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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

Geological processes and evolution  

USGS Publications Warehouse

Geological mapping and establishment of stratigraphic relationships provides an overview of geological processes operating on Mars and how they have varied in time and space. Impact craters and basins shaped the crust in earliest history and as their importance declined, evidence of extensive regional volcanism emerged during the Late Noachian. Regional volcanism characterized the Early Hesperian and subsequent to that time, volcanism was largely centered at Tharsis and Elysium, continuing until the recent geological past. The Tharsis region appears to have been largely constructed by the Late Noachian, and represents a series of tectonic and volcanic centers. Globally distributed structural features representing contraction characterize the middle Hesperian. Water-related processes involve the formation of valley networks in the Late Noachian and into the Hesperian, an ice sheet at the south pole in the middle Hesperian, and outflow channels and possible standing bodies of water in the northern lowlands in the Late Hesperian and into the Amazonian. A significant part of the present water budget occurs in the present geologically young polar layered terrains. In order to establish more firmly rates of processes, we stress the need to improve the calibration of the absolute timescale, which today is based on crater count systems with substantial uncertainties, along with a sampling of rocks of unknown provenance. Sample return from carefully chosen stratigraphic units could calibrate the existing timescale and vastly improve our knowledge of Martian evolution.

Head, J. W.; Greeley, R.; Golombek, M. P.; Hartmann, W. K.; Hauber, E.; Jaumann, R.; Masson, P.; Neukum, G.; Nyquist, L. E.; Carr, M. H.

2001-01-01

3

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

4

Coastal Processes and Offshore Geology  

Microsoft Academic Search

The modern coastal geology of Virginia results from the interactions of modern processes, primarily waves, tidal currents and sea-level rise, with the antecedent geology. The ancient and major rivers draining the Piedmont and interior highlands of eastern North America carried sediments that were deposited in various areas across the physiographic continuum of the coastal plain and continental shelf as sea

Carl H. Hobbs; David E. Krantz; Geoffrey L. Wikel

5

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

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.

7

Prediction of Exogenic Geological Processes  

Microsoft Academic Search

Prediction of exogenic geological processes (EGP) involves scientifically substantiated forecasting of events in space and\\u000a time under the action of natural and anthropogenically induced factors. The goal of the EGP prediction is to give the answers\\u000a to the three basic questions — where, when and of which activity (size) one or another type of exogenic geological process\\u000a can happen, and

Arkady Sheko; Vladimir Krupoderov

8

Deterministic geologic processes and stochastic modeling  

SciTech Connect

Recent outcrop sampling at Yucca Mountain, Nevada, has produced significant new information regarding the distribution of physical properties at the site of a potential high-level nuclear waste repository. Consideration of the spatial distribution of measured values and geostatistical measures of spatial variability indicates that there are a number of widespread deterministic geologic features at the site that have important implications for numerical modeling of such performance aspects as ground water flow and radionuclide transport. These deterministic features have their origin in the complex, yet logical, interplay of a number of deterministic geologic processes, including magmatic evolution; volcanic eruption, transport, and emplacement; post-emplacement cooling and alteration; and late-stage (diagenetic) alteration. Because of geologic processes responsible for formation of Yucca Mountain are relatively well understood and operate on a more-or-less regional scale, understanding of these processes can be used in modeling the physical properties and performance of the site. Information reflecting these deterministic geologic processes may be incorporated into the modeling program explicitly, using geostatistical concepts such as soft information, or implicitly, through the adoption of a particular approach to modeling. It is unlikely that any single representation of physical properties at the site will be suitable for all modeling purposes. Instead, the same underlying physical reality will need to be described many times, each in a manner conducive to assessing specific performance issues.

Rautman, C.A. [Sandia National Labs., Albuquerque, NM (United States); Flint, A.L. [Geological Survey, Mercury, NV (United States)

1991-12-31

9

Deterministic geologic processes and stochastic modeling  

Microsoft Academic Search

Recent outcrop sampling at Yucca Mountain, Nevada, has produced significant new information regarding the distribution of physical properties at the site of a potential high-level nuclear waste repository. Consideration of the spatial distribution of measured values and geostatistical measures of spatial variability indicates that there are a number of widespread deterministic geologic features at the site that have important implications

C. A. Rautman; A. L. Flint

1991-01-01

10

Geologic processes influence the effects of mining on aquatic ecosystems  

USGS Publications Warehouse

Geologic processes strongly influence water and sediment quality in aquatic ecosystems but rarely are geologic principles incorporated into routine biomonitoring studies. We test if elevated concentrations of metals in water and sediment are restricted to streams downstream of mines or areas that may discharge mine wastes. We surveyed 198 catchments classified as “historically mined” or “unmined,” and based on mineral-deposit criteria, to determine whether water and sediment quality were influenced by naturally occurring mineralized rock, by historical mining, or by a combination of both. By accounting for different geologic sources of metals to the environment, we were able to distinguish aquatic ecosystems limited by metals derived from natural processes from those due to mining. Elevated concentrations of metals in water and sediment were not restricted to mined catchments; depauperate aquatic communities were found in unmined catchments. The type and intensity of hydrothermal alteration and the mineral deposit type were important determinants of water and sediment quality as well as the aquatic community in both mined and unmined catchments. This study distinguished the effects of different rock types and geologic sources of metals on ecosystems by incorporating basic geologic processes into reference and baseline site selection, resulting in a refined assessment. Our results indicate that biomonitoring studies should account for natural sources of metals in some geologic environments as contributors to the effect of mines on aquatic ecosystems, recognizing that in mining-impacted drainages there may have been high pre-mining background metal concentrations.

Schmidt, Travis S.; Clements, William H.; Wanty, Richard B.; Verplanck, Philip L.; Church, Stanley E.; San Juan, Carma A.; Fey, David L.; Rockwell, Barnaby W.; DeWitt, Ed H.; Klein, Terry L.

2012-01-01

11

The importance of geobotany in geological remote sensing applications  

NASA Technical Reports Server (NTRS)

A description of the different effects of variations in ground cover vegetation on remote sensing data in geological and prospecting applications is presented. The different variations are divided into three categories: structural; taxonomic and spectral. Structural variations include changes in the physical appearance of ground cover which may be detectable by a remote sensing instrument. Taxonomic variations occur in those plant communities which are associated with specific geological regions. Spectral variations are due to specific geochemical stresses which may be useful in characterizing geological features at a site. The need for a general scheme for the interpretation of geobotanical remote sensing data is discussed: Geosat data for the field reflectance spectra of different tree species in West Virginia are presented as examples.

Mouat, D. A.; Collins, W.; Elvidge, C.; Lyon, R. J. P.; Labovitz, M. L.; Milton, N. M.; Parrish, J.; Rock, B. N.; Wickland, D. E.; Arp, G. K.

1983-01-01

12

Investigation of the Structure of Geological Process through Multivariate Statistical Analysis—The Creation of a Coal  

Microsoft Academic Search

The purpose of this study was to capture the structure of a geological process within a multivariate statistical framework\\u000a by using geological data generated by that process and, where applicable, by associated processes. It is important to the\\u000a practitioners of statistical analysis in geology to determine the degree to which the geological process can be captured and\\u000a explained by multivariate

Lawrence J. Drew; Eric C. Grunsky; John H. Schuenemeyer

2008-01-01

13

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

14

Geologic process studies using Synthetic Aperture Radar (SAR) data  

NASA Technical Reports Server (NTRS)

The use of SAR data to study geologic processes for better understanding of recent tectonic activity and climate change as well as the mitigation of geologic hazards and exploration for nonrenewable resources is discussed. The geologic processes that are particularly amenable to SAR-based data include volcanism; soil erosion, degradation, and redistribution; coastal erosion and inundation; glacier fluctuations; permafrost; and crustal motions. When SAR data are combined with data from other planned spaceborne sensors including ESA ERS, the Japanese Earth Resources Satellite, and the Canadian Radarsat, it will be possible to build a time-series view of temporal changes over many regions of earth.

Evans, Diane L.

1992-01-01

15

The nuclear microprobe as a probe of earth structure and geological processes  

NASA Astrophysics Data System (ADS)

The nuclear microprobe is ideally suited to the microanalysis of geological samples where trace element quantitative microanalysis and imaging are essential. The use of these methods, particularly proton-induced X-ray emission (PIXE), is becoming more common in many areas of geology as the impact of trace element data become more widely appreciated. This review provides an update on the progress of geological applications of the nuclear microprobe since these were reviewed at the previous conference on Nuclear Microprobe Technology and Applications in 1992. But more importantly, the applications described in more detail in this paper are chosen to illustrate the impact nuclear microprobe methods are having on our understanding of earth structure and geological processes, and to focus attention on the power and potential of quantitative nuclear microprobe methods for further geological research.

Ryan, C. G.

1995-09-01

16

Exogenic Geological Processes As a Landform-Shaping Factor  

Microsoft Academic Search

Exogenic processes include geological phenomena and processes that originate externally to the Earth’s surface. They are genetically\\u000a related to the atmosphere, hydrosphere and biosphere, and therefore to processes of weathering, erosion, transportation, deposition,\\u000a denudation etc. Exogenic factors and processes could also have sources outside the Earth, for instance under the influence\\u000a of the Sun, Moon etc. The above mentioned processes

Marek Graniczny

17

Process for license application development for the geologic repository  

SciTech Connect

The Department of Energy (DOE), specifically the Office of Civilian Radioactive Waste Management (OCRWM) has been charged by the US Congress, through the Nuclear Waste Policy Act (NWPA), with the responsibility for obtaining a license to develop a geologic repository. The NRC is the licensing authority for geologic disposal, and its regulations pertinent to construction authorization and license application are specified in 10 CFR Part 60, Disposal of High-Level Radioactive Wastes in Geologic Repositories, {section}60.21ff and {section}60.31ff. This paper discusses the process the Yucca Mountain Site Characterization Project (YMP) will use to identify and apply regulatory and industry guidance to development of the license application (LA) for a geologic repository at Yucca Mountain, Nevada. This guidance will be implemented by the Technical Guidance Document for Preparation of the License Application (TGD), currently in development.

Franks, D.M. [Duke Engineering and Services, Las Vegas, NV (United States); Henderson, N.C.

1998-06-01

18

Geological Disposal Concept Selection Aligned with a Voluntarism Process - 13538  

SciTech Connect

The UK's Radioactive Waste Management Directorate (RWMD) is currently at a generic stage in its implementation programme. The UK site selection process is a voluntarist process and, as yet, no communities have decided to participate. RWMD has set out a process to describe how a geological disposal concept would be selected for the range of higher activity wastes in the UK inventory, including major steps and decision making points, aligned with the stages of the UK site selection process. A platform of information is being developed on geological disposal concepts at various stages of implementation internationally and, in order to build on international experience, RWMD is developing its approach to technology transfer. The UK has a range of different types of higher activity wastes with different characteristics; therefore a range of geological disposal concepts may be needed. In addition to identifying key aspects for considering the compatibility of different engineered barrier systems for different types of waste, RWMD is developing a methodology to determine minimum separation distances between disposal modules in a co-located geological disposal facility. RWMD's approach to geological disposal concept selection is intended to be flexible, recognising the long term nature of the project. RWMD is also committed to keeping alternative radioactive waste management options under review; an approach has been developed and periodic reviews of alternative options will be published. (authors)

Crockett, Glenda; King, Samantha [Nuclear Decommissioning Authority, Building 587, Curie Avenue, Harwell Oxford, Didcot, Oxfordshire, OX11 0RH (United Kingdom)] [Nuclear Decommissioning Authority, Building 587, Curie Avenue, Harwell Oxford, Didcot, Oxfordshire, OX11 0RH (United Kingdom)

2013-07-01

19

Geology and Surface Processes on Titan  

Microsoft Academic Search

The surface of Titan has been revealed globally, if incompletely, by Cassini observations at infrared and radar wavelengths as well as locally by the instruments on the Huygens probe. Extended dune fields, lakes, mountainous terrain, dendritic erosion patterns and erosional remnants indicate dynamic surface processes. Valleys, small-scale gullies and rounded cobbles such as those observed at the Huygens landing site

Ralf Jaumann; Randolph L. Kirk; Ralph D. Lorenz; Rosaly M. C. Lopes; Ellen Stofan; Elizabeth P. Turtle; Horst Uwe Keller; Charles A. Wood; Christophe Sotin; Laurence A. Soderblom; Martin G. Tomasko

2010-01-01

20

Teaching Introductory Geology by a Paradigm, Process and Product Approach  

NASA Astrophysics Data System (ADS)

Students in introductory geology courses can easily become lost in the minutiae of terms and seemingly random ideas and theories. One way to avoid this and provide a holistic picture of each major subject area in a beginning course is to introduce, at the start of each section, the ruling paradigm, the processes, and resultant products. By use of these three Ps: paradigm, processes, and products, students have a reasonably complete picture of the subject area. If they knew nothing more than this simple construct, they would have an excellent perspective of the subject area. This provides a jumping off point for the instructor to develop the details. The three Ps can make course construction much more straightforward and complete. Students benefit since they have a clearer idea of what the subject is about and its importance. Retention may be improved and carryover to advanced courses may be aided. For faculty, the use of these three P's makes organizing a course more straightforward. Additionally, the instructor benefits include: 1. The main points are clearly stated, thus avoiding the problem of not covering the essential concepts. 2. The course topics hold together, pedagogically. There is significant opportunity for continuity of thought. 3. An outline is developed that is easily analyzed for holes or omissions. 4. A course emerges with a balance of topics, permitting appropriate time to be devoted to significant subject matter. 5. If a course is shared between faculty or passes from one faculty to another by semester or quarter, there is greater assurance that topics and concepts everyone agrees on can be adequately covered. 6. There is less guesswork involved in planning a course. New faculty have an approach that will make sense and allow them to feel less awash and more focused. In summary, taking time to construct a course utilizing the important paradigms, processes, and products can provide significant benefits to the instructor and the student. Material can be presented in a more coherent manner and allow students the opportunity to grasp essential concepts from the very beginning. There are fewer potential surprises and greater likelihood that key ideas can be retained, as opposed to retaining isolated fragments of information. Illustrations from over a decade of use in an introductory Physical and Historical Geology course will be presented.

Reams, M.

2008-12-01

21

The importance of subsurface geology for water source and vegetation communities in Cherokee Marsh, Wisconsin  

USGS Publications Warehouse

Restoration of disturbed wetland systems is an important component of wetland mitigation, yet uncertainty remains about how hydrologic processes affect biologic processes and wetlands patterns. To design more effective restoration strategies and re-establish native plant communities in disturbed wetlands, it is imperative to understand undisturbed systems. A site within Cherokee Marsh located in Madison, Wisconsin, USA, contains a relatively undisturbed area of wetland consisting of plant communities common within the prairie landscape including a fen, sedge meadow, and shallow marsh. These distinct communities are found within an area of minimal topographic relief, yet transitions from one community to the next occur over short distances. This study sought to characterize the geologic, hydrologic, and chemical gradients associated with these shifts in vegetation to gain insight into the factors controlling the spatial differences in dominant plant species, which could be critical for restoration success. Vegetation analyses revealed a transition of dominant sedge species, which appeared to correspond to changes in hydrology from a ground-water dominated to a surface-water dominated system (as determined by water isotopes). Along the same vegetation transect, subsurface coring results show a heterogeneous composition of peat and till with lateral and vertical variations in stratigraphy, which relates to variability in ground-water discharge as evidenced by hydroperiods and stable isotope composition. Applications of this type of approach throughout the glaciated terrains of the midwestern and northeastern United States and Canada can improve future wetland restoration and management. ?? 2007, The Society of Wetland Scientists.

Kurtz, A. M.; Bahr, J. M.; Carpenter, Q. J.; Hunt, R. J.

2007-01-01

22

Geologic Mapping, Volcanic Stages and Magmatic Processes in Hawaiian Volcanoes  

NASA Astrophysics Data System (ADS)

The concept of volcanic stages arose from geologic mapping of Hawaiian volcanoes. Subaerial Hawaiian lava successions can be divided generally into three constructional phases: an early (shield) stage dominated by thin-bedded basaltic lava flows commonly associated with a caldera; a later (postshield) stage with much thicker bedded, generally lighter colored lava flows commonly containing clinopyroxene; calderas are absent in this later stage. Following periods of quiescence of a half million years or more, some Hawaiian volcanoes have experienced renewed (rejuvenated) volcanism. Geological and petrographic relations irrespective of chemical composition led to the identification of mappable units on Niihau, Kauai, Oahu, Molokai, Maui and Hawaii, which form the basis for this 3-fold division of volcanic activity. Chemical data have complicated the picture. There is a growing tendency to assign volcanic stage based on lava chemistry, principally alkalicity, into tholeiitic shield, alkalic postshield, and silica undersaturated rejuvenation, despite the evidence for interbedded tholeiitic and alkalic basalts in many shield formations, and the presence of mildly tholeiitic lavas in some postshield and rejuvenation formations. A consistent characteristic of lava compositions from most postshield formations is evidence for post-melting evolution at moderately high pressures (3-7 kb). Thus, the mapped shield to postshield transitions primarily reflect the disappearance of shallow magma chambers (and associated calderas) in Hawaiian volcanoes, not the earlier (~100 ka earlier in Waianae Volcano) decline in partial melting that leads to the formation of alkalic parental magmas. Petrological signatures of high-pressure evolution are high-temperature crystallization of clinopyroxene and delayed crystallization of plagioclase, commonly to <3 % MgO. Petrologic modeling using pMELTS and MELTS algorithms allows for quantification of the melting and fractionation conditions giving rise to various Hawaiian lithologies. This analysis indicates that the important magmatic process that links geologic mapping to volcanic stage is thermal state of the volcano, as manifest by depth of magma evolution. The only criterion for rejuvenation volcanism is the presence of a significant time break (more than several hundred thousand years) preceding eruption.

Sinton, J. M.

2005-12-01

23

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

24

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

Microsoft Academic Search

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

R. L. Hunter; C. J. Mann

1989-01-01

25

Towards understanding how surface life can affect interior geological processes: a non-equilibrium thermodynamics approach  

Microsoft Academic Search

Life has significantly altered the Earth's atmosphere, oceans and crust. To what extent has it also affected interior geological processes? To address this question, three models of geological processes are formulated: mantle convection, continental crust uplift and erosion and oceanic crust recycling. These processes are characterised as non-equilibrium thermodynamic systems. Their states of disequilibrium are maintained by the power generated

J. G. Dyke; F. Gans; A. Kleidon

2011-01-01

26

Importance of geology to fisheries management: Examples from the northeastern Gulf of Mexico  

USGS Publications Warehouse

Seafloor mapping of shelf-edge habitats in the northeastern Gulf of Mexico demonstrates how sidescan-sonar imagery, seismic-reflection profiling, video data, geologic mapping, sediment sampling, and understanding the regional geologic history can enhance, support, and guide traditional fisheries research and management. New data from the Madison Swanson and Steamboat Lumps Marine Reserves reveal complex benthic habitats consisting of high-relief calcareous pinnacles, low-relief karstic hardbottom, rocky outcrops several kilometers in length, and variable thickness of fine-grained and apparently mobile coarse-grained sediments. Our data also show that certain fish alter the landscape by clearing sediment from hardbottom areas (e.g., red grouper Epinephelus morio) and by burrowing extensively in fine-grained sediment (e.g., tilefish Lopholatilus chamaeleonticeps). The seafloor imagery and geologic maps show that (a) sea level fluctuations played a dominant role in the development of the present-day regional geology, and (b) habitats (and benthic communities) are tied closely to geologic character. Understanding the geologic setting allowed for efficient and representative sampling of the biology. The geologic data can be used to set meaningful boundaries for fishery reserves and to help predict habitats in areas that are not well mapped. This interdisciplinary work added value to traditional research disciplines by providing management with integrated tools to make better decisions. ?? Copyright by the American Fisheries Society 2003.

Scanlon, K. M.; Koenig, C. C.; Coleman, F. C.; Miller, M.

2003-01-01

27

Impact craters: their importance in geologic record and implications for natural resource development  

SciTech Connect

Impacting bodies of sufficient size traveling at hypervelocities carry tremendous potential energy. This relatively infrequent process results in the instantaneous formation of unique structures that are characterized by extensive fracturing and brecciation of the target material. Impacts onto continental shield areas can create rich ore deposits, such as the Sudbury mining district in Canada. Impacts into the sedimentary column can instantaneously create hydrocarbon reservoirs out of initially nonporous rocks, such as at Red Wing Creek and Viewfield in the Williston basin. Associated reservoirs are usually limited to a highly deformed central uplift in larger craters, or to the fractured rim facies in smaller craters. The presence of reservoirs and trapping mechanisms is largely dependent, however, upon the preservation state of the crater in the subsurface. A catastrophic extraterrestrial event (a large asteroid impact) has also been suggested as the cause for the extinction of the dinosaurs, but the latest theory proposes a companion star with a 26 m.y. periodicity as the cause for numerous lifeform extinctions over a similar time interval. Regardless of their magnitude and distribution over the earth, it is clear that catastrophic extraterrestrial events have been responsible for altering the geologic column locally, regionally, and quite possibly on a global scale.

Levie, D. Jr.

1986-05-01

28

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

29

Some important fractional transformations for signal processing  

NASA Astrophysics Data System (ADS)

The fractional Fourier transform (FRT), that is useful mathematical and optical tool for signal processing, was defined as a generalization of the conventional Fourier transform. As opposed to the Fourier transform, the Hartley transform is a real (not complex) mathematical transformation and thus might be attractive for various applications. In optics, due to the fact that it is a real operation, it can be implemented with incoherent illumination. This paper suggests a generalization of the Hartley transformation based on the fractional Fourier transform. We coined it "fractional Hartley transform (FHT)". Possible optical implementation can be easily obtained optically. Since the definition is real, there is an additional significant for digital signal processing application where the fact that the transform is real decreases the computing complexity. Additional useful transformations used for signal processing are discussed as well.

Lohmann, Adolf W.; Mendlovic, David; Zalevsky, Zeev; Dorsch, Rainer G.

1996-02-01

30

Some important fractional transformations for signal processing  

Microsoft Academic Search

The fractional Fourier transform (FRT), that is useful mathematical and optical tool for signal processing, was defined as a generalization of the conventional Fourier transform. As opposed to the Fourier transform, the Hartley transform is a real (not complex) mathematical transformation and thus might be attractive for various applications. In optics, due to the fact that it is a real

Adolf W Lohmann; David Mendlovic; Zeev Zalevsky; Rainer G Dorsch

1996-01-01

31

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

32

Importance of quantum decoherence in brain processes  

NASA Astrophysics Data System (ADS)

Based on a calculation of neural decoherence rates, we argue that the degrees of freedom of the human brain that relate to cognitive processes should be thought of as a classical rather than quantum system, i.e., that there is nothing fundamentally wrong with the current classical approach to neural network simulations. We find that the decoherence time scales (~10-13-10-20 s) are typically much shorter than the relevant dynamical time scales (~10-3-10-1 s), both for regular neuron firing and for kinklike polarization excitations in microtubules. This conclusion disagrees with suggestions by Penrose and others that the brain acts as a quantum computer, and that quantum coherence is related to consciousness in a fundamental way.

Tegmark, Max

2000-04-01

33

Risk Assessment based on the Mathematical Model of Diffuse Exogenous Geological Processes  

Microsoft Academic Search

The estimation of the risk caused by hazardous geological processes is a common problem. The aim of this paper is to present\\u000a a method for solving problems involving a wide spectrum of diffuse exogenous geological processes, based on the mathematical\\u000a morphology of landscapes. Diffuse processes develop as random rounded sites within certain areas and include karstification,\\u000a subsidence, thermo-karstification and aeolian

Alexey Viktorov

2007-01-01

34

The lively Aysén fjord, Chile: Records of multiple geological processes  

NASA Astrophysics Data System (ADS)

The Aysén fjord is a 65 km long, east-west oriented fjord in Chilean Patagonia, located approximately at 45.4ºS and 73.2ºW, with a maximum water depth of 345 m. The fjord receives at present the riverine input of Aysén, Pescado, Condor and Cuervo rivers, which drain the surrounding up to 2000 m high Patagonian Andes. The fjord is crossed by a number of faults associated to the seismically active Liquiñe-Ofqui Fault Zone, a major trench parallel intra-arc fault system. After a four-month period of moderate seismicity, an Mw 6.2 earthquake on 21 April 2007 triggered dozens of subaerial landslides along the fjord flanks. Some of the landslides reached the fjord water mass, generating a series of tsunami-like displacement waves that impacted the adjacent coastlines with 3-12 m, locally over 50 m high run-ups, causing ten fatalities and severe damage to salmon farms. The research cruise DETSUFA on board BIO Hespérides in March 2013 mapped the submerged morphology of the fjord and gathered air-gun seismic profiles and sediment gravity cores in order to characterise the footprint of the landslides in the fjord floor. Very-high resolution multibeam bathymetry (4 m cell size) clearly shows the deformation structures created by the landslides in the inner fjord. The landslides descended and accelerated down the submerged fjord flanks, and reached the fjord floor at approx. 200 m water depth generating large, 1 to 10 m deep impact depressions. Sediment removed from these depressions moved radially and piled up in deformation rings formed by compressional ridges 10-15 m in height, block fields and a narrow frontal depression. Up to six >1.5 square km of these structures can be identified in the fjord. In addition, the DETSUFA survey extended beyond the SE-NW-oriented inner fjord past the Cuervo Ridge, located in front of the Cuervo river delta. The ridge, previously interpreted as a volcanic transverse structure, has most probably acted as a limit for grounding ice in the past, as suggested by the presence of melt-water channels lateral to the ridge. Beyond the ridge, the fjord smoothens and deepens to more than 330 m forming an enclosed basin before turning SW. There, it shallows back across a field of streamlined submerged hills of glacial origin. The external Aysén fjord, before joining to Canal Costa and Canal Moraleda, is characterized by three volcanic cones, one of them forming Isla Colorada - which also acted as a glacial limit - and the other two totally submerged and previously unknown. The largest one is 160 m high, 1.3 km in diameter and tops at 67 m water depth. This data set illustrates the complex interaction between fluvial, glacial, tectonic, volcanic and gravity processes and evidences the recent lively geological history of Aysén fjord.

Lastras, Galderic; Amblas, David; Calafat, Antoni; Canals, Miquel; Frigola, Jaime; Hermanns, Reginald L.; Lafuerza, Sara; Longva, Oddvar; Micallef, Aaron; Sepúlveda, Sergio A.; Vargas, Gabriel; Azpiroz, María; Bascuñán, Ignacio; Duhart, Paul; Iglesias, Olaia; Kempf, Philipp; Rayo, Xavier

2014-05-01

35

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

36

Active geologic processes in Barrow Canyon, northeast Chukchi Sea  

USGS Publications Warehouse

Circulation patterns on the shelf and at the shelf break appear to dominate the Barrow Canyon system. The canyon's shelf portion underlies and is maintained by the Alaska Coastal Current (A.C.C.), which flows northeastward along the coast toward the northeast corner of the broad Chukchi Sea. Offshelf and onshelf advective processes are indicated by oceanographic measurements of other workers. These advective processes may play an important role in the production of bedforms that are found near the canyon head as well as in processes of erosion or non-deposition in the deeper canyon itself. Coarse sediments recovered from the canyon axis at 400 to 570 m indicate that there is presently significant flow along the canyon. The canyon hooks left at a point north of Point Barrow where the A.C.C. loses its coastal constriction. The left hook, as well as preferential west-wall erosion, continues down to the abyssal plain of the Canada Basin at 3800 m. A possible explanation for the preferential west-wall erosion along the canyon, at least for the upper few hundred meters, is that the occasional upwelling events, which cause nutrient-rich water to flow along the west wall would in turn cause larger populations of burrowing organisms to live there than on the east wall, and that these organisms cause high rates of bioerosion. This hypothesis assumes that the dominant factor in the canyon's erosion is biological activity, not current velocity. Sedimentary bedforms consisting of waves and furrows are formed in soft mud in a region on the shelf west of the canyon head; their presence there perhaps reflects: (a) the supply of fine suspended sediments delivered by the A.C.C. from sources to the south, probably the Yukon and other rivers draining northwestern Alaska; and (b) the westward transport of these suspended sediments by the prevailing Beaufort Gyre which flows along the outer shelf. ?? 1982.

Eittreim, S.; Grantz, A.; Greenberg, J.

1982-01-01

37

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

Microsoft Academic Search

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

P. Stelling; S. Wuotila; M. Giuliani

2006-01-01

38

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

39

Engineering geological characteristics and processes of permafrost along the Qinghai–Xizang (Tibet) Highway  

Microsoft Academic Search

Engineering geological problems of thaw-settlement and frost-heave occur frequently along the Qinghai–Xizang (Tibet) Highway (QXH) line and produce an adverse impact on roadbed stability. Eight monitoring sites were established along the QXH to investigate the engineering geological characteristics and environmental process of permafrost, including the upper and lower boundary of the active layer under the natural surface, the seasonal freeze–thaw

Qingbai Wu; Bin Shi; Hsai-Yang Fang

2003-01-01

40

Radiogenic strontium-87 as an index of geologic processes  

USGS Publications Warehouse

The abundance of radiogenic Sr87 relative to Sr86 at the time of crystallization has been determined for 45 rocks. The total range in the ratio Sr87/Sr86 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 Sr87/Sr86 ratios; however, there is a definite trend with geologic time. Pre-cambrian rocks give values as low as 0.700. The data indicate that Sr87/Sr86 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.

Hedge, C. E.; Walthall, F. G.

1963-01-01

41

Refining Martian Ages and Understanding Geological Processes From Cratering Statistics  

NASA Technical Reports Server (NTRS)

Senior Scientist William K. Hartman presents his final report on Mars Data Analysis Program grant number NAG5-12217: The third year of the three-year program was recently completed in mid-2005. The program has been extremely productive in research and data analysis regarding Mars, especially using Mars Global Surveyor and Mars Odyssey imagery. In the 2005 alone, three papers have already been published, to which this work contributed.1) Hartmann, W. K. 200.5. Martian cratering 8. Isochron refinement and the history of Martian geologic activity Icarus 174, 294-320. This paper is a summary of my entire program of establishing Martian chronology through counts of Martian impact craters. 2) Arfstrom, John, and W. K. Hartmann 2005. Martian flow features, moraine-like rieges, and gullies: Terrestrial analogs and interrelationships. Icarus 174,32 1-335. This paper makes pioneering connections between Martian glacier-like features and terrestrial glacial features. 3) Hartmann, W.K., D. Winterhalter, and J. Geiss. 2005 Chronology and Physical Evolution of Planet Mars. In The Solar System and Beyond: Ten Years of ISSI (Bern: International Space Science Institute). This is a summary of work conducted at the International Space Science Institute with an international team, emphasizing our publication of a conference volume about Mars, edited by Hartmann and published in 2001.

Hartmann, William K.

2005-01-01

42

Marine Geology of the Southwestern San Juan Islands: New Insights From Multibeam Imagery and Processed Aeromagnetic Data  

NASA Astrophysics Data System (ADS)

The San Juan Islands, located in the seismically active northern Puget Sound, have a complicated and not yet fully understood geologic history. This study is among the first marine geologic mapping efforts within the San Juan Islands, filling an important gap in an otherwise well-studied region. Existing geologic and geophysical data were combined with interpretations of new multibeam bathymetry and backscatter seafloor imagery to construct a seamless onshore - offshore geologic map of the southwestern San Juan Islands. Simrad EM1002 (95 kHz) and Reson 8101 (240 kHz) multibeam bathymetry and backscatter data were collected between October 2000 and November 2003 within Haro Strait, northeastern Strait of Juan de Fuca, and San Juan Channel. Sun-shaded images of the processed data reveal a complex network of faulted and fractured bedrock exposures, deep glaciated channels, Pleistocene glacial sediments, and dynamic bedforms. Distinct slump morphologies in multibeam and backscatter imagery suggest active slumping of recent sediments at the mouth of San Juan Channel. A number of previously inferred offshore geologic structures were extended and constrained based on distinct linear bedrock features visible in the multibeam imagery. Aeromagnetic data collected by the U.S. Geological Survey in 1997 were processed to accentuate short-wavelength, presumably shallow, magnetic sources. The resultant derivative aeromagnetic map reveals a number of areas with distinctive anomaly patterns. Gradients in magnetic anomalies often corresponded with fault traces identified in high-resolution multibeam imagery and may reflect slight magnetic susceptibility contrasts across fault contacts. Aeromagnetic data also constrain two tectonostratigraphic terrane boundaries not identified in multibeam imagery: 1) the Buck Bay fault, which separates the Lopez Structural Complex and Decatur terrane from the underlying Constitution Formation, and 2) the Haro fault separating the Deadman Bay terrane of the San Juan Thrust system from the Wrangellia terrane on Vancouver Island.

Tilden, J. E.; Greene, H. G.; Blakely, R. J.

2004-12-01

43

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

44

Marine Geology of the Southwestern San Juan Islands: New Insights From Multibeam Imagery and Processed Aeromagnetic Data  

Microsoft Academic Search

The San Juan Islands, located in the seismically active northern Puget Sound, have a complicated and not yet fully understood geologic history. This study is among the first marine geologic mapping efforts within the San Juan Islands, filling an important gap in an otherwise well-studied region. Existing geologic and geophysical data were combined with interpretations of new multibeam bathymetry and

J. E. Tilden; H. G. Greene; R. J. Blakely

2004-01-01

45

Impact craters: their importance in geologic record and implications for natural resource development  

Microsoft Academic Search

Impacting bodies of sufficient size traveling at hypervelocities carry tremendous potential energy. This relatively infrequent process results in the instantaneous formation of unique structures that are characterized by extensive fracturing and brecciation of the target material. Impacts onto continental shield areas can create rich ore deposits, such as the Sudbury mining district in Canada. Impacts into the sedimentary column can

D. Jr

1986-01-01

46

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.

47

Processes in karst systems, physics, chemistry, and geology  

SciTech Connect

Dreybrodt deals quantitatively with many of the chemical and hydrological processes involved in the formation of karst systems. The book is divided into 3 major parts. The first part develops the basic chemical and fluid-flow principles needed in modeling karst systems. The second part investigates the experimental kinetics of calcite dissolution and precipitation and applies the resulting kinetic laws to the modeling of these processes in systems both open and closed to carbon dioxide. The last part of the book includes a qualitative examination of karst systems, quantitative modeling of the development of karst features, and an examination and modeling of the growth of spelotherms in caves.

Dreybrodt, W.

1988-01-01

48

Modeling coupled Thermo-Hydro-Mechanical processes including plastic deformation in geological porous media  

NASA Astrophysics Data System (ADS)

There has been an increasing interest in the recent years in developing computational tools for analyzing coupled thermal, hydrological and mechanical (THM) processes that occur in geological porous media. This is mainly due to their importance in applications including carbon sequestration, enhanced geothermal systems, oil and gas production from unconventional sources, degradation of Arctic permafrost, and nuclear waste isolation. Large changes in pressures, temperatures and saturation can result due to injection/withdrawal of fluids or emplaced heat sources. These can potentially lead to large changes in the fluid flow and mechanical behavior of the formation, including shear and tensile failure on pre-existing or induced fractures and the associated permeability changes. Due to this, plastic deformation and large changes in material properties such as permeability and porosity can be expected to play an important role in these processes. We describe a general purpose computational code FEHM that has been developed for the purpose of modeling coupled THM processes during multi-phase fluid flow and transport in fractured porous media. The code uses a continuum mechanics approach, based on control volume - finite element method. It is designed to address spatial scales on the order of tens of centimeters to tens of kilometers. While large deformations are important in many situations, we have adapted the small strain formulation as useful insight can be obtained in many problems of practical interest with this approach while remaining computationally manageable. Nonlinearities in the equations and the material properties are handled using a full Jacobian Newton-Raphson technique. Stress-strain relationships are assumed to follow linear elastic/plastic behavior. The code incorporates several plasticity models such as von Mises, Drucker-Prager, and also a large suite of models for coupling flow and mechanical deformation via permeability and stresses/deformations. In this work we present several example applications of such models.

Kelkar, S.; Karra, S.; Pawar, R. J.; Zyvoloski, G.

2012-12-01

49

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

50

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

51

Use of clay minerals in reconstructing geological processes: recent advances and some perspectives  

Microsoft Academic Search

This article reviews that clay literature from the last ten years, which is devoted to the applications of clay minerals in the interpretation of geological processes in sedimentary basins. The results, selected by the author as being of particular interest, are presented, arranged according to the successive phases of the rock cycle. The research field defined in the title has

J. Srodon

1999-01-01

52

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

53

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

USGS Publications Warehouse

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 ~350 m to ~2 km. The SAR data are distributed over a wide latitudinal and longitudinal range, enabling some conclusions to be drawn about the global distribution of processes. They reveal a geologically complex surface that has been modified by all the major geologic processes seen on Earth - volcanism, tectonism, impact cratering, and erosion and deposition by fluvial and aeolian activity. In this paper, we map geomorphological units from SAR data and analyze their areal distribution and relative ages of modification in order to infer the geologic evolution of Titan's surface. We find that dunes and hummocky and mountainous terrains are more widespread than lakes, putative cryovolcanic features, mottled plains, and craters and crateriform structures that may be due to impact. Undifferentiated plains are the largest areal unit; their origin is uncertain. In terms of latitudinal distribution, dunes and hummocky and mountainous terrains are located mostly at low latitudes (less than 30 degrees), with no dunes being present above 60 degrees. Channels formed by fluvial activity are present at all latitudes, but lakes are at high latitudes only. Crateriform structures that may have been formed by impact appear to be uniformly distributed with latitude, but the well-preserved impact craters are all located at low latitudes, possibly indicating that more resurfacing has occurred at higher latitudes. Cryovolcanic features are not ubiquitous, and are mostly located between 30 degrees and 60 degrees north. We examine temporal relationships between units wherever possible, and conclude that aeolian and fluvial/pluvial/lacustrine processes are the most recent, while tectonic processes that led to the formation of mountains and Xanadu are likely the most ancient.

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

2010-01-01

54

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

USGS Publications Warehouse

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 ???350 m to ???2 km. The SAR data are distributed over a wide latitudinal and longitudinal range, enabling some conclusions to be drawn about the global distribution of processes. They reveal a geologically complex surface that has been modified by all the major geologic processes seen on Earth - volcanism, tectonism, impact cratering, and erosion and deposition by fluvial and aeolian activity. In this paper, we map geomorphological units from SAR data and analyze their areal distribution and relative ages of modification in order to infer the geologic evolution of Titan's surface. We find that dunes and hummocky and mountainous terrains are more widespread than lakes, putative cryovolcanic features, mottled plains, and craters and crateriform structures that may be due to impact. Undifferentiated plains are the largest areal unit; their origin is uncertain. In terms of latitudinal distribution, dunes and hummocky and mountainous terrains are located mostly at low latitudes (less than 30??), with no dunes being present above 60??. Channels formed by fluvial activity are present at all latitudes, but lakes are at high latitudes only. Crateriform structures that may have been formed by impact appear to be uniformly distributed with latitude, but the well-preserved impact craters are all located at low latitudes, possibly indicating that more resurfacing has occurred at higher latitudes. Cryovolcanic features are not ubiquitous, and are mostly located between 30?? and 60?? north. We examine temporal relationships between units wherever possible, and conclude that aeolian and fluvial/pluvial/lacustrine processes are the most recent, while tectonic processes that led to the formation of mountains and Xanadu are likely the most ancient. ?? 2009 Elsevier Inc.

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

2010-01-01

55

Linking Geologic Framework to Nearshore Processes and Shoreline Change: Results from the Outer Banks of North Carolina  

NASA Astrophysics Data System (ADS)

Within the coastal geology community, a consensus appears to have developed that the geologic framework of the inner-shelf plays an important role in shoreline change. It has yet to be determined, however, whether geology exerts a first-order control on shoreline dynamics and, if so, across what time and spatial scales. Furthermore, principal mechanisms that may link underlying geology and shoreline behavior remain poorly understood and untested. To this end, an extensive survey of the seafloor surface and shallow sub-bottom utilizing an interferometric swath bathymetry sonar system and a chirp sub-bottom profiler mounted on an amphibious vessel was conducted across the surf zone of the Outer Banks of North Carolina. Recent findings from a small region near Duck, North Carolina suggest a connection between partial exposure of pre-modern, non-sandy substrates in the surf zone and bar morphodynamics leading to the repeated occurrence of shoreline hotspots. Support from the US Geological Survey, US Army Corps of Engineers, and the Army Research Office has expanded this work to include a 40 km length of surf zone extending from Duck to Nags Head, North Carolina. Preliminary results from the larger survey are consistent with earlier findings at Duck which show: 1) an underlying ravinement surface with very irregular relief across the surf zone; 2) a thin cover of modern sand, ranging from 0 to a maximum of 2.5 m thick, with a surface morphology that does not necessarily mirror the underlying topography; 3) the presence of large transverse bars located beside exposures of non-sandy substrate; and 4) a spatial correlation between hotspots and regions with exposed non-sandy substrates and transverse bars in the surf zone. Future work will examine shoreline behavior and bar morphodynamics associated with the geologic framework of the nearshore over event and seasonal time scales. These observations will be designed to provide insight into the processes responsible for hotspot formation and to identify key geologic variables that could be incorporated into, and ultimately, improve shoreline evolution models.

McNinch, J. E.; Miselis, J. L.; Schupp, C. A.

2002-12-01

56

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

57

The Importance of Biophysicochemical Transport Processes in Hyporheic Exchange  

NASA Astrophysics Data System (ADS)

Hyporheic exchange processes are generally analyzed in terms of hydrologic stream-subsurface interactions, biogeochemical reactions in the hyporheic zone, or nutrient and carbon uptake in the context of stream metabolism. Often, investigations are motivated primarily by applications in hydrology, contaminant transport, or stream ecology, and thus focus on only one of these aspects of hyporheic exchange. However, it is important to consider the interrelationships between biological, physical, and chemical processes, which are inevitably and inextricably linked because the hyporheic zone represents an extraordinary complex environmental system. The nature of biophysicochemical linkages in the hyporheic zone will be discussed in general terms and illustrated with two important examples. The transport of microorganisms such as the pathogen Cryptosporidium parvum in streams is dependent on both physical transport processes and physicochemical interactions in the hyporheic zone. The transport of labile particulate organic matter to the hyporheic zone is dependent on similar processes, but also induces biologically-mediated alteration of the subsurface environment. In these types of studies, insufficient characterization of either physical, chemical, or biological processes can lead to errors in interpretation of overall system behavior.

Packman, A. I.

2001-12-01

58

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

59

Laboratory Studies of Heterogeneous Chemical Processes of Atmospheric Importance  

NASA Technical Reports Server (NTRS)

The objective of this study is to conduct measurements of chemical kinetics parameters for heterogeneous reactions of importance in the stratosphere and the troposphere. It involves the elucidation of the mechanism of the interaction of HCl vapor with ice surfaces, which is the first step in the heterogeneous chlorine activation processes, as well as the investigation of the atmospheric oxidation mechanism of soot particles emitted by biomass and fossil fuels. The techniques being employed include turbulent flow-chemical ionization mass spectrometry and optical ellipsometry, among others.

Molina, Mario J.

2004-01-01

60

Silicate Carbonation Processes in Water-Bearing Supercritical CO2 Fluids: Implications for Geologic Carbon Sequestration  

NASA Astrophysics Data System (ADS)

Global climate change is viewed by many as an anthropogenic phenomenon that could be mitigated through a combination of conservation efforts, alternative energy sources, and the development of technologies capable of reducing carbon dioxide (CO2) emissions. Continued increases of atmospheric CO2 concentrations are projected over the next decade, due to developing nations and growing populations. One economically favorable option for managing CO2 involves subsurface storage in deep basalt formations. The silicate minerals and glassy mesostasis basalt components act as metal cation sources, reacting with the CO2 to form carbonate minerals. Most prior work on mineral reactivity in geologic carbon sequestration settings involves only aqueous dominated reactions. However, in most sequestration scenarios, injected CO2 will reside as a buoyant fluid in contact with the sealing formation (caprock) and slowly become water bearing. Comparatively little laboratory research has been conducted on reactions occurring between minerals in the host rock and the wet scCO2. In this work, we studied the carbonation of wollastonite [CaSiO3] exposed to variably wet supercritical CO2 (scCO2) at a range of temperatures (50, 55 and 70 °C) and pressures (90,120 and 160 bar) in order to gain insight into reaction processes. Mineral transformation reactions were followed by two novel in situ high pressure techniques, including x-ray diffraction that tracked the rate and extents of wollastonite conversion to calcite. Increased dissolved water concentrations in the scCO2 resulted in increased carbonation approaching ~50 wt. %. Development of thin water films on the mineral surface were directly observed with infrared (IR) spectroscopy and indirectly with 18O isotopic labeling techniques (Raman spectroscopy). The thin water films were determined to be critical for facilitating carbonation processes in wet scCO2. Even in extreme low water conditions, the IR technique detected the formation of amorphous silica. Unlike the thick (<10 ?m) passivating silica layers observed in the reacted samples from fully water saturated scCO2 experiments, images obtained from a focused ion beam sectioned sample indicted these coatings were chemically wollastonite but structurally amorphous. In addition, evidence of an intermediate hydrated amorphous calcium carbonate forming under these conditions further emphasize the importance of understanding geochemical processes occurring in water-bearing scCO2 fluids.

Miller, Q. R.; Schaef, T.; Thompson, C.; Loring, J. S.; Windisch, C. F.; Bowden, M. E.; Arey, B. W.; McGrail, P.

2012-12-01

61

Theoretical studies of important processes in planetary and comet atmospheres  

NASA Technical Reports Server (NTRS)

Dissociative recombination (DR) reactions in planetary and comet atmospheres are discussed. A computer program was developed which determines DR cross sections and rates using potential curves and electronic capture widths. It uses Multi-Channel Quantum Defect Theory (MQDT) to include excited Rydberg resonance levels in the DR cross section and rate calculations. Each vibrational level of a molecular ion is the limit for an infinite series of Rydberg states. Above each ion vibrational level are Rydberg vibrational levels having higher ion levels as their series limit. These Rydberg vibrational levels are resonances, i.e., neutral states which are imbedded in the electron-molecular ion continuum. The process in which the Rydberg level causes an abrupt perturbation in the cross section for DR (because of interference between capture into the Rydberg level and capture into the repulsive dissociative state) is referred to as indirect recombination. The process in which the Rydberg levels are excluded and recombination goes from the entrance channel to the repulsive state is called direct recombination. The full DR process, i.e., both direct and indirect recombination, is the process of importance for planetary atmospheres. These ideas are illustrated with the new results for DR from excited ion vibrational levels of O2(+) into the dissociative state which leads to O(1S) + O(1D).

Guberman, Steven L.

1990-01-01

62

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

63

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

64

Laboratory Studies of Heterogeneous Chemical Processes of Atmospheric Importance  

NASA Technical Reports Server (NTRS)

The objective of this study is to conduct measurements of chemical kinetics parameters for heterogeneous reactions of importance in the stratosphere and the troposphere. It involves the elucidation of the mechanism of the interaction of HC1 vapor with ice surfaces, which is the first step in the heterogeneous chlorine activation processes, as well as the investigation of the atmospheric oxidation mechanism of soot particles emitted by biomass and fossil fuels. The techniques being employed include turbulent flow- chemical ionization mass spectrometry and optical ellipsometry, among others. The next section summarizes our research activities during the first year of the project, and the section that follows consists of the statement of work for the second year.

Molina, Mario J.

2003-01-01

65

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

66

Quantitative Geological Surface Processes Extracted From Infrared Spectroscopy and Remote Sensing  

NSDL National Science Digital Library

This 17-page PDF document from Michael Ramsey at the University of Pittsburg explores some of the practical applications of Thermal Infrared (TIR) data in both the laboratory and remotely acquired environments. It focuses on the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) in particular, but also mentions other systems and the caveats of moving from laboratory-based hypotheses to real world data. The document discusses the principles of TIR, highlighting the common analytical technique of spectral deconvolution as it is applied to two very different geologic processes. Case studies at the Kelso Dunes, CA and Bezimmiany Volcano, Russia, are used as primary examples that highlight TIR applications to eolian and volcanological processes. Graphs and photos help illustrate the concepts.

Ramsey, Michael S.; Pittsburgh, University O.

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

Theoretical Studies of Important Processes in Planetary and Comet Atmospheres  

NASA Technical Reports Server (NTRS)

Using theoretical quantum chemical calculations, I have successfully described the dissociative recombination (DR) of O2(+) leading to the excited S-1 state of atomic oxygen, the upper state of the well known green line emission. The process is described by O2(+) + e(-) yields O(S-1)) + O(D-1) (1) where e(-) is an electron and the product oxygen atoms are both excited. This process is important in the atmospheres of Venus, Mars and Earth. I have shown in prior calculations that only one repulsive potential curve of O2, f(sup l)Sigma(sub u, sup +) can generate O(S-1) from DR of the lowest vibrational levels of O2(+). However, in the prior results, the calculated quantum yield (i.e. the number of O(S-1) atoms produced for every two product atoms) from the O2(+) v = 0 level was smaller than the laboratory and atmospheric measurements by more than an order of magnitude. Including only direct recombination, the calculated quantum yield for O(S-1) is only 0.0016. In a calculation that accounts for both direct and indirect recombination, the quantum yield is 0.0012. The range of experimentally determined quantum yields is between 0.01 and 0.23. Because of this large difference between the theoretical and experimental quantum yields, it was thought for some time that the ionospheric and laboratory O2(+) must be vibrationally excited since for excited levels, theory gave quantum yields that are similar to experimental yields. It was also suggested that some other process was generating O(S-1) but none could be identified. Under current NASA support, I have found that reaction (1) proceeds via an unusual mechanism. The f(sup 1)Sigma(sub u, sup,+) state does not cross the ion between the turning points of the v = 0 level of the O2(+) ground state. The lack of a favorable crossing leads to a very small calculated DR rate coefficient. However, this mechanism assumes that initial electron capture must occur into the repulsive state that leads to )(S-1). Instead, I have found that initial electron capture occurs mostly into the B(sup 3)Sigma(sup u, sub -) state which crosses the ion between the turning points of the v = 0 ion level and has a large DR rate coefficient. The B state dissociates to O(D-1) and )(P-3). After capture, some of the flux is transferred to the f(sup 1)Sigma(sup u, sub +) state via symmetry mixed intermediate Rydberg states. The neutral Rydberg states are a mixture of Sigma(sub u, sup +)-1 and Sigma(sub u, sup -)-3 symmetry.

Guberman, Steven L.

1998-01-01

69

Titan's topography as a clue to geologic processes and landscape evolution  

NASA Astrophysics Data System (ADS)

Cassini has revealed a diversity of surface features on Titan rivaled by few bodies in the Solar System. Some of these features are readily identified: dunes, channels, lakes, seas, fresh impact craters, and mountains. Others are enigmatic and in some cases have sparked debate about their mode of origin. Given the limited resolution of the Cassini images, at best 300 m for synthetic aperture RADAR (SAR) images, it can be difficult to identify details that might confirm a particular mode of origin. Supplementing the images with topographic information provides an important and sometimes crucial clue to the origin and evolution of landforms. Topographic profiles from altimetry and SARTopo analysis of the images can shed light on simpler features (e.g., dunes) and led to the surprising conclusion that Titan's largest feature, Xanadu, is not elevated as had been supposed. For more complex structures, digital topographic models (DTMs) provide a full three-dimensional view. About 10% of Titan's surface has been imaged in stereo by RADAR, and we have produced DTMs of about 2% by analyzing these stereopairs. Analysis of the results within the Cassini RADAR team has shed light on a number of geologic problems: * Some putative volcanic features (e.g., the supposed dome Ganesa Macula and various diffuse surface flows) have been shown to lack the expected relief, greatly weakening the case for their volcanic origin. * Conversely, flows in Hotei Regio have been shown to tower over nearby fluvial channels, and those near Sotra Facula are associated with multiple edifices and caldera-like pits, strengthening the case for a volcanic origin. * Depths of the handful of definite impact craters measured so far range from Ganymede-like to nearly zero, and are statistically consistent with a process such as eolian deposition that would steadily reduce the crater depth rather than a process such as surface erosion that would tend to leave craters only partially filled. * Clustering of the small north-polar lakes at a few discrete levels, all of which are hundreds of meters above the major seas, suggests that these bodies of liquid are connected locally but not (over relevant timescales) regionally by subsurface flow. * Evidence for topographic "benches" at multiple levels around the seas suggests that the liquid level has fluctuated over time, perhaps as a result of inter-hemispheric transport of volatiles over multi-seasonal timescales. These examples come primarily from Titan's northern hemisphere and equatorial zone. Cassini's extended mission to date has yielded extensive coverage of the southern hemisphere that we have recently integrated into a global control network, allowing us to begin producing DTMs of multiple southern hemisphere sites with consistent absolute elevations. Of particular interest are apparent basins, for the most part empty of surface liquid, near the South Pole. Are the basin floors or possible shoreline features at consistent elevations? How do the depths and absolute elevations compare to Ontario Lacus and the other small lakes (including transient ones) in the south, and to the lakes and seas of the northern hemisphere? Topomapping now under way will help address these and other questions about the evolution of Titan's southern hemisphere and its volatile distribution over time.

Kirk, R. L.

2012-12-01

70

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

71

New processing of Luna archive panoramas and geologic assessment of the Lunokhod landing sites  

NASA Astrophysics Data System (ADS)

From the successful Soviet lunar missions Luna-9, Luna-13, Luna-17 (Lunokhod-1), Luna-20 and Luna-21 (Lunokhod-2) about 350 panoramas of the lunar surface were returned [2, 5, 11]. Unfortunately, only a small part of the data from the missions has been converted to digital form and made available for the scientific community. The main purpose of the FP7-project "PRoViDE" is to give scientists and the public access to data products from planetary surfaces of uniform quality (http://www.providespace. eu/). The MIIGAiK Extraterrestrial Laboratory (MExLab) task is to re-process lunar panoramas based on modern techniques [9], and then to subject them to more detailed geologic analyses [1, 3, 4].

Karachevtseva, I.; Kozlova, N.; Nadezhdina, I.; Zubarev, A.; Abdrakhimov, A.; Basilevsky, A.; Oberst, J.

2013-09-01

72

Development of a requirements management system for technical decision - making processes in the geological disposal project  

SciTech Connect

NUMO (Nuclear Waste Management Organization of Japan) has a responsibility for implementing geological disposal of vitrified HLW (High-Level radioactive Waste) in the Japanese nuclear waste management programme. Its staged siting procedure was initiated in 2002 by an open call for volunteer sites. Careful management strategy and methodology for the technical decision-making at every milestone are required to prepare for the volunteer site application and the site investigation stages after that. The formal Requirement Management System (RMS) is planned to support the computerized implementation of the specific management methodology, termed the NUMO Structured Approach (NSA). This planned RMS will help for comprehensive management of the decision-making processes in the geological disposal project, change management towards the anticipated project deviations, efficient project driving such as well programmed R and D etc. and structured record-keeping regarding the past decisions, which leads to soundness of the project in terms of the long-term continuity. The system should have handling/management functions for the database including the decisions/requirements in the project in consideration, their associated information and the structures composed of them in every decision-making process. The information relating to the premises, boundary conditions and time plan of the project should also be prepared in the system. Effective user interface and efficient operation on the in-house network are necessary. As a living system for the long-term formal use, flexibility to updating is indispensable. In advance of the formal system development, two-year activity to develop the preliminary RMS was already started. The purpose of this preliminary system is to template the decision/requirement structure, prototype the decision making management and thus show the feasibility of the innovative RMS. The paper describes the current status of the development, focusing on the initial stage including work analysis/modeling and the system conceptualization. (authors)

Hiroyoshi Ueda; Katsuhiko Ishiguro; Kazumi Kitayama [Nuclear Waste Management Organization of Japan (NUMO), Mita NN Bldg., 1-23, Shiba 4-Chome, Minato-ku, Tokyo 108-0014 (Japan); Kiyoshi Oyamada [JGC Corporation (Japan); Shoko Sato [Obayashi Corporation (Japan)

2007-07-01

73

Increased importance of the documented development stage in process validation?  

PubMed Central

Current trends in pharmaceutical quality assurance moved when the Federal Drug Administration (FDA) of the USA published its new guideline on process validation in 2011. This guidance introduced the lifecycle approach of process validation. In this short communication some typical changes from the point of view of practice of API production are addressed in the light of inspection experiences. Some details are compared with the European regulations.

Mohammed-Ziegler, Ildiko; Medgyesi, Ildiko

2011-01-01

74

Increased importance of the documented development stage in process validation.  

PubMed

Current trends in pharmaceutical quality assurance moved when the Federal Drug Administration (FDA) of the USA published its new guideline on process validation in 2011. This guidance introduced the lifecycle approach of process validation. In this short communication some typical changes from the point of view of practice of API production are addressed in the light of inspection experiences. Some details are compared with the European regulations. PMID:23960802

Mohammed-Ziegler, Ildikó; Medgyesi, Ildikó

2012-07-01

75

Theoretical studies of important processes in planetary and comet atmospheres  

NASA Technical Reports Server (NTRS)

The dissociative recombination (DR) of the AB(+) molecular ion with an electron has been shown to be an important component in the detailed interpretation of planetary ionosphere data. A first principles theoretical approach is developed for calculating the DR cross sections and rates for AB(+) molecular ions. The calculations focus on O2(+) and N2(+) DR, and are the first to include the indirect DR mechanism (Ryberg vibrational levels below v = 0 level of ion) for a molecule larger than H2(+). The importance of electron capture width in calculating the cross sections and rates is also examined. Electron capture widths are given for all states of O2 that are of importance to DR (lowest 10 vibrational levels of ion). Knowledge of the details of dissociative recombination will be needed for interpretation of data from future interplanetary and comet atmospheric studies.

Guberman, Steven L.

1991-01-01

76

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.

2013-01-01

77

New processing of Cassini/VIMS data on potentially geologically varying regions  

NASA Astrophysics Data System (ADS)

We present a study of Titan's geology with a view to enhance our current understanding of the satellite's potentially geologically varying regions. We apply here a statistical method, the Principal Component Analysis (PCA) [1, 2] and a radiative transfer method [3, 1] on three potentially "active" regions on Titan, i.e. regions possibly subject to change over time (in brightness and/or in color etc) [4] namely Tui Regio, Hotei Regio, and Sotra Facula. With our method of PCA we have managed to isolate specific regions of distinct and diverse chemical composition. Then, with our follow-up RT method, we retrieved the surface albedo of the three isolated regions and of the surrounding terrains with different spectral response. These methods enabled us to evaluate the atmospheric contribution and allowed us to better constrain the real surface alterations, by comparing the spectra of these regions. Finally, the temporal surface variation of Hotei Regio as suggested by Nelson et al. 2009 [5], has been tested through the use of the RT method while we have superimposed this area's Cassini Visual and Infrared Mapping Spectrometer (VIMS) and RADAR data in order to 'view' the morphological potential. Even though we have used exactly the same dataset as Nelson and coauthors in 2009, we did not detect any significant surface albedo variations over time; this led us to revise the definition of "active" regions: even if these regions have not visually changed over the course of the Cassini mission, the determination of the chemical composition and the correlation with the morphological structures [6] observed in these areas do not rule out that past and/or ongoing cryovolcanic processes are still a possible interpretation.

Solomonidou, A.; Hirtzig, M.; Bratsolis, E.; Bampasidis, G.; Coustenis, A.; Kyriakopoulos, K.; Le Mouélic, S.; Rodriguez, S.; Jaumann, R.; Stephan, K.; Drossart, P.; Sotin, C.; Brown, R. H.; Seymour, K.; Moussas, X.

2012-09-01

78

Collection & Processing of Medically Important Arthropods for Arbovirus Isolation.  

ERIC Educational Resources Information Center

The methods given for collecting, preserving, and processing mosquitoes and other archropods for isolation of arboviruses are those used by the National Communicable Disease Center. Techniques of collecting mosquitoes as they bite, using light or bait traps, and from their daytime resting sites are described and illustrated. Details of subsequent…

Sudia, W. Daniel; Chamberlain, Roy W.

79

Physical and Chemical Processes Affecting Permeability during Geologic Carbon Sequestration in Arkose and Dolostone: Experimental Observations  

NASA Astrophysics Data System (ADS)

Geologic carbon sequestration in saline sedimentary basins provides a promising option to reduce anthropogenic CO2 emissions. We are conducting experiments using a novel flow system at elevated temperatures and pressures to better understand the physical and chemical processes that result from CO2 injection into these basins and the effects of these processes on system permeability. Here we present experimental results on arkose (primarily K-feldspar and quartz) and dolostone, focusing on CO2 exsolution and fluid-mineral reactions. Following heating-induced CO2 exsolution in an arkose sediment (90-125 ?m) core, XRCT scans revealed abundant pores several times larger than the average grain size. The pores likely grew as exsolved CO2 accumulated in the pores and exerted outspread forces on the surrounding grains. These trapped CO2 accumulations blocked flow pathways, reducing measured permeability by 10,000 times. Another reported experiment on a solid arkose core and water with aqueous CO2 concentrations at 80% saturation dissolved K-feldspar, as evidenced by 3 to 1 ratios of Si to K in sampled fluids, and precipitated an Al-rich mineral, likely gibbsite. SEM images revealed extensive clay precipitation on K-feldspar mineral surfaces. Alteration reduced permeability from 5 × 10-14 m2 to 3 × 10-14 m2 during this 52-day experiment. The third reported experiment on a dolostone core and 1 molal NaCl brine with an aqueous CO2 concentration at 75% saturation caused extensive dissolution and a large increase in permeability. This three-day experiment produced a wormhole of 2 mm in diameter that penetrated the entire 2.6 cm long core with a diameter of 1.3 cm. High, initial Ca and Mg fluid concentrations that quickly receded imply early formation of the wormhole that grew in diameter with time. Our experimental results show that formation permeability can change dramatically from both physical and chemical processes, and these changes should be accounted for during geologic carbon sequestration.

Luhmann, A. J.; Kong, X.; Tutolo, B. M.; Saar, M. O.; Seyfried, W. E.

2012-12-01

80

Geologic structure and processes of the eastern Pacific margin: California and Costa Rica  

Microsoft Academic Search

The margin of the eastern Pacific has been sculpted during Tertiary geologic times by convergent and transcurrent plate motion along both continental and oceanic plate boundaries. Interpretations of central California geology predict margin development by Early Tertiary plate convergence, the transition to a transform plate boundary, and subsequent modification of that boundary. Deep penetration seismic reflection transects (EDGE profiles) provide

Kirk Duncan McIntosh

1992-01-01

81

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

82

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

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 24mgkg(-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 0.3mgkg(-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

Theoretical studies of important processes in planetary and comet atmospheres  

NASA Technical Reports Server (NTRS)

This is the fifth semi-annual progress report describing research on dissociative recombination reactions in planetary and comet atmospheres. The Appendix has two papers that describe NASA supported research. Both papers have been recently accepted for publication. The first paper, 'The Generation of O(S-1) from the Dissociative Recombination of O2(+)', describes in detail the Multichannel Quantum Defect (MQDT) theory used for the calculation of dissociative recombination (DR) cross sections and rates. The application to the generation of the upper state of the atomic oxygen green line emission is of great importance to the modelling of planetary atmospheres. The second paper in the Appendix, 'Dissociative Recombination of the Ground State of N2(+)', applies the methods described in the first paper to N2(+). We find remarkable agreement with the prior microwave afterglow experiments for both the total recombination rate and for its electron temperature dependence. However, the results disagree with recent merged beams results which gave cross sections that are a factor of five below the microwave afterglow experiments and the current results. DR of N2(+) is an important mechanism for generating energetic N atoms which can escape the atmosphere of Mars. Currently we are also continuing additional work on the DR of O2(+) which is aimed at calculating both the total DR rate as a function of ion vibrational level and the rate for production of O(D-1).

Guberman, Steven L.

1991-01-01

85

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

86

Importance of post collision interactions for charge transfer process  

NASA Astrophysics Data System (ADS)

Recently experimental fully differential cross sections (FDCS) have been reported for double capture, single capture and transfer excitation in proton helium collisions. In case of double capture, the proton captures both of the electrons from helium and leaves the collision as a H- ion. For single capture, the proton captures one electron from helium and leaves the other electron in the ground state. Transfer excitation is similar to single capture except the target is excited to an excited state. Recently experiments performed for proton energies ranging from 25keV to 300keV. We introduce here a theoretical model for charge transfer processes which is fully quantum mechanical and takes all post collision interactions (PCI) between the particles into account exactly. Numerically, this requires a full nine-dimensional integral which is computationally expensive. The theoretical results will be compared with absolute experimental measurements.

Chowdhury, Uttam; Harris, Allison; Peacher, Jerry; Madison, Don

2012-06-01

87

In Situ Optical Observation of High-Temperature Geological Processes With the Moissanite Cell  

Microsoft Academic Search

A major drawback of existing techniques in experimental earth and material sciences is the inability to observe ongoing high-temperature processes in situ during an experiment. Examples for important time-dependent processes include the textural development of rocks and oxide systems during melting and crystallization, solid-state and melt-present recrystallization and Ostwald ripening, and bubble nucleation and growth during degassing of glasses and

N. Walte; H. Keppler

2005-01-01

88

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

89

Upscaling of two-phase flow processes in CO2 geological storage  

NASA Astrophysics Data System (ADS)

Only few current multiphase flow and reactive transport models take into account the impact of heterogeneity on front spreading and mass transfer between high and low permeability zones of the heterogeneous medium and the impact of physical heterogeneity and chemical heterogeneity on chemical reactions rates. Effective equations are available for single-phase conservative and reactive transport and under development for multiphase flow. In the present work, we aim specifically at the upscaling of the two-phase flow dynamics related to processes of CO2 geological storage. The impact of heterogeneity on the two-phase flow dynamics can be quantified in the framework of a multi-continuum approach. This approach allows for the quantification of mass exchange between mobile (background material) and immobile (inclusions) zones of the medium. In this way it accounts systematically for local scale non-equilibrium and thus for the complex flow dynamics in highly heterogeneous and fractured media. The mass exchange between mobile and immobile zones is taken into account by a Multi-Rate Mass Transfer (MRMT) model. Effective equations were formulated in order to describe the impact of spatial heterogeneity on the large-scale two-phase flow behavior. The model was implemented into a MatLab code. Heterogeneity in the hydraulic conductivity of the storage aquifer was accounted through a Gaussian random field. Numerical simulations of 2D two-phase flow through this heterogeneous media were run to obtain the evolution of the actual CO2-rich phase saturation distribution. An equivalent effective model of 1D two-phase flow in homogenous media with MRMT was used to describe the 2D heterogeneous results. The numerical simulations show that a simple 1D homogeneous model with MRMT, capillarity at mobile-immobile interface and in the mobile zone is able to describe two-phase flow in heterogeneous media. However, gravity and macrodispersion terms still have to be included. Extension to heterogeneous multiphase flow is straightforward. The present methodology could contribute significantly to the quantification of the heterogeneity-induced uncertainty of the predicted large-scale multiphase flow and transport behavior in CO2 geological storage.

Silva, O.; Neuweiler, I.; Dentz, M.; Saaltink, M.; Carrera, J.

2012-04-01

90

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

Federal Register 2010, 2011, 2012, 2013

...the U.S. Geological Survey Science Strategy Planning Feedback...and Land Use Change, Core Science Systems, Ecosystems, Energy...Minerals, Environmental Health, Natural Hazards, and Water. This...usgs.gov/start_with_science. DATES: The comment...

2012-06-08

91

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

Federal Register 2010, 2011, 2012, 2013

...the U.S. Geological Survey Science Strategy Planning Feedback...and Land Use Change, Core Science Systems, Ecosystems, Energy...Minerals, Environmental Health, Natural Hazards, and Water. This...usgs.gov/start_with_science. DATES: The comment...

2012-07-23

92

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

Federal Register 2010, 2011, 2012, 2013

...the U.S. Geological Survey Science Strategy Planning Feedback...and Land Use Change, Core Science Systems, Ecosystems, Energy...Minerals, Environmental Health, Natural Hazards, and Water. This...usgs.gov/start_with_science. DATES: The comment...

2011-03-10

93

Geochemical Processes During Geological Carbon Storage: Lessons from Natural Analogues and Field Experiments (Invited)  

NASA Astrophysics Data System (ADS)

The nature, rates and consequences of reactions between CO2-charged brines and reservoir and caprock minerals for the long-term fate of geological carbon stores are uncertain. At worst it has been suggested that acid carbonated brines might corrode migration pathways through caprocks and fault zones allowing CO2 to escape and transporting metal contaminants. However there is a growing body of data from short term injection experiments, and sites where natural CO2 has been stored or actively leaking for 100,000's of years or more, which shows that the acid fluids are rapidly neutralised by reaction with carbonate and Fe-oxyhydroxide minerals, that the fluids precipitate carbonate minerals in caprocks and along migration pathways, and that caprocks have remained impermeable over millions of years. Limited observations from small scale injection experiments suggest that the natural heterogeneities in rock formations cause extensive fingering of the injected CO2, markedly increasing the rates of CO2 dissolution into formation brines. The resultant acidity drives the dissolution of carbonates and Fe-oxyhydroxide minerals which buffers pH, but the more sluggish dissolution of silicate minerals over time scales of months or more drives subsequent re-precipitation of carbonate minerals. Dissolution of Fe-oxide grain coatings is important in stabilizing Fe-Mg-Ca carbonate minerals. Reaction rates slow over 2 to 5 orders-of-magnitude as equilibrium is approached and in the longer term are controlled by the kinetic balance between the thermodynamic understep of the dissolution reactions of primary Si-Al phases (e.g. feldspars and micas in sandstone reservoirs) and the overstep driving the precipitation of clay minerals. Reservoir mineralogy imposes a key control on the fluid-mineral reactions where immature continental sandstones contain much higher fractions of reactive feldspars and micas than mature marine quartz sands. The major conclusion from observations to date is that fluid-mineral reactions are initially fast, are important in buffering fluid compositions and may cause important beneficial changes to formation and caprock permeabilities. However much more needs to be learnt. Many of the inferences on mineral dissolution and precipitation reactions are derived from modal decomposition calculations based on changes in sampled fluid chemistry and these suffer ambiguities arising from the limited number of soluble cations present in stoichiometric proportions in minerals and from the uncertainties in mineral compositions. The reservoirs and caprocks in natural analogues contain an inadequately sampled and exploited record of the fluid-mineral reactions but deciphering this requires careful petrographic, mineralogical and geochemical work to distinguish the response to CO2-charged fluids from earlier diagenetic episodes.

Bickle, M. J.; Kampman, N.; Wigley, M.; Dubacq, B.

2013-12-01

94

Teaching Geology  

NSDL National Science Digital Library

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

95

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

96

Geologic Maps  

NSDL National Science Digital Library

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

Graymer, Russell

97

Investigation of the geologic setting and geomorphic processes that control the formation and preservation of precarious rock zones  

NASA Astrophysics Data System (ADS)

Zones of precariously balanced rocks have been used as negative indicators of previous strong ground motion in seismically active regions of Southern California and Nevada (e.g. Brune 1996). Understanding the geologic context and the geomorphic framework that control the formation and preservation of precarious rocks is essential to testing their fidelity for extreme ground motion analyses. In this study we assess the geologic settings and the geomorphic processes nested within them using precarious rock zones (Granite Dells, Texas Canyon, and Granite Pediment) in low-seismicity regions of Arizona and Southern California. The Granite Dells locality is a ~20 km2 Proterozoic granite field that is ~5 km from the Prescott Valley graben faults (<0.2 mm/yr of Quaternary slip). The Texas Canyon locality is a ~132 km2 Mesozoic granite field that is ~23 km from the Little Rincon Mountains fault (<0.2 mm/yr of Quaternary slip). The Granite Pediment locality is a ~12 km2 Mesozoic granite pediment located ~96 km from the eastern section of the Garlock fault (<5 mm/yr of Quaternary slip). Characterization of the geologic context of each site included assembling a digital geologic database for Arizona, Southern California, and southern Nevada. The geologic database was queried for granitic bodies and Quaternary deposits. Active faults were categorized by their Quaternary slip rates, and a 20 km zone of no precarious rocks was created around each active fault based on the field surveys of Brune (1996). Aerial photographs were used to map the spatial distribution and geometry of joint sets within each site. Ground surveys using hand-held GPS units and digital photography were conducted to document the characteristics (lithology, size, fragility, weathering characteristics) and spatial density of precariously balanced rocks. Morphometric analyses of digital elevation data may indicate if there is a slope or relief range which the precarious rocks are optimally produced and/or preserved.

Haddad, D.; Arrowsmith, R.

2008-12-01

98

Cold seeps in the eastern Mediterranean a quantitative geological-biological-chemical investigation of causes, processes and implications- a preliminary seismic study  

NASA Astrophysics Data System (ADS)

Cold seepage of gas/water from the seafloor is one of the most important indications of active processes occurring in the subsurface of continental margins. The location and development of these seeps is, among other things, associated with mass sedimentary transport, resulting from slope failure (e.g. submarine landslides). Studies have shown that endemic ecological systems tend to develop in the shallow subsurface and seafloor near these sites, whose existence is directly related to utilization of the escaping gas. A large and unknown part of the carbon cycle is connected to the reduction and release of methane to the water column. However a precise evaluation of the fraction that eventually reaches the atmosphere as an important greenhouse gas is unknown. During the past few years a number of studies around the world have focused on the combination of geological, biological and chemical aspects of cold seeps. Despite this, many questions still remain unanswered, such as the geological mechanisms generating the seeps, the chemical composition of the seeps, which biological ecosystems base their existence on the seeps and how microbiological process in the subsurface effect the composition and rate of gas release. The eastern Mediterranean basin is one of the most interesting and least studied regions as far as cold seep systems are concerned. The basin is considered to be an "ecological desert" with respect to available nutrients and biological diversity. Here we present new results from a high-resolution Sparker seismic survey carried out offshore northern Israel to map the location of gas seepages on the seafloor. A number of shallow cores were extracted from the target areas and water was sampled for chemical analysis. These data will be integrated as a pilot for a larger, interdisciplinary study to identify, map and characterize the geology, biology and chemistry of gas seepages in the eastern Mediterranean.

Lazar, M.; Schattner, U.

2009-04-01

99

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

Microsoft Academic Search

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)

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

1988-01-01

100

Syndepositional dissolution of calcium carbonate in neritic carbonate environments: geological recognition, processes, potential significance  

Microsoft Academic Search

Within carbonate sediments below tropical–subtropical oceanic surface waters, syndepositional “chemical” dissolution of CaCO3 driven by organic matter oxidation can modify substantially the textural, compositional and early diagenetic characteristics of the resulting rock.Main actuogeological evidence for “chemical” dissolution includes pore-water chemistry of carbonate sediments, and corrosion of bioclasts. Geological evidence includes taphonomic bias towards bioclasts of primary low-magnesium calcite, ghosts of

Diethard Sanders

2003-01-01

101

CO2-mineral Wettability and Implications for Understanding Leakage Processes from Geologic Carbon Sequestration Sites  

NASA Astrophysics Data System (ADS)

In geological carbon sequestration (GCS), leakage events will be difficult to predict because parcels of CO2 will travel over long length scales and encounter a number of heterogeneous formations and endogenous brine in their rise to the surface. A constitutive model of a rising parcel of CO2 includes at least three main forces: 1) buoyant forces, 2) surface tension forces, and 3) shear drag forces. Of these, surface tension forces are of great significance, especially for predicting capillary and mineral trapping, and are affected by surface tension and the three-phase contact angle between CO2, brine, and the solid host mineral surfaces. Very limited experimental data on contact angles in GCS relevant systems has been reported in the academic literature. Here, the contact angle of several of the rock and clay species prevailing near GCS sites, e.g. quartz, feldspar, calcite, kaolinite, smectite and illite, were measured under a range of relevant temperature, pressure and ionic strength conditions. The measurements were made in a custom-built high-pressure view cell by introducing precisely controlled pendant CO2 droplets of constant volume to smooth and clean mineral surfaces after saturating the surrounding brine with CO2 and images were recorded using a high resolution digital camera. Images were processed and the contact angle measured using ImageJ software with a plug-in designed for this purpose. To measure the contact angle of CO2 on clay surfaces, ultra-pure microscope glass slides were coated with cleaned and particle-size-separated clay particles using hydrolyzed polyvinyl alcohol to ensure adhesion and a continuous coating on the surface. The uniform morphology of the surface was confirmed using electron microscopy. Preliminary results demonstrate differences in contact angle between the tested minerals, with calcite > quartz > feldspar. The absolute differences between the minerals were on the order of 3-7%. The results also demonstrate that under higher temperature and pressure conditions, the contact angle decreases making the minerals more strongly wetting. For calcite, the contact angle decreases from 155.9o at 7MPa, 30oC (gas phase CO2) to 149.8o at 20MPa, 50oC (supercritical phase CO2), suggesting that contact angle is impacted by both temperature and pressure but also by CO2 phase. The contact angle measurements also indicate that some mineral surfaces can undergo surface hysteresis wherein surface reactions can result in changes in the surface energy and the contact angle. Of the minerals tested here calcite was found to be the most reactive and the contact angle changed from non-wetting to wetting over the period of several hours. The measurements reported here for pure mineral species enable the development of effective contact angles for heterogeneous materials that have undergone diagenesis are common on the surfaces of the consolidated and unconsolidated media.

Clarens, A. F.; Edwards, I.; Wang, S.

2011-12-01

102

Saturnian and Uranian Satellites: relative importances of different processes responsible for their evolution  

Microsoft Academic Search

Discussion of the most important processes relevant to evolution of the icy-mineral bodies is given. The endogenic processes under considerations are: (i) radioactivity, (ii) gravitational differentiation, (iii) self compaction due to closing of the pores, and (iv) phase transitions. The main exogenic processes are: (a) impacts, (b) tidal heating, (c) solar radiation, and (d) external flux of particles. Processes of

J. Leliwa-Kopystynski; L. Czechowski

2004-01-01

103

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

104

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

105

Venus: Vertical accretion of crust and depleted mantle and implications for geological history and processes  

NASA Technical Reports Server (NTRS)

Models for the vertical accretion of a basaltic crust and depleted mantle layer on Venus over geologic time predict the eventual development of a net negatively buoyant depleted mantle layer, its foundering and its remixing with the underlying mantle. The consequences of the development of this layer, its loss, and the aftermath are investigated and compared to the geologic record of Venus revealed by Magellan. The young average age of the surface of Venus (several hundred million years), the formation of the heavily deformed tessera regions, the subsequent emplacement of widespread volcanic plains, the presently low rate of volcanic activity, and impact crater population that cannot be distinguished from a completely spatially random distribution, and the small number of impact craters embayed by volcanism, are all consistent with the development of a depleted mantle layer, its relatively rapid loss followed by large-scale volcanic flooding, and its subsequent reestablishment. We outline a 'catastrophic' tectonic resurfacing model in which the foundering of the depleted mantle layer several hundred million years ago caused globally extensive tectonic deformation and obliteration of the cratering record, accompanied by upwelling of warm fertile mantle and its pressure-release melting to produce extensive surface volcanism in the following period. Venus presently appears to be characterized by a relatively thick depleted mantle layer and lithosphere reestablished over the last several hundred million years following the previous instability event inferred to have produced the tessera terrain.

Head, James W.; Parmentier, E. M.; Hess, P. C.

1994-01-01

106

ASTER digital image processing for geological mapping: Examples from Neoproterozoic Allaqi-Heiani Suture, Egypt  

NASA Astrophysics Data System (ADS)

This dissertation constitutes three manuscripts summarizing efforts in developing effective algorithms for the analysis of the Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) data for geological mapping using the Neoproterozoic Allagi-Heiani Suture (AHS) in southern Egypt as a test site. The first manuscript presents statistical approach for the selection of ASTER bands to be used for Red-Green-Blue (RGB) color combination images. The Optimum Index Factor (OIF) and determinants techniques are proposed to rank all possible ASTER RGB color combinations for the western part of AHS. ASTER has three subsystems including Visible and Near Infra-Red (VNIR), Short Wave Infra-Red (SWIR), and Thermal Infra-Red (TIR). Hence, ASTER bands can be used in seven Electromagnetic Spectrum (EMS) regions combinations. These are VNIR only, SWIR only, TIR only, VNIR+SWIR, VNIR+TIR, SWIR+TIR, and VNIR+SWIR+TIR. The OIF and determinants results agree in four of the seven EMS regions combinations (VNIR only, SWIR only, TIR only, and VNIR+SWIR), but differ in three (VNIR+TIR, SWIR+TIR, and VNIR+SWIR+TIR). The second manuscript outlines an effective algorithm to spectrally separate ophiolite components in AHS and use these as markers to trace the continuity of geological structures. Principal component analysis (PCA), Fast Fourier Transform (FFT), and Redundant Wavelet Transform (RWT) are used to identify ophiolite components as well as Neoproterozoic ductile structures to trace along-strike continuation in AHS. This work helps trace structures along AHS and reveals structures that have not been identified before. Nappes identified in the west are traced into the central part of the suture allowing for subsequent modification by younger structures. The third manuscript outlines a methodology to quantitatively evaluate ASTER band-ratios that can be effectively used for thematic classification aimed at separating distinctive lithologies in AHS. The Within-Class Homogeneity Criteria (WHC) is proposed for the selection of specific band-ratios. The effectiveness of WHC is tested by using the classification correction evaluation curve to select fewer band-ratios. The accuracy of WHC is tested by comparing previously published geological map covering AHS with the WHC-based classification results and those based on all 14 ASTER bands and all 182 ASTER band-ratios. Commission and emission errors frequently occurred during traditional thematic classification are conquered by using WHC-based classification.

Ren, Dianwei

107

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.

108

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

109

3-Dimensional Mapping of Electrical Resistivity and Geological Data with Combination of CPTe Data for understanding the Fluid Transport Processes  

NASA Astrophysics Data System (ADS)

To understand the hydrogeological process and spatial distribution of contamination, there are several conventional methods which are gathered under two main branches that are invasive and non-invasive techniques. Standard Penetration Test and Conic Penetration Test techniques are called as classical borehole techniques and they are accepted among the invasive or less-invasive techniques. On the other hand, electrical and electromagnetic based Electrical Resistivity Tomography and Ground Penetrating Radar, most widely used techniques in imaging the subsurface in the last decade, are called as non-invasive geophysical methods. 3D electrical resistivity distribution provides information about water flow and changes in electrical resistivity of the pore fluid. Therefore, to assist in understanding and modeling of the fluid transport process, 3D spatial distribution of the electrical resistivity data with the corresponded 3D geological section were mapped and interpreted in the test site located in western Germany.

Kanli, A. I.; Nyari, Z.; Stickel, J.; Tillmann, A.

2012-12-01

110

Geologic Explorations  

NSDL National Science Digital Library

Geologic Explorations allows learners to explore a variety of unique geological formations of Utah using Quicktime Virtual Reality (QTVR) panoramas and digital still imagery. Spectacular panoramas and striking images capture Utah's unique geology and invite students to explore and learn interesting facts and concepts central to the study of geology.

Bodzin, Alec

2002-04-01

111

Geologic Maps  

NSDL National Science Digital Library

Geologic Maps are unique in that they show the distribution of geologic features on a landscape through specific symbols and colors. The United States Geological Survey's (USGS) site Geologic Maps provides visitors with a good introduction to these concepts, which include the unique features of a geologic map; the meaning of their lines, colors, and symbols; the location of faults; and more. Anyone working with geologic maps or just interested in learning a little about cartography or geology will find this site easy to explore and full of good information.

2000-01-01

112

Research on the Photon Absorption Processes of Gases Important in the Upper Atmosphere.  

National Technical Information Service (NTIS)

The results of investigations into the absorption processes of gases important in upper atmosphere chemistry and physics are presented. The principle region studied in the vacuum ultraviolet at wavelengths less than 3000 A. Methods of producing the OH rad...

J. L. Roebber

1970-01-01

113

Basic petroleum geology, 2nd Ed  

SciTech Connect

It presents the fundamental concepts of geology in terms of sedimentary deposition, petroleum occurrence, exploration, and recovery. It provides an integrated overview of petroleum geology concepts and vocabulary in easy to understand language. It is essential that geologists, geophysicists, and engineers share a common understanding of geologic processes which are presented in this book. It is just as important that petroleum managers, landmen, and technicians, as well as attorneys, financiers, and other nontechnical professionals be conversant with the terminology and fundamental principles of petroleum occurrence, exploration, and production.

Link, P.K.

1988-01-01

114

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

115

Unexpected discoveries and S-invention of design requirements: important vehicles for a design process  

Microsoft Academic Search

Designers, during a conceptual design process, do not just synthesize solutions that satisfy initially given requirements, but also invent design issues or requirements that capture important aspects of the given problem. How do they do this? What becomes the impetus for the invention of important issues or requirements? So-called `unexpected discoveries', the acts of attending to visuo-spatial features in sketches

Masaki Suwa; John Gero; Terry Purcell

2000-01-01

116

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

117

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

118

Image Gallery for Geology  

NSDL National Science Digital Library

These images of geologic phenomena are used to supplement introductory geology classes at the University of North Carolina at Chapel Hill. The images are categorized under plutonic, volcanic and sedimentary rocks; structural geology; weathering; and coastlines. There are photographs of different kinds of volcanoes; lavas and pyroclastic rocks; volcanic hazards; different types of sedimentary rocks and sedimentary structures; folds and faults; beach processes; and barrier islands.

Glazner, Allen

119

Sea Level Change, A Fundamental Process When Interpreting Coastal Geology and Geography.  

ERIC Educational Resources Information Center

Discusses the meaning of sea level change and identifies the major factors responsible for this occurrence. Elaborates on the theory and processes involved in indirect measurement of changes in sea volume. Also explains how crustal movement affects sea level. (ML)

Zeigler, John M.

1985-01-01

120

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

PubMed

Geological and climatic processes potentially alter speciation rates by generating and modifying barriers to dispersal. In Southeast Asia, two processes have substantially altered the distribution of land. Volcanic uplift produced many new islands during the Miocene-Pliocene and repeated sea level fluctuations during the Pleistocene resulted in intermittent land connections among islands. Each process represents a potential driver of diversification. We use a phylogenetic analysis of a group of Southeast Asian shrews (Crocidura) to examine geographic and temporal processes of diversification. In general, diversification has taken place in allopatry following the colonization of new areas. Sulawesi provides an exception, where we cannot reject within-island speciation for a clade of eight sympatric and syntopic species. We find only weak support for temporally declining diversification rates, implying that neither volcanic uplift nor sea level fluctuations had a strong effect on diversification rates. We suggest that dynamic archipelagos continually offer new opportunities for allopatric diversification, thereby sustaining high speciation rates over long periods of time, or Southeast Asian shrews represent an immature radiation on a density-dependent trajectory that has yet to fill geographic and ecological space. PMID:19500148

Esselstyn, Jacob A; Timm, Robert M; Brown, Rafe M

2009-10-01

121

Managing global heritage in the face of future climate change: the importance of understanding geological and geomorphological processes and hazards  

Microsoft Academic Search

It is now widely acknowledged that human adaptation of the planet is causing significant changes to the global climate, which are being felt currently and are likely to increase in the future. This is beginning to place exceptional strains on the historic environment, here defined as both above and below ground archaeological remains. Using examples from the cultural list of

Andy J. Howard

2012-01-01

122

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

NASA Astrophysics Data System (ADS)

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 ring-forming 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

123

Import, processing, and assembly of the alpha- and beta-subunits of chloroplast pyruvate dehydrogenase.  

PubMed

Sequence comparisons were used to identify cDNAs potentially encoding the alpha- and beta-subunits of chloroplast pyruvate dehydrogenase. Coupled in-vitro transcription plus translation was used to synthesize radiolabeled pyruvate dehydrogenase alpha- and beta-subunit precursor proteins. When the precursors were incubated with intact pea (Pisum sativum L.) seedling chloroplasts in the presence of ATP, they were imported and proteolytically processed. In contrast, there was no import or processing of the precursors by isolated, intact pea seedling mitochondria. Monospecific antibodies to the recombinant pyruvate dehydrogenase alpha-subunit were additionally able to co-precipitate radiolabeled pyruvate dehydrogenase beta-subunit, indicating association between subunits after import and processing. Furthermore, size-exclusion chromatography was used to identify an alphabeta heterodimer that is an intermediate in the assembly of the native alpha2beta2 heterotetrameric enzyme. PMID:10923705

Johnston, M L; Miernyk, J A; Randall, D D

2000-06-01

124

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

125

Exogenic Geological Processes as a Source of Formation of Bottom Silt in the Votkinskoe Reservoir  

Microsoft Academic Search

Experience shows that bottom silt accumulating on reservoir beds directly affects the occurrence of biological, chemical, and physical processes in the mineral substrate of the flooded river valley, in the water mass, and, in some cases, even in the low atmospheric layers [1]. Arriving from the outside and accumulating in the bowl of the reservoir the organomineral substance permanently changes

N. N. Nazarov

2002-01-01

126

Role of geology in diamond project development  

NASA Astrophysics Data System (ADS)

For a mining operation to be successful, it is important to bring fundamental and applied science together. The mining engineer needs to understand the importance of geology, mineralogy and petrography, and how projects can benefit from the data collected during the exploration and pre-exploration stage. Geological scientists also need to understand the process of project development from the exploration stage through mine design and operation to mine closure. Kimberlite pipe or dyke emplacement, geology and petrology/mineralogy are three areas that illustrate how information obtained from the geological studies could directly influence the mining method selection and the project strategy and design. Kimberlite emplacement is one of the fundamental processes that rely on knowledge of the kimberlite body geology. Although the importance of the emplacement model is commonly recognized in the resource geology, mining engineers do not always appreciate its importance to the mine design. The knowledge of the orebody geometry, character of the contact zones, internal structures and distribution of inclusions could directly influence pit wall stability (thus strip ratio), underground mining method selection, dilution, treatability, and the dewatering strategy. Understanding the internal kimberlite geology mainly includes the geometry and character of individual phases, and the orientation and character of internal structures that transect the rock mass. For any mining method it is important to know "where the less and where the more competent rocks are located" to achieve stability. On the other hand, the detailed facies studies may not be important for the resource and mine design if the rock types have similar physical properties and diamond content. A good understanding of the kimberlite petrology and mineralogy could be crucial not only to the treatability (namely diamond damage and liberation), but also to the pit wall and underground excavation stability, support design, mine safety (mudrush risk assessment) and mine dewatering. There is no doubt that a better understanding of the kimberlite and country rock geology has a direct impact on the safety and economics of the mining operations. The process of mine design can start at the beginning of kimberlite discovery by incorporating the critical geological information without necessarily increasing the exploration budget. It is important to appreciate the usefulness of fundamental geological research and its impact on increased confidence in the mine design. Such studies should be viewed as worthwhile investments, not as cost items.

Jakubec, Jaroslav

2004-09-01

127

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

128

Computer Simulation of Geologic Systems.  

National Technical Information Service (NTIS)

The Geologic Simulation Model (GSM) developed under the Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) project at the Pacific Northwest Laboratory for the Department of Energy is a quasi-deterministic process-response model which simula...

M. G. Foley

1982-01-01

129

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

130

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

131

Radiometric dating in geology  

Microsoft Academic Search

The method of dating rocks and minerals is known as geochronology. Although in principle this term could be applied to estimation of relative ages according to traditional geological observation, it is nowadays usually restricted to the quantitative measurement of geological time using the constant-rate natural process of radioactive decay. 14C dating is a technique based on measuring the residual radioactivity

R J Pankhurst

1980-01-01

132

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

133

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

134

Compositional Data Analysis of Geological Variability and Process: A Case Study  

Microsoft Academic Search

Developments in the statistical analysis of compositional data over the last two decades have made possible a much deeper\\u000a exploration of the nature of variability and the possible processes associated with compositional data sets from many disciplines.\\u000a In this paper, we concentrate on geochemical data. First, we explain how hypotheses of compositional variability may be formulated\\u000a within the natural sample

Christopher W. Thomas; John Aitchison

2005-01-01

135

Import and processing of hybrid proteins by mammalian mitochondria in vitro.  

PubMed

Normal and hybrid proteins were synthesized following transcription of pSP64 recombinant plasmids with SP6 polymerase and translation of resultant mRNAs in a rabbit reticulocyte lysate. The precursor to the rat liver mitochondrial matrix enzyme, ornithine carbamyltransferase (Mr = approximately 40,000), was efficiently imported by rat heart mitochondria in vitro and processed to mature protein. Import of the precursor to a second matrix enzyme, carbamyl-phosphate synthetase I (Mr = approximately 165,000), could not be demonstrated. However, a 33-kDa hybrid protein, bearing the precarbamyl-phosphate synthetase I signal sequence (38 amino acids) and 55 amino acids from the amino terminus of the mature enzyme, followed by the carboxyl-terminal 209 amino acids of ornithine carbamyltransferase, was imported and processed under identical conditions. The topogenic function of the preornithine carbamyltransferase signal sequence (32 amino acids) was confirmed by constructing a hybrid protein bearing the signal sequence and five amino acids of mature enzyme, followed by 250 amino acids of the cytosolic enzyme of Escherichia coli, asparagine synthetase; the hybrid was transported to the matrix compartment of heart mitochondria where processing, albeit incorrect, took place. A hybrid asparagine synthetase bearing the pre-ornithine carbamyltransferase signal sequence plus 28 amino acids of mature ornithine carbamyltransferase, however, was imported and processed with apparent fidelity. PMID:2867093

Nguyen, M; Argan, C; Lusty, C J; Shore, G C

1986-01-15

136

77 FR 38033 - Notice of Establishment of a Commodity Import Approval Process Web Site  

Federal Register 2010, 2011, 2012, 2013

We are announcing the creation of a new Plant Protection and Quarantine Web site that will provide stakeholders with information about the commodity import approval process for plants and plant products and give them the opportunity to consult with us on risk assessments as they are being drafted. We are doing this in response to stakeholder requests for more information about the commodity......

2012-06-26

137

Exploring the importance and implementation of COBIT processes in Saudi organizations: An empirical study  

Microsoft Academic Search

Purpose – The purpose of this paper is to explore the importance and implementation of the Control Objectives for Information and Related Technology (COBIT) processes in Saudi organizations. Design\\/methodology\\/approach – An empirical survey, using a self-administered questionnaire, was conducted to achieve this purpose. A total of 500 questionnaires were distributed to a selected sample of organizations in Saudi Arabia. Of

Ahmad Abu-musa

2009-01-01

138

The importance of local processes to landscape patterns of grassland vegetation diversity  

Microsoft Academic Search

This study aimed to determine the importance of local processes to variation in plant species diversity by comparing soil fertility\\/diversity relationships across and within different environments. Vegetation diversity and soil fertility were measured in four different grassland communities in southern North Island, New Zealand. Vegetation species richness, Shannon diversity (H‘) and evenness (J‘) were significantly negatively related to the concentration

Todd A. White; Kenneth J. Moore; David J. Barker

2004-01-01

139

GEOLOGIC PROCESSES AFFECTING THE QUALITY OF THE UPPER FREEPORT COAL BED, WEST-CENTRAL PENNSYLVANIA.  

USGS Publications Warehouse

The number or types of origins of the components of a coal bed cannot be determined from its bulk composition. Minerals such as quartz, calcite, and pyrite as well as macerals such as vitrinite can originate from a variety of processes that result from different depositional conditions. The Upper Freeport coal bed was studied and characterized by sampling and analyzing its mappable subunits (facies) over a 120-sq mi area in west-central Pennsylvania. The study was based on field description of mine faces and description of X-ray radiographs of core. A geochemical model proposed for the origin of facies of the Upper Freeport coal bed is consistent with interpretations of modern peat formation resulting from the interaction of climate, plant types, rainfall, ground water geochemistry, nutrient supply, and sedimentation. This model provides a means to evaluate and predict more precisely the variability of a coal resource's quality.

Stanton, R. W.; Cecil, C. B.; Pierce, B. S.; Ruppert, L. F.; Dulong, F. T.

1985-01-01

140

Slope processes in weathered volcaniclastic rocks of the Camaldoli hill (Naples, Italy): Geomorphologic and Engineering-Geological aspects  

NASA Astrophysics Data System (ADS)

Following the geological study performed by Orsi et al. (this session), the main results of a geomorphologic and engineering-geological investigation of the stability conditions of the Camaldoli hill (urban area of Naples) are here presented. The Camaldoli hill, the highest peak of the Phlegraean Fields caldera (452 m asl), is characterized by relief energy of a few hundreds of meters, and by high slope gradients, which frequently reach the verticality. Low-order, structurally controlled channels drain the hillslopes; the development of stepped longitudinal profiles in the channels is related to the alternance of rocks and soils. The geological framework of the hill represent a further factor predisposing to mass movements and soil erosion. The Camaldoli hill is in fact characterized, as already highlighted by Orsi et al., by a basal sequence of jointed weak tuffs, overlain by some tens of metres of loose, unconsolidated pyroclastic terrains, ranging in age from about 12.000 and 4.000 yrs. BP. The latter deposits are generally weathered in their upper layers, as a consequence of interaction with decay agents and of past slope instabilities. Present-day morphodynamics of the hill is ruled by the occurrence of a variety of slope processes. Shallow landslides involve the weathered portion of the youngest pyroclastic products, showing features typical of slides or falls. Such events, which usually start in the upper reaches of the slope, may undergo different evolution, essentially controlled by the local slope morphology: (i) low-mobility soil slides-debris flows on open slopes; (ii) slides/falls evolving to hyperconcentrated flows along channels. The first processes have been seldom observed on open slopes, while the transition from slides/falls to hyperconcentrated flows along channels seems much more diffuse in the study area. The flows are generally fed, under intense to extreme rainfall events, by the re-mobilization of pre-existing landslide debris. The upper tuff formations (namely, the Neapolitan Yellow Tuff) are involved in falls and topple failures, which can detach volumes up to some tens of cubic metres, frequently reaching the lowest sectors of the slope, close to, if not within, the urbanized area. Eventually, accelerated soil erosion plays a major role in the open slopes, where evidences of sheet, rills and gullies have been surveyed. Joining the contribution of volcanologists and engineering-geologists, a tentative evaluation of the volumes susceptible to be mobilized by instability processes acting on the surficial, weathered cover of the loose pyroclastics was performed, adopting different methodologies. The so obtained results are compared and discussed in the paper: overall, they provide evidence of a widespread proneness to slope instability, which in turn may result into a serious threat to the diffuse settlements and infrastructures located at the Camaldoli’s foothill.

Calcaterra, D.; Coppin, D.; Palma, B.; Parise, M.; Orsi, G.; de Vita, S.; di Vito, M. A.

2003-04-01

141

The geomorphology of Rhea - Implications for geologic history and surface processes  

NASA Technical Reports Server (NTRS)

Morphological analyses of landforms on Rhea are used to define three physiographic provinces: cratered terrain 1 undifferentiated; cratered terrain 1 lineated; and cratered terrain 2. The important statigraphic relationships between the different provinces are examined with respect to major impact basins and tectonic features. It is shown that the formation of multiringed basins may have caused, or at least controlled the locations of major resurfacing and mantling events. The diameters of the central peaks relative to the impact crater diameters are found to be significantly larger than those within the craters of the moon or Mercury. Both cratered and noncrater lineaments have regional orientations which do not fit current global or regional stress models. On the basis of the morphological analysis, a chronological order is established for the origin of the three provinces: the cratered terrain 1 province was formed first; and cratered terrain 1 lineated and cratered terrain 2 were formed second, and last, respectively. It is shown that the chronological order is generally consistent with current theoretical models of the evolution of Rhea.

Moore, J. M.; Horner, V. M.; Greeley, R.

1985-01-01

142

Geology of the region of Guadalajara, Mexico, and its relationships with processes of subsidence  

NASA Astrophysics Data System (ADS)

The city of Guadalajara, Mexico, began an accelerated urban growth in early 1950. During a span of 25 years a large number of gullies were artificially filled, with the aim of incorporating new areas for urbanization, particularly in the areas north and west of the city. These gullies originally formed a complex dendritic-type system, whose evolution may be associated with faults or fracture zones whose current identification are only possible based on escarpments along the Canyon of the Rio Grande de Santiago (CRGS), north of Guadalajara. Reports of affectations documented in the 80's described subsidence in buildings and infrastructure, a process that has been continued during 2008. We present the results of work done in the CRGS, which is a tectonic erosive-depression with an average depth of 500 m and exhibits a sequence of volcanic and sedimentary deposits with rapid lateral facies changes. The stratigraphic column spans a 15 km-long section along the Matatlán-Arcediano road, and, from top to bottom contains: 1) Unconsolidated pumice and tuffs with an average thickness of 12 m; 2) basaltic lavas with average thickness of 60 m; 3) the San Gaspar ignimbrite; 4) fluvial- sedimentary deposits with a thickness of approximately 20 meters that include both sub-rounded and angular volcanic clasts, with sizes up to 0.15 m; 5) a thick sequence of ignimbrites and dacitic lavas. At a depth of 1200 m.a.s.l. in the town of Arcediano, the basal sequence is composed of dacites and andesites with interbedded pumice-rich ignimbrites with 10-20 m thickness. The Rio Grande de Santiago talweg to 1018 m.a.s.l. (apparently the base of the sequence) is formed by andesite lava. In the area of San Gaspar we identified oblique-normal left-lateral faults in lavas, with a strike 191° and a dip 89°. In the Colimilla dam, 1297 m.a.s.l., we observed normal faulting (strike 267° and dip 81°), with 20-30 m jumps with reference to a unit of tephra of 3-10 m thickness. The lavas in this site present deformation, the main shear being parallel to the Rio Verde. At the site of the San Gaspar river the faults have a strike of 285° and a dip of 83v and affect ignimbrites that overlie dacitic lavas. In the area of the Arcediano bridge the normal faulting has a strike 188v and dip of 75° in andesites, and in the pumice-rich ignimbrites a shear direction with strike of 92° and dip of 84° that is parallel to the Rio Verde. During the past two years we identified approximately 1100 cases of sinking with varying magnitude in the urban area of Guadalajara. Some of these can be grouped to form alignments that are oriented with the faults identified in the CRGS region. The process of subsidence can be controlled by structures that affect the pumice sequence laying under the city of Guadalajara, facilitating the movement of groundwater through areas of weakness, removing tuffs and pumice and creating voids that later collapse, affecting buildings and infrastructure in the city.

Suarez-Plascencia, C.; Delgado-Argote, L. A.; Nuñez-Cornu, F. J.; Sanchez, J. J.

2008-12-01

143

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

144

GWM: A Ground-Water Management Process for the U.S. Geological Survey Modular Ground-Water Model (MODFLOW-2000).  

National Technical Information Service (NTIS)

GWM is a Ground-Water Management Process for the U.S. Geological Survey modular three-dimensional ground-water model, MODFLOW-2000. GWM uses a response-matrix approach to solve several types of linear, nonlinear, and mixed-binary linear ground-water manag...

D. P. Ahlfeld P. M. Barlow A. E. Mulligan

2005-01-01

145

Ecology of Caribbean Sponges: Are Top-Down or Bottom-Up Processes More Important?  

PubMed Central

Benthic-pelagic coupling and the role of bottom-up versus top-down processes are recognized as having a major impact on the structure of marine communities. While the roles of bottom-up processes are better appreciated they are still viewed as principally affecting the outcome of top-down processes. Sponges on coral reefs are important members of the benthic community and provide a critically important functional linkage between water-column productivity and the benthos. As active suspension feeders sponges utilize the abundant autotrophic and heterotrophic picoplankton in the water column. As a result sponges across the Caribbean basin exhibit a consistent and significant pattern of greater biomass, tube extension rate, and species numbers with increasing depth. Likewise, the abundance of their food supply also increases along a depth gradient. Using experimental manipulations it has recently been reported that predation is the primary determinant of sponge community structure. Here we provide data showing that the size and growth of the sponge Callyspongia vaginalis are significantly affected by food availability. Sponges increased in size and tube extension rate with increasing depth down to 46 m, while simultaneously exposed to the full range of potential spongivores at all depths. Additionally, we point out important flaws in the experimental design used to demonstrate the role of predation and suggest that a resolution of this important question will require well-controlled, multi-factorial experiments to examine the independent and interactive effects of predation and food abundance on the ecology of sponges.

Lesser, Michael P.; Slattery, Marc

2013-01-01

146

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

147

Self-Regulation Processes and Health: The Importance of Optimism and Goal Adjustment  

Microsoft Academic Search

This article discusses how self-regulatory models can be used to understand people's response to health threats. The article begins with a general discussion of the principles and assumptions of self-reg- ulatory models of behavior. Two distinct lines of research are then pre- sented addressing two important processes of adaptive self-regulation. First, we provide a brief overview of the literature on

Heather N. Rasmussen; Carsten Wrosch; Michael F. Scheier; Charles S. Carver

2006-01-01

148

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.

Langenheder, Silke; Szekely, Anna J

2011-01-01

149

How important is vehicle safety in the new vehicle purchase process?  

PubMed

Whilst there has been a significant increase in the amount of consumer interest in the safety performance of privately owned vehicles, the role that it plays in consumers' purchase decisions is poorly understood. The aims of the current study were to determine: how important vehicle safety is in the new vehicle purchase process; what importance consumers place on safety options/features relative to other convenience and comfort features, and how consumers conceptualise vehicle safety. In addition, the study aimed to investigate the key parameters associated with ranking 'vehicle safety' as the most important consideration in the new vehicle purchase. Participants recruited in Sweden and Spain completed a questionnaire about their new vehicle purchase. The findings from the questionnaire indicated that participants ranked safety-related factors (e.g., EuroNCAP (or other) safety ratings) as more important in the new vehicle purchase process than other vehicle factors (e.g., price, reliability etc.). Similarly, participants ranked safety-related features (e.g., advanced braking systems, front passenger airbags etc.) as more important than non-safety-related features (e.g., route navigation systems, air-conditioning etc.). Consistent with previous research, most participants equated vehicle safety with the presence of specific vehicle safety features or technologies rather than vehicle crash safety/test results or crashworthiness. The key parameters associated with ranking 'vehicle safety' as the most important consideration in the new vehicle purchase were: use of EuroNCAP, gender and education level, age, drivers' concern about crash involvement, first vehicle purchase, annual driving distance, person for whom the vehicle was purchased, and traffic infringement history. The findings from this study are important for policy makers, manufacturers and other stakeholders to assist in setting priorities with regard to the promotion and publicity of vehicle safety features for particular consumer groups (such as younger consumers) in order to increase their knowledge regarding vehicle safety and to encourage them to place highest priority on safety in the new vehicle purchase process. PMID:18460367

Koppel, Sjaanie; Charlton, Judith; Fildes, Brian; Fitzharris, Michael

2008-05-01

150

North Cascades Geology: Geologic Time  

NSDL National Science Digital Library

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

151

Geology of California. Second Edition  

SciTech Connect

Two introductory chapters familiarize readers with basic geologic concepts. The following chapters describe the geology of each of California's 11 geomorphic provinces; the San Andreas fault and offshore geology are discussed in two separate chapters. Four appendices acquaint readers with technical words and terms, common minerals and rocks in California, geologic time, and geologic theories that pertain to California. During the 1960s evidence collected from the east Pacific sea floor off the western coast of North America gave scientists supporting data for Alfred Wegener's 1910 theory of continental drift. In addition to the confirmation of continental drift, since the 1960s scientists have discovered paleomagnetism, sea-floor spreading, exotic and suspect terranes, and polar wandering. These important concepts have had far reaching effects about how we understand the geology of California and how this region has evolved through geologic time. Improved investigative procedures enable earth scientists to comprehend previously puzzling aspects of California's geology.

Norris, R.M.; Webb, R.W.

1990-01-01

152

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

153

Yosemite Geology  

NSDL National Science Digital Library

The National Park Service maintains the Yosemite National Park Web site and the corresponding Geology page. This Web site gives an overview of the geologic history of the site, tells how the Sierra Nevada range formed, explains the basics of granitic rock, shows how glaciers carved out the canyons, and much more.[JAB

154

Engineering Geology  

ERIC Educational Resources Information Center

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

Hatheway, Allen W.

1978-01-01

155

Geologic Time.  

ERIC Educational Resources Information Center

One of a series of general interest publications on science topics, the booklet provides those interested in geologic time with an introduction to the subject. Separate sections discuss the relative time scale, major divisions in geologic time, index fossils used as guides for telling the age of rocks, the atomic scale, and the age of the earth.…

Newman, William L.

156

Geologic processes in the RWMC area, Idaho National Engineering Laboratory: Implications for long term stability and soil erosion at the radioactive waste management complex  

SciTech Connect

The Radioactive Waste Management Complex (RWMC) is the disposal and storage facility for low-level radioactive waste at the Idaho National Engineering Laboratory (INEL). Transuranic waste and mixed wastes were also disposed at the RWMC until 1970. It is located in the southwestern part of the INEL about 80 km west of Idaho Falls, Idaho. The INEL occupies a portion of the Eastern Snake River Plain (ESRP), a low-relief, basalt, and sediment-floored basin within the northern Rocky Mountains and northeastern Basin and Range Province. It is a cool and semiarid, sagebrush steppe desert characterized by irregular, rolling terrain. The RWMC began disposal of INEL-generated wastes in 1952, and since 1954, wastes have been accepted from other Federal facilities. Much of the waste is buried in shallow trenches, pits, and soil vaults. Until about 1970, trenches and pits were excavated to the basalt surface, leaving no sediments between the waste and the top of the basalt. Since 1970, a layer of sediment (about 1 m) has been left between the waste and the basalt. The United States Department of Energy (DOE) has developed regulations specific to radioactive-waste disposal, including environmental standards and performance objectives. The regulation applicable to all DOE facilities is DOE Order 5820.2A (Radioactive Waste Management). An important consideration for the performance assessment of the RWMC is the long-term geomorphic stability of the site. Several investigators have identified geologic processes and events that could disrupt a radioactive waste disposal facility. Examples of these {open_quotes}geomorphic hazards{close_quotes} include changes in stream discharge, sediment load, and base level, which may result from climate change, tectonic processes, or magmatic processes. In the performance assessment, these hazards are incorporated into scenarios that may affect the future performance of the RWMC.

Hackett, W.R.; Tullis, J.A.; Smith, R.P. [and others

1995-09-01

157

The Martian Geomorphology as mapped by the Mars Express High Resolution Stereo Camera (HRSC): Implications for Geological Processes and Climate Conditions.  

NASA Astrophysics Data System (ADS)

One major reason for exploring Mars is the similarity of surface features to those present on Earth. Among the most important are morphological and mineralogical indicators that liquid water has existed on Mars at various locations over the entire history of the planet, albeit in decreasing abundance with time. Due to the strong evidence for aqueous processes at or near the surface, Mars is the most Earth-like body in the Solar System. The HRSC instrument is designed to simultaneously map the morphology, topography, structure and geologic context of the surface as well as atmospheric phenomena [1]. After 10 years of ESA's Mars Express orbiting the planet its High Resolution Stereo Camera (HRSC) has covered about 90 % of the surface in stereo and color with resolutions up to 10 m/pixel. Digital elevation models of up to 30-50 m grid spacing [1], generated from all suitable datasets of the stereo coverage, currently cover about 40% of the surface [1,2]. The geomorphological analyses of surface features, observed by the HRSC indicate major surface modifications by endogenic and exogenic processes at all scales. Endogenic landforms (e.g., tectonic rifts, small basaltic shield volcanoes) were found to be very similar to their equivalents on Earth [1,3,4,5,6,7]. Volcanism may have been active up to the very recent past or even to the present, putting important constraints on thermal evolution models [6,7]. The analysis of diverse landforms produced by aqueous processes revealed that surface water activity was likely episodic, but ranged in age from very ancient to very recent [1,8-16]. Particularly important are prominent glacial and periglacial features at several latitudes, including mountain glaciers and a frozen sea [17-21]. The identification of aqueous alteration minerals and their geological context has enabled a better understanding of paleoenvironmental conditions and pedogenetic processes [23-25]. Dark dunes contain volcanic material and are evidence for the very dynamic surface environment, characterized by widespread erosion, transport, and redeposition [26]. References: [1]Jaumann et al., 2007, PSS 55; [2]Gwinner et al., 2010, EPSL 294; [3]Neukum et al., 2004, Nature 432; [4]Neukum et al., EPSL 294;[5] Hauber et al., 2005, Nature 434; [6]Hauber et al., 2009 PSS 57; [7]Platz and Michael, 2011, EPSL 312, [8]Jaumann et al., 2005, GRL 32; [9]Jaumann et al., 2010, EPSL 294; [10]Erkeling et al., 2010, EPSL 294; [11]Erkeling et al., 2012, Icarus, 219; [12]Kleinhans et al., 2010, EPSL 294; [13]Reiss et al., 2009, PSS 57; [14]Kneissl et al., 2010, EPSL 294; [15]Di Achille et al., 2006, JGR 111; [16]Di Achille et al., 2006, GRL 33; [17]Head et al., 2005 Nature 434; [18]Murray et al., 2005 Nature 434; [19]Pacifici et al., 2009, Icarus 202; [20]Rossi et al., 2011, Geol. Soc. Am.356; [21]Marchant and Head, 2007, Icarus; [22]Ulrich et al., 2011 Geomorphology 134;[23] Le Deit et al., 2010, Icarus 208; [24]Le Deit et al., 2012, JGR 117; [25]Bishop et al., 2013, JGR 118; [26]Tirsch et al., 2011, JGR 116;

Jaumann, Ralf

2014-05-01

158

Fungal production of citric and oxalic acid: importance in metal speciation, physiology and biogeochemical processes.  

PubMed

The production of organic acids by fungi has profound implications for metal speciation, physiology and biogeochemical cycles. Biosynthesis of oxalic acid from glucose occurs by hydrolysis of oxaloacetate to oxalate and acetate catalysed by cytosolic oxaloacetase, whereas on citric acid, oxalate production occurs by means of glyoxylate oxidation. Citric acid is an intermediate in the tricarboxylic acid cycle, with metals greatly influencing biosynthesis: growth limiting concentrations of Mn, Fe and Zn are important for high yields. The metal-complexing properties of these organic acids assist both essential metal and anionic (e.g. phosphate) nutrition of fungi, other microbes and plants, and determine metal speciation and mobility in the environment, including transfer between terrestrial and aquatic habitats, biocorrosion and weathering. Metal solubilization processes are also of potential for metal recovery and reclamation from contaminated solid wastes, soils and low-grade ores. Such 'heterotrophic leaching' can occur by several mechanisms but organic acids occupy a central position in the overall process, supplying both protons and a metal-complexing organic acid anion. Most simple metal oxalates [except those of alkali metals, Fe(III) and Al] are sparingly soluble and precipitate as crystalline or amorphous solids. Calcium oxalate is the most important manifestation of this in the environment and, in a variety of crystalline structures, is ubiquitously associated with free-living, plant symbiotic and pathogenic fungi. The main forms are the monohydrate (whewellite) and the dihydrate (weddelite) and their formation is of significance in biomineralization, since they affect nutritional heterogeneity in soil, especially Ca, P, K and Al cycling. The formation of insoluble toxic metal oxalates, e.g. of Cu, may confer tolerance and ensure survival in contaminated environments. In semi-arid environments, calcium oxalate formation is important in the formation and alteration of terrestrial subsurface limestones. Oxalate also plays an important role in lignocellulose degradation and plant pathogenesis, affecting activities of key enzymes and metal oxido-reduction reactions, therefore underpinning one of the most fundamental roles of fungi in carbon cycling in the natural environment. This review discusses the physiology and chemistry of citric and oxalic acid production in fungi, the intimate association of these acids and processes with metal speciation, physiology and mobility, and their importance and involvement in key fungal-mediated processes, including lignocellulose degradation, plant pathogenesis and metal biogeochemistry. PMID:10500844

Gadd, G M

1999-01-01

159

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

Code of Federal Regulations, 2010 CFR

...the business of processing screenings who wishes to process screenings imported from Canada under...processing of otherwise prohibited screenings from Canada shall be a written...as to any material fact, a hearing shall be held to resolve...

2009-01-01

160

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

Code of Federal Regulations, 2010 CFR

...the business of processing screenings who wishes to process screenings imported from Canada under...processing of otherwise prohibited screenings from Canada shall be a written...as to any material fact, a hearing shall be held to resolve...

2010-01-01

161

faults role in geological processes. Repeated changing of activity mode and magnitude from basin formation to mountain belt staking: the case of the Sicilian Chain (Central Mediterranean)  

NASA Astrophysics Data System (ADS)

Faults reactivation (positive, oblique or negative inversions) often drives mountain building processes, from basin formation to accretionary wedge emplacement and its syn- and post-orogenic modifications. Several analytical studies on faults reactivation highlighted the importance of pre-existing fault orientation in the stress field, even though reactivation processes have only recently been considered as an important control in fault propagation. A better understanding of reactivation is essential to establish whether a fault is extinct or not, to better evaluate possible episodic fault activity and to determine the effects of reactivation on fault-growth behaviour and scaling relationships. Inherited normal faults pattern deriving from basin formation (i.e.: passive margin evolution), involved later in orogenic processes, may represents a constraint feature that controls the chain architecture and so the emplacement pattern and kinematic partition. In fact, these faults form zones of mechanical weakness that influence the architecture, kinematic pattern and distribution of crustal-scale deformation in both continental and oceanic regions. As long as a pre-existing fault remains mechanically weaker than its surroundings, strain is preferentially concentrated in the fault zone. This occurs, irrespective of whether the deformation is continuous or interrupted by periods of little activity, because pre-existing faults are surfaces along which the cohesive strength and the friction coefficient are lower than those of unfractured rock volumes. Otherwise, new-timed of thrust geometries firstly activated in convergent settings may act as a preferential strain partitioning zones during intra-collisional kinematic evolution processes driving the chain building, for example related to the mechanical status of the chain-foredeep-foreland system (i.e.: wedge subcritical, critical or supercritical stages). Multistep faults activities may be recognised through mesostructural analysis of master and minor faults populations recorded within the basin successions that experienced afterwards positive inversion to form thrust sheets in collisional-dominated settings. In Sicily (Central Mediterranean) a lot of pre-, syn- and post-orogenic brittle structures have been analysed. These faults have often recorded overprinted kinematic indicators, suggesting repeated interplay between extensional/oblique/compressional stress fields during geologic time. A comparison of structural and syn-deformational stratigraphic features allow us to recognise the palaeotectonic history of the Sicilian Chain and to hypothesise its kinematic evolution, from basin formation to the chain building and -earlier- chain modification of this segment of the Maghrebides African Margin. These faults experienced repeated changing of activity mode (positive and negative reactivations), magnitude and surface geometries, determining obstacles or preferential ways for strain partitioning, with regards to their size and orientation, during the syn- and post-orogenic processes.

Nigro, Fabrizio; Renda, Pietro; Favara, Rocco

2010-05-01

162

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

163

Laboratory Studies of Homogeneous and Heterogeneous Chemical Processes of Importance in the Upper Atmosphere  

NASA Technical Reports Server (NTRS)

The objective of this study was to conduct measurements of chemical kinetics parameters for reactions of importance in the stratosphere and upper troposphere, and to study the interaction of trace gases with ice surfaces in order to elucidate the mechanism of heterogeneous chlorine activation processes, using both a theoretical and an experimental approach. The measurements were carried out under temperature and pressure conditions covering those applicable to the stratosphere and upper troposphere. The main experimental technique employed was turbulent flow-chemical ionization mass spectrometry, which is particularly well suited for investigations of radical-radical reactions.

Molina, Mario J.

2003-01-01

164

Geology of Mars  

NSDL National Science Digital Library

This website provides information about the six geological processes that are either currently operating on Mars or have operated during Martian history. These include the aeolian, cratering, hydro, landslides, tectonic, and volcanic processes. Example images of the results of these processes are provided.

Hsui, Albert T.

2004-07-14

165

Process-orientated psychoanalytic work in initial interviews and the importance of the opening scene.  

PubMed

From the very first moment of the initial interview to the end of a long course of psychoanalysis, the unconscious exchange between analysand and analyst, and the analysis of the relationship between transference and countertransference, are at the heart of psychoanalytic work. Drawing on initial interviews with a psychosomatically and depressively ill student, a psychoanalytic understanding of initial encounters is worked out. The opening scene of the first interview already condenses the central psychopathology - a clinging to the primary object because it was never securely experienced as present by the patient. The author outlines the development of some psychoanalytic theories concerning the initial interview and demonstrates their specific importance as background knowledge for the clinical situation in the following domains: the 'diagnostic position', the 'therapeutic position', the 'opening scene', the 'countertransference' and the 'analyst's free-floating introspectiveness'. More recent investigations refer to 'process qualities' of the analytic relationship, such as 'synchronization' and 'self-efficacy'. The latter seeks to describe after how much time between the interview sessions constructive or destructive inner processes gain ground in the patient and what significance this may have for the decision about the treatment that follows. All these factors combined can lead to establishing a differential process-orientated indication that also takes account of the fact that being confronted with the fear of unconscious processes of exchange is specific to the psychoanalytic profession. PMID:24571347

Wegner, Peter

2014-06-01

166

Advances in Planetary Geology  

NASA Technical Reports Server (NTRS)

The surface of Mars displays a broad range of channel and valley features. There is as great a range in morphology as in scale. Some of the features of Martian geography are examined. Geomorphic mapping, crater counts on selected surfaces, and a detailed study of drainage basins are used to trace the geologic evolution of the Margaritifer Sinus Quandrangle. The layered deposits in the Valles Marineris are described in detail and the geologic processes that could have led to their formation are analyzed.

Grant, John A., III; Nedell, Susan S.

1987-01-01

167

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

168

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

169

Cruciform structures are a common DNA feature important for regulating biological processes.  

PubMed

DNA cruciforms play an important role in the regulation of natural processes involving DNA. These structures are formed by inverted repeats, and their stability is enhanced by DNA supercoiling. Cruciform structures are fundamentally important for a wide range of biological processes, including replication, regulation of gene expression, nucleosome structure and recombination. They also have been implicated in the evolution and development of diseases including cancer, Werner's syndrome and others.Cruciform structures are targets for many architectural and regulatory proteins, such as histones H1 and H5, topoisomerase II?, HMG proteins, HU, p53, the proto-oncogene protein DEK and others. A number of DNA-binding proteins, such as the HMGB-box family members, Rad54, BRCA1 protein, as well as PARP-1 polymerase, possess weak sequence specific DNA binding yet bind preferentially to cruciform structures. Some of these proteins are, in fact, capable of inducing the formation of cruciform structures upon DNA binding. In this article, we review the protein families that are involved in interacting with and regulating cruciform structures, including (a) the junction-resolving enzymes, (b) DNA repair proteins and transcription factors, (c) proteins involved in replication and (d) chromatin-associated proteins. The prevalence of cruciform structures and their roles in protein interactions, epigenetic regulation and the maintenance of cell homeostasis are also discussed. PMID:21816114

Brázda, Václav; Laister, Rob C; Jagelská, Eva B; Arrowsmith, Cheryl

2011-01-01

170

Pristine Noachian crust and key geologic transitions in the lower walls of Valles Marineris: Insights into early igneous processes on Mars  

NASA Astrophysics Data System (ADS)

Valles Marineris is a unique vertical section through the uppermost kilometers of the martian crust. Its location, east of the Tharsis bulge, and its water-related history, fuel a great diversity of rock types in this area (Carr, M.H., Head, J.W. [2010]. Earth Planet. Sci. Lett. 294, 185-203). HiRISE and CRISM data available over the walls of the canyon were analyzed to infer the importance of magmatic and sedimentary processes through time. This contribution provides a complete morphologic and mineralogic characterization of the cross-section of rocks exposed in the canyon walls. Low-calcium pyroxene and olivine are detected in the lower portion of the walls, in association with morphologically distinct outcrops, leading to the idea that pristine Noachian crust might be exposed. Phyllosilicates are also present within the walls, but they appear to correspond to an alteration product. No proper sedimentary layers were observed within the walls of Valles Marineris at the resolution available today. All these detections are limited to the eastern portion of Valles Marineris, especially Juventae, Coprates, Capri, and Ganges chasmata. Preserved Noachian crustal material is rare on the martian surface and is rarely exposed in its pristine geologic context. Such detections lend precious information about early igneous processes. This survey also supports observations from the nearby impact crater central peaks (Quantin, C., Flahaut, J., Allemand, P. [2009]. Lunar Planet. Sci. 10; Quantin, C., Flahaut, J., Clenet, H., Allemand, P., Thomas, P. [2011]. Icarus, submitted for publication) and suggests that the western part of Valles Marineris may be cut into another material, consistent with lavas or volcanic sediments.

Flahaut, Jessica; Quantin, Cathy; Clenet, Harold; Allemand, Pascal; Mustard, John F.; Thomas, Pierre

2012-09-01

171

Product or waste? Importation and end-of-life processing of computers in Peru.  

PubMed

This paper considers the importation of used personal computers (PCs) in Peru and domestic practices in their production, reuse, and end-of-life processing. The empirical pillars of this study are analysis of government data describing trade in used and new computers and surveys and interviews of computer sellers, refurbishers, and recyclers. The United States is the primary source of used PCs imported to Peru. Analysis of shipment value (as measured by trade statistics) shows that 87-88% of imported used computers had a price higher than the ideal recycle value of constituent materials. The official trade in end-of-life computers is thus driven by reuse as opposed to recycling. The domestic reverse supply chain of PCs is well developed with extensive collection, reuse, and recycling. Environmental problems identified include open burning of copper-bearing wires to remove insulation and landfilling of CRT glass. Distinct from informal recycling in China and India, printed circuit boards are usually not recycled domestically but exported to Europe for advanced recycling or to China for (presumably) informal recycling. It is notable that purely economic considerations lead to circuit boards being exported to Europe where environmental standards are stringent, presumably due to higher recovery of precious metals. PMID:19731711

Kahhat, Ramzy; Williams, Eric

2009-08-01

172

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

173

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

174

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

175

Importance of auroral features in the search for substorm onset processes  

NASA Astrophysics Data System (ADS)

Auroral features at about the onset time of substorms are revisited to emphasize their importance in considering substorm onset processes. This study is based on all-sky camera photographs and meridian scanning photometer records from a single station. First, in considering substorm onset processes, it is crucial to pay attention to the implication of the fact that an auroral arc located just poleward side of the initially brightening arc becomes active only after, not before, onset. Second, prior to substorm onset, there occurs a rapid equatorward shift, or more like narrowing the width, of the equatorward half of the oval, not the whole oval, without any distinct and immediate changes of the interplanetary magnetic field (IMF) Bz component, except that the shift tends to occur after the southward turning of the IMF. These phenomena suggest that some processes take place spontaneously at a distance of less than 10 RE, perhaps near the boundary between the central plasma sheet and the boundary plasma sheet, after the magnetosphere is primed by the IMF southward turning. Thus, it is concluded that substorm models in the near-Earth initiation category satisfy the observational constraints provided by the present paper. Because of our limited data set in terms of observations at single stations, new ground-based observations are suggested to confirm our results.

Akasofu, Syun-Ichi; Lui, A. T. Y.; Meng, C.-I.

2010-08-01

176

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

177

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

178

Side-scan sonar along the north wall of the Hess Deep Rift: Processing, texture analysis, and geologic ground truth on an oceanic escarpment  

NASA Astrophysics Data System (ADS)

Side-scan sonar data collected along the steep, faulted north wall of the Hess Deep Rift provide images of a cross section of the upper oceanic crust. These data are integrated with ground truth from the submersible Alvin and the Argo II remotely operated vehicle (ROV) to evaluate faulting and mass wasting associated with the opening of the rift and to help trace geologic contacts between widely spaced dives and ROV surveys. Initial shipboard and subsequently processed data show excellent backscatter returns with well-imaged textures and distinctive patterns corresponding to specific rock units and surficial deposits. Four backscatter textures are widely developed and found to correspond to outcrops of basaltic lavas, outcrops of sheeted dikes and gabbroic rocks, surficial talus and rubble deposits, and pelagic sedimentary material. Using test areas identified by Alvin dives, the side-scan sonar data were processed to automatically classify the backscatter returns in terms of major rock units. The resultant processed image is used for further manual and computer-aided classification of the scarp geology. These techniques are evaluated for mapping the geology in rugged terrains similar to the steep walls of Hess Deep Rift.

Hurst, Stephen D.; Karson, Jeffrey A.

2004-02-01

179

Geological Mediation of Hydrologic Process, Channel Morphology and Resultant Planform Response to Closure of Dwinnell Dam, Shasta River, California  

Microsoft Academic Search

Alluvial channel morphologies depend on hydrologic regime conditions defined by the magnitude, frequency, timing and variability of measured streamflows. Because regime conditions vary in part with the spatial distribution of underlying geology, the character of downstream channel form response to fluvial impoundment is mediated by not only changes to streamflow and sediment transport characteristics imparted by dam operations, but also

A. L. Nichols; J. F. Mount

2008-01-01

180

Geologic analyses of LANDSAT-1 multispectral imagery of a possible power plant site employing digital and analog image processing. [in Pennsylvania  

NASA Technical Reports Server (NTRS)

A site in the Great Valley subsection of the Valley and Ridge physiographic province in eastern Pennsylvania was studied to evaluate the use of digital and analog image processing for geologic investigations. Ground truth at the site was obtained by a field mapping program, a subsurface exploration investigation and a review of available published and unpublished literature. Remote sensing data were analyzed using standard manual techniques. LANDSAT-1 imagery was analyzed using digital image processing employing the multispectral Image 100 system and using analog color processing employing the VP-8 image analyzer. This study deals primarily with linears identified employing image processing and correlation of these linears with known structural features and with linears identified manual interpretation; and the identification of rock outcrops in areas of extensive vegetative cover employing image processing. The results of this study indicate that image processing can be a cost-effective tool for evaluating geologic and linear features for regional studies encompassing large areas such as for power plant siting. Digital image processing can be an effective tool for identifying rock outcrops in areas of heavy vegetative cover.

Lovegreen, J. R.; Prosser, W. J.; Millet, R. A.

1975-01-01

181

Raising the bar: the importance of hospital library standards in the continuing medical education accreditation process.  

PubMed

The Connecticut State Medical Society (CSMS) reviews and accredits the continuing medical education (CME) programs offered by Connecticut's hospitals. As part of the survey process, the CSMS assesses the quality of the hospitals' libraries. In 1987, the CSMS adopted the Medical Library Association's (MLA's) "Minimum Standards for Health Sciences Libraries in Hospitals." In 1990, professional librarians were added to the survey team and, later, to the CSMS CME Committee. Librarians participating in this effort are recruited from the membership of the Connecticut Association of Health Sciences Librarians (CAHSL). The positive results of having a qualified librarian on the survey team and the invaluable impact of adherence to the MLA standards are outlined. As a direct result of this process, hospitals throughout the state have added staffing, increased space, and added funding for resources during an era of cutbacks. Some hospital libraries have been able to maintain a healthy status quo, while others have had proposed cuts reconsidered by administrators for fear of losing valuable CME accreditation status. Creating a relationship with an accrediting agency is one method by which hospital librarians elsewhere may strengthen their efforts to ensure adequate library resources in an era of downsizing. In addition, this collaboration has provided a new and important role for librarians to play on an accreditation team. PMID:11465686

Gluck, J C; Hassig, R A

2001-07-01

182

Heterogeneous Ice Processes Important for Odd Hydrogen and Ozone on Mars  

NASA Astrophysics Data System (ADS)

Odd-hydrogen chemistry plays an important role in the ozone budget and the stabilization of carbon dioxide in the Martian atmosphere. In the lower atmosphere, heterogeneous processes influence the fate of odd-hydrogen species. The quantitative details of these heterogeneous physicochemical processes are poorly understood, leading to discrepancies between models and observations of the Martian atmosphere. Atmospheric models consistently underestimate the ozone abundances and overestimate the hydrogen peroxide densities. Heterogeneous loss of odd-hydrogen species has been suggested as a possible explanation. Relevant laboratory results are scarce in the literature, especially at the temperature range appropriate for the Martian atmosphere. We are conducting laboratory experiments to determine the uptake of various odd-hydrogen species by water ice and other substrates. We use a Knudsen cell apparatus, which is a low-pressure stirred-flow reactor in a configuration that allows heterogeneous uptake effects to be quantified by the change in the concentration of a gas phase species mixture flowing over a condensed matter substrate. We will present our recent results and discuss their relevance to the Martian odd-hydrogen and ozone chemistry. This material is based upon work supported by the National Aeronautics and Space Administration under Grant NNX10AM85G issued through the Mars Fundamental Research Program.

Kostko, O.; Marschall, J.; Kalogerakis, K.

2012-12-01

183

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

184

Accumulation of metals by microorganisms — processes and importance for soil systems  

NASA Astrophysics Data System (ADS)

Metal accumulation by solid substances can counteract metal mobilization in the environment if the solid substance is immobile. Microorganisms have a high surface area-to-volume ratio because of their small size and therefore provide a large contact area that can interact with metals in the surrounding environment. Microbial metal accumulation has received much attention in the last years due to the potential use of microorganisms for cleaning metal-polluted water. However, considerably less attention has been paid to the role of microorganisms for metal mobility in soil even though the same processes may occur there. Therefore, this paper highlights this area. The different accumulation processes that microorganisms perform are analyzed and their potential significance in soil systems is discussed. Different kinds of mechanisms can be involved in the accumulation of metals by microorganisms, e.g. adsorption, precipitation, complexation and active transport into the cell. Physicochemical parameters like pH and ionic composition, as well as biological factors are of importance for the magnitude of accumulation. Often large amounts of metals can be accumulated with varying specificity, and microorganisms may provide nucleation sites for mineral formation. Several studies of microbial metal accumulation have been made with different methods and aims. Most of these studies concern single-component systems with one organism at a time. Data from accumulation experiments with pure cultures of microorganisms have been used to model the overall metal retention in soil. A further development is experimental model systems using various solid soil components in salt medium. Microbial metal accumulation is difficult to study in situ, but some experimental methods have been applied as tools for studying real soil systems, e.g. litter bags buried in soil containing microorganisms, a method where discs with microorganisms have been put onto agar plates with soil extracts, and comparison of sterilized and non-sterilized soils or soils with or without nutrient amendment. Different aspects of microbial metal accumulation are emphasized with the different methods applied. Single-component systems have the advantage of providing excellent information of the metal binding properties of microorganisms but cannot directly be applied to metal behavior in the heterogenous systems that real soils constitute. Studies focused on the behavior of metals in real soils can, in contrast, provide information on the overall metal distribution but less insight into the processes involved. Obviously, a combination of approaches is needed to describe metal distribution and mobility in polluted soil such as areas around mines. Different kinds of multi-component systems as well as modelling may bridge the gap between these two types of studies. Several experimental methods, complementary to each other and designed to allow for comparison, may emphasize different aspects of metal accumulation and should therefore be considered. To summarize, there are studies that indicate that microorganisms may also accumulate metals in soil and that the amounts may be considerable. However, much work remains to be done, with the focus of microorganisms in soil. It is also important to put microbial metal accumulation in relation to other microbial processes in soil, which can influence metal mobility, to determine the overall influence of soil microorganisms on metal mobility, and to be able to quantify these processes.

Ledin, Maria

2000-08-01

185

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

Microsoft Academic Search

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

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

2009-01-01

186

Structural Geology  

NASA Astrophysics Data System (ADS)

Structural geology and continental tectonics were ushered in to the modern quantitative age of geosciences with the arrival of the global plate tectonics paradigm (circa 1968), derived using new data from the oceans' depths, and John Ramsay's 1967 seminal work, Folding and Fracturing of Rocks. Fossen is to be applauded for crafting a unique, high-caliber, and accessible undergraduate textbook on structural geology that faithfully reflects this advance and the subsequent evolution of the discipline. This well-written text draws on Fossen's wealth of professional experience, including his broad and diverse academic research and experience in the petroleum industry. This book is beautifully illustrated, with excellent original color diagrams and with impressive color field photographs that are all keyed to locations and placed into geologic context.

Weber, John; Frankel, Kurt L.

2011-05-01

187

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

188

Geologic Explorations  

NSDL National Science Digital Library

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

Bodzin, Alec M.

2001-01-01

189

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

Code of Federal Regulations, 2010 CFR

...persons generating PCBs in excluded manufacturing processes. 761.187 Section 761... POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING, DISTRIBUTION IN COMMERCE...persons generating PCBs in excluded manufacturing processes. In addition to...

2009-07-01

190

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

Code of Federal Regulations, 2010 CFR

...persons generating PCBs in excluded manufacturing processes. 761.187 Section 761... POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING, DISTRIBUTION IN COMMERCE...persons generating PCBs in excluded manufacturing processes. In addition to...

2010-07-01

191

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

Code of Federal Regulations, 2013 CFR

...persons generating PCBs in excluded manufacturing processes. 761.187 Section 761... POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING, DISTRIBUTION IN COMMERCE...persons generating PCBs in excluded manufacturing processes. In addition to...

2013-07-01

192

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

Code of Federal Regulations, 2010 CFR

...tobacco products, cigarette papers and tubes, and processed tobacco. 41.1 Section...TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND PROCESSED TOBACCO Scope of Regulations...tobacco products, cigarette papers and tubes, and processed tobacco. This...

2010-04-01

193

Spatial distribution of seafloor bio-geological and geochemical processes as proxies of fluid flux regime and evolution of a carbonate/hydrates mound, northern Gulf of Mexico  

NASA Astrophysics Data System (ADS)

Woolsey Mound, a carbonate/hydrate complex of cold seeps, vents, and seafloor pockmarks in Mississippi Canyon Block 118, is the site of the Gulf of Mexico Hydrates Research Consortium's (GOMHRC) multi-sensor, multi-disciplinary, permanent seafloor observatory. In preparation for installing the observatory, the site has been studied through geophysical, biological, geological, and geochemical surveys. By integrating high-resolution, swath bathymetry, acoustic imagery, seafloor video, and shallow geological samples in a morpho-bio-geological model, we have identified a complex mound structure consisting of three main crater complexes: southeast, northwest, and southwest. Each crater complex is associated with a distinct fault. The crater complexes exhibit differences in morphology, bathymetric relief, exposed hydrates, fluid venting, sediment accumulation rates, sediment diagenesis, and biological community patterns. Spatial distribution of these attributes suggests that the complexes represent three different fluid flux regimes: the southeast complex seems to be an extinct or quiescent vent; the northwest complex exhibits young, vigorous activity; and the southwest complex is a mature, fully open vent. Geochemical evidence from pore-water gradients corroborates this model suggesting that upward fluid flux waxes and wanes over time and that microbial activity is sensitive to such change. Sulfate and methane concentrations show that microbial activity is patchy in distribution and is typically higher within the northwest and southwest complexes, but is diminished significantly over the southeast complex. Biological community composition corroborates the presence of distinct conditions at the three crater complexes. The fact that three different fluid flux regimes coexist within a single mound complex confirms the dynamic nature of the plumbing system that discharges gases into bottom water. Furthermore, the spatial distribution of bio-geological processes appears to be a valid indicator of multiple fluid flux regimes that coexist at the mound.

Macelloni, Leonardo; Brunner, Charlotte A.; Caruso, Simona; Lutken, Carol B.; D'Emidio, Marco; Lapham, Laura L.

2013-04-01

194

Geology Fieldnotes  

NSDL National Science Digital Library

This National Park Service (NPS) site delivers a brief description of the geology of the Black Hills National Park. Links to park maps, a photo album, books, videos, CDs, and a searchable data base of research needs that have been identified by the National Park Service are included. General information about the park's education and interpretive programs are also abailable.

National Park Services (NPS)

195

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.

196

Geologic Time.  

ERIC Educational Resources Information Center

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

Albritton, Claude C., Jr.

1984-01-01

197

The preparation of illustrations for reports of the United States Geological survey : with brief descriptions of processes of reproduction  

USGS Publications Warehouse

There has been an obvious need in the Geological Survey o£ a paper devoted wholly to illustrations. No complete paper on the character, use, and mode of preparation of illustration has been published by the Survey, though brief suggestions concerning certain features of their use have been printed in connection wit other suggestions pertaining to publications. The present paper includes matter which it is hoped will be of service to authors in their work of making up original drafts of illustrations and to drafsmen who are using these originals in preparing more finished drawing but it is not a technical treatise on drafting.

Ridgway, John L.

1920-01-01

198

Biologic and geologic responses to physical processes: examples from modern reef systems of the Caribbean-Atlantic region  

NASA Astrophysics Data System (ADS)

Coral reefs and associated depositional environments of the Caribbean-Atlantic region have characteristics that reflect control by physical processes, both oceanic and atmospheric. Wave direction and wave power help determine sites for productive reef development and shape reef morphology as well as community structure. Spur and groove orientations reflect changes in direction of waves as they refract across a reef-dominated shelf. Abrupt topography of reef-dominated shelf margins interacts with tidally modulated flows to create an energetic and productive deep reef environment which is buffered from the modifying effects of forceful wave action. Shallow wave-reef interactions involve dissipative effects of wave breaking, turbulence, and friction, resulting in measured wave energy transformations ranging from 72 to 97% depending on reef configuration and water depth. Dissipative processes produce strong reef-normal surge currents that transport sediment lagoonward, drive backreef lagoon circulation, and influence fluid flow and diagenesis within the reef. The intensity of these processes is modulated at the tidal frequency. Other long period waves (infragravity) are important agents of mass transport of water and fine sediment. Low speed, long duration currents forced by long waves are potentially important for transporting larvae as well as fine sediment out of a given reef-lagoon system. Ocean-scale currents impinging on steep island and continental margin topography may cause reef-limiting upwelling and nutrient loading. The Caribbean Current upwells on the Nicaragua shelf and carbonate platforms of the Nicaraguan Rise. High trophic resources favor algal rather than coral communities and large (20-30 m relief) Halimeda biotherms occupy niches normally reserved for coral reefs. Thermodynamic air-sea interactions (heat, moisture and momentum flux) regulate the physical properties of reef lagoon and bank top waters. In extra-tropical reef settings (e.g. Bermuda, Florida, Bahamas and Arabian Gulf) cold air outbreaks cause precipitous drops in bank water temperatures and significant increases in bank water salinity and suspended sediment load. Water temperatures are routinely forced below the limit for survival of reef corals and many species of calcareous green algae. Associated increases in the density of shallow waters produce a disequilibrium with surface waters of the adjacent ocean favoring shelf transport to deep water sites of reef development and beyond.

Roberts, Harry H.; Wilson, Paul A.; Lugo-Fernández, Alexis

1992-07-01

199

Demonstrating the Importance of `` Good" Models of Land Surface Hydrological Processes  

NASA Astrophysics Data System (ADS)

To reduce the uncertainty in the prediction of land surface climates,, the Atmospheric Model Intercomparison Project (AMIP) Diagnostic Subproject 12 (DSP 12) and the Project for Intercomparison of Land-surface Parameterisation Schemes (PILPS) have analysed dependence of climate simulations on the land-surface schemes (LSSs). This analysis has comprised three efforts: (i) proving that LSSs matter in coupled simulations; (ii) investigating whether improvements in LSSs have occurred over time; and (iii) searching for novel means of validating LSS predictions. In the first, Irannejad et al. (2003) introduce a novel method for evaluating the dependence of 19 AMIP AGCMs' LH on the LSS by excluding the impact of the atmosphere. Pseudo LSSs (PLSSs) for LH in the form of multi-variable linear models expressing mean monthly LH as a function of atmospheric forcing are developed. Analysis over three large and climatically diverse river basins shows estimates of mean annual LH from the PLSSs agreeing well with the AGCMs' simulations. RMS errors range from 0.4 to 2.2 W m-2 depending on the region and the AGCM. When the PLSSs are driven by single atmospheric forcings, different LSSs behave differently, and the variability of mean annual LH among AGCMs increases. The second strand of our investigation uncovered a clear generational sequence of land-surface schemes: first generation 'no canopy'; second generation ` SiBlings'; and ` recent schemes'. We conclude that although continental surface modelling has improved over the last 30 years, full confidence remains elusive, in part due to tuning to available observations. Finally, we show that stable water isotopes challenge predictions of evaporation and condensation processes. These three-pronged findings prove that LSSs are important to AGCM and coupled climate predictions; demonstrate that new, or changed, land-surface components increase diversity among simulations; underline the need for validation data and also challenge current parameterisations with novel observations.

Pitman, A.; Irannejad, P.; McGuffie, K.; Henderson-Sellers, A.

2003-12-01

200

Processing of the glycosomal matrix-protein import receptor PEX5 of Trypanosoma brucei  

SciTech Connect

Highlights: ? Most eukaryotic cells have a single gene for the peroxin PEX5. ? PEX5 is sensitive to in vitro proteolysis in distantly related organisms. ? TbPEX5 undergoes N-terminal truncation in vitro and possibly in vivo. ? Truncated TbPEX5 is still capable of binding PTS1-containing proteins. ? PEX5 truncation is physiologically relevant or an evolutionary conserved artifact. -- Abstract: Glycolysis in kinetoplastid protists such as Trypanosoma brucei is compartmentalized in peroxisome-like organelles called glycosomes. Glycosomal matrix-protein import involves a cytosolic receptor, PEX5, which recognizes the peroxisomal-targeting signal type 1 (PTS1) present at the C-terminus of the majority of matrix proteins. PEX5 appears generally susceptible to in vitro proteolytic processing. On western blots of T. brucei, two PEX5 forms are detected with apparent M{sub r} of 100 kDa and 72 kDa. 5?-RACE-PCR showed that TbPEX5 is encoded by a unique transcript that can be translated into a protein of maximally 72 kDa. However, recombinant PEX5 migrates aberrantly in SDS–PAGE with an apparent M{sub r} of 100 kDa, similarly as observed for the native peroxin. In vitro protease susceptibility analysis of native and {sup 35}S-labelled PEX5 showed truncation of the 100 kDa form at the N-terminal side by unknown parasite proteases, giving rise to the 72 kDa form which remains functional for PTS1 binding. The relevance of these observations is discussed.

Gualdrón-López, Melisa [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium)] [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium); Michels, Paul A.M., E-mail: paul.michels@uclouvain.be [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium)

2013-02-01

201

Use of Library Readings to Augment Conventional Geology Instruction.  

ERIC Educational Resources Information Center

Examples of sets of questions on library readings designed to lead students into articles and emphasize important information and associated literature are presented for introductory geology courses, historical geology, structural geology, mineralogy, and petrology. (Author/CW)

Nold, John Lloyd

1989-01-01

202

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

203

Sedimentologic relevance of convulsive geologic events  

SciTech Connect

Convulsive (or catastrophic) geologic events undeniably have been part of the history of our planet throughout geologic time. Convulsive events are violent disturbances of regional or even global extent. Some types, such as giant storms or explosive volcanic eruptions, are commonplace in the geologic record; others, such as major bolide impact, are exceedingly rare. The sedimentologic record of convulsive geologic events differs in preservation potential depending largely on whether the effect occurs within an active depositional basin. In some settings, such as deep sea fans, a significant part of the deposit may result from large and violent events. The record within the sediment of a convulsive event may be either dramatic or subtle; the degree of distinctiveness therein may not be an accurate guide to the overall consequence of the event on a accurate guide to the overall consequence of the event on a planetary scale. Because convulsive events typically produce a brief, but significant, disturbance over a broad area, their sedimentologic consequences provide excellent chronologic markers in the stratigraphic record, in some cases on a global scale. Perhaps most importantly, the recognition of the results of convulsive events in the geologic record forces one to consider processes operating at a scale that may be inconceivable in the context of our present-day world.

Clifton, H.E.

1985-01-01

204

Geology of Mojave National Preserve  

NSDL National Science Digital Library

This website of the United States Geological Survey (USGS) and the National Park Service (NPS) highlights the geology of the Mojave National Preserve in California. It includes a field trip describing areas of interest at the preserve, as well as a geologic time scale describing the history and development of this area. Processes that shaped this region include volcanism, tectonics, faulting, erosion, deposition, spreading, intrusions, and glaciation. There is a geologic map of the area with units and a legend, and links to maps and technical papers.

205

The geology of Venus  

NASA Astrophysics Data System (ADS)

This paper summarizes the emerging picture of the surface of Venus provided by high-resolution earth-based radar telescopes and orbital radar altimetry and imaging systems. The nature and significance of the geological processes operating there are considered. The types of information needed to complete the picture are addressed.

Basilevsky, A. T.; Head, J. W.

206

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

207

Status report on the geology of the Oak Ridge Reservation  

SciTech Connect

This report provides an introduction to the present state of knowledge of the geology of the Oak Ridge Reservation (ORR) and a cursory introduction to the hydrogeology. An important element of this work is the construction of a modern detailed geologic map of the ORR (Plate 1), which remains in progress. An understanding of the geologic framework of the ORR is essential to many current and proposed activities related to land-use planning, waste management, environmental restoration, and waste remediation. Therefore, this report is also intended to convey the present state of knowledge of the geologic and geohydrologic framework of the ORR and vicinity and to present some of the available data that provide the basic framework for additional geologic mapping, subsurface geologic, and geohydrologic studies. In addition, some recently completed, detailed work on soils and other surficial materials is included because of the close relationships to bedrock geology and the need to recognize the weathered products of bedrock units. Weathering processes also have some influence on hydrologic systems and processes at depth.

Hatcher, R.D. Jr.; Lemiszki, P.J.; Foreman, J.L. (Tennessee Univ., Knoxville, TN (United States). Dept. of Geological Sciences); Dreier, R.B.; Ketelle, R.H.; Lee, R.R.; Lee, Suk Young (Oak Ridge National Lab., TN (United States)); Lietzke, D.A. (Lietzke (David A.), Rutledge, TN (United States)); McMaster, W.M. (McMaster (William M.), Heiskell, TN (United States))

1992-10-01

208

Geology Fulbrights  

NASA Astrophysics Data System (ADS)

Fulbright grants in geology for 1988-89 remain open. Specific opportunities are available in Egypt, German Democratic Republic, Hungary, Iceland, Iraq, Kuwait, Morocco, Mozambique, Oman, Poland, Sudan, Syria, Tanzania, Turkey, U.S.S.R., West Bank, Yemen, and Zimbabwe. Other countries are also open to applications in any discipline, and geology is among their preferred fields.The grants are available until awarded and are open only to U.S. citizens. In Central and South America and French-speaking Africa, knowledge of host-country language is required. For more information, contact the Council for International Exchange of Scholars (CIES), 11 Dupont Circle N.W., Suite 300, Washington, DC 20036; tel. 202-939-5401.

209

Project Earth Science: Geology  

NSDL National Science Digital Library

Now you can literally explain what it's like "between a rock and a hard place!" Use Project Earth Science: Geology to introduce your students to plate tectonics and teach them what causes volcanoes and earthquakes. Lead explorations of these and other larger-than-the-classroom geological phenomena with the teacher-tested, Standards -based activities. Earth's physical evolution and dynamic processes are carefully explained in language accessible to students and teachers. Supplemental readings provide educators with the background information to answer student questions and concerns.

Ford, Brent A.

2001-01-01

210

Physical Geology  

NSDL National Science Digital Library

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

Nelson, Stephen

211

Terrestrial analogs, planetary geology, and the nature of geological reasoning  

NASA Astrophysics Data System (ADS)

Analogical reasoning is critical to planetary geology, but its role can be misconstrued by those unfamiliar with the practice of that science. The methodological importance of analogy to geology lies in the formulation of genetic hypotheses, an absolutely essential component of geological reasoning that was either ignored or denigrated by most 20th century philosophers of science, who took the theoretical/ experimental methodology of physics to be the sole model for all of scientific inquiry. Following the seminal 19th century work of Grove Karl Gilbert, an early pioneer of planetary geology, it has long been recognized that broad experience with and understanding of terrestrial geological phenomena provide geologists with their most effective resource for the invention of potentially fruitful, working hypotheses. The actions of (1) forming such hypotheses, (2) following their consequences, and (3) testing those consequences comprise integral parts of effective geological practice in regard to the understanding of planetary surfaces. Nevertheless, the logical terminology and philosophical bases for such practice will be unfamiliar to most planetary scientists, both geologists and nongeologists. The invention of geological hypotheses involves both inductive inferences of the type Gilbert termed “empiric classification” and abductive inferences of a logical form made famous by the 19th century American logician Charles Sanders Peirce. The testing and corroboration of geological hypotheses relies less on the correspondence logic of theoretical/ experimental sciences, like physics, and more on the logic of consistency, coherence, and consilience that characterizes the investigative and historical sciences of interpretation exemplified by geology.

Baker, Victor R.

2014-05-01

212

Geologic Evolution of Eastern Hellas, Mars: Styles and Timing of Volatile-driven Activity  

NASA Technical Reports Server (NTRS)

The east rim of the Hellas basin and the surrounding highlands comprise a geologically significant region for evaluating volatile abundance, volatile distribution and cycling, and potential changes in Martian environmental conditions. This region of the Martian surface exhibits landforms shaped by a diversity of geologic processes and has a well-preserved geologic record, with exposures of Noachian, Hesperian, and Amazonian units, as well as spans a wide range in both latitude and elevation due to the magnitude of Hellas basin. In addition, geologically contemporaneous volcanism and volatile-driven activity in the circum-Hellas highlands provide important ingredients for creating habitats for potential Martian life.

Crown, David A.; Bleamaster, Leslie F., III; Mest, Scott C.

2004-01-01

213

The Importance of Rapid Auditory Processing Abilities to Early Language Development: Evidence from Converging Methodologies  

PubMed Central

The ability to process two or more rapidly presented, successive, auditory stimuli is believed to underlie successful language acquisition. Likewise, deficits in rapid auditory processing of both verbal and nonverbal stimuli are characteristic of individuals with developmental language disorders such as Specific Language Impairment. Auditory processing abilities are well developed in infancy, and thus such deficits should be detectable in infants. In the studies presented here, converging methodologies are used to examine such abilities in infants with and without a family history of language disorder. Behavioral measures, including assessments of infant information processing, and an EEG/event-related potential (ERP) paradigm are used concurrently. Results suggest that rapid auditory processing skills differ as a function of family history and are predictive of later language outcome. Further, these paradigms may prove to be sensitive tools for identifying children with poor processing skills in infancy and thus at a higher risk for developing a language disorder.

Thomas, Jennifer J.; Choudhury, Naseem; Leppanen, Paavo H. T.

2006-01-01

214

Thermohydrology of fractured geologic materials  

NASA Astrophysics Data System (ADS)

Thermohydrological and thermohydrochemical modeling as applied to the disposal of radioactive materials in a geologic repository is presented. Site hydrology, chemistry, and mineralogy were summarized and conceptual models of the fundamental system processes were developed. The numerical model TOUGH2 was used to complete computer simulations of thermohydrological processes in fractured, geologic media. Sensitivity studies investigating the impact of dimensionality and different conceptual models to represent fractures (ECM, DK, MINC) on thermohydrological response were developed. Sensitivity to parameter variation within a given conceptual model was also considered. The sensitivity of response was examined against thermohydrological metrics derived from the flow and redistribution of moisture. A simple thermohydrochemical model to investigate a three-process coupling (thermal-hydrological-chemical) was presented. The redistribution of chloride was evaluated because the chemical behavior is well known and defensible. In addition, it is very important to overall system performance. For all of the simulations completed, chloride was found to be extremely concentrated in the fluids that eventually return to the engineered barrier system. Chloride concentration and mass flux were increased from ambient by over a factor of 1000 for some simulations. Thermohydrology was found to have the potential to significantly alter chemistry from ambient conditions.

Esh, David Whittaker

1998-11-01

215

Helium studies in geology  

NASA Astrophysics Data System (ADS)

A special issue of the Journal of Geophysical Research—Solid Earth and Planets will be devoted to the topic "Helium Studies in Geology." Both helium isotopic research and helium 4 investigations on any phase of geologic application will be included. Individuals are welcome to submit manuscripts for this special issue. The deadline for receipt of papers through the normal JGR submission process is May 30, 1986. Please indicate that the manuscript is for the special issue. For additional information, contact G. M. Reimer, U.S. Geological Survey, MS 963, Denver Federal Center, Denver, CO 80225; telephone: 303236-7886 or JGR editor Gerald Schubert, Department of Earth and Space Sciences, University of California, Los Angeles, CA 90024; telephone: 213-82 5-4577.

216

NSF Awards 19 New Projects to Better Understand Genetic Processes in Plants of Economic Importance  

NSF Publications Database

... important crop plants such as wheat and soybeans as well as increase understanding of the genetic ... Los Angeles-led project focuses on the soybean to identify all of the genes and regulatory networks ...

217

The importance of the ammonia purification process in ammonia–water absorption systems  

Microsoft Academic Search

Practical experience in working with ammonia–water absorption systems shows that the ammonia purification process is a crucial issue in order to obtain an efficient and reliable system. In this paper, the detrimental effects of the residual water content in the vapour refrigerant are described and quantified based on the system design variables that determine the effectiveness of the purification process.

José Fernández-Seara; Jaime Sieres

2006-01-01

218

Characterizing Lunar Crustal Geology  

NASA Astrophysics Data System (ADS)

In our initiative to return to the Moon, knowledge of regional crustal geology is necessary both for locating resources of scientific interest and for establishing a sustained human presence. Characterizing crustal geology with global remote sensing data is difficult due to the types of weathering processes experienced by an airless, geologically torpid planetary body, which tend to reduce lithologic contrast and obscure the lithology of true bedrock. Fortunately, these processes are relatively straightforward, involving parameters with largely understood, fixed rates of flux. We describe a methodology for characterizing the chemical and mineralogical compositions of discrete geologic units, interpreted from remotely sensed surface spectra. The method utilizes two established techniques: small impact ejecta viewing and extrapolation (SIEVE) (McCord et al., JGR 1981; Staid & Pieters, LPSC 29; Kramer et al., LPSC 36; Kramer et al., JGR (in review)) and spectral mixing analysis (SMA) (Adams & Gillespie, Cambridge Univ. Press 2006, and references therein). The results of this work will be invaluable for identifying regions of interest for current and future lunar missions, such as Chandrayaan-1, carrying NASA's Moon Mineralogy Mapper, and Lunar Reconnaissance Orbiter. Furthermore, the methodology can be used to explore other planetary bodies that experience similar weathering processes (e.g., Mercury, Ceres, Vesta, and Mars).

Kramer, G.; Combe, J.; McCord, T.

2007-12-01

219

Relating Major Surface Processes to the Deep Earth — The Importance of the Miocene  

NASA Astrophysics Data System (ADS)

Many global scale tectonic, oceanic and climate changes began in the Tertiary with global tectonics as the underlying driving force and changed the world. In full flower by the beginning of the Middle Miocene around 16 Ma, these changes continued through the Late Miocene into the present so we can firmly say that most of our modern world, continental glaciations excepted, began in the Middle and Late Miocene. We summarize in a flow diagram how the major earth surface processes active in the Miocene are related to the Deep Earth as understood by recent advances in seismic tomography. This 11 Ma interval had two global orogenic zones, the Alpine-Tethyan orogen from Gibraltar across southern Asia into Vietnam and around the Pacific Rim, both crustal expressions of downwellings taking place, especially in the upper mantle. These downwellings are balanced by upwellings in the lower mantle in and on the rim of the African and Pacific superplumes, which are large, low-shear velocity provinces; part of the rising plumes originated from the most extensively melted regions of the core-mantle boundary layer, D", where heat flow from the outer core is highest. Together these up-and downwellings indicate that mantle convection extended, at least periodically, through the whole mantle and reflected lateral variations in convection and heat flow in the cooling and slowly crystallizing outer core. Correlation of mantle convection with surface features is most evident in the uppermost mantle whose dynamic topography is readily reflected by the subsidence and tilting of continents moving toward the downwelling zones. Because they are closely synchronous, these two orogenic belts had enormous consequences for the earth's surface, and because they are close to us in time, they are easy to study and sample. Thus the Miocene is ideal to study for both its many global intra connections and for their link to the Deep Earth. As these two orogenies developed, they changed a global warm water ocean into our present cooler, more fragmented system with a cooler atmosphere. Higher plateaus and uplifted mountains deflected jet streams, expanded rain shadows promoting desertification, favored initial mountain glaciation, and helped cool air temperatures. Upwelling was enhanced on both sides of the Pacific basin, silica production shifted from the Atlantic to the Pacific and Indian Oceans, more mud and sand were brought to the ocean causing many passive margins to prograde, and hemipelagic mud became more abundant off continental margins. At the very end of the Miocene even the Mediterranean dried up, as it was isolated by the Alpine orogeny at Gibraltar. Onshore, epeirogenic uplift was widespread both in the interiors of the continents and along many of their margins. Active convergent margins changed continental tilts, completely altered some rivers, and formed new ones with new deltas, some on the other side of a continent. The above changes greatly altered the surface environment and induced many significant changes in flora and fauna and their distribution and have great economic importance. Many of the major geochemical cycles of the ocean and atmosphere also experienced major changes at this time. We posit that the generalizations ultimately emerging from the Miocene will apply to all the Phanerozoic and far back into the Precambrian and that are all tied to Deep Earth.

Potter, P. E.; Szatmari, P.

2012-12-01

220

R&D Continues to be an Important Part of the Innovation Process  

NSF Publications Database

... Process innovation appears as prevalent as product innovation. R&D is performed by 84 percent of ... product quality, increase or maintain market share, and extend product range within main product ...

221

Theoretical Study of Laser-Stimulated Chemical Vapor Deposition Processes of Importance in Microelectronics.  

National Technical Information Service (NTIS)

Recent experiments have demonstrated that laser radiation incident on a gas surface interface can stimulate and control the process of vapor deposition onto the surface. This research project has been a theoretical analysis of the deposition and related l...

T. F. George

1983-01-01

222

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

223

[Processing, targeting and import into the mitochondria and peroxisomes of proteins coded by nuclear genes].  

PubMed

I have herein discussed two gene-enzyme families in maize whose protein products participate to purge toxic oxidants from cells, and are thus of importance to all aerobic organisms. We have demonstrated that plant mitochondria import precursor proteins (i.e., preSOD-3) in a manner analogous to other eukaryotic cells. The "transit peptide" (TP) of preSOD-3 is 31 amino acid long and has similar properties to other reported TPs for mitochondrial and chloroplastic proteins. Import to peroxisomes is uniquely different from that for mitochondria and chloroplasts in that no consensus presequence seems to be involved. Instead, targeting signals seem to be integral parts of peroxisomal proteins. PMID:1294925

Scandalios, J G

1992-01-01

224

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.

225

A signal sequence domain essential for processing, but not import, of mitochondrial pre-ornithine carbamyl transferase.  

PubMed

Studies using deletion mutagenesis indicate that a processing recognition site lies proximal to the normal cleavage position between gln32 and ser33 of pre-ornithine carbamyl transferase (pOCT). pOCT cDNA was manipulated to delete codons specifying amino acids 22-30 of the signal sequence. The mutant precursor, designated pOCT delta 22-30, was imported to the matrix compartment by purified mitochondria, but remained largely unprocessed; the low level of processing that was observed did not involve the normal cleavage site. Several manipulations performed downstream of the normal pOCT processing site (deletion, substitution, and hybrid protein constructions) affected neither import nor correct processing. Our data suggest that domains specifying import and processing site recognition may be functionally segregated within the signal peptide; that processing is not requisite for import of pOCT; and that a proximal region, not involving the normal signal peptide cleavage site, is required for processing site recognition. PMID:3571328

Nguyen, M; Argan, C; Sheffield, W P; Bell, A W; Shields, D; Shore, G C

1987-05-01

226

Miscellaneous and Processed Products: Regulating the Importation of Miscellaneous and Processed Products Regulated by Plant Protection and Quarantine (03/2010-06).  

National Technical Information Service (NTIS)

The Miscellaneous and Processed Products Manual provides the background, procedures, and reference tables for regulating imported articles of nonplant origin (i.e., goatskins, brassware, and beeswax) that might serve to introduce exotic pests and parasite...

2010-01-01

227

Assignments: An Important Means of Learning Subject Matter and the Writing Process.  

ERIC Educational Resources Information Center

Presents assignments as an important mechanism for developing writing skills and for learning about science. Describes a teaching strategy that allows a student's writing skills to develop while researching a particular science topic. Discusses topic selection, collection of information, drafting, and editing. (18 references) (JRH)

Havel, P. D.

1995-01-01

228

Influence of introgression and geological processes on phylogenetic relationships of Western North American mountain suckers (Pantosteus, Catostomidae).  

PubMed

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

229

A Comparison of Multivariate and Pre-Processing Methods for Quantitative Laser-Induced Breakdown Spectroscopy of Geologic Samples  

NASA Technical Reports Server (NTRS)

The ChemCam instrument selected for the Curiosity rover is capable of remote laser-induced breakdown spectroscopy (LIBS).[1] We used a remote LIBS instrument similar to ChemCam to analyze 197 geologic slab samples and 32 pressed-powder geostandards. The slab samples are well-characterized and have been used to validate the calibration of previous instruments on Mars missions, including CRISM [2], OMEGA [3], the MER Pancam [4], Mini-TES [5], and Moessbauer [6] instruments and the Phoenix SSI [7]. The resulting dataset was used to compare multivariate methods for quantitative LIBS and to determine the effect of grain size on calculations. Three multivariate methods - partial least squares (PLS), multilayer perceptron artificial neural networks (MLP ANNs) and cascade correlation (CC) ANNs - were used to generate models and extract the quantitative composition of unknown samples. PLS can be used to predict one element (PLS1) or multiple elements (PLS2) at a time, as can the neural network methods. Although MLP and CC ANNs were successful in some cases, PLS generally produced the most accurate and precise results.

Anderson, R. B.; Morris, R. V.; Clegg, S. M.; Bell, J. F., III; Humphries, S. D.; Wiens, R. C.

2011-01-01

230

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.

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

2014-01-01

231

Integration of the first and second generation bioethanol processes and the importance of by-products.  

PubMed

Lignocellulosic ethanol has obstacles in the investment costs and uncertainties in the process. One solution is to integrate it with the running dry mills of ethanol from grains. However, the economy of these mills, which dominate the world market, are dependent on their by-products DDGS (Distiller's Dried Grains and Solubles), sold as animal feed. The quality of DDGS therefore must not be negatively influenced by the integration. This puts restraints on the choice of pretreatment of lignocelluloses and utilizing the pentose sugars by food-grade microorganisms. The proposed solution is to use food related filamentous Zygomycetes and Ascomycetes fungi, and to produce fungal biomass as a high-grade animal feed from the residues after the distillation (stillage). This also has the potential to improve the first generation process by increasing the amount of the thin stillage directly sent back into the process, and by decreasing the evaporator based problems. PMID:24582951

Lennartsson, Patrik R; Erlandsson, Per; Taherzadeh, Mohammad J

2014-08-01

232

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

233

[Failure mechanisms in the transfusion process. Importance of anticipatory operational safety analysis].  

PubMed

The methods used for the safety previsional analysis of operations represent an interesting set of tools to follow the so-called transfusion process, defined as all the steps from donors sensitization to recipients follow-up. FMECA (Failure Mode Effects and Criticality Analysis) can be used as a prevention tool, independently of any dysfunction in the process. Of course, it can also be used following a failure, in order to analyse its causes and to apply specific corrections. Operation safety, quality insurance, epidemiologic surveillance and safety monitoring act in synergy. These three aspects of transfusion safety constitute a dynamic system. PMID:7812465

Hergon, E; Crespeau, H; Rouger, P

1994-01-01

234

Triangular framework mesh generation of 3D geological structure  

NASA Astrophysics Data System (ADS)

The dynamic simulation of oil migration and accumulation is an important issue on the research of petroleum exploration, and it is a numerical simulation process with special requirement on the framework mesh of 3D geological models, which means that the mesh should have same geometry and topology relation near the intersected part of geological surfaces. In this paper, basing on the conforming Delaunay triangulation algorithm to construct mesh of individual geological stratum or fault, a novel link-Delaunay-triangulation method is presented to achieve the geometric and topological consistency in the intersected line between two surfaces, also with the analysis of termination of our algorithm. Finally, some examples of the geological framework mesh are provided and the experimental result proved that the algorithm's effectiveness in engineering practice.

Meng, Xianhai; Zhou, Kun; Li, Jigang; Yang, Qin

2013-03-01

235

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

236

Geologic Resource Evaluation of Kaloko-Honokohau National Historical Park, Hawaii; Geology and Coastal Landforms.  

National Technical Information Service (NTIS)

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 ...

A. E. Gibbs B. M. Richmond S. A. Cochran

2009-01-01

237

Chapter 4: Geological Carbon Sequestration.  

National Technical Information Service (NTIS)

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...

J. Friedmann H. Herzog

2006-01-01

238

Importance of deposition processes in simulating the seasonality of the Arctic black carbon aerosol  

Microsoft Academic Search

Anthropogenic aerosol components in the Arctic troposphere, such as black carbon (BC), show a strong seasonal variation characterized by a peak in later winter and early spring. The seasonality, however, is not properly simulated by most existing global aerosol models. Using the Canadian global air quality model with an online aerosol algorithm-Global Environmental Multiscale model with Air Quality processes (GEM-AQ),

L. Huang; S. L. Gong; C. Q. Jia; D. Lavoué

2010-01-01

239

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

240

78 FR 38555 - Importer Permit Requirements for Tobacco Products and Processed Tobacco, and Other Requirements...  

Federal Register 2010, 2011, 2012, 2013

...Products, Processed Tobacco, and Cigarette Papers and Tubes AGENCY: Alcohol and Tobacco...requirements for tobacco products and cigarette papers and tubes, and, as a result, these...pertaining to tobacco products and cigarette papers and tubes. Section 5701 of the...

2013-06-27

241

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

242

Examining the Institutional Transformation Process: The Importance of Sensemaking, Interrelated Strategies, and Balance.  

ERIC Educational Resources Information Center

Developed elements of a transformational change framework through case studies of 6 institutions over a 4-year period. Three key findings were: (1) five core strategies for transformational change; (2) the characteristic that makes them essential: sensemaking; and (3) the interrelationship among core and secondary strategies, the nonlinear process…

Kezar, Adrianna; Eckel, Peter

2002-01-01

243

Shell biofilm-associated nitrous oxide production in marine molluscs: processes, precursors and relative importance.  

PubMed

Emission of the greenhouse gas nitrous oxide (N2 O) from freshwater and terrestrial invertebrates has exclusively been ascribed to N2 O production by ingested denitrifying bacteria in the anoxic gut of the animals. Our study of marine molluscs now shows that also microbial biofilms on shell surfaces are important sites of N2 O production. The shell biofilms of Mytilus edulis, Littorina littorea and Hinia reticulata contributed 18-94% to the total animal-associated N2 O emission. Nitrification and denitrification were equally important sources of N2 O in shell biofilms as revealed by (15) N-stable isotope experiments with dissected shells. Microsensor measurements confirmed that both nitrification and denitrification can occur in shell biofilms due to a heterogeneous oxygen distribution. Accordingly, ammonium, nitrite and nitrate were important drivers of N2 O production in the shell biofilm of the three mollusc species. Ammonium excretion by the animals was found to be sufficient to sustain N2 O production in the shell biofilm. Apparently, the animals provide a nutrient-enriched microenvironment that stimulates growth and N2 O production of the shell biofilm. This animal-induced stimulation was demonstrated in a long-term microcosm experiment with the snail H.?reticulata, where shell biofilms exhibited the highest N2 O emission rates when the animal was still living inside the shell. PMID:22830624

Heisterkamp, Ines M; Schramm, Andreas; Larsen, Lone H; Svenningsen, Nanna B; Lavik, Gaute; de Beer, Dirk; Stief, Peter

2013-07-01

244

Novice to Expert Cognition During Geologic Bedrock Mapping  

NASA Astrophysics Data System (ADS)

Bedrock geologic mapping is a complex and cognitively demanding task. Successful mapping requires domain-specific content knowledge, visuospatial ability, navigation through the field area, creating a mental model of the geology that is consistent with field data, and metacognition. Most post-secondary geology students in the United States receive training in geologic mapping, however, not much is known about the cognitive processes that underlie successful bedrock mapping, or about how these processes change with education and experience. To better understand cognition during geologic mapping, we conducted a 2-year research study in which 67 volunteers representing a range from undergraduate sophomore to 20+ years professional experience completed a suite of cognitive measures plus a 1-day bedrock mapping task in the Rocky Mountains, Montana, USA. In addition to participants' geologic maps and field notes, the cognitive suite included tests and questionnaires designed to measure: (1) prior geologic experience, via a self-report survey; (2) geologic content knowledge, via a modified version of the Geoscience Concept Inventory; (3) visuospatial ability, working memory capacity, and perceptual speed, via paper-and-pencil and computerized tests; (4) use of space and time during mapping via GPS tracking; and (5) problem-solving in the field via think-aloud audio logs during mapping and post-mapping semi-structured interviews. Data were examined for correlations between performance on the mapping task and other measures. We found that both geological knowledge and spatial visualization ability correlated positively with accuracy in the field mapping task. More importantly, we found a Visuospatial Ability × Geological Knowledge interaction, such that visuospatial ability positively predicted mapping performance at low, but not high, levels of geological knowledge. In other words, we found evidence to suggest that visuospatial ability mattered for bedrock mapping for the novices in our sample, but not for the experts. For experienced mappers, we found a significant correlation between GCI scores and the thoroughness with which they covered the map area, plus a relationship between speed and map accuracy such that faster mappers produced better maps. However, fast novice mappers tended to produce the worst maps. Successful mappers formed a mental model of the underlying geologic structure immediately to early in the mapping task, then spent field time collecting observations to confirm, disconfirm, or modify their initial model. In contrast, the least successful mappers (all inexperienced) rarely generated explanations or models of the underlying geologic structure in the field.

Petcovic, H. L.; Libarkin, J.; Hambrick, D. Z.; Baker, K. M.; Elkins, J. T.; Callahan, C. N.; Turner, S.; Rench, T. A.; LaDue, N.

2011-12-01

245

Medical geology: a globally emerging discipline  

Microsoft Academic Search

Medical Geology, the study of the impacts of geologic materials and processes on animal and human health, is a dynamic emerging discipline bringing together the geoscience, biomedical, and public health communities to solve a wide range of environmental health problems. Among the Medical Geology described in this review are examples of both deficiency and toxicity of trace element exposure. Goiter

Joseph E. Bunnell; Robert B. Finkelman; Jose A. Centeno; O. Selinus

2007-01-01

246

The Importance of Sample Processing in Analysis of Asbestos Content in Rocks and Soils  

NASA Astrophysics Data System (ADS)

Analysis of asbestos content in rocks and soils using Air Resources Board (ARB) Test Method 435 (M435) involves the processing of samples for subsequent analysis by polarized light microscopy (PLM). The use of different equipment and procedures by commercial laboratories to pulverize rock and soil samples could result in different particle size distributions. It has long been theorized that asbestos-containing samples can be over-pulverized to the point where the particle dimensions of the asbestos no longer meet the required 3:1 length-to-width aspect ratio or the particles become so small that they no longer can be tested for optical characteristics using PLM where maximum PLM magnification is typically 400X. Recent work has shed some light on this issue. ARB staff conducted an interlaboratory study to investigate variability in preparation and analytical procedures used by laboratories performing M435 analysis. With regard to sample processing, ARB staff found that different pulverization equipment and processing procedures produced powders that have varying particle size distributions. PLM analysis of the finest powders produced by one laboratory showed all but one of the 12 samples were non-detect or below the PLM reporting limit; in contrast to the other 36 coarser samples from the same field sample and processed by three other laboratories where 21 samples were above the reporting limit. The set of 12, exceptionally fine powder samples produced by the same laboratory was re-analyzed by transmission electron microscopy (TEM) and results showed that these samples contained asbestos above the TEM reporting limit. However, the use of TEM as a stand-alone analytical procedure, usually performed at magnifications between 3,000 to 20,000X, also has its drawbacks because of the miniscule mass of sample that this method examines. The small amount of powder analyzed by TEM may not be representative of the field sample. The actual mass of the sample powder analyzed by PLM is about six orders of magnitude greater than that analyzed by TEM and, thus, more likely to be representative of the field sample. TEM results do not always match those of PLM from the same sample because TEM examines smaller fibers/particles than PLM, analyzes less subsample mass, and has results typically expressed in different units (e.g., percent by weight, visual estimate, or point count). Paired PLM and TEM analyses of field samples taken by the California Department of Toxic Substances Control (DTSC) illustrate this point. Processing quality control (QC) checks could be implemented to limit the number of artificial PLM non-detects. Example QC processing checks include properly calibrating processing equipment and periodic particle size analysis, such as dry sieving of the powdered samples. In addition, some government agencies use a combination of analytical techniques when analyzing for asbestos. For instance, the State of New York prescribes the use of PLM but requires TEM to verify non-detects by PLM for non-friable organically bound materials. Homogenization after sample pulverization is another appropriate processing element that should garner more attention. Homogenization equipment currently exist that, when used properly, could greatly improve the accuracy, precision, and representativeness of sample results.

Neumann, R. D.; Wright, J.

2012-12-01

247

The important role of lipid peroxidation processes in aging and age dependent diseases.  

PubMed

Any change in the cell membrane structure activates lipoxygenases (LOX). LOX transform polyunsaturated fatty acids (PUFAs) to lipidhydroperoxide molecules (LOOHs). When cells are severely wounded, this physiological process switches to a non-enzymatic lipid peroxidation (LPO) process producing LOO* radicals. These oxidize nearly all-biological molecules such as lipids, sugars, and proteins. The LOO* induced degradations proceed by transfer of the radicals from cell to cell like an infection. The chemical reactions induced by LO* and LOO* radicals seem to be responsible for aging and induction of age dependent diseases.Alternatively, LO* and LOO* radicals are generated by frying of fats and involve cholesterol-PUFA esters and thus induce atherogenesis. Plants and algae are exposed to LOO* radicals generating radiation. In order to remove LOO* radicals, plants and algae transform PUFAs to furan fatty acids, which are incorporated after consumption of vegetables into mammalian tissues where they act as excellent scavengers of LOO* and LO* radicals. PMID:17914157

Spiteller, Gerhard

2007-09-01

248

The importance of small-scale dynamics on large-scale magmatic processes  

NASA Astrophysics Data System (ADS)

Magmatic processes, from the production of melts in the upper mantle to their crystallization or eruption at the surface, are dominated by dynamical processes that occur over a wide range of timescales and lengthscales. The work presented in this dissertation develops multiscale numerical and theoretical methods to assess the role of small-scale processes for large-scale dynamics. The different studies highlight specific problems associated with the production, transport, storage and eruption of silicate melts. The different sections are organized in a "chronological", or depth decreasing order, from the production of silicate melts to their eruption at the surface. The first part of the dissertation focuses on the mass and enthalpy balance between the upper mantle and the lower continental crust. More specifically, the melt production and extraction rates from the mantle following crustal foundering are calculated. The melt extraction is strongly controlled by the development of permeability which is dominated by crystal-scale processes. The distribution of melt and the evolution of permeability in the upwelling mantle as it melts also influences the large-scale mantle flow. This study focuses on the potential of crustal foundering in a mature continental crust to generate enough melt to explain so-called magmatic flare-up episodes. The second part of the dissertation, presents a study of different aspect of the dynamics of large silicic shallow magma bodies, with an emphasis on the dynamics of crystal-rich evolved magmas (mostly dacites), their reactivation and the role played by percolating volatiles on their rejuvenation. The third section of the dissertation focuses on the role of exsolved volatiles on conduit dynamics and eruption behavior. The momentum coupling (drag) between the ascending magma and the exsolved volatiles (bubbles) is key to address the presence of fragmentation and hence the explosivity of low viscosity magma eruptions. A lattice Boltzmann multiphase model is used to parameterize the dynamics at the bubble scale as a subgrid scale model for two dimensional conduit flow calculations.

Huber, Christian

249

The potential importance of bacterial processes in regulating rate of lake acidification  

Microsoft Academic Search

Rates of microbial reduction of Oâ, Fe\\/sup 3 +\\/, Mn\\/sup 4 +\\/, NOâ⁻, and total generation of COâ and CHâ were measured in the hypolimnia of three Canadian Shield lakes. Methanogenesis accounted for 72-80% of anoxic carbon generation, while sulfate reduction contributed 16-20%. The remainder of anoxic carbon generation (2-8%) originated from all of the other processes combined (nitrate, iron,

C. A. Kelly; J. W. Rudd; R. B. Cook; D. W. Schindler

1982-01-01

250

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

251

GPIHBP1--an endothelial cell molecule important for the lipolytic processing of chylomicrons  

PubMed Central

Purpose of review This review summarizes recent data indicating that glycosylphosphatidylinositol-anchored high density lipoprotein–binding protein 1 (GPIHBP1) plays a key role in the lipolytic processing of chylomicrons. Recent findings Lipoprotein lipase (LpL) hydrolyzes triglycerides in chylomicrons at the luminal surface of the capillaries in heart, adipose tissue, and skeletal muscle. However, the endothelial cell molecule that facilitates the lipolytic processing of chylomicrons has never been clearly defined. Mice lacking GPIHBP1 manifest chylomicronemia, with plasma triglyceride levels as high as 5,000 mg/dl. In wild-type mice, GPIHBP1 is expressed on the luminal surface of capillaries in heart, adipose tissue, and skeletal muscle. Cells transfected with GPIHBP1 bind both chylomicrons and LpL avidly. Summary The chylomicronemia in Gpihbp1-deficient mice, the fact that GPIHBP1 is located within the lumen of capillaries, and the fact that GPIHBP1 binds LpL and chylomicrons suggest that GPIHBP1 is a key platform for the lipolytic processing of triglyceride-rich lipoproteins.

Young, Stephen G.; Davies, Brandon S. J.; Fong, Loren G.; Gin, Peter; Weinstein, Michael M.; Bensadoun, Andre; Beigneux, Anne P.

2010-01-01

252

Processing single-use medical devices for use in surgery - importance, status quo and potential.  

PubMed

In summary, it is possible with the technology and scientific knowledge currently available to allow products intended for single use to be reprocessed using validated and certified processing procedures, while maintaining the full function and without any loss in quality. How many times a product can be re-processed must be determined separately for each individual medical technology device; it is not possible to make any kind of blanket statement as to the permissible number of cycles. This is due to the differing construction, the various combinations of materials and the diverse demands made of each device during clinical use. The exigency of the reprocessing issue is evident both to the user and the primary manufacturer. For the user, where there is a correspondingly high-quality primary product with suitably costed, technically-sound and certified reprocessing procedures, repeat usage can mean real savings while maintaining full functionality in each use. For the primary manufacturers of highly specialised instruments, only part of which can be represented by the medical facility in terms of a corresponding DRG (Diagnosis-Related Group), it is reprocessing that opens the door to widespread routine clinical use. The patient, in turn, benefits greatly from this, since his demand for medical treatment using the most up-to-date technology is taken into account. If processing complies in full with medical technology and hygiene directives, from the medical point of view (without being able to definitively evaluate each individual case using this criterion) the specific advantages of the reprocessing procedure are obvious. In order to establish broad acceptance for the purposes of good marketing, corresponding controlling and quality instruments have to be developed to allow the decision-making process regarding the permissibility of the reprocessing of a certain device and the number of times it can be reprocessed using this procedure to be made transparent.Taking this a step further, possibilities arise for the establishment of corresponding quality-assurance instruments on the part of the clinical establishments involved, within which reprocessed products, in the interest of quality assurance, can be referred back to the processor in the event of defective function and can also be removed from clinical use prior to completing the intended number of processing cycles. Furthermore, it can be assumed that the widespread use of reprocessing procedures in today's high-cost single-use medical device sector will have a long-term cost/price-regulating effect for the primary products, to the benefit of the users. Thus, the heated debate regarding the safety of processing procedures that have already been certified and validated in accordance with current industry standards should be evaluated in particular from the point of view of the justified fears of the leading manufacturers with regard to their currently established market share. From a purely surgical point of view, the reprocessing of disposable products should be welcomed as a revolution. The main criteria for surgeons and medics should always be the benefit for the patient. If the quality is ensured through corresponding processing and validation procedures based on recognised certificates, then economic arguments take precedence. Cases in which a DRG (and thus a payment calculation) does not fully cover the use of medical devices are conceivable. Withholding medically necessary services on grounds of the costs, or making these services available to a limited extent only, is not acceptable from the medical point of view and furthermore goes beyond what is ethically acceptable. Each procedure, even the systematic use of reprocessing of suitable medical technology disposable items, should, where the quality is guaranteed, be supported unequivocally. Taken a step further, this branch of the economy will have a long-lasting price-regulating effect on the primary producers market. PMID:20204093

Krüger, Colin M

2008-01-01

253

Histamine levels in commercially important fresh and processed fish of Oman with reference to international standards.  

PubMed

Histamine was investigated in fresh (378), frozen (441), canned (290) and dried (24) fish samples of scombroid and non-scombroid species of Oman using a high performance liquid chromatography with a fluorescence detector. Of the 1133 fish samples tested, histamine was detected in 551 samples with a detection rate of about 41.8% among fresh fish, 61.0% of frozen fish, 78.9% of canned fish and 91.6% of dried fish samples and the mean histamine levels were 2.6, 5.8, 3.1 and 104mgkg(-1), respectively. A total of 3.7% and 0.79% of the total samples exceeded the FDA and EU regulatory limits for histamine. Imported dried anchovies contained high histamine levels. The study confirms that post catching and commercialisation practices of seafood are adequate, warranting good quality fish and may not cause histamine risk to consumer in terms of human diet. While necessary monitoring may be done for imported dried fish products. PMID:23692766

Yesudhason, Poulose; Al-Zidjali, Mehdia; Al-Zidjali, Alia; Al-Busaidi, Moza; Al-Waili, Aaliah; Al-Mazrooei, Nashwa; Al-Habsi, Saoud

2013-10-15

254

Solution conditions determine the relative importance of nucleation and growth processes in ?-synuclein aggregation.  

PubMed

The formation of amyloid fibrils by the intrinsically disordered protein ?-synuclein is a hallmark of Parkinson disease. To characterize the microscopic steps in the mechanism of aggregation of this protein we have used in vitro aggregation assays in the presence of preformed seed fibrils to determine the molecular rate constant of fibril elongation under a range of different conditions. We show that ?-synuclein amyloid fibrils grow by monomer and not oligomer addition and are subject to higher-order assembly processes that decrease their capacity to grow. We also find that at neutral pH under quiescent conditions homogeneous primary nucleation and secondary processes, such as fragmentation and surface-assisted nucleation, which can lead to proliferation of the total number of aggregates, are undetectable. At pH values below 6, however, the rate of secondary nucleation increases dramatically, leading to a completely different balance between the nucleation and growth of aggregates. Thus, at mildly acidic pH values, such as those, for example, that are present in some intracellular locations, including endosomes and lysosomes, multiplication of aggregates is much faster than at normal physiological pH values, largely as a consequence of much more rapid secondary nucleation. These findings provide new insights into possible mechanisms of ?-synuclein aggregation and aggregate spreading in the context of Parkinson disease. PMID:24817693

Buell, Alexander K; Galvagnion, Céline; Gaspar, Ricardo; Sparr, Emma; Vendruscolo, Michele; Knowles, Tuomas P J; Linse, Sara; Dobson, Christopher M

2014-05-27

255

Solution conditions determine the relative importance of nucleation and growth processes in ?-synuclein aggregation  

PubMed Central

The formation of amyloid fibrils by the intrinsically disordered protein ?-synuclein is a hallmark of Parkinson disease. To characterize the microscopic steps in the mechanism of aggregation of this protein we have used in vitro aggregation assays in the presence of preformed seed fibrils to determine the molecular rate constant of fibril elongation under a range of different conditions. We show that ?-synuclein amyloid fibrils grow by monomer and not oligomer addition and are subject to higher-order assembly processes that decrease their capacity to grow. We also find that at neutral pH under quiescent conditions homogeneous primary nucleation and secondary processes, such as fragmentation and surface-assisted nucleation, which can lead to proliferation of the total number of aggregates, are undetectable. At pH values below 6, however, the rate of secondary nucleation increases dramatically, leading to a completely different balance between the nucleation and growth of aggregates. Thus, at mildly acidic pH values, such as those, for example, that are present in some intracellular locations, including endosomes and lysosomes, multiplication of aggregates is much faster than at normal physiological pH values, largely as a consequence of much more rapid secondary nucleation. These findings provide new insights into possible mechanisms of ?-synuclein aggregation and aggregate spreading in the context of Parkinson disease.

Buell, Alexander K.; Galvagnion, Celine; Gaspar, Ricardo; Sparr, Emma; Vendruscolo, Michele; Knowles, Tuomas P. J.; Linse, Sara; Dobson, Christopher M.

2014-01-01

256

The importance of unsaturated zone biogeochemical processes in determining groundwater composition, southeastern Australia  

NASA Astrophysics Data System (ADS)

Analysis of soil, soil water and groundwater in the Mount William Creek catchment, southeastern Australia, shows that Mg2+ and Ca2+ within infiltrating rainfall are rapidly depleted by plant uptake and adsorption on clay minerals. Na+ and K+ may exhibit minor enrichment at shallow depths but are quickly readsorbed, so that cation/Cl- ratios typical of groundwater are observed in soil water within the upper 200 cm of the soil profile for all species. The concentrations of K+ and Ca2+ in soil and groundwater are more depleted than Na+ and Mg2+ due to preferential uptake by vegetation. Removal of organic matter results in a continuing, long-term export of all major cations from the soil profiles. The processes of biogeochemical fractionation within the unsaturated zone rapidly modify the cation/Cl- ratios of infiltrating rainfall to values characteristic of seawater. These mechanisms may have reached steady state, because groundwaters with seawater ion/Cl- ratios are thousands of years old; the exchange sites on the soil clays are probably saturated, so cations supplied in rainfall are exported in organic matter and incorporated into recharge infiltrating into the groundwater. Much of the chemical evolution of groundwater traditionally attributed to processes within the aquifer is complete by the time recharge occurs; this evolutionary model may have broad application.

Edwards, Matthew; Webb, John

2009-09-01

257

Sea-ice processes in the Laptev Sea and their importance for sediment export  

USGS Publications Warehouse

Based on remote-sensing data and an expedition during August-September 1993, the importance of the Laptev Sea as a source area for sediment-laden sea ice was studied. Ice-core analysis demonstrated the importance of dynamic ice-growth mechanisms as compared to the multi-year cover of the Arctic Basin. Ice-rafted sediment (IRS) was mostly associated with congealed frazil ice, although evidence for other entrainment mechanisms (anchor ice, entrainment into freshwater ice) was also found. Concentrations of suspended particulate matter (SPM) in patches of dirty ice averaged at 156 g m-3 (standard deviation ?? = 140 g m-3), with a background concentration of 5 g m-3. The potential for sediment entrainment over the broad, shallow Laptev Sea shelf during fall freeze-up was studied through analysis of remote-sensing data and weather-station records for the period 1979-1994. Freeze-up commences on 26 September (?? = 7 d) and is completed after 19 days (?? = 6 d). Meteorological conditions as well as ice extent prior to and during freeze-up vary considerably, the open-water area ranging between 107 x 103 and 447 x 103 km2. Ice motion and transport of IRS were derived from satellite imagery and drifting buoys for the period during and after the expedition (mean ice velocities of 0.04 and 0.05 m s-1, respectively). With a best-estimate sediment load of 16 t km-2 (ranging between 9 and 46 t km-2), sediment export from the eastern Laptev Sea amounts to 4 x 10-6 t yr-1, with extremes of 2 x 10-6 and 11 x 106 t yr-1. Implications for the sediment budget of the Laptev shelf, in particular with respect to riverine input of SPM, which may be of the same order of magnitude, are discussed.

Eicken, H.; Reimnitz, E.; Alexandrov, V.; Martin, T.; Kassens, H.; Viehoff, T.

1997-01-01

258

Ontology for Structural Geology  

NASA Astrophysics Data System (ADS)

We present our comprehensive process-based ontology for Structural Geology. This ontology covers major domain concepts, especially those related to geological structure type, properties of these structures, their deformation mechanisms, and the factors that control which deformation mechanisms may operate under certain conditions. The structure class in our ontology extends the planetary structure class of the SWEET ontology by providing additional information required for use in the structural geology domain. The classification followed the architectures of structures, such as structure element, set, zone, and pattern. Our deformation mechanism class does not have a corresponding class in SWEET. In our ontology, it has two subclasses, Macro- and Micro- mechanisms. The property class and the factor class are both subclasses of the physical property class of SWEET. Relationships among those concepts are also included in our ontology. For example, the class structure element has properties associated with the deformation mechanisms, descriptive properties such as geometry and morphology, and physical properties of rocks such as strength, compressibility, seismic velocity, porosity, and permeability. The subject matter expertise was provided by domain experts. Additionally, we surveyed text books and journal articles with the goal of evaluating the completeness and correctness of the domain terms and we used logical reasoners and validators to eliminate logical problems. We propose that our ontology provides a reusable extension to the SWEET ontology that may be of value to scientists and lay people interested in structural geology issues. We have also implemented prototype services that utilize this ontology for search.

Zhong, J.; McGuinness, D. L.; Antonellini, M.; Aydin, A.

2005-12-01

259

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

260

Extracting important information from Chinese Operation Notes with natural language processing methods.  

PubMed

Extracting information from unstructured clinical narratives is valuable for many clinical applications. Although natural Language Processing (NLP) methods have been profoundly studied in electronic medical records (EMR), few studies have explored NLP in extracting information from Chinese clinical narratives. In this study, we report the development and evaluation of extracting tumor-related information from operation notes of hepatic carcinomas which were written in Chinese. Using 86 operation notes manually annotated by physicians as the training set, we explored both rule-based and supervised machine-learning approaches. Evaluating on unseen 29 operation notes, our best approach yielded 69.6% in precision, 58.3% in recall and 63.5% F-score. PMID:24486562

Wang, Hui; Zhang, Weide; Zeng, Qiang; Li, Zuofeng; Feng, Kaiyan; Liu, Lei

2014-04-01

261

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

262

The importance of water for high fidelity information processing and for life  

NASA Astrophysics Data System (ADS)

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 of approximately 10^7:1 at each position, 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 association representing 3 units of information (e.g., 3 base pairs) with specificity of 10^7 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, T. M.; Pohorille, A.

2011-12-01

263

Importance of basal processes in simulations of a surging Svalbard outlet glacier  

NASA Astrophysics Data System (ADS)

The outlet glacier of Basin 3 (B3) of Austfonna icecap, Svalbard, has increased in velocity dramatically since 1995. B3 is known to exhibit a seasonal summer speed up associated with the melt season, and has accelerated approximately five fold in terms of pre-melt velocity. We use the Elmer/Ice full Stokes model for ice dynamics to infer spatial distributions of basal drag for pre-melt time periods in 1995, 2008 and 2011. This "inverse" method is based on minimising discrepancy between modelled and observed surface velocities, using satellite based velocity fields. We generate steady state temperature distributions for the three time periods. Frictional heating caused by basal sliding contributes significantly to basal temperatures of the B3 outlet glacier, which exhibits a uniform steady state basal temperature at pressure melting point in all three cases. We present a sensitivity experiment consisting of transient simulations under present day forcing to demonstrate that using a temporally fixed basal drag field obtained through inversion can lead to thickness change errors of the order of 2m per year. Hence it is essential to incorporate in a model for future projection the evolution of basal processes governing outlet glacier speed. Informed by a combination of our inverse method results and previous studies, we hypothesize a system of processes and feedbacks involving till deformation and basal hydrology to explain both the summer speed up and the ongoing pre-melt speed up, and speculate on the wider relevance of deformable till mechanics to non-surging glaciers.

Gladstone, Rupert; Schäfer, Martina; Zwinger, Thomas; Strazzi, Tazio; Gong, Yongmei; Moore, John; Dunse, Thorben

2013-04-01

264

Personal Computer (PC) - Based Methods for Integrating, Processing and Visualizing Multivariate Data: Review of Geology, Till Geochemistry, Lake Sediment Geochemistry, and Airborne Geophysical Data from the Beardmore- Geraldton District, Ontario, Canada  

Microsoft Academic Search

2 Multivariate data collected from geological, geochemical and geophysical sources historically have not been managed and evaluated in a single PC-based environment. This tendency is, in part, due to the lack of techniques for integrating, processing and visualizing high-volume datasets from different sources. In this short discussion, the objective is to review the methodologies used to integrate, process and visualize

Greg Hollyer; L. Harvey Thorleifson

265

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

266

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

267

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

268

Microbial concentrations on fresh produce are affected by postharvest processing, importation, and season.  

PubMed

In the United States, the proportion of foodborne illness outbreaks associated with consumption of contaminated domestic and imported fresh fruits and vegetables (produce) has increased over the past several decades. To address this public health concern, the goal of this work was to identify and quantify factors associated with microbial contamination of produce in pre- and postharvest phases of the farm-to-fork continuum. From 2000 to 2003, we collected 923 samples of 14 types of produce (grown in the southern United States or in the northern border states of Mexico) from 15 farms and eight packing sheds located in the southern United States. To assess microbial quality, samples were enumerated for Escherichia coli, total aerobic bacteria, total coliforms, and total Enterococcus. Most produce types had significantly higher microbial concentrations when sampled at the packing shed than when sampled at the farm. In addition, we observed seasonal differences in the microbial concentrations on samples grown in the United States, with higher mean indicator concentrations detected in the fall (September, October, and November). We developed a predictive, multivariate logistic regression model to identify and quantify factors that were associated with detectable concentrations of E. coli contamination on produce. These factors included produce type (specifically, cabbage or cantaloupe), season of collection (harvested in the fall), and packing step (bin, box, conveyor belt, or turntable). These results can be used to identify specific mechanisms of produce contamination and propose interventions that may decrease the likelihood of produce-associated illness. PMID:19244889

Ailes, Elizabeth C; Leon, Juan S; Jaykus, Lee-Ann; Johnston, Lynette M; Clayton, Haley A; Blanding, Sarah; Kleinbaum, David G; Backer, Lorraine C; Moe, Christine L

2008-12-01

269

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.

270

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

271

Geology of California  

SciTech Connect

This book reviews some of the basic principles of geology and includes a chapter on the Klamath Mountains. Chapters cover the geologic history of California and the geologic features of the various deserts, mountain ranges, plateaus, basins, and valleys of the state, including offshore geology and the San Andreas fault. The authors discuss exotic and suspect terranes, and current theories concerning California geology.

Norris, R.M.; Webb, R.W.

1990-01-01

272

Radiometric dating in geology  

NASA Astrophysics Data System (ADS)

The method of dating rocks and minerals is known as geochronology. Although in principle this term could be applied to estimation of relative ages according to traditional geological observation, it is nowadays usually restricted to the quantitative measurement of geological time using the constant-rate natural process of radioactive decay. 14C dating is a technique based on measuring the residual radioactivity of this isotope which decays exponentially from the time of death of organisms which extract it from the atmosphere (e.g. when a living tree becomes simply 'wood'). The halflife of this decay is only 5600 years. Even using pre-concentration techniques and highly sensitive detectors, the practical range of the dating method does not extend back beyond about 100000 years-a period utterly insignificant in terms of the geological evolution of the Earth, which extends over the past 4500 million years. For geological dating one requires naturally occurring elements with much longer halflives. Most of the handful of appropriate decay schemes are listed. Most of the parent elements are rare metal constituents in the bulk chemical composition of the Earth. For such 'trace' elements it is generally convenient to express their concentration in natural materials in parts per million by weight (ppm) and even in the one case of a fairly common element (potassium) only a very small proportion occurs as the radioactive 40K. Also, some of the halflives are very long, even by geological reckoning, so that the actual level of natural radioactivity is rarely more than a few disintegrations per minute per gram.

Pankhurst, R. J.

1980-11-01

273

Natural gas composition in a geological environment and the implications for the processes of generation and preservation  

Microsoft Academic Search

Gases recovered from their location of formation (for example, gas recovered from drill cuttings) are enriched in C2+ components relative to gases recovered from reservoir production or testing streams. Because reservoir gases have been derived through a series of processes including generation from a source with a specific chemical character, primary and secondary migration, accumulation and (selective) preservation, the compound

Lloyd R. Snowdon

2001-01-01

274

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

Microsoft Academic Search

Spring deposits are predicted as a result of former aquifers on Mars. This study examines the large-scale morphology and their physical processes of formation, growth, and evolution in terms that relate to the search for former aqueous environments on Mars.

L. S. Crumpler

2003-01-01

275

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

276

The Serra Pelada Au-PGE deposit, Serra dos Carajás (Pará State, Brazil): geological and geochemical indications for a composite mineralising process  

NASA Astrophysics Data System (ADS)

The Serra Pelada Au-PGE-rich deposit is located in the Serra dos Carajás, a leading mining area in Brazil. This region is characterised by a complex geological and structural framework and is affected by deep lateritisation which has lasted for more than 70 Ma. The Serra Pelada deposit is emplaced in a late-Archean low-grade metasedimentary sequence (Rio Fresco/Águas Claras Formation) which is host to other gold deposits in the region (Igarapé Bahia, Águas Claras). The Rio Fresco/Águas Claras sequence was deposited in tectonic basins developed on Archean basement and Au-bearing greenstone terranes which were intruded by PGE-rich layered mafic complexes (e.g. Luanga). The Serra Pelada mineralisation is located along a regional, complex system of strike-slip faults (Cinzento-Carajás systems) which were active during the late Archean to early Proterozoic. The mineralisation appears to be concentrated along a faulted hinge zone of a fold. Ore zone rock facies are dominated by low-grade ferruginous to carbonaceous metasiltstones and minor sandstones, locally brecciated and cemented by quartz (±sulphide) stockwork. Supergene alteration led to partial to total transformation into friable aggregates of kaolinite, Fe oxide-hydroxides, silica and secondary phosphate-sulphates even at depths exceeding 200 m. Precious metals are exceptionally enriched, with up to more than 1,000 ppm Au+PGE in some peculiar ferruginous-graphitic zones locally called "hidrotermalito". Geochemistry shows complex patterns of major and trace elements, particularly rare-earth elements (REE), in mineralised vs. nonmineralised samples. These patterns are interpreted in terms of variable degree of superposition of hydrothermal and supergene alteration. Precious metals show progressive increase from samples with hydrothermal imprint to samples with supergene imprint. The geological evolution of the Carajás region and the characteristics of mineralisation at Serra Pelada may suggest a composite mineralising process: hydrothermal activity (by fluids likely originated from granitoids) was followed by supergene alteration during long-lasting lateritisation to develop extreme precious metal enrichments in a geological context probably already anomalous for Au and PGE.

Moroni, Marilena; Girardi, Vicente A.; Ferrario, Alfredo

2001-12-01

277

Geology of a complex kimberlite pipe (K2 pipe, Venetia Mine, South Africa): insights into conduit processes during explosive ultrabasic eruptions  

Microsoft Academic Search

K2 is a steep-sided kimberlite pipe with a complex internal geology. Geological mapping, logging of drillcore and petrographic\\u000a studies indicate that it comprises layered breccias and pyroclastic rocks of various grain sizes, lithic contents and internal\\u000a structures. The pipe comprises two geologically distinct parts: K2 West is a layered sequence of juvenile- and lithic-rich\\u000a breccias, which dip 20–45° inwards, and

R. J. Brown; M. Tait; M. Field; R. S. J. Sparks

2009-01-01

278

An evaluation of the ERTS data collection system as a potential operational tool. [automatic hydrologic data collection and processing system for geological surveys  

NASA Technical Reports Server (NTRS)

The Earth Resources Technology Satellite Data Collection System has been shown to be, from the users vantage point, a reliable and simple system for collecting data from U.S. Geological Survey operational field instrumentation. It is technically feasible to expand the ERTS system into an operational polar-orbiting data collection system to gather data from the Geological Survey's Hydrologic Data Network. This could permit more efficient internal management of the Network, and could enable the Geological Survey to make data available to cooperating agencies in near-real time. The Geological Survey is conducting an analysis of the costs and benefits of satellite data-relay systems.

Paulson, R. W.

1974-01-01

279

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

280

Precise determination of ?88Sr in rocks, minerals, and waters by double-spike TIMS: A powerful tool in the study of chemical, geologic, hydrologic and biologic processes  

USGS Publications Warehouse

We present strontium isotopic (88Sr/86Sr and 87Sr/86Sr) results obtained by 87Sr–84Sr double spike thermal ionization mass-spectrometry (DS-TIMS) for several standards as well as natural water samples and mineral samples of abiogenic and biogenic origin. The detailed data reduction algorithm and a user-friendly Sr-specific stand-alone computer program used for the spike calibration and the data reduction are also presented. Accuracy and precision of our ?88Sr measurements, calculated as permil (‰) deviations from the NIST SRM-987 standard, were evaluated by analyzing the NASS-6 seawater standard, which yielded ?88Sr = 0.378 ± 0.009‰. The first DS-TIMS data for the NIST SRM-607 potassium feldspar standard and for several US Geological Survey carbonate, phosphate, and silicate standards (EN-1, MAPS-4, MAPS-5, G-3, BCR-2, and BHVO-2) are also reported. Data obtained during this work for Sr-bearing solids and natural waters show a range of ?88Sr values of about 2.4‰, the widest observed so far in terrestrial materials. This range is easily resolvable analytically because the demonstrated external error (±SD, standard deviation) for measured ?88Sr values is typically ?0.02‰. It is shown that the “true” 87Sr/86Sr value obtained by the DS-TIMS or any other external normalization method combines radiogenic and mass-dependent mass-fractionation effects, which cannot be separated. Therefore, the “true” 87Sr/86Sr and the ?87Sr parameter derived from it are not useful isotope tracers. Data presented in this paper for a wide range of naturally occurring sample types demonstrate the potential of the ?88Sr isotope tracer in combination with the traditional radiogenic 87Sr/86Sr tracer for studying a variety of biological, hydrological, and geological processes.

Neymark, Leonid A.; Premo, Wayne R.; Mel'nikov, Nikolay N.; Emsbo, Poul

2014-01-01

281

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

Microsoft Academic Search

The relationships between stratigraphic and tectonic setting, recharge processes and underground drainage of the glacierised\\u000a karst aquifer system ‘Tsanfleuron-Sanetsch’ in the Swiss Alps have been studied by means of various methods, particularly\\u000a tracer tests (19 injections). The area belongs to the Helvetic nappes and consists of Jurassic to Palaeogene sedimentary rocks.\\u000a Strata are folded and form a regional anticlinorium. Cretaceous

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

2009-01-01

282

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

283

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.

284

The importance of local and landscape-scale processes to the occupancy of wetlands by pond-breeding amphibians  

USGS Publications Warehouse

Variation in the distribution and abundance of species across landscapes has traditionally been attributed to processes operating at fine spatial scales (i.e., environmental conditions at the scale of the sampling unit), but processes that operate across larger spatial scales such as seasonal migration or dispersal are also important. To determine the relative importance of these processes, we evaluated hypothesized relationships between the probability of occupancy in wetlands by two amphibians [wood frogs (Lithobates sylvaticus) and boreal chorus frogs (Pseudacris maculata)] and attributes of the landscape measured at three spatial scales in Rocky Mountain National Park, Colorado. We used cost-based buffers and least-cost distances to derive estimates of landscape attributes that may affect occupancy patterns from the broader spatial scales. The most highly ranked models provide strong support for a positive relationship between occupancy by breeding wood frogs and the amount of streamside habitat adjacent to a wetland. The model selection results for boreal chorus frogs are highly uncertain, though several of the most highly ranked models indicate a positive association between occupancy and the number of neighboring, occupied wetlands. We found little evidence that occupancy of either species was correlated with local-scale attributes measured at the scale of individual wetlands, suggesting that processes operating at broader scales may be more important in influencing occupancy patterns in amphibian populations.

Scherer, Rick D.; Muths, Erin; Noon, Barry R.

2012-01-01

285

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

286

Geology of the Caribbean  

USGS Publications Warehouse

The Venezuelan and Colombian basins are located on the Caribbean Plate whilst the Yucatan basin is on the North American Plate. The processes occurring at the boundaries between the Caribbean Plate and the adjacent North American, South American and Cocos Plates, and the resulting surface features and patterns of volcanic and earthquake activity are described. Most of the Caribbean area is floored by atypical oceanic crust and its most valuable main geologic resources identified so far are petroleum, together with sand and gravel. Geological research is being carried out with techniques for broad-range swath imaging of the seafloor, such as GLORIA, and for directly measuring the movement between plates. -J.G.Harvey

Dillon, W. P.; Edgar, N. T.; Scanlon, K. M.; Klitgord, K. D.

1987-01-01

287

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

288

Hydrothermal ore-forming processes in the light of studies in rock- buffered systems: II. Some general geologic applications  

USGS Publications Warehouse

The experimental metal solubilities for rock-buffered hydrothermal systems provide important insights into the acquisition, transport, and deposition of metals in real hydrothermal systems that produced base metal ore deposits. Water-rock reactions that determine pH, together with total chloride and changes in temperature and fluid pressure, play significant roles in controlling the solubility of metals and determining where metals are fixed to form ore deposits. Deposition of metals in hydrothermal systems occurs where changes such as cooling, pH increase due to rock alteration, boiling, or fluid mixing cause the aqueous metal concentration to exceed saturation. Metal zoning results from deposition occurring at successive saturation surfaces. Zoning is not a reflection simply of relative solubility but of the manner of intersection of transport concentration paths with those surfaces. Saturation surfaces will tend to migrate outward and inward in prograde and retrograde time, respectively, controlled by either temperature or chemical variables. -from Authors

Hemley, J. J.; Hunt, J. P.

1992-01-01

289

Geologic Mapping on Mars  

NSDL National Science Digital Library

This lab is part of a Lunar and Planetary Geology course offered to both geology and non-geology majors, and it involves basic geological mapping of an area within the Tyrrhena Patera region on Mars. Students are encouraged to work in groups to prepare a geological map from a photomosaic map and to interpret the geologic stratigraphy from a geological map of the greater area. This activity reinforces mapping skills as well as group work skills, and aims to teach students more about Martian stratigraphy and geology through a hands-on activity.

De Villiers, Germari

290

Thermodynamic Properties of Magnesium Chloride Hydroxide Hydrate (Mg3Cl(OH)5:4H2O, Phase 5), and Its importance to Nuclear Waste Isolation in Geological Repositories in Salt Formations  

NASA Astrophysics Data System (ADS)

MgO (bulk, pure MgO corresponding to the mineral periclase) is the only engineered barrier certified by the Environmental Protection Agency for emplacement in the Waste Isolation Pilot Plant (WIPP) in the US, and an Mg(OH)2-based engineered barrier (bulk, pure Mg(OH)2 corresponding to brucite) is to be employed in the Asse repository in Germany. Both the WIPP and the Asse are located in salt formations. The WIPP is a U.S. Department of Energy geological repository being used for the permanent disposal of defense-related transuranic waste (TRU waste). The repository is 655 m below the surface, and is situated in the Salado Formation, a Permian salt bed mainly composed of halite, and of lesser amounts of polyhalite, anhydrite, gypsum, magnesite, clays and quartz. The WIPP Generic Weep Brine (GWB), a Na-Mg-Cl dominated brine, is associated with the Salado Formation. The previous vendor for MgO for the WIPP was Premier Chemicals and the current vendor is Martin Marietta Materials. Experimental studies of both Premier MgO and Martin Marietta MgO with the GWB at SNL indicate the formation of magnesium chloride hydroxide hydrate, Mg3Cl(OH)5:4H2O, termed as phase 5. However, this important phase is lacking in the existing thermodynamic database. In this study, the solubility constant of phase 5 is determined from a series of solubility experiments in MgCl2-NaCl solutions. The solubility constant at 25 oC for the following reaction, Mg3Cl(OH)5:4H2O + 5H+ = 3Mg2+ + 9H2O(l) + Cl- is recommended as 43.21±0.33 (2?) based on the Specific Interaction Theory (SIT) model for extrapolation to infinite dilution. The log K obtained via the Pitzer equations is identical to the above value within the quoted uncertainty. The Gibbs free energy and enthalpy of formation for phase 5 at 25 oC are derived as -3384±2 (2?) kJ mol-1 and -3896±6 (2?) kJ mol-1, respectively. The standard entropy and heat capacity of phase 5 at 25 oC are estimated as 393±20 J mol-1 K-1 and 374±19 J mol-1 K-1, respectively. Phase 5, and its similar phase, phase 3 (Mg2Cl(OH)3:4H2O), could have a significant role in influencing the geochemical conditions in geological repositories for nuclear waste in salt formations where MgO or brucite is employed as engineered barriers, when Na-Mg-Cl dominated brines react with MgO or brucite. Based on our solubility constant for phase 5 in combination with the literature value for phase 3, we predict that the composition for the invariant point of phase 5 and phase 3 would be mMg = 1.70 and pmH = 8.93 in the Mg-Cl binary system. The recent WIPP Compliance Recertification Application PA Baseline Calculations indicate that phase 5 instead of phase 3 is indeed a stable phase when GWB equilibrates with actinide-source-term phases, brucite, magnesium carbonates, halite and anhydrite. 1. This research is funded by WIPP programs administered by the U.S. Department of Energy. 2. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

Xiong, Y.; Deng, H.; Nemer, M. B.; Johnsen, S.

2009-12-01

291

Digital Geology of Idaho  

NSDL National Science Digital Library

This online course systematically divides Idaho geology into 15 individual teaching modules which correspond with a two-credit, 15-week classroom course. Each module covers a specific area or type of geology in the state of Idaho. Topics include geology of basement rocks, rocks and geology of the Belt Supergroup, tectonic regimes, and geologic history. There are also modules on rocks and geology of the Idaho Batholith, volcanic history and deposits of the Snake River Plain and Columbia Plateau, and Pleistocene glaciation and floods from Lakes Missoula and Bonneville. Each of the modules provides geologic maps from a recently developed Geologic Map of Idaho, produced by the Idaho Geological Survey, and most also feature fly-throughs in which geologic information is draped over topography to provide visualizations of the geology along Idaho rivers.

292

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.

293

The Geologic History of the Carbon Cycle  

NASA Astrophysics Data System (ADS)

Geologists, like other scientists, tend to view the global carbon cycle through the lens of their particular training and experience. The study of Earth's history requires a view both humbled by the knowledge of past global transformations and emboldened by the imagination of details not seen in the fragments of the rock record. In studying the past behavior of the carbon cycle, geologists are both amazed by unexpected discoveries and reassured by the extent to which "the present is the key to the past." Understanding the present-day carbon cycle has become a matter of societal urgency because of concerns about the effects of human activities on atmospheric chemistry and global climate. This public limelight has had far-reaching consequences for research on the geologic history of the carbon cycle as well as for studies of its present and future. The burgeoning new "interdiscipline" of biogeochemistry claims among its adherents many geologists as well as biologists, chemists, and other scientists. The pace of discovery demands that studies of the geologic history of the carbon cycle cannot be isolated from the context of present and future events.This chapter describes the behavior of the carbon cycle prior to human influence. It describes events and processes that extend back through geologic time and include the exchange of carbon between the Earth's surface and the long-term reservoirs in the lithosphere. Chapter 8.10 emphasizes carbon exchanges that are important over years to decades, with a focus on relatively recent human influences and prospects for change during the coming century. Chapter 4.03 presents an overview of the biogeochemistry of methane, again with emphasis on relatively recent events. In these chapters as well as in the present chapter, relationships between the carbon cycle and global climate are a central concern. Together, these chapters provide an overview of how our knowledge of the present-day carbon cycle can be applied both to contemporary issues and to the record of the past. Similarly, these chapters collectively reflect the collaborative efforts of biogeochemists to utilize information about past variations in the carbon cycle to understand both Earth's history and modern changes.This chapter begins with an overview of the carbon exchanges and processes that control the variations observed in the geologic record of the carbon cycle. Then examples of past carbon-cycle change are described, beginning with the most recent variations seen in cores drilled from glaciers and the sea floor, and concluding with the distant transformations inferred from the rock record of the Precambrian. Throughout this treatment, three themes are prominent. One is that different processes control carbon cycling over different timescales. A second theme is that relatively "abrupt" changes have played a central role in the evolution of the carbon cycle throughout Earth's history. The third theme is that the geologic cycling of carbon over all timescales passes through the atmosphere and the hydrosphere, and "it is this common course that unites the entire carbon cycle and allows even its most remote constituents to influence our environment and biosphere" (Des Marais, 2001).The description of geologic events in this chapter includes examples from a broad span of the geologic record, but does not distribute attention in proportion to the distribution of geologic time in Earth's history. Readers will note, in particular, a disproportional emphasis on the Quaternary period, the most recent but briefest of geologic periods. The reason for this emphasis is twofold. First, the quality of the available Quaternary record of carbon-cycle change is far better than that available for earlier geologic periods. Second, the Quaternary record reveals a particularly illuminating array of details about interactions among the atmosphere, the biosphere, and the hydrosphere - the subset of the carbon cycle that must be understood in order to comprehend carbon cycling over nearly all times and t

Sundquist, E. T.; Visser, K.

2003-12-01

294

The NASA\\/USGS Planetary Geologic Mapping Program  

Microsoft Academic Search

NASA's Planetary Geologic Mapping Program (PGM) publishes geologic maps of the planets based on released, geodetically controlled spacecraft data. The general objectives of PGM include (1) production of geologic maps that will greatly increase our knowledge of the materials and processes that have contributed to the evolution of Solar System bodies, and (2) geologic surveys of areas of special interest

K. Tanaka

2006-01-01

295

Turning Geological Data into Reliable Mineral Resource Estimates1  

Microsoft Academic Search

This paper deals with the building of geological interpretations from necessarily limited geological data and the use of such interpretations in the estimation of mineral resources. Since geological interpretations are a type of scientific model, the process of constructing such models in terms of the objectives and mechanics involved is briefly reviewed. Particular aspects of geological interpretations relevant to resource

John Vann

296

Geological hazards risk regionalization based on GIS in Chongzhou city  

Microsoft Academic Search

After Wenchuan Earthquake on May 12, 2008, various geological hazards happened frequently in Chongzhou city, Sichuan.This paper analyzes factors inducing hazards by weighted comprehensive evaluation (WCE) and analytic hierarchy process (AHP), and builds the geological hazards assessment model.On the basis, the map of geological hazards lability zoning is drew. The study shows that geological hazards in Chongzhou city are mainly

Chengqiang Shu; Liangqun Jiang

2011-01-01

297

Geology 201: Non-linear processes in geofluids or Why does the Earth look the way it does?  

NASA Astrophysics Data System (ADS)

Many patterns we observe on the Earth’s surface are a result of fluid transport, fluxes, and phase changes. Coastlines, drainage networks, river deltas, types of rock deformation and the driving mechanism for plate tectonics all result from fluid flows exhibiting complex behavior. Currently, undergraduate students often do not have conceptual frameworks necessary for understanding non-linear systems. Their prior experiences have often emphasized linear and non-directional relationships, but most physical systems are inherently nonlinear in nature. We have found it difficult to explain ideas such as feedbacks, hysteresis, and phase transitions to students without prior exposure to complex system behavior. Here we will present a curriculum designed for sophomore-level undergraduates that will use concepts of flow to explain origin of the features we see on the Earth’s surface, while simultaneously teaching fundamental properties of complex-system behavior. Example features will come from tectonics, mantle convection, geomorphology, and hydrology. We will provide an outline of course materials where students will first be exposed to physical and conceptual models of non-linear behavior and then follow up with understanding the equations governing these processes. Examples: Rock rheologies using food analogies and then exploring material constitutive equations, stream channel avulsion using a classroom teaching flume, then a one-dimensional model of bifurcating flow in a channel. We chose the sophomore level specifically so students are introduced early in their academic career and thus have the conceptual frameworks and quantitative skills necessary to work with complex systems as they advance to upper level courses. Learning goals for the course we present will include the ability to recognize non-linear behavior, and the development of a level of comfort with these concepts.

Orr, C. H.; Cooper, C. M.

2010-12-01

298

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

PubMed

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

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

2014-01-01

299

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

300

Evaluation of three electronic report processing systems for preparing hydrologic reports of the U.S Geological Survey, Water Resources Division  

USGS Publications Warehouse

In 1987, the Water Resources Division of the U.S. Geological Survey undertook three pilot projects to evaluate electronic report processing systems as a means to improve the quality and timeliness of reports pertaining to water resources investigations. The three projects selected for study included the use of the following configuration of software and hardware: Ventura Publisher software on an IBM model AT personal computer, PageMaker software on a Macintosh computer, and FrameMaker software on a Sun Microsystems workstation. The following assessment criteria were to be addressed in the pilot studies: The combined use of text, tables, and graphics; analysis of time; ease of learning; compatibility with the existing minicomputer system; and technical limitations. It was considered essential that the camera-ready copy produced be in a format suitable for publication. Visual improvement alone was not a consideration. This report consolidates and summarizes the findings of the electronic report processing pilot projects. Text and table files originating on the existing minicomputer system were successfully transformed to the electronic report processing systems in American Standard Code for Information Interchange (ASCII) format. Graphics prepared using a proprietary graphics software package were transferred to all the electronic report processing software through the use of Computer Graphic Metafiles. Graphics from other sources were entered into the systems by scanning paper images. Comparative analysis of time needed to process text and tables by the electronic report processing systems and by conventional methods indicated that, although more time is invested in creating the original page composition for an electronically processed report , substantial time is saved in producing subsequent reports because the format can be stored and re-used by electronic means as a template. Because of the more compact page layouts, costs of printing the reports were 15% to 25% less than costs of printing the reports prepared by conventional methods. Because the largest report workload in the offices conducting water resources investigations is preparation of Water-Resources Investigations Reports, Open-File Reports, and annual State Data Reports, the pilot studies only involved these projects. (USGS)

Stiltner, G. J.

1990-01-01

301

Mathematical Geology  

ERIC Educational Resources Information Center

Geomathematics is a developing field that is being used in practical applications. Classification is an important element and the dynamic-cluster method (DCM), a nonhierarchial procedure, was introduced this past year. A method for testing the degree of cluster distinctness was developed also. (MA)

Merriam, Daniel F.

1978-01-01

302

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.

303

Mass Wasting and Ground Collapse in Terrains of Volatile-Rich Deposits as a Solar System-Wide Geological Process: The Pre-Galileo View  

NASA Technical Reports Server (NTRS)

The polar terrains of Mars are covered in many places with irregular pits and retreating scarps, as are some of the surfaces of the outer-planet satellites. These features are interpreted by us as diagnostic of exogenic degradation due to the loss of a volatile rock-forming matrix or cement. In this study we propose that sublimation degradation is a plausible Solar Systemwide geological process. Candidate examples have been identified on Mars, Io, and Triton, and possibly Europa and Ganymede. We envision this process as having two end-member expressions (pits and scarps), for which we hypothesize two end-member mechanisms (massive localized lenses and areally extensive basal layers). In this study we focus on the role this process may play on the surfaces of the galilean satellites. Our principle modeling results are that for these satellites, H2S, CO2, and NH3 are the only viable candidate volatiles for sublimation degradation of landforms, in light of galilean satellite cosmochemistry. For Io's polar regions only H2S, and then only from slopes that face the Sun and have thin lags, is volatile enough to cause the observed sublimation-induced erosion at those latitudes. SO2 is not a viable candidate as an agent of erosion, especially for these polar landforms. In the case of Europa, only CO2 and H2S are viable candidates (given surface age constraints). Both species could be efficient eroders in nonpolar regions. H2S could generate erosion within the polar regions if the deposition and erosion conditions were essentially identical as those we invoked for Io's polar regions. For Ganymede (and Callisto) NH3 might be an agent of erosion in equatorial terrains of great age. The sublimation of CO2 and H2S is much more robust than NH3. The much slower rate of sublimation degradation from NH3 might be detectable by Galileo and used as a compositional indicator.

Moore, Jeffrey M.; Mellon, Michael T.; Zent, Aaron P.

1996-01-01

304

Geologic exploration of solar system  

Microsoft Academic Search

The processes that must have operated on the early Earth have been deduced from evidence from ancient surfaces of the Moon and planets. In particular, such comparative studies have demonstrated that only two geologic processes have been widespread throughout the history of the solar system: impact cratering and volcanism. Impact craters have formed throughout solar system history, indeed the planets

Wood

1987-01-01

305

Geologic Maps and Mapping  

NSDL National Science Digital Library

This portal provides access to resources on geologic mapping, and to sources of geologic maps. There is an introduction to geologic mapping, which summarizes its principles and practices, and a history of United States Geological Survey (USGS) mapping activities from 1879 to the present, as well as links to papers on the values and hazards associated with geologic maps and mapping. Online sources of maps include the USGS Geologic Map Database, other federal map products (FEDMAP), state geological survey products (STATEMAP), and university map products (EDMAP).

306

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

307

GeoTemp™ 1.0: A MATLAB-based program for the processing, interpretation and modelling of geological formation temperature measurements  

NASA Astrophysics Data System (ADS)

The evaluation of potential and resources during geothermal exploration requires accurate and consistent temperature characterization and modelling of the sub-surface. Existing interpretation and modelling approaches of 1D temperature measurements are mainly focusing on vertical heat conduction with only few approaches that deals with advective heat transport. Thermal regimes are strongly correlated to rock and fluid properties. Currently, no consensus exists for the identification of the thermal regime and the analysis of such dataset. We developed a new framework allowing the identification of thermal regimes by rock formations, the analysis and modelling of wireline logging and discrete temperature measurements by taking into account the geological, geophysical and petrophysics data. This framework has been implemented in the GeoTemp software package that allows the complete thermal characterization and modelling at the formation scale and that provides a set of standard tools for the processing wireline and discrete temperature data. GeoTempTM operates via a user friendly graphical interface written in Matlab that allows semi-automatic calculation, display and export of the results. Output results can be exported as Microsoft Excel spreadsheets or vector graphics of publication quality. GeoTemp™ is illustrated here with an example geothermal application from Western Australia and can be used for academic, teaching and professional purposes.

Ricard, Ludovic P.; Chanu, Jean-Baptiste

2013-08-01

308

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

309

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

310

Constraints from Field Geology for Numerical Modeling of the Crustal Overturn Processes During the Cretaceous High-Magma-Flux Episode in the Central and Southern Sierra Nevada, USA  

NASA Astrophysics Data System (ADS)

Building on prior studies, recent fieldwork combined with geochronology, thermobarometry and geochemistry studies in the Cretaceous Sierra Nevada arc reveal the following arc-scale features: 1) The Middle to Late Cretaceous Sierra Nevada arc has a 30-35 km thick granodioritic to tonalitic upper-middle crust and may have had up to 30-35 km of mafic to ultramafic lower crust, including dehydrated amphibolitic residues. 2) Plutons emplaced during the ~20 myr long High-Magma-Flux Episode (HMFE, 105-85 Ma) include large batholiths (~1000 km2 at exposure level) with growth histories occurring over millions of years (e.g. ~9 myr for Tuolumne Batholith). Magma pulses creating such large intrusions could vary from up to 103 km3 in dimension depending on different growth models. 3) In the central Sierra Nevada, emplacement depths of the granitoid plutons during the HMFE are 7-15 km with shallow emplaced plutons’ solidi at usually ~700 -760 °C. 4) Plutons intruding only slightly older volcanic host rocks in the central and southern Sierra Nevada indicate that host rocks’ downward displacement of ~7-25 km depths occurred within 1-3 myr. This process is accompanied with the long-lived arc exhumation since at least middle Jurassic. 5) Steep syn-emplacement subsolidus lineations, rim monoclines, and plastic shear strain in pluton aureoles suggest ductile deformations of host rock materials. 6) Partial melting occurred along the margins of plutons and in the middle-lower crust, as represented in the more deeply exposed southern Sierra (30-45 km). 7) Magmatic to subsolidus foliations in plutons and ductile shear zones in host rocks indicate NW-trending transpressional tectonics during the HMFE. 8) Isotopic oxygen data and mass balance calculation indicate that crustal components provides more than 50% of the entire arc’s mass. Intra-crustal magma sources of the HMFE are sustained possibly by thickened crust due to contractional tectonics. These observations in the central and southern Sierra Nevada allow us to apply the MILAMIN_VEP, a thermo-mechanical marker-in-cell visco-elasto-plastic finite element code, to simulate more realistic scenarios of arc-scale material exchange processes. The code deals with continuous changes of density, water content, and partial melting conditions of lithosphere rocks based on calculated thermodynamic phase diagrams of differential rock types (using Perple_X). The model also takes the central Andes as a possible modern analogy for the Cretaceous Sierra Nevada. Seismic lithospherical structures, geothermal gradient, and other geological constraints are considered in the model. Aiming to yield geologically and geophysically testable results, the simulations test the hypothesis of host rock downward flow or crustal overturn processes during the HMFE, transpressional tectonics and exhumation, and to shed light on the mechanisms and controlling factors of the downward flow processes.

Cao, W.; Paterson, S. R.; Kaus, B. J.; Anderson, J. L.; Memeti, V.

2010-12-01

311

Applications of Synthetic Aperture Radar Images to Map Geologic Structures and Geomorphology: Evaluating the Interaction of Tectonic and Surface Processes in the Saint Elias Mountains, Alaska  

Microsoft Academic Search

The Saint Elias Mountains of southern Alaska and Canada are forming by collision of an allochthonous terrane at the northeastern end of the Aleutian subduction zone. The region represents one of the most dynamic glacial and tectonic systems on earth. Remote sensing is an important tool for interpreting structural and geomorphic features and processes in this remote and glaciated region

R. L. Bruhn; A. L. Ford; R. R. Forster

2004-01-01

312

Femtosecond spectroscopy of bacterial photosynthesis--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.

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

1996-04-01

313

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

314

In vitro import of cytochrome c peroxidase into the intermembrane space: release of the processed form by intact mitochondria  

PubMed Central

Cytochrome c peroxidase (CCP) is a nuclearly encoded hemoprotein located in the intermembrane space (IMS) of Saccharomyces cerevisiae mitochondria. Wild-type preCCP synthesized in rabbit reticulocyte lysates, however, was inefficiently translocated into isolated mitochondria and was inherently resistant to externally added proteases. To test whether premature heme addition to the apoprecursor was responsible for the protease resistance and the inability to import preCCP, site-directed mutagenesis was used to replace the axial heme ligand (His175) involved in forming a pseudo-covalent link between the heme iron and CCP. Mutant proteins containing Leu, Arg, Met, or Pro at residue 175 of mature CCP were sensitive to proteolysis and were imported into isolated mitochondria as judged by proteolytic processing of the precursor. The inhibition of wild-type CCP translocation across the outer membrane may result from the inability of the heme-containing protein to unfold during the translocation process. Although the protease responsible for cleaving preCCP to its mature form is believed to be located in the IMS, most of the processed CCP was located in the supernatant rather than the mitochondrial pellet. Since the outer membranes were shown to be intact, the anomalous localization indicated that preCCP may not have been completely translocated into the IMS before proteolytic processing or that conformationally labile proteins may not be retained by the outer membrane. Proteolytic maturation of preCCP also occurred in the presence of valinomycin, suggesting that the precursor may be completely or partially translocated across the outer mitochondrial membrane independent of a potential across the inner mitochondrial membrane.

1989-01-01

315

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

316

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

317

Venus geology  

NASA Astrophysics Data System (ADS)

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.

1991-05-01

318

Kentucky Geological Survey  

NSDL National Science Digital Library

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

1997-01-01

319

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

320

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

321

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

322

Characterizing Geological Behavior based in Knowledge Acquisition  

Microsoft Academic Search

Generally, petroleum data sets are characterized by high noise, missing values and several geological considerations by experts. In this work, only the porosity and spatial informa- tion is used to describe permeability (an important attribute for petroleum geology) and to acquire knowledge using petroleum data sets. Three different scenarios using six well logs are sug- gested. The objective is to

Luis Carlos Molina; Solange Oliveira Rezende

323

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

National Technical Information Service (NTIS)

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 ...

A. E. Gibbs B. M. Richmond S. A. Cochran

2008-01-01

324

Geologic Resource Evaluation of Pu'uhonua O Honaunau National Historical Park, Hawaii: Part I. Geology and Coastal Landforms.  

National Technical Information Service (NTIS)

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. Parkspecific geologic reports are used to identify g...

A. E. Gibbs B. M. Richmond S. A. Cochran

2008-01-01

325

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

326

Geologic spatial analysis  

SciTech Connect

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

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

1989-01-01

327

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

328

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

329

What is Geologic Time?  

NSDL National Science Digital Library

This USGS site employs graphics and text to explain geological time. The different geological eons, eras, epochs and periods are defined and put into perspective. The site also provides links to many terms and concepts for further exploration.

Usgs

330

South Carolina Geological Survey  

NSDL National Science Digital Library

The South Carolina Geological Survey (SCGS) homepage contains information about state mapping, education and outreach programs, and recent news. For educators, there is the Earth Science education series of publications which includes presentations and page-size graphics on such topics as earthquakes, plate tectonics, geologic time, fossils, and others. Other materials include information on mineral resources, links to organizations in and about South Carolina geology, the South Carolina core repository, the Geologic Map of South Carolina, and others.

331

Iowa Geological Survey Bureau  

NSDL National Science Digital Library

The Iowa Geological Survey Bureau (GSB) homepage contains: general information about the geology of Iowa; the Natural Resources Geographic Information System, which is a collection of databases on geology and water wells; and information about GSB staff, geologic studies, water monitoring programs, and services. There are maps, photographs, general interest articles, technical abstracts, lists of available publications, and an on-line book about the natural resource history of Iowa.

332

Relative Geologic Time and the Geologic Time Scale  

NSDL National Science Digital Library

Students are given a short introduction to fossils, strata, Steno's law of superposition, and the development of the geologic time scale from initial description of systems, through the realization that fossils could be used to correlate between systems, to the assembly of the modern geologic time scale. Then, each student in the course is given a sheet of paper with a simple stratigraphic column and associated fossils representing a geologic system on one side and a short description of the location and history of discovery of the system on the other. On a large wall, students then assemble four geologic columns from their systems representing mainland Europe, Great Britain, the Eastern U.S. and the Western U.S. using the fossils illustrated on their sheets to correlate systems. The instructor guides this process by placing the first system on the wall and by providing some narration as the columns take shape. Europe and Great Britain are assembled first, one sheet at a time, providing when completed the framework of the modern geologic time scale. Once this is up on the wall, the remaining students can assemble the other two columns in minutes using fossils to correlate between American and European systems. A temporal gap in the Grand Canyon sequence provides an opportunity to discuss the incompleteness of the rock record in any one place and a system composed of igneous and metamorphic rocks with no fossils is used to point out the difference between radiometric (absolute) and biostratigraphic (relative) dating.

Bennington, Bret

333

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.

334

Geological rhythms and cometary impacts  

NASA Technical Reports Server (NTRS)

Time series analysis reveals two dominant, long-term periodicities approximately equal to 32 and 260 million years in the known series of geological and biological upheavals during the Phanerozoic Eon. The cycles of these episodes agree in period and phase with the cycles of impact cratering on Earth, suggesting that periodic comet impacts strongly influence Earth processes.

Rampino, M. R.; Strothers, R. B.

1984-01-01

335

Geological Survey Program  

NSDL National Science Digital Library

If your research or interests lie in the geology of South Dakota, then the state's Geological Survey Program Web site is for you. Offered are online publications and maps, a geologic reference database, a lithologic logs database, digital base maps, a water quality database, and several other quality information sources worth checking out.

336

A Geological Wonder: Niagara Falls  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 9-12. It focuses on the geological history of the Niagara Falls area, as well as the physical and geological processes that have formed this region. It includes objectives, materials, procedures, discussion questions, evaluation ideas, performing extensions, suggested readings, and vocabulary. There are videos available to order which complement this lesson, audio vocabulary, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

337

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

338

Geological age of reactors  

NASA Astrophysics Data System (ADS)

Nuclear reactors become obsolete by wearing out or by becoming outclassed or out of date. The lifetime of a conventional power reactor is probably less that 30 years, but the life of its potentially dangerous radioactivity is now known to be of a geological time scale. When a reactor is shutdown permanently, the fuel rods, cooling water, and radioactively ‘hot’ pieces are removed for long-term storage. High-level and low-level radioactive isotopes contained in the liquids and solids removed present a special problem (see Eos, Feb. 9, 1982, p. 147). It is the main frame and construction of worn out reactors that are the major problem, however. Mainly because of neutron activation processes that occur during reactor operation, components have been found to contain nickel-59 and niobium-94, both of which have very long half-lives: 80,000 and 20,300 years, respectively. The two isotopes are only present in trace amounts in metals incorporated in reactor components, but they emit levels of radiation above acceptable levels. The result is that the entire reactors must be dismantled, reduced to shippable size pieces, and the pieces stored for geologic time periods (several half-lives).

Bell, Peter M.

339

Arkansas Geological Survey  

NSDL National Science Digital Library

The Arkansas Geological Survey (AGS) homepage aims to develop and provide knowledge of the geology and hydrogeology of the State, and to stimulate development and effective management and utilization of the mineral, fossil-fuel, and water resources of Arkansas while protecting the environment. The AGC collects and disperses geologic data consisting of geologic maps, historical data concerning resources, and various datasets concerning water, fossil-fuel, and mineral resources of Arkansas. The site contains publications that can be ordered, sections about Arkansas geology, a list of mineral producers of Arkansas, and reports on mineral resources.

340

Virtual-Geology.Info  

NSDL National Science Digital Library

At virtual-geology.info, Roger Suthren, a professor at Oxford Brookes University, offers educational materials on geologic phenomena throughout the world. Users can take virtual field trips to study the geology of Scotland, Alaska, and France. In the Regional Geology link, visitors can view wonderful pictures of the volcanoes of Germany, Italy, France, and Greece. Educators can find images of sediments and sedimentary rocks which can be used in a variety of classroom exercises. The website supplies descriptions and additional educational links about sedimentology and environmental geology.

341

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.

342

Geology for a changing world 2010-2020-Implementing the U.S. Geological Survey science strategy  

USGS Publications Warehouse

This report describes a science strategy for the geologic activities of the U.S. Geological Survey (USGS) for the years 2010-2020. It presents six goals with accompanying strategic actions and products that implement the science directions of USGS Circular 1309, 'Facing Tomorrow's Challenges-U.S. Geological Survey Science in the Decade 2007-2017.' These six goals focus on providing the geologic underpinning needed to wisely use our natural resources, understand and mitigate hazards and environmental change, and understand the relationship between humans and the environment. The goals emphasize the critical role of the USGS in providing long-term research, monitoring, and assessments for the Nation and the world. Further, they describe measures that must be undertaken to ensure geologic expertise and knowledge for the future. The natural science issues facing today's world are complex and cut across many scientific disciplines. The Earth is a system in which atmosphere, oceans, land, and life are all connected. Rocks and soils contain the answers to important questions about the origin of energy and mineral resources, the evolution of life, climate change, natural hazards, ecosystem structures and functions, and the movements of nutrients and toxicants. The science of geology has the power to help us understand the processes that link the physical and biological world so that we can model and forecast changes in the system. Ensuring the success of this strategy will require integration of geological knowledge with the other natural sciences and extensive collaboration across USGS science centers and with partners in Federal, State, and local agencies, academia, industry, nongovernmental organizations and, most importantly, the American public. The first four goals of this report describe the scientific issues facing society in the next 10 years and the actions and products needed to respond to these issues. The final two goals focus on the expertise and infrastructure needed to ensure the long-term sustainability of the geological sciences in the USGS. The ultimate goal of USGS science and of the strategy laid out in this document is to contribute to the development of a sustainable society that operates in harmony with the Earth systems that society depends upon. As we begin the second decade of the 21st century, our Nation faces growing challenges in resource availability, climate and environmental change, and natural hazards. Meeting these challenges will require strong collaboration across the natural and social sciences and extensive partnerships with both the public and private sectors. The six goals described in this document represent a mix of scientific focus areas and operational necessities that together provide a comprehensive roadmap for USGS geologic science to effectively contribute to the USGS mission, providing science for a changing world.

Gundersen, Linda C.S.; Belnap, Jayne; Goldhaber, Martin; Goldstein, Arthur; Haeussler, Peter J.; Ingebritsen, S.E.; Jones, John W.; Plumlee, Geoffrey S.; Thieler, E. Robert; Thompson, Robert S.; Back, Judith M.

2011-01-01

343

Ohio Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Ohio Geological Survey. Materials available through the site include a variety of publications, particularly the Survey's reports, bulletins, information circulars, guidebooks, and many others. There is an extensive selection of maps, including topographic maps in several scales, and downloadable geologic maps of several themes (drift thickness, bedrock geology, karst areas, glacial geology, and many others), as well as digital maps and data. The interactive maps section features online map viewers of abandoned mines, earthquake epicenters, surficial geology, geology of Lake Erie, and others. The educational resources page has links to the 'Hands On Earth' series of activities, GeoFacts (short bulletins on Ohio geological topics), nontechnical educational leaflets, field guides, and links to other publications, rock and mineral clubs, educational associations, and related websites. There is also a link to the Ohio Seismic Network, a network of seismograph stations located at colleges, universities, and other institutions that collects and disseminates information about earthquakes in Ohio.

344

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.

345

Processing of Human Cytomegalovirus UL37 Mutant Glycoproteins in the Endoplasmic Reticulum Lumen prior to Mitochondrial Importation  

PubMed Central

The human cytomegalovirus (HCMV) UL37 glycoprotein (gpUL37) is internally cleaved and its products divergently traffic to mitochondria or are retained in the secretory pathway. To define the requirements for gpUL37 cleavage, residues ?1 and ?3 of the consensus endoplasmic reticulum (ER) signal peptidase I site within exon 3 (UL37x3) were replaced by bulky tyrosines (gpUL37 cleavage site mutant I). Internal cleavage of this UL37x3 mutant was inhibited, verifying usage of the consensus site at amino acids (aa) 193/194. The full-length mitochondrial species of gpUL37 cleavage site mutant I was N glycosylated and endoglycosidase H sensitive, indicating that ER translocation and processing took place prior to its mitochondrial importation. Moreover, these results suggest that internal cleavage of gpUL37 is not necessary for its N glycosylation. Partial deletion or disruption of the UL37 hydrophobic core immediately upstream of the cleavage site resulted in decreased protein abundance, suggesting that the UL37x3 hydrophobic ?-helix contributes to either correct folding or stability of gpUL37. Insertion of the UL37x3 hydrophobic core and cleavage site into pUL37M, a splice variant of gpUL37 which lacks these sequences and is neither proteolytically cleaved nor N glycosylated, resulted in its internal cleavage and N glycosylation. Its NH2-terminal fragment, pUL37M-NH2, was detected more abundantly in mitochondria, while its N-glycosylated C-terminal fragment, gpUL37M-COOH, was detected predominantly in the ER in a manner analogous to that of gpUL37 cleavage products. These results indicate that UL37x3 aa 178 to 205 are prerequisite for gpUL37 internal cleavage and alter UL37 protein topology allowing N glycosylation of its C-terminal sequences. In contrast, the NH2-terminal UL37x1 hydrophobic leader, present in pUL37x1, pUL37M, and gpUL37, is not cleaved from mature UL37 protein, retaining a membrane anchor for UL37 isoforms during trafficking. Taken together, these results suggest that HCMV gpUL37 undergoes sequential trafficking, during which it is ER translocated, processed, and then mitochondrially imported.

Mavinakere, Manohara S.; Williamson, Chad D.; Goldmacher, Victor S.; Colberg-Poley, Anamaris M.

2006-01-01

346

Rheology and density of glucose syrup and honey: Determining their suitability for usage in analogue and fluid dynamic models of geological processes  

NASA Astrophysics Data System (ADS)

Analogue models of lithospheric deformation and fluid dynamic models of mantle flow mostly use some kind of syrup such as honey or glucose syrup to simulate the low-viscosity sub-lithospheric mantle. This paper describes detailed rheological tests and density measurements of three brands of glucose syrup and three brands of honey. Additional tests have been done for one brand of glucose syrup that was diluted with water to various degrees (2%, 5% and 10% by weight). The rheological tests have been done to test the effect of shear strain, shear rate and temperature on the dynamic viscosity of the syrup. The results show that the viscosity of all glucose syrups and honeys is independent of shear strain (i.e. no strain hardening or softening). The viscosity of the glucose syrups is independent of shear rate (??), i.e. linear-viscous or Newtonian, in the range ??=10-4-10 s with stress exponents that are almost identical to one ( n = 0.995-1.004). All the honeys show a very weak, but consistent, decrease in viscosity with increasing shear rate of 7-14% from 10 -3 to 10 0 s -1 and have stress exponents more distinct from one ( n = 1.007-1.026). All syrups have a viscosity that is strongly dependent on temperature in the range 0-50 °C, where viscosity decreases with increasing temperature. Such decrease can be fitted with exponential and Arrhenius functions, with the latter giving the best results. Furthermore, the viscosity of glucose syrup decreases approximately exponentially with increasing water content. Oscillation tests indicate that the rheology of all the syrups is entirely dominated by viscous behaviour and not by elastic behaviour at frequencies of 10 -3-10 2 Hz. Finally, the density investigations show that the density of glucose syrup and honey decreases approximately linearly with increasing temperature in the range 10-70 °C, with coefficients of thermal volumetric expansion at 20 °C of 3.89-3.95 × 10 -4 °C -1 and 4.57-4.81 × 10 -4 °C -1 for glucose syrup and honey, respectively. The new results demonstrate that glucose syrups and (to a lesser degree) honeys are well suited for usage in analogue and fluid dynamic experiments to represent linear-viscous strain independent and shear rate independent rheologies to model geological processes. Glucose syrups have the added advantage of being more transparent than honeys, allowing for accurately resolving and quantifying flow patterns in the fluid during a model run.

Schellart, W. P.

2011-06-01

347

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 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 surface 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 one of the four 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 the USA and experimental data from plot-scale rainfall-simulation experiments at the University of Tsukuba Large Rainfall-Simulation Facility are 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, C. J.; Wainwright, J.; Parsons, A. J.; Cooper, J. R.; Kitchener, B.; Hargrave, G. K.; Long, E. J.; Onda, Y.; Patin, J.

2013-12-01

348

Modulation of Transporter Associated with Antigen Processing (TAP)-Mediated Peptide Import into the Endoplasmic Reticulum by Flavivirus Infection  

PubMed Central

In contrast to many other viruses that escape the cellular immune response by downregulating major histocompatibility complex (MHC) class I molecules, flavivirus infection can upregulate their cell surface expression. Previously we have presented evidence that during flavivirus infection, peptide supply to the endoplasmic reticulum is increased (A. Müllbacher and M. Lobigs, Immunity 3:207–214, 1995). Here we show that during the early phase of infection with different flaviviruses, the transport activity of the peptide transporter associated with antigen processing (TAP) is augmented by up to 50%. TAP expression is unaltered during infection, and viral but not host macromolecular synthesis is required for enhanced peptide transport. This study is the first demonstration of transient enhancement of TAP-dependent peptide import into the lumen of the endoplasmic reticulum as a consequence of a viral infection. We suggest that the increased supply of peptides for assembly with MHC class I molecules in flavivirus-infected cells accounts for the upregulation of MHC class I cell surface expression with the biological consequence of viral evasion of natural killer cell recognition.

Momburg, Frank; Mullbacher, Arno; Lobigs, Mario

2001-01-01

349

Geological consequences of superplumes  

SciTech Connect

Superplumes are suggested to have caused the period of constant normal magnetic polarity in mid-Cretaceous time (124-83 Ma) and, possibly, the period of constant reversed polarity in Pennsylvania-Permian time (323-248 Ma). These times coincide with increases in world temperature, deposition of black shales, oil generation, and eustatic sea level in the mid-Cretaceous, and increased coal generation and gas accumulation in the Pennsylvanian-Permian, accompanied by an intracratonic Pennsylvanian transgression of epicontinental seas. These geologic anomalies are associated with episodes of increased world-wide ocean-crust production and mantle outgassing, especially of carbon and nutrients. These superplumes originated just above the core-mantle boundary, significantly increased convection in the outer core, and stopped the magnetic field reversal process for 41 m.y. in the Cretaceous and 75 m.y. in Pennsylvanian-Permian time.

Larson, R.L. (Univ. of Rhode Island, Narragansett (United States))

1991-10-01

350

Geological consequences of superplumes  

NASA Astrophysics Data System (ADS)

Superplumes are suggested to have caused the period of constant normal magnetic polarity in mid-Cretaceous time (124-83 Ma) and, possibly, the period of constant reversed polarity in Pennsylvanian-Permian time (323-248 Ma). These times coincide with increases in world temperature, deposition of black shales, oil generation, and eustatic sea level in the mid-Cretaceous, and increased coal generation and gas accumulation in the Pennsylvanian-Permian, accompanied by an intracratonic Pennsylvanian transgression of epicontinental seas. These geologic anomalies are associated with episodes of increased world-wide ocean-crust production and mantle outgassing, especially of carbon and nutrients. These superplumes originated just above the core-mantle boundary, significantly increased convection in the outer core, and stopped the magnetic field reversal process for 41 m.y. in the Cretaceous and 75 m.y. in Pennsylvanian-Permian time.

Larson, Roger L.

1991-10-01

351

Differentiating the relative importance of land cover change and geomorphic processes on fine sediment sequestration in a logged watershed  

NASA Astrophysics Data System (ADS)

Timber harvest often results in accelerated soil erosion and subsequent elevated fine (< 2 mm) sediment delivery to channels causing deleterious effects to numerous aquatic species, particularly salmonid fishes. Here we determine, through sediment physical analyses (pebble counts, embeddedness surveys, and interstitial shelter space counts) and geochemical analyses (7Be and 210Pbex activities), the amount and timing of delivery of fine sediment currently found on streambeds of the Narraguagus River watershed in coastal Maine. The role of recent timber harvest, documented via aerial photo spatial analysis, on fine sediment delivery is contrasted with the ability of the glacially influenced topography and surficial geology to deliver fine sediment to streams and to influence channel substrate. Results show that of the land use and geomorphic variables examined, only 210Pbex activities were significantly correlated with the amount of upstream harvest (r2 = 0.49). Concurrently, we find that unit stream power (particularly the slope component) explains much of the variability in channel substrate and that slope and stream power are largely influenced by the legacy of Pleistocene glaciation on channel form. Results suggest a conceptual model whereby fine sediment delivery as a result of late twentieth century timber harvest is likely dampened because of the low gradient landscape of coastal Maine. While geochemical tracers indicate recent fine sediment delivery in harvested areas, channels are likely capable of quickly winnowing these fines from the channel bed. These results further suggest that under contemporary land use conditions, the geomorphic and geologic setting represents a first-order control on channel substrate and habitat suitability for salmonid fishes, including federally endangered Atlantic salmon (Salmo salar), in coastal drainages of northeastern Maine.

Kasprak, Alan; Magilligan, Francis J.; Nislow, Keith H.; Renshaw, Carl E.; Snyder, Noah P.; Dade, W. Brian

2013-03-01

352

Construction of opening regional geological hazards risk assessment system  

NASA Astrophysics Data System (ADS)

It's the basis of the regional geological hazard assessment of regional geological hazard risk research, and the result can provide foundation for planning of land and resources, selection of important project site, controlling, monitoring, and forecasting geological disaster, developing contingency measures for disaster, and environmental protection. With the development of GIS technology, methods and models of regional geological hazard assessment have made great progress, it gradually change from the qualitative and semi-quantitative to quantitative, systematic, spatial management. This paper proposed a user-oriented, method- oriented, category-oriented system of regional geological hazards risk assessment through discusses the key points of geological hazards risk assessment, and the requirements of geological disaster evaluation system development today. The new evaluation system fit varieties types of geological disaster evaluation in different areas, and it owns a very important practical significance.

Zhu, Jixiang; Zhang, Lizhong; Zhou, Xiaoyuan; Wang, Qian

2011-10-01

353

Geologic setting of serpentine deposits on Mars  

NASA Astrophysics Data System (ADS)

Serpentine, recently discovered on Mars using Mars Reconnaissance Orbiter data, is uncommon but found in three geologic settings: (1) in mélange terrains at the Claritas Rise and the Nili Fossae, (2) associated with a few southern highlands impact craters, and (3) associated with a regional olivine-rich stratigraphic unit near the Isidis basin. Any presently active serpentinization processes would be occurring beneath the surface and mineral products would not be apparent with surface and orbital data; however, finding serpentine in several Noachian terrains indicates active serpentinization processes in Mars' past. Important implications are the past production of magnetite, which may contribute to chemical remnant magnetization of Mars' crust, and production of H2, which is a suitable energy source for chemosynthetic microbial life.

Ehlmann, B. L.; Mustard, J. F.; Murchie, S. L.

2010-03-01

354

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

355

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

356

An Exploratory Study of the Importance of Sustainable Practices in the Meeting and Convention Site Selection Process  

Microsoft Academic Search

The purpose of this exploratory study was to develop a list of sustainable practices at convention facilities and assess the importance of these items according to meeting planners. The recycling of items had the highest levels of importance. Significant differences were found between third party and association meeting planners’ levels of importance in the areas of water resources, energy efficiency,

Jason Draper; Mary Dawson; Emma Casey

2011-01-01

357

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

SciTech Connect

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

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

1984-02-14

358

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.

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

2010-01-01

359

Harmonisation of geological data to support geohazard mapping: the case of eENVplus project  

NASA Astrophysics Data System (ADS)

In the eENVplus project, which aims is to unlock huge amounts of environmental datamanaged by the national and regional environmental agencies and other public and private organisations, we have developed a cross-border pilot on the geological data harmonisation through the integration and harmonisation of existing services. The pilot analyses the methodology and results of the OneGeology-Europe project, elaborated at the scale of 1:1M, to point out difficulties and unsolved problems highlighted during the project. This preliminary analysis is followed by a comparison of two geological maps provided by the neighbouring countries with the objective to compare and define the geometric and semantic anomalous contacts between geological polygons and lines in the maps. This phase will be followed by a detailed scale geological map analysis aimed to solve the anomalies identified in the previous phase. The two Geological Surveys involved into the pilot will discuss the problems highlighted during this phase. Subsequently the semantic description will be redefined and the geometry of the polygons in geological maps will be redrawn or adjusted according to a lithostratigraphic approach that takes in account the homogeneity of age, lithology, depositional environment and consolidation degree of geological units. The two Geological Surveys have decided to apply the harmonisation process on two different dataset: the first is represented by the Geological Map at the scale of 1:1,000,000, partially harmonised within the OneGeology-Europe project that will be re-aligned with GE INSPIRE data model to produce data and services compliant with INSPIRE target schema. The main target of Geological Surveys is to produce data and web services compliant with the wider international schema, where there are more options to provide data, with specific attributes that are important to obtain the geohazard map as in the case of this pilot project; therefore we have decided to apply GeoSciML 3.2 schema to the dataset that represents Geological Map at the scale of 1:100,000. Within the pilot will be realised two main geohazard examples with a semi-automatized procedure based on a specific tool component integrated in the client: a landslide susceptibility map and a potential flooding map. In this work we want to present the first results obtained with use case geo-processing procedure in the first test phase, where we have developed a dataset compliant with GE INSPIRE to perform the landslide and flooding susceptibility maps.

Cipolloni, Carlo; Krivic, Matija; Novak, Matevž; Pantaloni, Marco; Šinigoj, Jasna

2014-05-01

360

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

361

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

362

Geologic Time: Online Edition  

NSDL National Science Digital Library

Offered by the United States Geological Survey (USGS) as a general interest publication, this site is an online edition of a text by the same name, offering a concise overview of the concepts associated with the age of the Earth. The online edition was revised in October of 1997 to reflect current thinking on this topic. Section headers are Geologic Time, Relative Time Scale, Major Divisions of Geologic Time, Index Fossils, Radiometric Time Scale, and Age of the Earth.

1997-10-09

363

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

364

North Carolina Geological Survey  

NSDL National Science Digital Library

The North Carolina Geological Survey (NCGS) examines, describes, and maps the state's geology and mineral resources and publishes reports and maps. The site contains lists of publications, maps, aerial photographs, frequently asked questions about North Carolina geology, and mineral and professional information. Project Earth Science is designed to provide relevant and accurate earth science education information for the state's high school students and earth/environmental science teachers.

365

What is the importance of climate model bias when projecting the impacts of climate change on land surface processes?  

NASA Astrophysics Data System (ADS)

Regional climate change impact (CCI) studies have widely involved downscaling and bias correcting (BC) global climate model (GCM)-projected climate for driving land surface models. However, BC may cause uncertainties in projecting hydrologic and biogeochemical responses to future climate due to the impaired spatiotemporal covariance of climate variables and a breakdown of physical conservation principles. Here we quantify the impact of BC on simulated climate-driven changes in water variables (evapotranspiration (ET), runoff, snow water equivalent (SWE), and water demand for irrigation), crop yield, biogenic volatile organic compounds (BVOC), nitric oxide (NO) emissions, and dissolved inorganic nitrogen (DIN) export over the Pacific Northwest (PNW) region. We also quantify the impacts on net primary production (NPP) over a small watershed in the region (HJ-Andrews). Simulation results from the coupled ECHAM5-MPI-OM model with A1B emission scenario were first dynamically downscaled to 12 km resolution with the WRF model. Then a quantile-mapping-based statistical downscaling model was used to downscale them into 1/16° resolution daily climate data over historical and future periods. Two climate data series were generated, with bias correction (BC) and without bias correction (NBC). Impact models were then applied to estimate hydrologic and biogeochemical responses to both BC and NBC meteorological data sets. These impact models include a macroscale hydrologic model (VIC), a coupled cropping system model (VIC-CropSyst), an ecohydrological model (RHESSys), a biogenic emissions model (MEGAN), and a nutrient export model (Global-NEWS). Results demonstrate that the BC and NBC climate data provide consistent estimates of the climate-driven changes in water fluxes (ET, runoff, and water demand), VOCs (isoprene and monoterpenes) and NO emissions, mean crop yield, and river DIN export over the PNW domain. However, significant differences rise from projected SWE, crop yield from dry lands, and HJ-Andrews's ET between BC and NBC data. Even though BC post-processing has no significant impacts on most of the studied variables when taking PNW as a whole, their effects have large spatial variations and some local areas are substantially influenced. In addition, there are months during which BC and NBC post-processing produces significant differences in projected changes, such as summer runoff. Factor-controlled simulations indicate that BC post-processing of precipitation and temperature both substantially contribute to these differences at regional scales. We conclude that there are trade-offs between using BC climate data for offline CCI studies versus directly modeled climate data. These trade-offs should be considered when designing integrated modeling frameworks for specific applications; for example, BC may be more important when considering impacts on reservoir operations in mountainous watersheds than when investigating impacts on biogenic emissions and air quality, for which VOCs are a primary indicator.

Liu, M.; Rajagopalan, K.; Chung, S. H.; Jiang, X.; Harrison, J.; Nergui, T.; Guenther, A.; Miller, C.; Reyes, J.; Tague, C.; Choate, J.; Salathé, E. P.; Stöckle, C. O.; Adam, J. C.

2014-05-01

366

What is the importance of climate model bias when projecting the impacts of climate change on land surface processes?  

NASA Astrophysics Data System (ADS)

Regional climate change impact (CCI) studies have widely involved downscaling and bias-correcting (BC) Global Climate Model (GCM)-projected climate for driving land surface models. However, BC may cause uncertainties in projecting hydrologic and biogeochemical responses to future climate due to the impaired spatiotemporal covariance of climate variables and a breakdown of physical conservation principles. Here we quantify the impact of BC on simulated climate-driven changes in water variables (evapotranspiration, ET; runoff; snow water equivalent, SWE; and water demand for irrigation), crop yield, biogenic volatile organic compounds (BVOC), nitric oxide (NO) emissions, and dissolved inorganic nitrogen (DIN) export over the Pacific Northwest (PNW) Region. We also quantify the impacts on net primary production (NPP) over a small watershed in the region (HJ Andrews). Simulation results from the coupled ECHAM5/MPI-OM model with A1B emission scenario were firstly dynamically downscaled to 12 km resolutions with WRF model. Then a quantile mapping based statistical downscaling model was used to downscale them into 1/16th degree resolution daily climate data over historical and future periods. Two series climate data were generated according to the option of bias-correction (i.e. with bias-correction (BC) and without bias-correction, NBC). Impact models were then applied to estimate hydrologic and biogeochemical responses to both BC and NBC meteorological datasets. These impact models include a macro-scale hydrologic model (VIC), a coupled cropping system model (VIC-CropSyst), an ecohydrologic model (RHESSys), a biogenic emissions model (MEGAN), and a nutrient export model (Global-NEWS). Results demonstrate that the BC and NBC climate data provide consistent estimates of the climate-driven changes in water fluxes (ET, runoff, and water demand), VOCs (isoprene and monoterpenes) and NO emissions, mean crop yield, and river DIN export over the PNW domain. However, significant differences rise from projected SWE, crop yield from dry lands, and HJ Andrews's ET between BC and NBC data. Even though BC post-processing has no significant impacts on most of the studied variables when taking PNW as a whole, their effects have large spatial variations and some local areas are substantially influenced. In addition, there are months during which BC and NBC post-processing produces significant differences in projected changes, such as summer runoff. Factor-controlled simulations indicate that BC post-processing of precipitation and temperature both substantially contribute to these differences at region scales. We conclude that there are trade-offs between using BC climate data for offline CCI studies vs. direct modeled climate data. These trade-offs should be considered when designing integrated modeling frameworks for specific applications; e.g., BC may be more important when considering impacts on reservoir operations in mountainous watersheds than when investigating impacts on biogenic emissions and air quality (where VOCs are a primary indicator).

Liu, M.; Rajagopalan, K.; Chung, S. H.; Jiang, X.; Harrison, J.; Nergui, T.; Guenther, A.; Miller, C.; Reyes, J.; Tague, C.; Choate, J.; Salathé, E. P.; Stöckle, C. O.; Adam, J. C.

2013-11-01

367

The GPlates Geological Information Model and Markup Language  

NASA Astrophysics Data System (ADS)

Understanding tectonic and geodynamic processes leading to the present-day configuration of the Earth involves studying data and models across a variety of disciplines, from geochemistry, geochronology and geophysics, to plate kinematics and mantle dynamics. All these data represent a 3-dimensional spatial and 1-dimensional temporal framework, a formalism which is not exploited by traditional spatial analysis tools. This is arguably a fundamental limit in both the rigour and sophistication in which datasets can be combined for geological "deep time" analysis, and often confines the extent of data analyses to the present-day configurations of geological objects. The GPlates Geological Information Model (GPGIM) represents a formal specification of geological and geophysical data in a time-varying plate tectonics context, used by the GPlates virtual-globe software. It provides a framework in which relevant types of geological data are attached to a common plate tectonic reference frame, allowing the data to be reconstructed in a time-dependent spatio-temporal plate reference frame. The GPlates Markup Language (GPML), being an extension of the open standard Geography Markup Language (GML), is both the modelling language for the GPGIM and an XML-based data format for the interoperable storage and exchange of data modelled by it. The GPlates software implements the GPGIM allowing researchers to query, visualise, reconstruct and analyse a rich set of geological data including numerical raster data. The GPGIM has recently been extended to support time-dependent geo-referenced numerical raster data by wrapping GML primitives into the time-dependent framework of the GPGIM. Coupled with GPlates' ability to reconstruct numerical raster data and import/export from/to a variety of raster file formats, as well as its handling of time-dependent plate boundary topologies, interoperability with geodynamic softwares is established, leading to a new generation of deep-time spatio-temporal data analysis and modelling, including a variety of new functionalities such as 4-D data-mining.

Qin, X.; Müller, R. D.; Cannon, J.; Landgrebe, T. C. W.; Heine, C.; Watson, R. J.; Turner, M.

2012-07-01

368

The GPlates Geological Information Model and Markup Language  

NASA Astrophysics Data System (ADS)

Understanding tectonic and geodynamic processes leading to the present-day configuration of the Earth involves studying data and models across a variety of disciplines, from geochemistry, geochronology and geophysics, to plate kinematics and mantle dynamics. All these data represent a 3-D spatial and 1-D temporal framework, a formalism which is not exploited by traditional spatial analysis tools. This is arguably a fundamental limit in both the rigour and sophistication in which datasets can be combined for geological deep time analysis, and often confines the extent of data analyses to the present-day configurations of geological objects. The GPlates Geological Information Model (GPGIM) represents a formal specification of geological and geophysical data in a time-varying plate tectonics context, used by the GPlates virtual-globe software. It provides a framework in which relevant types of geological data are attached to a common plate tectonic reference frame, allowing the data to be reconstructed in a time-dependent spatio-temporal plate reference frame. The GPlates Markup Language (GPML), being an extension of the open standard Geography Markup Language (GML), is both the modelling language for the GPGIM and an XML-based data format for the interoperable storage and exchange of data modelled by it. The GPlates software implements the GPGIM allowing researchers to query, visualise, reconstruct and analyse a rich set of geological data including numerical raster data. The GPGIM has recently been extended to support time-dependent geo-referenced numerical raster data by wrapping GML primitives into the time-dependent framework of the GPGIM. Coupled with GPlates' ability to reconstruct numerical raster data and import/export from/to a variety of raster file formats, as well as its handling of time-dependent plate boundary topologies, interoperability with geodynamic softwares is established, leading to a new generation of deep-time spatio-temporal data analysis and modelling, including a variety of new functionalities, such as 4-D data-mining.

Qin, X.; Müller, R. D.; Cannon, J.; Landgrebe, T. C. W.; Heine, C.; Watson, R. J.; Turner, M.

2012-10-01

369

Shock compression of geological materials  

NASA Astrophysics Data System (ADS)

Understanding the shock compression of geological materials is important for many applications, and is particularly important to the mining industry. During blast mining the response to shock loading determines the wave propagation speed and resulting fragmentation of the rock. The present work has studied the Hugoniot of two geological materials; Lake Quarry Granite and Gosford Sandstone. For samples of these materials, the composition was characterised in detail. The Hugoniot of Lake Quarry Granite was predicted from this information as the material is fully dense and was found to be in good agreement with the measured Hugoniot. Gosford Sandstone is porous and undergoes compaction during shock loading. Such behaviour is similar to other granular material and we show how it can be described using a P-a compaction model.

Kirk, S.; Braithwaite, C.; Williamson, D.; Jardine, A.

2014-05-01

370

Serving Bay Area Geologic Hazard Information in Google Earth KML; a Network-Link Approach  

NASA Astrophysics Data System (ADS)

We present a method to convert and provide San Francisco Bay Area geologic map information in Google Earth KML format. Google Earth software is an interactive, virtual globe that can be effective for communicating important geologic information to public and scientific audiences. The USGS, CGS, and other groups have collected a wealth of geologic information in the Bay Area, but little has been done to organize and provide this data in a single location and viewing format. Static maps and associated GIS files are the common output of such mapping efforts, but these are not easily obtained or viewed by the general public. Alternatively, geologic maps served in KML format can be downloaded from servers and viewed as overlays on the high-resolution static aerial imagery supplied by Google. Further, the software provides 3D terrain and the ability to search for a location by address or coordinates. Complex geologic maps result in large KML file sizes, which in turn, slows down network and CPU performance on the user's end. To provide for more efficiency, the method we present utilizes ESRI's ArcMap Model Builder software to automate the process of breaking a large GIS dataset into multiple KML tiles. An individual tile has the extent of a 7.5' USGS quadrangle and a file size small enough to be rapidly retrieved from a server and processed by Google Earth for viewing. A single KML file manages the visibility of all the tiles, retrieving only the necessary tile(s) to fill the field of view. We intend to use this method to present important geologic information such as bedrock geology and geologic hazard data, including liquefaction susceptibility, faults and fault zones, landslides, flood zones, and various shaking scenarios in the Bay Area.

Blair, J. L.; Ticci, M.

2006-12-01

371

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

372

Geologic Mapping Exercise  

NSDL National Science Digital Library

This exercise is designed to simulate how a basic geological investigation of a site takes place. A basic geological investigation includes familiarizing yourself with the unconsolidated sediments, rocks, structural geology, and groundwater present at your site. As part of this exercise you will have to properly identify a variety of rock types and sediments, create maps that represent data you collected at each location, and complete a basic report of your findings (optional). Once completed, this exercise should give students a basic understanding of how the various concepts used throughout the semester are applied in the real world in the form of a geological investigation.

Smith, Andrew

373

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

374

On three-dimensional geological modeling and visualization  

Microsoft Academic Search

The technology of 3D geological modeling will bring about great changes in the methods of geological data acquiring, storing,\\u000a processing and displaying. However, no perfect or convenient software systems have been developed up to now since the geologic\\u000a data which reflect geological entities bear the feature of diversity, uncertainty and complexity. Some super voxel models,\\u000a mathematical models of fault and

Qiang Wu; Hua Xu

2004-01-01

375

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

376

Geology explorer: virtual geologic mapping and interpretation  

NASA Astrophysics Data System (ADS)

We are developing internet-based freeware for virtual mapping and geologic interpretation. This takes the form of a synthetic, virtual world, Planet Oit, where students are given the means and the equipment to carry out geologic investigation and interpretation as a geologist would in the field. The environment is designed to give students an authentic experience that includes elements of: (1) exploration of a spatially oriented, virtual, world; (2) practical, field oriented, expedition planning and decision-making; and (3) scientific problem solving (i.e. a "hands on" approach to mapping, geologic investigation, data acquisition, and interpretation). The game-like environment is networked, multi-player, and simulation-based. Planet Oit can be visited on the Internet at http://oit.cs.ndsu.nodak.edu/

Saini-Eidukat, Bernhardt; Schwert, Donald P.; Slator, Brian M.

2002-12-01

377

Metamorphic and magmatic processes in the central part of the Lapland granulite belt: correlation of geological and petrological study with results of isotopic dating  

NASA Astrophysics Data System (ADS)

Based on geological and petrological study the sequence of magmatic and metamorphic events in the central part of the Lapland granulite belt (the Lotta river area, Kola Peninsula, Russia) has been reconstructed, that allows to reveal physical and chemical conditions of individual episodes in the history of the studied region, and make a correct correlation of petrological data with the results of isotopic dating. It was established that all metapelitic associations found within the studied region, are products of allochemical alterations of "felsic" quartz-feldspar granulites and embedded basic rocks. First granulite moderate-pressure metamorphism (T = 630-730°C, P = 4.0-5.7 kbar) occurred 1.97 -1.96 Ga. The crystallization temperature of metamorphic zircons of this stage (according to Ti contents) is 709-742°C - consistent with petrological data. Basic magmatism - intrusion of small bodies and dykes of gabbro and gabbro-norites took place 1.96 Ga and clearly separates two episodes of granulite facies metamorphism. Granulite HP metamorphism (780-860°C and 6.8-9.5 kbar) and syncollision diathectic S-granitoid formation occurred 1.92-1.91 Ga. The beginning of metamorphism associated with the crystallization of synmetamorphic enderbites - 1929-1925 Ma. The age of metamorphic granulite zircons is 1921-1917 Ma. Crystallization temperature of these zircons is 756-856°C, also consistent with petrological data. Polyphase inclusion in zircons: Kfs + Qtz, Kfs + Qtz + Pl and inclusion of Bt suggest that the formation of zircon occurred simultaneously with the formation of the paragenesis Grt + Bt + Pl + Sil + Qtz (± Kfs). Sm-Nd isochrone for Grt-Cpx-WR-Pl gave an age of 1918 ± 30 Ma. According to petrological data Grt and Cpx growth occurred at isothermal decompression stage with the pressure drop up to 6 kbar. Central parts of clinopyroxene contain up to 10% jadeite component and rims of about 2%. U-Pb garnet age 1925-1932 Ma coincides well with Sm-Nd garnet age. The fact that different minerals and different isotopic systems show the same ages speaks about rapid cooling, when the isotopic system closed soon after mineral formation and the obtained age is crystallization age but not cooling age. Formation of leucogranites as a result of sillimanite-garnet gneiss melting occurred at 1915 -1910 Ma. Zircons in leucogranites contain the same inclusion (Kfs, Sil and Qtz) as granulite zircons, which means, that they have been formed simultaneously with the formation of Sil and the presence of Kfs in paragenesis. Crystallization temperatures of these diathectic zircons - 801-826 ° C overlaps with the crystallization temperature of granulite zircons, as well as an age range of their crystallization. Analysis of the geochemical characteristics of zircons (content and distribution of incompatible elements) and U-Pb dating showed that the formation of granulite and diathectic zircons crystallized from the melt during the same diathectic process. Crystallization temperatures, as determined by Ti contents, are in good agreement with the metamorphic temperatures, defined by generally accepted geothermometers. Isobaric cooling to 657°C and 6.5 kbar in conditions of amphibolite and epidote-amphibolite facies occurred 1912-1906 Ma ago. The final stage of the complex evolution - intrusive granite magmatism (veins and small body of enderbites, granites, plagiopegmatites) was 1.89 -1.88 Ma. The further cooling history of the belt was determined by U-Pb dating of titanites and rutiles (1.88-1.87 Ga) and last low-T hydrothermal alterations are fixed by Rb-Sr system of minerals (1.72 Ga). The work is supported by RFBR grant 07-05-00759

Kaulina, Tatiana; Japaskurt, Vasily; Nerovich, Liudmila

2010-05-01

378

The Geological Society of London  

NSDL National Science Digital Library

The Geological Society of London promotes "the geosciences and the professional interests of UK geoscientists." The website offers media, geological, and society news. Researchers can find out about upcoming conferences covering a variety of geological topics as well as information on a series of journals. Everyone interested in geology can find materials on geological careers, including required education, qualifications, and funding. The website provides teaching resources on volcanoes, geologic hazards, and other geological phenomena.

379

9 CFR 95.4 - Restrictions on the importation of processed animal protein, offal, tankage, fat, glands, certain...  

Code of Federal Regulations, 2012 CFR

...importation under that paragraph if the insulin is for the personal medical use of the...ncie . Note to paragraph (f ): Insulin that is not prohibited from importation...Office of Management and Budget under control numbers 0579-0015 and...

2012-01-01

380

9 CFR 95.4 - Restrictions on the importation of processed animal protein, offal, tankage, fat, glands, certain...  

Code of Federal Regulations, 2011 CFR

...importation under that paragraph if the insulin is for the personal medical use of the...ncie . Note to paragraph (f ): Insulin that is not prohibited from importation...Office of Management and Budget under control numbers 0579-0015 and...

2011-01-01

381

Map Showing Geology, Oil and Gas Fields and Geologic Provinces of Africa, Ver. 2.0  

NSDL National Science Digital Library

The US Geological Survey offers the Map Showing Geology, Oil and Gas Fields and Geologic Provinces of Africa Web site and report. The agency's goal for the pieces includes assessing the undiscovered and technically recoverable oil and gas resources of the world. The site includes various descriptions of what the map depicts and how data was processed using Geographic Information Systems. Once the interactive map is activated, users can search and click the map of Africa to view geologic provinces, oil and gas fields, as well as the various surface geological classifications. Although the interface is a bit cumbersome and works best with a fast Internet connection, the unique information provided should draw the attention of those interested in geology. [JAB

Ahlbrandt, Thomas S.; Brownfield, M. E.; Charpentier, Ronald R.; Persits, F. M.; Takahashi, K. I.; Tuttle, M. L.

382

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

383

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

384

D Geological Framework Models as a Teaching Aid for Geoscience  

NASA Astrophysics Data System (ADS)

3D geological models have great potential as a resource for universities when teaching foundation geological concepts as it allows the student to visualise and interrogate UK geology. They are especially useful when dealing with the conversion of 2D field, map and GIS outputs into three dimensional geological units, which is a common problem for all students of geology. Today’s earth science students use a variety of skills and processes during their learning experience including the application of schema’s, spatial thinking, image construction, detecting patterns, memorising figures, mental manipulation and interpretation, making predictions and deducing the orientation of themselves and the rocks. 3D geological models can reinforce spatial thinking strategies and encourage students to think about processes and properties, in turn helping the student to recognise pre-learnt geological principles in the field and to convert what they see at the surface into a picture of what is going on at depth. Learning issues faced by students may also be encountered by experts, policy managers, and stakeholders when dealing with environmental problems. Therefore educational research of student learning in earth science may also improve environmental decision making. 3D geological framework models enhance the learning of Geosciences because they: ? enable a student to observe, manipulate and interpret geology; in particular the models instantly convert two-dimensional geology (maps, boreholes and cross-sections) into three dimensions which is a notoriously difficult geospatial skill to acquire. ? can be orientated to whatever the user finds comfortable and most aids recognition and interpretation. ? can be used either to teach geosciences to complete beginners or add to experienced students body of knowledge (whatever point that may be at). Models could therefore be packaged as a complete educational journey or students and tutor can select certain areas of the model or educational material to incorporate it into an existing area of the syllabus such as a field trip, project work or a certain taxing geological concept such as dip and strike. ? can easily be utilised by students unable to attend university conventionally (illness or disability), distance learning students or for extra curricular activities and continuing professional development courses. ? can be used repeatedly and in such a way as to continually build on geoscience aspects - this practice will improve the student’s geospatial skills. ? can be compared with that seen directly in the field which aids the student in recognising particular patterns or sequences. It also demonstrates how different and complex geology looks in the field and thus how important it is not to rely on models alone. ? are interactive and the accompanying educational material is engaging, dealing with authentic, contemporary scientific problems meaning the student will have to ask questions, think critically and solve problems. ? can often be more practical and better financial alternatives to some teaching methods currently employed. ? incorporate strategies where students first explore, are then introduced to terminology and concepts, finally students apply their knowledge to different, but related problems. This can be further reinforced and explored with fellow students.

Kessler, H.; Ward, E.; Geological Models For Teaching Project Team

2010-12-01

385

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

386

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.

387

California Geological Survey - Landslides  

NSDL National Science Digital Library

This page from the CA Geological Survey (CGS) presents information on landslides as well as maps and products of various past and present CGS programs to map and respond to landslides in the state of California, including the Forest and Watershed Geology Program, the Seismic Hazards Zonation Program, the Caltrans Highway Corridor Mapping project, and the Landslide Map Index.

Survey, California G.

388

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

389

Interpreting Urban Geology.  

ERIC Educational Resources Information Center

Describes field trips to urban locations for geological instruction. The program was developed by the Cleveland Museum of Natural History. Authors claim these field trips have been an effective and enjoyable way of conveying a wide variety of geological information to participants at all levels and backgrounds and have created favorable publicity.…

Hannibal, Joseph Timothy; Schmidt, Mark Thomas

1991-01-01

390

Marine Geological Discoveries  

NSDL National Science Digital Library

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

Hovland, Martin

2010-12-28

391

National Geologic Map Database  

NSDL National Science Digital Library

The National Geologic Map Database (NGMDB) is an Internet-based system for query and retrieval of earth-science map information, created as a collaborative effort between the USGS and the Association of American State Geologists. Its functions include provi