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1

The importance of being cratered: The new role of meteorite impact as a normal geological process  

NASA Astrophysics Data System (ADS)

This paper is a personal (and, in many ways, incomplete) view of the past development of impact geology and of the newly recognized importance of impact events in terrestrial geological history. It also identifies some exciting scientific challenges for future investigators: to determine the full range of impact effects preserved on the Earth, to apply the knowledge obtained from impact phenomena to more general geological problems, and to continue the merger of the once exotic field of impact geology with mainstream geosciences. Since the recognition of an impact event at the Cretaceous-Tertiary (K-T) boundary, much current activity in impact geology has been promoted by traditionally trained geoscientists who have unexpectedly encountered impact effects in the course of their work. Their studies have involved: 1) the recognition of additional major impact effects in the geological record (the Chesapeake Bay crater, the Alamo breccia, and multiple layers of impact spherules in Precambrian rocks); and 2) the use of impact structures as laboratories to study general geological processes (e.g., igneous petrogenesis at Sudbury, Canada and Archean crustal evolution at Vredefort, South Africa). Other research areas, in which impact studies could contribute to major geoscience problems in the future, include: 1) comparative studies between low-level (£7 GPa) shock deformation of quartz, and the production of quartz cleavage, in both impact and tectonic environments; and 2) the nature, origin, and significance of bulk organic carbon ("kerogen") and other carbon species in some impact structures (Gardnos, Norway, and Sudbury, Canada).

French, Bevan M.

2004-02-01

2

Field Geology/Processes  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

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

Oceanography - Marine Geological Processes  

NSDL National Science Digital Library

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

Mcduff, Russell

5

Computer image processing: Geologic applications  

NASA Technical Reports Server (NTRS)

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

Abrams, M. J.

1978-01-01

6

Health benefits of geologic materials and geologic processes  

USGS Publications Warehouse

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

Finkelman, R.B.

2006-01-01

7

Comparison Charts of Geological Processes: Terrestrial Planets  

NSDL National Science Digital Library

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

8

Image Processing Applications for Geologic Mapping  

Microsoft Academic Search

The use of satellite data, particularly Landsat images, for geologic mapping provides the geologist with a powerful tool. The digital format of these data permits applications of image processing to extract or enhance information useful for mapping purposes. Examples are presented of lithologic classification using texture measures, automatic lineament detection and structural analysis, and use of registered multisource satellite data.

Michael Abrams; Annick Blusson; Veronique Carrere; Phu Thien Nguyen; Yves Rabu

1985-01-01

9

Importance of process oriented organizations  

NASA Astrophysics Data System (ADS)

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

Bedic, S.

2013-09-01

10

Image processing applications for geologic mapping  

SciTech Connect

The use of satellite data, particularly Landsat images, for geologic mapping provides the geologist with a powerful tool. The digital format of these data permits applications of image processing to extract or enhance information useful for mapping purposes. Examples are presented of lithologic classification using texture measures, automatic lineament detection and structural analysis, and use of registered multisource satellite data. In each case, the additional mapping information provided relative to the particular treatment is evaluated. The goal is to provide the geologist with a range of processing techniques adapted to specific mapping problems.

Abrams, M.; Blusson, A.; Carrere, V.; Nguyen, T.; Rabu, Y.

1985-03-01

11

Planetary geology: Impact processes on asteroids  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

12

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

13

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

14

Impact as a Geologic Process: Motivations to Drill  

Microsoft Academic Search

Ocean drilling has a vital role to play in the study of impact as a geologic process. All rocky planets undergo impact by asteroids or comets as a process that changes the surface and subsurface of the planet over geologic time. In the case of large impacts these changes can be drastic with effects to the local hydrology, mineral content,

Joanna Morgan; Sean Gulick; Christian Koeberl; Richard Grieve; Gail Christeson

15

Geologic processes on Venus: An update  

NASA Technical Reports Server (NTRS)

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

Masursky, H.

1985-01-01

16

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

17

Abstracts for the Planetary Geology Field Conference on Aeolian Processes  

NASA Technical Reports Server (NTRS)

The Planetary Geology Field Conference on Aeolian Processes was organized at the request of the Planetary Geology Program office of the National Aeronautics and Space Administration to bring together geologists working on aeolian problems on earth and planetologists concerned with similar problems on the planets. Abstracts of papers presented at the conference are arranged herein by alphabetical order of the senior author. Papers fall into three broad categories: (1) Viking Orbiter and Viking Lander results on aeolian processes and/or landforms on Mars, (2) laboratory results on studies of aeolian processes, and (3) photogeology and field studies of aeolian processes on Earth.

Greeley, R. (editor); Black, D. (editor)

1978-01-01

18

The Moon: Keystone to Understanding Planetary Geological Processes and History  

NASA Technical Reports Server (NTRS)

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

2002-01-01

19

Geology  

SciTech Connect

This chapter summarizes the geology of the single-shell tank (SST) farms in the context of the region’s geologic history. This chapter is based on the information in the geology data package for the SST waste management areas and SST RFI Appendix E, which builds upon previous reports on the tank farm geology and Integrated Disposal Facility geology with information available after those reports were published.

Reidel, Stephen P.

2008-01-17

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

Teaching Introductory Geology by a Paradigm, Process and Product Approach  

Microsoft Academic Search

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

M. Reams

2008-01-01

22

Digitizing rocks: Standardizing the process of geologic description with workstations  

SciTech Connect

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

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

1995-06-01

23

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

USGS Publications Warehouse

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

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

1991-01-01

24

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

NSDL National Science Digital Library

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

1900-01-01

25

THE ROLE OF PORE PRESSURE IN DEFORMATION IN GEOLOGIC PROCESSES  

SciTech Connect

A Penrose Conference entitled, "The Role of Pore Pressure in Deformation in Geologic Processes" was convened by the authors at San Diego, California between November 9 and 13, 1979. The conference was sponsored by the Geological Society of America. This report is a summary of the highlights of the issues discussed during the conference. In addition, this report also includes a topical reference list relating to the different subject areas relevant to pore pressure and deformation. The references were compiled from a list suggested by the participants and were available for consultation during the conference. Although the list is far from complete, it should prove to be a good starting point for one who is looking for key papers in the field.

Narasimhan, T. N.; Houston, W. N.; Nur, A. M.

1980-03-01

26

Using Springs to Study Groundwater Flow and Active Geologic Processes  

NASA Astrophysics Data System (ADS)

Spring water provides a unique opportunity to study a range of subsurface processes in regions with few boreholes or wells. However, because springs integrate the signal of geological and hydrological processes over large spatial areas and long periods of time, they are an indirect source of information. This review illustrates a variety of techniques and approaches that are used to interpret measurements of isotopic tracers, water chemistry, discharge, and temperature. As an example, a set of springs in the Oregon Cascades is considered. By using tracers, temperature, and discharge measurements, it is possible to determine the mean-residence time of water, infer the spatial pattern and extent of groundwater flow, estimate basin-scale hydraulic properties, calculate the regional heat flow, and quantify the rate of magmatic intrusion beneath the volcanic arc.

Manga, Michael

27

Geology  

NSDL National Science Digital Library

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

Jennifer Bergman

2009-08-03

28

Salt deposits in the United States and regional geologic characteristics important for storage of radioactive waste  

Microsoft Academic Search

A repository for radioactive waste must isolate radionuclides from the biosphere for long periods of geologic time, during which time the radionuclides would decay to the point where they no longer represent a hazard to man and his ecosystem. Burial of waste in a solidified form in subsurface geologic formations has been considered the most effective and most practical means

K. S. Johnson; S. Gonzales

1978-01-01

29

The importance of precise U-Pb ages in geological correlation  

SciTech Connect

A reduction of lead laboratory background contamination by six orders of magnitude over the past two decades provides a similar reduction in the sample size required for the analysis. Single grains and parts of grains from growth stages in complex populations with a diameter like that of a human hair can now be precisely dated ([+-] 2 m.y., 2 sigma) without a need to average many grains or many spots as with previous conventional or ion microprobe techniques. New methods to eliminate discordance add to the reliability of the method. Precise ages for igneous events, metamorphism, deformation and mineralization provide a means of correlating geological processes at different structural levels and on a scale far greater than normally possible by proximal relationships. Ages of granulite formation and ductile flow in the Superior Province show that these deep level processes occurred more than 50 m.y. after volcanism at the same time as gold deposits formed in active faults at high structural levels. Episodes of isotopic resetting and new zircon growth due to overthrusting in the Grenville Front tectonic zone allow the ages of deformation to be compared for the 1,500 km length of this structure. Dating single zircons in sedimentary packages like the Toridonian sandstone gives the age of a continental source now removed by continental drift. Single zircon cores indicate the protolith age for 372 Ma and 30 Ma granites in Nova Scotia and Chile, respectively. Diabase dykes of the McKenzie dyke swarm separated by up to 2,000 Km can be shown to be coeval at 1,267 [+-] 2 Ma and hence to have formed by a common process of these dimensions. Precise dating of single zircons (microgram size) from the K-T boundary layer that show varying degrees of shock metamorphism define a circa 550 Ma age for the target rock and 65.5 [+-] 3 Ma age for the impact event.

Krogh, T. (Royal Ontario Museum, Toronto, ON (Canada))

1992-01-01

30

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

31

Process for structural geologic analysis of topography and point data  

DOEpatents

A quantitative method of geologic structural analysis of digital terrain data is described for implementation on a computer. Assuming selected valley segments are controlled by the underlying geologic structure, topographic lows in the terrain data, defining valley bottoms, are detected, filtered and accumulated into a series line segments defining contiguous valleys. The line segments are then vectorized to produce vector segments, defining valley segments, which may be indicative of the underlying geologic structure. Coplanar analysis is performed on vector segment pairs to determine which vectors produce planes which represent underlying geologic structure. Point data such as fracture phenomena which can be related to fracture planes in 3-dimensional space can be analyzed to define common plane orientation and locations. The vectors, points, and planes are displayed in various formats for interpretation.

Eliason, Jay R. (Richland, WA); Eliason, Valerie L. C. (Richland, WA)

1987-01-01

32

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

33

Geologic mapping of the Ladakh Himalaya by computer processing of Landsat data  

NASA Technical Reports Server (NTRS)

Computer processed Landsat digital data and field studies have been integrated to make a geologic map of the Indus Suture in the Ladakh Himalaya. This coordinated approach has been successful at locating and identifying the areal extent of the major rock bodies in a 2500 square kilometer area, much of which is inaccessable for conventional field geologic studies.

Francica, J. R.; Birnie, R. W.; Johnson, G. D.

1980-01-01

34

Geological processes and the earth's rotation in the past  

Microsoft Academic Search

The only factor which affects past rates of the earth's rotation and also the moon's rate of recession is the lunar tidal torque. Most geological considerations indicate that this torque would probably be greater and at least comparable to the present, in contrast to the slower rates indicated by the palaeontological and past tidal evidence. It seems that this conflict

D. H. Tarling

1975-01-01

35

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

NASA Astrophysics Data System (ADS)

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

Cheng, Q.

2013-12-01

36

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

SciTech Connect

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

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

1993-11-01

37

Digitizing rocks standardizing the geological description process using workstations  

SciTech Connect

The preservation of geological knowledge in a standardized digital form presents a challenge. Data sources, inherently fuzzy, range in scale from the macroscopic (e.g., outcrop) through the mesoscopic (e.g., hand-specimen) core and sidewall core, to the microscopic (e.g., drill cuttings, thin sections, and microfossils). Each scale change results in increased heterogeneity and potentially contradictory data and the providers of such data may vary in experience level. To address these issues with respect to cores and drill cuttings, a geological description workstation has been developed and is undergoing field trials. Over 1000 carefully defined geological attributes are currently available within a depth-indexed, relational database. Attributes are stored in digital form, allowing multiple users to select familiar usage (e.g., diabase vs. dolerite). Data can be entered in one language and retrieved in other languages. The database structure allow groupings of similar elements (e.g., rhyolites in acidic, igneous or volcanics subgroups or the igneous rock group) permitting different uses to analyze details appropriate to the scale of the usage. Data entry uses a graphical user interface, allowing the geologist to make quick, logical selections in a standardized or custom-built format with extensive menus, on-screen graphics and help screens available. Description ranges are permissible. Entries for lithology, petrology, structures (sedimentary, organic and deformational), reservoir characteristics (porosity and hydrocarbon shows), and macrofossils are available. Sampling points for thin sections, core analysis, geochemistry, or micropaleontology studies are also recorded. Using digital data storage, geological logs using graphical, alphanumeric and symbolic depictions are possible. Data can be integrated with drilling and mud gas data, MWD and wireline data and off well-site analyses to produced composite formation evaluation logs and interpretational crossplots.

Saunders, M.R. (EXLOG (Services), Windsor, Berkshire (United Kingdom)); Shields, J.A. (EXLOG North Sea, Aberdeen (United Kingdom)); Taylor, M.R. (EXLOG, Inc., Houston, TX (United States))

1993-09-01

38

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

39

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

40

The importance of business process modeling in software systems design  

Microsoft Academic Search

Despite diligent efforts made by the software engineering community, the failure of software projects keeps increasing at an alarming rate. After two decades of this problem reoccurring, one of the leading causes for the high failure rate is still poor process modeling (requirements' specification). Therefore both researchers and practitioners recognize the importance of business process modeling in understanding and designing

Joseph Barjis

2008-01-01

41

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

42

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

E-print Network

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

43

Igneous geology of the Carlin trend, Nevada: The importance of Eocene magmatism in gold mineralization  

NASA Astrophysics Data System (ADS)

Igneous rocks of five ages are present in the Carlin trend, Nevada, and include: (1) Paleozoic basalt of the Roberts Mountains allochthon, (2) the Jurassic (˜158 Ma) Goldstrike intrusive complex, which includes the Goldstrike diorite laccolith and abundant dikes and sills, (3) a Cretaceous (112 Ma) granite stock, (4) lavas and intrusions of the Emigrant Pass volcanic field and widespread epizonal plugs and dikes of Eocene (˜40-36 Ma) age that range from rhyolite through basalt, and (5) Miocene (15 Ma) rhyolite lava and tuff. Jurassic and Eocene igneous rocks are by far the most important volumetrically and are spatially associated with nearly all ore deposits of the Carlin trend. This study focuses on the field relations, isotopic dating, and geochemistry of Eocene dikes that intrude sedimentary rocks in many deposits of the Carlin trend, because they are the youngest pre-mineral rocks and have simpler alteration histories than other host rocks. In the Beast, Genesis, Deep Star, Betze-Post, Rodeo-Goldbug, Meikle-Griffin, and Dee-Storm deposits, Eocene dikes are altered, commonly mineralized, and locally constitute ore. Gold-bearing dikes and sedimentary rocks have similar ore mineralogy, including arsenian pyrite, marcasite, and arsenopyrite, with late barite and stibnite. At Beast, as much as half the ore is hosted in a 37.3 Ma rhyolite dike. Post-gold alunite is ˜18.6 Ma. At Meikle and Griffin, porphyritic dacite dikes yield concordant U/Pb zircon and 40Ar/39Ar biotite emplacement ages of ˜39.2 Ma, and illite from the same QSP-altered dacite, with as much 9 ppm Au, yields similar, although imprecise 40Ar/39Ar ages. Thus, gold mineralization at these deposits closely followed emplacement of Eocene dikes. Carlin-type gold deposits in northeastern Nevada have been variously interpreted as partly syngenetic with Paleozoic carbonate rocks, products of Mesozoic contraction and metamorphism with or without significant magmatism, and of Tertiary age and related or not to magmatism, metamorphism, and/or large-scale extension. A recently established Eocene age for major gold introduction narrows the possibilities, and two principal models have emerged: one involving Eocene magmatism as the heat source to drive shallow hydrothermal circulation and the other advocating deeply sourced metamorphic fluids released into the upper crust during regional extension. Critical to the latter argument is the temporal association of extension to gold mineralization, which as yet, is not demonstrated. We argue that Eocene magmatism in the form of large underlying plutons, was the major recognized process that affected the Carlin trend during gold mineralization. These plutons supplied the heat that drove discrete hydrothermal systems. (Abstract shortened by UMI.)

Ressel, Michael Walter, Jr.

44

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

SciTech Connect

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

Mara, S.J.

1980-03-01

45

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

46

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

47

Radiogenic Strontium-87 as an Index of Geologic Processes.  

PubMed

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

Hedge, C E; Walthall, F G

1963-06-14

48

Import, targeting, and processing of a plant polyphenol oxidase  

Microsoft Academic Search

A tomato (Lycopersicon esculentum 1.) gene encoding a precur- sor of polyphenol oxidase (PPO) was transcribed and translated in vitro. lhe import, targeting, and processing of the (35Slmethionine- labeled precursor protein (pPP0) were studied in isolated chloro- plasts. lhe protein was routed to the thylakoid lumen in two steps. lhe 67-kD precursor was first imported into the stroma in an

Amos Sommer; John C. Steffens; Alfred M. Mayer; Eitan Harel

1994-01-01

49

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

50

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.

51

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

NASA Astrophysics Data System (ADS)

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 from the dissipation of energy from the interior of the Earth. Altering the thickness of continental crust via weathering and erosion affects the upper mantle temperature which leads to changes in rates of oceanic crust recycling and consequently rates of outgassing of carbon dioxide into the atmosphere. Estimates for the power generated by various elements in the Earth system are shown. This includes, inter alia, surface life generation of 264 TW of power, much greater than those of geological processes such as mantle convection at 12 TW. This high power results from life's ability to harvest energy directly from the sun. Life need only utilise a small fraction of the generated free chemical energy for geochemical transformations at the surface, such as affecting rates of weathering and erosion of continental rocks, in order to affect interior, geological processes. Consequently when assessing the effects of life on Earth, and potentially any planet with a significant biosphere, dynamical models may be required that better capture the coupled nature of biologically-mediated surface and interior processes.

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

2011-06-01

52

umerical modeling of earthquake processes has become an important  

E-print Network

N umerical modeling of earthquake processes has become an important proving ground for ideas that have no other experimental arena. Nearly all earthquakes originate more than 10 km un- derground some prominent features of earthquake data. Most notably, we study models that emulate the Gutenberg

Preston, Eric

53

Processing of Neutron Diffraction Data for Strain Measurement in Geological Materials  

SciTech Connect

: Conventional rock mechanics testing techniques typically involve the loading of samples and measurement of displacements or strains on the outer boundary of the specimen surface. Neutron diffraction based strain measurement techniques represent a unique and powerful tool for measuring the strain within geological materials under load. The structural variability and non-uniform crystallinity of geological materials, however, create many complexities in the intensity patterns that must be analyzed to quantify strains within the material. The attenuating and scattering properties of the pressure cell housing the sample further add difficulties to the data analysis. This paper describes the methods and processes used to process neutron scattering data for strain measurement in geological materials. It is intended to provide a primer for those in the rock mechanics community that are interested in utilizing this technique along with additional discussion of neutron diffraction experimental factors that may affect data quality.

Polsky, Yarom [ORNL] [ORNL; An, Ke [ORNL] [ORNL; Anovitz, Lawrence {Larry} M [ORNL; Bingham, Philip R [ORNL] [ORNL; Carmichael, Justin R [ORNL] [ORNL; Dessieux Jr, Luc Lucius [ORNL] [ORNL

2014-01-01

54

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

55

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

56

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

Microsoft Academic Search

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

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

2003-01-01

57

Geologic characterization of shelf areas using usSEABED for GIS mapping, modeling processes and assessing marine sand and gravel resources  

USGS Publications Warehouse

Geologic maps depicting offshore sedimentary features serve many scientific and applied purposes. Such maps have been lacking, but recent computer technology and software offer promise in the capture and display of diverse marine data. Continental margins contain landforms which provide a variety of important functions and contain important sedimentary records. Some shelf areas also contain deposits regarded as potential aggregate resources. Because proper management of coastal and offshore areas is increasingly important, knowledge of the framework geology and marine processes is critical. Especially valuable are comprehensive and integrated digital databases based on high-quality information from original sources. Products of interest are GIS maps containing thematic information, such as sediment character and texture. These products are useful to scientists modeling nearshore and shelf processes as well as planners and managers. The U.S. Geological Survey is leading a national program to gather a variety of extant marine geologic data into the usSEABED database system. This provides centralized, integrated marine geologic data collected over the past 50 years. To date, over 340,000 sediment data points from the U.S. reside in usSEABED, which combines an array of physical data and analytical and descriptive information about the sea floor and are available to the marine community through three USGS data reports for the Atlantic, Gulf of Mexico, and Pacific published in 2006, and the project web sites: (http://woodshole.er.usg s.gov/project-pages/aggregates/ and http://walrus.wr.usgs.gov/usseabed/)

Williams, S.J.; Bliss, J.D.; Arsenault, M.A.; Jenkins, C.J.; Goff, J.A.

2007-01-01

58

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

59

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

60

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

61

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

62

Dark Carbon Fixation: An Important Process in Lake Sediments  

PubMed Central

Close to redox boundaries, dark carbon fixation by chemoautotrophic bacteria may be a large contributor to overall carbon fixation. Still, little is known about the relative importance of this process in lake systems, in spite the potentially high chemoautotrophic potential of lake sediments. We compared rates of dark carbon fixation, bacterial production and oxygen consumption in sediments from four Swedish boreal and seven tropical Brazilian lakes. Rates were highly variable and dark carbon fixation amounted up to 80% of the total heterotrophic bacterial production. The results indicate that non-photosynthetic carbon fixation can represent a substantial contribution to bacterial biomass production, especially in sediments with low organic matter content. PMID:23776549

Santoro, Ana Lúcia; Bastviken, David; Gudasz, Cristian; Tranvik, Lars; Enrich-Prast, Alex

2013-01-01

63

Dark carbon fixation: an important process in lake sediments.  

PubMed

Close to redox boundaries, dark carbon fixation by chemoautotrophic bacteria may be a large contributor to overall carbon fixation. Still, little is known about the relative importance of this process in lake systems, in spite the potentially high chemoautotrophic potential of lake sediments. We compared rates of dark carbon fixation, bacterial production and oxygen consumption in sediments from four Swedish boreal and seven tropical Brazilian lakes. Rates were highly variable and dark carbon fixation amounted up to 80% of the total heterotrophic bacterial production. The results indicate that non-photosynthetic carbon fixation can represent a substantial contribution to bacterial biomass production, especially in sediments with low organic matter content. PMID:23776549

Santoro, Ana Lúcia; Bastviken, David; Gudasz, Cristian; Tranvik, Lars; Enrich-Prast, Alex

2013-01-01

64

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

65

Exhibit Development: The Importance of Process and Evaluation  

NASA Astrophysics Data System (ADS)

The Space Science Institute (SSI) is a national leader in developing national traveling exhibitions on space science education (e.g. Electric Space, MarsQuest, Alien Earths, Giant Worlds, Asteroids, and Discover Space). It is also known for developing effective digital media programs (e.g. www.alienearths.org), education workshops for formal and informal educators, and educational films (e.g. Inspire Me: Weightless Flights of Discovery). This paper focuses on the exhibit development process, spanning conceptual planning, design development, fabrication and launch. SSI's exhibit programs also include education and outreach programming and the development of an online version of the exhibit. Examples from Giant Worlds and Asteroids will be used to illustrate these development phases especially the importance of evaluation/research in exhibit development using a logic model approach.

Dusenbery, P.; McLain, B.

2010-08-01

66

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

67

Thermophilic bacilli and their importance in dairy processing.  

PubMed

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

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

2010-12-15

68

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

PubMed

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

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

2009-09-15

69

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

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

70

Geologic Maps Geology 200  

E-print Network

Geologic Maps Geology 200 Geology for Environmental Scientists #12;Geologic Map of the US #12;Symbols found on geologic maps #12;Horizontal Strata #12;Geologic map of part of the Grand Canyon. Each color represents a different formation. #12;Inclined Strata #12;Dome #12;Geologic map of the Black Hills

Kammer, Thomas

71

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

Code of Federal Regulations, 2010 CFR

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

2010-04-01

72

The importance of new processing techniques in tissue engineering  

NASA Technical Reports Server (NTRS)

The use of polymer scaffolds in tissue engineering is reviewed and processing techniques are examined. The discussion of polymer-scaffold processing explains fiber bonding, solvent casting and particulate leaching, membrane lamination, melt molding, polymer/ceramic fiber composite-foam processing, phase separation, and high-pressure processing.

Lu, L.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

1996-01-01

73

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

74

Marine Geology: Research Beneath the Sea  

NSDL National Science Digital Library

Another informative offering from the US Geological Survey is the Marine Geology: Research Beneath the Sea Web site. Visitors can read about the agency's Marine Geology program which "strives to increase our understanding of the geology of the lands covered by water." Topics include methods and equipment used for the research, plate tectonics, resources in the marine realm, predicting effects of marine processes, new frontiers, and even images of marine geology. This interesting and unique site does a good job of explaining and educating the public on this important segment of the agency's research.

75

No geology without marine geology  

Microsoft Academic Search

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

P. H Kuenen

2002-01-01

76

The importance of core-drilling as a research instrument: The Oklahoma Geological Survey's scientific drilling program  

SciTech Connect

The Oklahoma Geological Survey's drilling rig represents a unique scientific facility within the State with the capability to investigate geologic targets to a depth of 1,000 feet. The drilling rig serves as an ideal research tool for hypothesis testing, sample acquisition, and establishment of stratigraphic control points in regions of poorly exposed outcrops and in regions where access to outcrops is limited. Core-hole data help: (1) to establish and correct sequence correlations from shelf to basin, (2) correct surface and subsurface mapping errors, (3) verify geologic structures, (4) propose depositional models, (5) gather data concerning the distribution, thickness, characteristics, and areal extent of coal deposits and associated strata, (6) designate reference wells near previously established surface type sections (localities) for outcrop to subsurface correlations, (7) document the geometry, thickness, and lateral extent of major and secondary laterally discontinuous Pennsylvanian-Permian sandstone producing reservoirs, (8) identify physical surfaces (e.g., sequence boundaries, transgressive/regressive surfaces, maximum flooding surfaces, etc.) and stratal stacking patterns, and (9) provide cores for public use from stratigraphic intervals that are poorly known. Some results from newly acquired core-hole data include (1) recognition of several previously unidentified coal beds in the shelf area and their correlation with coals in the basin, (2) documentation of the stratigraphic position and lateral continuity of locally reported sandstone-producing reservoirs, and (3) confirmation that many lithostratigraphic units of previously uncertain stratigraphic position and continuity in the subsurface can be stratigraphically correlated to surface sections.

Chaplin, J.R. (Oklahoma Geological Survey, Norman, OK (United States). Energy Center)

1993-02-01

77

Laser ablation ICP-MS applications using the timescales of geologic and biologic processes  

NASA Astrophysics Data System (ADS)

Geochemists commonly examine geologic processes on timescales of 10^4--10^9 years, and accept that often age relations, e.g., chemical zoning in minerals, can only be measured in a relative sense. The progression of a geologic process that involves geochemical changes may be assessed using trace element microbeam techniques, because the textural, and therefore spatial context, of the analytical scheme can be preserved. However, quantification requires appropriate calibration standards. Laser ablation ICP-MS (LA-ICP-MS) is proving particularly useful now that appropriate standards are becoming available. For instance, trace element zoning patterns in primary sulfides (e.g., pyrite, sphalerite, chalcopyrite, galena) and secondary phases can be inverted to examine relative changes in fluid composition during cycles of hydrothermal mineralization. In turn such information provides insights into fluid sources, migration pathways and depositional processes. These studies have only become possible with the development of appropriate sulfide calibration standards. Another example, made possible with the development of appropriate silicate calibration standards, is the quantitative spatial mapping of REE variations in amphibolite-grade garnets. The recognition that the trace and major elements are decoupled provides a better understanding of the various sources of elements during metamorphic re-equilibration. There is also a growing realization that LA-ICP-MS has potential in biochemical studies, and geochemists have begun to turn their attention in this direction, working closely with biologists. Unlike many geologic processes, the timescales of biologic processes are measured in years to centuries and are frequently amenable to absolute dating. Examples that can be cited where LA-ICP-MS has been applied include annual trace metal variations in tree rings, corals, teeth, bones, bird feathers and various animal vibrissae (sea lion, walrus, wolf). The aim of such studies is to correlate trace element variations with changes in environmental variables. Such studies are proving informative in climate change and habitat management. Again, such variations have been quantified with the availability of appropriate organic, carbonate and phosphate calibration standards.

Ridley, W. I.

2003-04-01

78

Molecular connections between nuclear and ciliary import processes  

PubMed Central

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

2013-01-01

79

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.

80

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

81

Geologic nozzles  

USGS Publications Warehouse

The importance of the low characteristic velocities of geologic fluids has not been widely recognized, and as a result, the importance of supercritical and supersonic flow in geological processes has generally been underestimated. The lateral blast at Mount St. Helens, Washington, propelled a gas heavily laden with dust into the atmosphere. Because of the low sound speed in this gas (about 100 m/s), the flow was internally supersonic. Old Faithful Geyser, Wyoming, is a converging-diverging nozzle in which liquid water refilling the conduit during the recharge cycle changes during eruption into a two-phase liquid-vapor mixture with a very low sound velocity. The high sound speed of liquid water determines the characteristics of harmonic tremor observed at the geyser during the recharge interval, whereas the low sound speed of the liquid-vapor mixture influences the fluid flow characteristics of the eruption. At the rapids of the Colorado River in the Grand Canyon, Arizona, the channel is constricted into the shape of a converging-diverging nozzle by the debris flows that enter from tributary canyons. Both subcritical and supercritical flow occur within the rapids. -from Author

Werner, Kieffer S.

1989-01-01

82

Identifying Cognitive Processes Important to Mathematics Learning but Often Overlooked  

ERIC Educational Resources Information Center

In August 2010, ACER held its annual conference in Melbourne. The theme of the 2010 conference--"Teaching Mathematics? Make It Count"--was chosen to highlight that mathematics education is an area of high priority in Australia. In the author's own presentation to the conference, he outlined research into an area that he believes is very important…

Turner, Ross

2011-01-01

83

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.

84

Team Teachers: The Importance of the Selection Process.  

ERIC Educational Resources Information Center

Discusses the team teaching process developed in the Washoe County School District in Reno, Nevada, resulting from the Nevada Legislature's mandate to reduce class size to a 15:1 ratio. Describes the nature of team relationships and how teachers came to teach in a team situation. Advises teacher input in team partner selection as essential to…

Matranga, Myrna

1992-01-01

85

Quantifying the rainfall-water level fluctuation process in a geologically complex lake catchment.  

PubMed

Simulating hydrologic processes in geologically complex environments is a difficult scientific task since it incorporates high level of uncertainty. Many studies have attempted to accurately quantify the rainfall-water level elevation relationship in freshwater bodies so as to predict flooding and drought events. For this purpose several types of models have been implemented including distributed, black box and conceptual models that often provide efficient results, depending on the availability of reliable data as well as on the level of understanding of the system. Nevertheless, in the particular effort, three different models have been used to describe the relationship between rainfall and water level elevation in Trichonis Lake during the period 1951-1997. A Transfer Function model, a Dynamic Linear Regression and a physically based model, consisting of the lake's water budget equation, its Digital Bathymetric Model and GIS algorithms. These models have been tested to assess their efficiency and applicability in a karstic environment and the aim of the study was to find the best modeling option for developing sustainable water management plans and establishing a flooding/drought warning system in the particular lake catchment. The results indicated that in areas with geologically complex conditions, simple, physically-based models operate better than mechanistic models which usually cannot describe adequately the complexity of the system. PMID:16741814

Elias, Dimitriou; Ierotheos, Zacharias

2006-08-01

86

Development of multiple source data processing for structural analysis at a regional scale. [digital remote sensing in geology  

NASA Technical Reports Server (NTRS)

Various image processing techniques developed for enhancement and extraction of linear features, of interest to the structural geologist, from digital remote sensing, geologic, and gravity data, are presented. These techniques include: (1) automatic detection of linear features and construction of rose diagrams from Landsat MSS data; (2) enhancement of principal structural directions using selective filters on Landsat MSS, Spacelab panchromatic, and HCMM NIR data; (3) directional filtering of Spacelab panchromatic data using Fast Fourier Transform; (4) detection of linear/elongated zones of high thermal gradient from thermal infrared data; and (5) extraction of strong gravimetric gradients from digitized Bouguer anomaly maps. Processing results can be compared to each other through the use of a geocoded database to evaluate the structural importance of each lineament according to its depth: superficial structures in the sedimentary cover, or deeper ones affecting the basement. These image processing techniques were successfully applied to achieve a better understanding of the transition between Provence and the Pyrenees structural blocks, in southeastern France, for an improved structural interpretation of the Mediterranean region.

Carrere, Veronique

1990-01-01

87

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

88

A Temperature-Profile Method for Estimating Flow Processes in Geologic Heat Pipes  

SciTech Connect

Above-boiling temperature conditions, as encountered, for example, in geothermal reservoirs and in geologic repositories for the storage of heat-producing nuclear wastes, may give rise to strongly altered liquid and gas flow processes in porous subsurface environments. The magnitude of such flow perturbation is extremely hard to measure in the field. We therefore propose a simple temperature-profile method that uses high-resolution temperature data for deriving such information. The energy that is transmitted with the vapor and water flow creates a nearly isothermal zone maintained at about the boiling temperature, referred to as a heat pipe. Characteristic features of measured temperature profiles, such as the differences in the gradients inside and outside of the heat pipe regions, are used to derive the approximate magnitude of the liquid and gas fluxes in the subsurface, for both steady-state and transient conditions.

J.T. Birkholzer

2005-01-21

89

The importance of cost considerations in the systems engineering process  

NASA Technical Reports Server (NTRS)

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

Hodge, John D.

1993-01-01

90

Millikan Lecture 1994: Understanding and teaching important scientific thought processes  

NSDL National Science Digital Library

Physics is an intellectually demanding discipline and many students have difficulties learning to deal with it. Further, our instruction is often far less effective than we realize. Indeed, recent investigations have revealed that many students, even when getting good grades, emerge from their basic physics courses with signification scientific misconcepts, with prescientific notions, with poor problem-solving skills, and with an inability to apply what they ostensibly learned. In short, students' acquired physics knowledge is often largely nominal rather than functiional. This situation leads one to ask: Why is this so, and what can be done about it? More specifically, it has led me to address the following two basic questions: (a) Can one understand better the underlying throught processes required to deal with a science like physics? (b) How can such an understanding be used to design more effective instruction? These are the questions which have been the focus of my work during the last several years and which I want to discuss in this article.

Reif, Frederick

2011-07-28

91

Processes of lunar crater degradation - Changes in style with geologic time  

NASA Technical Reports Server (NTRS)

Relative age schemes of crater degradation are calibrated to radiometric dates obtained from lunar samples, changes in morphologic features are analyzed, and the style and rate of lunar surface degradation processes are modeled in relation to lunar geologic time. A comparison of radiometric age scales and the relative degradation of morphologic features for craters larger than about 5 km in diameter shows that crater degradation can be divided into two periods: Period I, prior to about 3.9 billion years ago and characterized by a high meteoritic influx rate and the formation of large multiringed basins, and Period II, from about 3.9 billion years ago to the present and characterized by a much lower influx rate and a lack of large multiringed basins. Diagnostic features for determining the relative ages of craters are described, and crater modification processes are considered, including primary impacts, lateral sedimentation, proximity weathering, landslides, and tectonism. It is suggested that the fundamental degradation of early Martian craters may be associated with erosional and depositional processes related to the intense bombardment characteristics of Period I.

Head, J. W.

1975-01-01

92

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

93

Geology, summary  

NASA Technical Reports Server (NTRS)

Trends in geologic application of remote sensing are identified. These trends are as follows: (1) increased applications of orbital imagery in fields such as engineering and environmental geology - some specific applications include recognition of active earthquake faults, site location for nuclear powerplants, and recognition of landslide hazards; (2) utilization of remote sensing by industry, especially oil and gas companies, and (3) application of digital image processing to mineral exploration.

Sabins, F. F., Jr.

1975-01-01

94

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

95

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

Microsoft Academic Search

The second meeting of the Consultants on Coupled Processes Associated with Geological Disposal of Nuclear Waste occurred on January 15-16, 1985 at Lawrence Berkeley Laboratory (LBL). All the consultants were present except Dr. K. Kovari, who presented comments in writing afterward. This report contains a brief summary of the presentations and discussions from the meeting. The main points of the

Chin-Fu Tsang; D. C. Mangold

1985-01-01

96

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

97

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

98

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. 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. In addition, we present results of 3D dynamical models of subduction in which these materials were used to lubricate the plate's interface and test different degrees of mechanical coupling.

Duarte, Joao; Schellart, Wouter; Cruden, Alexander

2014-05-01

99

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

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

100

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

101

September 2012 BASIN RESEARCH AND ENERGY GEOLOGY  

E-print Network

September 2012 BASIN RESEARCH AND ENERGY GEOLOGY STATE UNIVERSITY OF NEW YORK at BINGHAMTON research programs in geochemistry, sedimentary geology, or Earth surface processes with the potential the position, visit the Geological Sciences and Environmental Studies website (www.geology

Suzuki, Masatsugu

102

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.

103

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

NASA Astrophysics Data System (ADS)

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

Ortega, L.; Oyarúun, R.; Gallego, M.

1996-03-01

104

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

NASA Astrophysics Data System (ADS)

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

McCurdy, K. M.

2007-12-01

105

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

NASA Astrophysics Data System (ADS)

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

Nitkina, Elena

2013-04-01

106

Explorational Rock Physics – The Link Between Geological Processes and Geophysical Observables  

Microsoft Academic Search

\\u000a The field of rock physics represents the link between qualitative geological parameters and quantitative geophysical measurements.\\u000a Increasingly over the last decade, rock physics has become an integral part of quantitative seismic interpretation and stands\\u000a out as a key technology in petroleum geophysics. Ultimately, the application of rock physics tools can reduce exploration\\u000a risk and improve reservoir forecasting in the petroleum

Per Avseth

107

Groundwater as a geologic agent: An overview of the causes, processes, and manifestations  

Microsoft Academic Search

The objective of the present paper is to show that groundwater is a general geologic agent. This perception could not, and\\u000a did not, evolve until the system nature of basinal groundwater flow and its properties, geometries, and controlling factors\\u000a became recognized and understood through the 1960s and 1970s.\\u000a \\u000a The two fundamental causes for groundwater's active role in nature are its

József Tóth

1999-01-01

108

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

Federal Register 2010, 2011, 2012, 2013

...Establishment of a Commodity Import Approval Process Web Site AGENCY: Animal and Plant Health Inspection...of a new Plant Protection and Quarantine Web site that will provide stakeholders with...comment on draft risk assessments. This Web site will make the commodity import...

2012-06-26

109

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

110

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

E-print Network

ORIGINAL ARTICLE doi:10.1111/j.1558-5646.2009.00743.x DO GEOLOGICAL OR CLIMATIC PROCESSES DRIVE SPECIATION IN DYNAMIC ARCHIPELAGOS? THE TEMPO AND MODE OF DIVERSIFICATION IN SOUTHEAST ASIAN SHREWS Jacob A. Esselstyn, 1,2 Robert M. Timm, 1,3 and Rafe... M. Brown 1,4 1 Biodiversity Research Center and Department of Ecology & Evolutionary Biology, University of Kansas, 1345 Jayhawk Boulevard, Lawrence, Kansas 66045 2 E-mail: esselsty@ku.edu 3 E-mail: btimm@ku.edu 4 E-mail: rafe@ku.edu Received August...

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

2009-10-01

111

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

USGS Publications Warehouse

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

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

2008-01-01

112

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

113

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

114

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

115

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

Code of Federal Regulations, 2013 CFR

...on the importation of processed animal protein, offal, tankage, fat, glands, certain...on the importation of processed animal protein, offal, tankage, fat, glands, certain...this chapter: (i) Processed animal protein, tankage, offal, and tallow...

2013-01-01

116

7 CFR 319.56-11 - Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Importation of dried, cured, or processed fruits, vegetables...319.56-11 Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes. (a) Dried, cured, or processed fruits and...

2011-01-01

117

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

118

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.

119

Geological Survey research 1978  

USGS Publications Warehouse

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

U.S. Geological Survey

1978-01-01

120

Geological Survey research 1976  

USGS Publications Warehouse

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

U.S. Geological Survey

1976-01-01

121

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

122

Flow Tube Studies of Gas Phase Chemical Processes of Atmospheric Importance  

NASA Technical Reports Server (NTRS)

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

Molina, Mario J.

1997-01-01

123

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

Microsoft Academic Search

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

Oliver Bown

124

Mutation is arguably the most important of all genetic processes, generating genetic variation between indi-  

E-print Network

Mutation is arguably the most important of all genetic processes, generating genetic variation between indi- viduals within a species and between cells within an individual. In doing so, mutation the very first investigations into the pat- tern of mutation -- conducted on the rII region

Eyre-Walker, Adam

125

Abstract --Image segmentation plays an important role in medical image processing. The aim of conventional hard  

E-print Network

Abstract -- Image segmentation plays an important role in medical image processing. The aim within each voxel, which we call a mixture, was considered in establishing an image segmentation-EM mixture segmentation methodology was tested by digital phantom MR and patient CT images with PV effect

126

Self-Assessment Processes: The Importance of Follow-up for Success  

ERIC Educational Resources Information Center

Purpose: The purpose of this paper is to review the literature on self-assessment processes and to identify the difficulties, benefits and success factors of the European Foundation for Quality Management self-assessment model, analysing the importance of follow-up. Design/methodology/approach: First, the paper carries out a literature review on…

Tari, Juan Jose

2010-01-01

127

Signaling by Sonic hedgehog (Shh) controls important developmental processes, including dorsoventral neural tube  

E-print Network

57 Signaling by Sonic hedgehog (Shh) controls important developmental processes, including Decapentaplegic Hh Hedgehog NPC1 Niemann-Pick C1 opb open brain Ptc Patched Shh Sonic hedgehog ski skinny hedgehog Sonic hedgehog (Shh), a member of the Hedgehog (Hh) family of secreted signaling proteins, carries out

Quake, Stephen R.

128

Vesta: A Geological Overview  

NASA Astrophysics Data System (ADS)

Observations from the Dawn spacecraft [1] enable the derivation of the asteroid 4Vesta's shape, facilitate mapping of the surface geology, and provide the first evidence for interpreting Vesta's geological evolution. Science data were acquired during the approach to Vesta, a circular polar (Survey) orbit at an altitude of 2700 km providing ~ 230 m/pix camera scale, and during a circular high-altitude mapping orbit (HAMO) at 700 km altitude with a camera scale of ~ 65 m/pixel. Currently Dawn is orbiting Vesta in a low-altitude mapping orbit (LAMO) at 210 km altitude, yielding a global image coverage of ~20 m/pixel at the time of EGU [2,3,4,5]. Geomorphology and distribution of surface features provide evidence for impact cratering, tectonic activity, and regolith and probable volcanic processes. Craters with dark rays, bright rays, and dark rim streaks have been observed, suggesting buried stratigraphy. The largest fresh craters retain a simple bowl-shaped morphology, with depth/diameter ratios roughly comparable to lunar values. The largest crater Rheasilvia, an ~500 km diameter depression at the south pole, includes an incomplete inward facing cuspate scarp and a large central mound surrounded by unusual complex arcuate ridge and groove patterns, and overlies an older ~400 km wide basin. A set of large equatorial troughs is related to these south polar structures. Vesta exhibits rugged topography ranging from -22 km to +19 km relative to a best fit ellipsoidal shape. Vesta's topography has a much greater range in elevation relative to its radius (15%) than do the Moon and Mars (1%) or the Earth (0.3%), but less than highly battered smaller asteroids like Lutetia (40%). This also identifies Vesta as a transitional body between asteroids and planets. The surface of Vesta exhibits very steep topographic slopes that are near the angle of repose. Impacts onto these steep surfaces, followed by slope failure, make resurfacing - due to impacts and their associated gravitational forces and seismic activity - an important geologic process on Vesta that significantly alters the morphology of geologic features and adds to the complexity of its geologic history. In general, Vesta's geology is more like the Moon and rocky planets than other asteroids.

Jaumann, R.

2012-04-01

129

7 CFR 319.56-11 - Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes.  

Code of Federal Regulations, 2012 CFR

...Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes. ...AGRICULTURE FOREIGN QUARANTINE NOTICES Fruits and Vegetables § 319.56-11 Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes....

2012-01-01

130

7 CFR 319.56-11 - Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes.  

Code of Federal Regulations, 2013 CFR

...Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes. ...AGRICULTURE FOREIGN QUARANTINE NOTICES Fruits and Vegetables § 319.56-11 Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes....

2013-01-01

131

7 CFR 319.56-11 - Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes.  

...Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes. ...AGRICULTURE FOREIGN QUARANTINE NOTICES Fruits and Vegetables § 319.56-11 Importation of dried, cured, or processed fruits, vegetables, nuts, and legumes....

2014-01-01

132

Geological structures  

Microsoft Academic Search

Here is an account of recent thinking in structural geology and tectonics. The book begins with a discussion of the history of geological structures, their division, and research techniques. It then introduces a broad range of viewpoints. Using examples, the book examines geological structures in the context of their geographical location. It considers the tectonic mechanisms which produce geologic structures.

T. Uemura; S. Mizutani

1984-01-01

133

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

134

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)

Due to the strong evidence for aqueous processes at or near the surface, Mars is the most Earth-like body in the Solar System. After 10 years of ESA's Mars Express orbiting the planet its High Resolution Stereo Camera (HRSC) covered about 90 % of the surface in stereo and color with resolutions up to 10 m/pixel [1]. Digital elevation models of up to 50 m grid spacing, generated from all suitable datasets of the stereo coverage, currently cover about 40 % of the surface [2]. The geomorphological analysis of surface features, observed by the HRSC indicate major surface modifications by endogenic and exogenic processes on 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], suggesting that no unique processes are required to explain their formation. 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 is prominent glaciation and periglacial features at several latitudes, including mountain glaciers [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 significantly dynamic surface environment, characterized by widespread erosion, transport, and redeposition [26]. Since basically all geologic interpretations of extraterrestrial features require profound knowledge of the Earth as key reference, studies of terrestrial analogues are mandatory in planetary geology. Field work in Antarctica, Svalbard and Iceland [5,6,21,22,27] provided a basis for the analysis of periglacial and volcanic processes, respectively. 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; [27]Hauber et al., 2011, Geol. Soc. Am. 483.

Jaumann, R.; Neukum, G.; Hauber, E.; Hoffmann, H.; Roatsch, T.; Gwinner, K.; Scholten, F.; Di Achille, G.; Duxbury, T.; Erkeling, G.; van Gasselt, S.; Gupta, S.; Head, J. W.; Hiesinger, H.; Ip, W.; Keller, H.; Kleinhans, M. G.; Kneissl, T.; Le Deit, L.; McCord, T. B.; Muller, J.; Murray, J. J.; Pacifici, A.; Platz, T.; Pinet, P. C.; Reiss, D.; Rossi, A.; Spohn, T.; Tirsch, D.; Williams, D. A.

2013-12-01

135

Important role of autophagy in regulation of metabolic processes in health, disease and aging.  

PubMed

Autophagy is the basic catabolic mechanism that involves degradation of dysfunctional cellular components through the action of lysosome as well as supplying energy and compounds for the synthesis of essential biomacromolecules. This process enables cells to survive stress from the external environment like nutrient deprivation. Autophagy is important in the breakdown of proteins, carbohydrates and lipids as well. Furthermore, recent studies have shown that autophagy is critical in wide range of normal human physiological processes, and defective autophagy is associated with diverse diseases, including lysosomal storage disease, myopathies, neurodegeneration and various metabolic disorders. This review summarizes the most up-to-date findings on what role autophagy plays in metabolism. PMID:24702497

Papá?ková, Z; Cahová, M

2014-09-01

136

Petroleum geology of Tunisia  

Microsoft Academic Search

Recent discoveries and important oil shows have proven the existence of hydrocarbons in newly identified depocenters and reservoirs. In general, except for some areas around the producing fields, Tunisia is largely underdrilled. The national company ETAP has decided to release data and to publish a synthesis on the petroleum geology of Tunisia. The geology of Tunisia provides a fine example

P. F. Burollet; A. B. Ferjami; F. Mejri

1990-01-01

137

Geology Before Pluto: Pre-encounter Considerations  

NASA Technical Reports Server (NTRS)

Pluto, its large satellite Charon, and its four 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 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, the 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 observations. 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 New Horizons' cameras that will bear most directly on geological interpretability. Then I will broadly review major geological processes that could potentially operate of 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 prospects for endogenic activity in the form of tectonics and cryo-volcanism.

Moore, Jeffrey M.

2014-01-01

138

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

NASA Astrophysics Data System (ADS)

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

Sharkov, E.; Bogatikov, O.

2009-04-01

139

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

140

Geological Survey research 1981  

USGS Publications Warehouse

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

U.S. Geological Survey

1982-01-01

141

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

142

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

143

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

144

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

145

Geological Sciences Jeffrey D. Keith, Chair  

E-print Network

it from the time of formation of the solar system. With the development of remote sensing technology and the exploration of the solar system by spacecraft, geological sciences have become increasingly important the sun. Understanding the dynamic processes of Earth and other planets is relevant to many societal needs

Hart, Gus

146

Geologic Map of North America  

USGS Multimedia Gallery

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

147

Phylogenetic Gaussian Process Model for the Inference of Functionally Important Regions in Protein Tertiary Structures  

PubMed Central

A critical question in biology is the identification of functionally important amino acid sites in proteins. Because functionally important sites are under stronger purifying selection, site-specific substitution rates tend to be lower than usual at these sites. A large number of phylogenetic models have been developed to estimate site-specific substitution rates in proteins and the extraordinarily low substitution rates have been used as evidence of function. Most of the existing tools, e.g. Rate4Site, assume that site-specific substitution rates are independent across sites. However, site-specific substitution rates may be strongly correlated in the protein tertiary structure, since functionally important sites tend to be clustered together to form functional patches. We have developed a new model, GP4Rate, which incorporates the Gaussian process model with the standard phylogenetic model to identify slowly evolved regions in protein tertiary structures. GP4Rate uses the Gaussian process to define a nonparametric prior distribution of site-specific substitution rates, which naturally captures the spatial correlation of substitution rates. Simulations suggest that GP4Rate can potentially estimate site-specific substitution rates with a much higher accuracy than Rate4Site and tends to report slowly evolved regions rather than individual sites. In addition, GP4Rate can estimate the strength of the spatial correlation of substitution rates from the data. By applying GP4Rate to a set of mammalian B7-1 genes, we found a highly conserved region which coincides with experimental evidence. GP4Rate may be a useful tool for the in silico prediction of functionally important regions in the proteins with known structures. PMID:24453956

Huang, Yi-Fei; Golding, G. Brian

2014-01-01

148

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

149

Is photon angular momentum important in molecular collision processes occurring in a laser field  

NASA Technical Reports Server (NTRS)

The importance of the rigorous treatment of photon angular momentum in molecular-collision processes occurring in the presence of intense radiation is investigated. An alternate approximate treatment, which essentially neglects the angular momentum coupling between the photon and the molecular degrees of freedom by averaging over the angular dependence of the interaction matrix elements, is presented and applied to a model calculation. The degeneracy-averaged results of this calculation compare remarkably well with the results of a rigorous calculation, from which we conclude (with reservation) that the explicit consideration of photoangular momentum coupling in molecular-collision problems is unnecessary.

Devries, P. L.; George, T. F.

1978-01-01

150

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

151

Geologic processes on the Galilean satellite Callisto: Galileo SSI results, open questions, and requirements for camera data in a future mission to Jupiter  

NASA Astrophysics Data System (ADS)

The second-largest satellite of Jupiter, Callisto, is characterized by a unique surface geology dominated by impact and erosional processes [1][2]. Tectonic features occur but are much less pervasive than on Callisto's inner neighbour Ganymede [1][2][3]. It remains still an unsolved question if cryovolcanism was ever active in Callisto's early history [2][3][4][5]. One common feature of the two largest Galilean satellites Callisto and Ganymede is the strong similarity in impact crater forms which implies a similar sub-surface structure [1][6][7]. Since Callisto's surface was the least imaged one by the Galileo SSI camera, the record of geologic units and landforms of this enigmatic satellite remains incomplete. In this paper, we (1) present characteristics of landforms and geologic units, (2) relative and absolute ages of these units, (3) discuss open issues, and (4) suggest requirements for camera data in a future mission to Jupiter and to its satellites.

Wagner, R. J.; Neukum, G.

2008-09-01

152

Assessment Report, Department of Geology August, 2012  

E-print Network

Assessment Report, Department of Geology August, 2012 1. Learning Goals ALL students in geology, classification schemes, geologic history and processes, and the structure of the Earth. 3. demonstrate an understanding of the variability, complexity, and interdependency of processes within geologic systems. 4. use

Bogaerts, Steven

153

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

154

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

PubMed Central

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

2011-01-01

155

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

156

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

157

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

NASA Astrophysics Data System (ADS)

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

Cardarelli, E.; Francis, C. A.

2013-12-01

158

Influence of fluvial processes on the quaternary geologic framework of the continental shelf, North Carolina, USA  

USGS Publications Warehouse

Digital, single-channel, high-resolution seismic reflection profiles were acquired from the insular continental shelf of North Carolina, USA along a data grid extending from Oregon Inlet northward 48 km to Duck, North Carolina and from the nearshore zone seaward approximately 28 km (total surveyed area= 1334 km2). These data were processed and interpreted to delineate principal reflecting horizons and develop a three-dimensional seismic stratigraphic framework for the continental shelf that was compared to stratigraphic data from the shoreward back-barrier (estuarine) and barrier island system. Six principal reflecting horizons (designated R0 through R5) were present within the upper 60 m of the shelf stratigraphic succession. Three-dimensional mapping of reflector R1 demonstrated its origin from fluvial incision of the continental shelf during an episode (or episodes) of lowered sea-level. Fluvial processes during development of reflector R1 were responsible for extensive reworking and re-deposition of sediment throughout most of the northern half of the study area. Five seismic stratigraphic units (designated S1 through S5) were tentatively correlated with depositional sequences previously identified from the North Carolina back-barrier (estuarine) and barrier island system. These five stratigraphic units span the Quaternary Period (S1 = early Holocene; S2 = 51-78 ka; S3 = 330-530 ka; S4 = 1.1-1.8 Ma; S5 = earliest Pleistocene). Unit S1 is composed of fine-grained fluvial/estuarine sediment that back-filled incised streams during early Holocene sea-level rise. The four other stratigraphic units (S2-S5) display tabular depositional geometries, low total relief, and thicken toward the east-southeast as their basal reflectors dip gently between 0.41 m km-1 (0.02??) and 0.54 m km-1 (0.03??). Knowledge of the three-dimensional subsurface stratigraphic architecture of the continental shelf enhances understanding of the development of shelf depositional successions and provides a framework for development of better Quaternary sea-level data, especially offshore North Carolina where such data are sparse. ?? 2002 Elsevier Science B.V. All rights reserved.

Boss, S.K.; Hoffman, C.W.; Cooper, B.

2002-01-01

159

Geologic mapping of Vesta  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

160

A Domain Decomposition Approach for Large-Scale Simulations of Flow Processes in Hydrate-Bearing Geologic Media  

SciTech Connect

Simulation of the system behavior of hydrate-bearing geologic media involves solving fully coupled mass- and heat-balance equations. In this study, we develop a domain decomposition approach for large-scale gas hydrate simulations with coarse-granularity parallel computation. This approach partitions a simulation domain into small subdomains. The full model domain, consisting of discrete subdomains, is still simulated simultaneously by using multiple processes/processors. Each processor is dedicated to following tasks of the partitioned subdomain: updating thermophysical properties, assembling mass- and energy-balance equations, solving linear equation systems, and performing various other local computations. The linearized equation systems are solved in parallel with a parallel linear solver, using an efficient interprocess communication scheme. This new domain decomposition approach has been implemented into the TOUGH+HYDRATE code and has demonstrated excellent speedup and good scalability. In this paper, we will demonstrate applications for the new approach in simulating field-scale models for gas production from gas-hydrate deposits.

Zhang, Keni; Moridis, G.J.; Wu, Y.-S.; Pruess, K.

2008-07-01

161

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

162

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

163

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

164

The importance of manufacturing processes and their control for the reliability of CPV systems  

NASA Astrophysics Data System (ADS)

Highly concentrating photovoltaic systems (HCPV) based on III-V multi-junction solar cells entered the PV market recently. Since 2008, HCPV power plants operate in various countries and valuable experiences could be gained. Reliability and durability of CPV power plant components are very much impacting the overall life cycle costs of a CPV power plant. Especially the CPV module is a critical component when considering system life time and overall economics. Soitec's CPV Modules based on Concentrix{trade mark, serif} technology are designed for outstanding robustness and reliability even under harsh environmental conditions. The reliability of a CPV module depends significantly on the manufacturing processes and their control. Therefore it is important to design CPV modules for manufacturability.

Gombert, Andreas; Rubio, Francisca

2013-09-01

165

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

NASA Technical Reports Server (NTRS)

The objective of this study is 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 such as HCl with ice surfaces in order to elucidate the mechanism of heterogeneous chlorine activation processes, using both a theoretical and an experimental approach. The measurements will be carried out under temperature and pressure conditions covering those applicable to the stratosphere and upper troposphere. The techniques to be employed include turbulent flow - chemical ionization mass spectrometry, and optical ellipsometry. The next section summarizes our research activities during the second year of the project, and the section that follows consists of the statement of work for the third year.

Molina, Mario J.

2001-01-01

166

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

167

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

168

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

169

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 ice cap, Svalbard, is one of the fastest outlet glaciers in Svalbard, and shows dramatic changes since 1995. In addition to previously observed seasonal summer speed-up associated with the melt season, the winter speed of B3 has accelerated approximately fivefold since 1995. We use the Elmer/Ice full-Stokes model for ice dynamics to infer spatial distributions of basal drag for the winter seasons of 1995, 2008 and 2011. This "inverse" method is based on minimising discrepancy between modelled and observed surface velocities, using satellite remotely sensed velocity fields. We generate steady-state temperature distributions for 1995 and 2011. Frictional heating caused by basal sliding contributes significantly to basal temperatures of the B3 outlet glacier, with heat advection (a longer-timescale process than frictional heating) also being important in the steady state. 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 2 m year-1. Hence it is essential to incorporate the evolution of basal processes in future projections of the evolution of B3. Informed by a combination of our inverse method results and previous studies, we hypothesise a system of processes and feedbacks involving till deformation and basal hydrology to explain both the seasonal accelerations (short residence time pooling of meltwater at the ice-till interface) and the ongoing interannual speed-up (gradual penetration of water into the till, reducing till strength).

Gladstone, R.; Schäfer, M.; Zwinger, T.; Gong, Y.; Strozzi, T.; Mottram, R.; Boberg, F.; Moore, J. C.

2014-08-01

170

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

171

Biological nitrogen fixation is a much more important process in the nitrogen cycle of the oceans than previously thought.  

E-print Network

341 Biological nitrogen fixation is a much more important process in the nitrogen cycle Introduction A revolution in our understanding of the marine nitrogen cycle and the role of microorganisms revise our view of the quantitative importance of this process in the nitrogen cycle of the present

Capone, Douglas G.

172

Kentucky Geological Survey  

NSDL National Science Digital Library

In 1996 the Education Committee of the Kentucky Geological Survey, in conjunction with the Kentucky Society of Professional Geologists, established the Earth Science Education Network (ESEN). The network provided a group of geologists who served as resource persons for teachers, but has now been expanded to provide resources from around the globe. While primarily focusing on the geology of Kentucky, many of the online resources are applicable for educators throughout the U.S. There are links to Earth science topics and important websites, handouts and instructions for classroom demonstrations and activities, and also interesting information about Kentucky geology and publications.

173

Reply to Jones and Crowe: Correcting mistaken views of sedimentary geology, Mn-oxidation  

E-print Network

LETTER Reply to Jones and Crowe: Correcting mistaken views of sedimentary geology, Mn high, citing a reference for incorrect rocks: differ- ent lithologies, environments, process sedi margin deltaic sediments. Using correct sedimentary geology is important (2). In our report O2

Faraon, Andrei

174

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

175

Rhizosphere processes are quantitatively important components of terrestrial carbon and nutrient cycles.  

PubMed

While there is an emerging view that roots and their associated microbes actively alter resource availability and soil organic matter (SOM) decomposition, the ecosystem consequences of such rhizosphere effects have rarely been quantified. Using a meta-analysis, we show that multiple indices of microbially mediated C and nitrogen (N) cycling, including SOM decomposition, are significantly enhanced in the rhizospheres of diverse vegetation types. Then, using a numerical model that combines rhizosphere effect sizes with fine root morphology and depth distributions, we show that root-accelerated mineralization and priming can account for up to one third of the total C and N mineralized in temperate forest soils. Finally, using a stoichiometrically constrained microbial decomposition model, we show that these effects can be induced by relatively modest fluxes of root-derived C, on the order of 4% and 6% of gross and net primary production, respectively. Collectively, our results indicate that rhizosphere processes are a widespread, quantitatively important driver of SOM decomposition and nutrient release at the ecosystem scale, with potential consequences for global C stocks and vegetation feedbacks to climate. This article is protected by copyright. All rights reserved. PMID:25421798

Finzi, Adrien C; Abramoff, Rose Z; Spiller, Kimberly S; Brzostek, Edward R; Darby, Bridget A; Kramer, Mark A; Phillips, Richard P

2014-11-25

176

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.

Roger Steinberg

177

California Geological Survey: Geologic Maps  

NSDL National Science Digital Library

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

178

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

179

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

180

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

181

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.

182

Geological Time  

Microsoft Academic Search

IN his Presidential Address to Section C at Dover, Sir A. Geikie has offered a bold challenge to Lord Kelvin and those who agree with him by calling upon them to give due weight to geological phenomena in forming an estimate of geological time. Permit me to say what I think about it.

O. Fisher

1899-01-01

183

Yellowstone Geology  

NSDL National Science Digital Library

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

Park, Yellowstone N.

184

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

185

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

E-print Network

Geology Major www.geology.pitt.edu/undergraduate/geology.html Revised: 03/2013 Geology is a scientific discipline that aims to understand every aspect of modern and ancient Earth. A degree in geology the field of geology, environmental and geotechnical jobs exist for people with BS degrees. A master

Jiang, Huiqiang

186

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

187

Environmental Studies, Section III: Processes Through Time. Learning Carrel Lesson 6.7: Geologic Time. Study Guide and Script.  

ERIC Educational Resources Information Center

This is one of a series of 14 instructional components of a semester-long, environmental earth science course developed for undergraduate students. The course includes lectures, discussion sessions, and individualized learning carrel lessons. Presented are the study guide and script for a learning carrel lesson on geologic time. The slides,…

Boyer, Robert; And Others

188

The spatial distribution of heavy metals across the Arctic is related to local geology, natural processes, and anthro-  

E-print Network

The spatial distribution of heavy metals across the Arctic is related to local geology, natural, and the characteristics of the receptor compartments. The spatial distribution of heavy metals leading to biotic exposure concentration is a key step toward linking the sources of anthropogenic release of heavy metals, distribution

Ford, Jesse

189

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

E-print Network

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

Raja, Anita

190

Equal Learning Does Not Result in Equal Remembering: The Importance of Post-Encoding Processes  

ERIC Educational Resources Information Center

Explanations of variability in long-term recall typically appeal to encoding and/or retrieval processes. However, for well over a century, it has been apparent that for memory traces to be stored successfully, they must undergo a post-encoding process of stabilization and integration. Variability in post-encoding processes is thus a potential…

Bauer, Patricia J.; Guler, O. Evren; Starr, Rebecca M.; Pathman, Thanujeni

2011-01-01

191

Geologic evolution of Arizona  

SciTech Connect

Seven years in the making, the 35 papers in this volume summarize the stratigraphic, structural, and tectonic evolution of Arizona from Precambrian through Quaternary time. Intended as a compendium of current knowledge of Arizona geology, the papers synthesize previous work with new data, ideas, and concepts as well as identifying unresolved problems for future research. Emphasis is placed on the geologic evolution of the state as a whole rather than specific local areas. The papers are organized in terms of geologic eras: Proterozoic, Paleozoic, Mesozoic, and Cenozoic. The concluding section offers topical studies in the areas of geophysics, industrial minerals, uranium, oil and gas, geothermal resources, hydrogeology, and environmental geology. California readers will find much of interest in this research volume because many of the tectonic processes that formed Arizona also affected the development of this state.

Penny, J.P.; Reynolds, S.J. (eds.)

1989-01-01

192

Geologic hazards and Alaska's communities in a changing climate  

NASA Astrophysics Data System (ADS)

Observations indicate that changes in climate modify or intensify geomorphic processes in high-latitude regions. Changes in these processes can increase the magnitude and frequency of geologic hazards leading to casualties, damages to property and infrastructure, and a host of socio-economic problems. Numerous communities in Alaska are threatened by geologic hazards and are currently involved in adaptation or mitigation efforts to cope with these risks. In many communities, relocation is the preferred method for managing risk, but a lack of baseline geoscience data prohibits a sound evaluation of geologic hazards and recent landscape change and prevents informed community decision making. In an attempt to bridge this information gap, the Climate Change Hazards Program at the Alaska Division of Geological & Geophysical Surveys (DGGS) is collecting baseline geoscience data, quantifying landscape change, and conducting hazards assessments in and around imperiled communities in Alaska. An important and challenging step in each study is effectively communicating scientific results to community residents, other government agencies, and policy makers, which requires communication beyond peer-reviewed publications. Community visits, public meetings, and workshops are potentially important mechanism for disseminating important geologic hazards information to stakeholders in Alaska. Current DGGS pilot projects in the areas of Kivalina and Koyukuk illustrate the need for conducting geologic hazards assessments and properly disseminating scientific information.

Wolken, G. J.

2010-12-01

193

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

194

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

195

Geologic time  

USGS Publications Warehouse

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

Newman, William L.

2000-01-01

196

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

197

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

198

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

...products or by products, organisms, vectors, or germ plasm (embryos or semen) or to transport organisms or vectors1 Initial...Import or In Transit Permit (Animals, Animal Semen, Animal Embryos, Birds, Poultry, or Hatching Eggs).” 2...

2014-01-01

199

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

Code of Federal Regulations, 2010 CFR

...products or by products, organisms, vectors, or germ plasm (embryos or semen) or to transport organisms or vectors1 Initial...Import or In Transit Permit (Animals, Animal Semen, Animal Embryos, Birds, Poultry, or Hatching Eggs).” 2...

2010-01-01

200

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

Code of Federal Regulations, 2012 CFR

...products or by products, organisms, vectors, or germ plasm (embryos or semen) or to transport organisms or vectors1 Initial...Import or In Transit Permit (Animals, Animal Semen, Animal Embryos, Birds, Poultry, or Hatching Eggs).” 2...

2012-01-01

201

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

Code of Federal Regulations, 2011 CFR

...products or by products, organisms, vectors, or germ plasm (embryos or semen) or to transport organisms or vectors1 Initial...Import or In Transit Permit (Animals, Animal Semen, Animal Embryos, Birds, Poultry, or Hatching Eggs).” 2...

2011-01-01

202

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

Code of Federal Regulations, 2013 CFR

...products or by products, organisms, vectors, or germ plasm (embryos or semen) or to transport organisms or vectors1 Initial...Import or In Transit Permit (Animals, Animal Semen, Animal Embryos, Birds, Poultry, or Hatching Eggs).” 2...

2013-01-01

203

78 FR 18234 - Service of Process on Manufacturers; Manufacturers Importing Electronic Products Into the United...  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration...Agency's regulations. DATES: This rule is effective March 26, 2013 FOR FURTHER INFORMATION...procedure; Electronic product; Imports; Radiation protection; Surety bonds....

2013-03-26

204

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

205

Flash photoelectrochemical studies of transient electrode processes important in solar-energy conversion. Final report  

SciTech Connect

It has been the objective of this research program to apply electroanalytical and spectroscopic measurement techniques to the study of transient photolytic, photoemissive, and photoelectrolytic processes associated with uv-visible irradiation of an electrode/solution interface. Both semiconductor and metallic electrodes have been employed. For the characterization of transient phenomena, the general methodology of flash photolysis was employed (including both xenon flash lamp and tunable pulsed dye laser sources). The novel perspective afforded by transient electroanalytical/spectroscopic measurements of photoinitiated electrode processes has provided more definitive mechanistic insight to solar conversion phenomena in photogalvanic or photoelectrolysis processes.

Perone, S.P.

1982-10-01

206

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

NASA Technical Reports Server (NTRS)

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

Crumpler, L. S.

2003-01-01

207

Five Important Lessons I Learned during the Process of Creating New Child Care Centers  

ERIC Educational Resources Information Center

In this article, the author describes her experiences of developing new child care sites and offers five important lessons that she learned through her experiences which helped her to create successful child care centers. These lessons include: (1) Finding an appropriate area and location; (2) Creating realistic financial projections based on real…

Whitehead, R. Ann

2005-01-01

208

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

209

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

210

Chlorination processing of local planetary ores for oxygen and metallurgically important metals  

NASA Technical Reports Server (NTRS)

The use of chlorine to extract, reclaim, and purify metals has attractive possibilities for extraterrestrial processing of local planetary resources. While a complete cyclic process has been proposed for the recovery of metallurgically significant metals and oxygen, herein the chlorination step of the cycle is examined. An experimental apparatus for reacting refractory materials, such as ilmenite, in a microwave induced plasma is being built. Complex equilibria calculations reveal that stable refractory materials can, under the influence of a plasma, undergo chlorination and yield oxygen as a by-product. These issues and the potential advantages for plasma processing in space are reviewed. Also presented is a discussion of the complex equilibria program used in the analysis.

Lynch, D. C.

1989-01-01

211

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

212

The importance of establishing an international network of tissue banks and regional tissue processing centers.  

PubMed

During the past four decades, many tissue banks have been established across the world with the aim of supplying sterilized tissues for clinical use and research purposes. Between 1972 and 2005, the International Atomic Energy Agency supported the establishment of more than sixty of these tissue banks in Latin America and the Caribbean, Asia and the Pacific, Africa and Eastern Europe; promoted the use of the ionizing radiation technique for the sterilization of the processed tissues; and encouraged cooperation between the established tissue banks during the implementation of its program on radiation and tissue banking at national, regional and international levels. Taking into account that several of the established tissue banks have gained a rich experience in the procurement, processing, sterilization, storage, and medical use of sterilized tissues, it is time now to strengthen further international and regional cooperation among interested tissue banks located in different countries. The purpose of this cooperation is to share the experience gained by these banks in the procurement, processing, sterilization, storage, and used of different types of tissues in certain medical treatments and research activities. This could be done through the establishment of a network of tissue banks and a limited number of regional tissue processing centers in different regions of the world. PMID:23765095

Morales Pedraza, Jorge

2014-03-01

213

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

PubMed Central

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

2014-01-01

214

Pennsylvania Geology  

NSDL National Science Digital Library

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

215

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

NASA Technical Reports Server (NTRS)

The utilization of a cold plasma in chlorination processing is described. Essential equipment and instruments were received, the experimental apparatus assembled and tested, and preliminary experiments conducted. The results of the latter lend support to the original hypothesis: a cold plasma can both significantly enhance and bias chemical reactions. In two separate experiments, a cold plasma was used to reduce TiCl4 vapor and chlorinate ilmenite. The latter, reacted in an argon-chlorine plasma, yielded oxygen. The former experiment reveals that chlorine can be recovered as HCl vapor from metal chlorides in a hydrogen plasma. Furthermore, the success of the hydrogen experiments has lead to an analysis of the feasibility of direct hydrogen reduction of metal oxides in a cold plasma. That process would produce water vapor and numerous metal by-products.

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

1990-01-01

216

Reports of planetary geology program, 1983  

NASA Technical Reports Server (NTRS)

Several areas of the Planetary Geology Program were addressed including outer solar system satellites, asteroids, comets, Venus, cratering processes and landform development, volcanic processes, aeolian processes, fluvial processes, periglacial and permafrost processes, geomorphology, remote sensing, tectonics and stratigraphy, and mapping.

Holt, H. E. (compiler)

1984-01-01

217

Surficial Geologic Map of Maine  

NSDL National Science Digital Library

In this activity students become familiar with the nature and use of the Surficial Geologic Map of Maine and gain practice in using maps other than topographic maps. They will discover that surficial geology deals primarily with the geologically youthful, unconsolidated sedimentary materials that exist at, or close to the surface of a specific area and are important because the surface deposits filter and control the access of water to the water table. Students also learn that the study of surficial geology is important for siting of waste disposal facilities and for resources such as sand, gravel, and clay. Although this activity was written for a map of Maine, it will work in any state where surficial geological maps are available.

218

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

219

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

220

The Importance of Microphysical Processes in the Magnetosphere-Ionosphere System  

NASA Astrophysics Data System (ADS)

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

Lotko, W.

2012-12-01

221

Geological flows  

E-print Network

In this paper geology and planetology are considered using new conceptual basis of high-speed flow dynamics. Recent photo technics allow to see all details of a flow, 'cause the flow is static during very short time interval. On the other hand, maps and images of many planets are accessible. Identity of geological flows and high-speed gas dynamics is demonstrated. There is another time scale, and no more. All results, as far as the concept, are new and belong to the author. No formulae, pictures only.

Yu. N. Bratkov

2008-11-19

222

Heat Conduction: An Important Process for the Shape of Iapetus's Dark Spots?  

NASA Astrophysics Data System (ADS)

The saturnian moon Iapetus is famous for its global black-and-white dichotomy. While its leading side (Cassini Regio) is covered by very dark material, the poles and trailing side are relatively bright. However, craters and troughs with dark floors are located within the bright area, especially at low latitudes. The boundaries of these smaller-scaled dark areas are very sharp. Even within the best-resolved images from the Cassini imaging experiment (ISS), the typical length of a drop-off in albedo is below the resolution limit. Thermal segregation, driven by a feedback process, has been proposed as the cause for the global dichotomy (Spencer and Denk 2010; Denk et al. 2010). In addition, for local features like craters and troughs, we explain the local darkening by an increased amount of insolation caused by the concave curvature of these features. We studied the insolation geometry using varying reflectance models. A model of linear interpolation between lunar and Lambert-like scattering reproduces the dark patterns relatively well. However, the increased insolation by itself neither explains the abundance of darkened terrain, nor the temporal behavior of darkening of fresh bright craters from the outside inward within the Cassini Regio area. A comparison of time scales and spatial scales shows that heat conduction might act as a major contributor to the growth of local dark areas within the bright terrain, despite its short range. Due to the repetitive nature of the processes needed for the growth of darkened terrain, the significant processes should not be as long-ranged as saltation of ice or CO2. We gratefully acknowledge funding of this work by the German Space Agency (DLR) Bonn through grant no. 50 OH 0305.

Galuba, Goetz; Denk, T.; Neukum, G.

2010-10-01

223

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

E-print Network

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

Lanterman, Aaron

224

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

E-print Network

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

Haase, Markus

225

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

226

Directions of the US Geological Survey Landslide Hazards Reduction Program  

USGS Publications Warehouse

The US Geological Survey (USGS) Landslide Hazards Reduction Program includes studies of landslide process and prediction, landslide susceptibility and risk mapping, landslide recurrence and slope evolution, and research application and technology transfer. Studies of landslide processes have been recently conducted in Virginia, Utah, California, Alaska, and Hawaii, Landslide susceptibility maps provide a very important tool for landslide hazard reduction. The effects of engineering-geologic characteristics of rocks, seismic activity, short and long-term climatic change on landslide recurrence are under study. Detailed measurement of movement and deformation has begun on some active landslides. -from Author

Wieczorek, G.F.

1993-01-01

227

The importance of being supercoiled: how DNA mechanics regulate dynamic processes.  

PubMed

Through dynamic changes in structure resulting from DNA-protein interactions and constraints given by the structural features of the double helix, chromatin accommodates and regulates different DNA-dependent processes. All DNA transactions (such as transcription, DNA replication and chromosomal segregation) are necessarily linked to strong changes in the topological state of the double helix known as torsional stress or supercoiling. As virtually all DNA transactions are in turn affected by the torsional state of DNA, these changes have the potential to serve as regulatory signals detected by protein partners. This two-way relationship indicates that DNA dynamics may contribute to the regulation of many events occurring during cell life. In this review we will focus on the role of DNA supercoiling in the cellular processes, with particular emphasis on transcription. Besides giving an overview on the multiplicity of factors involved in the generation and dissipation of DNA torsional stress, we will discuss recent studies which give new insight into the way cells use DNA dynamics to perform functions otherwise not achievable. This article is part of a Special Issue entitled: Chromatin in time and space. PMID:22233557

Baranello, Laura; Levens, David; Gupta, Ashutosh; Kouzine, Fedor

2012-07-01

228

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

NASA Astrophysics Data System (ADS)

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

Brand, John Richard

229

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.

230

Geologic Time  

NSDL National Science Digital Library

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

Heaton, Timothy

231

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)

232

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

233

Spray granulation: importance of process parameters on in vitro and in vivo behavior of dried nanosuspensions.  

PubMed

The use of fluid bed granulation for drying of pharmaceutical nanoparticulates on micron-sized granule substrates is a relatively new technique, with limited understanding in the current literature of the effects of process parameters on the physical properties of the dried nanoparticle powders. This work evaluated the effects of spray mode, spray rate and atomizing pressure for spray granulation of drug nanosuspensions through a systematic study. Naproxen and a proprietary Novartis compound were converted into nanosuspensions through wet media milling and dried onto a mannitol based substrate using spray granulation. For naproxen, various physical properties of the granules, as well as the in vitro re-dispersion and dissolution characteristics of the nano-crystals, were measured. It was found that the spray mode had the most drastic effect, where top spray yielded smaller re-dispersed particle sizes and faster release rates of drug from granules than bottom spray. This was attributed to the co-current spraying in bottom spray resulting in denser, homogenous films on the substrate. Similar in vitro results were obtained for the proprietary molecule, Compound A. In vivo studies in beagle dogs with Compound A showed no significant difference between the liquid and the dried forms of the nanosuspension in terms of overall AUC, differences were observed in the tmax which correlated with the rank ordering observed from the in vitro dissolution profiles. These findings make spray granulation amenable to the production of powders with desired processing and handling properties, without compromising the overall exposure of the compound under investigation. PMID:23916460

Figueroa, Carlos E; Bose, Sonali

2013-11-01

234

Transcriptional Regulation of Important Cellular Processes in Skeletal Myogenesis Through Interferon-?.  

PubMed

The purpose of the present study was to investigate the effect of interferon (IFN)-? on the transcriptomic profile of differentiating mouse C2C12 myogenic cells. Global gene expression was evaluated using whole mouse genome oligonucleotide microarrays, and the results were validated through real-time PCR. IFN-? (1?ng/mL) increased myoblast proliferation but decreased cell respiration and myosin heavy chain content and slightly decreased the fusion index in differentiating C2C12 cell cultures. The genes upregulated through IFN-? were involved in cell cycle; regulation of cell proliferation; programmed cell death; chemotaxis; and cytokine, growth factor, and peptidase activity, whereas the genes downregulated through IFN-? primarily contributed to the regulation of transcription, cell-cell signaling, nitrogen compound biosynthesis, ser/thr protein kinase signaling, and regulation of the Wnt pathway. In conclusion, IFN-? affects the expression of numerous genes associated with the regulation of several processes in myogenesis. The effects of IFN-? on cellular transcription include (1) alteration of cytokine/growth factor expression, promoting cell proliferation and migration but inhibiting differentiation, (2) impairment of pro-myogenic transcription, (3) disruption of cell adhesion and sarcolemma/cytoskeleton organization, and (4) increased peptidase activity leading to enhanced proteolysis and apoptosis. PMID:25237846

Grzelkowska-Kowalczyk, Katarzyna; Wicik, Zofia; Majewska, Alicja; Tokarska, Justyna; Grabiec, Kamil; Koz?owski, Marcin; Milewska, Marta; B?aszczyk, Maciej

2015-02-01

235

Sedimentary RocksSedimentary Rocks Geology 200  

E-print Network

Sedimentary RocksSedimentary Rocks Geology 200 Geology for Environmental ScientistsGeology for Environmental Scientists #12;Major Concepts · Sedimentary rocks form by the processes of weathering, erosion · Sedimentary structures are critical to interpreting sedimentary rocks. #12;The Rock CycleThe Rock Cycle #12

Kammer, Thomas

236

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.

Stephen Nelson

237

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

PubMed Central

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

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

2014-01-01

238

The Emerging Medical and Geological Association  

PubMed Central

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

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

2005-01-01

239

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

240

Introduction to ore geology  

SciTech Connect

This textbook on ore geology is for second and third year undergraduates and closely parallels the undergraduate course given in this subject at England's University of Leicester. The volume covers three major areas: (1) principles of ore geology, (2) examples of the most important types of ore deposits, and (3) mineralization in space and time. Many chapters have been thoroughly revised for this edition and a chapter on diamonds has been added. Chapters on greisen and pegmatite have also been added, the former in response to the changing situation in tin mining following the recent tin crisis, and the latter in response to suggestions from geologists in a number of overseas countries. Some chapters have been considerably expanded and new sections added, including disseminated gold deposits and unconformity-associated uranium deposits. The author also expands on the importance of viewing mineral deposits from an economic standpoint.

Evans, A.M.

1987-01-01

241

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

PubMed Central

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

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

2014-01-01

242

Significant achievements in the Planetary Geology Program  

Microsoft Academic Search

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;

J. W. Head

1978-01-01

243

Controlled-source Electromagnetic Responses of Spatially Hierarchial Geological Media  

NASA Astrophysics Data System (ADS)

The controlled-source electromagnetic (CSEM) induction technique is gaining importance as a valuable near-surface geophysical tool for hydrogeophysical site assessment. However, CSEM responses are oftentimes difficult to interpret owing to the complexity of the host geological environmemnt. Bedding planes, joints, fracture zones, and other geological features conspire to generate a medium in which electrical conductivity is variable over a hierarchy of spatial scales. Rocks at each length scale offer different patterns of heterogeneity that reflect the complex interplay of their formative geological processes. The result is a rough, spatially hierarchial geological structure that leaves a similar imprint on the electrical conductivity structure. Even though CSEM induction obeys diffusive physics and is therefore inherently a smoothing operation, observed CSEM responses from a variety of geological settings have in common very rough spatial variability. In fact, CSEM profiles invariably are examples of fractional Brownian motion (fBm) signals. Existing algorithms for forward modeling of CSEM responses solve however the governing Maxwell equations in piecewise constant gridblocks of electrical conductivity. This pragmatic view of the subsurface electrical structure is outdated and inaccurate. The purpose of my presentation is to introduce hydrogeophysicists to the fractal nature of observed CSEM responses and to develop new concepts in forward modeling taking into account rough, spatially hierachial electrical conductivity structures. The CSEM response of man-made, non-fractal objects embedded in a fractal geological medium is also discussed in the context of target detection and discrimination algorithms. Practical applications to problems in applied hydrogeophysical investigations are emphasized.

Everett, M. E.

2002-12-01

244

Genome-Wide Functional Profiling Identifies Genes and Processes Important for Zinc-Limited Growth of Saccharomyces cerevisiae  

PubMed Central

Zinc is an essential nutrient because it is a required cofactor for many enzymes and transcription factors. To discover genes and processes in yeast that are required for growth when zinc is limiting, we used genome-wide functional profiling. Mixed pools of ?4,600 deletion mutants were inoculated into zinc-replete and zinc-limiting media. These cells were grown for several generations, and the prevalence of each mutant in the pool was then determined by microarray analysis. As a result, we identified more than 400 different genes required for optimal growth under zinc-limiting conditions. Among these were several targets of the Zap1 zinc-responsive transcription factor. Their importance is consistent with their up-regulation by Zap1 in low zinc. We also identified genes that implicate Zap1-independent processes as important. These include endoplasmic reticulum function, oxidative stress resistance, vesicular trafficking, peroxisome biogenesis, and chromatin modification. Our studies also indicated the critical role of macroautophagy in low zinc growth. Finally, as a result of our analysis, we discovered a previously unknown role for the ICE2 gene in maintaining ER zinc homeostasis. Thus, functional profiling has provided many new insights into genes and processes that are needed for cells to thrive under the stress of zinc deficiency. PMID:22685415

Loguinov, Alex V.; Zimmerman, Ginelle R.; Vulpe, Chris D.; Eide, David J.

2012-01-01

245

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

246

Transcription factor and microRNA co-regulatory loops: important regulatory motifs in biological processes and diseases.  

PubMed

Transcription factors (TFs) and microRNAs (miRNAs) can jointly regulate target gene expression in the forms of feed-forward loops (FFLs) or feedback loops (FBLs). These regulatory loops serve as important motifs in gene regulatory networks and play critical roles in multiple biological processes and different diseases. Major progress has been made in bioinformatics and experimental study for the TF and miRNA co-regulation in recent years. To further speed up its identification and functional study, it is indispensable to make a comprehensive review. In this article, we summarize the types of FFLs and FBLs and their identified methods. Then, we review the behaviors and functions for the experimentally identified loops according to biological processes and diseases. Future improvements and challenges are also discussed, which includes more powerful bioinformatics approaches and high-throughput technologies in TF and miRNA target prediction, and the integration of networks of multiple levels. PMID:24307685

Zhang, Hong-Mei; Kuang, Shuzhen; Xiong, Xushen; Gao, Tianliuyun; Liu, Chenglin; Guo, An-Yuan

2015-01-01

247

Importance of the subgrid-scale turbulent moist process: Cloud distribution in global cloud-resolving simulations  

NASA Astrophysics Data System (ADS)

This study investigated the turbulent transport process within the nonhydrostatic icosahedral atmospheric model (NICAM), a global cloud-resolving model (GCRM), with particular focus on the spatial reproducibility of cloud characteristics in NICAM simulations. A turbulent closure model was applied, based on level 2 of the model developed by Nakanishi and Niino ([Nakanishi, M., and Niino, H., 2006: An improved Mellor-Yamada level-3 model: its numerical stability and application to a regional prediction of advection fog. Boundary-Layer Meteorol., 119, 397-407.]; a revised version of the original Mellor-Yamada model), together with a subgrid-scale condensation process. NICAM simulations were conducted for boreal summer of 2004 using mesh sizes of about 14 km and 7 km. Simulated cloud amounts and radiative budget were compared with observed data. The results confirmed an improvement in the spatial distribution of low clouds that develop in offshore regions of subtropical continents compared to past NICAM experiments ([Iga, S., Tomita, H., Tsushima, Y., and Satoh, M., 2007: Climatology of a nonhydrostatic global model with explicit cloud process. Geophys. Res. Lett., 34, L22814, doi:10.1029/2007/GL031048.]). A sensitivity study of subgrid-scale clouds in the turbulent closure scheme revealed that the turbulent transport process modulated by the subgrid-scale cloud strongly controls not only the low-cloud amount but also mid- and high-cloud amounts. This indicates that parameterization of unresolvable subgrid-scale clouds remains an important component of cloud behavior in GCRMs.

Noda, Akira T.; Oouchi, Kazuyoshi; Satoh, Masaki; Tomita, Hirofumi; Iga, Shin-ichi; Tsushima, Yoko

2010-05-01

248

Europa: Geological activity and surface - subsurface exchange  

NASA Astrophysics Data System (ADS)

Jupiter's moon Europa has a geologically young surface, allowing the possibility of current, ongoing geological activity. We are searching the Galileo database for overlapping images taken during the 5-year mission, and are comparing images using an iterative coregistration technique to look for changes due to geological activity. We will also discuss methods by which such activity could occur on Europa. We are particularly interested in the ability of geological processes to bring surface material down into the subsurface, and to bring subsurface material up to the surface. We are continuing a survey of such processes, including endogenic tectonic and cryovolcanic activity, and exogenic processes such as gardening and impact cratering.

Phillips, C. B.; Cowell, W.

2005-12-01

249

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

Microsoft Academic Search

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

Mary Jo Baedecker

250

Geological Survey research, 1975  

USGS Publications Warehouse

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

U.S. Geological Survey

1975-01-01

251

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

252

Geologic Technician New Curriculum  

ERIC Educational Resources Information Center

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

Karp, Stanley E.

1970-01-01

253

Community Perceptions of Geologic Sequestration  

NASA Astrophysics Data System (ADS)

Political momentum for mitigating climate change through the use of large-scale energy technologies such as geologic sequestration is growing. This paper explores the views of communities living near an actual or potential geologic sequestration project site. Given the potential importance of geologic sequestration to U.S. energy policy, what might explain and influence the views of this technology by the community-members. Through focus groups and one-on-one interviews, we gathered the views of two communities in California's Central Valley. One community close to a Department of Energy sponsored geologic sequestration pilot-project and another similarly located community that is not actually a project site. Our analysis combined a review of the history of the communities with other technologies and their social and economic indicators with the results of the focus groups and interviews. The results suggest that the sense of community empowerment, as contextualized by the history of the community and socio-economic indicators, is an important indicator of positive views of geologic sequestration. In addition, the results indicate community members prefer to be informed about geologic sequestration from a variety of sources (e.g., academia and industry).

Wong-Parodi, G. M.; Farrell, A.; Ray, I.

2007-12-01

254

Geodiversity: Exploration of 3D geological model space  

NASA Astrophysics Data System (ADS)

The process of building a 3D model necessitates the reconciliation of field observations, geophysical interpretation, geological data uncertainty and the prevailing tectonic evolution hypotheses and interpretations. Uncertainty is compounded when clustered data points collected at local scales are statistically upscaled to one or two points for use in regional models. Interpretation is required to interpolate between sparse field data points using ambiguous geophysical data in covered terranes. It becomes clear that multiple interpretations are possible during model construction. The various interpretations are considered as potential natural representatives, but pragmatism typically dictates that just a single interpretation is offered by the modelling process. Uncertainties are introduced into the 3D model during construction from a variety of sources and through data set optimisation that produces a single model. Practices such as these are likely to result in a model that does not adequately represent the target geology. A set of geometrical ‘geodiversity’ metrics are used to analyse a 3D model of the Gippsland Basin, southeastern Australia after perturbing geological input data via uncertainty simulation. The resulting sets of perturbed geological observations are used to calculate a suite of geological 3D models that display a range of geological architectures. The concept of biodiversity has been adapted for the geosciences to quantify geometric variability, or geodiversity, between models in order to understand the effect uncertainty has models geometry. Various geometrical relationships (depth, volume, contact surface area, curvature and geological complexity) are used to describe the range of possibilities exhibited throughout the model suite. End-member models geodiversity metrics are classified in a similar manner to taxonomic descriptions. Further analysis of the model suite is performed using principal component analysis (PCA) to determine important geometrical characteristics. The configuration of the model space is determined through identifying ‘outlier’ model examples, which potentially represent undiscovered model ‘species’.

Lindsay, M. D.; Jessell, M. W.; Ailleres, L.; Perrouty, S.; de Kemp, E.; Betts, P. G.

2013-05-01

255

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, William P.; Edgar, N.T.; Scanlon, K.M.; Klitgord, Kim D.

1987-01-01

256

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

257

Geology of Wisconsin  

NSDL National Science Digital Library

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

Steven Dutch

1997-09-10

258

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

259

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

Code of Federal Regulations, 2010 CFR

...manufacture, process, distribute...commerce, or use chemicals containing...manufacture, process, distribute...commerce, or use chemicals containing...manufacture, process, distribute...commerce, or use chemicals...

2010-07-01

260

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

Code of Federal Regulations, 2011 CFR

...manufacture, process, distribute...commerce, or use chemicals containing...manufacture, process, distribute...commerce, or use chemicals containing...manufacture, process, distribute...commerce, or use chemicals...

2011-07-01

261

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

262

Visible Geology - Interactive online geologic block modelling  

NASA Astrophysics Data System (ADS)

Geology is a highly visual science, and many disciplines require spatial awareness and manipulation. For example, interpreting cross-sections, geologic maps, or plotting data on a stereonet all require various levels of spatial abilities. These skills are often not focused on in undergraduate geoscience curricula and many students struggle with spatial relations, manipulations, and penetrative abilities (e.g. Titus & Horsman, 2009). A newly developed program, Visible Geology, allows for students to be introduced to many geologic concepts and spatial skills in a virtual environment. Visible Geology is a web-based, three-dimensional environment where students can create and interrogate their own geologic block models. The program begins with a blank model, users then add geologic beds (with custom thickness and color) and can add geologic deformation events like tilting, folding, and faulting. Additionally, simple intrusive dikes can be modelled, as well as unconformities. Students can also explore the interaction of geology with topography by drawing elevation contours to produce their own topographic models. Students can not only spatially manipulate their model, but can create cross-sections and boreholes to practice their visual penetrative abilities. Visible Geology is easy to access and use, with no downloads required, so it can be incorporated into current, paper-based, lab activities. Sample learning activities are being developed that target introductory and structural geology curricula with learning objectives such as relative geologic history, fault characterization, apparent dip and thickness, interference folding, and stereonet interpretation. Visible Geology provides a richly interactive, and immersive environment for students to explore geologic concepts and practice their spatial skills.; Screenshot of Visible Geology showing folding and faulting interactions on a ridge topography.

Cockett, R.

2012-12-01

263

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.

264

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

265

GEOLOGICAL CHARACTERISTICS  

E-print Network

CAPSULE DESCRIPTION: Ilmenite, hemo-ilmenite or titaniferous magnetite accumulations as cross-cutting lenses or dike-like bodies, Ia> ers or disseminations within anorthositiclgabbroicinoritic rocks. These deposits can be subdivided into an ilmenite subtype (anorthosite-hosted titanium-iron) and a titaniferous magnetite subtype (gabbro-anorthosite-hosted iron-titanium). TECTONIC SETTING: Commonly associated with anorthosite-gabbro-norite-monzonite (mangerite)charnockite granite (AMCG) suites that are conventionally interpreted to be anorogenic and/or extensional. Some of the iron-titanium deposits occur at continental margins related to island arc magmatism followed by an episode of erogenic compression. DEPOSITIONAL ENVIRONMENT i GEOLOGICAL SETTING: Deposits occur in intrusive complexes which typically are emplaced at deeper levels in the crust. Progressive differentiation of liquids residual from anorthosite-norite magmas leads to late stage intrusions enriched in Fe and Ti oxides and apatite. AGE OF MINERALIZATION: Mainly Mesoproterozoic (1.65 to 0.90 Ga) for the ihnenite deposits, but this may be a consequence of a particular combination of tectonic circumstances, rather than any a priori temporal control. The Fe-Ti deposits with titaniferous magnetite do not appear to be restricted in time. HOST/ASSOCIATED ROCKS: Hosted by massive, layered or zoned intrusive complexes- anorthosite, norite,

G. A. Gross; C. F. Gower; D. V. Lefebure; Commodities (byproducts) Ti

266

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

NASA Astrophysics Data System (ADS)

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

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

2008-02-01

267

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

USGS Publications Warehouse

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

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

2013-01-01

268

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

NSDL National Science Digital Library

This US Geological Survey Open-File Report (00-212) describes analytical techniques for benthic macroinvertebrates. Available in .pdf format, the 49-page report includes information on such analytical techniques as chemical equipment supplies, taxonomic identification, and more.

2000-01-01

269

REMOTE SENSING GEOLOGICAL SURVEY  

E-print Network

REMOTE SENSING IN GEOLOGICAL SURVEY OF BRAZIL August/2010 Mônica Mazzini Perrotta Remote Sensing Division Head #12;SUMMARY The Geological Survey of Brazil mission The Remote Sensing Division Main remote sensing data used in CPRM geologic projects Future perspective: the Spectral Library of Geological Survey

270

History of Geology.  

ERIC Educational Resources Information Center

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

Greene, Mott T.

1985-01-01

271

GEOLOGY (GEOL) Robinson Foundation  

E-print Network

177Geology GEOLOGY (GEOL) Robinson Foundation PROFESSOR HARBOR ASSOCIATE PROFESSORS KNAPP, CONNORS ASSISTANT PROFESSORS GREER, RAHL MAJORS BACHELOR OF SCIENCE A major in geology leading to a Bachelor of Science degree consists of 50 credits as follows: 1. Geology 160, 185, 211, 311, 330, 350

Dresden, Gregory

272

Tennessee Division of Geology  

NSDL National Science Digital Library

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

273

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

274

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

275

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

PubMed Central

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

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

2011-01-01

276

10 CFR 63.112 - Requirements for preclosure safety analysis of the geologic repository operations area.  

Code of Federal Regulations, 2010 CFR

...and process activities at the geologic repository operations area...human-induced hazards at the geologic repository operations area...human-induced hazards at the geologic repository operations area... (2) Means to limit the time required to perform work...

2010-01-01

277

Vermont Geological Survey  

NSDL National Science Digital Library

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

278

Oklahoma Geological Survey  

NSDL National Science Digital Library

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

279

Geological SciencesGeological Sciences Geological EngineeringGeological Engineering  

E-print Network

of environmental science and geo-hazards (e.g. earthquakes). Queen's University has one of the largest dedicated scientists study the Earth, its rock record, and the processes (e.g. volcanism, sedimentation, glaciation

Ellis, Randy

280

GWM-a ground-water management process for the U.S. Geological Survey modular ground-water model (MODFLOW-2000)  

USGS Publications Warehouse

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 management formulations. Each management formulation consists of a set of decision variables, an objective function, and a set of constraints. Three types of decision variables are supported by GWM: flow?rate decision variables, which are withdrawal or injection rates at well sites; external decision variables, which are sources or sinks of water that are external to the flow model and do not directly affect the state variables of the simulated ground?water system (heads, streamflows, and so forth); and binary variables, which have values of 0 or 1 and are used to define the status of flow?rate or external decision variables. Flow?rate decision variables can represent wells that extend over one or more model cells and be active during one or more model stress periods; external variables also can be active during one or more stress periods. A single objective function is supported by GWM, which can be specified to either minimize or maximize the weighted sum of the three types of decision variables. Four types of constraints can be specified in a GWM formulation: upper and lower bounds on the flow?rate and external decision variables; linear summations of the three types of decision variables; hydraulic?head based constraints, including drawdowns, head differences, and head gradients; and streamflow and streamflow?depletion constraints. The Response Matrix Solution (RMS) Package of GWM uses the Ground?Water Flow Process of MODFLOW to calculate the change in head at each constraint location that results from a perturbation of a flow?rate variable; these changes are used to calculate the response coefficients. For linear management formulations, the resulting matrix of response coefficients is then combined with other components of the linear management formulation to form a complete linear formulation; the formulation is then solved by use of the simplex algorithm, which is incorporated into the RMS Package. Nonlinear formulations arise for simulated conditions that include water?table (unconfined) aquifers or head?dependent boundary conditions (such as streams, drains, or evapotranspiration from the water table). Nonlinear formulations are solved by sequential linear programming; that is, repeated linearization of the nonlinear features of the management problem. In this approach, response coefficients are recalculated for each iteration of the solution process. Mixed?binary linear (or mildly nonlinear) formulations are solved by use of the branch and bound algorithm, which is also incorporated into the RMS Package. Three sample problems are provided to demonstrate the use of GWM for typical ground?water flow management problems. These sample problems provide examples of how GWM input files are constructed to specify the decision variables, objective function, constraints, and solution process for a GWM run. The GWM Process runs with the MODFLOW?2000 Global and Ground?Water Flow Processes, but in its current form GWM cannot be used with the Observation, Sensitivity, Parameter?Estimation, or Ground?Water Transport Processes. The GWM Process is written with a modular structure so that new objective functions, constraint types, and solution algorithms can be added.

Ahlfeld, David P.; Barlow, Paul M.; Mulligan, Anne E.

2005-01-01

281

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

282

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

283

13 CFR 120.1821 - What is the process to obtain designation as a Systemically Important Secondary Market Broker...  

Code of Federal Regulations, 2010 CFR

...designation as a Systemically Important Secondary Market Broker-Dealer? 120.1821 Section...Program for Systemically Important Secondary Market Broker-Dealers (SISMBD Loan Program...designation as a Systemically Important Secondary Market Broker-Dealer? (a) SBA will...

2010-01-01

284

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

285

National Park Service: Tour of Park Geology  

NSDL National Science Digital Library

The tour of Park geologic resources includes pages specific to individual National Parks, Monuments, Recreation Areas, Preserves, Seacoasts, Reserves, and Recreation Areas. These pages are indexed by park name, state, or by one of the following topics: basin and range, caves, Colorado Plateau, fossils, glaciers, hot springs, human use, mountain building, oldest rocks, plate tectonics, river systems, sand dunes, shoreline geology, or volcanoes. Organization of each of the pages typically follows a NPS template with categories for park geology, maps, photographs, geologic research, related links, visitor information, multimedia, and "teacher features" (educational resources and links for teaching geology with National Park examples.) Common subjects that are addressed at various park sites include: minerals, rocks, fossils, cave and karst systems, coastlines, glaciers, volcanoes, faults, landforms, landslides, structures, fluvial systems, sediments, soils, stratigraphic relations, processes that form or act on geologic features and their chemical compositions, and the history of the planet and its life forms.

286

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.

287

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.

288

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

289

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

SciTech Connect

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 im20 pact 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. L.; Rajagopalan, K.; Chung, S. H.; Jiang, X.; Harrison, J. H.; Nergui, T.; Guenther, Alex B.; Miller, C.; Reyes, J.; Tague, C. L.; Choate, J. S.; Salathe, E.; Stockle, Claudio O.; Adam, J. C.

2014-05-16

290

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

291

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

292

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.

293

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

294

Utah Geological Survey: Teaching Geology Resources  

NSDL National Science Digital Library

From Arches National Park to the towering cliffs at Castle Rock Campground, Utah has some remarkable geology on display. The Utah Geological Survey decided to draw on these fantastic "outdoor laboratories" and create a set of resources designed for science educators. While some of the resources are geared towards users in Utah, many of the sections contain helpful overviews that will help all educators remain on a steady foundation of geologic knowledge. One key area on the site is the "Earthquakes & Geologic Hazards" section. Here, visitors can find well-composed and straight forward summaries on topics like liquefaction, ground cracks, and fault lines. Moving on to the "Teacher Resources" area, visitors will find the delightful "Glad You Asked" articles and the very useful "Teacher's Corner" column which provides information on reading a stone wall and geologic stretching.

295

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

296

Geologic Hazards: Geomagnetism  

NSDL National Science Digital Library

Anyone researching or interested in geomagnetism will appreciate the US Geological Survey's Geologic Hazards: Geomagnetism Web site. Visitors will find research publications, various downloadable magnetic charts, models, data plots, an online calculator for magnetic fields, and more.

1997-01-01

297

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

298

Protein-protein interactions play important roles in a variety of cellular processes. The lifetime and the affinity of a protein complex are well correlated with its  

E-print Network

143 Summary Protein-protein interactions play important roles in a variety of cellular processes. The lifetime and the affinity of a protein complex are well correlated with its function in a process. Transient interactions between electron transfer proteins are of great interests because a fast association

van den Brink, Jeroen

299

Petroleum geology of Tunisia  

SciTech Connect

Recent discoveries and important oil shows have proven the existence of hydrocarbons in newly identified depocenters and reservoirs. In general, except for some areas around the producing fields, Tunisia is largely underdrilled. The national company ETAP has decided to release data and to publish a synthesis on the petroleum geology of Tunisia. The geology of Tunisia provides a fine example of the contrast between Alpine folding, which typifies northern Tunisia and the African craton area of the Saharan part. Eastern Tunisia corresponds to an unstable platform forming plains or low hills and extending eastwards to the shallow Pelagian Sea. There are a wide variety of basins: central and northern Tunisia represents a front basin the Saharan Ghadames basin or the Chott trough are sag basins; the Gulf of Gabes was formed as a distension margin the Gulf of Hammamet is a composite basin and several transversal grabens cut across the country, including offshore, and are rift-type basins. All these features are known to be oil prolific throughout the world. Two large fields and many modest-size pools are known in Tunisia. Oil and gas fields in the surrounding countries, namely the Saharan fields of Algeria and Libya the large Bouri field offshore Tripolitania and discoveries in the Italian part of the Straits of Sicily, suggest a corresponding potential in Tunisia. Exposed paleogeographic and structural maps, balanced sections, and examples of fields and traps will support an optimistic evaluation of the future oil exploration in Tunisia.

Burollet, P.F. (CIFEG, Paris (France)); Ferjami, A.B.; Mejri, F. (ETAP, Tunis (Tunisia))

1990-05-01

300

Physiography, geology, and land cover of four watersheds in eastern Puerto Rico: Chapter A in Water quality and landscape processes of four watersheds in eastern Puerto Rico  

USGS Publications Warehouse

Four watersheds with differing geology and land cover in eastern Puerto Rico have been studied on a long-term basis by the U.S. Geological Survey to evaluate water, energy, and biogeochemical budgets. These watersheds are typical of tropical, island-arc settings found in many parts of the world. Two watersheds are located on coarse-grained granitic rocks that weather to quartz- and clay-rich, sandy soils, and two are located on fine-grained volcanic rocks and volcaniclastic sedimentary rocks that weather to quartz-poor, fine-grained soils. For each bedrock type, one watershed is covered with mature forest, and the other watershed, like most of Puerto Rico, has transformed from relatively undisturbed pre-European forest to intensive agriculture in the 19th and early 20th centuries, and further to ongoing reforestation that began in the middle of the 20th century. The comparison of water chemistry and hydrology in these watersheds allows an evaluation of the effects of land-use history and geology on hydrologic regimes and erosion rates. This chapter describes the physiography, geology, and land cover of the four watersheds and provides background information for the remaining chapters in this volume.

Murphy, Sheila F.; Stallard, Robert F.; Larsen, Matthew C.; Gould, William A.

2012-01-01

301

Geologic Sequestration of Carbon Dioxide  

NASA Astrophysics Data System (ADS)

Geologic sequestration of carbon dioxide has emerged as one of the most promising options for making deep cuts in carbon dioxide emissions. Geologic sequestration involves the two-step process of first capturing carbon dioxide by separating it from stack emissions, followed by injection and long term storage in deep geologic formations. Sedimentary basins, including depleted oil and gas reservoirs, deep unminable coal seams, and brine-filled formations, provide the most attractive storage reservoirs. Over the past few years significant advances have been made in this technology, including development of simulation models and monitoring systems, implementation of commercial scale demonstration projects, and investigation of natural and industrial analogues for geologic storage of carbon dioxide. While much has been accomplished in a short time, there are many questions that must be answered before this technology can be employed on the scale needed to make significant reductions in carbon dioxide emissions. Questions such as how long must the carbon dioxide remain underground, to what extent will geochemical reactions completely immobilize the carbon dioxide, what can be done in the event that a storage site begins to leak at an unacceptable rate, what is the appropriate risk assessment, regulatory and legal framework, and will the public view this option favorably? This paper will present recent advances in the scientific and technological underpinnings of geologic sequestration and identify areas where additional information is needed.

Benson, S. M.

2003-04-01

302

Planetary geology  

NASA Technical Reports Server (NTRS)

The solar system is considered along with the significance of meteorites as samples of the universe, the origin of planets, and earth's-eye view of the moon, previews of the lunar surface, aspects of impact cratering, lunar igneous processes, the mapping of the moon, the exploration of the moon in connection with the Apollo lunar landings, and the scientific payoff from the lunar samples. Studies of Mars, Venus, and the planets beyond are discussed, taking into account the Mariner Mars program, the Mariner orbiting mission, missions to Venus, the Mariner flight to Mercury, and the Pioneer missions. Attention is also given to the origin of the moon, implications of the moon's thermal history, similarities and differences in planetary evolution, and the role of internal energy in planetary development.

Short, N. M.

1975-01-01

303

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

304

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.

305

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

PubMed Central

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

Ohashi, Haruka; Hoshino, Yoshinobu

2014-01-01

306

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.

307

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

ERIC Educational Resources Information Center

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

Anchorage School District, AK.

308

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.

Trileigh Tucker

309

Inverse Modelling in Geology by Interactive Evolutionary Computation  

E-print Network

Inverse Modelling in Geology by Interactive Evolutionary Computation Chris Wijns a,b,, Fabio of geological processes, in the absence of established numerical criteria to act as inversion targets, requires evolutionary computation provides for the inclusion of qualitative geological expertise within a rigorous

Boschetti, Fabio

310

MAJOR TO CAREER GUIDE B.S. Geology  

E-print Network

MAJOR TO CAREER GUIDE B.S. Geology College of Sciences geoscience.unlv.edu/ Mission of the College: MPE-A 130 www.unlv.edu/sciences/advising About the Geology Career Geoscientists are stewards understanding of Earth processes and history. Value of the Geology Degree Opportunities for interesting

Walker, Lawrence R.

311

Geologic Maps and Structures Name ______________________________ Geology 100 Harbor section  

E-print Network

Geologic Maps and Structures Name ______________________________ Geology 100 ­ Harbor section The objectives of this lab are for you to learn the basic geologic structures in 3-D and to develop some facility in interpreting the nature of geologic structures from geologic maps and geologic cross sections. A big part

Harbor, David

312

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

PubMed Central

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

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

2010-01-01

313

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.

314

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.

315

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.

316

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.

317

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.

318

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

319

Studies on the topology of the protein import channel in relation to the plant mitochondrial processing peptidase integrated into the cytochrome bc1 complex.  

PubMed

The mitochondrial processing peptidase (MPP) specifically cleaves N-terminal targeting signals from hundreds of nuclear-encoded, matrix-targeted precursor proteins. In contrast to yeast and mammals, the plant MPP is an integral component of the respiratory cytochrome bc1 complex. The topology of the protein import channel in relation to MPP/bc1 in plants was studied using chimeric precursors containing truncated cytochrome b2 (cyt b2) proteins of 55-167 residues in length, fused to dihydrofolate reductase (DHFR). The DHFR domain could be tightly folded by methotrexate (MTX), generating translocation intermediates trapped in the import channel with only the cyt b2 pre-sequence/mature domain protruding into the matrix. Spinach and soybean mitochondria imported and processed unfolded precursors. MTX-folded intermediates were not processed in spinach but the longest (1-167) MTX-folded cyt b2-DHFR construct was processed in soybean, while yeast mitochondria successfully processed even shorter MTX-folded constructs. The MTX-folded precursors were cleaved with high efficiency by purified spinach MPP/bc1 complex. We interpret these results as indicating that the protein import channel is located distantly from the MPP/bc1 complex in plants, and that there is no link between protein translocation and protein processing. PMID:11123802

Dessi, P; Rudhe, C; Glaser, E

2000-12-01

320

Airborne electromagnetic data and processing within Leach Lake Basin, Fort Irwin, California: Chapter G in Geology and geophysics applied to groundwater hydrology at Fort Irwin, California  

USGS Publications Warehouse

From December 2010 to January 2011, the U.S. Geological Survey conducted airborne electromagnetic and magnetic surveys of Leach Lake Basin within the National Training Center, Fort Irwin, California. These data were collected to characterize the subsurface and provide information needed to understand and manage groundwater resources within Fort Irwin. A resistivity stratigraphy was developed using ground-based time-domain electromagnetic soundings together with laboratory resistivity measurements on hand samples and borehole geophysical logs from nearby basins. This report releases data associated with the airborne surveys, as well as resistivity cross-sections and depth slices derived from inversion of the airborne electromagnetic data. The resulting resistivity models confirm and add to the geologic framework, constrain the hydrostratigraphy and the depth to basement, and reveal the distribution of faults and folds within the basin.

Bedrosian, Paul A.; Ball, Lyndsay B.; Bloss, Benjamin R.

2014-01-01

321

Zi-Wei Lin Oct 5, 2004 UAH / NASA Space Radiation Shielding Program, MS Determine Important Nuclear Fragmentation Processes  

E-print Network

Zi-Wei Lin Oct 5, 2004 UAH / NASA Space Radiation Shielding Program, MS Determine Important Nuclear? Conclusions Zi-Wei Lin University of Alabama in Huntsville/ NASA Space Radiation Shielding Program, MSFC #12;Zi-Wei Lin Oct 5, 2004 UAH / NASA Space Radiation Shielding Program, MS Cucinotta/JSC Individual

Lin, Zi-wei

322

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

Code of Federal Regulations, 2010 CFR

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

2010-01-01

323

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

Code of Federal Regulations, 2011 CFR

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

2011-01-01

324

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

Code of Federal Regulations, 2012 CFR

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

2012-01-01

325

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

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

2014-01-01

326

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

Code of Federal Regulations, 2013 CFR

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

2013-01-01

327

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 ModelsTeaching Project Team

2010-12-01

328

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

329

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

330

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

E-print Network

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

Florida, University of

331

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

Code of Federal Regulations, 2012 CFR

...exists or that present an undue risk of introducing BSE into the...subchapter as BSE minimal-risk regions, all steps of processing...region that presents an undue risk of introducing BSE into the...once per year), including travel, salary,...

2012-01-01

332

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

Code of Federal Regulations, 2011 CFR

...exists or that present an undue risk of introducing BSE into the...subchapter as BSE minimal-risk regions, all steps of processing...region that presents an undue risk of introducing BSE into the...once per year), including travel, salary,...

2011-01-01

333

THE IMPORTANCE OF RISK REDUCTION ON MERCHANT UPTAKE OF REAL-TIME CREDIT CARD PAYMENT PROCESSING SYSTEMS  

Microsoft Academic Search

Credit cards are the primary means of payment of goods and services over the Internet. Many characteristics of credit cards leave merchants vulnerable to fraud, inconvenience and loss of potential customers. Despite the fact that the security issues of confidentiality and integrity are largely addressed in real-time credit card payment processing systems (RTCCPS), the one missing link from a merchant's

Mustafa A. Ally

334

Spent coffee-based activated carbon: specific surface features and their importance for H2S separation process.  

PubMed

Activated carbons were prepared from spent ground coffee. Zinc chloride was used as an activation agent. The obtained materials were used as a media for separation of hydrogen sulfide from air at ambient conditions. The materials were characterized using adsorption of nitrogen, elemental analysis, SEM, FTIR, and thermal analysis. Surface features of the carbons depend on the amount of an activation agent used. Even though the residual inorganic matter takes part in the H(2)S retention via salt formation, the porous surface of carbons governs the separation process. The chemical activation method chosen resulted in formation of large volume of pores with sizes between 10 and 30?, optimal for water and hydrogen sulfide adsorption. Even though the activation process can be optimized/changed, the presence of nitrogen in the precursor (caffeine) is a significant asset of that specific organic waste. Nitrogen functional groups play a catalytic role in hydrogen sulfide oxidation. PMID:22154120

Kante, Karifala; Nieto-Delgado, Cesar; Rangel-Mendez, J Rene; Bandosz, Teresa J

2012-01-30

335

OneGeology-Europe - The Challenges and progress of implementing a basic geological infrastructure for Europe  

NASA Astrophysics Data System (ADS)

OneGeology-Europe is making geological spatial data held by the geological surveys of Europe more easily discoverable and accessible via the internet. This will provide a fundamental scientific layer to the European Plate Observation System Rich geological data assets exist in the geological survey of each individual EC Member State, but they are difficult to discover and are not interoperable. For those outside the geological surveys they are not easy to obtain, to understand or to use. Geological spatial data is essential to the prediction and mitigation of landslides, subsidence, earthquakes, flooding and pollution. These issues are global in nature and their profile has also been raised by the OneGeology global initiative for the International Year of Planet Earth 2008. Geology is also a key dataset in the EC INSPIRE Directive, where it is also fundamental to the themes of natural risk zones, energy and mineral resources. The OneGeology-Europe project is delivering a web-accessible, interoperable geological spatial dataset for the whole of Europe at the 1:1 million scale based on existing data held by the European geological surveys. Proof of concept will be applied to key areas at a higher resolution and some geological surveys will deliver their data at high resolution. An important role is developing a European specification for basic geological map data and making significant progress towards harmonising the dataset (an essential first step to addressing harmonisation at higher data resolutions). It is accelerating the development and deployment of a nascent international interchange standard for geological data - GeoSciML, which will enable the sharing and exchange of the data within and beyond the geological community within Europe and globally. The geological dataset for the whole of Europe is not a centralized database but a distributed system. Each geological survey implements and hosts an interoperable web service, delivering their national harmonized geological data. These datasets are registered in a multilingual catalogue, who is one the main part of this system. This catalogue and a common metadata profile allows the discovery of national geological and applied geological maps at all scapes, Such an architecture is facilitating re-use and addition of value by a wide spectrum of users in the public and private sector and identifying, documenting and disseminating strategies for the reduction of technical and business barriers to re-use. In identifying and raising awareness in the user and provider communities, it is moving geological knowledge closer to the end-user where it will have greater societal impact and ensure fuller exploitation of a key data resource gathered at huge public expense. The project is providing examples of best practice in the delivery of digital geological spatial data to users, e.g. in the insurance, property, engineering, planning, mineral resource and environmental sectors. The scientifically attributed map data of the project will provide a pan-European base for science research and, importantly, a prime geoscience dataset capable of integration with other data sets within and beyond the geoscience domain. This presentation will demonstrate the first results of this project and will indicate how OneGeology-Europe is ensuring that Europe may play a leading role in the development of a geoscience spatial data infrastructure (SDI) globally.

Asch, Kristine; Tellez-Arenas, Agnes

2010-05-01

336

Significant achievements in the planetary geology program. Final report  

Microsoft Academic Search

Developments reported at a meeting of principal investigators for NASA's planetology geology program are summarized. Topics covered include the following: 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

1978-01-01

337

Significant achievements in the planetary geology program, 1981  

NASA Technical Reports Server (NTRS)

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

Holt, H. E. (editor)

1981-01-01

338

Significant achievements in the Planetary Geology Program, 1981  

SciTech Connect

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

Holt, H.E.

1981-09-01

339

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.

340

Geologic mapping of northern Lunae Planun, Mars  

NASA Technical Reports Server (NTRS)

Lunae Planum is an elevated region east of the Tharsis rise, and ridged plains containing numerous Sacra Dorsa wrinkle ridges, cross-cutting Sacra Fossae grabens, and lobate scarps compose this Martian Plateau. Geologic mapping of the northern Lunae Planum region was undertaken to better understand to emplacement history of the ridge plains, the structural history of deformation, and the periods of fluvial processes that have modified the region. These investigations are important for several reasons: (1) the history of plains emplacement yields information valuable for understanding the evolution of Tharsis volcanism; (2) interpretation of structural deformation has implications on the lithology of the Martian crust; and (3) determining the history and fate of Martian volatiles is dependent upon knowing the periods of outflow activity. A discussion of the findings is presented.

Craddock, Robert A.; Maxwell, Ted A.

1991-01-01

341

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

PubMed

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

Tondeur, François; Cinelli, Giorgia; Dehandschutter, Boris

2014-10-01

342

A GFP endometriosis model reveals important morphological characteristics of the angiogenic process that govern benign and malignant diseases.  

PubMed

Endometriosis involves the growth of endometriotic tissue outside the uterine cavity, and is frequently associated with different malignancies. A well-reported alteration in the disease microenvironment is the proliferation of new blood vessels around the lesions, as part of a necessary repertory to contribute to the invasiveness and development of infiltrating endometriosis. Therefore, the establishment of a reliable experimental model is essential to elucidate the contribution of angiogenesis and to develop new therapeutic approaches to endometriosis treatment. For this purpose we transplanted endometrial fragments from green fluorescent protein (GFP)-mice (n=20) into the peritoneal cavity of wild-type mice (n=20), and then analyzed the morphological changes and the process of angiogenesis. The lesions were cystic and vascularized, and showed morphological hallmarks such as endometrial glands and stroma. An increase in endometriotic lesion vascular density was revealed by immunostaining and RNAm expression for Vegf and its receptor Flk-1, and the lesions were confirmed as a tissue-donor source by GFP fluorescent cells. The same pattern was observed through staining of activated macrophages and an increase of about 25% in the number of macrophage-positive cells was also demonstrated in endometriotic lesions by flow cytometry, which concords with previous data that correlate endometriosis, angiogenesis and inflammation. According to our understanding, this is the first demonstration that the pattern of the angiogenic process in the GFP endometriosis model is very similar to that of cancer. These observations will be useful for investigation of the process of angiogenesis involved in the attachment and invasion of endometrial cells, as well as an in vivo platform model to study the effects of antiangiogenic drugs. PMID:24385307

Machado, Daniel Escorsim; Palumbo, Antônio; Santos, João Marcos; Mattos, Rômulo Medina; dos Santos, Thiago Alves; Seabra, Sergio Henrique; Boldrini, Leonardo da Cunha; Perini, Jamila Alessandra; Nasciutti, Luiz Eurico

2014-07-01

343

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

344

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

345

Pennsylvania Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Pennsylvania Geological Survey. Users can access digital maps, data, and Geographic Information Systems (GIS), information on economic resources, and information on field mapping in the state. Classroom resources include a set of lesson plans on Pennsylvania geology; 'Rock Boxes', a set of rock samples which can be ordered; information on mineral collecting; and a series of educational publications, page-sized maps, and the 'Trail of Geology' park guide.

346

Icelandic Geology Resources  

NSDL National Science Digital Library

The main feature of this site from Hamrahlio College of Reykjavik, Iceland is an interactive geological map of Iceland showing lava flows and glaciers. Other highlights include links to related Icelandic geology pages (e.g., The Effect of Diatom Mining, Iceland's Ministry of the Environment), news sources and journals, and Icelandic geological societies (not all are in English). A recommended resource for glaciologists, volcanologists, and educators in earth science.

Douglas, Georg R.

347

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

348

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

E-print Network

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

Chatziantoniou, Damianos

349

Three important parts of an integrated plant are reactors, separators and a heat exchanger network (HEN) for heat recovery. Within the process engineering community, much  

E-print Network

exchanger network (HEN) for heat recovery. Within the process engineering community, much attention has beeni ABSTRACT Three important parts of an integrated plant are reactors, separators and a heat and in particular to optimal operation of HENs. The purpose of heat integration is to save energy, but the HEN also

Skogestad, Sigurd

350

Geologic Maps and Structures Name ______________________________ Geology 100 Harbor section  

E-print Network

Geologic Maps and Structures Name ______________________________ Geology 100 ­ Harbor section Read Ch. 7 before you begin. The objectives of this lab are for you to learn the basic geologic structures in 3-D and to develop some facility in interpreting the nature of geologic structures from geologic

Harbor, David

351

Environmental Geology Major www.geology.pitt.edu/uprogs.html  

E-print Network

Environmental Geology Major www.geology.pitt.edu/uprogs.html Revised: 04/2004 Environmental geology in environmental geology provides the diverse skills required to work in many different employment settings issues. Within the field of geology, environmental and geotechnical jobs exist for people with BS degrees

Jiang, Huiqiang

352

Department of Geology and Geological Engineering University of Mississippi Announces  

E-print Network

Department of Geology and Geological Engineering University of Mississippi Announces Krista Pursuing a degree within the Geology & Geological Engineering department Record of financial need the University of Mississippi with a Bachelor of Science degree in geological engineering in 1982. After earning

Elsherbeni, Atef Z.

353

Geologic Map of Mount Mazama and Crater Lake Caldera, Oregon  

USGS Publications Warehouse

Crater Lake partly fills one of the most spectacular calderas of the world, an 8-by-10-km basin more than 1 km deep formed by collapse of the volcano known as Mount Mazama (fig. 1) during a rapid series of explosive eruptions about 7,700 years ago. Having a maximum depth of 594 m, Crater Lake is the deepest lake in the United States. Crater Lake National Park, dedicated in 1902, encompasses 645 km2 of pristine forested and alpine terrain, including the lake itself, virtually all of Mount Mazama, and most of the area of the geologic map. The geology of the area was first described in detail by Diller and Patton (1902) and later by Williams (1942), whose vivid account led to international recognition of Crater Lake as the classic collapse caldera. Because of excellent preservation and access, Mount Mazama, Crater Lake caldera, and the deposits formed by the climactic eruption constitute a natural laboratory for study of volcanic and magmatic processes. For example, the climactic ejecta are renowned among volcanologists as evidence for systematic compositional zonation within a subterranean magma chamber. Mount Mazama's climactic eruption also is important as the source of the widespread Mazama ash, a useful Holocene stratigraphic marker throughout the Pacific Northwest, adjacent Canada, and offshore. A detailed bathymetric survey of the floor of Crater Lake in 2000 (Bacon and others, 2002) provides a unique record of postcaldera eruptions, the interplay between volcanism and filling of the lake, and sediment transport within this closed basin. Knowledge of the geology and eruptive history of the Mount Mazama edifice, greatly enhanced by the caldera wall exposures, gives exceptional insight into how large volcanoes of magmatic arcs grow and evolve. Lastly, the many smaller volcanoes of the High Cascades beyond the limits of Mount Mazama are a source of information on the flux of mantle-derived magma through the region. General principles of magmatic and eruptive processes revealed by the present study have been incorporated not only in scientific investigations elsewhere, but in the practical evaluation of hazards (Bacon and others, 1997b) and geothermal resources (Bacon and Nathenson, 1996) in the Crater Lake region. In addition to papers in scientific journals, field trip guides, and the hazard and geothermal reports, the major product of this long-term study of Mount Mazama is the geologic map. The map is unusual because it portrays bedrock (outcrop), surficial, and lake floor geology. Caldera wall geology is depicted in detail on the accompanying geologic panoramas.

Bacon, Charles R.

2008-01-01

354

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.

Andrew Smith

355

Modeling Geologic Time  

NSDL National Science Digital Library

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

Firebaugh, James

356

Arizona Geological Survey  

NSDL National Science Digital Library

This is the homepage of the Arizona Geological Survey. Information accessible here includes maps, information on oil, gas, and minerals in the state, back issues of the survey's newsletter, and a list of resources for public education in the state. These resources include information centers for Arizona geology and Earth Science, the survey's geology library and bibliographic database, a repository of rock cuttings and cores, and a contact for earth science education who will assist teacher groups in introducing local geology to their classes.

357

Dione's spectral and geological properties  

USGS Publications Warehouse

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

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

2010-01-01

358

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

359

Reports of Planetary Geology Program, 1981  

NASA Technical Reports Server (NTRS)

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

Holt, H. E. (compiler)

1981-01-01

360

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

361

The importance of sub-mesoscale processes for the exchange of properties through the Strait of Gibraltar  

NASA Astrophysics Data System (ADS)

This article presents a detailed analysis of the sub-mesoscale transport processes in the Strait of Gibraltar. The interest is focussed on the Camarinal Sill region, and special attention is paid to the across-strait transport processes, the divergences and convergences in the central zone, and the small-scale circulation patterns along the northern coastal margin. The analysis is based on high-resolution (7 m) SST images acquired by an air-borne hyper-spectral scanner, and has been complemented with a rhodamine-release experiment, continuous thermo-salinograph records, acoustic Doppler current (ADCP) profiles from both moorings and vessel-mounted experiments, and numerical modelling. It is deduced from the analysis that the coupling between the upwelling processes, induced by the internal tide and the generation of large-amplitude internal waves, and the cyclonic eddies formed on the coastal margin, seems to be the mechanism that explains the chlorophyll maxima frequently found on the coastal margin of the studied area. Further, as a consequence of the small-scale patterns of circulation induced by the internal waves, the suspended substances are displaced from the coastal margins toward the central zones and later are carried by the westward current toward the convergence zones created by the internal waves, where they may be retained and accumulate. Then, in the eastward phase of the tidal current over the Camarinal Sill, these nuclei of concentrated substances (nutrients, chlorophyll, and plankton) are transported toward the Alboran Sea, where they must contribute, in part, to the primary productivity there. High-resolution (7 m) SST images acquired by an Airborne Hyper-spectral Scanner (AHS) provided by the Spanish Institute of Aerospace Techniques (INTA). Measurements made along vessel transects crossing the studied zone, of current velocity and echo-intensity profiles acquired by ADCP, and sea surface temperature, salinity and released rhodamine (see Fig. 1). Several conductivity, temperature and depth (CTD) profiles taken at selected points within the region of the Camarinal Sill. Current velocity time-series recorded at two mooring placements within the studied zone (see Fig. 1). Numerical modelling of the tidal-induced hydro-dynamics. The most of the data used in the study have been collected during the oceanographic campaign “GIBRALTAR 2008” carried out onboard the R/V ‘Sarmiento de Gamboa’ during September and October 2008. The data used in this article were collected on September 17th 2008, in spring tides conditions, when the largest amplitude internal waves in Camarinal Sill are generated. As complementary information, we also make use of ADCP measurements taken onboard the R/V ‘García del Cid’ during a survey carried out in October 2004, and some satellite images of sea surface temperature and chlorophyll.

Bruno, M.; Chioua, J.; Romero, J.; Vázquez, A.; Macías, D.; Dastis, C.; Ramírez-Romero, E.; Echevarria, F.; Reyes, J.; García, C. M.

2013-09-01

362

Geologic investigations of outer planets satellites  

NASA Technical Reports Server (NTRS)

Four tests are examined: (1) investigation of volcanism on Io; Interim results of thermal and structural modeling of volcanism on Io are presented, (2) a study of the ancient heavily cratered regions on Ganymede, (3) a geologic comparison of the cratering record on Ganymede and Callisto, and (4) a geological and chemical investigation of internal resurfacing processes on the Saturnian satellites. Tasks 2, 3, and 4 utilize Voyager imaging data.

Strom, R. G.

1984-01-01

363

Mapping watershed potential to contribute phosphorus from geologic materials to receiving streams, southeastern United States  

USGS Publications Warehouse

As part of the southeastern United States SPARROW (SPAtially Referenced Regressions On Watershed attributes) water-quality model implementation, the U.S. Geological Survey created a dataset to characterize the contribution of phosphorus to streams from weathering and erosion of surficial geologic materials. SPARROW provides estimates of total nitrogen and phosphorus loads in surface waters from point and nonpoint sources. The characterization of the contribution of phosphorus from geologic materials is important to help separate the effects of natural or background sources of phosphorus from anthropogenic sources of phosphorus, such as municipal wastewater or agricultural practices. The potential of a watershed to contribute phosphorus from naturally occurring geologic materials to streams was characterized by using geochemical data from bed-sediment samples collected from first-order streams in relatively undisturbed watersheds as part of the multiyear U.S. Geological Survey National Geochemical Survey. The spatial pattern of bed-sediment phosphorus concentration is offered as a tool to represent the best available information at the regional scale. One issue may weaken the use of bed-sediment phosphorus concentration as a surrogate for the potential for geologic materials in the watershed to contribute to instream levels of phosphorus-an unknown part of the variability in bed-sediment phosphorus concentration may be due to the rates of net deposition and processing of phosphorus in the streambed rather than to variability in the potential of the watershed's geologic materials to contribute phosphorus to the stream. Two additional datasets were created to represent the potential of a watershed to contribute phosphorus from geologic materials disturbed by mining activities from active mines and

Terziotti, Silvia; Hoos, Anne B.; Harned, Douglas; Garcia, Ana Maria

2010-01-01

364

Virtual Sources in OMCVD Growth of ZnO: The importance of real-time diagnostics for process development  

NASA Astrophysics Data System (ADS)

Growth of zinc oxide (ZnO) by organometallic chemical vapor deposition (OMCVD) is of high current interest because ZnO is nominally a plentiful, low-cost replacement for nitride devices, which rely on Ga. and In, and because CVD is a scalable process. However the extreme reactivity of the common zinc precursor, diethylzinc (DEZ), and the high volatility of ZnO itself make growth via CVD a challenging balance between deposition and sublimation. Using an OMCVD reactor with an integrated spectroscopic polarimeter, we have investigated growth of ZnO on sapphire in real time and have identified 3 factors that must be managed for successful growth. First, the immediate reaction of DEZ with the oxidizer species forms particles of ZnO and/or ZnO adducts, which we term the virtual source. These particles are large enough to scatter light, although the scatter vanishes at a well-defined distance above the growth surface as a result of particle size being reduced below the scattering threshold by sublimation. Second, a seed layer is necessary for growth to begin. Third, the volatility of ZnO at growth temperatures results in large exchange currents between the virtual source and the deposited material such that deposition is essentially reversible. A sequence of real-time spectra illustrates the formation of a seed layer, subsequent growth, and removal of deposited material by sublimation.

Adles, E. J.; Liu, X.; Aspnes, D. E.

2008-10-01

365

Sample Preparation for Determination of Rare Earth Elements in Geological Samples by ICP-MS: A Critical Review  

Microsoft Academic Search

The presence of rare earth elements (REE) in geological materials provides important information about the formation and the geochemical processes suffered by the rocks. Therefore, there is a constant necessity for accurate data and reliable and fast analytical methods. However, the low concentrations of these elements typically found in rocks require quantification by sufficiently sensitive techniques, such as Inductively Coupled

Frederico Garcia Pinto; Rainério Escalfoni Junior; Tatiana Dillenburg SaintPierre

2012-01-01

366

Geologic Time Online Edition  

NSDL National Science Digital Library

This tutorial will help students learn and understand the concepts of geologic time and the age of the Earth. They will investigate the geologic time scale and learn about the use of index fossils and radiometric dating to determine the age of rock formations and fossils.

367

Geologic time scale bookmark  

USGS Publications Warehouse

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

U.S. Geological Survey

2012-01-01

368

Paleogeography Through Geologic Time  

NSDL National Science Digital Library

This website contains paleogeographic and plate tectonic reconstructions organized by geologic period. Users select a geologic period, and receive a summary of the major events that occurred during that period, a paleogeographic map, tectonics and sedimentation of the North Atlantic region, and global tectonic features from that time.

Blakey, Ronald

369

Geological Map Problem  

NSDL National Science Digital Library

This is a lab activity that is designed to help introductory, non-science majors integrate their geological knowledge near the end of the course. In this activity, students work in self-selected groups of up to four per group on the history of a sketch geological map.

Robert Filson

370

People and Geology.  

ERIC Educational Resources Information Center

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

Naturescope, 1987

1987-01-01

371

Glossary of geology  

SciTech Connect

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

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

1987-01-01

372

Advances in Planetary Geology  

NASA Technical Reports Server (NTRS)

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

Woronow, A. (editor)

1982-01-01

373

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.

374

BS in GEOLOGY: Environmental Geology Emphasis (694029) MAP Sheet Department of Geological Sciences  

E-print Network

BS in GEOLOGY: Environmental Geology Emphasis (694029) MAP Sheet Department of Geological Sciences with environmental degradation and natural geologic hazards has led to a demand for geologists who are both well grounded in the fundamentals of the science of geology and specifically prepared to address environmental

Seamons, Kent E.

375

British Geological Survey: Learning  

NSDL National Science Digital Library

The British Geological Survey (BGS) has a wealth of information about the earth sciences, and they are quite willing to share it with others. This page contains information and resources for anyone interested in geology for educational or leisure purposes, and it is contained with four sections. First up is "Popular geology", which includes "Britain beneath our feet", an interactive atlas of geology, resources, and land quality. This section also contains graphics about climate change and earthquakes. The second section is titled "Educational resources". Here visitors can ask scientists at the BGS specific questions and they can also download several free posters. The third section is called "Educational news and events" and it features upcoming events at the BGS and links to their free magazine, "Earthwise". The site is rounded out by the fourth section titled "From the BGS Archives". Here visitors can view historic geological photographs and also view field sketches and watercolors by Alexander Henry Green, the celebrated Victorian geologist.

376

Wyoming State Geological Survey  

NSDL National Science Digital Library

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

377

FtsH-dependent Processing of RNase Colicins D and E3 Means That Only the Cytotoxic Domains Are Imported into the Cytoplasm*  

PubMed Central

It has long been suggested that the import of nuclease colicins requires protein processing; however it had never been formally demonstrated. Here we show that two RNase colicins, E3 and D, which appropriate two different translocation machineries to cross the outer membrane (BtuB/Tol and FepA/TonB, respectively), undergo a processing step inside the cell that is essential to their killing action. We have detected the presence of the C-terminal catalytic domains of these colicins in the cytoplasm of target bacteria. The same processed forms were identified in both colicin-sensitive cells and in cells immune to colicin because of the expression of the cognate immunity protein. We demonstrate that the inner membrane protease FtsH is necessary for the processing of colicins D and E3 during their import. We also show that the signal peptidase LepB interacts directly with the central domain of colicin D in vitro and that it is a specific but not a catalytic requirement for in vivo processing of colicin D. The interaction of colicin D with LepB may ensure a stable association with the inner membrane that in turn allows the colicin recognition by FtsH. We have also shown that the outer membrane protease OmpT is responsible for alternative and distinct endoproteolytic cleavages of colicins D and E3 in vitro, presumably reflecting its known role in the bacterial defense against antimicrobial peptides. Even though the OmpT-catalyzed in vitro cleavage also liberates the catalytic domain from colicins D and E3, it is not involved in the processing of nuclease colicins during their import into the cytoplasm. PMID:21700705

Chauleau, Mathieu; Mora, Liliana; Serba, Justyna; de Zamaroczy, Miklos

2011-01-01

378

77 FR 19032 - Geological Survey  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF THE INTERIOR Geological Survey Announcement of National Geospatial...Advisory Committee Meeting AGENCY: U.S. Geological Survey, Interior. ACTION: Notice...contacting Arista Maher at the U.S. Geological Survey (703-648-6283,...

2012-03-29

379

Essential Elements of Geologic Reports.  

ERIC Educational Resources Information Center

Described is a report outline for geologic reports. Essential elements include title; abstract; introduction; stratigraphy; petrography; geochemistry; petrology; geophysics; structural geology; geologic history; modeling; economics; conclusions; and recommendations. (Author/CW)

Webb, Elmer James

1988-01-01

380

Principles of Historical Geology Geology 331  

E-print Network

in Biostratigraphy Section #12;Principle of Superposition In any undeformed sequence of sedimentary rocks, each bed of a valley can be correlated. · This principle is used to trace coal seams from one mountain to the next;Igneous dikes in black, granite in pink #12;#12;Can you interpret the sequence of geologic events using

Kammer, Thomas

381

Geologic effects on groundwater salinity and discharge into an estuary  

USGS Publications Warehouse

Submarine groundwater discharge (SGD) can be an important pathway for transport of nutrients and contaminants to estuaries. A better understanding of the geologic and hydrologic controls on these fluxes is critical for their estimation and management. We examined geologic features, porewater salinity, and SGD rates and patterns at an estuarine study site. Seismic data showed the existence of paleovalleys infilled with estuarine mud and peat that extend hundreds of meters offshore. A low-salinity groundwater plume beneath this low-permeability fill was mapped with continuous resistivity profiling. Extensive direct SGD measurements with seepage meters (n = 551) showed fresh groundwater discharge patterns that correlated well with shallow porewater salinity and the hydrogeophysical framework. Small-scale variability in fresh and saline discharge indicates influence of meter-scale geologic heterogeneity, while site-scale discharge patterns are evidence of the influence of the paleovalley feature. Beneath the paleovalley fill, fresh groundwater flows offshore and mixes with saltwater before discharging along paleovalley flanks. On the adjacent drowned interfluve where low-permeability fill is absent, fresh groundwater discharge is focused at the shoreline. Shallow saltwater exchange was greatest across sandy sediments and where fresh SGD was low. The geologic control of groundwater flowpaths and discharge salinity demonstrated in this work are likely to affect geochemical reactions and the chemical loads delivered by SGD to coastal surface waters. Because similar processes are likely to exist in other estuaries where drowned paleovalleys commonly cross modern shorelines, the existence and implications of complex hydrogeology are important considerations for studies of groundwater fluxes and related management decisions.

Russonielloa, Christopher J.; Fernandeza, Cristina; Brattonb, John F.; Banaszakc, Joel F.; Krantzc, David E.; Andresd, Scott; Konikowe, Leonard F.; Michaela, Holly A.

2013-01-01

382

What is Geologic Time?  

NSDL National Science Digital Library

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

383

Formation evaluation: Geological procedures  

SciTech Connect

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

Whittaker, A.

1985-01-01

384

Journal of Geology  

NSDL National Science Digital Library

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

385

Nordic geoscience and the 3rd international geological congress: Introduction  

Microsoft Academic Search

Geology has been of profound importance for the Nordic countries since\\u000a the Middle Ages. Strong economies were built on an understanding of the\\u000a occurrence in bedrock of minerals containing metals, e.g., silver,\\u000a copper, zinc and iron, and eventually led to the establishment of the\\u000a first Geological Surveys in Norway and Sweden in the middle of the\\u000a nineteenth century. The geology

David G. Gee; Harald Brekke; Raimo Lahtinen; Freysteinn Sigmundsson; Bjoern Sundquist; Hans Thybo; Paer Weihed

2008-01-01

386

Geology before Pluto: Pre-encounter considerations  

NASA Astrophysics Data System (ADS)

The cameras of New Horizons will provide robust data sets that should be imminently amenable to geological analysis of the Pluto system's landscapes. In this paper, we begin with a brief discussion of the planned observations by the New Horizons cameras that will bear most directly on geological interpretability. Then we broadly review the major geological processes that could potentially operate on the surfaces of Pluto and its major moon Charon. We 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. We conclude with an assessment of the prospects for endogenic activity in the form of tectonics and cryovolcanism.

Moore, Jeffrey M.; Howard, Alan D.; Schenk, Paul M.; McKinnon, William B.; Pappalardo, Robert T.; Ewing, Ryan C.; Bierhaus, Edward B.; Bray, Veronica J.; Spencer, John R.; Binzel, Richard P.; Buratti, Bonnie; Grundy, William M.; Olkin, Catherine B.; Reitsema, Harold J.; Reuter, Dennis C.; Stern, S. Alan; Weaver, Harold; Young, Leslie A.; Beyer, Ross A.

2015-01-01

387

Geological research for public outreach and education in Lithuania  

NASA Astrophysics Data System (ADS)

Successful IYPE activities and implementation of Geoheritage day in Lithuania increased public awareness in geology. A series of projects introducing geology to the general public and youth, supported by EU funds and local communities, were initiated. Researchers from the scientific and applied geology institutions of Lithuania participated in these projects and provided with the geological data. In one case, the Lithuanian Survey of Protected Areas supported the installation of a series of geological exhibitions in several regional and national parks. An animation demonstrating glacial processes was chosen for most of these because the Lithuanian surface is largely covered with sedimentary deposits of the Nemunas (Weichselian) glaciation. Researchers from the Lithuanian Geological Survey used the mapping results to demonstrate real glacial processes for every chosen area. In another case, 3D models showing underground structures of different localities were based on detailed geological maps and profiles obtained for that area. In case of the Sartai regional park, the results of previous geological research projects provided the possibility to create a movie depicting the ca. 2 Ga geological evolution of the region. The movie starts with the accretion of volcanic island arcs on the earlier continental margin at ca. 2 Ga and deciphers later Precambrian tectonic and magmatic events. The reconstruction is based on numerous scientific articles and interpretation of geophysical data. Later Paleozoic activities and following erosion sculptured the surface which was covered with several ice sheets in Quaternary. For educational purpose, a collection of minerals and rocks at the Forestry Institute was used to create an exhibition called "Cycle of geological processes". Forestry scientists and their students are able to study the interactions of geodiversity and biodiversity and to understand ancient and modern geological processes leading to a soil formation. An aging exposition at the Museum of Erratic Boulders in NW Lithuania is being rearranged for educational purposes, to show the major rock types and their origins more clearly. A new exhibition is supplemented with computer portals presenting geological processes, geological quizzes, animations etc. Magmatism, metamorphism, sedimentation and other geological processes are demonstrated using erratic boulders brought by glaciers from Scandinavia and northern Russia. A part of the exhibition is devoted to glaciation processes and arrival of ice sheets to Lithuania. Visitors are able to examine large erratic boulder groups in a surrounding park and to enjoy beautiful environment. The exhibition also demonstrates mineral resources of Lithuania, different fossils and stones from a human body. In all cases it was recognised that a lack of geological information limits the use of geology for public outreach. Ongoing scientific research is essential in many places as well as a mediator's job for interpreting the results of highly specialised research results and to adapt them for public consumption.

Skridlaite, Grazina; Guobyte, Rimante

2013-04-01

388

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

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

389

Web Geologic Time Scale  

NSDL National Science Digital Library

The University of California-Berkeley Museum of Paleontology (last mentioned in the June 16, 1995 Scout Report) has recently updated its Web Geologic Time Scale, an online feature that helps users learn about the geologic timeline and explore related museum exhibits. The familiar geologic timeline appears on the main page of the Web site, with hypertext links for each division of time. Every page of the Web Geologic Time Machine site is liberally sprinkled with links to related UCMP Web pages; think of it as a portal to all online information available from the museum. Altogether, this Web site provides a well-organized and comprehensive resource for learning how the planet has changed over time, and would be a great addition to earth or life sciences classroom material for a broad range of grades.

1994-01-01

390

Interactive Geologic Timeline Activity  

NSDL National Science Digital Library

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

University, Environmental L.

391

Scaling the Geologic Past  

ERIC Educational Resources Information Center

Describes construction of a Geologic Time Scale on a 100 foot roll of paper and suggests activities concerning its use. Includes information about fossils and suggestions for conducting a fossil field trip with students. (BR)

Gerritts, Mary

1975-01-01

392

Comprehending Geologic Time  

NSDL National Science Digital Library

This online calculator helps students understand the classic analogy of relating the geologic time scale to a yard stick. It will help reinforce the concept of the briefness of human history relative to the age of the Earth.

393

North Dakota Geological Survey  

NSDL National Science Digital Library

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

394

Economic Geology (Oil & Gas)  

ERIC Educational Resources Information Center

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

Geotimes, 1972

1972-01-01

395

Photos of structural geology  

NSDL National Science Digital Library

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

Miller, Marli

396

Reconstructing the Geologic Timeline.  

ERIC Educational Resources Information Center

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

Hemler, Deb; Repine, Tom

2002-01-01

397

Bedrock Geology Mapping Exercise  

NSDL National Science Digital Library

This field mapping and map-making exercise is a capstone project for a course on Geological Maps. Over a weekend (~12 hours of field work), students collect lithologic and structural data from outcrops scattered over a one square mile area. Back in the classroom, students digitally compile their field data (outcrop, structure measurements, traverse locations) into ArcMAP. They infer geologic linework (faults and contacts) and units from this data in ArcMAP and then export these data layers into Illustrator. In Illustrator, they add ancillary map components (a cross section, description of map units, correlation diagram, map symbol legend,...) to create a final map at a 1:10,000 scale. Their maps are printed out on 11"x17" paper and saved as a pdf file. This exercise helps the students to appreciate how field data is collected and how these geologic facts are interpretively organized into a four-dimensional picture that is a geologic map.

Miller, Jim

398

USGS Geologic Hazards  

NSDL National Science Digital Library

The Geologic Hazards section of the US Geological Survey (USGS) conducts research into the causes of geological phenomena such as landslides and earthquakes. The homepage connects visitors to the Geologic Hazards team's three main areas of endeavor. Geomagnetism provides links to the National Geomagnetic Information Center; Magnetic Observatories, Models, and Charts; and the Geomagnetic Information Node, which receives geomagnetic observatory data from around the world. The Landslide group studies the "causes and mechanisms of ground failure" to prevent "long-term losses and casualties." Their section provides links to the program and information center, publications, events, and current projects. The Earthquakes department hosts a wealth of information, including neotectonics, engineering seismology, and paleoseismology. Interactive maps are also provided.

399

Geologic exploration of Mars  

NASA Technical Reports Server (NTRS)

The scientific objectives and methods involved in a geologic exploration of Mars from a manned outpost are discussed. The constraints on outpost activities imposed by the limited crew size, limited amount of time available for science, the limited diversity of scientific expertise, and the competition between scientific disciplines are addressed. Three examples of possible outpost locations are examined: the Olympus Mons aureole, Mangala Valles/Daedalia Planum, and Candor Chasma. The geologic work that could be done at each site is pointed out.

Plescia, J. B.

1990-01-01

400

Understanding Geologic Time  

NSDL National Science Digital Library

This informational tour offers students a basic understanding of geologic time, the evidence for events in the history of the Earth, relative and absolute dating techniques, and the significance of the Geologic Time Scale. Students move at a self-selected pace by answering questions correctly as they go. The teacher's guide contains all the details needed to use this computer activity, including handouts, a lesson plan, and assessment materials.

Scotchmoor, Judy

401

Geologic Time Discussion Analogies  

NSDL National Science Digital Library

The slides provide a fun way of discussing the immensity of geologic time and help to grasp the age of the earth, the time gaps between major geologic events, and the relative minuteness of humans time on earth. After the discussion with the class, students are given opportunity to develop their own analogies using "everyday" things (other than the calendar and money examples used in this activity).

Noah Fay

402

Johnston Geology Museum  

NSDL National Science Digital Library

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

2011-07-07

403

Oahu Geology Field Exercises  

NSDL National Science Digital Library

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

404

Interpreting Geologic Sections  

NSDL National Science Digital Library

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

Paul Morris

405

Geology and Human Health  

NSDL National Science Digital Library

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

406

OneGeology - Access to geoscience for all  

NASA Astrophysics Data System (ADS)

OneGeology is an initiative of Geological Survey Organisations (GSO) around the globe that dates back to Brighton, UK in 2007. Since then OneGeology has been a leader in developing geological online map data using a new international standard - a geological exchange language known as 'GeoSciML'. Increased use of this new language allows geological data to be shared and integrated across the planet with other organisations. One of very important goals of OneGeology was a transfer of valuable know-how to the developing world, hence shortening the digital learning curve. In autumn 2013 OneGeology was transformed into a Consortium with a clearly defined governance structure, making its structure more official, its operability more flexible and its membership more open where in addition to GSO also to other type of organisations that manage geoscientific data can join and contribute. The next stage of the OneGeology initiative will hence be focused into increasing the openness and richness of that data from individual countries to create a multi-thematic global geological data resource on the rocks beneath our feet. Authoritative information on hazards and minerals will help to prevent natural disasters, explore for resources (water, minerals and energy) and identify risks to human health on a planetary scale. With this new stage also renewed OneGeology objectives were defined and these are 1) to be the provider of geoscience data globally, 2) to ensure exchange of know-how and skills so all can participate, and 3) to use the global profile of 1G to increase awareness of the geosciences and their relevance among professional and general public. We live in a digital world that enables prompt access to vast amounts of open access data. Understanding our world, the geology beneath our feet and environmental challenges related to geology calls for accessibility of geoscientific data and OneGeology Portal (portal.onegeology.org) is the place to find them.

Komac, Marko; Lee, Kathryn; Robida, Francois

2014-05-01

407

Paleontology at the US Geological Survey  

NSDL National Science Digital Library

"Paleontology, the science which uses fossils to study life in past geologic time, has served an important role in geologic studies at the USGS since its establishment in 1879." The Paleontology at the US Geological Survey Web site contains a broad introduction to the subject and provides links to various products produced by the agency. The Fossil Groups link lets visitors learn about the different types of fossils, how they lived, and how they are used to answer important questions about the world we inhabit, including well written descriptions and many photographs. A products link offers a large list of paleontological publications. The educational resources page rounds out the informative and interesting site, giving anyone interested something to enjoy. [JAB

408

Quaternary Geologic Map of Connecticut and Long Island Sound Basin  

USGS Publications Warehouse

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

Stone, Janet Radway; Schafer, John P.; London, Elizabeth Haley; DiGiacomo-Cohen, Mary L.; Lewis, Ralph S.; Thompson, Woodrow B.

2005-01-01

409

Illustrated Glossary of Geologic Terms  

NSDL National Science Digital Library

Provided by the Geology Department at Iowa State University, this handy illustrated glossary of geological terms is an excellent quick reference resource for students. Continuously upgraded with links to illustrations and text, this geological lexicon is based on the glossary in the textbook Earth: An Introduction to Geological Change by S. Judson and S.M. Richardson. Alphabetical tabs and internal links to related terms let users move quickly around this useful aid for geology students.

410

Connecting Soils and Glacial Geology  

NSDL National Science Digital Library

The goal of this activity is to provide students an opportunity to connect soil science to surficial geology by using a Soil Surveys. By the end of the activity, students should be able to use a Soil Survey to identify and interpret landforms and surficial features. This activity can be adapted to variety of process (ex. eolian deposits, glacial deposits, bedrock weathering, etc.). County-level soil surveys are available in both paper and online formats for the majority of the United States. Designed for a geomorphology course Has minimal/no quantitative component

Holly Dolliver

411

A Lithology Based Map Unit Schema For Onegeology Regional Geologic Map Integration  

NASA Astrophysics Data System (ADS)

A system of lithogenetic categories for a global lithological map (GLiM, http://www.ifbm.zmaw.de/index.php?id=6460&L=3) has been compiled based on analysis of lithology/genesis categories for regional geologic maps for the entire globe. The scheme is presented for discussion and comment. Analysis of units on a variety of regional geologic maps indicates that units are defined based on assemblages of rock types, as well as their genetic type. In this compilation of continental geology, outcropping surface materials are dominantly sediment/sedimentary rock; major subdivisions of the sedimentary category include clastic sediment, carbonate sedimentary rocks, clastic sedimentary rocks, mixed carbonate and clastic sedimentary rock, colluvium and residuum. Significant areas of mixed igneous and metamorphic rock are also present. A system of global categories to characterize the lithology of regional geologic units is important for Earth System models of matter fluxes to soils, ecosystems, rivers and oceans, and for regional analysis of Earth surface processes at global scale. Because different applications of the classification scheme will focus on different lithologic constituents in mixed units, an ontology-type representation of the scheme that assigns properties to the units in an analyzable manner will be pursued. The OneGeology project is promoting deployment of geologic map services at million scale for all nations. Although initial efforts are commonly simple scanned map WMS services, the intention is to move towards data-based map services that categorize map units with standard vocabularies to allow use of a common map legend for better visual integration of the maps (e.g. see OneGeology Europe, http://onegeology-europe.brgm.fr/ geoportal/ viewer.jsp). Current categorization of regional units with a single lithology from the CGI SimpleLithology (http://resource.geosciml.org/201202/ Vocab2012html/ SimpleLithology201012.html) vocabulary poorly captures the lithologic character of such units in a meaningful way. A lithogenetic unit category scheme accessible as a GeoSciML-portrayal-based OGC Styled Layer Description resource is key to enabling OneGeology (http://oneGeology.org) geologic map services to achieve a high degree of visual harmonization.

Moosdorf, N.; Richard, S. M.

2012-12-01

412

Strain and texture measurements on geological samples using neutron diffraction at IBR2, Joint Institute for Nuclear Research, Dubna (Russia)  

Microsoft Academic Search

Information on texture and residual stress in geological samples is very important for the calculation of physical properties\\u000a connected with the evaluation of the geomechanical behavior of parts of the earths’s crust in connection with processes from\\u000a human activities (mining, tunnelling) and natural processes of deformation (seismicity, earthquakes). Texture and stress are\\u000a not independent of each other and in the

A. Frischbutter; Ch. Janssen; Ch. Scheffzük; K. Walther; K. Ullemeyer; J. H. Behrmann; A. N. Nikitin; T. I. Ivankina; H. Kern; B. Leiss

2006-01-01

413

The Evolution of Dinosaurs Over Geologic Time  

NSDL National Science Digital Library

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

414

Geology Fieldnotes: Glacier National Park, Montana  

NSDL National Science Digital Library

Glaciers have played an important role in shaping this park, which is part of the Rocky Mountain chain and shares a border with Canada's Waterton Lakes National Park. Information on this site includes park geology, visitor information, photographs, and links to other resources.

415

OneGeology-Europe Plus Initiative  

NASA Astrophysics Data System (ADS)

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

Capova, Dana; Kondrova, Lucie

2014-05-01

416

The geologic mapping of asteroid Vesta  

NASA Astrophysics Data System (ADS)

As part of NASA's Dawn mission [1,2] we conducted a geologic mapping campaign to provide a systematic, cartography-based initial characterization of the global and regional geology of asteroid Vesta. The goal of geological maps is to place observations of surface features into their stratigraphic context to develop a geologic history of the evolution of planetary surfaces. Geologic mapping reduces the complexity of heterogeneous planetary surfaces into comprehensible portions, defining and characterizing discrete material units based upon physical attributes related to the geologic processes that produced them, and enabling identification of the relative roles of various processes (impact cratering, tectonism, volcanism, erosion and deposition) in shaping planetary surfaces [3,4]. The Dawn Science Team produced cartographic products of Vesta from the Framing Camera images, including global mosaics as well as 15 regional quadrangles [5], which served as bases for the mapping. We oversaw the geologic mapping campaign during the Nominal Mission, including production of a global geologic map at scale 1:500,000 using images from the High Altitude Mapping Orbit [6] and 15 quadrangle geologic maps at scale 1:250,000 using images from the Low Altitude Mapping Orbit [7]. The goal was to support the Dawn Team by providing geologic and stratigraphic context of surface features and supporting the analysis of data from the Visible and Infrared Spectrometer (VIR) and the Gamma Ray and Neutron Detector (GRaND). Mapping was done using ArcGIS™ software, in which quadrangle mapping built on interpretations derived from the global geologic map but were updated and modified to take advantage of the highest spatial resolution data. Despite challenges (e.g., Vesta's highly sloped surface [8] deforms impact craters and produces mass movements that buries contacts), we were successfully able to map the whole surface of Vesta and identify a geologic history as represented in our maps and the resulting time-stratigraphic system and geologic timescale. Key results from the geologic mapping of Vesta include: 1) surface units are dominated by features and materials produced by two major impact events, the older Veneneia and younger Rheasilvia impacts at the south pole 2) both impacts produced a ridge-and-trough terrain as a tectonic response to the impacts, mapped as the Saturnalia Fossae and the Divalia Fossae Formations, respectively 3) stratigraphic analysis of Vesta's heavily cratered terrains show that portions of the original crust are preserved and predate the Veneneia impact 4) the Marcia impact event marks the beginning of Vesta's final stratigraphic period, including exposure of fresh bright and dark material and preservation of young bright-rayed and dark-rayed craters. We conclude that a geologic mapping campaign, including both global and regional mapping, can be conducted during the limited planetary nominal mission timeline, and is an excellent way to engage younger team members (graduate students and postdocs) in mission data analysis activities.

Williams, D.; Yingst, A.; Garry, B.

2014-07-01

417

Minnesota Geological Survey  

NSDL National Science Digital Library

The Minnesota Geological Survey (MGS) was established in 1872 as part of the University of Minnesota. The function of the MGS is to serve "the people of Minnesota by providing systematic geoscience information to support stewardship of water, land, and mineral resources." This website from the Digital Conservancy at the University of Minnesota provides access to all of items published by the MGS. The items are contained within the Collections area, and visitors will find headings here such as "Geology of Minnesota Parks," "County Atlas Series," and the "Bulletin of the Minnesota Geological and Natural History Survey." First-time visitors can check out the Recent Submissions area on the right-hand side of the page to look over some new findings, including hydrogeological maps of different counties around the state. One item that should not be missed is the "Geology of Minnesota: A Centennial Volume" from 1972. It's a tremendous volume and one that cannot be ignored by students of the physical landscape and geological history of the state.

2012-09-21

418

Geological and mathematical framework for failure modes in granular rock  

E-print Network

Geological and mathematical framework for failure modes in granular rock Atilla Aydina, *, Ronaldo processes in granular rock and provide a geological framework for the corresponding structures. We describe show that sharp structures overlap older narrow tabular structures in the same rock. This switch

Borja, Ronaldo I.

419

Cognitive Factors Affecting Student Understanding of Geologic Time.  

ERIC Educational Resources Information Center

Presents a model that describes how students reconstruct geological transformations over time. Defines the critical factors influencing reconstructive thinking: (1) the transformation scheme, which influences the other diachronic schemes; (2) knowledge of geological processes; and (3) extracognitive factors. (Author/KHR)

Dodick, Jeff; Orion, Nir

2003-01-01

420

Activities in planetary geology for the physical and earth sciences  

NASA Technical Reports Server (NTRS)

A users guide for teaching activities in planetary geology, and for physical and earth sciences is presented. The following topics are discussed: cratering; aeolian processes; planetary atmospheres, in particular the Coriolis Effect and storm systems; photogeologic mapping of other planets, Moon provinces and stratigraphy, planets in stereo, land form mapping of Moon, Mercury and Mars, and geologic features of Mars.

Dalli, R.; Greeley, R.

1982-01-01

421

Geodynamics applications of continuum physics to geological problems  

Microsoft Academic Search

This textbook deals with the fundamental physical processes necessary for an understanding of plate tectonics and a variety of geologic phenomena. The first chapter reviews plate tectonics; its main purpose is to provide physics, chemistry, and engineering students with the geologic background necessary to understand the applications throughout the rest of the book. It goes on to discuss in following

D. L. Turcotte; G. Schubert

1982-01-01

422

Infrequent earthquakes and far-field plate tectonic forces: the importance of crustal structure in relating short and long term processes in intraplate settings.  

NASA Astrophysics Data System (ADS)

Regions of the Earth located far from active plate boundaries are subject to subtle, yet very significant tectonic stresses which propagate large distances from active plate boundaries. Intraplate earthquakes release the accumulated strain in infrequent events, often at unforeseen locations. We examine the interplay between the short term and long term processes using the distribution and focal mechanisms of earthquakes from regions of the Antarctic and Australian continents. Providing a coherent explanation of such processes requires an understanding of the long term current and recent plate dynamics, also incorporating relict structures and deformation from past plate interactions. Short term processes, in particular the infrequent earthquakes characteristic of intraplate regions are important clues to pervasive stress directions, but can also be misleading. We provide examples of the reinterpretation of an earthquake focal mechanism that was made possible by improving the detailed structure of the source and surrounding area. Such examples show that the response to intraplate stress and strain, in the far-field plate tectonic environment, can be highly variable. Crustal structure is therefore significant on two accounts. It produces heterogeneities in strain accommodation, and stress propagation, resulting in significant local variations in stress magnitude and direction. Structure is also an essential component in the correct determination of the earthquake focal mechanisms from infrequent events which help to constrain the orientations of crustal stress and strain across extensive areas of the Earth.

Reading, A. M.; Young, M. K.; Rawlinson, N.; Tkalcic, H.; Sandiford, M.

2012-12-01

423

Minnesota Geological Survey  

NSDL National Science Digital Library

Established in 1872 by the State of Minnesota as part of the University of Minnesota, the Minnesota Geological Survey (MGS) serves the people of Minnesota by providing systematic geoscience information to support the stewardship of water, land, and mineral resources. This rather lovely digital collection brings together a record of all items published by the MGS since its creation. Here, visitors will find documents, reports, maps, and GIS data for online viewing or downloading as well. The thematic collections here include the Aeromagnetic Map Series, the annual reports of the Minnesota Geological and Natural History Survey, and the wonderful county atlas series. Visitors with a penchant for geology, natural history, and geography will find much to enjoy here.

424

Geologic map of Mars  

USGS Publications Warehouse

This global geologic map of Mars, which records the distribution of geologic units and landforms on the planet's surface through time, is based on unprecedented variety, quality, and quantity of remotely sensed data acquired since the Viking Orbiters. These data have provided morphologic, topographic, spectral, thermophysical, radar sounding, and other observations for integration, analysis, and interpretation in support of geologic mapping. In particular, the precise topographic mapping now available has enabled consistent morphologic portrayal of the surface for global mapping (whereas previously used visual-range image bases were less effective, because they combined morphologic and albedo information and, locally, atmospheric haze). Also, thermal infrared image bases used for this map tended to be less affected by atmospheric haze and thus are reliable for analysis of surface morphology and texture at even higher resolution than the topographic products.

Tanaka, Kenneth L.; Skinner, James A.; Dohm, James M.; Irwin, Rossman P., III; Kolb, Eric J.; Fortezzo, Corey M.; Platz, Thomas; Michael, Gregory G.; Hare, Trent M.

2014-01-01

425

Sedimentology and petroleum geology  

SciTech Connect

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

Bjorlykke, K.

1989-01-01

426

Global sedimentary geology program  

SciTech Connect

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

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

1986-07-01

427

Geology of Io  

NASA Technical Reports Server (NTRS)

Geologic mapping of the Jovian satellite Io has been completed at 1:15,000,000 scale for an area lying between +40 and -90 deg latitude and 230 and 45 deg longitude, which includes portions of the Ruwa Patera quadrangle (Ji2) and the Lerna Region (Ji4) and the westernmost section of the Colchis Region (Ji3). Image resolution in the mapped area is commonly 0.5 to 2 km/pxl. High resolution areas (less than .5 km/pxl) are located near the south pole (Lerna Region) and in eastern Ruwa Patera quadrangle. Geologic maps for the Ruwa Patera quadrangle (Ji2) and the Lerna Region (Ji4) have been produced at 1:5,000,000 scale. The present effort reexamines the previously mapped areas and synthesizes the geology of Io on a global scale.

Greeley, R.; Craddock, R. A.; Crown, D. A.; Leshin, L. A.; Schaber, G. G.

1987-01-01

428

Principles of isotope geology  

Microsoft Academic Search

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

G Faure

1977-01-01

429

Geological Survey of Alabama  

NSDL National Science Digital Library

This is the homepage of the Geological Survey of Alabama (GSA), a data gathering and research agency that explores and evaluates the mineral, water, energy, biological, and other natural resources of the State of Alabama and conducts basic and applied research in these fields as a public service to citizens of the State. The GSA homepage contains a geologic map of Alabama; information on GSA news and events; GSA publications; GIS data and maps; an Ask the Geologist, Hydrogeologist and Biologist link; and a Geospatial Data Clearinghouse.

430

BGS Geological Timechart  

NSDL National Science Digital Library

This is the geological time scale developed by the British Geological Survey. The principal chart is the Phanerozoic (Cambrian to Quaternary) timescale. The names of the individual periods are live links, each one leading to a chart showing the subdivisions of each period into epochs and ages. The Proterozoic and Neoproterozoic sections are also linked to further subdivisions into eras and periods. Dates are in millions of years before present. A guide on the front page describes the bases for the divisions used on this time scale and how to use it, and a downloadable version is also provide