191

Gill, Thomas E; Zobeck, Ted M; Stout, John E

2006-04-30

374

Engineering considerations for the recovery of cesium from geologic materials  

SciTech Connect

Sorption coefficients for cesium in a variety of media have been compiled from a search of the open literature. The sorption coefficient, or K{sub d}, is a description of a dissolved substance`s tendency to attach to a solid substrate. The compilation of K{sub d}S reported here for cesium demonstrate that this element readily sorbs onto-geological material. As a result of this sorption, the mass transport of cesium in the environment will be retarded. This retarded mass transport, characterized by the retardation factor, can be expected to be significant when compared to water velocities through porous-sorbing medium, such as geologic materials. K{sub d}S for cesium are in the range of 100 m{ell}/g up to 10,000 m{ell}/g. K{sub d}S are also an important parameter in the design of engineered systems for the purpose of recovering cesium from soils. The engineering design is based on a material-balance description of the extraction process. The information presented in this report provides a basis to predict the movement of cesium through geologic materials and also to design and predict the performance of extraction processes such as soil washing.

Whalen, C.

1993-05-18

375

Engineering considerations for the recovery of cesium from geologic materials  

SciTech Connect

Sorption coefficients for cesium in a variety of media have been compiled from a search of the open literature. The sorption coefficient, or K[sub d], is a description of a dissolved substance's tendency to attach to a solid substrate. The compilation of K[sub d]S reported here for cesium demonstrate that this element readily sorbs onto-geological material. As a result of this sorption, the mass transport of cesium in the environment will be retarded. This retarded mass transport, characterized by the retardation factor, can be expected to be significant when compared to water velocities through porous-sorbing medium, such as geologic materials. K[sub d]S for cesium are in the range of 100 m[ell]/g up to 10,000 m[ell]/g. K[sub d]S are also an important parameter in the design of engineered systems for the purpose of recovering cesium from soils. The engineering design is based on a material-balance description of the extraction process. The information presented in this report provides a basis to predict the movement of cesium through geologic materials and also to design and predict the performance of extraction processes such as soil washing.

Whalen, C.

1993-05-18

376

Siderite formation in anoxic deep-sea sediments: A synergetic bacterially controlled process with important implications in paleomagnetism  

SciTech Connect

Recent work on magnetic properties of limestones has demonstrated that the mineral siderite can be very important in paleomagnetism, for two reasons. First, oxidation of siderite produces secondary (daughter) magnetic minerals (magnetite, maghemite, and hematite), either before, during, or after sampling. These daughter products can completely change the magnetic properties of limestone samples and if unrecognized may be one of the primary reasons why many paleomagnetic studies of limestones, especially Paleozoic limestones, are unsuccessful. Second, siderite in weakly magnetized rocks may indicate the potential for successful paleomagnetic results. Because the presence of siderite indicates that the primary magnetic carriers are still intact, appropriate demagnetization methods should yield successful results. The authors conclude that microenvironmental conditions in anoxic marine sediments may permit the formation of siderite from iron (II) produced during bacterial dissimilatory iron reduction.

Ellwood, B.B.; Chrzanowski, T.H. (Univ. of Texas, Arlington (USA)); Hrouda, F. (Geofyzika, Brno (Czechoslovakia)); Long, G.J.; Buhl, M.L. (Univ. of Missouri, Rolla (USA))

1988-11-01

377

A new algorithm for coding geological terminology  

NASA Astrophysics Data System (ADS)

The Geological Survey of The Netherlands has developed an algorithm to convert the plain geological language of lithologic well logs into codes suitable for computer processing and link these to existing plotting programs. The algorithm is based on the "direct method" and operates in three steps: (1) searching for defined word combinations and assigning codes; (2) deleting duplicated codes; (3) correcting incorrect code combinations. Two simple auxiliary files are used. A simple PC demonstration program is included to enable readers to experiment with this algorithm. The Department of Quarternary Geology of the Geological Survey of The Netherlands possesses a large database of shallow lithologic well logs in plain language and has been using a program based on this algorithm for about 3 yr. Erroneous codes resulting from using this algorithm are less than 2%.

Apon, W.

378

Two important mechanisms damaging KH2PO4 crystal processed by ultraprecision fly cutting and their relationships with cutting parameters.  

PubMed

Mid-frequency waviness and subsurface crack are two fundamental factors that damage KH(2)PO(4) (KDP) crystal processed by ultraprecise fly cutting. In this paper, the motif theory and the Fourier model method are used to analyze the influence of the two factors on the laser-induced damage threshold (LIDT) of KDP. Research results indicate that the modulation degrees increase nearly linearly when the waviness amplitude and subsurface crack depth increase, and, meanwhile, the LIDT tends to decrease. The two factors have different effects during different stages of KDP failure. The mean amplitudes of waviness and subsurface damage depth have similar changing regulations with different feeds. From the machining perspective, we need not necessarily know which is more dangerous, because when one factor is controlled, the other one will also be restrained at the same time. In general, smaller feed and cutting depth are benefits for improving the LIDT of KDP. PMID:23736229

Li, Mingquan; Chen, Mingjun; Cheng, Jian; Xiao, Yong; Jiang, Wei

2013-05-20

379

[Importance of lipidic acyl chains in the process of biochemical thermal adaptation of Cunninghamella japonica mucoraceous fungus].  

PubMed

The temperature of C. japonica cultivation influences the lipid content and composition of acyl chains, especially the content of such polyunsaturated acids as linoleic and linolenic. Thermal adaptation is accompanied by the modulation of fatty acid isomeric composition and acyl chain length and, at low temperatures, promotes the appearance of fatty acids uncommon to the fungus, in particular, arachidonic acid. The changes occur on a background of significant alterations in the fungus metabolism (in glucose uptake, ATP content, economic coefficient value, etc.). In experiments on the inhibition of translation with cycloheximide, abrupt temperature change (supraoptimal to cold) did not lead to desaturase de novo synthesis, but rather stimulated the activity of the named enzymes, except for palmitoleoyl-CoA desaturase. In the process of temperature adaptation, polar lipid microviscosity modulating compounds influenced fatty acid acyl chain composition. Microviscosity differences between polar and neutral lipids and correlation to the degree of fatty acid unsaturation during temperature fluctuation were established. PMID:19145975

Feofilova, E P; Kuznetsova, L S

2008-01-01

380

[Assessment of disinfection and sterilization processes in dental practice as an important factors in prevention of infections].  

PubMed

The dental health-care settings is an environment where disease transmission occurs easily. Prevention of cross infection is therefore a crucial aspect of dental practice and dental clinic stuffmust adopt certain basic routines while practicing. Infections may be transmitted in the dental operatory through direct contact with blood, oral fluids or other secretions; via indirect contact with contaminated instruments, equipment or environmental surfaces; or by contact with airborne contaminants present in either droplet splatter or aerosols of oral and respiratory fluids. Strategies to prevent dental patient infections have focused on disinfection and sterilization. This study evaluates basic routines in prevention of cross-infection in the dentistry. The sample comprised 100 dentists, who completed questionnaires. Based on inquires the conditions for disinfection and sterilization of medical devices were assessed. The following issues were taken into consideration: the way of disinfection and preparation of the disinfectants, the localization of disinfection, preparing to disinfection, washing and packing of dental devices, the frequency of disinfection, methods of sterilization and the monitoring system, type of sterilizers and the available cycles. The dental practices are well equiped to proceed the steam sterilization, but 33% of dentists don't know the available cycles in their autoclaves. Only 35% of them made sterilization process protocols. Very common are three failures of instruments disinfections: multiple use of disinfectant, adding of disinfectant, adding new instruments. There is still need for improvement in disinfection and sterilization in dental practice, especially including: monitoring and documentation of sterilization process, proper use of disinfectants according to manufactures instructions, frequent disinfection of surfaces which contact with patients. Dental stuff should take part in advanced training courses about disinfection and sterilization. PMID:20120954

Podgórska, Marta; Jakimiak, Bozenna; Röhm-Rodowald, Ewa; Chojecka, Agnieszka

2009-01-01

381

Adaptive Designs in Phase II Clinical Trials Clinical trials play a very important role in the development process of new therapies. Recently there has  

E-print Network

Trials� ( ) Abstract Clinical trials play a very important role in the development process of new for the implementation of clinical trials. The objective of adaptive designs is to ensure direct and dynamic control of the clinical trials. Under this light, the objective of this thesis is the investigation and the development

Chatziantoniou, Damianos

382

Cell membrane damage and protein interaction induced by copper containing nanoparticles--importance of the metal release process.  

PubMed

Cu-containing nanoparticles are used in various applications in order to e.g. achieve antimicrobial activities and to increase the conductivity of fluids and polymers. Several studies have reported on toxic effects of such particles but the mechanisms are not completely clear. The aim of this study was to investigate the interactions between cell membranes and well-characterized nanoparticles of CuO, Cu metal, a binary Cu-Zn alloy and micron-sized Cu metal particles. This was conducted via in vitro investigations of the effects of the nanoparticles on (i) cell membrane damage on lung epithelial cells (A549), (ii) membrane rupture of red blood cells (hemolysis), complemented by (iii) nanoparticle interaction studies with a model lipid membrane using quartz crystal microbalance with dissipation monitoring (QCM-D). The results revealed that nanoparticles of the Cu metal and the Cu-Zn alloy were both highly membrane damaging and caused a rapid (within 1h) increase in membrane damage at a particle mass dose of 20 ?g/mL, whereas the CuO nanoparticles and the micron-sized Cu metal particles showed no such effect. At similar nanoparticle surface area doses, the nano and micron-sized Cu particles showed more similar effects. The commonly used LDH (lactate dehydrogenase) assay for analysis of membrane damage was found impossible to use due to nanoparticle-assay interactions. None of the particles induced any hemolytic effects on red blood cells when investigated up to high particle concentrations (1mg/mL). However, both Cu and Cu-Zn nanoparticles caused hemoglobin aggregation/precipitation, a process that would conceal a possible hemolytic effect. Studies on interactions between the nanoparticles and a model membrane using QCM-D indicated a small difference between the investigated particles. Results of this study suggest that the observed membrane damage is caused by the metal release process at the cell membrane surface and highlight differences in reactivity between metallic nanoparticles of Cu and Cu-Zn and nanoparticles of CuO. PMID:23891735

Karlsson, Hanna L; Cronholm, Pontus; Hedberg, Yolanda; Tornberg, Malin; De Battice, Laura; Svedhem, Sofia; Wallinder, Inger Odnevall

2013-11-01

383

Appraising U.S. Geological Survey science records  

USGS Publications Warehouse

The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center has legislative charters to preserve and make accessible land remote sensing records important to the United States. This essay explains the appraisal process developed by EROS to ensure the science records it holds and those offered to it align with those charters. The justifications behind the questions employed to weed and to complement the EROS archive are explained along with the literature reviewed supporting their inclusion. Appraisal results are listed by individual collection and include the recommendations accepted by EROS management. Reprinted by permission of the publisher.

Faundeen, John L.

2010-01-01

384

XAFS determination of the chemical form of lead in smelter-contaminated soils and mine tailings: Importance of adsorption processes  

SciTech Connect

The authors investigated smelter-contaminated soils from Evin-Malmaison, Nord-Pas-de-Calais, France, and mine tailings from Leadville, Colorado, U.S.A. Bulk Pb concentrations range from 460 to 1900 ppm in the topsoils at Evin-Malmaison site and from 6000 to 10,000 ppm in the tailings samples from the Leadville site. These concentrations necessarily raise human health and environmental concerns, but bioavailability and chemical lability of Pb in these materials vary dramatically and show little correlation with bulk concentrations. This study provides detailed information on the speciation of Pb in these materials. Emphasis is on the identification and characterization of poorly crystalline and/or fine-grained species, such as sorption complexes and poorly crystalline (co)precipitates, which are likely to control Pb bioavailability and mobility in these natural systems. In the Evin-Malmaison samples, direct spectroscopic evidence for Pb sorbed to humic acids was found, as well as to both manganese and iron (oxyhydr)oxides. In the Leadville samples, variations in Pb speciation with pH are consistent with predictions based on simplified model system studies of adsorption processes; specifically, the carbonate-buffered tailings with near-neutral pH contain up to 50% of total Pb as adsorption complexes on iron (oxyhydr)oxides, whereas Pb speciation in sulfide-rich low pH samples is dominated by Pb-bearing jarosites with no evidence for adsorbed Pb in these latter samples.

Morin, G.; Juillot, F.; Ildefonse, P.; Calas, G. [Univ. de Paris 6 et 7 (France). Lab. de Mineralogie-Cristallographie; Ostergren, J.D. [Stanford Univ., CA (United States). Dept. of Geological and Environmental Sciences; Brown, G.E. Jr. [Stanford Univ., CA (United States). Dept. of Geological and Environmental Sciences]|[Stanford Synchrotron Radiation Lab., CA (United States)

1999-03-01

385

Quantifying the importance of the atmospheric sink for polychlorinated dioxins and furans relative to other global loss processes  

NASA Astrophysics Data System (ADS)

Previous attempts to establish global mass balances for polychlorinated dioxins and furans (PCDD/Fs) have focused on the terrestrial sink, thereby neglecting deposition to the oceans and atmospheric losses. In this study, the atmospheric sink of polychlorinated dioxins and furans (PCDD/Fs) was calculated on the basis of their presence in soils. OH radical ([OH]) depletion reactions compete with atmospheric deposition fluxes for the fate of atmospheric PCDD/Fs. Three different steady state scenarios were considered: scenario A was a one-box atmosphere with globally averaged [OH], temperature (T), atmospheric lifetime (tlife), and a constant gas-particle partitioning (?); in scenario B, [OH], T, and ? were averaged in a multibox atmosphere, with a constant tlife; and in scenario C, tlife was varied. In scenario A the strength of the atmospheric sink was 2400-2800 kg/yr; in scenario B it was ˜2100 kg/yr; in scenario C, it was ˜1,800 kg/yr (tlife = 5.4 days) to ˜2,800 kg/yr (tlife = 14 days). The majority of the atmospheric sink was due to the depletion of Cl4DFs (1300-1400 kg/yr), followed by Cl4DDs (360-380 kg/yr) and Cl5DFs (230-240 kg/yr). On a global scale, major sinks for PCDD/Fs are the deposition to terrestrial soils and the oceans. For Cl6-8DDs, deposition to soils outweighs depletion reactions in the atmosphere and ocean uptake. The more volatile Cl4-5DD/Fs, however, are true "multimedia" compounds, with their estimated atmospheric sink being roughly as important as the terrestrial sink (in the case of Cl5DD/Fs) or outweighing it (e.g., Cl4DD/Fs).

Lohmann, Rainer; Jurado, Elena; Dachs, Jordi; Lohmann, Ulrike; Jones, Kevin C.

2006-11-01

386

Brine flow in heated geologic salt.  

SciTech Connect

This report is a summary of the physical processes, primary governing equations, solution approaches, and historic testing related to brine migration in geologic salt. Although most information presented in this report is not new, we synthesize a large amount of material scattered across dozens of laboratory reports, journal papers, conference proceedings, and textbooks. We present a mathematical description of the governing brine flow mechanisms in geologic salt. We outline the general coupled thermal, multi-phase hydrologic, and mechanical processes. We derive these processes' governing equations, which can be used to predict brine flow. These equations are valid under a wide variety of conditions applicable to radioactive waste disposal in rooms and boreholes excavated into geologic salt.

Kuhlman, Kristopher L.; Malama, Bwalya

2013-03-01

387

Importance of the Inverted Control in Measuring Holistic Face Processing with the Composite Effect and Part-Whole Effect  

PubMed Central

Holistic coding for faces is shown in several illusions that demonstrate integration of the percept across the entire face. The illusions occur upright but, crucially, not inverted. Converting the illusions into experimental tasks that measure their strength – and thus index degree of holistic coding – is often considered straightforward yet in fact relies on a hidden assumption, namely that there is no contribution to the experimental measure from secondary cognitive factors. For the composite effect, a relevant secondary factor is size of the “spotlight” of visuospatial attention. The composite task assumes this spotlight can be easily restricted to the target half (e.g., top-half) of the compound face stimulus. Yet, if this assumption were not true then a large spotlight, in the absence of holistic perception, could produce a false composite effect, present even for inverted faces and contributing partially to the score for upright faces. We review evidence that various factors can influence spotlight size: race/culture (Asians often prefer a more global distribution of attention than Caucasians); sex (females can be more global); appearance of the join or gap between face halves; and location of the eyes, which typically attract attention. Results from five experiments then show inverted faces can sometimes produce large false composite effects, and imply that whether this happens or not depends on complex interactions between causal factors. We also report, for both identity and expression, that only top-half face targets (containing eyes) produce valid composite measures. A sixth experiment demonstrates an example of a false inverted part-whole effect, where encoding-specificity is the secondary cognitive factor. We conclude the inverted face control should be tested in all composite and part-whole studies, and an effect for upright faces should be interpreted as a pure measure of holistic processing only when the experimental design produces no effect inverted. PMID:23382725

McKone, Elinor; Davies, Anne Aimola; Darke, Hayley; Crookes, Kate; Wickramariyaratne, Tushara; Zappia, Stephanie; Fiorentini, Chiara; Favelle, Simone; Broughton, Mary; Fernando, Dinusha

2013-01-01

388

Radionuclide migration in clayrock host formations for deep geological disposal of radioactive waste: advances in process understanding and up-scaling methods resulting from the EC integrated project `Funmig  

NASA Astrophysics Data System (ADS)

One of the ‘pillars' supporting Safety Cases for deep geological disposal of radioactive waste in clayrock formations is the knowledge base regarding radionuclide (Rn) retention by sorption and diffusion-driven transport which is why the EC integrated project ‘Funmig' focused a major part of its effort on advancing understanding of these two macroscopic phenomena. This talk presents some of the main results of this four year effort (2005-2008). One of the keys to understanding diffusion-driven transport of anionic and cationic radionuclide species in clayrocks lies in a detailed understanding of the phenomena governing Rn total concentration and speciation (dissolved, adsorbed) in the different types of pore spaces present in highly-compacted masses of permanently charged clay minerals. Work carried out on a specifically synthesized montmorillonite (a model for the clay mineral fraction in clayrocks) led to development, and preliminary experimental validation, of a conceptually coherent set of theoretical models (molecular dynamics, electrostatic double layer, thermodynamic) describing dissolved ion and water solvent behavior in this material. This work, complemented by the existing state of the art, provides a sound theoretical basis for explaining such important phenomena as anion exclusion, cation exchange and the diffusion behavior of anions, weakly sorbing cations and water tracers. Concerning the behavior of strongly sorbing and/or redox-reactive radionuclides in clay systems, project research improved understanding of the nature of sorption reactions and sorbed species structure for key radioelements, or analogues (U, Se, Eu, Sm, Yb, Nd) on the basal surfaces and in the interlayers of synthetic or purified clay minerals. A probable mechanism for Se(IV) retention by reduction to Se° in Fe2+-containing clays was brought to light; this same process was also studied on the Callovo-Oxfordien clayrock targeted by the French radwaste management program. The migration of most radionuclides in clayrocks, in particular the actinides, is limited by their strong sorption on rock mineral surfaces. Much effort was devoted in Funmig to improving understanding of this process on the clayrocks being studied in the Swiss, Belgian and French radwaste management programs. Specific attention was focused on (i) elucidating the effect of dissolved organic matter on Am(III), Th(IV), Eu(III) sorption on clayrock surfaces and (ii) determining the link between Kd measured on dispersed rock systems and the Kd operant in intact rock volumes, i.e. during diffusion. Regarding the latter question, results indicate that Kd values for ‘dispersed' and ‘intact' materials are quite similar for certain elements (Na, Sr, Cs, Co). On the other hand, Kd values obtained by modeling results of diffusion experiments involving strongly sorbing elements as Cs, Co and Eu were always significantly smaller than those predicted based on sorption data measured in corresponding batch systems. This is an area where additional research is being planned. A major effort was devoted to improving understanding of the effects of small-scale (?m to cm) clayrock structure and large-scale (dm to hm) mineralogical composition on radionuclide diffusion-retention. The program focusing on the small-scale produced a method for simulating the results of tracer diffusion in an intact rock based on the actual rock microstructure of the rock sample to be used in the diffusion experiment. This model was used to predict / inverse model the spatial distribution of highly sorbing tracers (Eu, Cu). This overall approach is also being used to understand how changes in mineralogical composition can affect the values of macroscopic diffusion parameters (De, tortuosity, anisiotropy). At a much larger scale, the results of (i) a geostatistical analysis of clayrock mineralogical variability and (ii) measurements of De and Kd dependence on mineralogy for Cs and Cl, were combined to create models of parameter variability at the formation scale. These models were used to evaluate t

Altmann, S.; Tournassat, C.; Goutelard, F.; Parneix, J. C.; Gimmi, T.; Maes, N.

2009-04-01

389

Assessing the relative importance of local and regional processes on the survival of a threatened salmon population.  

PubMed

Research on regulatory mechanisms in biological populations often focuses on environmental covariates. An integrated approach that combines environmental indices with organismal-level information can provide additional insight on regulatory mechanisms. Survival of spring/summer Snake River Chinook salmon (Oncorhynchus tshawytscha) is consistently low whereas some adjacent populations with similar life histories experience greater survival. It is not known if populations with differential survival respond similarly during early marine residence, a critical period in the life history. Ocean collections, genetic stock identification, and otolith analyses were combined to evaluate the growth-mortality and match-mismatch hypotheses during early marine residence of spring/summer Snake River Chinook salmon. Interannual variation in juvenile attributes, including size at marine entry and marine growth rate, was compared with estimates of survival and physical and biological metrics. Multiple linear regression and multi-model inference were used to evaluate the relative importance of biological and physical metrics in explaining interannual variation in survival. There was relatively weak support for the match-mismatch hypothesis and stronger evidence for the growth-mortality hypothesis. Marine growth and size at capture were strongly, positively related to survival, a finding similar to spring Chinook salmon from the Mid-Upper Columbia River. In hindcast models, basin-scale indices (Pacific Decadal Oscillation (PDO) and the North Pacific Gyre Oscillation (NPGO)) and biological indices (juvenile salmon catch-per-unit-effort (CPUE) and a copepod community index (CCI)) accounted for substantial and similar portions of variation in survival for juvenile emigration years 1998-2008 (R2>0.70). However, in forecast models for emigration years 2009-2011, there was an increasing discrepancy between predictions based on the PDO (50-448% of observed value) compared with those based on the NPGO (68-212%) or biological indices (CPUE and CCI: 83-172%). Overall, the PDO index was remarkably informative in earlier years but other basin-scale and biological indices provided more accurate indications of survival in recent years. PMID:24924741

Miller, Jessica A; Teel, David J; Peterson, William T; Baptista, Antonio M

2014-01-01

390

Digital geological mapping with tablet PC and PDA: A comparison  

NASA Astrophysics Data System (ADS)

Both the hardware and software available for digital geological mapping (DGM) have advanced considerably in recent years. Mobile computers have become cheaper, lighter, faster and more power efficient. Global Positioning Systems (GPS) have become cheaper, smaller and more accurate, and software specifically designed for geological mapping has become available. These advances have now reached a stage where it is effective to replace traditional paper-based mapping techniques with those employing DGM methodologies. This paper attempts to assess and evaluate two currently available DGM systems for geological outcrop mapping: one based on a Personal Digital Assistant (PDA) running ESRI "ArcPad", and the second based on a Tablet PC running "Map IT" software. Evaluation was based on field assessment during mapping of a well-exposed coastal section of deformed Carboniferous and Permian rocks at N. Tynemouth in NE England. Prior to the field assessment, several key criteria were identified as essential attributes of an effective DGM system. These criteria were used as the basis for the assessment and evaluation process. Our findings suggest that the main concerns presented by sceptics opposed to DGM have largely been resolved. In general, DGM systems using a Tablet PC were found to be most suitable for a wide range of geological data collection tasks, including detailed outcrop mapping. In contrast, systems based on a PDA, due to small screen and limited processing power, were best suited for more basic mapping and simple data collection tasks. In addition, PDA-based systems can be particularly advantageous for mapping projects in remote regions, in situations where there is a limited power supply or where total weight of equipment is an important consideration.

Clegg, P.; Bruciatelli, L.; Domingos, F.; Jones, R. R.; De Donatis, M.; Wilson, R. W.

2006-12-01

391

Regional geology subprogram: Geological interpretation of ERTS imagery of the occidental region of Bolivia  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Using ERTS-1 imagery, it is possible to delimit great lithological units, folds, lineaments, faults, and in lesser degree unconformities. In the morphological aspect, the images show clearly the relief necessary for geological interpretation. The ERTS-1 images are important for the preparation of the geological and tectonic map of Bolivia, on a 1:1 million scale, if conventional methods of work are used as a base.

Brockmann, C. E. (principal investigator); Ayllon, R. B.

1973-01-01

392

B.S. GEOLOGY (Geology Subplan) CHECKLIST of required courses for major Geology Core Courses: 9-10 courses, 33-34 credits  

E-print Network

531 ­ Tectonics 555 ­ Dynamic Digital Maps 557 ­ Coastal Processes 563 ­ Glacial Geology 567 ­ Planetary Geology 571 ­ General Geophysics 575 ­ Paleomagnetism 587 ­ Hydrogeology 591D ­ Spatial Data Geochemistry 615 ­ Organic and Biogeochemistry 627 ­ Clay Petrology 687 ­ Advanced Hydrogeology 691C ­ Optical

Massachusetts at Amherst, University of

393

Impact, and its implications for geology  

NASA Astrophysics Data System (ADS)

The publication of seminal texts on geology and on meteoritics in the 1790s, laid the groundwork for the emergence of each discipline as a modern branch of science. Within the past three decades, impact cratering has become universally accepted as a process that sculptures the surfaces of planets and satellites throughout the solar system. Nevertheless, one finds in-depth discussions of impact processes mainly in books on the Moon or in surveys of the Solar System. The historical source of the separation between meteoritics and geology is easy to identify. It began with Hutton. Meteorite impact is an extraordinary event acting instantaneously from outside the Earth. It violates Hutton's principles, which were enlarged upon and firmly established as fundamental to the geological sciences by Lyell. The split between meteoritics and geology surely would have healed as early as 1892 if the investigations conducted by Gilbert (1843-1918) at the crater in northern Arizona had yielded convincing evidence of meteorite impact. The 1950s and 1960s saw a burgeoning of interest in impact processes. The same period witnessed the so-called revolution in the Earth Sciences, when geologists yielded up the idea of fixed continents and began to view the Earth's lithosphere as a dynamic array of horizontally moving plates. Plate tectonics, however, is fully consistent with the geological concepts inherited from Hutton: the plates slowly split, slide, and suture, driven by forces intrinsic to the globe.

Marvin, Ursula B.

394

Impact, and its implications for geology  

NASA Technical Reports Server (NTRS)

The publication of seminal texts on geology and on meteoritics in the 1790s, laid the groundwork for the emergence of each discipline as a modern branch of science. Within the past three decades, impact cratering has become universally accepted as a process that sculptures the surfaces of planets and satellites throughout the solar system. Nevertheless, one finds in-depth discussions of impact processes mainly in books on the Moon or in surveys of the Solar System. The historical source of the separation between meteoritics and geology is easy to identify. It began with Hutton. Meteorite impact is an extraordinary event acting instantaneously from outside the Earth. It violates Hutton's principles, which were enlarged upon and firmly established as fundamental to the geological sciences by Lyell. The split between meteoritics and geology surely would have healed as early as 1892 if the investigations conducted by Gilbert (1843-1918) at the crater in northern Arizona had yielded convincing evidence of meteorite impact. The 1950s and 1960s saw a burgeoning of interest in impact processes. The same period witnessed the so-called revolution in the Earth Sciences, when geologists yielded up the idea of fixed continents and began to view the Earth's lithosphere as a dynamic array of horizontally moving plates. Plate tectonics, however, is fully consistent with the geological concepts inherited from Hutton: the plates slowly split, slide, and suture, driven by forces intrinsic to the globe.

Marvin, Ursula B.

1988-01-01

395

Geoscape Vancouver: Living with our Geological Landscape  

NSDL National Science Digital Library

This site is about the geology and dynamic landscape of the Vancouver, British Columbia area. The people of Vancouver live where the Fraser River breaches the coastal mountains to reach the inland sea of the Strait of Georgia. This landscape is underlain by a variety of earth materials and is continually shaped by earth processes - a geological landscape or geoscape. The processes include colliding crustal plates and mountain-building, earthquakes, volcanic eruptions, landslides, and the work of water, and past glaciers. References are given to printed and web resources for additional information.

396

Geology By Lightplane  

NSDL National Science Digital Library

In 1966, Professor Louis J. Maher of the University of Wisconsin-Madison's Department of Geology and Geophysics piloted a department-owned Cessna over the continental US taking photos for use in his geology courses. As Maher flew, his trusty co-pilot and graduate assistant, Charles Mansfield, snapped the photos. The resulting collection is an assortment of breathtaking images of classic geological features, now available online for noncommercial use by educators (download via FTP). Maher gives us birds-eye views of structural features in Wyoming's Wind River Range, sedimentary strata in Arches National Park and the Grand Canyon, glacial landscapes in Northern Minnesota, and ancient lava flows in Arizona, to name just a few.

Maher, Louis J.

2001-01-01

397

Sedimentology and petroleum geology  

SciTech Connect

In this introduction to sedimentology and petroleum geology the subjects, which are closely related but mostly treated separately, are integrated. The first part covers the basic aspects of sedimentology, sedimentary geochemistry and diagenesis, including brief discussions of flow in rivers and channels, types of sediment transport, lake and river deposits, deltas (river-dominated, tide-dominated, and wave-dominated) and the water budget. Principles of stratigraphy, seismic stratigraphy and basin modeling form the basis for the last part on petroleum geology. Here subjects include the composition of kerogen and hydrocarbons, theories of migration and trapping of hydrocarbons and properties of reservoir rocks. Finally, short introductions to well logging and production geology are given.

Bjorlykke, K.

1989-01-01

398

Global sedimentary geology program  

SciTech Connect

The Society of Economic Paleontologists and Mineralogists, in collaboration with the International Association of Sedimentologists and the International Union of Geological Sciences Committee on Sedimentology, is developing a new international study under the provisional title of Global Sedimentary Geology Program (GSGP). Initially, three research themes are being considered: (1) event stratigraphy-the documentation of examples of mass extinctions, eustatic fluctuations in sea level, major episodes of volcanisms, and changes in ocean composition; (2) facies models in time and space-an expansion of the existing data base of examples of facies models (e.G., deltas, fluvial deposits, and submarine fans) and global-scale study of the persistence of facies at various times in geologic history; and (3) sedimentary indices of paleogeography and tectonics-the use of depositional facies and faunas in paleogeography and in assessing the timing, locus, and characteristics of tectonism. Plans are being developed to organize pilot projects in each of these themes.

Ginsburg, R.N.; Clifton, H.E.; Weimer, R.J.

1986-07-01

399

Structural Geology Resources  

NSDL National Science Digital Library

The Cutting Edge group at Carleton College has created a number of fine teaching resources for college-level instructors working across the geological sciences, and this website is no exception. This particular area of their larger site is primarily intended for educators who teach structural geology. As visitors scroll through the site, they will find thematic areas that include links to computer applications, geologic maps that can be used for instructional purposes, and specific classroom activities. Some of these activities include "Using Field Lab Write-ups to Develop Observational and Critical Thinking Skills" and "Analysis of Sidewalk Fractures". Additionally, visitors can sign up for their listserv discussions and view presentations from different workshops they have conducted in the past.

400

Alaskan North Slope Geology  

NASA Astrophysics Data System (ADS)

The discovery well for the Prudhoe Bay field, the largest oil accumulatn yet found in the United States, was drilled on the Arctic coast of Alaska by ARCO and Exxon in 1968. A decade of exploratory geology and increasingly detailed geophysical surveys, mostly by Sinclair and British Petroleum in the early years, but then by a number of companies, preceded the discovery. Systematic U.S. Geological Survey (USGS) reconnaissance of the Brooks Range—the great mountain system of northern Alaska—had begun in the 1940s and was accelerated after the discovery, as was industry work. In the last decade, scientists from the Alaska Division of Geology and Geophysics and from various universities have become increasingly involved. This modestly priced two-volume work presents hitherto unavailable summaries of much of this modern work.

Hamilton, Warren

401

Understanding Geological Time  

NSDL National Science Digital Library

In this classroom activity, middle school students gain an understanding of geologic time. The activity opens with background information for teachers about carbon and radiometric dating. In a classroom discussion, students share what they know about geologic time. Then, working in small groups responsible for different eras, students create a timeline for their assigned era by conducting library and Internet research. The activity concludes by having students review all the timelines to compare how long humans have been on the Earth to the length of time dinosaurs inhabited the planet.

402

Principles of isotope geology  

Microsoft Academic Search

Discussions of methods of isotope dating using Rb-Sr, K-Ar, ⁴°Ar\\/³⁹Ar, Re-Os, Lu-Hf, K-Ca, U, Tb-Pb, ¹⁴C, common lead, S,O,H, fission track, and U-series disequilibrium are included in respective chapters. Introductory chapters discussing the basics of isotope geology, atomic structure, decay mechanisms and mass spectrometry are included along with two appendices; the geological time scale for the Phanerzoic and a fitting

G Faure

1977-01-01

403

The Evolution of Dinosaurs Over Geologic Time  

NSDL National Science Digital Library

This lesson plan asks high school students to combine their knowledge of evolution, geologic time, and dinosaurs into a discussion of how these three topics overlap with regard to dinosaur evolution in the Cretaceous period. Students will read about the work of paleontologist Paul Sereno and list the dinosaurs he has discovered as well as the locations in which they were found and the time periods in which they lived; review the periods of geologic time; review the theory of evolution and write a paragraph explaining how geographic isolation would contribute to the evolutionary process; write paragraphs describing the changes to the continental layout of the Earth during the Cretaceous period; write paragraphs relating geological changes to dinosaur evolution during the Cretaceous period; and create posters or computer presentations illustrating the Earth during the Cretaceous period and the evolution processes of dinosaur species during this time.

404

OneGeology-Europe Plus Initiative  

NASA Astrophysics Data System (ADS)

The Geological Surveys of the European countries hold valuable resources of geological data but, to discover, understand and use this data efficiently, a good level of standardization is essential. The OneGeology-Europe project had the aim of making geological maps at a scale 1:1M from Europe discoverable and accessible, available under a common data license and described by multilingual metainformation. A harmonized specification for basic geological map data was developed so that significant progress towards harmonizing the datasets was achieved. Responsibility for the management of the OneGeology-Europe portal has been taken by EuroGeoSurveys and provided by CGS and BRGM. Of the 34 members of EuroGeoSurveys (EGS), only 20 participated in the OneGeology-Europe project (Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Ireland, Italy, Luxembourg, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Sweden, Spain, United Kingdom), so the European area was not completely covered. At the 33rd General Meeting and Directors Workshop in 2012 it was therefore decided to establish a successor initiative OneGeology Europe Plus (1G-E+) with the purpose of extending the coverage by geological maps at a scale of 1:1 M to all the EGS member countries (including Albania, Austria, Bulgaria, Croatia, Cyprus, Greece, Iceland, Lithuania, Malta, Romania, Russia, Switzerland, Turkey, Ukraine) and also, if possible, to the other European countries (Belorussia, Bosnia and Herzegovina, Faeroe Islands, Kosovo, Latvia, Macedonia, Moldavia, Montenegro, Serbia). In order to achieve the desired result, it has been necessary for the new GSOs who intend to supply the additional 1G-E standardized services to carry out the work using their own staff and resources. The technical guidance and other support have been provided by the 1G-E+ Technical Support Team, funded from the internal budgets of their respective surveys. The team is coordinated by the Czech Geological Survey (CGS) working with the Bureau de Recherches Géologiques et Minières (BRGM), the British Geological Survey (BGS), the Geological Survey of Denmark and Greenland (GEUS) and the Geological Survey of Slovenia (GeoZS). The Geological Survey of the Netherlands (TNO) decided to provide financial support for the initiative. The Technical Support Team has been providing the technical advice required to enable the inclusion of geological maps from new countries in the 1G-E Portal using the standards developed and accepted for 1G-E. Cookbooks, on-line help and a helpdesk are provided during the work. A technical workshop was organized at which all the technical steps required to reach the target solution were presented and discussed. All newcomers must agree the existing common license that was created for downloading the 1G-E data. It should be emphasized that the results will be displayed as part of the 1G-E project and metadata/portal infrastructures. The process is still ongoing because the harmonization work for most of the countries involved has been a demanding process. Some countries are facing difficulties because of the lack of expert personnel or insufficient resources of data. Despite some problems, the 1G-E+ initiative and the work involved has contributed to effective networking and technical cooperation between the GSOs across the wider European region.

Capova, Dana; Kondrova, Lucie

2014-05-01

405

Track of the Yellowstone hotspot: Young and ongoing geologic processes from the Snake River Plain to the Yellowstone Plateau and Tetons  

Microsoft Academic Search

This fi eld trip highlights various stages in the evolution of the Snake River Plain- Yellowstone Plateau bimodal volcanic province, and associated faulting and uplift, also known as the track of the Yellowstone hotspot. The 16 Ma Yellowstone hotspot track is one of the few places on Earth where time-transgressive processes on conti- nental crust can be observed in the

L. A. Morgan; K. L. Pierce; W. C. Pat Shanks

406

Quaternary Geologic Map of Connecticut and Long Island Sound Basin  

USGS Publications Warehouse

The Quaternary geologic map (sheet 1) and explanatory figures and cross sections (sheet 2) portray the geologic features formed in Connecticut during the Quaternary Period, which includes the Pleistocene (glacial) and Holocene (postglacial) Epochs. The Quaternary Period has been a time of development of many details of the landscape and of all the surficial deposits. At least twice in the late Pleistocene, continental ice sheets swept across Connecticut. Their effects are of pervasive importance to the present occupants of the land. The Quaternary geologic map illustrates the geologic history and the distribution of depositional environments during the emplacement of glacial and postglacial surficial deposits and the landforms resulting from those ev